JPH0544162Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a rear suspension that rotatably supports the rear wheel of an automobile and alleviates vibrations and shocks transmitted from the rear wheel.

(Prior Art) There are several types of automobile suspensions, one of which is a trailing arm suspension. This trailing arm type suspension has advantages such as no change in tread or camber, a simple structure that does not take up much space, and less shock when overcoming obstacles, and is mainly used for rear suspensions. It should be noted that trailing arm type suspensions are rarely used as front suspensions because they have a large cast change and a large nose dive during braking.

In a trailing arm type rear suspension, the lateral load on the tire is supported by the trailing arm, so it is necessary to increase the lateral rigidity of the trailing arm, so it is necessary to increase the arm span and strengthen the arm. etc., making the arm itself heavier is unavoidable. If the arm weight increases, the vehicle weight will increase,
As a result, there are problems in that fuel efficiency deteriorates and manufacturing costs increase.

In order to improve this problem, for example, as disclosed in Japanese Utility Model Application Publication No. 56-62205, a lightweight swing arm placed in the longitudinal direction of the vehicle body is supported by two upper and lower lateral links. It also uses a suspension structure that increases lateral rigidity. In this suspension,
There is an advantage that the camber angle can be easily adjusted by adjusting the attachment positions of the upper and lower lateral links to each inner end. Furthermore, the vehicle body side connecting portion of the swing arm is constructed of a rubber bush.

(Problem to be solved by the invention) However, in the case of the above suspension, when the wheel moves up and down with respect to the vehicle body, that is, when bumping and rebounding, the center of the wheel is supported by both lateral links and forms an arc up and down. It draws a trajectory, moves up and down, and also moves inside the vehicle body. Therefore, the wheel side connecting portion of the swing arm itself rotates inward of the vehicle body using the vehicle body side connecting portion as a fulcrum, and the wheel similarly rotates to face toe-out.

In this way, the above-mentioned suspension using one swing arm and two lateral links has the advantage of increasing lateral rigidity, reducing weight, and facilitating camber control. However, it is not possible to control the toe change of the wheel during bumps and rebounds, and there is a concern that the wheel changes to the toe-out side during bumps and rebounds while driving, making the vehicle running unstable.

On the other hand, in a trailing arm type suspension, when the connection part of the arm on the vehicle body side is constructed with a rubber bushing, the spring constant of the rubber bushing must be reduced in order to reduce the impact transmitted to the vehicle body when the rear wheel rides on a bump on the road surface. is possible. However, as mentioned above, even if the lateral rigidity is increased with the two lateral links, since the support positions are two points, the upper and lower, the arm rotates when receiving lateral force, causing deformation of the rubber bushing. This results in undesirable toe changes, and there is a limit to reducing the spring constant of the rubber bushing.

Furthermore, even if it were possible to reduce the spring constant of the rubber bush mentioned above, the unsprung weight, together with the strut, would increase during braking, etc.
In other words, rear wheel and trailing pitching, such as brake judder, is more likely to occur.
Furthermore, the vehicle floor resonates with the vertical vibrations, causing unpleasant vibrations or muffled noise within the vehicle interior.

In other words, the object of the present invention is to improve posture controllability during bumps and rebound of the rear wheel without complicating the suspension structure, and in particular to suppress toe-out and improve toe controllability, and to improve the The objective is to prevent unpleasant vibrations such as those caused by brake judder without impairing riding comfort.

(Means for Solving the Problems) The present invention solves these problems by providing a wheel support member consisting of a single swing arm, such as a trailing arm, extending in the front-rear direction and a rear wheel support in the width direction of the vehicle body. The rear wheel support is bendable, and the rear wheel support is connected to the vehicle body by three lateral links, and the posture of the rear wheel support is controlled by these three lateral links, and the base end of the swing arm is elastically connected to the vehicle body. By setting the elastic support characteristics to be soft in the longitudinal direction of the vehicle body and hard in the vertical direction, unpleasant vibrations can be prevented without impairing riding comfort.

