JPH07243534A - Sealing device and its manufacture - Google Patents

Abstract

PURPOSE:To provide a sealing device composed of a lip part and a supporting member for it, wherein deterioration such as change in rubber, corrosion, etc., is made unlikely and the cost is suppressed by forming the tip part from a plurality of resin lip members embodied in a single piece structure. CONSTITUTION:A sealing device 1 is formed as a PTFE lip part 10 consisting of the first and second PTFE lip members 11, 12 by pinching a ring-shaped member (a) by two metal rings 4, 5 as supporting members from both sides in axial direction and bending using a jig etc. For example, the first lip member 11 is bent to the sealing fluid while the second lip member 12 is left straight. The ring-shaped member (a) is fabricated by cutting a notch using a cutter in the direction approx. perpendicular to the axis from the internal circumference of a tubing member A made of a resin such as ethylene tetrafluoride excellent in the oil resistance, by inserting the cutter in the axial direction to generate a stepped shape, and cutting out in a specified thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device applied to, for example, an oil seal, and more particularly to a sealing device having a plurality of lips and a method for manufacturing the sealing device.

[0002]

2. Description of the Related Art As a conventional sealing device of this type, there is, for example, one shown in FIGS.

First, in FIG. 8, (a) is a half cross-sectional view of a tubular member A'made of a resin such as tetrafluoroethylene resin (hereinafter referred to as PTFE), in which a knife is inserted in a direction indicated by an arrow to form an annular shape. The member a'is obtained. This is shown in (b).

Next, the annular member a'shown in FIG. 8 (b).
As shown in FIG. 10A, the rubber material b ′ and the metal ring 104 having a substantially L-shaped cross section are pressed and heated by a molding die.
The sealing device 101 is manufactured by molding as shown in FIG. The rubber lip 102 and the PTFE lip 103 having a screw portion of the sealing device 101 molded by this
Is shown in FIG.

FIG. 9 is similar to that shown in FIG.
In (a), a tubular member A'is inserted with a knife in the direction shown by the arrow to obtain an annular member a ". This is shown in (b). This annular member a" is also not shown, but as shown in FIG. Molded,
The sealing device 101 as shown in FIG. 9C is manufactured.

[0006]

However, in the above-mentioned conventional sealing device, oil is often sealed as the sealing fluid, but in this case, the surface of the rubber lip 102 comes into contact with the oil, and the effect of curing is due to this effect. It causes deterioration such as corrosion. In particular, when used for a long period of time, there is a problem that this deterioration causes oil leakage and adversely affects other members, the machine body, and the like.

Therefore, a sealing device as shown in FIG. 11 for manufacturing a lip using only PTFE can be considered.

In FIG. 11, the sealing device 51 includes a first PTFE lip 52 for sealing a hermetic fluid and a second PTFE lip 53 for preventing dust from entering, and two metal rings 54,
It is sandwiched by 55 and attached.

A lip formed of a resin having excellent oil resistance such as PTFE does not cause deterioration such as hardening and corrosion.

However, when a plurality of PTFE lips are provided in this manner, the respective PTFE lips must be molded, and when a screw portion is required, the first P
Further, the inner peripheral surface 52a of the TFE lip 52 and the inner peripheral surface 53a of the second PTFE lip 53 are to be threaded, which requires a lot of man-hours and is costly and difficult to implement.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a sealing device in which a plurality of lips are made of resin at a low cost.

[0012]

In order to achieve the above object, the present invention provides a sealing device comprising a lip portion and a support member for supporting the lip portion, wherein the lip portion is integrated. It has a plurality of resin lips formed in.

On the other hand, an elastic annular member is prepared, a notch is provided in the annular member, and a plurality of lips are formed at a portion divided by the notch.

After forming the plurality of lips, the annular member may be assembled to the main body of the sealing device.

The elastic body is preferably made of resin.

[0016]

According to the sealing device constructed as described above, since the lip portion has a plurality of resin lips integrally formed, deterioration such as hardening and corrosion like rubber does not easily occur.

On the other hand, a plurality of lips can be easily formed by preparing an annular member made of an elastic body, providing a notch in the annular member, and forming a plurality of lips at portions divided by the notches. .

By forming the plurality of lips and then assembling the annular member to the main body of the sealing device, the sealing device having the plurality of lips can be easily manufactured.

Since the elastic body is made of resin, when the fluid to be sealed is oil, deterioration such as hardening and corrosion does not occur.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

1 to 7 show a sealing device according to the present invention.

FIG. 1 shows an example of a method for obtaining the annular member a. In (a), a direction substantially perpendicular to the axis from the inner peripheral side of a tubular member A having a hollow cylindrical shape made of ethylene tetrafluoride resin (hereinafter referred to as PTFE) having excellent oil resistance ( Insert a scalpel so that it does not penetrate in the direction of the arrow in the figure) and make a notch c.

