JP2006137076A - Method for producing annular rubber gasket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a new annular rubber gasket which makes a molding be detached easily during demolding and can improve production efficiency. <P>SOLUTION: In the method for producing the annular rubber gasket 2 having a concave channel 2a along an interior part, a mold 4 in which the cross-sectional shape of a cavity 4a formed by the combination parts of split molds 5, 6, and 7 is made an approximately contrary shape in the radial direction as compared with the cross-sectional shape of the desired annular rubber gasket 2 is prepared. After a rubber material is packed in the cavity 4a of the mold 4 and molded, the split molds 5, 6, and 7 are separated. An obtained annular rubber molding 20 is deformed elastically, and its interior and peripheral parts are reversed mutually to obtain the desired annular rubber gasket 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention, for example, manufactures an annular rubber gasket (water inlet gasket) for sealing a connecting portion of a pipe in a holding portion of a fluid device such as a thermostat disposed in the middle of a cooling water conduit for a radiator of an automobile engine or the like. Regarding the method.

  FIG. 1 shows an example of a cooling water piping system in which a fluid device such as a thermostat as described above is provided. FIG. 1 also shows a piping system to which an annular rubber gasket obtained by the manufacturing method of the present invention is applied. A thermostat 1 includes a thermostat body 1a disposed in a flow path of cooling water, and a thermostat body 1a. The disk-shaped holding member 1b is held so as to be positioned at the center of the flow path. An annular rubber gasket (water) targeted by the manufacturing method of the present invention is formed on the outer peripheral edge of the disk-shaped holding member 1b. Inlet gasket) 2 is mounted. The annular rubber gasket 2 is interposed between the joint flanges 3 a and 3 a of the cooling water pipe 3, and the flanges 3 a and 3 a are fastened with bolts and nuts (not shown), so that the thermostat 1 is connected to the pipe 3. The holding portion is sealed by the annular rubber gasket 2 held in the middle and interposed in an elastically compressed state. The annular rubber gasket 2 includes an annular groove 2a having a shape that can be fitted to the outer peripheral edge portion of the disc-shaped holding member 1b along the inner peripheral portion thereof.

Patent Document 1 discloses a molding die (molding die) for molding an annular rubber gasket (an elastomer annular body) provided with the annular groove as described above. This mold consists of three divided molds, an upper mold, a lower mold, and a core mold (core). When these divided molds are combined and combined, an object having an annular groove along the inner peripheral portion is provided. An annular cavity having the same cross-sectional shape as the elastomeric annular body is formed. A desired elastomeric annular body can be obtained by charging a rubber material into the annular cavity and molding it, and then removing the three divided molds sequentially.
Japanese Utility Model Laid-Open No. 2-148311

  When molding an annular rubber gasket having an annular groove on the inner periphery by the molding die as described above, the molded product wound around the outer periphery of the core mold (core) at the time of demolding, It can be removed with a suitable tool. Such removal work requires both skill and labor, and may cause a reduction in manufacturing efficiency. In addition, when each of the split molds includes a plurality of mold parts and a plurality of molded products are collectively formed by multi-molding, a reciprocating shaft is provided for each of a plurality of core molds (cores) in a mold such as Patent Document 1. On the other hand, when such a reciprocating shaft is not provided, it is necessary to manually insert a plurality of core types (cores) individually or to remove them when removing the mold. In the former case, the apparatus becomes large. However, in the latter case, improvement in production efficiency could not be expected despite the multi-molding.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel manufacturing method of an annular rubber gasket that can easily remove a molded product at the time of demolding and can improve manufacturing efficiency. Yes.

  The manufacturing method of the annular rubber gasket according to the invention of claim 1 is a manufacturing method of an annular rubber gasket having an annular groove along the inner peripheral portion, and is formed by a plurality of split-type merged portions. After preparing a molding die whose cross-sectional shape is substantially opposite to the cross-sectional shape of the desired annular rubber gasket in the radial direction, a rubber material is loaded into the annular cavity of the molding die and molded, The split mold is removed, the obtained annular rubber molded product is elastically deformed, and the inner peripheral portion and the outer peripheral portion are inverted with respect to each other to obtain the desired annular rubber gasket.

  In the method for producing an annular rubber gasket according to the invention of claim 2, in the above, the annular rubber molded product obtained after the demolding has an annular groove along the outer periphery, and the annular groove is formed by the inversion. It is located in the inner peripheral part. In this case, as in a third aspect of the present invention, the plurality of divided molds include a lower mold, an intermediate mold, and an upper mold, and the intermediate mold is formed along the outer peripheral portion of the annular rubber molded product. A male part corresponding to a concave groove is provided, and when the three divided molds are combined, the male part is inserted into a space formed by a lower mold and an upper female part from the outer peripheral part. A cavity may be formed. Furthermore, as in the invention of claim 4, the lower mold, the middle mold and the upper mold are each composed of a multi-type having a plurality of female mold sections and male mold sections on a single base. The annular rubber molded product can be batch molded.

