Vibration control device and manufacturing method therefor

Abstract

To provide a vibration control device capable of preventing burrs from occurring on an end surface of a cylinder member in an axial direction during molding of a vibration control substrate that is vulcanized and bonded to an outer peripheral surface of the cylinder member, and a manufacturing method therefor.SOLUTION: At a corner part 11d of a cylinder member 11, or on the corner part 11d side with respect to a radial center of an end surface 11a of the cylinder member 11, a continuous annular indentation 15 is formed around the entire circumference. When a vibration control substrate 13 to be vulcanized and bonded to an outer peripheral surface 11b of the cylinder member 11 is molded using a mold 30, a projection 38 is pressed to the extent that the indentation 15 is formed, thereby sealing a gap between the mold 30 and the cylinder member 11, so that it is possible to prevent burrs from occurring on the end surface 11a of the cylinder member 11.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a vibration isolation device and a method for manufacturing the same, and more particularly to a vibration isolation device and a method for manufacturing the same that can make it difficult to generate burrs on the axial end faces of a cylindrical member when forming a vibration isolation base vulcanized and adhered to the outer peripheral surface of the cylindrical member.

Background Art

[0002] Conventionally, a vibration isolation device in which a vibration isolation base made of an elastic body is vulcanized and adhered to the outer peripheral surface of a cylindrical member and the inner peripheral surface of a cylindrical outer cylinder, and these are connected, is known (Patent Document 1). Also, a vibration isolation device is known in which the outer cylinder is omitted and the vibration isolation device includes a cylindrical member and a vibration isolation base. These vibration isolation devices are fastened to a mating member by a fastening member such as a bolt passing through the inner peripheral surface side of the cylindrical member. At this time, the axial end face of the cylindrical member becomes a fastening surface that is in close contact with the mating member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional technology, when injecting a molding material of an elastic body into the cavity of a mold holding a cylindrical member to vulcanize and mold a vibration isolation base, even if the end face of the cylindrical member is pressed against the contact surface of the mold, there is a risk that the molding material may penetrate into the gaps due to minute irregularities on each surface. If the molding material is vulcanized and molded as it is, burrs of the elastic body will remain on the end face of the cylindrical member. In order to ensure the adhesion with the mating member during fastening, a process for removing the burrs is required. There are problems such as the process of removing burrs taking a long time or the process becoming complicated when there are many burrs.

[0005] The present invention has been made to solve the above-described problems, and an object thereof is to provide a vibration isolation device and a method for manufacturing the same that can make it difficult to generate burrs on the axial end faces of a cylindrical member during the molding of a vibration isolation base vulcanized and adhered to the outer peripheral surface of the cylindrical member.

Means for Solving the Problems

[0006] To achieve this object, the vibration isolation device of the present invention includes a cylindrical member having an axial end face and an outer peripheral surface connected via a corner portion, and a vibration isolation base made of an elastic body vulcanized and adhered to the outer peripheral surface of the cylindrical member. An annular indentation that is continuous over the entire circumference is formed at the corner portion or on the corner portion side rather than at the radial center of the end face.

[0007] The method for manufacturing the vibration isolation device of the present invention is a method for manufacturing a vibration isolation device including a cylindrical member having an axial end face and an outer peripheral surface connected via a corner portion, and a vibration isolation base made of an elastic body vulcanized and adhered to the outer peripheral surface of the cylindrical member. The method includes a holding step of sandwiching and holding the cylindrical member with molds from both axial sides, and a molding step of injecting a molding material of an elastic body into a cavity of the mold in which the cylindrical member is held in the holding step to vulcanize and mold the vibration isolation base. The mold includes an annular axially facing surface that faces the end face of the cylindrical member in the axial direction in the holding step, and an annular protrusion that protrudes from the axially facing surface toward the cylindrical member and is continuous over the entire circumference in the circumferential direction of the axially facing surface. In the holding step, an annular indentation is formed by pressing the protrusion against the corner portion or on the corner portion side rather than at the radial center of the end face.

Effects of the Invention

[0008] According to the vibration isolation device described in claim 1, an annular indentation that is continuous over the entire circumference is formed at the corner of the cylindrical member or on the corner side rather than the radial center of the end face of the cylindrical member. From this, when molding the vibration isolation base vulcanized and adhered to the outer peripheral surface of the cylindrical member, it can be seen that the indentation was formed by plastic deformation when the protrusion of the mold was pressed against the cylindrical member. Due to the pressing of the protrusion to such an extent that this indentation is formed, the space between the mold and the cylindrical member is sealed, so that it is possible to suppress the molding material of the elastic body from entering from the outer peripheral surface side of the cylindrical member toward the end face side. As a result, it is possible to make it difficult for burrs formed by the solidification of the infiltrated molding material to occur on the end face in the axial direction of the cylindrical member.

[0009] According to the vibration isolation device described in claim 2, in addition to the effects exhibited by the vibration isolation device described in claim 1, the following effects are exhibited. Since the indentation is formed at the corner of the cylindrical member, when molding the vibration isolation base, it is possible to further suppress the molding material of the elastic body from entering from the outer peripheral surface side of the cylindrical member over the corner and toward the end face side. As a result, it is possible to make it more difficult for burrs to occur on the end face in the axial direction of the cylindrical member.

