JPH059568Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a sealing device, particularly a reciprocating sealing device.

(Prior Art) Conventionally, as such a sealing device, there is a sealing device 100 shown in FIG. 4. Sealing device 100 is adapted to fit within housing 101 . The sealing device 100 has a lip tip 103 that primarily functions to prevent fluid leakage while being in contact with a reciprocating shaft 102. The lip tip 103 has a wedge-shaped cross section, and the tip strongly presses against the surface of the shaft 102 to seal the fluid. It also has a seal lip 104 that reduces the influence of machine vibrations and pressure fluctuations on the lip tip 103 and maintains a stable contact state of the lip tip 103. The outer periphery of the seal lip 104 secures the sealing device 100 to the housing 101 and at the same time secures the sealing device 100 to the housing 101.
A fitting portion 105 is configured to prevent leakage between the contact surfaces between the inner surface of the sealing device 100 and the outer peripheral portion of the sealing device 100. Seal lip 104 on the inner circumferential side of seal lip 104
A spring 106 is provided to increase the pressing force and maintain the pressing force for a long period of time.

On the other hand, a dust lip 107 is formed on the outer periphery of the seal lip 104 on the atmosphere side to prevent intrusion of external dust.

In such a sealing device 100, when the shaft 102 reciprocates, a sealing lip 104 seals the sealing fluid and a dust lip 107 seals out dust from the outside.

(Problem to be solved by the invention) However, such a conventional sealing device 10
According to 0, the following problems occur.

That is, when the shaft 102 reciprocates, the lip tip 103 of the seal lip 104 strongly presses against the surface of the shaft 102 to seal the fluid. However, as the lip reciprocates many times, a small amount of fluid flows into the lip tip 103.
and the shaft 102 into the chamber 108 between the seal lip 104 and the dust lip 107.
When the amount of fluid that enters the chamber 108 increases, pressure is accumulated inside the chamber 108 . dust trip 107
is formed to prevent dust from entering the chamber 108 from the outside, and is not formed to prevent fluid from leaking from the inside to the outside. There is a problem in that it is not possible to completely prevent fluid from leaking to the outside, and therefore, the fluid that should be sealed leaks from the chamber 108 to the outside, resulting in poor sealing performance.

The present invention was developed in view of the above-mentioned problems, and its purpose is to prevent fluid leaking from the sealed fluid side beyond the tip of the lip from accumulating in the chamber between the tip of the lip and the dust lip. death,
When the moving shaft moves, the O-ring that moves together with the moving shaft and the tapered surface of the seal lip work together to discharge the fluid in the chamber between the tip of the lip and the dust lip to the sealing fluid side, and the sealing fluid to the outside. An object of the present invention is to provide a sealing device that can prevent leakage and improve sealing performance.

(Means for Solving the Problems) The present invention having the above object includes a seal lip that has a tapered inner surface and slides on a reciprocating moving shaft, and a seal lip that is formed on the atmosphere side of the seal lip to prevent external dust from forming. A dust lip that prevents intrusion, and an O-ring that is fitted onto the moving shaft with a predetermined force so that it can move on the moving shaft within a chamber formed by the tapered surface of the seal lip, the inner circumferential surface of the dust lip, and the moving shaft. The fitting with the predetermined force corresponds to when the O-ring moves as the moving shaft moves toward the dust strip and the O-ring comes into contact with the inner peripheral surface of the dust strip. The O-ring stops at the contact position, and as the moving shaft moves toward the seal lip, the O-ring moves, and the O-ring comes into pressure contact with the tapered surface of the seal lip, thereby bringing the seal lip and the moving shaft into contact with each other. The O-ring is fitted with such force that the movement of the O-ring stops when a gap is formed between the O-ring and the O-ring.

