JPS6126116Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a support device for supporting a differential gear case on a vehicle body in an automobile or the like equipped with an independent suspension system.

Generally, in automobiles equipped with this type of independent suspension system, such as a semi-trailing arm system, the differential gear case is mounted on the vehicle body in order to reduce unsprung weight and improve riding comfort. Support is being provided.

Conventionally, as a support device for supporting such a differential gear case on a vehicle body, the front end of the differential gear case is fixed to the middle part of a front support member extending in the left-right direction, and both left and right ends of the front support member are fixed. are supported on the vehicle body via first and second mount rubber bodies, respectively, and approximately the center of the rear end of the differential gear case is supported on the vehicle body via a third mount rubber body, and two points on the front side are supported on the vehicle body through first and second mount rubber bodies. and posterior 1
It is well known that the differential gear case is supported on the vehicle body by a total of three points.

However, in the above-mentioned conventional device, when forward driving force is transmitted to the propeller shaft and the left and right drive shafts arranged orthogonally to the propeller shaft when the vehicle accelerates forward, the power is transmitted by the left and right drive shafts. In the end,
A moment of the same magnitude in the forward rotational direction and the opposite direction of each drive shaft is generated on both the left and right sides of the differential gear case.
The same compressive stress acts on the mount rubber body, but depending on the propeller shaft, a moment is generated in the differential gear case in the same direction as the forward rotation direction of the propeller shaft, and one, for example, the first mount rubber body, A tensile stress acts on the second mount rubber body, while a compressive stress acts on the second mount rubber body, which faces the first mount rubber body, so that different stresses are applied to the first and second mount rubber bodies. This causes a difference in the amount of deformation of the first and second mount rubber bodies, resulting in a problem in that the vehicle body tilts in the left-right direction, which adversely affects the driving performance and steering performance of the vehicle.

Therefore, in order to deal with this problem, the support position of the rear end of the differential gear case relative to the vehicle body is made eccentric in either the left or right direction from the axis of the propeller shaft using a separately provided support lever member. A method has been proposed in which the moment due to the forward driving force of the propeller shaft is eliminated (Japanese Patent Laid-Open No. 47-207), but this proposal requires a separate support lever member. Not only does this increase cost and disadvantage in terms of space, but the support point of the support lever member (third mount rubber body) is offset from the center of the rear end of the differential gear case to the left and right from the axis of the propeller shaft. Since it is offset, when a vertical force is applied to the differential gear case, a moment is generated around the support point (third mount rubber body), which makes it impossible to absorb vibration smoothly. There is. It is also conceivable to support the rear end of the differential gear case to the vehicle body at two points on the left and right sides, but in that case, the number of required mount rubber bodies will increase and the number of assembly steps will be reduced. This has the disadvantage of increasing costs.

The present invention has been made in view of these points, and includes a third mount rubber body interposed between approximately the center of the rear end of the differential gear case and the vehicle body, whose center axis coincides with the axis of the propeller shaft. It is composed of cylindrical rubber bodies arranged in the same direction, and an initial torsional stress is applied to the rubber bodies in advance around a predetermined central axis in a direction that offsets the moment generated by the forward driving force of the propeller shaft. By keeping the
When the automobile accelerates forward, the moment caused by the propeller shaft is offset by the initial torsional stress of the third mount rubber body, and the differential gear case can be moved in the vertical direction with a simple structure without increasing the number of parts. The purpose of the present invention is to provide a support device for a differential gear case that can smoothly absorb vibrations without generating unnecessary moments around the third mount rubber body, thereby improving running performance and steering performance. be.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Figures 1 and 2 show an example in which the suspension device is applied to a car equipped with a semi-trailing arm type independent suspension system on the rear wheels. The propeller shaft 2 is arranged in the longitudinal direction, and the front end of the propeller shaft 2 is connected to a transmission (not shown), and the rear end is built into a differential gear case 4 via a hook joint 3. It is connected to a differential gear (not shown). Drive shafts 5, 5 are disposed on the left and right sides of the differential gear case 4, respectively, in a direction perpendicular to the propeller shaft 2 and in a straight line with each other. The central end) is connected to the differential gear via a constant velocity joint 6, and the other end is connected to rear tires 8, 8 via wheel bearings 7, which control the rotation of the propeller shaft 2. It is provided so that the signal is transmitted to both rear tires 8, 8 via the differential gear and drive shafts 5, 5, and causes both rear tires 8, 8 to rotate.

