Anti-vibration device and method for manufacturing Anti-vibration device

Abstract

To simultaneously establish suppression of generation of a drawing line, reduction of torsional rigidity by high pre-compression, and holding or improvement of axial rigidity by a bent part.SOLUTION: The vibration control device 1 includes an inside member 10 having a cylindrical shape, an outside member 20 surrounding the inside member 10 from the side, and an elastic member 30 interposed between the inside member 10 and the outside member 20 to elastically connect both of them. The anti-vibration device 1 includes a bulging portion 12 bulging radially outward from an outer peripheral surface 11 of the inner member 10, bent portions 21 disposed at both end portions of the outer member 20 in the axial direction (a 20b portion of an outer end portion in the axial direction) and extending radially inward so as to sandwich the elastic member 30 located between the outer member 20 and the bulging portion 12 from both sides in the axial direction, and a first slit 22 cutting the outer member 20 in the axial direction so that the outer member 20 has a C-shape in a cross-sectional view and allowing elastic deformation of the outer member 20 in the circumferential direction so as to open and close an opening of the C-shape.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an anti-vibration device and a method for manufacturing an anti-vibration device. [Background technology]

[0002] For example, Patent Document 1 discloses a vibration-isolating bushing as a vibration-isolating device. Specifically, this vibration-isolating bushing includes an inner shaft member as an inner member, an outer shaft member as an outer member, and an elastic member as an elastic member.

[0003] The inner member has a cylindrical shape with one spherical portion molded into a spherical shape, the outer member has a cylindrical shape facing the spherical portion, and the elastic member connects the inner member and the outer member so as to cover the spherical portion.

[0004] The outer member has bent portions near both end edges thereof that are bent toward the inner member. These bent portions are bent toward the inner member at approximately right angles by high pressure processing, and are pressed against both end portions of the elastic member.

[0005] According to Patent Document 1, when the inner member moves in the axial direction, the bent portion and the spherical portion act as walls, compressing the elastic member sandwiched between them in the axial direction. This compression makes the elastic member less likely to deform in the axial direction. As a result, the axial rigidity (axial spring constant) of the vibration-damping bushing increases.

[0006] Furthermore, the elastic member disclosed in Patent Document 1 is prone to deformation in the prying direction, starting from the spherical portion. As a result, the anti-prying rigidity (spring constant in the prying direction) of the vibration-damping bushing is low. In other words, the anti-prying rigidity of the vibration-damping bushing disclosed in Patent Document 1 has a high ratio of axial rigidity to anti-prying rigidity.

[0007] Meanwhile, Patent Document 2 discloses a damping element as another example of a vibration-damping device. Specifically, this vibration-damping bushing includes an inner tube having an annular raised portion corresponding to the spherical portion, and an outer tube facing the annular raised portion with a rubber annular member sandwiched therebetween.

[0008] According to Patent Document 2, the outer tube according to this document has an inner circumferential surface that has a cross-sectional shape that is curved in a substantially arc shape, instead of the bent portion according to Patent Document 1. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-323080 [Patent Document 2] DE 10227978 Summary of the Invention [Problem to be solved by the invention]

[0010] The inventors of the present application have pursued softer spring characteristics in the torsional direction in vibration isolation devices as vibration isolation bushes as in the above-mentioned Patent Documents 1 and 2.

[0011] To achieve such spring characteristics, it is thought that the shear strain of the elastic member near the part corresponding to the spherical portion can be increased by sufficiently pre-compressing the elastic member in the radial direction (hereinafter referred to as "high pre-compression"). By increasing the shear strain, it becomes possible to reduce the torsional rigidity (spring constant in the torsional direction) of the vibration isolation device.

[0012] Conventionally, in order to realize a high pre-compression of the elastic member, it has been widely known to apply a drawing process to the outer member (outer cylinder) to reduce the diameter of the outer member.

[0013] However, increasing the shear strain of the elastic member reduces not only the torsional rigidity but also the axial rigidity (spring constant in the axial direction). In other words, increasing the pre-compression of the elastic member reduces not only the torsional rigidity but also the axial rigidity.

[0014] Therefore, it has been thought that by using a bent portion as described in Patent Document 1, it is possible to achieve both a reduction in torsional rigidity and the maintenance or improvement of axial rigidity.

[0015] However, when the diameter of the outer member is reduced by conventional drawing, the elastic member pressed by the outer member is distorted in the axial direction, and as a result of being pressed by the axially distorted elastic member, the bent portion may open.

[0016] Therefore, it is conceivable to prepare a thick and heavy outer member as in Patent Document 2. However, in this case, machining of the inner peripheral surface of the outer member is required, which is inconvenient in terms of reducing manufacturing costs.

[0017] Furthermore, when conventional drawing processes are used, there is a possibility that scratches called "drawing lines" will appear on the outer surface of the outer member due to distortion. Such drawing lines not only mar the aesthetic appearance of the vibration isolation device, but also pose the risk of causing unintended problems when assembling the final product.

[0018] The outer member as in Patent Document 2 is also disadvantageous because the amount of deformation during drawing is large in proportion to its thickness, and there is a greater risk of the occurrence of the aforementioned drawing lines compared to a thinner outer member.

