JPH0885314A - Axle beam type suspension - Google Patents

Abstract

PURPOSE: To improve antilift performance in a state that roll performance is made excellent. CONSTITUTION: This is an axle beam type suspension having a lateral link 9 and an axle link 14. The second liquid chamber is formed at the upper position of an inner cylinder in a bush 5 provided in the car body side attaching part of a trailing arm 4. The first liquid chamber 13 is composed at an outer position in the car lateral direction to the inner cylinder of a lateral displacement absorbing bush 8. The first and the second liquid chamber communicate mutually through a pipe line 19, and working liquid is filled up in both the liquid chambers and the pipe line 19. An assistant link 14 is erectedly provided between the middle of the lateral link 9 and the axle beam 3 so as to be vertically oscillatable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axle beam type suspension in which left and right rear wheels are connected by an axle beam, and more particularly, an assist link and a lateral displacement absorbing means for suppressing a scuff change caused by a wheel bound and rebound. The present invention relates to an axle beam type suspension equipped with.

[0002]

2. Description of the Related Art As a conventional axle beam type suspension, there is, for example, one described in Japanese Patent Laid-Open No. 5-246223. These axle beam suspensions are suspensions used on the rear side, in which the left and right rear wheels are rotatably supported with respect to the left and right axles, and the left and right axles of the axle beam extend in the vehicle width direction. It is integrally fixed to both left and right ends.

Rear end portions of trailing arms are fixed to the left and right ends of the axle beam, respectively. The left and right trailing arms extend forward of the vehicle body, and their front end portions are connected to the vehicle body side member via bushes. The bush can be vertically swung about the swing center of the bush. Further, the lower ends of the shock absorbers are attached to the left and right ends of the axle beam. Each shock absorber extends upward and its upper end is connected to the vehicle body side member.

Further, as shown in FIGS. 20 and 21, the anisotropic bush 7 is provided on one end side of the axle beam 70.
One end of the lateral link 72 is connected via 1. The lateral link 72 extends substantially in the vehicle width direction, and the other end thereof is connected to a center bracket 74 fixed at the center position of the vehicle body 73 via a bush so as to be vertically swingable.

The anisotropic bush 71 is a bush for absorbing lateral displacement, and has a rubber bush body 71c interposed between an inner cylinder 71a and an outer cylinder 71b. The outer cylinder 71b side is integrally fixed to the end portion of the lateral link 72, and the inner cylinder 71a side is fixed to the axle beam 70. Further, the rigidity of the lateral link 72 in the link axis direction (substantially the vehicle width direction) is set to be low and the rigidity in the direction orthogonal to the link axis (substantially vertical direction) is set to be high, and the lateral direction of the end portion of the lateral link 72 on the axle beam 70 side is set. Rocking is allowed.

An upper end portion of the assist link 75 is vertically swingably connected to the lateral link 72. The assist link 75 is the lateral link 72.
Axle beam 70 with a tilt opposite to that of
The lower end portion is connected to the axle beam 70 so as to be vertically swingable. In the suspension configured as described above, the pair of left and right trailing arms receives the load in the vehicle front-rear direction, and the lateral link 72 and the assist link 75 receive the load in the vehicle width direction.

When the wheel bounces (in-phase stroke) while traveling on an uneven road or the like, the lateral link side attachment point of the assist link 75 is the axle beam 7
Draw an arcuate trajectory centered on the 0 side attachment point. on the other hand,
Assuming that the distance between the attachment points on both ends of the lateral link 72 is constant, the attachment point of the assist link 75 on the lateral link 72 follows an arcuate locus about the axle beam 70 side attachment point of the lateral link 72. In order to draw, a predetermined amount of lateral displacement occurs between the two loci. This lateral displacement is absorbed by the bending of the anisotropic bush 71, as shown in FIG. That is, since the anisotropic bush 71 has low lateral rigidity, the axle beam 7
For the inner cylinder 71a fixed to 0, the lateral link 7
The outer cylinder 71b side fixed to the second side is relatively displaced in the vehicle width direction to be absorbed.

Further, since the lateral link 72 structure is one-point support on the vehicle body side and two-point support on the axle beam 70 side, the positional relationship of the axle beam 70 supported at two points is maintained. As a result, the scuff change when the wheels bounce and rebound to the road surface can be suppressed regardless of the presence or absence of the body roll. Further, even when a lateral force is applied to the ground contact point of the wheel when the wheel bounces from the vehicle body roll state, as shown in FIG.
Since there is no change in the link layout regardless of the body roll,
The vertical force of the lateral link 72 does not generate a jack-up force for lifting the vehicle body from the vehicle body side mounting portion.

[0009]

In the conventional axle beam 70 type suspension as described above, even when the vehicle rolls or when the vehicle body is braked and pitching occurs. That is, the height of the bush attachment point at the front end of the trailing arm, which constitutes the center of vertical swing of the wheels, is the same whether the left and right wheels make the same phase stroke or the opposite phase stroke. .

However, in order to improve the vehicle stability by using the understeer as the roll steer during rolling, it is desired to set the height of the vehicle body side mounting point of the trailing arm, which is the center of the vertical swing, to a low value. If the height of the vehicle body side attachment point is lowered, the anti-lift performance during braking deteriorates. Next, the reason will be described in detail.

First, considering the roll (reverse phase stroke), as shown in FIG. 23 (a), the wheel 80 is centered on the vehicle body side attachment point 81 of the trailing arm 77, and this attachment point 81 and the axle beam are arranged. An arc motion is performed up and down with a line connecting the beam shearing centers located immediately above 70 as a radius. At this time, by mounting the trailing arm 77 so that the vehicle body side attachment point 81 of the trailing arm 77 is lower than the shearing center 82 (inclined forward) in the initial state, the vehicle body rolls and the outer ring 83 bounces. When the inner ring 84 rebounds, the plan view of FIG.
As shown in (b), the outer wheel 83 side moves to the front of the vehicle body, and the inner wheel 84 side moves to the vehicle rear side. As a result, the axle beam 70 is angled in the longitudinal direction of the vehicle body, and a toe change occurs in the toe-in direction. That is, the trailing arm 7
The roll steer is increased and the vehicle stability is improved by increasing the forward inclination angle of mounting 7, that is, lowering the front end mounting portion of the trailing arm 77.

On the other hand, at the time of braking, a pitching motion occurs in which the rear side is lifted by the in-phase stroke to cause a tail lift. When the foot brake is applied, the braking force exerts a moment M about the brake center at the height of the center of gravity on the line dividing the wheel base by the brake distribution, and the vehicle body tries to rotate in the vertical direction. Since the input point of the braking force to this suspension is the ground contact point of the rear wheel, the pitching moment M is expressed by the following equation based on FIG.

M = B × A = B × (H−L · tan θ) where B is the braking force input to the ground contact point of the rear wheel, A is the arm of moment M, and H is the height of the center of gravity of the vehicle. L is the distance in the vehicle front-rear direction from the ground contact point of the rear wheels to the brake center. Θ is the inclination from the ground contact surface in the normal direction with respect to the locus of the ground contact point of the rear wheels. The larger the inclination θ from the contact surface is, the smaller the moment M is, that is, the pitching during braking is reduced. In order to increase the inclination θ, it is preferable that the vertical swing center of the rear wheel, that is, the front end mounting portion of the trailing arm 77 is high (see FIG. 25).

As described above, in consideration of the stability during rolling, it is preferable that the mounting point 81 of the trailing arm 77 on the vehicle body side is low, but in view of the anti-lift performance during braking, the vehicle body of the trailing arm 77 is considered. The higher the side attachment point 81 is, the better the two are in conflict. Therefore, the conventional axle beam suspension cannot improve both the roll steer during rolling and the anti-lift performance during braking.

In view of the above problems, the present invention aims to improve anti-lift performance in a state where roll performance is good.

[0016]

In order to achieve the above object, an axle beam type suspension according to a first aspect of the present invention includes an axle beam that extends in the vehicle width direction and connects left and right wheels. , A pair of left and right trailing arms that are connected to the axle beam and extend forward in the front-rear direction of the vehicle body, and whose front end portions are swingable in the up-down direction and that are connected to a member on the vehicle body side via bushes, and in the vehicle width direction. A lateral link that extends and connects the axle beam and the vehicle body-side member so as to be vertically swingable, and is interposed in a connecting portion between the lateral link and the axle beam and has high rigidity in a substantially vertical direction. In addition, the rigidity of the lateral direction is set to be low, and the lateral displacement absorbing boot that allows the lateral displacement of the lateral link in the lateral direction at the axle beam side attachment point of the lateral link as the lateral link swings up and down. And an assist link connecting the midway position of the lateral link and the axle beam in a vertically swingable manner, the lateral displacement absorbing bush has a rubber bush body between the inner cylinder and the outer cylinder. The outer cylinder side is fixed to the lateral link and the inner cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm is interposed between the inner cylinder and the outer cylinder. In the axle beam type suspension in which the rubber bush main body is interposed between the outer cylinder side and the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the lateral displacement absorbing bush is more than the inner cylinder. A first liquid chamber provided at the rubber bush main body position on the outer side in the vehicle width direction and having a fluid therein and capable of expanding and contracting, and a bush provided at the front end of the trailing arm. A second liquid chamber that is provided at a position above the inner cylinder of the rubber bush main body and has a fluid therein and is expandable / contractible, and fluid can flow back and forth between the first liquid chamber and the second liquid chamber. The feature is that a communication passage communicating with each other is provided.

