JP3873196B1 - Anti-vibration device manufacturing method - Google Patents

Abstract

It is possible to discharge air in the vicinity of the upper end portion of a cylindrical core, and to prevent the occurrence of end surface burrs while eliminating the problem of die cutting after molding.
In an annular hole 40 into which an upper end portion 12A of a cylindrical core body 12 is fitted, a seal ring 62 is provided on an inner peripheral portion of a nested mold 44, and an inner diameter D1 of the seal ring is set outside the cylindrical core body. The seal ring 62 is set to be larger than the diameter D2 and is provided with a large-diameter portion 62B projecting in the radial direction at the upper end to sandwich the large-diameter portion in the axial direction, and a clearance 66 is provided on the outer periphery of the lower end portion 62A. The molding material 20 is injected from the injection hole 39 into the cavity 38 using the molding die 30 that is configured to be displaceable so that the lower end 62A side is inclined with respect to the axial direction Z with the large-diameter portion 62B as a fulcrum. The cylindrical core body 12 is pressed by the molding material so as to be displaced so that the seal ring 62 is inclined, whereby an elliptical seal line 70 having a height difference H in the axial direction Z is formed.
[Selection] Figure 3

Description

  The present invention relates to a method of manufacturing a cylindrical vibration isolator used mainly as a vibration isolating rubber bush or an anti-vibration mount for a vehicle.

  As an anti-vibration rubber bush or anti-vibration mount for a vehicle, a rubber core is interposed between a cylindrical core body as an inner cylinder and an outer cylinder member, or a cylindrical core body without an outer cylinder member There is known a rubber elastic body integrally formed on the outer periphery of the rubber.

  As a molding die for molding such a cylindrical vibration isolator, generally, the axial side surface of the rubber elastic body is molded opposite to each other in both upper and lower cavity components that can be closed. A nesting die is arranged, and at least one nesting die of both the upper and lower die types, for example, a guide pin is provided at the center portion of both nesting die, the end of the cylindrical core is fitted to the guide pin, and both ends are In a state where the upper and lower molds are closed while being locked and supported in an upright state, a cavity is formed around the cylindrical core body, and a molding material of a rubber elastic body is injected and filled into the cavity from an injection hole (See, for example, Patent Document 1 below).

  By the way, the portion of the cylindrical core body supported as described above that protrudes upward and downward from the cavity is inserted into an annular hole portion at the center of the upper and lower nesting molds, but the molding material injected into the cavity is In some cases, it passes through the gap between the end portion of the cylindrical core body and the annular hole portion on the outer periphery thereof, reaches the end surface of the cylindrical core body and becomes an end surface burr. When such end surface burrs are generated, the removal work is required, and there is a problem that the production efficiency is reduced due to an increase in the number of man-hours. If this is the case, the man-hours for deburring work are large.

  Therefore, for example, in Patent Document 2 below, a seal ring including a distal end portion fitted to the end portion of the cylindrical core body is provided in an annular hole portion into which the end portion of the cylindrical core body is fitted, and the seal ring Thus, a technique for blocking the leakage of the molding material has been proposed. In addition, it is described that the seal ring has a cylindrical shape including a large-diameter portion projecting outward at the upper end portion, and a gap is provided on the outer periphery of the tip portion (see paragraph 0009 and FIG. 1).

  However, in the technique of Patent Document 2, the seal ring has a dimension in which the inner diameter of the tip part is in close contact with the outer periphery of the cylindrical core body, and the tip part of the seal ring is elastically expanded and deformed as the mold is closed. The outer periphery of the distal end portion of the cylindrical core body is tightly fitted (see paragraph 0007 and the like), and the clearance at the outer periphery of the distal end portion is merely a clearance for elastic expansion deformation (paragraph 0009 and the like). reference). As described above, in the technique of Patent Document 2, since the outer peripheral surface of the end portion of the cylindrical core body is tightly fitted with the seal ring, that is, the structure is tightly fitted, the occurrence of end surface burrs can be eliminated. However, it does not easily come off during die cutting after molding, which impairs workability. In addition, if the airtight state is maintained, the air in the cavity may not be completely discharged. Especially when the air remains in the vicinity of the upper end of the cavity, the mark remains on the molded product, resulting in defective molding. Causes it to occur.