[0010] According to the vibration isolation device described in claim 3, in addition to the effects exhibited by the vibration isolation device described in claim 2, the following effects are exhibited. Since the indentation inclines toward the axial center side as it goes toward the outer side in the radial direction, it can be seen that when molding the vibration isolation base, the indentation was formed by being pressed against the inclined surface of the annular protrusion that is similarly inclined. Thereby, when molding the vibration isolation base, the individual differences in the axial length of the cylindrical member can be absorbed by the inclined surface, and it is possible to suppress the sealing performance from decreasing according to the individual differences when forming the indentation.

[0011] According to the vibration isolation device described in claim 4, in addition to the effects exhibited by the vibration isolation device described in claim 3, the following effects are exhibited. The indentation is provided on a part of the outer peripheral surface side of the corner of the cylindrical member. Thereby, the swelling around when forming the indentation can be absorbed by a part of the end face side of the corner where the indentation is not provided, and it is possible to make it difficult for the end face to swell partially. As a result, when the end face of the cylindrical member is brought into close contact with and fastened to the mating member, the fastening performance can be ensured by ensuring the flatness of the end face.

[0012] According to the vibration isolation device described in claim 5, in addition to the effects achieved by the vibration isolation device described in claim 3, the following effects are achieved. Since the indentation is provided on a part of the end face side of the corner of the cylindrical member, the inclination angle of the annular protrusion for forming the indentation with respect to the end face of the cylindrical member becomes smaller. Therefore, when forming the indentation, it is easier to avoid a state where the cylindrical member is press-fitted into the inclined surface of the annular protrusion. As a result, it is easier to demold the cylindrical member from the mold, and it is possible to suppress the reduction in the diameter of the cylindrical member due to press-fitting.

[0013] According to the method for manufacturing the vibration isolation device described in claim 6, in the holding step of sandwiching and holding the cylindrical member with molds from both axial sides, the annular axially facing surfaces of the molds face the end face of the cylindrical member in the axial direction. By pressing the annular protrusions protruding from this axially facing surface against the corner of the cylindrical member or on the corner side rather than the radially central part of the end face of the cylindrical member, the cylindrical member is plastically deformed to form an annular indentation. In the molding step performed in this state, a molding material of an elastic body is injected into the cavity of the mold, and the vibration isolation base is vulcanized and molded. Since the space between the mold and the cylindrical member is sealed by the protrusions forming the indentation, it is possible to suppress the molding material of the elastic body from infiltrating from the outer peripheral surface side to the end face side of the cylindrical member. As a result, it is possible to make it difficult for burrs formed by the solidification of the infiltrated molding material to occur on the axial end face of the cylindrical member.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0015] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of the vibration isolator 10 in the first embodiment. FIG. 1 shows a cross-section cut along a plane including the axis C of the vibration isolator 10. Hereinafter, the axial direction of the axis C will be simply referred to as the axial direction, the direction perpendicular to the axis C will be simply referred to as the radial direction, and the direction around the axis C will be simply referred to as the circumferential direction for description.

[0016] The vibration isolator 10 is a vibration isolation bush for elastically coupling a vibration source side such as an arm used in an automobile suspension mechanism and a mating member 21 on the vibration receiving side such as a vehicle body. The vibration isolator 10 includes a cylindrical cylindrical member 11, a cylindrical outer cylinder 12 surrounding the outer peripheral side of the cylindrical member 11, and a vibration isolation base 13 connecting them.

[0017] Note that each part of the vibration isolator 10 is basically formed axially symmetrically with respect to the center in the axial direction. Therefore, the description will be made for one end side in the axial direction, and the description of the other end side in the axial direction will be omitted. In addition, each part of the vibration isolator 10 is basically formed axially symmetrically with respect to the axis C.

[0018] The cylindrical member 11 is a cylindrical member centered on the axis C and is made of a rigid material such as a steel material or an aluminum alloy. The cylindrical member 11 includes an end face 11a in the axial direction, an outer peripheral surface 11b, and an inner peripheral surface 11c. The end face 11a is formed by a plane perpendicular to the axis C. The outer peripheral surface 11b and the inner peripheral surface 11c are formed by cylindrical surfaces centered on the axis C.

[0019] The cylindrical member 11 is axially sandwiched between a pair of plate-shaped mating members 21. By inserting a bolt 22 into a through-hole 21a formed through the mating member 21 and the inner peripheral surface 11c side of the cylindrical member 11 and fastening a nut 23 to the bolt 22, the cylindrical member 11 is fastened to the pair of mating members 21. That is, the end face 11a of the cylindrical member 11 is a fastening surface that is in close contact with the mating member 21.

[0020] The outer cylinder 12 is a cylindrical member centered on the axis C and is composed of a rigid material such as a steel material or an aluminum alloy. The outer cylinder 12 is fixed to the vibration source side by press-fitting the outer cylinder 12 into a hole provided on the vibration source side such as an arm.

[0021] The vibration isolation base 13 is a cylindrical member composed of an elastic body such as rubber or a thermoplastic elastomer. The inner peripheral surface of the vibration isolation base 13 is vulcanized and adhered to the outer peripheral surface 11b of the cylindrical member 11, and the outer peripheral surface of the vibration isolation base 13 is vulcanized and adhered to the inner peripheral surface of the outer cylinder 12. Thereby, the vibration isolation base 13 connects the cylindrical member 11 and the outer cylinder 12 over the entire circumference.

