JPH10274268A - Anti-vibration bush and bush assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variance in distance between the axial direction opposing surfaces of a flange part in an assembled state and secure stable durability and vibration isolation characteristic by forming an annular recessed part in a cylindrical part of an outer metal fitting being extended continuously to a circumferential direction. SOLUTION: A bush assembly 10 is constructed in such a manner that a channel 16 having inner cylinder metal fittings 18 and 18 securely fixed and an arm eye 14 having external cylinder metal fittings 20 and 20 securely fixed are connected to each other elastically via a rubber elastic body 46 and, based on the elastic deformation action of the rubber elastic body 46, a suspension arm in the arm eye 14 side is connected to a car body in a vibration isolating manner so as to be swung. At this time, a recessed part 40 formed in the external metal fitting 20 is formed to be deeper than a diameter reduced amount by pressfitting or the like of the eternal cylinder metal fitting 20 in a cylinder part 26 such that diameter reduction at the time of pressfitting into the arm eye 14 can be avoided. Also, the cylindrical part 22 of the inner cylinder metal fitting 18 opposite the inner peripheral surface of the recessed part 40 is formed to be a rigid opposing surface extended linearly in an axial direction and thus the generation of an axial direction component force is advantageously prevented via the rubber elastic material 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bush assembly interposed in a motor vehicle such as a suspension connecting portion of a suspension arm to a vehicle body and an anti-vibration bush constituting the bush assembly. The present invention relates to a bush assembly having an improved structure and an anti-vibration bush constituting the bush assembly, which can advantageously obtain both properties.

[0002]

2. Description of the Related Art Conventionally, as one type of a bush assembly interposed in a pivot connecting portion of a suspension arm of an automobile to a vehicle body, for example, as described in Japanese Utility Model Laid-Open No. 2-1244 and the like, An inner cylinder fitting and an outer cylinder fitting each having a cylindrical part and an outward flange formed at one end in the axial direction thereof are arranged at a predetermined distance from each other in the radial direction, and A pair of anti-vibration bushes having a structure in which a rubber elastic body is interposed between the radially opposed surfaces of the respective cylindrical portions and the axially opposite surfaces of the respective flange portions and elastically connected to each other is used. Is inserted from both sides into a cylindrical arm eye formed at the end of the suspension arm, and each outer cylindrical metal fitting is fitted to the arm eye. Between mounting plates Fitted, by both inner tubular member allowed to axially supported between those mounting plate portion, is that so as to vibration damped linkage of Amuai to the attachment plate portion, is known.

[0003] In such a bush assembly, generally, the outer cylinder of each anti-vibration bush is subjected to a reducing action by reducing the diameter of the outer cylindrical fitting before mounting it on the arm eye or reducing the diameter by press-fitting the arm eye. Is added,
Pre-compression is applied to the rubber elastic body interposed between the radially opposing surfaces of the cylindrical portions of the inner and outer cylinders, and a pair of anti-vibration bushes are fitted between the pair of mounting plate portions. By axially tightening the inner cylinder fittings of both anti-vibration bushes between the pair of mounting plates via the pivot inserted through the inner cylinder fitting of the vibration bush, the flanges of the inner and outer cylinder fittings face each other in the axial direction. Precompression is applied to the rubber elastic body interposed between the surfaces. The precompression reduces or prevents the occurrence of tensile stress in the rubber elastic body, improves durability, and imparts the desired vibration damping characteristics.

However, the present inventor has studied that in the conventional bush assembly, even if the vibration-isolating bush alone satisfies the dimensional accuracy, when the vibration-proof bush is assembled to a mounting cylinder member such as an arm eye of a suspension arm, the inner and outer cylinders are not fixed. A large variation easily occurs in the distance between the axially opposed surfaces of the flange portions of the metal fittings, and it has been clarified that this variation is one of the causes of problems relating to the manufacture and performance of the bush assembly. That is, if the distance between the axially opposed surfaces of the flange portions of the inner and outer cylinder fittings is smaller than a design value in a state in which the vibration isolating bush is attached to the mounting cylinder member, the two vibration isolating bushes between the pair of mounting plate portions. Because the axial relative displacement of the flange portion of the inner and outer cylinder fittings when the inner cylinder fittings are tightened in the axial direction is reduced, and it becomes difficult for the pre-compression to the rubber elastic body to be effectively exerted,
The intended durability and anti-vibration characteristics may not be exhibited.On the other hand, when the anti-vibration bush is attached to the mounting cylinder member, the distance between the axially facing surfaces of the flanges of the inner and outer cylinder fittings is the design value. If it is too large, it will be difficult to fit between the pair of mounting plate portions, and there is a possibility that the assembling manufacturability will be significantly deteriorated.

[0005]

Here, the present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide an inner and outer cylinder fitting in a state where it is press-fitted into a mounting cylinder member and assembled. An improved structure that suppresses variations in the distance between the axially opposed surfaces of the flange portion and achieves good assembling manufacturability and stably achieves the intended durability and vibration isolation characteristics. An object of the present invention is to provide a bush assembly and an anti-vibration bush constituting the bush assembly.

