JPH0669773B2 - Vehicle rear suspension device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in the structure of a rear suspension device of a vehicle mounted on a vehicle such as an automobile.

[Conventional technology]

Generally, as a rear suspension device of a vehicle such as an automobile, for example, a device disclosed in Japanese Patent Publication No. 60-42041 is known. This is a longitudinal stay (front link arm) having one end connected to the vehicle body side and the other end attached to the wheel side, and one end side rotatably attached to the vehicle body at a position rearward of the longitudinal stay. , Lateral stay with the other end attached to the wheel side (rear link arm)
Respectively, the lateral stays are formed by elastic members such as leaf springs, and a swivel support is disposed between the longitudinal stays and the vehicle body side. One end side of the swivel support body is rotated to the vehicle body side. It is movably mounted and hinged between the other end of the swivel bearing and the longitudinal stay via a pin that forms a vertical swivel axis. In this case, a cylindrical sleeve is formed on the longitudinal stay, and a bush formed by an elastic body is arranged between the sleeve and the swivel support. further,
The bush has a notch extending horizontally.

Then, when a braking force is applied to the rear wheels, a reaction force in the direction opposite to the traveling direction is applied to the longitudinal stays, and this reaction force causes the swivel bearing body to face inward about the pin that forms the swivel axis. The rear wheel is swung in the toe-in direction via the longitudinal stay in accordance with the turning motion of the swivel bearing, thereby compensating for the toe-out direction deviation acting on the rear wheel by the braking force. There is.
In this case, the toe change of the rear wheel is performed according to the amount of bending of the lateral stay formed by the leaf spring, and the lateral stay is in the normal position when the leaf spring is not deformed. .

[Problems to be solved by the invention]

In general, when the vehicle body is turning (during cornering), an external force (lateral force) is applied to the rear wheel on the outer wheel side from the lateral direction, and this lateral force must be received by the lateral stay. However, in the above-mentioned conventional structure, since the lateral stay is formed by an elastic member such as a leaf spring, the plate thickness of the leaf spring cannot be reduced due to the buckling strength of the lateral stay. was there. Therefore, since the plate spring of the lateral stay tends to be relatively thick, there is a problem that a relatively large force is required when elastically deforming the plate spring of the lateral stay. If a large force is required for elastic deformation of the leaf spring of the lateral stay, the leaf spring of the lateral stay is caused by the lateral force when the lateral force acts on the rear wheel on the outer wheel side during turning of the vehicle body. Since it becomes difficult to elastically deform the vehicle, it is difficult to obtain the toe-in effect on the rear wheel on the outer wheel side, and the vehicle tends to oversteer, and at the same time, only a small amount of toe-in operation is obtained.
That is, since the rear wheels do not toe-in unless a relatively large braking force is applied, it is difficult to obtain a desired toe-in operation when turning while braking lightly. In such a case, the steering characteristic is oversteered. There was a disadvantage that the running stability of the vehicle was easily impaired.

Furthermore, in the above-mentioned conventional example, since another horizontal stay that supports the wheel support member is provided above the lateral stay,
When the lateral stays are elastically deformed, the longitudinal stays that support the wheel support members below are displaced to the inside of the vehicle body and the wheel support members are tilted to the outside of the vehicle body, causing a camber change and a large change in alignment characteristics. there were.
In addition, there is a drawback in that there are many design difficulties in order to suppress such an inconvenience to the extent that practicality is not impaired, and at the same time, there is a problem that the structure is complicated and high-precision processing is required.

Further, in the above-mentioned conventional example, the instantaneous center point defined by the intersection of the extension line passing through both ends of the turning support and the extension line of the lateral stay in the horizontal plane of the vehicle body is located in front of the rear wheel axle. Therefore, when a lateral force inward in the vehicle width direction is applied to the rear wheel that is the outer wheel side when the vehicle turns, a force that displaces the rear wheel in the toe-out direction due to the moment around the instantaneous center point acts on the vehicle. There was a problem that the tendency was likely to occur.

The present invention has been made in view of the above problems, and even if a lateral force acts on the rear wheel on the outer wheel side during the turning operation of the vehicle body, the toe-in effect can be obtained on the rear wheel on the outer wheel side.
It is an object of the present invention to provide a rear suspension device for a vehicle, which can generate an understeer tendency in the vehicle to improve the turning performance and safety and can be downsized as a whole.

