Power unit support structure

Abstract

This power unit support structure comprises: a dash panel that partitions a vehicle cabin and a power chamber positioned on the front side of the vehicle cabin in the vehicle front-rear direction; a power unit that includes a drive motor for vehicle travel disposed in the power chamber; a front-side mount for supporting the front part of the power unit on a vehicle body; and a pair of rear-side mounts for supporting the rear part of the power unit on the vehicle body. The pair of rear-side mounts comprises: an outer cylinder that extends in the vehicle width direction; and an inner cylinder that is supported on the inner surface side of the outer cylinder via an elastic member and has a shaft extending in the vehicle width direction.

Description

Power unit support structure

[0001] The present invention relates to a power unit support structure.

[0002] Patent Document 1 discloses the structure of a power unit suspended and supported on an upper cross member via a mounting device.

[0003] Japanese Patent No. 6620763

[0004] By the way, in the structure of Patent Document 1, there is a risk that the power unit and the rear dash panel will strongly interfere with each other during a frontal collision.

[0005] An object of the present invention is to provide a power unit support structure capable of suppressing interference between the power unit and the rear dash panel during a frontal collision.

[0006] The power unit support structure according to one aspect of the present invention includes a dash panel that partitions a passenger compartment and a power compartment located on the front side in the vehicle longitudinal direction of the passenger compartment, a power unit including a drive motor for vehicle travel disposed in the power compartment, a front mount that supports the front portion of the power unit on the vehicle body, and a pair of rear mounts that support the rear portion of the power unit on the vehicle body. The pair of rear mounts includes an outer cylinder extending in the vehicle width direction and an inner cylinder supported on the inner surface side of the outer cylinder via an elastic member and having a shaft extending in the vehicle width direction.

[0007] According to the above power unit support structure, interference between the power unit and the rear dash panel during a frontal collision can be suppressed.

[0008] FIG. 1 is a perspective view showing a power unit support structure according to an embodiment. FIG. 2 is a side view showing the power unit support structure. FIG. 3 is a front view showing the power unit support structure. FIG. 4A is a side view showing the power unit support structure before the input of a collision load. FIG.  4B is a side view showing the mode of deformation of the power unit support structure when a collision load is input. FIG. 5A is a side view showing the structure of the suspension before the input of a collision load. FIG. 5B is a side view showing the mode of deformation of the suspension structure when a collision load is input. FIG. 6 is a side view showing the power unit support structure.

[0009] The power unit support structure according to the embodiment will be described below with reference to the drawings. For the sake of explanation, the height direction of the power unit support structure or suspension member 3 in Figure 2-6 will be referred to as the vertical direction. In Figure 2, 4A-6, the left side in the left-right direction will be the front side in the vehicle's longitudinal direction, and the right side in the left-right direction will be the rear side in the vehicle's longitudinal direction. In Figure 3, the left side in the left-right direction will be the right side in the vehicle's width direction, and the right side in the left-right direction will be the left side in the vehicle's width direction. In the following description, the front, front side, rear, and rear side in the vehicle's longitudinal direction, the upper and lower sides in the vehicle's vertical direction, and the left and right sides in the vehicle's width direction will simply be referred to as front, front side, rear, rear side, upper, lower, left, and right, respectively. Furthermore, components having the same function as those already described will be denoted by the same reference numerals and their description will be omitted.

[0010] The power unit support structure includes a power unit 11 positioned in front of the dash panel D, a front mount 21 that supports the front part 11F of the power unit 11 to the vehicle body 1, and a pair of rear mounts 31, 31 that support the rear part 11B of the power unit 11 to the vehicle body 1. As illustrated in Figure 1-3, the power unit support structure according to this embodiment includes a pair of side members 2, 2, a suspension member 3, a power unit 11, a front mount 21, and rear mounts 31, 31.

[0011] The pair of side members 2, 2 are structural members of the vehicle body 1, located on the left and right sides. The pair of side members 2, 2 extend in the longitudinal direction of the vehicle. The pair of side members 2, 2 are located at the front of the vehicle and on the outside in the vehicle width direction of the power unit 11.

