JPH09133219A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely prevent the entry of dust even in the case where eccentricity of a shaft occurs by forming a dust lip, which is obliquely projected to the atmospheric air side, so as to contact with the outer peripheral surface of a shaft for sealing in an inner peripheral end of the atmospheric air side of a back-up ring installed in an atmospheric side groove in the inner peripheral surface of a seal part. SOLUTION: A sealing device 1 is formed of a fixing ring part 2 to be installed in the inner peripheral surface of a housing 20 and a seal part 3, which contacts with the outer peripheral surface of a movable shaft 30 for sealing, and the fixing ring part 2 provided between an atmospheric side O and a sealing side M is provided with a reinforcing ring 4, and a fixation side seal part 7 for maintaining the sealing property of the fixing ring part 2 and the inner periphery of the housing 20 is provided in the outer periphery of an axial part 5. The seal part 3 is provided with a main lip 8 made of an elastic member and a buck-up ring 10 for preventing the movement of the main lip 8 to the atmospheric air side O, and an end 10a of the inner peripheral surface 10e of this back-up ring 10 is formed with a dust lip 10b obliquely projected to the atmospheric air side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering rod of an automobile, and more particularly to a sealing device having a backup ring.

[0002]

2. Description of the Related Art A conventional sealing device of this type is shown in FIG. The sealing device 101 includes a sealing portion 103 that is in sealing contact with an outer peripheral surface of a fixed ring portion 102 and a movable shaft 130 that are fitted to the inner peripheral surface of a housing 120.
And is provided between the atmosphere side O and the sealed side M.

The fixed ring portion 102 is provided with a ring-shaped reinforcing ring 104 having an L-shaped cross section, and a fixed side seal portion for maintaining the hermeticity between the fixed ring portion 102 and the inner circumference of the housing 120 on the outer peripheral side of the axial direction portion 105. It is equipped with 107.

The seal portion 103 holds the main lip 108 made of an elastic member and the main lip 108 so that the main lip 108 does not move to the atmosphere side O or warp due to the pressure from the sealing side M, and the main lip 108 has a sealing performance. And a backup ring 110 for keeping the same.

The backup ring 110 is a seal portion 10.
It is fitted in a groove 109 provided on the atmosphere side O side of the inner diameter portion of No. 3.

Further, the sealing device 101 is used so as to be pressed from the atmosphere side O by the seal holder 140 which also serves as a bearing so as not to move to the atmosphere side O when mounted. Therefore, the end of the sealing device 101 on the atmosphere side O is made substantially flat so as to uniformly receive the urging force of the seal retainer 140, and the end of the backup ring 110 on the atmosphere side O of the seal 110 is projected. Direct contact with 140 allows the main lip 108 to move the arrow A
Backup ring 11 even when pushed in the 101 direction
The movement of 0 is reduced as much as possible.

Further, in the backup ring 110, in order to prevent dust from entering the sealed contact portion of the main lip 108 through the gap between the shaft 130 and the seal retainer 140 according to the arrow A102, the inner side of the end 110a is exposed to the atmosphere side. It has a dust lip 110b inclined to O. Therefore, it is possible to prevent the dust on the atmosphere side O from entering and maintain a high sealing performance.

[0008]

However, in the sealing device 101 having the above-described structure, when the shaft 130 is eccentric, the shaft shown in FIG. 5 (a) (FIG. 5 (a) is an enlarged view of the portion D1 in FIG. 4). The shaft 130 moves as indicated by an arrow A103, the outer peripheral surface strongly adheres to the inner peripheral side of the backup ring 110, and urges the dust lip 110b.
It is projected to the atmosphere side O from 0a.

Then, the tip end portion of the dust lip 110b interferes with the inner peripheral end portion 140a of the seal retainer 140. That is, there is a problem in that the tip end portion of the dust lip 110b is sandwiched between the inner peripheral end portion 140a and the shaft 130, which reduces the eccentricity following property and damages the dust lip 110b.

Further, FIG. 5B illustrates the problem in FIG. 5A described above in more detail.
Is present near the dust lip 110b, the shaft 13
It is a figure of the state where 0 was causing eccentricity.

Since the base portion 110d of the conventional dust lip 110b projects directly inward from the inner peripheral surface of the backup ring 110, the entire dust lip becomes parallel to the surface of the shaft when biased by the eccentricity of the shaft. Imitate. Further, the root portion 110d is strongly biased, so that the dust lip may be separated from the surface of the shaft.

Therefore, the tightness of the lip tip portion 110c is reduced or eliminated, and the dust 112 having lost its place easily enters the sealing side. Then, the dust 112 that has entered the sealed side does not return to the outside of the dust lip 110b even if the eccentricity of the shaft subsides, and the main lip 1
08, the sealing performance is degraded.

Further, since the eccentricity of the shaft is generally generated at every rotation of the shaft or periodically due to the vibration, for example, each time the dust lip 110b is tilted, for example, the base portion 11 is formed.
There is a high possibility that stress will be applied to 0d to cause fatigue fracture, and the life of the sealing device 101 may be shortened.