  On the other hand, the following Patent Document 3 describes that a ring ring into which an end portion of a cylindrical core body is fitted is provided with a seal ring having a tip portion that is externally fitted to the end portion of the cylindrical core body. The seal ring has a slightly larger inner diameter of the seal ring than the outer diameter of the cylindrical core so that the seal ring is fitted to the outer periphery of the upper end of the cylindrical core while maintaining a slight air permeability. The point to do is described.

However, in the technique of Patent Document 3, the seal ring is accommodated in a recessed portion formed in a nested shape without a gap, and displacement is not allowed. Therefore, although this seal ring can discharge the air in the cavity, this alone cannot prevent the generation of end surface burrs. Therefore, in Patent Document 3, the air in the cavity and the surplus molding material are removed. Generation of burr on the end face is prevented by providing a relief hole for discharging.
Japanese Utility Model Publication No. 5-28020 JP 7-276382 A Japanese Patent Laid-Open No. 2002-079551

  The present invention has been made in view of the above points, and enables generation of air in the vicinity of the upper end portion of the cylindrical core body, and generation of end face burrs while eliminating the problem of die cutting after molding. It is an object of the present invention to provide a method for manufacturing a vibration isolator capable of preventing the occurrence of vibration.

  The present invention is a method of manufacturing a vibration isolator formed by integrally molding a rubber elastic body on the outer periphery of a cylindrical core body, and is characterized by using a molding die having the following configuration.

  That is, the molding die includes an upper die and a lower die that can be directly or intermediately sandwiched between the upper die and the lower die, and the upper die and the lower die each include an annular hole portion into which an end portion of the cylindrical core body is fitted. In the state where the upper mold and the lower mold are closed, a cavity for forming the rubber elastic body is formed on the outer periphery of the cylindrical core body in which both end portions are fitted into the upper and lower annular holes, and the cavity A mold provided with an injection hole for injecting a molding material from one place in the circumferential direction, the upper mold is an annular nesting mold that molds the axial side surface of the rubber elastic body, A core body presser disposed in an axially displaceable manner in the inner peripheral portion of the telescopic mold and biased downward by a biasing means, and a lower surface of the core body presser projecting from the bottom surface of the cylindrical core body And a guide pin that guides the cylindrical core body by being inserted from the upper end opening, The annular hole portion on the side is formed by the inner peripheral surface of the nested mold, the outer peripheral surface of the guide pin, and the lower surface of the core body pressing member, and an accommodation recess is provided on the inner peripheral surface of the nested mold, A seal ring having a lower end portion fitted in the upper annular hole portion with respect to the upper end portion of the core body is disposed in the housing recess, and the seal ring has a cylindrical shape whose inner diameter is constant in the axial direction; The inner diameter is set to be larger than the outer diameter of the cylindrical core body, and the upper end portion is formed as a large-diameter portion projecting in the radial direction, and the large-diameter portion is formed in the stepped portion provided in the accommodating recess. It is arranged and clamped in the axial direction, and a clearance is provided on the outer periphery of the lower end portion, so that the lower end side can be displaced so that it tilts with respect to the axial direction with the portion where the large diameter portion is clamped as a fulcrum It is configured.

  The above manufacturing method uses the molding die to form a cylindrical core body whose outer peripheral surface of the end portion is chamfered in a tapered shape, and a state in which the end portion having the chamfered portion is fitted into the upper annular hole portion. A mold closing step in which the upper mold and the lower mold are closed by placing in the mold, and a cavity is formed on the outer periphery of the cylindrical core, and a molding material is injected into the cavity from the injection hole It includes a molding step of filling and molding the rubber elastic body and a demolding step of opening the upper mold and the lower mold after molding to remove the molded vibration isolator.

