sliding bushing

Abstract

The present application provides a new structure of sliding bushing which can advantageously set the hard elastic property in the axial perpendicular direction and the soft elastic property in the twisting direction and prying direction. The present application is a sliding bushing 10 which allows the sliding of an inner shaft member 12 relative to a main body rubber elastic body 16, the inner shaft member 12 is provided with a protruding portion 18 in the middle of the axial direction, and a cloth-like sliding inner liner 34 woven is arranged between the inner shaft member 12 and the main body rubber elastic body 16 without being bonded to the inner shaft member 12 and being able to slide relative to the inner shaft member 12. In the sliding inner liner 34, the portion arranged at the outer periphery of the large diameter portion relative to the protruding portion 18 of the inner shaft member 12 is provided with a thick hole portion 44 in which the woven hole 36 is thicker than the portion arranged at the outer periphery of the small diameter portion 20 relative to the axial direction on both sides of the large diameter portion 18.

Description

Technical Field

[0001] The present invention relates to bushings, such as suspension bushings for motor vehicles, and more particularly to sliding bushings that allow sliding of an inner shaft member relative to a main rubber elastomer. Background Technology

[0002] Previously, bushings for motor vehicle suspension bushings, such as those disclosed in Japanese Patent Application Publication No. 2010-159860 (Patent Document 1), were known. The bushing in Patent Document 1 has a structure in which the shaft member and the outer cylinder are connected by a rubber-like elastomer.

[0003] In addition, when it is necessary to balance the high elasticity in the vertical direction of the shaft and the low elasticity in the torsional direction, as in the case of suspension bushings, the following structure can be adopted as shown in Patent Document 1: a first bulge is provided on the shaft member and a second bulge is provided on the outer cylinder, so that the first bulge and the second bulge are arranged concentrically.

[0004] However, in suspension bushings and the like, there is sometimes a need for low elasticity characteristics relative to torsional input. In this case, setting the shaft member to be non-adhesive relative to the rubber-like elastomer, thereby allowing relative rotation between the shaft member and the rubber-like elastomer, can achieve the required low elasticity characteristics in the torsional direction.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-159860 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, the inventors have identified the following new problem through investigation: In the structure of Patent Document 1, if the shaft member is simply not bonded to the rubber-like elastomer and torsional displacement (rotation) is allowed, there is a risk that the required characteristics cannot be met if the high elasticity in the vertical direction of the shaft cannot be set and a harder characteristic is pursued in the vertical direction of the shaft.

[0010] The problem to be solved by the present invention is to provide a novel sliding bushing with a structure in which the hard elastic properties in the vertical direction of the shaft and the soft elastic properties in the torsional and prying directions can be advantageously set.

[0011] means for solving problems

[0012] Hereinafter, preferred embodiments for understanding the present invention will be described. However, the embodiments described below are illustrative and can be appropriately combined with each other. Furthermore, the multiple constituent elements described in each embodiment can be understood and used as independently as possible, and can also be appropriately combined with any constituent element described in other embodiments. Therefore, the present invention is not limited to the embodiments described below, and various other embodiments can be implemented.

[0013] The first type is a sliding bushing having an inner shaft member and an outer cylinder member connected by a main body rubber elastomer and allowing the inner shaft member to slide relative to the main body rubber elastomer. The inner shaft member has a protrusion at the middle of the axial direction, and a woven fabric-like sliding liner is non-adhesive to the inner shaft member and slidably disposed between the inner shaft member and the main body rubber elastomer. In the sliding liner, a portion disposed on the outer periphery of the large-diameter portion relative to the protrusion of the inner shaft member has a coarse-hole portion with woven holes that are coarser than the portions disposed on the outer periphery of the small-diameter portions on both sides of the large-diameter portion in the sliding liner.

[0014] According to the sliding bushing configured in this manner, the inner shaft member and the main rubber elastomer are designed to be non-adhesive at least in the portion where the sliding bushing is disposed, and the inner shaft member is provided with a protrusion, thereby achieving low elasticity due to the reduction of compressive elasticity component in response to input in the prying direction. Furthermore, the inner shaft member and the main rubber elastomer are designed to be non-adhesive in the portion where the sliding bushing is disposed, thereby achieving low elasticity due to the sliding of the inner shaft member and the main rubber elastomer in response to input in the torsional direction. Moreover, because the sliding resistance between the inner shaft member and the main rubber elastomer is smaller due to the sliding bushing, low elasticity is more advantageously achieved in both the prying and torsional directions.

[0015] Furthermore, the portion of the sliding liner that is installed on the large-diameter part of the protrusion can easily follow the shape of the outer peripheral surface of the protrusion through the coarse-pore portion of the weave. As a result, because the sliding liner can be easily positioned along the outer peripheral surface of the inner shaft member, the gap between the inner shaft member and the sliding liner is suppressed. Therefore, it is possible to prevent the main rubber elastomer from entering between the sliding liner and the inner shaft member, thus ensuring sliding performance, and also preventing the sliding liner from deforming into unexpected shapes such as wrinkles.

[0016] Furthermore, in the sliding liner, the braided holes in the portions installed on the smaller diameter portions on both sides of the large diameter portion are smaller than the braided holes in the portions installed on the large diameter portions of the protrusions. In the portions installed in the smaller diameter portions with smaller braided holes, the deformation of the main rubber elastomer is strongly constrained by the sliding liner, thus limiting the axial outward deformation of the main rubber elastomer. Therefore, during input in the axially perpendicular direction, the axial outward retraction of the main rubber elastomer is suppressed, and the main rubber elastomer is efficiently compressed, thereby exhibiting high elasticity. In this way, by setting the size of the braided holes formed in the sliding liner to be larger in the portion installed in the large diameter portion and smaller in the portion installed in the small diameter portion, the installability of the sliding liner relative to the inner shaft member with the protrusions is improved, while high elasticity in the axially perpendicular direction is achieved.

