JP2011173380A - Molding die and manufacturing method of tube type damping device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve production efficiency at a low cost when molding a tube type damping device 2 with a tubular body 21 and a rubber elastomer 23 in the body. <P>SOLUTION: A molding die includes a die body 1 which includes a bottom surface (a first surface) 40 adhered to one edge surface in a tubular axis direction of a tubular body 21, an upper surface (a second surface) 30 adhered to the other edge surface in the tubular axis direction of the tubular body 21 and an outer circumferential side surface (a third surface) 50 in contact to the outer circumferential surface of the tubular body 21. In the die body 1, an infusion hole 12 opened in an inner part of a cavity 11 and an air vent hole 13 for exhausting air in the cavity 11 are formed, and in at least one of the bottom surface 40 and the upper surface 30, an escaping concave part 35 which is concaved in order to form a pre-determined space from the edge surfaces of the tubular body 21 is formed in such a way to extend to a pre-determined range in a peripheral direction of the tubular body 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The technology disclosed herein relates to a molding die for molding a cylindrical vibration isolator including a cylindrical body and a rubber elastic body therein, and a method of manufacturing the cylindrical vibration isolator using the molding die. .

  For example, in Patent Document 1, as an anti-vibration device for a vehicle, an outer cylinder, an inner cylinder arranged coaxially with the outer cylinder, a rubber elastic body that couples both between the outer cylinder and the inner cylinder, There is disclosed a mold for molding a cylindrical vibration isolator provided with the above. Specifically, the mold includes an upper mold and a lower mold that define a cavity in which the outer cylinder is held, and a core presser for holding the inner cylinder in each of the upper mold and the lower mold, and The molding die described in this document further leaks unvulcanized rubber injected into the cavity through a gap between the end surface of the inner cylinder and the partition screen of the cavity. In order to prevent this, a seal ring that comes into contact with the outer peripheral surface of the end of the inner cylinder is provided. In other words, since the leaked rubber becomes a burr in the molded product and its deburring process is necessary, in order to eliminate such a finishing process, the molding die described in the above literature should prevent the rubber from leaking out. I have to.

JP 2002-79551 A

  By the way, in the above-mentioned Patent Document 1, there is a problem of leakage from the end surface of the inner cylindrical body. For example, when unvulcanized rubber leaks through a gap between the end surface of the outer cylindrical body and the partition screen of the cavity. There is also. If the unvulcanized rubber leaks out of the outer cylindrical body in this way, burrs are generated in the molded product, so that a deburring finishing process is required.

  As one of the measures to prevent leakage of unvulcanized rubber from the end face of the outer cylindrical body, for example, the mold clamping pressure is further increased, so that the cavity screen and the end face of the outer cylindrical body are brought into close contact with each other. It is possible. However, molds that achieve high mold clamping pressure are more expensive. For example, the more molds that can be molded at a time, that is, the number of molds that can be formed in multiple molds to increase production efficiency. The greater the number, the higher the required clamping pressure.

  Also, even if the clamping pressure is increased, depending on the dimensional accuracy of the outer cylinder, uncured rubber may leak from the end face. It is even more difficult to completely eliminate the processing, and the production efficiency is not necessarily increased. In addition, in such a case, it is impossible to know in advance where the burrs are generated in the circumferential direction of the outer cylinder, and therefore all or one generated burrs must be removed at various positions. As a result, the time required for finishing may become longer.

  The technology disclosed herein has been made in view of the above points, and the object of the technology is to inexpensively form a cylindrical vibration isolator including a cylindrical body and a rubber elastic body therein. It is to increase production efficiency.

  The inventors of the present application do not eliminate the leakage of unvulcanized rubber by increasing the clamping pressure, thereby eliminating the finishing process, and assuming that the finishing process is performed, the finishing process is simplified as much as possible. The mold was studied from the viewpoint of making it easier.

  Specifically, in view of the fact that the clamping pressure required in the molding die is proportional to the area where the surface defining the cavity and the end surface of the cylindrical body abut, the clamping pressure is reduced by reducing the area. We decided to plan. In other words, the relief recess that is recessed so as to form a gap with respect to the end surface of the cylinder is spread over a predetermined range in the circumferential direction of the cylinder on a part of the surface of the mold that is in close contact with the end surface of the cylinder. It was decided to form.