[0019] The present disclosure has been made in consideration of these points, and aims to simultaneously suppress the occurrence of narrowing lines, reduce torsional rigidity by increasing pre-compression, and maintain or improve axial rigidity by using bent sections. [Means for solving the problem]

[0020] A first aspect of the present disclosure relates to a vibration-damping device comprising an inner member having an axial or cylindrical shape, an outer member that surrounds the inner member from the side, and an elastic member that is interposed between the inner member and the outer member and elastically connects them together.

[0021] According to the first aspect, the vibration-damping device comprises a bulging portion that bulges radially outward from the outer peripheral surface of the inner member and faces the outer member across the elastic member, a bent portion that is arranged at both ends of the outer member in the axial direction and extends radially inward so as to sandwich the elastic member located between the outer member and the bulging portion from both sides in the axial direction, and a first slit that cuts the outer member in the axial direction so that the outer member has a C-shape in cross section and allows elastic deformation of the outer member in the circumferential direction to open and close the C-shaped opening.

[0022] According to the first aspect, the first slits provided in the outer member open and close the outer member in the circumferential direction by elastic deformation. As a result, for example, even without drawing the outer member after vulcanization integral molding, by preparing an outer member whose diameter has been reduced in advance and configuring it so that the C-shape is closed, high pre-compression of the elastic member can be achieved.

[0023] Furthermore, elastic deformation requires less load and the strain associated with it is smaller than that caused by plastic deformation due to drawing, which reduces the strain on the outer member and suppresses the occurrence of drawing lines.

[0024] Furthermore, by configuring the outer member to open and close in the circumferential direction, the strain generated in the elastic member through the outer member is dispersed in both the axial and circumferential directions. Dispersing the strain in the circumferential direction also changes the strain distribution in the elastic member so that it wraps around the bulge in the circumferential direction. This reduces the torsional rigidity of the vibration-damping device and prevents the opening of the bent portion due to pressure from the elastic member.

[0025] Furthermore, by suppressing the opening of the bent portion, it is possible to simultaneously suppress the occurrence of narrowing lines while reducing torsional rigidity due to high pre-compression and maintaining or improving axial rigidity due to the bent portion.

[0026] Furthermore, by suppressing the opening of the bent portion, the bent portion can be bent more sharply, which is advantageous for further improving the axial rigidity.

[0027] Other possible measures to reduce torsional rigidity include reducing the contact area between the elastic member and the inner member by making the bulge smaller, or reducing the hardness (e.g., rubber hardness) of the elastic member.

[0028] However, all of these other measures are disadvantageous because they result in a decrease in the stiffness in the axial direction (spring constant in the axial direction).

[0029] In contrast, the first aspect can reduce the torsional rigidity while maintaining the rigidity in the axial direction, thereby achieving an improvement in the axial rigidity and a reduction in the torsional rigidity while maintaining the rigidity in the axial direction.

[0030] In other words, the first aspect makes it possible to realize an elastic member that exhibits the desired performance in three respects: torsional rigidity, axial rigidity, and axial rigidity, in a region (hereinafter also referred to as a "local region") that is sandwiched between two bent portions in the axial direction and between the outer member and the bulge portion in the axial direction.

[0031] As described above, the first aspect is particularly useful in that it can suppress the occurrence of constriction lines in the outer member while allowing the elastic member to exhibit the desired performance.

[0032] Furthermore, according to a second aspect of the present disclosure, the vibration-damping device may include a second slit that cuts the elastic member in the axial direction so that the elastic member has a C-shape in cross section and allows elastic deformation of the elastic member in the circumferential direction, and the first and second slits may be arranged so that their angular positions in the circumferential direction coincide when the vibration-damping device is assembled.

[0033] According to the second aspect, by providing the second slits in the elastic member, the strain distribution in the elastic member is distributed in a balanced manner in the axial and circumferential directions, which is advantageous in suppressing opening of the bent portion due to pressure from the elastic member.

[0034] Furthermore, according to a third aspect of the present disclosure, the vibration-damping device may include recesses located on both sides of the bulge in the axial direction, the recesses narrowing the outer peripheral surface of the inner member radially inward, a portion of the elastic member being disposed within the recesses, and the amount of narrowing of the recesses relative to the outer peripheral surface of the inner member being shorter than the radial distance between the bulge and the inner peripheral surface of the outer member.

[0035] According to the third aspect, the outer peripheral surface of the inner member is provided with a recessed portion, and a portion of the elastic member is positioned within the recessed portion. By disposing a portion of the elastic member within the recessed portion, it is possible to provide an adjustment margin for adjusting various properties of the elastic member (particularly, torsional rigidity, transverse rigidity, and axial rigidity).

[0036] Furthermore, by making the amount of diameter reduction of the recessed portion shorter than the distance between the bulge portion and the inner circumferential surface of the outer member, the volume of the elastic member located in the localized region can be made as large as possible in the radial direction, which is advantageous in enabling the elastic member to exhibit the desired performance.

[0037] Furthermore, according to a fourth aspect of the present disclosure, the axial dimension of the portion of the inner surface of the outer member that faces the bulge portion across the elastic member may be longer than the axial dimension of the portion that faces the recessed portion across the elastic member.

[0038] According to the fourth aspect, the volume of the elastic member located in the local region can be made as large as possible in the axial direction, which is advantageous in enabling the elastic member to exhibit desired performance.

[0039] According to a fifth aspect of the present disclosure, a pre-compression ratio of the elastic member in the radial direction when the slit is closed may be set to 16% or more.