[0006]

In order to solve such a problem, the present inventor has made further studies, and found that the flange portions of the inner and outer cylinders are axially opposed to each other when the vibration isolating bush is attached to the mounting cylinder member. It has been newly found that the main cause of the variation in the inter-plane distance is the restriction exerted on the outer metal fitting of the vibration isolating bush. In other words, when the cylindrical portion of the outer cylinder is narrowed and reduced in diameter, the flange that is difficult to reduce in diameter because of its surface rigidity transmits the stress from the cylindrical portion to the flange of the inner cylinder, thereby reducing the diameter. Irregular deformation that is inclined in the direction separating in the axial direction is likely to occur, and the rubber elastic body pre-compressed between the cylindrical parts of the inner and outer cylindrical fittings goes around between the flange parts of the inner and outer cylindrical fittings. Since irregular stress is exerted on the rubber elastic body interposed therebetween and the inner and outer cylinders are easily displaced in the axial direction relatively, the distance between the axially opposed surfaces of the flange portions of the inner and outer cylinders greatly varies. Is easy to occur,
It has been found that the present invention has been completed based on such new findings.

[0007] In order to solve the above-mentioned problems, a feature of the present invention according to claim 1 is that a cylindrical part and an outwardly formed one formed at one axial end of the cylindrical part are provided. The inner and outer cylinders having the flanges are arranged at a predetermined distance from each other in the radial direction, and between the radially opposed surfaces of the cylindrical parts of the inner and outer cylinders and the axis of each flange. It has a structure in which a rubber elastic body is interposed between the direction facing surfaces and elastically connected, and a pair thereof is used,
The outer cylinder fittings are inserted from both sides in the axial direction of the mounting cylinder member so that the outer cylinder fittings are fitted to the mounting cylinder member, and the inner cylinder fittings are disposed between a pair of mounting plate members opposed to each other at a predetermined interval. Is fitted and axially supported by the pair of mounting plate members, thereby forming a bush assembly for connecting the mounting cylinder member and the pair of mounting plate members in a vibration-proof manner. By making the cylindrical portion a small diameter at the axial end portion on the flange portion side, a circumferential direction at a depth equal to or more than the diameter reduction amount exerted upon fitting to the mounting cylindrical member with respect to the cylindrical portion. A continuously extending annular concave portion is formed, and radially inward of the concave portion, extends linearly in the axial direction in the axial cross section, and radially opposed to the concave portion with the rubber elastic body interposed therebetween. Stiffness versus It lies in the provision of the surface.

In the vibration-isolating bush having the structure according to the first aspect of the present invention, the diameter of the outer cylindrical fitting is reduced by reducing the diameter of the bush before mounting it on the mounting cylinder member or press-fitting the mounting cylinder member. The concave portion is applied only to the cylindrical portion where the concave portion is not formed, and the concave portion is interposed between the cylindrical portion where the throttle is applied and the flange portion. In addition, since the concave portion has a bent or curved shape, the transmission of stress from the cylindrical portion to the flange portion during drawing can be advantageously reduced or prevented by the concave portion. In addition, the concave portion is positioned so as to protrude also on the inner peripheral surface side of the cylindrical portion, and by such a concave portion, deformation transmission from between the cylindrical portion of the inner and outer cylindrical fittings of the rubber elastic body to between the flange portions is suppressed. Therefore, the transmission of the deformation stress from the rubber elastic body pre-compressed between the cylindrical portions of the inner and outer cylindrical fittings by the throttle to the rubber elastic body interposed between the flange portions of the inner and outer cylindrical fittings is also performed by the concave portions. This is advantageously reduced or prevented. In addition, since the opposing surface of the concave portion is a rigid opposing surface extending linearly in the axial direction, the concave portion is temporarily deformed, and a compressive force acts on the rubber elastic body between the concave portion and the rigid opposing surface. Even so, the component force for relatively displacing the inner and outer cylindrical fittings in the axial direction can be advantageously suppressed.

Therefore, in such an anti-vibration bush,
By reducing or preventing irregular deformation of the flange portion of the outer cylinder fitting and irregular relative displacement of the inner and outer cylinder fittings in the axial direction due to the drawing of the outer cylinder fitting, the assembling state to the mounting cylinder member is reduced. Variations in the distance between the opposing surfaces of the flanges of the inner and outer cylindrical fittings underneath are advantageously suppressed, thereby facilitating the assembling work by fitting between the pair of mounting plate members when manufacturing the bush assembly. In addition, when the bush assembly is constructed, effective pre-compression is applied to the rubber elastic body interposed between the flange portions of the inner and outer cylinders to obtain stable performance and good durability. It becomes possible.

The rigid opposing surface is advantageously constituted by, for example, the outer peripheral surface of the inner cylindrical metal fitting. In addition, for example, as described in Japanese Utility Model Laid-Open No. 11244/1990,
An intermediate cylindrical metal fitting that is disposed at a predetermined distance from the inner and outer cylindrical metal fittings between the opposing surfaces of the inner and outer cylindrical metal fittings and is adhered in a state of being embedded in the rubber elastic material so as to tune the spring characteristics of the rubber elastic material. It is also possible to provide a rigid opposing surface by the outer peripheral surface of the intermediate cylindrical fitting.

The invention described in claim 2 is the first invention.
In the vibration-isolating bush having the structure according to the invention described in (1), the concave portion has a straight surface extending linearly in the axial direction in the axial cross section on the inner peripheral surface and parallel to the rigid opposing surface. Is characterized.

