JP2003004143A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device decreased in slide resistance and a stick slip and having high reliability. SOLUTION: The sealing part is provided with a central part 2b in the axial direction making close contact with a shift and a taper part 2c inclining in the direction in which a distance with the shaft is increased from the central part 2b toward the high pressure side during action of pressure of an object fluid to be sealed. The taper part 2c forms a slide surface, making close contact with the shaft during action of pressure of the object fluid to be sealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device used in, for example, a shaft sealing portion of various devices.

[0002]

2. Description of the Related Art Conventionally, for example, in a shaft sealing portion of a device on which a high-pressure fluid to be sealed acts, for example, an inner peripheral surface of a shaft hole of a housing and an outer peripheral surface of a shaft inserted into the shaft hole (rotation relative to the shaft hole A sealing device is provided to prevent leakage of sealing fluid from the annular gap between the shaft and the piston relative to the cylinder).

In the sealing device, as a rotary seal,
For example, it is used for construction machines such as power shovels and cranes, and industrial machines such as rotary joints. The rotary seal of the construction machine switches the hydraulic pressure supplied to each cylinder, and is usually installed in the center of the vehicle body.

If a problem occurs with the seal, it is difficult to replace the seal because it is installed in the center of the vehicle body, and normally durability of 6000 hours or more is required. Further, long-term durability is also required for industrial machines.

Further, as a problem of the seal,
When the tightening margin is insufficient due to wear, and the protrusion is often caused by insufficient pressure resistance, and when longer life is generally required, a slipper ring made of a resin material is used for the sliding surface and an elastic material is used as the back ring. (Adhesive) type sealing device used in the above is used.

FIG. 3A shows such a sealing device 100.
FIG. 1B is a schematic cross-sectional configuration diagram of the sealing device 10 shown in FIG.
It is a schematic diagram showing the state where 0 was attached.

The sealing device 100 has a resin material (for example, nylon, Teflon (registered trademark), etc.) arranged on the inner peripheral side.
Slipper ring 101 and slipper ring 101
A back ring 102 made of a rubber-like elastic body (for example, NBR (nitrile rubber), urethane rubber, etc.) that is provided on the outer peripheral side of the slipper ring 101 and applies a tightening force to the slipper ring 101.
Are bonded together.

In FIG. 3B, the shaft hole 111 and the shaft 112 of the cylinder housing 110 are coaxially arranged, and the shaft 112 is stopped and rotated (depending on the specifications of the applied device). Operations such as stopping, rotating, rocking, and reciprocating are performed). Then, the cylinder housing 110
The inner peripheral surface 113 is provided with an annular groove 114 having a rectangular cross section, and the sealing device 100 is attached thereto.

In the sealing device 100, the inner peripheral surface 101a of the slipper ring 101 is a sliding surface with the shaft 112.

Therefore, the sealing device 100 having such a structure.
Is excellent in settling resistance, wear resistance and pressure resistance due to the characteristics of the resin material forming the slipper ring 101 by using the slipper ring 101 on the sliding surface. By combining the above, the resin ring having a low elasticity can be given a tension force to be brought into contact with the opposing sliding surface (the shaft 112 in FIG. 3) at a predetermined pressure to exhibit the sealing property.

[0011]

However, in the case of the above prior art, the following problems occur.

In recent years, there is a strong demand for improvement in pressure resistance, and in many cases, the slipper ring 101 made of a nylon material is used.

However, the nylon material has a high coefficient of friction and is inferior in sliding characteristics, and when the slipper ring 101 is made of this nylon material and applied to a shaft sealing portion of various devices, it is short. Over a period of time (several hundreds of hours at the earliest), the sliding resistance becomes large, causing malfunctions such as malfunctions and stick-slips.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a highly reliable sealing device with reduced sliding resistance and stick-slip. is there.

[0015]

In order to achieve the above object, in the present invention, the annular gap is fitted into an annular groove formed on either one of the two facing surfaces forming the annular gap. And a sliding ring having a sliding surface that is in close contact with the other surface, and a sliding ring that is provided on the opposite side of the sliding ring from the sliding surface. In a sealing device including a biasing ring that biases a surface, the facing surface of the sliding ring that faces the other surface is in close contact with the other surface when the pressure of the fluid to be sealed is not acting. An axially central portion, and an inclined portion that is inclined from the central portion in a direction in which a gap between the other surface is widened toward a high pressure side when the fluid to be sealed is subjected to a pressure, the inclined portion, Sliding that comes into close contact with the other surface when the pressure of the fluid to be sealed is applied. Characterized in that the surface.