(Function) According to the sealing device according to the present invention, the seal lip is fitted onto the moving shaft with a predetermined force so as to be movable on the moving shaft within the space formed by the seal lip, the dust lip, and the moving shaft. It has an O-ring. Therefore, in the pushing process of the reciprocating moving shaft, the moving shaft moves toward the dust strip, but the O-ring also moves together with the moving shaft. If the moving shaft moves further, the O-ring will come into contact with the dust strip and will not move any further. On the other hand, during the pulling process,
The moving shaft moves toward the seal lip, and the O-ring also moves toward the seal lip together with the moving shaft. The inner peripheral surface on the seal lip side has a gently tapered surface, and the movement of the O-ring is gradually braked by this tapered surface, but as the O-ring moves, the seal lip moves upward, and the lip tip of the seal lip moves upward. There is a gap between the axis of movement and the axis of movement. The sealing fluid accumulated on the inner circumferential side of the seal lip is discharged to the fluid side through the O-ring.

Conversely, when the moving shaft moves toward the dust lip again in the pushing process, the O-ring moves toward the dust lip and the seal lip elastically comes into close contact with the moving shaft, causing the fluid on the sealing fluid side to enter the inner periphery of the seal lip. prevent.

In this way, by discharging the sealing fluid to the sealing side using the O-ring during the pulling process of the moving shaft, the sealing fluid accumulates inside the seal lip and prevents it from leaking outside, improving the sealing performance. can be improved.

(Example) The present invention will be explained below based on the illustrated embodiment. Fig. 1 shows a sealing device 1 of the present invention. The sealing device 1 is adapted to be fitted into a housing. The sealing device 1 has a lip tip 3 that mainly functions to prevent fluid leakage while being in contact with a reciprocating moving shaft 2. The tip end 3 of the lip has a wedge-shaped cross section, and the tip strongly presses against the surface of the moving shaft 2 to seal the fluid. It also has a seal lip 4 that reduces the influence of machine vibrations and pressure fluctuations on the lip tip 3 and maintains a stable contact state of the lip tip 3.

The outer periphery of the seal lip 4 constitutes a fitting portion (not shown) that fixes the sealing device 1 to the housing and prevents leakage from the contact surface between the inner surface of the housing and the outer periphery of the sealing device 1. Furthermore, a spring 6 is provided on the inner peripheral side of the seal lip 4 to increase the pressing force of the seal lip 4 and maintain the pressing force over a long period of time.

On the other hand, there is a dust lip 7 on the inner periphery of the seal lip 4 on the atmosphere side that prevents external dust from entering.
is formed.

The inner circumferential surface of the sealing lip 4 forms a gently tapered surface 8 whose diameter decreases toward the sealing fluid side, and the tapered surface 8 extends from the central portion 9 to the tip end 3 of the lip. The tapered surface 8 further extends to the dust strip 7 on the atmosphere side.

Further, an O-ring 10 is disposed within a space formed by the tapered surface 8 of the seal lip 4, the inner circumferential surface of the dust lip 7, and the moving shaft 2. The O-ring 10 is mounted on the moving shaft 2 with a predetermined force so as to be movable on the moving shaft 2.

Here, fitting with a predetermined force means that the O-ring 10 moves as the moving shaft 2 moves toward the dust strip 7 and the O-ring 10 comes into contact with the inner peripheral surface of the dust strip 7. The O-ring 10 stops at this position, and as the moving shaft 2 moves toward the seal lip 4, the O-ring 10 moves and the O-ring 1
The O-ring 10 is fitted with such force that the movement of the O-ring 10 is stopped when the O-ring 10 comes into pressure contact with the tapered surface of the seal lip 4 and a gap is formed between the seal lip 4 and the moving shaft 2.

The sealing device 1 configured in this way operates as follows.

First, the reciprocating moving shaft 2 moves toward the dust strip 7 in the pushing process. As the moving shaft 2 moves toward the dust strip 7, the O-ring 10 attached to the moving shaft 2 also moves toward the dust strip 7 at the same time. Thereafter, the O-ring 10 comes into contact with the dust strip 7 and stops moving.

Next, in the pulling process, the moving shaft 2 moves toward the seal lip 4 side. The O-ring 10 mounted on the moving shaft 2 also moves toward the seal lip 4 side together with the moving shaft 2. As the O-ring 10 moves, the O-ring 10 moves along the tapered surface 8, so that the O-ring 10 moves the seal lip 4 upward (see FIG. 2).