In the vibration isolating bush having the structure according to the second aspect of the present invention, when the outer cylinder is squeezed, deformation is transmitted from the cylindrical portion of the outer cylinder to the flange, and rubber elasticity is used. The transmission of the deformation stress from between the cylindrical portion of the inner and outer cylindrical fittings to the flange portion of the body is further advantageously reduced or prevented by the concave portion, and the generation of a component force that relatively displaces the inner and outer cylindrical fittings in the axial direction. As a result, the variation in the distance between the opposing surfaces of the flange portions of the inner and outer cylinder fittings in a state of being assembled to the mounting cylinder member can be more effectively suppressed.

[0013] The invention described in claim 3 is the first invention.
Or in the vibration-isolating bush having the structure according to the invention described in 2, wherein the axial length of the recess is not less than 3 mm and not more than 1/3 of the axial length of the outer cylinder. Features.

In the vibration isolating bush having the structure according to the third aspect, as described above, the concave portion has a variation in the distance between the opposing surfaces of the flange portions of the inner and outer cylindrical fittings when assembled to the mounting tubular member. Can be more effectively exerted, thereby improving the workability of assembling the bush assembly and stabilizing the performance and durability more advantageously. When the axial length of the concave portion is smaller than 3 mm, the effect of suppressing the variation in the distance between the facing surfaces of the flange portions of the inner and outer cylindrical fittings in a state of being assembled to the mounting tubular member is likely to be reduced. If the length exceeds one-third of the axial length of the metal fitting, the drawing area of the outer metal fitting becomes small, and it becomes difficult to apply an effective drawing operation to the rubber elastic body.

The invention described in claim 4 is the first invention.
4. The vibration-isolating bush having a structure according to any one of the above aspects, wherein the depth of the concave portion is equal to or less than 1/3 of a radial thickness of the rubber elastic body. .

That is, the concave portion has a shape in which the inner and outer diameters of the cylindrical portion of the outer cylindrical member are both reduced, and setting the depth to be deeper is equivalent to the cylindrical portion when drawing the outer cylindrical member. It is effective for suppressing deformation transmission from the cylindrical part of the inner and outer cylindrical metal fittings to the flange part in the rubber elastic body, etc. There is a possibility that the anti-vibration characteristics and elastic characteristics of the anti-vibration bush are adversely affected. Therefore, according to the fourth aspect of the present invention, if the depth of the recess is set to 1/3 or less of the radial thickness of the rubber elastic body, the adverse effect on the vibration-proof characteristics of the rubber elastic body is advantageously suppressed. Can be

The invention described in claim 5 is the first invention.
In the vibration-isolating bush having the structure according to any one of claims 1 to 4, the surface of the flange portion of the inner cylindrical metal member facing the flange portion of the outer cylindrical metal member,
It is characterized in that it is an inclined surface that is separated from the outer cylinder in the axial direction as it goes radially outward.

In the vibration isolating bush having the structure according to the fifth aspect of the present invention, even when the deformation stress is transmitted from between the cylindrical portions of the inner and outer cylindrical fittings of the rubber elastic body to between the flange portions, Since the deformation stress is advantageously released in the radial direction along the inclined surface of the flange portion in the inner cylinder, the variation in the distance between the facing surfaces of the flanges of the inner and outer cylinders in a state of being assembled to the mounting cylinder member. It can be suppressed more effectively.

According to a sixth aspect of the present invention, there is provided an anti-vibration bush having a structure according to any one of the first to fifth aspects, wherein the bush is inserted from both axial sides of the mounting tubular member. In a state where the outer tube fittings are fitted to the mounting tube members, the flange portions of the two outer tube members are overlapped on the axial end surfaces of the mounting tube members, and the axial direction of the both outer tube members is The axial length of the outer cylinder is set so that a gap is formed between the facing surfaces.

In the vibration isolating bush having the structure according to the sixth aspect of the present invention, the rubber elastic body in forming the bush assembly due to the dimensional change accompanying the drawing of the outer cylinder is reduced. Variations in the amount of compression are also advantageously reduced or prevented.

The invention described in claim 7 is the first invention.
6. In the vibration-isolating bush having a structure according to any one of claims 6 to 6, in a state where the outer cylinder fittings are inserted from both axial sides of the mounting cylinder member and fitted to the mounting cylinder member, When a gap is formed between the axially opposed surfaces of the two inner cylinders, and when the two inner cylinders are fitted between the pair of mounting plate members and axially supported, the pair of mounting plate members The axial length of the inner cylindrical fitting is set such that the axially opposed surfaces of the two inner cylindrical fittings are fastened in the axial direction between the two and are brought into contact with each other.

In the vibration-isolating bush having the structure according to the seventh aspect of the present invention, the amount of axial pre-compression exerted on the rubber elastic body when forming the bush assembly can be advantageously secured. Since the inner cylindrical fittings are brought into contact with each other, the axial pre-compression amount exerted on the rubber elastic body can be set stably.

