JP2013217405A - Vibration-proof bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibration-proof bush used for a connecting site between a vehicle body and a vibration source such as an engine and a wheel in a vehicle such as an automobile, the vibration-proof bush capable of further decreasing noise in the vehicle.SOLUTION: A vibration-proof bush includes a shaft member 2, an outer cylinder 3 extending parallel to an axis 53 and enclosing the shaft member 2, a rubber elastic body 1 interposed between the shaft member 2 and the outer cylinder 3, and a pair of bored parts 4 axially penetrating the rubber elastic body 1. The pair of bored parts 4 is arranged at positions that pinch the shaft member 2 in a first direction 51 perpendicular to the axis in the rubber elastic body 1, and is extended in a second direction 52 perpendicular to the axis and orthogonal to the first direction 51 perpendicular to the axis. A bridge membrane 11 is included in the bored part 4, the membrane spanning from a side close to the outer cylinder 3 to a side close to the shaft member 2. The bridge membrane 11 is extended along the axial direction or the second direction 52 perpendicular to the axis, and is curved along a smooth curved line in a cross-sectional shape in a film thickness direction.

Description

  The present invention relates to an anti-vibration bush used for a connection portion between a vibration source such as an engine or a wheel portion and a vehicle body in a vehicle such as an automobile.

  In general, the anti-vibration bushing is used for the purpose of vibration damping, buffering, etc., at a connecting portion between a vibration source such as a wheel, an engine or a wheel part and a vehicle body. They are joined by a vibration-proof substrate made of a rubber elastic body. In particular, a connecting rod called a torque rod for supporting the engine, which is a vibration source, from the vehicle body is protected at both ends in the longitudinal direction of the arm-shaped body in order to suppress movement and vibration in the roll direction of the engine. A vibration bush is provided. Various types of anti-vibration bushes and anti-vibration devices including the same have been proposed.

  In the anti-vibration bush described in Patent Document 1 below, a bow-shaped straight portion is provided on the top and bottom of the rubber elastic body so as to sandwich the inner cylinder and its left and right portions. "Member" is arranged. Each “rubber middle mold member” has a rubber elasticity via a column-shaped connecting portion at a central location in the axial direction and the horizontal direction, that is, at a central location in the vertical direction when the arms are arranged in the vertical direction. It is connected to the body and supported. A substantially constant gap is formed between the rubber intermediate mold member and the surrounding rubber elastic body, and the rubber intermediate mold projects against the surrounding rubber elastic body as the inner cylinder is displaced relative to the outer cylinder. Hit.

  Further, in Patent Document 2 below, in an anti-vibration bush for automobiles called “to-collect bush or toe control bush”, the cross sections provided on both sides sandwiching the inner cylinder are arc-shaped straight portions (extend in the axial direction). It is described that the thin film portion provided at one end portion (“bottom portion”) in the axial direction of the straight portion is improved. That is, it describes that the shape configuration in the vicinity of the thin film portion is devised so that cracks are not generated due to repeated tensile stress.

  On the other hand, for example, in an anti-vibration device described in Patent Document 3 described below and interposed between an engine and a vehicle body, a pair of straight portions are provided on a rubber elastic body of an anti-vibration bush on the engine side. . These curly portions are arranged at positions sandwiching the inner cylinder from both sides in the longitudinal direction (first axis perpendicular direction) of the arm (“bracket plate”), and extend in the arm width direction (second axis perpendicular direction). Both ends are in contact with the outer cylinder. And the area other than both ends in each straight part is opposed to the wall surface of the shaft member side rubber part and the wall surface of the outer cylinder side rubber part through a relatively small gap, and is abutted against a large compression event A gap is formed.

JP 2011-011475 A JP 2000-104776 A JP 2006-194370 A

  In recent years, demand for in-vehicle noise has increased, and various types of noise have been reduced. For this reason, there may be a problem of noise caused by rubbing between rubbers constituting the rubber elastic body at the corner of the anti-vibration bush. Therefore, the present invention seeks to provide a vibration-proof bushing that can further reduce vehicle interior noise.