According to a second aspect of the present invention, in an axle beam type suspension, an axle beam extending in the vehicle width direction and connecting left and right wheels and a front and rear direction of the vehicle body connected to the axle beam are provided. And a pair of left and right trailing arms that connect the front end portion to the vehicle body side member via a bush so as to be swingable in the vertical direction, and the axle beam and the vehicle body side member that extend substantially in the vehicle width direction. And a lateral link that vertically swingably connects between and, and is installed in the connecting portion between the lateral link and the axle beam, and has a high rigidity in the substantially vertical direction and a low rigidity in the substantially vehicle width direction, A lateral displacement absorbing bush that allows the lateral displacement in the vehicle width direction of the attachment point on the axle beam side of the lateral link that accompanies the vertical swing of the lateral link, and the midway position of the lateral link. The lateral displacement absorbing bush is configured by interposing a rubber bush main body between an inner cylinder and an outer cylinder, and an outer link The side is fixed to the lateral link and the inner cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm is
In the axle beam type suspension in which a rubber bush main body is interposed between the inner cylinder and the outer cylinder, the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the lateral displacement A first liquid chamber, which is provided at a rubber bush main body position on the inner side in the vehicle width direction with respect to the inner cylinder of the absorbing bush, has a fluid inside and is expandable and contractible;
A second liquid chamber, which is provided at the rubber bush main body position below the inner cylinder of the bush provided at the front end of the trailing arm, has a fluid therein and is expandable and contractible, the first liquid chamber, and the second liquid chamber. It is characterized in that a communication passage is provided so that the fluid can freely flow between the two liquid chambers.

According to a third aspect of the present invention, in an axle beam type suspension, an axle beam extending in the vehicle width direction and connecting left and right wheels, and a front and rear direction forward direction of the vehicle body connected to the axle beam. And a pair of left and right trailing arms that connect the front end portion to the vehicle body side member via a bush so as to be swingable in the vertical direction, and the axle beam and the vehicle body side member that extend substantially in the vehicle width direction. And a lateral link that vertically swingably connects between and, and is installed in the connecting portion between the lateral link and the axle beam, and has a high rigidity in the substantially vertical direction and a low rigidity in the substantially vehicle width direction, A lateral displacement absorbing bush that allows the lateral displacement in the vehicle width direction of the attachment point on the axle beam side of the lateral link that accompanies the vertical swing of the lateral link, and the midway position of the lateral link. The lateral displacement absorbing bush is configured by interposing a rubber bush main body between an inner cylinder and an outer cylinder, The side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm has a rubber bush body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the rubber bush body position on the inner side in the vehicle width direction of the inner cylinder of the lateral displacement absorbing bush is A first liquid chamber having a fluid therein and capable of expanding and contracting, and a rubber bush located above the inner cylinder of the bush provided at the front end of the trailing arm. A second liquid chamber that is provided at a body position and has a fluid therein and is expandable and contractible, and a communication passage that communicates between the first liquid chamber and the second liquid chamber so that the fluid can flow back and forth. I am trying.

According to a fourth aspect of the present invention, in an axle beam type suspension, an axle beam extending in the vehicle width direction and connecting left and right wheels, and a front and rear direction of the vehicle body connected to the axle beam are provided. And a pair of left and right trailing arms that connect the front end portion to the vehicle body side member via a bush so as to be swingable in the vertical direction, and the axle beam and the vehicle body side member that extend substantially in the vehicle width direction. And a lateral link that vertically swingably connects between and, and is installed in the connecting portion between the lateral link and the axle beam, and has a high rigidity in the substantially vertical direction and a low rigidity in the substantially vehicle width direction, A lateral displacement absorbing bush that allows the lateral displacement in the vehicle width direction of the attachment point on the axle beam side of the lateral link that accompanies the vertical swing of the lateral link, and the midway position of the lateral link. The lateral displacement absorbing bush is configured by interposing a rubber bush main body between an inner cylinder and an outer cylinder, The side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm is
In the axle beam type suspension in which a rubber bush main body is interposed between the inner cylinder and the outer cylinder, the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the lateral displacement A first liquid chamber that is provided at a rubber bush main body position on the outer side in the vehicle width direction with respect to the inner cylinder of the absorbing bush, has a fluid inside, and is expandable and contractible;
A second liquid chamber, which is provided at the rubber bush main body position below the inner cylinder of the bush provided at the front end of the trailing arm, has a fluid therein and is expandable and contractible, the first liquid chamber, and the second liquid chamber. It is characterized in that a communication passage is provided so that the fluid can freely flow between the two liquid chambers.

According to a fifth aspect of the present invention, in an axle beam type suspension, an axle beam extending in the vehicle width direction and connecting left and right wheels, and a front and rear direction of a vehicle body connected to the axle beam are provided. And a pair of left and right trailing arms that connect the front end portion to the vehicle body side member via a bush so as to be swingable in the vertical direction, and the axle beam and the vehicle body side member that extend substantially in the vehicle width direction. And a lateral link that vertically swingably connects between and, and is installed in the connecting portion between the lateral link and the axle beam, and has a high rigidity in the substantially vertical direction and a low rigidity in the substantially vehicle width direction, A lateral displacement absorbing bush that allows the lateral displacement in the vehicle width direction of the attachment point on the axle beam side of the lateral link that accompanies the vertical swing of the lateral link, and the midway position of the lateral link. The lateral displacement absorbing bush is configured by interposing a rubber bush main body between an inner cylinder and an outer cylinder, The side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm is
In the axle beam suspension in which a rubber bushing main body is interposed between the inner cylinder and the outer cylinder, the inner cylinder side is fixed to the trailing arm and the outer cylinder side is fixed to the vehicle body side member, the lateral displacement A first liquid chamber, which is provided at a rubber bush main body position on the inner side in the vehicle width direction with respect to the inner cylinder of the absorbing bush, has a fluid inside and is expandable and contractible;
A second liquid chamber, which is provided at the rubber bush main body position below the inner cylinder of the bush provided at the front end of the trailing arm, has a fluid therein and is expandable and contractible, the first liquid chamber, and the second liquid chamber. It is characterized in that a communication passage is provided so that the fluid can freely flow between the two liquid chambers.

According to a sixth aspect of the present invention, in an axle beam type suspension, an axle beam extending in a vehicle width direction and connecting left and right wheels, and a front and rear direction forward direction of the vehicle body connected to the axle beam. And a pair of left and right trailing arms that connect the front end portion to the vehicle body side member via a bush so as to be swingable in the vertical direction, and the axle beam and the vehicle body side member that extend substantially in the vehicle width direction. And a lateral link that vertically swingably connects between and, and is installed in the connecting portion between the lateral link and the axle beam, and has a high rigidity in the substantially vertical direction and a low rigidity in the substantially vehicle width direction, A lateral displacement absorbing bush that allows the lateral displacement in the vehicle width direction of the attachment point on the axle beam side of the lateral link that accompanies the vertical swing of the lateral link, and the midway position of the lateral link. The lateral displacement absorbing bush is configured by interposing a rubber bush main body between an inner cylinder and an outer cylinder, The side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm has a rubber bush body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the inner cylinder side is fixed to the trailing arm and the outer cylinder side is fixed to the vehicle body side member, the rubber bush body position on the outer side in the vehicle width direction of the inner cylinder of the lateral displacement absorbing bush is A first liquid chamber having a fluid therein and capable of expanding and contracting, and a rubber bush located above the inner cylinder of the bush provided at the front end of the trailing arm. A second liquid chamber that is provided at a body position and has a fluid therein and is expandable and contractible, and a communication passage that communicates between the first liquid chamber and the second liquid chamber so that the fluid can flow back and forth. I am trying.

[0022]

In the axle beam type suspension having the structure described in claim 1 of the present invention, the lateral link structure is supported at one point on the vehicle body side. Therefore, at the time of roll behavior, the vehicle body rolls (a reverse phase stroke) around one point on the vehicle body side, and lateral displacement is not input to the axle beam side attachment point of the lateral link.