[0017] The second method is based on the sliding bushing described in the first method, wherein a cut is formed in the coarse hole portion of the sliding liner.

[0018] According to the sliding bushing configured in this manner, the cut of the sliding inner liner is pushed out by the large-diameter portion of the protrusion, thereby easily allowing the coarse-hole portion to follow the deformation of the protrusion through the cut. Furthermore, in this method, the cut is pushed out and opens, thus enabling the cut to function as a coarse-hole portion. Therefore, by appropriately adjusting the size and manner of the cut, the degree of freedom in adjusting the elastic properties of the main rubber elastomer can be increased.

[0019] The third method is based on the sliding bushing described in the first or second method, wherein the sliding liner is loosely woven in the coarse-hole portion.

[0020] By setting a sliding bushing with a structure according to this method, and by changing the weaving method, weaving method, etc. of the sliding inner lining to set a part that is pre-loosely woven, the conformity of the coarse hole portion to the shape of the protrusion portion can be improved.

[0021] The fourth method is based on the sliding bushing described in any of the first to third methods, wherein the sliding inner liner is composed of two segmented inner liners that are axially joined together on the inner shaft member, and the ends of the joining sides of the two segmented inner liners are arranged on the outer periphery of the large diameter portion of the protrusion of the inner shaft member to form the coarse hole portion.

[0022] Since the sliding bushing is configured according to this method, the coarse-hole portion is located at the end of the dividing liner, so the coarse-hole portion caused by the variation of the weaving or stitching can easily be formed.

[0023] The fifth method is based on the sliding bushing described in any of the first to fourth methods, wherein the sliding inner liner is disposed between the inner shaft member and the entire overlapping surface of the main rubber elastomer.

[0024] According to the sliding bushing configured in accordance with this method, the frictional resistance during sliding between the inner shaft member and the main rubber elastomer is more advantageously reduced by the sliding bushing disposed between the entire overlapping surface of the inner shaft member and the main rubber elastomer, and the low elasticity in the prying and torsional directions is more effectively achieved.

[0025] The sixth method is based on the sliding bushing described in any of the first to fourth methods, wherein the overlapping surface of the inner shaft member and the main body rubber elastomer extends to a position axially outer than the sliding inner liner.

[0026] According to the sliding bushing configured in this manner, the inner shaft member and the main rubber elastomer overlap directly on the outer side of the axial direction without passing through the sliding bushing. This reduces the axial sliding property of the main rubber elastomer relative to the inner shaft member on the outer side compared to the sliding bushing. Therefore, during input in the prying or torsional directions, the low elasticity resulting from the low friction of the sliding bushing is achieved in the central axial region where the elastic properties are most significant. Simultaneously, during input in the axially perpendicular direction, the outward retraction of the main rubber elastomer is restricted due to its direct overlap with the inner shaft member, enabling high elasticity in the axially perpendicular direction.

[0027] The seventh method is based on the sliding bushing described in any of the first to sixth methods, wherein,

[0028] The outer cylinder member has two axially oriented outer ends that form small-diameter tapered portions, the minimum inner diameter of which is smaller than the maximum outer diameter of the protrusion in the inner cylinder member.

[0029] According to the sliding bushing configured in this manner, the axial outward deformation of the main rubber elastomer is restricted by the tapered portion of the outer cylinder member, enabling the setting of a stiffer elastic characteristic in the axially perpendicular direction. Furthermore, for axial input, if the main rubber elastomer is compressed between the protrusion and the tapered portion, a stiffer elastic characteristic can also be set in the axial direction.

[0030] Invention Effects

[0031] According to the present invention, the hard elasticity characteristics in the vertical direction of the shaft and the soft elasticity characteristics in the torsional and prying directions can be advantageously set. Attached Figure Description

[0032] Figure 1This is a longitudinal sectional view showing the suspension bushing as a first embodiment of the present invention.

[0033] Figure 2A It constitutes Figure 1 The side view of the sliding inner liner of the suspension bushing shown.

[0034] Figure 2B It is Figure 2A The side view shown is of the sliding liner installed in the inner shaft member.

[0035] Figure 3A This is a side view of the sliding inner liner that constitutes the sliding bushing according to the second embodiment of the present invention.

[0036] Figure 3B It is Figure 3A The side view shown is of the sliding liner installed in the inner shaft member.

[0037] Figure 4A This is a side view of the sliding inner liner that constitutes the sliding bushing according to the third embodiment of the present invention.

[0038] Figure 4B It is Figure 4A The side view shown is of the sliding liner installed in the inner shaft member.

[0039] Figure 5 This is a longitudinal sectional view showing the suspension bushing as a fourth embodiment of the present invention.

[0040] Figure 6 This is a longitudinal sectional view showing a suspension bushing as another embodiment of the present invention. Detailed Implementation

[0041] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0042] exist Figure 1 In the present invention, a first embodiment of a sliding bushing configured according to the structure of the present invention is shown, namely a suspension bushing 10 for a motor vehicle. The suspension bushing 10 has a structure in which an inner shaft member 12 and an outer cylinder member 14 are elastically connected by a main body rubber elastomer 16.

[0043] The inner shaft member 12 is, for example, a highly rigid component made of metal, and is generally configured as a small-diameter cylindrical shape. The inner shaft member 12 may be a solid rod or the like, in which case, for example, a fixing structure that can be provided at both ends of the axial direction to fix it to the suspension arm or the like.