  On the other hand, such an escape recess also allows the inside and outside of the cylinder to communicate between the surface of the mold and the end surface of the cylinder, so that unvulcanized rubber leaks out of the cylinder through the escape recess. As a result, burrs are generated in the molded product. However, in this configuration, it is possible to grasp in advance that burrs are almost certainly generated and that the burrs are generated at the location where the relief recess is formed, so that it is only necessary to remove burrs at predetermined locations of the molded product taken out from the mold. It has been found that the finishing can be performed and the labor and time required for finishing can be reduced, and the present invention has been completed.

  Specifically, the mold disclosed herein is a mold for integrally vulcanizing a cylindrical vibration isolator having a rubber elastic body having a predetermined shape inside the cylinder. The mold has a first surface that contacts the one end surface in the cylinder axis direction of the cylinder, a second surface that contacts the other end surface in the cylinder axis direction of the cylinder, and a third surface that contacts the outer peripheral surface of the cylinder. A mold body having a surface, the first to third surfaces of the mold body hold the cylindrical body, and a cavity into which unvulcanized rubber is injected is defined. An injection hole that opens into the cavity and injects the unvulcanized rubber, and an air vent hole that discharges air in the cavity as the unvulcanized rubber is injected into the cavity. And are formed. Further, at least one of the first surface and the second surface has an escape recess that is recessed so as to form a predetermined gap with the end surface of the cylindrical body within a predetermined range in the circumferential direction of the cylindrical body. It is formed so as to spread over.

  According to this configuration, the escape recess is formed on at least one of the first surface and the second surface defining the cavity so as to spread over a predetermined range in the circumferential direction of the cylindrical body. For this reason, the area where the end face of the cylinder comes into contact with the first surface and the second face is reduced by the amount of the relief recess where a gap is provided between the end face of the cylinder and the required clamping pressure is reduced. . This is advantageous in reducing the cost of the mold.

  On the other hand, the formation of the relief recess that allows the inside and outside of the cylinder to communicate allows the unvulcanized rubber injected into the cavity, that is, into the cylinder, to leak out of the cylinder through the relief recess. Because it is possible to grasp in advance that burrs due to leakage will almost certainly occur in the molded product molded by the above, and that the burrs will occur at the location where the recessed portion is formed, the predetermined location of the molded product removed from the mold Finishing process just to remove the burrs. In other words, after checking the presence or absence of burrs on each molded product, if burrs are generated, it is a complicated process to remove all or one generated burrs at various locations. Finishing is not necessary, and the labor and time required for finishing are reduced, thereby increasing production efficiency.

  Here, the air vent hole has a diameter of the cylindrical body at a predetermined circumferential position so as to communicate the inside and outside of the cylindrical body between the first surface or the second surface and the end surface of the cylindrical body. It is preferable that the relief recess is provided at a location where the air vent hole is formed.

  By forming the air vent hole extending in the radial direction of the cylinder so as to communicate the inside and outside of the cylinder, unvulcanized rubber may leak out of the cylinder through the air vent hole. There is sex. On the other hand, by providing a relief recess where the unvulcanized rubber can leak out at the location where the air vent hole is formed, as a result, the unvulcanized rubber leaks out at the location where the air vent hole and the escape recess are formed, Leakage of unvulcanized rubber at other locations is prevented. This makes it possible to limit the occurrence location of burrs to a specific location (reduction of the occurrence location) and specify the location in advance as described above. That is, labor and time required for finishing are further reduced.

  On the first surface, a seal portion is formed over the entire circumference of the cylindrical body so as to be pressed against the inner peripheral edge of the one end surface of the cylindrical body to prevent leakage of the unvulcanized rubber. In addition, the escape recess may be formed on the second surface.

  By doing so, on the one end face side of the cylindrical body, leakage of unvulcanized rubber is prevented by the seal portion, so that no burrs are generated. On the other hand, on the other end surface side of the cylinder, which is the opposite side, a relief recess is formed, and as described above, unvulcanized rubber can leak and burrs can occur. That is, since burrs are generated only on one end face side of the cylindrical body in the molded product, labor and time required for deburring are further reduced, and production efficiency is further increased.