[0040] After extensive research, the inventors of the present invention have found that by adopting the bent portion and the first slit as in the first embodiment, a high pre-compression ratio of the elastic member can be achieved. As a result, the pre-compression ratio of the elastic member can reach 16% or more. This is advantageous for reducing torsional rigidity due to the high pre-compression ratio.

[0041] A sixth aspect of the present disclosure relates to a method for manufacturing the vibration-damping device, which may include a step of integrally vulcanizing the inner member, the outer member, and the elastic member, and a step of forming the bent portion before closing the first slit, which is carried out before or after the integrally vulcanizing molding step.

[0042] According to the sixth aspect, instead of conventional drawing, the first slits are closed to prevent the bent portions from being released, thereby preventing the occurrence of drawing lines caused by conventional drawing, and simultaneously achieving a reduction in torsional rigidity due to high pre-compression and maintaining or improving axial rigidity due to the bent portions. [Effects of the Invention]

[0043] As described above, according to the present disclosure, it is possible to simultaneously suppress the occurrence of narrowing lines, reduce torsional rigidity by increasing pre-compression, and maintain or improve axial rigidity by the bent portion. [Brief explanation of the drawings]

[0044] [Figure 1]FIG. 1 is a perspective view illustrating an example of an anti-vibration device. [Figure 2] FIG. 2 is a side view illustrating the configuration of the vibration isolation device. [Figure 3] FIG. 3 is a cross-sectional view illustrating the configuration of the vibration isolation device. [Figure 4] FIG. 4 is a vertical cross-sectional view illustrating the configuration of the vibration isolation device. [Figure 5] FIG. 5 is a partially enlarged view of FIG. [Figure 6] FIG. 6 is a perspective view illustrating an example of the vibration isolation device with the slits closed. [Figure 7A] FIG. 7A is a flowchart illustrating a method for manufacturing an anti-vibration device. [Figure 7B] FIG. 7B is a flowchart illustrating a method for manufacturing an anti-vibration device. [Figure 8] FIG. 8 is a table showing examples and comparative examples of vibration isolation devices. [Figure 9] FIG. 9 is a view corresponding to FIG. 6, showing a comparative example 1 of the vibration isolation device. [Figure 10] FIG. 10 is a view corresponding to FIG. 5 and shows a second comparative example of the vibration isolation device. [Figure 11A] FIG. 11A is a plot showing the magnitude of the torsion spring constant relative to the outer diameter of the bulging portion in each configuration example. [Figure 11B] FIG. 11B is a plot showing the magnitude of the torsional spring constant versus the axial / axial ratio in each configuration example. DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the following description is an example.

[0046] <Configuration of vibration isolation device 1> FIG. 1 is a perspective view illustrating the configuration of an anti-vibration device 1. FIG. 2 is a side view illustrating the configuration of an anti-vibration device 1. FIG. 3 is a horizontal cross-sectional view illustrating the configuration of an anti-vibration device 1, and FIG. 4 is a vertical cross-sectional view illustrating the configuration of an anti-vibration device 1. FIG. 5 is a partially enlarged view of FIG. 4. Note that FIG. 2 is a view seen from the arrow II in FIG. 1, and FIG. 4 shows a horizontal cross-section taken along line IV-IV in FIG. 1.

[0047] As illustrated in Fig. 1 and other figures, the vibration isolation device 1 according to this embodiment is configured as a so-called vibration isolation bushing. The vibration isolation device 1 as a vibration isolation bushing can be used, for example, as a suspension bushing for an automobile. When used as a suspension bushing, the vibration isolation device 1 can attenuate vibrations of the vehicle body when the vehicle is traveling.

[0048] As shown in Figures 1 to 3, the vibration-damping device 1 comprises an inner member 10, an outer member 20, and an elastic member 30. Of these elements, the inner member 10 has an axial or cylindrical shape. The outer member 20 has a cylindrical shape that surrounds the inner member 10 from the side. The elastic member 30 is interposed between the inner member 10 and the outer member 20, and elastically connects them together.

[0049] As shown in FIG. 1 and other figures, the inner member 10 constituting the vibration-damping device 1 has a central axis O extending in a predetermined direction. Hereinafter, the direction extending along the central axis O will be referred to as the "axial direction," and the direction perpendicular to this "axial direction" will be referred to as the "axial-perpendicular direction." The axial-perpendicular direction includes a "radial direction (see dashed line Q in FIG. 3)" extending radially from the central axis O, and a "circumferential direction" circumferentially around the central axis O. For example, in FIG. 4, the left-right direction on the paper surface corresponds to the axial direction, and the up-down direction on the paper surface corresponds to the axial-perpendicular direction.

[0050] Additionally, the direction of rotation around the central axis O is referred to as the "torsion direction," and the direction of rotation around the axis perpendicular direction, such as the chain line Q in Figure 3, is referred to as the "torsion direction."

[0051] The inner member 10 is configured as an "inner cylinder" having a cylindrical shape. The inner member 10 is fastened to a bracket on the vehicle body side by bolts, for example. The inner member 10 is made of metal such as iron or aluminum.

[0052] The inner member 10 has a bulging portion 12 that bulges (projects) radially outward from the outer peripheral surface 11 of the inner member 10. The bulging portion 12 is disposed so as to face the outer member 20 across the elastic member 30. The bulging portion 12 functions as a so-called pillow ball.