Therefore, there is no change in the volume of the first liquid chamber provided in the lateral displacement absorbing bush. Therefore, the volume of the second liquid chamber communicating with the first liquid chamber also does not change. For this,
The height of the trailing arm mounting part at the front end is the height at the time of initial setting. On the other hand, during bounce or pitch behavior (in-phase stroke), such as during braking, the lateral side attachment point of the assist link draws an arcuate trajectory centered on the axle beam side attachment point. On the other hand, assuming that the distance between the attachment points on both ends of the lateral link is constant, the assist link attachment point on the lateral link draws an arc-shaped trajectory up and down around the axle beam side attachment point of the lateral link. Therefore, a predetermined amount of lateral displacement occurs between the two loci. This displacement is
It is absorbed by the lateral absorption bushes.

At this time, when the wheels rebound,
The vehicle body side attachment point on the lateral link is displaced inward in the vehicle width direction to absorb the lateral displacement, and when the wheel bounces, the vehicle body side attachment point on the lateral link is displaced outward in the vehicle width direction. By doing so, the lateral displacement is absorbed. Therefore, when the wheels rebound (in-phase stroke) due to braking or the like, the outer cylinder side fixed to the lateral link side is relatively inward in the vehicle width direction with respect to the inner cylinder fixed to the axle beam. Displace. As a result, the rubber bush body is relatively compressed at the vehicle width direction outer side position of the inner cylinder, and the volume of the first liquid chamber formed at that position is reduced. For this reason, a part of the liquid in the first liquid chamber is supplied to the second liquid chamber via the conduit, and the second liquid chamber is expanded.

Therefore, in the bush provided at the front end portion of the trailing arm, the rubber bush main body portion at the upper position of the inner cylinder fixed to the vehicle body side is expanded so that the outer cylinder is different from the inner cylinder. Are displaced relative to each other. At this time,
Since the inner cylinder is fixed to the vehicle body side, the front end of the trailing arm is displaced upward. Moreover, in the axle beam type suspension having the structure described in claim 2 of the present invention, the lateral link structure is supported at one point on the vehicle body side. Therefore, during roll behavior, the vehicle body rolls around one point on the vehicle body side, and lateral displacement is not input to the attachment point on the axle beam side of the lateral link.

Therefore, the volume of the first liquid chamber provided in the lateral displacement absorbing bush does not change. Therefore, the volume of the second liquid chamber communicating with the first liquid chamber also does not change. For this,
The height of the trailing arm mounting part at the front end is the height at the time of initial setting. On the other hand, during bounce or pitch behavior such as during braking, the lateral attachment point of the assist link draws an arcuate trajectory centered on the axle beam attachment point. On the other hand, assuming that the distance between the attachment points on both ends of the lateral link is constant, the assist link attachment point on the lateral link draws an arc-shaped trajectory up and down around the axle beam side attachment point of the lateral link. Therefore, a predetermined amount of lateral displacement occurs between the two loci. However, this displacement is absorbed by the lateral absorption bushes.

At this time, when the wheels rebound,
The vehicle body side attachment point on the lateral link is displaced inward in the vehicle width direction to absorb the lateral displacement, and when the wheel bounces, the vehicle body side attachment point on the lateral link is displaced outward in the vehicle width direction. By doing so, the lateral displacement is absorbed. So when the wheels rebound together,
The outer cylinder side fixed to the lateral link side is relatively displaced inward in the vehicle width direction with respect to the inner cylinder fixed to the axle beam. As a result, the rubber bush main body at the inner position in the vehicle width direction of the inner cylinder is relatively expanded, and the volume of the first liquid chamber formed at that position is expanded. Therefore, the liquid in the second liquid chamber is supplied to the first liquid chamber via the conduit, and the volume of the second liquid chamber is reduced.

For this reason, in the bush provided at the front end of the trailing arm, the rubber bush main body portion at the lower position of the inner cylinder fixed to the vehicle body side is contracted, and the outer cylinder with respect to the inner cylinder is reduced. Are displaced relative to each other. At this time,
Since the inner cylinder is fixed to the vehicle body side, the front end of the trailing arm is displaced upward. In the axle beam type suspension having the structure described in claim 3 of the present invention, the lateral link structure is supported at one point on the vehicle body side. Therefore, during roll behavior, the vehicle body rolls around one point on the vehicle body side, and lateral displacement is not input to the attachment point on the axle beam side of the lateral link.

Therefore, there is no change in the volume of the first liquid chamber provided in the lateral displacement absorbing bush. Therefore, the volume of the second liquid chamber communicating with the first liquid chamber also does not change. For this,
The height of the trailing arm mounting part at the front end is the height at the time of initial setting. On the other hand, during bounce or pitch behavior such as during braking, the lateral attachment point of the assist link draws an arcuate trajectory centered on the axle beam attachment point. On the other hand, assuming that the distance between the attachment points on both ends of the lateral link is constant, the assist link attachment point on the lateral link draws an arc-shaped trajectory up and down around the axle beam side attachment point of the lateral link. Therefore, a predetermined amount of lateral displacement occurs between the two loci. However, this displacement is absorbed by the lateral absorption bushes.

At this time, when the wheels rebound,
The vehicle body side attachment point on the lateral link is displaced inward in the vehicle width direction to absorb the lateral displacement, and when the wheel bounces, the vehicle body side attachment point on the lateral link is displaced outward in the vehicle width direction. By doing so, the lateral displacement is absorbed. So when the wheels rebound together,
The inner cylinder side fixed to the lateral link side is relatively displaced inward in the vehicle width direction with respect to the outer cylinder fixed to the axle beam. As a result, the rubber bush body is relatively compressed at the inner side position of the inner cylinder in the vehicle width direction, and the volume of the first liquid chamber formed at that position is reduced. For this reason, a part of the liquid in the first liquid chamber is supplied to the second liquid chamber via the conduit, and the second liquid chamber is expanded.

For this reason, in the bush provided at the front end of the trailing arm, the rubber bush main body portion at the upper position of the inner cylinder fixed to the vehicle body side is expanded so that the outer cylinder is different from the inner cylinder. Are displaced relative to each other. At this time,
Since the inner cylinder is fixed to the vehicle body side, the front end of the trailing arm is displaced upward. Further, in the axle beam type suspension having the structure described in claim 4 of the present invention, the lateral link structure is supported at one point on the vehicle body side. Therefore, during roll behavior, the vehicle body rolls around one point on the vehicle body side, and lateral displacement is not input to the attachment point on the axle beam side of the lateral link.

Therefore, the volume of the first liquid chamber provided in the lateral displacement absorbing bush does not change. Therefore, the volume of the second liquid chamber communicating with the first liquid chamber also does not change. For this,
The height of the trailing arm mounting part at the front end is the height at the time of initial setting. On the other hand, during bounce or pitch behavior such as during braking, the lateral attachment point of the assist link draws an arcuate trajectory centered on the axle beam attachment point. On the other hand, assuming that the distance between the attachment points on both ends of the lateral link is constant, the assist link attachment point on the lateral link draws an arc-shaped trajectory up and down around the axle beam side attachment point of the lateral link. Therefore, a predetermined amount of lateral displacement occurs between the two loci. However, this displacement is absorbed by the lateral absorption bushes.

At this time, when the wheels rebound,
The vehicle body side attachment point on the lateral link is displaced inward in the vehicle width direction to absorb the lateral displacement, and when the wheel bounces, the vehicle body side attachment point on the lateral link is displaced outward in the vehicle width direction. By doing so, the lateral displacement is absorbed. So when the wheels rebound together,
The inner cylinder side fixed to the lateral link side is relatively displaced inward in the vehicle width direction with respect to the outer cylinder fixed to the axle beam. As a result, the rubber bush main body at the vehicle width direction outer side position of the inner cylinder is relatively expanded, and the volume of the first liquid chamber formed at that position is expanded. Therefore, the liquid in the second liquid chamber is supplied to the first liquid chamber via the conduit, and the volume of the second liquid chamber is reduced.

For this reason, in the bush provided at the front end of the trailing arm, the rubber bush main body portion at the lower position of the inner cylinder fixed to the vehicle body side is contracted, and the outer cylinder is Are displaced relative to each other. At this time,
Since the inner cylinder is fixed to the vehicle body side, the front end of the trailing arm is displaced upward. In the axle beam type suspension having the configuration described in claim 5 of the present invention, the lateral link structure is supported at one point on the vehicle body side. Therefore, during roll behavior, the vehicle body rolls around one point on the vehicle body side, and lateral displacement is not input to the attachment point on the axle beam side of the lateral link.