In other words, this means includes a rear wheel support that supports the rear wheel, a rear wheel support that is attached to the vehicle body at one point at the base end so as to be able to swing vertically, and a rear wheel support that is attached to the tip end so as to receive rotational force and longitudinal force from the rear wheel. A support member consisting of a single swing arm that supports the support and is arranged in the longitudinal direction of the vehicle body, and each outer end is located at three mutually distant points on the rear wheel support, and each inner end is located at three mutually distant points on the vehicle body. The vehicle body is rotatably attached to each of the three points via one pivoting means, and the attachment points of each outer end to the rear wheel support are not aligned in a straight line in a vertical plane in the longitudinal direction of the vehicle body. three lateral links disposed in a lateral direction, the support member being bendable in the width direction of the vehicle body with respect to a virtual axis in the length direction of the swing arm at the base end; The lateral link is attached to the rear wheel support so as to cause a toe angle displacement of the rear wheel as the rear wheel moves up and down, and the base end of the swing arm is supported against the vehicle body via an elastic bush. and its elastic support characteristics are softer in the direction in which the base end is displaced substantially longitudinally of the vehicle body, and are softer in the direction in which the base end is displaced substantially vertically than in the direction in which it is displaced substantially longitudinally in the vehicle body. This is an automobile rear suspension that is characterized by its stiffness.

(Function) In the case of the above rear suspension, the support member consisting of the rear wheel support and one swing arm is aligned in the width direction of the vehicle body with respect to the imaginary axis in the length direction of the swing arm at the base end of the swing arm. Therefore, the rear wheel support can be bent to the base end of the swing arm without being restricted in its posture or forcing the attachment point of the base end of the swing arm to the vehicle body to move unreasonably. lateral displacement is allowed. Therefore, the attitude of the rear wheel is regulated only by the three lateral links whose attachment points at their outer ends are not aligned in a straight line in a vertical plane in the longitudinal direction of the vehicle body.

In other words, by appropriately determining the length and arrangement of the three lateral links, it is possible to control the change in rear wheel attitude in a desirable manner. For example, among the three lateral links, the ones located in the upper and lower positions regulate the ground camber change by the parallel link function, and when looking at the toe change, the one in the front position of the three lateral links controls the change in ground camber. Changes in the toe-out direction can be regulated. Even if there is a toe change in the rear wheel, excessive load is prevented from being applied to the attachment parts of the swing arm to the vehicle body.

In addition, since the swing arm is one piece and is attached to the car body at a single point at the base end so that it can swing up and down, there is no increase in the number of parts, the car body attachment part is simplified, and the space it occupies is reduced. decreases. When the brake force is transmitted to the attachment point on the vehicle body via the swing arm, a brake reaction force acts in the vertical direction at this attachment point.

Based on this premise, the base end of the swing arm is supported at the above attachment point to the vehicle body via an elastic bushing, and its elastic support characteristics are maintained in the direction in which the base end is displaced approximately back and forth to the vehicle body. Since the wheels are made soft, longitudinal compliance can prevent force in the longitudinal direction from being transmitted as impact force from the rear wheels to the vehicle body. Also, when the rear wheel changes toe, the elastic bushing tries to swing around the vertical axis, but as mentioned above, this elastic bushing is soft in the front-rear direction, so it can smoothly change toe. .

On the other hand, since the above elastic support characteristics are set to be stiff in the direction in which the base end of the swing arm is displaced approximately vertically, pitching of the unsprung weight and the accompanying vibration or muffled noise of the vehicle body floor are suppressed. Ru. Particularly, as described above, since the brake reaction force acts in the vertical direction at the attachment point, the elastic support characteristics make it possible to effectively prevent brake judder.

(Effect of the invention) Therefore, according to the invention, the single swing arm is elastically supported on the vehicle body at one point at its base end, and its elastic support characteristics are maintained at one point at the base end. It is set to be soft in the direction of displacement in the longitudinal direction of the vehicle body, and hard in the direction of displacement approximately up and down, while the attachment points of the three lateral links on the vehicle body side are not lined up in a straight line in the vertical plane in the longitudinal direction of the vehicle body. In this way, the support member consisting of the rear wheel support and one swing arm can be bent in the width direction of the vehicle body with respect to the imaginary axis in the length direction of the swing arm at the base end of the swing arm. , simplifying the suspension mechanism or reducing the space it occupies, controlling the toe change and camber angle change to the desired tendency when the rear wheel bumps or rebounds, and in particular suppressing toe-out and improving toe control. It is possible to improve the durability of the elastic bushing while satisfying the basic requirements for the above, and it is also possible to prevent unpleasant vibrations such as those caused by brake judder without impairing the ride comfort of the automobile.

(Example) Hereinafter, an example of the present invention will be described based on the drawings. 1 to 3 are a plan view, a rear view, and a side view showing the overall structure of a rear suspension of an automobile. 1 is a rear wheel, which is rotatably supported by a rear wheel support 2. The rear wheel support 2 is supported by a side frame 7 and a cross member 8 of the vehicle body by one swing arm 3 and three lateral links 4, 5, and 6. Furthermore, a strut 10 is interposed between the rear wheel support 2 and the suspension tower 9.

