Vibration isolation device and manufacturing method thereof

Abstract

To provide a vibration isolation device capable of preventing occurrence of a molding defect and a manufacturing method thereof.SOLUTION: A vibration isolation base 11 has an elastic injection mark portion 15 formed on one axial end side, and a plurality of metal fitting receiving marks 16a and 16b formed circumferentially spaced from each other on the other axial end side, and exposing a metal fitting 20 to an outside. When a position opposite the injection mark portion 15 with respect to an axis C is taken as 0°, the plurality of metal fitting receiving marks 16a and 16b is located outside of a range of angle θ from minus 10°to 10°. Therefore, when the vibration isolation base 11 is molded, the metal fitting 20 is supported by a mold 30 by using metal fitting receiving portions 33a and 33b at positions of the metal fitting receiving marks 16a and 16b, and occurrence of the molding defects such as bare spots in the vibration isolation base 11 can be prevented.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vibration isolator and a method for manufacturing the same, and more particularly to a vibration isolator and a method for manufacturing the same that are less likely to cause molding defects.

Background Art

[0002] Conventionally, a method for manufacturing a vibration isolator in which a metal fitting is embedded over the entire circumference inside a vibration isolation base body has been known. In this method, an annular metal fitting is supported by a plurality of metal fitting receiving portions in a lower mold, and an elastic body is injected into the upper mold and the lower mold from an injection port in the upper mold to form an annular vibration isolation base body (Patent Document 1). Since one axial end side of the vibration isolation base body is formed by the upper mold, an injection trace portion due to the trace of the injection port is formed on that one end side. Since the other axial end side of the vibration isolation base body is formed by the lower mold, a plurality of metal fitting receiving traces for exposing the metal fitting from the vibration isolation base body to the outside are formed as traces of the plurality of metal fitting receiving portions on the other end side. Further, since the plurality of metal fitting receiving portions are separated from each other in the circumferential direction, the plurality of metal fitting receiving traces are also formed separated from each other in the circumferential direction.

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-described conventional technique of embedding an annular metal fitting in an annular vibration isolation base body, depending on the positional relationship between the injection port (injection trace portion) and the plurality of metal fitting receiving portions (metal fitting receiving traces), there is a problem that molding defects such as bare (depressions) are likely to occur on the surface of the vibration isolation base body after molding.

[0005] The present invention has been made to solve the above-described problems, and an object thereof is to provide a vibration isolator and a method for manufacturing the same that are less likely to cause molding defects.

Means for Solving the Problems

[0006] To achieve this object, the vibration isolator of the present invention includes an annular vibration isolation base made of an elastic body and an annular fitting embedded in the interior of the vibration isolation base over the entire circumference. The vibration isolation base includes an injection trace portion of the elastic body formed on one axial end side, and a plurality of fitting receiving traces formed on the other axial end side at a circumferential distance from each other to expose the fitting to the outside. At an angle centered on the axis of the fitting, when the position of the antipole of the injection trace portion with respect to the axis is set to 0°, a plurality of the fitting receiving traces are located outside the range of -10° to 10°.

[0007] A method for manufacturing a vibration isolator of the present invention is a method for manufacturing a vibration isolator including an annular vibration isolation base made of an elastic body and an annular fitting embedded in the interior of the vibration isolation base over the entire circumference. The method includes a holding step of holding the fitting in a mold, and a molding step of injecting a molding material of an elastic body from an injection port into the mold after the holding step to vulcanize and mold the vibration isolation base. The mold includes an upper mold having the injection port and molding one axial end side of the vibration isolation base, and a lower mold having a plurality of fitting receiving portions that support the other axial end side of the fitting and are circumferentially separated from each other and molding the other axial end side of the vibration isolation base. At an angle centered on the axis of the fitting, when the position of the antipole of the injection port with respect to the axis is set to 0°, a plurality of the fitting receiving portions are located outside the range of -10° to 10°.

Effect of the Invention

[0008] According to the vibration isolator described in claim 1, the vibration isolation base includes an injection trace portion of the elastic body formed on one axial end side, and a plurality of fitting receiving traces formed on the other axial end side at a circumferential distance from each other to expose the fitting to the outside. From this, it can be seen that when molding the vibration isolation base using the upper mold and the lower mold, the fitting is supported by the fitting receiving portion at the position of the plurality of fitting receiving traces, and the molding material of the elastic body is injected between the upper mold and the lower mold from the injection port provided in the upper mold at the position of the injection trace portion.

[0009] The molding material of the elastic body injected from the position of the injection trace of Atobe (injection port) advances while being divided into both circumferential sides between the upper mold and the lower mold. After that, when the position of the antipole of the injection trace with respect to the axis is set to 0° at the angle centered on the axis of the metal fitting, the molding materials of the elastic body advancing from both circumferential sides are likely to merge within the range of -10° to 10°. If there is a metal fitting receiving part within this range, the flow pattern of the molding material of the elastic body becomes complicated, and molding defects such as burrs are likely to occur in the vibration isolation base. On the other hand, if there are a plurality of metal fitting receiving traces outside the range of -10° to 10° of the vibration isolation base after molding, it can be said that there are a plurality of metal fitting receiving parts outside that range during the molding of the vibration isolation base, so it is possible to make it difficult for molding defects such as burrs to occur in the vibration isolation base.

