JP2010048293A - Vibration control bush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration control bush capable of highly securing durability to a wrench and a twist, while enhancing a spring constant more than a conventional constant in the boring opposed direction in the direction for joining a pair of boring parts and the direction perpendicular to the axis in the orthogonal direction. <P>SOLUTION: In this vibration control bush 10, a first projection part 32 and a second projection part 34 are formed by projecting a part between the peripheral direction of the pair of boring parts 18 and 20 of an inner cylinder 12, and end parts 21 and 28 in the peripheral direction of the pair of boring parts 18 and 20 are formed as a first recessed part 72 and a second recessed part 73 in the shape of being recessed inside in the radial direction by going over a virtual circle 36. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration-isolating bushing that is suitable for a suspension bushing that is used in a suspension and that has an anti-vibration function. The present invention relates to a vibration-proof bushing suitable for use in

  2. Description of the Related Art Conventionally, an anti-vibration bush including a rigid inner cylinder and an outer cylinder and a cylindrical rubber elastic body sandwiched therebetween is widely used as a suspension bush or the like as an anti-vibration member for a vehicle.

  In this anti-vibration bushing, the rubber elastic body is provided with a straight portion (vacant space) penetrating in the axial direction at a position opposed to the direction perpendicular to the axis with the inner cylinder in between, and a pair of straight portions are opposed to each other (right facing The spring constant in the direction perpendicular to the axis of the vibration isolating bush is made different between the direction) and the direction perpendicular thereto.

  This type of anti-vibration bushing is conventionally used suitably as a compliance bushing that increases the longitudinal compliance of the suspension by absorbing the longitudinal force, for example, by applying the force received by the suspension in the longitudinal direction in the direction in which the spring is softened by forming the straight part It has been.

FIG. 9 shows what is disclosed in Patent Document 1 below as an example of its use as a compliance bush.
In this example, this type of anti-vibration bushing (compliance bushing) is used together with other ordinary anti-vibration bushings at the connecting portion between the lower arm (control arm) and the vehicle body side in the strut suspension.

  In the figure, reference numeral 200 denotes a tire, 202 denotes a lower arm, and the vehicle body side (vehicle inward side) is bifurcated into the front and rear. The side is elastically connected to the vehicle body side via a second anti-vibration bush (compliance bush) 206.

The first anti-vibration bushing 204 has a rigid inner cylinder 208 and a cylindrical rubber elastic body 210 vulcanized and bonded around the inner cylinder 208. The rubber elastic body 210 is provided at the front end of the lower arm 202. It is press-fitted into a cylindrical portion 212 having a cylindrical shape and assembled.
Here, the first anti-vibration bushing 204 is used in a horizontal type in which the bush axis is oriented sideways (front-rear direction).
That is, the inner cylinder 208 and the rubber elastic body 210 are front and rear and are press-fitted into a cylindrical portion 212 that is also formed in the front and rear direction, so that the inner cylinder 208 is fixed to the vehicle body side.

On the other hand, the second anti-vibration bush 206 is used in a vertical type in which the bush axis is oriented vertically (vertically).
The second anti-vibration bush 206 has a rigid inner cylinder 212 and outer cylinder 214, and a rubber elastic body 216 sandwiched between them. The inner cylinder 212, the outer cylinder 214, and the rubber elastic body 216 are connected to each other. In a vertically oriented state, it is press-fitted vertically into a cylindrical tubular portion 218 at the rear end of the lower arm 202 that is also formed in the longitudinal direction, and is assembled and held there.
The second vibration isolating bush 206 is also fixed to the vehicle body side in the inner cylinder 212, and elastically connects the rear end portion of the lower arm 202 to the vehicle body side.

In the second vibration isolating bush 206, the rubber elastic body 216 is provided with a pair of straight portions 220 at positions facing each other in the direction perpendicular to the axis with the inner cylinder 212 therebetween.
Here, each of the pair of straight portions 220 is provided along the circumferential direction in a shape penetrating in the axial direction.

In the second vibration isolating bushing 206 by a pair of hollow portions 220 are provided, the direction in which they hollow portion 220 faces soft is X ₁ direction of the spring constant is (currants opposing direction), of which the perpendicular direction The spring constant increases.

For the second vibration isolating bushing 206, toward the currants opposite direction in the lateral direction of the vehicle (but strictly direction X ₁ direction is inclined at an angle α with respect to X ₂ direction, which is the left-right direction of the vehicle), also this As a result, the spring constant can be increased in the vehicle front-rear direction and the steering stability can be improved, while the spring constant can be lowered and softened in the vehicle left-right direction. Thus, it is possible to satisfactorily absorb the shock and vibration when the tire 200 rides over the road joints and protrusions while the vehicle is running.

  When the tire 200 gets over a seam or protrusion on the road surface, the lower arm 202 tries to rotate in the direction indicated by the arrow P in the drawing with the connection point of the first vibration isolating bush 204 as a fulcrum. It has a soft spring characteristic in the applied input direction and can easily follow and deform, thereby satisfactorily mitigating the impact applied to the tire 200 and effectively suppressing the impact from being transmitted to the vehicle body side. it can.

