JPH11278063A - Power unit support structure of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce idle primary and secondary vibration only by devising setting of inclination of an engine mount. SOLUTION: A specified axis J1 connecting a troque roll axis βand a crank axis α is specified and a roll vibration input position around the torque roll axis β to the engine mount 21 is shown by a mark (d) within a specified flat surface H1 orthogonal with the crank axis α at a part of the engine mount 21. The left and right engine mounts 21 are inclined to the inward side by θ, and their elastic central lines (r) cross with each other (intersection (b)) on the specified axis J1. The intersection (b) is positioned on the opposite side of the crank axis α within the specified flat surface H1. A distance L1 between the intersection (b) and the torque roll axis β (a) is made equal to a distance L2 from the torque roll axis ' (a) to the input position (d) in length in the direction of the specified axis J1 within the specified flat surface H1. Idle primary and secondary vibration is reduced by interference work of lateral vibration working on the engine mount 21 caused by roll vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a power unit support structure for a motor vehicle.

[0002]

2. Description of the Related Art In order to support a power unit in which an engine and a transmission are vertically arranged in the longitudinal direction of a vehicle body, a pair of right and left engine mounts for supporting the power unit on the vehicle body at an engine portion, and the power unit at a transmission portion. There is one that uses a total of three mounts, including one mission mount that is supported. For example,
As is often seen in 1-box cars and 1.5-box cars with shortened front nose, the weight of the power unit is supported from below by a pair of left and right engine mounts, and the power unit is suspended and supported from above by a mission mount. That is being done.

[0003] A pair of left and right engine mounts are usually inclined so that their elastic center lines intersect each other. In a predetermined plane orthogonal to the crankshaft at the engine mount position, the intersection of the elastic center lines is the power unit. It is set to be located on the torque roll axis. As a result, the roll vibration of the power unit about the torque roll axis acts only in the direction of the elastic center line of the engine mount, so that the engine mount is uncoupled (due to the roll vibration, No vibration is generated in the direction crossing the elastic center line).

[0004]

By the way, among the vibrations of the engine, vibrations in the vicinity of 4 to 6 Hz may be a problem, which is called so-called idle 1/2 vibration. For example, in a diesel engine having a fuel injection pump, in particular, a mechanical fuel injection pump, idling １ ／ secondary vibration increases due to a difference in fuel injection amount for each cylinder. In order to reduce the idle secondary vibration, it is conceivable to increase the number of mounts or improve the accuracy of the fuel injection pump, but in any case, the cost is considerably increased.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power unit support structure for an automobile capable of reducing idle half vibration without increasing the cost. To provide.

[0006]

In order to achieve the above-mentioned object, the present invention adopts the following solution. That is, in a power unit support structure in which an engine and a transmission are vertically arranged in the vehicle longitudinal direction as described in claim 1 of the claims, the engine is interposed as a mount for supporting the power unit on the vehicle body. A predetermined shaft having a pair of left and right engine mounts disposed and including an elastic member, and connecting a torque roll axis of the power unit and a crankshaft in a first predetermined plane orthogonal to a crankshaft of the engine at the engine mount position; The center of elasticity of the pair of left and right engine mounts is set to intersect on the line and on the opposite side of the crankshaft with respect to the torque roll axis, and on the predetermined axis, the pair of left and right elastic centers The first distance between the intersection of the lines and the torque roll axis is the torque. A second distance between said engine mount and roll axis is set to be substantially equal, it is so.

According to the above method, since the intersection of the elastic center lines of the pair of right and left engine mounts is located at a position deviated from the torque roll axis, lateral vibration (yawing vibration) is generated due to roll vibration. The yaw vibration reduces (cancels) idle 1/2 vibration. Preferred embodiments on the premise of the above solution are as described in claim 2 and the following claims.

[0008]

According to the first aspect, the idle secondary vibration can be reduced without increasing the cost by a very simple method of setting the inclination direction of the engine mount to a predetermined one. it can. Further, the magnitude of the lateral vibration (lateral force) input to the pair of left and right engine mounts due to the roll vibration is set to be substantially the same for each of the left and right engine mounts, and a large load is applied to only one of the engine mounts. Can be prevented.

According to the second aspect, it is preferable to average the load on the engine mount as much as possible. Claim 3
According to the above, the transmission mount is positioned almost in the vicinity of the center of the swing motion of the power unit in which the roll vibration around the torque roll axis and the lateral vibration caused by the roll vibration are combined, and an unreasonable load is imposed on the transmission mount. This is preferable in order not to apply the pressure.