Therefore, the volume of the first liquid chamber provided in the lateral displacement absorbing bush does not change. Therefore, the volume of the second liquid chamber communicating with the first liquid chamber also does not change. For this,
The height of the trailing arm mounting part at the front end is the height at the time of initial setting. On the other hand, during bounce or pitch behavior such as during braking, the lateral attachment point of the assist link draws an arcuate trajectory centered on the axle beam attachment point. On the other hand, assuming that the distance between the attachment points on both ends of the lateral link is constant, the assist link attachment point on the lateral link draws an arc-shaped trajectory up and down around the axle beam side attachment point of the lateral link. Therefore, a predetermined amount of lateral displacement occurs between the two loci. However, this displacement is absorbed by the lateral absorption bushes.

At this time, when the wheels rebound,
The vehicle body side attachment point on the lateral link is displaced inward in the vehicle width direction to absorb the lateral displacement, and when the wheel bounces, the vehicle body side attachment point on the lateral link is displaced outward in the vehicle width direction. By doing so, the lateral displacement is absorbed. So when the wheels rebound together,
The inner cylinder side fixed to the lateral link side is relatively displaced inward in the vehicle width direction with respect to the outer cylinder fixed to the axle beam. As a result, the rubber bush body is relatively compressed at the inner side position of the inner cylinder in the vehicle width direction, and the volume of the first liquid chamber formed at that position is reduced. For this reason, a part of the liquid in the first liquid chamber is supplied to the second liquid chamber via the conduit, and the second liquid chamber is expanded.

For this reason, in the bush provided at the front end of the trailing arm, the rubber bush main body below the inner cylinder fixed to the vehicle body is expanded so that the inner cylinder becomes larger than the outer cylinder. Displace relative upwards. At this time, since the outer cylinder is fixed to the vehicle body side, the front end of the trailing arm is displaced upward. Further, in the axle beam type suspension having the structure described in claim 6 of the present invention, the lateral link structure is supported at one point on the vehicle body side. Therefore, during roll behavior, the vehicle body rolls around one point on the vehicle body side, and lateral displacement is not input to the attachment point on the axle beam side of the lateral link.

Therefore, the volume of the first liquid chamber provided in the lateral displacement absorbing bush does not change. Therefore, the volume of the second liquid chamber communicating with the first liquid chamber also does not change. For this,
The height of the trailing arm mounting part at the front end is the height at the time of initial setting. On the other hand, during bounce or pitch behavior such as during braking, the lateral attachment point of the assist link draws an arcuate trajectory centered on the axle beam attachment point. On the other hand, assuming that the distance between the attachment points on both ends of the lateral link is constant, the assist link attachment point on the lateral link draws an arc-shaped trajectory up and down around the axle beam side attachment point of the lateral link. Therefore, a predetermined amount of lateral displacement occurs between the two loci. However, this displacement is absorbed by the lateral absorption bushes.

At this time, when the wheels rebound,
The vehicle body side attachment point on the lateral link is displaced inward in the vehicle width direction to absorb the lateral displacement, and when the wheel bounces, the vehicle body side attachment point on the lateral link is displaced outward in the vehicle width direction. By doing so, the lateral displacement is absorbed. So when the wheels rebound together,
The inner cylinder side fixed to the lateral link side is relatively displaced inward in the vehicle width direction with respect to the outer cylinder fixed to the axle beam. As a result, the rubber bush main body at the vehicle width direction outer side position of the inner cylinder is relatively expanded, and the volume of the first liquid chamber formed at that position is expanded. Therefore, the liquid in the second liquid chamber is supplied to the first liquid chamber via the conduit, and the volume of the second liquid chamber is reduced.

For this reason, in the bush provided at the front end of the trailing arm, the rubber bush main body above the inner cylinder fixed to the vehicle body is reduced in size, and the inner cylinder is separated from the outer cylinder. Displace relative upwards. At this time, since the outer cylinder is fixed to the vehicle body side, the front end of the trailing arm is displaced upward.

[0041]

Embodiments of the present invention will be described with reference to the drawings.
First, the configuration will be described. As shown in FIGS. 1 and 2, the left and right rear wheels 2 are rotatably supported by the left and right axles 1, respectively. The left and right axles 1 are integrally fixed to both left and right ends of an axle beam 3 extending in the vehicle width direction. The axle beam 3 has an inverted U-shape in vertical section, has high rigidity in the front-rear direction and the up-down direction, and has a flexible characteristic with respect to a twisting force, and the left and right wheels are independent. Strokes are flexible.

On the left and right ends of the axle beam 3,
Also, the rear end of each trailing arm 4 is fixed. The left and right trailing arms 4 extend forward of the vehicle body, and their front end portions 4a are connected to a vehicle body side member via a bush 5 so as to be swingable only in the vertical direction. The vehicle body side attachment point of the trailing arm 4 is set so that the axis of the trailing arm 4 extends substantially downward toward the front of the vehicle with an inclination, and the height of the vehicle body side attachment point at the time of initial setting is lowered. It is configured.

As shown in FIG. 3, the bush 5 provided at the front end portion 4a of the trailing arm 4 has an inner cylinder 5a.
The outer cylinder 5b and the outer cylinder 5b are arranged substantially coaxially with their axes oriented in the vehicle width direction, and a rubber bush body 5c made of a rubber body is interposed between the cylinders 5a and 5b. The outer cylinder 5b side is integrally fixed to the front end portion 4a of the trailing arm 4, and the inner cylinder 5a side is fixed to the vehicle body side member.

Inner cylinder 5 of the rubber bush body 5c
A closed hollow portion is formed at a position above a, and the second liquid chamber 6 is formed in the hollow portion. Further, the lower ends of the shock absorbers 7 are integrally attached to the left and right ends of the axle beam 3. The shock absorbers 7 extend upward, and the upper ends of the shock absorbers 7 are connected to the vehicle body side member.

On the one end side of the axle beam 3,
One end of the lateral link 9 is connected via the lateral displacement absorbing bush 8. The lateral link 9 extends substantially in the vehicle width direction, and the other end thereof is connected via a bush 5 to a center bracket 10 fixed to the center position of the vehicle body 11 so as to be vertically swingable. The lateral displacement absorbing bush 8 is
As shown in FIGS. 5 and 6, a rubber bush body 8c is interposed between an inner cylinder 8a and an outer cylinder 8b,
The outer cylinder 8b side is integrally fixed to the lateral link 9, and the inner cylinder 8a side is attached to the axle beam 3 via a bracket. Further, the rubber bush main body 8c is provided with currants 12 at both sides in the vehicle width direction with the inner cylinder 8a sandwiched therebetween (the currants 12 are not shown in FIGS. 6 and 7). The rigidity in the vehicle width direction is set low. Inner cylinder 8 of the currant 12
Those outside the vehicle width direction with respect to a are closed spaces,
A first liquid chamber 13 is formed in the closed space.

As a result, the lateral link 9 is allowed to swing laterally with respect to the end portion of the lateral link 9 on the axle beam 3 side. The first liquid chamber 13 and the second liquid chamber 6 have a conduit 19
Through the liquid chambers 13 and 6 and the conduit 19
The inside is filled with hydraulic fluid. In addition, an upper end portion of the assist link 14 is connected in the middle of the lateral link 9 so as to be vertically swingable. The assist link 14 extends toward the axle beam 3 with an inclination in a direction opposite to the inclination of the lateral link 9, and a lower end portion thereof is connected to the axle beam 3 so as to be vertically swingable.

In the suspension having the above structure,
A pair of left and right trailing arms 4 is used to apply a load in the front-back direction
At the same time, the lateral link 9 and the assist link 14 receive the load in the vehicle width direction. Further, when the wheel bounces (in-phase stroke) while traveling on an uneven road or the like, the lateral side attachment point of the assist link 14 draws an arcuate locus centered on the axle beam 3 side attachment point. On the other hand, assuming that the distance between the attachment points at both ends of the lateral link 9 is constant, the lateral link 9
The attachment point of the upper assist link 14 is the lateral link 9.
In order to draw an arcuate locus around the attachment point on the axle beam 3 side, a predetermined amount of lateral displacement occurs between the two loci.

However, since the attachment point of the lateral link 9 on the axle beam 3 side is set to be displaceable in the lateral direction by the lateral displacement absorbing bush 5, the lateral displacement is absorbed by the bending of the lateral displacement absorbing bush 8. To be done. That is, since the lateral displacement absorbing bush 8 has low lateral rigidity, the outer cylinder 8b side fixed to the lateral link 9 side is relatively approximately the vehicle width with respect to the inner cylinder 8a fixed to the axle beam 3. It is absorbed by being displaced in the direction.