The present invention has been made to solve the above-mentioned problems of the prior art. The purpose of the present invention is to prevent dust from entering even when eccentricity of the shaft occurs. Moreover, it is an object of the present invention to provide a sealing device capable of exhibiting stable dust sealing performance for a long period of time without lowering the eccentricity followability of the dust ring of the backup ring or causing damage.

[0015]

In order to achieve the above object, the present invention seals between two members of a housing and a shaft that move relative to each other, and is fixed to the inner peripheral surface of the housing. A ring portion, a seal portion provided on the inner diameter side of the fixed ring portion with a main lip formed of an elastic material in sealing contact with the outer peripheral surface of the shaft, and a groove formed on the atmosphere side of the inner peripheral surface of the seal portion. In a sealing device equipped with a backup ring for preventing the main lip from falling down to the atmosphere side, an atmosphere is formed so that the inner peripheral end portion of the backup ring on the atmosphere side is in sealing contact with the outer peripheral surface of the shaft. The dust lip is formed so as to incline toward the side, and the position of the tip end portion of this dust lip is set so as to maintain a predetermined gap that does not reach the end portion on the atmosphere side of the backup ring.

It is also preferable to form a recessed groove, which is recessed from the inner peripheral surface of the backup ring, at the root portion protruding from the inner peripheral end portion of the dust lip backup ring on the atmosphere side.

Therefore, in any case, the tip of the dust lip does not interfere with the atmospheric side end of the backup ring, and contact with a fixing member or the like that abuts the atmosphere side of the sealing device is prevented, so that the dust lip of the dust lip is prevented. Decrease in eccentricity tracking and damage do not occur.

Further, the base portion of the dust lip protrudes from the bottom of the concave groove which is recessed from the inner peripheral surface of the backup ring, so that even if the shaft is eccentric, the "slip contact" of the entire dust lip is eliminated. Always maintain dust sealability.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 shows a first embodiment of a sealing device to which the present invention is applied. The sealing device 1 is composed of a fixed ring portion 2 fitted on the inner peripheral surface of the housing 20 and a seal portion 3 which is in sealing contact with the outer peripheral surface of the movable shaft 30, and is provided between the atmosphere side O and the sealing side M. It is provided in.

The fixed ring portion 2 is an annular reinforcing ring 4 having an L-shaped cross section.
On the outer peripheral side of the axial direction portion 5, there is provided a fixed side seal portion 7 formed by an elastic member that maintains the hermeticity between the fixed ring portion 2 and the inner periphery of the housing 20.

The seal portion 3 holds the main lip 8 made of an elastic member and the main lip 8 so that the main lip 8 does not move to the atmosphere side O or warp due to the pressure from the sealing side M, and the main lip 8 has a sealing performance. Backup ring 10
And

The backup ring 10 is fitted in the groove 9 provided on the atmosphere side O side of the inner diameter portion of the seal portion 3. When the shaft 30 is eccentric, in order to improve the eccentricity following property, the outer peripheral surface side of the backup ring 10 is all in contact with the elastic member that constitutes the main lip 8, and the bending of the elastic member is used according to the eccentricity of the shaft 30. And it is possible to move a little in the radial direction.

Further, the sealing device 1 is constructed so that it can be pressed from the atmosphere side O by the seal holder 40 which also serves as a bearing so as not to move to the atmosphere side O when mounted. Therefore, the end of the sealing device 1 on the atmosphere side O is made substantially flat so as to uniformly receive the biasing force of the seal retainer 40, and the end 1 of the backup ring 10 on the atmosphere side O is formed.
By projecting 0a and directly contacting it with the seal retainer 40, the axial movement of the backup ring 10 is minimized even when pushed by the main lip 8 in the direction of arrow A1.

Further, the backup ring 10 has a shaft 3
In order to prevent dust from entering the sealed contact portion of the main lip 8 through the gap between the zero and the seal retainer 40 according to the arrow A2, the backup ring 10 is inclined toward the atmosphere side from the end 10a side of the inner peripheral surface 10e. Protruding dust lip 1
0b. Further, the position of the tip portion 10c of the dust lip 10b is set so as to maintain a predetermined gap G which does not reach the end portion 10a on the atmosphere side of the backup ring.

Therefore, the shaft 30 is eccentric and the dust lip 1
Even if 0b is pressed and bent, the tip portion 10 of the dust lip
c does not interfere with the atmospheric side end 10a of the backup ring, and therefore the seal retainer 40 is in contact with the atmospheric side of the sealing device.
Since the contact between the dust lip and the like is prevented, the deterioration of the eccentricity followability and the damage due to the dust lip being sandwiched between the seal retainers 40 do not occur.

(Second Embodiment) FIG. 2 is a diagram for explaining a second embodiment to which the present invention is applied. The second embodiment is different from the above-described first embodiment only in the backup ring 50, and other same components are denoted by the same reference numerals and are the same as the first embodiment. It will be treated as an item and its explanation will be omitted.