When the seal lip 4 moves upward, the minute distance between the lip tip 3 and the moving shaft 2 increases.
When the O-ring 10 moves on the moving shaft 2, the sealing fluid that has entered the chamber formed by the tapered surface 8 of the sealing lip 4, the inner peripheral surface of the dust lip 7, and the moving shaft 2 is directed toward the sealing lip 4 side. It has the effect of excreting water. The sealing fluid moved by the O-ring 10 is discharged to the sealing fluid side through a small gap between the lip tip 3 and the moving shaft 2.

On the other hand, the movement of the O-ring 10 is gradually restricted by the gently tapered surface 8, and when it becomes unable to resist the pressing force of the seal lip 4, even if the moving shaft 2 continues to move toward the seal lip 4, it remains at that position. Stop. Next, when the pushing process is started again, the moving shaft 2 moves toward the dust strip 7, and the O-ring 10 moves together with the moving shaft 2. As a result, the seal lip 4, which had been pushed up by the O-ring 10, returns to its original position due to its elasticity, and the minute gap becomes smaller, resulting in the movement formed between the lip tip 3 and the moving shaft 2. The oil film formed on the surface of the shaft 2 becomes thinner, and the sealing fluid is sealed well.

Therefore, as the moving shaft 2 moves, the O-ring 10 mounted on the moving shaft 2 moves, and the O-ring 1
0, the sealing lip 4 can be raised to change the distance between the sealing lip 4 and the moving shaft 2, thereby discharging the sealing fluid into the chamber and preventing it from accumulating, thereby improving the sealing performance of the sealing device 1.

Note that the sealing device 1 preferably includes an O-ring 10.
When discharging fluid from the chamber to the sealed fluid side, it is used in a sealing device where the pressure on the sealed side is not high pressure and there is not much difference in pressure between the pressure side and the atmosphere side.

Although the explanation has focused on attaching the O-ring 10 to the moving shaft 2, it is also possible to attach an O-ring having another shape, for example, an X-ring.

(Effects of the invention) The present invention provides a seal lip that is fitted onto a moving shaft with a predetermined force so that it can move on the moving shaft within a chamber formed by the tapered surface of the seal lip, the inner circumferential surface of the dust lip, and the moving shaft. Because it has an O-ring, during the pulling process, the O-ring moves to widen the small gap between the seal lip and the moving shaft, draining the sealing fluid accumulated in the chamber, and during the pushing process. Since the sealing performance can be improved by narrowing the minute gap between the seal lip and the moving shaft, a high-quality sealing device with improved sealing performance can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a partially enlarged longitudinal sectional view of the sealing device of the present invention, Fig. 2 is an explanatory diagram of the operation of the sealing device of the present invention in the pulling process, and Fig. 3 is an explanatory diagram of the operation of the sealing device of the present invention in the pushing process. , FIG. 4 is a longitudinal sectional view of a sealing device according to the prior art. Explanation of symbols, 1...Sealing device, 2...Shaft, 3...
...Rip tip, 4...Seal lip, 6...Spring, 7...Dust lip, 8...Tapered surface, 9...
...Central part, 10...O-ring.

Claims (1)

[Scope of utility model registration request] A seal lip that has a tapered inner surface and slides on a reciprocating moving shaft, a dust lip that is formed on the atmosphere side of the seal lip to prevent external dust from entering, and a tapered surface of the seal lip and an inner circumferential surface of the dust lip. and an O-ring fitted onto the moving shaft with a predetermined force so as to be movable on the moving shaft within a chamber formed by the moving shaft, and the fitting with the predetermined force means that the O-ring can be moved on the moving shaft within a chamber formed by the moving shaft. The O-ring moves as the O-ring moves toward the dust lip, and when the O-ring contacts the inner circumferential surface of the dust strip, the O-ring stops at the contact position, and the seal lip of the moving shaft As the O-ring moves to the side, the O-ring moves, and when the O-ring comes into pressure contact with the tapered surface of the seal lip and forms a gap between the seal lip and the moving shaft, the O-ring stops moving. A sealing device that fits with such force.