JP2000255448A - Rear subframe structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save space for disposing a rear subframe, and to simultaneously improve the supporting rigidity of a differential gear. SOLUTION: A rear subframe 4 is composed of a front side horizontal member, longitudinal members 43 and 43 and a rear side horizontal member 42. The front side horizontal members is formed to be bent forward from the center part of its car width direction toward both ends to narrow a gap between the front and rear side horizontal members, and to widen a gap between the connecting position of the front side horizontal member with a rear side frame 5 and the rear side frame connecting position with the longitudinal member. The front side horizontal member is formed to be bent upward from both ends to the center part such that its center part is located higher than the disposing position of the rear side horizontal member. The pair of longitudinal members are formed to be bent upward. The front part of a differential gear 32 is supported by the front side horizontal member, and its rear part is supported by the rear side horizontal member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear subframe structure of a vehicle used to support a differential device.

[0002]

2. Description of the Related Art Conventionally, as a rear subframe of this kind of vehicle, one supporting a differential device has been known (for example, see Japanese Patent Application Laid-Open No. 7-266905). In this vehicle, a pair of lateral members extending in the vehicle width direction are arranged apart from each other in the vehicle front-rear direction so as to connect the rear subframes to each other, and both ends of the pair of lateral members are connected to each other. A pair of vertical members extending in the vehicle front-rear direction form a substantially girder shape in plan view. Then, the differential device is supported in a state where the differential device is located inside the girder of the rear subframe.

[0003]

However, there is a demand for lowering the vehicle floor. In this case, by reducing the thickness of the fuel tank in the vertical direction, the floor of the vehicle floor can be reduced.However, in order to secure the capacity of the fuel tank, the fuel tank is moved in the longitudinal direction of the vehicle. It is necessary to expand the tank capacity. When the fuel tank is expanded in the front-rear direction in this manner, the space for disposing the rear sub-frame disposed on the rear side of the fuel tank is reduced in the front-rear direction.

However, since the rear sub-frame supports the differential device, the rear sub-frame has a rotational reaction force of a propeller shaft extending in the vehicle front-rear direction and a vehicle width perpendicular to the propeller shaft. Due to the rotational reaction force of the drive shaft extending in the direction, a moment about the axis X that tilts by a predetermined angle with respect to the vehicle longitudinal direction acts (see a two-dot chain line in FIG. 1). To counter this moment, it is necessary to improve the rigidity of the rear subframe against torsion,
In order to improve the rigidity against this torsion, the space between the front side member and the rear side member is widened so that the mounting position between the rear subframe and the rear side frame is widened in the front-back direction. It is effective.
However, if the space between the front side member and the rear side member is widened in this way, it is not possible to meet the demand for reducing the space for disposing the rear subframe.

As described above, it is extremely difficult to achieve both a reduction in the space for disposing the rear subframe and an increase in the support rigidity of the differential device.

[0006] The present invention has been made in view of such circumstances, and an object of the present invention is to achieve both a reduction in the space for disposing the rear subframe and an improvement in the support rigidity of the differential device. It is to plan.

[0007]

In order to achieve the above object, the present inventor has proposed that a lateral member constituting a rear sub-frame be moved forward from the center in the vehicle width direction to both ends in the vehicle front-rear direction. The present invention has been completed in view of the fact that the arrangement space of the rear sub-frame in the vehicle front-rear direction is reduced, while the rigidity against torsion can be improved.

More specifically, the present invention relates to a front lateral member which extends in the vehicle width direction so as to connect a pair of rear side frames disposed on both sides in the vehicle width direction, A pair of longitudinal members extending outward in the vehicle width direction toward the rear in the vehicle front-rear direction and arranged to connect the front side member and the side frame to each other; and a vehicle front-rear direction of the front side member. And a rear lateral frame extending in the vehicle width direction so as to connect the pair of vertical members to each other at a rear position of the rear member, and a rear sub-frame for supporting the differential device. In this vehicle, the front side member is formed so as to bend forward in the vehicle front-rear direction from the center in the vehicle width direction toward both ends, and the rear sub-frame is connected to the front side member and the rear side member. It is a specific feature that the space between the front frame member and the side frame connection position of the front lateral member and the side frame connection position of the vertical member are widened while the space between the front member and the member is reduced. Here, the "front side member" is formed so as to be bent upward from both ends to the center so that the center portion in the vehicle width direction is located above the position where the rear side member is disposed. Is also good. Further, the “pair of vertical members” may be formed so as to be curved upward. And the rear subframe is
The front portion of the differential device may be supported by the front lateral member, while the rear portion may be supported by the rear lateral member.