Further, in order to solve the above-mentioned problems, the invention according to claim 8 includes a cylindrical portion and an outward flange formed at one axial end of the cylindrical portion. The inner cylindrical fitting and the outer cylindrical fitting are arranged at a predetermined distance from each other in the radial direction, and rubber is provided between the radially facing surfaces of the cylindrical portions of the inner and outer cylindrical fittings and the axially facing surfaces of the flange portions. After using a pair of vibration-isolating bushes having a structure in which an elastic body is interposed and elastically connected, the pair of vibration-isolating bushes is subjected to drawing processing on the cylindrical portion of the outer cylindrical metal fitting, and then the mounting cylinder is mounted. Along with fitting the outer cylinder fittings to the mounting cylinder member by press-fitting from both axial sides of the member, fitting the inner cylinder fittings between a pair of mounting plate members opposed at a predetermined interval, Tighten in the axial direction and support with the pair of mounting plate members With this, in the bush assembly for connecting the mounting cylinder member and the pair of mounting plate members in a vibration-proof manner, the cylindrical portion of the outer cylinder fitting in each of the vibration-proofing bushes is located at an axial end on the flange portion side. By having a small diameter, while forming an annular concave portion extending continuously in the circumferential direction at a depth equal to or greater than the diameter reduction amount exerted upon press-fitting the cylindrical portion with the drawing process and the mounting cylindrical member, A radially inner surface of the concave portion is provided with a rigid opposing surface that extends linearly in the axial direction in an axial cross section and is positioned radially opposite to the concave portion with the rubber elastic body interposed therebetween. And

In the bush assembly having the structure according to the eighth aspect, the pair of vibration-isolating bushes constituting the bushing assembly is the same as the vibration-isolating bush having the structure according to the first aspect. The transmission of stress from the cylindrical portion to the flange portion at the time of drawing, and the transmission of deformation from between the cylindrical portion of the inner and outer cylindrical fittings to between the flange portions of the rubber elastic body are advantageously reduced or reduced by the concave portion formed in the outer cylindrical fitting. Is prevented, the variation in the distance between the opposing surfaces of the flange portions of the outer cylinder fittings can be effectively suppressed under a state in which such a pair of vibration isolating bushes is mounted on the mounting cylinder member, and thereby, In addition, the workability when assembling with a pair of mounting plate members pivotally supported is advantageously secured, and the pre-compression is advantageously applied to the rubber elastic body of each anti-vibration bush when assembled. Good Naru vibration damping performance and durability Te is as it can be realized stably.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows an embodiment of the present invention in which a suspension arm of a rear wheel suspension system of an automobile is interposed in a pivotally connecting portion of the suspension arm with respect to the vehicle body, and the suspension arm is swung with respect to the vehicle body. A bushing assembly 10 with a possible anti-vibration connection is shown. The bush assembly 10 includes an arm eye 14 as a mounting cylinder member in which a pair of vibration isolating bushes 12 and 12 are integrally formed at an axial end of a suspension arm (not shown), and a mounting plate fixed to a vehicle body (not shown). The arm eye 14 is interposed between the channel 16 as a member, and is connected to the channel 16 so as to be swingable about one axis.

More specifically, each of the pair of vibration isolating bushes 12 has the same structure as shown in FIG. The anti-vibration bush 12 has an inner cylinder fitting 18 and an outer cylinder fitting 20. Inner tube fitting 18
Is composed of a thick cylindrical portion 22 and a flange portion 24 that extends radially outward from one axial end of the cylindrical portion 22. Similarly, the outer tube fitting 20 also includes a cylindrical tube portion 26 and a flange portion 28 that extends radially outward from one axial end of the tube portion 26. Here, the outer tube fitting 20 is connected to the inner tube fitting 18.
The cylindrical portion 26 has a predetermined size and a larger diameter than the cylindrical portion 22 of the inner cylindrical metal fitting 18 and has a shorter axial length than the cylindrical portion 26. Hardware 18
Are arranged on the same axis at a predetermined distance outward in the radial direction.

The flange 24 of the inner cylinder 18 and the flange 28 of the outer cylinder 20 are positioned on the same side in the axial direction, and the outer cylinder 20 is connected to the inner cylinder 18.
The axial end face 32 of the outer cylinder 20 opposite to the flange 28 is disposed so as to be biased toward the axial end opposite to the flange 24. It is located slightly axially inward of the opposite axial end face 34. As a result, the flange portions 24, 28 of the inner and outer tube fittings 18, 20 are opposed to each other at a predetermined distance: L1 in the axial direction.

The facing surface (axial inner side surface) 30 of the flange portion 24 of the inner cylindrical member 18 has an inclined surface which is gradually separated in the axial direction from the flange portion 28 of the outer cylindrical member 20 as going outward in the radial direction. Have been. The axial end face 36 of the inner tube fitting 18 on the flange portion 24 side has a central portion formed into a ring-shaped serration to form a crimping surface. Furthermore,
The outer peripheral surface of the inner cylindrical member 18 at the axial end opposite to the flange portion 24 of the cylindrical portion 22 is formed into a circumferentially concave groove-shaped curved concave surface 38 slightly concave with a smooth curved surface.

On the other hand, the outer cylindrical fitting 20 has a small inner and outer diameter over a predetermined length at the axial end of the cylindrical portion 26 on the flange 28 side, and is continuously formed in the circumferential direction. An extended annular or cylindrical concave portion 40 is formed. The concave portion 40 is formed including the inner peripheral edge of the flange portion 28. In particular, in this embodiment,
An inner peripheral surface of a central portion in the axial direction of the concave portion 40 has a straight surface 42 linearly extending in the axial direction over a predetermined length in the axial direction.
It has been.

