JPH08284993A - Bush assembly - Google Patents

Abstract

PURPOSE: To independently set the respective spring constants in the axial direction of a cylinder, the longitudinal direction, and the right-to-left direction by using an inner cylindrical body provided with a barrier part and an extension part. CONSTITUTION: Extension parts 12 are respectively projected from each side in the Z-direction of the axis of a body cylindrical part 11 and to each side in Y-direction, and a rubber elastic body part 3 to be held between a pair of the extension parts 12 is dead for the external force in the Z-direction of the cylinder axis, and the spring constant in the Z-direction of the cylinder axis can be increased thereby. The external force in the X-direction is shared also by the rubber elastic body part 3, and the spring constant in the X-direction can be reduced thereby. The spring constant in the X-direction which is apt to be harder than that in the Z-direction of the cylinder axis when the end part of the rubber elastic body 3 is joined with the inner circumferential surface of an outer cylindrical body 2 can be coincided with or brought close to the spring constant in the Z-direction of the cylinder axis by increasing the spring constant in the Z-direction and reducing the spring constant in the X-direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bush assembly used in the field of automobiles, for example, for interposing parts for elastically supporting them on a vehicle body.

[0002]

2. Description of the Related Art Conventionally, as a bush assembly of this type, generally, a large and small cylindrical outer cylinder and an inner cylinder are arranged coaxially, and both cylinders are orthogonal to the cylinder axis of the inner cylinder. It is known that rubber elastic members are connected in one direction.
Then, other members are fixed to the outer periphery of the cylindrical inner cylindrical body so that the outer peripheral shape in the cross-sectional shape becomes a quadrangle and a part of the inner peripheral surface of the cylindrical outer cylindrical body is formed. A thick portion is provided on the inner surface of the rubber elastic body so that the joint surfaces of the rubber elastic body on the inner cylinder side and the outer cylinder side are not arcuate surfaces but flat surfaces (for example, see JP-A-2-93134). Alternatively, a square tube is externally fitted and fixed to the cylindrical inner cylinder body, a rubber elastic body is connected to one flat surface of the square cylinder, and an intermediate plate having a plane parallel to the flat surface is connected to the square cylinder and the cylindrical outer surface. What is interposed in the rubber elastic body between the cylinder (for example,
Japanese Utility Model Laid-Open No. 56-45635) is known.

[0003]

By the way, in the bush assembly, the large and small cylindrical outer cylinders and the inner cylinder are arranged coaxially, and both cylinders are arranged in the first direction orthogonal to the cylinder axis of the inner cylinder. Using the ones connected by the stretched rubber elastic body, for example, in order to achieve both steering stability of the automobile and anti-vibration support of parts, in the axial direction of the inner cylinder (for example, the vertical direction of the vehicle body),
Elastic support is possible in a three-dimensional direction including the first direction (for example, the left-right direction of the vehicle body) and a second direction (for example, the front-back direction of the vehicle body) that is orthogonal to both the cylinder axis direction and the first direction, and There is a demand for individually and independently setting each spring constant in the three-dimensional direction.

For example, in a so-called FR vehicle of a front engine / rear drive, in order to mount a subframe of a rear suspension on a vehicle body, a direction in which a rubber elastic body extends in the cylinder axis direction of a bush assembly in a vertical direction (the above-mentioned first (1 direction) is used in the left-right direction of the vehicle body,
The bush assembly is provided with anti-vibration spring constants in the cylinder axis direction and in the front-rear direction of the vehicle body (second direction described above), that is, in the direction in which the force acts as a shearing force on the rubber elastic body. Both must be soft in terms of performance.
On the other hand, the spring constant in the above left-right direction, that is, the direction in which the force acts on the rubber elastic body as a compression / tensile force,
It is necessary to make it hard to some extent in terms of steering stability of the car.

However, regarding the spring constant in the cylinder axis direction, since the sub-frame must be supported by the spring in the cylinder axis direction based on the rubber elastic body, the spring constant in the cylinder axis direction is soft. There is a limit to what you can do. That is, a differential gear is mounted on the sub-frame, and the torque acts on the sub-frame during acceleration to cause the sub-frame to fall down. It is necessary to make the spring constant in the direction harder than a certain fixed value, and there is a requirement that conflicts with the above-mentioned required performance.

Further, regarding the mutual relationship in the two spring constants in the two directions of shearing of the cylinder axis direction and the longitudinal direction, one end of the rubber elastic body is joined to the inner peripheral surface of the cylindrical outer cylinder body. Since the length of the rubber elastic body portion that resists shear force in each of the cylinder axis and the front-rear direction is different from each other due to the existence of the circular arc portion on the outer cylinder side, the front-back direction spring constant is the same as that of the cylinder axis direction. It is generally harder than that. In this respect, in the above-mentioned conventional technology, in the case where a flat surface is provided by providing a thick portion on the inner peripheral surface of the outer cylindrical body, the influence of the above-mentioned arc portion disappears, and although the two spring constants in the two shear directions match, In addition to increasing the number of steps for forming the thick portion in the tubular body, setting the outer tubular body at the time of integral vulcanization molding of the rubber elastic body also takes time.

Therefore, regarding the relationship between the cylinder axial direction spring constant and the front-back direction spring constant for the two shear directions,
Even if the spring constant in the cylinder axis direction is suppressed to a certain value that does not become too soft, and the cylindrical outer cylinder body is used as it is without forming the thick portion, the spring constant in the cylinder axis direction is lower than that in the cylinder axis direction. There is a demand for the development of a bushing assembly capable of matching the spring constant in the front-rear direction, which tends to be stiff, with the spring constant in the cylinder axial direction or making it as close as possible.

Further, it is difficult to make the spring constant in the left-right direction relatively hard while having the target performances for both the spring constant in the cylinder axis direction and the front-back direction. It becomes softer than the required performance for the spring constant. That is, in order to make the left-right spring constant hard, the shape must be set so as to further increase the cross-sectional area of the rubber elastic body that receives a compressive force from the left-right direction. But,
Then, the above-mentioned spring constants in the shearing direction in both the cylinder axis direction and the front-rear direction change, and it becomes impossible to satisfy the requirements for the target performance for them. In this respect, it is possible to adopt a measure for increasing the spring constant in the left-right direction by interposing the intermediate plate in the above-mentioned conventional technique,
In addition to increasing the number of steps for interposing the intermediate plate, the presence of the intermediate plate also changes the spring constants in the cylinder axis direction and the front-rear direction.

