JPH0577521B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in rear suspensions for automobiles.

(Prior Art) A system called a trailing arm type or a semi-trailing arm type has been known as an independent rear suspension for automobiles.
This rear suspension system has a trailing arm that extends in the longitudinal direction of the vehicle body and whose front end is attached to the vehicle body so that it can swing vertically.The rear end of this trailing arm has a hub support for supporting the wheel hub. The member is fixed. Further, a damper is arranged between the rear end of the trailing arm and the vehicle body above it. This type of rear suspension has a simple structure and is lightweight, but in order to sufficiently increase the lateral rigidity of the trailing arm, its cross-sectional shape must be made large and the attachment points to the vehicle body must be This requires a wide lateral spacing between the two, which increases the size of the trailing arm, which is disadvantageous in terms of weight.

A structure to solve these problems was developed in 1983.
Proposed by No. 62205. In this proposed structure, the front end of the trailing arm extending in the longitudinal direction of the vehicle body is swingably attached to the vehicle body, and the wheel hub is supported at the rear end. The outer ends of the two arranged lateral links are rotatably connected, and the inner ends of the lateral links are rotatably connected to the vehicle body. This type of rear suspension is advantageous in that the rigidity of the trailing arm does not need to be very high, but when the wheels move vertically relative to the vehicle body, the downward Also during rebound, the wheels tend to move in the toe-out direction, resulting in unstable steering such as oversteer while driving on a curved road. On the other hand, in West German Published Patent No. 2038880, a triangular upper arm disposed above and two lower arms disposed downward in parallel in front and back are used to control the wheels. A configuration is disclosed that supports.
In this structure, the posture of the wheel is basically controlled by these three arms, so by selecting the position, arrangement, and length relationship of these arms, the wheel can be adjusted relative to the vehicle body. Even when the vehicle moves in the vertical direction, it is possible to appropriately set the toe of the wheel, and compared to the structure of the prior art described above, running stability due to toe change can be improved. However, this known upper arm structure is disadvantageous in terms of both space and riding comfort, since it is composed of a triangular arm with two pivot points to the vehicle body spaced apart in the longitudinal direction. be. In other words, it is necessary to secure a large space in order to allow the triangular upper arm to swing as the wheel moves up and down. Generally, the space behind the wheels is very limited due to the need to install other suspension components such as stabilizers, so the swinging space of the triangular arm is limited to avoid interference with other parts. In order to ensure this, many constraints arise, and the degree of freedom in design is considerably restricted. While driving, an impact load is applied to the wheels in the front and rear directions due to the undulations of the road surface. This increases the height of the vehicle, making it easier for shock to be transmitted to the vehicle body and worsening ride comfort. It is possible to alleviate this impact by making the elastic bushings of the two-point joints softer, but if they are made too soft, when lateral forces act on the wheels during turns, the wheels will move in the forward direction. The camber change becomes large, resulting in a decrease in grip strength and poor steering stability.

Further, the rear end of the trailing arm of this known structure is rotatably connected to a wheel support member that rotatably supports the wheel. Therefore, in order to enable smooth vertical movement of the wheel, it is essential to make the circumferential movement of this part smooth, and in order to ensure reliability, it is actually necessary to use large seal boots etc. Separate members are required, and there is a concern that the structure will become complicated.

(Objective of the present invention) An object of the present invention is to be able to control posture changes caused by vertical movement of wheels in a favorable manner, thereby further improving running stability and reducing riding comfort. The purpose of the present invention is to provide a lightweight and compact rear suspension for automobiles.

