JP2017082755A - Electric pump device and control method for electric pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric pump device for preventing abrasion wear of a bearing by restricting rotation of a motor when the bearing is not lubricated with cooling water and provide a control method for the electric pump device.SOLUTION: A microcomputer 130 causes a pulse transceiver 128 to output an electric signal when a motor part 60 for rotating impellers of a pump part 12 is started. A vibrator 126 abutted against an inner cylindrical part of the pump part 12 is vibrated by the electrical signal to transmit ultrasonic signal into the pump part 12. The microcomputer 130 performs either a normal control to cause the pulse transceiver 128 to detect reflection wave of the ultrasonic signal and to cause the motor part 60 to rotate or a protection control not to cause the motor part 60 to rotate in response to states of the detected reflection wave.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electric pump device and a method for controlling the electric pump device.

  In a vehicle equipped with a water-cooled engine, there is a case where cooling water warmed by engine heat is circulated through a heater core by an electric pump using a motor as power. The electric pump pumps the cooling water to the cooling water path by the rotation of the impeller driven by the motor, but the bearing of the rotating shaft that rotates the impeller is lubricated by the cooling water. Therefore, if the electric pump is operated (idling) in a state where the cooling water is lost, the bearing may be worn.

  In Patent Document 1, the number of rotations when the electric pump is not idling is estimated based on the voltage applied to the electric pump, and the actual number of rotations of the electric pump is equal to or greater than a predetermined threshold with respect to the estimated number of rotations. In this case, a cooling device for an internal combustion engine that determines that the electric pump is idling is disclosed.

  Patent Document 2 discloses an electric pump that determines that an electric pump is idling when a current value of a motor current of the electric pump is equal to or lower than a predetermined current value for a predetermined time.

JP 2009-68449 A JP 2006-258033 A

  However, each of the inventions described in Patent Document 1 and Patent Document 2 determines whether or not the electric pump is idling by rotating the motor of the electric pump. When it is determined that the electric pump is idling, control is performed to stop the operation of the electric pump, but the motor is rotated in a state where the bearing is not sufficiently lubricated until the operation is stopped, so that the bearing may be worn. there were.

  In view of the above-described facts, the present invention has an object to provide an electric pump device and a control method for the electric pump device that prevent rotation of the motor and prevent wear of the bearing when the bearing is not lubricated with cooling water. And

  An electric pump device according to claim 1 is arranged in a pump chamber together with a bearing and rotated, thereby impeller for pumping cooling water in the pump chamber, a motor for rotating the impeller, and a sound wave in the pump chamber. A vibration element that transmits a signal, a reflected wave detection unit that detects a reflected wave of the sound wave signal, and a sound wave signal that is transmitted from the vibration element before starting the motor, and the reflection detected by the reflected wave detection unit And a control unit that performs either a normal control for rotating the motor according to a wave mode or a protection control for not rotating the motor.

  According to the electric pump device having the above configuration, either the normal control for rotating the motor or the protection control for not rotating the motor is performed according to the reflected wave form of the sound wave signal transmitted into the pump chamber. When the reflected wave mode indicates that cooling water is present in the pump chamber, it can be determined that the bearing is lubricated with the cooling water, and therefore normal control for rotating the motor is performed.

  If the reflected wave mode indicates that there is no cooling water in the pump chamber, it can be determined that the bearing is not lubricated with cooling water. Can be prevented.

  The electric pump device according to a second aspect is the electric pump device according to the first aspect, wherein the vibration element is provided at an outer wall end of the pump chamber.

  According to the electric pump device having the above configuration, it is possible to detect a case where there is no cooling water in the pump chamber by providing the vibration element at the end of the outer wall of the pump chamber. In such a case, bearing wear can be prevented by performing protection control on the assumption that there is no cooling water in the pump chamber.

  The electric pump device according to a third aspect is the electric pump device according to the first aspect, wherein the vibration element is provided on a side surface of the outer wall of the pump chamber.

  According to the electric pump device having the above configuration, it is possible to detect a case where there is no cooling water in the pump chamber by providing the vibration element on the side surface of the outer wall of the pump chamber. In such a case, bearing wear can be prevented by performing protection control on the assumption that there is no cooling water in the pump chamber.

  The electric pump device according to claim 4 is the electric pump device according to any one of claims 1 to 3, wherein the control unit has an amplitude of the reflected wave detected by the reflected wave detection unit less than a threshold value. In this case, the normal control is performed, and the protection control is performed when the amplitude of the reflected wave detected by the reflected wave detection unit is greater than or equal to the threshold.

  The sound wave is reflected at the boundary between different media, but the aspect of the reflected wave differs depending on the medium. For example, when the medium in the pump chamber is air, the amplitude of the reflected wave is that the medium in the pump chamber is the cooling water. It will be bigger than there are.

  That is, according to the electric pump device having the above configuration, when the amplitude of the reflected wave is equal to or greater than the predetermined threshold, it is possible to prevent bearing wear by performing protection control on the assumption that there is no cooling water in the pump chamber. .

  The electric pump device according to claim 5 is the electric pump device according to claim 4, wherein the control unit is less than a water / air mixture threshold value in which the amplitude of the reflected wave detected by the reflected wave detection unit is smaller than the threshold value. In this case, the normal control is performed, and the protection control is performed when the amplitude of the reflected wave detected by the reflected wave detection unit is equal to or greater than the water / air mixture threshold.

  According to the electric pump device having the above-described configuration, when the amplitude of the reflected wave is equal to or greater than the water mixture threshold value that is smaller than the predetermined threshold value, it is assumed that cooling water and air are mixed in the pump chamber, and protection control is performed. The wear of the bearing can be prevented.

  According to a sixth aspect of the present invention, there is provided a method of controlling an electric pump device comprising: a sound wave in the pump chamber before starting a motor that rotates an impeller that pumps cooling water in the pump chamber by being disposed and rotated together with a bearing. Any of a sound wave signal transmission step for transmitting a signal, a reflected wave detection step for detecting a reflected wave of the sound wave signal, a normal control for rotating the motor according to an aspect of the reflected wave, and a protection control for not rotating the motor And a control step for performing the above.

  According to the control method of the electric pump device having the above configuration, either the normal control for rotating the motor or the protection control for not rotating the motor is performed according to the reflected wave form of the sound wave signal transmitted into the pump chamber. When the reflected wave mode indicates that cooling water is present in the pump chamber, it can be determined that the bearing is lubricated with the cooling water, and therefore normal control for rotating the motor is performed.

  If the reflected wave mode indicates that there is no cooling water in the pump chamber, it can be determined that the bearing is not lubricated with cooling water. Can be prevented.