[0022] The vibration isolation base 13 includes a main body portion that connects the cylindrical member 11 and the outer cylinder 12 in the radial direction, thin film-like inner membrane portions 14 that extend axially on both sides along the outer peripheral surface 11b of the cylindrical member 11 from the main body portion, and thin film-like outer membrane portions that extend axially on both sides along the inner peripheral surface of the outer cylinder 12 from the main body portion.

[0023] The end face 11a and the outer peripheral surface 11b of the cylindrical member 11 are continuous over the entire circumference via an annular corner portion 11d. An annular indentation 15 is formed over the entire circumference at this corner portion 11d. The shape of the corner portion 11d before the indentation 15 is formed is shown by a two-dot chain line in FIG. 1.

[0024] With reference to FIGS. 2 to 3(b), while explaining the manufacturing method of the vibration isolation device 10, the details of the corner portion 11d and the indentation 15 will also be explained. FIG. 2 is a cross-sectional view of the cylindrical member 11, the outer cylinder 12, and the mold 30 before mold clamping. FIG. 3(a) is a partially enlarged cross-sectional view of the cylindrical member 11 and the mold 30 showing an enlarged IIIa portion of FIG. 2. FIG. 3(b) is a partially enlarged cross-sectional view of the vibration isolation device 10 and the mold 30 after mold clamping.

[0025] To manufacture the vibration isolator 10, first, in the preparation process, a cylindrical member 11 before the indentation 15 is formed is prepared, and an adhesive is applied to the outer peripheral surface 11b of the cylindrical member 11 and the inner peripheral surface of the outer cylinder 12, respectively. Next, in the holding process, the cylindrical member 11 and the outer cylinder 12 are set in the mold 30, and the mold 30 is clamped. In the subsequent molding process, a molding material of an elastic body is injected into the cavity 33 of the mold 30 to vulcanize and mold the vibration isolation base 13. Thereby, the vibration isolation base 13 is vulcanized and adhered to the cylindrical member 11 and the outer cylinder 12, and the vibration isolator 10 is obtained by opening the mold 30.

[0026] As shown in FIG. 2, the mold 30 includes an upper mold 31 and a lower mold 32. The mold 30 is configured such that the upper mold 31 can move up and down with respect to the lower mold 32 to perform mold clamping (closing) and mold opening. The upper mold 31 and the lower mold 32 are made of a steel material that is sufficiently harder than the cylindrical member 11. A cavity 33, which is a cylindrical space corresponding to the shape of the vibration isolation base 13, is formed between the upper mold 31 and the lower mold 32. Since the upper mold 31 and the lower mold 32 are formed symmetrically in the vertical direction, the upper mold 31 will be described, and the description of the lower mold 32 will be partially omitted.

[0027] The upper mold 31 is formed in a shape in which the cylindrical member 11 and the outer cylinder 12 can be fitted so that the wall surface on the inner peripheral side of the cavity 33 is formed by the cylindrical member 11, and the wall surface on the outer peripheral side of the cavity 33 is formed by the outer cylinder 12. In the portion where the cylindrical member 11 is fitted, the upper mold 31 includes a fitting convex portion 34 inserted into the inner peripheral surface 11c side of the cylindrical member 11, a diameter-facing surface 35 facing the outer peripheral surface 11b of the cylindrical member 11 in the radial direction, and an axial-facing surface 36 facing the end surface 11a of the cylindrical member 11 in the axial direction.

[0028] The base end portion (on the side of the axial facing surface 36) of the fitting convex portion 34 is formed in a columnar shape with an outer diameter substantially the same as the inner diameter of the inner peripheral surface 11c of the cylindrical member 11. The tip end portion (on the side opposite to the axial facing surface 36) of the fitting convex portion 34 is formed in a tapered shape as it moves away from the base end portion. When setting the cylindrical member 11 in the upper die 31 or the lower die 32, the tip end portion makes it easier to insert the fitting convex portion 34 into the cylindrical member 11. Subsequently, when the base end portion of the fitting convex portion 34 is inserted into and fits with the cylindrical member 11, the cylindrical member 11 is positioned in the radial direction with respect to the upper die 31.

[0029] As shown in FIGS. 2 and 3(a), the diameter facing surface 35 is a portion where the cylindrical member 11 fits, and is formed by a cylindrical surface centered on the axis C. The inner diameter of the diameter facing surface 35 is formed to be substantially the same as the maximum value of the outer diameter of the cylindrical member 11 considering dimensional tolerances. Therefore, even if there are individual differences in the cylindrical member 11 within the dimensional tolerances, the cylindrical member 11 can be fitted to the diameter facing surface 35.

[0030] Note that due to individual differences in the cylindrical member 11, the gap formed between the diameter facing surface 35 and the outer peripheral surface 11b of the cylindrical member 11 is formed to be sufficiently narrower (less than half) than the radial dimension of the portion forming the inner film portion 14 of the vibration isolation base 13 in the cavity 33. The maximum value of the gap formed between the diameter facing surface 35 and the outer peripheral surface 11b of the cylindrical member 11 is about 0.2 mm.

[0031] The axial facing surface 36 is an annular portion centered on the axis C and connects the fitting convex portion 34 and the axial facing surface 36 in the radial direction. Further, the axial facing surface 36 is formed by a plane perpendicular to the axis C and is formed substantially parallel to the end face 11a of the cylindrical member 11.

