JP2013072472A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device exhibiting a sealing function even under a low fluid pressure while restraining a sliding torque lower.SOLUTION: The sealing device includes first and second seal lips 12 and 13 having outer peripheral faces 12a and 13a consisting of tapered faces expanding outward from an axial direction respectively. An outer diameter of each of front lip ends 12b and 13b is larger than an inner diameter of a shaft hole 301 in which a shaft 200 in a housing 300 is inserted under no action of an external power. A seal ring 10 is attached inside a circular groove 210. Under no action of a fluid pressure, the first and second seal lips 12 and 13 rest inclining inside in an axial direction respectively. Thereby the constitution provides each of the front lip ends 12b and 13b of the first and second seal lips 12 and 13 with a linear contact with the inner peripheral face of the shaft hole 301.

Description

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

  In ATs and CVTs for automobiles, a seal ring for sealing an annular gap between a relatively rotating shaft and a housing is provided in order to maintain hydraulic pressure. In the case of a general seal ring, it is mounted in an annular groove provided on the outer periphery of the shaft, and slidably contacts each of the inner peripheral surface of the shaft hole of the housing through which the shaft is inserted and the side surface of the annular groove. The annular gap between the shaft and the shaft hole of the housing is configured to be sealed.

  In the seal ring used in the above applications, it is required that the sliding torque is sufficiently low. Therefore, conventionally, in a state where the engine of the automobile is applied and the hydraulic pressure is high, the seal ring is brought into close contact with the inner peripheral surface of the shaft hole and the side surface of the annular groove to sufficiently hold the hydraulic pressure, In a state where no hydraulic pressure is applied due to the stop, the seal ring is configured to be separated from the inner peripheral surface of the shaft hole and the side surface of the annular groove.

  However, in the case of the seal ring configured as described above, the seal function is not exhibited in a state where no hydraulic pressure is applied. In a no-load state where the pump is stopped (for example, when idling is stopped), the oil sealed by the seal ring returns to the oil pan without being sealed, and the oil near the seal ring disappears. Therefore, when the engine is started (restarted) from this state, the operation is started in a state where there is no oil near the seal ring and there is no lubrication.

JP 2010-265937 A Japanese Patent No. 4143786

  An object of the present invention is to provide a sealing device capable of exerting a sealing function even when the fluid pressure is low while keeping the sliding torque low.

  The present invention employs the following means in order to solve the above problems.

That is, the sealing device of the present invention is
Fluid pressure in a region to be sealed is mounted in an annular groove provided on the outer periphery of the shaft and configured to seal the annular clearance between the relatively rotating shaft and the housing so that the fluid pressure changes. In a sealing device that holds
A resin seal ring mounted in the annular groove;
The seal ring is
A cylindrical portion in close contact with the outer circumferential surface of the bottom of the annular groove;
A first seal lip extending outward from one end of the cylindrical portion;
A second seal lip extending outward from the other end of the cylindrical portion;
With
The outer peripheral surfaces of the first seal lip and the second seal lip are both formed by a tapered surface whose diameter increases toward the outside in the axial direction, and an external force acts on the outer diameter of the outer edge in the axial direction. In a state where the shaft in the housing is inserted larger than the inner diameter of the shaft hole,
When the seal ring is mounted in the annular groove and no fluid pressure is applied, both the first seal lip and the second seal lip are inclined inward in the axial direction. The outer edges in the axial direction of the outer peripheral surfaces of the lip and the second seal lip are both configured to be in line contact with the inner peripheral surface of the shaft hole.

  According to the present invention, the lip tips (the outer edges in the axial direction) of the first seal lip and the second seal lip are on the inner peripheral surface of the shaft hole even when the fluid pressure in the region to be sealed is not acting. It will be in the state which carried out the line contact and can exhibit a sealing function. Therefore, the fluid pressure can be maintained immediately after the fluid pressure in the seal target region starts to increase. In addition, when the fluid pressure is applied from either the axial direction or the lip tip is in line contact, the seal lip on the side on which the fluid pressure acts is deformed so as to fall inward, and the inside of the shaft hole The sliding torque can be effectively reduced in combination with the fact that it does not contact the peripheral surface (or the contact pressure decreases).