[0012] The structure of the left side member 2 of the vehicle body 1 will be described below. The structure of the right side member 2 is the same as the left side, so the description will be omitted. As illustrated in Figure 2, the side member 2 comprises a front part 2F and a rear part 2B. The front part 2F extends in the longitudinal direction of the vehicle. The rear part 2B is connected to the rear end of the front part 2F and has a larger vertical width than the front part 2F. As illustrated in Figure 2, the rear part 2B is provided with a circular through-hole 2H that penetrates in the vehicle width direction. The shape of the through-hole 2H is not limited to that shown above.

[0013] The suspension member 3 is a structural member of the frame that extends in the longitudinal direction and the vehicle width direction, and supports the suspension (not shown). As illustrated in Figure 1-3, the suspension member 3 is located below a pair of side members 2, 2. As illustrated in Figure 1, 5A, the suspension member 3 is composed of left and right side beams 3L, 3R extending in the longitudinal direction of the vehicle, a front cross beam 3F extending in the vehicle width direction, and a rear cross beam (not shown) extending in the vehicle width direction.

[0014] The structure of the left side beam 3L of the vehicle body 1 will be described below. The structure of the right side beam 3R is the same as the left side, so the description will be omitted. As illustrated in Figure 1, 5A, the suspension member 3 is a cross beam extending in the vehicle width direction and includes a front cross beam 3F provided at the front of the suspension member 3 and a rear cross beam provided at the rear of the suspension member 3. The side beam 3L extends forward from the left side of the rear cross beam in the vehicle width direction. The front end of the side beam 3L is connected to the left side of the front cross beam 3F which extends in the vehicle width direction. The suspension member 3 may also be connected to the upper side member 2 via brackets, arms, etc.

[0015] As illustrated in Figure 5A, the suspension member 3 is provided with a vulnerable portion 3A located behind the front crossbeam 3F. In the suspension member 3 according to this embodiment, a bead 3A1 is provided as the vulnerable portion 3A, which is concavely formed on the upper surface of the side beam 3L. Furthermore, a bead 3A2 is provided behind the bead 3A1, which is concavely formed on the lower surface of the side beam 3L. As illustrated in Figure 5A, the beads 3A1 and 3A2 are provided behind the front crossbeam 3F. The bead 3A1 is provided at a predetermined distance P1 behind the front crossbeam 3F in the vehicle's longitudinal direction. The bead 3A2 is provided at a predetermined distance P2 behind the bead 3A1 in the vehicle's longitudinal direction. Note that the position, shape, and number of vulnerable portions 3A are not limited to those described above. The function of the vulnerable portion 3A will be described later.

[0016] As illustrated in Figure 5A, the front crossbeam 3F is provided with an inclined surface 3F1. The inclined surface 3F1 is positioned at an angle with respect to the vehicle's longitudinal direction and extends in the vehicle's width direction. That is, the front part of the inclined surface 3F1 is positioned at an angle so that it is above the rear part of the inclined surface 3F1. In a side view of the vehicle, the inclined surface 3F1 is inclined to face the lower part of the front part 11F of the power unit 11.

[0017] As illustrated in Figure 6, the power unit 11 includes a drive motor 13 for driving the vehicle and a differential 14. As illustrated in Figure 6, the drive motor 13 is located at the rear 11B of the power unit 11 and has a pair of output shafts 13A, 13A extending in the vehicle width direction. The differential 14 is located in front of and below the drive motor 13, is connected to a drive shaft (not shown), and has a pair of drive shafts 14A, 14A extending in the vehicle width direction. As illustrated in Figure 6, in a side view of the vehicle, the output shaft 13A of the drive motor 13 and the drive shaft 14A of the differential 14 are located between the front mount 21 and the rear mount 31 in the vehicle's longitudinal direction. Note that the components constituting the power unit 11 and their arrangement are not limited to those described above.

[0018] As illustrated in Figures 1-3 and 1-6, the dash panel D is a partition plate that separates the motor room M, which is a power room located on the front side of the passenger compartment C in the vehicle's longitudinal direction, from the passenger compartment C, and is provided between the motor room M and the passenger compartment C in the vehicle's longitudinal direction. The power unit 11 according to this embodiment is located in the motor room M in front of the dash panel D. As illustrated in Figures 2, 4A and 1-6, a gap with a distance D1 in the vehicle's longitudinal direction is provided between the power unit 11 and the dash panel D. As illustrated in Figures 1-3 and 1-6, the above-mentioned side members 2, 2 extend from the dash panel D toward the front side in the vehicle's longitudinal direction within the motor room M.