[0053] Specifically, the bulging portion 12 bulges out from the axial center portion 10a of the outer peripheral surface 11. The bulging portion 12, which is configured as a pillow ball, has a spherical shape. As shown in Fig. 4, the dimension of the bulging portion 12 in the axial direction is shorter than the dimension of the outer member 20 in the same direction.

[0054] The inner member 10 has two recessed portions 13. The two recessed portions 13 are located on both sides of the bulging portion 12 in the axial direction. Each recessed portion 13 is formed by reducing the diameter of the outer peripheral surface 11 of the inner member 10 radially inward. Each of the two recessed portions 13 forms a groove that extends annularly over the entire circumferential circumference. A portion of the elastic member 30 (the axial outer end portion 30c) is disposed within each recessed portion 13.

[0055] Also, as shown in Figure 5, the amount of diameter reduction of the recessed portion 13 based on the outer peripheral surface 11 of the inner member 10 (see double arrow H1) is shorter than the radial distance between the bulge portion 12 and the inner peripheral surface 23 of the outer member 20 (see double arrow H2).

[0056] Also, as shown in Figure 5, the amount of expansion of the bulge portion 12 based on the bottom surface of the recessed portion 13 (the outer diameter of the bulge portion 12, see double-headed arrow H3) is longer than the radial distance between the bulge portion 12 and the inner surface 23 of the outer member 20 (see double-headed arrow H2).

[0057] The outer member 20 is configured as an "outer cylinder" having a cylindrical shape extending along the central axis O. The outer member 20 is, for example, press-fitted and fixed to a cylindrical portion (not shown) of a suspension link. The outer member 20 is made of metal (iron, aluminum, etc.).

[0058] The outer member 20 is disposed to face the bulge 12 with the elastic member 30 sandwiched therebetween. Specifically, the axial center portion 20a of the outer member 20 corresponds to the bulge 12 (axial center portion 10a), as shown in Fig. 3. The axial outer end portion 10b of the inner member 10 is positioned axially outward of the axial outer end portion 20b of the outer member 20. The bulge 12 is the starting point of displacement of the vibration-damping device 1 in the prying direction.

[0059] As shown in FIG. 5, the axial dimension L1 of the portion of inner circumferential surface 23 of outer member 20 facing bulging portion 12 is longer than the axial dimension L2 of the portion facing recessed portion 13.

[0060] The outer member 20 has bent portions 21 disposed at both axial ends (axial outer end portions 20b) of the outer member 20. These bent portions 21 extend radially inward so as to sandwich the elastic member 30, which is located between the outer member 20 and the bulging portion 12, from both axial sides.

[0061] More specifically, each bent portion 21 is formed by bending the axially outer end portion 20b of the outer member 20 radially inward. The outer member 20 and each bent portion 21 are configured using a thin metal plate member, without using a thick member for the outer member 20.

[0062] More specifically, each bent portion 21 extends radially inward and perpendicular to the central axis O. In other words, as shown in FIG. 4, an imaginary line T extending radially inward from a bent portion 21 intersects with the central axis O perpendicularly.

[0063] As shown in FIG. 5, the inner diameter side end 21a of each bent portion 21 is disposed with a gap in the radial direction from both the outer circumferential surface 11 of the inner member 10 and the elastic member 30.

[0064] The outer member 20 also has a first slit 22 shown in Figures 1 to 3. The first slit 22 is formed to cut through the outer member 20 in the axial direction so that the outer member 20 has a C-shape in cross section.

[0065] Furthermore, as can be seen from a comparison between Figures 1 and 6, the first slit 22 is configured to allow elastic deformation of the outer member 20 in the circumferential direction so as to open and close the C-shaped opening (C-shaped with the upward facing surface of the paper) illustrated in Figure 3.

[0066] 1 corresponds to a state after the completion of the drawing process described below, in which the vibration-damping device 1 is about to be press-fitted into a mating part (assembly destination) of an automobile, etc. Even at this stage, the vibration-damping device 1 still maintains its C-shape without closing the first slit 22 by welding or the like.

[0067] The elastic member 30 is configured as an "elastic body" that exerts restoring force in both the axial direction and the axial direction (the direction perpendicular to the central axis O). The elastic member 30 is configured from one or a blend of two or more of natural rubber and (diene-based) synthetic rubber. The elastic member 30 has a tubular shape (particularly a cylindrical shape).

[0068] The elastic member 30 is integrally vulcanization molded together with the inner member 10 and the outer member 20. As shown in Figures 4 and 5, a spherical recess 31 recessed radially outward is provided in an axial center portion 30a of the inner peripheral surface of the elastic member 30 so as to correspond to the bulging portion 12 of the inner member 10. The bulging portion 12 fits into the recess 31. A protrusion 32 protrudes axially outward from this recess 31. The protrusion 32 is in close contact with the inner peripheral surface 23 of the outer member 20.

[0069] Further, on both sides in the axial direction of the elastic member 30, there are provided an inner peripheral groove portion 30b recessed inward in the axial direction, an outer end portion 30c in the axial direction, and a remaining portion 30d.