[Means for solving problems]

According to the present invention, a trailing arm which is arranged substantially in the front-rear direction of a vehicle and rotatably supports a rear wheel at a rear portion, and an outer end portion which is arranged substantially in the vehicle width direction and whose outer end portion is pivotally attached to the rear portion of the trailing arm and whose inner end portion In a rear suspension device for a vehicle having a pair of upper and lower lateral arms pivotally mounted on a vehicle body side, the trailing arm includes a vehicle body side arm having one end pivotally mounted on the vehicle body side and the two lateral arms on a rear portion. Is divided into a wheel-side arm having a pivotally-attached portion and a rear wheel rotation support portion, and the axial direction is substantially between the other end of the vehicle-body-side arm and the front portion of the wheel-side arm. While rotatably connecting around a rotation axis arranged in the vertical direction, the one end of the vehicle body side arm is arranged inside the vehicle width direction with respect to the other end, and in the vehicle body horizontal plane, Both the body side arm Extension and the two through the pivot point center
The center line between the two extension lines passing through the centers of the pivotal portions at the inner and outer ends of each of the lateral arms intersects behind the center of the rear wheel and outward in the vehicle width direction, and the side surface of the vehicle body. In the visual observation, the arms are arranged so that a straight line connecting the centers of the pivot parts at the outer ends of the upper and lower lateral arms intersects with the road surface behind the ground contact center of the rear wheel.

[Action]

A trailing arm configured by being divided into a vehicle body side arm and a wheel side arm and a lateral arm constitute a 4-node link which is easily deformed in the vehicle body horizontal plane.
The rear wheel is rotatably supported by the wheel-side arm located in the middle of the link of the joint, so that the link of the fourth joint is easily deformed by the force acting on the rear wheel from the road surface side, and the toe change is generated in the rear wheel.

Further, the vertical stroke of the rear wheel is achieved by the rotational displacement of the trailing arm and the lateral arm with respect to the vehicle body and the relative rotational displacement between the trailing arm and the lateral arm, and in order to achieve this vertical stroke. All joint points of are used as joint points for generating toe change.

Furthermore, in the horizontal plane of the vehicle body, an extension line passing through the center of both ends of the arm on the vehicle body side and an extension line passing through the center of both ends of the lateral arm inside and outside of the lateral arm may intersect behind the center of the rear wheel and outside in the vehicle width direction. By placing each arm, 4
The instantaneous center point of the rear wheel displacement in the horizontal plane of the vehicle body defined by the links of the joints is located rearward of the rear wheel center and outside in the vehicle width direction, and the vehicle body side of the vehicle body foam arm with respect to the wheel side arm side. By arranging them in the vehicle width direction inside, when a rearward force is applied to the rear wheel during braking, the rotational moment force acts around the instantaneous center point outside the center of the rear wheel, and the four-node ring is deformed. Works toe-in. Also, when a force is applied to the rear wheel inward in the vehicle width direction during turning, a rotational moment around the instantaneous center point behind the center of the rear wheel acts and the 4-bar link is deformed. Toe-in works.

Further, in a side view of the vehicle body, by arranging the straight line connecting the centers of the pivot parts at the outer ends of the upper and lower two lateral arms so as to intersect the road surface behind the ground contact center of the rear wheel, the rear wheel can be used when turning. The rear wheels are toe-in actuated by a moment force around a straight line generated against the inward force acting on the vehicle.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.
1 and 2 show a schematic configuration of a main part of a rear suspension device of a vehicle such as an automobile. 1 is a tire of a rear wheel, 2 is a propeller shaft on a vehicle body side, 3 is a body frame, 4 is a It is a suspension cross member.
The suspension cross member 4 is arranged along the vehicle width direction, and is mounted in a erected state between a pair of body frames 3 arranged on the left and right of the vehicle body. further,
The suspension cross member 4 is bent and formed with its central portion side curved toward the rear side of the vehicle body. In this case, the suspension cross member 4 is attached to the body frame 3 side via a cross member bush 5 formed of an elastic body.

