JP2009008118A - Rubber bushing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber bushing excellent in fatigue durability maintaining ride comfort while increasing axially perpendicular stiffness. <P>SOLUTION: This bushing is provided with a roughly cylindrical shape rubber elastic body 3 connecting an inner tube 1 and an outer tube 2. An annular depression part 4 is formed on an outer circumference surface of the inner tube 1 over a whole circumference at an intermediate section in a tubular axis X direction, and an annular protrusion part 6 is formed on an inner circumference surface of the rubber elastic body 4 with corresponding the same. The annular protrusion part 6 is pressed in the annular depression part 4 and is connected under a non-adhesion condition. Compression rate of the rubber elastic body 3 of the annular protrusion part 6 is set higher than at least an end part of the tubular axis X direction. An inner diameter of the rubber elastic body 3 is formed in such a manner that the same gradually increases toward both end sides from a vicinity of the annular protrusion part 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rubber bush in which inner and outer cylinders are connected by a rubber elastic body.

  Conventionally, this type of rubber bush has been widely known. For example, the other cylindrical body is provided over the entire circumference in the axially central portion of an inner cylinder or outer cylinder to which a rubber sleeve (rubber elastic body) is vulcanized and bonded. There is one in which a spring constant (rigidity) in a direction orthogonal to the cylinder axis (hereinafter simply referred to as a direction perpendicular to the axis) is increased by forming a convex portion projecting toward (Patent Document 1).

Moreover, it has an attachment ring (outer cylinder) in which a pair of convex portions projecting inward are formed on the left and right sides of the central portion in the cylinder axis direction, and an inner side where a rubber member (rubber elastic body) is bonded to the attachment ring In some cases, the ring (inner cylinder) is press-fitted and fixed to reduce the spring constant (rigidity) in the axial direction and prevent the cylinder axis from coming off (Patent Document 2).
Japanese Utility Model Publication No. 61-57009 Japanese Patent Laid-Open No. 9-164827

  By the way, a rubber bush called a damper bottom bush is disposed at a lower end portion of a damper provided in the suspension of the automobile. This damper bottom bush is subjected to a torsional (twisting) or twisting (twisting) load where a large load is applied in the direction perpendicular to its axis. There is a desire to improve ride comfort.

  On the other hand, in the rubber bush of the above-mentioned patent document 1, although the axial rigidity of the rubber sleeve is increased due to the presence of the convex portion, the compression allowance is reduced and the load in the axial direction is reduced as the thickness is reduced. Impact is easily transmitted, which is disadvantageous in terms of fatigue durability and ride comfort. In addition, there is room for improvement in this respect because it has not been sufficiently studied for torsion and twisting loads.

  On the other hand, the rubber bush of Patent Document 2 has no protrusions in the vertical direction of the mounting ring and maintains a large compression allowance. Therefore, although it is excellent in terms of fatigue durability and riding comfort, Since the rigidity is low, there is a difficulty in handling stability. The point which does not consider about the load of a twist or a twist is also the same as that of patent document 1.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a rubber bush suitable for a damper bottom bush or the like that has excellent fatigue durability and is comfortable to ride while enhancing the rigidity of the shaft. There is to do.

  In order to achieve the above object, in the present invention, an annular convex portion is formed at an intermediate portion in the cylinder axial direction of the rubber elastic body, and this is pressed into the annular concave portion of one cylindrical body of the inner and outer cylinders without being bonded. did.

  Specifically, a rubber bush including an inner cylinder, an outer cylinder that surrounds the outer periphery thereof, and a substantially cylindrical rubber elastic body that connects them, the outer peripheral surface of the inner cylinder and the inner periphery of the outer cylinder An annular recess extending over the entire circumference is formed in either one of the surfaces at an intermediate portion in the cylinder axis direction, and an annular projection is formed on the inner circumferential surface or outer circumferential surface of the rubber elastic body correspondingly. The annular convex portion is press-fitted into the annular concave portion and connected in a non-adhered state, and the compression rate of the rubber elastic body in the annular convex portion is higher than at least the end portion in the cylindrical axis direction. (Claim 1).