An intermediate portion of a front support member 9 extending in the left-right direction is fixed to the upper surface of the front end portion of the differential gear case 4, and the left and right end portions of the front support member 9 have first and second mount rubber bodies 10 and 11, respectively. It is attached to the vehicle body 1 via the first and second mount rubber bodies 10 and 11 so as to support the front end of the differential gear case 4 on the vehicle body 1 at two opposite points on the left and right sides thereof. It is provided.

Further, a third mount rubber body 14 having a cylindrical shape and having a center hole 13 is provided on the upper surface of the substantially central portion of the rear end portion of the differential gear case 4 via a support bracket 12. The third mount rubber body 1 is fixed in alignment with the axial direction (front-back direction) of the propeller shaft 2.
A rear support member 16 having a U-shaped cross section and arranged in the left-right direction of the vehicle body 1 is fixed to the rear support member 16 at the intermediate portion of the rear support member 16 through a support bolt 15 that is inserted into and fixed to the center hole 13 of the rear support member 4. Support member 16
The left and right tips of the differential gear case 4 are attached to the vehicle body 1, and the rear end of the differential gear case 4 is connected to the vehicle body 1 via a third mount rubber body 14 that is disposed directly above the rear end of the differential gear case 4 at one point in its approximate center. It is set up to support.

Furthermore, when attaching the rear support member 16 to the support bolt 15 that is inserted and fixed into the center hole 13 of the third mount rubber body 14, the third mount rubber body 14 is configured such that both ends of the rear support member 16 are not attached to the vehicle body 1. By tilting the propeller shaft 2 from the horizontal position by a predetermined angle θ in the direction opposite to the forward rotational direction of the propeller shaft 2, both ends of the rear support member 16 are attached to the vehicle body 1 (the rear support member 16 is not horizontal). 4), a predetermined initial torsional stress T is applied around the center hole 13 (as shown in FIG _{. 1} and the transverse elastic modulus is G, then T=4πGlθ/1/r ₁ ² -1/r ² ₂
)) is provided. This initial torsional stress T is the third torsional stress generated in the differential gear case 4 by the forward driving force of the propeller shaft 2 within the normal acceleration range when the automobile is traveling forward.
The direction and size are set to offset the moment around the mount rubber body 14. Furthermore, 1
7 and 17 are a pair of Y-shaped wheels whose front ends are rotatably supported on the left and right sides of the front support member 9 via brackets 18 and 18, and whose rear ends are fixed to the wheel bearings 7. suspension arm, each rotation axis being at the vehicle body 1.
The coil spring 5 is inclined with respect to the axis of the drive shaft 5 so as to face the center of the drive shaft 5, and supports a coil spring (not shown).

Therefore, in the above embodiment, when the automobile accelerates while traveling forward, the forward driving force of the propeller shaft 2 causes the differential gear case to rotate in the same direction as the forward rotational direction of the propeller shaft 2. A moment is generated around the third mount rubber body 14, but since the third mount rubber body 14 has been given an initial torsional stress T in a direction that offsets the moment, the moment is generated as shown in FIG. initial torsional stress T
The first and second
The amount of deformation of each of the mount rubber bodies 10 and 11 is approximately the same, and the vehicle body 1 can be maintained in a normal state and run without being tilted in the left-right direction. Moreover, since the third mount rubber body 14 is located directly above the approximate center of the rear end of the differential gear case 4 and on the axis of the propeller shaft 2, the differential gear case 4 is Even if the third mount rubber body 14 moves in this direction, no unnecessary moment is generated around the third mount rubber body 14, and the above-mentioned vibration absorption can be carried out smoothly.

Further, the application of the initial torsional stress T to the third mount rubber body 14 causes the rear support member 16 to be attached to the center hole 13 of the third mount rubber body 14
The rear support member 16 can be easily obtained by attaching the rear support member 16 to the vehicle body 1 in a horizontal position after attaching it to the support bolt 15 which has been inserted and secured in advance at a predetermined angle θ from a horizontal position. This can be done efficiently using existing parts without increasing the number of parts.