According to claim 4, when the engine is considerably heavier than the engine and the transmission constituting the power unit, and the center of gravity of the power unit is closer to the engine in the direction of the crankshaft, each mount is used. This is preferable in that the reaction force of the vibration is almost uniformly received. According to the fifth aspect, as seen in a 1-box car, a 1.5-box car, or the like, the present invention is suitable for a case where the vehicle unit floor is located at a considerably high position and the power unit is arranged below the floor. According to the sixth aspect, it is possible to reduce idle secondary vibration which is a problem particularly in a diesel engine.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, an automobile 1 is a one-box car having an extremely short front nose. A front seat including a driver's seat is indicated by reference numeral 2 and a rear seat is indicated by reference numeral 3. 2, 3 (that is, the passenger compartment floor) are set at a considerably high position. A power unit P is arranged at a position lower than the front seat 2 at the front of the vehicle body. The power unit P includes an engine 11 and a transmission 12 behind the engine 11, and a clutch or a torque converter 13 is interposed between the engine 11 and the transmission 12 according to the type of the transmission 12. Each member 11-13
Are connected to each other to form one block body having high rigidity. As described above, at least the rear wheels 4 are driven by the power unit P in which the engine 11 and the transmission 12 are vertically arranged in the vehicle front-rear direction, but a four-wheel drive vehicle in which the front wheels 5 are also driven may be used. .
In the embodiment, the engine 11 is, in particular, the idle 1
For example, a four-cylinder in-line diesel engine provided with a mechanical fuel injection pump in which / secondary vibration is a problem.

Details of the power unit P are shown in FIGS. First, a pair of right and left engine mounts 2 provided on the side wall of the engine 11
It is supported by the vehicle body via 1L and 21R. In the following description, when there is no need to distinguish between left and right, only 21 may be used as a code indicating an engine mount. The rear of the power unit P is
Is supported by the vehicle body via one transmission mount 22 provided on the upper wall portion of the vehicle. Thus, the power unit P is supported by the vehicle body by the three mounts 21L, 21R, and 22 in total. The engine mount 21 is set to support the load of the power unit P from below, and the mission mount suspends and supports the power unit P from above.

The pair of right and left engine mounts 21 are substantially symmetrical, and basically include an engine side mounting member 31 fixed to the engine 11 and an engine side mounting member 31.
And a vehicle-body-side mounting member 32 fixed to the vehicle body (a sub-frame fixed to the vehicle body) and interposed between the mounting members 31 and 32.
And an elastic member 33 fixed to the The transmission mount 22 has an elastic member 41 interposed between an inner cylinder and an outer cylinder extending in the left-right direction, as will be described in detail later. A support shaft 42 inserted through the inner cylinder portion is connected to the vehicle body. You. Further, the mounting bracket 43 integrated with the outer cylinder is connected to the transmission 12 at two places in front and rear.

The left and right engine mounts 21L, 21R,
In particular, the elastic center line of the elastic member 33 will be described in detail below. First, the crank axis of the engine 11 is denoted by a symbol α.
And the torque roll axis of the power unit P is denoted by β
, And the center of gravity of the power unit P is indicated by a symbol G. The torque roll axis β passes through the center of gravity G, is located at a position higher than the crankshaft α (the cylinder head side of the engine 11) at the front of the power unit P, and gradually approaches the crankshaft line α toward the rear. And is inclined backward and downward with respect to the crank axis α.

The respective elastic center lines of the engine mounts 21L and 21R are indicated by a symbol r. Among the planes orthogonal to the crank axis (crank axis) α, a plane passing through the engine mount 21, that is, the elastic center line r is a first predetermined plane H.
It is set to 1. FIG. 3 is a cross-sectional view of the engine mount 21 taken along a first predetermined plane H1. Further, the first predetermined plane H1 extends in a direction perpendicular to the plane of FIG.
And the first predetermined axis J1.

A point at which the torque roll axis β intersects the first predetermined plane H1 is indicated by a symbol a, and a point at which the crank axis α intersects is indicated by an symbol o. Torque roll axis β
The axis extending in the up-down direction connecting the (intersection a) and the crank axis α (intersection o) is the first predetermined axis J1. Also,
Engine-side mounting member 31 of engine mount 21
The center of the mounting position with respect to the engine 11, that is, the input position to the elastic member 33 of the roll vibration and the lateral vibration described later is
The height position of the input position d is indicated by reference numeral d, and in the embodiment, coincides with the crankshaft height position.

Each elastic center line r in the engine mount 21 is within the first predetermined plane H1, and is gradually inclined toward the engine 11 as it goes upward.
The point of intersection between the elastic center lines r of the book is indicated by the symbol b. The intersection point b of each elastic center line r is located on the first predetermined axis J1. This intersection b is located on the opposite side of the crank axis α (intersection o) with respect to the torque roll axis β (intersection a). Now, assuming that the distance between the intersection and b and a is L1 and the distance between the intersection a and o is L2 on the first predetermined axis J1, L1 and L2 are set to be substantially equal (implementation). In the embodiment, L1 and L2 are completely set to be equal).