  The manufacturing method of the cylindrical vibration isolator disclosed here is a manufacturing method using the mold described above. Specifically, the manufacturing method includes the steps of setting the cylindrical body in the cavity, closing the mold, and injecting the unvulcanized rubber into the cavity through the injection hole, After the vulcanized rubber is vulcanized, in the step of taking out the vulcanized integral molded product of the cylindrical body and the rubber elastic body from the mold and in the taken out molded product, the vulcanized rubber is present at a position corresponding to the escape recess. Removing the burrs.

  As described above, since the relief recess is formed in the mold, in the manufacturing method of the cylindrical vibration isolator using this mold, a part of the unvulcanized rubber injected into the cavity is the relief recess. However, it is only necessary to perform the finishing process to remove the burrs that have occurred at the specified locations, reducing the time and effort of the finishing process. , Increase production efficiency.

  As described above, according to the molding die and the manufacturing method described above, in the molding die, the relief recess is provided on at least one of the first surface and the second surface that abuts the end surface of the cylindrical body over a predetermined range in the circumferential direction. The mold clamping pressure can be reduced by forming it so that it is widened, but for the molded product, it is only necessary to perform a finishing process to remove the burrs generated corresponding to the formation of the relief recess. Well, it is possible to increase the production efficiency by reducing the labor and time required for finishing.

It is a partially broken perspective view which shows the cylindrical vibration isolator shape | molded by the shaping | molding die concerning embodiment. (A) The top view of a cylindrical vibration isolator, (b) It is AA sectional drawing of the same figure (a). (A) Bottom view of upper mold of mold, (b) Cross section of mold corresponding to BB cross section of (a). (A) Sectional drawing which expands and shows the contact location of the upper mold | die and an outer cylinder body in a shaping | molding die, (b) Of the contact location of an upper mold | die and an outer cylinder body, the formation location of a relief recessed part is shown. It is sectional drawing which expands, and (c) It is sectional drawing which expands and shows the contact location of the lower metal mold | die and outer cylinder in a shaping | molding die. It is a perspective view which shows the vulcanization integral molded product taken out from the shaping | molding die.

  Hereinafter, an embodiment of a forming die and a manufacturing method using the same will be described with reference to the drawings. The following description of the preferred embodiment is merely exemplary in nature. 1 and 2 show a cylindrical vibration isolator 2 molded by a molding die 1 (see FIG. 3) according to the present embodiment, which is used for a vehicle, for example, as a suspension bush. A device 2, a metal outer cylinder 21, a metal cylinder 22 having a smaller diameter than the outer cylinder 21 and arranged coaxially with the outer cylinder 21, Between the inner peripheral surface of the cylindrical body 21 and the outer peripheral surface of the inner cylindrical body 22, a rubber elastic body 23 that connects them to each other is provided. In this vibration isolator 2, the intermediate cylinder 24 having a smaller diameter than the outer cylinder 21 and larger than the inner cylinder 22 is coaxial with the outer cylinder 21 and the inner cylinder 22. It is embedded in the rubber elastic body 23. In this cylindrical vibration isolator 2, the one end side and the other end side in the cylinder axis direction are formed symmetrically, and there is no particular directionality such as the vertical direction, for example. For convenience, the upper side in FIGS. 1 and 3B may be referred to as the upper side, and the lower side in FIGS. 1 and 3B may be referred to as the lower side.

  The vibration isolator 2 will be described in more detail. The outer cylinder 21 is a relatively thin cylindrical member. In addition, although illustration is abbreviate | omitted, you may form a taper in the outer peripheral surface in each both ends of the cylinder axial direction of the outer cylinder body 21. As shown in FIG.

  The inner cylinder 22 is a relatively thick cylindrical member, and its length in the cylinder axis direction is longer than that of the outer cylinder 21. As a result, the inner cylindrical body 22 inserted into the outer cylindrical body 21 has both end portions in the cylindrical axial direction projecting outward from the end portions of the outer cylindrical body 21 (see, for example, FIG. 2B). ).

  As shown in FIG. 2A, the intermediate cylinder 24 is formed as a cylinder as a whole by arranging a pair of halved members (half cylinders 241) so as to abut each other at a predetermined interval. It is comprised so that it may become a shape. The intermediate cylinder 24 is set to have a length in the cylinder axis direction slightly shorter than that of the outer cylinder 21, and as shown in FIG. In the cross section, it is arranged at a substantially central position between the outer cylinder 21 and the inner cylinder 22.