[0010] 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. When molding the vibration isolation base, if the number of metal fitting receiving parts for supporting the metal fitting with the lower mold is 4 or more, there is a possibility that the annular metal fitting may float from any one or more of them. On the other hand, since the number of metal fitting receiving traces formed on the other end side in the axial direction of the vibration isolation base is 3, it can be seen that the number of metal fitting receiving parts was 3 when molding the vibration isolation base. Therefore, when molding the vibration isolation base, it is possible to make it difficult for the annular metal fitting to float from each of the three metal fitting receiving parts, and it is possible to suppress the flow of the molding material of the elastic body from becoming unstable due to this floating. As a result, it is possible to make it more difficult for molding defects such as burrs to occur in the vibration isolation base.

[0011] According to the vibration isolation device described in claim 3, in addition to the effects exhibited by the vibration isolation device described in claim 1, the following effects are exhibited. The metal fitting receiving traces formed on the other end side in the axial direction of the vibration isolation base are arranged symmetrically with respect to the virtual plane including the axis and the injection trace. Thereby, when molding the vibration isolation base, it is possible to make the advancing directions of the molding materials of the elastic body injected from the position of the injection trace uniform on both circumferential sides. As a result, it is possible to stabilize the merging manner of these molding materials, and it is possible to make it more difficult for molding defects such as burrs to occur in the vibration isolation base.

[0012] According to the vibration isolator described in claim 4, in addition to the effects achieved by the vibration isolator described in any one of claims 1 to 3, the following effects are achieved. The metal fitting includes a cylindrical tubular portion surrounding the axis, and an annular flange portion extending radially outward from an end portion on one axial end side of the tubular portion. The vibration isolation base includes a cylindrical elastic tubular portion in which the tubular portion is embedded, and an elastic flange portion extending radially outward from an end portion on one axial end side of the elastic tubular portion and in which the flange portion is embedded. When embedding a metal fitting with such a relatively complex shape into a vibration isolation base with a similar shape, there is a risk that molding defects are likely to occur during the molding of the vibration isolation base.

[0013] Further, in the elastic tubular portion, a plurality of metal fitting receiving traces are formed so that an end portion on the other axial end side of the tubular portion is exposed. Since the end portion on the other axial end side of the tubular portion is the farthest from the injection trace portion in the axial direction, there is a risk that molding defects are likely to occur at that end portion. However, even for a shape where molding defects are likely to occur, since a plurality of metal fitting receiving traces are not located at the position opposite to the injection trace portion with respect to the axis, it is possible to sufficiently prevent molding defects from occurring during the molding of the vibration isolation base.

[0014] According to the vibration isolator described in claim 5, in addition to the effects achieved by the vibration isolator described in claim 4, the following effects are achieved. A plurality of through holes are formed to penetrate the flange portion in the axial direction. When molding the vibration isolation base, since the molding material of the elastic body is injected between the upper mold and the lower mold from the position of the injection trace portion, the injection pressure applied to the flange portion is likely to increase in the vicinity of that position. If a through hole is located in this vicinity, there is a risk that the flange portion will be damaged starting from the through hole. However, when the position opposite to the injection port with respect to the axis is set to 0° at an angle centered on the axis, since a plurality of through holes are located within the range of -170° to 170° (outside the vicinity of the position of the injection trace portion), damage to the flange portion starting from the through hole can be suppressed.

[0015] According to the method for manufacturing the vibration isolator described in claim 6, in the holding step, the other end side in the axial direction of the fitting is supported by a plurality of fitting receiving portions of the lower mold, and the fitting is held in the mold. In the subsequent molding step, a molding material of the elastic body is injected into the mold from the injection port of the upper mold to vulcanize and mold the vibration isolation base. At this time, the other end side in the axial direction of the vibration isolation base is molded by the lower mold, and one end side in the axial direction of the vibration isolation base is molded by the upper mold. When the position of the antipole of the injection port with respect to the axis is set to 0° at an angle centered on the axis of the fitting, since there are a plurality of fitting receiving portions outside the range of -10° to 10°, similar to the effect exhibited by the vibration isolator described in claim 1, it is possible to hardly cause molding defects such as burrs in the vibration isolation base.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. FIG. 1(a) is a plan view of the vibration isolator 10 in the first embodiment. FIG. 1(b) is a bottom view of the vibration isolator 10. FIG. 2(a) is a front view of the vibration isolator 10 as viewed in the direction of arrow IIa in FIG. 1(a). FIG. 2(b) is a rear view of the vibration isolator 10 as viewed in the direction of arrow IIb in FIG. 1(a). FIG. 3(a) is a front view of the fitting 20 embedded in the vibration isolator 10. FIG. 3(b) is a bottom view of the fitting 20 as viewed in the direction of arrow IIIb in FIG. 3(a). FIG. 4 is a cross-sectional view of the vibration isolator 10 and the mold 30 taken along line IV-IV in FIG. 1(b).

[0018] The arrows U, D, L, R, F, and B in each drawing indicate the upward, downward, leftward, rightward, forward, and backward directions of the vibration isolator 10, respectively. Note that the vertical, horizontal, and front-rear directions of the vibration isolator 10 do not necessarily coincide with the vertical, horizontal, and front-rear directions of the vehicle on which the vibration isolator 10 is mounted.

