JP2000161434A - Vibration proof bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy a required spring characteristic by integrally forming an inner cylinder flange with an axial outer end of the inner cylinder, integrally forming an outer cylinder flange at a position axially inner than the inner flange at an axial end of an outer cylinder, and vulcanization bonding flange rubber part made of rubber elastic body to between the inner and outer flanges. SOLUTION: Around the whole circumference of an axial outer end of an inner cylinder 11, an inner cylinder flange 17 rising in an orthogonal manner to an axis is integrally formed. An outer cylinder flange 18 rising in the orthogonal manner to the axis is openwise formed on a position axially inner than the inner flange 17 at an axially outer end of an outer flange 12. A rubber elastic body 13 is interposed between the inner and outer cylinders 11, 12 to vulcanization bond the two 11, 12 to each other, and also is interposed between the inner and outer flanges 17, 18 to vulcanization bond the two 17, 18 to thereby form a flange rubber part 20. With this constitution, by the existence of the flanges 17, 18 and the flange rubber part 20, the rigidity of spring in the forward and rearward direction can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration bush used for a steering rack housing or the like.

[0002]

2. Description of the Related Art It is known that a shear-type anti-vibration bush in which a rubber-like elastic body is vulcanized and bonded between an inner and an outer cylinder is used for a rack housing of a steering mechanism of an automobile and has a vibration insulating function. I have. This anti-vibration bush
If the inner and outer cylinders are aligned with the front and rear axes of the vehicle, they must be soft in the left and right directions and hard in the up and down directions and the front and rear directions to affect the steering response and steering stability. ing.

[0003] As a conventional anti-vibration bush, there are a conventional anti-vibration bush shown in Figs.
Is known. FIG. 8 is a cross-sectional view of the vibration-isolating bush 100 of Conventional Example 1, and FIG. In each case, the upper side from the axial center of the inner cylinder 101 (indicated by a dashed line in the figure) shows a vertical section cut in the vertical direction, and the lower side shows a horizontal section cut in the horizontal direction.

[0004] The vibration-isolating bush 100 of the conventional example 1 has an inner cylinder 1
The rubber-like elastic body 102 is vulcanized and adhered to the periphery of the rubber member 101. The rubber-like elastic body 102 is provided at both ends in the axial direction via a main body rubber portion 102a at a central portion in the axial direction and ring-shaped concave grooves 102b on both sides thereof. Are formed on the left and right sides of the main body rubber portion 102a.
A recess 103 for forming a hollow portion is formed.

The anti-vibration bush 100 is press-fitted into the connecting cylinder 104 of the rack housing, and the rubber-like elastic
The two flange rubber portions 102c sandwich both axial ends of the outer cylinder.

FIG. 10 is an exploded view of a vibration-isolating bush of Conventional Example 2, and FIG. 11 is a sectional view showing a state where the vibration-isolating bush is attached to a steering rack housing or the like. Both are inner cylinders 10
The upper side from the center of one axis (dashed line in the drawing) is a vertical section cut in the vertical direction, and the lower side is a horizontal section cut in the horizontal direction.

The vibration isolating bush 100 of the conventional example 2 has an inner cylinder 1
A rubber-like elastic body 102 is vulcanized and adhered to the periphery of the inner cylinder 101, and side bushes 105 are press-fitted at both axial ends of the inner cylinder 101. A flange rubber 107 is vulcanized and bonded to the inner side in the axial direction of a ring-shaped support plate 106 having a central boss portion 106a.
07 is vulcanized and bonded to the outer surface of the central boss portion 106a.
01 so that both ends in the axial direction of the connecting cylinder 104 are sandwiched.

[0008]

By the way, with respect to the conventional example 1 and the conventional example 2, it was examined whether or not the required characteristics of the vibration isolating bush in the steering mechanism were satisfied.

[0009]

[Table 1]

As shown in Table 1, in Conventional Example 1, the spring characteristics in the horizontal direction and the vertical direction in the direction perpendicular to the axis can be set to desired values by changing the size and shape of the rubber-like elastic body. Is a shear-type anti-vibration bush, so if external force acts in the front-rear direction, even if there are flange rubber parts at both axial ends of the outer cylinder, the front-rear direction (axial direction)
The spring stiffness becomes relatively softer than in the direction perpendicular to the axis, and the desired characteristics are not satisfied. In particular, if the spring stiffness in the front-rear direction is low, part of the input escapes in the front-rear direction at the time of input from the left-right direction, so that steering response is deteriorated and chatter phenomenon occurs in the rack housing. There was a disadvantage that the vibration insulation was impaired.

On the other hand, in Conventional Example 2, as shown in Table 1, the side bushes 105 are disposed on both sides in the axial direction, so that the spring rigidity in the front-rear direction is improved, but the side bushes are assembled in a later step. Because it has a three-piece structure,
There was a problem that the assembly cost and the rubber vulcanization mold cost were high. Also, the boss 1 of the side bush 105
Since the flange rubber 107 is also vulcanized and bonded to 05a, this rubber part is involved in input in the left-right direction, and the hysteresis loss in the left-right direction is increased. . Further, between the side bush 105 and the connecting cylinder 104 of the housing,
There was a problem that a stick-slip noise was generated when an external force was input.

