JPH07106683B2 - Car rear suspension - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear suspension of an automobile, and particularly to a rear suspension of a trailing arm type such as a semi-trailing arm type or a full trailing arm type during bumping and rebounding. Concerning the camber control measures of.

(Prior Art) Conventionally, as such a trailing arm type rear suspension, as shown in JP-A-58-12811, a wheel is rotatably supported and a base end has at least two.
A semi-trailing arm that is attached to the vehicle body in an up-down direction via elastic bushes at one point, one end is rearward of the wheel support part of the semi-trailing arm, and the other end is rotatable on the vehicle body. It is known that an assist link connected to the wheel is provided and the wheel is toe-in changed when a lateral force is applied to the wheel.

(Problems to be Solved by the Invention) By the way, it is generally known that it is preferable to control the camber change of the wheels in accordance with the running state of the automobile. For example, when turning, the car body rolls due to centrifugal force, and therefore, when bumping, the wheel of the turning outer wheel has an appropriate negative camber with a ground camber angle of zero relative to the car body (the upper end of the wheel when viewed from the front of the car body is It is preferable that the vehicle is tilted inward of the vehicle body) because the steering stability during turning can be improved. Further, it is preferable to suppress the change in the camber of the wheel to be small at the time of bumping and rebounding on a bad road during straight running because the canvas last can be prevented and the straight running performance can be improved.

However, in the conventional full trailing arm type rear suspension, the camber change does not occur in the wheel during bumping and rebounding. Also, in the case of the semi-trailing arm type, the camber and toe angle change of the wheel at the time of bumping and rebound are uniquely determined by the inclination of the semi-trailing axis, and it is compatible with the toe angle change. Under the present circumstances, it is impossible to properly control the camber according to the driving condition.

On the other hand, U.S. Pat. No. 3,333,654 and the drawings disclose a trailing suspension having a link for correcting a camber change. However, in this conventional technology, since the drive shaft is configured to restrict the lateral displacement of the wheels, the tilt axis of the swing shaft of the arm is largely tilted toward the front-rear direction of the vehicle body. As a result, the tread change due to the vertical movement of the wheel becomes too large, which causes the straight running stability to deteriorate and the tire to wear. Furthermore, in order to regulate the lateral force that enters the wheel, it is necessary to make the structure of the joint part of the drive shaft complicated, which increases the cost and makes it difficult to use the commonly used constant velocity joint. Is.

In view of the above, an object of the present invention is to appropriately control a camber change according to a bump and a rebound by a simple structure of providing a camber control mechanism including a link mechanism in the trailing arm type rear suspension as described above. It is possible to enable the camber control adapted to the running condition.

(Means for Solving the Problems) In order to achieve the above-mentioned object, a technical solution of the present invention is that a rear wheel is rotatably supported, and a base end of the rear wheel is swingable in a vertical direction on a vehicle body through an elastic bush. In a trailing arm type rear suspension equipped with a trailing arm attached to a vehicle, a base end is fixed near a rear wheel support portion of the trailing arm, and a tip is extended downward inward of a vehicle body. At the tip of the first control link, there is provided a link mechanism including the second control link, the other end of which is rotatably connected to the vehicle body, and the second control link has a vehicle body side rotation center point. The trailing arm is installed below the body of the trailing arm with a set amount offset.

(Operation) As a result, at the time of bumping and rebounding, the vehicle body side rotation center point of the second control link with respect to the swing center axis line of the trailing arm is offset downward from the vehicle body, whereby the first control link and the second control link. There is a difference between the rotation locus of the trailing arm about the swing center axis of the trailing arm and the rotation locus of the second control link around the vehicle body side rotation center point. The camber control amount (correction amount) of the rear wheel at the time of bumping and rebounding becomes the camber of the rear wheel according to bumping and rebounding under the elastic deformation of the elastic bushing that constitutes the swing center point of the trailing arm. It becomes possible to control change appropriately.

(Effects of the Invention) Therefore, according to the present invention, a simple structure in which the camber control link mechanism including the first and second control links is added to the existing trailing arm type rear suspension is used to respond to bumps and rebounds. Since the change in the camber of the wheels can be controlled appropriately, a negative camber (relative to the vehicle body) that makes the ground camber angle to zero when turning is possible, which can improve the steering stability and also when driving straight ahead. The change in camber can be suppressed to a small level and the running stability thereof can be improved, which can greatly contribute to the improvement of the steering stability and the running stability of the automobile and the easy implementation thereof.

In addition, in the semi-trailing arm type where the camber change is uniquely determined, the camber change can be controlled, which reduces the restrictions on the placement of the semi-trailing arm and increases the design flexibility of the rear suspension. It also has the advantage.

