JPH04308707A - Molded product, its molding method and mold - Google Patents

Abstract

PURPOSE:To enable fitting of molds on a plane surface, by a method wherein a plurality of stepped grooves are provided along a circumferential direction on the fringe of a side where a chamfered part of an outer circumferential fitting pad is provided, in a molded product such as an oil seal where a tapered and chamfered part is provided on the fringe of the outer circumferential fitting part. CONSTITUTION:An oil seal 1 possesses a rubbery elastic body 3 which is an annular member having almost a U-shaped section and possesses a reinforcing ring 2 having an L-shaped section for its core metal, a cylindrical outer circumferential fitting part 4 fitted into an inner circumference of the other mounting part and a sealing lip 6 which is extended by inclining toward the tip in an axial direction from an end of the inside diameter of a flange part 5 facing the inside of the outer circumferential fitting part 4. An end surface of the outer circumferential fitting part 4 is provided with a tapered and chamfered part 8. On this occasion, a plurality of stepped grooves 9 are arranged on the fringe of the outer circumferential fitting part 4 in a circumferential direction at equal intervals by separating from each other so that the grooves 9 cross the tapered and chamfered part 8. With this construction, since a specific mold and the other mold are ground each other on a plane surface, a deviation of the molds at the tapered and chamfered part is eliminated and moldability is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various molded products such as oil seals, methods of molding the same, and molds.

0002

2. Description of the Related Art A conventional molded product of this type is an oil seal as shown in FIG. 3, for example. That is,
This oil seal 100 has a fitting hole 1 of a mating member.
An outer periphery fitting portion 102 is provided that fits tightly into the inner periphery of the 01. Chamfered portions 103 are provided on both end edges of this outer circumferential fitting portion 102, and this chamfered portion 1
03, for example, absorbs the build-up during fitting to prevent rubber tearing and the like.

[0003] When the total width C of the oil seal is small, for example, 4 mm or less, in order to make the effective fitting width B that closely fits into the fitting hole 101 as large as possible, the chamfered portion 1 is
03 was tapered.

0004

However, in the case of the above-mentioned prior art, the molding is performed as shown in FIG.
Although this is performed using molds that are divided into the first to third molds 104, 105, and 106, the sliding surface S1 of the second mold 105 and the first mold 104 has a tapered chamfered portion. 104 and the effective fitting surface, burrs are likely to appear on this sliding surface, and problems such as mold misalignment are likely to occur.

On the other hand, as shown in FIG. 5, the standard size oil seal, which has a general width of about 5 to 15 mm, can have a large effective fitting width B, so the outer circumferential chamfered portion 1
The shape of 08 is a stepped shape. If you do this,
As shown in FIG. 6, the first mold 104 and the second mold 105 can be rubbed together on the plane S2 during molding.
This is advantageous because deformation or the like does not occur at the end position of the tapered chamfered portion 104 as described above. In addition, since there is a gap A between the second mold 105 and the molded product 107, and the molded product 107 reliably remains on the second mold 105, it has good mold releasability and operability. It's good.

[0006] Therefore, as shown in FIG. 7, even in the case where a tapered chamfered portion 103 is provided, it is conceivable that the first mold 104 and the second mold 105 are constructed so that they are flat-faced. However, with such a planar sliding configuration, the tapered convex portion 109 tends to sag,
This may cause molding defects.

The present invention has been made to solve the problems of the prior art described above, and its purpose is to:
A molded product that enables sliding on the flat surface of a mold while ensuring the functionally necessary effective fitting width by combining the good moldability of flat surface sliding with a chamfered outer circumferential shape, and its molding method. Our goal is to provide molds.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes an outer circumferential fitting portion that is closely fitted to the inner circumference of the fitting hole of a mating member, and In a molded product having a tapered chamfered portion on the edge of the outer circumferential fitting portion, the edge of the outer circumferential fitting portion on the side where the tapered chamfered portion is provided,
It is characterized in that a plurality of stepped grooves are provided along the circumferential direction so as to cross the tapered chamfered portion and are partially spaced apart from each other.

[0009] This molded product is provided with an outer circumferential fitting portion that is fitted into the inner periphery of a fitting hole of a mating member, and a tapered chamfered portion is formed on the edge of the outer circumferential fitting portion. In the molding method, a stepped groove is formed along the tapered chamfer on the edge of the outer peripheral fitting part along with the tapered chamfer so as to be partially spaced along the circumferential direction. shall be.