  If it does so, since the cyclic | annular convex part of the rubber elastic body engage | inserted by the cyclic | annular recessed part of a cylinder is compressed and hardened, axial rigidity becomes high and it becomes excellent in steering stability. Despite this, the thickness of the rubber elastic body including the annular convex portion is large in the axial direction, that is, the compression allowance is large, so that the ride comfort is not greatly impaired, and the fatigue durability is also excellent. Yes.

  In addition, a part of the annular convex part that does not fit into the annular concave part protrudes from the annular concave part, and the thickness of the rubber elastic body is artificially increased on both sides in the cylindrical axis direction. improves.

  In addition, the rubber elastic body is compressed and hardened at the intermediate portion in the cylinder axis direction, while the compression rate of the rubber elastic body is low at both ends in the cylinder axis direction, so that the twisting rigidity is lowered. It is also advantageous for ride comfort.

  Furthermore, by making the concave-convex fitting of the annular convex portion and the annular concave portion over the entire circumference in the cylindrical axis direction non-adhering, the rubber elastic body is easily displaced around the cylindrical axis, and the torsional rigidity is also reduced. Riding comfort will be improved against complex loads applied from various directions such as prying.

  In addition, since the displacement movement in the cylinder axis direction is restricted by the concave-convex fitting around the cylinder axis, the connected state is stable even if it is not bonded.

  Here, with respect to the combination of each cylindrical body and the annular convex portion and the annular concave portion, it is preferable that the annular concave portion is formed on the outer peripheral surface of the inner cylinder and the annular convex portion is formed on the inner peripheral surface of the rubber elastic body. Item 2). This is because such a configuration is easier to mold than the case where the annular recess is formed on the inner peripheral surface of the outer cylinder, and the productivity is excellent.

  Further, in the step of connecting the inner and outer cylinders, a method is generally employed in which the inner cylinder is press-fitted into the outer cylinder (hereinafter referred to as an outer cylinder or the like) integrated with the rubber elastic body from the cylinder axis direction. By adopting a concavo-convex structure, press fitting may be difficult.

  Therefore, in such a case, the inner diameter of the rubber elastic body may be formed so as to gradually increase from the vicinity of the annular convex portion toward both end sides. Then, when the inner cylinder is press-fitted into the outer cylinder or the like, it can be easily inserted because it can be inserted through a large opening, and after press-fitting, the closer to the end in the cylinder axis direction, between the rubber elastic body and the inner cylinder. Since a gap with a large interval is formed, the degree of interference between the rubber elastic body and the inner cylinder when it is squeezed is reduced, and the squeeze rigidity can be greatly reduced.

  Further, the same effect can be obtained even if the outer diameter of the inner cylinder is gradually reduced from the vicinity of the annular recess toward both ends in the cylinder axis direction (Claim 4). Becomes easier and the rigidity is further reduced.

  Specifically, the inner cylinder has a large-diameter portion with a relatively large outer diameter at an intermediate portion in the cylinder axis direction, and a small-diameter portion with a relatively small outer diameter at both ends in the cylinder axis direction. In addition, between the large diameter portion and the small diameter portion, an inclined portion having an outer diameter gradually decreasing from the large diameter portion side toward the small diameter portion side is formed, and the annular recess is opened on the outer peripheral surface of the large diameter portion. To do. And the bottom face can be made larger diameter than the said small diameter part (Claim 5).

  If it does so, a rubber elastic body will be received by the large diameter part of the predetermined width which follows the opening both sides of an annular crevice, and will become stable. Also, by making the bottom surface of the annular recess opening on the outer peripheral surface of the large diameter portion larger than the small diameter portion, when inserting the inner cylinder into the outer cylinder, etc., the annular projection is inserted without rubbing against the small diameter section. Thus, the concave and convex portions can be fitted at once while being guided to the inclined portion, and can be easily press-fitted.

  In addition, the inner cylinder has a large-diameter portion having a relatively large outer diameter at an intermediate portion in the cylindrical axis direction, while a small-diameter portion having a relatively small outer diameter is formed at both ends in the cylindrical axis direction. And the said annular recessed part is opened in the outer peripheral surface of the said large diameter part. And you may make it form the outer peripheral surface of a large diameter part including this cyclic | annular recessed part with the curved surface which continues in a cylinder axis direction (Claim 6). In this case, since the entire outer peripheral surface of the large-diameter portion including the annular concave portion is formed by a continuous wave-shaped curved surface, it is easy to press-fit, and when it is unevenly fitted or rubbed, the rubber elastic body Thus, a load is uniformly applied to suppress the occurrence of local distortion, and the tire has excellent fatigue durability and ride comfort.

