JP2003094956A - Front body structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance absorbing performance of collision load by a front frame with simple structure without increasing the total length of a vehicle body, the number of parts and weight. SOLUTION: An engine body is tilted backward to exhaust backward, so that the center of gravity G of the engine body 17 is moved to the rear part of the vehicle body. An axial crush zone Z3 between the tip of the front frame 12 and an engine mounting bracket 20 disposed on or near the inertia S of axle passing the center of gravity G, and fixed to the front frame 12, can be substantially increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front vehicle body structure for a vehicle, in which a front frame has an improved performance of absorbing a collision load.

[0002]

[Prior Art] Front Engine / Front Drive
(FF) A so-called horizontal power unit, which is widely used in cars and has a power unit that is a combination of an in-line engine body and a transmission and is horizontally installed in an engine room, is a vehicle body for absorbing energy in a collision. As a structure, the front frame is a member that can most efficiently absorb energy.

When an impact load is to be absorbed on one side in front of the vehicle at the time of an offset collision, the structure is arranged behind the toe board supporting the front frame in a structure in which the front frame alone cannot secure a sufficient amount of energy absorption as in a light vehicle. The reaction force support members that are present must also be used to absorb energy.

However, the reaction force support member has a low collision energy absorption efficiency (energy amount / weight) in the deformation mode with respect to axial crushing as in the front frame.

Therefore, if the front frame can efficiently absorb the collision load, the amount of the collision load absorbed by the reaction force supporting member can be reduced, and the weight of the reaction force supporting member can be reduced accordingly. The weight of the entire vehicle body can be reduced.

For example, as shown in FIG. 6, in a structure in which a power unit is fixed via an engine mount bracket 2 to a front frame 1 arranged on both sides of the vehicle body in a state of extending in the vehicle front-rear direction. , From the tip of this front frame 1 to the engine mount bracket 2
Is a shaft crush zone Z1 that is crushed during a frontal collision, and the engine mount bracket 2 to the toe board 3 is set as a rigid zone Z2 that is difficult to crush, so that the power unit and suspensions can be firmly supported in the rigid zone. The structure is adopted.

In this case, as shown in FIG. 7 (a), the axial crush zone Z1 of the front frame 1 is shown in FIG.
It is simply shown in (a). As shown in the figure, when a collision load is applied to the front frame 1 from the front of the vehicle body, first, the axial crushing resistance force rapidly increases at the initial stage of the collision, and after reaching the peak value P1, the front frame 1 is accordion-shaped. The collision load is absorbed by being crushed by.

At this time, in order to further improve the collision safety performance, the following three means are considered as means for increasing the amount of collision load absorbed by the front frame 1.

1) Axial crush zone Z of the front frame 1
No. 1 is extended forward, and the axial crush stroke is shown in FIG. 8 (b).
Increase by the amount indicated by the hatching.

2) The plate thickness of the front frame 1 is increased to increase the axial crush resistance by the amount shown by the hatching in FIG. 8 (c).

3) The axial crush zone Z1 is increased by moving the engine mount bracket 2 to the rear side, as shown in FIG.
As shown in (b) and FIG. 8 (d), the axial crush stroke is ΔZ
Increase by minutes. In FIG. 8 (d), when the collision load is the same as that in FIG. 8 (a), the peak value P1 of the axial crushing drag force can be relatively reduced as shown by the broken line in the figure.

[0012]

However, 1) In the structure in which the axial crush zone Z1 of the front frame 1 is extended forward, it should be applied to a vehicle such as a light vehicle, etc., in which the front portion of the vehicle body does not have much room. It is difficult.

2) Increasing the plate thickness of the front frame 1 in order to increase the axial crush resistance is not feasible because it increases the weight.

3) When the engine mount bracket 2 is moved rearward to relatively increase the axial crush zone Z1, the supporting position of the power unit is changed, so that the power unit is supported on the front frame 1 in good balance. It becomes difficult to do so, and there arises a problem that the vibration transmission amount of the engine increases.

That is, the inertial spindle in the roll direction of the horizontal power unit extends substantially in the direction of extension of the crankshaft of the engine (vehicle body width direction). The engine vibration is the vibration generated around the crankshaft due to combustion. If the crankshaft and the inertial spindle match, the main vibration associated with the rotational fluctuation is rotation around the inertial spindle. Therefore, by disposing the engine mount bracket 2 on the inertial spindle, it is possible to reduce vibration transmission. Become.

However, although the main shaft of inertia of the horizontal power unit is close to the crank shaft due to the weight distribution, the main shafts do not completely coincide with each other. Therefore, the engine mount bracket 2 is arranged at a position as close as possible to the crankshaft and the inertial main shaft to reduce vibration.

