JPH01280514A - Molding method of diaphragm with base cloth - Google Patents

Abstract

PURPOSE:To enable multiple-shot molding of deep drawn diaphragms with base cloth, by a method wherein when the base cloth arrives at elongation limit or its vicinity in a course of hot press molding, the circumference of a molding part is cut off from a molding base material, a mold is clamped by performing deep drawing further and vulcanized. CONSTITUTION:A molding base material 19 obtained by piling up a fiber sheet 16 and unvulcanized rubber sheets 17, 18 is put on a female mold 1. When the molding base material 19 is pressed by moving a male mold 7 downward, the molding base material 19 is pressed into a molding recessed part 2 with a molding protrusion 8, and when a quantity of pressing-in of the molding protrusion 8 is dimensions l2, the fiber sheet 16 arrives at its elongation limit and a cutter comes into contact with the jolding base material 19 at the circumference of a molding part. When the molding protrusion 8 is pressed into the molding recessed part 2 further, since the cutter 10 presses a slide 5 into a groove 4 against a spring 6 while placing the molding base material 19 between the cutter 10 and the slide 5, the circumference of the molding part is cut off from the molding base material 19. Base cloth of the molding part is not elongated by exceeding the elongation limit and moved within the molding recessed part 2. When mold clamping is performed under this state and fixed time and fixed temperature are kept on, a rubber layer is vulcanized as the base cloth is integrated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for molding a diaphragm formed by laminating a reinforcing base fabric on rubber.

[Prior Art] As shown in Fig. 8, a typical diaphragm has a three-layer structure in which, for example, a reinforcing base fabric (a) is placed in the middle, and rubber (b) and (c) are laminated above and below the base fabric (a). The constricted portion d is formed by hot press molding. The symbol e is a beat for attachment.

In order to manufacture such a diaphragm with a base fabric, the ninth
As shown in the figure, a molding base material f with a fiber sheet sandwiched between unvulcanized rubber sheets is hot press molded using a female die and a male die.
A large number of pieces (six pieces in the figure) were taken.

[Problems to be Solved by the Invention] In the case of such a diaphragm with a base fabric, for example, when deep drawing is performed to draw the base fabric a close to its elongation limit as shown by the two-dot chain line in FIG. In this case, it is not possible to produce a large number of pieces as shown in FIG. 9, and it is necessary to use a molding base material that is cut into pieces in advance. However, if the same number of molding base materials cut in this way are set on the female mold as in the conventional multi-piece mold, this setting will take time, so There is a difference in quality between the original and the one placed later. For this reason, the number of moldings that can be molded simultaneously in one molding cycle is reduced, the molding efficiency is lowered, and the product cost is significantly increased. Also, base fabric a
Deep drawing beyond the elongation limit was impossible.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a molding method that can produce a large number of such deep-drawn diaphragms with base fabric.

[Means for Solving the Problems] In order to solve the above problems, the method for forming a diaphragm according to the present invention provides a method for forming a diaphragm in which, in the process of hot press molding, when the base fabric reaches or near its elongation limit, is cut from the molding base material, then further deep drawn and mold clamped,
It is characterized by vulcanization at a predetermined temperature and time.

[Operation of the invention] According to the method of the present invention, when the base fabric reaches or near its elongation limit, the periphery of the molded part is cut from the molded base material. The rubber does not stretch beyond its limit and moves as it is drawn into the female mold together with the unvulcanized rubber in the molding section. Then, when the mold is clamped and vulcanized at a predetermined temperature and time, a reinforcing base fabric layer is formed in the rubber layer even when deep drawing exceeds the elongation limit of the base fabric.

Moreover, since a sheet-like molding base material made up of many pieces is initially set on the mold, the setting can be completed in one time.

[Example] An embodiment of the present invention is shown in FIGS. 1 to 6.

Figure 1 is a cross-sectional view showing the outline of molding, and approximately 200
A plurality of molding recesses 2 are provided in the female mold 1 heated to about .degree. The molded recess 2 is circular in top view. An annular recess 3 for molding the beat is formed on the mating surface of the molding recess 2. Further, an annular groove 4 is formed around the recess 3, and a ring-shaped slide 5 and a spring 6 for biasing the slide upward are accommodated in this groove.

On the other hand, a plurality of cylindrical molding protrusions 8 that can fit into the molding recess 2 are also formed on the male mold 7, and an annular recess 9 is formed on the mating surface at a position corresponding to the recess 3. . Also,
A ring-shaped cutter 10 is provided protrudingly surrounding the molding projection 8 at a position corresponding to the slide 5. Cutter 1
0 has a height of 100 mm from the base of the male die 7, and a 100 mm difference is formed between the cutting edge of the cutter 10 and the top of the molding protrusion 8. This dimension statement 2 corresponds to the pushing amount of the molding protrusion 8 when the fiber sheet reaches its elongation limit, which will be described later.

On both the left and right sides of the female mold 1, there are rollers 11 arranged in pairs above and below.
．． 12 and 13.14 are provided, and this roller 11
A reinforcing fiber sheet 16 wound around a roll 15 is passed between the spaces 14 to 14 from left to right in the figure.