[0070] The two inner circumferential groove portions 30b are located axially inward of the axial outer end portion 10b of the inner member 10 and the axial outer end portion 20b of the outer member 20. The groove bottoms of the inner circumferential groove portions 30b are rounded in an arc shape in the longitudinal cross sections of Figures 4 and 5. The two inner circumferential groove portions 30b provided on both sides of the elastic member 30 each form a groove that extends annularly over the entire circumferential direction.

[0071] The two axially outer end portions 30c of the elastic member 30 are each disposed within the recessed portion 13 of the inner member 10. Further axially outward from each of the axially outer end portions 30c, a remaining portion 30d is disposed which is attached to the inner member 10 axially outward from the recessed portion 13.

[0072] The elastic member 30 also has a second slit 33 shown in Figures 1 to 3. The second slit 33 is formed to cut the elastic member 30 in the axial direction so that the elastic member 30 has a C-shape in cross section.

[0073] Furthermore, as can be seen from a comparison between Figures 1 and 6, the second slit 33 is configured to allow elastic deformation of the elastic member 30 in the circumferential direction so as to open and close the C-shaped opening (C-shaped opening facing upward in the paper) illustrated in Figure 3.

[0074] 1 corresponds to a state in which the vibration-damping device 1 is about to be press-fitted into a mating part (assembly destination) of an automobile or the like after completion of the vulcanization integral molding and the formation of the bent portion 21, which will be described later. Even in this state, the vibration-damping device 1 maintains its C-shape without closing the second slit 33 by welding or the like.

[0075] The C-shape of the vibration isolator 1 is closed when it is press-fitted into the mating part. Once press-fitting into the mating part is complete, the first and second slits 22, 33 of the vibration isolator 1 are elastically deformed and become closed as shown in FIG.

[0076] Furthermore, the pre-compression ratio of the elastic member 30 in the radial direction when the first slits 22 are closed is preferably set to 16% or more. The pre-compression ratio here can be expressed as "pre-compression ratio = 1 - (T2 / T1)," where T1 is the thickness (radial thickness) of the elastic member 30 when the first slits 22 are open, and T2 is the thickness (radial thickness) of the elastic member 30 when the first slits 22 are closed.

[0077] 2 and 3, the first and second slits 22, 33 are arranged so that their angular positions in the circumferential direction coincide with each other when the vibration-damping device 1 is assembled. In the illustrated example, the first and second slits 22, 33 are arranged at the 12 o'clock position on the paper as viewed from the central axis O.

[0078] <Method of manufacturing the vibration isolation device 1> 7A and 7B are flow charts illustrating a method for manufacturing the vibration isolation device 1. Fig. 7A corresponds to the manufacturing method of Example 1, which will be described later, and Fig. 7B corresponds to the manufacturing method of Example 2, which will also be described later.

[0079] As shown in Figures 7A and 7B, the manufacturing method of the vibration-damping device 1 includes a step of vulcanizing and integrally molding the inner member 10, the outer member 20, and the elastic member 30, and a step of forming the bent portion 21 before closing the C-shape (first slit 22), which is carried out before or after the vulcanization and integrally molding step.

[0080] In the example of Fig. 7A, a step (step S11) of forming bent portions 21 in outer member 20 is carried out prior to the step (step S12) of vulcanization and integral molding. Although first slits 22 are provided in outer member 20 at the stage of step S11, a step of closing these slits is carried out in step S13 after vulcanization and integral molding. First slits 22 may be closed when press-fitting into a mating component, as described above.

[0081] In the example of Fig. 7B, the step of vulcanization integral molding (step S21) is followed by the step of forming bent portions 21 in outer member 20 (step S22). At the stage of step S22, first slits 22 are provided in outer member 20, but the step of closing these slits is performed in step S23 after forming bent portions 21. First slits 22 may be closed when press-fitting into a mating component, as described above.

[0082] <Example of vibration isolation device 1> Fig. 8 is a table showing examples and comparative examples of the vibration isolation device 1. Fig. 9 is a diagram corresponding to Fig. 6 showing comparative example 1 of the vibration isolation device 1, and Fig. 10 is a diagram corresponding to Fig. 5 showing comparative example 2 of the vibration isolation device 1.

[0083] The table in Fig. 8 shows two examples (Example 1 and Example 2) to which the configurations described with reference to Fig. 1 to Fig. 6 are applied, and five comparative examples (Comparative Examples 1 to 5) to which other configurations are applied. Examples 1 and 2 show cases manufactured by the manufacturing methods shown in Fig. 7A and Fig. 7B, respectively.

[0084] These seven configuration examples have in common that they are vibration-damping devices configured as pillow ball type vibration-damping bushings with bulges 12, and that the inner member, outer member, and elastic member are vulcanized and molded as a single unit.

[0085] "Various characteristic parts" in the table of Fig. 8 are items showing the shape and manufacturing method of each of the seven configuration examples. Specifically, "C-shape" in the table of Fig. 8 is an item showing the presence or absence of the first slit 22 and the second slit 33 that form the C-shape. "Presence" of "C-shape" also indicates that drawing is not performed.

[0086] Furthermore, the "curved object" in the table is an item that indicates whether the configuration is such that the "end" of the thin plate-shaped outer member 20 is curved to form the bent portion 21, as shown in Figures 1 to 6, or whether the configuration is such that the "inner circumference" of the thick outer member 20 is provided with a curved shape by machining, as in Comparative Example 1 described later.