By the way, when the second vibration isolating bush 206 is used as a vertical type compliance bush in this way, the lower arm 202 is connected to the vehicle body side by the first vibration isolating bush 204 and the second anti-vibration bush 206 as the tire 200 moves up and down. When pivoting up and down with the connecting point as a fulcrum, a large squeezing force is applied to the vertically installed second anti-vibration bush 206.
Here, the twisting force is a force in a direction in which the outer cylinder 214 is tilted with respect to the axial direction with respect to the inner cylinder 212.

Thus, when such a large twisting force acts on the second vibration isolating bushing 206, a large tensile force acts on the rubber elastic body 216, and in particular, the rubber elastic body 216 at the circumferential ends of the pair of straight portions 220. In particular, large strains and stresses act locally.
This greatly affects the durability of the second anti-vibration bush 206, and becomes a factor of reducing its durability life.

Meanwhile In the second vibration damping bush 206 is in enhancing the steering stability as described above, it is desirable to increase the currant opposing direction (X ₁ direction) orthogonal direction of the spring constant.
As a means of increasing the X ₁ direction and the orthogonal direction of the spring constant is currant opposite direction, increasing the rubber hardness of the rubber elastic body 216, located in the orthogonal direction of the rubber elastic body 216 of the inner cylinder 212 and a larger diameter There are means such as reducing the thickness of the rubber main body 216A (thickness between the inner cylinder 212 and the outer cylinder 214) and increasing the axial length of the rubber main body 216A. However, the durability of the second anti-vibration bushing 206 in the above-described twisting direction is lowered.

The above-described twisting deformation applied to the vertical second vibration-proof bushing 206 is a constant displacement deformation in which the deformation amount is determined by the displacement of the lower arm 202. In this case, when the rubber hardness of the rubber elastic body 216 increases, the rubber elastic body 216 increases. In addition, the strain and stress generated in the rubber elastic body 216 under constant deformation increase in addition to the decrease in the elongation of the rubber, and even when the thickness of the rubber body 216A is reduced, the rubber under constant displacement The strain and stress generated in the elastic body 216 become large.
Further, even when the axial length of the rubber main body 216A is increased, the strain and stress generated in the rubber elastic body 216 under a constant displacement are increased, and both are in the direction of reducing the durability life against the above-described twist deformation.

  The anti-vibration bush having the above-described configuration having a pair of curving portions is also used as a trailing arm bush (compliance bush) of a vehicle. It becomes a big problem.

In addition, as an example in which a vibration-proof bushing having a curving portion on a rubber elastic body is used as a compliance bush, there is one disclosed in Patent Document 2 below.
As another prior art, Patent Document 3 below discloses an inner cylinder having an irregular shape with a rectangular cross section.
However, this is different from the present invention in that the rubber elastic body does not have a straight portion.

JP 2002-337527 A JP 2005-249022 A JP-A-10-272523

The present invention is based on the circumstances as described above, and it is possible to increase the spring constant in the direction perpendicular to the axis perpendicular to the direction opposite to the direction in which the pair of corners are connected to each other while increasing the spring constant. The object of the present invention is to provide a vibration-proof bushing that can maintain the durability against the same as or higher than the conventional one.
Another object of the present invention is to provide an anti-vibration bush that can increase the spring characteristics in the facing direction as well as the stopper characteristics in the facing direction when used as a compliance bush. is there.

  Thus, the present invention has a rigid inner cylinder and outer cylinder, and a cylindrical rubber elastic body sandwiched between the inner cylinder and the outer cylinder, and the rubber elastic body includes: An anti-vibration bush having at least a pair of straight portions penetrating in the axial direction and extending in the circumferential direction at a position facing the direction perpendicular to the axis with the inner cylinder interposed therebetween, A portion located between the circumferential directions of the pair of straight portions is partially protruded radially outward toward the outer cylinder along the axial direction to form a first protrusion, and the first protrusion On the opposite side, a portion of the inner cylinder positioned between the pair of straight portions in the circumferential direction faces the outer cylinder along the axial direction, and radially outwards in the direction opposite to the first protrusion. A second protrusion is formed by partially protruding so that the inner cylinder has an irregular shape with a non-circular cross-sectional shape. A first virtual circle passing through the projecting end of the first projecting portion with the circumferential end on the first projecting portion side of one of the curled portions as the center of the transverse section of the inner cylinder. As a first recessed portion having a shape that is recessed inward in the radial direction, the second protruding portion has a circumferential end on the second protruding portion side of the other straight portion, the center of the inner cylinder being the center. It is characterized by being formed as a second recessed portion having a shape that is recessed inward in the radial direction beyond the second imaginary circle passing through the protruding end.

  According to a second aspect of the present invention, the second end of the first aspect has a shape in which a circumferential end portion of the one straight portion on the second projecting portion side is recessed inward in the radial direction beyond the second virtual circle. As the recessed portion, the circumferential end portion on the first protruding portion side of the other straight portion is formed as a first recessed portion having a shape that is recessed radially inward beyond the first virtual circle. It is characterized by that.

