JP2000055207A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control leakage by providing a flange-shaped fitting, a first and a second seal lip abutting on a sliding face of a shaft in the direction of sealing fluid or in the opposite direction thereto respectively, and a third seal lip supporting the root of the first seal lip. SOLUTION: This sealing device 1 is provided with a flange-shaped fitting part 1a of an annular groove 3b provided in a housing 3, a first seal lip 1b which is extended from the fitting part 1a toward a high pressure side H in the axial direction and abuts on a sliding face of a shaft 2, and a second seal lip 1c which is extended toward the low pressure side L and abuts on the sliding face of the shaft 2, so as to be balancedly held. This device 1 can be thus surely arranged and miniaturized. A third seal lip 1d for supporting the root of the first seal lip 1b is provided so as to suppress the deformation in high pressure. This constitution can hold the pressure resistance and control the appropriate leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sealing device for sealing an annular gap between a housing and a shaft of various devices.

[0002]

2. Description of the Related Art FIG. 2 is a view for explaining a sectional configuration of a sealing device 100 mounted between a rod 101 and a housing 102 having a small radial dimensional allowance according to the prior art. The sealing device 100 is employed, for example, for sealing a pressurized fuel in a fuel pressurizing pump used for an engine that performs fuel injection.

[0003] In FIG.
For example, a high-pressure fluid (gasoline, light oil, or the like) acting as a fluid to be sealed acts in the direction, and the fluid to be sealed that has passed through the sliding portion of the rod guide portion 102a of the housing 102 (marked by X in the drawing) is converted into a rubber-like material. It is sealed by a seal packing 103 made of an elastic body.

The seal packing 103 has a substantially cylindrical shape, and has a groove 103a having a substantially V-shaped or U-shaped cross section formed on an end face on which pressure is applied, and a lip tightening portion formed on the inner and outer peripheral sides of the groove 103a. 103b and 103c are provided.

On the low pressure side L, a seal packing 10 is provided.
Backup ring 10 for preventing overhang of 3
4 is attached.

On the other hand, in recent years, various types of engines that directly inject fuel into a combustion chamber have been developed, and there is a demand for a sealing device having a higher pressure sealing characteristic.

[0007]

However, in the sealing device 100 as shown in FIG. 2, when the shaft 101 and the housing 102 slide at a high speed, there are problems such as a temperature rise and abrasion. However, it has been difficult to improve the durability.

Further, in the structure having the seal lip having elasticity, it is necessary to fit and fix the fitting portion on the housing side and to provide the seal lip extending from the fitting portion with rigidity, but there is a space problem. Therefore, the method of increasing the lip thickness may not be used.

Further, in the above case, oil for lubrication and cooling is often arranged on the low pressure side L, and the amount of oil and fuel leakage is controlled to prevent wear of the shaft and the sealing device. However, if the seal lip itself is deformed due to high pressure, the lip abutment will be solid against the sliding surface of the shaft. Therefore, it is difficult to appropriately control the amount of leakage.

The present invention has been made to solve the above-mentioned problems of the prior art.
It is an object of the present invention to provide a sealing device which has a small space configuration, has high pressure resistance and durability, and can perform appropriate leakage amount control.

[0011]

In order to achieve the above object, according to the present invention, in a sealing device arranged in an annular gap formed by a housing and a shaft, the sealing device is fitted into an annular groove provided in the housing. The flange-shaped fitting portion to be fitted, and the fitting portion floating from the sliding surface of the shaft, extend in the axial direction toward the direction in which high-pressure sealed fluid is present, and extend to the sliding surface of the shaft. A first seal lip that abuts, a second seal lip that extends axially opposite to the first seal lip and abuts a sliding surface of the shaft, and supports a root of the first seal lip And a third seal lip.

[0012] Thereby, the sealing device is connected to the mating portion and the first portion.
In addition, the sealing device can be reliably arranged even when the balance is held by the second seal lip and the radial dimension of the annular gap has no margin.

Since the third seal lip supports the root of the first seal lip, deformation (solid contact, etc.) at high pressure is suppressed, and the followability to the eccentricity of the shaft is improved, so that the pressure resistance is improved. Maintenance and proper leakage control are performed.

[0014] It is also preferable that the third seal lip is provided with a passage for communicating fluid in the axial direction.

The passage of the sealing fluid through the passage enhances the slidability and the durability by proper lubrication of the seal lip.

The fitting portion and each seal lip are integrally formed of a rubber-like elastic body.
It is also preferable to provide a reinforcing ring that is exposed at the end face on the seal lip side and abuts on the annular groove of the housing.

Thus, the posture of the fitting portion of the sealing device is maintained, and the leakage of the sealing fluid from the high pressure side in the fitting portion is effectively prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
It will be described based on.

