JPH04272527A - Bush - Google Patents

Abstract

PURPOSE:To adjust the movement shift of a mass body supported by a bush with high precision by changing the spring characteristic of the load applied on a bush according to the directions of the inputs in two directions. CONSTITUTION:An elastic member 2 is fixed on an inner cylinder 3 or outer cylinder 4, and on one end side in the axis line direction, the first rubber bush 1a is fixed on the side where the elastic member 2 between the inner cylinder 3 or outer cylinder 4, is not fixed and on the other end in the axis line direction, the second rubber bush 1b is fixed on the cylinder on which the elastic member 2 is not fixed. The modulus of the first rubber bush 1a is set smaller in the axis line direction than the modulus of the second rubber bush 1b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bushing that absorbs vibrations input from wheels to a vehicle body and improves riding comfort.

0002

[Prior Art] Generally, in the front suspension of an automobile, each of the left and right wheels is connected to the vehicle body (not shown) by a suspension arm or the like, and a bush is interposed at the connection point between the suspension arm and the vehicle body. It is a well-known technology that absorbs shock input from the road surface and improves ride comfort.
The characteristics required of the bush are as follows, and will be explained using FIG. 6. Figure 6 shows Japanese Patent Application Laid-Open No. 62-10150.
This is the L-shaped suspension arm on the right front wheel side shown in No. 6, and the upper side in the figure is the front side of the vehicle. This L-shaped suspension arm S has a wheel coupling part j connected to the right front wheel on the right side of the figure, and an L-shaped suspension arm S on the left side of the figure.
It is provided with hollow cylindrical upper parts 70 and 80 that are integrally formed with the type suspension arm S, and in particular, inside the cylindrical part 70, bolts and nuts are attached to the vehicle body through bushes 85 as shown in FIG. They are connected. This L-shaped suspension arm S becomes the outer turning wheel when the automobile is turning left in front of the vehicle. At this time, a force is applied to the wheel coupling portion j of the L-shaped suspension arm S in the direction shown by arrow A in the figure (towards the vehicle body) as a road surface reaction force against the centrifugal force received during turning. Therefore, the outer cylinder 100 of the bush 85 placed inside the cylindrical portion 70 receives a force (load) that is pressed in the direction indicated by the arrow a in the figure, that is, in the direction toward the vehicle body side. On the other hand, when the brake is activated while the vehicle is moving forward, a force directed toward the rear of the vehicle as indicated by arrow B in the figure is applied to the wheel coupling portion j. Therefore, the outer cylinder 100 of the bush 85 placed inside the cylindrical part 70 is pressed in the direction shown by arrow b in the figure, that is, in the opposite direction to the vehicle body side, by the moment acting on the L-shaped suspension arm S. power (
load).

[0003] The bush 85 inside the cylindrical part 70 is
A hollow cylindrical outer cylinder 100 whose one end toward the front of the vehicle is formed into a flange shape and forms an element of the L-shaped arm, and a hollow cylindrical shape that is concentric with the outer cylinder 100 on the inner periphery thereof. It is composed of an inner cylinder 90 and a rubber member 110 placed between the outer cylinder 100 and the inner cylinder 90. Rubber member 1
10 is provided with a cavity 120 extending in the direction perpendicular to the plane of the drawing (in the longitudinal direction of the vehicle) on the left side of the inner cylinder 90 in the figure (vehicle body side direction). The elastic constant of the rubber member 110 is the inner cylinder 90 in the figure.
The elastic constant is set smaller than the elastic constant of the rubber member 110 on the right side. Therefore, in conventional suspension systems, the elastic constant of the bushing can be set to ``larger'' or ``smaller'' during turning and braking, respectively, which improves steering stability during turning and ride comfort during braking. Efforts are being made to achieve both.

0004

[Problems to be Solved by the Invention] By the way, when the wheel coupling part j receives a force due to braking, the bushes placed in the cylindrical parts 70 and 80 of the L-shaped suspension arm S are not only moved in the lateral direction of the vehicle body but also It also receives force (load) that presses the vehicle in the longitudinal direction. Here, the force in the side direction of the vehicle body and the force in the longitudinal direction of the vehicle are the L-type suspension arm S
is determined by the shape of and the elastic constant of each bush placed in the cylindrical portions 70, 80. However, like the configuration of the bush 85 in FIG. 7, the rubber member 110 having the cavity 120 in the direction perpendicular to the plane of the drawing (vehicle longitudinal direction),
The elastic constant changes in response to changes in the direction of force in the vehicle body side direction, but does not change in response to changes in the direction of force in the longitudinal direction of the vehicle, so the elastic constant changes in the vehicle longitudinal direction depending on the driving condition. The elastic constants for force are not set sufficiently, and it is not possible to achieve both handling stability and ride comfort. In view of the above, an object of the present invention is to obtain elastic support characteristics that correspond to changes in the direction of the load by setting the directions in which the elastic constant changes depending on the change in the direction of the load to two directions that are orthogonal to each other. shall be.