  As described above, the rubber elastic body 23 is connected between the inner peripheral surface of the outer cylindrical body 21 and the outer peripheral surface of the inner cylindrical body 22 with each other over the entire circumference. A concave groove 231 extending in the circumferential direction between the outer cylinder 21 and the intermediate cylinder 24 and between the intermediate cylinder 24 and the inner cylinder 22 is formed on each end face in the cylinder axis direction of the rubber elastic body 23. Is formed. In addition, two projecting portions 232 projecting outward in the radial direction from the outer peripheral surface of the inner cylindrical body 22 at intervals of 180 ° in the circumferential direction, respectively, at both ends in the cylindrical axis direction of the inner cylindrical body 22. The rubber elastic body 23 is integrally formed.

  3 and 4 show a part of the mold 1 for integrally vulcanizing the cylindrical vibration isolator 2. In other words, the mold 1 has a plurality of cavities 11 so that, for example, a plurality of cylindrical vibration isolator 2 can be molded at a time, although not shown in the drawing, Only one of the cavities 11 is extracted and shown. The molding die (die body) 1 includes an upper die 3, a lower die 4 and an intermediate die 5, and the upper die 3, the lower die 4 and the intermediate die 5 are combined. The cavity 11 is partitioned and formed therein.

  The upper mold 3 is a mold for defining the upper surface (second surface) 30 of the cavity 11, and has a central recess 31 to which a support pin 39 for supporting the inner cylindrical body 22 is attached. An annular groove 32 that holds the upper end of the intermediate cylinder 24 (half cylinder 241) and the upper end of the outer cylinder 21 are extrapolated on the outer peripheral side of the central recess 31 and the upper end of the outer cylinder 21 is inserted. And an annular convex portion 33 that holds A screw hole 311 is formed in the central recess 31 of the upper mold 3, and the screw portion 391 of the support pin 39 is screwed into the screw hole 311, thereby being inserted into the upper end portion of the inner cylindrical body 22. The support pins 39 are disposed so as to protrude downward from the upper mold 3. As shown in FIG. 3A, the annular groove 32 is formed into a ring shape as a whole by a pair of semi-circular grooves 321 being abutted so as to correspond to the half-shaped half cylinder 241. A positioning projection 322 for positioning the half cylinder is provided between the pair of semicircular concave grooves 321. Further, a recess 323 for forming the upper protrusion 232 in the cylindrical vibration isolator 2 is formed at a predetermined circumferential position in the annular recess 32, and the recess 321 is formed by the recess 323. Has become divided. The annular convex portion 33 is provided adjacent to the annular concave groove 32 in the radial direction, and is provided so as to protrude downward. An injection hole 12 for injecting unvulcanized rubber in communication with the cavity 11 is formed in the upper mold 3 so as to extend in the vertical direction. The injection hole 12 is formed in the annular groove. In a radial position corresponding to 32, two positions are opened at a circumferential position corresponding to the middle between the positioning protrusion 322 and the recess 323 and spaced from each other by 180 °.

  Thus, in the upper mold 3, an annular contact surface 34 that contacts the upper end surface of the outer cylindrical body 21 that is extrapolated to the annular protrusion 33 is formed on the outer peripheral side in the radial direction of the annular protrusion 33. ing. Here, as shown in an enlarged view in FIG. 4A, the contact surface 34 is configured to contact the upper end surface of the outer cylinder 21 over the entire surface in the thickness direction. . Further, as shown in FIG. 3A, two air vent holes 13 are formed in the contact surface 34 with an interval of 90 ° with respect to the injection holes 12. Therefore, each air vent hole 13 is formed at a position farthest from the injection hole 12 in the circumferential direction. The air vent hole 13 is formed so as to be recessed from the contact surface 34 of the upper mold 3 as shown in, for example, an enlarged view in FIG. On the other hand, a predetermined gap is formed. In the example shown in the drawing, the depth of the air vent hole 13 is exaggerated from the actual depth for easy understanding. The air vent hole 13 is formed to extend in the radial direction so as to communicate the inside and outside of the outer cylindrical body 21, and as a result, unvulcanized rubber is injected into the cavity 11 through the injection hole 12. The air in the cavity 11 is discharged out of the outer cylindrical body 21 through the air vent hole 13 in the radial direction.

