JP2000289468A - Support structure for power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the occupant G caused by a head-on collision and prevent the drop of a power unit by providing a notch section on the rear side of the mount rubber fitting bracket of a rear mount, and making the notch section of the bracket plastically deformable in the shrinking direction by a prescribed forward load input or above. SOLUTION: At the time of a head-on collision, a power unit is displaced forward relatively to a vehicle body to absorb energy. A notch section 22b provided on the rear side of a rear mount bracket 22 is plastically deformed in the shrinking direction by a load input at the time of the head-on collision in particular, thus the rear mount bracket 22 is not ruptured after plastic deformation, and the power unit is not dropped from the vehicle body. If an engine is supported displaceably forward and the rear mount bracket 22 is made plastically deformable, the vehicle body G is large at the initial stage of the collision, however the vehicle body G at the later stage of the collision is low and continues long. The peak of occupant G arrives at the later stage of the collision when the vehicle body G is low, and this peak value can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for supporting a power unit having an engine and a transmission on a vehicle body of, for example, a cab-over type vehicle.

[0002]

2. Description of the Related Art In the case of a cab-over type vehicle, as shown in FIG. 1, a power unit 1 comprising an engine 2, a transmission 3, and a transfer 4 is located under the floor behind a crushable portion 5a of a vehicle body 5 at the time of a frontal collision. So,
The engine 2 is arranged vertically so as to be forward. The driving force of the transmission 3 is distributed to the front wheels 6 and the rear wheels 7 via the transfer 4. The engine 2 of the power unit 1 is supported on the vehicle body 5 by a front mount 8, and the transmission 3 or the transfer 4 is also supported on the vehicle body 5 by a rear mount 9.

When a vehicle having the above structure collides with a wall or the like from the front, the impact acts on the vehicle body 5, the power unit 1, the occupant M and the like. In this case, the deformation of the vehicle body 5 is almost completely absorbed by the crushable portion 5a, and therefore hardly affects the power unit 1. Therefore, conventionally, a method of firmly fixing the power unit 1 to the vehicle body 5 has been generally adopted.

[0004]

However, when the power unit 1 is firmly fixed to the vehicle body 5, the load (the vehicle body G) received by the vehicle body 5 and the load (the unit G) received by the power unit 1 at the time of a frontal collision are generated. And at the same time, even if the crushable portion 5a absorbs impact energy, the vehicle body G (including the unit G) becomes relatively high as shown in FIG. In general, there is a slight delay from the occurrence of the vehicle body G to the occurrence of the occupant G, but since the restraint of the seat belt starts during a large period of the vehicle G, the chest acceleration or the head acceleration (occupant G) is large, and the shock received by the occupant M is also large. In addition, in order to reduce the vehicle G, the power unit 1 may be dropped from the vehicle body 5 at the time of a frontal collision. However, there is a problem that oil leakage may occur due to breakage of a transmission case or the like due to the drop.

Accordingly, an object of the present invention is to reduce the occupant G by reducing the occupant G by supporting the power unit so that it can be displaced forward with respect to the vehicle body when an input such as a frontal collision occurs. It is an object of the present invention to provide a power unit support structure that can prevent the power unit from falling off the vehicle body.

[0006]

In order to achieve the above object, the present invention provides a power unit having an engine and a transmission, which is located rearward of a crushable portion of a vehicle body at the time of a frontal collision and in which the engine is located forward. The front mount allows the power unit to be displaced forward with respect to the vehicle body, with the front of the power unit supported by the vehicle body by the front mount and the rear of the power unit supported by the vehicle body by the rear mount. A notch is provided at the rear side of the mounting rubber mounting bracket of the rear mount, and the notch of the bracket can be plastically deformed in the direction of closing and closing by inputting a predetermined load or more forward. Provided is a power unit support structure characterized by the following.

When a vehicle collides with a wall or the like from the front, an impact load (the vehicle body G) acts on the vehicle body at that moment. At about the same time, an impact load (unit G) also acts on the power unit, but the front of the power unit is supported by a front mount so as to be displaceable forward, the rear is supported by a rear mount, and the rear mount is mounted. The bracket is formed to cause plastic deformation.
Therefore, the generation of the unit G is delayed as compared with the generation of the vehicle body G, and the peak of the unit G is suppressed due to the plastic deformation of the rear mount bracket. As a result, a large G is applied in the early stage of the collision as a whole of the vehicle, but in the late stage of the collision, the entire G is reduced and is maintained for a long time. The occurrence of the occupant G is later than the occurrence of the vehicle body G, but the occurrence of the occupant G in the latter half of the collision when the overall G has decreased, that is, the unit G decreases until the peak of the occupant G, reduces the shock applied to the occupant. can do.

