JPH0558440U - Lower car body structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To make it possible to suppress the bending angle of a propeller shaft by a very simple and low-cost means. A rear differential device 3 for transmitting power from a power unit 1 via a propeller shaft 2 is provided on a rear wheel axle 5, and an axle casing 6 provided on both sides of the rear differential device 3 is supported by a leaf spring 7. In the lower body structure of an automobile as described above, the rear differential device 3 is swingable with respect to the rear wheel axle 5 in a front lower direction or a front higher direction.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a lower body structure of an automobile, and more specifically, a rear differential device for transmitting power from a power unit via a propeller shaft is provided on a rear wheel axle, and axles provided on both sides of the rear differential device. It relates to the lower body structure of an automobile in which the casing is supported by leaf springs.

[0002]

[Prior Art]

 In a vehicle such as a one-box car in which the power unit, which is the power source, is located under the front seat occupant and the front and rear distances to the rear wheels, which are the driving wheels, are short, the power from the power unit is applied to the rear wheel side (specifically, Inevitably, the length of the propeller shaft transmitted to the rear differential device) is inevitably shortened.

In the case of such a vehicle, as disclosed in Japanese Utility Model Laid-Open No. 147807/58, leaf springs that form part of the suspension device are provided with axle casings attached to both sides of the rear differential device. Although it is customary to support the propeller shaft in such a way, the bending angle of the propeller shaft (that is, the bending angle of the propeller shaft relative to the axis of the power unit) caused by the vertical movement of the rear wheel is reduced by adopting such a support structure. This may make it difficult to transmit power from the power unit smoothly.

In particular, in the case of a four-wheel drive vehicle, since a transfer device is required, the front-rear dimension of the power unit is unavoidably long, and the length of the propeller shaft is further shortened. Therefore, in order to reduce the bending angle of the propeller shaft, the rear suspension device is set to the independent suspension system to fix the rear differential device to the vehicle body side, and the link type support structure is used to improve the vertical movement trajectory of the rear differential device. Sometimes had to be adopted. In this case, the structure may be complicated and the cost may be increased.

[0005]

[Problems to be solved by the device]

 As described above, if the power transmission from the power unit cannot be smoothly performed, noise is increased, so that smooth power transmission is required.

The present invention has been made to solve the above problems, and an object thereof is to make it possible to suppress the bending angle of a propeller shaft by a very simple and low-cost means. is there.

[0007]

[Means for Solving the Problems]

 In the invention of claim 1, as a means for solving the above-mentioned problems, a rear differential device for transmitting power from a power unit via a propeller shaft is provided on a rear wheel axle, and is provided on both sides of the rear differential device. In the lower vehicle body structure of an automobile in which the axle casing is supported by leaf springs, the rear differential device can be swung forward or downward with respect to the rear wheel axle.

According to the second aspect of the invention, as a means for solving the above-mentioned problems, a rear differential device for transmitting power from a power unit via a propeller shaft is provided on a rear wheel axle, and both sides of the rear differential device are provided. In the lower body structure of an automobile in which the axle casing provided in the axle is supported by leaf springs, parallel rotary shafts integrally provided in the axle casing are rotatably supported by the leaf springs. ..

According to a third aspect of the present invention, as means for solving the above-mentioned problems, in the lower body structure of the automobile according to the second aspect, the spring coefficient of the leaf spring is set to the front side of the rotary shaft support portion. It is set to be smaller on the rear side compared to.

According to a fourth aspect of the present invention, as means for solving the above-mentioned problems, in the lower vehicle body structure of the automobile according to the second aspect, the vehicle is positioned above the axle casing and on the front side of the axle casing. A link member for controlling the posture of the rear differential device is interposed between the vehicle body member and the rear differential device.

[0011]

[Action]

 According to the first aspect of the invention, the following effects can be obtained by the above means.

That is, as the rear wheel moves up and down, the rear differential device can take a front-down or front-up posture, and the bending angle of the propeller shaft can be suppressed to a small value.

According to the second aspect of the invention, the following effects can be obtained by the above means.