[0044] In the inner shaft member 12, a protrusion 18 is provided at the central portion in the axial direction. The protrusion 18 is a large-diameter portion that protrudes outward. The protrusion 18 has a generally spherical outer peripheral surface that protrudes outward. In the protrusion 18 of this embodiment, the inner peripheral surface is provided as a curved surface corresponding to the outer peripheral surface, and the thickness is provided as approximately constant throughout the axial direction. However, the thickness of the protrusion can also vary in the axial direction; for example, the inner peripheral surface can also be provided as a cylindrical surface that extends straight along the axial direction.

[0045] In the inner shaft member 12, the portion axially outer of the protrusion 18 is provided as a small-diameter cylindrical portion 20, 20. The outer diameter of the small-diameter cylindrical portion 20 is smaller than that of the protrusion 18, and it extends axially outward from the axial end of the protrusion 18. At the axial end opposite to the protrusion 18 in each small-diameter cylindrical portion 20, a protrusion 22 protruding outward is provided around the entire circumference. In the small-diameter cylindrical portion 20 of the inner shaft member 12, a recess 24 opening on the outer circumference is provided around the entire circumference between the protrusion 22 and the protrusion 18.

[0046] The outer cylinder member 14, like the inner shaft member 12, is configured as a highly rigid component. Compared to the inner shaft member 12, the outer cylinder member 14 is configured as a thin-walled, large-diameter, approximately cylindrical shape, and has a shorter axial length. In the outer cylinder member 14, the central portion along the axial direction is configured as a cylindrical portion 26 extending linearly along the axial direction, and tapered portions 28, 28 are provided on both sides of the cylindrical portion 26, inclined inwards towards the outer side of the axial direction. The tapered portions 28 can be inclined at a constant angle relative to the axial direction, or the inclination angle can vary axially; in this embodiment, the inclination angle relative to the axial direction decreases towards the outer side of the axial direction. The tapered portions 28 can be pre-formed during the formation of the outer cylinder member 14, or they can be formed, for example, during the diameter reduction machining of the outer cylinder member 14 described below.

[0047] In the outer cylinder component 14, tapered portions 28, 28 are provided on both axial sides of the cylindrical portion 26. Figure 1 The longitudinal section shown has a cross-sectional shape that is concave towards the inner circumference as a whole. In the outer cylinder member 14, the axial dimension of the cylindrical portion 26 is smaller than the axial length dimension of the protrusion 18, and the overall axial length dimension of the outer cylinder member 14 is larger than the axial length dimension of the protrusion 18. It should be noted that the cylindrical portion 26 is not necessary in the outer cylinder member 14; for example, an outer cylinder member that is integrally curved in the longitudinal section can also be used.

[0048] The inner shaft member 12 is inserted into the inner circumference of the outer cylinder member 14, and the inner shaft member 12 and the outer cylinder member 14 are arranged concentrically. The inner shaft member 12 protrudes axially to both sides relative to the outer cylinder member 14. The two axial ends of the outer cylinder member 14 are located on the outer sides axially than the protrusions 18 of the inner shaft member 12. The protrusions 18 located on the inner side of the outer cylinder member 14 in both the axial and radial directions are arranged to be surrounded by the outer cylinder member 14 at a predetermined distance. The radial distance between the inner shaft member 12 and the outer cylinder member 14 is set to be the smallest at the axial center where the protrusions 18 and the cylindrical portion 26 are opposite each other, and gradually increases towards the outer side axially at the protrusions 18. The minimum inner diameter R1 of the tapered portion 28 is smaller than the maximum outer diameter R2 of the protrusions 18. More preferably, the minimum inner diameter R3 of the tapered portion 28 at the axial outer end of the portion on which the main rubber elastomer 16 is fixedly installed is smaller than the maximum outer diameter R2 of the protrusion 18, and the main rubber elastomer 16 is continuously provided axially between the axially opposing surfaces of the protrusion 18 and the tapered portion 28.

[0049] The inner shaft member 12 and the outer cylinder member 14 are elastically connected by a main body rubber elastomer 16. The main body rubber elastomer 16 is cylindrical in shape and is configured to connect the opposing surfaces of the outer peripheral surface of the inner shaft member 12 and the inner peripheral surface of the outer cylinder member 14. A fixing mounting portion 30, which fills the recess 24 of the inner shaft member 12, is provided at the inner peripheral end of the main body rubber elastomer 16. In this embodiment, the main body rubber elastomer 16 is configured to be non-adhesive to the inner shaft member 12 and is formed as an integral vulcanized molded part having the outer cylinder member 14. The non-adhesive inner shaft member 12 and the main body rubber elastomer 16 are allowed to slide in the prying direction and the torsional direction.

[0050] The main body rubber elastomer 16 is disposed in the axial region spanning the outer peripheral surface of the protrusion 18 in the inner shaft member 12 and the outer peripheral surface of the small-diameter cylindrical portions 20, 20. The axial length of the portion of the main body rubber elastomer 16 disposed to directly fill the radially opposing surfaces of the inner shaft member 12 and the outer cylindrical member 14 is preferably an axial length extending to the small-diameter cylindrical portions 20, 20 extending axially from the protrusion 18 to both sides. In the portion of the main body rubber elastomer 16 disposed to directly fill the radially opposing surfaces of the inner shaft member 12 and the outer cylindrical member 14, the radial thickness at both axial ends is larger than that at the axial center. However, the main body rubber elastomer 16 may also extend axially with a substantially constant radial thickness.

[0051] On the axial end face of the main rubber elastomer 16, concave recesses 32, 32 are formed throughout the entire circumference, opening axially between the inner shaft member 12 and the outer cylinder member 14 in the radial direction. The bottoms of the recesses 32, 32 reach the outer periphery of the protrusion 18. There are no particular limitations on the depth, size, shape, etc., of the recesses 32. For example, the depth of the recesses 32 may be such that it does not reach the outer periphery of the protrusion 18 from the axial end face of the main rubber elastomer 16. Alternatively, the recesses 32 may not be provided.

