JP2012147517A - Linear motor device and linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor having high responsiveness.SOLUTION: A linear motor 1 includes: magnet rows 3 each having a plurality of magnets 15 arranged in the x direction so that a magnetization direction is set orthogonal to a drive direction (x direction) and orientations of magnetic poles are reversed alternately; a coil assembly 5 having three coils 17 which are coaxially arranged in the x direction over a length of two of the plurality of magnets 15; and three wirings 23 for U, W and V phases (positive and negative of each phase are based on the orientation of current around the axis of the coil 17), which are connected to the three coils 17 in the arrangement order.

Description

  The present invention relates to a linear motor device and a linear motor.

  As a synchronous linear motor using three-phase AC power, one in which coils are coaxially arranged (laminated) in the driving direction (magnet arrangement direction) is known (for example, Patent Documents 1 and 2). In Patent Document 1, in the driving direction, the length of four magnets and the length of six coils are the same, and the six coils have U phase, -U phase, W phase, -W in the order of arrangement. Phase, V phase, and -V phase voltages are applied. Also, in Patent Document 2, the length of two magnets and the length of three coils are the same in the driving direction, and the three coils have voltages of U phase, V phase, and W phase in the order of arrangement. Is applied.

  In addition, according to the positive / negative of the phase of the electric power in this application mentioned later, the voltage applied in patent document 2 is specified from the moving direction of a coil as U phase, -V phase, and W phase. Patent Document 1 also describes applying the voltages of the U phase, V phase, W phase, U phase, V phase, and W phase with the winding directions of the six coils reversed from each other. However, the voltage is a U phase, a -V phase, a W phase, a U phase, a -V phase, and a W phase according to the sign of the power phase in the present application.

JP 2002-238240 A JP 2005-237081 A

  Synchronous linear motors have the advantage of a longer drive range than linear motors called voice coil motors, but have the disadvantage of low responsiveness. On the other hand, a high response may be required for the synchronous linear motor. For example, as a linear motor for wire bonding that requires high responsiveness, there is a desire to use a synchronous linear motor in order to extend the driving range.

  An object of the present invention is to provide a linear motor device and a linear motor with high responsiveness.

  The linear motor device of the present invention includes a magnet array having a plurality of magnets arranged in the drive direction so that the magnetization direction is orthogonal to the drive direction and the direction of the magnetic poles is alternately reversed, and the plurality A coil assembly including three coils coaxially arranged in the drive direction over the length of the two magnets adjacent to each other in the drive direction of the magnet in the drive direction; and On the other hand, the power supply apparatus supplies power of U phase, W phase and V phase (however, the positive and negative of each phase is based on the direction of the current around the axis of the coil) in the arrangement order.

  Preferably, an outer yoke that extends in the driving direction and is disposed on the opposite side of the coil of the magnet row, a center yoke that extends in the driving direction and is inserted through the coil assembly, and the magnet row of the magnet row, An end yoke connected to the outer yoke and the center yoke on the outer side in the driving direction and having a distance from the magnet row larger than the distance between the center yoke and the magnet row is further included.

  Preferably, the number of the plurality of magnets arranged is an odd number.

  Preferably, it further includes a nonmagnetic and conductive tubular member surrounding the center yoke and inserted through the coil assembly.

  The linear motor of the present invention includes a magnet array having a plurality of magnets arranged in the drive direction so that the magnetization direction is orthogonal to the drive direction and the direction of the magnetic poles is alternately reversed, and the plurality of magnets A coil assembly including three coils arranged coaxially in the drive direction over the length of two magnets, and a U-phase connected to the three coils in the arrangement order; And three wirings for W phase and V phase (however, the positive and negative of each phase is based on the direction of current around the axis of the coil).

  According to the present invention, the responsiveness can be increased.