[0019] The front mount 21 supports the power unit 11 on the suspension member 3. As illustrated in Figure 1-3, the front mount 21 is connected to the front crossbeam 3F provided on the suspension member 3. Also, as illustrated in Figures 3 and 6, the front portion 11F of the power unit 11 is supported by the front mount 21 via a fastening member 21B that extends perpendicularly to the inclined surface 3F1. Therefore, the front portion 11F of the power unit 11 is supported by the suspension member 3 by the front mount 21. The fastening member 21B according to this embodiment is a bolt (hereinafter referred to as bolt 21B). The bolt 21B is inserted through the front mount 21 in a position perpendicular to the inclined surface 3F1.

[0020] As illustrated in Figures 1 and 3, the casing 12 that constitutes the outer surface of the power unit 11 comprises a left portion 12L on the left side in the vehicle width direction and a right portion 12R on the right side. Therefore, the casing 12 is constructed by connecting the left portion 12L and the right portion 12R. The casing 12 encloses a drive motor 13 and a differential gear 14. As illustrated in Figures 1 and 3, the front mounts 21 according to this embodiment are provided on the left portion 12L and the right portion 12R, respectively (therefore, hereinafter referred to as front mounts 21, 21). In this case, the front crossbeam 3F is arranged to span at least a portion of each of the left portion 12L and the right portion 12R in the vehicle width direction. The front mounts 21, 21 are supported on the front crossbeam 3F by a pair of bolts 21B, 21B, respectively.

[0021] The structure of the left front mount 21 of the vehicle body 1 will be described below. The structure of the right front mount 21 is the same as the left side, so the description will be omitted. As illustrated in Figure 3, the front mount 21 consists of an outer cylinder 22, an inner cylinder 23, and an elastic member 24. The outer cylinder 22 is formed extending perpendicularly from the front part 11F of the power unit 11 to the inclined surface 3F1. The inner cylinder 23 is supported on the inner surface of the outer cylinder 22 via the elastic member 24. The inner cylinder 23 is also supported on the front cross beam 3F by a bolt 21B inserted inside the inner cylinder 23. As illustrated in Figure 6, in a side view of the vehicle, the insertion direction of the bolt 21B is inclined downwards towards the front with respect to the vehicle's longitudinal direction. That is, the inserted bolt 21B is inserted in a position where its front end is lower than its rear end. Also, the axial direction of the outer cylinder 22 and inner cylinder 23 (the direction in which the cylindrical shape extends) is parallel to the insertion direction of the bolt 21B. The configuration, arrangement, and number of the front mounts 21 are not limited to those described above.

[0022] The rear mounts 31, 31 support the power unit 11 on a pair of side members 2, 2, respectively. As illustrated in Figure 1-3, the rear mounts 31, 31 are provided on the outer side of the power unit 11 in the vehicle width direction, and support the power unit 11 on a pair of side members 2, 2, respectively. The outer side of the power unit 11 in the vehicle width direction is supported by the rear mounts 31, 31 via fastening members 31B, 31B that extend in the vehicle width direction and are inserted through the rear mounts 31, 31. The fastening members 31B, 31B in this embodiment are bolts (hereinafter referred to as bolts 31B, 31B). Also, as illustrated in Figure 3, the left part 12L and the right part 12R of the casing 12 are provided with bulging parts 12O, 12O that extend outward in the vehicle width direction, respectively. The rear mounts 31, 31 are fastened to the bulging portions 12O, 12O, respectively, by coaxially arranged bolts 31B, 31B.