Further, since the lateral link 9 structure is one-point support on the vehicle body side and two-point support on the axle beam 3 side, the positional relationship on the side of the axle beam 3 supported at two points is maintained. Thereby, the scuff change when the wheel bounces to the road surface is suppressed regardless of the presence or absence of the vehicle body roll. Further, when the wheel bounces and rebounds from the vehicle body roll state and the lateral force is applied to the grounding point of the vehicle wheel, the link arrangement does not change regardless of the vehicle body roll. There is no jack-up force to lift the vehicle body from the side mounting part.

Here, since the lateral link structure in the suspension of this embodiment is supported at one point on the vehicle body side, during roll behavior, the vehicle body rolls around this one point on the vehicle body side, and the axle beam of the lateral link 9 is rolled. Three
No lateral displacement is input at the side mounting point. Therefore, since the volume of the first liquid chamber 13 provided in the lateral displacement absorbing bush 8 does not change, the volume of the second liquid chamber 6 communicating with the first liquid chamber 13 also does not change. For this reason, the height of the front end mounting portion of the trailing arm 4 is the height at the time of initial setting.

Since the trailing arm 4 mounting point on the vehicle body side is initially set low, that is, the axis of the trailing arm 4 is tilted forward, the vehicle body rolls and the outer wheel bounces and the inner wheel is bounded. When the vehicle rebounds, when viewed in a plan view, the outer wheel is displaced forward of the vehicle body and the inner wheel is displaced rearward of the vehicle body, which causes the axle beam 3 to have an inclination angle in the vehicle front-rear direction and the rear wheel 2 side toe changes in the toe-in direction. It happens and becomes understeer. As a result, the suspension of this embodiment has good stability during roll behavior.

On the other hand, when the rear side is lifted due to the pitch behavior caused by braking, as described above, the attachment point of the lateral link 9 on the side of the axle beam 3 bends the lateral absorption bush 5. Is displaced substantially in the vehicle width direction. At this time, when the wheels rebound (in-phase stroke), the inner cylinder 8a fixed to the axle beam 3
On the other hand, the outer cylinder 8b side fixed to the lateral link 9 side is relatively displaced inward in the vehicle width direction. by this,
As shown in FIG. 7, the rubber bush body 8c at the vehicle width direction outer side position of the inner cylinder 8a is relatively compressed, and the volume of the first liquid chamber 13 formed at that position is reduced. For this,
Part of the liquid contained in the first liquid chamber 13 is supplied to the second liquid chamber 6 via the conduit, and the second liquid chamber 6 is expanded as shown in FIG.

For this reason, in the bush 5 provided with the front end portion 4a of the trailing arm 4, the rubber bush body 5c at the upper position of the inner cylinder 5a fixed to the vehicle body side is expanded, and the inner cylinder 5a is expanded. On the other hand, the outer cylinder 5b is displaced relatively upward. At this time, since the inner cylinder 5a is fixed to the vehicle body side, the front end portion 4a of the trailing arm 4 is displaced upward.

Thus, when the vehicle is braked and the rear part of the vehicle body is lifted, that is, when the rear wheel 2 rebounds, the front end mounting point of the trailing arm 4 is displaced upward as described above, and the wheel is vertically moved. The instantaneous center of rotation in motion is displaced upward. For this reason, the anti-lift performance during braking is improved, and the tail lift during braking is suppressed. That is,
The instantaneous center of rotation of the rear wheel 2 moves upward during braking, the anti-lift performance improves, and the behavior during braking stabilizes.

Next, the second embodiment will be described. Second
The basic configuration of the suspension of the embodiment is the same as that of the first embodiment described above, and only the arrangement positions of the first liquid chamber 20 and the second liquid chamber 21 are different. In the second embodiment, the first liquid chamber 20 has a lateral displacement absorbing bush 8 as shown in FIG.
Is formed at the position of the rubber bush main body 8c which is located inward of the inner cylinder 8a in the vehicle width direction. Further, as shown in FIG. 10, the second liquid chamber 21 is formed in the bush 5 of the front end portion 4a of the trailing arm 4 at the position of the rubber bush body 5c below the inner cylinder 5a. Other configurations are similar to those of the first embodiment. Note that, in FIGS. 8 and 9, the currant 12 is not shown.

In the suspension of the second embodiment, the lateral link 9 structure is supported at one point on the vehicle body side, as in the above-described embodiment. Therefore, during roll behavior, the vehicle body rolls around one point on the vehicle body side. , Lateral displacement is not input to the attachment point of the lateral link 9 on the axle beam 3 side. Therefore, the first liquid chamber 2 provided in the lateral displacement absorbing bush 8
Since the volume of 0 does not change, the volume of the second liquid chamber 21 communicating with the first liquid chamber 20 also does not change. For this reason, the height of the front end mounting portion of the trailing arm 4 is the height at the time of initial setting.

The mounting point of the trailing arm 4 on the vehicle body side is initially set low, that is, the axis of the trailing arm 4 is tilted forward, so that the vehicle body rolls and the outer wheel bounces and the inner wheel rebounds. Then, when seen in a plan view, the outer wheel is displaced forward of the vehicle body and the inner wheel is displaced rearward of the vehicle body, whereby the axle beam 3 has a tilt angle in the vehicle front-rear direction, and the rear wheel 2 side undergoes a toe change in the toe-in direction. It becomes understeer. As a result, the suspension of this embodiment has good stability during roll behavior.

On the other hand, when braking causes a pitching behavior and the rear side lifts, as described above, the attachment point of the lateral link 9 on the axle beam 3 side is bent by the lateral absorption bush 5. Is displaced substantially in the vehicle width direction. At this time, when the wheels rebound (in-phase stroke), as shown in FIG. 9, the outer cylinder 8b side fixed to the lateral link 9 side is relatively close to the inner cylinder 8a fixed to the axle beam 3. Displaces inward in the width direction. As a result, the rubber bush body 8c at the inner position in the vehicle width direction of the inner cylinder 8a is relatively extended, and the volume of the first liquid chamber 20 formed at that position is increased. For this,
A part of the liquid in the second liquid chamber 21 is moved to the first liquid chamber 20 via the conduit, and the second liquid chamber 21 is reduced.

For this reason, in the bush 5 provided with the front end portion 4a of the trailing arm 4, as shown in FIG. 11, the rubber bush body 5c at the lower position of the inner cylinder 5a fixed to the vehicle body side. Is reduced and the outer cylinder 5b is displaced upward relative to the inner cylinder 5a. At this time, since the inner cylinder 5a is fixed to the vehicle body side, the front end portion 4a of the trailing arm 4 is displaced upward.

As described above, when the vehicle is braked and the rear part of the vehicle body is lifted, that is, when the rear wheel 2 rebounds, the mounting point of the front end of the trailing arm 4 is displaced upward as described above, and the wheel is vertically moved. The instantaneous center of rotation in motion is displaced upward. For this reason, the anti-lift performance during braking is improved, and the lift during braking is suppressed. That is, the instantaneous center of rotation of the rear wheel 2 during braking moves upward, the anti-lift performance improves, and the behavior during braking stabilizes.

Other functions and effects are similar to those of the first embodiment. Next, a third embodiment will be described. The basic configuration of the suspension of the third embodiment is the same as that of the first embodiment described above, and only the configuration of the lateral displacement absorbing bush and the arrangement position of the first liquid chamber are different.

In the lateral displacement absorbing bush 8 of the third embodiment, as shown in FIG. 12, the outer cylinder 8b side is fixed to the axle beam 3 via a bracket, and the inner cylinder 8a side is fixed via a mounting bolt. And is connected to an end of the lateral link 9. Further, the first liquid chamber 30 formed in the lateral displacement absorbing bush 8 is formed at a position of the rubber bush main body 8c which is an inner position in the vehicle width direction with respect to the inner cylinder 8a. Other configurations are similar to those of the first embodiment.
Note that, in FIGS. 12 and 13, the illustration of the currant 12 is omitted.

In the suspension of the third embodiment, the lateral link 9 structure is supported at one point on the vehicle body side as in the case of the above-described embodiment. Therefore, during roll behavior, the vehicle body rolls around the one point on the vehicle body side. Later link 9
No lateral displacement is input at the attachment point on the axle beam 3 side. Therefore, the first
Since the volume of the liquid chamber 30 does not change, the volume of the second liquid chamber 21 communicating with the first liquid chamber 30 also does not change. For this,
The height of the front end mounting portion of the trailing arm 4 is the height at the time of initial setting.