  According to a third aspect of the present invention, in the first aspect, between the portion of the inner cylinder located between both ends in the circumferential direction of the one straight portion and the both ends in the circumferential direction of the other straight portion. Each of the positioned portions extends along the axial direction and extends radially beyond the radially inner end of the first recessed portion of the one straight portion and the radially inner end of the first recessed portion of the other straight portion. It is formed as a third protrusion having a shape protruding outward and in opposite directions.

  According to a fourth aspect of the present invention, in the second aspect of the present invention, between the portion of the inner cylinder located between both ends in the circumferential direction of the one straight portion and the both ends in the circumferential direction of the other straight portion. The portions located along the axial direction are respectively radially inner ends of the first recessed portion and the second recessed portion of the one curled portion, and the first recessed portion and the first recessed portion of the other curled portion. It is characterized by being formed as a third projecting portion having a shape projecting radially outward and opposite to each other across the radially inner ends of the two recessed portions.

  According to a fifth aspect of the present invention, in any one of the third and fourth aspects, the inner cylinder has a cross-sectional shape as a whole formed by the first projecting portion, the second projecting portion, and the third projecting portion. It is characterized by being.

Effects and effects of the invention

  As described above, according to the present invention, a portion between the circumferential portions of the pair of straight portions of the inner cylinder is partially protruded radially outward toward the outer cylinder along the axial direction to form the first protrusion. In addition, on the side opposite to the first projecting portion, the portion between the pair of straight portions of the inner cylinder is directed radially toward the outer cylinder along the axial direction in the direction opposite to the first projecting section. A second projecting portion is formed by partially projecting outward, so that the inner cylinder has an irregular shape with a non-circular cross-sectional shape, and the first projecting portion of one of the pair of curled portions The circumferential end on the part side is formed as a first recessed portion having a shape that is recessed radially inward beyond the first virtual circle passing through the protruding end of the first protruding portion, and the second protruding portion of the other straight portion As a second recessed portion having a shape in which the circumferential end on the portion side is recessed radially inward beyond the second virtual circle passing through the protruding end of the second protruding portion It is obtained by respectively formed.

According to the present invention, it is possible to effectively increase the spring characteristics in the direction perpendicular to the opposing direction, while maintaining the durability against twisting and torsional deformation at the same level or higher.
The reason is as follows.

  As described above, the spring constant (spring characteristic) of the rubber elastic body, that is, the anti-vibration bushing in the direction perpendicular to the opposite direction is increased by increasing the diameter of the cylindrical inner cylinder and the inner cylinder and the outer cylinder in the same direction. It can be increased by reducing the rubber thickness between them.

However, if this is done, the rubber wall thickness between the inner cylinder and the outer cylinder will be reduced over the entire circumference, and the radial dimensions of both ends in the circumferential direction of the pair of curving parts will inevitably be inevitable. Will become smaller.
When deformation such as twisting or twisting is applied, the place where the most strain and stress are concentrated is the circumferential end of the straight part, and usually a crack occurs at the circumferential end, and the crack progresses from there. Endurance life is reached.

In this case, if the radial dimension of the circumferential end portion of the straight portion is reduced and the inner peripheral length of the end portion is shortened, the deformable free length is shortened and the specific portion of the circumferential end portion is weak in strength. Strain and stress tend to concentrate on the surface, and cracks are easily generated and proceed from there, resulting in a decrease in durability.
That is, when the spring characteristic in the direction perpendicular to the facing direction is increased simply by increasing the diameter of the inner cylinder, the durability due to deformation such as twisting or torsion decreases.

On the other hand, in the present invention, the first projecting portion and the second projecting portion are formed by partially projecting each of the portions located between the circumferential directions of the pair of straight portions of the inner cylinder in mutually opposite directions in the radial direction. Thus, the rubber elastic body is partially thinned in the circumferential direction at the portions where the first protrusion and the second protrusion are formed, more specifically, in the direction perpendicular to the opposing direction, while the first protrusion , A rubber thickness is secured for the portion around the second projecting portion (circumferential direction), the circumferential end on the first projecting portion side of one of the pair of the curled portions, the other curled portion The circumferential end on the second projecting portion side of the first projecting end of the first projecting portion extends beyond the first imaginary circle passing through the projecting end of the first projecting portion and the second imaginary circle passing through the projecting end of the second projecting portion. The first concave part and the second concave part of the concave shape are used to increase the radial dimension and to increase the inner peripheral length. According to the present invention, when a twisting or torsional deformation is applied, distortion and stress generated at the circumferential end of the straight portion are absorbed and relaxed by a large inner circumferential length (free length). It is possible to prevent a large strain or stress from acting on a specific portion of the end portion.
As a result, it is possible to suppress a decrease in durability due to twisting or torsional deformation, and to ensure high durability against such deformation.

In the present invention, the protrusion heights of the first protrusion and the second protrusion can be changed variously, and the spring characteristics in the direction perpendicular to the opposing direction can be appropriately tuned accordingly.
In this case, it is possible to make the protrusion heights of the first protrusion and the second protrusion different, but in the present invention, the protrusion heights of the first protrusion and the second protrusion are the same. Can be left as
In this case, the first virtual circle and the second virtual circle are the same virtual circle.