  The annular rubber gasket obtained by the manufacturing method of the present invention is, as in the fifth aspect of the invention, provided between the connecting portions of the fluid piping so as to seal the holding portion of the fluid device disposed in the middle of the fluid conduit. It is interposed, and it is desirable that the annular concave groove of the inner peripheral portion has a shape that can be fitted to the outer peripheral edge portion of the plate-like holding member of the fluid device.

  According to the manufacturing method of the annular rubber gasket according to the invention of claim 1, claim 2 or claim 3, since the annular concave groove in the obtained molded product is located at the outer peripheral portion of the annular body, The molded product can be easily removed by extruding the inner peripheral portion side in combination with the elasticity of the rubber, with the annular concave groove being held in the split mold. In addition, if each of the divided types is a multi-type as in the invention of claim 4, in particular, since the middle type in place of the conventional core is provided with a plurality of male parts, it is possible to handle them in a lump. As before, there is no need to insert individual cores as in the past, or to remove individual cores holding molded products when removing the mold, greatly improving the efficiency of multi-molding. To do. Furthermore, even when a reciprocating shaft as in Patent Document 1 is adopted, the middle mold can be moved up and down by one reciprocating means, and the apparatus does not increase in size.

  Further, as in the invention of claim 5, the annular rubber gasket obtained by the manufacturing method of the present invention is provided between the connecting portions of the fluid piping so as to seal the holding portion of the fluid device disposed in the middle of the fluid conduit. If it is inserted, it contributes to the cost reduction of the fluid device itself, and if the reversal is performed when fitted to the outer peripheral edge of the plate-like holding member, the fitting is performed. It is easy to simplify the assembling work of the fluid device.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view and a partially enlarged view of an essential part showing an example of a piping system to which an annular rubber gasket obtained by the manufacturing method of the present invention is applied, and FIG. 2 is a state at the time of molding based on the manufacturing method of the present invention. FIG. 3 is a longitudinal sectional view showing a state when the mold is removed, FIG. 4A is a longitudinal sectional view showing a state where the molded product is taken out together with the middle mold, and FIG. 3B is a sectional view showing the molded product from the middle mold. The longitudinal cross-sectional view which shows the removed state, (c) is a longitudinal cross-sectional view which shows a final product. FIG. 5 is a partially cutaway longitudinal sectional view showing a demolding state in multi-molding which is a second embodiment of the present invention.

  FIG. 1 shows an example in which a thermostat 1 is disposed in the middle of a cooling water circulation system pipe for a radiator of an automobile engine. The thermostat 1 includes a valve body that operates according to a change in temperature of a fluid, as indicated by white arrows. It operates by detecting the temperature of the flowing cooling water, and adjusting the opening and closing of the flow path. The thermostat 1 is composed of the thermostat main body 1a and the disc-like holding member 1b as described above, and is formed between the connecting flanges 3a and 3a of the cooling water pipe 3 by the annular rubber gasket ( A disc-shaped holding member 1b fitted with a (water inlet gasket) 2 is sandwiched and supported. An annular concave groove 2a is formed on the inner peripheral portion of the annular rubber gasket 2 to be fitted and attached to the outer peripheral edge portion of the disc-like holding member 1b. The connecting flanges 3a and 3a are fastened with bolts and nuts (not shown), whereby the thermostat 1 is held in the middle of the pipe 3, and the annular rubber gasket 2 interposed in an elastically compressed state is used. The holding part is sealed.

  One example of the manufacturing method of the annular rubber gasket 2 will be described with reference to FIGS. FIG. 2 shows a state at the time of molding based on this manufacturing method, and the molding die 4 is composed of three divided molds of a lower mold 5, a middle mold 6 and an upper mold 7, and the three divided molds 5, 6, 7 is formed with an annular cavity 4a having a shape substantially opposite to the cross-sectional shape of the annular rubber gasket 2 as a final product in the radial direction. The lower mold 5 includes a female mold portion 5a that is recessed in a circular shape. On the lower mold 5, a plate-shaped middle mold 6 having a circular hole having a smaller diameter than the female mold portion 5a is concentrically placed. In this state, the peripheral edge portion of the circular hole of the plate-shaped middle mold 6 protrudes in the center direction of the female mold part 5a to form a lateral male part 6a that enters the annular cavity 4a from the outer peripheral part.

