JP2584659B2 - Molding method of diaphragm with base cloth - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for forming a diaphragm by laminating a base fabric for reinforcing rubber.

[Prior Art] As shown in FIG. 8, a general diaphragm has, for example, a three-layer structure in which a reinforcing base cloth a is interposed and rubbers b and c are laminated above and below the base cloth a. Aperture part d
Is formed by hot press molding. Symbol e is a bead for attachment.

In order to manufacture such a diaphragm with a base cloth, as shown in FIG. 9, a molding base f in which a fiber sheet is sandwiched between unvulcanized rubber sheets is hot-pressed with a female mold and a male mold. Then, a large number of pieces were taken (six pieces in the figure).

[Problems to be Solved by the Invention] By the way, in the case of such a diaphragm with a base cloth,
For example, when a deep drawing is performed as shown by a two-dot chain line in FIG. 8 to close to the limit of the elongation of the base cloth a, multiple pieces shown in FIG. It is necessary to use a molding substrate. However, if the same number of molded base materials cut in this way are set on the female mold as in the conventional multi-cavity, this setting takes time,
There is a difference in quality between the first and the last placed on the heated female mold. For this reason, the number of molds that can be molded simultaneously in one molding is reduced, the molding efficiency is reduced, and the product cost is significantly increased. Further, deep drawing beyond the elongation limit of the base cloth a was impossible.

Therefore, an object of the present invention is to provide a molding method capable of taking a large number of such deep-drawn diaphragms with a base cloth.

[Means for Solving the Problems] In order to solve the above problems, a method for forming a diaphragm according to the present invention is characterized in that, in a process of hot press forming, when a base fabric reaches an elongation limit or close to the limit, the periphery of a formed portion Is cut from the molding base material, then further deep drawn and clamped, and vulcanized at a predetermined temperature and time.

According to the method of the present invention, when the base cloth reaches or closes to the elongation limit, the periphery of the formed part is cut from the forming base material. Moves so as to be drawn into the female mold as it is with the unvulcanized rubber of the molded portion without extending beyond the limit. Therefore, when the mold is clamped and vulcanized at a predetermined temperature and for a predetermined time, a reinforced base fabric layer is formed in the rubber layer even in deep drawing beyond the elongation limit of the base fabric.

In addition, since what is initially set on the mold is a sheet-shaped molding base made of a large number of pieces, the setting is completed once.

[Embodiment] FIGS. 1 to 6 show an embodiment of the present invention. FIG. 1 is a cross-sectional view showing an outline of molding, and a plurality of molding recesses 2 are provided in a female mold 1 which has been heated to about 200 ° C. in advance. The molded concave portion 2 forms a circular concave portion as viewed from above. An annular concave portion 3 for forming a bead is formed on the mating surface of the molded concave portion 2. Further, an annular groove 4 is formed around the concave portion 3 and accommodates a ring-shaped slide 5 and a spring 6 for urging the slide 5 upward.

On the other hand, the male mold 7 is also provided with a plurality of cylindrical molding projections 8 which can be fitted into the molding recesses 2 and the recesses 3 on the mating surface thereof.
An annular concave portion 9 is formed at a position corresponding to. A ring-shaped cutter 10 is provided at a position corresponding to the slide 5 so as to surround the forming protrusion 8. cutter
10 has a height of dimension l ₁ from the base of the male mold 7 and has a cutter
A difference of dimension l ₂ is formed between the cutting edge 10 and the top of the forming projection 8. This dimension l ₂ coincides with the pushing amount of the forming projection 8 when the elongation limit of the fiber sheet described later is reached.

Rollers 1 on both sides of female mold 1
1, 12 and 13, 14 are provided, and these rollers 11 to 14 are provided.
The reinforcing fiber sheet 16 wound between the rolls 15 is passed from left to right in the figure.

Therefore, when setting the molding material first, the female mold 1
The unvulcanized rubber sheet 17 is placed thereon, and then the fiber sheet 16 is pulled out and stacked on the fiber sheet 16 between the rollers 11 to 14. Further, an unvulcanized rubber sheet 18 is stacked on the fiber sheet 16. Thereby, the molding base material 19 having a three-layer laminated structure is formed.
Is completed. However, unvulcanized rubber sheets 17 and 18
Of these, any one of them may be omitted.