The surface facing the concave portion 40 of the outer cylindrical member 20 inward in the radial direction is constituted by the outer peripheral surface of the cylindrical portion 22 of the inner cylindrical member 18 which is a rigid member. , A rigid opposing surface 44 that extends linearly in the axial direction. In short, the rigid opposing surface 4
Reference numeral 4 denotes a cylindrical surface that extends in the circumferential direction around the central axis of the concave portion 40 of the outer cylindrical member 20, and is opposed to the inner peripheral surface of the concave portion 40 at a predetermined distance in the radial direction. -ing The rigid opposing surface 44 is parallel to the straight surface 42 on the inner peripheral surface of the concave portion 40 of the outer cylinder 20.

The rubber elastic body 4 is provided between the inner cylindrical fitting 18 and the outer cylindrical fitting 20 which are arranged at a predetermined distance in the radial direction.
6 are interposed. The outer peripheral surface of the cylindrical portion 22 of the inner cylindrical member 18, the axial inner surface of the flange portion 24, and the inner peripheral surface of the cylindrical portion 26 of the outer cylindrical member 20 and the axis of the flange portion 28 with respect to the rubber elastic body 46. The outer surfaces in the directions are integrally vulcanized molded products which are respectively vulcanized and bonded. In short, the rubber elastic body 46 has a thick and substantially cylindrical shape as a whole, and is provided between the inner and outer cylindrical fittings 18 and 20 and between the radially opposed surfaces of the cylindrical portions 22 and 26. It is configured to include an annular block portion 48 and an annular block portion 50 interposed between the axially opposed surfaces of the flange portions 24 and 28.

After vulcanization molding of the rubber elastic body 46,
If necessary, as shown by an arrow in FIG. 2, the cylindrical portion 26 of the outer metal fitting 20 is reduced in diameter by octagonal drawing or the like, so that the tensile stress of the rubber elastic body 46 is reduced. The precompression will be applied. The cylindrical portion 26
Is applied to the region excluding the concave portion 40, and is preferably applied over the entire region of the tubular portion 26 excluding the concave portion 40.

As shown in FIG. 3, the pair of anti-vibration bushes 12, 12, each having the above-described structure, is configured such that each outer cylinder 20
At the end in the axial direction opposite to the flange portion 28, the arm eye 14 is inserted and assembled by being press-fitted from both sides in the axial direction. Here, the outer tube fitting 20
In the cylindrical portion 26, a press-fitting portion for the arm eye 14 is formed as a whole except for the concave portion 40. Also,
Each anti-vibration bush 12 is provided with a flange portion 28 of the outer cylinder fitting 20.
When the inner surface of the outer cylinder abuts on the axial end surface of the arm eye 14, the insertion end with respect to the arm eye 14 is positioned. The axial length of the outer cylindrical member 20 is set in consideration of the axial length of the arm eye 14 so that a slight gap is formed between the outer and upper ends of the arm eye 14.

Further, such a pair of anti-vibration bushes 1
Under the state of being assembled to the arm eyes 14, a slight gap is formed between the axial end surfaces 34, 34 of the inner cylindrical fittings 18, 18. 18, the distance between the axial end surfaces 36, 36 on the flange portion 24 side, in other words, the arm eye 14
The maximum axial dimension L2 of the pair of anti-vibration bushes 12, 12 attached to the arm 16 is substantially equal to the dimension between the opposing surfaces of the pair of mounting plate portions 52, 52 in the channel 16 to which the arm eye 14 is connected. Preferably, the axial length of the inner cylindrical member 18 is set in consideration of the dimensions of the channel 16 and the like so as to be slightly smaller than the distance between the facing surfaces of the pair of mounting plate portions 52, 52.

The axial end face 5 of the rubber elastic body 46 constituting the vibration isolating bush 12 on the side of the cylindrical block portion 48 is provided.
Numeral 4 is depressed inward in the axial direction with a curved surface shape.
An annular space 56 that allows elastic deformation of the rubber elastic body 46 is formed between the opposing surfaces 6. Also,
At the axial end of the rubber elastic body 46 on the side of the cylindrical block portion 48, the curved concave surface 38 formed on the outer peripheral surface of the cylindrical portion 22 of the inner cylindrical fitting 18 increases the bonding area and the free area. I have.

The pair of anti-vibration bushes 12, 12 assembled to the arm eye 14 in this manner is further inserted into a channel 16 as shown in FIG. Two vibration-isolating bushes 12, 12 are arranged in a state of being arranged in series so as to straddle a pair of mounting plate portions 52, 52 which are opposed to each other. Then, the support bolts 60, which are inserted through the support holes 58, 58 formed through the mounting plate portions 52, 52 of the channel 16 and straddle the mounting plate portions 52, 52, are prevented. By being inserted into the inner hole 62 of the vibration bushes 12, 12, the vibration isolation bushes 12, 1 are inserted.
2 is supported on the channel 16 via a support bolt 60.

Further, the support bolts 60 inserted through the inner cylindrical fittings 18, 18 of the vibration isolating bushes 12, 12 are tightened up, and the mounting plate portions 52, 52 of the channel 16 are deformed in a direction approaching each other. By this, the inner cylinder fitting 1
Axial clamping forces are exerted on 8,18. Due to this tightening force, the inner cylindrical fittings 18, 18 are relatively displaced in a direction approaching in the axial direction against the elastic force of the rubber elastic body 46, and the axially facing surfaces 34, 34 abut against each other. And the serrated portion on the axially outer surface 36 of both inner cylindrical fittings 18
Is pressed against the contact surface of the mounting plate portion 52.

