JP3261309B2 - Sealing device and method of manufacturing sealing device - Google Patents

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. provide.

[0002]

2. Description of the Related Art FIG. 11 shows a conventional sealing device of this kind.
The sealing device 100 shown in FIG. 11 seals a gap between a housing 110 and a shaft 111 that move relative to each other coaxially with an air side O and a sealing side M separated from each other. A metallic reinforcing ring 101 having an L-shaped cross section to be held, a rubber-like elastic first seal member 102 vulcanized and formed on the reinforcing ring 101, and fixed so as to be sandwiched between the reinforcing ring 101 and the first seal member 102. And a second sealing member 103 made of a resin material.

[0003] 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 it is possible to satisfy a high sealing performance for a long period of time by using only a general rubber-like elastic lip. This makes it possible to use it under difficult and severe 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 characteristic to enhance the function.

In this prior art, a material having high wear resistance and heat resistance such as PTFE (tetrafluoroethylene) is used as a resin material for the second seal lip 103a, and the sealing device 100 is operated ( Mainly shaft 111
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 first seal lip, wear and deformation are reduced, and the first seal lip 102b is prevented from turning or moving. It is possible to maintain the sealing performance over a long period of time with the holding function of the above.

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 during the rotation of the shaft 111, the sealed fluid that is going to flow out from the sliding surface of the shaft 111 to the atmosphere side O is pushed back to the sealed side M to maintain high sealing performance.

On the other hand, the first first seal lip 102b made of a rubber-like elastic body needs to have its own sealing property even during rotation of the shaft 111. Sealing the sealed fluid is also an important function.

[0009] Therefore, in such prior art, 2
It draws the properties of two different materials into a structure that can be used successfully and achieves high-performance sealing.

FIG. 12 is a view for explaining a manufacturing process of the sealing device 100 provided with the composite seal portion described in FIG. For details, refer to Japanese Patent Application No. 2-2738 by the applicant.
No. 6 can be referred to.

Referring to FIG. 12A, 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 that forms a bottom surface, a second die 203 that forms an outer diameter side wall surface, and a core 204 that forms a wall surface on the inner diameter side. And
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. 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 material 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, for example, a flat washer-shaped or funnel-shaped washer-shaped material is used instead of being formed in an L-shaped cross section and the mold is closed to form an L-shaped cross section. In this case, since the second seal member 103 is urged by the reinforcing ring 101 and the male screw portion 204a of the core 204 via the rubber material 102 ', 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 an L-shaped cross section and consumed and cannot be sufficiently pressed.

Then, the mold is closed as shown in FIG.
Heat and pressurize. Rubber fabric 1 in cavity 220
02 ′ 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 portion 204a by the pressure of the fluidized rubber material 102 ', and the screw groove 103 corresponding to the male screw portion 204a is formed.
b is formed.

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

[0019]

However, in such prior art, the sealing device 100 provided with the above-described composite seal portion has special consideration regarding the connection between components made of different materials. A problem that requires

That is, the second seal member 103, which is generally made of a resin material such as PTFE, has a low bonding property with other materials. For example, the second sealing member 103 is seemingly closely bonded to a rubber-like elastic body by vulcanization molding. Although it can be seen, when an external force is applied, the joint surface is relatively easily separated, or when the diameter is increased to insert a shaft into the seal lip 103a of the second seal member 103 after vulcanization molding, the second seal is formed. There is a possibility that a large stress is applied to the member 103 and the peeling proceeds from between the member 103 and the reinforcing ring 101.

Therefore, the second seal member 103 is subjected to a surface treatment, an adhesive is applied and baked, and the bonding strength between the first seal member 102 and the reinforcing ring 101 at the time of vulcanization molding is increased to maintain the sealing performance. That is being done.

Further, for joining the metal material to the reinforcing ring 101, a mechanical fitting means (for example, unevenness on the surface or a communication hole) is provided on the flange portion 101b of the reinforcing ring 101 to improve the joining strength. However, this alone limits the sealing performance.