  On the other hand, the rubber elastic body may be formed with annular ridges over the entire circumference on both side surfaces in the cylinder axis direction (Claim 7). By providing the protrusions in this manner, the width dimension of the annular convex portion in the cylinder axis direction can be set small, and the annular convex portion is easily bent and press-fitted easily. In addition, the compression ratio of the annular convex portion in the cylinder axis direction is relatively high, which is advantageous for regulating the displacement movement in the cylindrical axis direction, and part of the annular convex portion is easily protruded from the annular concave portion. It also helps to increase fatigue durability by increasing body thickness.

  As described above, according to the rubber bush of the present invention, it has excellent fatigue durability, high steering stability, and good ride comfort. Therefore, it can be suitably used for a damper bottom bush.

  Hereinafter, an embodiment of a rubber bush B according to the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

(First embodiment)
FIG. 1 is a longitudinal sectional view of a rubber bush B according to the present embodiment. (A) of the figure schematically shows the state before assembly, and (b) schematically shows the state after assembly. As shown in the figure, the rubber bush B is interposed between the metal inner cylinder 1, the same metal outer cylinder 2 surrounding the outer periphery of the inner cylinder 1, and the inner cylinder 1 and the outer cylinder 2. And a rubber elastic body 3 having a substantially cylindrical shape for connecting them. In the example shown in the figure, the inner cylinder 1, the outer cylinder 2, and the rubber elastic body 3 are all arranged so that the cylinder axis X coincides.

  The rubber bush B of the present embodiment is used as a damper bottom bush. Although not shown, a support member is fixed to the outer cylinder 2 so as to extend in the axial direction, while the inner cylinder 1 A support shaft is inserted in the axial direction.

  The inner cylinder 1 is made of a forged product in which a through hole 1a for inserting the support shaft passes through in the cylinder axis X direction, and has a thick intermediate portion in the cylinder axis X direction on the outer peripheral surface of the cylinder (example in the figure). Then, an annular recess 4 that is recessed in a groove shape is formed over the entire circumference around the cylinder axis X. The annular recess 4 is defined by a bottom surface 4a substantially parallel to the cylinder axis X and side surfaces 4b and 4b which are inclined so as to slightly spread from both sides of the bottom surface 4a toward the opening side, that is, radially outward. Yes.

  The inner cylinder 1 is formed such that the outer diameter thereof gradually decreases from the vicinity of the annular recess 4 toward both ends in the cylinder axis X direction, and the inclined surface 5 is seen in a cross section including the cylinder axis X. A convex curved surface is formed such that the inclination angle continuously increases from the annular recess 4 side toward the end.

  On the other hand, the outer cylinder 2 has a round pipe shape having an inner diameter larger than the outer diameter of the inner cylinder 1, and the inner peripheral surface has a substantially cylindrical shape as shown in FIG. The rubber elastic body 3 is mold-bonded.

  An annular convex portion 6 that protrudes toward the center over the entire circumference is formed at an intermediate portion of the inner circumferential surface of the rubber elastic body 3 in the cylinder axis X direction, corresponding to the annular concave portion 4 of the inner cylinder 1. Yes. The annular convex portion 6 is formed to be slightly larger than the annular concave portion 4 so that the compression rate thereof is high, and the volume thereof is set to be larger than the concave volume of the annular concave portion 4.

  Tapered surfaces 7 reaching the openings at both ends in the cylinder axis X direction are formed on both sides of the annular convex portion 6 on the inner periphery of the rubber elastic body 3, and the inner diameter of the rubber elastic body 3 is the same as that of the annular convex portion 6. It gradually increases from the vicinity toward both ends.

  As shown in FIG. 1A, the rubber bush B is integrally assembled by press-fitting the inner cylinder 1 into an outer cylinder 2 (such as an outer cylinder) to which the rubber elastic body 3 is molded and bonded. ing. That is, the inner cylinder 1 and the rubber elastic body 3 are connected in a non-bonded state.