In the present invention, the circumferential end on the second projecting portion side of the one straight portion is a second concave portion having a shape that is recessed radially inward beyond the second virtual circle, and the other straight portion The circumferential end on the first projecting portion side can be formed as a first recessed portion having a shape that is recessed radially inward beyond the first imaginary circle (claim 2).
By doing in this way, durability with respect to the deformation | transformation of a twist direction and a twist direction can be improved further.

  In the present invention, each of the portion located between the circumferential ends of one of the straight portions of the inner cylinder and the portion located between both circumferential ends of the other straight portion are arranged along the axial direction. It can be formed as a third projecting portion having a shape projecting radially outward in opposite directions toward the outer cylinder (claims 3 and 4).

In this case, the rubber thickness can be reduced immediately in the opposing direction, and the rubber thickness can be tuned to various rubber thicknesses by changing the protruding height of the third protruding portion.
Further, the protruding height of the third protruding portion can be determined independently of the protruding heights of the first and second protruding portions, and therefore the rubber thickness in the opposite direction is also the rubber thickness in the orthogonal direction. It can be determined independently of the thickness.

  In these third and fourth aspects, the pair of straight portions can be provided at a radial intermediate position between the third projecting portion on the inner cylinder side and the outer cylinder, and in this case, the rubber on the inner cylinder side The elastic body can be used as an inner peripheral rubber stopper, and the outer cylinder can be used as an outer peripheral rubber stopper.

  That is, when the inner cylinder and the outer cylinder are relatively displaced in the direction perpendicular to the axis so as to fill the gap between the straight parts, when the displacement tends to increase beyond a certain level, the inner peripheral rubber stopper and the outer rubber stopper It is possible to restrict excessive displacement in the same direction by acting as a stopper by contact with the portion.

  At that time, by forming the third protrusion on the inner cylinder side, the rubber thicknesses of the inner peripheral rubber stopper and the outer peripheral rubber stopper are reduced, and the spring characteristics in the direction perpendicular to the axis in the opposing direction are hardened. Therefore, it is possible to act as a stopper with high efficiency, that is, to increase the effectiveness of the stopper.

  Therefore, when the vibration-proof bushing is used as a compliance bushing (second bushing) as shown in FIG. 9, the tire 200 is controlled so as not to move excessively in the front-rear direction with respect to the vehicle body during braking or starting of the vehicle. Stability can be effectively increased.

  In the present invention, the first projecting portion, the second projecting portion, and the third projecting portion can configure the inner cylinder so that the cross-sectional shape as a whole forms a cross shape (Claim 5).

Next, embodiments of the present invention will be described in detail with reference to the drawings.
In FIG. 1, reference numeral 10 denotes an anti-vibration bush according to the present embodiment, which is sandwiched between a metallic rigid inner cylinder 12, a metallic rigid outer cylinder 14 provided concentrically with the inner cylinder 12, and them. And a cylindrical rubber elastic body 16. Here, the rubber elastic body 16 is integrally vulcanized and bonded to the inner cylinder 12 and the outer cylinder 14.

In the rubber elastic body 16, a pair of straight portions (voids) 18 and 20 extending in the circumferential direction penetrate the rubber elastic body 16 in the axial direction at positions facing each other in the direction perpendicular to the axis with the inner cylinder 12 therebetween. It is provided in the form to do.
One curb portion 18 has circumferential end portions (hereinafter simply referred to as end portions) 21 and 22 and a slit-like portion 24 therebetween.
The other straight portion 20 also has circumferential end portions (hereinafter simply referred to as end portions) 26 and 28 and a slit-like portion 30 therebetween.

In this embodiment, the outer cylinder 14 is made of steel, while the inner cylinder 12 is made of an extruded material of an aluminum alloy material.
The aluminum alloy inner cylinder 12 has a center hole 50 penetrating in the axial direction, and a portion between the end portions 21 and 26 on the same side in the circumferential direction of the pair of straight portions 18 and 20 is The first projecting portion 32 is formed by projecting radially outward toward the outer cylinder 14 over the entire axial length.
Further, the portion between the end portions 22 and 28 on the opposite side of the first protrusion portion 32 of the pair of straight portions 18 and 20 protrudes radially outward toward the outer tube 14 over the entire length in the axial direction. The second projecting portion 34 is formed by the caulking.

  As shown in FIG. 3, the anti-vibration bush 10 has a rubber elastic body 16 between the first projecting portion 32 and the outer tube 14 and between the second projecting portion 34 and the outer tube 14. The rubber elastic body 16 is buried in the entire direction, and the rubber elastic body 16 in the portion between the first projecting portion 32 and the outer tube 14 and the portion between the second projecting portion 34 and the outer tube 14 is a rubber body portion. 16A.