(Structure of the Present Invention) An object of the present invention is to enable elastic deformation of a pivot portion disposed substantially in the front-rear direction of the vehicle body and formed at the front end thereof, the axis of which is disposed substantially in the width direction of the vehicle body. A rubber bush is inserted and attached to the vehicle body so that it can swing vertically, and at the rear end,
It has one swing arm means provided with a wheel support part that rotatably supports the rear wheel, and three lateral links that extend substantially in the width direction with respect to the vehicle body independently of each other, and the three lateral links Each of the lateral links is connected to the swing arm means at one end and to the vehicle body at the other end through a single pivot means whose axis is disposed approximately in the longitudinal direction of the vehicle body, while preventing rotation about the axis. , are mounted so as to be swingable in the vertical direction, and the attachment points of the three lateral links to the swing arm means are not aligned with each other in a vertical plane in the longitudinal direction of the vehicle body, and the The position of the attachment point of the first lateral link of the three lateral links to the swing arm means is located at a distance in the longitudinal direction of the vehicle body from the pivot point where the swing arm means is attached to the vehicle body. The attachment point of the second lateral link of the three lateral links to the swing arm means is located at a first position above and in front of the center of rotation of the rear wheel.
The attachment point of the third lateral link of the three lateral links to the swing arm means is located at a second position below the center of rotation of the rear wheel and rearward of the center of rotation of the rear wheel. A shock absorber configured of a spring and a damper arranged coaxially and located at a third position forward of the center of rotation is located behind the first lateral link and relative to the center of rotation of the rear wheel. This is achieved by being pivotally connected to said swing arm means in a rearward position.

According to this configuration of the present invention, the attitude of the wheel is regulated only by the three lateral links, and the arrangement of the three lateral links, that is, the vertical and longitudinal directions of each lateral link. By appropriately determining the angle of inclination, length, mounting position to the swing arm means, and lateral rigidity at the mounting position, the wheels can be easily adjusted during bumps, rebounds, and when lateral or longitudinal forces are applied to the wheels. This makes it possible to control toe changes and camber angle changes in desirable trends.

(Effects of the Invention) According to the present invention, three lateral links extending in the lateral direction of the vehicle body are provided, and the attachment points of these lateral links to the vehicle body support member are not aligned in a straight line in the vertical plane in the longitudinal direction of the vehicle body. As a result, the posture of the wheel is now restricted only by these lateral links. Therefore, by appropriately arranging the three lateral links, it is possible to cause the wheel to move in the vertical direction. , and when a lateral force or longitudinal force is applied to the wheel, it is possible to make the change in the attitude of the wheel a desirable tendency, and for example, it is possible to effectively suppress the tendency of the wheel to toe out when bumping or rebounding. become.

Furthermore, in the present invention, since the connection points of the three lateral links to the swing arm means are located at the above-mentioned positions, favorable attitude control of the rear wheel is possible. That is, each of the lateral links prevents rotation about the axis through a single pivoting means having one end connected to the swing arm means and the other end connected to the vehicle body, each of which has an axis disposed approximately in the longitudinal direction of the vehicle body. However, they are installed so that they can swing vertically, and none of them have the function of a drive shaft that transmits driving force to the rear wheels.
Since it is constructed as a pure rod member on which only axial force acts, there is greater flexibility in link arrangement compared to a structure in which the drive shaft is used as one of the links, and the drive shaft can be used as one of the links. This eliminates the problem of rotational irregularities resulting from frequent changes in the angle of the shaft of the shaft power transmission system, as in the case of a single-use arrangement. Furthermore, by arranging the three lateral links as described above, it is possible to increase the distance between the lateral links, and the axial force of the links can be reduced.

Also, among the three lateral links, the upper link regulates the wheel camber;
In order to reduce the axial force acting on this upper link, it is preferable to arrange this link as upwardly as possible. However, such an arrangement inevitably creates problems of interference with the shock absorber of the suspension. In the present invention, the first link of the three lateral links is located above and in front of the center of rotation of the wheel, and the shock absorber is located behind it, so there is no problem of interference between the link and the shock absorber. can avoid. In addition, since the shock absorber is located behind the first lateral link, the shock absorber
Compared to the case where it is placed forward of the first lateral link, it is possible to take a larger distance from the pivot point of the front end of the swing arm, and therefore the displacement of the shock absorber against bumps and rebounds can be increased. Since the displacement of the shock absorber becomes larger when the same force is generated, there is no need to reduce the damping coefficient of the damper, that is, the aperture, and the ride comfort can be improved. Furthermore, by arranging the first link at the front, the length of the first link can be shortened.

