JPS6249202B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a rear suspension that rotatably supports a rear wheel of an automobile and also alleviates vibrations and shocks transmitted from the rear wheel.

(Prior Art) There are several types of rear suspensions for automobiles, one of which is a trailing arm type rear suspension.

In a trailing arm type rear suspension, the lateral load on the tires 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 cannot be avoided. 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 such problems, for example,
As disclosed in No. 56-62205, there is a suspension structure in which a lightweight swing arm placed in the longitudinal direction of the vehicle body is supported by two lateral links, making it lightweight and increasing lateral rigidity. Proposed. A suspension having this structure is shown in FIGS. 1 to 3. FIG. 1 is a perspective view seen diagonally from the rear, and shows a swing arm 1 whose front end 1a is rotatably attached to the vehicle body (not shown).
At the other end 1b are outer ends 3a, 4a of two lateral links 3, 4 located above and below the vehicle body and extending in the width direction.
is rotatably attached, and the inner ends 3b, 4b of the upper and lower lateral links 3, 4 are rotatably attached to the vehicle body. The other end 1b of the swing arm 1 rotatably supports the rear wheel 2 and also serves as a wheel support.
The other end 1b of the swing arm 1 is connected to the vehicle body via a shock absorber (not shown) and a spring (not shown), thereby alleviating vibration and shock from the wheel 2. 1b is designed to be able to move up and down relative to the vehicle body. FIG. 2 is a plan view of this suspension viewed from above the vehicle body, with the upper side of the figure being the front of the vehicle body. FIG. 3 is a front view of this suspension viewed from the rear of the vehicle body, in which the up and down direction in the figure is the up and down direction of the vehicle body, and the left and right direction is the width direction of the vehicle body.

The suspension constructed in this manner has the advantage that the camber angle can be easily adjusted by adjusting the attachment positions of the inner ends 3b, 4b of the upper lateral link 3 and lower lateral link 4 to the vehicle body. However, when the wheel 2 moves up and down with respect to the vehicle body, that is, during bumps and rebounds, the center O of the wheel 2 is supported by the upper and lower lateral links 3 and 4, and is approximately an arc as shown by the broken lines of arrows A and B. Draw the trajectory above. Therefore, the wheel center O moves up and down with respect to the car body, and inside the car body (in the car width direction, in the direction where the lateral link is provided to the wheel, that is, the left side for the right wheel, and the right side for the left wheel). ), that is, move in the direction of arrow C. When the wheel center O moves inward to the vehicle body, the other end 1b of the swing arm 1 on which the wheel 2 is supported also moves inward to the vehicle body,
For this reason, the swing arm 1 is rotated counterclockwise in FIG. 2 with one end 1a as the center. Therefore, the wheel 2 supported by the other end 1b of this swing arm 1 also moves counterclockwise (in the direction of arrow D).
will be passed on to In other words, face the direction of 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, there is a problem in that it is not possible to control the toe change of the tire during bumps and rebounds, and the wheel changes to the toe-out side during bumps and rebounds while driving, making the running of the vehicle unstable.

On the other hand, in West German Published Patent Application No. 2038880, the wheels are supported by a triangular upper arm disposed above and two lower arms arranged in parallel at the front and back disposed below. A configuration configured to do this is disclosed. In this case, the position of the wheel is basically regulated by these three arms, so the position of these arms,
By selecting the arrangement and length relationship, it is possible to appropriately set the toe of the wheel even when the wheel moves in the vertical direction relative to the vehicle body, which is more effective than the conventional structure described above. This makes it possible to improve running stability due to toe changes. However, since the upper arm of this publication is composed of a triangular arm with two pivot points to the vehicle body separated in the longitudinal direction,
This is particularly disadvantageous in terms of both space and riding comfort.
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. In general, the space behind the wheels is extremely limited due to the necessity of arranging other suspension components such as stabilizers, so in order to ensure the swinging space of the triangular arm so as not to interfere with other components, Many constraints arise, and the degree of design freedom is considerably restricted. Furthermore, while driving, impact loads are applied to the wheels in the front and rear directions due to the unevenness of the road surface. As a result, the shock is easily transmitted to the vehicle body, worsening the ride comfort. It is possible to alleviate this impact by making the elastic bushing of the two-point pivot joint softer, but if it is made too soft, the camber change ( (in the forward direction) becomes large, resulting in a decrease in grip force and worsening of steering stability.