  The method for controlling the electric pump device according to claim 7 is the method for controlling the electric pump device according to claim 6, wherein the sound wave signal transmission step starts from the vibration element provided at the outer wall end of the pump chamber. Sends sound wave signals into the room.

  According to the control method of the electric pump device having the above configuration, it is possible to detect a case where there is no cooling water in the pump chamber by providing the vibration element at the end of the outer wall of the pump chamber. In such a case, bearing wear can be prevented by performing protection control on the assumption that there is no cooling water in the pump chamber.

  The method for controlling the electric pump device according to claim 8 is the method for controlling the electric pump device according to claim 6, wherein the sound wave signal transmitting step is performed from the vibration element provided on the outer wall side surface of the pump chamber to the pump chamber. A sound wave signal is transmitted to.

  According to the control method of the electric pump device having the above configuration, it is possible to detect a case where there is no cooling water in the pump chamber by providing the vibration element on the side surface of the outer wall of the pump chamber. In such a case, bearing wear can be prevented by performing protection control on the assumption that there is no cooling water in the pump chamber.

  The electric pump device control method according to claim 9 is the electric pump device control method according to any one of claims 6 to 8, wherein, in the control step, the amplitude of the reflected wave is less than a threshold value. The normal control is performed, and the protection control is performed when the amplitude of the reflected wave is equal to or greater than the threshold value.

  The sound wave is reflected at the boundary between different media, but the aspect of the reflected wave differs depending on the medium. For example, when the medium in the pump chamber is air, the amplitude of the reflected wave is that the medium in the pump chamber is the cooling water. It will be bigger than there are.

  That is, according to the control method of the electric pump device having the above configuration, when the amplitude of the reflected wave is equal to or greater than a predetermined threshold, it is assumed that there is no cooling water in the pump chamber, and protection control is performed to Can be prevented.

  The electric pump device according to claim 10 is the control method of the electric pump device according to claim 9, wherein, in the control step, when the amplitude of the reflected wave is smaller than the threshold value when the mixed water is smaller than the threshold value, the normal pump is used. Control is performed, and the protection control is performed when the amplitude of the reflected wave is equal to or greater than the water / air mixture threshold.

  According to the control method of the electric pump device having the above configuration, when the amplitude of the reflected wave is equal to or larger than the water mixture threshold value smaller than the predetermined threshold value, the protection control is performed on the assumption that cooling water and air are mixed in the pump chamber. Thus, wear of the bearing can be prevented.

It is a longitudinal cross-sectional view (2-2 sectional view taken on the line of FIG. 2) which shows the whole water pump which concerns on the 1st Embodiment of this invention. It is the top view seen from the upper side which shows the state which removed the circuit cover in the water pump shown by FIG. It is the schematic which shows an example of the control circuit mounted in the circuit board of the water pump which concerns on the 1st Embodiment of this invention. It is the schematic which showed the one aspect | mode of operation | movement of the vibrator | oscillator in the water pump which concerns on the 1st Embodiment of this invention. It is the graph which showed the aspect of the reflected wave reflected in the boundary of the transmission wave which the vibrator in the water pump which concerns on the 1st Embodiment of this invention transmitted, the inner wall of an inner cylinder part, and the medium in an inner cylinder part (A) shows the case where the medium in the inner cylinder part is air, and (B) shows the case where the medium in the inner cylinder part is cooling water. It is the block diagram which showed an example of operation | movement of the control circuit of the water pump which concerns on the 1st Embodiment of this invention. It is the flowchart which showed an example of the idling protection process of the motor part by the control circuit of the water pump which concerns on the 1st Embodiment of this invention. It is the graph which showed the one aspect | mode of the reflected wave reflected in the boundary of the transmission wave which the vibrator | oscillator based on the 1st Embodiment of this invention transmitted, the inner wall of an inner cylinder part, and the medium in an inner cylinder part. is there. It is a longitudinal cross-sectional view which shows the whole water pump which concerns on the 2nd Embodiment of this invention. It is the schematic which showed an example of arrangement | positioning of the side vibrator in the water pump which concerns on the 2nd Embodiment of this invention, (A) is a longitudinal cross-sectional view of an inner cylinder part, (B) is an inner cylinder part. It is an overhead view from the top side. In the second embodiment of the present invention, the transmission wave from the side vibrator is reflected at the boundary between the resin layer and air constituting the inner cylinder part and the boundary between the resin layer and the cooling water, respectively, and is reflected. It is a conceptual diagram which shows the case where this occurs. It is an example of the schematic diagram which showed the aspect of the reflected wave with respect to the transmission wave of the 2nd Embodiment of this invention. (A) is the schematic which showed the case where the water pump which concerns on the 2nd Embodiment of this invention was mounted in the engine block of a vehicle by making arrow UP into an upward direction, (B) is a water pump. It is a longitudinal cross-sectional view of an inner cylinder part at the time of being mounted in a vehicle in the aspect shown to (A).

[First Embodiment]
Hereinafter, the water pump 10 as an “electric pump device and a control method of the electric pump device” according to the present embodiment will be described with reference to the drawings.

  The water pump 10 according to the present embodiment is used as a pump for pumping cooling water (liquid) for an air conditioner heater of a vehicle (automobile), for example. As shown in FIG. 1, the water pump 10 includes a pump unit 12 that accommodates the impeller 70 and pumps cooling water, and a motor unit 60 that rotates the impeller 70. Further, the water pump 10 includes a motor housing 30 that houses the motor unit 60, and a circuit device 90 that includes a circuit board 110 for driving and controlling the motor unit 60.

  Hereinafter, each said structure is demonstrated in order of the pump part 12, the motor housing 30, the motor part 60, and the circuit apparatus 90. FIG. The water pump 10 is formed in a substantially cylindrical shape as a whole, and in the following description, the arrow A direction appropriately shown in the drawings is the lower side (one axial direction of the water pump 10), and the arrow B direction is the upper side. Yes.

(About the pump unit 12)
As shown in FIG. 1, the pump unit 12 constitutes the lower part of the water pump 10. The pump unit 12 includes a pump case 14, and the pump case 14 constitutes an outer peripheral portion of the pump unit 12. The pump case 14 has a case main body portion 16, and the case main body portion 16 is formed in a substantially bottomed cylindrical shape opened upward. An impeller accommodating portion 18 that accommodates the impeller 70 is formed in the center portion of the case body portion 16, and the impeller accommodating portion 18 is formed in a substantially concave shape that opens upward. Further, a flow path 20 is formed inside the case main body portion 16 on the radially outer side of the case main body portion 16 with respect to the impeller housing portion 18. The flow path 20 is formed in a substantially U-shaped cross section that is open upward, and extends along the circumferential direction of the case body 16.