Furthermore, since the acting position of the reaction force applied from the shock absorber to the swing arm means due to the external force applied to the wheel from the road surface is located behind the rotation center of the rear wheel, the swing arm means A rotational moment is applied in a direction that displaces the elastically deformable rubber bushing at the front end of the shaft upward. As a result, the instantaneous center of the vehicle body moves upward and the vertical distance from the center of gravity of the vehicle body can be reduced, making it possible to improve pitching performance. The rotational moment applied to this swing arm means increases as the external force applied to the wheel from the road surface increases.
The amount of upward displacement of the elastically deformable rubber bushing at the front end of the swing arm means also increases, so when driving with a large external force applied to the wheels from the road surface, such as when carrying a large load, accelerating suddenly, or making sharp turns. In driving conditions where stability is important, the instantaneous center of the vehicle body can be further increased, pitching performance can be further improved, and driving stability can be improved. On the other hand, in driving conditions where riding comfort is important, such as when the loaded weight is large, when driving at a steady speed, or when driving in a straight line, the external force applied to the wheels from the road surface is small, and therefore the swing arm Since the rotational moment applied to the means is small, the amount of upward displacement of the rubber bushing at the front end of the swing arm means is small, which improves vibration absorption and makes it possible to improve riding comfort, depending on the driving condition. This makes it possible to improve ride comfort and driving stability at the same time.

In addition, the attachment point of the first lateral link, which is an upper link, to the swing arm means is located at the first position above and in front of the rotation center of the rear wheel, so if the loaded weight is large, sudden acceleration may occur. In driving conditions in which driving stability is important when a large external force is applied to the wheels from the road surface, such as when making a sharp turn, the attachment portion of the first link to the swing arm means is displaced upward to a greater extent, so the camber It becomes possible to control the characteristics and toe characteristics so as to improve running stability.

(Description of Embodiments) Referring to FIGS. 1 to 5, a wheel 10 is rotatably supported by a wheel support member 12 and connected to a vehicle body 16 via a suspension device 14. The suspension device 14 is composed of a swing arm 18, lateral links 20, 22, 24, and a shock absorber 26. The swing arm 18 has a vertically wide plate shape and extends in the longitudinal direction of the vehicle body, and one end is attached to the main frame of the vehicle body so as to be rotatable around a horizontal axis in the lateral direction of the vehicle body, and the other end is fixed to the wheel support member 12 with bolts 30. has been done. In this embodiment, the swing arm 18
and the wheel support member 12 constitute the swing arm means of the present invention, and the wheel support member 12 constitutes a wheel support portion provided at the rear end of the swing arm means. As shown in detail in FIG. 5, a rubber bushing 39 is provided at the front end of the swing arm 18 and is composed of an outer cylinder 39a, an inner cylinder 39b, and an inner cylindrical rubber 39c provided between the inner and outer cylinders. The front end of the swing arm 18 is attached to the bracket 29 of the vehicle main frame by a bolt 38 inserted into the inner cylinder 39b. The rubber bush 39 can be displaced in the axial direction as shown by the imaginary line in FIG. 5, and the axis is arranged substantially in the width direction of the vehicle body. The lateral link 20 extends substantially laterally to the vehicle body, and one end is attached to the wheel support member 12 via a rubber bushing 20a so as to be rotatable about a horizontal axis in the longitudinal direction of the vehicle body, and the other end is attached to the main frame of the vehicle body. It is attached via a rubber bushing 20b so as to be rotatable around a horizontal axis in the front-rear direction. The lateral link 22 and the lateral link 24 have rubber bushings 22a and 2 at one end, respectively.
4a to the wheel support member 12 so as to be rotatable about a horizontal axis in the longitudinal direction of the vehicle body, and the other end is attached to the rear subframe 32 on the vehicle body side via rubber bushes 22b and 24b in the same manner as in the longitudinal direction of the vehicle body. It is mounted so that it can rotate around a horizontal axis.
As shown in FIGS. 1 and 2, the shock absorber 26 includes a coil spring 34 and a damper 36 arranged coaxially, extends in the vertical direction, and has a lower end attached to the wheel support member 12 in the lateral direction of the vehicle body. It is mounted rotatably around a horizontal axis, and its upper end is mounted to the vehicle body 16 so as to be rotationally deflectable. The mounting positions of the respective lateral links 20, 22, and 24 on the wheel support member 12 are in a positional relationship that is not in a straight line within a vertical plane in the longitudinal direction of the vehicle body. Furthermore, the lateral link 20 is located below and in front of the axle 40, the lateral link 22 is located above and in front of the axle 40, and the lateral link 24 is located below and behind the axle 40. are installed at each location.
Further, as clearly shown in FIG. 3, the shock absorber 26 is attached to the wheel support member 12 at a position rearward of the axle 40, which is the center of rotation of the wheel 10.