[0052] By performing a diameter reduction process, such as deep drawing, on the outer cylinder member 14 after the vulcanization molding of the main rubber elastomer 16, the tensile stress caused by thermal shrinkage acting on the main rubber elastomer 16 is reduced, thereby improving the durability of the main rubber elastomer 16. Furthermore, by significantly reducing the diameter of the axial end of the outer cylinder member 14 during the diameter reduction process, tapered portions 28, 28 are formed in the outer cylinder member 14. This allows the inner shaft member 12 to be inserted into the outer cylinder member 14 before the main rubber elastomer 16 is formed, and ensures that the minimum inner diameter R1 of the tapered portions 28, 28 is smaller than the maximum outer diameter R2 of the protrusion 18 after the main rubber elastomer 16 is formed. Moreover, the loosening of the inner shaft member 12 relative to the outer cylinder member 14 is prevented by the indirect engagement of the protrusion 18 and the tapered portions 28, 28 via the main rubber elastomer 16. In addition, the minimum inner diameter R3 of the portion in the cones 28, 28 where the main rubber elastomer 16 is fixedly installed is smaller than the maximum outer diameter R2 of the protrusion 18, so that the hard elasticity characteristics of the main rubber elastomer 16 can be obtained when the axial vibration input is applied, resulting from the compression of the main rubber elastomer 16 between the protrusion 18 and the cones 28, 28.

[0053] It should be noted that the outer cylinder component 14 and the main rubber elastomer 16 are vulcanized and bonded together. No sliding layer based on a liner, coating, or the like is provided between the overlapping surfaces of the outer cylinder component 14 and the main rubber elastomer 16. Therefore, when the outer cylinder component 14 is reduced in diameter, no adverse conditions such as wrinkling of the sliding layer will occur. The main rubber elastomer 16 is fixedly installed across the inner circumferential surfaces of the cylindrical portion 26 and the conical portions 28, 28 within the outer cylinder component 14.

[0054] A sliding liner 34 is disposed between the overlapping surfaces of the inner shaft member 12 and the main rubber elastomer 16. The sliding liner 34 is a fabric-like weave (woven material or fabric) formed by knitting or weaving low-friction threads into it, and the weave holes or woven openings 36 that constitute the gaps (weave holes) between the fibers of the weave are formed in a generally continuous state. Figure 2A As shown, the sliding liner 34 is generally cylindrical. However, the sliding liner 34 can also be formed as a rectangular sheet, rolled up and attached to the inner shaft member 12 to be generally cylindrical.

[0055] The sliding liner 34 is, for example, a PTFE (polytetrafluoroethylene) liner formed by weaving low-friction yarns containing fluoropolymer fibers, resulting in a low coefficient of friction on its surface. The yarns constituting the sliding liner 34 can also be blended yarns or woven yarns, formed by appropriately blending fluoropolymer fibers with fibers made of other materials (e.g., synthetic fibers other than fluoropolymer fibers, glass fibers). Alternatively, the sliding liner 34 can be formed by impregnating the braid with synthetic resin. The yarns constituting the sliding liner 34 may not be stretchable; for example, the materials of blended or woven fibers can be appropriately selected to impart stretchability.

[0056] In the sliding liner 34, a slit 38 is formed in the central portion along the axial direction. There are no particular limitations on the number, arrangement, or shape of the slits 38. In this embodiment, multiple slits 38 extending linearly along the axial direction are formed and separated from each other in the circumferential direction. For example, the slits 38 may extend axially while being inclined circumferentially, or they may extend circumferentially, or they may bend or fold and extend. Alternatively, the slits 38 may be configured as slits with a pre-opened width.

[0057] like Figure 2B As shown, the sliding inner liner 34 is installed in an inserted state on the inner shaft member 12. The sliding inner liner 34 is inserted externally without being bonded to the inner shaft member 12, allowing sliding relative to the inner shaft member 12 in both the prying and torsional directions. The woven fabric-like sliding inner liner 34 deforms along the outer peripheral surface of the inner shaft member 12, thereby pushing the weave or perforation 36 outwards by the inner shaft member 12. In the sliding inner liner 34, the two ends inserted into the axial direction of the small-diameter cylindrical portions 20, 20 are configured as fine-hole portions 42 with finer weave or perforations 36, and the central portion inserted into the axial direction of the protrusion 18 is configured as a coarser-hole portion 44 with coarser weave or perforations 36. It should be noted that, in this embodiment, in the inner shaft member 12, the large-diameter portion is formed by the entire axial direction of the protrusion 18, and the small-diameter portion is formed by the portion that deviates the protrusion 18 axially outwards.

[0058] In the sliding liner 34, the coarse-perforated portion 44 with larger weave or stitch 36 allows for greater deformation than the fine-perforated portion 42. Therefore, when the sliding liner 34 is installed onto the inner shaft member 12, the coarse-perforated portion 44 deforms along the surface of the protrusion 18, and the sliding liner 34 is positioned along the surface of the inner shaft member 12, making it less prone to wrinkling or loosening. In this embodiment, as... Figure 2A As shown, a notch 38 is provided in the coarse hole portion 44. When the sliding inner liner 34 is installed into the inner shaft member 12, as... Figure 2B As shown, the opening of the cut 38 expands in the circumferential direction, which facilitates deformation along the protrusion 18 in the axial central portion of the sliding liner 34.

[0059] In this embodiment, a cutout 38 is provided in the coarse hole portion 44 of the axial central portion constituting the sliding liner 34. The cutout 38 is pushed out by the protrusion 18, thereby allowing greater diameter expansion deformation in the coarse hole portion 44 of the axial central portion constituting the sliding liner 34.