[0023] The structure of the left rear mount 31 of the vehicle body 1 will be described below. The structure of the right rear mount 31 is the same as the left side, so the description will be omitted. As illustrated in Figure 3, the rear mount 31 consists of an outer cylinder 32, an inner cylinder 33, and an elastic member 34. The outer cylinder 32 is formed extending outward in the vehicle width direction from the bulge 12O of the rear part 11B of the power unit 11. The outer cylinder 32 is fitted into the through hole 2H. The inner cylinder 33 is supported on the inner surface side of the outer cylinder 32 via the elastic member 34. The inner cylinder 33 is also supported by the side member 2 by a bolt 31B inserted inside the inner cylinder 33. The axial direction in which the outer cylinder 32 and inner cylinder 33 extend is parallel to the insertion direction of the bolt 31B. The left and right bolts 31B, 31B are arranged coaxially along the vehicle width direction. Note that the configuration and arrangement of the rear mounts 31, 31 are not limited to the above.

[0024] The deformation and operation of the power unit support structure when a collision load is applied to the vehicle body 1 from the front of the vehicle due to a collision with an obstacle O illustrated in Figure 2, 4A-5B will be explained. When a load is applied to the vehicle body 1 from the front of the vehicle, the side beams 3L and 3R of the suspension member 3 bend and deform downward. In addition, the front cross beam 3F of the suspension member 3 is displaced rearward due to the load from the front of the vehicle. As a result, the front mounts 21, 21 supported by the front cross beam 3F are displaced rearward. Therefore, a force is applied to the front part 11F of the power unit 11, which is supported by the front mounts 21, 21, that tries to displace the power unit 11 rearward. On the other hand, the rear mounts 31, 31 are supported in the vehicle width direction by a pair of side members 2, 2 at a position rearward from the front mounts 21, 21. Therefore, a rotational moment is input to the power unit 11, with the front part 11F of the power unit 11, supported by the front mounts 21, 21, as the point of application, and the rear mounts 31, 31, supported in the vehicle width direction, as the axis of rotation, causing it to rotate backward. As a result, the power unit 11 can be rotated backward with the rear mounts 31, 31 as the axis of rotation. By rotating the power unit 11 backward, the stroke for absorbing loads from the front of the vehicle can be increased. Therefore, compared to a case where this power unit support structure is not present, more collision energy from the front of the vehicle can be absorbed. As a result, the amount of rearward displacement of the power unit 11 can be suppressed.

[0025] When a load is applied to the vehicle body 1 from the front of the vehicle, and the side beams 3L and 3R of the suspension member 3 bend and deform, the suspension member 3 can be deformed starting from the weak points 3A provided on the side beams 3L and 3R. For example, at the bead 3A1 portion provided on the upper surface of the side beams 3L and 3R, the suspension member 3 bends downward so that the bead 3A1 folds inward. At the bead 3A2 portion provided on the lower surface of the side beams 3L and 3R, the suspension member 3 bends upward so that the bead 3A2 folds inward. In this case, the suspension member 3 can be deformed into a roughly Z shape (see Figure 5B). That is, the suspension member 3 can be deformed into an appropriate shape, and the action of rotating the power unit 11 around the rear mounts 31, 31 can be appropriately generated.

[0026] The appropriate shape described above is, for example, a shape in which the suspension member 3 does not interfere with the power unit 11 and hinder its rotation when deformed. In this case, the distance between the beads 3A1 and 3A2 may be set to a predetermined distance P2 (see Figure 5A). This allows the deformed shape to be controlled so that the suspension member 3 is positioned below the rotational trajectory of the power unit 11 when it rotates. In other words, the suspension member 3 can be deformed in a way that does not hinder the rotation of the power unit 11. Furthermore, the distance between the front cross beam 3F and the bead 3A1 may be set to a predetermined distance P1 (see Figure 5A). This allows the deformed shape to be controlled so that the suspension member 3 is positioned below the rotational trajectory of the power unit 11, and the suspension member 3 can be deformed in a way that does not hinder the rotation of the power unit 11. In addition, the shape of the suspension member 3 can be controlled so that it does not interfere with the road surface when it is deformed.

[0027] As illustrated in Figure 4A, the power unit 11 according to this embodiment is positioned in front of the dash panel D with a gap of distance D1 between them. Furthermore, in a side view of the vehicle, the output shaft 13A and the drive shaft 14A of the power unit 11 according to this embodiment are offset in the longitudinal direction, so the length of the power unit 11 in the longitudinal direction of the vehicle is longer compared to a configuration in which the output shaft 13A and the drive shaft 14A are not offset in the longitudinal direction. Therefore, when positioning the power unit 11 within a predetermined range of the motor room M, the distance D1 between the power unit 11 and the dash panel D becomes relatively shorter compared to a configuration in which the output shaft 13A and the drive shaft 14A are not offset in the longitudinal direction. Consequently, in a configuration in which the output shaft 13A and the drive shaft 14A are offset in the longitudinal direction, a problem may arise in which it is not possible to secure sufficient stroke (rearward space for the power unit 11) to absorb collision energy during a frontal collision.

