JPS6140121A - Forming method of seal ring - Google Patents

Abstract

PURPOSE:To obtain a product easy to remove flashes because they are thin and constant in thickness and high in quality by applying friction reducing lubricant to the mating surfaces of both mold blocks and forming compression seal rings. CONSTITUTION:Top and bottom forces 1, 2 are fixed to respective press holders 3, 3 and approach and depart each other. Cavities 4 corresponding to seal rings are provided on the mating surface 1a, 2a of each force 1, 2. Friction reducing lubricant W is applied to the mating surface 1a, 2a of each force 1, 2. Then, a block or a plate type substance 5 of unvulcanized rubber is inserted between the forces 1, 2. When both forces 1, 2 are compressed by a press in the arrow direction F, F so that they approach each other, the unvulcanized rubber plate type substance 5 is deformed (rolled) flatly and moved and charged in the cavity 4. When silicone rubber is used as rubber material, silicone oil can be applied as lubricant W and any bad influence is not given to the compound of silicone rubber.

Description

[Detailed description of the invention] The present invention relates to a seal ring molding method.

Conventionally, after unvulcanized rubber is charged between molds, the unvulcanized rubber is pressurized while the molds are brought close to each other and deformed into a flat shape (rolling).
In order to mold the seal ring by moving and filling the seal ring into the cavity, the pressing force applied to the mold by the press was required to be extremely large. For example, in the conventional molding method, there is
The relationship is as shown by the broken line A in FIG. Generally, it is desirable that the thickness of the seal ring be about 0.03 m, but in that case, as is clear from the broken line A in Figure 5, the thickness of the seal ring will be 900 kg.
A large surface pressure of /- or more must be applied by a press, and a significantly large press must be used.

The above broken line A changes depending on the type of rubber, but in some cases it may be possible to roll the sheet to a sheet thickness of only 0.1M when a surface pressure of 880 kg/cd is applied. This is because vulcanization is accelerated during rolling so that the rubber becomes an incompressible solid and resists the press pressure.

As described above, the conventional seal ring forming method has the drawback that the pressurizing force is insufficient in a normal press and a particularly large press is required, and it is difficult to control the thickness of the seal, sometimes reaching a thickness of 0.05+n or more. As a result, there was a problem of quality defects in the seal ring.

As a countermeasure, a method has been adopted in which the material is manually inserted into the mold cavity in the form of a rubber ring or string and then pressurized with a press, but this method has the fatal drawback of being difficult to automate.

The object of the present invention is to eliminate these conventional drawbacks and to roll-form a sheet to a desired small thickness and sheet thickness using a small pressing force.

Hereinafter, the present invention will be explained in detail based on the illustrated embodiment. In FIGS. 1 to 4, 1.2 are upper and lower molds, respectively, which are fixed to a press mounting plate 3.3 and close to each other. To separate. A cavity 4 corresponding to a seal ring is recessed in the mating surfaces 1a and 2a of both molds 1.2.

In the seal ring molding method according to the present invention, as shown in FIG.
Apply to 2a. Next, a lump or plate-like body 5 of unvulcanized rubber
is charged between both molds 1 and 2. For example, in FIG. 2, the plate-like body 5 is placed approximately in the center of nine cavities 4.

Next, both molds 1. are pressed in the direction of arrows F and F in FIG. When pressurizing molds 2 in the direction of approaching each other, both molds 1
, 2, the unvulcanized rubber plate-like body 5 is flattened (rolled) and moved and filled into the cavity 4, resulting in the state shown in FIG. 4.

For example, when silicone rubber is used as the rubber material mentioned above, silicone oil can be used as the lubricant W, and this silicone oil does not have any adverse effect on the silicone rubber condensation land. In addition, it is desirable that the lubricant W not have an adverse effect on the unvulcanized compound. As shown in Fig. 1, the lubricant W is sprayed into fine particles on the mating surface 1a,
It is desirable to apply by spraying onto 2a.

The solid line B shown in FIG. 5 represents the surface pressure p (k+r/cnl) applied to unvulcanized nitrile rubber (on the other hand, when silicone oil is used as the lubricant W), and /z
These are actual measurement results showing the relationship between T (mu) (sheet thickness) and T (mu). According to this, the effect of the lubricant W is clearly visible.

Generally, the thickness of ring seals such as O-rings is 0.03m.
m, it is easy to remove and the quality of the product is also good. From solid line B in Figure 5, p = 250kg/Ct
It can be seen that the desired T=0.03 can be achieved at a low pressure of &. Further, if p = 400 kg/aj, the Paris thickness T is further reduced and a thickness T = 0.02 + w + m can be obtained.

As shown in Fig. 3, when pressing the unvulcanized rubber plate 5 while bringing the molds 1 and 2 close together, at least one of the molds 1.degree. , which is preferable because rolling can be performed with a smaller surface pressure p.

Generally, both molds 1 and 2 are heated to perform molding and vulcanization at the same time.

In addition to charging the unvulcanized rubber in the form of a plate 5 between the two molds 1.2, the same effect can be obtained by charging the unvulcanized rubber in the form of a block. When the diameter is increased, similar effects can be obtained by making a preform of unvulcanized rubber in advance to approximate the shape of the final product and pressurizing it. Furthermore, it goes without saying that the lubricant W can be selected from various types depending on the rubber material, but it is preferable to use materials and components that have little effect on the unvulcanized rubber compound.

As described above, the present invention provides a seal ring that, after unvulcanized rubber is charged between the molds, is pressurized by both molds to flatten the unvulcanized rubber while moving and filling it into the cavity. In the molding method, a friction-reducing lubricant is applied to the mating surfaces of the two molds, and then the unvulcanized rubber is pressurized by both molds, so the lubricant is This significantly reduces the frictional force between the mold mating surface and the unvulcanized rubber, allowing the rubber to move smoothly into the cavity. Therefore, the following effects can be obtained.

(a) Simply insert a lump or plate of unvulcanized rubber between both molds, and easily roll it with a small pressing force.
Can be moved and filled into the cavity. (b) A small press can be used satisfactorily.

(c) The thickness of the paris is thin and constant, making it easy to remove the paris.
Moreover, a stable product (seal ring) of high quality can be obtained. (d) Even seal rings with relatively large diameters can be molded. (e) Pre-forming becomes easy.

[Brief explanation of the drawing]

1 to 4 are diagrams for explaining an embodiment of the present invention in the order of steps, in which FIG. 1 is a partially sectional front view, FIG. 2 is a plan view of the main part, and FIG. 3 is a sectional view. The front view and FIG. 4 are enlarged sectional views when rolling is completed. FIG. 5 is a graph comparing the seal ring molding method according to the present invention with the conventional molding method, and is a graph of actual measurement results showing the relationship between the surface pressure applied to the rubber and the sheet thickness (paris thickness). be. 1.2...mold, la, 2a...mating surface, 4...
・Cavity, W...Lubricant. Patent applicant Dainichi Nippon Electric Cable Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. Seal ring molding in which unvulcanized rubber is charged between molds, and then the unvulcanized rubber is pressed by both molds to flatten it and move it into a cavity and fill it. A seal ring molding method comprising: applying a friction-reducing lubricant to the mating surfaces of the two molds, and then pressurizing the unvulcanized rubber with the two molds.