  In addition, an inlet pipe 22 is integrally formed on the bottom wall of the case body 16 at the center (the axial center of the water pump 10). The inlet pipe 22 is formed in a tubular shape and extends downward from the case main body 16. Further, the inlet pipe 22 communicates with the impeller accommodating portion 18 so that cooling water flows from the inlet pipe 22 into the case main body portion 16.

  Further, an outlet pipe (not shown) is integrally formed on the outer peripheral portion of the case main body 16. The outlet pipe is formed in a tubular shape and extends from the side wall of the case main body 16 in a direction orthogonal to the axis of the water pump 10. The outlet pipe communicates with the flow path 20 so that the cooling water that has flowed into the case body 16 flows out of the outlet pipe.

  A pump-side flange portion 26 is integrally formed at the open end portion of the case body portion 16, and the pump-side flange portion 26 projects from the case body portion 16 to the outside in the radial direction of the case body portion 16. At the same time, it is formed in a substantially ring shape over the entire circumference of the case body 16. A substantially cylindrical rib 26A is erected on the upper surface of the pump-side flange portion 26. The rib 26A is formed over the entire circumference of the case main body portion 16, and is directed upward from the pump-side flange portion 26. It is protruding.

(About motor housing 30)
As shown in FIG. 1, the motor housing 30 constitutes an intermediate portion in the vertical direction of the water pump 10 and is disposed on the upper side with respect to the pump portion 12. The motor housing 30 is made of a synthetic resin such as PPA (polyphthalamide) resin, and is formed in a substantially bottomed cylindrical shape that is opened upward as a whole, and has an inlet pipe 22 (the axis of the water pump 10). ) And the same axis. Specifically, the motor housing 30 has an outer cylindrical portion 32 that constitutes a radially outer portion of the motor housing 30, and the outer cylindrical portion 32 is formed in a substantially bottomed cylindrical shape that is open upward. ing. Further, the motor housing 30 has an inner cylinder portion 34 that constitutes a radially inner portion of the motor housing 30. The inner cylindrical portion 34 is formed in a substantially bottomed cylindrical shape that is opened downward, and the open end (lower end) of the inner cylindrical portion 34 is coupled to the bottom wall of the outer cylindrical portion 32.

  The space between the outer cylinder part 32 and the inner cylinder part 34 is a stator accommodating part 36 for accommodating the stator 80, and the stator accommodating part 36 is a substantially annular space opened upward. Is formed. Furthermore, a space inside the inner cylinder portion 34 is a rotor accommodating portion 38 for accommodating a rotor 62 described later.

  A first coupling portion 40 is integrally formed at the lower end portion of the outer cylinder wall 32 </ b> A constituting the outer peripheral portion of the outer cylinder portion 32. The first coupling portion 40 protrudes from the outer cylinder wall 32A to the outside in the radial direction of the motor housing 30, is formed in a substantially ring shape over the entire circumference of the outer cylinder wall 32A, and the pump-side flange portion 26 described above. They are arranged facing each other in the vertical direction. Further, a rib housing recess 40A is formed on the lower surface of the first coupling portion 40 at a position corresponding to the rib 26A of the pump-side flange portion 26 described above. 40 A of rib accommodating recessed parts are open | released below, and are formed in the annular | circular shape (ring shape) seeing from the axial direction of the motor housing 30. As shown in FIG. And the 1st coupling | bond part 40 and the pump side flange part 26 are couple | bonded in the state in which the rib 26A of the pump case 14 was accommodated in the rib accommodating recessed part 40A. Further, in this state, the bottom wall of the outer cylindrical portion 32 enters the pump case 14 and the pump case 14 and the rotor accommodating portion 38 are communicated with each other.

  On the other hand, a second coupling portion 42 is formed integrally with the upper end portion of the outer cylindrical wall 32A. The second coupling portion 42 protrudes from the outer cylindrical wall 32A to the outside in the radial direction of the motor housing 30, and is formed in a predetermined shape over the entire circumference of the outer cylindrical wall 32A (see FIG. 1). Further, the surrounding wall 42 </ b> A is integrally formed on the upper surface of the second coupling portion 42 at the outer peripheral portion of the second coupling portion 42. The surrounding wall 42 </ b> A protrudes upward from the second coupling portion 42 and is formed over the entire circumference of the second coupling portion 42.

  Further, as shown in FIG. 2, the second coupling portion 42 is integrally formed with a connector portion 44 that is fitted to an external connector (not shown). The connector portion 44 is formed in a substantially bottomed rectangular tube shape opened upward (arrow B direction side in FIG. 1), and protrudes upward from the second coupling portion 42. Further, the motor housing 30 is provided with a connector terminal 46 as a “terminal” connected to an external connector, and the connector terminal 46 is made of brass. One end portion of the connector terminal 46 is disposed inside the connector portion 44. The connector terminal 46 is bent into a predetermined shape, and the other end of the connector terminal 46 extends upward from the motor housing 30 and is connected to a circuit board 110 described later.

  As shown in FIG. 1, a substantially cylindrical support portion 48 is integrally formed on the bottom wall of the inner cylinder portion 34 (rotor accommodating portion 38) at the center portion. The support portion 48 is disposed coaxially with the inlet pipe 22 of the pump portion 12 and protrudes downward from the bottom wall of the inner cylinder portion 34. Furthermore, a cylindrical rotary shaft 50 is provided in the inner cylinder portion 34, and the rotary shaft 50 is disposed coaxially with the support portion 48. The upper end portion of the rotation shaft 50 is fixedly supported by the support portion 48, and the rotation shaft 50 protrudes downward from the support portion 48.

  Furthermore, a plurality of recesses 52 opened downward are formed in the bottom wall of the inner cylinder portion 34, and the recesses 52 are arranged in the circumferential direction of the support portion 48 at positions radially outside the support portion 48. Are arranged along. As a result, the cooling water in the pump unit 12 also flows into the recess 52. Note that when the water pump 10 is used in a state where the water pump 10 is disposed upside down, cast iron, impurities, and the like generated in the piping and the like can be stored in the recess 52. Thereby, it is comprised so that it may suppress that the bearing 64 mentioned later is worn out by generation | occurrence | production of such an impurity. In addition, the space in the inner cylinder part 34 and the space in the pump part 12 comprise what is called a pump chamber filled with cooling water.