The present invention has been made in view of the above circumstances, and an object thereof is to make it possible to set spring constants in the cylinder axis direction, the front-rear direction, and the left-right direction independently of each other, and , To facilitate setting of required performance. This makes the spring constant in the left-right direction relatively hard, and even if the cylindrical outer cylinder is used as it is, the spring constant in the cylinder axial direction and the spring constant in the front-rear direction are equal to each other or as much as possible. By approaching them, it is necessary to satisfy both requirements for steering stability and requirements for elastic support performance and anti-vibration performance.

[0010]

In order to achieve the above object, the invention according to claim 1 is an inner cylinder body and an outer cylinder body which surrounds the inner cylinder body in parallel to the cylinder axis of the inner cylinder body. It is assumed that a rubber elastic body is provided that extends from the inner cylinder to both sides in the first direction orthogonal to the cylinder axis and connects the outer surface of the inner cylinder and the inner surface of the outer cylinder to each other. In this structure, the inner tubular body is provided with the main body tubular portion into which the mounting shaft body is inserted, and the inner tubular body is provided on both sides of the main body tubular portion in a second direction orthogonal to both the tubular axial direction and the first direction. A pair of barrier portions projecting into the rubber elastic body and interposed in the rubber elastic body, and both sides on the cylinder axial direction of the main body cylindrical portion that are separated from each other in the cylinder axial direction forming range of the rubber elastic body. Between a pair of overhanging portions projecting into the rubber elastic body on both sides in the first direction from positions, and between the cylinder axial direction opposing surfaces of the pair of overhanging portions on both sides in the first direction with the main body tubular portion sandwiched therebetween. And a pair of concave groove portions in which the rubber elastic body is arranged.

According to a second aspect of the present invention, in the first aspect of the invention, the barrier portion of the inner cylindrical body projects over the entire width of the rubber elastic body in the second direction.

According to a third aspect of the present invention, in the first aspect of the present invention, the overhanging portions on both sides of the inner cylindrical body in the cylinder axis direction are formed in a range over the entire width of the rubber elastic body in the second direction. .

According to a fourth aspect of the present invention, in the invention according to the first aspect, the overhanging portions on both sides in the cylinder axis direction of the inner cylinder are provided over the same second direction range as the forming range of the barrier section in the second direction. It is formed so that the shape viewed from the cylinder axis direction is a substantially quadrangle.

According to a fifth aspect of the invention, in the invention of the first aspect, the wall thickness of the inner cylindrical body in the first direction is set within a range of the width of the main body cylindrical section in the first direction. Is.

According to a sixth aspect of the present invention, in the first aspect of the invention, the barrier portion of the inner tubular body is integrally connected to the respective overhanging portions on both sides in the tubular axial direction.

According to a seventh aspect of the present invention, in the first aspect of the present invention, as the inner tubular body, the main body tubular portion, the overhanging portions on both sides in the tubular axial direction, and the barrier portion are integrally formed of the same material. And then configure.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the inner cylindrical body includes the main body cylindrical portion in which the overhanging portions on both sides in the cylinder axial direction and the barrier portion are the main body cylindrical portion. And are integrally formed of different materials.

Further, the invention of claim 9 is the same as claim 1.
In the invention described above, the outer cylinder is formed into a cylindrical shape.

[0019]

According to the above-mentioned structure, according to the first aspect of the present invention,
Since the projecting portions project from both sides of the main body tubular portion in the tubular axial direction to both sides in the first direction, when an external force in the tubular axial direction is input to the inner tubular body or the outer tubular body, a space between the pair of overhanging portions is provided. The rubber elastic body portion sandwiched between the above does not function as a resistance element against the above external force, so-called dead rubber, and the rubber elastic body portion in the range from the overhanging end of the overhanging portion to the inner peripheral surface of the outer cylindrical body is exposed to the above external force. You will effectively resist.
Therefore, as compared with the case where the rubber elastic body in the range from the main body cylindrical portion to the inner peripheral surface of the outer cylindrical body resists the external force in the cylinder axial direction, the first direction length of the rubber elastic body resists the external force in the cylinder axial direction. Is shortened by the overhang length of the overhang portion, and accordingly the spring constant in the cylinder axis direction becomes hard. Therefore, the larger the overhang length of the overhang portion, the harder the axial constant in the cylinder axis direction can be made.

On the other hand, when an external force from the second direction is applied to the inner cylinder body or the outer cylinder body, the rubber elastic body portion existing between the pair of overhang portions on both sides in the cylinder axis direction is also the second rubber body. In order to effectively resist the external force in the direction, the rubber elastic body in the range from the main body cylindrical portion to the vicinity of the inner peripheral surface of the outer cylindrical body resists the external force in the second direction. Therefore, the spring constant in the second direction is softer than in the case where the rubber elastic body portion between the overhanging portions is dead and becomes rubber. As a result, even if the end portion of the rubber elastic body is joined to the circumferential surface of the inner peripheral surface of the outer cylindrical body, the second elastic member tends to be harder than the cylindrical axial direction spring constant.
The directional spring constant can be made equal to or close to the cylinder axis direction spring constant by making the cylinder axis direction spring constant hard and the second direction spring constant soft.

In addition, the inner cylinder or the outer cylinder has a first structure.
When an external force is applied from the direction, the barrier portion is formed so as to project from the main body tubular portion to both sides in the second direction, and the first barrier portion of the barrier portion is formed.
The length in the first direction in which the rubber elastic body resists the external force in the first direction and is compressed is reduced by the amount corresponding to the thickness in the first direction.
The spring constant in the first direction becomes hard. Therefore, as the thickness of the barrier portion in the first direction increases, the first
The directional spring constant can be made harder, and even if the thickness of the barrier portion in the first direction is changed, the rubber elastic body portion that resists external force from the cylinder axis direction and the second direction can be obtained. Since there is almost no influence, it is possible to change and set the first direction spring constant independently of both the spring constants in the cylinder axis direction and the second direction.