The perspective view which shows the external appearance of the linear motor which concerns on embodiment of this invention. Sectional drawing in the II-II arrow direction of FIG. The figure which shows the structure of the electric power supply system of the linear motor apparatus which has the linear motor of FIG. Sectional drawing which shows the magnetic path | route in the linear motor of FIG. 5A and 5B are diagrams schematically showing magnetic flux densities in the linear motor of FIG. 1 and the linear motor of the comparative example. FIGS. 6A to 6C are schematic cross-sectional views for explaining the position and current direction of the linear motor of FIG. FIGS. 7A to 7C are schematic cross-sectional views for explaining the position and current direction of a linear motor of a comparative example. The perspective view which shows the external appearance of the modification of a linear motor.

  FIG. 1 is a perspective view of a linear motor 1 according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II in FIG.

  The linear motor 1 is driven with the x direction as a driving direction when three-phase AC power is supplied. The three-phase AC power is composed of U-phase, V-phase, and W-phase AC powers that are out of phase by 2π / 3. For example, if the alternating current is expressed by a sine function, the alternating currents of the U phase, V phase, and W phase are sin (ωt), sin (ωt−2π / 3), sin (ωt−4π / 3). ).

  The linear motor 1 includes two magnet rows 3 arranged along the x direction and a coil assembly 5 that can move in the x direction with respect to the two magnet rows 3. The linear motor 1 has an outer yoke 7, a center yoke portion 9, and an end yoke 11 so that a magnetic circuit is suitably formed, and an electric wire 13 for supplying power to the coil assembly 5 (FIG. 1). have.

  The magnet row 3 has a plurality of magnets 15 arranged in the x direction. As shown in FIG. 1, the plurality of magnets 15 are arranged so that the magnetization direction is the z direction (a direction orthogonal to the drive direction). The plurality of magnets 15 are arranged in the x direction so that the directions of the magnetic poles are alternately reversed. The two magnet rows 3 are arranged to face each other in the z direction. The plurality of magnets 15 in one magnet row 3 and the plurality of magnets 15 in the other magnet row 3 are opposed to the same type of magnetic poles. In the two magnet arrays 3, the number of magnets 15 is set to be equal to each other. Although the number of the magnets 15 in each magnet row | line | column 3 may be set suitably, for example, it is an odd number (7 in this embodiment).

  For example, the magnet 15 is formed in a plate shape (thin rectangular parallelepiped shape) in which the y direction (direction perpendicular to the driving direction and the magnetization direction) is the long direction, the x direction is the short direction, and the z direction is the thickness direction. Yes. In other words, the magnet 15 is formed so that the size in the y direction> the size in the x direction> the size in the z direction.

  The coil assembly 5 is disposed between the two magnet arrays 3. The coil assembly 5 includes a U-phase coil 17U, a W-phase coil 17W, and a V-phase coil 17V that are coaxially arranged in the x direction (hereinafter simply referred to as “coil 17”, which may not be distinguished from each other). is there.).

  The U-phase coil 17U, the W-phase coil 17W, and the V-phase coil 17V are supplied with U-phase, W-phase, and V-phase power of three-phase AC power when the coil assembly 5 moves to the positive side in the x direction. Are arranged in that order.

  The linear motor 1 can be driven in both directions in the x direction, and when the coil assembly 5 moves to the negative side in the x direction, the U-phase coil 17U and the W-phase are opposite to the above-described power supply mode. V-phase, W-phase, and U-phase power is supplied to the coil 17W and the V-phase coil 17V. In other words, in this application, when the U-phase, W-phase, and V-phase powers are supplied to the three coils 17 in the order of arrangement, the order of arrangement is from either side in the x direction. Also good. However, in the description of the present embodiment, it is assumed that the coil assembly 5 moves to the positive side in the x direction unless otherwise specified.

  The three coils 17 are formed in a size covering the length of two magnets 15 in the x direction. In other words, the ratio between the number of coils 17 and the number of magnets 15 arranged at a predetermined length in the x direction is 3: 2.

  Although not shown in particular, each coil 17 is formed by winding a wire having a conducting wire and an insulating film covering the conducting wire. In addition, in order to raise a space factor, it is preferable that a cross-section is a rectangular wire with a rectangular cross section, and the wire is wound in an aligned manner. The conducting wire is made of, for example, metal. The conducting wire is preferably formed of aluminum in order to reduce the weight of the coil assembly 5 that is generally a mover. The coating is made of, for example, a resin.