(About the motor unit 60)
As shown in FIG. 1, the motor unit 60 is a brushless DC motor that includes a rotor 62 and a stator 80. The rotor 62 is accommodated in the rotor accommodating portion 38 of the motor housing 30. Further, the rotor 62 is formed in a substantially cylindrical shape, and is disposed on the outer side in the radial direction of the rotation shaft 50 and coaxially with the rotation shaft 50. A plurality of magnets (not shown) are provided inside the rotor 62, and the magnets are arranged along the circumferential direction of the rotor 62. A bearing 64 is provided on the radially inner side of the rotor 62 so as to be separated from the rotor 62. The bearing 64 is formed in a substantially cylindrical shape and is rotatably supported on the rotary shaft 50. And the bearing 64 and the rotor 62 are integrally shape | molded by the mold part 66 comprised with the resin material. Thereby, the rotor 62 is rotatably supported by the rotating shaft 50 via the bearing 64. The bearing 64 is disposed in the pump chamber and is lubricated by cooling water.

  Further, a first disk portion 72 and a blade 74 constituting the impeller 70 are integrally formed at the lower end portion of the mold portion 66. The first disk portion 72 is formed in a substantially disk shape, and is arranged coaxially with the rotation shaft 50 with the plate thickness direction being the axial direction of the rotation shaft 50. The blade 74 projects upward from the first disk portion 72. Further, a second disk portion 76 constituting the impeller 70 is provided below the blade 74. The second disk portion 76 is formed in a substantially disk shape, is disposed so as to face the first disk portion 72 via the blade 74, and is integrally coupled to the blade 74.

  The stator 80 includes a stator core 82 formed in an annular shape and a brass winding 84 having conductivity, and is accommodated in the stator accommodating portion 36 of the motor housing 30. The stator core 82 is composed of a plurality of steel plates punched into a predetermined shape, and the steel plates are stacked in the vertical direction with the plate thickness direction being the vertical direction. The stator core 82 is formed with a plurality of tooth portions 82A extending outward in the radial direction of the stator core 82.

  Winding 84 is wound around tooth portion 82 </ b> A of stator core 82. Thereby, winding part 84A wound along the outer peripheral part of teeth part 82A is formed. The terminal portion of the winding 84 extends upward from the motor housing 30 (stator accommodating portion 36), and is joined to a circuit board 110 described later by soldering. An insulating member 85 (see FIG. 1) is interposed between the winding portion 84A and the tooth portion 82A.

  The stator 80 is covered with a stator cover 86. The stator cover 86 is made of a steel plate and is formed in a substantially bottomed cylindrical shape opened upward. Further, a circular arrangement hole 86A (see FIG. 1) is formed through the bottom wall of the stator cover 86 in the vertical direction. The stator 80 is fitted into the stator cover 86, and the stator 80 and the stator cover 86 are accommodated in the stator accommodating portion 36. In this state, the inner cylindrical portion 34 of the motor housing 30 is disposed inside the arrangement hole 86A.

  A stator cover flange portion 86 </ b> B is integrally formed at the open end (upper end) of the stator cover 86. The stator cover flange portion 86B extends from the open end of the stator cover 86 to the outside in the radial direction of the stator cover 86, and is disposed above the second coupling portion 42 of the motor housing 30 and inside the surrounding wall 42A. Yes. And the stator cover flange part 86B is being fixed to the 2nd coupling part 42 of the motor housing 30 with the circuit cover flange part 112A mentioned later.

(About the circuit device 90)
As shown in FIG. 1, the circuit device 90 constitutes an upper portion of the water pump 10. The circuit device 90 includes a plate unit 92 as a “fixing member unit”, a circuit board 110, and a circuit cover 112.

  The plate unit 92 is disposed on the upper side (one side in the longitudinal direction) of the motor housing 30 and is formed in a substantially circular plate shape as a whole. The plate unit 92 includes a fixing plate 94 as a “fixing member” and a base portion 104 made of resin. The fixed plate 94 is made of a metal plate (in the present embodiment, a steel plate) and is formed by punching and bending the plate. The fixed plate 94 includes a ring plate portion 96 having a substantially annular plate shape, and the ring plate portion 96 constitutes a lower portion of the plate unit 92. The ring plate portion 96 is disposed with the plate thickness direction being the vertical direction, and the lower surface of the ring plate portion 96 is in contact with the upper surface of the stator cover flange portion 86B (see FIG. 1). In addition, a plurality of (four locations in the present embodiment) fixing holes are formed through the ring plate portion 96. A screw 120 (see FIG. 2) is inserted into the fixing hole, and the fixing plate 94 (plate unit 92) is fastened and fixed to the stator cover flange portion 86B. Accordingly, the fixed plate 94 (plate unit 92) is fixed to the motor housing 30 via the stator cover 86.

  The ring plate portion 96 is integrally formed with a plurality of (three in this embodiment) fixing pieces 98 for fixing a circuit board 110 to be described later. The fixed piece 98 extends upward (bent upward) from the outer periphery of the ring plate portion 96, and the distal end portion of the fixed piece 98 is bent radially inward of the ring plate portion 96. And the front-end | tip part of the fixed piece 98 is made into the fixed part 98A, and the fixed part 98A is arrange | positioned facing the ring plate part 96 in the up-down direction. The fixing portion 98A is formed with a burring 98B as a “fastened portion” for fastening and fixing a circuit board 110 to be described later. The burring 98B protrudes downward from the fixing portion 98A, It is formed in a substantially bottomed cylindrical shape that opens upward.

  As shown in FIG. 2, the circuit board 110 is formed in a substantially disk shape. The circuit board 110 is disposed above the plate unit 92 with the plate thickness direction being the vertical direction, and the lower surface of the circuit board 110 is in contact with the upper surface of the fixing portion 98A of the fixing plate 94 (see FIG. 1). The circuit board 110 is formed with a mounting hole (not shown) at a position corresponding to the burring 98B of the fixing plate 94 described above, and a tapping screw 122 as a “fastening member” is inserted into the mounting hole and the burring 98B. Then, the circuit board 110 is fixed to the plate unit 92 (fixed plate 94) by the tapping screw 122. In addition, a GND pattern (not shown) is formed on the lower surface of the circuit board 110 at the contact portion with the upper surface of the fixing portion 98A.

  In addition, the terminal portion of the winding 84 extending upward from the base portion 104 is joined to the circuit board 110 by soldering, and the other end portion of the connector terminal 46 is joined by soldering. Furthermore, a plurality of circuit elements 110 </ b> A are mounted on the upper and lower surfaces of the circuit board 110. Furthermore, the heat radiating plate portion 100 connected to the fixed plate 94 is disposed between the circuit board 110 and the bottom wall of the rotor accommodating portion 38 of the motor housing 30 in close proximity to each other (see FIG. 1).

