JPH07112492A - Manufacturing method of bottomed cylinder made of rubber and molding die used in this manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] There is no risk of burr remaining on the bottomed cylinder obtained.
Moreover, it is an object of the present invention to provide a method of manufacturing a bottomed cylindrical body in which burrs are unlikely to remain on the mold and cleaning of the mold is not required every time molding is completed, and a molding mold used in this manufacturing method. [Structure] An upper end 10a of a lower die 10 of a molding die 100 is provided with a large number of endless partition grooves 11 for forming respective back surfaces of bottomed cylindrical bodies,
An upper surface 10a of the lower mold 10 is covered with an unvulcanized rubber sheet 1 having a predetermined size including a large number of partition grooves 11. After that, the middle die 20 having the tubular portion 21 for forming the outer peripheral surface of the bottomed tubular body is matched with the lower die 10, and most of the unvulcanized rubber sheet 1 is pressed and supplied to the tubular portion 21, The core body 31 provided in the upper die 30 is fitted into the tubular portion 21, and most of the unvulcanized rubber sheet 1 pressed and supplied to the tubular portion 21 is replaced with the tubular portion 21 and the core body 31.
And the vulcanization molding is performed on the connection molded product 5 having the partition mountain 4 corresponding to the partition groove 11, and the bottomed cylindrical body 2 is torn along the inner circumference of the partition mountain 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bottomed cylindrical body made of rubber such as a heat conductive rubber cap for radiating heat generated by transistors, ICs, etc. to the atmosphere, and molding used for this method. Regarding molds.

[0002]

2. Description of the Related Art Conventionally, when FIG. 5 is used for convenience, as shown in FIG. 5, a heat conductive rubber cap 2 having a thin thickness of about 300 μm, a width of 20 mm, a height of 5 mm and a height of about 25 mm is used. Is
The plasticized unvulcanized rubber extruded from the nozzle hole of the injection molding machine and the unvulcanized rubber put into the chamber are provided to obtain the mold sprue, runner, and many rubber caps. These cavities are filled with unvulcanized rubber through gates or injection holes arranged for each cavity, and by applying temperature and pressure for a certain period of time, vulcanizing multiple caps with one mold. A method of manufacturing a rubber bottomed cylinder to be molded is known.

[0003]

However, in the conventional method for manufacturing a rubber-made bottomed cylinder as described above, a part of a molded product (bottomed cylinder) corresponding to each of the many cavities corresponds to a gate or an injection hole. While there is burrs on the body, burrs tend to remain on the gate or injection hole of the molding die, so deburring work and cleaning of the molding die are required for each molded product, which causes the cost of the molded product to be high. is doing.

If the bottomed cylindrical body to be vulcanized and molded has a small wall thickness, if the gate and the injection hole are enlarged, the molded product is easily broken when the mold is disassembled and the cavity is filled with unvulcanized rubber. It takes a lot of time, and there is a problem that the filling of the cavity is insufficient for a rubber type having a bad flow.

The present invention has been invented in view of the above problems, and there is no fear that burrs will remain on the obtained bottomed cylindrical body, and burrs will not easily remain on the mold, and the mold will be completed after each molding. The first object is to provide a method of manufacturing a bottomed cylindrical body made of rubber that can substantially eliminate the need for cleaning, and a molding die used in this manufacturing method. The other purpose is to provide a molding die with a conventional cavity. No need for a gate or injection hole for each cavity, filling the cavity easily and reliably, and a rubber bottomed cylinder that can be easily obtained without breaking the vulcanized bottomed cylinder And to provide a molding die used in this manufacturing method.

[0006]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the first means is a method for producing a bottomed tubular body made of rubber; forming an unvulcanized rubber sheet of a predetermined size. On the upper surface of a lower mold having an upper surface with a plurality of partitioning grooves for endlessly partitioning each bottom for forming the back surface of the bottom of each of the bottomed cylindrical bodies. A step of covering the unvulcanized rubber sheet including the plurality of partition grooves;
A plurality of cylindrical portions penetrating in the up-down direction having inner peripheries that substantially match the respective inner contours of the plurality of partition grooves for forming the outer peripheral surfaces of the plurality of bottomed cylindrical bodies. Of the unvulcanized rubber sheet placed on the upper surface of the lower mold by aligning a middle mold disposed above the lower mold, which is relatively separable from the lower mold, with the lower mold. A step of pressing and supplying most of it to the cylindrical portion of the middle mold; the upper mold disposed above the middle mold and being relatively separable from the middle mold and the lower mold substantially as the lower mold The mold is closed, and a plurality of cores forming the inner surface of the bottomed cylinder protruding downward from the lower surface of the upper mold are fitted into the cylinder of the middle mold, and the cylinder and the core are fitted. The gap is formed by filling the majority of the unvulcanized rubber sheet supplied to the cylindrical portion of the medium size with the core body and filling it in accordance with the plurality of partition grooves. A step of vulcanizing the consolidated moldings which are connected to each other in a sheet-like Barigomu through the partition Mountains;
And a step of tearing off the bottomed tubular body of the connected bottomed tubular body from the sheet-shaped burr rubber, which is a method for producing a bottomed tubular body made of rubber.