As described above, by using the inner cylindrical body having the barrier portion and the overhanging portion as in the present invention, the second axial direction is improved.
Direction, and three spring constants for each direction of the first direction can be set independently of each other, and the first direction spring constant can be made relatively hard, and the cylinder axis direction and the second direction can be set.
It is possible to set both spring constants in the directions so as to match or approximate each other.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, since the barrier portion of the inner cylindrical body projects over the entire width in the second direction of the rubber elastic body, The directional spring constant can be increased more efficiently and effectively.

According to the third aspect of the present invention, in addition to the function of the first aspect of the present invention, since each of the overhanging portions of the inner cylindrical body is formed over the entire width in the second direction of the rubber elastic body, An increase in the axial spring constant and a decrease in the second spring constant can be achieved more efficiently and effectively.

According to the invention described in claim 4, in addition to the operation according to the invention described in claim 1, each of the overhanging portions of the inner cylinder is provided over the second direction range which is the same as the forming range of the barrier part, and the cylinder axial direction Since the shape seen from above is formed into a substantially quadrangular shape, the end face of the rubber portion becomes a flat surface extending in the second direction due to the external force in the cylinder axial direction, and the spring constant in the cylinder axial direction is increased,
The reduction of the second direction spring constant is efficiently performed.

According to the fifth aspect of the present invention, in addition to the effect of the first aspect of the invention, the wall thickness of the barrier portion of the inner cylinder in the first direction is set within the range of the width of the main body cylinder in the first direction. Therefore, the first-direction spring constant is increased within a range that does not affect the second-direction spring constant.

According to the sixth aspect of the invention, in addition to the effect of the first aspect of the invention, since the barrier portion of the inner cylinder is integrally connected to the overhanging portions on both sides in the cylinder axis direction, the cylinder The above-mentioned barrier portion and each overhanging portion that divides, forms or switches the rubber elastic body portion that expresses each spring constant in the axial direction, the second direction and the first direction surely act, respectively, and thereby each rubber elastic body As a result, the spring constants in the respective directions can be reliably exerted at predetermined values.

According to the invention described in claim 7, in addition to the operation according to the invention described in claim 1, the inner cylinder body comprises a main body cylinder part,
Since each overhanging portion and the barrier portion are integrally formed of the same material, the structural strength of the inner cylindrical body is increased, and
The formation process is rationalized.

Further, in the invention described in claim 8, in addition to the operation according to the invention described in claim 1,
Since each of the overhanging portions and the barrier portion are integrally formed of the inner tubular body made of a material different from that of the main body tubular portion, the inner tubular body having a desired shape according to the change in the size of each overhanging portion or the barrier portion. Mass production can be easily performed.

Further, according to the invention of claim 9, even if the outer cylindrical body is used as it is and the end portion of the rubber elastic body is joined to the inner peripheral surface which is the circumferential surface of the outer cylindrical body, The rubber elastic body portion between the two overhanging portions on both sides in the axial direction deadly becomes rubber against the external force in the axial direction of the cylinder, and becomes an effective resistance element against the external force in the second axial direction, thereby increasing the spring constant in the axial direction of the cylinder. And the reduction of the spring constant in the second direction, the operation according to the invention of claim 1 is surely obtained, and the trouble of forming a thick portion on the inner peripheral surface of the cylindrical outer cylindrical body as in the conventional case. It is possible to omit special processing.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a bush assembly according to an embodiment of the present invention, in which 1 is an inner cylinder, and 2 is coaxial with the cylinder axis Z of the inner cylinder 1 so as to surround the inner cylinder 1. The arranged cylindrical outer cylinders 3 extend from the inner cylinder 1 to both sides in the Y direction, which is a first direction orthogonal to the cylinder axis Z, and extend between the inner cylinder 1 and the outer cylinder 2. Is a rubber elastic body for connecting the.

As shown in detail in FIG. 4, the inner cylindrical body 1 has a cylindrical main body cylindrical portion 1 arranged along the cylindrical axis Z.
1 and both side positions of the main body cylinder portion 11 in the cylinder axis Z direction (vertical direction in FIGS. 2 and 4) and both ends of the range in which the rubber elastic body 3 is formed on the inner cylinder body 1 in the cylinder axis Z direction. A pair of overhanging portions 12 and 12 extending from the periphery of the position in a direction orthogonal to the tube axis Z, and the tube so as to connect the pair of overhanging sections 12 and 12 from the body tube portion 11 to each other. And a pair of barrier portions 13 projecting to both sides in the X direction, which is the second direction orthogonal to both the Z and Y directions, and these 11, 12, 12, 13, 13 are made of the same metal material. It is integrally formed by using. For example, it may be formed of sintered metal, or the protruding portions 12 and the barrier portions 13 may be separately formed by lathe processing and welded to the main body tubular portion 11.

A subframe mounting shaft (not shown) of a rear suspension, for example, is inserted as a mounting shaft into the through hole 14 penetrating along the cylinder axis Z of the main body cylindrical portion 11 and connected to the inner cylindrical body 1. It is supposed to be done.

Each of the overhanging portions 12 is formed so as to project from the main body tubular portion 11 by a predetermined amount in the Y direction and the X direction, and has a substantially quadrangular shape when viewed from the tubular axis Z direction. In addition, the X-direction end surface of each of the overhanging portions 12 is provided with each of the barrier portions 1
3 and the same plane. That is,
Each of the overhanging portions 12 has an X-direction dimension F overhanging in the X-direction across the main-body tubular portion 11 over the same range as the X-direction forming range of each of the barrier portions 13, and a tube in the Y-direction. Axis Z
The overhanging dimension W is determined according to the target setting values of the spring constants in the X direction and the X direction. The dimension F in the X direction is
It is set within the range of the width of the rubber elastic body 3 in the X direction, and preferably set to be equal to the width of the rubber elastic body 3 in the X direction.
Further, the wall thickness t of each of the barrier portions 13 in the Y direction is determined according to the target set value of the spring constant of the rubber elastic body (hereinafter, referred to as the Y direction spring constant) with respect to the Y direction input. It is preferable to set the width within the range equal to or smaller than the width of the main body tubular portion 11 in the Y direction, that is, the outer diameter d thereof.