In Figure 1, X ₁ direction represents the currant opposite direction (direction connecting the respective circumferential direction of the center of the hollow portions 18, 20) is the direction in which a pair of hollow portions 18, 20 are opposed to each other and X ₃ direction indicates a direction perpendicular to the X ₁ direction.
In this embodiment, the inner cylinder 12 are allowed to protrude into the first projecting portion 32 second projecting portion 34 and the X ₃ direction, also in the X ₁ direction is currant opposite direction, over the entire axial length Projecting outward in the radial direction toward the outer cylinder 14, and the projecting portions form third projecting portions 38 and 40.
That is, in this embodiment, the cross-sectional shape of the inner cylinder 12 has a cross shape.

A recess 42 is formed between the first protrusion 32 and the third protrusion 38, and a recess 44 is formed between the third protrusion 38 and the second protrusion 34.
Further, a recess 46 is formed between the second protrusion 34 and the third protrusion 40, and a recess 48 is formed between the third protrusion 40 and the first protrusion 32.

The first projecting portion 32, the second projecting portion 34, and the third projecting portions 38, 40 each have a substantially rectangular cross-sectional shape.
Specifically, the first projecting portion 32 is a circular arc surface of the same large radius with an imaginary circle 36 which circumference of the protruding end will be described later, also a pair of side surfaces of the upper and lower in FIG. 1, a straight line in the direction parallel to the X ₃ direction The surface extends in a shape.

In this embodiment, the first projecting portion 32, the second projecting portion 34, and the third projecting portions 38, 40 all have the same shape. Therefore, the peripheral surface of the projecting end of the second projecting portion 34 is also virtual. is a circle 36 and the same large radius arcuate surfaces, also the pair of upper and lower sides, there is a surface extending linearly in X ₃ direction parallel to the direction.

A third protrusion 38, 40 is also circumferential surface of the projecting end are arc surface having a larger radius of the same virtual circle 36, further parallel to the straight line each pair of left and right side surfaces of the X ₁ direction It is an extended surface.
In addition, each side surface is mutually connected by the circular arc surface in each cross | intersection part.

  The end portion 21 on the first protruding portion 32 side of the straight portion 18 is centered on the center of the cross section of the inner cylinder 12, and the first protruding portion 32, the second protruding portion 34, and the third protruding portion 38 of the inner cylinder 12. , 40 through a protruding circle 36 passing through each projecting end, and a first recessed portion 72 having a shape recessed inward in the radial direction is formed.

Similarly, the end portion 28 on the second projecting portion 34 side of the straight portion 20 also forms a second recessed portion 73 having a shape recessed beyond the virtual circle 36 inward in the radial direction.
Furthermore, the end 22 on the second protrusion 34 side of the curled portion 18 and the end 26 on the first protrusion 32 side of the curled portion 20 are also indented radially inwardly beyond the virtual circle 36. Two concave portions 74 and a first concave portion 75 are formed.

All of these end portions 21, 22, 26, and 28 enter recesses 42, 44, 46, and 48 formed between the projecting portions of the inner cylinder 12.
The straight portions 18 and 20 each have a symmetrical shape, and the straight portions 18 and 20 have a vertically symmetrical shape.

As shown in detail in FIG. 5, the end portion 21 on the first projecting portion 32 side of the straight portion 18 has an arc surface with a circumferential end surface 52 having a radius R ₁ . The upper part has a shape recessed outward in the radial direction from the slit-like part 24.
Its inner surface of the concave portion is a circular arc surface having a radius R _2, arcuate surface of the radius R ₂ is, are continuous with respect to the circumferential end face 52.

On the other hand, the circumferential inner surface 54 in the vertical direction in the drawing of the end portion 21, that is, the surface extending linearly in X ₁ direction parallel direction in FIG. 1, and this straight circumferential inner surface 54, the radius R The circular arc surface ₃ is connected to the circumferential end surface 52.

The other end 22 in the circumferential direction of the straight portion 18 is symmetrical to the end 21.
Further, the end portion 26 of the other straight portion 20 has a vertically symmetrical shape with the end portion 21, and the end portion 28 of the straight portion 20 has a vertically symmetrical shape with the end portion 22 of the straight portion 18.

The straight portion 18 has a width between the end portions 21 and 22 in the circumferential direction wider than the width of the third projecting portion 38, and the third projecting portion of the inner cylinder 12 between the end portions 21 and 22. 38 sticks out.
That is, the portion of the inner cylinder 12 between the end portions 21 and 22 of the straight portion 18 protrudes radially outward from the radially inner end positions of the end portions 21 and 22 over the entire axial length. It has been.

Similarly, in the other straight portion 20, the width between the end portions 26 and 28 in the circumferential direction is wider than the width of the third projecting portion 40, and the third projecting portion is between the end portions 26 and 28. The part 40 protrudes.
That is, the third protrusion 40 is protruded radially outward beyond the radially inner end positions of the end portions 26 and 28.

