JP3324323B2 - Polyphenylene sulfide resin stator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stator made of polyphenylene sulfide resin . More specifically, the present invention relates to a polyphenylene sulfide resin stator in which a metal is insert-molded or post-inserted.

[0002]

2. Description of the Related Art A polyphenylene sulfide resin molded product obtained by insert molding or post-insertion of a metal using a composition in which glass fiber chopped strands are blended with polyphenylene sulfide resin is used for stators, gears, impellers, and the like used in automatic transmissions. Used for timing belt pulleys, poly V pulleys, and the like.

[0003] For example, a stator made of polyphenylene sulfide resin is obtained by insert-molding or post-inserting a metal outer race in a portion where dimensional accuracy of an inner peripheral portion is required. By the way, polyphenylene sulfide resin usually has a cylinder temperature of about 300 to 360 ° C. and about
Molded at a mold temperature of 130 to 170 ° C.In the process of cooling after molding, internal stress accumulates in the stator body due to the difference in the coefficient of thermal expansion with the metal. Occasionally, when placed in a high-temperature atmosphere, the polyphenylene sulfide resin is further shrunk and increased.

In order to reduce such internal stress, an inorganic filler is blended with the polyphenylene sulfide resin. The inorganic filler generally has a length of about 1.5 in terms of strength, heat resistance, cost and the like. A chopped strand of about 6 mm glass fiber is used.

Incidentally, a notch or an oil hole as a flow path of oil for lubricating the one-way clutch attached to the inner peripheral side of the outer race is required on the inner peripheral portion of the stator body. Is easy to concentrate. Further, when the notch or the oil hole is formed at the time of molding, a weld portion is always formed around the notch or the oil hole, and cracks are easily generated.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a metal molded from a composition containing a polyphenylene sulfide resin and chopped strands of glass fiber.
An object of the present invention is to provide a polyphenylene sulfide resin stator in which an outer race made by insert molding or post-insertion is substantially free of cracks even in a heat cycle.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by using a linear polyphenylene sulfide having a weight average molecular weight of about 30,000 to 100,000 as the polyphenylene sulfide forming the molding composition together with the chopped strands of glass fiber.

[0008] Polyphenylene sulfide resins include cross-linked, partially cross-linked, and linear types. Among these, the cross-linked type is the lowest molecular weight polymer, and the linear type is the highest molecular weight polymer. It is a polymer. Since a certain melt viscosity is required as a molding material, the cross-linking type and the partial cross-linking type perform oxygen cross-linking by heat treatment so as to reach a required melt viscosity. On the contrary,
The linear mold is a polymer having a melt viscosity that can be sufficiently molded from the beginning without particularly performing such heat treatment.

In the present invention, such a moldable grade linear polyphenylene sulfide resin having a weight average molecular weight of about 30,000 to 100,000, preferably about 50,000 to 70,000 is used. And commercial products supplied by Toprene or the like can be used as they are. If the weight average molecular weight is lower than this, the effect of preventing the generation of cracks is not achieved, whereas if the weight average molecular weight is larger than this, not only does the effect of preventing the generation of cracks decrease, Moldability deteriorates due to a decrease in fluidity.

Further, in the present invention, a linear type polyphenylene sulfide resin having such a weight average molecular weight is used. When a crosslinked or partially crosslinked type is used instead of the linear type,
It is not possible to effectively prevent the occurrence of cracks in the heat cycle of a polyphenylene sulfide resin molded product into which metal is inserted or inserted afterwards.

The polyphenylene sulfide resin is used in this type of molding material application as a composition in which glass fiber chopped strands are blended. As a chopped strand of glass fiber, about 1000 to 30,000 glass fibers with a fiber diameter of 6 to 30 μm bundled with a binder such as epoxy resin or vinyl acetate resin and cut into 1.5 to 6 mm length, Similarly, it is used in an amount of about 5 to 200 parts by weight, preferably about 40 to 100 parts by weight, per 100 parts by weight of the polyphenylene sulfide resin.

In place of the glass fiber chopped strand, a chopped strand such as carbon fiber or aramid fiber may be used, but glass fiber is preferred in view of the strength and cost of the molded product.
However, these can be used together with those of glass fiber within a range that does not cause any trouble.

In addition to the above components, coupling agents such as silane, titanate, and aluminum for improving the adhesion between polyphenylene sulfide resin and glass fiber, coloring agents, curing accelerators, release agents, etc. Are also appropriately compounded as needed.

The molding material is prepared by kneading and pelletizing the respective components with a twin-screw extruder or the like, and the prepared molding material is subjected to injection molding, transfer molding or the like. It is molded into a molded product to be inserted later.

A polyphenylene sulfide resin molding material in which a glass fiber chopped strand is blended with a polyphenylene sulfide resin is effectively used for molding of a stator used for an automatic transmission and the like, and its crack resistance can be improved. .

[0016]

According to the present invention, a polyphenylene sulfide resin slide into which a metal outer race is insert-molded or post-inserted .
When molding the theta from a composition containing a polyphenylene sulfide resin and a chopped strand of glass fiber, by using a linear type polyphenylene sulfide resin, a molded article that is almost free of cracks even in a heat cycle is used. Obtainable.

[0017]

Next, the present invention will be described with reference to examples.

Examples Linear type polyphenylene sulfide resin Weight average molecular weight 38,900 〃 84,500 Crosslinked polyphenylene sulfide resin 〃 21,700 Partially crosslinked polyphenylene sulfide resin 〃 24,900 Each of 60 parts by weight of glass fiber having a fiber diameter of 13 μm and an average fiber length of 3 mm Was mixed with a blender and then pelletized with a twin-screw extruder.

Using the obtained pellets, a metal outer race was insert-molded by an injection molding method to form a polyphenylene sulfide resin stator. A heat cycle test was performed on each of the 10 molded articles with one cycle of 165 ° C., 1 hour and -40 ° C., 1 hour, and the number of cracks generated up to 50 cycles was measured. For those using linear type polyphenylene sulfide resin,
In each case, no cracks were observed at all up to 50 cycles. On the other hand, in the case of using the cross-linked polyphenylene sulfide resin, cracks were observed in all 10 in the first cycle, and in the case of using the partially cross-linked polyphenylene sulfide resin, all of the 10 Cracks were observed.

Claims (1)

(57) [Claims] 1. A polyphenylene sulfide resin having a weight-average molecular weight of about 30,000 to 100,000, which is formed from a composition containing a linear polyphenylene sulfide resin and a glass fiber chopped strand, into which a metal outer race is insert-molded or inserted . Stay
Ta .