  A vibrator 126 that vibrates when a pulse-like electric signal is applied is provided at the outer wall end portion of the inner cylindrical portion 34 in contact with the outer wall end portion. The vibrator 126 is, for example, a piezoelectric element made of piezoelectric ceramic. The vibrator 126 vibrates by an electric signal applied from a pulse transmitter / receiver 128 (see FIG. 2) mounted on the circuit board 110, and applied electric power. A sound wave corresponding to the frequency of the signal pulse is transmitted from the outer wall of the inner cylindrical portion 34 to the inner cylindrical portion 34.

  The pulse transmitter / receiver 128 includes an oscillation circuit that generates a pulsed electric signal applied to the vibrator 126 and a reception circuit that receives a sound wave transmitted from the vibrator 126. As an example, the oscillation circuit uses a crystal resonator or a ceramic resonator, and generates a pulse having a frequency unique to these elements. The receiving circuit is a circuit using an element that vibrates by a received sound wave and generates an electric signal, and a piezoelectric element or the like is used as the element. The pulse transmitter / receiver 128 and the vibrator 126 are electrically connected by, for example, a flexible connector or the like (not shown), and an electric signal is applied to the vibrator 126 from the pulse transmitter / receiver 128 through the flexible connector or the like. The The frequency of the electrical signal is arbitrary, but is 20 kHz or more as an example. When an electric signal having such a frequency is applied, the vibrator 126 emits a so-called ultrasonic wave.

  As shown in FIG. 1, the circuit cover 112 is made of a steel plate. The circuit cover 112 is formed in a substantially bottomed cylindrical shape that opens downward, and is disposed coaxially with the rotary shaft 50. A circuit cover flange portion 112A is integrally formed at the opening end of the circuit cover 112, and the circuit cover flange portion 112A protrudes from the opening end of the circuit cover 112 to the outside in the radial direction of the circuit cover 112. The circuit cover 112 is formed over the entire circumference. The circuit cover 112 covers the circuit board 110 and the plate unit 92 and closes the upper end portion of the motor housing 30. The circuit cover flange portion 112 </ b> A is fastened to the stator cover flange portion 86 </ b> B by a tapping screw 124 and is fixed to the motor housing 30.

  FIG. 3 is a schematic diagram showing an example of the control circuit 200 mounted on the circuit board 110 of the water pump 10 according to the present embodiment. In the inverter circuit 134, the ignition switch 144 is turned on, the electric power supplied from the vehicle-mounted battery 140 is switched, and a voltage to be applied to the coil of the stator 80 of the motor unit 60 is generated. For example, the inverters FET 134A and 134D perform switching for generating a voltage to be applied to a U-phase coil, the inverters FET 134B and 134E to a V-phase coil, and the inverters FET 134C and 134F to a W-phase coil.

  The drains of the inverters FET 134A, 134B, and 134C are connected to the positive electrode of the on-vehicle battery 140. The sources of the inverters FET 134D, 134E, and 134F are connected to the negative electrode of the battery 140.

  In the present embodiment, the rotational speed and position (rotational position) of the rotor 62 are detected by the induced voltage generated by the rotation of the rotor 62 of the motor unit 60. In general, a brushless DC motor detects a magnetic field of a magnet of a rotor 62 or a sensor magnet provided coaxially with a rotating shaft 50 by a Hall element, and the rotational speed and position (rotational position) of the rotor 62 based on the detected magnetic field. Is detected. However, since the motor unit 60 according to the present embodiment is used in the water pump 10 that pumps the cooling water heated by the engine, it is exposed to engine-derived heat during operation. Since the Hall element that is a semiconductor is vulnerable to heat, the motor unit 60 according to the present embodiment does not use the Hall element, and detects the rotational speed and position of the rotor 62 based on the induced voltage generated in the coil of the non-energized phase. To do.

  The induced voltage is a sinusoidal analog signal that changes in accordance with the rotation of the rotor 62. In this embodiment, the induced voltage is converted into a rectangular wave pulse signal by the position detection circuit 136 including a comparator and input to the microcomputer 130. To do.

  The microcomputer 130 calculates the position of the rotor 62 from the signal input from the position detection circuit 136, and based on the calculated position of the rotor 62 and the command signal input from the ECU 142, which is a host control device, the inverter circuit 134. The duty ratio of PWM (Pulse Width Modulation) control related to the switching control is calculated. An input circuit 148 is provided between the ECU 142 and the microcomputer 130. The input circuit 148 is a circuit that mediates communication between the ECU 142 and the microcomputer 130. For example, when the communication protocol used by the ECU 142 is LIN (Local Interconnect Network), the protocol of the input signal such as a command signal from the ECU 142 is converted into a protocol that can be interpreted by the microcomputer 130. Further, the operation status of the motor unit 60 is transmitted from the microcomputer 130 to the ECU 142 as an output signal. The protocol of the output signal is converted into LIN and transmitted to the ECU 142.

  The ECU 142 is connected to a water temperature sensor 146 that detects the temperature of the cooling water of the engine. As the temperature of the cooling water rises, for example, the motor unit 60 so that the amount of cooling water discharged from the water pump 10 increases. To control the rotation speed. The water temperature sensor 146 is provided at one corner of a cooling water flow path such as a water jacket or a radiator of the engine.

  The duty ratio signal (PWM control signal) calculated by the microcomputer 130 is output to the inverter circuit 134 via the pre-driver 132, and the inverter circuit 134 generates a voltage based on the duty ratio, and the coil of the motor unit 60. Apply to. In the present embodiment, the pre-driver 132 and the inverter circuit 134 constitute a motor drive circuit 138 that generates a voltage to be applied to the coil of the motor unit 60.

  Further, as shown in FIG. 1, a vibrator 126 is provided at the outer wall end portion of the inner cylinder portion 34 disposed on the upper side with respect to the pump portion 12. The vibrator 126 is connected to a pulse transmitter / receiver 128 mounted on the circuit board 110 constituting the control circuit 200, and the pulse transmitter / receiver 128 is connected to the microcomputer 130.

  Next, the operation and effect of the present embodiment will be described. FIG. 4 is a schematic diagram showing an aspect of the operation of the vibrator 126 in the water pump 10 according to the present embodiment. The vibrator 126 vibrates in accordance with the electrical signal input from the pulse transmitter / receiver 128 and propagates the transmission wave 152 from the C end to the D end of the inner cylindrical portion 34. Since the sound wave is reflected at the boundary between different media, the transmitted wave 152 reaching the D end of the inner cylindrical portion 34 is reflected and reflected at the boundary between the medium existing in the inner cylindrical portion 34 and the D end. A wave 154 is obtained. The pulse transmitter / receiver 128 receives the reflected wave 154 shown in FIG.