[0010] This molded product is provided with an outer periphery fitting portion that is fitted into the inner periphery of a fitting hole of a mating member, and includes a plurality of dies that can be opened and closed with each other, and the plurality of dies are In a mold in which a specific mold is provided with an annular wall for forming the outer circumferential fitting portion, a tapered convexity is formed along the circumferential direction on an edge of the inner circumference of the annular wall of the specific mold. a plurality of stepped convex portions spaced apart in the circumferential direction so as to cross the tapered convex portion, and further, an annular wall end surface of the specific mold is joined to a flat surface of another mold. It is characterized by being

[0011]

[Operation] In the present invention, the stepped convex portion of the annular wall of a specific mold among the plurality of molds bites into the outer peripheral fitting portion of the molded product, and the molded product is identified when the mold is opened. The mold is held in the mold and the molded product remains in the specific mold.

Furthermore, since the width of the effective fitting surface of the outer peripheral fitting portion is basically determined by the width of the tapered chamfered portion, a sufficient width of the effective fitting surface can be ensured.

Furthermore, by rubbing a specific mold and another mold together on a plane, there is no mold displacement at the tapered chamfered portion, and moldability is excellent.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the illustrated embodiments. FIG. 1 shows a conventional oil seal as a molded product according to an embodiment of the present invention. This oil seal 1 is a ring member having a substantially U-shaped cross section, and is formed by molding a rubber-like elastic body 3 into a predetermined shape using a reinforcing ring 2 having an L-shaped cross section as a core metal and a molding material, and is attached to a mating member (not shown). It is provided with a cylindrical outer circumferential fitting part 4 that is fitted to the inner circumference, and an inward flange part 5 extending inward from the atmosphere side edge of the outer circumferential fitting part 4 extends from the inner diameter end to the tip in the axial direction. It is configured to include a seal lip 6 made only of a rubber-like elastic body and extending in an inclined manner so that the diameter thereof gradually becomes smaller.

A tapered chamfered portion 8 is provided at the edge of this outer circumferential fitting portion 4 . The end of this tapered chamfered portion 8 forms a boundary line with the effective fitting surface 7. A plurality of stepped grooves 9 are spaced apart from each other and equally distributed in the circumferential direction on the edge of the outer circumferential fitting surface 4. This stepped groove 9 is formed so as to cross the tapered chamfered part 8, and in this embodiment, it is provided at the O end edge on the sealed fluid side of the effective fitting surface 7 of the outer circumferential fitting part 4, and is circular. They are evenly distributed in the circumferential direction. Then, the inner end position of the stepped groove 9 enters into the effective fitting surface 7 side.

FIGS. 2 and 3 show a mold for molding the oil seal 1, and this mold 10 has the following features:
Multiple molds that can be opened and closed with each other, in this example upper, middle,
It is composed of lower molds 11, 12, and 13, and is configured so that the molded product always remains in a specific middle mold 12 during mold release.

That is, the upper, middle, and lower molds 11, 12, 1
3 has a three-tier structure stacked vertically in the figure, and a core 14 protruding from the center is integrally assembled into the lower mold 13. On the other hand, the middle mold 12 is ring-shaped and is assembled concentrically with the core 14 at a predetermined distance, and an annular recess 16A is formed between the lower mold 13, the core 14, and the middle mold 13. has been done. The upper mold 11 is joined to the upper end surface of the middle mold 12 and includes an annular bulge 15 that projects into the annular recess 16A, and is formed between the bulge 15 and the annular recess 16A. The space constitutes a cavity 16 filled with molding material.

The sliding surface of the upper mold 11 joined to the end surface of the middle mold 12 and the cavity forming surface facing the cavity 16 are on the same plane.

Further, a tapered convex portion 18 for forming the chamfered portion 8 between the stepped convex portions 17 is provided on the edge of the inner circumference of the middle mold 12 on the side of the upper mold 11. There is. Furthermore, a stepped convex portion 18 is provided on the edge of the upper mold side 11 of the inner periphery of the middle mold 12, projecting into the cavity 16 and biting into the outer periphery of the molded product. The stepped convex portions 18 are provided in a plurality of portions in the circumferential direction on the annular inner circumferential surface of the middle mold 12. Regarding the lengths of the stepped convex portion 18 and the tapered convex portion 18, the stepped convex portion 18 is longer than the tapered convex portion 18.

Next, a method for molding the oil seal will be explained.

First, the middle mold 12 and the lower mold 13 are assembled, and with the upper mold 11 opened, the reinforcing ring 2 is placed in the annular recess 16A that is open at the top, and the molding material is The upper mold 11 is closed with a rubber dough placed thereon, the rubber dough is heated under pressure to be fluidized, the cavity 16 is filled with the rubber dough, and the rubber dough is molded into a predetermined shape that follows the shape of the cavity 16.

