JP2958144B2 - Oil seal manufacturing method - Google Patents

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 an oil seal.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a general structure of an oil seal. The oil seal 1 includes an annular metal reinforcing ring 2 having an L-shaped cross section, and a rubber seal lip 3 provided on an inner peripheral edge of the reinforcing ring 2.
The outer peripheral portion of the reinforcing ring 2 is press-fitted into a housing 4 of the counterpart device and fixed, and the seal lip 3 is pressed against a shaft 6 by a spring 5 to prevent the oil inside the housing 4 from flowing out to the outside. Intrusion of dust and the like from outside is prevented.

[0003] Such an oil seal 1 is formed, for example, by drawing a steel plate (SPCC material) by press forming to form a reinforcing ring 2, disposing the reinforcing ring 2 in a mold, and further uncured rubber. The rubber material is vulcanized and baked on the reinforcing ring 2 to form the seal lip 3 by supplying the material, closing the mold and heating for a certain period of time, and then opening the mold to remove unnecessary parts to complete the product. Let it.

[0004]

Such an oil seal is also used as a seal for a crankshaft of an automobile engine. 2. Description of the Related Art As automobiles have become more sophisticated in recent years, there has been an increasing demand for weight reduction of automobile components. As part of the weight reduction, the thickness of the reinforcing ring has been reduced.However, the reduction in the thickness of the reinforcing ring reduces the deformation resistance to external force during handling and installation of the oil seal. Therefore, it is difficult to make the reinforcing ring extremely thin. Of course, if a stronger steel sheet is used, a thin and strong reinforcing ring can be obtained, but in this case, there is a problem that press workability at the time of forming the reinforcing ring is reduced. .

[0005] The present invention is to solve such conventional problems, without deteriorating the press workability,
An object of the present invention is to provide a method for manufacturing an oil seal including a thin metal reinforcing ring having a high proof stress.

According to the present invention, in order to achieve the above object, a reinforcing ring is press-formed from a baked hard steel plate, and the formed reinforcing ring is used for vulcanization of rubber during production of an oil seal. It is characterized in that it is tempered and cured simultaneously with vulcanization using a heating temperature.

[0006] The bake hard steel sheet is a kind of bake hardening property, that is, a bake hard property, in a cold-rolled high-tensile steel sheet according to JIS (JIS G 3135). Various types are manufactured and sold as paint bake hardenable high tensile strength steel sheets. Originally, bake-hard steel sheets were developed for automobile bodies as part of measures to reduce the weight of automobiles. The bake-hard steel sheets for automobile bodies were baked at 180 ° C to 200 ° C for about 30 minutes. Tempering and hardening by heating at that time increase strength and rigidity, that is, proof stress. The bake hardness of the bake hard steel sheet changes according to the mixing ratio of the alloy component.

[0007]

The baked hard steel sheet is easy to press-form because of its excellent extensibility, and hardly causes cracks or cracks even when it is drawn. In addition, since high strength can be obtained by quenching and tempering, a reinforcing ring is formed by press molding using such a material, and at the same time, the tempering is performed by using the temperature during the vulcanization of rubber. By doing so, a light-weight, high-yield oil seal with a short manufacturing tact can be manufactured.

[0008]

An embodiment of the present invention will be described below. FIG. 1 shows an example in which the present invention is applied to a compression molding method, in which a reinforcing ring is press-molded in step 11, and the reinforcing ring is placed in a mold and unvulcanized rubber is supplied to close the mold. The method includes a step 12, a step of heating the mold for a certain period of time, vulcanizing and baking the rubber on the reinforcing ring, and a step of tempering and curing the reinforcing ring, and a step 14 of opening the mold and removing the molded product.

In step 11 of press-forming the reinforcing ring, a reinforcing ring is formed by drawing using a baked hard steel plate having a thickness of about 0.3 to 1.0 mm that has been quenched. Next, in step 12, the reinforcing ring is placed inside the compression molding die, and an unvulcanized fluorine-based rubber material or the like serving as a seal lip is placed thereon, and the die is closed. Next, in step 13,
The mold is heated for a certain period of time, and vulcanization and baking of the rubber on the reinforcing ring and tempering of the reinforcing ring are simultaneously performed to harden the reinforcing ring.

The tempering temperature of the reinforcing ring varies depending on the type of bake-hard steel plate used, the shape and thickness of the reinforcing ring, but the heating temperature for vulcanizing and baking rubber is 110 ° C. to 220 ° C.
Is selected within the range. Since the maximum strength depends on the heating temperature and the heating time at this time, it is necessary to match the selection of the heating temperature and the heating time with the heat history during the production of the oil seal.

After a lapse of a predetermined time, the mold is opened in step 14,
The molded article is taken out and subjected to necessary post-processing such as deburring. Depending on the rubber material, secondary vulcanization is performed to stabilize the rubber, but it is needless to say that this heating temperature may be used for tempering and curing the reinforcing ring. The completed oil seal has a lightweight reinforcing ring and high proof stress, and has a short manufacturing tact and a high mass-production effect, so that the cost can be reduced.

The above embodiment is an example in which an oil seal is manufactured by a compression molding method. However, the present invention can be implemented by using an injection molding method or a transfer molding method.

The present invention can be applied not only to a method of manufacturing an oil seal of an outer peripheral metal fitting type as shown in FIG. 2 but also to another method of manufacturing an oil seal of an outer peripheral rubber fitting type or a half rubber type. Can be.

As described above, according to the present invention, the reinforcing ring is press-formed from a baked hard steel plate, and the formed reinforcing ring is heated by using the heating temperature at the time of vulcanization of rubber during the production of an oil seal. Since it is tempered and cured at the same time as the sulfur, it is possible to produce an oil seal having a short production tact, low cost, high mass productivity, light weight and high proof stress.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of an oil seal showing one embodiment of the present invention.

FIG. 2 is a partial sectional view showing an example of a conventional oil seal structure.

[Explanation of symbols]

 11 Reinforcement ring press molding process 12 Reinforcement ring, rubber supply, mold closing process 13 Rubber vulcanization baking, reinforcement ring tempering process 14 Mold opening, molded product removal process

Claims (2)

(57) [Claims] 1. A metal reinforcing ring is placed in a mold, an unvulcanized rubber material is supplied into the mold, and the rubber material is heated for a predetermined time to vulcanize and bake the rubber material onto the reinforcing ring. A method for manufacturing an oil seal, wherein the reinforcing ring is press-formed from a bake hard steel plate, and the formed reinforcing ring is tempered and cured simultaneously with vulcanization using a heating temperature at the time of vulcanization of the rubber. A method for manufacturing an oil seal, comprising: 2. The method according to claim 1, wherein the rubber is vulcanized by vulcanization molding and secondary vulcanization.