According to the present invention, the rear mount bracket is configured so as to be plastically deformed but not broken. That is, a cutout portion is provided at the rear side of the rear mount bracket, and the cutout portion of the bracket can be plastically deformed in the direction of closing and closing when a predetermined load or more is input forward. Therefore, the rear mount bracket does not break even after being plastically deformed, and the power unit does not fall off. Since the power unit does not fall off, it is possible to prevent a problem that an oil leak occurs due to the breakage of the transmission case caused by the fall off.

In the present invention, the plastic deformation portion is provided on the rear mount bracket supporting the rear portion of the power unit, but the plastic deformation portion is not provided on the front mount bracket supporting the front portion (for example, the engine) of the power unit. The reason is that if a plastically deformable portion is provided on the front mount that supports the engine, the support rigidity that supports the heavy engine is reduced.

As a method of supporting the front portion of the power unit so as to be displaceable forward with respect to the vehicle body, for example, the axial direction of the mounting rubber of the front mount is set to the vehicle body front-rear direction, and the mounting rubber is moved in accordance with the forward displacement of the power unit. May be deformed in the thrust direction. Also,
The front part of the power unit may be slidably supported on the vehicle body.

The present invention is applicable to both two-wheel drive vehicles and four-wheel drive vehicles. In the case of a two-wheel drive vehicle, the rear mount supports the transmission, whereas in the case of a four-wheel drive vehicle, the rear mount may support either the transmission or the transfer. The number of rear mounts is not limited to one, but may be plural. In that case, a notch may be provided in each rear mount bracket. Further, the number of front mounts supporting the front part of the power unit is not limited to two, but may be three or more.

[0012]

FIG. 3 shows an example of a support structure for a power unit according to the present invention. This embodiment is applied to a cab-over type vehicle similar to FIG. The power unit 10 has an engine 11 at a front end thereof, an FR type transmission 12 at a center portion, and a transfer 13 at a rear end portion. The power unit 10 is disposed vertically below the crushable portion (see FIG. 1) of the vehicle body 15 and below the floor. Are located in Therefore, when a frontal collision occurs, impact energy from an obstacle is not directly transmitted to the power unit 10. Engine 11
Of the vehicle body 1 via two front mounts 14
5 is elastically supported. In addition, transfer 13
Is elastically supported by the vehicle body 15 via a rear mount 20.

As shown in FIG. 4, a front end of an arm 16 fixed to the engine 11 is fixed to an outer cylinder 14a, and an inner cylinder 14c is mounted at the center of the outer cylinder 14a via a mounting rubber 14b. It is provided integrally.
The inner cylinder 14c is supported by a bracket 18 by bolts 17 inserted therein. The bracket 18 is fastened to a vehicle body (for example, a side member) 15 with a bolt 19. Mount rubber 14b of front mount 14
(Bolt 17) is disposed in the front-rear direction of the vehicle body, and when a load on the engine 11 is applied to the front of the vehicle body,
The mount rubber 14b is deformed in the thrust direction, and the engine 11 can be displaced forward by a distance L with respect to the vehicle body 15.

As shown in FIGS. 5 and 6, the rear mount 20 includes a bracket 22 fastened by bolts 21 on the upper surface of the transfer 13.
The inner cylinder 20a of the rear mount 20 is supported by bolts 23 spanning the left and right arms 22a. Inner cylinder 2
The outer cylinder 20c is mounted on the outer circumference of the outer cylinder 20a via a mount rubber 20b.
Are integrally provided, and the outer cylinder 20 c is fixed to a vehicle body (for example, a cross member) 15. Rear mount 20
The axis (the bolt 23) of the mount rubber 20b is arranged in the vehicle width direction, so that when a load is applied to the transfer 13 toward the front of the vehicle body, the mount rubber 20b is deformed in the radial direction.

Arm 22a of rear mount bracket 22
A cutout portion 22b (see FIG. 5) is formed at the rear edge portion, and a plastic deformation portion 22c is formed at the front side of the cutout portion 22b. That is, when a load equal to or more than a predetermined value acts forward on the power unit 10 as in the case of a frontal collision, the plastically deformed portion 22c is notched as shown by the two-dot chain line in FIG.
2b has a function of plastically deforming in the direction of contraction, that is, the direction of compression, and absorbing impact energy. In addition, the plastic deformation part 2
2c has such a strength that it is not deformed by a vertical load or a front-rear load applied during normal running.