6 is a trailing arm for supporting the rear wheels, 7a, 7b
Is a pair of upper and lower lateral arms (upper link 7a and lower link 7b). The trailing arm 6 is divided into an additional link (vehicle body side arm) 8 pivotally attached to the vehicle body side and a trailing link (wheel side arm) 9 connected to the rear wheel side. In this case, the additional link 8 is arranged inside the trailing link 9 in the vehicle width direction. Further, a cylindrical portion 10 is formed at the front end of the trailing link 9 as shown in FIG. 3, and the tip end side of the rod-shaped additional link 8 is inserted into the cylindrical portion 10. The base end side of the additional link 8 is elastically pivotally attached to the suspension cross member 4 via a bush formed of an elastic body. A rotating shaft 11 is attached in a penetrating state between the tip end side of these additional links 8 and the cylindrical portion 10 of the trailing link 9. The rotary shaft 11 is arranged such that its axial center direction is substantially vertical, and the tip end side of the additional link 8 and the trailing link 9 are arranged.
It is connected to the cylindrical portion 10 so as to be rotatable around a rotation shaft 11. Further, a bush 12 formed of an elastic body is interposed between the cylindrical portion 10 of the trailing link 9 and the tip end side of the additional link 8. The bush 12 is formed with a pair of notches 12a and 12b on both sides. With the deformation of the bush 12, the relative movement between the trailing link 9 and the additional link 8 around the pivot shaft 11 is formed. It is possible to perform various turning operations. A substantially cylindrical axle housing 13 and a hub carrier 14 fitted to the outer peripheral surface of the axle housing 13 are integrally fixed to the rear end of the trailing link 9 by means such as welding. This hub carrier
An upper support portion 15 that pivotally supports the upper link 7a of the lateral arm is formed at the upper portion of 14, and a lower support portion 16 that pivotally supports the lower link 7b of the lateral arm is formed at the lower portion of the hub carrier 14. There is.

Further, the outer end of the upper link 7a of the lateral arm is ball-jointed to the upper support portion 15 of the hub carrier 14.
The inner end portion of the suspension cross member 4 on the vehicle body side is elastically pivoted via a bush formed of an elastic body at a portion near the rearward projecting portion 4a of the curved portion. Has been done. Similarly to the upper link 7a, the lower link 7b of the lateral arm has an outer end pivotally attached to the lower support portion 16 of the hub carrier 14 via a ball joint 16a, and an inner end portion of the suspension cross on the vehicle body side. The member 4 is elastically pivotally attached to the vicinity of the rearward projecting portion 4a at the tip of the curved portion of the member 4 via a bush formed of an elastic body. In this case, the connecting portion between the upper link 7a and the lower link 7b of the lateral arm and the suspension cross member 4 on the vehicle body side is more than the connecting portion between the upper link 7a and the lower link 7b of the lateral arm and the trailing link 9 side. It is located on the front side of the vehicle body. Then, the additional link 8, trailing link 9 and lateral arm (upper link 7a and trailing link 9) of these trailing arms 6 constitute a four-section link as shown in FIG. 4 and FIG. There is. further,
The connecting portion between the upper link 7a of the lateral arm and the trailing link 9 side is arranged on the front side of the vehicle body with respect to the connecting portion between the lower link 7b of the lateral arm and the trailing link 9 side, and inward in the vehicle width direction. It is arranged. Further, a shock absorber bracket is formed at the rear end of the trailing link 9, and the lower end of the strut type shock absorber 17 is connected to the shock absorber bracket.

On the other hand, a differential device 18 is attached to the rear protruding portion 4a at the tip of the curved portion of the suspension cross member 4. A rear end portion of the differential device 18 is supported by a differential support member 19 mounted between the left and right body frames 3 and 3 in an installed state. Further, the diff support member 19 is elastically connected to the body frame 3 side via a diff support member bush 20 formed of an elastic body. Reference numeral 21 is a drive shaft, and 22 is a rear wheel spindle.

Therefore, in the above-mentioned structure, the trailing arm 6 is provided with the trailing link 8, the trailing link 9 and the lateral arm (upper link 7a and trailing link 9) as shown in FIGS. 4 and 5. The rear wheel spindle 22 is caused by the relative rotation between the trailing link 9 and the additional link 8 about the rotation shaft 11 that connects the additional link 8 and the trailing link 9 of the arm 6.
Since the four-section link for moving the position of the rear wheel to change the toe of the rear wheel is constructed, when a rearward force is applied to the vehicle body such as during braking operation, the trailing link 9 is applied by the rearward force. And the additional link 8 are rotated relative to each other about the rotation shaft 11,
With this pivoting operation, the link can be deformed from the normal position shown by the solid line in FIG. 5 to the toe-in position shown by the phantom line in FIG. 5 to make the toe change of the rear wheels.

