JPH036380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an elastic bushing for elastically supporting a shaft member in an automobile suspension device.

Generally, in an automobile suspension device, a member supporting a wheel, such as a suspension arm, is disposed to extend in the longitudinal direction of the vehicle body between the suspension arm and the vehicle body, and is used to axially receive the external force applied to the wheel in the longitudinal direction of the vehicle body. A shaft member such as a radial rod is provided to share the load.

In order to improve the riding comfort of the automobile, such a shaft member is elastically supported at one end by the vehicle body or suspension arm via a pair of elastic bushings held between the seats. It is designed to absorb external forces applied to the wheels in the longitudinal direction of the vehicle body. However, the above-mentioned elastic bushings do not just need to be soft; if they are too soft, the wheels will wobble and the steering stability will be impaired. That is, from the viewpoint of vibration absorption, it is desirable that the material be soft, and from the viewpoint of steering stability, it is desirable that it be hard.

Conventionally, such elastic bushings have been provided with an insertion hole for inserting the shaft member in the center of the bushing body, and an annular groove or notch on the outer periphery of the bushing body to allow the shaft member to pass through. With respect to axial loads, in the small load region, the grooves and notches are easily deformed and the rigidity is low, and in the medium to high load region, the grooves and notches are completely deformed. Those having nonlinear characteristics that increase rigidity are used.

However, in the above conventional system, no consideration is given to the load in the tilt direction of the shaft member, and the rigidity in that direction is large, so when the suspension arm moves up and down together with the wheel, the shaft member comes into contact with the wall that forms the insertion hole of the bushing body, and the tilting rotation of the shaft member is restricted, resulting in resistance to the vertical swing of the suspension arm and impairing the vibration absorption function of the suspension. There was a problem.

Therefore, in order to solve this problem, an annular notch is provided on the outer periphery of the bushing body, and an annular space is formed between the wall that forms the insertion hole of the bushing body and the shaft member. When a load is applied in the tilt direction of the shaft member, the part of the bushing body on the side of the shaft member in the tilt direction is easily deformed, thereby reducing the rigidity against the load in that direction (see Japanese Utility Model Application Publication No. 54-26222). ) has been proposed. However, in this proposal, due to the provision of the notch and the gap, the overall thickness of the bushing body is thinner, so the rigidity against the axial load of the shaft member is reduced over the entire load range. There is a tendency that the steering stability becomes too small and the steering stability is impaired.

The present invention has been made in view of these points, and as described above, the shaft member of the suspension device disposed in the longitudinal direction of the vehicle body is displaced in the axial direction and tilt rotation direction of the shaft member with respect to the vehicle body. As an elastic bushing capable of supporting elastically, an insertion hole is provided in the center of the bushing body for inserting the shaft member, and an annular sealed space is formed around a wall portion forming the insertion hole. The closed space is filled with an incompressible fluid leaving a void.

As a result, while maintaining optimal non-linear characteristics for both vibration absorption and operational stability against loads in the axial direction of the shaft member without causing excessive rigidity, By reducing the rigidity, the shaft member can be allowed to tilt and rotate, and the vibration absorbing properties of the suspension can be improved.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows a wisdom bone type suspension device to which the present invention is applied, in which 1 indicates an upper arm;
Reference numeral 2 denotes a lower arm, and the inner ends of both arms 1 and 2 are rotatably supported by a vehicle body (not shown). 3 is a damper whose upper end is connected to the vehicle body and whose lower end is connected to the lower arm 2. Reference numeral 4 denotes a knuckle arm whose upper and lower ends are ball jointed to the upper arm 1 and lower arm 2, respectively, and a king pin 5 that rotatably supports a wheel (not shown) projects outward in the center of the knuckle arm 4. A tie rod 6 for rotating the knuckle arm 4 is connected to the side end of the knuckle arm 4.

Further, reference numeral 7 denotes a tension rod extending in the longitudinal direction of the vehicle body, and the tension rod 7
The rear end is connected to the lower arm 2, and the front end is connected to a pair of elastic bushes 8, 8.
It is elastically supported and connected to the bracket 9 on the vehicle body side through the bracket 9, and is provided so as to receive and share the external force applied to the wheel in the longitudinal direction of the vehicle body by means of axial tension.

As shown in detail in FIGS. 2 and 3, the elastic bushing 8 has an insertion hole 10 formed in the center of the rubber bushing body 8a through which the tension rod 7 is inserted. Hole 1
An extension part 8c having a hook-shaped cross section is integrally formed at one end of the wall part 8b forming the 0, and extends around the outside to the end face of the opposite wall part 8b.
An annular sealed space 11 is formed around the wall portion 8b by fixing the tip end thereof to the opposite end surface of the wall portion 8b with an adhesive. The closed space 11
The inside is filled with an incompressible fluid 12 such as silicone rubber, oil, grease, or water, leaving a predetermined space 13. The volume of the void 13 is determined in accordance with the setting of a boundary value between a small load region and a medium to large load region in the axial load of the tension rod 7, which will be described later. In FIG. 2, reference numeral 14 is a catch, and the inner surface of the catch 14 is brought into contact with the elastic bush 8, and the nut 15 is screwed into the threaded portion 7a formed at the end of the tension rod 7. The elastic bush 8 is held in a compressed state. Reference numeral 16 is a collar member for controlling the amount of compression of the elastic bushing 8 and for preventing the bushing 8 from coming into direct contact with the threaded portion 7a of the tension rod 7.