  It is good to provide the pressing member with which it mounts | wears with the outer peripheral side of the said cylindrical part, and presses the inner peripheral surface of this cylindrical part toward the groove bottom of the said annular groove.

  Thereby, it is possible to prevent the seal ring from rotating relative to the shaft more reliably.

  The seal ring is obtained by subjecting an annular material made of PTFE to a bending process by heat press, and both end surfaces of the material are respectively outer peripheral surfaces of a first seal lip and a second seal lip. It ’s good.

  Thereby, manufacture of a seal ring can be made easy.

  As described above, according to the present invention, the sealing function can be exhibited even when the fluid pressure is low while the sliding torque is kept low.

It is a partially broken sectional view of the sealing device concerning the example of the present invention. It is typical sectional drawing which shows the raw material (intermediate product) before manufacture of the seal ring which concerns on the Example of this invention. It is a typical sectional view showing the wearing state (state where fluid pressure is not acting) of the sealing device concerning the example of the present invention. It is typical sectional drawing which shows the mounting state (state in which fluid pressure is acting) of the sealing device which concerns on the Example of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. . The sealing device according to the present embodiment is used for sealing an annular gap between a relatively rotating shaft and a housing in order to maintain hydraulic pressure in a transmission such as an AT or CVT for an automobile. It is used.

(Example)
A sealing device according to an embodiment of the present invention will be described with reference to FIGS.

<Configuration of sealing device>
In particular, the configuration of the sealing device according to the embodiment of the present invention will be described with reference to FIGS. The sealing device 100 according to the present embodiment is attached to an annular groove 210 provided on the outer periphery of the shaft 200 and seals an annular gap between the relatively rotating shaft 200 and the housing 300. As a result, the sealing device 100 maintains the fluid pressure in the region to be sealed configured so that the fluid pressure (hydraulic pressure in this embodiment) changes. Here, in this embodiment, the fluid pressures on both the left and right sides in FIG. 3 are configured to change. When the automobile engine is stopped, the fluid pressure in the seal target area is low and no load is applied. When the engine is started, the fluid pressure in the seal target area increases.

  The sealing device 100 according to the present embodiment includes a seal ring 10 made of resin (more specifically, PTFE (polytetrafluoroethylene)) and a rubber O-ring 20 as a pressing member.

  The seal ring 10 includes a cylindrical portion 11 that is in close contact with the outer peripheral surface of the groove bottom 211 of the annular groove 210, a first seal lip 12 that extends outward from one end portion of the cylindrical portion 11, and the other end portion of the cylindrical portion 11. And a second seal lip 13 extending outward from the outer side.

  The outer peripheral surface 12a of the first seal lip 12 is configured by a tapered surface that increases in diameter toward the outside in the axial direction. The outer diameter of the lip tip 12b of the first seal lip 12 (the outer edge of the outer peripheral surface 12a in the axial direction) is such that the shaft 200 in the housing 300 is inserted when no external force is applied. It is configured to be larger than the inner diameter. Similarly, the outer peripheral surface 13a of the second seal lip 13 is also formed by a tapered surface whose diameter increases toward the outside in the axial direction, and the outer diameter of the lip tip 13b is in a state where no external force is applied. The inner diameter of the shaft hole 301 is larger.

  When the seal ring 10 is mounted in the annular groove 210 and no fluid pressure is applied, both the first seal lip 12 and the second seal lip 13 are inclined inward in the axial direction. (See FIG. 3). At this time, the lip ends 12 b and 13 b of the first seal lip 12 and the second seal lip 13 are both configured to be in line contact with the inner peripheral surface of the shaft hole 301. In this embodiment, as shown in FIG. 1, the first seal lip 12 and the second seal lip 13 are not inclined inward in the axial direction in the state before the mounting, and the shaft hole is not mounted. It is configured to tilt inward by receiving a force from the inner peripheral surface of 301. However, it is also possible to adopt a configuration in which both the first seal lip 12 and the second seal lip 13 are previously inclined to the inner side in the axial direction in a state before being mounted.

  The O-ring 20 is attached to the outer peripheral side of the cylindrical portion 11. The cylindrical portion 11 is tightened from the outer peripheral side by the elastic restoring force of the O-ring 20, and the inner peripheral surface 11 a of the cylindrical portion 11 is pressed toward the groove bottom 211 of the annular groove 210.