Further, the rear end of the trailing arm of this publication is connected to a wheel support member that rotatably supports a wheel so as to be rotatable. 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 parts such as large seal boots. Separately required,
There is a concern that the structure will become more complicated.

Also, generally in independent suspensions,
Setting the camber to be negative when bumping is effective in increasing the running stability of the vehicle. To do this, the inner end 3b of the side lateral link 3 may be lowered as shown by arrow A, as shown in FIG. Note that lowering the inner end 3b is also desirable from the viewpoint of widening the interior of the vehicle body, improving comfort, and expanding the trunk space. However, if the inner end 3b is lowered too much, there is a problem in that too much negative camber is created when bumping, leading to uneven tire wear. Furthermore, if the inner end 3b is lowered downward, it will approach the inner end 4b of the lower lateral link 4, and the pitch that receives the lateral force acting on the tire will become smaller, increasing the load on each link, reducing reliability and increasing noise. A problem arises.

(Object of the Invention) In view of the above-mentioned problems, the present invention is lightweight, has high lateral rigidity, can control both camber change and toe change without impairing ride comfort, and can control camber change during bumps and rebound. The purpose of this invention is to provide a rear suspension that can properly perform the following.

(Structure of the Invention) In the rear suspension of the present invention, a rear wheel is rotatably supported by a wheel support, a swing arm is positioned in the longitudinal direction of the vehicle body, the tip of the swing arm is used as a wheel support, and the base end of the swing arm is is attached to the vehicle body, and the tip is made to be able to swing freely in the vertical direction of the vehicle body centering on the base end, and to receive rotational force and longitudinal force from the rima wheel. In a rear suspension for an automobile, three lateral links are arranged in the width direction of the vehicle body, each having an outer end that is movably connected and an inner end that is rotatably connected to three mutually spaced points on the vehicle body. The outer end connection points of these three lateral links are such that the outer end connection points of two of these lateral links are located in the longitudinal direction of the vehicle body, and the outer end connection points of the remaining lateral links are located at the two above-mentioned points. The inner end connection points of the remaining lateral links located above this lateral link are located below and forward of the outer end of the vehicle body than the outer end connection points of the lateral links. It is characterized by being located at.

Furthermore, in the rear suspension of an automobile according to the present invention, two straight lines passing through the outer end connecting point of the remaining lateral link and the outer end connecting point of the two lateral links, respectively, are arranged in the longitudinal direction of the vehicle body. It is characterized by three lateral links arranged so that the projected point of the rear wheel's grounding point is located between these two straight lines when projected onto an extended vertical projection plane. .

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

4 to 6 show preferred embodiments of the rear suspension of the present invention, with FIG. 4 being a perspective view as seen diagonally from behind, FIG. 5 being a plan view as seen from above the vehicle body, and FIG. 6 being a perspective view of the vehicle body. These are side views seen from the rear, and as shown in these figures, the rear wheel 12 is rotatably supported by a wheel support 16.
This wheel support 16 has a swing arm 1
The distal end 11b of the swing arm 1 is fixed, and the base end 11a is attached to the vehicle body so that the swing arm 11 is positioned in the longitudinal direction of the vehicle body. Furthermore, the proximal end 1
The attachment portion 1a is such that the swing arm 11 can swing in the vertical direction of the vehicle body centering on the base end 11a. For this reason, wheel support 16
The rear wheel 12 can move in the vertical direction of the vehicle body, and the coil spring 17a and damper unit 17 have their lower end attached to the wheel support 16 and their upper end attached to the vehicle body.
(b) appropriately restricts the vertical movement of the vehicle body, and also dampens vibrations and shocks transmitted from the wheels. The wheel support 16 has three first, second and third wheels arranged in the lateral direction of the vehicle body.
Outer ends 13a of lateral links 13, 14, 15,
14a, 15a are attached by rubber bushings, ball joints, etc., and the inner ends 13b, 14b,
15b is attached to the vehicle body. At this time, the inner end 14 of the second lateral link 14 located above
The second lateral link 14 is arranged such that the second lateral link b is located a distance "l" in front of the vehicle body and a distance "d" below the vehicle body with respect to the outer end 14a. By doing so, the interior of the vehicle body can be pushed downward to expand the interior space of the vehicle to improve comfort and to make the trunk room larger. Furthermore, since the inner ends 14b are not only moved downward but also moved forward, the inner ends 14b, 1 of the second and third lateral links 14, 15 are mainly subjected to lateral forces.
The mutual pitch of the links 5b does not become small, and the load on each link can be prevented from increasing.