The second means is a molding die used for manufacturing a rubber bottomed cylinder; an endless type for forming a bottom surface of a large number of bottomed cylinders on a substantially upper surface. A lower mold having a large number of partitioning grooves that are partitioned: Relative to the lower mold having a plurality of vertically penetrating cylindrical portions for forming the outer peripheral surfaces of the respective bottomed cylindrical bodies. Consisting of a middle mold disposed above the lower mold so as to be separated from each other; and an upper mold provided above the middle mold so as to be relatively separated from the middle mold; When closed, the upper mold protrudes downward from the lower surface of the upper mold for forming the inner surface of the bottomed cylindrical body, and is pressed into the plurality of cylinders provided in the middle mold. And the inner peripheral edges of the lower ends of the plurality of cylindrical portions provided in the middle die are in proximity to the inner sides of the partition grooves of the lower die. Is obtained by constituting the molding die used in the preparation of the rubber cylindrical body, characterized in that is provided so as to contact the adjacent state.

[0008]

With the structure as described above, when the middle mold is fitted to the lower mold, most of the unvulcanized rubber sheet placed on the lower mold can be supplied into the middle mold cylinder and the middle mold cylinder can be supplied. The inner peripheral edge of the lower end of the portion can be brought into close contact with or close to the inside of each of the lower partition grooves via the remaining unvulcanized rubber sheet.

Thereafter, when the upper mold is closed with respect to the lower mold via the middle mold, the core body provided in the upper mold crushes most of the unvulcanized rubber sheet supplied into the tubular portion while crushing the middle mold. While it can be filled in the gap between the tubular portion and the core, the remaining unvulcanized rubber sheet is filled in the partition groove of the lower mold,
By extending and spreading in a sheet shape and applying heat in this state, it is possible to vulcanize and form a connected molded product that is connected with sheet-shaped burr rubber through partition mountains formed according to a number of partition grooves. On the other hand, when the upper mold and the middle mold are opened, the connected molded product can be easily removed from the lower mold without leaving burrs on these molds.

When the bottomed cylindrical body is pulled from the sheet-shaped burr rubber of the connected molded product, the sheet-shaped burr rubber can be easily left with a partition mountain without breaking the bottomed cylindrical body without burr. It can be easily torn off.

[0011]

Embodiments of the present invention will be described below with reference to FIGS. In the figure, reference numeral 100 denotes a molding die. The molding die 100 includes a lower die 10, a middle die 20 provided above the lower die 10 so as to be separated from the lower die 10, and a middle die 2.
It is composed of an upper mold 30 which can be separated above 0 and can be closed with respect to the lower mold 10. Then, by using the molding die 100, a large number of bottomed cylindrical bodies 2 shown in FIG. 8 can be manufactured.

More specifically, the lower mold 10 has an upper surface 10a,
A rectangular shallow recess 12 that forms a back surface 2a 'of the bottom 2a of the bottomed tubular body 2 is provided, and a number of partition grooves 11 that are adjacent to the recess 12 and are partitioned into an endless shape having a triangular cross section are provided in a predetermined small size. They are evenly spaced apart. The partition groove 11 may be adjacent to the recess 12. Further, it may be flush with the upper surface 10a of the lower mold 10 without providing the concave portion 12. In the square of the lower mold 10, the lower mold 10
A guide pin 40 is planted so that the middle die 20 provided above the lower die 10 can be easily aligned with the lower die 10 at a predetermined position.

The middle die 20 is provided in the lower die 10 and is provided with the dividing groove 1
In order to correspond to No. 1, a large number of cylindrical portions 21 that penetrate through in the up-down direction for forming the outer peripheral surface of the bottomed cylindrical body 2 are provided. The inner peripheral shape of the tubular portion 21 substantially matches the inner contours of the partition grooves 11 partitioned endlessly.