[0087] In addition, the "curving timing" in the table is an item that indicates whether the formation of the bent portion 21 or the machining of the inner surface is performed "before" the vulcanization molding, or whether the formation of the bent portion 21 or the machining of the inner surface is performed "after" the vulcanization molding.

[0088] Example 1 1 to 6, the vibration-damping device 1 according to the first embodiment includes a first slit 22 and a second slit 33 that form a C-shape, and bent portions 21 located at both axial ends of the outer member 20. In other words, in this first embodiment, both ends of the outer member 20 are subject to bending.

[0089] Furthermore, the vibration-damping device 1 is configured such that, before the inner member 10, the outer member 20, and the elastic member 30 are integrally vulcanized, the outer member 20 is prepared with the first and second slits 22, 33 and the bent portion 21 formed in advance.

[0090] Example 2 As illustrated in Figures 1 to 6 and 7B, the vibration-damping device 1 of Example 2 has a first slit 22 and a second slit 33 that form a C-shape, and bent portions 21 located at both axial ends of the outer member 20.

[0091] Furthermore, in the vibration-damping device 1, the first and second slits 22, 33 are formed in advance at a stage before the inner member 10, the outer member 20, and the elastic member 30 are integrally vulcanized and molded, and the outer member 20 is prepared without the bent portion 21. The bent portion 21 in Example 2 is formed by bending (crimping) both axial end portions of the outer member 20 after the integral vulcanization and molding.

[0092] (Comparative Example 1) The vibration-damping device 101 of Comparative Example 1 has bent portions 121 located at both axial ends of the outer member 120, but unlike the configurations illustrated in Figures 1 to 6, etc., it does not have a first slit 22 and a second slit 33 that form a C-shape (see Figure 9).

[0093] Furthermore, in the vibration-damping device 101 according to Comparative Example 1, the outer member 120 is prepared without the bent portions 121 formed therein at a stage before the inner member 110, the outer member 120, and the elastic member 130 are integrally vulcanized and molded. The bent portions 121 in Comparative Example 1 are formed by bending (crimping) both axial end portions of the outer member 120 after the integral vulcanization and molding, as in Example 1.

[0094] Furthermore, the outer member 120 according to Comparative Example 1 is subjected to drawing after the bent portions 124 are formed.

[0095] (Comparative Example 2) The vibration-damping device 201 according to Comparative Example 2 does not have the bent portion 21 as in Examples 1 and 2, and the inner circumferential surface of the thick outer member 220 is recessed to have a concave cross section (see FIG. 10). That is, in Comparative Example 2, the inner circumferential surface of the outer member 220 is the object to be bent (the object to be curved).

[0096] Moreover, the vibration isolation device 201 according to Comparative Example 2 differs from the configuration illustrated in FIGS. 1 to 6 and does not include the first slit 22 and the second slit 33 forming a C-shape.

[0097] In addition, Figure 8 provides a case called "Comparative Example 2 (Reproduction)" in which the inventors of the present application actually reproduced the product and compared various measurement results, and a case called "Comparative Example 2 (Specifications)" in which the catalog specifications of Comparative Example 2 were compared.

[0098] (Comparative Examples 3 to 5) For the remaining Comparative Examples 3, 4, and 5, only various published values ​​and / or parameters that can be calculated based on published values ​​are shown.

[0099] These comparative examples 3 to 5 are common to comparative examples 1 and 2 in that none of them has the first slit 22 and the second slit 33 that form the C-shape (see FIG. 8).

[0100] (Comparative results of each example) The "static spring characteristics," "rubber characteristics (squeezing characteristics)," and "structural characteristics" in the table of Fig. 8 represent numerical data that indicate various performances of each of the seven comparative examples. Note that for Examples 1 and 2, the numerical data corresponds to the state in which the C-shape is closed by press-fitting into a mating part, etc.

[0101] Specifically, "X (axial)" indicates the spring constant in the axial direction. "Y (axial)" indicates the spring constant in the axial direction. "X / Y (axial / axial ratio)" indicates the ratio of the spring constant in the axial direction to the spring constant in the axial direction. "θ (torsion)" indicates the torsional spring constant (spring constant in the torsion direction). The spring constant in each direction has a positive correlation with the stiffness of the elastic member 30 in the same direction.

[0102] Furthermore, "rubber hardness (Hs)" indicates the spring hardness (Hardness Spring) of the elastic member 30 as defined by the Japanese Industrial Standards (JIS). "Pre-compression rate (%)" indicates the pre-compression rate (%) of the elastic member 30 in the radial direction as defined above.

[0103] Furthermore, "opening of both ends (spring back)" refers to whether or not both ends of the outer member 20 are released (for example, whether or not the bent portion 21 is released) after drawing or after closing the C-shape. "Presence or absence of scratches" refers to whether or not there are scratches on the surface of the outer member 20 after drawing or after closing the C-shape.

[0104] Fig. 11A is a plot showing the magnitude of the torsional spring constant (spring constant in the torsional direction) versus the outer diameter of the bulging portion 12 in each configuration example. Fig. 11B is a plot showing the magnitude of the torsional spring constant versus the axial straightness / axial ratio in each configuration example.

[0105] 11A and 11B correspond to Examples 1 and 2, respectively. Plots C1 to C5 correspond to Comparative Examples 1 to 5, respectively. Plot C2, which corresponds to Comparative Example 2, is a plot showing a reproduced product.

