JP2000018393A - Sealing device and manufacture of sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device designed to further extend its life and decrease in weight by enhancing sealability against axial eccentricity and a method for manufacturing the sealing device. SOLUTION: A first seal lip 7 made of a rubberlike elastic body is added to the end of an annular seal lip 6 and is thereby provided at the end of the annular seal lip 6 without being formed to continue from a seal part 5, whereby the amount of the rubberlike elastic body used in a sealing device 1 is decreased for weight reduction. Since the first seal lip 7 is formed independently of the seal part 5, only the first seal lip 7 may easily be added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device using a composite material of a sealing lip made of a resin material and a sealing portion made of a rubber-like elastic material.

[0002]

2. Description of the Related Art A conventional sealing device of this kind is shown in FIG.
For details, reference can be made to Japanese Patent Application No. 2-27386 filed by the applicant.

[0003] A sealing device 100 shown in FIG. 3 seals a gap between a housing 110 and a shaft 111 which move relative to each other coaxially with an air side O and a sealing side M separated from each other. A metal reinforcing ring 101 having an L-shaped cross section, a rubber-like elastic first sealing member 102 vulcanized and formed on the reinforcing ring 101, and a reinforcing ring 101 and the first sealing member 102. A second sealing member 103 made of resin that is fixed so as to be sandwiched.

[0004] A reinforcing ring 101 has a fitting portion 101a for fixing the sealing device 100 to the inner peripheral surface of the housing 110 and a flange portion 1 extending radially inward from the fitting portion 101a.
01b, and an outer peripheral sealing portion 10 formed integrally with the first seal portion 102 on the outer peripheral surface of the fitting portion 101a.
2a is provided.

Further, the sealing device 100 has a structure in which two members are combined as a sealing portion, and a high sealing performance can be satisfied for a long period of time by using only a general rubber-like elastic lip. Is one that allows it to be used in difficult and harsh conditions.

That is, the first seal member 1 is provided in the seal portion.
02, the first seal lip 102b and the second seal member 1
03 is provided with a second seal lip 103a, and each lip is provided with a different feature to enhance its function.

In this prior art, a material having high abrasion resistance and heat resistance such as PTFE (tetrafluoroethylene) is used as a resin for the second seal lip 103a, and the second seal lip 103a is operated (mainly, during operation of the sealing device 100). Even if the second seal lip 103a is urged against the sliding surface of the shaft 111 by the high pressure on the sealing side M during the rotation of the shaft 111), there is little wear and deformation, and the first seal lip 102b is turned or moved. , It is possible to maintain the sealing performance for a long period of time.

On the surface of the second seal lip 103a facing the sliding surface of the shaft 111, a thread groove 10 for generating a pump action is provided.
3b is formed, and while the shaft 111 is rotating, the sealing fluid that is flowing out from the sliding surface of the shaft 111 to the atmosphere side O is pushed back to the sealing side M to maintain high sealing performance.

On the other hand, the first seal lip 1 made of rubber-like elastic material
02b requires its own sealing performance even during rotation of the shaft 111, but rather, in this prior art, it is also an important function to seal the sealed fluid when the shaft 111 is stopped.

[0010] Therefore, in such a conventional technique, 2
It draws out the characteristics of two different materials and makes it a structure that can be used well, achieving high-performance sealing.

FIG. 4 is a view for explaining a manufacturing process of the sealing device 100 provided with the composite seal portion described in FIG.

Referring to FIG. 4A, a molding die 200 is schematically composed of a lower die 201 and an upper die 210. The lower die 201 is divided into a first die 202 forming a bottom surface, a second die 203 forming an outer diameter side wall surface, and a core 204 forming a wall surface on the inner diameter side. An external thread portion 204a is engraved on the outer peripheral surface of the core 204.

On the other hand, on the lower surface of the upper die 210, a lower die 201 is provided.
An annular protrusion 211 to be inserted therein is formed. Then, when the mold is closed, an annular cavity 220 is formed between the protrusion 211 and the lower mold 201.

Next, vulcanization molding of the sealing device 100 is performed as follows.

First, a rubber material 102 ′ is disposed in a lower mold 201 in a predetermined order as a material for a reinforcing ring 101, a second seal member 103 and a first seal member 102.

The second seal member 103 is made of PTF
A resin such as E is previously formed into an L-shaped cross section by cutting or the like. It is also conceivable that the second sealing member 130 made of a flat washer-shaped or funnel-shaped washer-shaped material is used instead of the L-shaped cross section and the mold is closed to form an L-shaped cross section. In this case, the second seal member 103 is urged by the male thread portion 204a of the reinforcing ring 101 and the core 204 via the rubber material 102 ', so that the molding position is shifted and the pressure for forming the screw groove 103b is increased. It is necessary to consider such a problem that is formed in the shape of an L-shaped cross section and consumed and cannot be sufficiently pressed.