  The shape of the coil 17 is maintained by fixing adjacent portions of the wire to each other with an adhesive. The shape is, for example, substantially rectangular or oval when viewed in the axial direction (opening direction) of the coil 17 (FIG. 2). Moreover, the cross section orthogonal to the winding direction of the coil 17 is a rectangle, for example (refer FIG. 4). The coil 17 has a facing portion 17 a (FIG. 2) that extends in the y direction and faces the magnet array 3. For example, the coil 17 is formed so that the size in the y direction> the size in the z direction> the size in the x direction.

  The outer yoke 7 is disposed on the opposite side of the magnet assembly 3 from the coil assembly 5. The outer yoke 7 is formed of, for example, a magnetic material such as iron, and is formed in a rectangular flat plate shape whose thickness direction is the z direction. The outer yoke 7 has, for example, a width extending over the magnet row 3 in the x direction and the y direction, and the magnet row 3 is fixed to the main surface thereof by an adhesive or a bolt.

  The center yoke portion 9 extends in the x direction and is inserted through the coil assembly 5. The center yoke portion 9 has a center yoke 19 as a main body and a tubular member 21 surrounding the center yoke 19.

  The center yoke 19 is formed of a magnetic material such as iron, for example, and is slightly smaller than the cavity of the coil assembly 5 (in this embodiment, a rectangular flat plate with the z direction as the thickness direction). Is formed.

  The tubular member 21 is formed in a cylindrical shape similar to the outer shape of the center yoke 19 (in this embodiment, a cylindrical shape having a rectangular cross section), and covers substantially the entire center yoke 19. The tubular member 21 is made of a nonmagnetic and conductive material. Examples of such a material include copper, aluminum, and stainless steel. The tubular member 21 is formed, for example, by pressing a sheet metal.

  The end yoke 11 is disposed outside the magnet array 3 in the arrangement direction (x direction). The end yoke 11 is formed of a magnetic material such as iron, for example, and is formed in a rectangular flat plate shape having the x direction as the thickness direction. The flat area is, for example, an area that closes the gap between the end portions of the two outer yokes 7. The end yoke 11 is fixed in contact with the outer yoke 7 and the center yoke 19. The fixing is performed by, for example, a screw, solder, or an adhesive. The end yoke 11 also functions as a connecting member that fixes the two outer yokes 7 and the center yoke 19 to each other.

  A distance d2 between the end yoke 11 and the magnet row 3 is set longer than a distance d1 between the center yoke 19 and the magnet row 3. Preferably, the distance d2 is 1.2 times or more than the distance d1, and more preferably 1.5 times or more.

  The electric wires 13 correspond to the U-phase, W-phase, and V-phase of the three-phase AC power, and the U-phase wiring 23U, the W-phase wiring 23W, and the V-phase wiring 23V (hereinafter simply referred to as “wiring 23” are distinguished from each other). May not.) In addition, the electric wire 13 may contain the wiring corresponding to a neutral phase besides this. U-phase wiring 23U, W-phase wiring 23W and V-phase wiring 23V are connected to U-phase coil 17U, W-phase coil 17W and V-phase coil 17V, respectively. The wiring 23 includes, for example, a conductive wire and an insulating film that covers the conductive wire, although not particularly illustrated.

  In various organizations such as public offices, standards organizations, and companies, the phases and colors are defined by specifications or standards in order to identify the phases assigned to each wiring by the color of the coating. Therefore, in general, the wiring 23 can specify which phase of power is supplied even when no power is supplied. As a result, it is possible to specify which phase of the coil 17 is supplied with power even when the power is not supplied.

  FIG. 3 is a diagram illustrating a configuration of a power supply system of the linear motor device 31 having the linear motor 1.

  The linear motor device 31 includes the linear motor 1 and a power supply device 33 that supplies three-phase AC power to the linear motor 1. The three-phase AC power is supplied by, for example, Y connection.