[0106] 11A, the larger the outer diameter of the bulging portion 12 (see the double-headed arrow H3 in FIG. 5), the larger the torsional spring constant. This is thought to be because the torsional spring constant tends to increase as the contact area between the bulging portion 12 and the elastic member 30 increases.

[0107] In order to reduce the torsional spring constant, it is possible to apply a drawing process to the vibration-damping device after vulcanization and integral molding, as in Comparative Examples 1 and 2, thereby increasing the radial pre-compression of the elastic member.

[0108] In this case, in order to maintain or improve the axial spring constant and reduce the axial straightness / axial ratio shown on the horizontal axis of FIG. 11B, it is conceivable to provide a bent portion 121 as shown in FIG. 9 or to machine the inner peripheral surface of the outer member 220 as shown in FIG. 10.

[0109] However, these measures are disadvantageous because they may cause drawing lines Lx on the surface of the outer member 120 or may cause the bent portion 121 to be released due to spring back, as shown in the table of FIG. 8 and in FIG.

[0110] In contrast, Examples 1 and 2 do not cause the release of the bent portion 21 without causing the draw mark Lx. Although Example 2 causes scratches on the outer member 20 during caulking, it only causes a sense of disharmony in the design and is not of the type that causes inconvenience during press-fitting into the mating part, such as the so-called draw mark Lx.

[0111] Also, since there is no risk of draw marks Lx in Examples 1 and 2, the pre-compression ratio can be increased more than before, and the torsional spring constant can be generally decreased compared with Comparative Examples 1 to 5. The pre-compression ratios of Examples 1 and 2 are 16%. Moreover, since the release of the bent portion 21 is suppressed in Examples 1 and 2, the bent portion 21 can be bent more steeply accordingly.

[0112] Therefore, while maintaining the outer diameter of the bulging portion 12 at about the same level as in Comparative Examples 1 and 2 (that is, while maintaining the axial straight direction spring constant), the axial spring constant can be increased, and as shown in FIG. 11B, the axial straight / axial ratio can be made lower than in various comparative examples.

[0113] <The significance of the C shape> As described above, according to the above embodiment, the first slit 22 provided in the outer member 20 opens and closes the outer member 20 in the circumferential direction by elastic deformation. As described using FIGS. 7A and 7B, for example, even if the outer member 20 after vulcanization integral molding is not subjected to drawing, if the outer member 20 having been pre-reduced in diameter is prepared and configured to close its C shape, high pre-compression of the elastic member 30 can be realized.

[0114] Also, elastic deformation can be caused by a smaller load and the strain associated with the deformation is also small compared with plastic deformation caused by drawing. Therefore, the strain generated in the outer member 20 can be relaxed and the generation of draw marks Lx can be suppressed.

[0115] Furthermore, by configuring the outer member 20 to open and close in the circumferential direction, the strain generated in the elastic member 30 via the outer member 20 is dispersed in both the axial and circumferential directions. By dispersing the strain in the circumferential direction as well, the strain distribution in the elastic member 30 changes so that it wraps around the bulging portion 12 in the circumferential direction. This reduces the torsional rigidity of the vibration-damping device 1 and makes it possible to suppress the opening of the bent portion 21 caused by pressure from the elastic member 30.

[0116] Furthermore, by suppressing the opening of the bent portion 21, it is possible to simultaneously suppress the occurrence of narrowing lines Lx while reducing the torsional rigidity due to high pre-compression and maintaining or improving the axial rigidity by the bent portion 21.

[0117] Furthermore, by suppressing the opening of the bent portion 21, the bent portion 21 can be bent more sharply, as shown by the imaginary line T in Fig. 4. This is advantageous for further improving the axial rigidity.

[0118] Other possible measures to reduce the torsional rigidity include reducing the contact area between the elastic member 30 and the inner member 10 by making the bulge portion 12 smaller, or reducing the hardness (e.g., rubber hardness) of the elastic member 30.

[0119] However, all of these other measures are disadvantageous because they result in a decrease in the stiffness in the axial direction (spring constant in the axial direction).

[0120] In contrast to this, in the above-described embodiment, the torsional rigidity can be improved while maintaining the rigidity in the axial direction, which makes it possible to improve the axial rigidity and reduce the torsional rigidity while maintaining the rigidity in the axial direction.

[0121] That is, in the above embodiment, as indicated by the symbol "Sl" in FIG. 5, an elastic member 30 can be realized in a region (hereinafter also referred to as a "local region") that is sandwiched between two bent portions 21 in the axial direction and between the outer member 20 and the bulging portion 12 in the direction perpendicular to the axis, such that the elastic member 30 exhibits the desired performance in three respects: torsional rigidity, rigidity in the direction perpendicular to the axis, and rigidity in the axial direction.

[0122] As described above, the embodiment is particularly useful in that it is possible to suppress the occurrence of constricting streaks Lx in the outer member 20 while allowing the elastic member 30 to exhibit the desired performance.

[0123] 2 and 3, by providing the second slits 33 in the elastic member 30, the strain distribution in the elastic member 30 is dispersed in a balanced manner in the axial and circumferential directions. This is advantageous in suppressing the opening of the bent portion 21 due to the pressure from the elastic member 30.