The inner tubular body 1 includes the respective barrier portions 13 extending in the tubular axis Z direction, the main body tubular portion 11, and the main body tubular portion 1.
1 and a pair of overhanging portions 12 and 12 extending in the Y direction, which are formed in a V shape when viewed from the Y direction, and between the pair of overhanging portions 12 and 12 extending in the X direction. 1
5 are formed on both sides in the Y direction with the body tube portion 11 interposed therebetween. The overall dimension L between the outer ends of the pair of overhang portions 12, 12 in the cylinder axis Z direction, that is, the pair of overhang portions 12, 12.
The overall dimension L in the cylinder axis Z direction of the portion where 12 and the pair of barrier portions 13 and 13 are formed is equal to the above-mentioned pair of overhang portions 12 and 12.
As described above, since the rubber elastic body 3 is provided at both outer end positions of the rubber elastic body 3 in the cylinder axis Z direction at the position of the inner cylinder body 1, the width of the rubber elastic body 3 is substantially equal to the Z axis direction. In addition, the distance L1 between the pair of overhanging portions 12, 12 facing each other in the cylinder axis Z direction.
That is, the groove width L1 of the concave groove portion 15 in the cylinder axis Z direction is
The relationship between the spring constant of the rubber elastic body 3 with respect to the cylinder axis Z direction input (hereinafter referred to as the cylinder axis Z direction spring constant) and the spring constant of the rubber elastic body 3 with respect to the X direction input (hereinafter referred to as the X direction spring constant) is shown. It is decided based on how to decide.

The rubber elastic body 3 is the X of the inner cylindrical body 1.
The width in the directional direction, that is, the width in the X direction of the pair of overhanging portions 12 and 12 and the pair of barrier portions 13 and 13 is set to be substantially equal to each other, and is substantially straight from the inner cylindrical body 1 to both sides in the Y direction. It extends and is joined to the inner peripheral surface of the outer cylindrical body 2. Further, reference numerals 31 and 31 in FIG. 1 and FIG. 2 denote stopper portions formed at inner peripheral surface positions of the outer cylindrical body 2 facing the inner cylindrical body 1 in the X direction. Such a rubber elastic body 3 and each stopper portion 31 are formed by integral vulcanization molding using the inner cylindrical body 1 and the outer cylindrical body 2 as insert materials.
The rubber elastic body 3 and the stopper portion 31 are vulcanized and bonded to the outer surface of the inner cylindrical body 1 and the inner peripheral surface of the outer cylindrical body 2.

2 and 3, reference numeral 21 denotes a flange portion in which one end side of the outer cylindrical body 2 in the cylinder axis Z direction is widened in the outer peripheral direction.
Reference numerals 32, 32, ... Denote stopper pieces protruding outward from the flange portion 21 in the cylinder axis Z direction.

In the bush assembly having the above construction, when the rear suspension subframe is used for mounting on the vehicle body, for example, the stopper pieces 32, 3 are used.
2, ... are set to the upper side and the cylinder axis Z direction is arranged in the vertical direction, and Y
The direction is arranged in the left-right direction (width direction) of the vehicle body, and the X direction is arranged in the front-rear direction of the vehicle body. Then, the mounting shaft of the sub-frame is inserted into the through hole 14 and the inner cylindrical body 1
On the other hand, the outer cylindrical body 2 is connected to the vehicle body side via a bracket or the like.

In this case, with respect to the external force from the cylinder axis Z direction, as shown in FIGS. 5 and 6, the cylinder axis Z of the rubber elastic body 3 is used.
The rubber elastic body portions 33, 33 in the both recessed grooves 15, 15 sandwiched by the pair of overhanging portions 12, 12 at both ends in the direction are relatively displaced integrally with the inner cylindrical body 1 to serve as a resistance element against the external force. It becomes a rubber part to death that does not become. Therefore, with respect to the external force in the cylinder axis Z direction, the rubber elastic body portions 3 are
The rubber elastic body parts 34, 34 excluding 3 effectively resist,
The spring constant of the cylinder axis Z direction is determined based on the rubber elastic body portions 34, 34. Therefore, compared with the case where the entire rubber elastic body 3 from the outer peripheral surface of the main body cylindrical portion 11 to the inner peripheral surface of the outer cylindrical body 2 serves as a resistance element, the rubber portion (3
3, 33), the length Sz that receives the shearing force by the external force in the cylinder axis Z direction is shortened, and the spring constant in the cylinder axis Z direction is correspondingly increased, that is, the length becomes rigid.

On the other hand, with respect to the external force from the X direction (front-back direction of the vehicle body), as shown in FIG. 7, the inner peripheral surface side of the outer cylindrical body 2 which is not continuous in the X direction of the rubber elastic body 3. Although the arcuate portions 35, 35 of FIG. 3 do not become effective resistance elements, the rubber elastic body 3 including the rubber elastic body portions 33, 33 in the above-mentioned both concave grooves 15, 15 is excluded except the arcuate portions 35, 35. Almost the entire portion 36, 36 of this will effectively resist. That is, as compared with the case where the external force in the cylinder axis Z direction is applied, the arcuate portions 35, 35 are removed, but instead, the rubber elastic body portions 33, 33 in the recessed grooves 15 are added as resistance elements. Become. Therefore, the length Sx that receives the shearing force due to the external force in the X direction becomes longer than that in the case where the rubber elastic body portion 34 receives the external force in the Z direction in the cylinder axis, and the spring constant in the X direction is relatively corresponding to this. It is reduced, that is, soft.