  For example, when the winding direction of the coil 17 is reversed or the connection of the both ends of the wire rod of the coil 17 to the power supply device 33 is reversed, the direction of the current around the axis (around the x axis) in the coil 17 is reversed. It becomes the direction. That is, in the power supply device 33, although the positive / negative of the phase is not reversed, the positive / negative of the phase of the electric power is substantially reversed (the phase is shifted by 180 °) in the coil 17. .

  Therefore, in the present application, for convenience, the positive / negative of the U phase, the W phase, and the V phase is defined based on the direction of the current around the axis of the coil 17. For example, in the configuration in which U-phase, W-phase, and V-phase power is supplied to the U-phase coil 17U, the W-phase coil 17W, and the V-phase coil 17V, the winding directions of the three coils 17 are the same. When the phase of the wire is a specific phase (for example, 90 ° in each phase), the positive and negative of the start end (winding start) and the end (winding end) of the wire rod are the same. It is assumed that not only a typical configuration for outputting phase power but also other configurations in which the same current is realized in the three coils 17 are included.

  As an example, the winding direction of the W-phase coil 17W is reversed with respect to the above representative configuration, and the connection between both ends of the wire rod of the coil 17 and the power supply device 33 is not changed with respect to the above representative configuration, In the configuration in which the power supply device 33 outputs U-phase, -W-phase, and V-phase power, U-phase, W-phase, and V-phase power is supplied to the U-phase coil 17U, the W-phase coil 17W, and the V-phase coil 17V. Included in the configuration.

  In addition, since the initial phase of the power can be arbitrarily set, when the U-phase, W-phase, and V-phase power is supplied to the three coils 17 in the arrangement order, the three coils 17 are supplied. In this order, “W phase, V phase and U phase”, “V phase, U phase and W phase”, “−U phase, −W phase and −V phase”, “−W phase, −V phase” And -U phase "or" -V phase, -U phase and -W phase ".

  The operation of the linear motor 1 having the above configuration will be described.

  FIG. 4 is a cross-sectional view showing a magnetic path in the linear motor 1.

  The magnetic field lines coming out of the N pole of the magnet 15 (excluding the magnet 15 at the end of the magnet row 3) facing the N pole toward the center yoke 19 enter the center yoke 19 as shown by the arrow y1. It branches in both directions in the x direction along the yoke 19 and enters the south poles of the magnets 15 on both sides.

  Similarly, the magnetic field lines coming out of the north pole of the magnet 15 with the north pole facing the outer yoke 7 enter the outer yoke 7 and branch along the outer yoke 7 in both directions in the x direction, as indicated by the arrow y2. Then, it enters the south pole of the magnet 15 on both sides.

  The magnetic field lines coming out from the N pole of the magnet 15 at the end of the magnet row 3 enter the center yoke 19 and branch along the center yoke 19 in both directions in the x direction, as indicated by the arrow y3. One branched magnetic field line enters the outer yoke 7 via the end yoke 11 and enters the S pole of the original magnet 15. The other branched magnetic field line enters the south pole of the adjacent magnet 15 from the center yoke 19, similarly to the magnetic field lines of the other magnets 15.

  As described with reference to FIG. 1, since the distance d <b> 2 is longer than the distance d <b> 1, the magnetic lines of force of the magnet 15 at the end of the magnet row 3 do not directly go to the center yoke 19 but directly to the end yoke 11. It is suppressed that it goes.

  Although not shown in particular, when the magnet 15 at the end of the magnet row 3 is the magnet 15 that directs the N pole toward the center yoke 19, the magnetic field lines coming out of the N pole enter the outer yoke 7 and enter the outer yoke. 7 branches in both directions in the x direction. One branched magnetic field line enters the center yoke 19 via the end yoke 11 and enters the S pole of the original magnet 15. The other branched magnetic field line enters the south pole of the adjacent magnet 15 from the outer yoke 7 in the same manner as the magnetic field lines of the other magnet 15.