That is, as the rear wheel moves up and down, the axle casing oscillates forward or backward, and as a result, the rear differential device can take a forward-downward or forward-upward posture, and the bending angle of the propeller shaft is small. It will be suppressed.

According to the third aspect of the invention, the following effects can be obtained by the above means.

That is, the axle casing swings forward or backward in accordance with the behavior of the leaf spring due to the vertical movement of the rear wheels, and as a result, the rear differential device can take a front-down or front-up posture. , The bending angle of the propeller shaft can be kept small.

In the device of the fourth aspect, the following actions are obtained by the above means.

That is, when the axle casing swings forward or backward with the vertical movement of the rear wheels, the posture control function of the link member allows the rear differential device to take a forward-downward or forward-upward posture, and the propeller. The bending angle of the shaft can be kept small.

[0019]

[Effect of the device]

 According to the invention of claim 1, the rear differential device for transmitting the power from the power unit via the propeller shaft is provided on the rear wheel axle, and the axle casings provided on both sides of the rear differential device are leaf springs. In the lower body structure of an automobile supported by a vehicle, the rear differential device can be swung forward or backward with respect to the rear wheel axle, and the rear differential can be moved along with the rear wheel vertical movement. Since the device can take the posture of lowering or raising to the front, the bending angle of the propeller shaft can be kept small and the driving force transmission path becomes a straight line, so noise generation can be greatly reduced. Has a positive effect. In addition, since the bending angle of the propeller shaft is kept small, it is possible to shorten the wheelbase, which has the effect of increasing the degree of freedom in layout.

According to the second aspect of the present invention, the rear differential device for transmitting the power from the power unit through the propeller shaft is provided on the rear wheel axle, and the axle casings are provided on both sides of the rear differential device. In the lower body structure of an automobile, in which the leaf springs are supported, the parallel rotation shafts integrally provided in the axle casing are rotatably supported by the leaf springs so that the rear wheels move up and down. As a result, the axle casing oscillates forward or backward, and as a result, the rear differential device is allowed to take the front lowering or the front uppering posture, so that the bending angle of the propeller shaft is kept small and the driving force Since the transmission path is linear, it is possible to significantly reduce noise generation. There is a practical effect. In addition, since the bending angle of the propeller shaft is kept small, it is possible to shorten the wheelbase, which has the effect of increasing the degree of freedom in layout.

According to the invention of claim 3, in the lower body structure for an automobile according to claim 2, the spring coefficient of the leaf spring is set so that the rear side is smaller than the front side of the rotary shaft support portion. Then, the axle casing can be reliably swung forward or backward in response to the vertical movement of the rear wheels, and as a result, the rear differential device can take a forward-downward or forward-forwarding posture. Since the bending angle of the propeller shaft is suppressed to a small value and the driving force transmission path is linear, there is a practical effect that noise generation can be greatly reduced. Also, since the bending angle of the propeller shaft can be kept small, it is possible to shorten the wheelbase, which has the effect of increasing the layout flexibility.

According to the invention of claim 4, in the lower body structure of the automobile according to claim 2, the rear differential device is provided between the upper part of the axle casing and the body member located on the front side of the axle casing. A link member for controlling the posture is provided to ensure that the axle casing swings forward or backward in response to the vertical movement of the rear wheels, and as a result, the rear differential device moves forward or downward. Since the posture can be taken, the bending angle of the propeller shaft is kept small and the driving force transmission path becomes linear, so there is a practical effect that noise generation can be greatly reduced. In addition, since the bend angle of the propeller shaft can be kept small, the wheelbase can be shortened, which has the effect of increasing the layout flexibility.

[0023]

【Example】

 Hereinafter, some preferred embodiments of the present invention will be described with reference to the accompanying drawings.

First Embodiment FIGS. 1 to 3 show a lower body structure of an automobile according to a first embodiment of the present invention. The present embodiment corresponds to the inventions of claims 1 to 3.