In the above setting, the engine 11
The roll vibration generated by the operation of (1) is a vibration around the torque roll axis β. Since the intersection point b is offset with respect to the torque roll axis β, lateral vibrations (lateral forces) in directions opposite to each other occur at the intersection point b and the input position d due to the roll vibration. Since the lateral vibration sets the distances L1 and L2 to be substantially equal, the lateral vibration acts on the left and right engine mounts 21L and 21R with substantially the same magnitude, and the lateral vibration can be received in a well-balanced manner. become.

The above-mentioned lateral vibration reduces idle half vibration. That is, in the conventional example in which the intersection b of the left and right elastic center lines r is set on the torque roll axis β, as shown by the broken line in FIG. It gets bigger.
On the other hand, according to the present invention, as shown by the solid line in FIG. 4, the idle secondary vibration is greatly reduced.

Now, assuming that the inward inclination angle of the elastic center line r is θ (see FIG. 3), it is confirmed that the smaller the θ, the greater the degree of reduction of the idle half-secondary vibration. Was. On the other hand, it was confirmed that the idle secondary vibration increases as θ decreases, that is, as the intersection b is set farther from the torque roll axis β. Since the idle secondary vibration is originally quite small, the idle half
What is necessary is just to set θ (the position of the intersection b) in a range where the secondary vibration is sufficiently reduced and the secondary idle vibration is not a problem.
As described above, the setting is made so that the lateral vibration acts on the left and right engine mounts 21L and 21R substantially averagely while suppressing both the idle half-secondary vibration and the idle secondary vibration to a satisfactory level range. In consideration of the above, the distances L1 and L2 are set to be substantially equal.

The center position of the transmission mount 22, that is, the position of the support shaft 42, is set as follows so that the reaction force around the torque roll axis β is substantially equal between the engine mount 21 and the transmission mount 22. I have. That is, a plane passing through the transmission mount 22 (support shaft 42) among planes perpendicular to the crank axis α is defined as a second predetermined plane H2, and the support shaft 42 and the torque roll shaft β are set within the second predetermined plane H2. (In the embodiment, since the transmission mount 22 is set at an intermediate position between the pair of left and right engine mounts 21, the second predetermined axis J2 is the second predetermined axis J2 in FIG. 3. 1 overlaps with the predetermined axis J1). On this second predetermined axis J2, the distance HM between the support shaft 42 and the torque roll shaft β
Is larger than the distance L2 between the intersections a and d (o). This is a setting because the weight of the engine 11 is considerably heavy, and the center of gravity of the power unit P comes to a position which is considerably offset to the engine 11 side.

The height position of the mission mount 22 can be set as follows, different from the embodiment. That is, in FIG. 2, the transmission mount 22 (the support shaft 42) can be set to be located on an axis passing through the intersection point a and parallel to the crank axis α. According to such a setting, the center position of the swing motion of the power unit P when the roll vibration about the torque roll axis β and the lateral vibration generated due to the roll vibration are combined is substantially equal to the transmission mount. 22, which is preferable in preventing or reducing the excessive bending force or twisting force acting on the mission mount 22.

Next, an example of the transmission mount 22 will be described in detail with reference to FIG. As described above, the transmission mount 22 is provided with the inner cylinder 45 extending in the left-right direction.
And an outer cylinder 46, and an elastic member 41 such as rubber is interposed between the two cylinders 45 and 46. The elastic member 41 includes the inner cylinder 4
5 is provided at each of the upper and lower positions with an indentation portion (void portion) 41a extending substantially horizontally, whereby the rigidity in the front-rear direction is high and the elastic member is set to be sufficiently elastically deformable in the vertical direction. .

While the support shaft 42 is inserted into the inner cylinder 45,
A vehicle body side mounting bracket 47 is fixed to the vehicle body side. The vehicle body-side mounting bracket 47 has a pair of left and right support legs 47a, and each end of the support shaft 41 is fitted and held in a support hole 47b formed in the support leg 47a.

A pair of left and right transmission-side mounting brackets 43 are integrated with the outer cylinder 46 by welding or the like. That is, in a state where the outer cylinder 46 is fitted into the holding holes 43a formed in the pair of mounting brackets 43,
And 46 are fixed. A pair of mounting brackets 43
Has a pair of front and rear mounting legs 50. An insertion hole 51 is formed in the pair of mounting legs 50, and a pair of left and right legs 5 is formed.
In a state where the connecting portion 12a provided on the transmission 12 is positioned between the zero, the leg portion 50 and the connecting portion 12a are connected by the connecting bolt 52 inserted into the insertion hole 51. A nut 53 is welded to one leg 50 in advance, and the connection bolt 52 is screwed to the nut 53.