That is, in the bush assembly 10 assembled as described above, the channel 16 to which the inner cylindrical fittings 18 and 18 are fixed and the arm eye 14 to which the outer cylindrical fittings 20 and 20 are fixed are formed by rubber elasticity. The suspension arm on the arm eye 14 side is swingably connected to the vehicle body on the channel 16 side in an anti-vibration manner by the elastic deformation of the rubber elastic body 46. It will be.

In this case, the cylindrical portion 26 of the outer metal fitting 20 is formed.
The diameter is reduced by a drawing process performed prior to the press-fitting into the arm eye 14 or a press-fitting operation into the arm eye 14, whereby an effective preload is applied to the cylindrical block portion 48 of the rubber elastic body 46. Compression is applied, but the drawing and press-fitting operations are performed exclusively by the outer cylinder fitting 2
This process is performed on the portion of the cylindrical portion 26 except for the concave portion 40. Therefore, the transmission of stress to the flange portion 28 due to the diameter reduction of the cylindrical portion 26 of the outer cylindrical fitting 20 is effectively performed by the concave portion 40 interposed between the cylindrical portion 26 and the flange portion 28. This can be reduced or prevented, and irregular deformation of the flange portion 28 can be suppressed.

Moreover, the concave portion 40 provided in the cylindrical portion 26 of the outer cylindrical fitting 20 projects radially inward,
A rigid opposing surface 44 radially opposing the concave portion 40 is formed linearly in the axial direction, and can effectively exert an axial restraining force on the rubber elastic body 46. Compression deformation of the annular block portion 5 generated in the cylindrical block portion 48 due to drawing and press-fitting operations on the portion 26
Transmission to zero is effectively reduced or prevented by the recess 40. Therefore, irregular stress change or deformation in the annular block portion 50 due to drawing or press-fitting operation on the cylindrical portion 26 can be effectively suppressed. In particular, in the present embodiment, since the facing surface of the concave portion 40 with respect to the rigid facing surface 44 has a straight surface that extends in parallel with the rigid facing surface 44, the axial restraining force on the rubber elastic body 46 is further reduced. It will be effective.

In particular, the cylindrical portion 22 of the inner cylindrical member 18 opposed to the inner peripheral surface of the concave portion 40 of the outer cylindrical member 20 is formed as a rigid opposing surface 44 having a cylindrical surface extending linearly in the axial direction. Accordingly, even if the diameter-reducing deformation of the cylindrical portion 26 of the outer cylindrical fitting 20 is applied to the concave portion 40, the action of the radial compressive force via the rubber elastic body 46 (the cylindrical block portion 48). The generation of the axial component force due to the deformation can be advantageously avoided, and the inner and outer cylindrical metal fittings 1 due to the deformation of the concave portion 40 can be prevented.
The axial relative displacement of 8, 20 can also be effectively prevented. That is, for example, when the rigid opposing surface 44 has a tapered cylindrical surface shape inclined in the axial direction, the radial compressive force applied to the rubber elastic body 46 when the concave portion 40 is subjected to the diameter reduction deformation. By generating an axial component force at a ratio corresponding to the inclination angle of the rigid opposing surface 44, there is a possibility that the axial component force exerts an axial relative displacement force between the inner and outer tube fittings 18 and 20. As described above, since the rigid opposing surface 44 has a cylindrical shape, even when the concave portion 40 is subjected to the diameter reduction deformation, the stress or the like caused by the diameter reduction compressive deformation in the cylindrical block portion 48 in the radial direction. And the like, and are advantageously absorbed by the inner and outer cylindrical fittings 18, 20.
In this case, the relative displacement in the axial direction and the irregular stress change and deformation in the annular block portion 50 can be extremely effectively avoided.

Accordingly, in the vibration isolating bush 12 having the above-described structure, even when the bushing is assembled to the arm eye 14, the flange portions 2 of the inner and outer cylindrical fittings 18, 20 are formed.
Axial end faces of the inner cylindrical fittings 18, 18 on the flange portion 24 side when assembled to the arm eye 14 while effectively preventing variations in the size of the axially opposed surfaces 4 and 28: L1. Distance between 36, 36 (maximum axial dimension): L
2 will be advantageously maintained at the predetermined design value. As a result, the anti-vibration bush 1 attached to the arm eye 14
2 and 12 can be easily inserted and attached to the channel 16, and the effective pre-compression is exerted on the annular block portions 50 of the respective vibration-isolating bushes 12 and 12 by tightening the support bolts 60. In addition, it is possible to stably obtain the intended anti-vibration performance and durability.

As is apparent from the above description, the concave portion 40 of the outer cylindrical member 20 is press-fitted in the cylindrical portion 26 of the outer cylindrical member 20 so that the diameter of the arm member 14 during press-fitting is avoided. It is formed with a depth dimension: D larger than the diameter reduction amount due to the above. On the other hand, recess 4
If the depth of 0 is too large, the height of the concave portion 40 protruding inward in the radial direction of the outer cylindrical member 20 becomes large, so that the thickness of the rubber elastic body 46 is reduced, which has an adverse effect on vibration damping characteristics. Therefore, it is preferable that the depth D of the concave portion 40 be set to 1/3 or less of the radial thickness T of the rubber elastic body 46.