  In order to reduce noise such as a rubbing sound generated in the area of the abutting interval portion in the straight portion, the present inventor can reduce the noise from the shaft member side rubber portion to the outer cylinder side in the area of the abutting interval portion. An attempt was made to place a bridge film that spans the rubber part. In addition, in the structure bridge | crossed only by the edge part of the axial direction like the said patent document 2 only in the column-shaped bridge | bridging part of the center point location like the said patent document 1, it is not very effective in reduction of a rubbing sound. Or thought that the effect did not last. Therefore, firstly, it was considered that a bridge film extending in the axial direction of the vibration isolating bush or the width direction of the arm should be provided. During further investigation, the present inventor has found that the bridge film may break relatively early under conditions of being subjected to a large load and large deformation. Therefore, the idea of making the cross-sectional shape of the bridge part foldable so that it can follow even if the gap between the wall surfaces of the straight part widens greatly due to large deformation in the pulling direction and can cope with compression as well. It was. The present invention was completed at the end of the verification test.

  That is, the vibration isolating bush according to the present invention includes a shaft member, an outer cylinder extending parallel to the shaft and surrounding the shaft member, a rubber elastic body interposed between the shaft member and the outer cylinder, and the rubber elasticity A pair of straight portions penetrating the body in the axial direction, and the pair of straight portions are disposed at a portion sandwiching the shaft member from the first axis perpendicular direction in the rubber elastic body, in the first axis perpendicular direction An anti-vibration bush that extends along a direction perpendicular to the second axis perpendicular to each other, and is provided with a bridge film spanned from the outer cylinder side to the shaft member side in the straight portion, , Extending along the axial direction or the direction perpendicular to the second axis, and curved along a smooth curve (smooth curve without bending) when viewed in a cross-section in the film thickness direction And

  In a preferred embodiment, the bridge film has a substantially constant width except for both ends in the cross-sectional shape. In some preferred embodiments, the bridge film has a wavy shape that oscillates along a U-shaped, S-shaped, or linear imaginary line in the cross-sectional shape.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to prevent or reduce the noise transmitted from a vibration-proof bushing into a vehicle, it can prevent or reduce that the bridge | bridging film for that is damaged over time.

It is the front view which looked at the anti-vibration bush of 1st Embodiment from the axial direction. It is sectional drawing which passes along locations other than the bridge | bridging film in a center axis | shaft and a corner part about the anti-vibration bush of FIG. It is sectional drawing which passes along a central axis and each bridge | bridging film | membrane about the anti-vibration bush of FIG. It is an expanded sectional view about the cross-sectional shape of a bridge film. It is the front view which looked at the anti-vibration bush of 2nd Embodiment from the axial direction. It is sectional drawing which passes along a central axis and each bridge | bridging film | membrane about the anti-vibration bush of FIG. It is an expanded sectional view similar to FIG. 4 which shows the modification of a bridge | bridging film | membrane. It is an expanded sectional view similar to FIG.4 and FIG.7 which shows the comparative example of a bridge | bridging film | membrane.

  In the anti-vibration bushing of the present invention, a bridge film that extends from the outer cylinder side to the shaft member side is disposed in the axial portion penetrating in the axial direction, particularly in the region of the abutting interval portion. Thus, it is possible to prevent or reduce the occurrence of abnormal noise due to rubbing of both wall surfaces of the straight portion at the time of relatively large compression deformation. In addition, since the bridge film is curved so as not to be bent, excessive tensile stress is not applied even when a relatively large tensile deformation occurs, and stress on a specific part in the bridge film is not generated. Concentration is also prevented or reduced. In particular, the cross-sectional shape along a smooth curve is regularly folded during large compression deformation, so that the generation of rubbing noise during folding is prevented or reduced. Preferably, the bridge film is disposed in the central portion of the abutting area of the straight portion. One bridge film may be arranged at the center in the region of the abutting interval portion of the straight portion. A plurality may be arranged at equal intervals from the center, particularly in a line-symmetric arrangement. When the anti-vibration bushing is used for an engine support or suspension link of a general passenger car such as a sedan type, the thickness of the bridge film is preferably 0.2 to 2 mm, more preferably 0.3 to 1.5 mm, and still more preferably 0.5. ~ 1.0mm.

  In a preferred embodiment, the bridge film has a transverse cross section (in the thickness direction of the bridge film) except for both ends in the spanning direction (the end connected to the outer cylinder side rubber part and the end connected to the shaft member side rubber part). The line width in the shape of the cross section) is substantially constant. This line width is the dimension in the direction perpendicular to the second axis when the bridge film extends in the axial direction, and is the dimension in the axial direction when the bridge film extends along the direction perpendicular to the second axis. . That is, in the cross section in the thickness direction of the bridge film, when an intermediate line is assumed between the wall surfaces of the rubber elastic body facing each other with the straight portion interposed therebetween, it can be said that the dimension is in the direction along the intermediate line. At both ends of the bridge film, that is, at the end on the outer cylinder side and the shaft member side, the line width can be made larger than that at other locations. Therefore, for example, about 30% or less, especially 25% or less, preferably 20% or less in the dimension in the spanning direction, both ends having different line widths can be used. Further, at least at a place other than both ends, the difference between the maximum value and the minimum value in the line width can be 20% or less, particularly 15% or less, preferably 10% or less of the average width. Such a cross-sectional shape further prevents or reduces stress concentration on a specific part. Note that “curved along a smooth curve” for the cross-sectional shape of the bridge film typically means that the center line of the cross-sectional shape is curved as such.