The swing arm 3 is a thin plate that is arranged long in the front and back direction with the plate surface in the vertical direction, and the base end (front end)
It is connected to the side frame 7 at one point so as to be able to swing up and down, and supports the rear wheel support 2 at its tip (rear end). In this case, swing arm 3
The base end is elastically supported by the side frame 7 by a rubber bush 11. The shaft portion of the rubber bush 11 is supported by a bracket 12 fixed to the lower surface of the side frame 7.

On the other hand, the three lateral links are a first lateral link 4 and a second lateral link 5 arranged above and below,
and a third lateral link 6 disposed on the front side, and each lateral link is disposed long in the lateral direction of the vehicle body. The first lateral link 4 provided on the upper side has its outer end positioned above the rear portion of the rear wheel support 2 and its inner end positioned above the cross member 8, so that the first lateral link 4 can freely swing up and down via one pivoting means 14 and 17, respectively. is connected to. The second lateral link 5 provided on the lower side has its outer end positioned below the rear of the rear wheel support 2, and its inner end positioned below the cross member 8, respectively, so that the second lateral link 5 can be vertically swung via pivoting means 15 and 18. freely connected. Furthermore, the third lateral link 6 provided on the front side is shorter than both the first and second lateral links 4 and 5, has an outer end located below the front of the rear wheel support 2, and an inner end that is shorter than the cross member 8. Side frame 7 extending forward
one pivoting means 1 for each bracket 13 of
6 and 19, they are connected to each other so as to be vertically swingable.

In other words, the three lateral links 4 to 6 are placed at three points forming the vertices of a triangle spaced apart from each other on the rear wheel support 2 so that the outer ends are not aligned in a straight line in the vertical plane in the longitudinal direction of the vehicle body. At the three points whose inner ends form the vertices of a triangle separated from each other on the vehicle body,
Each is connected. In this example, each outer end pivoting means 14 to 16 of the three lateral links 4 to 6
Each of the inner end pivoting means 17 to 19 is constituted by a rubber bush.

Therefore, the rubber bush 11 that constitutes the connecting portion between the swing arm 3 and the side frame 7
has an elastic support characteristic that is soft in the direction in which the base end of the swing arm 3 is displaced approximately back and forth in the vehicle body, and is soft in the direction in which the base end is displaced approximately up and down in the vehicle body. It is set to be harder than the case. That is, in FIG. 4 showing a specific cross-sectional structure of the rubber bushing 11, 20 is an outer cylinder, 21 is an inner cylinder, and 22 is a rubber part provided between the outer cylinder 20 and the inner cylinder 21. There are cavities 2 at the front and rear positions of the inner cylinder 21, respectively.
3 and 23 are formed, and arc-shaped metal plates 24 and 24 are embedded in the upper and lower positions of the inner cylinder 21, respectively.

Therefore, the rubber bush 11 has a small spring constant in the longitudinal direction because the cavities 23, 23 are crushed and the amount of distortion increases when subjected to a load in the longitudinal direction of the vehicle body, and the spring constant in the longitudinal direction is small. Since the cross-sectional area occupied by the rubber portion 22 is reduced by the metal plates 24, 24, the amount of strain is reduced, and the spring constant in the vertical direction is large.

Next, to explain the function of the rear suspension described above, first, we will explain the effects of the rear suspension on the rear wheel 1, which occurs when braking force is applied to the rear wheel 1 while the car is running.
The longitudinal force from the rear wheel support 2 and the rotational force of the rear wheel support 2 are handled by the swing arm 3. Also,
Geometrical interference between the swing arm 3 and the lateral links 4 to 6 due to the vertical movement of the rear wheel 1 is absorbed by the deformation of the thin plate swing arm 3 and the deformation of each rubber bush. In other words, in this case, the swing arm 3 is configured to allow the rear wheel support 2 to be displaced in the lateral direction with respect to a point on the base end attached to the side frame 7, without restricting the posture of the rear wheel support 2. This causes the rear wheel 1 to deform.
The posture of is regulated by three lateral links 4 to 6.

Looking at the camber change and toe change of the rear wheel 1 when the rear wheel 1 bumps or rebounds, the camber change is caused by the first lateral link 4 and the second or third lateral links 5 and 6 arranged above and below. The lateral links 4 to 6 function as parallel links to prevent large ground camber changes, and the lengths of the lateral links 4 to 6 can be appropriately set to perform desired camber control.