Further, the connecting portion between the upper link 7a and the lower link 7b of the lateral arm and the suspension cross member 4 on the vehicle body side should be closer to the vehicle body than the connecting portion between the upper link 7a and the lower link 7b of the lateral arm and the trailing link 9 side. Since it is arranged on the front side, the center line O ₁ of the additional link 8 of the trailing arm 6 and the center line of the lateral arm (the center line O ₃ of the upper link 7a and the lower link 7b).
The instantaneous center P of the suspension arm which is formed by the intersection of the center line) O ₂ between the center line O ₄ at the rear side of the axle, and can be easily set in the vehicle width direction outer side than the rear wheel center. For this reason, a toe change occurs with respect to the force acting on the rear wheels due to the moment force around the instantaneous center point P, and the toe-in operation during braking described above is performed with the instantaneous center point P from the center of the rear wheels in the vehicle width direction. This is due to the inner moment generated from being located outside. Further, for example, when a lateral force acts on the rear wheel on the outer wheel side from the outside as indicated by an arrow F in FIG. 1 during the turning operation of the vehicle body, the moment force about the instantaneous center point P generated by the lateral force is generated. Rotation axis between trailing link 9 and additional link 8
When relative rotation centering on 11 is performed and the link is deformed with this rotation toe-in effect on the rear wheel on the outer wheel side and lateral force is applied to the rear wheel on the inner wheel from the inside. Since the toe-out effect can be provided to the rear wheels on the inner wheel side, the understeer tendency can be reliably generated in the vehicle during the turning operation of the vehicle body. Therefore, it is possible to improve the turning performance and safety of the vehicle during the turning operation of the vehicle body.

Further, the connecting portion between the upper link 7a and the lower link 7b of the lateral arm and the suspension cross member 4 on the vehicle body side should be closer to the vehicle body than the connecting portion between the upper link 7a and the lower link 7b of the lateral arm and the trailing link 9 side. Placed on the front side, lateral link upper link
Since the 7a and the lower link 7b are arranged obliquely with respect to the vehicle width direction, it is possible to reduce the size of the entire rear suspension device as compared with the case where these are arranged in the vehicle width direction.

Furthermore, the base end side of the additional link 8 of the trailing arm 6 is elastically pivoted to the suspension cross member 4 via a bush formed of an elastic body, and the upper link 7a and the lower link 7b of the lateral arm are connected. Since the inner end portion is elastically pivotally attached to a portion of the suspension cross member 4 in the vicinity of the rearward projecting portion 4a at the tip of the curved portion of the suspension cross member 4 via a bush formed of an elastic body, the suspension cross member 4 is attached to the body frame 3
The rear suspension device can be mounted on the suspension cross member 4 before mounting on the side. Therefore, the workability of assembling the vehicle body can be improved. Further, since the central portion side of the suspension cross member 4 is curved to the rear side of the vehicle body, the rear protruding portion 4a at the tip of the curved portion of the suspension cross member 4 is bent.
It is also possible to improve the workability when the differential device 18 is mounted on the.

Further, as shown in FIG. 6, in a side view of the vehicle body, a straight line connecting the centers of the pivotal joints at the outer ends of the upper link 7a and the lower link 7b of the upper and lower lateral arms is located behind the ground contact center of the rear wheel. Since it was placed so that it intersects the road surface at the point,
The rear wheels can also be toe-in actuated by a moment force around a straight line generated against a force applied to the rear wheels inward in the vehicle width direction during turning.

The present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

〔The invention's effect〕

According to the present invention, the trailing arm, which is divided into the vehicle body side arm and the wheel side arm, and the lateral arm constitute a 4-section link that is easily deformed in the horizontal plane of the body. Since the rear wheel is rotatably supported by the wheel side arm located in the middle, the link of the above-mentioned 4th node can be easily deformed by the force acting on the rear wheel from the road surface side, and the toe change can be generated in the rear wheel. .

Also, the vertical stroke of the rear wheel is achieved by the rotational displacement of the trailing arm and the lateral arm with respect to the vehicle body and the relative rotational displacement between the trailing arm and the lateral arm. All the joint points to achieve are used as the joint points to generate the toe change. In other words, the rear suspension of the present application realizes a toe change only by providing one joint point between the vehicle body side arm and the wheel side arm in addition to each joint point for achieving the vertical stroke. However, there is an advantage that a toe change can be easily generated with a simple configuration.