As a method of obtaining an appropriate negative camber, the swing axis of the trailing arm is determined by lateral rigidity, toe angle, or layout requirements. Therefore, when an excessive negative camber is generated, the camber control link mechanism should be used. Correct the camber direction to obtain an appropriate negative camber. Conversely, if the negative camber determined by the tilt of the swing axis is small, correct the negative camber direction by using the camber control link mechanism to obtain an appropriate negative camber. It goes without saying that you should get it.

(Example) Hereinafter, an example as a specific example of the technical means of the present invention will be described with reference to the drawings.

1 to 3 show a first embodiment in which the present invention is applied to a semi-trailing arm type rear suspension having two vehicle body side mounting points. In the figure, the rear suspension structure for the right rear wheel W is shown.

In the schematic view shown in FIG. 1, reference numeral 1 is a semi-trailing arm arranged substantially in the front-rear direction of the vehicle body. The semi-trailing arm 1 is formed by connecting a bifurcated front member 11 and a substantially cylindrical rear member 12 to the front and rear. The rear member 12
Is a cylindrical rear wheel supporting portion 121 that rotatably supports the rear wheel W, a connecting portion 122 that projects forward from the rear wheel supporting portion 121 and is connected to the forked base portion 111 of the front side member 11, and the connecting portion. The first portion, which will be described later, protrudes inward from the portion 122.
It has a control link fixing portion 123 to which the base end portion of the control link 21 is fixed. On the other hand, the front member 11
Is connected and fixed to the connecting portion 122 of the rear member 12 by the bolt 13 at the fork base portion 111 as described above, and the fork fork portions 112, 112 branched from the fork base portion 111 respectively extend inward and forward, The tips of the bifurcated branches 112, 112 (that is, the base end of the semi-trailing arm 1) are elastic bushes 1.
It is attached to the vehicle body via 4, 14 so that it can swing vertically.

2 is a camber control link mechanism including a first control link 21 and a second control link 22. The base end of the first control link 21 is fixed to the control link fixing portion 123 of the semi-trailing arm 1 (that is, in the vicinity of the rear wheel supporting portion 121) by a bolt 23, and the tip end thereof is directed inward and downward. It is extended. On the other hand, the second control link 22 is arranged in the vertical direction, and one end (lower end) of the second control link 22 is attached to the tip end of the first control link 21 by a ball joint.
It is rotatably connected via 24, and the other end (upper end) is rotatably connected via a ball joint 25 of the vehicle body. The length of the second control link 22 is set shorter than that of the first control link 21.

Further, in the second control link 22, the vehicle body side rotation center point P (ball joint 25) is the swing center axis line 1 of the semi-trailing arm 1 (both elastic bushes 14, 1).
It is installed at the bottom of the vehicle with a set amount e offset to the line connecting 4).

2 and 3 more specifically show the semi-trailing arm type rear suspension shown in FIG. 1, and in FIGS. 2 and 3 the second control link 22 of the second control link 22 is shown. The vehicle body side rotation center point P is offset to the vehicle body lower side with respect to the swing center axis line 1 of the semi-trailing arm 1 and also to the vehicle body front side. Further, 3 is a shock absorber arranged vertically, and the lower end of the shock absorber 3 is at the rear end of the semi-trailing arm 1, that is, the rear wheel support part.
It is connected to a shock absorber mounting portion 124 that projects rearward from 121, and the upper end is connected to the vehicle body. Further, 4 is a coil spring arranged on the outer periphery of the shock absorber 3, 5
Is the rear axle shaft.

Next, to explain the function and effect of the first embodiment,
When bumping or rebanding the rear wheel W, the rear wheel W is attached to the semi-trailing arm 1 with respect to the vehicle body.
A camber composed of a first control link 21 that swings in the vertical direction via a base end and is fixed at the base end in the vicinity of the rear wheel support portion 121 of the semi-trailing arm 1 and a second control link 22 connected to the tip thereof. It swings via the control link mechanism 2.

In this case, the vehicle body side rotation center point P (ball joint 25) of the camber control link mechanism 2 (second control link 22) is installed below the vehicle body with respect to the swing center axis line l of the semi-trailing arm 1. As shown in FIG. 1, because of the offset, the connecting point Q between the first control link 21 and the second control link 22
The (ball joint 24) rotates about the rotation locus q ₁ about the swing center axis l of the semi-trailing arm ₁ and the vehicle body side rotation center point P of the second control link 22. A difference occurs between the rotation locus q ₂ . As shown in FIG. 1, the difference in the loci is caused by the second control link 22.
When the vehicle body side rotation center point P is offset right below the vehicle body with respect to the swing center axis line 1 of the semi-trailing arm 1, both the first and second control links 21 at the time of bumping and rebounding. , 22 is a correction amount in the positive direction of the camber control with respect to the camber change of the rear wheel W which occurs when only the semi-trailing arm 1 is swung.

