JPH08303603A - Sealing device - Google Patents

Abstract

PURPOSE: To provide a sealing device which has a bearing function and a seal function, and whose built-in operational performance is excellent, sealing performance against extreme eccentricity is high, and manufacturing cost is low. CONSTITUTION: In a sealing device 1 installed in a housing 2, a main seal 7 and a dust lip 8 are respectively arranged on the sealing side M and the anti- sealing side T of an annular member 5, and a sliding member 6 is provided to a sliding member fixing part 5c of the annular member 5. Further, a clearance 8 is formed between a recessed fitting part 2a of the housing 2 and a fixing part 5a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gap between a housing member and a shaft which reciprocate relative to each other by the pressure of a sealing fluid, and more particularly to a high pressure sealing device.

[0002]

2. Description of the Related Art As a conventional sealing device of this type, for example, there is one which is used in a hydraulic cylinder of a hydraulic construction machine and seals high-pressure hydraulic oil.

FIG. 3 shows a conventional example of this sealing device. The sealing device 103 includes a housing 101 and an arrow A10.
The gap between the shaft 102 that reciprocates in one direction is separated into the sealing side M ′ and the atmosphere side T ′, and the high-pressure hydraulic oil sealed in the sealing side M ′ is sealed.

Further, a bearing 109 for deciding a concentric position of the shaft 102 with respect to the housing 101 is provided on the atmosphere side T'in the vicinity of the sealing device 103.

The sealing device 103 is composed of a reinforcing ring 104 and a rubber-like elastic body integrally molded with the reinforcing ring 104, and the lip portion 10 is in close contact with the sliding surface 102a of the shaft 102.
7 and a fitting portion 106 that fits in the housing 101. A rubber-like elastic body of the lip portion 107 wraps around the fitting portion 106 in order to keep the sealing property with the housing 101. Reference numeral 105 is a spring for increasing the tightening force of the lip portion 107.

Further, the sealing device 103 is provided with a high pressure hydraulic oil sealed on the sealing side M'to allow the lip portion 107 to move.
Of the backup ring 108 for preventing the sealing function from being deteriorated by moving / deforming to the atmosphere side T ′ or reversing.
Is provided on the atmosphere side T ′ of the lip portion 107.

The bearing 109 is fixed to the inner diameter side of one end of the housing 101, and is made of a metallic outer ring member 11.
0 and the bush 11 fitted to the inner circumference of the outer ring member 110.
1 is provided. The bush 111 is the sliding surface 1 of the shaft 102.
02a, and is made of a material different from that of the outer ring member 110 so as not to damage the sliding surface 102a. This material has a low sliding resistance and a high wear resistance, and a polyacetal resin or a composite material in which a resin having a sliding property is fitted inside a metallic ring is used.

Further, 111 is a dust boot for preventing the intrusion of external dust existing on the atmosphere side T '.

[0009]

In such a conventional technique, when the sealing device 103 is incorporated into the housing 101, the fitting portion 106 of the sealing device 103 is a rubber-like elastic body. Direction and sealing device 1
If the shaft of 03 is tilted even a little, it becomes impossible to insert it, and if the insertion position is not accurately determined, an axial gap will occur between the shaft and the bearing 109 that will be incorporated later, so a precise insertion cure will occur. It is inserted using the tool. Further, the sealing device 103 and the bearing 109 need to be installed separately,
It took a long time to install.

Further, the sealing property of the built-in sealing device 103 with the housing 101 side is maintained by the fitting portion 106 of the rubber-like elastic body as described above. When the shaft 102 is excessively eccentric, the fitting is performed. There is also a problem that the portion 106 bends in the eccentric direction and the surface pressure on the outer peripheral surface of the fitting portion 106 becomes non-uniform, and high-pressure hydraulic oil leaks from the fitting portion 106 and the inner peripheral surface of the housing 101. It was

On the other hand, the bearing 109 has a high dimensional accuracy in the axial direction in which it is in contact with the fitting portion with the housing 101 and the sealing device 103, resulting in high component cost and high cost.

