JPH07239042A - Sealing device - Google Patents

Abstract

PURPOSE:To extend the life of a sealing device having two or more seal lips by preventing losses in sealing performance due to imperfect fluid lubrication on the sliding surface of each seal lip. CONSTITUTION:A sealing device 10, which has at least two seal lips for sealing the space between two members that rotate relative to and concentric with each other, is provided with a supply passage 7T by which a sealed space 2 surrounded by the two seal lips, i.e., main 3 and auxiliary 1 seal lips and by a shaft 15 is communicated with a sealed space 17 in which a fluid to be sealed locates so as to supply the fluid in the sealed space 17 into the sealed space 2, and the sealing device is also provided with a supply valve 7 for opening and closing the supply passage 7T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device for sealing between two members which are concentrically rotated relative to each other.

[0002]

2. Description of the Related Art As a conventional sealing device of this type, there is a sealing device 110 whose sectional view is shown in FIG. Sealing device 1
Reference numeral 10 is an annular sealing device having a reinforcing metal wheel 111 having an L-shaped cross section, and formed by baking a rubber-like elastic body on the inner and outer circumferences of the metal wheel 111. Reference numeral 108 denotes a fitting portion that is circumscribed in the housing hole 116, and 106 is a seal lip portion that slidably inscribes in the shaft 115. Furthermore, the seal lip is a dust lip 1 that prevents the ingress of external dust.
The main seal lip 103 and the sub-seal lip 101 that prevent fluid from leaking while sliding on the shaft 115 that rotates with the shaft 05 and the spring spring 109 that enhances the force for pressing the seal lip portion against the shaft 115.

Before assembly and use, the main seal lip 103 and the main seal lip 101 are lubricated to lubricate the main seal lip 103 and the sub seal lip 101.
And, the gap provided between the dust lip 105 and the main seal lip 103 is filled with initial grease,
It is incorporated in the shaft 115.

In the sealing device having two or more seal lips as in the above-mentioned conventional example, the sub-seal lip 101 on the side which seals the fluid first prevents the fluid from leaking and at the same time protects from fine foreign matter in the sealed fluid. Outer main seal lip 103
It also has the function of protecting. Thus, by having two or more main lips, it is considered to maintain a stable contact state and a stable sealing action.

[0005]

However, in such a conventional example, the following problems have occurred.
In the main seal lip 103, its lubrication action depends only on the initially filled grease filled as described above when the shaft is incorporated into the shaft (the sub seal lip 10
If the shaft is rotated for a long time and the sealing device is made to function because the fluid is almost completely sealed with 1), the initial sealed grease is deteriorated due to heat, and the pulsating pump effect due to evaporation and vibration causes the sealed grease to be sealed to the sealed side. Due to a phenomenon such as movement, the sliding surface of the main seal lip 103 cannot be sufficiently lubricated, the sliding surface of the seal lip portion is thermally hardened, cracks are generated, and sludge is attached. The sealing performance of the sealing device is impaired and the service life is shortened.

The present invention has been made in order to solve the above-mentioned problems of the prior art. The object of the present invention is to provide a sealing device having two or more seal lips and to perform fluid lubrication on the sliding surface of the main seal lip. This is to prevent loss of sealing performance due to defects and extend the service life.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention seals between two members that rotate concentrically relative to each other, and is an annular device body fixed to one member. And a sealing device having at least two seal lips provided on the main body of the device and slidably sealingly contacting the other member, the sealed space being surrounded by the two seal lips and the other member. And a supply passage for communicating the fluid to be sealed with the fluid side space to supply the fluid in the fluid to be sealed side space to the sealed space, and a supply valve for opening and closing the supply passage.

The two seal lips are composed of a main seal lip and a sub seal lip extending from the tip of the main seal lip, and the supply passage and the supply valve are formed in the sub seal lip.

Further, the supply valve is a check valve that opens at a predetermined pressure difference, and is configured to automatically supply the fluid to be sealed by opening it by the negative pressure generated in the sealed space during rotation.

