JP2011131503A - Molding die for cylindrical rubber and method for molding cylindrical rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ameliorated molding die for cylindrical rubber which can solve conventional troubles such as an installation space tending to increase due to high fabrication precision and high manufacturing cost caused by a split mold, and also, resultantly, the possible yielding of a non-conforming product and the possible worsening of outward appearance, and which as a result of the shooting of the troubles, enables a realizing of the simplification of the structure and consequent cost saving, the decrease of the fraction defective and improvement of outer appearance. <P>SOLUTION: The molding die for cylindrical rubber is configured as follows. The lower end part 13 is diametrally crimped to externally encircle and receive the cylindrical rubber D to be expanded under pressure from the inside. Further, the lower end has an undercut surface 3b which is folded to the radial outside, and thus, the molding surface M is cylindrical with a strictured lower end. Besides, the molding die is constituted of a bottom force 4 for forming the lower end part 13, a top force 1 and an intermediate force 2 which externally encircle the upper end from slightly below the undercut surface 3b, and a ring-shape undercut force 3 with the undercut surface 3b. The inside diameter of the minimum diametral part of the undercut force 3 is preset to a size larger than the minimum outside diameter which allows the cylindrical rubber D of the maximum diametral part of the intermediate force 2 to be distorted due to its elastic shrinkage. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the present invention, in order to surround and receive the cylindrical rubber pressurized and expanded from the inside, the diameter is reduced so that the diameter becomes smaller as one end portion in the axial direction approaches the one end in the axial direction, and The present invention relates to a cylindrical rubber molding die having an undercut surface at which the outermost end of one end portion is folded outward and having a cylindrical molding surface.

  Air springs used in vehicles such as trucks and buses have a so-called rolling diaphragm structure, and for example, those disclosed in Patent Document 1 (FIG. 1) and Patent Document 2 (FIG. 1) are known. ing. As shown in FIG. 3 of Patent Document 1 and FIG. 2 of Patent Document 2, the diaphragm used for this air spring for trucks and buses is considerably larger in the axial direction length than the radial length as shown in FIG. It is generally long and has a tapered cylindrical shape with one end or both ends constricted.

  In order to produce a cylindrical rubber having a narrowed tip as described above, an unvulcanized cylindrical rubber (many rubbers containing reinforcing fibers) placed in a mold are placed inside a bladder (rubber bag). ) Is heated and swelled to press against the molding surface of the mold, thereby forming and vulcanizing the shape. Examples of such a technique include “diaphragm vulcanization mold for air spring” disclosed in Patent Document 3, “rubber heating bladder for vulcanization of tire or air spring” disclosed in Patent Document 4, and the like. Are well known.

  As shown in FIG. 5, a conventional mold C for forming a diaphragm for an air spring is roughly composed of an upper mold 21, an intermediate mold 22, a divided mold 23, and a lower mold 24. Three arcuate molds 23a are arranged in the circumferential direction. Three sets of opening / closing devices 25 for driving the arc-shaped molds 23a to open / close and move to the operating position and the retracted position are provided. Each opening / closing device 25 includes a fluid pressure cylinder 26 and a parallel link mechanism 27. ing. That is, since the diameter of the lower end portion is reduced so that the diameter becomes smaller as the lower end portion is closer to the lower end, and the outermost end of the lower end portion has an undercut surface 23b that is turned back to the outside of the diameter, Therefore, it is impossible to perform mold removal by dividing the circumferential direction into three parts and moving the respective circular arc dies 23a radially outward. It was.

  However, the mold C having the conventional structure requires a large number of parts and requires high finishing accuracy, the mold structure is complicated, and the undercut surface 23b is divided in the circumferential direction. Therefore, it was disadvantageous in terms of defect rate. That is, the following 1. ~ 4. There was a problem like this, and there was room for improvement.

  1. At least two or more divided molds are necessary for the diameter-expanded portion of the diaphragm, and when combined, a circular shape must be maintained and high machining accuracy is required. 2. A dedicated opening / closing device (such as a cylinder) is required to set and separate the split mold (lower mold), which is disadvantageous in terms of installation space and cost. 3. If the misalignment of the split mold occurs at the time of setting to the lower mold, there is a possibility that the expanded diameter portion of the diaphragm is sandwiched between the split mold and the lower mold and crushed. 4). A split surface (mold split stripe) in the vertical direction (diaphragm axis direction) is formed in the split mold portion of the diaphragm, which may adversely affect the appearance quality.