  Thus, a relief recess 35 is formed in the contact surface 34 of the upper mold 3 at the position where each of the air vent holes 13 is formed. As shown in FIG. 4B, each of the relief recesses 35 is formed so as to be recessed from the contact surface 34, and forms a predetermined gap with respect to the upper end surface of the outer cylindrical body 21, in other words, the outer recesses 35 The upper end surface of the cylindrical body 21 is a non-contact portion, and is formed so as to spread over a predetermined angular range θ in the circumferential direction as shown in FIG. Accordingly, the contact surface 34 of the upper mold 3 is in contact with the upper end surface of the outer cylinder 21 because the area where the escape recess 35 is formed is not in contact with the upper end surface of the outer cylinder 21. The area is reduced accordingly. Although the depth of the escape recess 35 is exaggerated from the actual depth in the illustrated example from the viewpoint of easy understanding, the depth of the escape recess 35 is also shown in the figure. Moreover, it is preferable that the depth of the air vent hole 13 is shallower. That is, the air vent hole 13 preferably has a predetermined cross-sectional area from the viewpoint of reliably discharging the air in the cavity 11, and the air vent hole 13 that does not spread in the circumferential direction, such as the escape recess 35, The depth can be relatively deep. The air vent hole 13 may have a so-called small hole shape between the contact surface 34 and the upper end surface of the outer cylindrical body 21. On the other hand, the relief recess 35 only needs to be in non-contact with the upper end surface of the outer cylinder 21 and is formed to extend over a predetermined angular range in the circumferential direction. Thus, there is an inconvenience that the amount of unvulcanized rubber that leaks out of the outer cylindrical body 21 through the relief recess 35 increases. Therefore, the relief recess 35 may be formed relatively shallow.

  The intermediate mold 5 is a mold that partitions and forms a peripheral side surface (third surface) 50 of the cavity 11 between the upper mold 3 and the lower mold 4. An insertion hole 51 constituting the side surface 50 is provided. A lower mold 4 to be described later is inserted into a lower end portion of the insertion hole 51, and an outer cylindrical body 21 is inserted into an intermediate portion thereof. In addition to the contact surface 44 (seal part) of the lower mold 4, an annular contact surface 52 that contacts the lower end surface of the outer cylinder 21 is formed (see FIG. 4C). Further, a taper whose diameter is enlarged is formed at the upper end portion of the insertion hole 51 in order to improve the insertion of the outer cylindrical body 21 into the cavity.

  The lower mold 4 is a mold for defining a lower surface (first surface) 40 of the cavity 11, and, like the upper mold 3, a central recess to which a support pin 49 for supporting the inner cylindrical body 22 is attached. 41 and an annular groove 42 that holds the lower end of the intermediate cylinder 24 (half cylinder 241) and the lower end of the outer cylinder 21 are extrapolated on the outer peripheral side of the central recess 41. And an annular convex portion 43 that holds the lower end portion of the outer cylindrical body 21. The central recess 41 is also formed with a screw hole 411 into which the screw portion 491 of the support pin 49 is screwed, whereby the support pin 49 inserted into the lower end portion of the inner cylindrical body 22 is removed from the lower mold 4. It arrange | positions so that it may protrude upwards. Although the detailed illustration is omitted, the annular groove 42 is also formed in an annular shape as a whole by abutting a pair of semicircular concave grooves as in the case of the upper mold 3. Positioning projections are formed between the arc-shaped concave grooves. A difference from the upper mold 3 is that a predetermined portion in the circumferential direction of the annular groove 42 of the lower mold 4 is formed with a holding portion 423 for holding the lower end of the semi-cylindrical body 241 in the thickness direction. Thus, the half cylinder 241 is held in an upright posture in the cavity 11. The annular convex portion 43 is provided adjacent to the annular concave groove 42 in the radial direction, and is provided so as to protrude upward. An annular contact surface 44 that contacts the lower end surface of the outer cylindrical body 21 that is extrapolated to the annular protrusion 43 is formed on the outer circumferential side of the annular protrusion 43 in the radial direction. As shown in an enlarged view in FIG. 4C, the contact surface 44 is set so as to contact the inner peripheral edge of the outer cylindrical body 21 over the entire periphery, as will be described later. When the molding die 1 is clamped, the inner peripheral edge of the outer cylindrical body 21 is pressed against the lower end surface of the outer cylindrical body 21. This prevents unvulcanized rubber from leaking out of the outer cylinder 21 through the space between the lower end surface of the outer cylinder 21 and the contact surface 44 of the lower mold 4 during molding. The contact surface functions as a seal portion that prevents leakage of unvulcanized rubber. In the following description, the same reference numeral “44” may be assigned to the “contact surface” and the “seal portion”.