[0019] The vibration isolator 10 is a spring seat trapezoid for reducing vibrations transmitted from the wheel side to the vehicle body side via a coil spring, and is attached to the upper end of the coil spring. As shown in FIG. 1(a) and the like, the vibration isolator 10 is formed in a substantially annular shape having an axis C. The axial direction of this axis C is the vertical direction, one end side in the axial direction is upward, and the other end side in the axial direction is downward. Hereinafter, 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 explanation.

[0020] The vibration isolator 10 includes an annular vibration isolation base body 11 made of an elastic body such as rubber or thermoplastic elastomer, and an annular fitting 20 embedded in the entire circumference inside the vibration isolation base body 11. As shown in FIGS. 3(a) and 3(b), the fitting 20 includes a cylindrical tubular portion 21 surrounding the axis C, and an annular flange portion 22 extending radially outward from the upper end of the tubular portion 21. The tubular portion 21 and the flange portion 22 are integrally formed by a metal plate.

[0021] The cylindrical portion 21 is a substantially cylindrical member centered on the axis C. Four through-holes 23 are formed to penetrate in the radial direction at approximately the center in the vertical direction of the cylindrical portion 21. The four through-holes 23 are arranged at equal intervals in the circumferential direction and are respectively provided on the front, rear, left, and right of the fitting 20.

[0022] The lower end of the cylindrical portion 21 has its left half formed substantially perpendicular to the axis C, and its right half is inclined upward as it goes rightward. Further, the vicinity of the lower end of the cylindrical portion 21 is curved radially inward over the entire circumference (see Fig. 4). The upper end of the cylindrical portion 21 is curved radially outward toward the flange portion 22 (see Fig. 4).

[0023] The flange portion 22 is a substantially annular member centered on the axis C and is formed in a plate shape perpendicular to the axis C. Four through-holes 24 are formed to penetrate in the vertical direction at approximately the center in the radial direction of the flange portion 22. The four through-holes 24 are arranged at equal intervals in the circumferential direction and are respectively provided at the right front, right rear, left rear, and left front of the fitting 20. That is, the through-holes 23 of the cylindrical portion 21 and the through-holes 24 of the flange portion 22 are arranged alternately and at equal intervals in the circumferential direction.

[0024] A plurality of recesses are formed on the outer peripheral edge of the flange portion 22. In the recesses, there are a pair of mark recesses 25 provided on the left side of the flange portion 22 and four installation recesses 26 respectively provided at the right front, right rear, left rear, and left front of the flange portion 22.

[0025] The pair of mark recesses 25 are formed by notching the outer peripheral edge of the flange portion 22 in a substantially U shape in a vertical view and are slightly separated from each other in the circumferential direction. The mark recesses 25 are marks for allowing an operator to recognize the orientation when setting the fitting 20 in the mold 30 (see Fig. 4) during the manufacture of the vibration isolator 10.

[0026] The installation recesses 26 are curves that are continuous with the outer peripheral edge of the flange portion 22 via an inflection point in a vertical view. Four through-holes 24 are respectively arranged between the four installation recesses 26 and the axis C.

[0027] As shown in FIGS. 1(a) to 2(b) and FIG. 4, the vibration isolation base 11 includes a cylindrical elastic cylinder portion 12 surrounding the axis C, an annular elastic flange portion 13 extending radially outward from the upper end of the elastic cylinder portion 12, a mounting portion 14 protruding upward from the right side of the upper surface 13a of the elastic flange portion 13, and an injection trace portion 15 provided at the upper end of the mounting portion 14. These respective portions are integrally formed by an elastic body.

[0028] The mounting portion 14 is a substantially cylindrical portion that is fitted into a recess of a bracket on the vehicle body side when the vibration isolation device 10 is mounted on the vehicle body side. The upper end side of the mounting portion 14 is tapered to reduce the diameter, making it easier to fit into the recess of the bracket. Further, a plurality of claws protrude from the outer peripheral surface of the mounting portion 14 to prevent the mounting portion 14 from coming out of the recess.

[0029] The injection trace portion 15 is a portion protruding from the upper end of the mounting portion 14 and is formed in a circular shape when viewed in the vertical direction. In each drawing, the injection trace portion 15 is exaggeratedly shown, but actually, the injection trace portion 15 slightly protrudes from the upper end of the mounting portion 14. Also, the injection trace portion 15 may be formed by the inside of an annular recess provided at the upper end of the mounting portion 14.

[0030] The elastic cylinder portion 12 is a substantially cylindrical member centered on the axis C, and a cylinder portion 21 is embedded therein. To facilitate removing the elastic cylinder portion 12 from the mold 30, the inner peripheral surface 12b of the elastic cylinder portion 12 tapers in diameter from both sides in the vertical direction toward the center (see FIG. 4). The outer peripheral surface 12c of the elastic cylinder portion 12 is formed in a cylindrical surface shape centered on the axis C.

[0031] At the lower end 12a of the elastic cylinder portion 12, three fitting receiving traces 16a, 16b are formed as recesses for exposing the lower end of the cylinder portion 21 of the fitting 20 to the outside. The three fitting receiving traces 16a, 16b are formed at the corners between the lower end 12a and the inner peripheral surface 12b of the elastic cylinder portion 12, spaced apart from each other in the circumferential direction. The fitting receiving trace 16a is provided on a virtual plane A including the axis C and the injection trace portion 15 and is formed symmetrically with respect to the virtual plane A. The two fitting receiving traces 16b are arranged symmetrically with respect to the virtual plane A.