  The magnetic flux between the magnet 15 and the center yoke 19 intersects the facing portion 17a of the coil 17 in the z direction. Therefore, when a current flows in the y direction in the facing portion 17a, a force for driving the coil assembly 5 in the x direction with respect to the magnet array 3 is generated according to Fleming's left-hand rule. The coil assembly 5 moves the length of two magnets 15 during one cycle of AC power.

  FIG. 5A is a graph schematically showing the magnetic flux density in the z direction at the position of the facing portion 17a in the present embodiment, and FIG. 5B is a graph in the z direction at the position of the facing portion 17a in the comparative example. It is a graph which shows magnetic flux density typically.

5A and 5B, the horizontal axis indicates the position in the x direction by the arrangement of the magnets 15, and the vertical axis indicates the magnetic flux density B (Wb / m ² ) in the z direction. In the comparative example, the end yoke 11 is omitted from the linear motor 1 of the present embodiment.

  As shown in FIG. 5A, in the linear motor 1 of the present embodiment, the end yoke 11 is provided, so that the magnetic flux density is distributed in a well-balanced manner up to the position of the magnet 15 at the end of the magnet row 3. On the other hand, as shown in FIG. 5B, when there is no end yoke 11, the magnetic flux density is low at the position of the magnet 15 at the end of the magnet row 3.

  Therefore, in the linear motor 1 of the present embodiment, a uniform driving force is applied to the coil assembly 5 over a relatively wide range up to the end of the magnet array 3 or the vicinity of the end compared to the comparative example. Can do. In other words, in the vicinity of the end of the magnet row 3, a decrease in responsiveness due to a decrease in driving force is suppressed.

  In general, in a synchronous linear motor, a relatively large number of magnets are arranged, and the end of the magnet array is outside the driving range, thereby realizing a uniform driving force within the driving range. Therefore, the linear motor 1 of the present embodiment can also be understood as having a wide driving range while suppressing an increase in size.

  In general, the magnets 15 are in pairs, and an even number of magnets 15 are arranged (this case is also included in the present invention) to improve the balance of magnetic flux density. An odd number of 15 arrays is also realistic.

  6A to 6C are schematic cross-sectional views for explaining the position of the linear motor 1 and the direction of current.

  6A to 6C correspond to the case where the phase of the U phase is 0 °, 30 °, and 60 °. An arrow y <b> 11 attached to each magnet 15 indicates the direction of the magnetic flux that intersects the coil 17. Further, “+” attached to the coil 17 indicates that the direction of the current is the direction from the back of the page to the front, and “−” indicates that the direction of the current is the opposite. The number of “+” or “−” increases as the current increases (however, the current and the number are not proportional).

  As understood from these drawings, when the coil 17 is located between the magnets 15 (the U-phase coil 17U in FIG. 6A and the W-phase coil 17W in FIG. 6C), the current becomes zero. . The current increases as each coil 17 is located at the center of the magnet 15, and when the coil 17 is located at the center of the magnet 15, the current becomes maximum. Therefore, electric power is efficiently used for generating driving force.

  In the case where the phase is 60 ° to 360 °, the positions of the coil assembly 5 are shifted, and “+” and “−” in FIGS. 6A to 6C are reversed and / or , “+” And “−” are reversed, and are essentially the same as FIG. 6A to FIG. 6C.

  Fig.7 (a)-FIG.7 (c) are typical sectional drawings explaining the position and direction of an electric current of the linear motor of a comparative example.

  In the linear motor of the comparative example, similarly to Patent Document 1, the four lengths of the magnet 15 and the six lengths of the coils 17 are the same. Phase, -U phase, W phase, -W phase, V phase, and -V phase voltages are applied.

  In the comparative example, the current becomes relatively high when the coil 17 is positioned between the magnets 15 (-W phase coil 17-W in FIG. 7A, -V phase coil 17- in FIG. 7B). V, -V phase coil 17-V) of FIG.

  Thus, the linear motor 1 of this embodiment can use electric power efficiently for driving the linear motor. As a result, responsiveness is also improved.

