JP2000081149A - Seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep stable sealing property for a long period by continuously providing, in the main lip of a seal member, a ship bottom-like screw projection with height and width increased in the middle and a parallel screw projection having small height and width on the sliding surface of the main lip. SOLUTION: The main lip 11 of a seal member 10 comprises an outside rubber type oil seal with spring, and a spring member 15 is mounted on the circumference of a lip tip 11b. A screw projection 31 is formed of continuous combination of a parallel screw projection 32 and a ship bottom-like screw 33, and it is provided on the sliding surface with inclination, and the lip tip 11b side of the ship bottom-like screw projection 33 is constituted as the parallel screw projection 31. The ship bottom-like screw projection 33 is vertically and laterally extended in the axial middle part, and the parallel screw projection 32 is continued to the lip 11b side thereof. Such a structure of the screw projection 31 is provided with initial sealing property by the self-absorbing effect, and the ship bottom-like screw projection 33 makes contact with the surface of a rotating shaft 3 to exhibit the sealing property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing device which is used, for example, in a rotating portion of various internal combustion engines, a power steering device and the like, and which can seal a sealing fluid such as hydraulic oil.

[0002]

2. Description of the Related Art In rotating parts of various internal combustion engines, power steering devices, and the like, foreign substances such as sludge tend to be generated in a sealing fluid such as hydraulic oil during use, and are used in places where such hydraulic oil is sealed. In the sealing device, foreign matter may enter the sliding surface of the main lip, damage the sliding surface, and impair the sealing performance.

For this reason, as a conventional sealing device of this type, for example, as shown in FIG. 4, a gap between a housing 101 and a shaft 102 is sealed by combining first and second sealing members 103 and 104. There is something.

[0004] In the sealing device 100, a sealing region 107 is formed which is closed by the first and second sealing portions 103 and 104 and the sliding surface of the shaft 102.

[0005] The second sealing member 104 has a sealing fluid side ML to prevent foreign matter from entering the main lip 106.
Is provided with an inclined sub lip 105, which functions as an auxiliary seal.

In order to improve the sealing performance, the main lip 106 has a pump groove 106a formed on the surface of the lip.
Is provided.

[0007]

However, when the shaft 102 is operated using the sealing device 100,
With the rotation of the shaft 102, the pressure in the sealed area 107 is increased by a self-priming effect (pump effect) acting to push back the sealed fluid leaked from the sub lip 105 side of the pump groove 106a of the main lip 106 to the sealed fluid side ML. As a result, a force is applied to the sub lip 105 in a direction away from the shaft 102 (FIG. 5A), and a phenomenon that the sub lip 105 opens may occur (FIG. 5B).

When such a phenomenon occurs, the foreign matter P also enters the sealing area 107 together with the sealing fluid, damaging the sliding surface of the main lip 106, and eventually reduces the sealing performance and may cause leakage. was there.

Therefore, in order to prevent the generation of excessive pressure, the main lip 106 has a structure in which a screw-shaped projection is projected from the lip surface, and the self-priming action of the main lip 106 and the pressure of the sealing area 107 are reduced to a predetermined pressure. It is done to balance.

[0010] However, the screw-like projections protruding from the lip surface have a reduced self-priming function when the projections are worn out by use for a long period of time.
Therefore, it becomes difficult to maintain good sealing performance.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is to provide a main lip having a stable self-priming action and a seal lip arranged on a sealed fluid side. An object of the present invention is to provide a sealing device exhibiting improved sealing properties.

[0012]

In order to achieve the above object, according to the present invention, a housing and a shaft which are coaxially provided and move relatively to each other are fixed to one member of the housing and the shaft. A first seal member having a main lip slidingly contacting the other member of the housing and the shaft, and a fluid to be sealed by the main lip in combination with the first seal member. A second sealing member having a sub-lip slidingly contacting the other member on the side, and an annular sealing region sealed by the main lip and the sub-lip. A boat bottom-shaped screw projection whose height and width are increased in the middle part in the axial direction on the sliding surface, and a height and width of the boat bottom-shaped screw on the lip tip side of the boat bottom-shaped screw projection Characterized by providing substantially continuously constant straight thread protrusions smaller than intermediate portion of the force.

[0013] According to this structure, the boat bottom-shaped screw projection and the parallel screw projection provided on the main lip perform a stable self-priming action even when the main lip is worn, and the main lip and the main lip can be connected to each other. It is possible to suppress the generation of excessive pressure in the annular sealing region formed by the sub-lip on the side of the fluid to be sealed, thereby maintaining stable sealing performance.

[0014]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

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

In FIG. 1, reference numeral 1 denotes an entire sealing device, which is fixed to a housing 2 and seals an annular gap between the rotating shaft 3 and the housing.

The sealing device 1 includes a first seal member 10 having a main lip 11, and a second seal member 20 disposed closer to the sealing fluid ML than the first seal member 10.

The first seal member 10 is a so-called outer peripheral rubber-shaped oil seal with a spring, and is an annular member having a substantially U-shaped cross section that opens to the sealed fluid side ML. The first seal member is
An outer cylindrical portion 12 fitted on the inner periphery of the housing 2, a main lip 11 slidably in contact with the shaft 3 on the inner peripheral side, a rubber elastic body 13, and a metal embedded in the rubber elastic body 13. Ring 1
And 4.

The metal ring 14 has a cylindrical portion 14a and a cylindrical portion 14
Inward flange portion 1 extending inward from the atmosphere side end of a
4b, and the cylindrical portion 14a
Is embedded in the rubber-like elastic body of the outer cylindrical portion 12, and the base end 11 a of the main lip 11 is provided at the inner end of the inward flange portion 14 b.

A spring member 15 is mounted on the outer periphery of the lip tip 11b of the main lip 11 to increase the tightening force.