[0032] Here, at an angle θ centered on the axis C, the position of the counter pole of the injection trace portion 15 with respect to the axis C is set to 0°. Also, in a bottom view, the angle θ increases clockwise and decreases counterclockwise from the 0° position. In this case, the fitting receiving trace 16a is arranged at the position where the angle θ is 180°, and the fitting receiving traces 16b are arranged at the positions where the angle θ is ±60°, respectively.

[0033] The lower end 12a of the elastic cylindrical portion 12 is formed such that the left half (within the range where the angle θ is -90° to 90°) is substantially perpendicular to the axis C, similar to the lower end of the cylindrical portion 21, and the right half is inclined upward as it goes rightward. Therefore, the fitting receiving trace 16a is located above the fitting receiving trace 16b.

[0034] The elastic flange portion 13 is a substantially annular plate-shaped member centered on the axis C, and the flange portion 22 is embedded therein. The upper surface 13a of the elastic flange portion 13 is formed in a planar shape perpendicular to the axis C. A groove 13c is formed at the right rear position on the lower surface 13b of the elastic flange portion 13. The lower surface 13b is inclined spirally downward as it moves counterclockwise from the groove 13c in a bottom view. The upper end of the coil spring contacts this lower surface 13b.

[0035] At the corner between the upper surface 13a of the elastic flange portion 13 and the inner peripheral surface 12b of the elastic cylindrical portion 12, four exposed recesses 18 are formed as recesses for exposing the corner between the cylindrical portion 21 and the flange portion 22 to the outside. The four exposed recesses 18 are arranged at equal intervals in the circumferential direction. Specifically, the four exposed recesses 18 are arranged at the positions where the angle θ is 0°, ±90°, and 180°, respectively.

[0036] On the outer peripheral surface 13d of the elastic flange portion 13, four circumferential groove portions 17 are formed that are recessed radially inward. The circumferential groove portions 17 are formed over the entire vertical length of the outer peripheral surface 13d. The four circumferential groove portions 17 are arranged at equal intervals in the circumferential direction. Specifically, the four circumferential groove portions 17 are arranged at the positions where the angle θ is ±45° and ±135°, respectively. The four installation recesses 26 are exposed to the outside by the four circumferential groove portions 17.

[0037] That is, in the fitting 20, four installation recesses 26 are respectively arranged at positions where the angle θ is ±45° and ±135°. Also, four through holes 24 are respectively arranged at the same positions. Four through holes 23 are respectively arranged at positions where the angle θ is 0°, ±90°, and 180°.

[0038] Next, with reference to FIG. 5 in addition to FIG. 4, a manufacturing method of the vibration isolator 10 will be described. FIG. 5 is a cross-sectional view of the vibration isolator 10 and the mold 30 taken along the line V-V of FIG. 1(b). The manufacturing method of the vibration isolator 10 mainly includes a holding step of holding the fitting 20 in the cavity of the mold 30, and a molding step of injecting a molding material of the elastic body from the injection port 34 into the cavity after the holding step to vulcanize and mold the vibration isolation base 11.

[0039] The mold 30 includes an upper mold 31 that molds the upper side of the vibration isolation base 11, and a lower mold 32 that molds the lower side of the vibration isolation base 11. When the upper mold 31 and the lower mold 32 are overlapped, the annular space formed between them is the cavity of the mold 30.

[0040] The parting line between the upper mold 31 and the lower mold 32 on the outer peripheral side of the vibration isolation base 11 is formed along the corner of the upper surface 13a and the outer peripheral surface 13d of the elastic flange portion 13. The parting line between the upper mold 31 and the lower mold 32 on the inner peripheral side of the vibration isolation base 11 is formed along the portion with the minimum inner diameter of the inner peripheral surface 12b of the elastic cylinder portion 12.

[0041] In the upper mold 31, the injection port 34 opens at a portion that molds the upper end of the mounting portion 14. Although not shown, a gate with a narrow passage cross-sectional area is formed at the tip of the injection port 34 (the boundary portion with the cavity). After the molding step, the elastic body is separated at this gate, so that the injection trace portion 15 is formed on the vibration isolation base 11. Thereby, even without checking the manufacturing method of the vibration isolator 10, by checking the manufactured vibration isolator 10, it can be known from the position of the injection trace portion 15 that the molding material of the elastic body was injected and the vibration isolation base 11 was molded.

[0042] In the molding process, the elastic molding material injected from the injection port 34 (the position of the injection trace portion 15) advances downward while being divided into both circumferential sides within the annular cavity. At this time, the air in the cavity pushed out by the molding material is discharged to the outside of the mold 30 through the gap between the upper mold 31 and the lower mold 32 or the like. Note that an air vent or the like for discharging this air may be formed at a predetermined position of the upper mold 31 or the lower mold 32.

[0043] The molding materials advancing from both circumferential sides often merge within the range where the angle θ shown in Fig. 1(b) is -10° to 10°. Before this merging, the molding materials bypass the edge of the fitting 20 or pass through a plurality of through holes 23, 24 formed in the fitting 20, and are filled on both sides of the fitting 20. If the advancing manner of this molding material is complicated or unstable, there is a possibility that molding defects such as burrs (depressions) may easily occur in the vibration-proof base 11 near the merging portion.