[0032] From the axial facing surface 36, a protrusion 38 protrudes in the axial direction toward the cylindrical member 11. The protrusion 38 is provided at the corner between the axial facing surface 36 and the diameter facing surface 35, that is, it also protrudes in the radial direction from the diameter facing surface 35. The protrusion 38 is an annular member continuous over the entire circumference in the circumferential direction. The protrusion 38 rises in a stepped manner substantially perpendicular to each of the axial facing surface 36 and the diameter facing surface 35, and the cross section including the axis C is formed in a rectangular shape.

[0033] In the holding process, when the cylindrical member 11 and the outer cylinder 12 are set on the lower mold 32 in the mold-opening state where the upper mold 31 and the lower mold 32 are separated, the lower corner 11d of the cylindrical member 11 rests on the projection 38 of the lower mold 32. Further, when the upper mold 31 is placed on this lower mold 32, the projection 38 of the upper mold 31 rests on the upper corner 11d of the cylindrical member 11. This state is the state before mold clamping shown in FIGS. 2 and 3(a).

[0034] Note that the corner 11d is an R surface that smoothly connects the end face 11a and the outer peripheral surface 11b with a curve convex outward in a cross section including the axis C. However, the corner 11d may be not limited to the R surface but also a C surface. The C surface is formed by a straight line where the cross section including the axis C is inclined with respect to the end face 11a and the outer peripheral surface 11b.

[0035] When the upper mold 31 and the lower mold 32 are clamped so as to be in close contact from the state before mold clamping shown in FIGS. 2 and 3(a), as shown in FIG. 3(b), the axially opposed surface 36 comes into close contact with the end face 11a of the cylindrical member 11. At this time, the annular projection 38 is pressed against the corner 11d and bites in, and the cylindrical member 11 is plastically deformed to form an annular indentation 15.

[0036] In the state where the cylindrical member 11 and the outer cylinder 12 are held by the clamped mold 30, a molding process is performed. In the molding process, as described above, an elastic molding material is injected into the cavity 33 facing the outer peripheral surface 11b of the cylindrical member 11 to vulcanize and mold the vibration isolation base 13.

[0037] At this time, due to the pressing of the projection 38 that forms the indentation 15, the space between the mold 30 and the cylindrical member 11 is sealed, so that the elastic molding material can be prevented from infiltrating from the outer peripheral surface 11b side of the cylindrical member 11 to the end face 11a side. As a result, it is possible to make it difficult for burrs formed by the solidification of the infiltrated molding material to occur on the end face 11a of the cylindrical member 11. Thereby, the process of removing burrs from the vibration isolation device 10 after the molding process can be simplified or the process can be omitted.

[0038] Even without checking the formation process of the indentation 15, it is possible to confirm whether the dent formed in the cylindrical member 11 is the indentation 15 or not, based on the comparison between the material density near the indentation 15 and the material density at a position away from the indentation 15, the state of the metal flow around the indentation 15, the swelling of the material surface around the indentation 15, etc. That is, even without checking the manufacturing method of the vibration isolator 10, by checking the vibration isolator 10 after manufacturing, it can be seen that the position of the indentation 15 was sealed during the molding of the vibration isolation base 13, and it can be seen that burrs were less likely to occur on the end face 11a during the molding.

[0039] Also, since the indentation 15 is formed in substantially the same shape as the protrusion 38, the shape of the protrusion 38 can be known without checking the manufacturing method of the vibration isolator 10. Specifically, the indentation 15 is formed by crushing the entire corner portion 11d toward the central side in the axial direction. Therefore, since the area sealed by the protrusion 38 is large during the molding of the vibration isolation base 13, it is possible to further suppress the molding material of the elastic body from penetrating from the outer peripheral surface 11b side of the cylindrical member 11 over the corner portion 11d to the end face 11a side. Thus, it is possible to make it more difficult for burrs to occur on the end face 11a.

[0040] The indentation 15 is recessed in a stepped shape substantially perpendicular to the end face 11a. That is, since this step with respect to the end face 11a is formed by shear deformation accompanying the pressing of the protrusion 38, it is possible to make it difficult for the material surface around the indentation 15 to swell on the end face 11a and easy to occur on the outer peripheral surface 11b. As a result, when the end face 11a is brought into close contact with the mating member 21 and fastened, the fastening performance can be ensured by ensuring the flatness of the end face 11a. Note that the area of the end face 11a of the cylindrical member 11 is designed to be a size that can ensure desired fastening performance and strength in a state where the indentation 15 is formed.

[0041] Furthermore, the indentation 15 is formed by the corner between a plane substantially perpendicular to the end face 11a and a plane substantially parallel to the end face 11a. Therefore, since the protrusion 38 formed by the angle between the plane substantially perpendicular to the end face 11a and the plane substantially parallel to the end face 11a is pressed against the cylindrical member 11 in the axial direction to form the indentation 15, it is difficult for radial inward stress to occur in the cylindrical member 11 from the protrusion 38 during its formation. Therefore, it is possible to suppress the reduction in the diameter of the cylindrical member 11 associated with the stress.

[0042] Next, a second embodiment will be described with reference to FIG. 4(a). In the first embodiment, the case where the indentation 15 that is recessed in a stepped shape substantially perpendicular to the end face 11a is formed in the cylindrical member 11 was described. In contrast, in the second embodiment, the case where the indentation 42 that is inclined with respect to the end face 11a and the outer peripheral face 11b is formed in the cylindrical member 41 will be described. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and the following description thereof will be omitted.

