JP3035116B2 - Manufacturing method of thrust washer for universal joint - 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 a thrust washer for a universal joint.

[0002]

2. Description of the Related Art Such a universal joint thrust washer is shown in FIG.
9532.

[0003]

The conventional thrust washer 10 shown in FIG. 1 produces a plurality of staggered radial oil grooves 20, 30 on both front and back surfaces which are slightly curved toward an outer peripheral edge and an inner peripheral edge. It is formed by injection molding in which a plastic material is injected into a mold.

[0004] In this case, it is necessary to provide a contact point of a gate and a die-cutting pin (ejector) on the plate surface 40 of the annular thrust washer. Pin marks remain, and it is necessary to perform post-processing to remove such marks.

Accordingly, an object of the present invention is to provide a method of manufacturing a thrust washer for a universal joint which does not need to be subjected to post-treatment for removing gate marks, ejector pin marks, burrs, and the like when removed from a mold after curing. To get.

[0006]

In order to achieve this object, the present invention relates to a method for manufacturing a thrust washer for a universal joint, wherein the inner diameter of the washer is larger than the inner diameter of the grease keeper and the shaft of the universal joint is provided. A thinner collar portion smaller than the inner diameter of the oil hole, and a taper so as to converge slightly toward the outside in the radial direction, and further, a cavity which causes crowning at the outer edge and directly communicates with the collar portion. Forming a mold having a sprue, injecting and molding a self-lubricating plastic material into the cavity from the sprue of the mold, and forming a plurality of ejector pins after curing to abut the collar portion. Removing the body thrust washer from the mold.

[0007]

According to the method of the present invention, the position of the sprue and the contact position of the ejector pin can be reduced by one or two steps below the surface of the effective working portion inside the effective working portion of the thrust washer. Since it is a thin part, even if a gate mark, an ejector pin mark, a burr, and the like remain, there is no effect on the operation of the thrust washer, and it is not necessary to remove these marks.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a thrust washer 1 for a universal joint manufactured by the manufacturing method according to the present invention.

As shown in FIG. 3, a cavity of a die for injection molding the thrust washer 1 has an inner diameter D larger than an inner diameter C of the grease keeper 3 and a shaft of the universal joint 4 as shown in FIG. Inner diameter E of oil hole 5
The shape is such that a thinner collar 6 is formed.

Further, as shown in FIG. 4, the mold cavity is tapered so as to slightly converge radially outward of the thrust washer, and is further formed into a shape which causes crowning at the outer edge.

A gate that directly communicates with a portion corresponding to the collar portion 6 of the mold having such a cavity is provided.

Into such a mold, a self-lubricating plastic material is injected through a gate communicating with the collar portion 6.

In another preferred embodiment, a cavity for forming an ultrathin portion communicating with the collar portion is formed in the mold further inside the collar portion, and a sprue communicating with the ultrathin portion is provided. A self-lubricating plastic material can be injected into the collar portion of the washer and the washer body via the ultra-thin portion.

After the self-lubricating plastic material injected into the cavity is cured, a plurality of ejector pins are brought into contact with the collar portion 6 of the washer 1 and the molded thrust washer 1 is taken out of the mold.

In a preferred embodiment, the molded thrust washer 1 can be press-worked after being taken out of the mold to improve the thickness accuracy and finish the surface to be smooth.

A gate mark 7 and an ejector pin mark 8 remain on the collar portion 6 of the thrust washer 1 thus formed. However, since the gate mark 7 and the ejector pin mark 8 remain on the collar portion 6 which is one step lower than the surface of the effective action portion 1a on the front and back of the thrust washer 1, there is no influence even if these marks are present. There is no need to remove.

In an embodiment in which an extremely thin portion is provided further inside the cavity corresponding to the collar portion of the mold, and a gate is formed in the extremely thin portion, after the injection molding, the extremely thin portion is cut off. There is no trace of the gate on the washer. Also, in any of the embodiments, the burr or the like at the inner diameter of the washer does not affect the action of the washer, and therefore,
Post-processing such as deburring becomes unnecessary.

On the front and back surfaces of the washer 1, an effective action portion 1a is provided.
It is preferable to provide a plurality of radial oil grooves 9 so as to be alternated between the front and back over the collar portion 6.

When the radial oil grooves 9 are provided alternately on the front and back sides, no orifice is formed in the mold cavity, so that the flow of material is improved, defective products are not generated, and the thickness accuracy can be increased. If the radial oil grooves 9 are provided at the same position on the front and back, orifices are formed in the mold cavity, so that the flow of material is deteriorated, and there is a possibility that defective products may be produced.

[0021]

According to the manufacturing method of the present invention, since the position of the sprue and the contact position of the ejector pin are applied to the collar portion lower than the surface of the effective working portion of the washer, the mark of the spout, the mark of the ejector pin, the burr, etc. However, there is no effect on the operation of the thrust washer, and it is not necessary to remove these traces.

Further, since the inside diameter D of the thin collar portion inside the effective working portion of the washer is larger than the inside diameter C of the grease keeper and smaller than the inside diameter E of the oil hole of the shaft of the universal joint, when the grease is supplied, the grease is supplied. It is blocked by this collar part and is surely guided to the oil grooves on the front and back of the thrust washer. Further, the grease liquefied after the rotation is stopped is surely guided to the grease keeper.

[Brief description of the drawings]

FIG. 1 is a plan view of a conventional thrust washer.

FIG. 2 shows a thrust washer for a universal joint manufactured by the manufacturing method of the present invention, (a) is a plan view,
(B) is a sectional view taken along line BB of (a), (c) is (a)
It is sectional drawing on the CC line of FIG.

FIG. 3 is a partial sectional view of a universal joint using a thrust washer manufactured by the method of the present invention.

FIG. 4 is a longitudinal sectional view of the thrust washer of FIG. 2;

[Explanation of symbols]

 1 Thrust washer 1a Effective working part 2 Inner diameter part 3 Grease keeper 4 Universal joint 5 Oil hole 6 Collar part 7 Gate mark 8 Ejector pin mark 9 Radial oil groove

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Claims (3)

(57) [Claims] 1. A method for manufacturing a thrust washer for a universal joint, wherein a thin collar portion having an inner diameter larger than an inner diameter of a grease keeper and smaller than an inner diameter of an oil hole of a shaft of the universal joint is formed at an inner diameter portion of the washer; Forming a mold having a cavity that is tapered so as to converge slightly toward the outside in the radial direction, and further has a cavity that generates crowning at the outer edge, and a gate that directly communicates with the collar portion; A step of injecting and molding a self-lubricating plastic material into the cavity from a mold gate, and a step of contacting a plurality of ejector pins with the collar portion after curing to remove a thrust washer of the molded body from the mold. A method for manufacturing a thrust washer for a universal joint. 2. A method for manufacturing a thrust washer for a universal joint, comprising a step of finishing the thrust washer by applying a press working to a thrust washer of a molded body after the step of removing the thrust washer from the mold. 3. A method for manufacturing a thrust washer for a universal joint according to claim 1, wherein said mold has a cavity in which said washer has a plurality of staggered radial oil grooves on both front and back surfaces.