Further, although the dust boot 111 is attached to prevent the intrusion of external dust, there are problems such as a defect in the mounting portion of the dust boot and the intrusion of external dust from the drain hole in the bellows. In technology, bearing 10
There is no other way but to additionally provide a dust seal on the atmosphere side T ′ of 9 and this was also one of the factors of cost increase.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is that the assembling work is easy and can be performed in a short time. To provide a low-cost sealing device having high sealing performance.

[0014]

In order to achieve the above object, according to the present invention, a mounting portion provided on either one of the coaxially arranged housing and the facing surface of the shaft, and the mounting portion. A sealing device for sealing a gap between an opposing surface of the other member that moves relative to the fixing member, the fixing portion engaging with the mounting portion, and the other member facing the fixing member via a radial portion. An annular member having a sliding member fixing portion close to the surface, a main seal having at least a lip portion in close contact with the facing surface of the other member on the sealing side of the annular member, and an anti-sealing side of the annular member. A dust lip that is in close contact with the facing surface of the other member, and an annular sliding member that is disposed between the sliding member fixing portion of the annular member and the facing surface of the other member. It is characterized by

However, it is also preferable to equip the end of the sliding member on the sealed side with a backup portion that abuts against the non-sealed side of the lip portion of the main seal and carries the lip portion.

Further, it is also preferable that the sliding member fixing portion of the annular member is provided with a backup portion at the sealing side end portion, which comes into contact with the non-sealing side of the lip portion of the main seal and carries the lip portion. .

A predetermined gap is provided between the fixed portion of the annular member and the mounting portion of the housing or the shaft, and the main seal is in contact with at least two facing surfaces of the housing and the shaft. It has a lip part.

It is also preferable that the main seal and the dust lip are integrally formed through a hole provided in a radial portion of the annular member.

Further, it is also preferable that the annular member and the sliding member are integrally formed of the same member.

[0020]

In the present invention having the above-described structure, in order to facilitate understanding of the explanation, when the sealing device is attached to the housing member side, the fixing portion of the annular member is the housing member. The sliding member fixing portion of the annular member is fixed to the mounting portion and holds the sliding member. Then, it becomes a bearing that holds the shaft on which the annular member and the sliding member that are integrated move.

Further, the main seal, which is provided on the sealing side of the annular member and has a lip portion that is in close contact with the facing surface of the shaft, is in close contact with the moving shaft and seals the gap between the shaft and the housing.

Further, the dust lip provided on the non-sealing side of the annular member is in close contact with the moving shaft to prevent dust from entering the sealing side.

Therefore, the sealing device according to the present invention functions as a bearing, a sealing device for the sealed fluid, and a dust seal for preventing dust from entering on the non-sealing side.

Further, the backup portion of the sealing side end of the sliding member or the sealing side end of the sliding member fixing portion of the annular member is brought into contact with the non-sealing side of the lip portion of the main seal,
It acts as a backup ring that suppresses the behavior of the main seal due to the pressure of the enclosed fluid.

The gap provided between the fixed portion of the annular member and the mounting portion of the housing allows the annular member to be easily inserted into the mounting portion of the housing, and allows eccentricity within a predetermined range of the shaft. To do. However, even if the shaft is eccentric within a predetermined range, the enclosed fluid does not leak due to the lip portions that are in close contact with the facing surfaces of the housing and the shaft, and the eccentricity is excellent.

Further, through the holes provided in the radial portion of the annular member, the material flows at the time of molding the sealing device, and the main seal and the dust lip are simultaneously molded integrally.

Further, even when the annular member and the sliding member are integrally provided by the same member, the main seal and the dust lip are attached to the annular member through the holes provided in the radial direction portion of the annular member. Since they are structurally joined, it is possible to use, for the annular member, a material (a material having high slidability) having poor seizure and adhesion between the main seal and the rubber-like elastic body which is the material of the dust lip.

[0028]

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

(First Embodiment) FIG. 1 shows the first embodiment of the present invention applied to a high-pressure sealing device 1. The sealing device 1 is arranged in a gap between the housing 2 and the shaft 3 facing each other. It was done.