<Seal ring manufacturing method>
A method for manufacturing the seal ring 10 according to the present embodiment will be described with reference to FIG. In this embodiment, PTFE is used as a molding material, and an annular material 10X (intermediate product) is molded by a generally known mold molding technique as shown in FIG. And it is set as the state which bent both sides of this raw material 10X in the A direction and the B direction in the figure by performing the bending process by a heat press. Thereby, the seal ring 10 shown in FIG. 1 can be obtained. Here, as shown in FIG. 2, both end surfaces of the material 10 </ b> X are configured with tapered surfaces that reduce in diameter toward the tip. Thus, by bending both sides of the material 10X, the outer peripheral surfaces 12a and 13a of the first seal lip 12 and the second seal lip 13 can be tapered surfaces as described above.

<Mechanism when using sealing device>
In particular, with reference to FIG. 4, a mechanism during use of the sealing device according to the embodiment of the present invention will be described. In this embodiment, the fluid pressure on both the left and right sides in FIG. 4 is configured to change. 4A shows a state in which the fluid pressure P is applied from the right side (a state in which the fluid pressure is higher in the right side than in the left side), and FIG. 4B shows a state in which the fluid pressure P is applied from the left side ( The left side shows a higher fluid pressure than the right side).

  As described above, in this embodiment, when the seal ring 10 is mounted in the annular groove 210 and no fluid pressure is applied, the first seal lip 12 and the second seal lip 13 are both axial. It is comprised so that it may be in the state inclined inside. Therefore, when the fluid pressure is applied, the seal lip on the side on which the fluid pressure is applied is deformed so as to fall inward and does not contact the inner peripheral surface of the shaft hole 301 or even if it is in contact, the contact pressure decreases. That is, as shown in FIG. 4A, when the fluid pressure P is applied from the right side, the second seal lip 13 is deformed so as to fall inward, and the lip tip 13b is separated from the inner peripheral surface of the shaft hole 301. (Or contact pressure decreases). On the other hand, since the first seal lip 12 on the side opposite to the side on which the fluid pressure P acts receives a force toward the outside in the axial direction, the lip tip 12b is against the inner peripheral surface of the shaft hole 301. The contact state is stably maintained. When the fluid pressure P is applied from the left side as shown in FIG. 5B, the first seal lip 12 is deformed so as to fall inward, and the lip tip 12b is separated from the inner peripheral surface of the shaft hole 301. (Or contact pressure decreases). The second seal lip 13 on the side opposite to the side on which the fluid pressure P acts receives a force directed outward in the axial direction, so that the lip tip 13b is in contact with the inner peripheral surface of the shaft hole 301. The state is stably maintained.

<Excellent point of sealing device according to this embodiment>
According to the sealing device 100 according to the present embodiment, the lip tips 12b and 13b of the first seal lip 12 and the second seal lip 13 are within the shaft hole 301 even when the fluid pressure in the region to be sealed is not acting. It becomes the state which carried out the line contact to the surrounding surface, and can exhibit a sealing function. As a result, the fluid pressure can be maintained immediately after the fluid pressure in the seal target region starts to increase. Therefore, when the accelerator is depressed from the state where the engine is stopped, the engine is started, so that the hydraulic pressure can be held immediately after the hydraulic pressure in the seal target region starts to increase.

  Further, when the lip tips 12b and 13b are in a line contact state and when fluid pressure is applied from any of the axial directions, the seal lip on the side on which the fluid pressure is applied is deformed so as to fall inward, and the shaft In combination with the fact that the inner surface of the hole 301 is not contacted (or the contact pressure decreases), the sliding torque can be effectively reduced. Along with this, heat generation due to sliding is suppressed, and it can be suitably used even in a high temperature and high pressure environment.

In the present embodiment, the seal ring 10 is provided on the outer peripheral side of the cylindrical portion 11 and includes an O-ring 20 that presses the inner peripheral surface 11 a of the cylindrical portion 11 toward the groove bottom 211 of the annular groove 210. Is adopted. Thereby, it is possible to prevent the seal ring 10 from rotating relative to the shaft 200 more reliably. More specifically, the shaft 200
Is rotated together with the shaft 200, the sealing device 100 is also rotated. There is no relative rotation between the shaft 200 and the sealing device 100, and no sliding portion is generated. Therefore, it is possible to make the sliding portion only the lip ends 12b and 13b of the first seal lip 12 and the second seal lip 13 and the inner peripheral surface of the shaft hole 301, and the sliding torque can be effectively reduced. it can.