An upper die 30 which can be separated from the middle die 20 and the lower die 10 is provided above the middle die 20 so that the lower die 10 can be fitted to the middle die 20 and then to the middle die 20. There is.

That is, the facing holes 2 facing each other on the upper surfaces 20a of both ends of the middle mold 20 and the lower surfaces 30a of both ends of the upper mold 10.
0b and 30b are provided, and a compression coil spring 50 capable of supporting the middle die 20 and the upper die 30 at a constant interval is held in the facing holes 20b and 30b in the vertical direction.

Therefore, when the upper die 30 is closed with respect to the lower die 10 or the lower die 10 is closed with respect to the upper die 30, first, the lower die 10 and the middle die 20 are matched with each other, and then the middle die 20 and the upper die 30 are joined together. The mold 30 is devised so that it can be matched. In addition,
If the compression coil spring 50 is not provided, an actuator (not shown) that can independently drive the middle die 20 in the vertical direction may be provided.

On the lower surface 30a of the upper die 30, a cylindrical core body 31 forming the inner surface of the bottomed tubular body 2 projects downward so that it can be fitted into each tubular portion 21 of the middle die 20, and its base portion 31a. It has been planted in.

As shown in FIG. 5, the lower mold 10 and the upper mold 30 are lower heats attached to a movable plate (not shown) or a fixed plate (not shown) of a press which is relatively movable in the vertical direction. It is fixed to the plate 60 and the upper heating plate 70, respectively, and the upper die 30 and the middle die 20 can be matched with each other by a guide pin (not shown) provided on the upper die 30.

Therefore, when the lower mold 10 and the upper mold 30 are closed and the middle mold 20 and the upper mold 30 are matched, the upper mold 30
The core body 31 provided in the core body 21 is fitted into the cylinder portion 21 of the middle-sized body 20, and a cylindrical cavity 21a forming the peripheral wall 2b of the bottomed cylinder body 2 can be formed in the gap between the cylinder portion 21 and the core body 31. ing.

Next, a method of manufacturing the bottomed cylindrical body 2 using the molding die 100 described above will be described. First, an unvulcanized rubber sheet 1 having a thickness substantially equivalent to a rubber material for forming a large number of bottomed cylinders 2 is formed in advance with a roll machine or the like (not shown) to a predetermined size. To do.

Next, as shown in FIG. 3, the unvulcanized rubber sheet 1 is provided on the upper surface 10a of the lower mold 10 with a large number of partition grooves 1.
Place it so as to cover 1 including it. After that, the middle die 20 is guided through the unvulcanized rubber sheet 1 onto the lower die 10 with the guide pin 40.
Place along the line.

Next, the upper die 30 is placed above the middle die 20 with the compression coil 50 interposed therebetween.
The lower surface 30a of 0 is supported at a predetermined interval.

Next, the lower die 10 is lifted up together with the lower heating plate 60 by pressing pressure as shown by an arrow, and the upper die 3
0 contacts the upper heating plate 70, and then, as shown in FIG. 4, first, the lower mold 10 and the middle mold 20 are matched with each other via the protruding portion 1b. And most of the unvulcanized rubber sheet 1a
Is pressed and supplied to the tubular portion 21 of the middle-sized die 20 via the compression coil spring 50. Subsequently, the compression coil spring 50 presses the lower mold 10 and the middle mold 20, and finally the middle mold 20 and the upper mold 30 are matched with each other as shown in FIG.

At this time, most of the unvulcanized rubber sheet 1 supplied to the tubular portion 21 of the middle die 20 is pressed by the core body 31 into the gap cavity 21a between the tubular portion 21 and the core body 31 of the middle die 20. Is filled.

Preferably, a core body 31 is provided on the lower surface of the upper mold 30.
A reservoir groove 30c is formed around the outer periphery of the base 31a for storing excess rubber material. The contour of the base portion 31a is formed to be substantially the same as the inner circumference of the tubular portion 21, and the burr formed in the reservoir groove 30c can be completely separated from the molded product.

By closing the lower mold 10 with respect to the upper mold 30 and performing vulcanization molding, as shown in FIG.
A connected molded product 5 in which the bottomed tubular body 2 is connected by a sheet-shaped burr rubber 3 through a partition mountain 4 formed corresponding to a number of partition grooves 11 is molded.