JP 2006-071045 A JP 2006-264204 A JP 2000-052348 A JP-A-9-123175

  The object of the present invention is to solve the problems 1. ~ 4. Improved, that is, high processing accuracy by split mold and split type switchgear are necessary, and the installation space is increased at high cost, and there is a risk of defective products due to misalignment due to split mold opening and closing, and appearance An improved cylindrical rubber molding die and cylindrical rubber molding method that eliminate the conventional inconvenience such as the occurrence of split surfaces that adversely affect the surface, simplify the structure, reduce the cost, reduce the defective rate, and improve the appearance. The point is to provide.

In the invention according to claim 1, in order to surround and receive the cylindrical rubber D pressurized and expanded from the inside, the diameter of the one end 13 in the direction of the axis P decreases toward the one end in the direction of the axis P. In a cylindrical rubber molding die having an undercut surface 3b that is reduced in diameter and has an undercut surface 3b in which the outermost end of the one end portion 13 is folded outwardly, and having a cylindrical molding surface M.
The one end side end mold 4 for forming the outermost end of the one end portion 13 and the other end in the axis P direction from the base end of the undercut surface 3b or a position slightly closer to the one end side than the base end. The other end side molds 1, 2, and the ring-shaped undercut mold 3 including the undercut surface 3 b between the one end side end mold 4 and the other end side molds 1, 2.
The inner diameter of the minimum diameter portion of the undercut mold 3 is set to a dimension equal to or larger than the minimum outer diameter that allows the cylindrical rubber D of the maximum diameter portion of the other end side molds 1 and 2 to be elastically deformed. It is what.

  According to a second aspect of the present invention, in the cylindrical rubber molding die according to the first aspect, the diameter decreases as the other end 1 of the other end side molds 1 and 2 approaches the other end in the axis P direction. The other end diameter-reducing surface ts is reduced.

In the invention according to claim 3, in order to surround and receive the cylindrical rubber D that is pressurized and expanded from the inside, the diameter of the one end 13 in the direction of the axis P decreases toward the one end in the direction of the axis P. The cylindrical rubber is molded using a molding die A having an undercut surface 3b whose diameter is reduced to the outside and the end 13 of the one end portion 13 is turned back to the outside of the diameter and having a cylindrical molding surface M. In the cylindrical rubber molding method,
As the mold A, the one end side end mold 4 for forming the outermost end of the one end portion 13 and the base end of the undercut surface 3b or a position slightly closer to the one end side from the base end in the axis P direction. The other end side molds 1 and 2 surrounding the other end, and the ring-shaped undercut mold 3 including the undercut surface 3b between the one end side end mold 4 and the other end side molds 1 and 2 Prepare what you have,
In the demolding step after molding, in which the cylindrical rubber D is pressurized and expanded from the inside and pressed against the molding surface M, the other end side molds 1 and 2 of the molded cylindrical rubber D are exposed by demolding. A forced demolding step is included in which the undercut mold 3 is moved in the direction of the axis P by elastically deforming the portion Dr, thereby passing over the exposed portion Dr and demolding. Is.

  According to a fourth aspect of the present invention, in the cylindrical rubber molding method according to the third aspect, as the other end side molds 1 and 2 in the molding die A, the other end portion is closer to the other end in the axis P direction. What is used is one having the other-end diameter-reduced surface ts that is diameter-reduced so as to be smaller.

  According to the invention of claim 1, the details will be described in the section of the embodiment, but the undercut surface that has been conventionally formed by using the divided mold divided in the circumferential direction is utilized by utilizing the elasticity of the cylindrical rubber. By changing the concept of forced demolding, it became possible to mold with a ring-shaped undercut mold. This simplifies mold processing, eliminates the need for incidental equipment, simplifies the structure of the mold, reduces costs, reduces equipment space, and reduces the bottom end of the cylindrical rubber due to misalignment between the split molds. There is no risk of pinching or crushing, an effect of reducing the defect rate is obtained, and since the parting surface in the axial direction is eliminated, it is possible to contribute to the appearance improvement of the cylindrical rubber product.

  As a result, high processing accuracy by the split mold and a split-type opening / closing device are required, and the installation space increases at a high cost. Thus, it is possible to provide an improved mold for cylindrical rubber that eliminates the conventional inconvenience such as the occurrence of a split surface that increases the thickness, simplifies the structure, reduces the cost, reduces the defect rate, and improves the appearance. Such an effect can also be obtained by a cylindrical rubber mold having a tapered shape at both ends and having a diameter-reduced surface at the other end.

  According to the invention of claim 3, it is possible to provide a cylindrical rubber molding method that obtains the same effect as the effect of the invention of claim 1. Moreover, according to the invention of Claim 4, the cylindrical rubber molding method which obtains an effect equivalent to the effect by the invention of Claim 2 can be provided.