[0028] In contrast, in the power unit 11 according to this embodiment, when a load is input to the vehicle body 1 from the front of the vehicle, the front mount 21, which is relatively forward and downward of the rear mounts 31, 31, is displaced backward, and the power unit 11 can be rotated around the rear mounts 31, 31 as an axis. Therefore, the stroke for absorbing the load from the front of the vehicle can be expanded by the distance L by which the front surface of the power unit 11 substantially retracts before and after the rotation of the power unit 11 (see Figure 4B). In this case, when the power unit 11 rotates backward and becomes almost upright, the rotation trajectory of the casing 12 of the power unit 11 is configured not to interfere with (overlap with) the rear dash panel D (see Figure 4B). That is, the shape of the portion of the casing 12 rearward of the rear mounts 31, 31 is configured with a shape and dimensions that do not interfere with the dash panel D while the power unit 11 is rotating backward and becoming almost upright.

[0029] As illustrated in Figure 6, in the power unit support structure according to the embodiment, in a side view of the vehicle, the insertion direction S of the bolt 21B passes through the rear mount 31. In other words, in a side view of the vehicle, the extension of the central axis of the bolt 21B is configured to intersect with at least a part of the outer cylinder 32 of the rear mount 31. The extension of the central axis of the bolt 21B coincides with the insertion direction S of the bolt 21B. This allows the mount reaction force to be input to the driving torque in a direction substantially perpendicular to the insertion direction of the bolt 21B of the front mount 21. That is, it is possible to suppress the mount reaction force input to the front mount 21 from having an insertion direction component. This makes it possible to suppress the input of the insertion direction component of the mount reaction force to the elastic member 24 of the front mount 21, compared to the case where the mount reaction force is not substantially perpendicular to the insertion direction of the bolt 21B of the front mount 21, and to suppress the application of local stress to the elastic member 24.

[0030] As illustrated in Figure 6, in the power unit support structure according to the embodiment, in a side view of the vehicle, the insertion direction S of the bolt 21B passes near the output shaft 13A and the drive shaft 14A. In other words, in a side view of the vehicle, the straight line S (insertion direction S of the bolt 21B) passing through at least a part of the outer cylinder 22 of the front mount 21 and at least a part of the outer cylinder 32 of the rear mount 31 is configured to intersect the output shaft 13A and the drive shaft 14A. The straight line S may also pass through the lower part of the outer cylinder 22 of the front mount 21 and the upper part of the outer cylinder 32 of the rear mount 31 (straight line S1 illustrated in Figure 6). The straight line S may also pass through the lower part of the outer cylinder 22 of the front mount 21 and the lower part of the outer cylinder 32 of the rear mount 31 (straight line S2 illustrated in Figure 6). The straight line S may also pass through the upper part of the outer cylinder 22 of the front mount 21 and the upper part of the outer cylinder 32 of the rear mount 31 (straight line S3 illustrated in Figure 6). The straight line S may pass over the upper part of the outer cylinder 22 of the front mount 21 and the lower part of the outer cylinder 32 of the rear mount 31 (straight line S4 as illustrated in Figure 6). With the above configuration, the elastic centers of the elastic axes of the front mount 21 and the rear mounts 31, 31 can be brought closer to the center of gravity of the power unit 11. This makes it possible to suppress the generation of coupled vibration modes caused by the rotational (torsional) component and translational component during vibration of the power unit 11.