  Specifically, one end of the inner cylinder 1 in the cylinder axis X direction is inserted from one opening of the outer cylinder or the like in the cylinder axis X direction. At this time, since the inclined surface 5 is formed on the inner cylinder 1 and the tapered surface 7 is formed on the rubber elastic body 3, it can be easily inserted. Then, when the inner cylinder 1 is further pushed after it hits the annular convex portion 6, the annular convex portion 6 is guided by the inclined surface 5 and can be smoothly pressed into the annular concave portion 4.

  In a state in which the annular convex portion 6 is press-fitted into the annular concave portion 4, the compression ratio of the annular convex portion 6 and its vicinity is increased. As a result, the axial straightness is increased and the operation stability is excellent. On the other hand, since the rubber elastic body 3 including the annular protrusion 6 has a large radial thickness in the middle of the cylinder axis direction and a sufficient compression allowance is obtained, even if the load from the axial direction changes greatly. It doesn't stiffen suddenly and is relatively comfortable to ride.

  Further, as described above, the compression ratio is high at the intermediate portion of the rubber elastic body 3 in the cylinder axis direction, while the compression ratio is reduced toward both ends in the cylinder axis direction, and the characteristics are soft against the twisting load. In addition, a gap is formed between the inner cylinder 1 and the rubber elastic body 3 so that the gap increases as it approaches the end. Therefore, for example, as shown by the arrow line in FIG. Even if it is twisted, the degree of interference between the rubber elastic body 3 and the inner cylinder 1 is reduced, so that the twisting rigidity is greatly reduced and the riding comfort is improved.

  In addition, tensile resistance due to adhesion does not occur, and the rubber elastic body 3 is easily displaced around the cylinder axis X. As a result, the torsional rigidity is also reduced, and the riding comfort when a torsional load is applied is improved. The ride comfort can be improved with respect to loads applied from various directions.

  Further, a part of the annular convex portion 6 protrudes from the annular concave portion 4, and for example, the rubber elastic body 3 after press-fitting indicated by a solid line with respect to the contour of the unloaded rubber elastic body 3 indicated by an imaginary line in FIG. As shown in the outline, the thickness of the rubber elastic body 3 around the annular convex portion 6 is increased in a pseudo manner, so that fatigue durability is improved against wear caused by twisting and twisting. Since the annular convex portion 6 and the annular concave portion 4 are connected by the concave-convex fitting over the entire circumference, there is no possibility that they are displaced in the direction of the cylinder axis X even if they are not bonded.

  As described above, the rubber bush B of the present embodiment has improved fatigue durability and can secure steering stability against a large load in the axial direction, but also has a compression allowance for the load in the axial direction. In addition to being sufficiently obtained, soft characteristics can be obtained even with complex external forces such as torsion and twisting, so that the ride comfort can be sufficiently ensured.

(Second Embodiment)
In FIG. 2, the longitudinal cross-sectional view of the rubber bush B of another preferable embodiment is shown. In the present embodiment, as shown in the drawing, the basic configuration is the same as that of the first embodiment except that the shape of the annular convex portion 6 and the shape of the inner cylinder 1 are different from those of the first embodiment. Therefore, the same reference numerals are assigned to the same members, and descriptions thereof are omitted.

  Specifically, in the present embodiment, the width of the annular convex portion 6 (length in the cylinder axis X direction) is substantially matched with the width of the annular concave portion 4 so that the annular convex portion 6 is fitted with no gap. On both side surfaces in the width direction, protrusions 6a projecting in an annular shape over the entire circumference were integrally formed. That is, the volume of the annular convex portion 6 fitted into the annular concave portion 4 is set to be larger than the volume of the annular concave portion 4 by the amount of the protrusion 6a.

  By doing so, the annular convex portion 6 itself can be made smaller as compared with the case without the protrusion 6a if the volume is the same, and accordingly, the annular convex portion 6 is bent and easily press-fitted. On the other hand, the degree of compression of the annular projection 6 in the cylinder axis X direction is increased by the amount of the protrusion 6a, and the displacement movement in the cylinder axis X direction is more reliably regulated, and a part of the annular projection 6 is Since it becomes easy to protrude from the annular recessed part 4, the fatigue durability of the rubber elastic body 3 can be improved more.