Therefore, when the vibration transmission from the engine is to be minimized, the portion supporting the power unit via the engine mount bracket is uniquely determined and cannot be freely moved.

On the other hand, for example, Japanese Patent Laid-Open No. 2000-10894.
As disclosed in Japanese Unexamined Patent Publication No. 6, a front cross member that connects front end portions of a front frame and a suspension cross member that is arranged in front of a toe board and connects front frames to each other are arranged in a vehicle longitudinal direction. There is disclosed a technique in which the rigidity of the entire front portion of the vehicle body is secured by connecting by a center member extending to the front side, the vibration noise is reduced, and the axial crush resistance during a frontal collision is increased.

However, the vehicle body front structure disclosed in this prior art not only complicates the structure due to the need for the center member, but also has the disadvantage of increasing the weight.

In view of the above circumstances, the present invention has a front body structure of a vehicle capable of enhancing the absorbing performance of the collision load by the front frame with a simple structure without increasing the total length of the vehicle body, the number of parts, and the weight. The purpose is to provide.

[0021]

In order to achieve the above object, a front vehicle body structure of a vehicle according to the present invention has front frames arranged on both sides in a vehicle width direction of an engine room, and both of the front frames include an engine body. The power unit is mounted horizontally via the engine mount bracket, and in the front body structure of the vehicle where the axial crush zone extends from the front end of the front frame to the engine mount bracket, exhaust air is emitted to the rear side of the engine body. A manifold is connected, the engine body is tilted rearward of the vehicle body, and the engine mount bracket is arranged on a line close to the inertial spindle of the power unit.

In such a structure, the engine body is tilted backward as the rear exhaust, so that the center of gravity of the engine body is moved in the direction of the vehicle body, and therefore the engine body is disposed at a position close to the main axis of inertia passing through the center of gravity. The engine mount bracket can be moved to the rear of the vehicle body with respect to the front frame, and the axial crush zone between the position where the engine mount bracket of the front frame is fixed and the front end can be lengthened relatively. it can.

In this case, the absorbability of the collision load of the offset collision can be enhanced by moving the engine mount bracket fixed to the front frame on the driver's seat side to the rear of the vehicle body.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings of FIGS. Here, FIG. 1 is a schematic plan view showing the frame structure of the front part of the vehicle body, and FIG. 2 is a schematic side view of the front part of the vehicle body.

Reference numeral 11 in the figure denotes an engine room provided in the front part of the vehicle body, and front frames 12 are provided on both sides of the engine room 11 in the vehicle width direction. Both front frames 12 extend in the front-rear direction of the vehicle body. Further, the front end portions of both front frames 12 are connected via a cross member 13 such as a front cross member or a bumper beam.

On the other hand, the engine room 11 and the cabin 14
A suspension cross member 16 is disposed in front of the toe board 15 that divides the front frame 12 and the front frame 12 via the suspension cross member 16.

Further, in the engine room 11, a power unit 19 composed of an engine body 17 and a transmission 18 connected in series is mounted horizontally. Both sides of the power unit 19 in the vehicle width direction are elastically supported and fixed to the front frames 12 via engine mount brackets 20. The engine body 17 is a rear exhaust in which an intake manifold (not shown) is joined to a surface that faces the front of the vehicle body, and an exhaust manifold 21 is joined to a surface that faces the rear of the vehicle body.

By the way, when the transmission 18 is common to the engine body 17 by the rear exhaust shown in FIG. 4 and the engine body 17 'by the front exhaust shown in FIG. 5, in order to efficiently perform the layout of the exhaust system. The former is tilted backward and the latter is tilted forward around the crankshaft Lc.

That is, by tilting the rear exhaust engine body 17 rearward, the exhaust system including the exhaust manifold 21 can be guided to the lower part of the floor of the vehicle body without forcibly bending, and the space in the engine room 11 can be effectively used. Can be used. Similarly, the exhaust system can be efficiently guided to the lower side of the vehicle body by inclining the engine main body 17 'by the front exhaust forward.

In this case, both power units 19, 19 '
The inertial principal axes S and S'of FIG. 3 are axes in which the weight around the axes is balanced by the rotational movement, and therefore, compared with the center of gravity G'of the engine body 17 which is tilted forward as shown by the one-dot chain line in FIG. The center of gravity G of the engine body 17, which is tilted backward, is moved to the rear of the vehicle body. Therefore, the engine body 1 is tilted forward
The inertial principal axis S of the engine body 17, which is succeeding to the inertial principal axis S ′ passing through the center of gravity G ′ of 7 ′, is an axis inclined in the clockwise direction in FIG. 3.

Therefore, the engine mount bracket 20 is arranged on the main spindle of inertia S passing through the center of gravity G of the engine body 17 which is tilted backward or at a position close to the main spindle of inertia S.
Also moves to the rear of the vehicle body by ΔZ.