In the lower vehicle body structure of the vehicle of the present embodiment, the rear differential device 3 for transmitting the power from the power unit 1 arranged at the front portion of the vehicle body via the propeller shaft 2 has an axle for the rear wheel 4. 5, axle casings 6 provided on both sides of the rear differential device 3 are supported by leaf springs 7.

The power unit 1 is composed of an engine, a mission and the like.

Universal joints 8 and 9 are provided between the propeller shaft 2, the power unit 1 and the rear differential device 3.

The front end and the rear end of the leaf spring 7 are supported on the lower surface of the main frame 10 which is lateral to the vehicle body and extends in the front-rear direction via front and rear mounting brackets 11 and 12. .. A shackle arm 13 that can swing in the front-rear direction is provided between the rear mounting bracket 12 and the rear end of the leaf spring 7.

A rotary shaft 14 parallel to the axle casing 6 is integrally fixed to the lower surface of the axle casing 6 via a pair of mounting pieces 15 and 15, and the rotary shaft 14 is provided with the leaf. The spring 7 is rotatably supported by an intermediate portion of the spring 7 via a fixture 16. In the case of this embodiment, the rotary shaft 14 is rotated forward or backward in response to the vertical movement of the rear wheel 4, and the axle casing 6 is swung forward or backward in accordance with the rotation. As a result, the rear differential device 3 is swung so as to be in a front-down or front-up posture. In other words, in the present embodiment, the rear differential device 3 is swingably supported with respect to the rear wheel axle 5 so as to be in a front lowering or front rising posture.

Further, in the present embodiment, the leaf spring 7 is arranged such that the number of front side (ie, three) of the support portion of the rotary shaft 14 is larger than the number of rear side (ie, two). It is configured. That is, the spring coefficient of the leaf spring 7 is set to be smaller on the rear side than on the front side of the support portion of the rotating shaft 14. With this configuration, the amount of elastic deformation of the leaf spring 7 when the rear wheel 4 moves up and down becomes larger on the rear side than on the front side of the support portion of the rotating shaft 14, and the rear wheel When the vehicle is moving up, the vehicle is in the front-down state, while when the rear wheel 4 is moving downward, it is in the front-up state. Therefore, the axle casing 6 can be reliably swung forward or backward, and as a result, the rear differential device 3 can take a front lowering or a front rising posture.

In the drawings, reference numeral 17 is a side sill, 18 is a cross member provided between the main frames 10 and 10 on both sides, and 19 is a torque box provided between the main frame 10 and the side sill 17. Is.

The bending angle of the propeller shaft 2 and the behavior of the rear differential device 3 at this time will be described in detail with reference to FIGS. 4 and 5. 4 shows the case of the present invention, and FIG. 5 shows the case of the conventional example (that is, the axle casing 6 is fixedly supported by the leaf spring 7).

In the case of the conventional example, as shown in FIG. 5, when the maximum allowable bending angle of the propeller shaft 2 is α °, the vertical motion locus of the axle casing 6 becomes equal to the parallel link, and its stroke width is S. Become.

However, in the case of the present invention, since the swinging of the axle casing 6 to the front side or the rear side (that is, the front lowering posture or the front raising posture of the rear differential device 3) is allowed, As shown in FIG. 4, the bending angle α is allowed at the front and rear ends of the propeller shaft 2. Therefore, the allowable vertical movement stroke of the axle casing 6 is about twice that of the conventional example (that is, about 2S). As can be seen from this, if the vertical stroke of the rear wheel 4 (in other words, the axle casing 6) is set to be the same as that of the conventional example, the bending angle of the propeller shaft 2 can be suppressed to be small. ..

As described above, when the bending angle of the propeller shaft 2 is suppressed to a small value, the driving force transmission path becomes linear, and noise generation can be significantly reduced. In addition, since the bending angle of the propeller shaft 2 is kept small, it is possible to shorten the wheelbase and increase the degree of freedom in layout.

Second Embodiment FIGS. 6 to 8 show a lower body structure of an automobile according to a second embodiment of the present invention. This embodiment corresponds to the inventions of claims 1, 2 and 4.