[0060] It should be noted that in the sliding liner 34, the perforations or weave holes 36 are also extended in the portion that is inserted into the small-diameter cylindrical portions 20, 20, and the sliding liner 34 is tightly attached to the outer peripheral surface of the small-diameter cylindrical portions 20, 20 without gap. However, when the sliding liner 34 is disposed on the inner shaft member 12, the expansion deformation of the axial central portion including the portion that is inserted outward into the protrusion 18 is greater than the expansion deformation of the axial end portions that are inserted outward into the small-diameter cylindrical portions 20, 20, thereby creating a density of weave between the fine-hole portion 42 and the coarse-hole portion 44.

[0061] The sliding liner 34, mounted on the inner shaft member 12, is disposed together with the inner shaft member 12 into the cavity of a molding die (not shown) during the vulcanization molding of the main rubber elastomer 16. Then, the main rubber elastomer 16 is formed on the outer peripheral side of the sliding liner 34, thereby disposing the sliding liner 34 between the inner shaft member 12 and the main rubber elastomer 16.

[0062] In this embodiment, the sliding liner 34 is configured to cover the entire axial length of the outer peripheral surface of the inner shaft member 12. Therefore, the sliding liner 34 is provided across the entire overlapping surface of the inner shaft member 12 and the main rubber elastomer 16. In particular, in this embodiment, the sliding liner 34 extends to the outer axial direction, offsetting the overlapping surface of the inner shaft member 12 and the main rubber elastomer 16, and the outer peripheral surfaces of the protrusions 22, 22 are covered by the sliding liner 34. However, the axial length of the sliding liner 34 does not necessarily have to be the same as the axial length of the inner shaft member 12; for example, it can also be the same as the axial length of the overlapping surface of the inner shaft member 12 and the main rubber elastomer 16.

[0063] The main rubber elastomer 16 is vulcanized in a state where it enters the weave or perforation 36 of the sliding liner 34 and / or in a state of close contact with the uneven surface of the braided yarn. Because the sliding liner 34 is formed using a low-friction material, it is difficult to bond it to the main rubber elastomer 16. However, through mechanical bonding via entry into the weave or perforation 36, the sliding liner 34 is substantially fixedly mounted to the inner circumferential surface of the main rubber elastomer 16. In this embodiment, the anchoring effect can also be achieved by the main rubber elastomer 16 entering relative to the cutout 38 formed in the coarse hole portion 44. It should be noted that bonding treatment or similar processes can also be performed on the outer circumferential surface of the sliding liner 34.

[0064] The sliding liner 34 restricts the expansion and contraction deformation within the smaller perforations 42 of the weave or stitch 36. Therefore, at both axial ends of the main rubber elastomer 16 fixedly mounted in the perforated portion 42, the strong deformation constraint force provided by the sliding liner 34 restricts the elastic deformation outward in the axial direction.

[0065] On the other hand, the sliding liner 34 allows for greater deformation in the larger coarse-hole portion 44 of the knitted or woven perforation 36 than in the fine-hole portion 42. Therefore, the axial central portion of the main rubber elastomer 16 fixedly mounted to the coarse-hole portion 44 is more likely to allow elastic deformation than the axial end portions fixedly mounted to the fine-hole portion 42.

[0066] Furthermore, a slit 38 extending axially is formed in the sliding liner 34, which has a roughly constant radial dimension relative to its initial shape. Through the installation of the inner shaft member 12, the axially central portion of the sliding liner 34 expands due to the large-diameter protrusion 18. The expansion dimension (circumferential opening width) of the slit 38 is larger in the large-diameter portion at the axial center of the protrusion 18, and smaller in the small-diameter cylindrical portions 20, 20 that become small-diameter portions on both sides of the axial direction. Therefore, according to the slit 38, the constraint effect on the main rubber elastomer 16 provided by the sliding liner 34 functions more effectively in the small-diameter cylindrical portions 20, 20 located on both sides of the protrusion 18.

[0067] The suspension bushing 10 configured as described above connects the vehicle body and the suspension arm for vibration damping by mounting the inner shaft member 12 to the vehicle body side (not shown) and the outer cylinder member 14 to the suspension arm side (not shown).

[0068] If a vibration in the axial direction (radial direction) is input between the inner shaft member 12 and the outer cylinder member 14, the main rubber elastomer 16 is compressed in the axial direction between the inner shaft member 12 and the outer cylinder member 14, thus exhibiting the hard elasticity characteristics brought about by the compression elastic component. In particular, because the inner shaft member 12 is provided with a protrusion 18, the radial thickness of the main rubber elastomer 16 is smaller on the outer periphery of the protrusion 18, so the hard elasticity characteristics can be obtained through the compression of the main rubber elastomer 16.

[0069] Because the main rubber elastomer 16 is not bonded to the inner shaft member 12, it deforms axially outward according to the shape of the outer peripheral surface of the protrusion 18 when compressed in the axially perpendicular direction. Here, the deformation of the axial end of the main rubber elastomer 16 is limited by the fine hole portion 42 of the sliding liner 34. As a result, the main rubber elastomer 16 is difficult to deform axially outward, preventing the main rubber elastomer 16 from retreating axially outward, thereby effectively utilizing the hard elasticity characteristics brought about by compression in the axially perpendicular direction.

[0070] Furthermore, because the two axial ends of the outer cylinder member 14 are provided with tapered portions 28, 28, the outward retraction of the outer peripheral portion of the main rubber elastomer 16 is suppressed by the tapered portions 28, 28. As a result, the hard elasticity properties can be set more effectively in the axially perpendicular direction.