  Moreover, about the inner cylinder 1, the shape of the both sides of the annular recessed part 4 was devised. Specifically, a large-diameter portion 1b having a relatively large outer diameter is formed at an intermediate portion of the inner cylinder 1 in the cylinder axis X direction, while the outer diameter is relatively set at both ends in the cylinder axis X direction. A small-diameter portion d having a small diameter is formed, and an inclined portion 1c having an outer diameter gradually decreasing from the large-diameter portion 1b side toward the small-diameter portion 1d side is formed between the large-diameter portion 1b and the small-diameter portion 1d.

  And while setting the annular recessed part 4 to the substantially center part of the outer peripheral surface of the large diameter part 1b, the bottom face 4a of the annular recessed part 4 was set so that it might be larger diameter than the small diameter part 1d. Since the large-diameter portion 1b is longer in the cylinder axis X direction than the annular recess 4, the large-diameter portion 1b having a predetermined width spreads on both sides of the annular recess 4 in the cylinder axis X direction.

  By adopting such a configuration, the annular convex part 6 is vigorously inserted without contacting the inner cylinder 1 until it abuts against the inclined part 1c of the inner cylinder 1, and is guided into the inclined part 1c so as to be fitted into the annular concave part 4 at once. The inner cylinder 1 can be easily press-fitted into the outer cylinder or the like.

  Then, as shown in (b) of the figure, when the annular convex portion 6 is fitted into the annular concave portion 4, the ridge 6a is crushed and the annular convex portion 6 is compressed, and a part thereof is the annular concave portion. The rubber elastic body 3 is increased in thickness by protruding from 4. And since the peripheral site | part of the cyclic | annular convex part 6 with the increased thickness is received by the large diameter part 1b which spreads on both sides of the cyclic | annular recessed part 4 of the inner cylinder 1, while being connected, a wear state is suppressed and fatigue durability is suppressed. Will improve.

(Third embodiment)
FIG. 3 shows a longitudinal sectional view of a rubber bush B according to another preferred embodiment. In the present embodiment, the shape of the inner peripheral surface of the rubber elastic body 3 and the shape of the outer peripheral surface of the inner cylinder 1 are changed. Specifically, the inner peripheral surface of the rubber elastic body 3 was formed so as to extend in the direction of the cylinder axis X, and the annular convex portion 6 was formed in a rectangular cross section rising straight from there.

  On the other hand, the inner cylinder 1 has a large-diameter portion 1b and a small-diameter portion 1d as in the second embodiment, and the outer peripheral surface of the large-diameter portion 1b includes the annular recess 4 that opens there in the X direction. It was formed with a continuous corrugated curved surface.

  According to such a configuration, the inner cylinder 1 is easily pressed into the outer cylinder or the like by being guided by a smooth curved surface, and after the press-fitting, the annular convex portion 6 is also compressed or squeezed. Further, a load is uniformly applied to the rubber elastic body 3, the occurrence of local distortion of the annular convex portion 6 can be suppressed, and fatigue durability is improved. Further, since the volume of the annular convex portion 6 can be set to be relatively larger than the concave volume of the annular concave portion 4, it is possible to increase the axial rigidity and improve the fatigue durability.

  Each of the above-described embodiments merely illustrates some of the preferred embodiments of the rubber bush B of the present invention, and various other configurations are also included in the present invention.

  For example, in each of the embodiments described above, the annular recess 4 is provided on the inner cylinder 1 side, but may be provided on the outer cylinder 2 side. Specifically, taking the first embodiment as an example, as shown in FIG. 4, the rubber elastic body 3 is molded and bonded to the outer peripheral surface of the inner cylinder 1 made of a metal round pipe, and the outer peripheral surface of the rubber elastic body 3 is fixed. While the annular convex portion 6 is projected from the annular concave portion 4, the annular concave portion 4 is formed on the inner peripheral surface of the outer cylinder 2 correspondingly.