Then, as shown in FIG. 4B, the mold is closed, and heating and pressing are performed. Rubber fabric 10 in cavity 220
2 ′ is fluidized, flows along the surface of the second seal lip 103a of the second seal member 103 and the surface of the reinforcing ring 101, and spreads to the entire area inside the cavity 220.

Then, the second seal lip 103a of the second seal member 103 softened by heat is pressed against the surface of the male screw part 204a by the pressure of the fluidized rubber material 102 ', and the screw groove 103 corresponding to the male screw part 204a is formed.
b is formed.

When the vulcanization molding is completed, the mold is opened, the molded product is taken out, and the surplus portion of the first seal member 102 is appropriately cut to complete the sealing device 100.

[0020]

However, in such a conventional technique, the sealing device 100 provided with the above-described composite seal portion is provided with the first seal member 102 and the first seal member 102.
Since the seal lip 102b is continuously formed of a rubber-like elastic body, a rubber-like elastic body for continuity is required, and the weight of the sealing device 100 is increased.

Further, since the first seal lip 102b made of a rubber-like elastic material and the second seal lip 103a made of a resin are independent of each other, when the eccentricity of the shaft 111 is large, etc. It is necessary to increase the area of the interference that comes into contact with the shaft 111 of the first seal lip 102b.
The seal lip 102b may generate heat or wear due to contact, and may shorten the life of the sealing device 100.

The present invention has been made to solve the above-mentioned problems of the prior art, and aims at improving the sealing performance against shaft eccentricity, and further increasing the life and weight of the device. An object of the present invention is to provide a sealing device and a method of manufacturing the sealing device.

[0023]

According to the present invention, there is provided a sealing device having a resin-made annular seal lip, wherein a tip end of the annular seal lip is made of a rubber-like elastic material. The seal lip is added.

Accordingly, while providing high-performance sealing performance by two different resin and rubber-like elastic seal lips, the rubber-like elastic lip is added separately, so that the rubber-like elastic The weight can be reduced by reducing the amount used.

Further, the annular seal lip absorbs the eccentricity even under the condition of high eccentricity, so that the eccentricity can be stably followed without increasing the interference of the seal lip made of the rubber-like elastic member to the member to be sealed. be able to.

It is preferable that the tip of the annular seal lip is separated from the member to be sealed.

Thus, the deformation of the rubber-like elastic lip does not affect the sealing performance of the annular seal lip.

It is preferable that the seal lip made of the rubber-like elastic body extends from the tip of the annular seal lip separated from the member to be sealed to the member to be sealed.

As a result, the seal lip made of the rubber-like elastic material can sufficiently function as a lip at the tip of the annular seal lip.

[0030] Preferably, said annular seal lip is provided with a thread groove.

According to this, the flexibility of the annular seal lip is enhanced, and when the sealing device is operated, the sealing performance of the annular seal lip is improved together with the pump action by the thread groove, and a shaft or the like is assembled to the sealing device. Workability is improved.

Preferably, the annular seal lip has a flat washer shape.

According to this, the annular sealing lip can be easily manufactured.

In the method of manufacturing a sealing device according to the present invention,
A sealing portion for mounting the annular seal lip and the reinforcing ring integrally with the annular seal lip made of resin and the reinforcing ring, and a seal lip added to a tip of the annular seal lip And vulcanization molding separately from each other.

Therefore, the sealing device can be easily completed without taking time and effort.

It is preferable that the molding die includes a thread groove forming portion for forming a thread groove in the annular seal lip, and the thread groove is formed simultaneously with vulcanization molding of the seal portion.

Accordingly, the thread groove can be easily formed without any trouble.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 1 is an explanatory sectional view of a sealing device 1 to which the present invention is applied. The sealing device 1 has an annular shape disposed in a gap between a housing 10 and a shaft 11 as a member to be sealed. The outer ring side is fitted on the inner periphery of the housing 10 as a fitting portion 2, and the inner ring side is The sealing lip 3 seals the sliding surface of the moving shaft 11.

The fitting portion 2 fixes the sealing device 1 to the inner periphery of the housing and maintains the sealing property. The fitting portion 2 is provided with a fitting rigidity by a metal reinforcing ring 4, and is provided on the outer ring portion 4 a of the reinforcing ring 4. The outer peripheral sealing portion 5a of the sealing portion 5 made of a rubber-like elastic body is integrally formed.