The direction of the camber control correction amount by the camber control link mechanism 2 is the camber correction in the positive direction at the time of bumping and rebounding in FIG. Is offset to the front with respect to the swing center axis line l of the semi-trailing arm 1 as shown in FIGS. 2 and 3, is located directly below as shown in FIG. 1, or is offset to the rear. The direction of the correction amount varies depending on whether the correction is performed, and the correction amount in either the positive or negative direction can be obtained. This will be explained with reference to the concrete example shown in FIG.
FIG. 7A shows a case where the vehicle body side rotation center point P of the second control link 22 is located forward of the swing center axis line 1 of the semi-trailing arm 1. A connecting point Q with the control link 22 is shown by a turning locus q ₁ that turns about the swing center axis line ₁ and a turning locus q ₂ that turns about the vehicle body turning center point P. A difference occurs and the camber correction amount in the positive direction is obtained during bumping, while the camber correction amount in the negative direction is obtained during rebounding (note that the rebound amount is reversed to the positive correction amount in the positive direction). Further, FIG. 7 (b) shows a case where the vehicle body side rotation center point P is located right below the swing center axis line l, and as described above, the camber correction in the positive direction is performed at the time of bumping and rebounding. It becomes the amount. Further, in FIG. 7 (c), the vehicle body side rotation center point P is the swing center axis line l.
In the case where the bumps are located rearward with respect to Q, there is a difference as shown in the rotation loci q ₁ and q ₂ about ₁ and P of Q, and the bumps are reversed, contrary to FIG. Sometimes, the camber correction amount is in the negative direction (note that when the bump becomes too large, it is inverted to the correction amount in the positive direction), while at the time of rebound, the correction amount is in the positive direction.

Then, the actually generated camber control amount in consideration of the correction amount as described above is obtained under the elastic deformation of the vehicle body side elastic attachment points (elastic bushes 14 and 14) of the bump and the rebound semi-trailing arm 1. Therefore, against excessive changes in the negative camber direction determined by the swing axis of the semi-trailing arm 1 during bumping during turning, the camber control link mechanism 2 laid out as shown in FIG. 7 (a) is used. By correcting the positive camber direction, the rear wheel W can be made to be an appropriate negative camber (relative to the vehicle body) that makes the ground camber angle zero, and an excessive change in the positive camber that occurs during rebound can be prevented.
By correcting the negative camber direction by the camber control link mechanism 2 laid out as shown in FIG. (A), the rear wheel W can be made an appropriate positive camber (relative to the vehicle body) that makes the ground camber angle zero. Therefore, steering stability during turning can be improved. In addition, it is possible to suppress the camber change of the rear wheel W to be small when traveling straight ahead, bumping or rebounding on a bad road,
It is possible to improve straight running performance.

Further, the bump amount due to a bad road during straight running is large and the bump amount during turning is not so large. Therefore, when the camber control link mechanism 2 laid out as shown in FIG. 7C is used, the bump amount is small. The camber correction in the negative direction can be performed in the region, and the camber correction in the positive direction can be performed in the region where the bump amount is large, so that both the straight traveling bad road traveling and the turning traveling can be achieved. And
It is preferable that the camber change is small to prevent the canvas last on a bad straight road, and it is preferable to use a negative camber at the bump to make the ground camber angle to zero at the time of turning. If the layout is set as shown in Fig. 7 (c) above so that a negative camber will be obtained when the vehicle is turning and the bump amount is not so large,
The above compatibility can be achieved.

Further, since the camber change can be controlled according to the bump and the reband as described above, the position of the semi-trailing arm 1, the direction of the swing center axis line 1 and the like can be freely selected so as not to interfere with the vehicle body. The degree of freedom in designing the suspension can be increased.

Further, the base end of the first control link 21 in the camber control link mechanism 2 is near the rear wheel support portion 121 of the semi-trailing arm 1 (fixed portion 123).
Since the camber control link mechanism 2 shortens the length of the portion where the semi-trailing arm 1 is twisted, the camber control link mechanism 2 is advantageous in improving the torsional rigidity and reducing the weight accordingly.

Further, the second control link 22 is arranged in the vertical direction, and the length thereof is set shorter than the length of the first control link 21, so that the mounting point of the camber control link mechanism 2 on the vehicle body side can be set. It can be made high, which is advantageous in the layout of the rear suspension.

FIGS. 4 to 6 show a second embodiment of the present invention applied to a semi-trailing arm type rear suspension having one mounting point on the vehicle body side (note that the same parts as those of the first embodiment are the same). Will be assigned and the description thereof will be omitted).
In this case, since the semi-trailing arm 1'has only one mounting point on the vehicle body side, the lateral link 6 is required to secure lateral rigidity against lateral force acting on the rear wheel W.