With this configuration, when the pressure of the fluid to be sealed is applied, the area of the sliding surface that slides on the other surface can be made smaller than before, so the sliding resistance is reduced. Can be made.

Furthermore, by reducing the sliding resistance, it is possible to suppress stick slip.

It is also preferable to provide a groove in the circumferential direction on the inclined portion.

With this structure, it is possible to maintain a state in which the fluid to be sealed is always present in the inclined portion that serves as the sliding surface when the fluid to be sealed is acted on by pressure. Can be good. Therefore, since the sliding resistance can be reduced, it is possible to suppress the stick slip.

It is also preferable to provide a circumferential groove on the side surface of the biasing ring.

With this structure, the sliding ring can be easily swung. Therefore,
The inclined portion can be brought into close contact with the other member easily and reliably. Further, it is possible to improve the followability to the eccentricity of the other member.

It is also preferable to provide a radial groove that connects the inclined portion and the groove provided in the biasing ring.

With this structure, the fluid to be sealed can be supplied to the groove provided in the urging ring.

The sliding ring may be made of a resin material, the biasing ring may be made of a rubber-like elastic body, and the sliding ring and the biasing ring may be provided in contact with or connected to each other. It is suitable.

With this structure, the resin material has excellent fatigue resistance, wear resistance, and pressure resistance due to the characteristics of the resin material. By combining the resin sliding ring and the rubber-like elastic body, the elasticity can be improved. It is possible to exert a tight force on a resin ring having a low pressure and bring it into contact with the opposing sliding surface at a predetermined pressure to exhibit a good sealing property.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
The material, the shape, and the relative arrangement of them should be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions, and the scope of the invention is not limited to the following embodiments.

FIG. 1 is a schematic view showing a sealing device 1 according to an embodiment of the present invention, (a) is a schematic top view, and (b) is a schematic view.
Is a schematic cross-sectional view. FIG. 2 is a schematic view showing a state in which the sealing device 1 according to the embodiment of the present invention is mounted,
(A) shows the case where the pressure P is applied from above, and (b) shows the case where the pressure P is applied from below.

The sealing device 1 has an annular groove formed on one of the surfaces of the cylinder housing 4 and the shaft 5 inserted into the shaft hole 4a of the cylinder housing 4 as the two opposing surfaces forming an annular gap. It is fitted and seals the annular gap.

In this embodiment, the case where the sealing device 1 is fitted into the annular groove 4b formed in the cylinder housing 4 as one surface will be described.

In FIG. 1, the shaft hole 4a of the cylinder housing 4 and the shaft 5 forming the other surface are arranged coaxially, and the shaft 5 is stopped and rotated (applied). Depending on the specifications of the device, stop, rotation, swing,
Actions such as reciprocating motion are made). An annular groove 4b having a rectangular cross section is provided on the inner peripheral surface 4c of the cylinder housing 4, and the sealing device 1 is mounted in the annular groove 4b.

The sealing device 1 has an annular shape, and a slipper ring 2 as a sliding ring made of a resin material (for example, nylon, Teflon, etc.) arranged on the inner peripheral side,
Attached by a rubber-like elastic body (for example, NBR (nitrile rubber), urethane rubber, etc.) that is provided on the outer peripheral side of the slipper ring 2 and gives a tightening force to the slipper ring 2 when the sealing device 1 is provided in the annular gap 4a. The back ring 3 as a bias ring is adhered.

In the sealing device 1, the inner peripheral surface 2a of the slipper ring 2 is a facing surface facing the shaft 5,
It will be in close contact with the axis 5.

In this embodiment, the slipper ring 2 and the back ring 3 are connected to each other by adhesion, but the back ring 3 exerts a tightening force on the slipper ring 2 to move the slipper ring 2 into the shaft 5. The slipper ring 2 and the back ring 3 may be brought into contact with each other as long as they are in close contact with each other, or may be connected by another method.