In particular, in the above-mentioned bonding step, a chemical treatment in which the second seal portion is immersed in a liquid compound such as metallic sodium is generally employed as a base treatment of PTFE. It requires extremely high-precision process control and the like, and tends to have low work efficiency and cost. Furthermore, in recent years, it is necessary to consider environmental conservation issues such as disposal of a processing solution.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to enable a firm fixing without impairing the sealing performance of a sealing portion using a resin material. It is another object of the present invention to provide a sealing device and a method for manufacturing the sealing device, which can eliminate the chemical treatment and the bonding process which are conventionally required.

[0025]

In order to achieve the above object, a sealing device according to the present invention comprises an annular seal lip made of a resin material and a reinforcement having a bent cross section for sandwiching a peripheral end of the annular seal lip. A ring and a sealing portion made of a rubber-like elastic material and integrally vulcanized with the reinforcing ring and the annular seal lip, and joined to the annular seal lip .

Therefore, regardless of the material, the annular seal lip is sandwiched by the reinforcing ring, and a strong connection state is maintained while maintaining the sealing performance. And the sealing performance is improved by the sealing portion made of the rubber-like elastic material.

[0027] Preferably, said annular sealing lip is provided with a thread groove.

According to this, the flexibility of the annular seal lip is enhanced, and the sealability of the annular seal lip is improved during the operation of the sealing device, and the workability when assembling a shaft or the like to the sealing device 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, a flat washer-shaped annular seal lip made of a resin material and a reinforcing ring having a bent cross section for sandwiching a peripheral end portion of the annular seal lip are previously integrated as an assembly member. Then, this assembly member is mounted on a mold, and a seal portion made of a rubber-like elastic material is vulcanized and formed, and the seal portion is joined to the annular seal lip.
You .

It is also preferable that the mold has 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.

[0033]

DETAILED 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 (not shown) and a shaft. The outer ring side is fitted on the inner periphery of the housing as a fitting portion 2, and the inner ring side moves and slides on the shaft. The seal lip 3 seals the surface.

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

The seal lip 3 is made of PTF as a resin material.
A composite lip made of a different material including a flat washer-shaped annular seal lip 6 made of E resin (tetrafluoroethylene) and a dust lip 5b integrally formed as a part of the seal portion 5. It has become.

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 an outer ring 4a opposed to the flange 4b. Of the shaft is firmly clamped by being caulked at its peripheral end by a press contact end 4c bent and extended from the other end of the shaft, and a thread groove 6b is formed on a contact surface 6a contacting a sliding surface of a shaft (not shown). Is formed.

In the sealing device 1 having such a configuration, since the annular seal lip 6 is firmly held by the reinforcing ring 4 without depending on the bonding process, there is a problem such as peeling of the annular seal lip 6 from the reinforcing ring 4. Is resolved.

Further, even when the joint surface between the annular seal lip 6 and the seal portion 5 is peeled off, the sealing performance is not deteriorated and the annular seal lip 6 is not displaced or deformed. Without becoming a major problem,
It is possible to maintain the performance of the seal portion.

The functions of the screw groove 6b and the dust lip 5b are the same as those according to the prior art.

In the sealing device 1A shown in FIG. 2, the reinforcing ring 14 has the simplest bent cross section, and has a substantially U-shape. Other configurations and operations are the same as those of the sealing device 1 described above, and the same reference numerals are given and the description thereof is omitted.

FIG. 3 shows a reinforcing ring 4 and a flat washer-shaped annular seal lip 6 previously formed as an assembly member 7 by press molding. The assembly member 7 can be formed by a pressing process as shown in FIGS. 4A to 4D. The annular seal lip 6 has a flat washer shape. It can be made by slicing the above material, and can be easily manufactured, and is advantageous in cost as compared with the L-shaped cross section.

As shown in FIG. 5, the reinforcing ring 4 has a groove 4d (FIG. 5 (a),
(B)) and the provision of the ridges 4e allow the annular seal lip 6
And the sealing performance can be improved. The surface of the reinforcing ring 4 is subjected to a roughening treatment or application of an adhesive in preparation for forming a seal portion 5 made of a rubber-like elastic material, which will be described later. Good.