  The upper die 7 includes a cylindrical male die portion 7a having a smaller diameter than the circular hole of the middle die 6 and a concentric annular female die portion 7b around the circular die. The outer diameter of the female mold part 5a is the same. The upper mold 7 is placed on the middle mold 6 as shown in the figure, and the male and female mold parts 5a, 7a, 7b of the lower mold 5 and the upper mold 7 are formed by the overlapping combination of the three divided molds 5, 6, 7. The annular cavity 4a is formed in such a manner that the lateral male part 6a of the plate-shaped middle mold 6 enters from the outer peripheral part into the annular space formed by the above. The shape of these male and female mold parts is not limited to those shown in the drawings, and it goes without saying that, for example, the corners may be R-shaped with appropriate curvature. Reference numerals 5b and 6b are burr grooves.

  Molding by the mold 4 having the above-described configuration can be performed by either hot pressing or injection molding. In the case of the former hot-pressure molding, a rubber material formed in an unvulcanized annular shape at the time of assembling the split dies 5, 6 and 7 is placed at the corresponding figure position of the cavity 4a, and the split dies 5, Vulcanization molding is performed by the mutual stacking pressure of 6 and 7. In the case of the latter injection molding, after assembling the split dies 5, 6, and 7, an unvulcanized rubber material is injected from an injection port (not shown), loaded into the cavity 4a, heated and vulcanized. Molding is done. The state of FIG. 2 shows a state in which the unvulcanized rubber material 2r is loaded into the cavity 4a by any one of the above methods.

  FIG. 3 shows a state of demolding after the above molding is completed, and the upper mold 7 and the middle mold 6 are sequentially demolded from the lower mold 5 as shown in the figure. The rubber molded product 20 has an annular shape, and is taken out in a state of being held by the inner peripheral edge of the circular hole of the middle die 6, that is, the laterally facing male die 6 a. FIG. 4 shows a procedure for removing the annular rubber molded product 20 held on the middle mold 6 to obtain a final product. FIG. 4A shows a state in which the annular rubber molded product 20 is held by the laterally facing male mold portion 6a of the middle die 6 as described above, and the inner peripheral portion of the annular rubber molded product 20 faces upward or downward in this state. If it is made to extrude, the holding | maintenance in the male type | mold part 6a is open | released by elastic deformation peculiar to rubber | gum, and the annular | circular shaped rubber molded product 20 is easily removed from the middle type | mold 6. FIG. This removal does not involve the skill and inconvenience of taking out by pulling while pulling in the diameter-expanding direction with an appropriate tool, etc., as in the case where a molded product is wound around the outer periphery of the core, This process is extremely simple, and this process does not cause a reduction in production efficiency.

  FIG. 4B shows a state in which the annular rubber molded product 20 has been removed from the middle mold 6, and this annular rubber molded product 20 has an annular concave groove 20a corresponding to the male mold portion 6a on the outer periphery thereof. I have. Then, when the ring-shaped portion of the annular rubber molded product 20 is held and reversely deformed in the center direction so as to be hidden inside the ring, the elastic recovery action of the rubber causes the inner and outer sides to move as shown in FIG. An inverted toroid is obtained. This is an annular rubber gasket 2 as a final product according to the manufacturing method of the present invention, and an annular concave groove 2a is provided on the inner peripheral portion thereof. Therefore, when applied to the seal of the arrangement portion of the thermostat 1 as shown in FIG. 1, the outer peripheral edge portion of the disc-shaped holding member 1 b is fitted into the annular groove 2 a to connect the cooling water pipe 3. An annular rubber gasket 2 can be disposed between the flanges 3a and 3a. As the rubber material, any one selected from NBR, H-NBR, ACM, AEM, FKM and the like is desirably employed.

  FIG. 5 shows an example of multi-molding and shows a state of demolding. That is, the lower mold 5, the middle mold 6 and the upper mold 7 are each composed of a multi-type having a plurality of female mold parts 5a, 7b and male mold parts 6a, 7a on a single base 50, 60, 70. A plurality of the annular rubber molded products 20 can be molded together. The lower mold plate base body 50 is formed with a plurality of female mold parts 5a similar to the above, and the medium mold plate base body 60 is formed with a plurality of circular holes at positions corresponding to the female mold parts 5a. The inner peripheral edge of this circular hole is a laterally facing male part 6a. Further, the upper mold plate substrate 70 includes a plurality of male mold portions 7a similar to the above at positions corresponding to the circular holes of the medium mold plate substrate 60 and the female mold portions 5a of the lower mold plate substrate 50. And the female-type part 7b is formed. Accordingly, by stacking the base bodies 50, 60, 70 as the split molds 5, 6, 7, a plurality of the same annular cavities 4a (see FIG. 2) are formed, and each cavities 4a is filled with unvulcanized rubber. Then, by performing a treatment such as heating, a plurality of annular rubber molded products 20 are collectively molded.