The seal lip 3 is made of PTFE as a resin.
A flat washer-shaped annular seal lip 6 made of resin (tetrafluoroethylene), and an annular seal lip 6
A first seal lip 7 as a seal lip made of a rubber-like elastic body and a dust lip 5b integrally formed as a part of the seal portion 5 are provided at the tip of the lip. Has become a lip.

The seal portion 5 is a rubber-like elastic body into which the reinforcing ring 4 and the annular seal lip 6 are integrally assembled.

The annular seal lip 6 has a flange 4b extending radially inward from one end of the outer ring 4a, which is a bent cross section of the reinforcing ring 4, and has a circumferential end firmly attached thereto via a rubber-like elastic body. A screw groove 6b is formed on the contact surface 6a which is fixed and which comes into contact with the sliding surface of the shaft 11.

The tip of the annular seal lip 6 is the shaft 1
1 and a rubber-like elastic body at the end thereof.
The seal lip 7 is formed and baked, and is added separately from the seal portion 5.

As in the prior art, the first seal lip 7 seals the sealed fluid at the time of stoppage without relative rotation with the shaft 11.

In the sealing device 1 having such a configuration, since the first seal lip 7 is provided at the tip of the annular seal lip 6 without being formed continuously from the seal portion 5, the rubber used for the sealing device 1 is used. The weight of the elastic body can be reduced by reducing the amount of the elastic body.

Further, the first seal lip 7 is
Since it is formed separately from the first seal lip, only the first seal lip 7 can be easily added.

Even when the shaft 11 is highly eccentric, the annular seal lip 6 absorbs the eccentricity. Therefore, even if the interference of the first seal lip 7 made of a rubber-like elastic body with respect to the shaft 11 is not increased, the shaft 11 can be rotated. 11 can be stably followed. For this reason, the tightening force of the first seal lip 7 is increased to increase the tightening force, and it is possible to prevent the life from being shortened due to heat generation or wear.

The tip of the annular seal lip 6 is
And the first seal lip 7 is provided at the tip thereof, so that the first seal lip 7 can sufficiently perform the lip action, and the deformation of the first seal lip 7 It does not affect the sealing properties of

The functions of the screw groove 6b and the dust lip 5b are the same as those according to the prior art. Further, the annular seal lip 6 may be directly attached to the reinforcing ring 4 or may be sandwiched by the reinforcing ring 4, and various methods can be applied.

Next, the molding process of the sealing device 1 will be described with reference to FIG. FIG. 2 is a cross-sectional view showing a molding step of molding the sealing device of the present embodiment. As a molding step, vulcanization molding, molding, or the like is performed according to the material of the seal portion 5.

In the present embodiment, a method of injecting and molding a fluidized rubber-like elastic body is used, and the basic configuration of the molding die is composed of a lower die 21 and an upper die 22. The lower die 21 has an outer die 21a forming an outer diameter side wall surface, and a middle die 21b holding an assembly member (a reinforcing ring 4 and an annular seal lip 6) serving as the sealing device 1 and an inner die located at the center of the lower die 21. 21c
It is composed of

The inner mold 21c is provided with a passage 21d for communicating each rubber injection port in order to form the seal portion 5 and the first seal lip 7 separately. The inner die 21c is provided with a thread groove forming portion 21e which forms a thread groove 6b on the contact surface 6a of the annular seal lip 6.

When the mold is closed, an annular cavity 23 is formed between the upper mold 22 and the lower mold 21.

The molding process of the sealing device 1 is as follows.
First, the mold is opened, and an assembly member including the reinforcing ring 4 and the annular seal lip 6 is mounted on the middle mold 21b of the lower mold 21.

Then, the upper mold 22 in an opened state (not shown)
Is closed, and a rubber-like elastic body which is fluidized and spreads is filled into the cavity 23 through the injection port, and the seal portion 5 and the first seal lip 7 are formed.

At the time of molding, the screw groove 6b is formed on the contact surface 6a of the annular seal lip 6 softened by heat by the closing pressure of the mold.
To form When the molding is completed, the mold is opened, the molded product is taken out, and an excess portion or a burr of the seal portion 5 and the first seal lip 7 and burrs are appropriately cut to complete the sealing device 1.

In this molding step, the separate seal portion 5 and the first seal lip 7 can be molded at one time, and the sealing device 1 can be completed easily without any trouble.

Further, since the annular seal lip 6 is flat, it is easy to apply pressure during molding, and the molding processability of the thread groove 6b is good.

Incidentally, the present invention is not limited to this embodiment, and the sealing portion 5
The first seal lip 7 and the first seal lip 7 can be formed by injecting different materials.