[0012]

The inventor of the present invention has made intensive studies to solve the problems of the prior art examples 1 and 2, and as a result, an inner cylinder flange that rises in the direction perpendicular to the axis is integrally formed at the axially outer end of the inner cylinder. The outer cylinder flange is formed integrally at the axially outer end of the outer cylinder and rises in the direction perpendicular to the axis axially inward of the inner cylinder flange, and a flange rubber portion of a rubber-like elastic body is added between the inner and outer cylinder flanges. Adopted the structure of sulfur bonding.

By adopting the above configuration, not only the spring rigidity in the front-rear direction (axial direction) can be hardened due to the presence of the inner and outer cylinder flanges and the flange rubber portion, but also the conventional example 2 because of the outer cylinder adhesion type. It has been found that assembling costs and vulcanizing mold costs can be reduced and stick-slip can be eliminated.

Since the inner and outer cylinder flanges are of a type in which the flange rubber is vulcanized and bonded between them, in consideration of assembly to a bush mounting member such as a housing, it is presumed that the inner and outer cylinders are arranged on one side in the axial direction of the inner and outer cylinders. However, the axial length of the inner and outer cylinders can be appropriately selected by a bush mounting member such as a housing to be assembled, and a one-piece structure vibration isolator corresponding to the axial length of the connecting cylinder of the housing, or coupling of the housing. Any of the two-piece vibration-isolating devices in which the anti-vibration bushes having a length equal to half the axial length of the cylinder are arranged with their inner ends facing each other may be employed.

The diameter of the inner and outer cylinder flanges in the direction perpendicular to the axis is
It can be selected as appropriate according to the spring characteristics required for the anti-vibration bush, but by adjusting the flange diameter, the spring stiffness in the front-rear direction can be adjusted without substantially affecting the spring stiffness in the vertical and horizontal directions perpendicular to the axis. It is possible to do.

Further, the anti-vibration bush can be applied irrespective of the presence or absence of a bulge. However, when the spring rigidity in the left-right direction in the direction perpendicular to the axis is set to be soft, the inner cylinder of the rubber-like elastic body is sandwiched. It is only necessary to form a bulge on the left and right sides in the direction perpendicular to the axis and open to the inner end face in the axial direction, and the length of the bulge in the axial direction can be appropriately set.

Such an anti-vibration bush can be used for various connecting parts of an automobile. In particular, in a rack and pinion type steering mechanism, if it is used as an anti-vibration bush for supporting a rack housing in an anti-vibration manner, This is an effective means for satisfying the required spring characteristics in the front-rear direction and the vertical and horizontal directions. In particular, when the anti-vibration bush is arranged and used with the vehicle front-rear direction being the axial direction, the spring rigidity in the front-rear direction is also hard. Also, if the bulge is formed longer than the axial length of the connecting cylinder of the rack housing,
Since the hysteresis loss in the left-right direction can be reduced, the steering responsiveness can be improved by the synergistic action in addition to the increase in the spring rigidity in the front-rear direction.

[0018]

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

[First Embodiment] FIG. 1 is a view showing a part of a steering mechanism according to a first embodiment, FIG. 2 is a sectional view showing a two-piece vibration isolator, and FIG. FIG. 4 is a sectional view taken along line AA of FIG.

As shown in FIG. 1, a vibration isolator 1 according to the present embodiment includes a rack and pinion type steering mechanism 2.
, The rack housing 3 for accommodating the rack is supported on the sub-frame of the suspension member in a vibration-proof manner.

The steering mechanism 2 connects the left and right tie rods 6 with one rack (not shown), and meshes this rack with a pinion (not shown) of the steering shaft 7.
The structure is such that the torque applied to the handle is immediately transmitted to the rack gear.

The housing 3 for accommodating the rack has a cylindrical shape whose axial direction is the left-right direction of the vehicle, and a connecting tube 4 is integrated with the left and right lower end portions.

As shown in FIG. 2, two anti-vibration bushes 5 which are press-fitted into the connecting cylinder 4 are of the same shape and are arranged in the front-rear direction (axial direction). 5 is an inner cylinder 11, an outer cylinder 12 arranged around the inner cylinder,
A rubber-like elastic body 13 which is vulcanized and bonded between the inner cylinder 11 and the outer cylinder 12 is provided.

The inner cylinder 12 is a thick metal cylindrical member, and a bolt 16 for supporting the frame in a central hole 15.
(See FIG. 1) can be penetrated. An inner cylinder flange 17 that rises in a direction perpendicular to the axis is integrally formed around the entire outer end of the inner cylinder 11 in the axial direction (the front-rear direction of the vehicle).

The outer cylinder 12 is a thin cylindrical member made of metal, and is formed shorter than the axial length of the inner cylinder 11.
It is press-fitted into the connecting cylinder 4 of the housing 3. At the axially outer end of the outer cylinder 12, an outer cylinder flange 18 that rises in a direction perpendicular to the axis is formed in an axially inner side than the inner cylinder flange 17. The outer diameter of the outer cylinder flange 18 is formed to be larger than the outer diameter of the inner cylinder flange 17 and is in contact with the axial end face 19 of the connecting cylinder 4 of the housing 3.