In this example, the lateral link 22 constitutes a first link of the present invention, the lateral link 24 constitutes a second link, and the lateral link 20 constitutes a third link.

When the wheel 10 receives a force in the vertical direction, the wheel 10 is displaced in the vertical direction, and the swing arm 1
8 swings around an axis 38 for attaching the vehicle body to its front end. Therefore, the wheel support member 12
is displaced along an arcuate trajectory centered on the bolt 38 at the front end of the swing arm 18. In this case, since the wheel support member 12 is laterally supported by the three lateral links 20, 22, 24, the lateral links 20, 22, 24 also swing in the vertical direction, and their outer ends swing. Displaces laterally with movement. In the arrangement of the lateral links as in the illustrated embodiment, the lateral links 20 are laterally outwardly inclined slightly rearwardly and downwardly and have the shortest length of the three lateral links. The lateral links 22 are laterally outwardly inclined slightly rearward and upwardly, and the lateral links 24 are laterally outwardly inclined slightly downwardly.
With this arrangement, for example, if the wheel is displaced upward, the outer end of the lateral link 20 will be slightly displaced outward, but since the link 20 has a rearward inclination, the amount of outward displacement will be small. is small. The outer end of the lateral link 22 is displaced inward as the wheel is displaced upward. Also, lateral link 24
The outer end of the lateral link 20 is displaced outward, and the amount of displacement is greater than the amount of displacement of the outer end of the lateral link 20. Since the outer ends of the lateral links 20 and 22 are located forward of the outer end of the lateral link 24, a slight toe-in tendency occurs as a whole, and
The camber angle will decrease. A downward displacement or rebound of the wheel results in a slight toe-out and a slight increase in camber angle. That is, in response to vertical displacement of the wheel, a toe angle change occurs as shown by curve a in FIG. 6, and a camber angle change has a similar tendency. Curve b in FIG. 6 shows the toe angle change in the suspension of Utility Model Application No. 56-62205, and from this figure, the excellent effect of toe angle control in this embodiment can be recognized. The rubber bush 3 attaches the swing arm 18 to the main frame of the vehicle body in response to changes in the attitude of the wheels.
9 is deflected in the axial direction as shown by the imaginary line in FIG. 2 and thus causes the swing arm 18 to have the required amount of lateral excursion.

Note that when a lateral force is applied to the wheels such as when driving on a curved road, the rubber bushes 20a, 22a, 24a provided at the attachment portions between the lateral links 20, 22, 24 and the wheel support member 12 are bent. ,
By making the rigidity of these rubber bushings the same, it is possible to prevent toe changes from occurring in response to lateral forces, and by changing the rigidity of these rubber bushings as necessary, it is possible to prevent inward lateral force. It is also possible to produce a slight toe-in in response to a force and a slight toe-out in response to an outward lateral force. Furthermore, with this arrangement, almost no toe angle change occurs with respect to longitudinal force.