[0043] FIG. 4(a) is a partially enlarged cross-sectional view of the cylindrical member 41 and the mold 45 in the second embodiment. The cylindrical member 41 and the mold 45 are formed identically to the cylindrical member 11 and the mold 30 in the first embodiment, except that the shapes of the indentation 42 and the protrusion 46 are different. An anti-vibration device is formed by vulcanizing and adhering the anti-vibration base 13 in the first embodiment to the outer peripheral face 11b of the cylindrical member 41.

[0044] The protrusion 46 of the mold 45 protrudes axially from the axially opposing face 36 toward the cylindrical member 41, and is provided on each of the upper mold 31 and the lower mold 32. The protrusion 46 is provided at the corner of the axially opposing face 36 and the radially opposing face 35, that is, it also protrudes radially from the radially opposing face 35. The protrusion 46 is an annular member that is continuous over the entire circumference in the circumferential direction.

[0045] The protrusion 46 has an inclined face 47 that obliquely connects the axially opposing face 36 and the radially opposing face 35, and a cross-section including the axis C is formed in a right-angled triangle shape. When the mold 45 is clamped and the inclined face 47 of the protrusion 46 is pressed against the corner 11d of the cylindrical member 41, the cylindrical member 41 is plastically deformed and an annular indentation 42 is formed at the corner 11d. As a result, similar to the first embodiment, when the anti-vibration base 13 is molded, the space between the mold 45 and the cylindrical member 41 is sealed by the pressing of the protrusion 46 that forms the indentation 42, so that it is difficult to generate burrs on the end face 11a of the cylindrical member 41.

[0046] The indentation 42 inclines toward the axially central side as it goes toward the radially outer side. Therefore, even without confirming the formation process of the indentation 42, it can be understood that the indentation 42 is formed by the inclined face 47 of the similarly inclined protrusion 46.

[0047] Here, when forming the indentation 42 by the protrusion 46, depending on the individual difference in the axial length of the cylindrical member 41, the axially opposing surface 36 of the mold 45 may not be in close contact with the end surface 11a. At this time, with the shape of the protrusion 38 as in the first embodiment, if the protruding amount of the protrusion 38 from the axially opposing surface 36 is small, the protrusion 38 may not bite into the cylindrical member 11, and there is a risk that the indentation 15 cannot be formed. That is, when molding the vibration-proof base 13, depending on the dimensional accuracy of the cylindrical member 11, there is a risk that the sealing performance when forming the indentation 15 is likely to decrease according to the individual difference.

[0048] On the other hand, in the second embodiment, when molding the vibration-proof base 13, even if the axially opposing surface 36 is not in close contact with the end surface 11a, the inclined surface 47 of the protrusion 46 partially bites into the corner portion 11d of the cylindrical member 41. That is, the individual difference in the axial length of the cylindrical member 41 can be absorbed by the inclined surface 47 of the protrusion 46, so that it is possible to suppress the sealing performance from decreasing according to the individual difference when forming the indentation 42.

[0049] In the second embodiment, the inclination angle θ of the inclined surface 47 and the indentation 42 with respect to the axially opposing surface 36 and the end surface 11a is set to 45 degrees or less. Thereby, when forming the indentation 42, it is easy to avoid a state in which the cylindrical member 41 is press-fitted into the inclined surface 47 of the annular protrusion 46. Thus, it is easy to demold the cylindrical member 41 from the mold 45, and it is possible to suppress the reduction in the diameter of the cylindrical member 41 due to the press-fitting. Further, for improving the demoldability and further suppressing the reduction in the diameter of the cylindrical member 41, the inclination angle θ is preferably 40 degrees or less, and more preferably 30 degrees or less.

[0050] However, if this inclination angle θ is too small, it becomes difficult to absorb the individual difference in the axial length of the cylindrical member 41 by the inclined surface 47. For absorbing this individual difference, the inclination angle θ is preferably 10 degrees or more, and more preferably 20 degrees or more.

[0051] Also, the inclination angle θ may be 45 degrees or more. In this case, individual differences in the axial length of the cylindrical member 41 can be easily absorbed by the inclined surface 47. Furthermore, where the depth of the indentation 42 varies according to individual differences in the axial length of the cylindrical member 41, the greater the inclination angle θ, the smaller the variation in the radial depth of the indentation 42 can be made. If this variation in the radial depth is small, it is easy to ensure the area of the end face 11a, and the influence on the fastening performance can be suppressed. For suppressing this influence, the inclination angle θ is preferably 50 degrees or more, and more preferably 60 degrees or more.

[0052] However, if this inclination angle θ is too large, there is a possibility that the cylindrical member 41 pressed against the inclined surface 47 will only elastically deform in the radial direction and the indentation 42 will not be formed. Therefore, for the formation of the indentation 42, the inclination angle θ is preferably 80 degrees or less, and more preferably 70 degrees or less.

[0053] Next, a third embodiment will be described with reference to FIG. 4(b). In the first embodiment, the case where the indentation 15 is formed at the corner portion 11d of the cylindrical member 11 was described. In contrast, in the third embodiment, the case where the indentation 52 is formed only on the end face 11a of the cylindrical member 51 will be described. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and the following description thereof will be omitted.