[0005]

[Means for Solving the Problems] The present invention includes a hollow cylindrical outer cylinder made of a rigid material, and a hollow cylinder placed inside the outer cylinder so as to be parallel to the outer cylinder. The bushing has a rubber bush between the inner cylinder made of a rigid material of An elastic member is fixed to either one of the outer cylinders, and an elastic member is fixed to one end side of the elastic member in the axial direction to the side of the inner cylinder or the outer cylinder to which the elastic member is not fixed. A first rubber bush is placed on the other end side of the elastic member in the axial direction, and a second rubber bush that is fixed to the side of the inner cylinder or the outer cylinder to which the elastic member is not fixed is placed. and the elastic constant of the first rubber bush is set smaller in the axial direction than the elastic constant of the second rubber bush.

[0006]

[Operation] According to the above means, the elastic constant of the rubber bush in one direction is set smaller than the elastic constant in the opposite direction in the axial direction and the direction perpendicular to the axial direction. Therefore, the elastic constants of the bushing in the axial direction and in the direction perpendicular to the axial direction change depending on the direction of the load on a plane consisting of two directions. Note that when an external force is input to the outer cylinder from a direction oblique to both the axial direction and the direction perpendicular to the axial direction, the force is applied to the outer cylinder from a direction opposite to the oblique direction. , the elastic constant of the bushing in each of the axial direction and the direction perpendicular to the axial direction becomes small.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A bush M according to an embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 5. Note that Figure 1 is
FIG. 3 is an external view of a bush M of the present invention. Also, Figure 2 is Figure 1
FIG. 3 is a plan view taken from arrow Q in FIG. 2, and FIG. The bush M consists of an inner cylinder 3 formed of metal in a hollow cylindrical shape as shown in FIG. Rubber bush 1 placed between and outer cylinder 4
, a vibration absorber 5, and an elastic member 2 disposed within the rubber bush 1. In this embodiment, the rubber bush 1, the vibration absorber 5, and the elastic member 2 each have a rubber material as a main component. Rubber bush 1 is
As shown in Fig. 3, it is formed to have the same length as the outer cylinder 4, and is fixed only to the outer cylinder 4, and when viewed from the upward arrow Q in the figure, the circumference of the outer cylinder 4 is It has a shape that fills 3/4 of the inner circumference of the outer cylinder along the direction. In the cross-sectional view of FIG. 3, each of the end portion 1a (first rubber bush) and the end portion 1b (second rubber bush) that appear symmetrically with respect to the coincident axis L of the outer cylinder 4 and the inner cylinder 3 is It is curved convexly to have the same length from both ends of the tube 4 toward the intermediate portion 1c (inward direction of the outer tube 4). In addition, Figure 2,
In FIG. 3, the end portion 1 appears symmetrically with respect to the axis L.
In a, elliptical holes 20a, 20a having the same depth are formed from one end surface of the outer cylinder 4 toward the inside of the outer cylinder 4. These elliptical holes 20a, 20a allow each end 1a, 1
The wall thickness of a is uniform. When the elliptical holes 20a, 20a of the end portion 1a are viewed in the plan view of FIG. There is. FIG. 4 shows a cross-sectional view taken along line B-B in FIG.
c is fixed to the inner peripheral surface of about three-quarters of the outer cylinder 4,
In the figure, the upper portion facing the vibration absorber 5 is thicker and the lateral direction is thinner. Further, the lower left and right ends of the intermediate portion 1c of the rubber bush 1 placed on the inner circumferential surface of the cylindrical portion 4 are formed to be thin toward the center of the inner tube 3. In FIG. 3, a pair of elastic members 2 are arranged so as to fit tightly into an intermediate portion 1c formed symmetrically in a direction perpendicular to the axial direction, and the inner side is fixed to the inner cylinder 3. It has a fan shape. The length of the elastic member 2 in the axial direction is equal to the length of the intermediate portion 1c, and is formed to be approximately two-fifths of the length of the outer cylinder 4 so as to be in close contact with the end portions 1a and 1b. The rubber bush 1 is made of a material that is more elastically harder than the rubber bush 1. Furthermore, as shown in FIG. 4, a vibration absorber 5 fixed to the outer cylinder 4 is placed in a part of the remaining space between the outer cylinder 4 and the inner cylinder 3 without coming into close contact with the rubber bush 1. ing. The vibration absorber 5 is fixed to both the outer cylinder 4 and the inner cylinder 3, and has a fan shape symmetrical with respect to a center line N perpendicular to the axial direction, and has a through hole 6 inside. is formed.