[0044] Since a plurality of through holes 23, 24 are formed in the fitting 20 side by side in the circumferential direction, the advancing manner of the molding material on both sides of the fitting 20 can be made to approach each other to the same extent. Thereby, it is possible to make it difficult for molding defects such as burrs to occur in the vibration-proof base 11.

[0045] Further, since the through holes 23, 24 are arranged at equal intervals in the circumferential direction respectively, the advancing manner of the molding material in the circumferential direction can be stabilized. Furthermore, since the through hole 23 of the cylindrical portion 21 and the through hole 24 of the flange portion 22 are arranged alternately and at equal intervals in the circumferential direction, the advancing manner of the molding material in the circumferential direction can be further stabilized. Since the through holes 23, 24 are arranged symmetrically with respect to the virtual plane A, the advancing manner of the molding material can be made uniform on both circumferential sides. As a result of these, it is possible to make it more difficult for molding defects such as burrs to occur in the vibration-proof base 11.

[0046] Since the molding material is injected from the injection port 34, the pressure (injection pressure) at the time of injecting the molding material tends to be high in the vicinity of the injection port 34. Therefore, if the through hole 24 is located in the flange portion 22 near the injection port 34, the flange portion 22 may be damaged starting from the through hole 24. However, in the present embodiment, since all the through holes 24 are located within the range of the angle θ of -170° to 170° and no through hole 24 is located near the injection port 34, it is possible to suppress the damage of the flange portion 22 starting from the through hole 24.

[0047] The upper mold 31 includes four upper convex portions 35a that respectively contact the upper surface of the installation recess 26 of the fitting 20 in a state where the fitting 20 is held in the holding step, and four auxiliary pressing portions 36 that respectively contact the corners of the cylindrical portion 21 and the flange portion 22 in the same state. Therefore, on the vibration isolation base body 11 after the molding step, as traces of the four upper convex portions 35a, four circumferential groove portions 17 above the installation recess 26 are respectively formed. Similarly, as traces of the auxiliary pressing portions 36, four exposed recess portions 18 are respectively formed. Therefore, even without checking the manufacturing method of the vibration isolation device 10, by checking the vibration isolation device 10 after manufacturing, it can be seen that the fitting 20 was in contact with the mold 30 at the positions of the circumferential groove portions 17 and the exposed recess portions 18 during its manufacturing.

[0048] When filling the cavity with the molding material in the molding step, since the fitting 20 is in contact with the upper mold 31 at the upper convex portion 35a (position of the circumferential groove portion 17) and the auxiliary pressing portion 36 (position of the exposed recess portion 18), it is possible to restrict the fitting 20 from floating upward. Since it is possible to suppress the variation in the advancing direction of the molding material according to this floating, it is possible to hardly cause molding defects such as burrs in the vibration isolation base body 11.

[0049] Since the upper convex portions 35a and the auxiliary pressing portions 36 are arranged at equal intervals in the circumferential direction, it is possible to suppress the axis C of the fitting 20 from tilting with respect to the axis C of the annular cavity. Further, since the upper convex portions 35a and the auxiliary pressing portions 36 are arranged alternately and at equal intervals in the circumferential direction, it is possible to make it more difficult for the fitting 20 to tilt within the cavity. As a result of these, since it is possible to stabilize the advancing direction of the molding material, it is possible to more hardly cause molding defects such as burrs in the vibration isolation base body 11.

[0050] The lower mold 32 includes a main body portion that molds the outer peripheral side of the vibration isolation base 11, and a movable portion 33 that molds the inner peripheral side of the vibration isolation base 11. A columnar insertion hole 32a centered on the axis C is formed through the main body portion. A part of the movable portion 33 is accommodated in the insertion hole 32a. During the molding process, air in the cavity is also discharged to the outside of the mold 30 through the gap between the main body portion and the movable portion 33.

[0051] The main body portion of the lower mold 32 includes four lower convex portions 35b that project radially inward with respect to the portion that molds the outer peripheral surface 13d of the elastic flange portion 13. At the upper end of the lower convex portion 35b, a step is formed on which the edge of the installation recess 26 is placed in a state where the fitting 20 is held during the holding process.

[0052] Therefore, on the vibration isolation base 11 after the molding process, four circumferential groove portions 17 are respectively formed below the upper surface of the installation recess 26 as traces of the four lower convex portions 35b. Therefore, even without checking the manufacturing method of the vibration isolation device 10, by checking the vibration isolation device 10 after manufacturing, it can be known that the fitting 20 contacted the mold 30 at the position of the circumferential groove portion 17 during its manufacturing.

[0053] When filling the cavity with a molding material during the molding process, the installation recess 26 is clamped vertically by the upper convex portion 35a and the lower convex portion 35b (at the position of the circumferential groove portion 17), so that the fitting 20 can be made difficult to tilt in the cavity. Furthermore, since the upper convex portion 35a and the lower convex portion 35b are arranged at equal intervals in the circumferential direction, the fitting 20 can be made even more difficult to tilt in the cavity. As a result, the advancing manner of the molding material can be stabilized, so that molding defects such as burrs are less likely to occur in the vibration isolation base 11.