  Next, the molding procedure of the cylindrical vibration isolator 2 using the molding die 1 will be briefly described. First, with the mold 1 opened, the outer cylinder 21, the inner cylinder 22, and the pair of half cylinders 241 are respectively disposed at predetermined positions in the cavity 11. Then, the mold 1 is closed. Here, as described above, two escape recesses 35 are provided on the contact surface 34 of the upper mold 3, and the contact surface 34 of the upper mold 3 and the outer cylindrical body are provided by the escape recess 35. The contact area with the upper end surface of 21 becomes small. The necessary mold closing pressure is reduced by the reduction of the area. That is, the mold 1 is configured such that a necessary mold closing pressure is relatively low. On the other hand, the seal portion 44 of the lower mold 4 crushes the inner peripheral edge of the lower end of the outer cylinder 21.

  When the clamping of the mold 1 is completed, unvulcanized rubber is injected into the cavity 11 through the two injection holes 12. At this time, since the seal portion 44 of the lower mold 4 is pressed so as to crush the lower end surface of the outer cylindrical body 21, it is certain that the unvulcanized rubber leaks through the lower end surface of the outer cylindrical body 21. To be prevented. On the other hand, as described above, a relief recess 35 is formed in the contact surface 34 of the upper mold 3, and the inside and outside of the outer cylinder 21 communicate with each other through the relief recess 35 on the upper end side of the outer cylinder 21. Therefore, the unvulcanized rubber leaks out of the outer cylindrical body 21 through the escape recess 35 and the air vent hole 13.

  Then, vulcanization integral molding is performed by heating, the mold 1 is opened, and the vulcanization integral molded product 6 composed of the outer cylinder 21, the inner cylinder 22, the intermediate cylinder 24, and the rubber elastic body 23 is taken out. For example, as shown in FIG. 5, the molded product 6 taken out here is a rubber through the relief recess 35 and the air vent hole 13 at a position corresponding to the formation location of the relief recess 35 on the upper end surface of the outer cylinder 21. 1 is formed, and the cylindrical vibration isolator 2 as shown in FIG. 1 is obtained by finishing the burr 61 manually or by machining. It will be completed. Here, as shown in FIG. 1, the rubber elastic body 62 which is a part of the burr 61 may remain in the vicinity of the upper end surface of the outer cylindrical body 21 of the cylindrical vibration isolator 2.

  As described above, according to the manufacturing method of the mold 1 and the cylindrical vibration isolator 2 using the mold 1, the contact surface 34 of the upper mold 3 is allowed to escape over a predetermined angle range θ. By forming the recess 35, the contact area with the upper end surface of the outer cylinder 21 is reduced. Since the mold clamping pressure of the mold 1 is proportional to the contact area, the reduction of the contact area reduces the necessary mold clamping pressure. That is, the mold 1 can be molded with a relatively low clamping pressure. For example, in a mold that molds a plurality of molded products at a time, the required clamping pressure increases as the number of moldings increases. Therefore, a configuration that enables molding with a lower clamping pressure as described above. Is particularly effective in that the required clamping pressure can be greatly reduced in the multi-molding mold 1.

  While the clamping pressure is reduced, the escape recess 35 communicates the inside and outside of the outer cylinder 21 due to its structure, so that the unvulcanized rubber injected into the cavity 11 can be removed by this escape recess. The burrs 61 are generated in the molded product 6 by leaking out of the outer cylindrical body 21 through 35. However, since this burr 61 is grasped in advance in the molded product 6 at the location where the relief recess 35 is formed, the burr 61 generated at two predetermined locations of the molded product 6 is removed as shown in FIG. What is necessary is that it does not require much time and effort for deburring. Such deburring finish processing may be performed manually, but in particular, since the generation location of the burr 61 is always the same location, it is possible to perform the deburring finishing processing by machining. The finishing process is further simplified and shortened.