Next, as shown in (b), a knife is inserted in the axial direction (the direction of the arrow in the drawing) to form a step.

Then, as shown in (c), a knife is inserted in a direction substantially perpendicular to the axis (the direction of the arrow in the drawing) to obtain the annular member a from the tubular member A.

The method shown here is an example, and the present invention is not limited to this method. For example, it is not necessary to insert a knife after forming a staircase, or to make a notch in particular. Alternatively, the notch c may be a groove having a certain gap.

This annular member a is for molding two lips, but of course the number, thickness, length, etc. of the lips are the diameter (inner diameter, outer diameter) of the tubular member A, how to insert a knife, etc. Can be changed by. Further, in this embodiment, the knife is inserted from the inner peripheral side of the tubular member A in a direction substantially perpendicular to the axis, but when the knife is inserted from the outer peripheral side of the tubular member A, a lip is formed on the outer peripheral side. It will be.

2 (a), (b), and (c) show a sealing device 1 according to an embodiment of the present invention, in which two metal rings 4 and 5 as supporting members are provided on both sides in the axial direction. The ring-shaped member a is sandwiched between the two and is attached, and the PTFE lip portion 10 (first PTFE lip 11 and second PTFE lip 12) is molded by bending with a jig or the like. Conventional P shown in FIG.
Since a plurality of lips are not integrated in the TFE lip, it is necessary to process each of them, which requires a lot of man-hours. Can be done by using a jig, which is easy to manufacture and reduces cost.

Although this embodiment has a seal lip on the inner peripheral side, of course, if the annular member having the notch c on the outer peripheral side as described above is used, the seal lip is provided on the outer peripheral side. Also, the material is PTF
Although E is used, any material that does not deteriorate by hardening or corrosion with respect to the sealed fluid (for example, when the sealed fluid is oil, a material having excellent oil resistance) may be used. The shapes of the metal rings 4 and 5 are also formed so as to be engageable with the peripheral (outer peripheral side) members and are not limited to the shapes shown in this embodiment.
Further, in this embodiment, the annular member a is replaced by the metal rings 4, 5
Although the bending is performed after it is attached to the (sealing device 1 main body), the bending may be performed before it is attached to the metal rings 4 and 5. The metal rings 4, 5 and the PTFE lip portion 10 are attached to each other by treating the portions of the PTFE lip portion 10 that come into contact with the metal rings 4, 5 with sodium, and roughening the surface to bond the adhesive. Although it is easy, it is not limited to this, and it is possible to firmly crimp.

Referring now to the drawing, FIG.
Only the first PTFE lip 11 of the TFE lip portion 10 is bent and molded to the sealed fluid side, and the second PTFE lip 12 is straight.

In (b), the first PTFE lip 11 is bent to the sealed fluid side, and the second PTFE lip 12 is bent to the atmosphere side to prevent dust from entering.

Further, (c) shows the first PTFE lip 1
Both the first and second PTFE lips 12 are bent and molded to the side of the sealing fluid to improve the sealing performance of the sealing fluid.

Not limited to the types (a), (b), and (c) shown here, for example, a short lip may be supported on the sealed fluid side.

3 (a) and 3 (b) show the sealing device 1 of the present invention.
The variation of (PTFE lip part 10) is shown.

In (a), the PTFE lip portion 10 shown in FIG. 2 molds two lips, whereas the PTFE lip portion 10 molds three lips. In the example, the first PTFE lip 11 and the second PTFE lip 12 are bent toward the sealed fluid side to be molded, and the third PTFE lip 13 is bent toward the atmosphere side to prevent dust from entering. Of course, the bending direction of each PTFE lip can be appropriately molded, and as described above, four lips or a plurality of lips can be molded by inserting a knife.

In (b), the metal rings 4 and 5 are not used, and the resin retainer 6 is attached as a supporting member. This is an annular member a shown in FIG. 1 that is insert-molded with a resin retainer 6.

4 to 7 also show variations of the sealing device 1 of the present invention.

FIG. 4 (a) has three lips as shown in FIG. 3 (a), and the inner peripheral surface 11a of the first PTFE lip 11 is threaded. Fitting improves the sealing performance of the sealing fluid.

In (b), the inner peripheral surface 11a of the first PTFE lip 11 is threaded.

5 (a) and 5 (b) have two lips as shown in FIG. 2, and FIG. 5 (a) shows the first PT.
Both the FE lip 1 and the second PTFE lip 2 are bent toward the sealed fluid side, and (b) is the one in which the first PTFE lip 1 is bent toward the sealed fluid side and the second PTFE lip 2 is bent toward the atmosphere side. In both (a) and (b), the inner peripheral surfaces 1a and 2a of the PTFE lips 1 and 2 are threaded. This screw processing may be the same as or different from the inner peripheral surfaces 1a and 2a.