The characteristic structure of the present embodiment will be described below.

As shown in the figure, the slipper ring 2 has a central portion 2b provided at the center in the axial direction on the inner peripheral surface 2a and a high pressure side (from the central portion 2b when the fluid to be sealed is acted on by pressure). A tapered portion 2c as an inclined portion that inclines in a direction in which the distance from the shaft 5 increases toward the P side in the drawing;
Is equipped with.

By forming the inner peripheral surface 2a of the slipper ring 2 into such a shape, the central portion 2b is in close contact with the shaft 5 when the pressure of the fluid to be sealed does not act, and when the fluid to be sealed is acted on by the pressure. When the back ring 3 is bent by the pressure P, the slipper ring 2 swings, and the tapered portion 2c
Comes into close contact with the shaft 5, and the tapered portion 2c serves as a sliding surface with the shaft 5.

In this embodiment, as shown in FIG. 2, both sides of the sealing device 1 may be on the high pressure side when the pressure of the fluid to be sealed acts, so that the tapered portion 2c is as shown in FIG. In addition, although it is provided on both sides of the central portion 2b, when the high pressure is applied to only one side of the sealing device 1, the tapered portions 2c do not need to be provided on both sides of the central portion 2b, and the tapered portion 2c is not necessary. It may be provided only on one side of the high voltage side.

The axial widths of the central portion 2b and the tapered portion 2c may be appropriately set according to the specifications of the apparatus, and the central portion 2b may have an R shape.

Further, the tapered portion 2c is provided with a groove 2d in the circumferential direction.

As a result, it is possible to maintain the state in which the oil as the sealing target fluid is always present in (the groove 2d of) the tapered portion 2c which becomes the sliding surface when the pressure of the sealing target fluid is applied. The lubrication state can be improved.

The back ring 3 has an inner peripheral surface adhered to the slipper ring 2, and an outer peripheral surface mounted on the bottom surface of the annular groove 4b. A circumferential groove 3a is provided on the side surface 3b.

By providing the groove 3a, the back ring 3 is more easily bent, and when the pressure of the fluid to be sealed acts, the slipper ring 2 is swung so that the tapered portion 2c is easily brought into close contact with the shaft 5. Will be able to. Further, it is possible to improve the followability to the eccentricity of the shaft 5.

Further, the taper portion 2c of the slipper ring 2
And a groove 6 that communicates with the groove 3a of the back ring 3. The groove 6 is an oil passage for supplying oil to the groove 3a.

In the sealing device 1 thus constructed, for example, a construction machine such as a power shovel or a crane,
Used in industrial machinery such as rotary joints, sealing from the annular gap between the inner peripheral surface of the shaft hole of the cylinder housing and the outer peripheral surface of the shaft inserted into the shaft hole (rotating shaft for shaft hole or piston for cylinder). This is to prevent fluid leakage.

When the pressure of the fluid to be sealed is not acting, the central portion 2b of the slipper ring 2 is in close contact with the shaft 5, and when the pressure of the fluid to be sealed is applied, the back ring 3 is bent by the pressure P to cause the slipper to slip. The ring 2 swings so that the tapered portion 2c comes into close contact with the shaft 5.

Therefore, the sliding surface with the shaft 5 is shown in FIG.
As shown by A and B in (a) and (b), respectively,
The area of the sliding surface is smaller than that of the conventional sealing device in which only the tapered portion 2c of the inner peripheral surface 2a of the slipper ring 2 is used and the entire inner peripheral surface is the sliding surface as shown by C in FIG. 3 (b). Since it can be reduced to 1/2 or less, the sliding resistance can be reduced. Furthermore, by reducing the sliding resistance, it becomes possible to suppress stick slip.

Further, by providing the groove 2d in the circumferential direction of the taper portion 2c, the inside of the taper portion 2c (the groove 2 of the slipper ring 2 which becomes a sliding surface when the fluid to be sealed acts on pressure).
Since the state in which oil is always present in d) can be maintained, the lubrication state of the sliding surface (2c) can be improved.

Therefore, since the sliding resistance can be reduced, the stick-slip can be suppressed.