The function of the bush M will be explained by placing the bush M having the above-mentioned structure inside the cylindrical portion 70 of the L-shaped suspension arm S on the right front wheel side shown in FIG. 6 as an example. Note that the bush M is placed so that the end 1a side of the rubber bush 1 is at the front of the vehicle, and the vibration absorber 5 is at the vehicle body (not shown) side. First, in FIG. 6, when the automobile turns left while traveling straight ahead, a force is applied to the wheel coupling portion j in the direction of arrow A (toward the vehicle body side), and the force is transferred to the cylindrical portion. 70 and 80 are input. The force (load) input to the cylindrical portion 70 is further transformed into a force in two directions: a force compressing toward the vehicle body and a force compressing toward the front of the vehicle due to the influence of a moment with the cylindrical portion 80 as a fulcrum. Decomposed. First, the compressive force toward the vehicle body is shown in Figure 2.
In FIGS. 4 and 5, the force is directed downward from above and presses the outer cylinder 4 of the bushing downward in the figures. Due to this pressing force, the upper portion of the outer cylinder 4 in the figure moves toward the lower inner cylinder 3 while compressing each portion 1a, 1c, and 1b of the rubber bush 1. At this time, the rubber bush 1 sandwiched between the outer cylinder 4 and the inner cylinder 3 is compressed above the outer cylinder 4 and the inner cylinder 3, which are placed evenly between the outer cylinder 4 and the inner cylinder 3 (see Figures 2 and 4). As it is subjected to forces, the bushing M exhibits elasticity that provides great resistance. On the other hand, the force that compresses the vehicle forward side is input in the axial direction in FIG. 3, and becomes a force that displaces the outer cylinder 4 of the bush M upward in the figure. Due to this displacing force, the outer cylinder 4
While elastically deforming the end portion 1b (second large bushing) fixed to the lower part of the outer cylinder 4 in the figure and the vibration absorber 5, the inner cylinder 3
The elastic member 2 fixed to is compressed. Therefore, the bush M exhibits elasticity that provides a large resistance to the input when the bush M is compressed toward the vehicle body when turning.

Next, in FIG. 6, when the brake is activated while the vehicle is moving forward, the wheel coupling portion j is marked with an arrow B.
When a force is applied in the direction (vehicle longitudinal direction), the force is input to the cylindrical parts 70 and 80. This cylindrical part 7
The force (load) input to 0 is a force compressing toward the wheel joint j side (in the opposite direction to the vehicle body side) and a force compressing toward the rear side of the vehicle due to the influence of the moment with the cylindrical portion 80 as a fulcrum. It is decomposed into forces in two directions. First, the force compressing toward the wheel coupling part j is inputted from below to above (in a direction perpendicular to the axial direction) the outer cylinder 4 of the bush M in FIGS. 2, 4, and 5, and This is the force that pushes 4 upward in the figure. Due to this pressing force, the lower part of the outer cylinder 4 in the figure is
The vibration absorber 5 is moved upward toward the inner cylinder 3 while being compressed. At this time, the vibration absorber 5, which is sandwiched between the lower part of the outer cylinder 4 in the figure and the inner cylinder 3 and is subjected to compression, has an elastic constant at the opposite position via the inner cylinder 3 due to the hole 6 formed inside the vibration absorber 5. smaller than the elastic constant of rubber bush 1 placed in the bush M
is set to exhibit elasticity that provides small resistance to input (load). On the other hand, the force that compresses the vehicle toward the rear side is inputted from above to below in FIG. 3, and becomes a force that displaces the outer cylinder 4 of the bush M downward (in the axial direction) in the figure. This displacing force causes the outer cylinder 4 to elastically deform the end portion 1a (first rubber bushing) fixed to the upper part of the outer cylinder 4 in the figure and the vibration absorber 5, while the elastic member fixed to the inner cylinder 3 Compress 2. Note that the end portion 1a has an elliptical hole 2.
0a and 20a are formed, the elastic constant is smaller than that of the end 1b, and the bush M exhibits an elastic force that similarly provides small resistance to input when compressed toward the wheel coupling portion j. . That is, with the above configuration, the rubber bush 1 has an end portion 1a having a different elastic constant due to the elastic member 2.
, 1b, the elastic constant of the rubber bush 1 in the axial direction (vehicle longitudinal direction) differs depending on the direction of force input. Therefore, during braking, the elastic constants of the rubber bush 1 in the vehicle longitudinal direction and the vehicle body side direction with respect to the force (load) input to the wheel coupling portion j are set smaller than the elastic constants in each direction during turning. Ru. Therefore, depending on the settings of the arm length, rigidity, etc. of the suspension arm S, the force input to the wheel coupling portion j is transferred to the cylindrical portion 70.
Regardless of the ratio of separation between the longitudinal direction and the side direction of the vehicle, it is possible to set a large elastic constant during turning and a small elastic constant during braking.