Note that the joints between both ends of the swing arm 11 of the rear suspension configured as described above and both ends of the first, second, and third lateral links 13, 14, and 15 are formed using a ball joint or the like that does not allow dimensional changes. In the case of a solid connection, all six degrees of freedom are geometrically constrained, making it impossible for the rear wheel 12 and wheel support 16 to move.
For this reason, at least one part of each joint, swing arm, or lateral link itself is made flexible, absorbing the amount of geometrical interference that occurs when the wheel moves up and down, and allowing rear wheel movement. I have to.

Next, with the rear suspension configured as above,
The control of toe change when the vehicle bumps and rebounds will be explained. The rear wheel 12 moves upward relative to the vehicle body when bumping, and moves downward when rebounding. For this reason, the first, second and third lateral links 13,
Each outer end 13a, 14a, 15a of 14, 15 is,
Each inner end 13b, 14 has a radius of each link.
It moves along an arc-shaped locus shown by broken lines E, F, and G in the figure, centered on points b and 15b. Therefore, each outer end 13a, 14a, 15a is connected to a circular arc-shaped broken line E,
It moves up and down along F and G and also moves inside the vehicle body. At this time, since the length of each link is different,
The amount of movement inward of the vehicle body is also different; the amount of movement of the outer end 13a of the first lateral link 13 having the shortest link length is the largest, and the amount of movement of the outer end 15a of the third lateral link 15, which is the longest, is the smallest. The first lateral link 13 is the second and third lateral links 14 and 15.
Since the front end of the rear wheel 12 is disposed further forward in the vehicle body, the front end of the rear wheel 12 is pulled inward, that is, moved toward the toe-in side. In this case, since the outer ends 13a, 14a, and 15a of each link move inward to the vehicle body, the wheel center also moves inward, and the first
The swing arm 11 is rotated around the base end 11a and the wheel changes to the toe-out side in the same way as shown in the examples shown in FIGS. This can be offset. That is, by appropriately setting the length of each link, it is possible to control toe changes during bumps and rebounds.

Next, camber changes during bumps and rebounds will be explained. To create a negative camber when bumping, the second step is shown in Figure 6.
All that is required is to move the inner end 14b of the lateral link 14 downward. However, simply lowering the inner end 14b tends to create too much negative camber when the bump is large, and conversely tends to increase the positive camber upon rebound. Therefore, in this embodiment, the inner end 14b is moved toward the front of the vehicle relative to the outer end 14a. In this way, at the time of a bump, the wheel support 16 moves along an arc-shaped trajectory centering on the base end 11a of the swing arm, and therefore moves upward and forward with respect to the vehicle body. At this time, as the wheel support 16 moves upward, the outer end 14a of the second lateral link 14 also moves upward along the trajectory F shown in FIG. 6 and is pulled inward to the vehicle body, giving a negative camber to the tire. . At the same time, as the wheel support moves forward of the vehicle body, the inner end 1 of the second lateral link 14
4a is moved toward the front of the vehicle. Therefore, as can be seen from FIG. 5, when the inner end 14a moves forward, the second
The inner end 14a is pushed outward by the lateral link 14, giving a positive camber to the tire. In this way, the negative camber generated by the above-mentioned upward movement of the wheel support and the positive camber generated by the forward movement of the wheel support are combined to make the amount of negative camber at the time of a bump appropriate.

