JPH0649405B2 - Rear suspension device for automobile - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a rear suspension device mounted on an FR (front engine / rear drive) type automobile.

(Prior Art) Conventionally, as a rear suspension device for an automobile of this type, as disclosed in, for example, Japanese Utility Model Publication No. 50-15288, a suspension that is arranged in the vehicle width direction and elastically supported by the vehicle body at both ends is provided. A mount frame, one end rotatably connected to the suspension mount frame, a pair of left and right rear suspension arms supporting the rear wheels at the other end, and a differential device for transmitting power to the rear wheels are built-in. It is known that a front portion is connected to the suspension mount frame near the center thereof and a rear portion is provided with a differential case elastically supported by the vehicle body.

(Problems to be Solved by the Invention) In such a rear suspension device, the suspension mount frame is elastically supported on the vehicle body because the rear suspension arm and the differential case are connected to the suspension mount frame. For the rigidity of the rubber member, there are the following two conflicting requirements. That is, in order to prevent the vibration generated from the differential case from being transmitted to the vehicle body through the suspension mount frame, it is necessary to soften the rigidity of the rubber member, while the suspension is generated when an external force is applied to the rear wheels. In order to firmly support the rear wheel by the arm and ensure traveling stability, it is necessary to make the rubber member rigid.

For this reason, conventionally, the rigidity of the rubber member has been set as a harmonization point between the two contradictory requirements, but the reality is that neither requirement can be sufficiently satisfied. In particular, when rapid vibration occurs in the differential case such as during sudden start, the front portion of the differential case is connected to the central portion of the suspension mount frame, so the suspension mount frame moves up and down. There is a problem that the vertical movement of the suspension mount frame causes a vibration of the vehicle body to significantly reduce the riding comfort, and the vibration transmission to the rear suspension arm causes an adverse effect such as unstable suspension characteristics.

In a large automobile such as a truck, the front and rear parts of the differential case are elastically supported by the vehicle body through cross members, while the left and right rear suspension arms are connected to the vehicle body independently of the differential case. (See Japanese Patent Publication No. 58-24290). In the case of this configuration, the above-mentioned problem does not occur, but in a small automobile such as a passenger car, such a configuration cannot be adopted in view of the vehicle width regulation and the like.

The present invention has been made in view of the above problems, and an object thereof is to improve the structure of the connecting portion between the differential case and the vehicle body as described above to effectively reduce the vehicle body vibration and improve the running stability. To get it.

(Means for Solving the Problems) In order to achieve the above object, a solution means of the present invention is a suspension mount frame which is arranged in the vehicle width direction and elastically supported by the vehicle body at both ends, and one end of the suspension mount frame. A pair of left and right rear suspension arms that are rotatably connected to each other and support the rear wheels at the other end, and a differential device that is arranged behind the suspension mount frame and that transmits the power of the rear wheels. In the rear suspension device of an automobile including the differential case, the front portion of the differential case is connected to the vicinity of the center of the suspension mount frame, and the rear portion is elastically supported by the vehicle body. The center portion of the suspension mount frame is connected to the vehicle body through a vertical movement restraining member that restrains the vertical movement of the central portion, and the input displacement speed is increased between the rear portion of the differential case and the vehicle body. The oil-filled rubber is set so that the resistance force that suppresses the displacement increases in accordance with the above.

(Operation) With the above configuration, according to the present invention, even if the rigidity of the rubber member for elastically supporting the suspension mount frame on the vehicle body is increased in order to ensure traveling stability, the vibration of the differential case is transmitted to the vehicle body. Vertical motion transmitted from the front side of the differential case to the suspension mount frame is suppressed to a minimum vibration by a separate vertical motion suppression member,
By positively changing the vibration characteristics input from the rear side of the differential case with oil-filled rubber, the total vertical movement of the front side and rear side of the differential case can be minimized. The resonance between the vertical movement on the front side and the vertical movement on the rear side can be suppressed, and as a result, the vibration transmitted to the vehicle body can be minimized. Therefore, it is possible to effectively prevent the vibration of the differential case from being transmitted to the vehicle body while ensuring traveling stability.

(Example) Hereinafter, the Example of this invention is described based on drawing.

1 to 3 show a rear suspension device for an FR type automobile as an embodiment of the present invention, in which 1 is a suspension mount frame arranged in the vehicle width direction, and both ends of the suspension mount frame 1 are , A main frame (not shown) which is a strength member of the vehicle body via the rubber portions 2 and 2, respectively.
It is elastically supported by. Each rubber member 2 is an inner cylinder 2
An elastic body 2c such as rubber is filled and fixed between a and the outer cylinder 2b. Reference numerals 3 and 3 denote a pair of left and right rear suspension arms which are arranged in the vehicle front-rear direction at the rear of both ends of the suspension mount frame 1. Each of the rear suspension arms 3 includes two arm members 4 and 4 and a wheel. It is formed into a bifurcated shape by connecting the supporting member 5 to the front and rear. The front and rear portions of the arm members 4 and 4 of the rear suspension arm 3 are the suspension mount frame 1 respectively.
While being rotatably connected to the wheel support member 5,
A rear wheel 6 is rotatably supported on the.