  Further, the escape recess 35 is provided at a position where the air vent hole 13 is formed. Since the air vent hole 13 also has a structure for communicating the inside and outside of the outer cylindrical body 21, unvulcanized rubber. This can cause leakage. Thus, providing the escape recess 35 and the air vent hole 13 that can cause the leakage of the unvulcanized rubber at the same location concentrates the location where the leakage of the unvulcanized rubber occurs, and the molded product 6 This has the effect of reducing the number of burrs 61 generated in the process. This also contributes to the simplification of the finishing process.

  Further, in the molding die 1, the contact surface of the lower mold 4 is used as a seal portion 44, and the lower end of the outer cylinder 21 is closely contacted so that the lower end side of the outer cylinder 21 is made of unvulcanized rubber. Since the leakage is surely prevented, it is possible to limit the occurrence location of the burr 61 in the molded product 6 only to the upper end of the outer cylinder 21. That is, since the generation | occurrence | production location of the burr | flash 61 decreases, it becomes advantageous to the simplification of a finishing process. In addition, since the sealing part 44 is provided only in the lower mold 4 and the upper end surface of the outer cylindrical body 21 is not crushed by the sealing part, the illustration is omitted, but in the completed cylindrical vibration isolator 2, the outer cylindrical body 21 is omitted. While the upper end surface of the plate is substantially flat, a step can be formed on the lower end surface inside and outside in the radial direction.

  Thus, it is possible to increase the production efficiency at a low cost when the cylindrical vibration isolator 2 is molded.

  Here, the larger the range in which the escape recess 35 is formed, the lower the mold clamping pressure. On the other hand, the greater the range of the escape recess 35 is, the more unvulcanized rubber leaks out. Means that the generated burr 61 becomes larger. This adversely affects the finishing process. For this reason, it is preferable to set the range in which the relief recess 35 is formed from the viewpoints of both the clamping pressure and the amount of unvulcanized rubber leakage. For example, in the case where the relief recesses 35 are provided at two positions with an interval of 180 ° as in the above-described mold, the angle range of one escape recess 35 is in the range of about 30 ° to 90 °, preferably 60 °. You may set in the range before and behind.

  In the molding die 1, the escape recesses 35 are formed in two places, but the number of the escape recesses 35 is not particularly limited. Normally, in the mold, the number of air vent holes corresponding to the number of injection holes provided therein is provided, but the number of relief recesses 35 may also be provided according to the number of air vent holes. . However, the number of relief recesses 35 and the number of air vent holes 13 do not necessarily match. For example, more escape recesses 35 may be formed than the air vent holes 13. Further, when the air vent hole is not formed so as to extend in the radial direction at the end surface of the outer cylindrical body 21 as in the molding die 1, for example, as in the injection hole 12 of the molding die 1, In the case where it is formed so as to extend in the direction, the relief recess 35 is not formed at the location where the air vent hole is formed. Therefore, restrictions on the number and location of the relief recesses 35 can be relaxed or eliminated. .

  Further, in the molding die 1, the escape recess 35 is formed only in the upper mold 3, but the escape recess 35 is provided in the lower mold 4 depending on how the opening position of the injection hole 12 is provided, for example. The relief recess 35 may be formed on both the upper mold 3 and the lower mold 4.