  In FIG. 4, since the inner cylinder portion 34 is filled with the cooling water 150, the transmission wave 152 is reflected at the boundary between the D end of the inner cylinder portion 34 and the cooling water 150. When the cooling water 150 does not exist in the inner cylinder part 34, the transmission wave 152 is reflected at the boundary between the D end of the inner cylinder part 34 and air. In the present embodiment, either normal control for rotating the motor unit 60 or protection control for not rotating the motor unit 60 is performed according to the mode of the reflected wave 154.

  FIG. 5 shows an aspect of the reflected wave 154 reflected at the boundary between the transmission wave 152 transmitted by the vibrator 126 and the inner wall of the inner cylinder part 34 and the medium in the inner cylinder part 34 in the water pump 10 according to the present embodiment. (A) shows the case where the medium in the inner cylinder part 34 is air, and (B) shows the case where the medium in the inner cylinder part 34 is cooling water.

  5A, a reflected wave 154A is generated for the transmission wave 152, and a reflected wave 154W is generated for the transmission wave 152 in FIG. Comparing the reflected wave 154A and the reflected wave 154W, the reflected wave 154A when the medium in the inner cylinder part 34 is air is more than the reflected wave 154W when the medium in the inner cylinder part 34 is cooling water. The amplitude is large. In the present embodiment, it is determined whether or not the medium filling the inner cylindrical portion 34 is the cooling water 150 based on the amplitude of the reflected wave 154.

  FIG. 6 is a block diagram showing an example of the operation of the control circuit 200 of the water pump 10 according to the present embodiment. When the microcomputer 130 in the control circuit 200 receives an input signal for operating the water pump 10 via the input circuit 148, the microcomputer 130 causes the pulse transmitter / receiver 128 to output an electric signal for operating the vibrator 126.

  The vibrator 126 vibrates in accordance with the electric signal output from the pulse transmitter / receiver 128 and outputs a transmission wave 152 to the inner cylinder portion 34 of the water pump 10. The reflected wave 154 generated by reflecting the transmission wave 152 in the inner cylinder portion 34 is received by the pulse transmitter / receiver 128, and the amplitude of the reflected wave 154 is compared with a predetermined reference value 160 by the comparator 162 in the microcomputer 130. The

  When the amplitude of the reflected wave 154 is smaller than the reference value 160, the microcomputer 130 determines that the cooling water 150 exists in the inner cylinder portion 34 and operates the motor drive circuit 138 to drive the motor portion 60. A command signal to be output is output to the motor drive circuit 138 and an output signal indicating that the motor unit 60 is to be driven is output to the ECU 142 via the input circuit 148.

  If the amplitude of the reflected wave 154 is greater than or equal to the reference value 160, the microcomputer 130 determines that the cooling water 150 does not exist in the inner cylinder portion 34 and outputs a command signal for operating the motor drive circuit 138. Then, an output signal indicating that the motor unit 60 is not driven is output to the ECU 142 via the input circuit 148.

  FIG. 7 is a flowchart showing an example of the idling protection process of the motor unit 60 by the control circuit 200 of the water pump 10 according to the present embodiment. The process of FIG. 7 is started when a command for operating the water pump 10 is input from the ECU 142. In Step 700, the vibrator 126 is vibrated to input the transmission wave 152 to the inner cylinder portion 34 of the water pump 10, and the transmission wave 152 is generated at the boundary between the inner wall of the inner cylinder portion 34 and the medium in the inner cylinder portion 34. A reflected wave 154 generated by the reflection is received.

  In step 702, the amplitude (measured value) of the reflected wave 154 is compared with a reference value to determine whether or not the measured value is greater than or equal to the reference value. The relationship between the reference value and the measured value is as shown in FIG. 8, for example. In the present embodiment, the reflected wave amplitude value V2, which is a measured value, is compared with the reference value V1. Although the specific numerical value of the reference value V1 can be roughly calculated based on the sound speed and the density of the PPA resin in the PPA resin constituting the inner cylinder portion 34, and the sound speed and the density of the cooling water in the cooling water, Since it is also influenced by the shape in the inner cylinder part 34, it determines concretely using an actual machine etc.

  If the determination in step 702 is affirmative, it is considered that the cooling water 150 does not exist in the inner cylinder portion 34. Therefore, in step 706, fail processing (protection control) that does not cause the motor portion 60 to run idle is executed and the processing is terminated. .

  In the case of negative determination in step 702, it is considered that the cooling water 150 exists in the inner cylinder portion 34. Therefore, in step 704, normal control for rotating the motor portion 60 is performed as usual, and the water pump 10 is driven. The process is terminated.

  As described above, according to the present embodiment, the cooling water 150 exists in the water pump 10 by comparing the amplitude of the reflected wave 154 of the transmission wave 152 output from the vibrator 126 with the reference value. Whether or not the bearing 64 is lubricated with cooling water can be determined before rotating the motor unit 60. When the cooling water 150 is not present in the water pump 10, the motor unit 60 is not rotated, so that the operation of the water pump 10 in a situation in which lubrication by the cooling water cannot be expected can be avoided and wear of the bearing 64 can be prevented.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 9 is a longitudinal sectional view showing the entire water pump according to the present embodiment. This embodiment is different from the first embodiment in that a side vibrator 226 is provided on the side surface of the inner cylindrical portion 34 instead of the vibrator 126. The reason why the side vibrator 226 is provided in place of the vibrator 126 is that when air and cooling water are mixed in the inner cylinder portion 34, the inner cylinder is used in detection of the reflected wave based on the transmission wave from the vibrator 126. This is because there is a risk of erroneous determination that the inside of the portion 34 is filled with cooling water. If air and cooling water are mixed in the inner cylinder portion 34, the bearing 64 in the water pump 10 is not lubricated with the cooling water, so that a fail process (protection control) that does not cause the motor portion 60 to run idle is executed. There is a need. In this embodiment, since the configuration other than the side vibrator 226 is the same as that of the first embodiment, detailed description thereof is omitted.

  10A and 10B are schematic views showing an example of the arrangement of the side vibrator 226 in the water pump 10 according to the present embodiment. FIG. 10A is a longitudinal sectional view of the inner cylinder portion 34, and FIG. 10B is an inner cylinder. 4 is an overhead view from the top side of a portion 34. FIG.

