JPH0623584B2 - Anti-vibration bush - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an anti-vibration bush in which an anti-vibration rubber body is interposed between an inner cylinder and an outer cylinder to block vibration transmission between the inner and outer cylinders.

2. Description of the Related Art For example, in a floor shift type control linkage mechanism of an automobile transmission, a support rod 1 as shown in FIG. 3 may be used to support a control lever connected to a control rod. In this support rod 1, a flange portion 2 at the tip is connected to a control lever (not shown), and a cylindrical outer cylinder 3 at the base end is supported by a bracket 5 via a vibration-proof rubber body 4. There is.

Specifically, as shown in FIG. 4, the vibration-proof rubber body 4 in which the inner cylinder 6 is inserted is concentrically inserted into the outer cylinder 3 having the same length as the inner cylinder 6, and the vibration-proof rubber body 4 is also inserted. Embossed portions 5a are formed on both end surfaces of the bracket 5 to serve as washers.
And a washer having an embossed portion 7a formed thereon, and a bolt 8 and a nut 9 to be inserted into the inner cylinder 6
And the bracket 5 and washer 7 together with the anti-vibration rubber body 4
Are tightened together. And the anti-vibration rubber body 4
Serves to prevent the engine vibration from being transmitted from the bracket 5 side to the control lever.

The anti-vibration rubber body 4 is made of rubber having an appropriate hardness and is integrally formed in a cylindrical shape. As shown in FIG. 4, the bracket 5 and the washer are provided at the central portions of both end surfaces thereof. A dish-shaped recess 10 for receiving the embossed portions 5a, 7a of 7 is formed in advance. The diameter of the recess 10 is the same as or smaller than the diameter of the general outer peripheral surface of the vibration-proof rubber body 4.

Further, the outer cylinder 3 is provided on the outer peripheral surface of the anti-vibration rubber body 4 facing the outer cylinder 3.
In addition to a plurality of ridges 11 which are press-fitted to the inner peripheral surface 12, a stopper portion 13 which is opposed to the inner peripheral surface 12 via a minute gap is formed in a protruding manner. 13 serves to prevent an excessive relative displacement in the diametrical direction between the inner cylinder 6 and the outer cylinder 3.

Further, a large-diameter flange portion 14 is extendedly formed so as to cover the end surface of the outer cylinder 3 at both peripheral edge portions of the vibration-proof rubber body 4 in the axial direction. Direct metal contact between the bracket 5 and the washer 7 is prevented.

That is, in the above-described structure of the vibration-proof bush, normally only the ridge 11 is pressed against the inner peripheral surface 12 of the outer cylinder 3, so that the spring constant with respect to the radial displacement is kept relatively small. This interrupts the transmission of vibrations. Further, when the control lever is operated and a large input is applied, the inner peripheral surface 12 of the outer cylinder 3 is pressed against the stopper portion 13, so that the spring constant rises sharply.

Problems to be Solved by the Invention According to the conventional structure as described above, since the shoulder portions 15 of the embossed portions 5a and 7a, which are the sloped portions of the bracket 5 and the washer 7, are located inside the outer cylinder 3, When the bracket 5 and the washer 7 are fastened with the bolt 8 and the nut 9, the slope of the recess 10 on the vibration isolating rubber body 4 side corresponding to the root portion of the flange 14 of the vibration isolating rubber body 4, that is, the shoulder portion 15. The portion 10a receives a compressive force not only in the axial direction of the antivibration rubber body 4 but also in the diametrical direction. Therefore, as shown in FIG. 2, the radial spring characteristic (spring constant) of the vibration-proof rubber body 4 changes greatly depending on the tightening amount (tightening margin) of the bolt 8 and the nut 9. As a result, unless the tightening margins of the bolt 8 and the nut 9 are strictly controlled, the spring characteristics of the vibration-proof bush vary, which is not preferable.

The present invention has been made in view of the above problems,
It is an object of the invention to provide a structure in which the influence of the tightening margin of the bolt and the nut on the spring characteristic of the vibration-proof rubber body is minimized.

Means for Solving the Problems According to the present invention, in a sloped portion of a dish-shaped recess that matches the embossed portion of a washer on both end surfaces of a vibration-proof rubber body, a void portion that avoids contact with the washer is formed in an annular shape. It is characterized by having done.

