JP2006027092A - Mold for molding rubber molded product without burr and requiring no finishing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold for molding a rubber molded product constituted so as not only to prevent the occurrence of burr but also to use no wasteful rubber material. <P>SOLUTION: In the mold for molding the rubber molded product composed of a movable mold and a fixed mold, the pressure contact end surface of either one of the movable mold and the fixed mold is airtightly and elastically brought into contact with the elastic airtight body, which is embedded in the boundary part with a molding space part of the pressure contact end surface of the other one of the movable mold and the fixed mold without forming a gap to mold the rubber molded product in the space part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mold for molding a molded rubber product mainly used for industrial use.

Conventionally, as shown in FIG. 6, the mold K1 for rubber molding for this kind of industrial use is a mold comprising a movable mold 31 and a fixed mold 32 in FIG. A molding space 37 and a gap 34 of the molded product 35 and a crisp (rubber reservoir) space 33 are formed, and vulcanized rubber is vulcanized and molded in the quickly space 33 through the molding space 37 and the gap 34. The rubber molding 35 is molded, and after the molding, the quickly 38 is removed by manual work or machining in a separate process, and the finishing work is performed.

However, in the initial state of the mold, it is easy to remove the quill 38, but as the frequency of use of the mold increases, the wear of the mold gap 34 progresses and the removal operation becomes difficult. Burr appears on the appearance.

In addition, it is necessary to dispose of the quill 38 every time, and it is difficult to recycle synthetic rubber, which has a great influence on environmental problems.

  An object of the present invention is to provide a mold for molding a rubber molded product in which burrs are not generated and unnecessary rubber material is not used.

The present invention relates to a molding die for rubber moldings composed of a movable mold and a fixed mold, wherein one end face pressure contact surface of the movable mold and the fixed mold is replaced with one end face pressure contact surface of the other movable mold and the fixed mold. This is characterized in that the elastic airtight body embedded in the boundary portion with the molding space is elastically contacted without gap and the rubber molded product is molded in the space.

The present invention relates to a molding die for rubber moldings composed of a movable mold and a fixed mold, wherein one end face pressure contact surface of the movable mold and the fixed mold is replaced with one end face pressure contact surface of the other movable mold and the fixed mold. Since the elastic airtight body embedded in the boundary portion with the molding space is elastically contacted without gaps and the rubber molding is molded in the space, no burrs are generated in the rubber molding, Also, since no quilling work is required, the cost can be reduced and mass production can be achieved.

  In addition, since there is no need to dispose of quills, the cost can be reduced by that amount, which contributes to environmental problems with industrial waste.

Hereinafter, the present invention will be described in detail with reference to examples. FIG. 5 includes a movable mold 1, a fixed mold 2, a movable side heat insulating plate 13, a fixed side heat insulating plate 14, a cooling plate 15, a fixed side mounting plate 16, and a movable side mounting plate 17 related to the present invention. 2 is a cross-sectional view when the molding die K is mounted on the injection molding machine S, FIG. 2 is a perspective view of only the movable die 1 and the fixed die 2 of the die K, and FIG. 3 is the AA line of FIG. 4 is an enlarged sectional view taken along line B-B in FIG. 2, and FIG. 1 is an enlarged sectional view of the main part in FIG.

  In FIGS. 1, 2, 3, 4, and 5, the fixed die 2 is in contact with the movable die 1 at the time of clamping, and a molding space portion 5a having a shape on one side of the molding 5 is formed. Four places are press-fitted. In this example, the molded product is an O-ring with a diameter of φ6 mm with a side of 300 mm x 180 mm and a corner of 20 R with a rectangle with curves at four corners. Is provided with a molding space of 3 mm. Further, on the outer side of one of the short sides of the rectangle, a φ4 mm spool 10 for introducing a rubber material is provided at a location 5 mm away from the molding space.

  1, 2, 3, 4, and 5, the movable mold 1 is in contact with the fixed mold 2 at the time of clamping, and a molding space 5 b that is in one shape of the molded product 5 is formed. Four insertion holes 7 that are guided in correspondence with a certain guide pin 7a are recessed. In this example, like the fixed mold 2, a molding space portion having a semicircle with a radius of 3 mm and a depth of 3 mm is provided. A recess 3a provided with an undercut portion 3b is provided in the outer periphery and the inner periphery of the molding space portion with a boundary surface 4 therebetween so that the elastic airtight body 3 cannot escape. As shown in FIG. 1, the airtight body 3 is embedded in the recess 3a so as not to escape airtightly without a gap. When the mold is clamped, the exposed contact surface 3c of the airtight body 3 and the end surface pressure contact of the fixed mold 2 are pressed. The surface 2a is elastically contacted with the end surface pressure contact surface 2a at an appropriate pressure at the time of clamping so as to provide a molding space 5a of the rubber molded product 5 that does not generate burrs in an airtight manner without gaps. The hermetic body 3 is preferably made of a material that can withstand high temperatures and high pressures and has little change in quality and deformation. In this example, hard rubber is used. The space between the molding space portion 5a of the boundary surface 4 and the recess 3a was 0.1 mm, and the height thereof was the same as that of the end surface pressure contact surface 1a. The recess 3a is tapered from the entrance 3c toward the narrowed portion 3d, and the undercut portion 3b is larger than the width of the narrowed portion 3d so that it does not escape. At this time, the width of the entrance 3c was 3 mm, the width of the narrowed portion 3d was 2 mm, and the width of the undercut portion was 2.5 mm. As shown in FIGS. 2 and 4, an injection gate 6 for introducing a rubber material is provided on one outer side of the short side of the rectangular shape of the molding space, and comes into contact with the spool 10 of the fixed mold 2 when the mold is closed. The part is provided with a spool lock 9. In addition, an overflow groove 8 is provided on the other outer side for introducing and absorbing excess material, which serves as both a molding space and a gas vent in the rubber material. In this example, the injection gate 6 has a width of 4 mm and a depth of 0.2 mm, the spool lock 9 has a diameter of φ8 and a depth of 5 mm, the overflow groove 8 has a width of 4 mm and the depth of the boundary 8a with the molding space is 0. The length was 2 mm, the others were 1 mm, and the length was 30 mm.