Although the embodiment has been described above, the transmission mount 22 may be provided as a pair of left and right transmissions. Further, the mission mount 22 is not limited to the one that suspends and supports the power unit P.
May be supported from below. Of course, the engine 11 can be applied not only to a diesel engine but also to an engine of another combustion system such as a gasoline engine.
The purpose of the present invention is not limited to what is explicitly specified, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

[Brief description of the drawings]

FIG. 1 is a simplified side view showing an example of an automobile to which the present invention is applied.

FIG. 2 is a side view of a power unit to which the present invention is applied.

FIG. 3 is a front view of the power unit, showing the engine mount in section at a predetermined plane H1 (axis J1) in FIG. 2;

FIG. 4 is a diagram schematically showing the effect of the present invention.

FIG. 5 is an overall side view showing an example of a mission mount.

FIG. 6 is a perspective view showing a vehicle body-side mounting bracket of the mission mount.

FIG. 7 is a cross-sectional plan view of the mission mount, excluding a vehicle body-side mounting bracket.

FIG. 8 is a side sectional view of the mission mount, excluding a vehicle body-side mounting bracket.

[Explanation of symbols]

 1: automobile 11: engine 12: mission 21 (21L, 21R): engine mount 22: transmission mount 31: engine side mounting member 32: body side mounting member 33: elastic member 41: elastic member 42: support shaft P: power unit α : Crank axis β: Torque roll axis γ: Elastic center line of engine mount a: Intersection between first predetermined plane and torque roll axis b: Intersection of elastic center line o: Intersection with crank axis d: Input to engine mount Position H1: First predetermined plane H2: Second predetermined plane J1: First predetermined axis J2: Second predetermined axis L1, L2, HM: Distance

Claims (6)

[Claims] 1. A power unit support structure in which an engine and a transmission are vertically arranged in a vehicle longitudinal direction, wherein a mount for supporting the power unit on a vehicle body is provided.
A pair of left and right engine mounts including an elastic member and arranged between the engine, and a torque roll axis and a crankshaft of the power unit in a first predetermined plane orthogonal to a crankshaft of the engine at the engine mount position; On a predetermined axis connecting the two, and on the opposite side to the crankshaft with respect to the torque roll shaft, the elastic center lines of the pair of left and right engine mounts are set to intersect, and on the predetermined axis, A first distance between an intersection of a pair of left and right elastic center lines and the torque roll axis is set to be substantially equal to a second distance between the torque roll axis and the engine mount. A power unit support structure for an automobile. 2. The mount according to claim 1, wherein the mount unit supports the power unit on a vehicle body.
A mission mount including an elastic member is provided to support the transmission on the vehicle body, and the power unit is set to be supported by the vehicle body by a total of three mounts. A third distance between the transmission mount and the torque roll shaft in a second predetermined plane orthogonal to the crankshaft at the transmission mount position so as to substantially equally act on the engine mount and the transmission mount. A power unit support structure for an automobile, wherein the power unit support structure is set. 3. The system according to claim 1, wherein the power unit is mounted on a vehicle body as a mount.
A mission mount is provided which suspends and supports the mission on the vehicle body and includes an elastic member. The power unit is supported by the vehicle body by a total of three mounts of the mission mount and the pair of left and right engine mounts. When the height position of the torque roll shaft in the first predetermined plane is a predetermined height position, the transmission mount is positioned on an axis parallel to the crankshaft passing near the predetermined height position. A power unit support structure for an automobile. 4. The mount according to claim 1, wherein the mount unit supports the power unit on a vehicle body.
A mission mount is provided which suspends and supports the mission on the vehicle body and includes an elastic member. The power unit is supported by the vehicle body by a total of three mounts of the mission mount and the pair of left and right engine mounts. When a plane perpendicular to the crankshaft at the transmission mount position is a second predetermined plane, the distance between the torque roll axis and the engine mount in the first predetermined plane in the predetermined axis direction is larger than the distance between the torque roll axis and the engine mount. A power unit support structure for an automobile, wherein a distance between the torque roll shaft and the transmission mount in the second plane is set to be larger. 5. The mount according to claim 1, wherein the mount unit supports the power unit on a vehicle body.
A mission mount including an elastic member is provided while supporting the mission on the vehicle body, and the power unit is set to be supported on the vehicle body by a total of three mounts of the mission mount and the pair of left and right engine mounts, The pair of left and right engine mounts is of a downward supporting type so as to receive the load of the power unit from above, and the transmission mount is disposed at a substantially middle position on the left and right of the pair of right and left engine mounts to reduce the load of the power unit. A power unit support structure for an automobile, wherein the structure is a suspension type that receives from below. 6. A power unit supporting structure for an automobile according to claim 1, wherein said engine is a diesel engine.