On the other hand, regarding the toe change, in the case of this example,
The third lateral link 6 on the front side prevents the rear wheel 1 from changing toward the toe-out side when bumping, and also due to the influence of compliance steering, the rear wheel 1 changes toward the toe-in side when bumping.

Therefore, the rubber bush 11 at the base end of the swing arm 3 has elastic support characteristics set to be soft in the direction in which the base end of the swing arm 3 is displaced substantially longitudinally of the vehicle body, so the longitudinal compliance is large, e.g. , even if the rear wheel 1 rides on a bump on the road surface and receives force in the longitudinal direction of the vehicle body,
The rubber bush 11 is flexibly deformed to prevent large impacts from being transmitted to the vehicle body.

Further, when the rear wheel 1 changes toe, the rubber bush 11 tries to swing around the vertical axis, but since the rubber bush 11 is soft in the longitudinal direction as described above, it is difficult to make the toe change smoothly. can.

Furthermore, since the elastic support characteristic of the rubber bush 11 is set to be hard in the direction in which the base end of the swing arm 3 is displaced approximately vertically, the amplitude due to the vertical load is small, and its resonance point is It will be located on the high frequency side. Therefore, the swing arm 3 rotates using the rubber bush 11 as a relatively hard or rigid fulcrum, and the problem of unsprung weight, that is, pitching of the rear wheel 1 and the swing arm 3, is prevented. Moreover, unpleasant vibrations in the vehicle floor and muffled noise inside the vehicle are also prevented.

In particular, regarding the brake gear, since there is only one swing arm 3, when the braking force is transmitted via the swing arm 3 to the attachment point to the vehicle body, that is, to the rubber bush 11, this rubber bush 11 brakes. A reaction force will act in the vertical direction. On the other hand, as described above, the rubber bush 11 has elastic support characteristics that are soft in the direction in which the base end of the swing arm 3 is displaced approximately longitudinally of the vehicle body, but has a rigidity in the vertical direction where the brake reaction force acts. Since the height is high, the above-mentioned brake judder can be effectively prevented without impairing the ride comfort of the automobile.

In the above embodiment, the elastic support characteristics of the rubber bush 11 are set by both the cavity 23 and the metal plate 24, but the setting means may be used, such as setting only by one of them.

Furthermore, other connecting means such as ball joints may be used in addition to rubber bushings for the pivoting means 14 to 19 at both the inner and outer ends of the three lateral links 4 to 6.

Further, the swing arm may be used as a leading arm by connecting its base end to the vehicle body behind the rear wheel and reversing the front-to-back positional relationship of each lateral link.

The strut may be attached directly to the rear wheel support, or may be connected to the swing arm or any of the three lateral links.

The rear wheel can also be used as a driving wheel with a structure in which the drive shaft passes through the rear wheel support.

[Brief description of the drawings]

The drawings show embodiments of the present invention, and FIGS.
The diagram shows the rear suspension of a car.
1 is a plan view with the strut omitted, FIG. 2 is a rear view, FIG. 3 is a side view, and FIG. 4 is a sectional view of the rubber bush at the base end of the swing arm. 1... Rear wheel, 2... Rear wheel support, 3... Swing arm, 4-6... Lateral link, 7... Side frame, 8... Cross member, 11... Rubber bush, 14-19...
... Pivot means.

Claims (1)

[Claim for Utility Model Registration] A rear wheel support that supports the rear wheel, and a rear wheel support that is attached to the vehicle body at one point at the base end so as to be swingable in the vertical direction, and at the tip end so as to receive rotational force and longitudinal force from the rear wheel. A support member consisting of a single swing arm that supports a rear wheel support and is disposed in the longitudinal direction of the vehicle body; is rotatably attached to three points spaced apart from each other via one pivoting means, and the attachment points of each outer end to the rear wheel support are arranged in a positional relationship that is not aligned in a vertical plane in the longitudinal direction of the vehicle body. and three lateral links arranged in the lateral direction of the vehicle body, the support member being bendable in the lateral direction of the vehicle body with respect to a virtual axis in the longitudinal direction of the swing arm at the base end, The three lateral links are attached to the rear wheel support so as to cause a toe angle displacement of the rear wheel as the rear wheel moves up and down, and the base end of the swing arm is supported against the vehicle body via an elastic bush. and its elastic support characteristics are soft in the direction in which the base end is displaced substantially longitudinally of the vehicle body, and soft in the direction in which the base end is displaced substantially vertically in the vehicle body. An automobile rear suspension characterized by being set harder than usual.