  First, it is necessary to mold and embed the elastic hermetic body 3 before molding the rubber molding 5. In this embodiment, 150% of the unvulcanized rubber with respect to the capacity of the elastic hermetic body 3 in the mold K is used. Is placed along the groove of the recess 3a, the mold is clamped and heated to vulcanize the elastic airtight body 3, the rubber protruding from the recess 3a is removed after the mold is opened, and the elastic airtight body is cleaned. 3 was molded and embedded. In this example, hard silicon rubber was used.

In order to mold the rubber molding 5 with this mold K, as shown in FIG. 5, the mold K is set in the injection molding machine S, and the necessary amount of unvulcanized rubber is charged from the material inlet. Unvulcanized rubber is injected from the injection machine 20 through the injection nozzle 20a, the cold runner 12, the spool 10, the spool lock 9, and the injection gate 6 into the molding space 5a, and then the mold is clamped and heated to vulcanize the rubber molding 5. Molding is performed, and the molding 5 is taken out of the mold to complete the molding. In FIG. 1, during vulcanization molding, unvulcanized rubber does not enter the gap (0.1 mm) of the boundary surface 4 even though molding pressure is applied to the unvulcanized rubber. Since the internal pressure of the molding space 5a and the recessed portion 3a is almost equal via the boundary surface 4, and the expansion of the airtight body 3 is added to prevent entry, there is no room for burrs. Further, even if the unvulcanized rubber is in pressure contact with the airtight body 3, it does not fuse.

As shown in FIGS. 2 and 4, the overflow groove 8 is provided on the opposite side to the injection gate 6 of the rubber molding 5, so that the molding space portion and the rubber material are specified as the overflow groove 8 which is the final arrival point of the unvulcanized rubber. The gas inside was able to escape, and excess material injected from the injection molding machine could be absorbed there, so there was no gas generation, lack of metal, poor fusion, etc. in the rubber molding 5 It was. In addition, since a part of the thickness of the injection gate 6 and the overflow groove 8 is set thin, the injection gate 6 and the overflow groove 8 can be easily removed by hand in the post-finishing process.

Thus, no burrs are generated in the rubber molded product, and no crisp removal work is required. Further, since the defective rate of rubber products and the yield can be improved, the cost can be reduced and mass production can be achieved. In addition, because there is no quirk, the amount of rubber to be disposed of is reduced to 50% or less, which can reduce the cost and contribute to environmental problems for industrial waste.

  It can be used for the production of rubber not only for industrial rubber moldings but also in all fields that are molded in molds, and has great advantages when automated and mass-produced, including 24-hour non-stop product removal. Is.

It is explanatory drawing of this invention, and is an expanded sectional view of the movable mold | type and fixed mold | type at the time of vulcanization molding. 2 is a perspective view of a movable mold / fixed mold of a mold K. FIG. It is an expanded sectional view of the AA line of FIG. It is an expanded sectional view of the BB line of FIG. It is sectional drawing when the metal mold | die K for molding which concerns on this invention is set to the injection molding machine. It is explanatory drawing of a prior art, and is an expanded sectional view of the movable mold | type and fixed mold | type at the time of vulcanization molding.

Explanation of symbols

K Mold 1 Movable mold 1a End surface pressure contact surface 2 Fixed mold 2a End surface pressure contact surface 3 Elastic airtight body 3a Recess 3b Undercut portion 3c Exposed close contact surface 3d Narrowed portion 4 Boundary surface 5 Rubber molding 5a Molding space portion 6 Injection gate 7 Insertion hole 7a Guide pin 8 Overflow groove 8a Boundary 9 Spool lock 10 Spool 12 Cold runner 13 Movable heat insulating plate 14 Fixed heat insulating plate 15 Cooling plate 16 Fixed side mounting plate 17 Movable side mounting plate 18 Cartridge heater 19 Locating ring 20 Injection Machine 20a injection nozzle
21 Movable platen 22 Fixed platen 23 Tie bar K1 Mold 31 Movable die 32 Fixed die 33 Squeeze (rubber reservoir) space 34 Gap 35 Rubber molding 36 End surface pressure contact surface 37 Molding space 38 Quikiri K2 Mold 41 Movable die 42 Fixed die 43 Burr 45 Rubber molding 46 End face pressure contact surface

Claims (3)

In a mold for rubber molding consisting of a movable mold and a fixed mold, the end space pressure contact surface of either the movable mold or the fixed mold is the molding space portion of the other movable mold or the fixed mold. A mold for molding a rubber molding, characterized in that an elastic airtight body embedded in a boundary portion between the two and the like is elastically contacted without gaps and a rubber molding is molded in the space. 2. The mold for molding a rubber molding according to claim 1, wherein the airtight body has an undercut shape so that the elastic airtight body is not detached. On the opposite side of the rubber material injection part of the rubber molded product, it also serves as a vent for the molding space and the rubber material, introduces a groove for introducing and absorbing excess material, 2. The mold for molding a rubber molded product according to claim 1, wherein the mold is molded.

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