Next, the molding process of the sealing device 1 will be described with reference to FIG. As a molding step, vulcanization molding, molding, or the like is performed according to the material of the seal portion 5.

The basic configuration of the molding die is the same as that of the conventional one, and comprises a lower die 21 and an upper die 22. The lower mold 21 includes an outer mold 21 a forming an outer diameter side wall surface, and an assembling member 7.
And an inner mold 21c located at the center of the lower mold 21. The inner die 21c is provided with a thread groove forming portion 21d for forming a thread groove 6b on the contact surface 6a of the annular seal lip 6.

On the other hand, on the lower surface of the upper die 22, an annular protrusion 22a inserted into the lower die 21 is formed. When the mold is closed, an annular cavity 23 is formed between the projection 22a and the lower mold 21.

The molding process of the sealing device 1 is as follows.
First, the mold is opened, and the assembly member 7 described above is mounted on the middle mold 21b of the lower mold 21. The reinforcing ring 4 makes the lower surface of the radial part 4b abut on the convex part 21e of the middle die 21b, and the flange part 4
By fitting the inner diameter end of b into the outer diameter end 21f of the inner mold 21c, positioning can be performed with high accuracy.

Then, a rubber material 5 ′ as a material of the seal portion 5, which is fluidized and expanded in the molding process and is filled in the cavity 23, is placed at a predetermined position.

The opened upper mold 22 '(two-dot chain line) is closed in the direction of arrow A1, and heating and pressurization are performed. At the time of molding, the contact surface 6 of the annular seal lip 6 softened by heat
A thread groove 6b is formed in a by the pressure of the rubber material 5 '.
When the molding is completed, the mold is opened, the molded product is taken out, and an excess portion of the seal portion 5 and burrs are appropriately cut to complete the sealing device 1.

In this molding step, there is no need to worry about the relative positional relationship between the mold and the annular seal lip 6,
As long as the position of the reinforcing ring 4 is determined, the position of the annular seal lip 6 is naturally determined. 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.

In FIG. 6, the screw groove 6b is formed only on the side of the contact surface 6a with the shaft. However, it can be formed on both surfaces for the purpose of increasing the flexibility of the annular seal lip 6. FIG. 7 illustrates the configuration. Reference numeral 6c denotes a thread groove formed on the surface of the annular seal lip 6 opposite to the contact surface 6a. The screw groove 6c is formed by the screw groove forming portion 22b provided on the annular protrusion 22a of the upper die 22, but may not be a screw groove but may be a plurality of concentric grooves because the pump operation is not intended.

When thread grooves are provided on both sides, the flexibility of the annular seal lip 6 is increased, and the followability to the eccentricity of the shaft is improved. In addition, when the tightening force is reduced, heat generation and wear are reduced. The service life can be extended.

FIGS. 8 (a) and 8 (b) show an example of the cross-sectional shape of the thread grooves 6b and 6c. Here, a mountain shape and a waveform are shown.

FIG. 9 is a view for explaining a method of finishing the inner end 6d of the annular seal lip 6 of the sealing device 1 taken out of the mold. As shown in FIG. 9A, the inner end 6 d can remove the excess portion and the burr of the seal portion 5 by cutting with the cutting edge 25. As shown in FIG. 9B, the rubber-like elastic member 6e may not be formed on the inner-diameter end 6d so that the rubber-like elastic member does not appear on the contact surface 6a side. For example, about 0.5 mm to 2.0 mm at the tip of the annular seal lip 6 is
e and the sliding surface of the shaft may be in contact with each other.

Further, as shown in the sealing device 100 of FIG. 11 in the description of the prior art, the present invention is applied to a sealing device having a structure in which a first sealing lip 102b is provided at the tip of a second sealing member 103 made of a resin material. Is applied, the rubber-like elastic member 6e may have a lip shape. In this case, by increasing the thickness of the radial portion 5c of the seal portion 5 which is formed thinner on the upper side of the annular seal lip 6 in the drawing, a tightening force can be applied to the lip during use.