[0010]

In the sealing device configured as described above,
Even if the lubricating fluid flows out through the gap of the fluid lubrication film formed on the sliding surface of each seal lip, sliding the seal lip by opening the supply valve and introducing the fluid to be sealed into the sealed space through the supply passage. Maintains fluid lubrication on the moving surface.

If the two seal lips are composed of the main seal lip and the small lip extending from the tip of the main seal lip, the sub seal lip protects the main seal lip from fine foreign matters in the sealing fluid, and the supply valve described above. A fluid lubrication state is maintained by supplying the fluid from.

The supply valve is used as a check valve to supply the lubricating fluid through the valve by utilizing the negative pressure generated during rotation.

[0013]

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

FIG. 1 is a sectional view of a sealing device 10 embodying the present invention.

The sealing device 10 is a ring-shaped sealing device having a reinforcing metal ring 11 having an L-shaped cross section as a device body, and a rubber-like elastic body is sintered and formed on the inner and outer circumferences of the metal ring 11. .

Reference numeral 8 is a fitting portion which is circumscribed in the housing hole 16, and 6 is a seal lip portion which is slidably inscribed in the shaft 15. The seal lip portion has a plurality of seal lips, and a dust lip 5 that prevents invasion of dust from the outside as a seal lip and a main seal lip 3 and a sub seal lip that prevent fluid leakage while sliding on the rotating shaft 15. 1 and a spring spring 9 that enhances the force of pressing the seal lip portion against the shaft 5.

Further, in the hermetically sealed spaces 4 and 2 formed between the dust lip 5, the main seal lip 3, the main seal lip 3 and the sub seal lip 1, the main seal lip 3 and the sub seal lip 3 are provided before the start of assembly and use. For the purpose of lubrication No. 1, the initial grease is filled and incorporated in the shaft 15.

In the present embodiment, the left side where the dust lip 5 is provided in FIG. 1 is the non-sealing target fluid side (the non-sealing space 18) and the right side where the main and sub seal lips are provided is oil and water. , A structure having a sealed space 17 for sealing a fluid to be sealed such as chemicals. Further, a supply passage 7T for supplying the sealed fluid in the sealed space 17 to the sealed space 2 and a supply valve 7 for opening and closing the supply passage, which are features of the present invention, are provided. The position where the supply passage 7T and the supply valve 7 are provided can be provided at a predetermined position for achieving the above object.

In this embodiment, the auxiliary seal lip 1 is constructed so as to extend from the tip of the main seal lip 3, and the supply passage 7T and the supply valve 7 are provided in the auxiliary seal lip 1.

The main portion A of the supply passage 7T and the supply valve 7 in this case is shown in FIG. The supply valve 7 is integrally formed on the sub seal lip 1, and has a C-shaped valve as shown in FIG. 3A when the supply valve 7 is viewed from the direction of the arrow in the figure. . Variations of the valve shape are shown as examples in FIGS. 3 (b) to 3 (d).

The sealed fluid flows into the sealed space 2 through the supply valve 7, and the fluid lubrication state of the sliding surface of the main seal lip can be maintained.

FIG. 4 is a diagram showing the circulation of the sealing fluid through the supply valve 7 into the sealed space 2 and back to the sealed space 17. That is, the supply valve 7 is a check valve that opens at a predetermined pressure difference, and the negative pressure generated in the sealed space 2 when the shaft 15 rotates causes the supply valve 7 to open as shown in the drawing and seal in the direction indicated by arrow B A fluid is supplied and, if necessary, circulated to the sealed space 17.

FIG. 5 shows the operating state of the supply valve.

The structure of FIG. 5 (a) has a C-shaped valve similar to a diaphragm, and in the state where the shaft 15 is stopped without rotating, the sealed space 2 and the sealed space 1 formed between the seal lips are formed.
There is no pressure difference with the valve 7, and the valve is closed at the position shown by the solid line in the AA cross section. When the shaft 15 rotates, the pressure in the sealed space 2 between the seal lips drops, and a pressure difference occurs between this and the sealed space 17, the valve opens to the position indicated by the broken line A'in the AA cross section. On the contrary, even if the pressure in the sealed space 2 between the seal lips rises, the valve does not open above the position shown by the solid line and has a check valve function.
The example in FIG. 5B also has the same configuration and operation as in FIG.