The axial length L3 of the concave portion 40 is the distance L1 between the axially facing surfaces of the flange portions 24, 28 of the inner and outer metal fittings 18, 20 in the state of being assembled to the arm eye 14 as described above. In order to more effectively obtain the effect of suppressing the variation in the size, it is desirable to be 3 mm or more. However, if it is too long, it becomes difficult to exert an effective pre-compression on the cylindrical block portion 48. It is desirable to set the axial length of the outer tube fitting 20 to 1/3 or less of L4 or to 1/3 or less of the axial length of the cylindrical block portion 48 of the rubber elastic body 46.

Further, the bush assembly 10 of the present embodiment
, The facing surface 3 of the flange portion 24 of the inner cylinder fitting 18
Since 0 is an inclined surface, the internal stress of the annular block portion 50 when the anti-vibration bushes 12 and 12 are attached to the arm eye 14 as shown in FIG.
It is advantageously released radially outward, and the relative displacement of the inner and outer cylindrical fittings 18, 20 in the axial direction caused by the internal stress is further advantageously reduced. Inner and outer tube fittings 1 in the assembled state
The effect of suppressing the variation in the size of the distance L1 between the axially opposed surfaces of the flange portions 24 and 28 of the flanges 8 and 20 is more advantageously exerted.

Further, in the bush assembly 10 of the present embodiment, the shafts of the inner cylindrical fittings 18, 18 which are spaced apart and opposed to each other when the vibration isolating bushes 12, 12 are attached to the arm eyes 14. Direction end surfaces 34, 34
When the channel 16 is attached to the inner and outer cylindrical fittings 18, 2
0 is positioned relatively stably in the axial direction, and the distance between the axially opposed surfaces of the flange portions 24, 28 of the inner and outer cylindrical fittings 18, 20 in the state of being attached to the channel 16 is further stabilized. Thus, the pre-compression is more stably applied to the annular block portion 50 interposed therebetween.

The embodiment of the present invention has been described above in detail, but this is merely an example.
It is not to be construed that the invention is limited only to such specific examples.

For example, in order to adjust the spring characteristics of the vibration isolating bush 12, a hollow portion or a hollow portion extending continuously or in a predetermined length in the circumferential direction may be formed in the rubber elastic body 46. It is possible. Also, an intermediate cylindrical metal member extending continuously in the circumferential direction between the opposing surfaces of the inner cylindrical metal member 18 and the outer cylindrical metal member 20 or an intermediate plate metal member extending a predetermined length in the circumferential direction is provided so that the rubber elastic body 46 is provided. It is also possible to embed and fix it. In the case where an intermediate cylindrical member or the like is disposed radially inward of the concave portion 40 of the inner cylindrical member 18, a rigid opposing surface is formed by the intermediate cylindrical member or the like which is positioned radially opposite to the concave portion 40. Is formed.

It is not always necessary to form a straight portion extending in the axial direction in the concave portion 40, and a concave portion having no straight portion protruding with a chevron section curved inward in the radial direction can be employed. It is.

Further, it is also possible to adopt a press-formed product or the like as the inner cylindrical member 18 as in the case of the outer cylindrical member 20 or, conversely, to use the die as the outer cylindrical member 20 in the same manner as the inner cylindrical member 18. It is also possible to adopt a cast product or a machined product.

In addition, in the previous embodiment, a specific example in which the present invention is applied to an anti-vibration connecting member for a vehicle body of a suspension arm of an automobile is shown. Needless to say, it can be widely applied to an interposed elastic connector or the like.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, the present invention can be implemented in a form in which various changes, modifications, improvements, and the like are made.
It goes without saying that all such embodiments are included within the scope of the present invention, without departing from the spirit of the present invention.

[0054]

As is clear from the above description, in the vibration-isolating bush having the structure according to the first to seventh aspects of the present invention, any of the inner and outer cylinders can be mounted even when assembled to the mounting cylinder member. Variations in the distance between the axially facing surfaces of the flange portion of the bracket are effectively suppressed,
As a result, the workability of mounting the pair of vibration isolating bushes assembled to the mounting cylinder member to the mounting plate member is improved, and
By applying effective pre-compression to the rubber elastic body of the vibration isolating bush, it is possible to stably obtain the target vibration isolating performance and durability.

Further, in the bush assembly having the structure according to the eighth aspect of the present invention, in each of the vibration-isolating bushes due to the drawing process in the outer cylinder fitting of the vibration-isolating bush or the diameter reduction by press-fitting into the mounting cylinder member. By effectively suppressing the change in the distance between the axially opposed surfaces of the inner and outer cylinders, the distance between the axially opposite ends of both inner cylinders of the pair of anti-vibration bushes when assembled to the mounting cylinder member is predetermined. As a result, the pair of anti-vibration bushes assembled to the mounting cylinder member can be easily fitted and mounted to the pair of mounting plate members, and both inner cylinders can be mounted. By tightening the bracket in the axial direction, effective pre-compression is exerted on the rubber elastic body of each vibration-isolating bush, so that the desired vibration-isolating performance and durability can be stably obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view showing a bush assembly as one embodiment of the present invention.