  As shown in FIGS. 10A and 10B, the side vibrator 226 is disposed on the side surface of the inner cylinder portion 34. As shown in FIG. 10 (B), the side vibrator 226 has a curvature on the side contacting the side surface of the inner cylinder portion 34 so that the curved surface constituting the side surface of the inner cylinder portion 34 comes into surface contact. It is substantially equal to the curvature of the side surface of the portion 34. The side vibrator 226 is electrically connected to the pulse transmitter / receiver 128 by a flexible connector or the like (not shown), for example, and an electric signal is applied from the pulse transmitter / receiver 128 to the side vibrator 226 via the flexible connector or the like. . By applying such an electric signal, the side vibrator 226 emits a so-called ultrasonic wave.

  In the present embodiment, the side vibrator 226 is provided on the outer wall of the inner cylinder portion 34 so that a state where air and cooling water are mixed in the inner cylinder portion 34 can be detected.

  In the present embodiment, the side vibrator 226 is operated to determine the presence or absence of cooling water in the inner cylinder portion 34. Specifically, the side vibrator 226 is vibrated to input a transmission wave to the inner cylinder portion 34, and the transmission wave is reflected at the boundary between the inner wall of the inner cylinder portion 34 and the medium in the inner cylinder portion 34. The reflected wave is received by the pulse transmitter / receiver 128.

  In FIG. 11, the transmission wave from the side vibrator 226 is reflected at the boundary between the resin layer 34 </ b> A and the air constituting the inner cylinder portion 34 and the boundary between the resin layer 34 </ b> A and the cooling water to generate a reflected wave. It is a conceptual diagram which shows a case.

In FIG. 11, P ₁ is the amplitude of the transmission wave from the side vibrator 226, and P ₂ is the reflection generated by the transmission wave from the side vibrator 226 being reflected at the boundary between the resin layer 34 </ _b > A and air. The amplitude of the wave. P ₃ is the amplitude of the reflected wave generated when the transmission wave from the side vibrator 226 is reflected at the boundary between the resin layer 34A and the cooling water.

In FIG. 11, A ₁ is the contact area of the resin layer 34A in surface contact with the side vibrator 226, A ₂ is the contact area of air with the resin layer 34A, and A ₃ is the contact of cooling water with the resin layer 34A. It is an area. And A ₁ = A ₂ + A ₃ .

In FIG. 11, Z ₁ is the acoustic impedance of the resin that constitutes the resin layer 34A, Z ₂ is the acoustic impedance of the air, and Z ₃ is the acoustic impedance of the water that constitutes the cooling water. Z ₁ is about 2.0 to 2.5 × 10 ⁶ kgm ² / s, although it varies depending on the type of resin. Z ₂ is 0.00004 × 10 ⁶ kgm ² / s, and Z ₃ is 1.5 × 10 ⁶ kgm ² / s.

The sound wave reflectance R ₁ at the boundary between the resin layer 34A and the air is calculated by the following equation (1).

Further, the reflectance R ₂ of the sound wave at the boundary between the resin layer 34A and the cooling water is calculated by the following equation (2).

The amplitude of the reflected wave with respect to the transmitted wave is proportional to the reflectance described above, and the medium (air, water) with respect to the resin layer 34A with respect to the contact area A ₁ of the resin layer 34A that is in surface contact with the side vibrator 226 that is the sound source. Is proportional to the contact area (A ₂ , A ₃ ). Therefore, when the transmission wave has the amplitude P ₁ , the amplitude P ₂ of the reflected wave generated by being reflected at the boundary between the resin layer 34A and the air is calculated by the following equation (3).

Further, when the transmission wave has an amplitude P ₁ , the amplitude P ₃ of the reflected wave generated by being reflected at the boundary between the resin layer 34A and the cooling water is calculated by the following equation (4).

When air and cooling water are mixed in the inner cylindrical portion 34, the detected reflected wave amplitude P _AW is the sum of P ₂ and P _{3 as} shown in the following equation (5). is there.

  By using the above formulas (3) to (5), the amplitude of the reflected wave when there is no cooling water in the inner cylinder portion 34, and the reflected wave when the inner cylinder portion 34 is filled with cooling water. The amplitude and the amplitude of the reflected wave when air and cooling water are mixed in the inner cylindrical portion 34 can be calculated.

  FIG. 12 is an example of a schematic diagram illustrating reflected waves 154A, 154AW, and 154W with respect to the transmission wave 152. The reflected wave 154A is a reflected wave when there is no cooling water in the inner cylindrical portion 34, and the reflected wave 154W is a reflected wave when the inner cylindrical portion 34 is filled with cooling water. The reflected wave 154AW is a reflected wave when air and cooling water are mixed in the inner cylindrical portion 34.

  The amplitude of the reflected wave 154A can be calculated using the above equation (3), the amplitude of the reflected wave 154W can be calculated using the above equation (4), and the amplitude of the reflected wave 154AW can be calculated using the above equation (5). In the present embodiment, the amplitudes of the reflected waves 154A, 154W, and 154AW are calculated using the above equations (3) to (5), and the reference value V3 for identifying the reflected wave 154W and the reflected wave 154AW is determined. Can be determined. Since there may be a difference between the calculated value and the actually measured value, in this embodiment, the reference wave V3 is determined by optimizing the waveforms and amplitudes of the reflected waves 154A, 154W, and 154AW through an experiment using an actual machine. The reference value V3 is smaller than the reference value V1 of the first embodiment because it is necessary to identify the reflected wave 154AW having an amplitude smaller than that of the reflected wave 154A. Also in the first embodiment, the reflected wave 154W and the reflected wave 154AW may be identified using the reference value V3.

  In the present embodiment, in step 702 of the flowchart shown in FIG. 7, the amplitude (measured value) of the reflected wave 154 and the reference value V3 are compared to determine whether or not the measured value is greater than or equal to the reference value V3. If the determination in step 702 is affirmative, it is considered that the cooling water 150 does not exist in the inner cylinder portion 34 or air and cooling water are mixed. In either case, since the bearing 64 in the water pump 10 is not lubricated with the cooling water, a fail process (protection control) that does not cause the motor unit 60 to run idle is executed in step 706 and the process is terminated.

  FIG. 13A is a schematic diagram showing a case where the water pump 10 according to the present embodiment is mounted on an engine block of a vehicle with an arrow UP as an upward direction. In FIG. 13 (A), the water pump 10 is mounted on the vehicle in an inverted state from the states shown in FIGS. 1 and 9, and therefore when air and cooling water are mixed in the inner cylinder portion 34. The cooling water stays on the inner wall on the side (end) where the vibrator 126 is provided in the first embodiment.

