JPH0193668A - Processing method for oil seal - Google Patents

Abstract

PURPOSE:To make it possible to do manufacturing at a low cost and easily when a shaft sealing lip type oil seal for a hydraulic pump or the like is processed, by conducting in division the cutting process of a cylindrical member and the processing process of the concave and convex surfaces of a groove or rib or the like. CONSTITUTION:Firstly at the process of cutting, a number of thin annular circular plate bodies 3 are cut off by cutting diametrically a cylindrical member 2 formed in synthetic resin. At the next process, a petal shaped groove concave surface 3b is processed along the perimeter edge portion of the shaft hole 3a of the circular plate body 3. After this processing, at the next formation process, the concave surface 3b of the circular plate body 3 which is made to be the upper surface, is put on the concave portion 5a of a concave mold 5, and the convex portion 6a of a convex mold 6 is put into the concave portion 5a, and the outer perimeter edge portion of the circular plate body 3 is push-pressingly fixed. Under this condition, the circular plate body 3 is heatingly treated to a predetermined tempera ture, while the perimeter edge portion of the shaft hole 3a of the circular plate body 3 is pressurized by inserting a punch 7 through the insertion hole 6b of the convex mold 6, and the perimeter edge portion of the shaft hole 3a is transformed into a rounded surface along the rounded portion 7a of the tip of the punch 7 and the portion 5c of an insertion hole 5b, and a lip portion 3c is formed and an oil seal 1 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of the Invention The present invention relates to a method of machining lip-type oil seals, such as those used for shaft seals of car coolers, compressors, hydraulic pumps, and the like.

(B) Background of the Invention Conventionally, oil seals used in the above-mentioned shaft seal include, for example, a lip-type oil seal as disclosed in Japanese Utility Model Application No. 13267/1983.

This oil seal has an annular metal frame fitted onto the inner circumferential surface of the shaft hole of the housing, a synthetic resin disk-shaped sheet fixed to the annular metal frame, and a spiral notch formed on the inner circumferential surface of the lip of the disk-shaped sheet. Alternatively, by carving a groove and making it tightly adhere to the circumferential surface of the rotating shaft, the fluid is returned along the notch or groove to prevent leakage, and to prevent seizure due to high-speed rotation and ensure smooth rotation. Attached to the rotation axis.

However, when manufacturing the above-mentioned disk-shaped sheet, a spiral notch or groove is carved in the periphery of the shaft hole of a cylindrical member made of synthetic resin, and then this cylindrical member is cut to a predetermined thickness. Since multiple disc-shaped sheets are manufactured, if you try to obtain a large number of disc-shaped sheets, you will have to cut out the notches or fillers before cutting them out, which takes time and effort to produce one disc-shaped sheet. However, the problem is that it is not suitable for mass production.

In addition, when the peripheral edge of the shaft hole of the disc-shaped sheet is pressurized or heated to curve into a lip shape, and then a spiral notch or groove is carved on the inner peripheral surface of the lip, a special shape can be formed along the curved surface. Another problem is that it is technically difficult to carve cutouts or grooves.

(C) Purpose of the Invention This invention provides excellent sealing and lubrication functions by using a unique processing method that separates the process of cutting a cylindrical member and the process of machining uneven surfaces such as grooves or lips. The purpose of the present invention is to provide a method for processing an oil seal, which can easily produce an oil seal that exhibits excellent effects at low cost.

(D) Structure of the Invention This invention comprises an annular metal frame fitted onto the inner circumferential surface of the shaft hole of a housing, a synthetic resin oil seal superposed and fixed to the annular metal frame, and a synthetic rubber seal ring. The oil seal is closely attached to the circumferential surface of a rotating shaft to prevent fluid from leaking in the axial direction, and the oil seal is first cut in a cutting process by cutting a cylindrical member made of synthetic resin in the radial direction. The thin disks are cut out one after another, and in the next processing step,
After processing an uneven surface such as a groove or lip along the circumferential edge of the shaft hole of the disc body, in the next molding process, the circumferential edge of the shaft hole including the uneven surface of the disc body is deformed, Rotating shaft circumferential surface and 85
The present invention is characterized in that it is a method of processing an oil seal to form a lip portion that is attached to the oil seal.

(e) Effects of the invention This invention includes a cutting process for cutting a cylindrical member made of synthetic resin, a processing process for forming an uneven surface such as a groove or a lip on the peripheral edge of a shaft hole of a disc body, and All steps up to the forming step of deforming the peripheral edge of the shaft hole including the uneven surface to form the lip portion are performed continuously.