[0054] FIG. 4(b) is a partially enlarged cross-sectional view of the cylindrical member 51 and the mold 55 in the third embodiment. The cylindrical member 51 and the mold 55 are formed identically to the cylindrical member 11 and the mold 30 in the first embodiment, except that the shapes of the indentation 52 and the protrusion 56 are different. An anti-vibration device is formed by vulcanizing and adhering the anti-vibration base 13 in the first embodiment to the outer peripheral surface 11b of the cylindrical member 51.

[0055] The protrusion 56 of the mold 55 protrudes axially from the axially facing surface 36 toward the cylindrical member 51, and is provided on each of the upper mold 31 and the lower mold 32. The protrusion 56 is provided at a position away from the radially facing surface 35. The protrusion 56 is an annular member continuous over the entire circumference in the circumferential direction, and the cross-section including the axis C is semi-circular.

[0056] When the mold 55 is clamped and this projection 56 is pressed against the end face 11a of the cylindrical member 51, the cylindrical member 51 plastically deforms and an annular indentation 52 is formed only on the end face 11a. Thus, similar to the first and second embodiments, when the vibration-proof base 13 is molded, as the projection 56 presses to form the indentation 52, the space between the mold 55 and the cylindrical member 51 is sealed, making it difficult to generate burrs on the end face 11a.

[0057] Also, similar to the first and second embodiments, from the shape and position of the indentation 52, even without checking the formation process of the indentation 52, it can be known that the indentation 52 was formed by the projection 56 at the corresponding shape and position. The indentation 52 (projection 56) is arranged closer to the corner portion 11d than the radial center of the end face 11a, and is arranged as close as possible to the corner portion 11d. Thereby, the area of the end face 11a radially inside the indentation 52 can be ensured, and the fastening performance corresponding to that area can be ensured.

[0058] However, in the third embodiment, it is difficult to suppress the formation of burrs on the end face 11a radially outside the indentation 52. Even in this case, since the range where burrs are formed can be limited, the process of removing burrs can be simplified or the time of that process can be shortened.

[0059] On the other hand, in the first embodiment etc., since the indentation 15 is formed at the corner portion 11d, when the vibration-proof base 13 is molded, it is possible to further suppress the molding material of the elastic body from penetrating from the outer peripheral surface 11b side of the cylindrical member 11 over the corner portion 11d to the end face 11a side. As a result, it is possible to more difficultly generate burrs on the end face 11a.

[0060] Also, for example, in the first embodiment where the indentation 15 is formed at the corner portion 11d, when the cylindrical member 11 is displaced radially with respect to the projection 38 during the molding of the vibration-proof base 13, the size of the indentation 15 formed in the cylindrical member 11 may become non-uniform in the circumferential direction. Thereby, the sealing performance during the formation of the indentation 15 may become non-uniform in the circumferential direction.

[0061] In contrast, in the third embodiment, the indentation 52 is formed only on the end face 11a. Therefore, when the cylindrical member 51 is displaced in the radial direction with respect to the protrusion 56 during the molding of the vibration isolation base 13, it is easy to make the size of the indentation 52 uniform in the circumferential direction. As a result, it is easy to make the sealing performance uniform in the circumferential direction when forming the indentation 52, and it is difficult to generate burrs on the end face 11a.

[0062] Next, a fourth embodiment will be described with reference to FIG. 5(a). In the second embodiment, the case where the indentation 42 that inclines toward the central side in the axial direction as it goes toward the outer side in the radial direction is formed on the entire corner portion 11d has been described. In contrast, in the fourth embodiment, the case where the similarly inclined indentation 63 is formed on a part of the corner portion 62 of the cylindrical member 61 will be described. Note that the same parts as those in the first and second embodiments are denoted by the same reference numerals, and the following description thereof will be omitted.

[0063] FIG. 5(a) is a partially enlarged cross-sectional view of the cylindrical member 61 and the mold 65 in the fourth embodiment. The cylindrical member 61 and the mold 65 are formed in the same manner as the cylindrical member 11 and the mold 30 in the first embodiment, except that the shapes of the corner portion 62, the indentation 63, and the protrusion 66 are different. The vibration isolation device is formed by vulcanizing and adhering the vibration isolation base 13 in the first embodiment to the outer peripheral surface 11b of the cylindrical member 61.

[0064] Further, the protrusion 66 is formed substantially the same as the protrusion 46, except that the inclination angle θ of the inclined surface 47 of the protrusion 46 in the second embodiment is changed. The inclination angle θ of the inclined surface 67 of the protrusion 66 is greater than 45 degrees with respect to the axially facing surface 36 and the end face 11a. The inclination angle θ of the inclined surface 67 is, for example, about 60 degrees.

[0065] The corner portion 62 of the cylindrical member 61 before clamping the mold 65 is the C surface described above in the first embodiment, and the inclination angle with respect to the end face 11a is about 45 degrees. When the mold 65 is clamped, since the inclination angle θ of the inclined surface 67 is greater than the inclination angle of the corner portion 62, the inclined surface 67 is pressed against the corner between the corner portion 62 and the outer peripheral surface 11b, and the cylindrical member 61 is plastically deformed. As the amount of this plastic deformation increases, the indentation 63 formed by the inclined surface 67 spreads from the corner between the corner portion 62 and the outer peripheral surface 11b toward the end face 11a side.