  In the molding step, the cylindrical core body is pressed by the molding material injected into the cavity from the injection hole, and the upper end portion of the cylindrical core body is directed to the side opposite to the injection hole by the pressing. The lower end portion of the seal ring is displaced by the displacement so that the lower end portion of the seal ring is inclined with the large-diameter portion as a fulcrum. An elliptical seal line having a height difference in the direction is formed, and the elliptical seal line is such that the lower end corner of the seal ring on the injection hole side contacts the outer peripheral surface of the upper end portion of the cylindrical core body. The lower seal part formed by the above and the upper part formed by the obtuse angle part at the lower end of the chamfered part of the cylindrical core body contacting the inner peripheral surface of the seal ring opposite to the injection hole And a lower seal. In the portion, the leakage of the molding material at the initial stage of filling is cut off, and then loosened as compared with the lower seal portion as the molding material is filled so as to go around the outer periphery of the cylindrical core. While the air in the cavity is released from the upper seal portion to be sealed, the leakage of the molding material in the upper seal portion is finally blocked.

  According to the present invention, the seal ring that is externally fitted to the upper end portion of the cylindrical core body is set to have an inner diameter larger than the outer diameter of the cylindrical core body, and the large diameter portion of the upper end portion is sandwiched in the axial direction. In addition, since a gap is provided on the outer periphery of the lower end portion that is fitted around the cylindrical core body, when the cylindrical core body is pressed and displaced by the injected molding material in the molding process, the displacement Following this, the seal ring is displaced so as to be inclined with respect to the axial direction with the large diameter portion as a fulcrum. As a result, the elliptical seal line having a difference in height in the axial direction is formed between the cylindrical core and the seal ring, so that the molding material leaks at the initial stage of filling in the lower seal portion to be tightly sealed. After that, the air in the cavity is released from the upper seal portion at the chamfered portion that loosely seals, and finally, leakage of the molding material at the upper seal portion can be blocked. Further, since the inner diameter of the seal ring is larger than the outer diameter of the cylindrical core body, it is possible to solve the die-cutting problem that the vibration isolator formed in the demolding process is difficult to come off from the upper mold.

  Next, embodiments of the present invention will be described based on examples shown in the drawings. FIG. 1 is a longitudinal sectional view of a vibration isolator 10 according to an embodiment, and FIG. 2 is a longitudinal sectional view of a molding die 30 for molding the vibration isolator 10.

  The vibration isolator 10 includes a cylindrical core body 12 as an inner cylinder, an outer cylindrical member 14 that coaxially surrounds the cylindrical core body 12, and a rubber that is interposed between the cylindrical core body 12 and the outer cylindrical member 14 to couple them together. The rubber elastic body 16 is vulcanized and bonded to both the cylindrical core body 12 and the outer cylindrical member 14. The cylindrical core body 12 is longer than the outer cylinder member 14, and both end portions 12 </ b> A and 12 </ b> B protrude from the axial side surface 16 </ b> A of the rubber elastic body 16.

  Both end portions 12A and 12B of the cylindrical core body 12 are provided with a chamfered portion 18 by chamfering the outer peripheral surface into a tapered shape. In addition, although not shown in figure, the sawtooth-shaped groove | channel by knurling is formed in the both end surfaces 12C and 12D of the cylindrical core body 12. FIG.

  The molding die 30 includes an upper die 34 and a lower die 36 which are closed with an intermediate die 32 interposed therebetween, and the outer periphery of the cylindrical core body 12 supported in an upright posture in the die by closing the die. In addition, a cavity 38 for molding the rubber elastic body 16 is formed. The upper die 34 is provided with an injection hole 39 for injecting the molding material 20 (see FIG. 7) of the rubber elastic body 16 from one place in the circumferential direction with respect to the cavity 38.

  The upper die 34 and the lower die 36 are provided with upper and lower annular holes 40 and 42 into which the end portions 12A and 12B of the cylindrical core body 12 are respectively inserted in order to support the cylindrical core body 12 in an upright posture. It has been.

  The molding die 30 is provided with annular nesting dies 44 and 46 for molding the axial side surface 16A of the rubber elastic body 16 so as to face each other in the vertical direction. The insert molds 44 and 46 are fitted into recesses 34A and 36A provided in the upper mold 34 and the lower mold 36, respectively, and are fixed with bolts (not shown) or the like. The annular holes 40 and 42 are provided at the center of the nesting dies 44 and 46, and these are formed continuously from the molding surface portions of the nesting dies 44 and 46 for molding the axial side surface 16A. .