FIGS. 5 (C) and 5 (D) have a valve similar to a diaphragm having a cross shape or a notch divided into six parts, and have the same function as the valve of (A). However, when the pressure in the sealed space 2 between the seal lips rises, it may move a little higher than the position shown by the solid line where there is no pressure difference, as shown by the broken lines C "and D". I don't know, but each valve is closed and has the function of a check valve.

In order to effectively operate the supply valve 7, FIG.
As in (a), (b), and (c), a predetermined groove for generating a negative pressure effect can be provided on the sliding surfaces of the main and auxiliary seal lips that slide on the shaft 15. This groove has a screw effect of pushing out a lubricating fluid forming a thin lubricating film on the sliding surfaces of the main and sub seal lips with the shaft in a desired direction by the rotation of the shaft 15 due to a screw effect, and an outflow space of the lubricating fluid. A negative pressure is generated in the sealed space 2 on the side.

With this structure, when the shaft 15 rotates,
A proper amount of lubricating fluid is always supplied to the sealed space 2 through the supply valve 7.

[0028]

EFFECTS OF THE INVENTION The present invention has the above-described structure and operation. Even if the lubricating fluid flows out through the gap of the fluid lubrication film formed on the sliding surface of each seal lip, the supply valve is opened and sealed. By introducing the target fluid into the sealed space through the supply passage, the fluid lubrication state of the sliding surface of the seal lip is maintained, loss of the sealing performance of the seal lip is prevented, and a long life is achieved.

If the two seal lips are composed of a main seal lip and a small lip extending from the tip of the main seal lip, the sub seal lip protects the main seal lip from fine foreign matters in the sealing fluid, and the above supply valve. By supplying the fluid from above, the sealing performance of the main seal lip can be maintained while maintaining the fluid lubrication state.

If the supply valve is used as a check valve to supply the lubricating fluid by utilizing the negative pressure generated at the time of rotation, an appropriate amount of the lubricating fluid is always supplied at the time of rotation, and there is a risk of running out of lubrication. Furthermore, the loss of the sealing performance of the seal lip is reduced, and the service life is extended.

[Brief description of drawings]

FIG. 1 is a sectional view of a sealing device to which the present invention is applied.

FIG. 2 is an enlarged view of a main part of a supply valve.

FIG. 3 is a diagram of variations in valve shape.

FIG. 4 is a cross-sectional view for explaining the function of the supply valve.

FIG. 5 is a diagram of a variation of a supply valve (check valve).

FIG. 6 is a view showing a variation of the thread groove provided on the seal lip.

FIG. 7 is a cross-sectional view of a conventional sealing device.

[Explanation of symbols]

 1,101 Sub seal lip 2,4 Sealing space 3,103 Main seal lip 5 Duslip 6,106 Seal lip part 7 Supply valve 7T Supply passage 8,108 Fitting part 9,109 Spring spring 10,110 Sealing device 11,111 Reinforcing metal ring 13 Flow direction of sealed fluid 15 Shaft 16 Housing hole 17 Sealed space 18 Non-sealed space

Claims (3)

[Claims] 1. An annular device main body fixed to one member for sealing between two members that rotate concentrically relative to each other, and a tip provided on the device main body slides with respect to the other member. In a sealing device including at least two seal lips that freely and sealingly contact each other, a sealing space surrounded by the two seal lips and the other member and a sealing target fluid side space communicate with each other, and And a supply valve for opening and closing the supply passage. 2. The two seal lips are composed of a main seal lip and a sub seal lip extending from the tip of the main seal lip, and the supply passage and the supply valve are formed in the sub seal lip. Sealing device. 3. The supply valve is a check valve that opens at a predetermined pressure difference, and is configured to automatically open and supply the fluid to be sealed by the negative pressure generated in the sealed space during rotation. Or the sealing device according to 2.