In this embodiment, by forming the elliptical hole 20a in the end portion 1a, the elastic constants of the first rubber bushing 1a, which are the elements of the divided rubber bushing, can be adjusted in opposite directions in the axial direction. Although the elastic constant of the second rubber bush 1b is set to be smaller than that of the second rubber bush 1b, for example, the position where the elastic member 2 is fixed to the inner cylinder 3 may be shifted in the axial direction, and the elastic constant of the end portion 1a and 1b may be set to have an asymmetrical shape. In addition, in this example, the axes L of the outer cylinder 4 and the inner cylinder 3 are aligned, and the inner cylinder 3 is placed inside the outer cylinder 4 so that it is parallel to the outer cylinder 4. Without being limited to this example, for example, the inner cylinder 3 may be eccentrically set in advance to be parallel to the outer cylinder 4 depending on the weight (mass body) of each vehicle. As another means of using the bush M of this embodiment in the L-type suspension arm S, the bush M having the configuration used in this embodiment is rotated by 180 degrees around the axis L, i.e., the bush shown in FIG. The end 1a of the upper rubber bush 1 faces toward the rear of the vehicle, and the vibration absorber 5 in FIG. 4 is attached to the vehicle body (not shown).
A bush facing in the opposite direction may be installed in the cylindrical portion 80. Further, as another means of using the bush M of this embodiment, for example, the bush M may be installed in a vehicle equipped with a semi-trailing arm, and the bush M may be used when turning left or right.
By varying the elastic support of the wheels, alignment changes during left and right turns may be varied.

[0011]

According to the present invention, the elastic constant of the bush in one direction is greater than the elastic constant in the opposite direction in two directions: the axial direction and the direction perpendicular to the axial direction. Since it is set small, the elastic constant that resists the direction of the load can be changed depending on the direction of the load acting on the bush, so the displacement of the mass supported by the bush can be adjusted with high precision.

[Brief explanation of the drawing]

[Figure 1] External view of bush M of the present invention

[Figure 2]
Plan view of Figure 1 viewed from above

[Figure 3] A in Figure 2
A cross-sectional view of point A

[Figure 4] A cross-sectional view of the B-B location in Figure 1

[Figure 5] A cross-sectional view of the C-C location shown in Figure 2

FIG. 6 shows an L-shaped suspension arm S.

FIG. 7 shows a prior art bushing.

[Explanation of symbols]

M: Bush 1: Rubber bush 1a: Shaft end (first rubber bush) 1b: Shaft end (second rubber bush) 1c: middle part, 2: Elastic member 5: Vibration absorber 3: Inner cylinder 4: Outer cylinder 6: Through hole 20a: Oval hole L: Axis line N: Center line

Claims (1)

[Claims] 1. An outer cylinder made of a hollow cylindrical rigid material, and a hollow cylindrical rigid material placed inside the outer cylinder so as to be parallel to the outer cylinder. A bushing having a rubber bush that switches an elastic constant depending on a change in the direction of a load along a direction perpendicular to an axial direction between the inner cylinder and the inner cylinder, , an elastic member is fixed, and on one end side of the elastic member in the axial direction, a first rubber bush fixed to the side of the inner cylinder or the outer cylinder to which the elastic member is not fixed; On the other end side of the elastic member in the axial direction, there is a second tube fixed to the side to which the elastic member is not fixed, of the inner tube or the outer tube.
A bushing characterized in that a rubber bush is disposed, and the elastic constant of the first rubber bush is set smaller in the axial direction than the elastic constant of the second rubber bush.