Sectional drawing which shows schematic structure of the shaping | molding die for cylindrical rubbers (Example 1) (A) is sectional drawing which shows unvulcanized cylindrical rubber, (b) is an operation | movement figure which shows a setting process The operation diagram of the cylindrical rubber molding method is shown, (a) is the molding process, (b) is the main demolding process. (A) is an operational view showing a forced demolding step, (b) is a half sectional view of a cylindrical rubber after molding Sectional drawing which shows schematic structure of the conventional mold for cylindrical rubber

  Embodiments of a cylindrical rubber molding die and a cylindrical rubber molding method according to the present invention will be described below with reference to the drawings.

[Example 1]
FIG. 1 is a cross-sectional view of a cylindrical rubber mold A (hereinafter simply referred to as “mold A”) for molding an air spring diaphragm suitably used for trucks and buses. The mold A includes an upper mold (an example of the other end side mold) 1, a middle mold (an example of the other end side mold) 2, an undercut mold 3, a lower mold (an example of the one end side end mold) 4, and a holding jig. 5 is configured in a substantially cylindrical shape. The holding jig 5 is for fixing the undercut mold 3 to the lower mold 4. The upper mold 1, the middle mold 2, and the lower mold 4 are formed with annular passages 1t, 2t, and 4t through which heating steam is passed.

  The molding die A includes a molding surface M including an inner surface 1a of the upper die 1, an inner surface 2a of the middle die 2, an inner surface 3a of the undercut die 3, an undercut surface 3b which is a lower ceiling surface, and a top peripheral surface 4a of the lower die 4. have. That is, in order to surround and receive the cylindrical rubber D pressurized and expanded from the inside, the diameter becomes smaller as the lower end portion (one example of one end portion) in the axis P direction approaches the lower end (one end) in the axis P direction. The lower end portion (one end portion) has an undercut surface 3b that is folded back to the outer diameter and the upper end portion in the axis P direction (the other end portion). Part) has a cylindrical forming surface M with both ends constricted with the other-end diameter-reduced surface ts that is reduced in diameter so that the diameter becomes smaller toward the upper end (the other end). The cylindrical rubber D becomes a diaphragm for an air spring as a product by molding with the mold A.

  The ring-shaped undercut mold 3 has a downward projecting ring ridge 7 fitted into an upwardly open annular groove 6 formed on the upper surface 4 b of the lower mold 4. By fitting with the ring ridges 7, the undercut mold 3 can be incorporated into the lower mold 4 in a positioned state. The undercut die 3 is formed with the upper surface 4b of the lower die 4 and a presser upper surface 7a in a state of being partially bite inward in the circumferential direction on the ring ridge 7 at the same height level. At a position corresponding to the upper surface 7a of the presser in the vertical direction, a laterally recessed portion 8 is formed that bites in the radially inward direction.

  The presser jig 5 includes an upper arm portion 5A having a length extending over the upper surface 4b of the lower mold 4 and the presser upper surface 7a, and a lower arm portion 5B that can be inserted into the laterally recessed portion 8. It is deployed at multiple locations for each uniform angle. The holding jig 5 is configured such that the upper arm portion 5A is moved to the upper surface 4b and the holding upper surface 7a by lateral movement in a state in which the ring ridge 7 is fitted in the annular groove 6 and the undercut die 3 is disposed on the lower die 4. In addition, the undercut mold 3 can be assembled to the lower mold 4 so as not to come out upward by fitting the lower arm part 5B so as to be positioned in the lateral recess 8 respectively. Therefore, the undercut die 3 can be moved upward and removed from the lower die 4 by the lateral movement (removal movement) of the holding jig 5 from the state shown in FIG.

  Next, a cylindrical rubber molding method will be described. First, as shown in FIG. 2 (a), a substantially cylindrical unvulcanized cylindrical rubber (called green) D having a lower end expanded downward and an upper end slightly reduced in diameter is prepared. As shown in FIG. 2 (b), a setting process is performed in which the unvulcanized cylindrical rubber D and bladder B are assembled and set in the mold A. The cylindrical rubber D has an upper end portion (which is an upper bead portion as a product) 12 locked and fixed to the upper mold 1 using an upper mounting jig J, and a lower end portion (a lower bead portion as a product). 13) is mounted on the mold A in a state of being sandwiched between the undercut mold 3 and the lower mold 4. The substantially cylindrical bladder B whose upper part is slightly narrowed from the center in the vertical direction is locked and fixed to the upper mold 1 in such a positional relationship that its upper end 11 is below the cylindrical rubber D using the upper mounting jig J. And the lower end part 14 is set in the state mounted in the upper expansion inclination side peripheral surface 4c of the lower mold | type 4 using the lower mounting jig K. As shown in FIG.