FIG. 1 is a view for explaining a sectional configuration of a sealing device 1 arranged in an annular gap between a shaft 2 and a housing 3. The sealing device 1 is for the purpose of, for example, sealing a pressurized fuel supplied to a high pressure side H of a shaft 2 which is a plunger reciprocating in an axial direction from a fuel pressurizing pump used for an engine for performing fuel injection. It is what is adopted.

In FIG. 1, fuel (gasoline, light oil, or the like), for example, a high-pressure fluid to be sealed acts in the direction of arrow A1 from the high-pressure side H, and slides on the shaft guide 3a of the housing 3 (marked by X in the figure). ) Is sealed.

The sealing device 1 has a flange-shaped fitting portion 1a fitted into an annular groove 3b provided in the housing 3.
And a fitting portion 1a floating from the sliding surface of the shaft 2.
From the first seal lip 1b extending in the axial direction toward the high-pressure side H and abutting on the sliding surface of the shaft 2, and from the axial direction toward the low-pressure side L and abutting on the sliding surface of the shaft 2. The second seal lip 1c and the first seal lip 1b
And a third seal lip 1d that supports the root of the third seal lip.

The fitting portion 1a and each seal lip 1
b, 1c and 1d are integrally formed of a rubber-like elastic body, and the fitting portion 1a is exposed on the end face 1a1 on the side of the second seal lip 1c and has an annular groove 3 of the housing.
A reinforcing ring 1e abutting on b is provided.

First seal lip 1b of fitting portion 1a
The side is a compression portion 1f made of a rubber-like elastic body, and is configured to be fitted and fixed with a compression allowance with respect to the groove width (opening width in the axial direction) of the annular groove portion 3b.

The low-pressure side L is sealed with oil for lubrication and cooling.

In the sealing device 1 having such a configuration,
Fitting portion 1a and first and second seal lips 1b, 1
c, the sealing device 1 can be reliably disposed even when there is no allowance in the radial dimension of the annular gap,
It is possible to reduce the size of the sealing device.

The third seal lip 1d supports the root of the first seal lip 1b, so that deformation (solid contact, etc.) under high pressure is suppressed, and the followability of the shaft 2 to eccentricity is improved. The pressure resistance is maintained and the leak amount is appropriately controlled.

Due to the structure of the reinforcing ring 1e in the fitting portion 1a, the posture of the fitting portion 1a is maintained and the compression portion 1f is maintained.
Is compressed and closely attached to the annular groove 3b, so that the fitting portion 1
It is possible to effectively prevent the fuel from leaking from the high-pressure side H in a.

The third seal lip 1d may be continuous or discontinuous in the circumferential direction as long as the third seal lip 1d contacts the sliding surface of the shaft 2 to stabilize the first seal lip 1b. A passage provided with a sealed fluid may be provided.

[0029]

According to the present invention described above, the sealing device is balanced by the fitting portion and the first and second seal lips, and there is no allowance in the radial dimension of the annular gap. However, the sealing device can be reliably arranged, and the size of the sealing device can be reduced.

Since the third seal lip supports the root of the first seal lip, deformation (solid contact, etc.) at high pressure is suppressed, and the followability to the eccentricity of the shaft is improved, so that the pressure resistance is improved. Maintenance and proper leakage control are performed.

The reinforcing ring of the fitting portion maintains the position of the fitting portion of the sealing device and effectively prevents leakage of the sealing fluid from the high pressure side in the fitting portion.

[Brief description of the drawings]

FIG. 1 is a sectional configuration explanatory view showing a sealing device according to an embodiment of the present invention.

FIG. 2 is a sectional configuration explanatory view showing a sealing device according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing device 1a Fitting part 1b 1st seal lip 1c 2nd seal lip 1d 3rd seal lip 1e Reinforcement ring 1f Compression part 2 Shaft 3 Housing 3a Shaft guide part 3b Annular groove part

Claims (3)

[Claims] 1. A sealing device disposed in an annular gap formed by a housing and a shaft, wherein the flange-like fitting portion fitted in an annular groove provided in the housing; From the fitting portion in the
A first seal lip extending in a direction in which a high-pressure sealed fluid is present in the axial direction and abutting on a sliding surface of the shaft;
A second seal lip extending toward the opposite side of the first seal lip in the axial direction and abutting against a sliding surface of the shaft;
And a third seal lip for supporting the root of the seal lip. 2. The system according to claim 1, wherein the third seal lip has a passage for communicating fluid in an axial direction.
The sealing device according to claim 1. 3. The fitting portion and each seal lip are integrally formed of a rubber-like elastic body, and the fitting portion is exposed to an end face on a second seal lip side and abuts on an annular groove of a housing. The sealing device according to claim 1, further comprising a ring.