The backup ring 50 of this embodiment
Is a groove 50f that is recessed from the inner peripheral surface 50e of the backup ring 50 at the root of the dust lip 50b.

Therefore, the root portion of the dust lip 50b has a structure protruding from the bottom of the recessed groove 50f which is recessed from the inner peripheral surface 50e of the backup ring 50.

FIG. 2 (a) is a view showing a state where the shaft 30 is not eccentric, and the dust lip 50b is in sealing contact with the outer peripheral surface of the shaft at a predetermined interference. Further, FIG. 2B shows the shaft 3
0 is eccentric in the direction of arrow A3, and its outer peripheral surface is in contact with the inner peripheral surface 50e of the backup ring 50.

As can be seen from FIG. 2 (b), even if the shaft is eccentric, so-called "sticky contact" does not occur on the entire side of the dust lip 50b that abuts the outer peripheral surface of the shaft, and the tip end portion does not occur. 50c is in sealing contact with the outer peripheral surface of the shaft without impairing the tightening force, and always maintains the dust sealing property.

The outer peripheral surface of the shaft is a dust lip 50b.
Since it does not come into direct contact with the base of the base, the bending stress applied to the base is reduced and damage to the base due to fatigue is prevented.

(Third Embodiment) FIG. 3 is a diagram showing a third embodiment. The sealing device 64 shown in this figure extends the radial portion 66 of the reinforcing ring 64 to the vicinity of the outer peripheral surface of the shaft 3 as a fixing method when the backup ring 70 is pressed by the main lip 68 in the direction of arrow A4, and the end thereof is End of the backup ring 70 on the atmosphere side O on the sealed side M side
0a is in contact.

The tip portion 7 of the dust lip 70b in this case
The position of 0c is also set so as to maintain a predetermined gap G that does not reach the end 70a on the atmosphere side of the backup ring, as in the first embodiment.

Therefore, the shaft 30 is eccentric and the dust lip 7
Even if 0b is pressed and bent, the tip portion 70 of the dust lip
c does not interfere with the atmospheric side end 70a of the backup ring, and therefore the reinforcing ring 64 located on the atmospheric side of the sealing device 61.
Since the contact of the dust lip with the radial portion 66 is also prevented, the deterioration of the eccentricity followability and the damage due to the dust lip being sandwiched between the radial portions 66 do not occur.

[0035]

According to the present invention having the above-described structure and operation, contact between the dust lip formed on the backup ring and another component such as a seal retainer that abuts the atmosphere side of the sealing device is prevented, and the dust is prevented. Prevents deterioration and damage of strip eccentricity.

Further, by forming a concave groove at the base of the dust lip, the dust seal property can be always maintained well without impairing the tightening force at the tip of the dust lip, and the fatigue damage of the dust lip is prevented. It is possible to exhibit stable dust sealing performance over a long period of time.

[Brief description of the drawings]

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

FIG. 2 is an enlarged explanatory view of a backup ring of a sealing device to which the present invention is applied (Embodiment 2).

FIG. 3 is an explanatory cross-sectional view of a sealing device to which the present invention is applied (Embodiment 3).

FIG. 4 is a cross-sectional explanatory view of a conventional sealing device.

FIG. 5 is a view for explaining the operation of the dust lip of the conventional sealing device.

[Explanation of symbols]

 1 Sealing device 2 Fixed ring part 3 Seal part 4 Reinforcement ring 5 Axial part 7 Fixed side seal part 8 Main lip 9 Groove 10 Backup ring 10a End part 10b Dustrip 10c Tip part 10e Inner peripheral surface 20 Housing 30 Shaft 40 Seal retainer 50 backup ring 50b dust lip 50c tip part 50e inner peripheral surface 50f concave groove A1, A2, A3, A4 arrow O atmosphere side M sealed side

Claims (2)

[Claims] 1. A seal for sealing between two members of a housing and a shaft that move relative to each other, a fixed ring portion mounted on an inner peripheral surface of the housing, and an inner peripheral surface of the fixed ring portion on an outer peripheral surface of the shaft. A seal portion having a main lip formed of an elastic material that makes a sealing contact, and a backup ring mounted in a groove formed on the atmosphere side of the inner peripheral surface of the seal portion to prevent the main lip from falling down to the atmosphere side. In the sealing device provided with, a dust lip that is inclined and protrudes toward the atmosphere side is formed at an inner peripheral end portion of the backup ring on the atmosphere side so as to make sealing contact with an outer peripheral surface of the shaft, and a tip of the dust lip. The sealing device is characterized in that the position of the portion is set so as to maintain a predetermined gap that does not reach the end of the backup ring on the atmosphere side. 2. The recessed groove, which is recessed from the inner peripheral surface of the backup ring, is formed in the root portion protruding from the inner peripheral end portion of the dust lip backup ring on the atmosphere side. The sealing device described.