In this case, the space between the front lateral member and the rear lateral member is reduced, so that the space in which the rear subframe is disposed in the front-rear direction can be reduced. on the other hand,
By increasing the distance between the side frame connection position of the front lateral member and the side frame connection position of the vertical member, the rigidity of the rear subframe against twisting is improved. Thereby, it is possible to improve the support rigidity of the differential device and also to improve the durability against the repetitive action of the torsion, thereby saving the space for disposing the rear subframe and improving the support rigidity of the differential device. It is compatible with improvement.

By displacing the position of the central portion of the front side member and the position of the rear side member up and down, the rear subframe support position at the front of the differential device and the rear subframe support position at the rear are provided. The position and height change. For this reason, the rear sub-frame can more effectively counter the twist input from the differential device. Furthermore, by forming this vertical member to be curved upward,
The rear subframe can more effectively counter the twist.

[0011] Such a rear subframe may be configured to support a rear suspension arm.

Further, the fuel tank may be provided at a position forward of the rear subframe in the vehicle front-rear direction, and the rear surface of the fuel tank may be formed in a shape along the front side member in plan view. In this case, since the space for arranging the rear subframe is reduced,
The fuel tank can be expanded in the vehicle front-rear direction. For this reason, even if the thickness of the fuel tank in the vertical direction is reduced, its capacity is sufficiently ensured. As a result, the vehicle floor is reduced. Further, by forming the rear surface of the fuel tank along the front side member in plan view, for example, even if the fuel tank retreats at the time of a collision or the like, the fuel tank is entirely formed by the front side member. To receive it. Therefore, the fuel tank is prevented from being damaged, and interference between the fuel tank and the differential device is prevented.

[0013] In addition, the rear subframe may be formed of a pipe member. In this case, the rigidity of the rear subframe itself is improved, and the supporting rigidity of the differential device is further improved.

[0014]

As described above, according to the vehicle rear subframe structure of the present invention, it is possible to achieve both a reduction in the space required for disposing the rear subframe and an improvement in the support rigidity of the differential device. .

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a structure of a rear portion of a vehicle according to an embodiment of the present invention, wherein 1 is a fuel tank disposed below a floor panel 8 and 2 is omitted from the drawings disposed in front of the vehicle. The propeller shafts 31 and 32 are arranged to extend rearward from the engine transmission unit of the vehicle, 31 and 32 are 4WD units connected to the rear end of the propeller shaft 2, and the differential gear 4 as a rear differential device is This is a rear sub-frame that supports the differential gear 32. In addition, FIG.
In FIG. 3, only the right rear wheel 7 is illustrated, and illustration of the left rear wheel is omitted.

The rear sub-frame 4 includes a front lateral member 41 extending in the vehicle width direction so as to connect rear side frames 5 and 5 disposed in the vehicle front-rear direction. A pair of vertical members 4 extending from a substantially central position in the vehicle width direction of the lateral member 41 to the rear side in the vehicle front-rear direction and connected to the rear side frames 5 and 5 respectively
3, 43, and a rear side member 42 extending in the vehicle width direction so as to connect the pair of vertical members 43, 43 to each other. (See FIG. 1 or FIG. 4). The front lateral member 41 is formed so as to bend forward from its center to both ends. For this reason,
While the distance between the front lateral member 41 and the rear lateral member 42 is reduced, the distance between the coupling position of the front lateral member 41 to the rear subframe 5 and the coupling position of the vertical member 43 to the rear side frame 5 is reduced. It is wider (see FIG. 1). The front lateral member 41 is formed to bend upward from both ends in the vehicle width direction to the center. Thereby, this front side lateral member 41
Is located above the rear lateral member 42 (see FIG. 2).