  The upper mounting jig J is composed of an upper jig part 9 for holding the upper end part 12 of the unvulcanized cylindrical rubber D and a lower jig part 10 for holding the upper end part 11 of the bladder B. The upper jig portion 9 is fitted to the stepped upper end inner surface portion 1 b of the upper mold 1. Although not shown and marked, the lower jig portion 10 is screwed with a lower holding case that sandwiches the upper end portion 11 of the bladder B up and down, an upper holding case, and a bolt that integrates the upper and lower holding cases. Means. Although not shown and notated, the lower mounting jig K includes a lower clamping case that sandwiches the lower end portion 14 of the bladder B up and down, an upper clamping case, and screws such as bolts that integrate the upper and lower clamping cases together. It is comprised from the wearing means.

  Next, the bladder B is expanded to expand the cylindrical rubber D from the central portion in the direction of the axis P, and the cylindrical rubber D is pressed against the molding surface M of the mold A as shown in FIG. The molding process is performed. In this molding process, the cylindrical rubber D pressed against the molding surface M is heated and thereby vulcanized, and is also referred to as a “vulcanization process”. By this molding process, the rubber is molded into a cylindrical rubber D that has been vulcanized into a product shape. In FIG. 2B and FIG. 3A, the upper mold 1 and the middle mold 2 are not shown for simplicity.

  When the vulcanization process is finished, a main demolding process of removing the cylindrical rubber D from the mold A is performed. In the main demolding step, as shown in FIG. 3 (b), the vulcanized cylindrical rubber D is removed from the lower mold 4 together with the undercut mold 3. This is because the cylindrical rubber D is forcibly expanded and molded by the bladder B, and the lower end of the cylindrical rubber D has a shape along the reduced diameter surface is, so that the undercut die 3 is sandwiched between the lower ends of the cylindrical rubber D after molding and vulcanization. This is because they are in a state in which both 3 and D are integrated.

  Following the main demolding process, a forced demolding process of removing the undercut mold 3 from the cylindrical rubber D is performed. Since the cylindrical rubber D is rubber and can be elastically reduced in diameter, as shown in FIG. 4A, the cylindrical rubber D is forcibly elastically reduced in diameter and then the undercut mold 3 is relatively moved. It is possible to extract the cylindrical rubber D by moving it upward. This is possible because the inner diameter d3 of the minimum diameter portion of the undercut mold 3 is set to a dimension equal to or larger than the minimum outer diameter dm that allows the cylindrical rubber D of the maximum diameter portion of the middle mold 2 to be elastically deformed. Technology. The diameter dt of the middle part 2 of the cylindrical rubber D shown in FIG. 4A is drawn as being smaller than the inner diameter d3 of the minimum part and larger than the minimum outer diameter dm (d3> dt> dm). In other words, the molded portion of the cylindrical rubber D by the middle mold 2 can be elastically deformed until the undercut mold 3 can be passed.

  The cylindrical rubber D from which the undercut mold 3 has been removed and the diameter reducing means has been removed is restored (expanded) to the shape formed by its own elasticity, and the cylindrical rubber as the product shown in FIG. D is completed. Therefore, the cylindrical rubber D that has passed a predetermined time from the forced demolding process is shipped as a cylindrical rubber for trucks and buses as a product. The main demolding process and the forced demolding process can be collectively defined as “demolding process”.

  That is, in the demolding step after molding in which the cylindrical rubber D is pressurized and expanded from the inside and pressed against the molding surface M, the upper die 1 and the middle die 2 (the other end side die 1, 1) in the cylindrical rubber D after molding. 2) includes a forced demolding step in which the undercut mold 3 is moved in the direction of the axis P by overdrawing the exposed portion Dr by elastically deforming the exposed portion Dr from which the mold has been removed. It is.

  In other words, in order to surround and receive the cylindrical rubber D that is pressurized and expanded from the inside by the bladder B, the one end portion in the axis P direction (lower end portion) approaches the lower end (one end) in the axis center P direction. Mold A having an undercut surface 3b that is reduced in diameter so that the lower end (one end) is folded back to the outside of the diameter and has a cylindrical molding surface M that is narrowed at the lower end (one end). Is a cylindrical rubber molding method of molding cylindrical rubber D using And as the shaping | molding die A, the lower mold | type 4 which is a lower end (one end) side end type | mold for forming the outermost end of the lower end (one end) part 13, and the base end of the undercut surface 3b, or a little one end side from there Between the upper die 1 and the middle die 2 that are the other end side die that surrounds the other end (upper end) in the axis P direction from the portion that has been removed, and the lower die 4 and the other end side die 1 that are the one end side end die. A mold having a ring-shaped undercut die 3 having an undercut surface 3b is prepared, and in the demolding process after molding, the cylindrical rubber D is pressurized and expanded from the inside and pressed against the molding surface M. The undercut die 3 is moved in the direction of the axis P by elastically reducing the diameter of the exposed portion Dr where the upper die 1 and the middle die 2 as the upper die (other end) side die of the cylindrical rubber D are removed. Includes a forced demolding process in which the exposed portion Dr is passed over and demolded. A cylindrical rubber molding methods.