In addition, in the above embodiment, the third mount rubber body 1
4 is attached to the middle part of the rear support member 16 via the support bolt 15 that is inserted into the center hole 13 and fixed, and both ends of the rear support member 16 are attached to the vehicle body 1. The third mount rubber body may be directly attached to the vehicle body while applying an initial torsional stress.
Also, instead of attaching the outer periphery of the third mount rubber body and the support bolts to the differential gear case side and the vehicle body side, respectively, it is possible to attach them to the vehicle body side and the differential gear case side, respectively, in the same manner as in the above embodiment. It is possible to achieve the following effects.

Furthermore, the support device of the present invention can be applied not only to a semi-trailing arm type independent suspension type suspension device as in the above embodiment, but also to a trailing arm type independent suspension type suspension device. Of course.

In addition, the above-mentioned effect of the present invention is effective when moving forward, but not when moving backward, but the frequency of moving backward compared to moving forward is very low.
This can be ignored in practical terms.

As described above, according to the present invention, two opposite points on the left and right sides of the front end of the differential gear case are supported on the vehicle body via the first and second mount rubber bodies, respectively, and the differential gear case is supported on the vehicle body via the first and second mount rubber bodies. A support device for a differential gear case in which a single point substantially in the center of the rear end of the gear case is supported on the vehicle body via a third mount rubber body disposed directly above the point, wherein the third mount rubber body The body is composed of a cylindrical rubber body, the central axis of which is arranged in a direction that coincides with the axis of the propeller shaft, and this rubber body is provided with a predetermined above-mentioned shape in a direction that offsets the moment generated by the forward driving force of the propeller shaft. By applying an initial torsional stress around the center axis, it is possible to maintain a simple structure without requiring any separate parts, and generate unnecessary moments around the third mount rubber body when the differential gear case moves in the vertical direction. Since it is possible to reduce or offset the moment generated by the forward driving force of the propeller shaft when the vehicle is accelerating forward, it is possible to improve running stability and steering performance when the vehicle is accelerating forward. This makes it possible to reduce the cost of the device.

Furthermore, approximately the center of the rear end of the differential gear case is connected to the rear end of the differential gear case through a third mount rubber body.
By connecting it to the rear support member attached to the vehicle body, there is an advantage that the initial torsional stress can be applied to the third mount rubber body at the same time as the rear support member is attached to the vehicle body and with good workability. It is something that you have.

[Brief explanation of the drawing]

The drawings illustrate an embodiment of the present invention, and FIG. 1 is a plan view, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG.
FIG. 3 is a schematic explanatory view showing the state of stress acting on the rear support member, and FIG. 4 is an enlarged sectional view of the third mount rubber body. 1...Vehicle body, 2...Propeller shaft, 3...
Foot joint, 4...Differential gear case, 5...Drive shaft, 6...Constant velocity joint, 7...Wheel bearing, 8...Rear tire,
9... Front support member, 10... First mount rubber body, 11... Second mount rubber body, 12... Support bracket, 13... Center hole,
14... Third mount rubber body, 15... Support bolt, 16... Rear support member, 17... Suspension arm, 18... Bracket.

Claims (1)

[Claims for Utility Model Registration] (1) Two opposite points on the left and right sides of the front end of the differential gear case are the first and second points, respectively.
It is supported on the vehicle body via a mount rubber body, and also supported on the vehicle body through a third mount rubber body disposed at a substantially central point of the rear end portion of the differential gear case. In the support device for a differential gear case, the third mount rubber body is composed of a cylindrical rubber body, the central axis of which is arranged in a direction that coincides with the axis of the propeller shaft, and the propeller is attached to this rubber body. A support device for a differential gear case, characterized in that an initial torsional stress is applied about a predetermined central axis in a direction that offsets a moment generated by a forward driving force of a shaft. (2) The scope of the utility model registration claim, characterized in that approximately the center of the rear end of the differential gear case is connected to and supported by a rear support member attached to the vehicle body via a third mount rubber body. A support device for a differential gear case as described in paragraph (1).