The sealing device 1 is provided on the inner peripheral surface side of the housing 2.
There is provided a concave ring portion 2a as a mounting portion for mounting the, a flange portion 2b, and a snap ring groove 2c for fitting the snap ring 4 therein.

Therefore, the sealing device 1 is mounted on the housing 2 by sliding through the gap between the housing 2 and the shaft 3 from the left side to the right side in FIG. 1, and the snap ring 4 is fitted therein so that the sealing device 1 is prevented from moving in the axial direction. There is. However, the mounting method of the sealing device 1 is not limited to this embodiment, and various known methods can be used. As an example, if two snap ring grooves are provided on the inner peripheral surface of the housing 2 and the sealing device is fixed between them, step processing on the inner peripheral surface of the housing 2 can be eliminated.

Next, the structure of the sealing device 1 will be described in detail. The sealing device 1 is composed of four main components, which are an annular member 5, a sliding member 6 attached to the annular member 5, a main seal 7 and a dust lip 8.

The annular member 5 is a concave ring portion 2a of the housing 2.
Is provided with a fixed portion 5a that engages with, a radial portion 5b that extends from the fixed portion 5a in the direction of the shaft 3, and a sliding member fixed portion 5c that is close to the surface of the shaft 3. The fixed portion 5a is attached to the concave ring portion 2a of the housing 2, and a minute gap 8 is formed between the fixed portion 5a and the concave ring portion 2a. Further, the radial portion 5b has a hole 5d penetrating in the axial direction.
The main seal 7 is opened through the hole 5d.
And the dust lip 8 are integrated. The sliding member 6 is fixed to the sliding member fixing portion 5c.

The sliding member 6 determines the concentric position of the reciprocating shaft 3 with respect to the housing 2. It is a material having a low sliding resistance and a high abrasion resistance, and the surface of the shaft 3 is not damaged. A composite material in which a polyacetal resin or a resin having slidability is fitted inside a metallic ring is used.

The main seal 7 is provided with lips 7a and 7b which are in close contact with the shaft 3 and the housing 2, respectively.
Reference numeral 9 is a spring that increases the tightening force for bringing the lip portion 7a into close contact with the shaft 3. Further, the main seal 7 is of a type having a backup ring that stabilizes the behavior of the pressure of the fluid enclosed in the lip portion 7a and the reciprocating movement of the shaft 3, and the backup portion 6a which is the end portion of the sliding member 6 on the sealing side.
Plays a role of a backup ring by coming into contact with the anti-sealing fluid side of the lip portion 7a.

The dust lip 8 is provided on the side opposite to the hermetically sealed side of the annular member 5 and is in close contact with the shaft 3. The dust lip 8 and the main seal 7 are integrated through the hole 5d, and in the manufacturing process of the sealing device 1, the hole 5d is made of a rubber-like elastic material as a material on the left and right of the hole 5d (in FIG. 1).
The holes are evenly distributed to allow flow in the same direction.

With this structure, in the sealing device 1, the sliding member 6 acts as a bearing of the shaft 3, at the same time, the main seal 7 acts as a sealing device for the sealed fluid, and the dust lip 8 on the anti-sealing side acts as a dust seal. To do.

The fixed portion 5a of the annular member 5 and the housing 3
The gap 8 provided between the concave ring portions 2a allows the annular member to be easily inserted into the mounting portion of the housing, and allows the shaft 3 to be eccentric within a predetermined range. However, even if the shaft 3 is eccentric within a predetermined range, the sealed fluid does not leak because the shaft 3 provided on the main seal 7 and the lip portions 7a and 7b closely contacting the facing surfaces of both members of the housing 2 are in close contact with each other. Rather, it excels in eccentricity tracking.

(Second Embodiment) FIG. 2 shows a second embodiment. In this embodiment, the lip portion 27a of the main seal 27 is used.
Back up the sliding member fixing portion 25 of the annular member 25.
This is performed by the backup unit 25e provided at the sealed end of c.

In the annular member 25 of the second embodiment, the radial portion 25b extends toward the atmosphere side T and is folded back toward the sealed side M. 25a is a fixed part and 25d is a hole.