  In the cylindrical rubber molding die A according to the present invention, the undercut surface 3b that has been conventionally molded using a split die that is divided into three in the circumferential direction is forcibly removed using the elasticity of the cylindrical rubber D. As a result of the conversion, the ring-shaped undercut mold 3 can be formed, and the following advantages are obtained. That is, the die machining (die machining) is simplified and ancillary equipment (such as the opening / closing device 25 shown in FIG. 5) is not required, and the structure of the mold can be simplified, the cost can be reduced, and the equipment space can be reduced ( The above problems 1 and 2 are solved). Further, there is no risk of pinching or crushing of the lower end of the cylindrical rubber due to the positional deviation between the split dies when the unvulcanized cylindrical rubber D is set in the mold A, and an effect of reducing the defective rate is obtained (described above). (3) is solved). In addition, since there is no parting surface in the vertical direction (axial center P direction), it is possible to contribute to the improvement of the appearance of the cylindrical rubber D as a product (the above-mentioned problem 4 is eliminated). That is, it is advantageous in terms of quality, cost, and product aesthetics.

[Another Example]
In the first embodiment, the mold A for making the cylindrical rubber D of the both ends reduced diameter type in which the upper end portion is also reduced is introduced. However, the upper end portion (the other end portion) is not reduced in diameter and is a straight (or almost straight) cylindrical shape. A lower end (one end) reduced diameter type cylindrical rubber molding die or a cylindrical rubber molding method may be used.

1 Other end type (upper mold)
2 Other end side type (Medium type)
3 Undercut mold 3b Undercut surface 4 One end side mold 13 One end A Mold D D Rubber rubber Dr Exposed part M Molded surface P Axis ts Other diameter reduced surface

Claims (4)

In order to enclose and receive the cylindrical rubber pressurized and expanded from the inside, one end portion in the axial center direction is reduced in diameter so that the diameter decreases toward the one end in the axial direction, and the end portion of the one end portion is reduced. A cylindrical rubber molding die having an undercut surface whose end is folded outward and having a cylindrical molding surface that is narrowed at one end,
One end side mold for forming the outermost end of the one end, and the other end mold that surrounds the other end in the axial direction from the base end of the undercut surface or a position slightly closer to the one end side than the base end And a ring-shaped undercut mold comprising the undercut surface between the one end side end mold and the other end side mold,
A cylindrical rubber molding die in which an inner diameter of a minimum diameter portion of the undercut die is set to a size equal to or larger than a minimum outer diameter at which the cylindrical rubber of the maximum diameter portion of the other end side mold can be elastically deformed.   2. The mold for cylindrical rubber according to claim 1, wherein the other end portion of the other end side mold has a diameter-reduced surface at the other end which is reduced in diameter so that the diameter becomes smaller toward the other end in the axial direction. . In order to enclose and receive the cylindrical rubber pressurized and expanded from the inside, one end portion in the axial center direction is reduced in diameter so that the diameter decreases toward the one end in the axial direction, and the end portion of the one end portion is reduced. A cylindrical rubber molding method in which a cylindrical rubber is molded using a molding die having an undercut surface whose end is folded outwardly and having a cylindrical molding surface.
As the molding die, one end side end die for forming the outermost end of the one end portion, and the other end in the axial direction from the base end of the undercut surface or a position slightly closer to the one end side than the base end Preparing the other end side mold, and a ring-shaped undercut mold provided with the undercut surface between the one end side end mold and the other end side mold,
In the demolding process after molding in which the cylindrical rubber is pressurized and expanded from the inside and pressed against the molding surface, the exposed portion of the molded cylindrical rubber from which the other end side mold has been demolded is elastically deformed. A cylindrical rubber molding method including a forced demolding step in which the undercut mold is moved in the axial direction so as to pass through the exposed portion and demold.   The said other end side type | mold in the said shaping | molding die is what has an other end diameter reduction surface diameter-reduced so that a diameter may become so small that an other edge part approaches the other end in an axial direction. Cylindrical rubber molding method.

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