The mounting point of the trailing arm 4 on the vehicle body side is initially set low, that is, the axis of the trailing arm 4 is set to tilt forward, so that the vehicle body rolls and the outer wheel bounces and the inner wheel rebounds. Then, when seen in a plan view, the outer wheel is displaced forward of the vehicle body and the inner wheel is displaced rearward of the vehicle body, whereby the axle beam 3 has a tilt angle in the vehicle front-rear direction, and the rear wheel 2 side undergoes a toe change in the toe-in direction. It becomes understeer. As a result, the suspension of this embodiment has good stability during roll behavior.

On the other hand, when the rear side is lifted due to the pitch behavior caused by the braking, as described above, the attachment point of the lateral link 9 on the side of the axle beam 3 causes the lateral absorption bush 5 to bend. Is displaced substantially in the vehicle width direction. At this time, when the wheels rebound (in-phase stroke), as shown in FIG. 13, the axle beam 3
The inner cylinder 8a side fixed to the lateral link 9 side is relatively displaced inward in the vehicle width direction with respect to the outer cylinder 8b fixed to. As a result, the rubber bush body 8c at the vehicle width direction inner side position of the inner cylinder 8a is relatively compressed, and the volume of the first liquid chamber 30 formed at that position is reduced. For this reason, a part of the liquid that was in the first liquid chamber 30 is transferred to the second
The first liquid chamber 30 is expanded by moving to the liquid chamber 21.

For this reason, in the bush 5 provided with the front end portion 4a of the trailing arm 4, as shown in FIG. 4, the rubber bush body 5c at the upper position of the inner cylinder 5a fixed to the vehicle body side is provided. The outer cylinder 5 is expanded to the inner cylinder 5a.
b is displaced relatively upward. At this time, since the inner cylinder 5a is fixed to the vehicle body side, the front end portion 4a of the trailing arm 4 is displaced upward.

As described above, when the vehicle is braked and the rear part of the vehicle body is lifted, that is, when the rear wheel 2 rebounds, the mounting point of the front end of the trailing arm 4 is displaced upward as described above, and the upper and lower sides of the wheel are moved. The instantaneous center of rotation in motion is displaced upward. For this reason, the anti-lift performance during braking is improved, and the lift during braking is suppressed. That is, the instantaneous center of rotation of the rear wheel 2 during braking moves upward, the anti-lift performance improves, and the behavior during braking stabilizes.

Other functions and effects are similar to those of the first embodiment. Next, a fourth embodiment will be described. The basic structure of the suspension of the fourth embodiment is the same as that of the second embodiment, except that the structure of the lateral displacement absorbing bush and the arrangement position of the first liquid chamber are different.

In the lateral displacement absorbing bush 8 of the fourth embodiment, as shown in FIG. 14, the outer cylinder 8b side is fixed to the axle beam 3 via a bracket, and the inner cylinder 8a side is fixed via a mounting bolt. And is connected to an end of the lateral link 9. Further, the first liquid chamber 40 formed in the lateral displacement absorbing bush 8 is formed at a position of the rubber bush main body 8c which is an outer position in the vehicle width direction with respect to the inner cylinder 8a. The other structure is the same as that of the second embodiment.
Note that, in FIGS. 14 and 15, the currant 12 is not shown.

In the suspension of the fourth embodiment, the lateral link 9 structure is supported at one point on the vehicle body side, as in the above-described embodiment, so that the vehicle body rolls around one point on the vehicle body side during roll behavior. , Lateral displacement is not input to the attachment point of the lateral link 9 on the axle beam 3 side. Therefore, the first liquid chamber 4 provided in the lateral displacement absorbing bush 8
Since the volume of 0 does not change, the volume of the second liquid chamber 21 communicating with the first liquid chamber 40 also does not change. For this reason, the height of the front end mounting portion of the trailing arm 4 is the height at the time of initial setting.

The mounting point of the trailing arm 4 on the vehicle body side is initially set low, that is, the axis of the trailing arm 4 is set to tilt forward, so that the vehicle body rolls and the outer wheel bounces and the inner wheel rebounds. Then, when seen in a plan view, the outer wheel is displaced forward of the vehicle body and the inner wheel is displaced rearward of the vehicle body, whereby the axle beam 3 has a tilt angle in the vehicle front-rear direction, and the rear wheel 2 side undergoes a toe change in the toe-in direction. It becomes understeer. As a result, the suspension of this embodiment has good stability during roll behavior.

On the other hand, when the rear side is lifted due to the pitch behavior caused by braking, as described above, the attachment point of the lateral link 9 on the side of the axle beam 3 bends the lateral absorption bush 5. Is displaced substantially in the vehicle width direction. At this time, when the wheels rebound (in-phase stroke), the outer cylinder 8b fixed to the axle beam 3
On the other hand, the inner cylinder 8a side fixed to the lateral link 9 side is relatively displaced inward in the vehicle width direction. by this,
As shown in FIG. 15, the rubber bush main body 8c at the outer position of the inner cylinder 8a in the vehicle width direction is relatively extended, and the volume of the first liquid chamber 40 formed at that position is increased. For this reason, a part of the liquid in the second liquid chamber 21 is transferred to the first via the pipe line.
The second liquid chamber 21 is reduced by being moved to the liquid chamber 40.

Therefore, in the bush 5 provided with the front end portion 4a of the trailing arm 4, as shown in FIG. 11, the rubber bush body 5c at the lower position of the inner cylinder 5a fixed to the vehicle body side. Is reduced and the outer cylinder 5b is displaced upward relative to the inner cylinder 5a. At this time, since the inner cylinder 5a is fixed to the vehicle body side, the front end portion 4a of the trailing arm 4 is displaced upward.

As described above, when the vehicle is braked and the rear part of the vehicle body is lifted, that is, when the rear wheel 2 rebounds, the mounting point of the front end of the trailing arm 4 is displaced upward as described above, and the upper and lower sides of the wheel are vertically moved. The instantaneous center of rotation in motion is displaced upward. For this reason, the anti-lift performance during braking is improved, and the lift during braking is suppressed. That is, the instantaneous center of rotation of the rear wheel 2 during braking moves upward, the anti-lift performance improves, and the behavior during braking stabilizes.

Other functions and effects are similar to those of the second embodiment. Next, a fifth embodiment will be described. The basic structure of the suspension of the fifth embodiment is the same as that of the third embodiment, except that the structure of the bush at the front end of the trailing arm and the arrangement position of the second liquid chamber are different.

In the bush 5 provided at the front end portion 4a of the trailing arm 4 of the fifth embodiment, as shown in FIG. 16, the outer cylinder 5b side is fixed to the vehicle body side via a bracket, and the inner cylinder 5a side is fixed. , And is connected to the front end portion 4a of the trailing arm 4 via mounting bolts. Further, the second liquid chamber 50 formed in the bush 5 is
The rubber bush main body 5c is formed at a position lower than the inner cylinder 5a. Other configurations are similar to those of the third embodiment.

In the suspension of the fifth embodiment, the lateral link 9 structure is supported at one point on the vehicle body side as in the above-described embodiment, so that the vehicle body rolls around one point on the vehicle body side during roll behavior. Later link 9
No lateral displacement is input at the attachment point on the axle beam 3 side. Therefore, the first
Since the volume of the liquid chamber 30 does not change, the volume of the second liquid chamber 50 communicating with the first liquid chamber 30 also does not change. For this,
The height of the front end mounting portion of the trailing arm 4 is the height at the time of initial setting.

The mounting point of the trailing arm 4 on the vehicle body side is initially set low, that is, the axis of the trailing arm 4 is set to tilt forward, so that the vehicle body rolls and the outer wheel bounces and the inner wheel rebounds. Then, when seen in a plan view, the outer wheel is displaced forward of the vehicle body and the inner wheel is displaced rearward of the vehicle body, whereby the axle beam 3 has a tilt angle in the vehicle front-rear direction, and the rear wheel 2 side undergoes a toe change in the toe-in direction. It becomes understeer. As a result, the suspension of this embodiment has good stability during roll behavior.

On the other hand, when the rear side is lifted due to the pitch behavior caused by the braking, as described above, the attachment point of the lateral link 9 on the side of the axle beam 3 causes the lateral absorption bush 5 to bend. Is displaced substantially in the vehicle width direction. At this time, when the wheels rebound (in-phase stroke), the outer cylinder 8b fixed to the axle beam 3
On the other hand, the inner cylinder 8a side fixed to the lateral link 9 side is relatively displaced inward in the vehicle width direction. by this,
As shown in FIG. 13, the rubber bush body 8c at the inner position in the vehicle width direction of the inner cylinder 8a is relatively compressed, and the volume of the first liquid chamber 30 formed at that position is reduced. For this reason, a part of the liquid that was in the first liquid chamber 30 is transferred to the second
The first liquid chamber 30 is expanded by being moved to the liquid chamber 50.