FIG. 7 is a graph showing camber changes during bumps and rebounds, with the positive side of the horizontal axis representing the bump amount, the negative side representing the rebound amount, and the vertical axis representing the camber. In this graph, the solid line V indicates the ideal curve of camber change required from the viewpoint of running performance and stability, and the dashed line V indicates the second curve.
The camber change is shown when the inner end 14b of the lateral link 14 is simply moved downward relative to the outer end 14a, and the broken line V indicates the camber change when the inner end 14b of the second lateral link 14 is moved downward relative to the outer end 14a. This shows the camber change in the case of the rear suspension of this embodiment in which the rear suspension is moved forward as well as moved forward. As can be seen from this graph, if only the inner end 14b of the second lateral link is moved downward, the negative camber at the time of a bump becomes too large, which may lead to uneven wear of the tire, and the negative camber at the time of rebound becomes too large. There is a risk that the camber will become too large, making driving unstable. On the other hand, in the case of the rear suspension of the present invention, a camber change V close to the ideal curve V can be obtained.

FIG. 8 is a side view of a preferred embodiment of the rear suspension of the present invention, viewed from the side of the vehicle body. In the figure, the left side indicated by the arrow indicates the front of the vehicle body, and passes through the center of each of the outer ends 13a and 14a in this figure among the outer ends 13a, 14a, and 15a of the three lateral links connected to the wheel support 16. straight line S
1, and a straight line S passing through the centers of the outer ends 14a and 15a.
Consider 2. If the intersections of the straight lines S1 and S2 with the road surface are Y and Z, respectively, when driving, the wheel 1
The input point of the lateral force acting on the vehicle 2 (this point is located slightly behind the ground contact point when the vehicle is running) is located between the intersection points Y and Z mentioned above. In this way, when a lateral force acts on the wheel 12, the second lateral link 14 located above receives the pulling force, and the first and third lateral links located below
The lateral links 13 and 15 will receive compressive force, and two links will receive the compressive force that reduces the allowable load due to buckling, etc., and one link will receive the tensile force that has a large allowable load. Load sharing among links becomes optimal.

In the embodiments described above, the coil spring and damper unit are attached to the wheel support, but they can be attached to any of the lateral links or the swing arm instead. Furthermore, in the case of a rear-wheel drive vehicle, it is also possible to have the drive shaft pass through the wheel support. It is also possible to reverse the front and rear of the suspension to make it a leading arm type instead of a training arm type.

(Effects of the Invention) As explained above in detail, by using the rear suspension of the present invention, the lateral rigidity of the suspension can be increased and the weight can be reduced, and both toe control and camber control can be achieved. can. Further, by optimizing camber changes during bumps and rebounds, uneven tire wear can be suppressed and the running stability of the vehicle can be improved.

[Brief explanation of the drawing]

1 to 3 are views showing an example of a conventional rear suspension, in which FIG. 1 is a perspective view, FIG. 2 is a plan view, and FIG. 3 is a front view. 4 to 6 show one embodiment of the rear suspension of the present invention, in which FIG. 4 is a perspective view, FIG. 5 is a plan view, and FIG. 6 is a front view. FIG. 7 is a graph showing camber changes during bumps and rebounds, and FIG. 8 is a side view showing one embodiment of the rear suspension of the present invention. 1, 11... Swing arm, 2, 12... Rear wheel, 13... First lateral link, 14
...Second lateral link, 15...Third lateral link, 16...Wheel support, 17a...
Coil spring, 17b... damper unit.

Claims (1)

[Scope of Claims] 1. A wheel support that rotatably supports a rear wheel; a base end attached to the vehicle body and a distal end attached to the wheel support, disposed in the longitudinal direction of the vehicle body, and with the distal end centered around the base end; A swing arm that can freely swing in the vertical direction of the vehicle body and receives rotational force and longitudinal force from the rear wheel; The wheel support is comprised of three lateral links arranged in the lateral direction of the vehicle body and rotatably attached to three separate points via one pivoting means, respectively, and the wheel support is allowed to be displaced laterally with respect to the vehicle body. It is connected to the vehicle body via the swing arm, and the outer end connection point of one of the three lateral links is connected to the outside of the other two lateral links located at the front and rear of the vehicle body. It is placed above the end side connection point, and the inner end side connection point of this upper lateral link is
A rear suspension for an automobile, characterized in that the rear suspension is disposed below and in front of the vehicle body from the connection point on the outer end side of the link. 2. In a vertical projection plane extending in the longitudinal direction of the vehicle, between two straight lines passing through the outer end connecting point of the upper lateral link and the outer end connecting points of the other two lateral links. 2. A rear suspension for an automobile according to claim 1, wherein said three lateral links are arranged such that a point of input of lateral force to the rear wheel is located at .