Reference numeral 7 denotes a differential case arranged in the rear of the central portion of the suspension mount frame 1. Inside the differential case 7, an engine driving force input through a propeller shaft (not shown) is input to the drive shaft. A differential device is provided for transmitting to the left and right rear wheels 6, 6 via.

The front portion of the differential case 7 extends above the central portion of the suspension mount frame 1 and is connected to the suspension mount frame 1 via a rubber member 8. The rubber member 8 is the differential case 7.
A case bracket 9 attached to one side surface of the front portion (on the left side of the vehicle in the figure) and a frame bracket attached to the central portion of the suspension mount frame 1 and facing the case bracket 9 with a predetermined gap in the vehicle width direction. 10 and both brackets 9 and 10 have both end faces between the brackets 9,
Elastic body 11 made of rubber or the like fixedly provided on
The front part of the differential case 7 is elastically supported on the suspension mount frame 1.

On the other hand, a cross member 12 extending in the vehicle width direction is connected to the upper surface of the rear part of the differential case 7 at the center in the longitudinal direction, and both ends of the cross member 12 are respectively provided with oil-filled rubber members 13, 13. It is elastically supported by the main frame of the vehicle body. As shown in FIG. 4, the oil-filled type rubber member 13 has two oil chambers 14, a first and a second oil chamber 14 in which oil is filled up and down.
15, the upper first oil chamber 14 has its peripheral wall formed of rubber 16, while the lower second oil chamber 15 has its bottom wall formed of rubber 17, and The volumes of the chambers 14 and 15 are variable. Also, the first
The oil chamber 14 and the second oil chamber 15 are the second oil chamber 1
5, the fitting groove 19 is integrally extended from the upper end portion of the metal plate 18 forming the peripheral wall inwardly, and the fitting groove 19 is formed at the inner peripheral edge thereof. A movable plate 2 having an orifice 20 in the center of the groove 19
1 is movably fitted vertically so as to form a communication passage 22 that connects the first oil chamber 14 and the second oil chamber 15 to each other. Then, when the differential case 7 is gently oscillated and displaced, the first oil chamber 14 and the second oil chamber 15 communicate with each other through the communication passage 22 and the orifice 20, so that the resistance force for suppressing the oscillating displacement is increased. While it occurs only slightly along the line A in FIG. 5 and originally functions as a rubber member, when the differential case 7 is rapidly vibrated and displaced, the movable plate 21 is fitted into the fitting groove 19.
The communication passage 22 is closed closely to the upper and lower surfaces, and the first oil chamber 14 and the second oil chamber 15 communicate with each other only via the orifice 20, so that the resistance force is along the line B in FIG. It occurs largely and is designed to function as a resistance device such as a damper.

In addition, an extension portion 23 extending rearward from the attachment portion of the frame bracket 10 along the side of the differential case 7 is formed in the central portion of the suspension mount frame 1, and the extension portion 23 is provided. A link member 24 as a vertical motion suppressing member extending in the vertical direction near the tip of the
Are arranged. The link member 24 has a lower end portion connected to the tip of the extending portion 23 and an upper end portion connected to the vehicle body via elastic bushes 25a and 25b, respectively, to suppress vertical movement of the central portion of the suspension mount frame 1. The rotational displacement around the axis connecting both ends of the suspension mount frame 1 is restricted.

Here, the rubber members 2, 2 at both ends of the suspension mount frame 1 as elastic support points of the suspension mount frame 1
And elastic bushes 25 at both ends of the link member 24.
The rigidity (elastic strength) of each of a and 25b is set to be hard from the viewpoint of ensuring running stability. On the other hand, the functional structure as a rubber member in the oil-filled rubber members 13, 13 at both ends of the cross member 12 as elastic supporting points of the differential case 7 (characteristic of line A in FIG. 5) and the rubber at the front of the differential case 7. The rigidity of each member 8 is set to be low from the viewpoint of suppressing vehicle body vibration.

Further, 26 is the extension portion 2 of the suspension mount frame 1.
3 and the differential case 7, which are arranged in an upward direction, the upper end of the damper 26 is connected to the center of the link member 24,
The lower end is connected to the lower side surface of the differential case 7. The damper 26 is configured in the same manner as a conventionally known damper for vibration damping, and operates in the same manner as the oil-filled rubber member 13, that is, when the differential case 7 gently vibrates, the vibration displacement is suppressed. A slight resistance force is generated along the line A in FIG. 5, and a large resistance force is generated along the line B in FIG. 5 when the differential case 7 is rapidly vibrated and displaced.