For this reason, in the bush 5 provided with the front end portion 4a of the trailing arm 4, as shown in FIG. 17, the inner cylinder 5a fixed to the trailing arm 4 side is provided.
The lower part of the rubber bush body 5c is expanded,
The inner cylinder 5a is displaced upward relative to the outer cylinder 5b.
At this time, since the outer cylinder 5b is fixed to the vehicle body side, the front end portion 4a of the trailing arm 4 is displaced upward.

As described above, when the vehicle is braked and the rear part of the vehicle body is lifted, that is, when the rear wheel 2 rebounds, the front end mounting point of the trailing arm 4 is displaced upward as described above, and the wheel is vertically moved. The instantaneous center of rotation in motion is displaced upward. For this reason, the anti-lift performance during braking is improved, and the lift during braking is suppressed. That is, the instantaneous center of rotation of the rear wheel 2 during braking moves upward, the anti-lift performance improves, and the behavior during braking stabilizes.

Other functions and effects are the same as those of the third embodiment. Next, a sixth embodiment will be described. The basic structure of the suspension of the sixth embodiment is the same as that of the fourth embodiment, except that the structure of the bush at the front end of the trailing arm and the arrangement position of the second liquid chamber are different.

In the bush 5 provided on the front end portion 4a of the trailing arm 4 of the sixth embodiment, as shown in FIG. 18, the outer cylinder 5b side is fixed to the vehicle body side via a bracket, and the inner cylinder 5a is fixed. The side is connected to the front end 4a of the trailing arm 4 via a mounting bolt. Further, the second liquid chamber 60 formed in the bush 5
Is a rubber bush body 5c located above the inner cylinder 5a.
Is formed in position. The other structure is the same as that of the fourth embodiment.

In the suspension of the sixth embodiment, as in the case of the above-described embodiment, the lateral link 9 structure is supported at one point on the vehicle body side. Therefore, during roll behavior, the vehicle body rolls around this one point on the vehicle body side. , Lateral displacement is not input to the attachment point of the lateral link 9 on the axle beam 3 side. Therefore, the first liquid chamber 4 provided in the lateral displacement absorbing bush 8
Since the volume of 0 does not change, the volume of the second liquid chamber 60 communicating with the first liquid chamber 40 also does not change. For this reason, the height of the front end mounting portion of the trailing arm 4 is the height at the time of initial setting.

The mounting point of the trailing arm 4 on the vehicle body side is initially set low, that is, the axis of the trailing arm 4 is set to tilt forward, so that the vehicle body rolls and the outer wheel bounces and the inner wheel rebounds. Then, when seen in a plan view, the outer wheel is displaced forward of the vehicle body and the inner wheel is displaced rearward of the vehicle body, whereby the axle beam 3 has a tilt angle in the vehicle front-rear direction, and the rear wheel 2 side undergoes a toe change in the toe-in direction. It becomes understeer. As a result, the suspension of this embodiment has good stability during roll behavior.

On the other hand, when the rear side is lifted due to the pitch behavior caused by braking, as described above, the attachment point of the lateral link 9 on the side of the axle beam 3 causes the lateral absorption bush 5 to bend. Is displaced substantially in the vehicle width direction. At this time, if the wheels rebound (in-phase stroke), as shown in FIG. 15, the axle beam 3
The inner cylinder 8a side fixed to the lateral link 9 side is relatively displaced inward in the vehicle width direction with respect to the outer cylinder 8b fixed to. As a result, the rubber bush body 8c at the outer position of the inner cylinder 8a in the vehicle width direction is relatively extended, and the volume of the first liquid chamber 40 formed at that position is increased. For this reason, a part of the liquid in the second liquid chamber 60 is transferred to the first via the conduit.
The second liquid chamber 60 is reduced by being moved to the liquid chamber 40.

Therefore, in the bush 5 provided with the front end portion 4a of the trailing arm 4, as shown in FIG. 19, the inner cylinder 5a fixed to the trailing arm 4 side is provided.
The rubber bush body 5c at the upper position of is contracted, and the inner cylinder 5a is displaced upward relative to the outer cylinder 5b. At this time, since the outer cylinder 5b is fixed to the vehicle body side, the front end portion 4a of the trailing arm 4 is displaced upward.

As described above, when the vehicle is braked and the rear part of the vehicle body is lifted, that is, when the rear wheel 2 rebounds, the front end attachment point of the trailing arm 4 is displaced upward as described above, and the wheel is vertically moved. The instantaneous center of rotation in motion is displaced upward. For this reason, the anti-lift performance during braking is improved, and the lift during braking is suppressed. That is, the instantaneous center of rotation of the rear wheel 2 during braking moves upward, the anti-lift performance improves, and the behavior during braking stabilizes.

Other functions and effects are the same as those in the fourth embodiment.

[0090]

As described above, in the axle beam suspension of the present invention, the anti-lift performance during braking can be improved without sacrificing the understeer characteristic of roll steer. That is, there is an effect that the vehicle stability at the time of braking can be improved while maintaining the vehicle stability at the time of turning the vehicle at the same favorable characteristics as in the conventional case.

[Brief description of drawings]

FIG. 1 is a perspective view showing an axle beam type suspension of a first embodiment according to the present invention.

FIG. 2 is a basic configuration diagram showing an axle beam suspension of a first embodiment according to the present invention.

FIG. 3 is a side view showing a bush at a front end portion of a trailing arm according to the first embodiment of the present invention.

FIG. 4 is a side view showing a state of the bush at the front end portion of the trailing arm according to the first embodiment of the present invention during braking.

FIG. 5 is a diagram showing a relationship between a lateral link, an assist link, and a lateral displacement absorbing bush according to the first embodiment of the present invention.

FIG. 6 is a side view showing a lateral displacement absorbing bush of the first embodiment according to the present invention.

FIG. 7 is a diagram showing a state during braking of the lateral displacement absorbing bush of the first embodiment according to the present invention.

FIG. 8 is a side view showing a bush at a front end portion of a trailing arm according to a second embodiment of the present invention.

FIG. 9 is a side view showing a state at the time of braking the bush at the front end portion of the trailing arm of the second embodiment according to the present invention.

FIG. 10 is a side view showing a lateral displacement absorbing bush of a second embodiment according to the present invention.

FIG. 11 is a diagram showing a state during braking of the lateral displacement absorbing bush of the second embodiment according to the present invention.

FIG. 12 is a side view showing a lateral displacement absorbing bush of a third embodiment according to the present invention.

FIG. 13 is a diagram showing a state during braking of the lateral displacement absorbing bush of the third embodiment according to the present invention.

FIG. 14 is a side view showing a lateral displacement absorbing bush of a fourth embodiment according to the present invention.

FIG. 15 is a diagram showing a state during braking of a lateral displacement absorbing bush of a fourth embodiment according to the present invention.

FIG. 16 is a side view showing a bush at a front end portion of a trailing arm according to a fifth embodiment of the present invention.

FIG. 17 is a side view showing a state at the time of braking the bush at the front end of the trailing arm of the fifth embodiment according to the present invention.

FIG. 18 is a side view showing a bush at a front end portion of a trailing arm according to a sixth embodiment of the present invention.

FIG. 19 is a side view showing a state at the time of braking the bush at the front end portion of the trailing arm of the sixth embodiment according to the present invention.

FIG. 20 is a basic configuration diagram showing a conventional axle beam suspension.

FIG. 21 is a diagram showing the behavior of an anisotropic bush.

FIG. 22 is a diagram showing a state at the time of rolling.

FIG. 23 is a diagram showing the relationship between the roll steer and the trailing arm front end mounting portion.

FIG. 24 is a diagram for explaining a pitch moment during braking.

FIG. 25 is a diagram showing the relationship between the height of the front end of the trailing arm and the locus of the ground contact point.