  The annular hole 42 on the lower mold 36 side is provided with a support pin 48 that protrudes in an upright manner so as to be inserted into the cylindrical core body 12 from the lower end opening and locked at the lower end at the center thereof. . A locking step portion 50A for locking the end surface 12D of the cylindrical core body 12 is formed on the base portion 50 of the support pin 48, and a ring-shaped member 52 is fitted on the outer periphery thereof. The support pin 48 is configured to be able to be pushed upward and moved by an eject pin provided continuously downward at the time of mold release after molding.

  The annular hole 40 on the upper mold 34 side is provided with a core holding member 54 that is concentric with the support pin 48 and faces the upper and lower sides to lock the upper end of the cylindrical core body 12. As shown in FIG. 3, the upper part of the core body presser 54 is disposed in a recessed portion 34 </ b> B provided in the upper die 34, and is provided so as to be slidable in the axial direction Z at the inner peripheral portion of the upper nested die 44. It is biased downward by a spring 56 which is a biasing means provided at the top.

  The core body presser 54 is guided by an inner peripheral surface of a seal ring 62 described later and is provided so as to be displaceable in the axial direction, and is configured to be able to follow the displacement of the seal ring 62. Therefore, the outer diameter of the core body retainer 54 is set smaller than the diameter of the recessed portion 34B, and a clearance is ensured between the inner peripheral surface of the recessed portion 34B.

  As shown in FIG. 3, a guide pin 58 that guides the cylindrical core body 12 by projecting downward from the upper end opening of the cylindrical core body 12 on the lower surface 54 </ b> A of the core body presser 54. The lower surface of the core pressing member 54 around the guide pin 58 is formed as a locking step portion for locking the upper end surface 12C of the cylindrical core body 12. The upper annular hole 40 is formed by the inner peripheral surface of the insert mold 44, the outer peripheral surface of the guide pin 58, and the lower surface of the core body retainer 54 (particularly, the locking step portion).

  The upper insert mold 44 is provided with an accommodation recess 60 on its inner peripheral surface, and a seal ring 62 made of carbon steel, spring steel or the like is accommodated in the accommodation recess 60. The seal ring 62 has a cylindrical shape whose inner diameter D1 is constant in the axial direction, and a lower end portion 62A that fits outside the upper end portion 12A of the cylindrical core body 12 in the upper annular hole portion 40, and an upper end portion And a large-diameter portion 62B projecting in a radial direction from the lower end portion 62A.

  The inner diameter D1 of the seal ring 62 is set larger than the outer diameter D2 of the cylindrical core body 12. The difference in diameter between the two is not particularly limited as long as an elliptical seal line 70 described later is formed, but is preferably 0.02 to 0.10 mm. As an example, the inner diameter D1 of the seal ring 62 is 21.04 mm while the outer diameter D2 of the cylindrical core body 12 is 21 mm.

  As shown in FIG. 4, a stepped portion 64 is formed in the upper end portion of the accommodating recess 60 by being deeply depressed, and the large diameter portion 62B of the seal ring 62 is disposed on the stepped portion 64, The large-diameter portion 62B is sandwiched in the axial direction Z between the lower surface of the upper die 34. The diameter of the housing recess 60 is set so that a gap 66 is provided on the outer periphery of the seal ring 62 including the lower end 62A. The gap 66 is preferably 0.15 mm or more, and more preferably 0.3 mm or more in a state where the seal ring 62 is disposed concentrically with the housing recess 60.

  In this way, the inner diameter D1 of the seal ring 62 is made larger than the outer diameter D2 of the cylindrical core body 12, and the large-diameter portion 62B at the upper end is sandwiched in the axial direction and is fitted to the cylindrical core body 12 Since the clearance 66 is provided on the outer periphery of the lower end 62A, the lower end 62A has a degree of freedom in radial displacement, so that the cylindrical core 12 is inclined as shown in an enlarged view in FIG. Then, following the displacement, the seal ring 62 may swing and displace so that the lower end 62A side is inclined with respect to the axial direction Z with the portion where the large diameter portion 62B is sandwiched as a fulcrum. it can.