  In a preferred embodiment, the bridge film has a finer wavy shape extending in a U-shape, an S-shape or a straight line in the cross section. That is, the center line in the cross section of the bridge film has a sine wave shape or other smooth curved wave shape that oscillates around a U-shaped, S-shaped or linear imaginary line. With such a shape, the surface of the bridge film is prevented or reduced from being rubbed during bending and stretching due to compression and decompression, and stress concentration on a specific part is prevented or reduced. In addition, when it is U-shaped or S-shaped as a whole, the amplitude of the fine corrugation as described above (twice the height) is preferably 0.2 to 2 times the thickness of the bridge film, more preferably 0.3 to 1.5 times. Moreover, when it is linear as a whole, the amplitude of the fine wave is preferably 0.3 to 3 times, more preferably 0.3 to 2 times the thickness of the bridge film. The space between the wall surfaces of the rubber part at the place where the bridge film is disposed is, for example, 4 to 10 mm when not loaded. The fine corrugation can be performed, for example, for 0.5 to 4 periods (180 to 720 degrees) of a sine wave.

  In the anti-vibration bush of the present invention, the shaft member is not limited to a cylindrical shape, and may be solid. In the case of a cylindrical shape, the shaft member forms an inner cylinder corresponding to the outer cylinder. The cross sections of the shaft member and the outer cylinder may be circular, rectangular, oval, etc., and the hollow portion in the inner cylinder may be eccentric. The outer peripheral surface of the shaft member and the inner peripheral surface of the outer cylinder are not limited to a cylindrical shape, but may be a bulging shape such as a shape along a spherical surface. On the other hand, the bridge film is usually an integral member that is vulcanized and formed simultaneously with the other part of the rubber elastic body. If the bridge membrane extends in a direction perpendicular to the axis, it can be provided by a mold partition.

  Further, in a preferred embodiment, when the bridge film is disposed in the axial direction, the bridge film extends over the entire region excluding both end portions in the axial direction of the straight portion. Moreover, when arrange | positioning along said 2nd axis perpendicular direction, it extends over the whole region except the both ends of this direction in a corner part. The both end portions are typically portions having a larger radial dimension than other regions. In a further preferred embodiment, the abutting gap portion is configured so that the distance increases from the central portion toward at least one of the axial direction and the second axis perpendicular direction. In this way, it is possible to further reduce the impact at the time of abutment. Further, in a preferred embodiment, by performing unevenness forming processing such as embossing on the wall surface of the abutting gap portion, it is possible to further reduce noise by preventing adsorption between the rubber wall surfaces. It is.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated still in detail, this invention is not limited to an Example.

  1 to 6 show a set of anti-vibration bushes 10 and 10 'used for a series of engine support parts or suspension links. In a specific embodiment, the vibration isolating bush 10 shown in FIGS. 1 to 3 has a central shaft 53 arranged in the horizontal direction, and the vibration isolating bush 10 ′ shown in FIGS. It is arranged in the vertical direction. FIG. 4 is an enlarged cross-sectional view showing the cross-sectional shape of the bridge film 11 common to these two anti-vibration bushes.