[0054] The movable portion 33 is a substantially columnar portion centered on the axis C. The movable portion 33 is fixed to the tip of the rod of a telescopic cylinder 38 that expands and contracts along the axis C. In a state where the telescopic cylinder 38 is shortened to the maximum, the upper mold 31 and the lower mold 32 are overlapped, and a cavity corresponding to the shape of the vibration isolation base 11 is formed.

[0055] After the vibration-proof base 11 is molded, when the upper mold 31 and the lower mold 32 are split, the vibration-proof device 10 often remains attached to the lower mold 32. After splitting the mold, by extending the telescopic cylinder 38, the vibration-proof device 10 can be easily removed from the lower mold 32.

[0056] The movable part 33 includes three fitting-receiving parts 33a and 33b that project upward from the part that forms the lower end 12a of the elastic cylinder part 12. Further, these fitting-receiving parts 33a and 33b also project radially outward from the part that forms the inner peripheral surface 12b of the elastic cylinder part 12. The fitting-receiving part 33a is arranged at the position where the angle θ shown in Fig. 1(b) is 180°, and the fitting-receiving parts 33b are respectively arranged at the positions where the angle θ is ±60°.

[0057] The fitting-receiving parts 33a and 33b support the lower end of the cylinder part 21 from below. More specifically, the lower end of the cylinder part 21 is fitted into the step formed on the outer peripheral side edge of the upper end of the fitting-receiving parts 33a and 33b, so that the cylinder part 21 is supported by the fitting-receiving parts 33a and 33b.

[0058] Therefore, on the vibration-proof base 11 after the molding process, a fitting-receiving mark 16a is formed as a trace of the fitting-receiving part 33a, and a fitting-receiving mark 16b is formed as a trace of the fitting-receiving part 33b. Therefore, even without checking the manufacturing method of the vibration-proof device 10, by checking the vibration-proof device 10 after manufacturing, it can be known that the fitting 20 was supported by the mold 30 at the positions of the fitting-receiving marks 16a and 16b during its manufacturing.

[0059] As described above, when the molding material is filled into the cavity in the molding process, the molding materials that have advanced from both circumferential sides into the cavity are likely to merge within the range where the angle θ shown in Fig. 1(b) is -10° to 10°. If the fitting-receiving parts 33a and 33b are within this range, the flow of the molding material becomes complicated, and molding defects such as bare spots are likely to occur on the vibration-proof base 11.

[0060] However, in the present embodiment, since all the fitting-receiving parts 33a and 33b (fitting-receiving marks 16a and 16b) are located outside the range where the angle θ is -10° to 10°, the flow of the molding material at the time of merging in the molding process can be simplified, and it is possible to make it difficult for molding defects such as bare spots to occur on the vibration-proof base 11.

[0061] In particular, the fitting 20 has a cylindrical portion 21 extending in the axial direction (vertical direction) and a flange portion 22 extending in the radial direction, and has a more complex shape than the case where the fitting 20 is formed from either one of them. When such a fitting 20 having a complex shape is embedded in the vibration-proof base 11 having a similar shape in a molding process, the flow of the molding material is likely to become unstable, and there is a risk that molding defects are likely to occur in the vibration-proof base 11.

[0062] Also, in the molding process, the molding material is most likely to be finally filled in the vicinity of the lower end of the cylindrical portion 21 (the position of the lower end 12a of the elastic cylindrical portion 12) that is farthest from the injection port 34 in the vertical direction. Therefore, in the vicinity of the lower end of this cylindrical portion 21, there is a risk that molding defects are likely to occur due to the complication and instability of the flow of the molding material. However, even in a shape where such molding defects are likely to occur, since a plurality of fitting receiving portions 33a, 33b are not located at the position opposite to the injection port 34 with respect to the axis C, it is possible to sufficiently prevent molding defects from occurring during the molding of the vibration-proof base 11.

[0063] In the molding process, when there are four or more fitting receiving portions 33a, 33b that support the fitting 20, there is a risk that the annular fitting 20 may float from any one or more of them. On the other hand, in this embodiment, since there are three fitting receiving portions 33a, 33b (fitting receiving traces 16a, 16b), it is possible to make it difficult for the annular fitting 20 to float from each of the three fitting receiving portions 33a, 33b. Therefore, in the molding process, it is possible to suppress the flow of the molding material from becoming unstable due to the floating, and it is possible to make it more difficult for molding defects such as burrs to occur in the vibration-proof base 11.

[0064] Since the fitting receiving portions 33a, 33b (fitting receiving traces 16a, 16b) are arranged symmetrically with respect to the virtual plane A, it is possible to make the progress of the molding material in the molding process uniform on both sides in the circumferential direction. As a result, it is possible to stabilize the way in which these molding materials merge, and it is possible to make it more difficult for molding defects such as burrs to occur in the vibration-proof base 11.

[0065] The thickness (dimension in the vertical direction) of the elastic flange portion 13 is larger on the lower side than on the upper side with respect to the flange portion 22 of the metal fitting 20. In the molding process, the molding material is injected from the injection port 34 into the cavity above the flange portion 22. Therefore, in the molding process, the molding material is likely to be filled first in the cavity above the flange portion 22 and the cavity inside the cylindrical portion 21 connected thereto. Compared with this, the molding material is likely to be filled later in the cavity below the flange portion 22 and the cavity outside the cylindrical portion 21.