In this embodiment, a reinforcing member 24 (see FIG. 3) is provided between the engine 11 and the transfer 13. The reason for providing the reinforcing member 24 is that the power unit 10
Center of gravity Gu is offset in the vehicle width direction with respect to the vehicle body center CL, and when an input such as a frontal collision is applied, a counterclockwise moment acts on the transfer 13,
This is to prevent a problem such as breakage from occurring due to an excessive load acting on the transfer case. Another reason is that when the rear mount bracket 22 is plastically deformed during a frontal collision, the transfer 13
Is pulled rearward, and there is a possibility that a large load acts on the transfer 13 instantaneously.

Next, the operation of the support structure of the power unit 10 having the above configuration will be described. When the vehicle collides with a wall or the like from the front, the crushable portion of the vehicle body 15 is deformed and absorbs a part of the impact energy. Since the power unit 10 is located behind the crushable portion, the impact load from the wall is not directly transmitted to the power unit 10. The engine 11 is supported by a front mount 14 so as to be displaceable forward, the transfer 13 is supported by a rear mount 20, and the rear mount bracket 2
2 is plastically deformable forward. Therefore, the power unit 10 is displaced forward relative to the vehicle body 15 and absorbs energy. In particular, rear mount bracket 2
2 is plastically deformed in the closing direction by the load input at the time of a frontal collision, so that the rear mount bracket 22 does not break even after the plastic deformation, and the power unit 10 may fall off the vehicle body 15. Absent.

FIG. 7 shows a time change of the vehicle body G (including the unit G) and the occupant G at the time of a frontal collision. When the power unit is integrally fixed to the vehicle body, since the vehicle body G and the unit G are substantially synchronized as shown in FIG. 2, the peak of the vehicle body G is high, and the duration of the vehicle body G is high. Is relatively short. However, since the peak of the occupant G arrives before the body G lowers, the shock received by the occupant is large.
On the other hand, if the front mount 14 supports the engine 11 so that it can be displaced forward and the rear mount bracket 22 can be plastically deformed as in the present invention, as shown in FIG. However, since the power unit 10 is displaced forward with respect to the vehicle body 15 and absorbs energy by plastic deformation of the rear mount bracket 22, the vehicle body G in the late stage of the collision is low and lasts long. Since the peak of the occupant G arrives in the late collision of the vehicle body G, the peak value of the occupant G can be suppressed,
Shock experienced by occupants can be reduced.

[0019]

As apparent from the above description, according to the present invention, the front portion of the power unit is supported by the front mount so as to be displaceable forward with respect to the vehicle body.
The rear mounting rubber mounting bracket that supports the rear of the power unit is made plastically deformable, so when there is an input such as a frontal collision, the power unit is displaced forward with respect to the vehicle body and the rear mount bracket absorbs energy And the vehicle body G in the late stage of the collision
Lower and last longer. Therefore, the shock to the occupant can be reduced by adjusting the occupant G to the late collision period of the vehicle body G. In addition, the notch provided on the rear side of the rear mount bracket is plastically deformed in the closing direction by the load input at the time of a frontal collision, so the rear mount bracket does not break even after plastic deformation, and the power unit may fall off the vehicle body. Absent. Therefore, breakage of the transmission case due to falling off can be prevented, and oil leakage can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a cab-over type vehicle equipped with a power unit.

FIG. 2 is a diagram showing a time change of a vehicle body G and an occupant G in a conventional vehicle.

FIG. 3 is a plan view of a power unit support structure according to the present invention.

FIG. 4 is an enlarged sectional view of the front mount of FIG. 3;

FIG. 5 is a side view of the rear mount of FIG. 3;

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is a diagram showing a time change of the vehicle body G and the occupant G according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Power unit 11 Engine 12 Transmission 13 Transfer 14 Front mount 15 Body 20 Rear mount 22 Rear mount bracket 22b Notch 22c Plastic deformation part

Claims (1)

[Claims] A power unit having an engine and a transmission is disposed vertically behind a crushable portion of a vehicle body at the time of a frontal collision so that the engine is forward, and a front portion of the power unit is mounted by a front mount. In a vehicle that is supported on the vehicle body and the rear part of the power unit is supported on the vehicle body by a rear mount, the front mount supports the power unit so that the power unit can be displaced forward with respect to the vehicle body. A support structure for a power unit, wherein a cutout portion is provided at a rear side, and the cutout portion of the bracket can be plastically deformed in a closing and closing direction by a load input of a predetermined amount or more forward.