[0071] If a vibration in the prying direction is input between the inner shaft member 12 and the outer cylinder member 14, the main rubber elastomer 16 undergoes shear deformation between the protrusion 18 of the inner shaft member 12 and the outer cylinder member 14, resulting in a smaller compressive elastic component and thus low elasticity in the prying direction. Because the inner shaft member 12 and the main rubber elastomer 16 are designed to slide without adhesion, the shear elastic component is also reduced, and the elastic constant in the prying direction is even smaller. It should be noted that a recess 32 is provided on the axially outer portion of the main rubber elastomer 16, further reducing the compressive elastic component of the main rubber elastomer 16 during the prying displacement of the inner shaft member 12 and the outer cylinder member 14.

[0072] If a torsional vibration is input between the shaft member 12 and the outer cylinder member 14, the main rubber elastomer 16 undergoes shear deformation between the protrusion 18 of the inner shaft member 12 and the outer cylinder member 14. The compressive elastic component is small, thus achieving low elasticity in the torsional direction. Because the inner shaft member 12 and the main rubber elastomer 16 are designed to be non-adhesive and able to slide, the shear elastic component is also reduced, and the elastic constant in the torsional direction is even smaller.

[0073] A sliding liner 34 is disposed between the overlapping surfaces of the inner shaft member 12 and the main rubber elastomer 16, reducing the frictional resistance during sliding between the outer peripheral surface of the inner shaft member 12 and the inner peripheral surface of the main rubber elastomer 16. This allows for more effective achievement of low elasticity in both the prying and torsional directions. In this embodiment, because the sliding liner 34 is provided along the entire axial length of the inner shaft member 12, the improved sliding properties between the inner shaft member 12 and the main rubber elastomer 16 brought about by the sliding liner 34 are effectively achieved, further enhancing the low elasticity of both prying and torsional elasticity.

[0074] By forming a sliding layer between the overlapping surfaces of the inner shaft member 12 and the main rubber elastomer 16 by means of a sliding liner 34, a sliding layer can be simply provided compared to, for example, providing a sliding layer by applying a low-friction sliding coating to the outer peripheral surface of the inner shaft member 12.

[0075] exist Figure 3A The figure shows a sliding inner liner 50 constituting a sliding bushing according to a second embodiment of the present invention. The sliding inner liner 50, like the sliding inner liner 34 of the first embodiment, is a woven fabric and is generally cylindrical in shape. In the following description, components and parts substantially the same as those in the described embodiment are labeled with the same reference numerals, and thus descriptions are omitted.

[0076] In the sliding liner 50, the woven holes or weave holes 52a at both axial ends are different in size from the woven holes or weave holes 52b at the axial center. The axial ends are configured as fine-hole portions 42 with finer woven holes 52a, while the axial center is configured as coarser-hole portions 44 with coarser woven holes 52b. The coarser-hole portions 44 can be formed, for example, by partially loosely weaving in the sliding liner 50 by varying the weaving or weave pattern. In this embodiment, the coarser-hole portions 44, which are loosely woven compared to the fine-hole portions 42, have larger woven holes 52b than the woven holes 52a of the fine-hole portions 42 in their stand-alone state before installation into the inner shaft member.

[0077] In the sliding liner 50, in Figure 3A In the single-unit state before installation of the inward-facing shaft member, the woven holes 52b in the loosely woven coarse-hole portion 44 are larger than the woven holes 52a in the fine-hole portion 42. Therefore, in the sliding liner 50, the extension caused by the deformation of the coarse-hole portion 44 is allowed in the loosely woven axial central portion, in... Figure 3B In the state shown where the inner shaft member is installed, the diameter of the central portion in the axial direction is larger than that of the two end portions. As a result, the sliding liner 50 can deform to follow the shape of the outer peripheral surface of the inner shaft member with protrusions, making it difficult to form a gap between the outer peripheral surface of the inner shaft member and the sliding liner 50. For example, during the molding of the main rubber elastomer, it is difficult for unexpected deformations such as wrinkling or bending to occur in the sliding liner 50. It should be noted that the sliding liner 50 can be formed in a shape corresponding to the outer peripheral surface of the inner shaft member in which the diameter of the coarse hole 44 is pre-made to be larger than that of the fine hole 42. In this case, it is not necessary for the coarse hole 44 to be pushed out by the protrusion of the inner shaft member.

[0078] In the sliding bushing using the sliding inner liner 50 of the above embodiment, similarly to the suspension bushing 10 of the first embodiment, it is possible to achieve a balance between low elastic constant in the prying and torsional directions and high elastic constant in the axis perpendicular direction.

[0079] exist Figure 4A The slide bushing 60, constituting a slide bushing according to a third embodiment of the present invention, is shown in the diagram. The slide bushing 60 is composed of mutually independent segmented bushings 62a and 62b. The segmented bushings 62a and 62b are arranged opposite each other axially in relation to the inner shaft member 12, and are mounted on opposite sides of the inner shaft member 12. In this embodiment, the segmented bushings 62a and 62b are arranged in a slightly separated butt joint state axially, but they can also be arranged in a state of contact axially. It should be noted that since the segmented bushings 62a and 62b in this embodiment are common components arranged opposite each other axially, their structure is described as segmented bushing 62.

[0080] The outer axial portion of the segmented inner liner 62 of the small-diameter cylindrical portion 20 installed on the inner shaft member 12 is configured as a fine-hole portion 42 with finer weave holes or knitting holes 52a. In addition, the inner axial portion of the segmented inner liner 62 of the protrusion 18 installed on the inner shaft member 12 is configured as a coarse-hole portion 44 with coarser weave holes or knitting holes 52b.