  In any of the vibration isolating bushes 10, 10 ′, the outer peripheral surfaces of the shaft members 2, 2 ′ are circular and are arranged coaxially with the cylindrical outer cylinder 3. Between these components, a substantially cylindrical rubber elastic body 1 is disposed by being vulcanized and bonded thereto. In the rubber elastic body 1, the straight portion 4 that penetrates the rubber elastic body 1 in the axial direction at a position facing from the first axis-perpendicular direction 51 (main load and deformation direction) with the shaft members 2 and 2 ′ sandwiched therebetween. -1,4-2 are provided. These straight portions 4 generally extend along a second axis-perpendicular direction 52 that is orthogonal to the first axis-perpendicular direction 51. In addition, the straight portion 4 includes an abutting interval portion 41 in which the rubber portion 12 on the shaft member side and the rubber portion 13 on the outer cylinder side face each other through a clearance and are abutted at the time of relatively large compression deformation, The rectangular region (when viewed from the axial direction) sandwiches both ends 42 in the direction perpendicular to the axis (FIGS. 1 and 5) and both ends 43 in the axial direction (FIGS. 2 and 6). Both end portions 42 in the direction perpendicular to the axis are wide portions extending from both ends of the abutting spacing portion 41 in the second direction perpendicular to the axis 52, and the vibration isolating bush 10, 10 ′ is formed on the inner surface of the outer cylinder 3. Has reached. Similarly, the axial end portions 43 are portions where the gap between the wall surfaces of the rubber portion 12 on the shaft member side and the rubber portion 13 on the outer cylinder side is larger than the interval in the abutting interval portion 41. is there.

  In any anti-vibration bush 10, 10 ′, the gap between the rubber part 12 on the shaft member side and the rubber part 13 on the outer cylinder side is the smallest, corresponding to the first abutted portion during large compression deformation, A bridge film 11 is provided, and extends from the central part of one side of the rectangular region formed by the abutting interval part 41 to the central part of the opposite side. That is, the area of the abutting interval portion 41 is divided into two, and in particular, it is divided into two equal parts. However, in the vibration isolating bush 10 of FIGS. 1 to 3, the bridge film 11 extends in the axial direction, and in the vibration isolating bush 10 ′ of FIGS. 5 to 6, the bridge film 11 extends in the second axis perpendicular direction 52. Yes. In the illustrated example, the cross section of the bridge film 11 is constant except for both ends in the direction in which the bridge film 11 extends. In the specific example shown in the figure, the line width of the bridge film 11 is 0.8 mm.

  As shown in FIG. 4, in the illustrated example, the cross-sectional shape of the bridge film 11 is a U-shape as a whole, and is a curved shape having a sine wave shape around a U-shaped virtual line. It has become. More specifically, in the cross-sectional shape, the line width is constant from the connection portion with the rubber portion 12 on the shaft member side to the connection portion with the rubber portion 13 on the outer cylinder member side, and is equivalent to two cycles. A wavy small curve corresponding to the phase of the sine wave (for 720 degrees) is formed. Here, the line width is a dimension in the second axis-perpendicular direction 52 or a dimension in the direction of the intermediate line 45 between the wall surfaces. Since the line width is constant in the cross-sectional shape of the bridge film 11, both the contour line and the center line 15 form a curve having the same shape and size.

  FIG. 7 shows a modification of the cross-sectional shape of the bridge film 11. In the vibration-proof bushing 10 ″ of this modification, the cross-sectional shape of the bridge film 11 extends linearly in the first axis-perpendicular direction 51 as a whole, and has a sine wave shape centered on the straight virtual line. More specifically, as in the case of Fig. 4, a small wavy curve corresponding to the phase of a sine wave for two periods (for 720 degrees) is formed. However, the bridge film 11 has a large line width at both end portions in the first axis-perpendicular direction 51, that is, at portions connected to the rubber portions 12 and 13 on the shaft member side and the outer cylinder side. Therefore, at both ends, the shape of the center line 15 is different from the shape of both contour lines, and the bridge film shown in FIG. It can be applied to any of the vibration-proof bushing configurations.

  When the cross-sectional shape is as shown in FIG. 4 or FIG. 7, when compression and pulling are repeated at the location of the abutting interval portion 41, the stress is applied evenly without concentrating the stress on a specific portion. However, it can be folded and released smoothly. Moreover, it can prevent effectively that both wall surfaces of the space | interval part 41 for abutting collide, and generation | occurrence | production of friction can be especially prevented. In addition, when the degree of deformation of compression and tension and the frequency of repetition thereof are large, the form of FIG. 4 was preferred to FIG.

  FIG. 8 shows the bridge film 11 in the anti-vibration bush 10 ′ ″ of the comparative example. The bridge film 11 extends linearly in the first perpendicular axis direction 51 and is not corrugated. Although abnormal noise such as rubbing noise can be prevented, durability is inferior when relatively large compression and tensile deformation is repeated, particularly when a large tensile deformation is performed. After that, a desired degree of noise prevention effect cannot be expected.

  Next, other configurations of the vibration isolating bush 10 of FIGS. 1 to 3 and the vibration isolating bush 10 ′ of FIGS. 5 to 6 will be described.