Therefore, in the above-described embodiment, the rear portion of the differential case 7 is connected to the vehicle body (main frame) via the oil-filled rubber members 13 and 13 which have both a function as a rubber member and a function as a resistance device. Thus, when the differential case 7 vibrates gently during normal operation, the function of the oil-filled rubber member 13 as a rubber member absorbs the vibration of the differential case 7 to the vehicle body directly or via the suspension mount frame 1. Vibration can be prevented from being transmitted. Further, when the differential case 7 is rapidly vibrated and displaced due to a sudden start or the like, the oil-filled rubber member 13 is used.
With the large resistance force of the function as the resistance device, the vibration of the differential case 7 can be suppressed from being attenuated and the vibration can be prevented from being transmitted to the vehicle body directly or via the suspension mount frame 1. Therefore, when the rigidity of the rubber members 2 and 2 at both ends of the suspension mount frame 1 and the elastic bushes 25a and 25b at both ends of the link member 24 as elastic support points of the suspension mount frame 1 is increased to ensure running stability. However, the vibration of the differential case 7 is not transmitted to the vehicle body directly or via the suspension mount frame 1, so that it is possible to effectively improve the traveling stability and reduce the vehicle body vibration.

Moreover, as described above, even when the differential case 7 is rapidly vibrating, the vibration accompanying the differential case 7 of the suspension mount frame 1 can be effectively suppressed by the function of the oil-filled rubber member 13 as a resistance device. The transmission of vibrations from the mount frame 1 to the rear suspension arm 3 does not adversely affect the suspension characteristics, and the running stability can be further improved.

In this case, the transmission of the vibration of the differential case 7 to the vehicle body is minimized by the separate link member 24 (vertical movement suppressing member) from the vertical movement transmitted from the front side of the differential case 7 to the suspension mount frame 1. While suppressing the vibration of the differential case 7, the vibration characteristic input from the rear side of the differential case 7 is positively changed by the oil-filled rubber member 13 to move up and down on the front side and up and down on the rear side of the differential case 7. By minimizing the total movement of the above, the resonance between the vertical movement on the front side and the vertical movement on the rear side can be suppressed, and as a result, the vibration transmitted to the vehicle body can be minimized.

Further, in the above embodiment, the front portion of the differential case 7 is connected to the suspension mount frame 1 via the rubber member 8, and the damper 26 is provided between the differential case 7 and the suspension mount frame 1. In cooperation with the oil-filled rubber member 13 described above, when the differential case 7 is gently vibrating during normal operation, the rubber member 8 more effectively absorbs the vibration of the differential case 7 and the suspension mount frame 1 Vibration can be prevented from being transmitted to the suspension mount frame 1. Further, when the differential case 7 is rapidly vibrated when it is suddenly started, the damper 26 damps the vibration of the differential case 7 more effectively and suppresses the vibration to the suspension mount frame 1. Can be prevented from being transmitted, resulting in improved running stability and It is possible to achieve a reduction of more and more effective.

In the above embodiment, the oil-filled rubber member 13 having both the function as a rubber member and the function as a resistance device is provided between the differential case 7 and the vehicle body. It goes without saying that an oil-filled rubber which is set so as to increase the resistance force for suppressing the displacement in accordance with the increase of the displacement speed of the input may be provided independently of the rubber member for supporting.
However, the oil-filled rubber member 13 as in the above embodiment is used.
In the case of (2), both can be integrated, which is preferable in terms of simplification of the structure.

(Effects of the Invention) As described above, according to the automobile rear suspension device of the present invention, the vertical movement suppressing member for suppressing the vertical movement of the central portion of the suspension mount frame to which the front portion of the differential case is connected. While the rear portion of the differential case is elastically supported by the vehicle body while being connected to the vehicle body via the vehicle, a resistance force that suppresses the displacement according to the increase of the input displacement speed is provided between the rear portion of the differential case and the vehicle body. By providing the oil-filled rubber set to increase, it is possible to effectively prevent both the gentle vibration and the rapid vibration of the differential case from being transmitted to the vehicle body, and the front side of the differential case. The total movement of the vertical movement of the vehicle and the vertical movement of the rear side can be minimized to suppress the resonance between the two and be transmitted to the vehicle body. Since the vibration can be minimized, the vibration of the vehicle body can be reduced, and the suspension characteristics can be stabilized to effectively improve the running stability.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a plan view,
2 is a front view, FIG. 3 is a side view, FIG. 4 is a sectional view of an oil-filled rubber member, and FIG. 5 is a diagram showing characteristics of the oil-filled rubber member. 1 ... Susmount frame, 3 ... Rear suspension arm, 6 ... Rear wheel, 7 ... Differential case, 13 ...
Oil-filled rubber member, 24 ... Link member.

Claims (1)

[Claims] 1. A suspension mount frame, which is disposed in the vehicle width direction and whose both ends are elastically supported by the vehicle body, and one end which is rotatably connected to the suspension mount frame at one end and supports rear wheels at the other end. A rear suspension device for an automobile, comprising a pair of rear suspension arms and a differential case that is disposed behind the suspension mount frame and has a differential device for transmitting power to the rear wheels. The front portion is connected to the vicinity of the center of the suspension mount frame, and the rear portion is elastically supported by the vehicle body, and the center portion of the suspension mount frame is attached to the vehicle body via a vertical movement suppressing member that suppresses vertical movement of the central portion. It is connected, and between the rear part of the differential case and the vehicle body,
A rear suspension device for an automobile, comprising: an oil-filled rubber set so that a resistance force that suppresses the displacement increases as the input displacement speed increases.