The sliding member 26 is fixed to the folded sliding member fixing portion 25c.

According to this shape, the sliding member 26 which requires a predetermined dimension in the longitudinal direction of the shaft 3 can be firmly fixed by the annular member 25.

The other structure and operation are the same as those of the first embodiment described above, and therefore, the same components are designated by the same reference numerals and their description is omitted.

[0044]

The present invention has the above-described structure and operation, and is composed of a bearing, a sealing device for a sealed fluid, and a plurality of components, which function as a dust seal on the anti-sealing side and prevent dust from entering, are integrated. By function, a reliable sealing device is obtained.

Therefore, conventionally, it was necessary to assemble each constituent element separately, but it is possible to assemble the sealing device according to the present invention at one time, and the assembling work time can be shortened.

Further, since the outer ring member of the bearing, which is a highly accurate machined component, and the independent backup ring are eliminated, the number of components is reduced, and the sealing device can contribute to the overall price reduction.

Due to the gap provided between the fixing portion of the annular member and the mounting portion of the housing, the annular member can be easily inserted into the mounting portion of the housing without using a precise insertion jig. It will be possible.

Further, even if the shaft is eccentric within a predetermined range, the sealed fluid does not leak due to the lips which are provided in the main seal and which are in close contact with the facing surfaces of the housing and shaft members, and the eccentricity does not leak. Is excellent.

Further, through the holes provided in the radial portion of the annular member, the material flows at the time of molding the sealing device, and the main seal and the dust lip are simultaneously molded integrally.

Further, even when the annular member and the sliding member are integrally provided by the same member, the main seal and the dust lip are attached to the annular member through the holes provided in the radial direction portion of the annular member. Since they are structurally joined, it is possible to use, for the annular member, a material (a material having high slidability) having poor seizure and adhesion between the main seal and the rubber-like elastic body which is the material of the dust lip.

[Brief description of drawings]

FIG. 1 is a sealing device according to a first embodiment of the present invention.

FIG. 2 is a sealing device according to a second embodiment of the present invention.

FIG. 3 is a bearing and sealing device according to the prior art.

[Explanation of reference numerals] 1,20 Sealing device 2 Housing 3 Shaft 4 Snap ring 5,25 Annular member 5a, 25a Fixed part 5b, 25b Radial direction part 5c, 25c Sliding member fixed part 5d, 25d Hole 25e Backup part 6, 26 sliding member 6a, backup section 7,27 main seal 7a, 7b, 7c, 7d 8 dust lip 9 spring

Claims (6)

[Claims] 1. A gap between a mounting portion provided on either one of a housing and a shaft facing surface that are coaxially arranged, and a facing surface of another member that moves relative to the mounting portion is sealed. An annular member having a fixing portion that engages with the mounting portion and a sliding member fixing portion that is close to the facing surface of the other member via the radial portion from the fixing portion, and the annular member. A main seal having a lip portion that is in close contact with the facing surface of the other member on the sealing side of the member; a dust lip that is in close contact with the facing surface of the other member on the anti-sealing side of the annular member; A sealing device, comprising: a sliding member fixing portion of a member and an annular sliding member disposed between the facing surface of the other member. 2. A backup portion, which is provided at an end portion on the sealing side of the sliding member, abuts against a non-sealing side of a lip portion of the main seal and carries the lip portion. Sealing device. 3. A backup portion is provided at an end portion on the sealing side of a sliding member fixing portion of the annular member, the backup portion being in contact with a non-sealing side of a lip portion of the main seal and carrying the lip portion. The sealing device according to claim 1. 4. A predetermined gap is provided between a fixed portion of the annular member and a mounting portion of the housing or the shaft, and the main seal is in close contact with at least two facing surfaces of the housing and the shaft. The sealing device according to claim 1, wherein the sealing device is provided with one lip portion. 5. The main seal and the dust lip are integrally formed through a hole provided in a radial portion of the annular member, according to claim 1, 2, 3 or 4. The sealing device described. 6. The sealing device according to claim 5, wherein the annular member and the sliding member are integrally formed of the same member.