The pair of straight portions 18 and 20, more specifically, each of the slit-like portions 24 and 30 is provided at an intermediate position in the radial direction between the third projecting portions 38 and 40 and the outer cylinder 14. 10, the rubber elastic body 16 are divided into X ₁ direction in the portion of these hollow portions 18, 20 (vertical direction in the drawing), the inner peripheral side rubber stopper 56 of the inner cylinder 12 side, the outer cylinder 14 side and the outer rubber stopper 58 is caused to face each other with a hollow portion 18 in the X ₁ direction.
In hollow portion 20 side, the inner peripheral side rubber stopper 60 of the inner cylinder 12 side and the outer peripheral side rubber stopper 62 of the outer cylinder 14 side is made to face the X ₁ direction in the drawing at a hollow portion 20 Yes.

Each inner peripheral surface of the pair of outer peripheral side rubber stoppers 58 and 62 has a concavo-convex shape having a continuous wave shape along the circumferential direction.
The uneven shape of the inner peripheral surface of each of the outer peripheral rubber stoppers 58 and 62 is such that the outer peripheral side from the inner peripheral rubber stoppers 56 and 60 when the stopper is in contact with the inner peripheral rubber stopper 56 or 60. It is provided to prevent the generation of abnormal noise when the rubber stopper portions 58 and 62 are separated.
As shown in FIG. 4, the straight portion 18 is formed over the angle θ ₁ in the circumferential direction, and the straight portion 20 is formed over the angle θ ₂ in the circumferential direction.
Here theta ₁ is a θ _1> θ ₂ with respect to theta _2.

Further, the width T ₁ between the end portions 21 and 22 in the straight portion 18 is slightly larger than the width T ₂ between the end portions 26 and 28 of the straight portion 20.
On the other hand, the width dimensions of the third projecting portions 38 and 40 of the inner cylinder 12 are the same, and therefore the width of the inner peripheral rubber stopper portion 56 on the straight portion 18 side is equal to the inner peripheral rubber stopper portion 60 on the straight portion 20 side. The size is slightly larger than the width.

  Further, the outer peripheral rubber stopper of the inner peripheral rubber stopper portion 56 on the curled portion 18 side and the peripheral surface serving as a stopper surface facing the outer peripheral rubber stopper portion 58 and the inner peripheral rubber stopper portion 60 on the curled portion 20 side. The peripheral surface serving as a stopper surface facing the portion 62 is an arc surface centering on the center of the inner cylinder 12 in the cross-sectional shape, whereas the side surface of the straight portion 18 as shown in FIG. The inner circumferential rubber stopper portion 56 and the inner circumferential rubber stopper portion 60 on the straight portion 20 side have different vertical cross-sectional shapes.

That is, as shown in FIG. 2, the inner peripheral rubber stopper 56 on the side of the straight portion 18 protrudes most toward the outer peripheral rubber stopper 58 at the intermediate portion in the axial direction, and away from both sides in the axial direction. Has a shape that is one step lower than the center.
In the figure, reference numeral 56-1 represents a central peak protruding most toward the outer peripheral rubber stopper 58, and reference numeral 56-2 represents a stepped portion that is lowered by one step toward the radial center. .

On the other hand, the inner peripheral rubber stopper portion 60 on the curled portion 20 side protrudes the largest in the outer peripheral rubber stopper portion 62 at the axial center portion, and the protrusion amount decreases continuously as the axial portion moves away from the protruding portion. It has a smoothly continuous mountain shape.
In the figure, reference numeral 60-1 represents the axially central peak closest to the outer peripheral rubber stopper 62.

On the other hand, each of the outer peripheral side rubber stoppers 58 and 62 is a linear surface with the inner peripheral surface 64 extending in parallel to the axial direction.
As shown in FIG. 2, the minimum gap d ₁ on the side of the straight part 18 is smaller than the minimum gap d ₃ on the side of the straight part 20, and the total dimension of d ₁ and d ₂ is d. ₃ and approximately the same size.

The anti-vibration bush 10 of this embodiment can be suitably used, for example, as a compliance bush (second bush) of the suspension shown in FIG.
FIG. 6 shows the vibration isolating bush 10 at this time together with a part of the lower arm 202 in an assembled state.
In this, as shown in FIG, vibration damping rubber bushing 10 is the X ₁ direction is currant opposing direction, is used mounted in a state of being inclined by an angle α with respect to X ₂ direction of the vehicle transverse direction.

FIG. 1 shows the shape of the stage where the vibration isolating bushing 10 is vulcanized and molded. The anti-vibration bushing 10 is the cylinder of the lower arm 202 after the outer cylinder 14 is drawn in the reduced diameter direction from this state. It is press-fitted into the shaped part 218 and assembled.
The anti-vibration bushing 10 is formed by drawing the outer cylinder 14 from the vulcanized shape shown in FIG. 1, so that the shape of the rubber elastic body 16 slightly changes, but the degree of change is small. The end portions 21, 22, 26, and 28 in the straight portions 18 and 20 basically retain their shapes.

If the vibration damping bushing 10 of the present embodiment is used this way, the rubber thickness of the X ₃ direction which is orthogonal direction to the X ₁ direction is currant opposing direction thinned, the X ₃ direction of the spring characteristics By making it hard, the spring characteristic in the vehicle front-rear direction in the vibration isolating bush 10 can be hardened, and the steering stability can be improved.
On the other hand, even when the suspension arm 202 rotates up and down with the vibration isolating bush 10 as a fulcrum as the tire moves up and down, and the twisting force is repeatedly applied to the vibration isolating bush 10, the durability of the vibration isolating bush 10 is kept high. can do.