Action According to this structure, it is possible to prevent the slope of the embossed part on the washer side from directly contacting the slope of the corresponding recess on the side of the washer due to the gap, and the anti-vibration rubber body is tightened by the bolt and nut tightening force. The compressive deformation applied in the diametrical direction is relaxed. As a result, the width of change in the spring characteristics of the vibration-proof rubber body due to the tightening of the bolts and nuts is reduced, and it is possible to suppress variations in the spring characteristics of the vibration-proof bush.

Embodiment 1 FIG. 1 is a diagram showing a more specific embodiment of the present invention, in which portions common to FIG. 4 are designated by the same reference numerals.

As shown in FIG. 1, of the both ends of the vibration-proof rubber body 4, the washer 7 and the portion of the bracket 5 that also serves as the washer are in pressure contact, that is, the washer 7 and the shoulder of the embossed portions 7a, 5a on the bracket 5 side. This is different from the conventional structure in that an annular void portion 16 is formed with a minute depth in a portion along the flange portion 14 from the slope portion 10a of the depression 10 to which the portion 15 is pressed.

According to this structure, when the anti-vibration rubber body 4 is tightened together with the bracket 5 and the washer 7 using the bolt 8 and the nut 9, the anti-vibration rubber body 4 is axially moved by the tightening force of the bolt 8 and the nut 9. Although there is a gap 16 in the vicinity of the slope 10a of the recess 10 close to the root of the flange 14, the shoulder 15 that is the slope of the bracket 5 and the washer 7 corresponds to the slope 10a. Direct contact with the vicinity of the slope 10a is prevented.

Therefore, the compressive deformation force in the diametrical direction exerted on the antivibration rubber body 4 by the bracket 5 and the washer 7 in the vicinity of the shoulder portion 15 becomes smaller than in the conventional case, and the antivibration rubber body 4 is tightened by tightening the bolt 8 and the nut 9. The width of the change in the spring characteristics of is greatly suppressed.

FIG. 2 shows changes in the spring characteristics of the vibration-proof rubber body 4 due to the tightening margins of the bolts 8 and nuts 9 described above. The structure of the present invention has a wider range of change in spring characteristics than the conventional structure. It turns out that it is extremely small.

EFFECTS OF THE INVENTION As described above, according to the present invention, the gap is formed annularly on the sloped portion of the dish-shaped depression against which the washer is pressed on both end surfaces of the anti-vibration rubber body. Even if the anti-vibration rubber body is compressed between the washers, the void prevents direct contact between the washer and at least the slope of the depression, so that the diametrical compressive deformation force of the anti-vibration rubber body in the vicinity of the depression is reduced. Will be alleviated. As a result, the amount of tightening of bolts and nuts, that is, the width of change in the spring characteristics of the anti-vibration rubber body in accordance with the tightening allowance is significantly smaller than before, eliminating the need for troublesome tightening allowance management as in the past. It is possible to suppress variations in spring characteristics of the vibration isolation bush.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a characteristic view showing the relationship between the tightening margins of bolts and nuts and spring characteristics.
FIG. 3 is an exploded perspective view of a main part of a control linkage mechanism of a transmission, and FIG. 4 is a sectional view showing an example of a conventional vibration-proof bush used in the mechanism of FIG. 3 ... Outer cylinder, 4 ... Anti-vibration rubber body, 5 ... Bracket (washer), 5a ... Embossed part, 6 ... Inner cylinder, 7 ...
Washer, 8 ... Bolt, 9 ... Nut, 10 ... Dimple, 10a ... Slope, 14 ... Flange, 15 ...
Shoulder, 16 ... void.

Claims (1)

[Claims] 1. An inner cylinder and an outer cylinder, which are arranged concentrically and have the same length as each other, are interposed between the inner cylinder and the outer cylinder, and have a large diameter at both peripheral edge portions in the axial direction. A cylindrical anti-vibration rubber body having a flange portion formed on both end surfaces and a dish-shaped recess having the same diameter as or smaller than the outer peripheral surface, and arranged on both side surfaces of the anti-vibration rubber body. And an embossed portion that conforms to the recess is bulged and formed, and comprises an outer cylinder and a pair of washers of the same diameter or larger, and a bolt and a nut that are inserted into the inner and outer cylinders and the washer. In the vibration-proof bushing in which the washer and the vibration-proof rubber body are tightened together by means of and the vibration-proof rubber body is pressed in the axial direction thereof, and the flange portion is pressed by the outer cylinder and the washer. The contact surface with the washer is attached to the slope of the An anti-vibration bush characterized in that a void portion for avoiding touch is formed in an annular shape.