  In order to allow displacement of the cylindrical core body 12 and the seal ring 62 within a predetermined range, the cylindrical core body 12 is provided between the inner peripheral surface of the cylindrical core body 12 and the outer peripheral surface of the guide pin 58, and the cylindrical core. Clearances are provided between the outer peripheral surface of the body 12 and the inner peripheral surface of the nested mold 44 (inner peripheral surface below the seal ring 62). Further, the inner diameter D1 of the seal ring 62 is set smaller than the inner diameter of the nested mold 44.

  In the above description, the seal ring 62 disposed in the annular hole 40 on the upper die 34 side has been described. In the present embodiment, the seal ring 68 is similarly disposed in the annular hole 42 on the lower die 36 side. Yes.

  Next, a method for forming the vibration isolator 10 using the mold 30 will be described.

(1) First, the cylindrical core body 12 and the outer cylinder member 14 are set in a state where the upper mold 34 and the lower mold 36 are opened. At that time, the cylindrical core body 12 is fitted into the support pin 48 of the lower mold 36, and the lower end portion 12B is fitted into the annular hole portion 42 to be supported in an upright state. Further, the outer cylinder member 14 is fitted and set to the fitting step portion 47 on the outer peripheral portion of the insert mold 46.

Then, when the upper die 34 and the lower die 36 are closed, a cavity 38 is formed on the outer periphery of the cylindrical core body 12 as shown in FIG. 2, and as shown in FIG. The upper end portion 12 </ b> A having the chamfered portion 18 is disposed in a state of being fitted into the upper annular hole portion 40, and the upper end portion 12 </ b> A is in a state of being externally fitted by the lower end portion 62 </ b> A of the seal ring 62.

(2) Next, the rubber elastic body 16 is molded by injecting and filling the molding material 20 into the cavity 38 from the injection hole 39 provided in the upper die 34 (see FIG. 7).

  At that time, the molding material 20 injected from the injection hole 39 is filled from the injection hole 39 side in the circumferential direction of the cavity 38, so that the cylindrical core body 12 is injected from the injection hole 39 side by the molding material 20. In other words, the right side in FIG. 3 is the pressing side, and the left side of the opposite side (the side opposite to each other by 180 ° across the shaft) is the opposite pressing side. Due to this pressing, the cylindrical core body 12 is displaced in the upper end portion 12A toward the side opposite to the injection hole 39 (that is, the side opposite to the pressing side) within a predetermined clearance range. When the lower end portion 62A is pushed, the seal ring 62 is tilted and displaced so that the lower end portion 62A is inclined with respect to the axial direction Z with the large diameter portion 62B as a fulcrum as shown in FIG. At that time, the core body presser 54 arranged inside the seal ring 62 is configured to be able to follow the movement of the seal ring 62 by being guided only by the seal ring 62. The seal ring 62 is displaced without being obstructed.

  Thereby, as shown in FIGS. 5 and 6, an elliptical seal line 70 having a height difference H in the axial direction Z is formed between the outer peripheral surface of the upper end portion 12 </ b> A of the cylindrical core body 12 and the seal ring 62. The More specifically, on the pressing side (injection hole 39 side), the corner 62C at the lower end of the pressing side of the seal ring 62 is pressed against the outer peripheral surface of the upper end 12A of the cylindrical core body 12 to form an elliptical shape. This is the lower seal portion 72 in the seal line 70. The lower seal portion 72 is formed with high accuracy by the seal ring 62 itself and has hardness due to quenching or the like, and the right-angle corner portion 62C is pressed against the outer peripheral surface of the cylindrical core body 12, High sealing performance is demonstrated.

  Further, on the side opposite to the pressing side (the side opposite to the injection hole 39), the obtuse angle portion 18 </ b> A at the lower end of the chamfered portion 18 of the cylindrical core body 12 abuts on the inner peripheral surface of the seal ring 62. It becomes the upper seal portion 74 in the seal line 70. The upper seal portion 74 is formed by merely cutting the chamfered portion 18 of the cylindrical core body 12, so that the molding accuracy is low and the obtuse angle portion 18 </ b> A contacts the inner peripheral surface of the seal ring 62. By contacting, the sealing performance is lower than that of the lower seal portion 72, that is, it seals loosely.