Therefore, when the molding material is first set, a young unvulcanized rubber sheet 17 is placed on the female die 1, and then the fiber sheet 16 is pulled out and stacked on top of it so as to pass between the rollers 11 to 14. Furthermore, an unvulcanized rubber sheet 18 is placed on top of this fiber sheet 16. This completes the setting of the molded base material 19 having a three-layer laminated structure. However, any one of the unvulcanized rubber sheets 17 and 18 may be omitted.

Next, when the male mold 7 is moved downward and the molded base material 19 is pressed, the molded base material 19 is pushed into the molded recess 2 by the molded protrusion 8, and the molded base material 19 is pushed into the molded recess 2 by the molded protrusion 8, as shown in FIG.
When the pushing amount is 2, the fiber sheet 16 reaches its elongation limit, and the cutter 10 cuts the molded base material 19 around the molded part.
(that is, the part located above the slide 5). At this time, the deep part of the molded base material 19 is located at a position of 100 mm from the bottom of the molded recess 2.

Therefore, when the molding protrusion 8 is further pushed into the molding recess 2, the cutter 10 moves into the slide 5 while sandwiching the molding base material 19.
is pushed into the groove 4 against the spring 6, so the periphery of the molded part is cut from the molded base material 19, and cut waste 20
is formed between the cutter 10 and the slide 5, and at the same time a rubber layer 21 cut from the molded base material 1.9 is formed in the molded part.
．． A three-layer structure consisting of the base fabric 23 and the base fabric 22 is formed.

As a result, the base fabric 22 of the molded part can be moved into the molding recess 2 without being stretched beyond the stretching limit.
The base fabric 22 is drawn into the molding recess 2 as the rubber layer 21.23 stretches, resulting in the state shown in FIG. At this time, the bead 2 is formed in the concave portion 3 and the fourth portion 9 by the rubber layers 21 and 23.
4 is formed. If the mold is clamped in this state and maintained at a predetermined temperature for a predetermined time (for example, about 200 degrees Celsius for about 20 minutes),
The rubber layers 21 and 23 are vulcanized while the base fabric 22 remains integrated.

Then, after a predetermined time, when the mold is opened and the male mold 7 is moved upward, the cut waste 20 is discharged from the groove 4 by the slide 5 which is returned by the spring 6, as shown in FIG. Figure 5 shows the state immediately after opening the mold, -
In this embodiment as well, six diaphragms 25 are obtained at the same time by multiple press moldings, so these molded products are demolded one by one. FIG. 6 shows the structure of the diaphragm 25 formed in this way, and this diaphragm 25 has a constriction part 26.
Although it is deep-drawn, the base fabric 22 within the elongation limit is integrated inside, so it has sufficient strength and has sufficient durability for subsequent use.

FIG. 7 shows the state of a part of a molded product immediately after molding by another cutting method and opening the mold. That is, by leaving a part of the diaphragm 25 without cutting the entire circumference, the adjacent diaphragm 25
are connected by a joint portion 27. In this way, when demolding after completion of vulcanization, a large number of diaphragms 25 can be taken out at once and then the joint portions 27 can be separated, so that the demolding work can be done quickly.

[Effects of the Invention] According to the method of the present invention, even deep-drawn diaphragms with base fabric can be molded into multiple pieces, so the molding base material can be set in multiple pieces in one process. It became so. Therefore, it is suitable for mass production, and it is possible to stabilize the quality of molded products and reduce costs.

[Brief explanation of the drawing]

Figures 1 to 7 show examples, Figure 1 is a schematic sectional view of the molding system, Figures 2 to 4 are sectional views of important parts in the molding process, and Figure 5 is the molding immediately after opening the mold. A perspective view showing the state, FIG. 6 is a perspective view of the molded product. FIG. 7 is a partially enlarged plan view showing the molded state immediately after the mold is opened after molding by another cutting method. Figure 8 is a cross-sectional view of the conventional product, Figure 9
The figure is a perspective view showing the multi-cavity molding state. (Explanation of symbols) 1... Female mold, 2... Molding recess, 7... Male mold, 8...
... Molding protrusion, 9... Molding base material, 10... Cutter, 16... Fiber sheet, 17.18... Unvulcanized rubber sheet, 22... Base fabric, 25... diaphragm. Patent record applicant Toyodenso Co., Ltd. Agent Patent attorney Kiyomitsu Komatsu Figure 4 Figure 5 Figure 8

Claims (1)

[Scope of Claims] A method for forming a diaphragm with a base fabric, characterized by comprising the following steps a to e. a. A process of placing a molding base material consisting of a fiber sheet and an unvulcanized rubber sheet on top of a female mold. b. A step of pushing the molding base material into the molding recess of the female mold by the molding protrusion of the male mold to the elongation limit of the fiber sheet or close to it. c. A step of cutting the area around the molded part from the molded base material when the fiber sheet reaches its elongation limit or near it. d. After that, the cut molding base material is further pushed into the molding recess of the female mold by the molding protrusion of the male mold, and the molding part is deep drawn and the mold is clamped. e. A step of vulcanizing the unvulcanized rubber at a predetermined temperature for a predetermined time after mold clamping.