As a result, even if both ends of the rubber elastic body 3 in the Y direction are directly joined to the inner peripheral surface of the outer cylindrical body 2, that is, the circumferential surface, and the joint portions are arcuate, they are in the X direction. The spring constant can be brought close to or match the spring constant in the cylinder axis Z direction. That is, due to the existence of the arcuate portions 35 and 3 which are the joint portions of the rubber elastic body 3 to the outer cylindrical body 2, the X direction spring constant is conventionally larger (harder) than the cylinder axis Z direction spring constant. You can eliminate the tendency to become. As a result, the cylindrical outer cylinder can be used as it is, and the step of forming a thick portion on the inner peripheral surface of the outer cylinder to form the flat surface can be omitted. And the above-mentioned two directions of shear X
The relative relationship between the directional spring constant and the cylinder axis Z-direction spring constant is determined by the size of the rubber elastic body portion 33 that dies or becomes a resistance element depending on the input direction of the external force, that is, the pair of overhanging portions 12. , 12 can be easily adjusted by changing the distance L1 between the facing surfaces.

Further, with respect to an external force from the Y direction, the barrier portions 13, 13 are embedded in the rubber elastic body 3 so as to traverse a range of almost the entire width in the X direction orthogonal to the Y direction from the main body tubular portion 11. Therefore, the length in the Y direction in which the rubber elastic body 3 is compressed based on the external force in the Y direction is shortened by the thickness t of the barrier portions 13 in the Y direction, which makes the Y direction spring constant hard. Become. Therefore, the larger the Y-direction thickness t of the barrier portion, the harder the Y-direction spring constant can be made. Even if the Y-direction thickness t of each barrier portion 13 is changed, the change can be made. The relevant portions are the respective rubber elastic body portions 33 that die to become a rubber against the external force in the Z-direction of the cylinder axis, and have almost no influence on the rubber elastic body portion 36 that resists the external force in the X-direction external force. Since there is no portion, the spring constant in the Y direction can be set and adjusted independently of the spring constants in the Z direction and the X direction, which are the two shear directions, and the change setting can also be made. This can be easily performed only by changing the wall thickness of each barrier portion 13 (width t in the Y direction).

As described above, according to this bush assembly,
Desired spring constants can be exerted against external forces in the three-dimensional directions of the cylinder axis Z direction, the X direction, and the Y direction, and the cylinder axis Z direction spring constant, X direction spring constant, and Each of the Y-direction spring constants can be set independently of each other, depending on the target performance required at the mount site to which the present bush assembly is applied,
Moreover, the setting adjustment can be easily performed. For this reason, when the rear suspension sub-frame is applied to the mounting portion of the vehicle body, the X-direction spring constant is increased to such an extent that it does not become too hard as described above, and the X-direction spring constant is increased. The spring constant of the Y-direction should be close to or the same as that of the directional spring to secure the supporting rigidity of the sub-frame while satisfying the vibration isolation performance in the two directions of shear. It can be set and adjusted to be hard independently of the spring constant of, and the required performance from steering stability can also be satisfied.

<Analysis Result> Next, the analysis result of the bush assembly of the present invention analyzed by the finite element method will be described.

[Effect of Dimensions of Each Part on Each Spring Constant] FIGS. 8 to 10 show the cylinder axis Z-direction spring constant Kz and the X-direction spring constant Kx when the size of each part of the inner cylinder 1 is variously changed.
, And the effect on the Y-direction spring constant KY.

-Influence of the facing surface spacing L1-First, FIG. 8 shows the concave groove 1 formed by the pair of overhanging portions 12,12.
5 shows the influence of the existence of the grooves 5, 15 and the size of the respective concave grooves 15 on the above-mentioned three-dimensional spring constants Kz, Kx, KY. In this analysis, the overall dimensions L (see FIG. 4) of the pair of overhanging portions 12, 12 are fixed values,
The respective spring constants Kz, Kx, and KY were obtained when only the distance L1 between the facing surfaces was changed.

As a fixed value, the overall dimension L is 40 m
m, overhang dimension W is 40 mm, outer diameter d of the main body cylinder is 30
mm, and the wall thickness t of the barrier 13 was set to 20 mm. Then, the above-mentioned face-to-face spacing L1 was changed in the range of 0 to 30 mm. FIG. 8 shows the spring constants Kz, Kx, and
The change in KY is shown with the actual value of the facing surface spacing L1 and the ratio (L1 / L) of L1 to the overall dimension L as the horizontal axis.

As a result, in the case of L1 = 0 (L1 / L = 0), that is, when the inner cylindrical body in which the concave groove 15 does not exist and the outer surface is substantially prismatic is used, the spring constant in the X direction is used. Kx is considerably larger than the spring constant Kz in the Z-axis direction of the cylinder axis, and therefore becomes considerably hard. On the other hand, when the concave groove 15 is provided, its groove width (interval between facing surfaces L1) becomes large. As described above, the spring constant Kx in the X direction becomes equal to the spring constant Kz in the cylinder axis Z direction.
Tends to approach. Further, here, even if the groove width L1 is changed to a large value, the value itself of the cylinder axis Z-direction spring constant Kz hardly changes as compared with the case where the concave groove 15 does not exist (when L1 = 0), It is shown that the rubber elastic body portion 33 in the concave groove 15 is dead rubber against the external force in the cylinder axis Z direction.

On the other hand, the Y-direction spring constant Ky decreases from the case where the concave groove 15 does not exist (when L1 = 0) and decreases as the groove width L1 is set to a large value. . With respect to the external force in the Y direction, when L1 = 0, the compression length of the rubber elastic body is shortened in the entire cross section of the rubber elastic body by the inner cylinder of the substantially prismatic shape, and the spring constant Ky in the Y direction is large. On the other hand, when the groove 15 is provided and the groove width L1 is increased, the cross-sectional portion where the compression length is shortened is reduced by the groove 15, and as a result, the Y direction spring constant is increased. It is considered that Ky is reduced. That is, it is considered that the Y-direction end surface of each overhanging portion 12 is also involved in increasing the Y-direction spring constant Ky, which is the same as each barrier portion 13. Thus, in the Y direction spring constant Ky, the groove width L
As 1 increases, the spring constant K in other two directions of shear
It is preferable that the value be as large as possible from the standpoint of maneuvering stability while keeping the value larger than x and Kz while it is large, but it will cause deterioration of road noise, so it will be a little more value from the anti-vibration surface. Is consistent with the performance requirement of reducing

Incidentally, Kz1, Kz2, K in FIG.
x1, Kx2, Ky1, and Ky2 do not have the above-mentioned groove 15 (L1
/ L = 0) and a certain one (L1 / L = 0.7) were manufactured, and the measured values of the spring constants in the cylinder axis Z direction, X direction, and Y direction were plotted. is there. The dimensions of each part of this test body are L = 42, t = 15, W = 40, and the rubber hardness Hs of the rubber elastic body 3 is 60 °. The above measurement was conducted to confirm the effectiveness of the above analysis, and as a result, the above measured values are slightly different from those of the above analysis in the dimensions of each part of the assumption, but the same tendency as the analysis result. It was almost the same.