In the embodiments of FIGS. 4 and 5, the PTFE lip portion 10 is attached to the metal ring 5 with the rubber 7. For thread processing, use PTFE
A method of simultaneously performing the bending process of the lip portion 10, a screw process after the bending process, or a bending process after the screw process can be performed. This screw may be molded with a mold or carved with a tap or the like. This can also be applied to the sealing device shown in FIGS.

The first PT shown in FIGS. 4 (a) and 5 (a)
The FE lip 1 and the second PTFE lip 2 are bent in the same direction, but their curvatures are different and the distance between the lips is wide. This is the first PTFE lip 1, the second P
This is to increase the degree of freedom of each TFE lip 2 as a lip and make it easier to move.

FIG. 6 shows the first and second PTFE lips 1 and 2.
In addition to the above, a rubber seal lip (hereinafter referred to as a rubber lip) 8 is provided.

FIG. 7 has a rubber lip 8 similar to the type shown in FIG. 6, and a metal ring 3 having a groove 31 into which an O-ring 32 is fitted is attached to the outer peripheral side.

On the other hand, FIGS. 6 (a) and 6 (b) show a manufacturing method for bending the annular member a to form the PTFE lip portion 10, and FIG. 6 (b) shows a jig for bending the annular member a. 9 is shown. In this embodiment, the screwing as in the embodiment of FIGS. 4 and 5 is not performed, but even when the screwing is performed as described above, it can be formed simultaneously with the bending by the jig.

Although the present invention integrates a plurality of lips with a resin having excellent oil resistance, this manufacturing method can be applied to not only resin but also elastic members such as rubber.

[0046]

As described above, the present invention has the above-described structure and action. Since the lip portion has a plurality of resin-made lips integrally formed, it is hard to cause deterioration such as hardening and corrosion like rubber. A sealing device having a plurality of lips formed of resin can be provided at low cost.

On the other hand, a plurality of lips can be easily formed by preparing an annular member made of an elastic body, providing a notch in the annular member, and forming a plurality of lips at the portions divided by the notches.

A sealing device having a plurality of lips can be easily manufactured by assembling the annular member to the sealing device body after forming the plurality of lips.

Since the elastic body is made of resin, even when the fluid to be sealed is oil, deterioration such as hardening and corrosion as in the conventional case does not occur, and oil leakage adversely affects other members, the machine body, and the like. There is no such thing.

[Brief description of drawings]

1A, 1B, and 1C are cross-sectional views showing a method of manufacturing a resin lip applied to a sealing device according to an embodiment of the present invention.

2A, 2B and 2C are sectional views showing a sealing device according to an embodiment of the present invention.

3 (a) and 3 (b) are sectional views showing a sealing device according to an embodiment of the present invention.

4 (a) and 4 (b) are sectional views showing a sealing device according to an embodiment of the present invention.

5 (a) and 5 (b) are sectional views showing a sealing device according to an embodiment of the present invention.

6 (a) and 6 (b) are sectional views showing a sealing device according to an embodiment of the present invention before and during jig insertion, respectively.

FIG. 7 is a sectional view showing a sealing device according to an embodiment of the present invention.

8 (a), (b), and (c) are cross-sectional views showing a conventional method for manufacturing a sealing device.

9 (a), 9 (b) and 9 (c) are cross-sectional views showing a conventional method for manufacturing a sealing device.

10 (a) and 10 (b) are cross-sectional views showing a method for manufacturing a conventional sealing device.

FIG. 11 is a cross-sectional view showing a conventional sealing device.

[Explanation of symbols]

 A, A'Tubular member a, a ', a "Annular member b' Raw rubber c Notch 1, 51, 101 Sealing device 3, 4, 5, 54, 55, 104 Metal ring (support member) 6 Resin retainer (support member ) 7 rubber 8,102 rubber lip 9 jig 10 PTFE lip portion (resin lip) 11,53 first PTFE lip 12,54 second PTFE lip 13 third PTFE lip 11a, 12a, 13a, 53a, 54a inner peripheral surface 31 groove 32 O-ring 103 PTFE lip

Claims (4)

[Claims] 1. A sealing device comprising: a lip portion; and a support member for supporting the lip portion, wherein the lip portion has a plurality of resin lips integrally formed. . 2. A method of manufacturing a sealing device, comprising: preparing an annular member made of an elastic body, providing a notch in the annular member, and forming a plurality of lips at portions divided by the notch. 3. The method for manufacturing a sealing device according to claim 2, wherein the annular member is assembled to the sealing device main body after forming the plurality of lips. 4. The method for manufacturing a sealing device according to claim 2, wherein the elastic body is resin.