  Further, in the molding die 1 described above, the seal portion 44 is provided only on the contact surface of the lower mold 4, but the seal portion may also be provided on the contact surface 34 of the upper mold 3. That is, the inner peripheral edge of each of the upper end surface and the lower end surface of the outer cylinder 21 may be crushed. However, the formation range of the relief recess 35 and the air vent hole 13 is excluded. Here, the crushing amount of the end surface of the outer cylinder 21 is set so that the end surface is reliably crushed according to the dimensional tolerance of the length of the outer cylinder 21 in the cylinder axis direction. For example, in the configuration in which the seal portion 44 is provided only on the contact surface of the lower mold 4 as in the molding die 1 described above, only the lower end side of the outer cylindrical body 21 is crushed, so the crushed amount (L) is simply It is only necessary to set it to be larger than the dimensional tolerance (T) (L> T, for example, L = T + α). On the other hand, as described above, in the configuration in which each of the upper end surface and the lower end surface of the outer cylindrical body 21 is crushed, the dimensional tolerance (T) of the outer cylindrical body 21 is divided into the upper end side and the lower end side (T / 2, T / 2), the crushing amount (L1, L2) larger than the divided dimension tolerance must be set on each of the upper end side and the lower end side of the outer cylindrical body 21 (L1> T / 2, L2> T / 2, for example L1 = T / 2 + α, L2 = T / 2 + α). In this case, the total crushing amount (L1 + L2 = T + 2α) is larger than the crushing amount (L = T + α) in the case of crushing only one end side of the outer cylinder 21, so that the necessary mold clamping pressure is correspondingly increased. Can be bigger. That is, the configuration in which the seal portion 44 is provided only in the lower mold 4 as in the above-described mold 1, in other words, the configuration in which only one end surface of the outer cylinder 21 is crushed reduces the necessary clamping pressure. Can be advantageous.

  Note that the molding die that can reduce the clamping pressure and can be easily finished as disclosed herein is not limited to the molding of the cylindrical vibration isolator 2 having the intermediate cylinder 24 as described above. The present invention can also be applied to molding of a cylindrical vibration isolator without the intermediate cylinder 24. In addition, the present invention can be widely applied to the molding of various types of cylindrical vibration isolator for vehicles having a cylinder and having a rubber elastic body in a predetermined shape therein. Furthermore, the object to be molded is not limited to a tubular vibration isolator for a vehicle.

  In addition, the technology disclosed herein is not limited to the molding of rubber molded products, but is also a technology that can be applied to molding of various plastic materials. The present invention is not limited to this, and can be applied to the manufacture of various products.

  As described above, the manufacturing method of the mold disclosed herein and the cylindrical vibration isolator using the same can reduce the necessary clamping pressure and simplify the finishing process. When molding the mold vibration isolator, the production efficiency can be increased at low cost, which is useful.

DESCRIPTION OF SYMBOLS 1 Mold 11 Cavity 12 Injection hole 13 Air vent hole 2 Cylindrical vibration isolator 21 Outer cylinder (cylinder)
23 Rubber elastic body 30 Upper surface (second surface)
34 Contact surface 35 Relief recess 40 Lower surface (first surface)
44 seal part 50 peripheral side surface (3rd surface)
6 Molded product 61 Bali

Claims (4)

A mold for integrally vulcanizing a cylindrical vibration isolator provided with a rubber elastic body of a predetermined shape inside a cylinder,
A first surface that contacts the one end surface in the cylinder axis direction of the cylinder, a second surface that contacts the other end surface in the cylinder axis direction of the cylinder, and a third surface that contacts the outer peripheral surface of the cylinder. With mold body,
The first to third surfaces of the mold body hold the cylinder and define a cavity into which unvulcanized rubber is injected,
The mold body opens into the cavity and has an injection hole for injecting the unvulcanized rubber, and the air in the cavity is discharged as the unvulcanized rubber is injected into the cavity. An air vent hole is formed,
At least one of the first surface and the second surface has an escape recess that is recessed so as to form a predetermined gap with the end surface of the cylindrical body over a predetermined range in the circumferential direction of the cylindrical body. Mold that is formed to spread. The mold according to claim 1, wherein
The air vent hole extends in a radial direction of the cylindrical body at a predetermined circumferential position so as to communicate the inside and outside of the cylindrical body between the first surface or the second surface and the end surface of the cylindrical body. Formed,
The relief recess is a molding die provided at a location where the air vent hole is formed. In the mold according to claim 1 or 2,
On the first surface, a seal portion is formed over the entire circumference of the cylindrical body so as to be pressed against the inner peripheral edge of the one end surface of the cylindrical body to prevent leakage of the unvulcanized rubber. And
The relief die is a molding die formed on the second surface. It is a manufacturing method of the cylindrical vibration isolator using the shaping | molding die of any one of Claims 1-3,
Setting the cylinder in the cavity;
Closing the mold and injecting the unvulcanized rubber into the cavity through the injection hole;
After vulcanizing the unvulcanized rubber, removing the vulcanized integral molded product of the cylindrical body and the rubber elastic body from the mold; and
The manufacturing method including the step of removing burrs present at positions corresponding to the relief recesses in the removed molded product.

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