(F) Effects of the Invention According to this invention, the process of cutting the cylindrical member and the process of machining uneven surfaces such as grooves or lips are performed separately in assembly work, so that various types of hydrodynamic effects can be produced on the disc body. It is possible to efficiently and easily process uneven surfaces such as grooves or rips, and it is possible to easily manufacture an oil seal that exhibits excellent sealing and lubrication functions at low cost.

Moreover, due to the moderate surface contact between the uneven surface machined on the lip of the oil seal and the peripheral surface of the rotating shaft, it is possible to obtain excellent low torque characteristics for rotation of the rotating shaft, and at the same time, it is possible to obtain excellent low torque characteristics for rotation of the rotating shaft. Seizing caused by high pressure and high-speed rotation of the rotating shaft is avoided, and wear of the rotating shaft by the oil seal is reduced, making it possible to exhibit highly stable sealing performance.

(g) Examples of the invention An embodiment of the present invention will be described in detail below based on the drawings.

The drawings show a method of processing a lip type oil seal, and in FIGS. 1 to 3, this oil seal 1 is made by first manufacturing a cylindrical member 2 made of synthetic resin such as tetrafluoroethylene resin. In the cutting process, the cylindrical member 2 is sequentially cut in the radial direction of the end surface to a predetermined thickness using a cutting means such as a cutter, thereby cutting out a large number of thin annular disk bodies 3.

After supplying the disk body 3 to the next processing step and mounting and fixing the above-mentioned disk body 3 on a flat processing table etc. (not shown), as shown in FIG. The center of the convex processed surface 4a formed in the shape of a petal of the punch 4 is aligned with the center of the shaft hole 3a of the disc body 3, and the ball is struck along the periphery of the shaft hole 3a of the disc body 3. Process the groove-like concave surface 3b.

After this processing, the processed disk body 3 is supplied to the next molding process, and as shown in FIG. Concave portion 5a of concave mold 5
The convex portion 6a of the convex mold 6 is fitted to the outer circumferential edge of the disc body 3 to press and fix it.

In this fixed state, the insertion hole 6b opened in the center of the convex mold 6 is heated while the disc body 3 is heated to a predetermined humidity using a heater or the like.
Insert the punch 7 and pressurize the peripheral edge of the shaft hole 3a of the disc body 3, and press the rounded part 7a at the tip of the punch 7 and the concave mold 5.
The circumference of the shaft hole 3a including the concave surface 3b machined into the disc body 3 is deformed into a radius along the rounded portion 5c of the insertion hole 5b opened at the center of the hole 5b, thereby forming a lip portion that comes into close contact with the circumferential surface of the rotating shaft 8. Mold 3C.

After that, each mold 5, 6 is removed, the molded disk body 3 is removed, and cooling treatment is performed by blowing cooling air etc.
The processing of the oil seal 1 into a trumpet shape as shown in FIG. 4 is completed.

As shown in FIGS. 5 and 6, this oil seal 1 has a synthetic rubber seal ring 9 superimposed on the outer surface of the lip portion 3c side of the oil seal 1, and an oil seal 1 on the sealing side. With the lip portion 3C facing, two oil seals 1 and seal rings 9 are superimposed inside the annular metal frame 10, and the outer peripheral edges of the oil seals 1 and seal rings 9 are A plate-shaped fixing ring 12 and an L-shaped fixing ring 13 are respectively fitted into the gaps formed by the bent parts 10a, 10a, which are formed by bending both side edges of the annular metal frame 10 inward. By fixing them, a seal member 14 consisting of the annular metal frame 10, the oil seal 1, and the seal ring 9 is configured.

The operation of the illustrated embodiment will be described below assuming that it is constructed as described above.

First, the sealing member 14 is fitted to the inner peripheral surface of the shaft hole 11a of the housing 11, and, for example, an O-ring is fitted to the inner peripheral surface of the shaft hole 11a to tightly seal the annular metal frame 10.

Next, a rotating shaft 8 (shown by an imaginary line in the figure) is placed at the center of the hole of the oil seal 1 and seal ring 9 that constitute the seal member 14.
By inserting the oil seal 1 through the oil seal 1, the lip portion 9a of the seal ring 9 immediately adapts to the circumferential surface of the rotating shaft 8 and forms a tight seal.
The initial leakage of fluid is prevented until the lip portion 3c of the rotary shaft 8 comes into close contact with the periphery of the rotating shaft 8.