That is, by increasing the diameter merely diameter of the inner cylinder 12a of the cylindrical as shown in Comparative Example Figure in FIG. 7 (A), in the direction orthogonal to the X ₁ direction is currant opposite direction X ₃ direction When the spring characteristics are hardened, the durability is reduced due to the twisting deformation (K in the figure represents a crack generated at the end 21a).

  On the other hand, as shown in the comparative example of FIG. 7B, when the inner cylinder 12b is kept small and the radial thickness of the rubber elastic body 16b is kept thick, the rubber elasticity at the time of twisting deformation is obtained. A large amount of elastic deformation of the body 16b can be secured, and the end portions 21b, 22b, 26b, and 28b of the pair of straight portions 18b and 20b can be made large in the radial direction. A large inner peripheral length can be secured.

In this case, since distortion and stress can be dispersed and alleviated over the entire long inner peripheral length (free length) of the end portions of the straight portions 18b and 20b, large strain is concentrated on a specific portion of the end portion. It can suppress that a stress generate | occur | produces and a crack generate | occur | produces there.
If on the one hand this is done, the X ₃ direction which is orthogonal direction to the X ₁ direction is currant opposing direction, radial thickness of the rubber elastic body 16b is thick, that the spring characteristics in the same direction is soft End up.

On the other hand, in the present embodiment, each of the portions located between the circumferential directions of the pair of straight portions 18 and 20 of the inner cylinder 12 is partially protruded in the opposite directions in the radial direction, thereby causing the first protruding portion 32. the second protrusion 34 is formed, thereby a rubber elastic body 16 which first projecting portion 32, partially circumferentially forming portion of the second projecting portion 34, details currants opposing direction (X ₁ direction) and while thinly in the orthogonal direction (X ₃ direction), they first projecting portion 32, portions around the second protrusions 34 (around the circumferential direction) to secure thicker rubber wall, a pair of hollow portions 18, The end portion 21 on the side of the first protrusion 32 and the end portion 28 on the side of the second protrusion 34 of the other straight portion 20 are respectively connected to the protrusion end of the first protrusion 32 and the second protrusion 34. A virtual circle 36 passing through the protruding end is recessed beyond the radially inward side. The first concave portion 72 and the second concave portion 73 have a large radial dimension and a large inner circumferential length, so that when the twist deformation is applied, the circumference of the straight portions 18 and 20 is increased. Strain and stress generated in the direction end portions 21 and 28 can be absorbed and relaxed with a large inner peripheral length (free length), and large strain and stress are prevented from acting intensively on specific portions of the end portions 21 and 28. be able to.
As a result, it is possible to suppress a decrease in durability due to the twisting deformation and to ensure a high durability against the twisting deformation.

In this embodiment, the first projecting portion 32, it is possible to variously change the projection height of the second projecting portion 34 can be appropriately tuned to the X ₃ direction of the spring characteristics accordingly.
In the present embodiment, the end portion 22 on the second projecting portion 34 side of the straight portion 18 and the end portion 26 on the first projecting portion 32 side of the straight portion 20 also extend beyond the first virtual circle 36 to the inside in the radial direction. It forms as the 2nd recessed part 74 and the 1st recessed part 75 of the recessed shape, respectively, By doing in this way, durability with respect to the deformation | transformation of the anti-vibration bush 10 in the twist direction can be improved further.

Furthermore, in this embodiment, each of the part located between the circumferential direction both ends of the straight part 18 of the inner cylinder 12 and the part located between the circumferential direction both ends of the straight part 20 is made into the axial direction full length. over and since that is formed as a third projecting portion 38, 40 having a shape projecting in opposite directions radially outward from each other toward the outer cylinder 14, can reduce the rubber thickness in the X ₁ direction currant opposite direction, The thickness of the rubber can be tuned in various ways by changing the protrusion height of the third protrusions 38 and 40.
Projecting height of the third protrusion 38, 40 may define independently of the projecting height of the first and second projecting portions 32 and 34 described above thus also the rubber thickness in the X ₁ direction also, and this rubber thickness of X ₃ direction orthogonal directions and can be determined independently.

  In the vibration isolating bush 10 of the present embodiment, when the inner cylinder 12 and the outer cylinder 14 are relatively displaced in the direction perpendicular to the axis so as to fill the gap between the straight portions 18 and 20, the displacement tends to increase beyond a certain level. Sometimes, the inner peripheral rubber stopper portions 56, 60 and the outer peripheral rubber stopper portions 58, 62 are brought into contact with each other to restrain the excessive displacement in the same direction.

At that time, by forming the third protrusions 38 and 40 on the inner cylinder 12 side, the rubber thicknesses of the inner peripheral side rubber stoppers 56 and 60 and the outer peripheral side rubber stoppers 58 and 62 are reduced, so it is possible to harden the direction perpendicular to the axis of the spring characteristics in the X ₁ direction, those by effective high stopper function, that is, to increase the effectiveness of the stopper.