  First, the other specific structure in the vibration isolating bush 10 of FIGS. 1-3 is demonstrated. As shown in FIGS. 1 and 2, in the illustrated example, the interval between the wall surfaces in the abutting spacing portion 41 is the narrowest in the central portion in both the first axis perpendicular direction 51 and the axial direction, It spreads away from the center. Further, since both end portions 42 in the direction perpendicular to the axis extend along the inner surface of the outer cylinder 3, the straight portion 4 has an arcuate shape when viewed from the axial direction. On the other hand, the boundary between the axial end portions 43 and the abutting gap 41 is not very clear. When viewed from the second axis-perpendicular direction 52, the bridge film 11 has a shape in which both ends enter into the inside and enter into a semicircle in the illustrated example.

  Further, the rubber elastic body 1 is not provided with any other straight portion, and the entire portion of the rubber member 1 sandwiching the shaft member 2 from the second axis-perpendicular direction 52 is the solid support portion 14. On the other hand, the shaft member 2 includes a columnar main body 21 to which the rubber elastic body 1 is connected to the outer peripheral surface and a connecting plate 22 extending from both ends in the axial direction. The connecting plate 22 includes an arm, a bracket, and the like. A circular hole is provided for fastening by screwing or the like.

  Next, another specific configuration of the anti-vibration bush 10 ′ shown in FIGS. As shown in FIG. 5, when viewed from the axial direction, the abutting gap portion 41 has a constant gap between the wall surfaces over the entire region and is curved along the outer cylinder 3. Further, both end portions 42 in the direction perpendicular to the axis have a substantially oval shape that is long in the radial direction. Also, when viewed from the second axis-perpendicular direction 52, the distance between the abutment spacing portions 41 is substantially constant, but is the narrowest at the central portion and slightly widens toward both ends. On the other hand, a second curb portion 44 is provided in contact with the shaft member 2 ′ at a position where the shaft member 2 ′ is sandwiched from the second perpendicular axis direction 52 in the rubber elastic body 1.

  The shaft member 2 ′ is basically cylindrical and swells in a spherical shape at a location surrounded by the outer cylinder 3. That is, the shaft member 2 ′ is composed of a ball zone forming cylinder portion 23 and a cylinder portion 24 extending from both ends.

  The anti-vibration bush of the present invention can be used in a connection part between a vibration source such as an engine or a wheel part and a vehicle body in a vehicle such as an automobile.

1 ... Rubber elastic body; 10 ... Anti-vibration bush; 11 ... Bridge membrane;
12 ... shaft member side rubber part; 13 ... outer cylinder side rubber part; 14 ... solid support part;
15 ... center line of cross section of bridge membrane; 2 ... shaft member;
2 '... inner cylinder as shaft member; 21 ... cylindrical body; 22 ... connecting plate;
23 ... Ball zone forming cylinder part; 24 ... Cylinder part; 3 ... Outer cylinder;
4 ... a straight part; 41 ... abutment spacing part; 42 ... both ends of the axis perpendicular direction;
43 ... Both ends in the axial direction; 44 ... Straight section of the inner cylinder; 45 ... Middle line;
51 ... first axis perpendicular direction; 52 ... second axis perpendicular direction; 53 ... central axis.

Claims (4)

A shaft member;
An outer cylinder extending parallel to the central axis and surrounding the shaft member;
A rubber elastic body interposed between the shaft member and the outer cylinder;
A pair of straight portions penetrating the rubber elastic body in the axial direction;
The pair of straight portions are disposed at a portion sandwiching the shaft member from the first axis perpendicular direction in the rubber elastic body, and extend along the second axis perpendicular direction orthogonal to the first axis perpendicular direction. A swing bush,
In the curb portion, a bridge film is provided that spans from the outer cylinder side to the shaft member side,
The bridge film extends along the axial direction or the second axis perpendicular direction, and is curved along a smooth curve in a cross-sectional shape in the film thickness direction.   2. The vibration-isolating bushing according to claim 1, wherein the bridge film has a substantially constant line width except for an end portion on an outer cylinder side and a shaft member side in a cross-sectional shape.   The anti-vibration bush according to claim 1 or 2, wherein the bridge film has a wave shape that vibrates about a U-shaped, S-shaped, or linear imaginary line in a cross-sectional shape.   The bridge film extends in the axial direction over the entire region except for both axial end portions in the straight portion, or extends in the second axial perpendicular direction over the entire region except for both end portions in the second axial perpendicular direction in the straight portion. The anti-vibration bush according to any one of claims 1 to 3.

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