Next, the operation of the above embodiment will be explained.
When a tensile force P is applied in the axial direction of the tension rod 7 from the unloaded state shown in FIG. In a small load area, the body bushing 8
3 is easily compressed while the incompressible fluid 12
moves freely within the annular space 11, the rigidity of the elastic bushing 8 against the load in the axial direction of the tension rod 7 is small. Then, when the above-mentioned air space 13 is compressed and becomes a medium to high load region where most of the closed space 11 is filled with incompressible fluid 12 as shown in FIG. 4, incompressible fluid 12 becomes Since it receives the compressive force from the seat 14, the rigidity of the elastic bushing 8 against the load in the axial direction of the tension rod 7 increases.

In this case, the elastic bushing 8 at the rear of the vehicle body side bracket 9 only expands in the axial direction as the rear catch seat 14, which holds the elastic bushing 8 in a compressed state, moves backward, as shown in FIG. closed space 1
The liquid level of the incompressible fluid 12 in the closed space 11 is lowered, and a relatively large space 13 is formed in the upper part of the closed space 11.

Furthermore, even when a pushing force in the opposite direction to the tensile force P is applied to the tension rod 7, the front and rear bushings simply move in the opposite direction and exhibit similar rigidity characteristics.

In this way, the elastic bushing 8 has a non-linear characteristic in which the stiffness against the load in the axial direction of the tension rod 7, that is, the longitudinal load of the wheel, is small in the small load region and becomes large in the medium to large load region. It is the optimal one that balances both aspects of stability.

On the other hand, when a torsion force Q is applied in the tilt direction of the tension rod 7 as the wheel moves up and down, a compressive force is applied from the seat 14 to the portion of each elastic bushing 8 on the side of the tension rod 7 in the tilt direction. The body bushing 8 is an elastic body bushing because the incompressible fluid 12 in the closed space 11 flows from the tilt direction side of the tension rod 7 to the opposite side, and the closed space 11 on the tilt direction side of the tension rod 7 is easily compressed. Tension rod 8 has low rigidity against loads in the tilt direction. For this reason,
The elastic bush 8 does not restrict the tilt rotation of the tension rod 7, and the lower arm 2 can freely move up and down along with the wheels. As a result, the vibration absorption function of the suspension device can be improved. can.

In the above embodiment, the case where the tension rod 7 and the vehicle body side bracket 9 are connected via the elastic bushing 8 has been explained, but conversely, the case where the tension rod 7 and the lower arm 2 are connected via the elastic bushing is explained. It can also be applied to, and similar effects can be achieved.

Further, the present invention is not limited to the elastic bushing 8 for elastically supporting the tension rod 7 of a wishbone type suspension device as in the above embodiment, but is also applicable to a compression rod of a wishbone type suspension device. In other types of suspension devices, such as stabilizers for strut-type suspension devices, the shaft member disposed in the longitudinal direction of the vehicle body is elastically displaceable in the axial direction and tilt rotation direction of the shaft member with respect to the vehicle body. Of course, the present invention can also be similarly applied to an elastic bush supported on the body.

As explained above, according to the present invention, the shaft member of the suspension device disposed in the longitudinal direction of the vehicle body is elastically supported so as to be displaceable in the axial direction and the tilt rotation direction of the shaft member with respect to the vehicle body. In the elastic bushing, an insertion hole for inserting the shaft member is provided in the center of the bushing body, and an annular sealed space is formed around the wall forming the insertion hole, and a non-compressible Since it is filled with a magnetic fluid leaving a void, it has non-linear characteristics that are optimal for both vibration absorption and handling stability without causing too much rigidity against the axial load of the shaft member. However, it is possible to reduce the rigidity against the load in the tilt direction of the shaft member, allowing the shaft member to tilt and rotate freely to a certain extent, and improving the vibration absorption function of the suspension device. be.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, and FIG. 1 is a schematic perspective view showing a wishbone type suspension device, FIG. 2 is a sectional view of the main part of FIG. 1, and FIG.
Figure 3 is a sectional view taken along the - line in Figure 2;
This figure is a view corresponding to FIG. 2 in which a tensile force is applied in the axial direction of the tension rod, and FIG. 5 is a view corresponding to FIG. 2 in a state in which a torsional force is applied in the tilt direction of the tension rod. 7...Tension rod, 8...Elastic body bushing, 8a...Bushion body, 8b...Wall portion, 10
...Insertion hole, 11... Sealed space, 12... Incompressible fluid, 13... Empty.

Claims (1)

[Claims] 1. An elastic bushing that elastically supports a shaft member of a suspension device disposed in the longitudinal direction of a vehicle body so as to be movable in the axial direction and tilt rotation direction of the shaft member with respect to the vehicle body, the bushing body An insertion hole provided in the center for inserting the shaft member, an annular sealed space formed around the wall forming the insertion hole, and a non-woven material filled with a hole in the sealed space. An elastic bushing comprising a compressed fluid.