-Effect of Wall Thickness t of Barrier Section 13- FIG. 9 shows the effect of the thickness t of the barrier section 13 on the three-dimensional spring constants Kz, Kx, and KY. . In this analysis, as fixed values, the overall dimension L is 40 mm, the overhanging dimension W is 40 mm, and the outer diameter d of the main body tubular portion is
Is 30 mm, and the groove width L1 of the concave groove is 30 mm (L1 / L =
0.75), and the wall thickness t of the barrier 13 is set to 1
The spring constants Kz and K can be changed within the range of 0 to 20 mm.
The values of x and KY were obtained.

As a result, when the wall thickness t of the barrier portion 13 increases, the Y-direction spring constant Ky correspondingly increases and changes to a hard one, but the spring constant Kz and the X-direction spring constant Kx change. Without maintaining the same value. That is,
This indicates that if the wall thickness t of the barrier portion 13 is changed and adjusted, only the value of Ky can be tuned independently without changing the values of Kz and Kx. Therefore, the tuning of the spring constant Ky in the Y direction can be independently performed without changing the characteristic in the other direction by an easy means of changing the dimension of the wall thickness t of the barrier portion 13 without providing any special mechanism. You will be able to

-Effect of Overhang Dimension W of Overhang 12- FIG. 10 shows the effect of the overhang W of the overhang 12 on the above-mentioned three-dimensional spring constants Kz, Kx, KY. is there. In this analysis, as a fixed value, the overall dimension L is 40 mm and the groove width L1 of the concave groove is 30 mm (L1
/L=0.75), the outer diameter d of the main body cylindrical portion is set to 30 mm, the wall thickness t of the barrier portion 13 is set to 15 mm, and the overhanging dimension W is changed in the range of 35 to 42 mm to set each spring. The values of constants Kz, Kx and KY were obtained.

As a result, when the value of the overhanging dimension W increases, the three of Kz, Kx, and Ky correspondingly increase,
It increases and changes to a hard one. That is, if the value of the overhanging dimension W is increased, the spring constants Kz and Kx in the above three directions are increased.
, Ky can be hardened with the same tendency.

[Model Deformation] FIGS. 11 to 14 show
In this analysis model, the outer cylindrical body 2 is fixed, and the shape of the rubber elastic body 3 after deformation is shown when an external force is applied to the inner cylindrical body 1 in the cylinder axis Z, X, or Y direction. Is.

-Deformation due to external force in X direction-Fig. 11 shows the rubber elastic body portion in the groove 15 in the cross section taken along the line CC of Fig. 3, that is, the outer peripheral surface of the main body cylindrical portion 11 and the outer surface of each barrier portion 13. With respect to the rubber elastic body 3 sandwiched between the inner peripheral surface of the outer cylindrical body 2, the shape before deformation (the shape shown by the broken line) when an external force in the X direction is applied to the inner cylindrical body 1, and the shape after deformation. The shape (the shape indicated by the solid line) is shown. Further, FIG. 12 shows a shape before deformation of the overhanging portion 12 and the rubber elastic body 3 in a cross section taken along the line D-D in FIG. 3 when an external force in the X direction is applied to the inner cylindrical body 1 (a shape shown by a broken line). And the shape after deformation (the shape indicated by the solid line).

According to this, the rubber elastic body 3 in the concave groove 15 of FIG. 11 receives an external force in the X direction, and the rubber elastic body portion in the vicinity of the outer cylindrical body 2 (corresponding to the arc-shaped portion 35 of FIG. 7). Excluding the dimension y1 in the Y direction from the outer peripheral surface of the main body tubular portion 11 to the outer tubular body 2.
Almost the whole has undergone deformation. On the other hand, in the rubber elastic body 3 at the position of the overhanging portion 12 in FIG. 12, the dimension in the Y direction that is deformed by receiving the external force in the X direction becomes as short as the dimension y2 from the outer surface position of the overhanging portion 12 to the outer cylindrical body 2. . This FIG.
The case corresponds to the deformation of the rubber elastic body when the concave groove 15 does not exist at the cross-sectional position of FIG. 11 and the overhanging portion 12 is continuous in the cylinder axis Z direction. Therefore, in the case where the groove 15 is provided (in the case of FIG. 11), the rubber elastic body in a longer range is bent by the force in the shearing direction as compared with the case where the groove 15 is not provided (in the case of FIG. 12), and the X direction spring constant is Kx becomes softer.

-Deformation by external force in the cylinder axis Z direction-FIG. 13 shows an external force applied to the inner cylinder body 1 in the cylinder axis Z direction (external force upward in FIG. 13) with respect to the rubber elastic body 3 in the cross section of the lower half of FIG. The shape before deformation (the shape indicated by the broken line) and the shape after the deformation (the shape indicated by the solid line) are shown.

According to this, the rubber elastic body portion 33 (see FIG. 6) in the concave groove 15 is hardly deformed even when an external force is applied in the cylinder axis Z direction, and is deformed by the external force in the cylinder axis Z direction. Is fixed to the rubber elastic body portion 34 (see FIG. 6) excluding the rubber elastic body portion 33 described above. That is, the rubber elastic body portion 33 in the concave groove 15 surrounded by the upper and lower protruding portions 12, 12 becomes a rubber dead against the external force in the cylinder axis Z direction, and even if the concave groove 15 is actually present. This is the same as the case where the overhanging portion 12 is continuous in the cylinder axis Z direction and the concave groove 15 does not exist. Therefore, by forming each overhanging portion 12, it is possible to increase the spring constant with respect to the external force in the cylinder axis Z direction.