  And like the above-mentioned each embodiment, what is necessary is just to press-fit and connect the inner cylinder 1 in which the rubber elastic body 3 is molded and bonded to the outer cylinder 2 without bonding. Only the configuration of the first embodiment and the annular recess 4 and the like is reversed, and the same effect as that of the first embodiment can be obtained by this configuration. In this regard, the second embodiment and the third embodiment can be changed to the same configuration.

  In addition, the inner cylinder 1 of the first embodiment and the outer cylinder of the third embodiment (the outer cylinder 2 to which the rubber elastic body 3 is bonded), or the inner cylinder 1 of the third embodiment and the outside of the first embodiment. The combination of the inner cylinder 1 and the outer cylinder may be changed like a cylinder. The inner cylinder 1 is not limited to a forged product but may be a cast product. In each of the above embodiments, an example in which a gap exists between the rubber elastic body 3 and the inner cylinder 1 is shown, but the gap may not be present.

It is a longitudinal cross-sectional view of the rubber bush B of 1st Embodiment. (A) schematically shows the state before assembly, and (b) schematically shows the state after assembly. It is a longitudinal cross-sectional view of the rubber bush B of 2nd Embodiment. (A) schematically shows the state before assembly, and (b) schematically shows the state after assembly. It is a longitudinal cross-sectional view of the rubber bush B of 3rd Embodiment. (A) schematically shows the state before assembly, and (b) schematically shows the state after assembly. It is a longitudinal cross-sectional view of the rubber bush B of another embodiment. (A) schematically shows the state before assembly, and (b) schematically shows the state after assembly.

Explanation of symbols

B Rubber bush X Tube shaft 1 Inner tube 1b Large diameter portion 1c Inclined portion 1d Small diameter portion 2 Outer tube 3 Rubber elastic body 4 Annular recess 6 Annular protrusion 6a Projection

Claims (7)

A rubber bush comprising an inner cylinder, an outer cylinder surrounding the outer periphery thereof, and a substantially cylindrical rubber elastic body connecting these,
Either one of the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder is formed with an annular recess over the entire circumference at an intermediate portion in the cylinder axis direction, An annular convex portion is formed on the peripheral surface or the outer peripheral surface,
The annular convex portion is press-fitted into the annular concave portion and connected in a non-adhered state, and the compression rate of the rubber elastic body in the annular convex portion is higher than at least the end portion in the cylinder axis direction. Characteristic rubber bush. The rubber bush according to claim 1,
A rubber bush, wherein the annular recess is formed on the outer peripheral surface of the inner cylinder, and the annular convex portion is formed on the inner peripheral surface of the rubber elastic body. The rubber bush according to claim 2,
A rubber bush characterized in that an inner diameter of the rubber elastic body is formed so as to gradually increase from the vicinity of the annular convex portion toward both end sides. In the rubber bush according to claim 2 or 3,
A rubber bush characterized in that the outer diameter of the inner cylinder is formed so as to gradually decrease from the vicinity of the annular recess toward both ends in the cylinder axis direction. In the rubber bush according to claim 2 or 3,
The inner cylinder has a large-diameter portion having a relatively large outer diameter at an intermediate portion in the cylinder axis direction, and a small-diameter portion having a relatively small outer diameter on both ends in the cylinder axis direction, and these large diameters. Between the portion and the small-diameter portion, an inclined portion that gradually decreases in outer diameter from the large-diameter portion side toward the small-diameter portion side is formed,
A rubber bush characterized in that the annular recess is opened on the outer peripheral surface of the large-diameter portion, and the bottom surface has a larger diameter than the small-diameter portion. In the rubber bush according to claim 2 or 3,
The inner cylinder has a large diameter portion having a relatively large outer diameter at an intermediate portion in the cylinder axis direction, while small diameter portions having a relatively small outer diameter are formed on both end sides in the cylinder axis direction, respectively.
A rubber bush, wherein the annular recess is opened on an outer peripheral surface of the large diameter portion, and the outer peripheral surface of the large diameter portion including the annular recess is formed by a curved surface continuous in the cylinder axis direction. The rubber bush according to any one of claims 2 to 6,
A rubber bush, characterized in that annular protrusions over the entire circumference are formed on both side surfaces in the cylindrical axis direction on the annular convex portion of the rubber elastic body.

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