  FIG. 13B is a vertical cross-sectional view of the inner cylinder portion 34 when the water pump 10 is mounted on a vehicle in the mode shown in FIG. In the inner cylinder portion 34, air 170 and cooling water 150 </ b> A are mixed, and the cooling water 150 </ b> A stays at the bottom in the inner cylinder portion 34. When the side vibrator 226 is operated, the transmission wave from the side vibrator 226 is reflected at the boundary between the inner wall of the inner cylindrical portion 34 and the cooling water 150A and the boundary between the inner wall of the inner cylindrical portion 34 and the air 170, respectively. The pulse transmitter / receiver 128 detects the waveform and amplitude of the reflected wave 154AW shown in FIG.

  Even when the water pump 10 is mounted on the vehicle in a manner other than that shown in FIG. 13, it is possible to determine whether or not the inner cylinder portion 34 is filled with cooling water by operating the side vibrator 226. . In the present embodiment, when a reflected wave 154AW indicating that air and cooling water are mixed in the inner cylindrical portion 34 is detected by a sound wave signal from the side vibrator 226, the motor portion 60 is Execute fail processing (protection control) that does not cause idling.

  As described above, according to the present embodiment, the water pump 10 in a situation where the lubrication by the cooling water cannot be expected by detecting the case where the air 170 and the cooling water 150A are mixed in the inner cylindrical portion 34. The wear of the bearing 64 can be prevented.

DESCRIPTION OF SYMBOLS 10 ... Water pump, 12 ... Pump part, 14 ... Pump case, 16 ... Case main-body part, 18 ... Impeller accommodating part, 20 ... Flow path, 22 ... Inlet pipe, 26 ... Pump side flange part, 26A ... Rib, 30 ... Motor housing 32 ... outer cylinder part 32A ... outer cylinder wall 34 ... inner cylinder part 36 ... stator accommodating part 38 ... rotor accommodating part 40 ... coupling part 40A ... rib accommodating recess 42 ... coupling part 42A DESCRIPTION OF SYMBOLS ... Surrounding wall, 44 ... Connector part, 46 ... Connector terminal, 48 ... Support part, 50 ... Rotating shaft, 52 ... Recessed part, 60 ... Motor part, 62 ... Rotor, 64 ... Bearing, 66 ... Mold part, 70 ... Impeller, 72 ... 1st disk part, 74 ... Blade, 76 ... 2nd disk part, 80 ... Stator, 82 ... Stator core, 82A ... Teeth part, 84 ... Winding, 84A ... Winding part, 85 ... Insulating member, 86 ... Stay Cover, 86A ... Arrangement hole, 86B ... Stator cover flange part, 90 ... Circuit device, 92 ... Plate unit, 94 ... Fixed plate, 96 ... Ring plate part, 98 ... Fixed piece, 98A ... Fixed part, 98B ... Burring, 100 ... Heat dissipation plate part, 104 ... Base part, 110 ... Circuit board, 110A ... Circuit element, 112 ... Circuit cover, 112A ... Circuit cover flange part, 120 ... Screw, 122 ... Tapping screw, 124 ... Tapping screw, 126 ... Oscillator , 128 ... pulse transmitter / receiver, 130 ... microcomputer, 132 ... pre-driver, 134 ... inverter circuit, 134A, 134B, 134C, 134D, 134E, 134F ... inverter FET, 136 ... position detection circuit, 138 ... motor drive circuit, 140 ... Battery, 142... ECU, 144. Niss switch, 146 ... water temperature sensor, 148 ... input circuit, 150 ... cooling water, 152 ... transmitted wave, 154 ... reflected wave, 154A, 154W ... reflected wave, 160 ... reference value, 162 ... comparator, 170 ... air, 200: Control circuit, 226: Side vibrator, V1: Reference value, V2: Reflected wave amplitude value, V3: Reference value

Claims (10)

An impeller that pumps cooling water in the pump chamber by being disposed and rotated in the pump chamber together with the bearing;
A motor for rotating the impeller;
A vibration element for transmitting a sound wave signal into the pump chamber;
A reflected wave detector for detecting a reflected wave of the sound wave signal;
Either normal control for transmitting a sound wave signal from the vibration element before starting the motor and rotating the motor according to the reflected wave detected by the reflected wave detection unit or protection control for not rotating the motor. A control unit that
Including electric pump device.   The electric pump device according to claim 1, wherein the vibration element is provided at an end portion of an outer wall of the pump chamber.   The electric pump device according to claim 1, wherein the vibration element is provided on a side surface of the outer wall of the pump chamber.   The control unit performs the normal control when the amplitude of the reflected wave detected by the reflected wave detection unit is less than a threshold, and when the amplitude of the reflected wave detected by the reflected wave detection unit is equal to or greater than the threshold. The electric pump device according to claim 1, wherein the protection control is performed.   The control unit performs the normal control when the amplitude of the reflected wave detected by the reflected wave detection unit is less than a water-mixing threshold value that is smaller than the threshold value, and the reflected wave detection unit detects the reflected wave detected by the reflected wave detection unit. The electric pump device according to claim 4, wherein the protection control is performed when an amplitude is equal to or greater than a threshold value when the water is mixed. A sound wave signal sending step for sending a sound wave signal into the pump chamber before starting a motor for rotating an impeller that is arranged and rotated in the pump chamber together with the bearing to rotate the impeller that pumps cooling water in the pump chamber;
A reflected wave detecting step for detecting a reflected wave of the sound wave signal;
A control step for performing either normal control for rotating the motor in accordance with the reflected wave mode or protection control for not rotating the motor;
A method for controlling an electric pump device including:   The method of controlling an electric pump device according to claim 6, wherein in the sound wave signal transmitting step, a sound wave signal is transmitted into the pump chamber from a vibration element provided at an outer wall end of the pump chamber.   The method of controlling an electric pump device according to claim 6, wherein in the sound wave signal transmitting step, a sound wave signal is transmitted into the pump chamber from a vibration element provided on a side surface of the outer wall of the pump chamber.   The said control step WHEREIN: The said normal control is performed when the amplitude of the said reflected wave is less than a threshold value, The said protection control is performed when the amplitude of the said reflected wave is more than the said threshold value. Method for controlling the electric pump device.   In the control step, the normal control is performed when the amplitude of the reflected wave is less than the water mixture threshold value smaller than the threshold value, and the protection control is performed when the reflected wave amplitude is equal to or greater than the water mixture threshold value. The control method of the electric pump apparatus of Claim 9.