  Therefore, when the vibration isolating bushing 10 is used as a compliance bushing (second bushing) as shown in FIG. 9, the tire 200 is restrained from excessively moving in the front-rear direction with respect to the vehicle body during braking or starting of the vehicle. Steering stability can be effectively increased.

Although the embodiment of the present invention has been described in detail above, this is merely an example.
For example, as shown in FIG. 8A, the first protrusion 32 and the second protrusion 34 are partially provided with a recess 68, and the first protrusion 32 and the second protrusion 34 are formed into two protrusions. It is possible in some cases to include the portions 32-1, 32-2, 34-1 and 34-2, and as shown in FIG. As a shape, a flat portion 70 is provided at each apex, and the first projecting portion 32 and the second projecting portion 34 are formed at a pair of apexes facing each other, and the third projecting is performed at a pair of apexes facing each other in the orthogonal direction. It is also possible to configure the sections 38 and 40.

The present invention can also be applied to a compliance bushing of a trailing arm bush that elastically connects a vehicle's trailing arm and the vehicle body side (in this case, the vibration isolating bush can be used in a lateral position). In this case, high durability against torsional deformation of the trailing arm bush can be ensured.
In addition, this invention can be comprised in the form which added the various change in the range which does not deviate from the meaning.

It is a figure which shows the vibration proof bush of one Embodiment of this invention. It is II-II sectional drawing of FIG. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a figure for demonstrating the dimensional relationship of each part of the anti-vibration bush of FIG. It is the figure which expanded and showed the principal part of the vibration isolating bush of the same embodiment. It is the figure which showed the vibration isolating bush of the embodiment with the one part in the assembly | attachment state to a lower arm. It is the comparative example figure shown in order to demonstrate the advantage of the vibration isolating bush of the embodiment. It is a figure of the vibration proof bush of other embodiment of this invention. It is the figure which showed the conventionally well-known vibration-proof bush with the lower arm in the assembly | attachment state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Anti-vibration bush 12 Inner cylinder 14 Outer cylinder 16 Rubber elastic body 18,20 Straight part 21,22,26,28 Circumferential edge part 32 1st protrusion part 34 2nd protrusion part 36 Virtual circle 38,40 3rd protrusion part 72,75 1st recessed part 73,74 2nd recessed part

Claims (5)

A rigid inner cylinder and an outer cylinder, and a cylindrical rubber elastic body sandwiched between the inner cylinder and the outer cylinder, and a direction perpendicular to the axis between the rubber elastic body and the inner cylinder A vibration-proof bushing provided with at least one pair of straight portions extending in the axial direction and extending in the circumferential direction at a position opposite to the inner cylinder, and positioned between the inner cylinders in the circumferential direction of the pair of straight portions The first projecting portion is formed by partially projecting a portion to be radially outward toward the outer tube along the axial direction, and on the side opposite to the first projecting portion, the inner tube, A portion located between the circumferential directions of the pair of straight portions is partially protruded radially outward in the opposite direction to the first protrusion toward the outer cylinder along the axial direction, and the second protrusion is formed. Forming the inner cylinder with a non-circular irregular shape in cross section,
A circumferential end on the first protruding portion side of one of the pair of straight portions is a first passing through the protruding end of the first protruding portion with the center of the cross section of the inner cylinder as the center. As a first recessed portion having a shape that is recessed inward in the radial direction beyond the virtual circle, a circumferential end on the second protruding portion side of the other straight portion is centered on the center of the inner cylinder, and the second An anti-vibration bush characterized by being formed as a second recessed portion having a shape that is recessed radially inward beyond a second imaginary circle passing through the protruding end of the protruding portion.   In Claim 1, as the second recessed portion having a shape in which a circumferential end portion on the second projecting portion side of the one straight portion is recessed radially inward beyond the second virtual circle, The anti-vibration device is characterized in that a circumferential end portion of the straight portion on the first projecting portion side is formed as a first recessed portion having a shape that is recessed inward in the radial direction beyond the first virtual circle. bush.   2. The portion of the inner cylinder, which is located between both ends in the circumferential direction of the one straight portion, and a portion located between both ends in the circumferential direction of the other straight portion are each axial. Along the radial inner end of the first concave portion of the one straight portion and the radial inner end of the first concave portion of the other straight portion, respectively, radially outward and opposite to each other. An anti-vibration bush characterized by being formed as a third projecting portion projecting into the shape.   3. The portion of the inner cylinder, which is positioned between both ends in the circumferential direction of the one curb portion, and the portion located between both ends in the circumferential direction of the other curb portion are respectively axial directions. Along the radial inner ends of the first concave portion and the second concave portion of the one straight portion, and the diameters of the first concave portion and the second concave portion of the other straight portion. An anti-vibration bush characterized by being formed as a third projecting portion having a shape projecting radially outward and opposite to each other across the inner end of each direction.   5. The prevention according to claim 3, wherein the inner cylinder has a cross-sectional shape as a whole by the first projecting portion, the second projecting portion, and the third projecting portion. Swing bush.

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