  In this multi-molding, a plurality of core functions can be simultaneously developed by simply placing the middle mold base 60 having the male mold parts 6a... With a plurality of circular holes on the lower mold base 50. Therefore, as in the conventional multi-molding, the troublesome work of manually inserting the cores one by one into the predetermined position or taking out the molded product together with the core at the time of demolding is unnecessary. The production efficiency can be dramatically improved. The procedure for removing the annular rubber molded product 20 from the medium-sized substrate 60 and further inverting it inside and outside to obtain the annular rubber gasket 2 as the final product as shown in FIG. As with, it is extremely simple and efficient, and the mass productivity by multi-molding is further improved.

  In the above-described embodiment, an example in which the annular rubber gasket 2 obtained by the manufacturing method of the present invention is applied to a seal of a portion holding a fluid device such as a thermostat in the middle of a coolant circulation system pipe of an automobile engine will be described. However, the present invention is not limited to this, and it is needless to say that the annular rubber gasket according to the manufacturing method of the present invention can be applied when a rubber gasket having an annular concave groove along the inner peripheral portion is required. Further, by combining only the lower mold and the upper mold, it is possible to configure a mold in which the cross-sectional shape of the cavity is substantially opposite to the cross-sectional shape of the desired annular rubber gasket in the radial direction. Therefore, it is easy to remove the molded product, and by inverting the molded product inside and outside, it is possible to easily obtain a desired annular rubber gasket having an annular groove on the inner periphery. Further, the rubber gasket is not limited to an annular shape, and the manufacturing method of the present invention can be applied to a shape corresponding to an application site such as a square, other polygons, an ellipse, and an oval as long as it is annular. is there.

It is the longitudinal cross-sectional view and partial enlarged view of the principal part which show an example of the piping system to which the cyclic | annular rubber gasket obtained by the manufacturing method of this invention is applied. It is a longitudinal cross-sectional view which shows the state at the time of shaping | molding based on the manufacturing method of this invention. It is a longitudinal cross-sectional view which shows the state at the time of the same mold release. (A) is a longitudinal cross-sectional view which shows the state which took out the molded product with the middle mold, (b) is a longitudinal cross-sectional view which shows the state which removed the molded product from the middle mold, (c) is a longitudinal cross-sectional view which shows a final product. It is a longitudinal cross-sectional view which shows the state of demolding in the multi-molding which is 2nd Example of this invention.

Explanation of symbols

1 Thermostat (fluid equipment)
DESCRIPTION OF SYMBOLS 1b Plate-shaped holding member 2 Annular rubber gasket 2a Annular groove 20 Annular rubber molded product 20a Annular groove 3 Cooling water piping (fluid pipe)
3a Flange (joint part)
4 Mold 4a Annular cavity 5 Lower mold (split mold)
5a Female mold part 50 Lower mold base 6 Medium mold (split mold)
6a Male mold part 60 Medium mold base 7 Upper mold (split mold)
7a Male mold part 7b Female mold part 70 Upper mold base

Claims (5)

A method for producing an annular rubber gasket having an annular groove along an inner periphery,
A molding die is prepared in which the cross-sectional shape of the annular cavity formed by the merged portion of the plurality of split dies is substantially opposite to the cross-sectional shape of the desired annular rubber gasket in the radial direction. After the rubber material is loaded into the cavity and molded, the split mold is removed, the obtained annular rubber molded product is elastically deformed, and the inner peripheral portion and the outer peripheral portion are reversed with respect to each other to obtain the desired annular rubber. A method for producing an annular rubber gasket, characterized in that a gasket is obtained. In the manufacturing method of the annular rubber gasket according to claim 1,
The annular rubber molded product obtained after the demolding has an annular groove along the outer periphery, and the annular groove is located on the inner periphery by the inversion. In the manufacturing method of the annular rubber gasket according to claim 2,
The plurality of split molds include a lower mold, an intermediate mold, and an upper mold, and the intermediate mold includes a male mold portion corresponding to an annular groove formed along the outer peripheral portion of the annular rubber molded product, The annular rubber is characterized in that when the three divided molds are combined, the annular cavity is formed such that the male mold part enters from the outer peripheral part into a space formed by the lower and upper male and female mold parts. Manufacturing method of gasket. In the manufacturing method of the annular rubber gasket according to claim 3,
Each of the lower mold, the middle mold and the upper mold is a multi mold having a plurality of female mold sections and male mold sections on one base, and a plurality of the annular rubber molded products can be molded at once. An annular rubber gasket manufacturing method characterized by the above. In the manufacturing method of the annular rubber gasket according to any one of claims 1 to 4,
The annular rubber gasket is interposed between connecting portions of fluid piping to seal a holding portion of a fluid device disposed in the middle of the fluid conduit, and the annular groove in the inner peripheral portion is A method for producing an annular rubber gasket, wherein the annular rubber gasket has a shape that can be fitted to an outer peripheral edge of a plate-like holding member of the fluid device.

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