Thereafter, by separating the middle mold 20 and the lower mold 10 from the upper mold 30, the connected molded product 5 can be left in an engaged state with the middle mold 20, and the remaining connected molded product can be left. 5 can be easily removed from the middle mold 20.

Finally, only the bottomed cylindrical body 2 of the obtained connected molded product 5 could be easily torn off from the sheet-shaped burr 3 along the inner periphery of the endlessly formed partition mountain 4. . The bottomed tubular body 2 thus obtained can be manufactured neatly without burrs and can be used as it is as a heat conductive rubber cap.

[0029]

EFFECTS OF THE INVENTION According to the present invention, there is no possibility that burrs will remain on the bottomed tubular body obtained, and burrs will not easily remain on the mold, so cleaning of the mold is not necessary for each molding. Become.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part for explaining a molding die.

FIG. 2 is a plan view of the lower mold in FIG.

FIG. 3 is a cross-sectional view of essential parts showing a state where an unvulcanized rubber sheet having a predetermined size is placed on the lower mold of the molding die in FIG.

4 is a cross-sectional view of essential parts showing a state in which a middle mold has been fitted to the lower mold in FIG.

5 is a cross-sectional view of essential parts showing a state in which the upper die and the lower die in FIG. 3 are closed with an intermediate die interposed therebetween.

FIG. 6 is a plan view of a connected molded product that is molded using the molding die in FIG.

7 is a sectional view taken along line XX of FIG.

FIG. 8 is a perspective view of a bottomed cylinder obtained by using a molding die.

[Explanation of symbols]

 1: Unvulcanized rubber sheet 2: Bottomed cylinder 3: Burr rubber 4: Partition mountain 5: Connected molded product 10: Lower mold 11: Partition groove 20: Middle mold 21: Cylindrical part 21a: Gap cavity 30: Upper mold 31: Core 100: Molding die

Claims (2)

[Claims] 1. A method of manufacturing a bottomed cylindrical body made of rubber; a step of forming an unvulcanized rubber sheet having a predetermined size; and forming a back surface of the bottom of each of the plurality of bottomed cylindrical bodies. A step of coating the unvulcanized rubber sheet on the upper surface of a lower mold having an upper surface with a plurality of partition grooves partitioning endlessly for each bottom, including the plurality of partition grooves. A plurality of vertically penetrating cylindrical portions having inner peripheries substantially corresponding to respective inner contours of the plurality of partition grooves for forming respective outer peripheral surfaces of the plurality of bottomed cylindrical bodies; The unvulcanized rubber sheet placed on the upper surface of the lower mold by aligning a middle mold disposed above the lower mold, which is relatively separable from the lower mold, with the lower mold. And a step of supplying most of the pressure to the cylindrical portion of the middle mold; disposed above the middle mold so as to be relatively separable from the middle mold and the lower mold. The upper die is substantially closed with respect to the lower die, and a plurality of core bodies forming the inner surface of the bottomed cylindrical body protruding downward from the lower surface of the upper die are provided in the middle die. A bottomed cylinder, which is fitted into a cylindrical portion and is filled with the core body by pressing most of the unvulcanized rubber sheet supplied to the cylindrical portion of the middle mold into a cavity between the cylindrical portion and the core body. A step of vulcanizing and molding a body into a connected molded product that is connected to each other with a sheet-shaped burr rubber through partition mountains formed corresponding to the plurality of partition grooves; and the bottomed cylindrical body of the connected molded product. And a step of tearing off the sheet-shaped burr rubber. 2. A molding die used in a method of manufacturing a bottomed cylindrical body made of rubber, which is endlessly partitioned to form a bottom surface of a large number of bottomed cylindrical bodies substantially on the top surface. A lower die having a large number of dividing grooves: It is relatively separable from the lower die having a plurality of vertically penetrating cylindrical portions for forming the outer peripheral surfaces of the respective bottomed cylindrical bodies. A middle mold disposed above the lower mold; and an upper mold disposed above the middle mold so as to be relatively separable from the middle mold; when the upper mold and the lower mold are closed , The upper die projects downward from the lower surface of the upper die for forming the inner surface of the bottomed cylindrical body, and is fitted into the plurality of cylindrical cavities provided in the middle die. In addition to the core body, the inner peripheral edges of the lower ends of the plurality of cylindrical cavities provided in the middle mold are close to the inner sides of the partition grooves of the lower mold. A molding die used in a method for manufacturing a bottomed cylindrical body made of rubber, which is provided so as to come into contact with each other in a contact state or an adjacent state.