[0081] In the segmented liner 62, in its single-unit state before installation onto the inner shaft member 12, the woven holes 52b in the coarse-hole portion 44 are larger than the woven holes 52a in the fine-hole portion 42. Therefore, the segmented liner 62 allows for the extension resulting from the deformation of the coarse-hole portion 44 in its axially inner portion. Figure 4B In the state shown where the inner shaft member is installed, it closely follows the outer peripheral surface of the inner shaft member with the protrusion. Then, by installing a pair of segmented inner liners 62a and 62b on both axial sides of the inner shaft member, a sliding inner liner 60 corresponding to the shape of the outer peripheral surface of the inner shaft member can be obtained. In the segmented inner liners 62a and 62b, the woven hole of the inner portion that becomes the axial mating side is set as a coarser coarse hole portion 44.

[0082] In the sliding bushing using the sliding inner liner 34 of this embodiment, similarly to the suspension bushing 10 of the first embodiment, a balance can be achieved between a low elastic constant in the prying and torsional directions and a high elastic constant in the direction perpendicular to the axis. Furthermore, since the sliding inner liner 34 is constructed by combining segmented inner liners 62a and 62b, with coarse holes 44 and fine holes 4 respectively formed at the ends, it simplifies the manufacturing of the weave with altered hole coarseness compared to the sliding inner liner 34 of the second embodiment, which requires the coarse holes 44 to be formed between the fine holes 42 and 42.

[0083] exist Figure 5 In this embodiment, a suspension bushing 70 is shown as a sliding bushing according to the structure of the fourth embodiment. The suspension bushing 70 has a sliding inner bushing 72 whose axial length dimension is smaller than that of the inner shaft member 12. The sliding inner bushing 72 is only partially provided in the axial middle portion of the inner shaft member 12. The axial length dimension of the sliding inner bushing 72 is set to be smaller than the axial length dimension of the overlapping surface of the inner shaft member 12 and the main body rubber elastomer 16, and the sliding inner bushing 72 is only provided in the axial central portion of the overlapping surface of the inner shaft member 12 and the main body rubber elastomer 16. Specifically, the sliding inner bushing 72 is configured, for example, to cover the entire outer peripheral surface of the protrusion 18 in the inner shaft member 12 and the inner sidewall surface of the axially inner side of the recess 24, while the inner bottom wall surface of the recess 24 and the surface of the protrusion 22 are not covered by the sliding inner bushing 72.

[0084] The sliding liner 72 is only partially disposed in the middle portion of the axial direction, so that the two axial ends of the main rubber elastomer 16 off-center from the sliding liner 72 directly overlap with the inner shaft member 12. In other words, the overlapping surface of the inner shaft member 12 and the main rubber elastomer 16 extends to the outer side of the axial direction than the sliding liner 72. Specifically, the inner surface of the bottom wall of the recess 24 in the inner shaft member 12 overlaps with the main rubber elastomer 16 in direct contact without passing through the sliding liner 72. In this embodiment, the inner shaft member 12 and the main rubber elastomer 16 are also not bonded on the two outer sides of the axial direction off-center from the sliding liner 72, allowing the inner shaft member 12 and the main rubber elastomer 16 to slide. It should be noted that the inner shaft member 12 and the main rubber elastomer 16 may also be bonded to each other on the two outer sides of the axial direction off-center from the sliding liner 72.

[0085] In this way, the inner shaft member 12 and the main rubber elastomer 16 directly overlap on the outer side of the sliding liner 72, thereby setting a larger sliding resistance between the overlapping surfaces of the inner shaft member 12 and the main rubber elastomer 16. In this embodiment, because the inner shaft member 12 and the main rubber elastomer 16 are not bonded at the two ends of the axial direction and are allowed to slide, the coefficient of friction between the inner shaft member 12 and the main rubber elastomer 16 at the two ends of the axial direction is greater than that at the central part of the axial direction where the sliding liner 72 is disposed.

[0086] According to the sliding bushing suspension bushing 70 configured in accordance with the structure of this embodiment described above, when input is made in the axial vertical direction, the main rubber elastomer 16 is more likely to retract axially outward, and a high elastic constant can be set in the axial vertical direction.

[0087] It should be noted that, as... Figure 6 The suspension bushing 80 of the sliding bushing shown can also have a recessed portion 82 that bends outwards to the outer periphery, located axially outwards from the tapered portion 28 in the outer cylinder member 14. Accordingly, the end face of the outer cylinder member 14 faces the outer periphery, and the inner peripheral surface 84 of the axial end of the outer cylinder member 14 is set as a smooth curved surface without edges. Therefore, it is possible to prevent the edge of the axial end of the outer cylinder member 14 from contacting the main rubber elastomer 16 during vibration input, thus avoiding damage to the main rubber elastomer 16. In addition, by providing the recessed portion 82 with a curved profile at the axial end of the outer cylinder member 14, the deformation rigidity of the outer cylinder member 14 can also be improved.

[0088] The embodiments of the present invention have been described in detail above, but the present invention is not limited to its specific description. For example, the protrusion 18 of the inner shaft member 12 can be provided at the middle of the axial direction of the inner shaft member 12, or it can be biased in any direction relative to the axial center of the inner shaft member 12. The protrusion 18 is preferably located at a position corresponding to the axial center of the inner shaft member 12. Figure 1In the longitudinal section, it has an outer peripheral surface shape that is arc-shaped, but for example, it can also adopt an outer peripheral surface shape that is roughly trapezoidal or polygonal.

[0089] The recess 24 of the inner shaft member 12 is not necessary. Alternatively, the recess 24 may, for example, be open axially outward.