[0066] Since the indentation 63 is formed at the corner 62 in this way, during the molding of the vibration-proof base 13, similar to the first embodiment and the like, as the protrusion 66 that forms the indentation 63 presses, the space between the mold 65 and the cylindrical member 61 is sealed, making it difficult to generate burrs on the end face 11a of the cylindrical member 61.

[0067] Also, in the fourth embodiment, the indentation 63 is provided on a part of the outer peripheral surface 11b side of the corner 62, and the composition deformation amount (for example, about 0.15 mm) of the cylindrical member 61 is adjusted so that the corner 62 where the indentation 63 is not provided remains on the end face 11a side. Therefore, the swelling around the indentation 63 during its formation can be absorbed by a part of the end face 11a side of the corner 62 where the indentation 63 is not provided, making it difficult for the end face 11a to bulge partially. As a result, when the end face 11a is brought into close contact with the mating member 21 and fastened, the fastening performance can be ensured by ensuring the flatness of the end face 11a.

[0068] While maintaining the plastic deformation amount from the original corner 62 at about 0.15 mm or the like to ensure sealing performance, when the inclination angle θ of the inclined surface 67 is reduced, in the cross-section including the axis C, the width W1 of the corner 62 of the part where the indentation 63 is not provided becomes narrower, and the width W2 of the indentation 63 becomes wider. In other words, if the width W1 is narrower than the width W2, it is easier to reduce the inclination angle θ of the inclined surface 67 during the formation of the indentation 63. As a result, during the formation of the indentation 63, it is easy to avoid a state where the cylindrical member 61 is press-fitted into the inclined surface 67 of the annular protrusion 66, so that it is easy to demold the cylindrical member 61 from the mold 65 and suppress the reduction in the diameter of the cylindrical member 61 due to press-fitting.

[0069] On the other hand, if the width W1 is wider than the width W2, the plastic deformation amount in the radial direction of the cylindrical member 61 associated with the formation of the indentation 63 can be reduced. As a result, it is possible to suppress the overall reduction in the diameter of the cylindrical member 61 due to the formation of the indentation 63. Furthermore, if the width W1 is wider than the width W2, it is easier to increase the inclination angle θ of the inclined surface 67 during the formation of the indentation 63. Therefore, as described above in the second embodiment, it is possible to suppress the influence of the individual difference in the axial length of the cylindrical member 61 on the fastening performance.

[0070] Next, the fifth embodiment will be described with reference to FIG. 5(b). In the fourth embodiment, the case where the indentation 63 is formed in a part of the outer peripheral surface 11b side of the corner portion 62 was described. In contrast, in the fifth embodiment, the case where the indentation 72 is formed in a part of the end surface 11a side of the corner portion 62 will be described. Note that the same parts as those in the first to fourth embodiments are denoted by the same reference numerals, and the following description thereof will be omitted.

[0071] FIG. 5(b) is a partially enlarged cross-sectional view of the cylindrical member 71 and the mold 75 in the fifth embodiment. The cylindrical member 71 and the mold 75 are formed in the same manner as the cylindrical member 11 and the mold 30 in the first embodiment, except that the shapes of the corner portion 62, the indentation 72, and the protrusion 76 are different. The anti-vibration device is formed by vulcanizing and bonding the anti-vibration base 13 in the first embodiment to the outer peripheral surface 11b of the cylindrical member 71.

[0072] The corner portion 62 of the cylindrical member 71 is the same as the corner portion 62 of the cylindrical member 61 in the fourth embodiment. Further, the protrusion 76 of the mold 75 is formed substantially the same as the protrusions 46, 66 except that the inclination angle θ of the inclined surfaces 47, 67 of the protrusions 46, 66 in the second and fourth embodiments is changed. The inclined surface 77 of the protrusion 76 has an inclination angle θ with respect to the axially facing surface 36 and the end surface 11a that is less than 45 degrees. The inclination angle θ of the inclined surface 77 is, for example, about 30 degrees.

[0073] When the mold 75 is clamped, since the inclination angle θ of the inclined surface 77 is smaller than the inclination angle of the corner portion 62, the inclined surface 77 is pressed against the corner between the corner portion 62 and the end surface 11a, and the cylindrical member 71 is plastically deformed. As the amount of this plastic deformation increases, the indentation 72 formed by the inclined surface 77 spreads from the corner between the corner portion 62 and the end surface 11a toward the outer peripheral surface 11b side.

[0074] In this way, since the indentation 72 is formed in the corner portion 62, similar to the first embodiment and the like, when the anti-vibration base 13 is molded, the pressing of the protrusion 76 that forms the indentation 72 seals the space between the mold 75 and the cylindrical member 71, so that it is difficult to generate burrs on the end surface 11a of the cylindrical member 71.

[0075] In the fifth embodiment, an indentation 72 is provided on a part of the end face 11a side of the corner portion 62, and the composition deformation amount (for example, about 0.15 mm) of the cylindrical member 71 is adjusted so that the corner portion 62 where the indentation 72 is not provided remains on the outer peripheral surface 11b side. Therefore, in other words, when the indentation 72 is provided partially in this way, it can be seen that the indentation 72 is formed by the inclined surface 77 with a small inclination angle θ. Therefore, when the indentation 72 is formed, it is easy to avoid a state in which the cylindrical member 71 is press-fitted into the inclined surface 77 of the annular protrusion 76. Thus, it is easy to demold the cylindrical member 71 from the mold 75, and the reduction in the diameter of the cylindrical member 71 due to the press-fitting can be suppressed.