Further, the sliding resistance is reduced, and
Since the oil always exists in (the groove 2d of) the tapered portion 2c, the wear resistance can be improved and the heat generated by the sliding can be suppressed.

Since the back ring 3 is more easily bent by providing the groove 3a on the side surface of the back ring 3, the slipper ring 2 can be easily swung when the pressure of the fluid to be sealed acts. Therefore, easily
Then, the tapered portion 2c can be surely brought into close contact with the shaft 5. Further, it becomes possible to improve the followability to the eccentricity of the shaft 5.

Also, the taper portion 2c of the slipper ring 2
Since the oil can be supplied to the groove 3a by providing the radial groove 6 that communicates with the groove 3a of the back ring 3, it is possible to maintain a good lubrication state in the back ring 3. The durability of the ring 3 can be improved.

Therefore, the sealing device 1 having such a configuration is
By using the slipper ring 2 on the sliding surface, the characteristics of the resin material forming the slipper ring 2 make it excellent in settling resistance, wear resistance and pressure resistance, and combining the resin ring with a rubber-like elastic body. By applying a tightness force to the resin ring having low elasticity, the shaft 5 which is the opposing sliding surface is brought into contact with the shaft 5 at a predetermined pressure to reduce the sliding resistance and suppress the stick-slip. It becomes possible to exert the nature.

[0053]

As described above, according to the present invention,
The inclined portion serves as a sliding surface that comes into close contact with the other surface when the pressure of the fluid to be sealed acts, so that the area of the sliding surface that slides on the other surface can be made smaller than before. The sliding resistance can be reduced. further,
By reducing the sliding resistance, stick slip can be suppressed.

Further, by providing the groove in the circumferential direction in the inclined portion, it is possible to maintain the state in which the fluid to be sealed is always present in the inclined portion which becomes the sliding surface when the fluid to be sealed is applied with pressure. Therefore, the lubrication state of the sliding surface can be improved. Therefore, since the sliding resistance can be reduced, it is possible to suppress the stick slip.

Further, since the sliding resistance is reduced and the fluid to be sealed is always present in the circumferential groove of the inclined portion, the wear resistance can be improved and the heat generated by sliding can be improved. Can also be suppressed.

[Brief description of drawings]

FIG. 1 is a schematic view showing a sealing device according to an embodiment of the present invention, (a) is a schematic top view, and (b) is a schematic sectional view.

FIG. 2 is a schematic view showing a state in which the sealing device according to the embodiment of the present invention is mounted.

FIG. 3 is a schematic view showing a sealing device according to the prior art,
(A) is a schematic sectional drawing, (b) is a schematic diagram which shows the state with which the sealing device was mounted.

[Explanation of symbols]

1 Sealing device 2 slipper rings 2a Inner surface 2b central part 2c taper part 2d groove 3 buckling 3a groove 3b side 4 cylinder housing 4a shaft hole 4b annular groove 4c Inner surface 5 axes 6 grooves

Claims (5)

[Claims] 1. A sealing device which is fitted into an annular groove formed in one of two facing surfaces forming an annular gap to seal the annular gap, the sliding surface being in close contact with the other face. And a biasing ring that is provided on a side opposite to the sliding surface of the sliding ring and biases the sliding ring to the other surface. The facing surface of the sliding ring, which faces the other surface, has a central portion in the axial direction in close contact with the other surface when the pressure of the sealing target fluid is not acting, and a pressure acting of the sealing target fluid from the central portion. An inclined portion that inclines in a direction in which the distance from the other surface widens toward the high pressure side, and the inclined portion slides in close contact with the other surface when pressure of the fluid to be sealed acts. A sealing device characterized by being a surface. 2. The sealing device according to claim 1, wherein a circumferential groove is provided in the inclined portion. 3. The sealing device according to claim 1, wherein a circumferential groove is provided on a side surface of the biasing ring. 4. The sealing device according to claim 3, wherein a radial groove is provided which connects the inclined portion and the groove provided in the biasing ring. 5. The sliding ring is made of a resin material, and the urging ring is made of a rubber-like elastic body. The sliding ring and the urging ring are provided in contact with or connected to each other. The sealing device according to claim 1, wherein the sealing device is a sealing device.