In the case of the present embodiment, the leaf springs 7 have the same spring coefficient in the front-rear direction, but between the upper part of the axle casing 6 and the torque box 19 located in front of the axle casing 6, the rear A link member 20 for controlling the attitude of the differential device 3 is provided. Both ends of the link member 20 are rotatably supported by the axle casing 6 and the torque box 19 via brackets 21 and 22. The other configurations are similar to those of the first embodiment, and thus the description thereof is omitted.

By virtue of the above configuration, in the present embodiment, as shown in FIG. 9, the vertical movement locus of the axle casing 6 when the axle casing 6 moves up and down in response to the vertical movement of the rear wheel 4. Comparing P with the upward and downward movement locus P ′ of the leaf spring 7 (in other words, the rotating shaft 14), the locus P of the axle casing 6 is the same as that of the link member 20 when the axle casing 6 is moving upward. Due to the regulation force, the locus P ′ of the leaf spring 7 is displaced to the front side of the vehicle body, and when the axle casing 6 moves downward, the locus P of the axle casing 6 receives the regulation force of the link member 20. It is displaced to the rear side of the vehicle body from the locus P'of the leaf spring 7. As a result, the axle casing 6 can be reliably swung forward or backward, and as a result, the rear differential device 3 can take a front-down or front-up posture. Therefore, as in the case of the first embodiment, the bending angle of the propeller shaft 2 is suppressed to a small value, the driving force transmission path becomes linear, and the noise generation is significantly reduced, and the wheel base can be shortened. It will be possible and the freedom of layout will be increased.

The invention of the present application is not limited to the configuration of each of the above-described embodiments, and it goes without saying that the design can be changed as appropriate within the scope of the invention.

[Brief description of drawings]

FIG. 1 is a side view of essential parts showing a lower body structure of an automobile according to a first embodiment of the present invention.

FIG. 2 is a plan view of essential parts showing a lower body structure of an automobile according to Embodiment 1 of the present invention.

FIG. 3 is a perspective view of a main part of a lower body structure of an automobile according to the first embodiment of the present invention.

FIG. 4 is a schematic view illustrating behaviors of a propeller shaft and an axle casing in a lower body structure of an automobile according to a first embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating behaviors of a propeller shaft and an axle casing in a lower body structure of an automobile according to a conventional example.

FIG. 6 is a side view of essential parts showing a lower body structure of an automobile according to a second embodiment of the present invention.

FIG. 7 is a plan view of relevant parts showing a lower body structure of an automobile according to a second embodiment of the present invention.

FIG. 8 is a perspective view of an essential part showing a lower body structure of an automobile according to a second embodiment of the present invention.

FIG. 9 is a schematic view for explaining the behavior of the axle casing in the lower vehicle body structure for an automobile according to the second embodiment of the present invention.

[Explanation of symbols]

1 is a power unit, 2 is a propeller shaft, 3 is a rear differential device, 4 is a rear wheel, 5 is an axle, 6 is an axle casing, 7 is a leaf spring, 14 is a rotary shaft, 19 is a body member (torque box), and 20 is Link member.

Claims (4)

[Scope of utility model registration request] 1. A lower part of an automobile in which a rear differential device for transmitting power from a power unit via a propeller shaft is provided on a rear wheel axle, and axle casings provided on both sides of the rear differential device are supported by leaf springs. A vehicle body structure, wherein the rear differential device is capable of swinging forward or downward with respect to the rear wheel axle. 2. A lower part of an automobile in which a rear differential device for transmitting power from a power unit via a propeller shaft is provided on a rear wheel axle, and axle casings provided on both sides of the rear differential device are supported by leaf springs. A lower vehicle body structure for an automobile, wherein a parallel rotating shaft integrally provided in the axle casing is rotatably supported by the leaf spring. 3. The lower vehicle body of the automobile according to claim 2, wherein a spring coefficient of the leaf spring is set so that a rear side of the rotary shaft support portion is smaller than a front side thereof. Construction. 4. A link member for controlling the posture of the rear differential device is interposed between an upper portion of the axle casing and a vehicle body member located on the front side of the axle casing. The lower body structure for an automobile according to claim 2.