[0076] While maintaining the plastic deformation amount from the original corner portion 62 at about 0.15 mm or the like to ensure the sealing performance, if the inclination angle θ of the inclined surface 77 is increased, in the cross section including the axis C, the width W3 of the corner portion 62 of the portion where the indentation 72 is not provided becomes narrower, and the width W4 of the indentation 72 becomes wider. In other words, if the width W3 is narrower than the width W4, it is easy to increase the inclination angle θ of the inclined surface 77 when the indentation 72 is formed. As a result, as described above in the second embodiment, it is possible to suppress the influence of the individual difference in the axial length of the cylindrical member 71 on the fastening performance.

[0077] Although the present invention has been described based on the embodiments, it can be easily inferred that the present invention is not limited to the above embodiments at all, and various improvements and modifications are possible without departing from the gist of the present invention. For example, the counterpart member 21 to which the cylindrical members 11, 41, 51, 61, 71 are fastened is not limited to the vibration receiving side, and the counterpart member 21 may be on the vibration source side.

[0078] In each of the above embodiments, the case where the vibration isolation device 10 is configured by connecting the outer peripheral surfaces 11b of the cylindrical members 11, 41, 51, 61, 71 and the outer cylinder 12 with the vibration isolation base 13 has been described, but it is not necessarily limited to this. For example, the outer cylinder 12 may be omitted, and a vibration isolation device may be formed by vulcanizing and adhering the vibration isolation base 13 to the outer peripheral surfaces 11b of the cylindrical members 11, 41, 51, 61, 71. This vibration isolation device is used, for example, with the vibration isolation base 13 sandwiched in the radial direction by a pair of semi-cylindrical brackets.

[0079] The cylindrical members 11, 41, 51, 61, and 71 only need to be cylindrical and surround the axis C, and are not limited to a circular cylinder. For example, in a cross-section perpendicular to the axis C, the outer peripheral surface 11b or the inner peripheral surface 11c of the cylindrical members 11, 41, 51, 61, and 71 may be polygonal, elliptical, or oblong. Oppositely, the annular protrusions 38, 46, 56, 66, and 76 may be polygonal, elliptical, or oblong.

[0080] In the above-described fourth and fifth embodiments, the case where the corner portion 62 of the cylindrical members 61 and 71 is the C surface has been described, but it is not necessarily limited to this, and it may be the R surface. However, when the corner portion 62 is the C surface, the boundary portion between the end surface 11a or the outer peripheral surface 11b and the corner portion 62 is angular, so a part of the corner portion 62 can be easily plastically deformed by the inclined surfaces 67 and 77 of the protrusions 66 and 76, and the indentations 63 and 72 can be easily formed.

[0081] The shapes of the protrusions 38, 46, 56, 66, and 76 and the indentations 15, 42, 52, 63, and 72 shown in the above-described embodiments are examples, and other shapes may be used. For example, in a cross-section including the axis C, the surface (such as an inclined surface) pressed against the cylindrical members 11, 41, 51, 61, and 71 among the protrusions and the indentations may be formed by a curve, or may be formed by a combination of a plurality of straight lines and curves.

Explanation of Reference Numerals

[0082] 10 Vibration isolator 11, 41, 51, 61, 71 Cylindrical member 11a End surface 11b Outer peripheral surface 11d, 62 Corner portion 13 Vibration isolation base 15, 42, 52, 63, 72 Indentation 30, 45, 55, 65, 75 Mold 33 Cavity 36 Axially facing surface 38, 46, 56, 66, 76 Protrusion

Claims

1. A cylindrical tubular member in which an axial end face and an outer peripheral face are connected via a corner, and a vibration isolation base made of an elastic body vulcanized and adhered to the outer peripheral face of the tubular member, characterized in that an annular indentation that is continuous over the entire circumference is formed at the corner or on the corner side of the radial center of the end face. A vibration isolation device

2. The vibration isolation device according to claim 1, characterized in that the indentation is formed at the corner.

3. The vibration isolation device according to claim 2, characterized in that the indentation inclines toward the axial center side as it goes toward the outer side in the radial direction.

4. The vibration isolation device according to claim 3, characterized in that the indentation is provided on a part of the outer peripheral face side of the corner.

5. The vibration isolation device according to claim 3, characterized in that the indentation is provided on a part of the end face side of the corner.

6. A method for manufacturing a vibration isolation device including a cylindrical tubular member in which an axial end face and an outer peripheral face are connected via a corner, and a vibration isolation base made of an elastic body vulcanized and adhered to the outer peripheral face of the tubular member, the method comprising: a holding step of sandwiching and holding the tubular member with a mold from both axial sides; and a molding step of injecting a molding material of an elastic body into a cavity of the mold in which the tubular member is held in the holding step to vulcanize and mold the vibration isolation base, characterized in that the mold includes an annular axially facing surface that faces the end face of the tubular member in the axial direction in the holding step, and an annular protrusion that protrudes from the axially facing surface toward the tubular member and is continuous over the entire circumference in the circumferential direction of the axially facing surface, and in the holding step, an annular indentation is formed by pressing the protrusion against the corner or on the corner side of the radial center of the end face. A method for manufacturing a vibration isolation device

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