[0124] 4 and 5, the outer peripheral surface 11 of the inner member 10 is provided with a recessed portion 13, and a part of the elastic member 30 is positioned within the recessed portion 13. By disposing a part of the elastic member 30 in the recessed portion 13, it is possible to provide an adjustment margin for adjusting various performances of the elastic member 30 (particularly, torsional rigidity, rigidity in the direction perpendicular to the axis, and rigidity in the axial direction).

[0125] 5, the amount of diameter reduction H1 of the recessed portion 13 is set to be shorter than the distance H2 between the bulging portion and the inner circumferential surface of the outer member 20. This makes it possible to maximize the volume of the elastic member 30 located in the local region S1 described above in the radial direction, which is advantageous in enabling the elastic member 30 to exhibit the desired performance.

[0126] 5, the axial dimension L1 of the inner circumferential surface 23 of the outer member 20 at a portion facing the bulge 12 is set to be longer than the axial dimension L2 of the portion facing the recess 13. This allows the volume of the elastic member 30 located in the local region S1 to be as large as possible in the axial direction, which is advantageous in enabling the elastic member 30 to exhibit the desired performance.

[0127] Furthermore, as shown in Fig. 8, the inventors of the present application conducted extensive research and found that by employing the bent portions 21 and the first slits 22 as described above, a high pre-compression of the elastic member 30 was achieved. As a result, it became possible to achieve a pre-compression ratio of 16% or more for the elastic member 30. This is advantageous for reducing torsional rigidity due to the high pre-compression.

[0128] 7A and 7B, instead of the conventional drawing process, the first slits 22 are configured to be closed, thereby suppressing the release of the bent portions 21. This makes it possible to simultaneously achieve a reduction in torsional rigidity due to high pre-compression and maintenance or improvement of axial rigidity by the bent portions 21, while suppressing the generation of drawing lines Lx caused by the conventional drawing process.

[0129] Furthermore, the vibration isolation device 1 according to this embodiment can contribute to achieving Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization, foster innovation and infrastructural resilience," among the Sustainable Development Goals (SDGs), which are international goals aimed at achieving a sustainable and better world by 2030 as set out in the 2030 Agenda for Sustainable Development, which was unanimously adopted by member states at the United Nations Summit in September 2015.

[0130] <Other embodiments> In the above embodiment, the inner member 10, the outer member 20, and the elastic member 30 are integrally molded by vulcanization, but this integral molding is not essential. After the inner member 10 and the elastic member 30 are integrally molded, the molded body may be inserted into the outer member 20 alone.

[0131] The bulging portion 12 serving as a pillow ball may be made of resin or the like instead of metal. Also, the entire inner member 10 and the entire outer member 20 may be made of a material other than metal (e.g., resin or the like). The entire elastic member 30 may be made of a material other than synthetic rubber (e.g., urethane foam or the like).

[0132] Furthermore, of the first slit 22 and the second slit 33, the second slit 33 is not essential. [Explanation of symbols]

[0133] 1. Vibration isolation device 10 Inner member 11 Outer surface 12 Bulge 13 Depression 20 Outer member 21 Bend section 22 First slit 23 Inner surface 30 Elastic member 33 Second slit H1 Diameter reduction amount H2 interval L1 dimension L2 dimension Sl Local area

Claims

1. A vibration-damping device comprising an inner member having an axial or cylindrical shape, an outer member surrounding the inner member from the sides, and an elastic member interposed between the inner member and the outer member to elastically connect them, a bulging portion that bulges outward in the radial direction from the outer peripheral surface of the inner member and faces the outer member across the elastic member; bent portions disposed at both ends of the outer member in the axial direction and extending radially inward so as to sandwich the elastic member located between the outer member and the bulging portion from both sides in the axial direction; a first slit that cuts the outer member in the axial direction so that the outer member has a C-shape in cross section and allows elastic deformation of the outer member in the circumferential direction so as to open and close the C-shaped opening. A vibration isolation device characterized by:

2. 2. The vibration isolation device according to claim 1, a second slit that cuts the elastic member in the axial direction so that the elastic member has a C-shape in cross section and allows elastic deformation of the elastic member in the circumferential direction; The first and second slits are arranged so that their angular positions in the circumferential direction coincide with each other when the vibration-damping device is in an assembled state. A vibration isolation device characterized by:

3. 2. The vibration isolation device according to claim 1, a recessed portion located on both sides of the bulging portion in the axial direction, the recessed portion having a diameter reduced inward on an outer circumferential surface of the inner member; a portion of the elastic member is disposed within the recess; The amount of reduction in diameter of the recessed portion with respect to the outer peripheral surface of the inner member as a reference is shorter than the distance in the radial direction between the bulging portion and the inner peripheral surface of the outer member. A vibration isolation device characterized by:

4. 4. The vibration isolation device according to claim 3, The axial dimension of a portion of the inner circumferential surface of the outer member that faces the bulging portion across the elastic member is longer than the axial dimension of a portion that faces the recessed portion across the elastic member. A vibration isolation device characterized by:

5. 2. The vibration isolation device according to claim 1, The pre-compression ratio of the elastic member in the radial direction when the first slit is closed is set to 16% or more. A vibration isolation device characterized by:

6. 6. The method for manufacturing an anti-vibration device according to claim 1, vulcanization-molding the inner member, the outer member, and the elastic member integrally; and a step of forming the bent portion before closing the first slit, the step being carried out before or after the step of vulcanization integral molding. A method for manufacturing an anti-vibration device, comprising:

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