The base end 11 of the main lip 11
A dust strip 16 extending to the atmosphere side O (anti-sealing fluid side) is provided at a to prevent dust from entering from the atmosphere side O. Further, on the sliding surface 11c of the main lip 11 on the atmosphere side O, a plurality of boat bottom-shaped screw protrusions 31 described later are provided in parallel in order to improve sealing performance.

The second seal member 20 includes a metal ring 21 and a rubber-like elastic sub-lip 22 provided integrally with the inner diameter of the metal ring 21 and slidably and sealingly contacting the rotating shaft 3.

An annular sealing area 7 is formed between the main lip 11 and the sub lip 22. The annular sealing area 7 may be filled with grease as required, and the slidability and sealing property of each lip may be improved.

The metal ring 21 is connected to the outer cylindrical portion 12 of the first seal member.
A cylindrical portion 21a fitted to the inner periphery is formed, and has a flange portion 21b extending radially inward from an edge of the cylindrical portion 21a on the side of the fluid to be sealed. The sub lip 22 is provided at an inner diameter end of the flange portion 21b.

The sub lip 22 is inclined toward the sealing fluid side ML in order to prevent the sludge in the sealing fluid from being caught and to maintain the sealing property of the main lip 11, so that the sealing lip enters the annular sealing area. Restrained.

FIG. 2 is a view for explaining a boat-bottom-shaped screw projection 31 provided on the main lip 11, and FIG.
FIG. 2B is a top view of one screw protrusion 31, and FIG.
It is 1-S1 sectional drawing.

The screw projection 31 is a combination of a parallel screw projection 32 and a boat bottom screw projection 33 continuously provided on the sliding surface 11c at an angle, and the lip tip end 11b side of the boat bottom screw projection 33. Are formed as parallel screw projections 32.

The height and width of the boat bottom screw protrusion 33 are enlarged at an intermediate portion 33a in the axial direction. As shown in FIG. 2B, the axial cross section (S1-S1 cross section) has a bow shape, and is higher toward the middle portion 33a.
The appearance is a semi-elliptic sphere tapering toward both ends in the axial direction, and the intermediate portion 33a is arranged at a position away from the parallel screw projection 32.

The lip tip 1 of the boat bottom screw projection 33
On the 1b side, a parallel screw projection 32 is provided continuously.

The parallel screw projection 32 has a substantially triangular cross section, and the height and width are smaller than the middle part 33a of the boat bottom screw projection 33 and are substantially constant.

In the sealing device 1 having such a configuration, the screw projection 31 provided on the main lip 11 is composed of the parallel screw projection 32 and the boat bottom screw projection 33. The self-priming effect by the effect can provide an initial sealing property.

When the main lip 11 is worn, the boat bottom screw projection 33 comes into contact with the sliding surface of the rotating shaft 3 to exhibit a self-priming effect, thereby exhibiting a sealing property.

The self-priming effect of the screw projection 31 suppresses the generation of excessive pressure in the annular sealing area 7 formed by the main lip 11 and the sub lip 22, thereby maintaining a stable sealing property.

In the manufacturing stage of the first seal member 10, the main lip 11 is used when the rubber material is flowed into the cavity of a molding die having a concave portion for forming the screw protrusion 31 in the cavity and molded. A desired seal lip is obtained by leaving a surplus at the tip and cutting the surplus with a scalpel.

In this case, since the tip of the lip to be knife-cut is a parallel screw projection 32, the workable range at the time of knife cutting can be expanded, and the variation in the position of knife cutting can be absorbed. Performance can be improved.

Further, the screw protrusion may be a screw protrusion 41 as shown in FIGS. 3 (a) and 3 (b).

The screw projection 41 has a configuration in which an intermediate portion 43a whose height and width are maximized is located substantially at the center of the boat bottom screw projection 43 in the axial direction.

[0038]

According to the present invention as described above, the main lip can be provided with a stable self-priming action, and the annular gap between the main lip and the sub lip arranged on the sealed fluid side is excessively large. The generation of pressure is suppressed, and stable sealing properties can be maintained for a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional configuration diagram of a sealing device according to an embodiment.

FIG. 2 is a diagram illustrating a screw protrusion of a main lip according to the embodiment;

FIG. 3 is a view for explaining a screw projection of the main lip according to the embodiment;

FIG. 4 is a schematic configuration diagram of a conventional sealing device.

FIG. 5 is a view for explaining the problem of opening the lip of the conventional sealing device.

DESCRIPTION OF SYMBOLS 1 Sealing device 2 Housing 3 Rotary shaft 7 Annular sealing area 5 Pressure chamber 9 Auxiliary seal 10 First seal member 11 Main lip 12 Outer cylinder part 14 Metal ring 14a Cylindrical part 14b Inward flange part 16 Dustrip 20 Second seal member 21 Metal ring 21a Cylindrical part 21b Flange part 22 Sub lip

Claims (1)

[Claims] 1. A housing, which is coaxially provided and is fixed to one member of a relatively movable housing and a shaft, and seals an annular gap between the housing and the shaft. The other of the housing and the shaft is provided. A first sealing member having a main lip slidingly contacting the member, and a second sealing member combined with the first sealing member and having a sub lip slidingly contacting the other member on the fluid side of the main lip to be sealed.
In a sealing device having a sealing member and an annular sealing region sealed by the main lip and the sub lip, the sliding surface of the main lip of the first sealing member has a height and a width in an intermediate portion in an axial direction. A larger bottom-shaped screw projection and a substantially constant parallel-threaded projection with a smaller height and width smaller than the middle of the bottom-shaped screw projection at the lip tip side of the bottom-shaped screw projection. A sealing device, characterized in that it is provided in a sealing device.