FIG. 2 is an explanatory longitudinal sectional view showing an anti-vibration bush constituting the bush assembly shown in FIG. 1;

FIG. 3 is an explanatory longitudinal sectional view showing a state in which the anti-vibration bush shown in FIG. 2 is pressed into an arm eye.

[Explanation of symbols]

 Reference Signs List 10 bush assembly 12 anti-vibration bush 14 arm eye 16 channel 18 inner cylinder 20 outer cylinder 22 cylindrical part 24 flange part 26 cylindrical part 28 flange part 44 rigid opposing surface 46 rubber elastic body 52 mounting plate part 60 support bolt

Claims (8)

[Claims] 1. An inner cylindrical fitting and an outer cylindrical fitting each having a cylindrical portion and an outward flange formed at one axial end of the cylindrical portion are spaced apart from each other in a radial direction by a predetermined distance. A rubber elastic body is interposed between the radially opposed surfaces of the cylindrical portions of the inner and outer cylindrical fittings and between the axially opposed surfaces of the flange portions, and the inner and outer cylindrical fittings are elastically connected to each other. Is used, and the outer cylinder fittings are inserted from both sides in the axial direction of the mounting cylinder member so as to be fitted to the mounting cylinder member, and between a pair of mounting plate members opposed to each other at a predetermined interval. An anti-vibration bush comprising a bush assembly which is fitted into the inner cylinder fittings and is pivotally supported by the pair of mounting plate members, thereby connecting the mounting cylinder members and the pair of mounting plate members in a vibration-proof manner. The cylindrical portion of the outer tube fitting, By making the diameter smaller at the axial end portion on the flange portion side, an annular ring extending continuously in the circumferential direction at a depth equal to or greater than the diameter reduction amount exerted upon fitting the cylindrical portion to the mounting cylinder member. And a rigid opposing surface that extends linearly in the axial direction in the axial cross section radially inward of the concave portion, and that is radially opposed to the concave portion with the rubber elastic body interposed therebetween. An anti-vibration bush characterized by having a. 2. The anti-vibration device according to claim 1, wherein the concave portion has a straight surface that extends linearly in the axial direction in the axial cross section on the inner peripheral surface and is parallel to the rigid opposing surface. bush. 3. The anti-vibration bush according to claim 1, wherein the axial length of the recess is not less than 3 mm and not more than 1/3 of the axial length of the outer cylinder. 4. The anti-vibration bush according to claim 1, wherein a depth of the concave portion is equal to or less than 1/3 of a radial thickness of the rubber elastic body. 5. An opposite surface of the flange portion of the inner cylindrical member to the flange portion of the outer cylindrical member,
The anti-vibration bush according to any one of claims 1 to 4, wherein the inclined surface is an inclined surface that is separated from the outer cylinder in the axial direction as it goes radially outward. 6. In a state in which the outer cylinder fittings are inserted from both sides in the axial direction of the mounting cylinder member and the both outer cylinder fittings are fitted to the mounting cylinder member, the flange portions of the both outer cylinder fittings are attached to the mounting cylinder. The axial length of the outer cylinder is set so that the outer cylinder is overlapped on the axial end surface of the member and a gap is formed between the axially opposed surfaces of the outer cylinders. The vibration isolating bush according to any one of the above. 7. A gap is formed between the axially opposed surfaces of the inner cylinders in a state where the outer cylinders are inserted from both sides in the axial direction of the mounting cylinder and the outer cylinders are fitted to the mounting cylinder. On the other hand, when the two inner cylindrical fittings are fitted between the pair of mounting plate members and are axially supported, the two inner cylindrical fittings are tightened in the axial direction between the pair of mounting plate members. The anti-vibration bush according to any one of claims 1 to 6, wherein the axial length of the inner cylindrical member is set so that the axially opposed surfaces are brought into contact with each other. 8. An inner cylindrical fitting and an outer cylindrical fitting each having a cylindrical part and an outward flange formed at one axial end of the cylindrical part are spaced apart from each other by a predetermined distance in the radial direction. A pair of anti-vibration bushes having a structure in which a rubber elastic body is interposed between the radially opposed surfaces of the cylindrical portions of the inner and outer cylindrical fittings and between the axially opposed surfaces of the flange portions and elastically connected. After subjecting such a pair of vibration-isolating bushes to a drawing process on the cylindrical portion of the outer cylindrical member, the two outer cylindrical members are press-fitted from both axial sides of the mounting cylindrical member so that the outer cylindrical members are attached to the mounting cylindrical member. The two inner cylinder fittings are fitted between a pair of mounting plate members facing each other at a preset interval, and are tightened in the axial direction to be axially supported by the pair of mounting plate members. A bracket for vibration-proof connecting the mounting cylinder member and the pair of mounting plate members. In the shroud assembly, the cylindrical portion of the outer cylindrical fitting in each of the vibration-isolating bushes has a small diameter at an axial end portion on the flange portion side. An annular concave portion extending continuously in the circumferential direction at a depth equal to or greater than the diameter reduction amount exerted upon press-fitting into the mounting cylinder member is formed, and radially inward of the concave portion is linear in the axial direction in the axial cross section. A bushing assembly provided with a rigid opposing surface which extends in the radial direction and is radially opposed to the recess with the rubber elastic body interposed therebetween.