-Deformation by Y-direction external force-FIG. 14 shows that the Y-direction external force is applied to the inner cylindrical body 1 of the rubber elastic body 3 near the intersection of the one side overhanging portion 12 and the one side barrier portion 13. The shape before deformation (the shape indicated by the broken line) and the shape after the deformation (the shape indicated by the solid line) are shown.

According to this, the rubber elastic body portion on the front surface of the barrier portion 13 receives the force in the Y direction, and the protruding portion 12 extends laterally.
The rubber elastic body portion on the front side of each of the bulges is considerably bulged upward. That is, it is shown that the presence of the barrier portion 13 and the overhanging portion 12 further compresses the rubber elastic body 3 and increases the spring constant Ky with respect to the external force in the Y direction.

<Other Embodiments> The present invention is not limited to the above embodiments, but includes various other modifications. That is, in the above-described embodiment, the case in which the main body tubular portion 11, both overhanging portions 12 and 12, and both barrier portions 13 and 13 are integrally formed of the same material as the inner tubular body 1 has been described. The present invention is not limited to this.
2 and both barrier portions 13 and 13 may be integrally formed by molding using a hard resin, for example, nylon 66 mixed with glass fiber (for example, about 30%). This facilitates mass production of the inner cylinder body having different dimensions according to the performance required for the bush assembly.

In the above embodiment, the inner cylinder 1 is
Both overhang portions 12 and 12 and both barrier portions 1 with respect to the main body cylinder portion 11.
Although the shape in which 3 and 13 are attached is shown, the shape is not limited to this, and the inner cylinder may be shaped such that the main body cylinder is completely embedded in the overhanging portion and the barrier portion. For example, as shown in FIG. 15, the through hole 14 is formed along the axis Z of the cylindrical material.
Is formed into a main body cylindrical portion, and concave grooves 15, 15 are formed on the outer peripheral surface at the intermediate position in the axis Z direction to form the overhanging portions 12, 12 at both sides in the axis Z direction and the barrier portion 13, in the X direction. Thirteen
The inner cylindrical body 1'may be configured so as to form. Further, as shown in FIG. 16, the through hole 14 is drilled along the vertical axis Z of the prismatic material to form a main body cylindrical portion, and the concave grooves 15, 15 are formed on the outer peripheral surface at the intermediate position in the axial Z direction. The inner cylindrical body 1 ″ may be configured such that the overhanging portions 12 and 12 are formed at both side positions in the axis Z direction and the barrier portions 13 and 13 are formed in the X direction.

[0065]

As described above, according to the bush assembly of the first aspect of the present invention, since the projecting portions project from both sides in the cylinder axial direction of the main body cylindrical portion to both sides in the first direction, respectively. The rubber elastic body portion sandwiched between the pair of overhanging portions can be made dead rubber against external force from the cylinder axis direction, and the cylinder axis direction spring constant can be increased accordingly. On the other hand, with respect to the external force from the second direction, the external force is also applied to the rubber elastic body portion,
The second direction spring constant can be made soft.
Therefore, when a cylindrical outer cylinder is used and the end portion of the rubber elastic body is joined to the inner peripheral surface of the outer cylinder, which is the circumferential surface, the second elastic member tends to be harder than the cylinder axial direction spring constant. The directional spring constant can be made equal to or close to the cylinder axis directional spring constant by increasing the cylinder axis directional spring constant and decreasing the second directional spring constant. Moreover, such a change in the spring characteristic in the cylinder axis direction or the second direction can be easily performed by setting the size of the overhang portion.

On the other hand, with respect to the external force from the first direction, the length in the first direction in which the rubber elastic body is compressed by the thickness in the first direction of each of the barrier portions projecting from the cylindrical portion of the main body to both sides in the second direction. Is shortened, and since each of the barrier portions effectively compresses the rubber elastic body, the spring constant in the first direction can be made hard. Therefore, as the thickness of the barrier portion in the first direction increases, the spring constant in the first direction can be made harder, and even if the thickness of the barrier portion in the first direction is changed, Since it has almost no effect on the rubber elastic body portion that resists the external force from the cylinder axis direction and the second direction, it is independent of both the spring constants in the cylinder axis direction and the second direction and is in the first direction. The spring constant can be changed and set.

As described above, by using the inner cylindrical body having the barrier portion and the overhanging portion as in the present invention, the second axial direction is improved.
Direction, and the three spring constants for each direction of the first direction can be set independently of each other, and moreover, the setting according to the required performance can be easily performed by changing the dimensions of the barrier section or the overhanging section. You can Thereby, for example, it is possible to easily realize the required performance of the bush assembly in which the spring constant in the first direction is relatively hard and the spring constants in the cylinder axis direction and the second direction are the same or similar to each other. be able to.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the barrier portion of the inner cylindrical body projects over the entire width of the rubber elastic body in the second direction.
The increase in the first direction spring constant can be achieved more efficiently and effectively.

According to the third aspect of the invention, in addition to the effect of the first aspect of the invention, each of the overhanging portions of the inner cylindrical body is formed within the entire width of the rubber elastic body in the second direction. The increase of the spring constant in the cylinder axis direction and the decrease of the spring constant in the second direction can be achieved more efficiently and effectively.

According to the invention described in claim 4, in addition to the effect of the invention described in claim 1, each overhanging portion of the inner cylindrical body is provided over the same second direction range as the forming range of each barrier portion. Since the shape viewed from the cylinder axis direction is formed into a substantially quadrangle, the end surface of the rubber portion can be made a flat surface extending in the second direction to the cylinder axis direction external force, and the cylinder axis direction spring constant is increased, It is possible to efficiently reduce the second direction spring constant.

According to the invention of claim 5, in addition to the effect of the invention of claim 1, the first direction width of the barrier portion of the inner cylinder is within the range of the first direction width of the main body cylinder part. Since it is set, the first-direction spring constant can be increased within a range that does not affect the second-direction spring constant.