Each of the vertical members 43 is formed so as to be curved upward between the front horizontal member 41 and the rear horizontal member 42 so as to connect the both 41 and 42 to each other. Thereby, interference between the vertical member 43 and the drive shaft is avoided. Each of the vertical members 43 is formed so as to extend obliquely upward between the rear member 42 and the rear side frame 5, so that the vertical member 43 is larger than the rear horizontal member 42. It is connected to the rear side frame 5 located above (see FIG. 2 or FIG. 3). The connection between the vertical member 43 and the rear side frame 5 is as follows. That is, a rubber mount 43a is provided at an end of the vertical member 43, and a tube 92 welded and fixed to the rear side frame 5 penetrates the rubber mount 43a. A bolt 91 is passed through the pipe 92 so that its head comes into contact with the upper surface of the rear side frame 5, while a nut 93 is screwed in from the lower end of the bolt 91 to attach the rubber mount 43 to the rear side frame 5. 5
(See FIG. 5). The front side member 41
Rubber mounts 41a, 41a disposed at both ends of
It is configured similarly.

The above-mentioned front and rear lateral members 4
The first and second members 42 and the pair of vertical members 43 may be formed of pipe members.

As shown in FIG. 1, FIG. 2, or FIG. 4, the differential gear 32 has a rear portion mounted and supported on the lower surface of the rear side member 42 via a transmission mount 32a. On the other hand, the above 4W
A connection portion between the D unit 31 and the differential gear 32, that is, a front portion of the differential gear 32 is mounted and supported on a lower surface of the front side member 41 via transmission mounts 31a, 31a. Thus, the front side and the rear side of the differential gear 32 are supported by the rear sub-frame 4 at different positions in the height direction (see FIG. 2).

The fuel tank 1 is shown in FIG.
Alternatively, as shown in FIG. 3, a right tank portion 11 and a left tank portion 12 disposed on both left and right sides in the vehicle width direction with the propeller shaft interposed therebetween, and the right and left tank portions in a front portion of the fuel tank 1. There is provided a communication portion 13 that communicates the fuel tanks 11 and 12 with each other, and a reinforcing portion 14 on the rear side of the communication portion 13 for improving the rigidity of the fuel tank. The communication portion 13 is located at an upper position of the propeller shaft 2, while the reinforcing portion 14 is located at an upper position of the 4WD unit 31. Further, both the communication portion 13 and the communication portion 14 are formed so that the thickness in the vertical direction is relatively small, and thereby the thickness in the vertical direction of the fuel tank 1 is reduced. For this reason, the vehicle floor can be made low (see FIG. 3). The rear surface of the fuel tank 1 is formed in a shape along the front side member 41 in plan view (see FIG. 1). The fuel tank 1 is fixed to the vehicle by being sandwiched between a floor panel 8 and tank belts 15, 15 arranged so as to connect the lateral members 6 and the rear side frames.

The rear suspension of the right rear wheel 7 is shown in FIG.
As shown in FIG. 4, the arm has first to third arms 61 to 63, and a wheel-side support member is provided at the wheel-side end of each of the arms 61 to 63 so that the wheel carrier 64 can swing. It is to be connected. On the other hand, vehicle-side support members 61a are provided at the vehicle-side ends of the first to third arms 61 to 63, respectively.
To 63a. Then, the first arm 61
The second arm 62 is mounted above the vertical member 43, and the third arm 63 is mounted below the front horizontal member 41. On the other hand, the wheel carrier 64 extends forward and is attached to the side frame 5 (see FIG. 1).

Next, the operation and effect of the above embodiment will be described.

Since the space between the front side lateral member 41 and the rear side lateral member 42 is narrow, the space for arranging the rear sub-frame 4 in the vehicle front-rear direction can be reduced. On the other hand, the connecting positions of the front side members 41 to the side frames 5 and 5 and the vertical members 43 and 4
Since the connection positions of the side frames 5 and 5 are separated from each other, the rigidity of the rear subframe 4 against torsion when a moment about the axis X due to the rotational reaction force of the propeller shaft 2 and the drive shaft is input is improved. (See FIG. 1).