At this time, the fluidized rubber fabric forms the stepped convex portion 1.
7 and the tapered convex portion 18, and a stepped groove 9 and a tapered chamfered portion 8 are formed in the molded product.

After the rubber dough is vulcanized and hardened, the mold is opened to release the molded product.

To release the mold, first, the upper mold 11 is separated from the middle mold 12, and then the lower mold 13 is separated from the middle mold 12 to take out the molded product.

When the upper mold 11 is opened, the stepped convex portion 17 on the inner periphery of the middle mold 12 bites into the stepped groove 9 formed on the outer periphery fitting portion 4 of the molded product to hold the molded product. There is. The stepped convex portion 17 reliably holds the molded product and ensures that the molded product remains in the middle mold 12.

In this embodiment, an oil seal was used as an example of the molded product, but the invention is not limited to oil seals, and is not limited to oil seals. The present invention can be widely applied to molded products in general that are configured to be left in a specific mold among a plurality of configured molds.

[0027]

[Effects of the Invention] The present invention has the above-described structure and operation, and the tapered chamfered portion is made large enough to obtain the width of the effective fitting surface, and furthermore, stepped grooves are partially provided to form the By forming the shape of the tapered chamfered part of the product using one mold shape and making the sliding surface of a specific mold a flat surface, the end of the tapered chamfered part can be made into a parting surface, unlike conventional methods. It is possible to prevent molding defects due to burrs, mold deviations, etc. of the molding material as in the case where the molding material is molded.

Further, even if there is a tapered convex portion of the mold for forming the tapered chamfered portion, the tapered convex portion is reinforced by the stepped convex portion, and there is no problem such as mold sag.

[0029] Furthermore, it is possible to save on materials, and the molded product can be reliably left in a specific mold during demolding due to the clearance of the stepped convex portion, thereby improving operability. Can be done.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a main part of an oil seal as a molded product according to an embodiment of the present invention.

2A and 2B are half sectional views of a molding die for molding the oil seal of FIG. 1. FIG.

FIG. 3 is a longitudinal cross-sectional view of a main part of an oil seal as a conventional molded product.

FIG. 4 is a sectional view of a main part of the mold for the oil seal shown in FIG. 3;

FIG. 5 is a sectional view of a main part of another conventional oil seal.

6 is a half-longitudinal cross-sectional view of the mold for the oil seal shown in FIG. 5 in a closed state; FIG.

FIG. 7 is a half-longitudinal cross-sectional view of the mold shown in FIG. 4 in a state where the molds are ground together in planes.

[Explanation of symbols]

1 Oil seal (mold molded product) 2 Reinforcement ring 3 Rubber-like elastic body 4 Outer circumferential fitting part 5 Inward flange 6 Seal lip 7 Effective mating surface 8 Tapered chamfered part 9 Stepped groove 10 Molding mold 11, 12, 13 Upper, middle, lower mold 14 Core 15 Jetty 16 Cavity 17 Stepped convex part 18 Tapered convex part

Claims (3)

[Claims] 1. A molded product comprising an outer circumferential fitting part that is closely fitted into the inner periphery of a fitting hole of a mating mounting member, and a tapered chamfered part is provided on an edge of the outer circumferential fitting part, A plurality of stepped grooves are provided along the circumferential direction on the edge of the outer peripheral fitting portion on the side where the tapered chamfered portion is provided, so as to cross the tapered chamfered portion and are partially spaced apart from each other. molded product. [Claim 2] A molded product having an outer circumferential fitting portion that is fitted into the inner periphery of a fitting hole of a mating member, the mold forming a tapered chamfered portion on the edge of the outer circumferential fitting portion. In the method for molding a molded product, step grooves that cross the tapered chamfered portion along with the tapered chamfered portion are formed on the edge of the outer circumferential fitting portion so as to be partially spaced apart along the circumferential direction. Characteristic molding method for molded products. 3. A molded product having an outer periphery fitting portion that is fitted into the inner periphery of a fitting hole of a mating member, comprising a plurality of dies that can be opened and closed with each other; In a mold in which a particular mold among the molds is provided with an annular wall for forming the outer circumference fitting part, an edge of an inner periphery of the annular wall of the particular mold is tapered along the circumferential direction. A shaped convex portion is provided, and a plurality of stepped convex portions are provided spaced apart in the circumferential direction so as to traverse the tapered convex portion, and further, the annular wall end face of the specific mold is aligned with the flat surface of another mold. A mold that is characterized by being made by joining.