  The height difference H between the lower seal portion 72 and the upper seal portion 74 is the case of the above specific example (the cylindrical core outer diameter D2 = 21 mm and the seal ring inner diameter D1 = 21.04 mm). H = 1.6 mm.

  The oval seal line 70 prevents leakage of the molding material 20 from the beginning of filling by the lower seal portion 72 that tightly seals on the pressing side, thereby preventing the occurrence of end surface burrs. Thereafter, the molding material 20 is filled in the cavity 38 so as to go around the outer periphery of the cylindrical core body 12. At this time, the molding material 20 starts from the upper seal portion 74 that seals more loosely than the lower seal portion 72. The air in the cavity 38 can be released little by little. Finally, while the air in the cavity 38 in the vicinity of the upper end of the cylindrical core 12 escapes from the upper seal portion 74, the upper seal portion 74 has a gap that allows the molding material 20 to leak. Since it is not a part, the leakage of the molding material 20 can be blocked.

(3) After molding in this way, the upper mold 34 and the lower mold 36 are opened and the molded vibration isolator 10 is taken out. At this time, since the inner diameter D1 of the seal ring 62 is larger than the outer diameter D2 of the cylindrical core body 12, there is no problem of die removal that sticks to the upper die 34 and is difficult to come off.

  According to the present embodiment described above, the seal by the seal ring 62 is configured as an elliptical seal line 70 having a height difference, so that air in the cavity 38 in the vicinity of the upper end portion of the cylindrical core body 12 is released, Generation | occurrence | production of the burr | flash in the end surface 12C of the cylindrical core body 12 can be prevented. In particular, the tapered chamfered portion 18 is provided on the upper end portion 12A of the cylindrical core body 12 fitted by the seal ring 62, and the elliptical seal line 70 is configured. Air from the upper seal portion 74 can be easily discharged, and air accumulation can be effectively prevented.

  In addition, since the seal ring 62 is not configured to be tightly fitted to the outer periphery of the cylindrical core body 12, it is possible to eliminate the die-cutting problem that the vibration isolator 10 molded in the demolding process is difficult to come off from the upper mold 34. it can.

  In particular, when the seal shape is circular rather than elliptical as in the past, trying to eliminate end surface burrs will cause problems with air accumulation and die removal, and conversely, eliminate problems with air accumulation and die removal. Then, there is a trade-off problem that end surface burrs are generated. However, the configuration of the above embodiment can solve this problem at low cost.

It is a longitudinal cross-sectional view of the vibration isolator which concerns on embodiment. It is a longitudinal cross-sectional view of the shaping | molding die for shape | molding the vibration isolator. It is a principal part expanded sectional view of the same shaping | molding die. It is sectional drawing of the annular hole part of the upper mold | type before shaping | molding of the same shaping | molding die. It is sectional drawing of the annular hole part of the upper mold | type in the middle of shaping | molding of the same shaping | molding die. It is a perspective view which shows typically the seal structure of the same shaping | molding die. It is a longitudinal cross-sectional view after shaping | molding of the same shaping | molding die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vibration isolator, 12 ... Cylindrical core, 12A ... Upper end part, 12B ... Lower end part,
14 ... outer cylinder member, 16 ... rubber elastic body, 16A ... axial side surface,
18 ... chamfered portion, 18A ... obtuse angle portion at the lower end, 20 ... molding material,
30 ... Mold, 32 ... Intermediate mold, 34 ... Upper mold, 36 ... Lower mold,
38 ... cavity, 39 ... injection hole 40 ... upper annular hole, 42 ... lower annular hole, 44 ... nested die 54 ... core body presser, 54A ... lower surface, 56 ... spring (biasing means),
58 ... guide pins, 60 ... receiving recesses,
62 ... Seal ring, 62A ... Lower end portion, 62B ... Large diameter portion, 62C ... Lower end corner portion 64 ... Step portion, 66 ... Gap, 70 ... Elliptical seal wire,
72 ... lower seal part, 74 ... upper seal part,
Z ... axial direction, D1 ... inner diameter of seal ring, D2 ... outer diameter of cylindrical core, H ... height difference