FIG. 10 is a view showing a state in which the annular sealing lip 6 has been bent in advance in order to easily assemble the sealing device 1 into a used device. Reference numeral 25 denotes a lip bending jig having substantially the same diameter as a shaft of a used device inserted into the sealing device 1. The bending of the annular seal lip 6 is performed by heating with the insertion of the bending jig 25.

Of course, it is possible to bend by the axis of the used apparatus at the same time as the assembly to the used apparatus without performing the bending process in advance, but it is difficult to adjust the tightening force of the annular seal lip 6, and This is not a preferred method because the annular seal lip 6 may be damaged or damaged.

Further, by changing the shape of the mold shown in FIG.
By forming the annular seal lip 6 with a certain degree of bending at the time of molding, it is conceivable that the bending process becomes unnecessary.

[0059]

According to the present invention described in the above embodiment, the annular seal lip made of resin material is mechanically and firmly fixed to the sealing device by the reinforcing ring regardless of the material. No chemical treatment or bonding process is required to fix the slab.

Even if the joint surface between the annular seal lip and the seal portion is peeled off, it is possible to maintain the sealing performance.

By providing the annular seal lip with the thread groove, the flexibility of the annular seal lip is increased, and the sealing performance of the annular seal lip is improved during the operation of the sealing device. Workability is improved.

When 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.

[Brief description of the drawings]

FIG. 1A is an explanatory cross-sectional view of a sealing device according to an embodiment of the present invention.

FIG. 2 is an explanatory sectional view of a sealing device according to a second embodiment of the present invention.

FIG. 3 is a view of a press-formed assembly member.

FIG. 4 is an explanatory view of a pressing process of an assembly member.

FIG. 5 is a diagram of a reinforcing ring.

FIG. 6 is a diagram illustrating a molding process of the sealing device.

FIG. 7 is a diagram illustrating a molding step of the sealing device.

FIG. 8 is a diagram showing an example of a cross-sectional shape of a thread groove.

FIG. 9 is a view for explaining a method of finishing the inner end of the annular seal lip.

FIG. 10 is a view showing a state in which an annular seal lip is being bent;

FIG. 11 is an explanatory sectional view of a conventional sealing device.

FIG. 12 is a diagram 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, 14 Reinforcement ring 4a Outer ring part 4b Flange part 4c Press-contact end 4d Concave groove 4e Protrusion 5 Seal part 5'Rubber cloth 5a Outer peripheral sealing part 5b Dustrip 5c Radial part Reference Signs List 6 annular seal lip 6a abutment surface 6b, 6c screw groove 6d inner diameter end 6e rubbery elastic member 7 assembly member 21 lower die 21a outer die 21b middle die 21c inner die 21d screw groove forming part 21e convex part 21f outer diameter end 22 Upper mold 22a Convex part 23 Cavity 25 Lip bending jig

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-46371 (JP, A) JP-A-3-234977 (JP, A) JP-A-60-220269 (JP, A) JP-A-8- 128534 (JP, A) JP-A-63-1866 (JP, A) JP-A-5-38392 (JP, U) JP-A 2-59367 (JP, U) JP-A 63-182361 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16J 15/32 311

Claims (5)

(57) [Claims] 1. An annular seal lip made of a resin material, a metal reinforcing ring having a bent cross section sandwiching a peripheral end of the annular seal lip, and a reinforcing ring and an annular seal lip made of a rubber-like elastic material. Vulcanized integrally ,
A sealing portion joined to the annular seal lip . 2. The sealing device according to claim 1, wherein the annular sealing lip has a thread groove. 3. The sealing device according to claim 1, wherein the annular seal lip has a flat washer shape. 4. A flat washer-shaped annular seal lip made of a resin material and a reinforcing ring having a bent cross section for sandwiching a peripheral end of the annular seal lip are integrated as an assembly member in advance, and the assembly member is formed into a molding die. And vulcanize the seal made of rubber-like elastic material to form an annular seal lip.
A method for manufacturing a sealing device, wherein a sealing portion is joined . 5. The molding die according to claim 4, 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. Manufacturing method of sealing device.