Also, since the vertical members 43 are directly connected to the rear side frames 5, 5,
When the moment is input, this force can be directly transmitted to the rear side frame 5. For this reason, the rear subframe can effectively counter the twist. In this manner, the support rigidity of the differential gear 32 can be improved, and the durability against the repeated action of the torsion can be improved, so that the space for disposing the rear subframe 4 can be reduced. The improvement of the support rigidity of the differential gear 32 can be achieved at the same time.

The height at which the differential gear 32 is supported is changed by vertically displacing the positions of the central portion of the front side member 41 and the rear side member 42 (see FIG. 2 or 3). In other words, the rear subframe 4 can more effectively resist torsion. Further, by forming the vertical member 43 to be curved upward, the rear sub-frame 4 can more effectively resist torsion.

In addition, the front and rear side members 41,
Since the pipe 42 and the vertical members 43 are each formed by a pipe member, the rigidity of the rear subframe 4 itself is improved, and the rigidity of the support of the differential gear 32 can be further improved.

Furthermore, since the space for disposing the rear sub-frame 4 is reduced, the fuel tank 1 can be expanded in the front-rear direction.
Thereby, even if the thickness of the fuel tank 1 in the vertical direction is reduced, the capacity of the fuel tank 1 can be sufficiently ensured. As a result, the vehicle floor can be lowered.

Further, by forming the rear surface of the fuel tank 1 along the front lateral member 41 in a plan view (see FIG. 1), for example, even if the fuel tank 1 retreats at the time of collision or the like, The above-mentioned front side member 41
Can receive the fuel tank 1 as a whole. For this reason, the fuel tank 1 can be prevented from being damaged, and interference between the fuel tank 1 and the 4WD unit 31 and the differential gear 32 can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view showing a rear structure of a vehicle.

FIG. 2 is an explanatory front view showing a rear structure of the vehicle.

FIG. 3 is an explanatory side view showing a rear structure of the vehicle.

FIG. 4 is an explanatory perspective view showing a rear sub-frame.

FIG. 5 is an end view showing an AA end face of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fuel tank 4 Rear subframe 5, 5 Rear side frame 32 Differential gear (differential device) 41 Front side member 42 Rear side member 43, 43 Vertical member 61-63 First-third suspension arm (rear suspension arm)

Claims (7)

[Claims] 1. A front lateral member extending in the vehicle width direction so as to connect a pair of rear side frames disposed on both sides in the vehicle width direction to each other, and a rear side in the vehicle front-rear direction from the front lateral member. A pair of vertical members extending outward in the vehicle width direction and arranged to connect the front side member and the side frame to each other; and a rear position of the front side member in the vehicle front-rear direction. A rear lateral frame that extends in the vehicle width direction so as to connect the pair of vertical members to each other, and includes a rear subframe that supports a differential device; The rear sub-frame is formed so as to bend forward from the center toward both ends in the vehicle front-rear direction. Rear subframe structure of a vehicle, characterized in that the distance between the side frame connecting position and the side frame connecting positions of the longitudinal members of the bar is formed to be wider. 2. The vehicle according to claim 1, wherein the front lateral member is moved upward from both ends toward the central portion such that a central portion in the vehicle width direction is located above a position where the rear lateral member is disposed. A rear subframe structure for a vehicle, which is formed to be bent. 3. The rear subframe structure for a vehicle according to claim 1, wherein the pair of vertical members are formed to be curved upward. 4. The vehicle according to claim 1, wherein a front portion of the differential device is supported by a front lateral member, and a rear portion of the differential device is supported by a rear lateral member. Rear subframe structure. 5. The rear subframe structure for a vehicle according to claim 1, wherein the rear subframe is configured to support a rear suspension arm. 6. The fuel tank according to claim 1, wherein a fuel tank is disposed at a position forward of the rear sub-frame in a vehicle front-rear direction, and a rear surface of the fuel tank has a front lateral member in plan view. A rear sub-frame structure for a vehicle, wherein the rear sub-frame structure is formed in a shape that conforms to the shape of the vehicle. 7. The vehicle rear subframe structure according to claim 1, wherein the rear subframe is formed of a pipe member.