[Explanation of symbols]

 3 Axle beam 4 Trailing arm 5 Bush 5a Inner cylinder 5b Outer cylinder 5c Rubber bush main body 6 Second liquid chamber 8 Lateral displacement absorbing bush 8a Inner cylinder 8b Outer cylinder 8c Rubber bush main body 9 Lateral link 13 First liquid chamber 14 Assist Link

Claims (6)

[Claims] 1. An axle beam that extends in the vehicle width direction and connects left and right wheels; and an axle beam that is connected to the axle beam and extends forward in the front-rear direction of a vehicle body so that a front end of the axle beam can swing vertically.
A pair of left and right trailing arms connected to the vehicle body side member via a bush, and a lateral link extending substantially in the vehicle width direction and connecting between the axle beam and the vehicle body side member so as to be vertically swingable, The lateral link is connected to the axle beam, and the rigidity in the vertical direction is set to be high and the rigidity in the vehicle width direction is set to be low. As the lateral link vertically swings, the axle beam of the lateral link is set. A lateral displacement absorbing bush capable of allowing lateral displacement of the side mounting point in the vehicle width direction; and an assist link connecting a midway position of the lateral link and the axle beam so as to be vertically swingable. The displacement absorbing bush has a rubber bush body interposed between an inner cylinder and an outer cylinder.
The outer cylinder side is fixed to the lateral link and the inner cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm has a rubber bush main body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the rubber on the outer side in the vehicle width direction than the inner cylinder in the lateral displacement absorbing bush is formed. A first liquid chamber which is provided at the bush main body position and has fluid inside and is expandable and contractible, and a bush provided at the front end of the trailing arm, which is provided at a rubber bush main body position above the inner cylinder, A second liquid chamber that has a fluid therein and is expandable and contractible, and a communication passage that communicates between the first liquid chamber and the second liquid chamber so that the fluid can freely flow in and out are provided. Xul-beam type suspension. 2. An axle beam that extends in the vehicle width direction and connects the left and right wheels; and an axle beam that is connected to the axle beam and extends forward in the front-rear direction of the vehicle body.
A pair of left and right trailing arms connected to the vehicle body side member via a bush, and a lateral link extending substantially in the vehicle width direction and connecting between the axle beam and the vehicle body side member so as to be vertically swingable, The lateral link is connected to the axle beam, and the rigidity in the vertical direction is set to be high and the rigidity in the vehicle width direction is set to be low. As the lateral link vertically swings, the axle beam of the lateral link is set. A lateral displacement absorbing bush capable of allowing lateral displacement of the side mounting point in the vehicle width direction; and an assist link connecting a midway position of the lateral link and the axle beam so as to be vertically swingable. The displacement absorbing bush has a rubber bush body interposed between an inner cylinder and an outer cylinder.
The outer cylinder side is fixed to the lateral link and the inner cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm has a rubber bush main body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the rubber on the inner side in the vehicle width direction than the inner cylinder in the lateral displacement absorbing bush is formed. A first liquid chamber that is provided at the bush body position and has a fluid inside and is expandable and contractible; and a bush provided at the front end of the trailing arm, provided at a rubber bush body position that is lower than the inner cylinder of the bush, A second liquid chamber that has a fluid therein and is expandable and contractible, and a communication passage that communicates between the first liquid chamber and the second liquid chamber so that the fluid can freely flow in and out are provided. Xul-beam type suspension. 3. An axle beam that extends in the vehicle width direction and connects the left and right wheels; and an axle beam that is connected to the axle beam and extends forward in the front-rear direction of the vehicle body.
A pair of left and right trailing arms connected to the vehicle body side member via a bush, and a lateral link extending substantially in the vehicle width direction and connecting between the axle beam and the vehicle body side member so as to be vertically swingable, The lateral link is connected to the axle beam, and the rigidity in the vertical direction is set to be high and the rigidity in the vehicle width direction is set to be low. As the lateral link vertically swings, the axle beam of the lateral link is set. A lateral displacement absorbing bush capable of allowing lateral displacement of the side mounting point in the vehicle width direction; and an assist link connecting a midway position of the lateral link and the axle beam so as to be vertically swingable. The displacement absorbing bush has a rubber bush body interposed between an inner cylinder and an outer cylinder.
The inner cylinder side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end portion of the trailing arm has a rubber bush main body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, a rubber bush on the inner side in the vehicle width direction of the inner cylinder of the lateral displacement absorbing bush is formed. The first liquid chamber, which is provided at the main body position and has fluid inside, and is expandable and contractible, and the bush provided at the front end of the trailing arm, which is provided at the rubber bush main body position above the inner cylinder, The second liquid chamber which has a fluid therein and is expandable and contractible, and a communication passage which communicates between the first liquid chamber and the second liquid chamber so that the fluid can flow freely between the first liquid chamber and the second liquid chamber. Rubeam suspension. 4. An axle beam that extends in the vehicle width direction and connects the left and right wheels, and an axle beam that is connected to the axle beam and extends forward in the front-rear direction of the vehicle body so that the front end portion can swing in the up-down direction.
A pair of left and right trailing arms connected to the vehicle body side member via a bush, and a lateral link extending substantially in the vehicle width direction and connecting between the axle beam and the vehicle body side member so as to be vertically swingable, The lateral link is connected to the axle beam, and the rigidity in the vertical direction is set to be high and the rigidity in the vehicle width direction is set to be low. As the lateral link vertically swings, the axle beam of the lateral link is set. A lateral displacement absorbing bush capable of allowing lateral displacement of the side mounting point in the vehicle width direction; and an assist link connecting a midway position of the lateral link and the axle beam so as to be vertically swingable. The displacement absorbing bush has a rubber bush body interposed between an inner cylinder and an outer cylinder.
The inner cylinder side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm has a rubber bush body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the outer cylinder side is fixed to the trailing arm and the inner cylinder side is fixed to the vehicle body side member, the rubber on the outer side in the vehicle width direction than the inner cylinder in the lateral displacement absorbing bush is formed. A first liquid chamber that is provided at the bush body position and has a fluid inside and is expandable and contractible; and a bush provided at the front end of the trailing arm, provided at a rubber bush body position that is lower than the inner cylinder of the bush, A second liquid chamber that has a fluid therein and is expandable and contractible, and a communication passage that communicates between the first liquid chamber and the second liquid chamber so that the fluid can freely flow in and out are provided. Xul-beam type suspension. 5. An axle beam that extends in the vehicle width direction and connects left and right wheels, and an axle beam that is connected to the axle beam and extends forward in the vehicle front-rear direction, and a front end portion thereof can swing vertically.
A pair of left and right trailing arms connected to the vehicle body side member via a bush, and a lateral link extending substantially in the vehicle width direction and connecting between the axle beam and the vehicle body side member so as to be vertically swingable, The lateral link is connected to the axle beam, and the rigidity in the vertical direction is set to be high and the rigidity in the vehicle width direction is set to be low. As the lateral link vertically swings, the axle beam of the lateral link is set. A lateral displacement absorbing bush capable of allowing lateral displacement of the side mounting point in the vehicle width direction; and an assist link connecting a midway position of the lateral link and the axle beam so as to be vertically swingable. The displacement absorbing bush has a rubber bush body interposed between an inner cylinder and an outer cylinder.
The inner cylinder side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end of the trailing arm has a rubber bush body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the inner cylinder side is fixed to the trailing arm and the outer cylinder side is fixed to the vehicle body side member, the rubber on the inner side in the vehicle width direction than the inner cylinder in the lateral displacement absorbing bush is formed. A first liquid chamber that is provided at the bush body position and has a fluid inside and is expandable and contractible; and a bush provided at the front end of the trailing arm, provided at a rubber bush body position that is lower than the inner cylinder of the bush, A second liquid chamber that has a fluid therein and is expandable and contractible, and a communication passage that communicates between the first liquid chamber and the second liquid chamber so that the fluid can freely flow in and out are provided. Xul-beam type suspension. 6. An axle beam that extends in the vehicle width direction and connects the left and right wheels; and an axle beam that is connected to the axle beam and extends forward in the front-rear direction of the vehicle body.
A pair of left and right trailing arms connected to the vehicle body side member via a bush, and a lateral link extending substantially in the vehicle width direction and connecting between the axle beam and the vehicle body side member so as to be vertically swingable, The lateral link is connected to the axle beam, and the rigidity in the vertical direction is set to be high and the rigidity in the vehicle width direction is set to be low. As the lateral link vertically swings, the axle beam of the lateral link is set. A lateral displacement absorbing bush capable of allowing lateral displacement of the side mounting point in the vehicle width direction; and an assist link connecting a midway position of the lateral link and the axle beam so as to be vertically swingable. The displacement absorbing bush has a rubber bush body interposed between an inner cylinder and an outer cylinder.
The inner cylinder side is fixed to the lateral link and the outer cylinder side is fixed to the axle beam, and the bush provided at the front end portion of the trailing arm has a rubber bush main body interposed between the inner cylinder and the outer cylinder. In the axle beam suspension in which the inner cylinder side is fixed to the trailing arm and the outer cylinder side is fixed to the vehicle body side member, a rubber bush on the vehicle width direction outer side than the inner cylinder in the lateral displacement absorbing bush is formed. The first liquid chamber, which is provided at the main body position and has fluid inside, and is expandable and contractible, and the bush provided at the front end of the trailing arm, which is provided at the rubber bush main body position above the inner cylinder, The second liquid chamber which has a fluid therein and is expandable and contractible, and a communication passage which communicates between the first liquid chamber and the second liquid chamber so that the fluid can flow freely between the first liquid chamber and the second liquid chamber. Rubeam suspension.