Next, when the male mold 7 is moved downward and the molding base 19 is pressed, the molding base 19 is pushed into the molding recess 2 by the molding projection 8 as shown in FIG. when pushing amount of the dimension l ₂ of the fiber sheet 16 reaches the elongation limit, the cutter 10 contacts the molding substrate 19 around the forming section (i.e., the portion located on a slide 5). At this time, the re-deep portion of the molding base material 19 has a dimension l ₁ from the bottom of the molding concave portion 2.
In the position.

Then, when the molding projection 8 is further pushed into the molding recess 2, the cutter 10 pushes the slide 5 into the groove 4 against the spring 6 while sandwiching the molding base 19. 19, a cut debris 20 is formed between the cutter 10 and the slide 5, and at the same time, rubber layers 21, 23 and a base cloth 22 cut from the molding base material 19 are formed on the molding portion.
Is formed.

As a result, the base cloth 22 of the molded portion can be moved into the molded concave portion 2 without being stretched beyond the elongation limit.
The base cloth 22 is drawn into the molding recess 2 with the elongation of the rubber layers 21 and 23, and the state shown in FIG. 3 is obtained. At this time, beads 24 are formed in the recesses 3 and 9 by the rubber layers 21 and 23. When the mold is clamped in this state and maintained for a predetermined time and at a predetermined temperature (for example, about 20 minutes, about 200 ° C.), the rubber layers 21 and 23 are vulcanized while the base cloth 22 is integrated.

Then, after a predetermined time, when the mold is opened and the male mold 7 is moved upward, the cut debris 20 is discharged from the groove 4 by the slide 5 which is returned by the spring 6 as shown in FIG. FIG. 5 shows a state immediately after the mold is opened. Since six diaphragms 25 are simultaneously obtained in this embodiment by one press molding, these molded articles are demolded one by one. FIG. 6 shows a diaphragm 25 thus constructed.
This diaphragm 25 has sufficient strength because the base fabric 22 within the elongation limit is integrated inside despite the drawn portion 26 being deep drawn, However, sufficient durability can be obtained.

FIG. 7 shows a state of a part of the molded product immediately after molding by another cutting method and opening the mold.
That is, by leaving a part of the periphery of the diaphragm 25 without cutting it, the adjacent diaphragms 25 are connected by the joint part 27. By doing so, a large number of diaphragms 25 can be taken out at one time at the time of demolding after vulcanization is completed, and then the joint portion 27 can be cut off, so that the demolding operation can be performed quickly.

[Effects of the Invention] According to the method of the present invention, a large number of pieces can be formed even in the case of a deep-drawing diaphragm with a base cloth, so that a large number of molding substrates can be set in one step at a time. Became. Therefore, it is suitable for mass production, and the quality of the molded product can be stabilized, and the cost can be reduced.

[Brief description of the drawings]

1 to 7 show an embodiment, FIG. 1 is a schematic cross-sectional view of a molding system, FIGS. 2 to 4 are cross-sectional views of main parts in a molding process, and FIG. 5 is molding immediately after the mold is opened. FIG. 6 is a perspective view showing a state, and FIG. 6 is a perspective view of a molded product. FIG. 7 is a partially enlarged plan view showing a molding state immediately after the mold is opened after molding by another cutting method. FIG. 8 is a sectional view of a conventional product, and FIG.
The figure is a perspective view showing the multi-cavity molding state. (Explanation of reference numerals) 1... Female mold, 2... Molded recess, 7... Male mold, 8... Molded protrusion, 9... Molded base material, 10. 18 ... Unvulcanized rubber sheet, 22 ... Base cloth, 25 ...
... a diaphragm.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 105: 24 B29L 9:00 31:26

Claims (1)

(57) [Claims] 1. A method of forming a diaphragm with a base cloth, comprising the following steps a to e. a. A step of placing a molded substrate in which a fiber sheet and an unvulcanized rubber sheet are stacked on a female mold. b. A step of pushing the forming base material into the forming recess of the female mold to or near the elongation limit of the fiber sheet by the male forming protrusion. (c) a step of cutting the periphery of the molded portion from the molding base material when the fiber sheet has reached or is near the elongation limit. (d) A step of further pressing the cut molding base material into the female molding concave portion by the male molding projection to deeply draw the molded portion and clamp the mold. e. vulcanizing the unvulcanized rubber at a predetermined temperature for a predetermined time after clamping.