According to the sixth aspect of the invention, in addition to the effect of the first aspect of the invention, the respective barrier portions of the inner tubular body are integrally connected to the respective overhanging portions on both sides in the tubular axial direction. Therefore, each of the barrier portions and each of the overhanging portions that divides, forms or switches the rubber elastic body portion that expresses each spring constant in the cylinder axis direction, the second direction, and the first direction surely acts, respectively. Each rubber elastic body portion can reliably exhibit a predetermined spring constant in each direction.

According to the invention described in claim 7, in addition to the effect of the invention described in claim 1, in the inner cylinder body, the main body cylinder part, the respective overhanging parts, and the barrier part are integrally made of the same material. Since the inner cylindrical body is formed in the shape described above, the structural strength of the inner cylindrical body can be increased and the forming process can be rationalized.

According to the invention described in claim 8, in addition to the effect according to the invention described in claim 1, each overhanging portion and the barrier portion are different from the main body tubular portion with respect to the main body tubular portion. Since the inner cylinder is made of a single material, the desired size and shape can be adjusted according to the size settings of the overhangs and barriers that are changed according to the performance required at the site where this bush assembly is applied. The mass production of the inner cylinder can be easily manufactured.

Further, according to the invention of claim 9, the cylindrical outer cylindrical body is used as it is, and the end portion of the rubber elastic body is joined to the inner peripheral surface which is the circumferential surface of the outer cylindrical body. While the rubber elastic body portion between the two overhanging portions becomes dead rubber against the external force in the cylinder axial direction, it becomes an effective resistance element against the external force in the second direction, so that the spring constant in the cylindrical axis increases. The effect of the invention according to claim 1 that the second direction spring constant is reduced can be reliably obtained. As a result, it is possible to omit a troublesome process such as forming a thick portion on the inner peripheral surface of the outer cylindrical body, which is required in the conventional case.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB in FIG.

FIG. 4 is an enlarged perspective view of an inner cylinder.

FIG. 5 is a view corresponding to FIG. 1 showing a rubber elastic body when receiving an external force in the cylinder axis Z direction.

FIG. 6 is a view corresponding to FIG. 3, showing the rubber elastic body when an external force is applied to the cylinder axis Z direction.

FIG. 7 is a view corresponding to FIG. 1 showing the rubber elastic body when it receives an external force in the X direction.

FIG. 8 is an interval L1 of the overhanging portion and each spring constant Kz, Kx,
It is a relationship diagram with Ky.

FIG. 9 is a diagram showing the relationship between the wall thickness t of the barrier and spring constants Kz, Kx, and Ky.

FIG. 10: Overhang dimension W and spring constants Kz, Kx, K
It is a relational diagram with y.

FIG. 11 is an analytical model diagram showing a deformed state of the rubber elastic body at the position of the concave groove portion when receiving an external force in the X direction.

FIG. 12 is an analytical model diagram showing a deformed state of the rubber elastic body at the protruding portion position when an external force in the X direction is applied.

FIG. 13 is an analytical model diagram showing a deformed state of the rubber elastic body when an external force in the cylinder axis Z direction is applied.

FIG. 14 is an analytical model diagram showing a deformed state of the rubber elastic body when receiving an external force in the Y direction.

FIG. 15 is a perspective view showing another aspect of the inner cylinder.

16 is a perspective view showing another aspect of the inner cylinder different from FIG.

[Explanation of symbols]

 1, 1 ′, 1 ″ Inner cylinder 2 Outer cylinder 3 Rubber elastic body 11 Main body cylinder 12 Overhanging portion 13 Barrier 14 Through hole 15 Recessed groove Z Cylinder axis X X direction (second direction) Y Y direction (first (One direction)

Claims (9)

[Claims] 1. An inner cylinder body, an outer cylinder body that surrounds the inner cylinder body in parallel with the cylinder axis of the inner cylinder body, and extends from the inner cylinder body to both sides in a first direction orthogonal to the cylinder axis. In a bush assembly including a rubber elastic body that connects the outer surface of the inner cylinder and the inner surface of the outer cylinder to each other, the inner cylinder includes a main body cylinder into which a mounting shaft is inserted,
A pair of barrier portions projecting into the rubber elastic body and interposed in the rubber elastic body from both sides of the main body cylindrical portion in a second direction orthogonal to both the cylinder axis direction and the first direction; A pair of projecting portions projecting into the rubber elastic body from positions on both sides in the cylinder axial direction forming range of the rubber elastic body that are separated from each other in the cylinder axial direction of the main body cylindrical portion, to both sides in the first direction, A pair of recessed groove portions are provided at positions on both sides in the first direction with the main body tubular portion sandwiched therebetween, and the rubber elastic body is disposed between the surfaces of the pair of overhanging portions that face each other in the tubular axial direction. Characteristic bush assembly. 2. The bush assembly according to claim 1, wherein the barrier portion of the inner cylindrical body projects over the entire width of the rubber elastic body in the second direction. 3. The bush assembly according to claim 1, wherein each of the projecting portions on both sides of the inner cylindrical body in the cylinder axis direction is formed in a range over the entire width of the rubber elastic body in the second direction. 4. The shape according to claim 1, wherein each of the overhanging portions on both sides in the cylinder axis direction of the inner cylindrical body is provided over a second direction range that is the same as the forming range of the barrier section in the second direction. Is formed in a substantially square shape. 5. The bush assembly according to claim 1, wherein the barrier portion of the inner tubular body has a thickness in the first direction set within a range of a width of the main body tubular portion in the first direction. . 6. The bush assembly according to claim 4 or 5, wherein the barrier portion of the inner tubular body is integrally connected to the respective overhanging portions on both sides in the tubular axial direction. 7. The inner cylinder body according to claim 1, wherein the inner cylinder body has a main body cylinder portion, and the protrusions on both sides in a cylinder axis direction.
A bush assembly, wherein the barrier part and the barrier part are integrally formed of the same material. 8. The inner cylinder body according to claim 1, wherein, with respect to the main body cylinder part, each of the overhanging parts on both sides in the cylinder axis direction and the barrier part are integrally formed of a material different from the main body cylinder part. Bush assembly characterized in that 9. The bush assembly according to claim 1, wherein the outer cylinder is formed in a cylindrical shape.