Note that the reaction force acting against the longitudinal force and rotational force acting on the wheel 10 is shared by the swing arm 18.

FIG. 7 shows a further different embodiment of the present invention, in which the same parts as in the previous example are given the same reference numerals. In this example, the swing arm 18
The rubber bush 39 for attaching to the bracket 29 of the front vehicle body main frame is located along its axis 39I.
is oriented laterally and tilted backwards. In this example, when the swing arm 18 bumps or rebounds from the wheel 10, the deformation of the rubber bush 39 due to the lateral displacement as shown by the imaginary line facilitates the rearward movement of the wheel support member 12.
The permissible range can be widened.

The present invention is not limited to the arrangement of the embodiments described above, but by variously changing the arrangement of the lateral link, the position and rigidity of the attachment point to the wheel support member, the camber angle and toe angle of the wheel can be changed as desired. It is possible to make it a trend.

For example, in the embodiment described above, the swing arm 18 is configured to be able to flex in the lateral direction.
The swing arm means can be mounted so as to be displaceable laterally, or the wheel support at the rear end of the swing arm means may be coupled to the front end of the swing arm means for relative displacement. It may be configured to allow lateral displacement.

[Brief explanation of the drawing]

Fig. 1 is a rear view showing the suspension of the present invention, Fig. 2 is a perspective view, Fig. 3 is a side view seen from the inside in the lateral direction of the vehicle body, Fig. 4 is a sectional view of the rubber bushing, and Fig. 5 is a A cross-sectional view showing the rubber bushing for attaching the swing arm, and Figure 6 is a diagram showing the change in toe angle when the wheel is subjected to vertical force.
FIG. 7 is a plan view of another embodiment of the invention. 10...Wheel, 12...Wheel support member, 14...
... Suspension device, 18 ... Swing arm, 20 ... Lateral link, 22 ... Lateral link, 24 ... Lateral link, 26 ... Shock absorber.

Claims (1)

[Scope of Claims] 1. An elastically deformable rubber bushing whose axis is disposed approximately in the width direction of the vehicle body is interposed in a pivot portion formed at the front end of the pivot joint portion, which is disposed approximately in the longitudinal direction of the vehicle body. , one swing arm means which is attached to the vehicle body so as to be swingable in the vertical direction, and which is provided with a wheel support portion at its rear end that rotatably supports the rear wheel; and three lateral links extending in the width direction, each of the three lateral links having one end connected to the swing arm means and the other end connected to the vehicle body, each with an axis extending approximately in the longitudinal direction of the vehicle body. The attachment points of the three lateral links to the swing arm means are attached to each other so as to be able to swing vertically while preventing rotation around the axis through one pivoting means. The third lateral link of the three lateral links has a positional relationship that is not aligned in a straight line in a vertical plane in the longitudinal direction of the vehicle body, and is located away from the pivoting portion of the swing arm means to the vehicle body in the longitudinal direction of the vehicle body. The position of the attachment point of the first lateral link to the swing arm means is at a first position above and in front of the rotation center of the rear wheel, and the attachment point of the second lateral link of the three lateral links The attachment point to the swing arm means is located at a second position below the first position and rearward from the center of rotation of the rear wheel, and the third lateral link of the three lateral links swings. The attachment point to the arm means is located at a third position forward of the center of rotation of the rear wheel, and the shock absorber constituted by a spring and a damper arranged coaxially is connected to the first lateral link. A rear suspension for an automobile, characterized in that the rear suspension is pivotally connected to the swing arm means at the rear of the rear wheel and at a position rearward of the center of rotation of the rear wheel. 2. The rear suspension for an automobile according to claim 1, wherein the other end of the second lateral link is connected to a subframe extending in the width direction of the vehicle body. 3 Of the three lateral links, the second
3. The rear suspension for an automobile according to claim 1, wherein the lateral link is the longest. 4. Claims 1 to 3, characterized in that the attachment point of the second lateral link to the swing arm means is located below and behind the center of rotation of the rear wheel. The rear suspension of the automobile according to any one of the above.