In particular, in the horizontal plane of the vehicle body, the extension line passing through the center of both ends of the arm on the vehicle body side and the extension line passing through the center of both ends of the lateral arm inside and outside of the lateral arm should intersect behind the center of the rear wheel and outside in the vehicle width direction. Since each arm is arranged in the vehicle, the instantaneous center point of the displacement of the rear wheel in the horizontal plane of the vehicle body defined by the link of Section 4 is located behind the rear wheel center and outside in the vehicle width direction. Further, since the vehicle body side end of the vehicle body side arm is arranged on the vehicle width direction inner side with respect to the vehicle width side arm side end, such a setting can be realized relatively easily. Therefore, when a rearward force is applied to the rear wheel during braking, the rotational moment acts around the instantaneous center point outside the center of the rear wheel and the four-node link is deformed. To do. Also, when a force is applied to the rear wheel inward in the vehicle width direction during turning, a rotational moment force about the instantaneous center point of the rear wheel acts from the center of the rear wheel and the link of Section 4 is deformed. The wheels will toe in.

In this way, since the deformable and easy 4-bar linkage is formed and the instantaneous center point is set outside and behind the center of the rear wheel, the rear wheel toe-in operates extremely effectively during braking and turning,
There is an advantage that the steering stability of the vehicle is significantly improved.

Furthermore, in a side view of the vehicle body, the straight line connecting the centers of the outer pivot parts of the upper and lower two lateral arms is arranged so as to intersect the road surface behind the ground contact center of the rear wheel, so that it acts on the rear wheel when turning. The rear wheel is toe-in operated by the moment force around the straight line generated against the inward force in the vehicle width direction, and the rear wheel can be more effectively toe-in operated.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a plan view showing a schematic configuration of a main part of a rear suspension device of a vehicle, FIG. 2 is a perspective view of the same, and third is a vehicle body side of a trailing arm. FIG. 4 is a vertical cross-sectional view of a main part showing a connection state between the arm and the wheel side arm, FIG. 4 is a perspective view showing a connection state of the link,
5 is a plan view of the same, and FIG. 6 is a side view of the same. 6 ... Trailing arm, 7a ... Upper link (lateral arm), 7b ... Lower link (lateral arm), 8 ... Additional link, 9 ... Trailing link, 11 ... Rotating axis.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 60-67207 (JP, B1) JP 63-23926 (JP, B1) JP 60-42041 (JP, B2) West German patent specification 3119777 (DE, A) Car Technology [23] Separate volume Automotive Engineering Co., Ltd. 129-P. 135

Claims (3)

[Claims] 1. A trailing arm which is arranged substantially in the front-rear direction of a vehicle and which rotatably supports a rear wheel at a rear portion, and an outer end which is arranged substantially in the vehicle width direction and whose outer end portion is pivotally attached to the rear portion of the trailing arm and inner end. In a rear suspension device for a vehicle having a pair of upper and lower lateral arms pivotally attached to the vehicle body side, the trailing arm includes a vehicle body side arm whose one end is pivotally attached to the vehicle body side and the above-mentioned two trailing arms. The wheel arm is divided into a pivotal portion of the lateral arm and a rotation support portion of the rear wheel, and the axial direction is provided between the other end of the vehicle body side arm and the front portion of the wheel side arm. Is rotatably connected about a rotation axis arranged in the substantially vertical direction, and the one end of the vehicle body side arm is arranged inward in the vehicle width direction with respect to the other end. At
An extension line passing through the center of the pivot portion at both ends of the vehicle body side arm and a center line between two extension lines passing through the centers of the pivot portions at both inner and outer ends of each of the two lateral arms are provided on the rear wheel. A straight line that intersects with the rear of the center and outward in the vehicle width direction, and in a side view of the vehicle body, a straight line that connects the centers of the pivot parts of the outer ends of the two upper and lower lateral arms is behind the ground contact center of the rear wheel. A rear suspension device for a vehicle, wherein the arms are arranged so as to intersect with the rear suspension device. 2. A pivotal joint between the pair of upper and lower lateral arms and a vehicle body side arm is arranged on the front side of the vehicle body with respect to the pivotal joint between the lateral arm and the trailing arm side and along the vehicle width direction. A cross member having a central portion curved toward the rear side of the vehicle body, and one end of the vehicle body side arm and the inner ends of the pair of upper and lower lateral arms are pivotally attached to the cross member. The rear suspension device for a vehicle according to claim (1). 3. The trailing arm is pivotally attached to the outer ends of the upper and lower lateral arms via a ball joint.
A rear suspension device for a vehicle according to the item.