  Furthermore, since the seal ring 10 is obtained by subjecting the annular material 10X made of PTFE to a bending process by heat press, the manufacture of the seal ring 10 is easy.

(Other)
In the seal ring 10 in the above embodiment, a configuration in which a cutting portion (abutment) is provided at one place in the circumferential direction may be employed. By adopting such a configuration, the mountability of the seal ring 10 can be improved. Even in the case where the cut portion is provided, the seal ring 10 is fastened to the inner peripheral side by the O-ring 20, so that deterioration in quality can be sufficiently suppressed. Moreover, a well-known technique can be applied suitably about the structure of a cutting part. Examples include straight cut and bias cut.

  In the said Example, although the case of the rubber-made O-ring 20 was mentioned as an example as a press member, it is not restricted to this. That is, as the pressing member, other members may be employed as long as the inner peripheral surface 11a of the cylindrical portion 11 of the seal ring 10 can be pressed toward the groove bottom 211 of the annular groove 210. For example, a rubber square ring (ring having a rectangular cross section), a metal annular spring (garter spring), or the like can be used.

  Moreover, in the said Example, the seal ring 10 is made into the axis | shaft 200 by sticking the inner peripheral surface 11a of the cylindrical part 11 in the seal ring 10 to the groove bottom 211 of the annular groove 210, and providing a pressing member (O-ring). The structure which prevents it from rotating relatively with respect to is shown. However, if it is possible to prevent relative rotation with respect to the shaft 200 by only the adhesion force of the cylindrical portion 11 without providing a pressing member depending on the use environment or the like, the pressing member (O-ring) Need not be provided. However, in this case, the seal ring needs to have an endless shape without providing a cutting portion (abutment).

  Moreover, in the said Example, although the case where the seal ring 10 was manufactured by performing the bending process by the heat press with respect to the cyclic | annular raw material 10X was demonstrated, as the seal ring 10 is manufactured by a cutting process. You can also

  Further, in the above embodiment, the case where the fluid pressures on both the left and right sides in FIGS. 3 and 4 are configured to change is shown, but even when the fluid pressure on only one side changes, the above It is possible to apply the sealing device 100.

DESCRIPTION OF SYMBOLS 10 Seal ring 10X Material 11 Cylindrical part 11a Inner peripheral surface 12 1st seal lip 13 2nd seal lip 12a, 13a Outer peripheral surface 12b, 13b Lip tip 20 O-ring 100 Sealing device 200 Shaft 210 Annular groove 211 Groove bottom 300 Housing 301 Shaft Hole

Claims (3)

Fluid pressure in a region to be sealed is mounted in an annular groove provided on the outer periphery of the shaft and configured to seal the annular clearance between the relatively rotating shaft and the housing so that the fluid pressure changes. In a sealing device that holds
A resin seal ring mounted in the annular groove;
The seal ring is
A cylindrical portion in close contact with the outer circumferential surface of the bottom of the annular groove;
A first seal lip extending outward from one end of the cylindrical portion;
A second seal lip extending outward from the other end of the cylindrical portion;
With
The outer peripheral surfaces of the first seal lip and the second seal lip are both formed by a tapered surface whose diameter increases toward the outside in the axial direction, and an external force acts on the outer diameter of the outer edge in the axial direction. In a state where the shaft in the housing is inserted larger than the inner diameter of the shaft hole,
When the seal ring is mounted in the annular groove and no fluid pressure is applied, both the first seal lip and the second seal lip are inclined inward in the axial direction. A sealing device characterized in that both outer edges in the axial direction on the outer peripheral surfaces of the lip and the second seal lip are in line contact with the inner peripheral surface of the shaft hole.   The sealing device according to claim 1, further comprising a pressing member that is attached to the outer peripheral side of the cylindrical portion and presses the inner peripheral surface of the cylindrical portion toward the groove bottom of the annular groove.   The seal ring is obtained by subjecting an annular material made of PTFE to a bending process by heat press, and both end surfaces of the material are respectively outer peripheral surfaces of a first seal lip and a second seal lip. The sealing device according to claim 1, wherein:

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