[0066] The metal fitting receiving portions 33a and 33b are provided in the cavity inside the cylindrical portion 21 where the molding material is likely to be filled first. Therefore, even if the flow pattern of the molding material becomes complicated around the metal fitting receiving portions 33a and 33b, the air etc. around them can be pushed out to the cavity outside the cylindrical portion 21 where the molding material is likely to be filled slowly. Thus, it is possible to make it less likely that molding defects such as burrs occur in the vibration isolation base 11.

[0067] The lower end of the cylindrical portion 21 and the lower end 12a of the elastic cylindrical portion 12 have the right half rising and inclined, and are not axisymmetric with respect to the axis C. However, since the lower end of the cylindrical portion 21 and the lower end 12a of the elastic cylindrical portion 12 are formed symmetrically with respect to the virtual plane A, even with such an inclination, the flow of the molding material in the vicinity of the lower end 12a in the molding process can be made uniform on both sides in the circumferential direction. As a result, in the vicinity of the lower end 12a where the metal fitting receiving traces 16a and 16b by the metal fitting receiving portions 33a and 33b are formed, the flow of the molding material can be stabilized, and it is possible to make it less likely that molding defects such as burrs occur in the vibration isolation base 11.

[0068] Next, the second embodiment will be described with reference to FIG. 6. In the first embodiment, the vibration isolation device 10 having four circumferential groove portions 17 and installation recesses 26 was described. In contrast, in the second embodiment, a vibration isolation device 40 having three circumferential groove portions 17 and installation recesses 26 will be described. For the parts that are the same as those in the first embodiment, the same reference numerals are given and the following description is omitted.

[0069] FIG. 6 is a bottom view of the vibration isolator 40 in the second embodiment. The vibration isolator 40 is configured identically to the vibration isolator 10 in the first embodiment, except that the number and arrangement of the circumferential groove portions 17 and the installation recessed portions 26 are different, and the mark recessed portion 25 is omitted. In FIG. 6, the illustration of the groove 13c is omitted.

[0070] In the vibration isolator 40, three circumferential groove portions 17 and three installation recessed portions 26 are arranged at equal intervals in the circumferential direction. Specifically, the three circumferential groove portions 17 and the three installation recessed portions 26 are respectively arranged at positions where the angle θ (see FIG. 1(b)) is 0°, ±120°.

[0071] Thus, when the fitting 20 is formed from a plate material by press forming or the like, if there are at least three installation recessed portions 26, it becomes easier to fix the plate material to the press forming die with the installation recessed portions 26, and it becomes easier to form the fitting 20.

[0072] Also, when manufacturing the vibration isolator 40, since three upper convex portions 35a corresponding to the three circumferential groove portions 17 are provided in the die 30, it becomes difficult for the annular fitting 20 to separate from each of the three upper convex portions 35a. As a result, it is possible to suppress the flow of the molding material from becoming unstable due to the separation, so that it is less likely to cause molding defects such as burrs on the vibration isolation base 11.

[0073] One of the three installation recessed portions 26 is at the same position as the through hole 23 or at the center position of the through hole 24 in the circumferential direction. Therefore, that one installation recessed portion 26 can be used as a mark instead of the mark recessed portion 25, and it becomes easier for the operator to recognize the orientation of the fitting 20 set in the die 30.

[0074] One of the circumferential groove portions 17 that exposes the metal fitting 20 to the outside is located within the range where the angle θ is from -10° to 10°. However, the circumferential groove portion 17 is formed on the outer peripheral surface 13d of the vibration-proof base 11 and is not formed on the lower end side of the vibration-proof base 11. Similarly, one of the upper convex portion 35a and the lower convex portion 35b corresponding to the circumferential groove portion 17 is located within the range where the angle θ is from -10° to 10°, but does not support the lower end side of the metal fitting 20 from below. Therefore, in the molding process, even if the upper convex portion 35a and the lower convex portion 35b are located within the range where the angle θ is from -10° to 10°, the molding material that has merged in the vicinity thereof flows further downward, so it is difficult for molding defects such as burrs to occur in the vibration-proof base 11.

[0075] As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments at all, and it can be easily inferred that various improvements and modifications are possible without departing from the spirit of the present invention. For example, the number and arrangement of the through holes 23, 24, the metal fitting receiving traces 16a, 16b (metal fitting receiving portions 33a, 33b), the circumferential groove portion 17 (upper convex portion 35a, lower convex portion 35b), the installation recess 26, the exposure recess 18 (auxiliary pressing portion 36), etc. may be appropriately changed.

[0076] In the above embodiment, the vibration-proof device 10 in which the metal fitting 20 having the cylindrical portion 21 and the flange portion 22 is embedded in the vibration-proof base 11 having the same shape has been described. However, it is not necessarily limited to this. The metal fitting may be an annular member surrounding the axis C. For example, it may be formed only by the cylindrical portion 21 or only by the flange portion 22. Further, the annular member is not limited to a circular shape, and may be a polygonal shape, an elliptical shape, an oval shape, or the like. Similar to such an annular metal fitting, the vibration-proof base may be an annular member in which the annular metal fitting is embedded over the entire circumference. If the metal fitting and the vibration-proof base are annular, the vibration-proof device 10 constituted by them may be various vibration-proof devices other than the spring seat trapper.