[0031] (1) The power unit support structure according to the embodiment comprises a dash panel D that separates a passenger compartment C from a motor room M, which is a power room located on the front side of the passenger compartment C in the vehicle's longitudinal direction; a power unit 11 including a drive motor 13 for vehicle driving arranged in the motor room M; a front mount 21 that supports the front part 11F of the power unit 11 to the vehicle body 1; and a pair of rear mounts 31, 31 that support the rear part 11B of the power unit 11 to the vehicle body. The pair of rear mounts 31, 31 comprises an outer cylinder 32, 32 extending in the vehicle width direction, and an inner cylinder 33, 33 that is supported on the inner surface side of the outer cylinder 32, 32 via elastic members 34, 34 and has an axis extending in the vehicle width direction.

[0032] With the above configuration, when a load is applied to the vehicle body 1 from the front of the vehicle, the front mount 21, which is relatively in front of the rear mounts 31, 31, is displaced rearward, and a force is applied to the front part 11F of the power unit 11, which is supported by the front mount 21, that tends to displace the power unit 11 rearward. On the other hand, the rear mounts 31, 31 are supported on the vehicle body 1 at a position rearward from the front mount 21 and have an axis parallel to the vehicle width direction. Therefore, a rotational moment is applied to the power unit 11, with the front part 11F of the power unit 11 supported by the front mount 21 as the point of application and the rear mounts 31, 31, which are supported in the vehicle width direction, as the axis of rotation, causing it to rotate rearward. As a result, the power unit 11 can be rotated rearward with the rear mounts 31, 31 as the axis of rotation. By rotating the power unit 11 rearward, the stroke for absorbing the load from the front of the vehicle can be increased. Therefore, the amount of rearward displacement of the power unit 11 can be suppressed. In other words, with the above configuration, more collision energy from the front of the vehicle can be absorbed compared to a configuration without the power unit support structure. Therefore, compared to a configuration without the power unit support structure, the amount of rearward displacement of the power unit 11 can be suppressed. This suppresses interference between the power unit 11 and the rear dash panel D, and prevents loads from being applied to the dash panel D from the front of the vehicle.

[0033] (2) In this embodiment, the pair of rear mounts 31, 31 are installed on side members 2, 2 that extend from the dash panel D toward the front in the vehicle longitudinal direction in the motor room M, and the front mount 21 is installed on a suspension member 3 that extends toward the vehicle longitudinal direction below the side members 2, 2. With this configuration, since the front mount 21 and the rear mounts 31, 31 are installed on separate members of the vehicle body 1, it becomes easy to control the movement mode of the power unit 11 (for example, displacement amount, displacement direction, rotation direction, etc.) when a load is input to the vehicle body 1 from the front of the vehicle.

[0034] (3) Furthermore, in this embodiment, the suspension member 3 has a weak point 3A located behind the installation position of the front mount 21. This makes it easier to control the bending mode of the suspension member 3 (e.g., displacement amount, displacement direction, displacement shape, etc.) when a load is applied to the vehicle body 1 from the front of the vehicle.

[0035] The embodiments described above are merely illustrative examples provided to facilitate understanding of the invention. The technical scope of the invention is not limited to the specific technical matters disclosed in the embodiments above, but also includes various modifications, changes, and alternative technologies that can be easily derived therefrom.

[0036] 1. Body 2,2. Side members 3. Suspension members 3A. Weak points 11. Power unit 11B. Rear 11F. Front 13. Drive motor 21. Front mount 31,31. Rear mount 32,32. Outer cylinder 33,33. Inner cylinder 34,34. Elastic members C. Passenger compartment D. Dash panel M. Motor room (power room)

Claims

1. A power unit support structure comprising: a dash panel that separates a passenger compartment from a power compartment located on the front side of the passenger compartment in the vehicle's longitudinal direction; a power unit including a drive motor for vehicle propulsion located in the power compartment; a front mount that supports the front of the power unit to the vehicle body; and a pair of rear mounts that support the rear of the power unit to the vehicle body, wherein the pair of rear mounts comprises an outer cylinder extending in the vehicle width direction and an inner cylinder having an axis extending in the vehicle width direction and supported on the inner surface side of the outer cylinder via an elastic member.

2. The power unit support structure according to claim 1, wherein the pair of rear mounts are installed on side members extending forward in the vehicle longitudinal direction from the dash panel in the power chamber, and the front mounts are installed on suspension members extending in the vehicle longitudinal direction below the side members.

3. The power unit support structure according to claim 1 or 2, wherein the suspension member has a weak portion located rearward from the installation position of the front mount.

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