(Examples and Comparative Examples)
In the coil assembly 5, the U-phase, W-phase, and V-phase voltages are applied to the three coils 17 in the order of arrangement, thereby reducing the mutual inductance between the coils 17. Responsiveness is improved.

  Therefore, an example of a simulation calculation result of mutual inductance between UV, VW, and WU is shown below. The calculation results are obtained when the U-phase, W-phase, and V-phase voltages are applied to the three coils 17 in the arrangement order (Example), and the U-phase, -V phase for the three coils 17 in the arrangement order. And a case where a W-phase voltage is applied (comparative example).

UV VW UW
Example 1 (no tubular member 21) 6.79 6.71 10.06
Example 2 (having a tubular member 21) 3.66 3.56 4.42
Comparative Example 1 (no tubular member 21) 18.20 18.11 10.06
Comparative Example 2 (having a tubular member 21) 5.94 5.95 4.42
The unit is mH.
The tubular member 21 is made of copper.

  In the above calculation results, the mutual inductance between UV and VW is about 1/3 in Example 1 compared to Comparative Example 1. The mutual inductance of the second embodiment is about half of the mutual inductance of the first embodiment. Thus, by applying the U-phase, W-phase, and V-phase voltages to the three coils 17 in the order of arrangement, and further by providing the tubular member 21, the mutual inductance is drastically reduced. .

  The present invention is not limited to the above embodiment, and may be implemented in various aspects.

  The linear motor of the present invention may be used for various applications. Further, either the magnet array or the coil assembly may be a stator or a mover.

  The number of magnet rows is not limited to two. One magnet row may be provided, and conversely, a magnet row may be further provided on the side (y direction in FIG. 1). All or part of the yoke may be omitted. For example, the end yoke may be omitted, and only the center yoke (or the center yoke portion including a tubular member) and the outer yoke may be used.

  The number of coils is not limited to three. For example, the coil assembly 205 may include six coils 17 as in the linear motor 201 shown in FIG. Further, the number of coils is not limited to a multiple of 3 as long as it is 3 or more.

  The tubular member is not limited to a sheet metal shape. For example, the tubular member may be a film formed by being deposited on the center yoke.

  DESCRIPTION OF SYMBOLS 1 ... Linear motor, 3 ... Magnet row, 5 ... Coil assembly, 15 ... Magnet, 17 ... Coil, 31 ... Linear motor apparatus, 33 ... Power supply device.

Claims (5)

A magnet array having a plurality of magnets arranged in the drive direction so that the magnetization direction is orthogonal to the drive direction and the direction of the magnetic poles is alternately reversed;
A coil assembly including three coils arranged coaxially in the drive direction over the length of the two magnets adjacent to each other in the drive direction of the plurality of magnets;
A power supply device for supplying electric power of U phase, W phase and V phase (the positive and negative of each phase is based on the direction of the current around the axis of the coil) in the arrangement order to the three coils; ,
A linear motor device. An outer yoke extending in the drive direction and disposed on the opposite side of the magnet array from the coil;
A center yoke extending in the drive direction and inserted through the coil assembly;
An end yoke connected to the outer yoke and the center yoke on the outer side in the driving direction of the magnet row, and having a distance from the magnet row larger than the distance between the center yoke and the magnet row,
A linear motor device further comprising: The linear motor device according to claim 2, wherein the number of the plurality of magnets arranged is an odd number. The linear motor device according to claim 2, further comprising a nonmagnetic and conductive tubular member that surrounds the center yoke and is inserted through the coil assembly. A magnet array having a plurality of magnets arranged in the drive direction so that the magnetization direction is orthogonal to the drive direction and the direction of the magnetic poles is alternately reversed;
A coil assembly including three coils arranged coaxially in the drive direction over the length of two of the plurality of magnets;
The three coils for U phase, W phase, and V phase (the positive and negative of each phase are based on the direction of current around the axis of the coil) connected to the three coils in the arrangement order. Wiring and
Linear motor having

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