In the present embodiment, the front vehicle body applied to the vehicle used in the right-hand drive zone is shown, and the engine mount fixed to the front frame 12 on the right side of the vehicle, that is, the driver's seat side. The bracket 20 is largely moved to the rear of the vehicle body, and the right front frame 1
By significantly increasing the axial crush zone Z1 of No. 2, it is possible to improve the absorbing performance of the collision load at the time of an offset collision assuming a collision with an oncoming vehicle.

As described above, according to the present embodiment, the engine body 17 with rear exhaust is adopted, and the engine body 17 is tilted backward as shown in FIG. 4, so that the conventional front body shown in FIG. Engine body 17 'tilted forward by exhaust
In contrast, as shown in FIG. 3, the center of gravity G moves rearward from the position of the center of gravity G ′ of the conventional engine body 17 ′, and thus,
The inertia main axis S passing through the center of gravity G is the conventional engine body 1
It can be tilted in the clockwise direction in FIG. 3 in comparison with the inertial principal axis S ′ of 7 ′.

As a result, the axial crush zone Z3 from the position of the front frame 12 on which the engine mount bracket 20 is fixedly mounted on the inertia axle S or in the vicinity of the inertia axle S to the front end is formed by the conventional method. Since it is increased by ΔZ compared to the axial crush zone Z1, the axial crush stroke of the axial crush zone Z3 can be sufficiently secured at the time of frontal collision or offset collision, and the axial crush of the actual crush zone 3 can be ensured. As a result, the collision load F is efficiently absorbed, and the impact is mitigated.

As described above, in the present embodiment, the engine main body 17 is tilted rearward as the rear exhaust gas and the inertia axle shaft S passing through the center of gravity G is moved to the rear of the vehicle body. Since the engine mount bracket 20 arranged in the vicinity of S is moved to the rear of the vehicle body of the front frame 12, the axial crush zone Z1 is substantially extended and the collision load F The amount of absorption can be increased.

By increasing the amount of collision load absorbed by the front frame 12, the toe board 15 is relatively moved.
It is possible to reduce the amount of collision load absorbed by the reaction force supporting member provided on the rear side of the vehicle body, and to reduce the weight of the reaction force supporting member, so that it is possible to reduce the weight of the entire vehicle body.

Further, since the front frame 12 is the same as the conventional one, it is not necessary to increase the plate thickness and the number of parts, the manufacturing and assembling are not complicated, and the rise of the product cost can be suppressed.

The present invention is not limited to the above-described embodiment. For example, in the left steering wheel zone, the shaft crush zone Z3 of the front frame 12 on the left side of the vehicle body, that is, the driver's seat side is set to the right side front frame 12. Axial crush zone Z
By ensuring the length longer than 3, it is possible to enhance the collision load absorption performance against the offset collision applied in the left-hand drive range.

[0039]

As described above, according to the present invention,
It is possible to improve the collision load absorption performance of the front frame with a simple structure without increasing the overall length of the vehicle body, the number of parts, and the weight.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a frame structure of a front part of a vehicle body.

FIG. 2 is a schematic side view of a front portion of a vehicle body.

FIG. 3 is a schematic plan view of an essential part showing a frame structure of a front part of a vehicle body.

FIG. 4 is a schematic diagram of a power unit including an engine body with rear exhaust.

FIG. 5 is a schematic view of a power unit including an engine body with front exhaust.

FIG. 6 is a schematic plan view of an essential part showing a conventional frame structure of a front part of a vehicle body.

FIG. 7 is an explanatory view showing a conventional shaft crushing state.

FIG. 8 is an explanatory view showing absorption characteristics of a collision load for each state.

[Explanation of symbols]

11 engine room 12 front frame 17 engine body 19 power units 20 engine mount bracket 21 Exhaust manifold S inertial spindle Z3 axis crush zone

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenzo Komatsu             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd. (72) Inventor Eri Eri             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd. (72) Inventor Kunio Kameyama             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd. F-term (reference) 3D035 CA01 CA13 CA28

Claims (2)

[Claims] 1. A front frame is disposed on both sides of an engine room in a vehicle width direction, and a power unit including an engine body is horizontally mounted on both of the front frames via an engine mount bracket. In a front body structure of a vehicle having an axial crush zone from a front end to the engine mount bracket, an exhaust manifold is connected to a rear side surface of the engine body, and the engine body is inclined rearward of the vehicle body. A front body structure of a vehicle, wherein an engine mount bracket is arranged on a line in proximity to the inertial spindle of the power unit. 2. The front support structure for a vehicle according to claim 1, wherein the engine mount bracket fixed to the front frame on the driver's seat side is moved rearward of the vehicle body.