The inner end 6d of the annular seal lip 6
In the finishing method, as shown by an arrow 30, a surplus portion and burrs of the seal portion 5 and the first seal lip 7 can be removed by cutting with a cutting edge or the like to finish.

Further, the sealing device 1 may be formed by bending the annular sealing lip 6 in advance in order to easily assemble the sealing device into a used device. Of course, it is possible to bend by the axis of the used device at the same time as the assembly to the used device without performing the bending process in advance, but it is difficult to adjust the tightening force of the annular seal lip 6, This is not a preferable method because the lip 6 may be scratched or damaged. Further, by changing the shape of the molding die used so that the annular seal lip 6 is molded with a certain degree of bending at the time of molding, it may be possible to eliminate the need for bending.

[0063]

According to the sealing device of the present invention described in the above embodiment, a rubber-like elastic lip is added to the tip of the annular seal lip, so that two different resin-like and rubber-like elastic lips are used. Since the seal lip made of a rubber-like elastic body is separately provided while providing high-performance sealing performance by the body-made seal lip, the amount of the rubber-like elastic body used can be reduced and the weight can be reduced.

In addition, the annular seal lip absorbs the eccentricity even under the condition of high eccentricity, so that the eccentricity can be stably followed without increasing the interference of the seal lip made of the rubber-like elastic material to the member to be sealed. be able to. For this reason, the tightening force is increased by increasing the interference, and it is possible to prevent the life from being shortened due to heat generation or wear.

By separating the tip of the annular seal lip from the member to be sealed, the deformation of the rubber-like elastic seal lip does not affect the sealing property of the annular seal lip.

The seal lip made of rubber-like elastic material extends from the tip of the annular seal lip separated from the member to be sealed to the member to be sealed, so that the seal lip made of rubber-like elastic material functions as a lip at the tip of the annular seal lip. The function can be sufficiently performed.

Since the annular seal lip is provided with the thread groove, the flexibility of the annular seal lip is enhanced, and during the operation of the sealing device, the sealing property of the annular seal lip is improved together with the pump action by the thread groove. At the same time, workability when assembling a shaft or the like to the sealing device is improved.

Since the annular seal lip has a flat washer shape, the annular seal lip can be easily manufactured, the cost is low, and the formability in forming the thread groove is high.

According to the method of manufacturing a sealing device of the present invention, an annular sealing lip made of resin and a reinforcing ring are mounted on a mold,
By easily vulcanizing the seal part that assembles the annular seal lip and the reinforcing ring together and the seal lip that is added to the tip of the annular seal lip separately, it is easy and easy The sealing device can be completed.

The molding die is provided with a thread groove forming portion for forming a thread groove on the annular seal lip, and the thread groove is formed simultaneously with the vulcanization molding of the seal portion, so that the thread groove can be easily formed without trouble. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a sealing device according to an embodiment.

FIG. 2 is a cross-sectional view for explaining a molding step of the sealing device according to the embodiment.

FIG. 3 is a cross-sectional view showing a conventional sealing device.

FIG. 4 is a cross-sectional view illustrating a molding method of a conventional sealing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing device 2 Fitting part 3 Seal lip part 4 Reinforcement ring 4a Outer ring part 4b Flange part 5 Seal part 5a Outer peripheral sealing part 5b Dust lip 6 Annular seal lip 6a Contact surface 6b Screw groove 7 First seal lip 10 Housing 11 Shaft 21 Lower die 21a Outer die 21b Middle die 21c Inner die 21d Passage 21e Screw groove forming part 22 Upper die 23 Cavity

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 31:26

Claims (7)

[Claims] 1. A sealing device provided with a resin-made annular seal lip, wherein a seal lip made of a rubber-like elastic material is added to a tip of the annular seal lip. 2. The sealing device according to claim 1, wherein a tip of the annular seal lip is separated from a member to be sealed. 3. The sealing lip made of a rubber-like elastic body extends from the tip of the annular seal lip separated from the sealing target member to the sealing target member.
The sealing device according to claim 1. 4. The sealing device according to claim 1, wherein the annular sealing lip has a thread groove. 5. The sealing device according to claim 1, wherein the annular sealing lip has a flat washer shape. 6. A sealing portion for attaching a resin-made annular seal lip and a reinforcing ring to a molding die, and assembling the annular seal lip and the reinforcing ring integrally with each other, and a tip of the annular seal lip. A method for manufacturing a sealing device, wherein the sealing lip to be added is vulcanized and formed separately. 7. The mold according to claim 6, further comprising a thread groove forming portion for forming a thread groove in the annular seal lip, wherein the thread groove is formed simultaneously with vulcanization molding of the seal portion.
A method for manufacturing a sealing device according to item 1.