The rubber-like elastic body 13 includes the inner cylinder 11 and the outer cylinder 12.
And vulcanize the two together, and also intervene between the inner cylinder flange 17 and the outer cylinder flange 18 in a continuous manner, and vulcanize the two flanges 17 and 18 to form a flange rubber. The unit 20 is constituted.

The inner cylinder 11 extends in a direction perpendicular to the axis of the rubber-like elastic body 13.
On both left and right sides of the inner cylinder 11, there is formed a circular part 21 which is open to the inner end face in the axial direction and concentric with the inner cylinder 11.
The burring portion 21 is formed to be longer than the axial length of the connecting cylinder 4 of the housing 3, and the bottom portion reaches the flange rubber portion 20.

The pair of vibration-isolating bushes 3 has a two-piece structure in which the inner ends of the inner cylinder 11 in the axial direction are in contact with each other, and the connecting cylinder 4 of the housing 3 is sandwiched from both sides in the axial direction. It has become.

In the above construction, the inner and outer cylinder flanges 11,
Because of the presence of the flange 12 and the flange rubber portion 20, the rigidity of the spring in the front-rear direction (axial direction) can be increased, and the hysteresis loss can be reduced. Therefore, as compared with Conventional Example 2, assembly cost and vulcanization mold cost can be reduced, and stick-slip can be eliminated.

[Second Embodiment] FIG. 5 is a sectional view of a vibration isolator according to a second embodiment, FIG. 6 is a side view thereof, and FIG.
FIG. 7 is a sectional view taken along line BB of FIG. 6. In this embodiment, unlike the first embodiment, the vibration isolator 1 adopts a one-piece structure. That is, the inner cylinder 11 of the vibration isolating bush 5 is formed to be slightly longer than the length of the connecting cylinder 4 of the housing 3 in the front-rear direction.
The length in the front-rear direction (axial direction) of the rubber elastic body 13 and the bulging portion 21 is also set to be large.

Therefore, as compared with the two-piece structure, the vibration isolator 1
Is further reduced. Other configurations and operations are the same as those in the first embodiment.

[0032]

As is clear from the above description, according to the present invention, the inner and outer flanges are integrally formed at the axial ends of the inner and outer cylinders, and the flange rubber is vulcanized and bonded between them. By satisfying the required front-back, left-right and up-and-down required spring characteristics required as a vibration-isolating bush, assembly costs and vulcanizing mold costs can be reduced, and furthermore, generation of abnormal noise due to stick-slip can be prevented. In particular, if the rack housing of the steering mechanism is used as an anti-vibration bush for supporting in an anti-vibration manner, the steering response can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a steering mechanism employing a vibration isolator according to the present invention.

FIG. 2 is a cross-sectional view of a two-piece vibration isolator according to the first embodiment, which is also used for a rack housing.

FIG. 3 is a side view of the same.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 shows a one-piece vibration-isolating bush structure according to a second embodiment of the present invention.

FIG. 6 is a side view of the same.

FIG. 7 is a sectional view taken along line BB of FIG. 6;

FIG. 8 is a cross-sectional view of an anti-vibration bush of Conventional Example 1.

FIG. 9 is a cross-sectional view showing a state of being attached to a rack housing or the like.

FIG. 10 is an exploded view of an anti-vibration bush of Conventional Example 2.

FIG. 11 is a cross-sectional view showing a state of being attached to a rack housing or the like.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration isolator 2 Steering mechanism 3 Housing 4 Connecting cylinder 5 Anti-vibration bush 11 Inner cylinder 12 Outer cylinder 13 Rubbery elastic body 17 Inner cylinder flange 18 Outer cylinder flange 20 Flange rubber part 21 Curved part

Claims (4)

[Claims] 1. An inner cylinder, an outer cylinder disposed around the inner cylinder, and a rubber-like elastic body vulcanized and bonded between the inner cylinder and the outer cylinder, and an axially outer end of the inner cylinder. An inner cylinder flange that rises in the direction perpendicular to the axis is integrally formed with the portion, and an outer cylinder flange that rises in the direction perpendicular to the axis is integrally formed at the axially outer end of the outer cylinder inside the inner cylinder flange in the axial direction. An anti-vibration bush in which a flange rubber portion of the rubbery elastic body is vulcanized and bonded between an outer cylinder flange and an inner cylinder flange. 2. The vibration-isolating bush according to claim 1, wherein said rubber-like elastic body is provided with a bulging portion which is opened on an inner end face in the axial direction on both left and right sides in a direction perpendicular to the axis with respect to said inner cylinder. 3. The anti-vibration bush according to claim 1, wherein the anti-vibration bush supports the rack housing of the steering mechanism in an anti-vibration manner. 4. An anti-vibration device according to claim 1, 2 or 3, wherein a pair of anti-vibration bushes are provided in the axial direction of the bush mounting member, and the axially inner end portions thereof are arranged in contact with each other.