That is, in this example, the semi-trailing arm 1'comprises a front member 11 'and a rear member 12'. The rear member 12 'has a rear wheel supporting portion 121', a connecting portion 122 'and a control link fixing portion 123', and a lateral link mounting for mounting the lateral link 6 in the vicinity of the control link fixing portion 123 '. Part 12
Have 5 '. On the other hand, the front member 11 'is connected and fixed at its rear end to the connecting portion 122' of the rear member 12 ', and its front end portion extends forward and swings vertically with respect to the vehicle body via the elastic bush 14'. It is installed freely.

A lateral link 6 is provided between the semi-trailing arm 1'and the vehicle body B. One end of the lateral link 6 is rotatably connected to the vehicle body B via a ball joint 61 at a position inward of the vehicle body mounting point (elastic bush 14 ') of the semi-trailing arm 1', and The end is rotatably connected to the lateral link mounting portion 125 'of the semi-trailing arm 1'via a ball joint 62 to ensure lateral rigidity against a lateral force acting on the rear wheel W. . The lateral link 6 and the semi-trailing arm 1'having one mounting point on the vehicle body side perform the same function as the semi-trailing arm 1 having two mounting points on the vehicle body side of the first embodiment. I am configuring.

Further, between the semi-trailing arm 1 ′ and the lateral link 6, the control link fixing portion 123 ′ (rear wheel support) of the same structure as the first embodiment, that is, the base end of the semi-trailing arm 1 ′ is provided. A first control link 21 fixed near the portion 121 '), a lower end rotatably connected to the first control link 21, and an upper end rotatably connected to the vehicle body B through ball joints 24 and 25, respectively. A camber control link mechanism 2 including a link 22 is arranged. The vehicle body side rotation center point P of the second control link 22 connects the vehicle body side attachment points (the elastic bush 14 'and the ball joint 61) of the semi-trailing arm 1'and the lateral link 6 to the vehicle body front-rear direction. It is installed below the vehicle body by a set amount e with respect to a straight line 1'that is inclined with respect to the center line (that is, the swing center axis of the semi-trailing arm 1 '). The rest of the configuration is the same as in the first embodiment.

Therefore, in the case of this example, the semi-trailing arm 1 having the two vehicle body side attachment points in the first embodiment is
By using the semi-trailing arm 1'having one mounting point on the vehicle body and the lateral links 6 each end of which is rotatably connected to the vehicle body B and the semi-trailing arm 1 ', bumps and rebounds can be achieved. The corresponding camber control is performed under the elastic deformation of one elastic bush 14 ', which facilitates the camber control and is practically advantageous, and the lateral link 6 increases the lateral rigidity and reduces the weight. It has the advantage of being able to

The present invention is not limited to the above-mentioned first and second embodiments, and includes various modifications. For example, in each of the above-mentioned embodiments, the case where the invention is applied to the rear suspension of the semi-trailing arm type is described, but it is needless to say that the same can be applied to the case of the full trailing arm type. It is effective for camber control of the rear wheel W of.

[Brief description of drawings]

The drawings illustrate an embodiment of the present invention, and FIGS.
Fig. 1 shows an embodiment, Fig. 1 is a schematic explanatory view showing a rear suspension structure for a right rear wheel, Fig. 2 is a plan view showing a concrete structure, and Fig. 3 is a portion viewed from a direction of an arrow A in Fig. 2. FIG. 4 is a side view, and FIGS. 4 to 6 show a second embodiment, FIG. 4 is an equivalent view of FIG. 1, FIG. 5 is an equivalent view of FIG. 2, and FIG. FIG. 7 is a schematic rear view showing the layout example of the swing center axis of the semi-trailing arm and the vehicle body side rotation center point of the second control link. 1,1 '... semi-trailing arm, 121,121' ... rear wheel support, 14,14 '... elastic bushing, 2 ... camber control link mechanism, 21 ... first control link,
22 ... Second control link, W ... Rear wheel, P ...
Center point of rotation of the second control link on the vehicle body side, l ... Swing center axis of the semi-trailing arm.

Claims (2)

[Claims] 1. A trailing arm which rotatably supports a rear wheel and whose base end is swingably attached to a vehicle body through an elastic bush in a vertical direction, and a rear wheel support of the trailing arm whose base end is the trailing arm. A first control link that is fixed in the vicinity of the front part and extends forward inwardly toward the inside of the vehicle body,
One end is provided at the tip of the first control link, and the other end is provided with a second control link that is rotatably connected to the vehicle body. The second control link is
A rear suspension of an automobile, wherein a center point of rotation of the vehicle body side is installed below the vehicle body by a set amount with respect to a swing center axis line of the trailing arm. 2. The rear suspension of an automobile according to claim 1, wherein the second control link has a length set shorter than the first control link length.