[0090] The inclination angles of the inner and outer circumferential surfaces of the tapered portions 28, 28 of the outer cylinder member 14 can also be different. For example, the tapered portion can be inclined inward with only the inner circumferential surface facing outward along the axial direction, or it can be a thick wall facing outward along the axial direction. In addition, the maximum outer diameter R2 of the protrusion 18 of the inner shaft member 12 can also be smaller than the minimum inner diameter R1 of the tapered portions 28, 28 of the outer cylinder member 14.

[0091] To avoid interference with the outer cylinder member 14 during prying input, a recessed part that opens to the end of the outer cylinder member 14 and extends circumferentially may be provided in the inner shaft member 12 and / or the main body rubber elastomer 16 inner side fixing mounting part 30.

[0092] The main rubber elastomer 16 can also be formed from a self-lubricating rubber material with a low coefficient of friction due to mixing with oil or the like, thereby further improving the sliding properties between the inner shaft member 12 and the main rubber elastomer 16.

[0093] The sliding liner can be a structure divided into multiple parts in the circumferential direction. Furthermore, while the third embodiment illustrates a sliding liner 34 divided into two parts in the axial direction, it is also possible to use sliding liners divided into three or more parts in the axial direction. In this case, for example, the sliding liner can be divided in such a way that the coarse-hole portion 44 of the protrusion 18 mounted on the inner shaft member 12 and the fine-hole portions 42, 42 of the small-diameter cylindrical portions 20, 20 mounted on the inner shaft member 12 are each independently separated. Furthermore, there are no limitations on the weaving or knitting method of the sliding liner; for example, it can be woven in a cylindrical shape having bulges corresponding to the shape of the outer peripheral surface of the protrusion 18.

[0094] The main rubber elastomer can also be configured to be limited to the length of the outer peripheral surface of the protrusion 18 of the inner shaft member 12. In this case, a large-diameter portion and a small-diameter portion are provided in the protrusion 18 of the inner shaft member 12, and the sliding liner is disposed across these large-diameter portions and the small-diameter portion. Thus, the small-diameter portion is not necessarily limited to the portion of the protrusion 18 that deviates axially outward in the inner shaft member 12, but may also include the axial end of the protrusion 18 with a smaller diameter.

[0095] In the above embodiments, an example of applying the present invention to suspension bushings for motor vehicles is shown, but the present invention can also be applied to sliding bushings other than suspension bushings.

[0096] Explanation of reference numerals in the attached figures

[0097] 10: Suspension bushing (sliding bushing, first embodiment);

[0098] 12: Inner shaft components;

[0099] 14: Outer cylinder components;

[0100] 16: Main body rubber elastomer;

[0101] 18: Protruding part (large diameter part);

[0102] 20: Small-diameter cylindrical section (small-diameter section);

[0103] 22: Protrusion;

[0104] 24: concave part;

[0105] 26: Cylindrical section;

[0106] 28: Conical part;

[0107] 30: Inner fixed mounting part;

[0108] 32: Depression;

[0109] 34: Sliding lining;

[0110] 36: Braided holes or woven holes (holes in a braid);

[0111] 38: Incision;

[0112] 42: Fine pores;

[0113] 44: Coarse pore section;

[0114] 50: Sliding liner (second embodiment);

[0115] 52: Woven holes or braided holes (holes in a braid);

[0116] 60: Sliding liner (third embodiment);

[0117] 62: Segmented lining;

[0118] 70: Suspension bushing (fourth embodiment of sliding bushing);

[0119] 72: Sliding lining;

[0120] 80: Suspension bushing (another embodiment of the sliding bushing);

[0121] 82: Retreat;

[0122] 84: Inner circumference.

Claims

1. A sliding bushing (10, 70, 80) having an inner shaft member (12) and an outer cylinder member (14) connected by a main body rubber elastomer (16) and allowing the inner shaft member (12) to slide relative to the main body rubber elastomer (16), wherein, The inner shaft member (12) has a protrusion in the middle of its axial direction, and A woven fabric-like sliding liner (34, 50, 60, 72) is non-adhesive to the inner shaft member (12) and slidably disposed between the inner shaft member (12) and the main rubber elastomer (16). In the sliding liner (34, 50, 60, 72), a portion of the large-diameter portion (18) disposed relative to the protrusion of the inner shaft member (12) is provided with a coarse-hole portion (44) whose woven holes are coarser than the portions of the small-diameter portions (20) disposed on both sides of the axial direction of the large-diameter portion (18) in the sliding liner (34, 50, 60, 72).

2. The sliding bushing (10, 70, 80) according to claim 1, wherein, A cut (38) is formed in the coarse-hole portion (44) of the sliding liner (34, 50, 60, 72).

3. The sliding bushing (10, 70, 80) according to claim 1 or 2, wherein, The sliding lining (34, 50, 60, 72) is loosely woven at the coarse-hole portion (44).

4. The sliding bushing (10) according to claim 1 or 2, wherein, The sliding liner (60) is composed of two segmented liners (62) that are axially joined together on the inner shaft member (12). The ends of the mating sides of the two segmented liners (62) are arranged on the outer periphery of the large diameter portion (18) of the protrusion of the inner shaft member (12) and are configured as the coarse hole portion (44).

5. The sliding bushing (10) according to claim 1 or 2, wherein, The sliding liners (34, 50, 60) are disposed between the inner shaft member (12) and the entire overlapping surface of the main rubber elastomer (16).

6. The sliding bushing (70, 80) according to claim 1 or 2, wherein, The overlapping surface of the inner shaft member (12) and the main rubber elastomer (16) extends to a position axially outer than the sliding liner (72).

7. The sliding bushing (10, 70, 80) according to claim 1 or 2, wherein, The outer cylinder component (14) has two axially oriented outer ends that form small-diameter tapered portions (28). The minimum inner diameter of the tapered portion (28) of the outer cylinder member (14) is smaller than the maximum outer diameter of the protrusion in the inner shaft member (12).

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