Claims (2)

A method of manufacturing a vibration isolator (10) formed by integrally molding a rubber elastic body (16) on the outer periphery of a cylindrical core body (12),
An upper mold (34) and a lower mold (36) that can be closed directly or with an intermediate mold interposed therebetween are provided, and the upper mold and the lower mold are annular in which end portions (12A, 12B) of the cylindrical core body are fitted. The rubber elastic body is formed on the outer periphery of the cylindrical core body having holes (40, 42) and having both ends fitted into the upper and lower annular hole portions in a state where the upper mold and the lower mold are closed. A mold (30) in which a cavity (38) is formed and an injection hole (39) for injecting a molding material from one place in the circumferential direction is provided to the cavity,
The upper die (34) is disposed so as to be displaceable in the axial direction (Z) at an annular nesting die (44) for molding the axial side surface (16A) of the rubber elastic body and an inner peripheral portion of the nesting die. A core body presser (54) biased downward by the biasing means (56) and a lower surface (54A) of the core body presser so as to be inserted into the cylindrical core body from the upper end opening. A guide pin (58) for guiding the cylindrical core body, and the upper annular hole (40) includes an inner peripheral surface of the nesting mold, an outer peripheral surface of the guide pin, and the core body pressing member. Formed by the lower surface,
An accommodation recess (60) is provided on the inner peripheral surface of the nesting type, and a seal ring (62) provided with a lower end (62A) that fits into the upper end of the cylindrical core in the upper annular hole. Arranged in the receiving recess,
The seal ring has a cylindrical shape whose inner diameter (D1) is constant in the axial direction, the inner diameter is set larger than the outer diameter (D2) of the cylindrical core body, and the upper end portion projects radially. The large-diameter portion (62B) is formed, and the large-diameter portion is disposed on the step portion (64) provided in the receiving recess and is sandwiched in the axial direction, and on the outer periphery of the lower end portion (62A). By using the molding die (30) configured to be displaceable so that the lower end side is inclined with respect to the axial direction with a portion where the large-diameter portion is sandwiched as a fulcrum by providing the gap (66),
The cylindrical core body (12) whose outer peripheral surface of the end portion is chamfered in a tapered shape, and the end portion (12A) having the chamfered portion (18) is fitted in the upper annular hole portion (40); A mold closing step in which the upper mold (34) and the lower mold (36) are closed on the mold (30), and a cavity (38) is formed on the outer periphery of the cylindrical core body; ,
A molding step of injecting and filling the molding material (20) into the cavity from the injection hole (39) to mold the rubber elastic body (16);
Removing the anti-vibration device (10) formed by opening the upper mold and the lower mold after molding,
In the molding step, the cylindrical core body (12) is pressed by the molding material (20) injected into the cavity from the injection hole, and the upper end (12A) of the cylindrical core body is injected by the pressing. Displacement is made toward the opposite side of the hole, and the displacement causes the lower end (62A) of the seal ring (62) to be inclined with the large diameter portion (62B) as a fulcrum. An elliptical seal line (70) having an axial height difference (H) between the seal ring and the seal ring is formed on the outer peripheral surface of the upper end portion of the body. The lower seal portion (72) formed by the lower end corner portion (62C) on the injection hole side coming into contact with the outer peripheral surface of the upper end portion of the cylindrical core body is opposite to the injection hole of the seal ring. The lower end of the chamfered portion of the cylindrical core on the inner peripheral surface An obtuse angle part (18A) is formed by contacting the upper seal part (74), and in the lower seal part (72), the leakage of the molding material in the initial stage of filling is blocked, As the molding material is filled so as to wrap around the outer periphery of the cylindrical core, the air in the cavity from the upper seal portion (74) that seals more loosely than the lower seal portion. Finally, the leakage of the molding material in the upper seal portion is blocked while letting go. The core body presser (54) is guided by the inner peripheral surface of the seal ring (62) and provided so as to be displaceable in the axial direction, and is configured to be able to follow the displacement of the seal ring. A method for manufacturing a vibration isolator according to claim 1.

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