At the same time, the back side of the seal ring 9 is supported by the oil seal 1 to prevent the lip 19a of the seal ring 9 from coming into close contact with the circumferential surface of the rotating shaft 8 more than necessary due to the high pressure applied to the sealing side, increasing the contact area. The contact surface pressure per unit area with respect to the circumferential surface of the rotating shaft 8 is kept constant, and the sealing function of the seal ring 9 is prevented from being impaired.

After that, by rotating the rotating shaft 8, the oil seal 1
The lip portion 3C gradually adapts to the circumferential surface of the rotating shaft 8 and forms a tight seal, and even if the sealing function of the seal ring 9 is impaired due to high pressure applied to the sealing side or a seizure phenomenon caused by high-speed rotation of the rotating shaft 8, The lip portion 3C of the oil seal 1 is connected to the rotating shaft 8
Since it is in close contact with the peripheral surface, leakage of fluid to the open side can be reliably prevented.

Further, when the fluid is subjected to the rotational action of the rotating shaft 8, a groove-shaped concave surface 3 is formed on the inner circumferential surface of the lip portion 3C of the oil seal 1.
b, and the hydrodynamic effect of this groove-shaped concave surface 3b can actively prevent fluid from leaking.

When manufacturing the synthetic resin oil seal 1 used for shaft seals in this way, the process of cutting the cylindrical member 2 and the process of machining the groove-shaped concave surface 3b are performed in assembly work, so it is possible to The oil seal 1 is capable of efficiently forming uneven surfaces such as various grooves or ribs that produce a hydrodynamic effect on the plate body 3, and exhibits an excellent effect on the sealing function and the lubrication function of the rotating shaft 8. It can be manufactured easily at low cost.

Moreover, by using the above-mentioned oil seal 1 as a shaft seal of a screw pump, etc., the lip portion 3C of the oil seal 1 can be
Due to the suitable surface contact between the concave surface 3b machined to the surface of the rotary shaft 8 and the circumferential surface of the rotary shaft 8, excellent low torque characteristics can be obtained for the rotation of the rotary shaft 8, and at the same time, the high pressure applied from the sealed side and the rotation shaft 8 can be It is possible to avoid seizure due to high-speed rotation of the rotary shaft 8, reduce the contact area of the oil seal 1 with the circumferential surface of the rotary shaft 8, reduce wear on the rotary shaft 8, and exhibit stable sealing performance over a long period of time.

Note that the present invention is not limited to the configuration of the above-described embodiment.

For example, as shown in FIG. 2, the seventh
A petal-shaped lip-shaped convex surface 16 as shown in the halo in the figure may be machined around the periphery of the shaft hole 3a of the disc body 3. A star shape 17, an annular shape 18, a star shape 17, an annular shape 18,
It is also possible to process various shapes such as a diamond shape 19, a spiral shape 20, etc., or a rough surface such as a lip.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, FIG. 1 is a perspective view explaining the cutting process, FIGS. 2A and 0 are perspective views explaining the processing process, and FIG. A side view, FIG. 4 is a perspective view of the oil seal, FIG. 5 is an overall perspective view of the seal member, FIG. 6 is a partially enlarged vertical sectional view of the seal member, and FIG.
The figure is a perspective view of a disc body showing another example of processing. 1...Oil seal 2...Cylindrical member 3...Disc body 3a...Shaft hole 3b...Concave surface 3C
... Lip portion 8 ... Rotating shaft 9 ... Seal ring 10 ... Annular metal frame 11 ... Housing 1
1a...Shaft hole 16...Convex surface 17...Star shape
18... Annular shape 19... Diamond shape 20.
...Spiral shape Fig. 1 3b...Concave surface Fig. 2 (B) (A) Fig. 3 Fig. 4 Fig. 5

Claims (1)

[Scope of Claims] 1. An annular metal frame is fitted onto the inner peripheral surface of the shaft hole of the housing, and a synthetic resin oil seal and a synthetic rubber seal ring are fixed to the annular metal frame by overlapping. This is an oil seal that tightly adheres to the circumferential surface of a rotating shaft and prevents fluid from leaking in the axial direction.The oil seal is first cut in the radial direction from a cylindrical member made of synthetic resin in a cutting process. Then, in the next processing step, an uneven surface such as a groove or a rib is processed along the peripheral edge of the shaft hole of the disk object, and then in the next forming step, A method of processing an oil seal, in which a lip portion that closely contacts the circumferential surface of a rotating shaft is formed by deforming the circumferential edge of the shaft hole including the uneven surface of the disc body.