[0077] In the above-described embodiment, the case where all the fitting receiving portions 33a and 33b (fitting receiving traces 16a and 16b) are located outside the range of -10° to 10° of the angle θ has been described, but it is not necessarily limited to this. For example, all the fitting receiving portions 33a and 33b (fitting receiving traces 16a and 16b) may be located outside the range of -50° to 50° of the angle θ. More specifically, the fitting receiving portion 33b (fitting receiving trace 16b) may be provided at positions where the angle θ is 50° to 70° or -50° to -70°, and the fitting receiving portion 33a (fitting receiving trace 16a) may be provided at positions where the angle θ is 170° to 180° or -170° to -180°. In this case, while ensuring the intervals between the three fitting receiving portions 33a and 33b (fitting receiving traces 16a and 16b), the symmetry with respect to the virtual plane A can be ensured. As a result, the flow pattern of the molding material in the molding process can be stabilized, and it is possible to make it difficult for molding defects such as burrs to occur in the vibration isolation base 11.

[0078] In the above-described embodiment, the thickness (dimension in the vertical direction) of the elastic flange portion 13 of the vibration isolation base 11 increases counterclockwise from the groove 13c in the bottom view shown in FIG. 1(b) due to the planar upper surface 13a and the spiral lower surface 13b. Note that this groove 13c is located at a position where the angle θ is approximately -70°.

[0079] Therefore, the cavity of the portion for molding the elastic flange portion 13 becomes wider counterclockwise from the position of approximately -70° in the bottom view in the vertical direction. Therefore, when the molding material advances from the injection port 34 to both sides in the circumferential direction within the cavity, the front half (range of 0° to 180°) with respect to the virtual plane A may be more easily filled with the molding material first.

[0080] Therefore, the molding materials advancing from both sides in the circumferential direction may easily merge within the range where the angle θ is -20° to 0°. Thus, the vibration isolation device 10 and its manufacturing method may be configured such that all the fitting receiving portions 33a and 33b (fitting receiving traces 16a and 16b) are provided outside the range of -20° to 0° of the angle θ. Thereby, the flow pattern of the molding material at the time of merging in the molding process can be further simplified, and it may be possible to make it difficult for molding defects such as burrs to occur in the vibration isolation base 11.

Explanation of Reference Numerals

[0081] 10,40 Vibration isolation device 11 Vibration isolation base 12 Elastic cylinder part 13 Elastic flange part 15 Injection trace part 16a, 16b Fitting receiving trace 20 Fitting 21 Cylinder part 22 Flange part 23, 24 Through hole 30 Mold 31 Upper mold 32 Lower mold 33a, 33b Fitting receiving part 34 Injection port C Axis center θ Angle

Claims

1. An annular vibration isolation base body made of an elastic body, and an annular fitting embedded throughout the circumference inside the vibration isolation base body, wherein the vibration isolation base body includes an injection trace portion of an elastic body formed on one end side in the axial direction, and a plurality of fitting receiving traces formed on the other end side in the axial direction, separated from each other in the circumferential direction and exposing the fitting to the outside, and when the position of the antipole of the injection trace portion with respect to the axis is set to 0° at an angle centered on the axis of the fitting, a plurality of the fitting receiving traces are located outside the range of -10° to 10°, a vibration isolation device characterized by this.

2. The vibration isolation device according to claim 1, wherein the number of the fitting receiving traces formed on the other end side in the axial direction of the vibration isolation base body is three.

3. The vibration isolation device according to claim 1, wherein the fitting receiving traces formed on the other end side in the axial direction of the vibration isolation base body are symmetrically arranged with respect to a virtual plane including the axis and the injection trace portion.

4. The fitting includes a cylindrical tube portion surrounding the axis, and an annular flange portion extending radially outward from an end portion on one end side in the axial direction of the tube portion, and the vibration isolation base body includes a cylindrical elastic tube portion in which the tube portion is embedded, and an elastic flange portion extending radially outward from an end portion on one end side in the axial direction of the elastic tube portion and in which the flange portion is embedded, and a plurality of the fitting receiving traces are formed in the elastic tube portion so that an end portion on the other end side in the axial direction of the tube portion is exposed, the vibration isolation device according to any one of claims 1 to 3.

5. A plurality of through holes are formed through the flange portion in the axial direction, and when the position of the antipole of the injection trace portion with respect to the axis is set to 0° at an angle centered on the axis, a plurality of the through holes are located within the range of -170° to 170°, the vibration isolation device according to claim 4.

6. A method for manufacturing a vibration isolation device including an annular vibration isolation base body made of an elastic body and an annular fitting embedded throughout the circumference inside the vibration isolation base body, the method comprising: a holding step of holding the fitting in a mold, and a molding step of injecting a molding material of an elastic body from an injection port into the mold after the holding step to vulcanize and mold the vibration isolation base body, wherein the mold includes an upper mold having the injection port and molding one end side in the axial direction of the vibration isolation base body, and a lower mold having a plurality of fitting receiving portions that support the other end side in the axial direction of the fitting and are separated from each other in the circumferential direction, and molding the other end side in the axial direction of the vibration isolation base body. A method for manufacturing a vibration isolator, characterized in that, at an angle centered on the axis of the fitting, when the position of the antipole of the injection port with respect to the axis is set to 0°, a plurality of the fitting receiving portions are located outside the range of -10° to 10°.

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