JP2016061408A - Sealing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing device which suppresses the deformation of a lip part caused by a centrifugal force, and whose sealing function is suitably maintained, in the sealing device which seals an annular clearance between a shaft and a housing, and rotates together with the housing.SOLUTION: A sealing device comprises a reinforcing ring 110 having an inward flange part 112 which extends to the inside of a radial direction, and a rubber elastic-body made seal main body 120 which is arranged at the reinforcing ring 110 integrally therewith. The seal main body 120 comprises a lip part 121 which extends to a sealing region side (O) from the inside of the radial direction rather than a tip 113 of the inward flange part 112 at an internal peripheral side, and slidably contacts with an external peripheral face of a shaft 200, and a weight part 122 which is a portion extending to an atmosphere side (A) from the inside of the radial direction rather than the tip 113, does not contact with the external peripheral face of the shaft 200, and is formed so as to make a force inward of the radial direction act on the lip part 121 when deformed outwardly in the radial direction by a centrifugal force which acts during rotation.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sealing device that seals an annular gap between a shaft and a housing, the sealing device rotating with the housing.

  Conventionally, in order to seal an annular gap between a shaft and a housing, a sealing device such as an oil seal provided with a lip portion (seal lip) in contact with the outer peripheral surface of the shaft is known. In the configuration in which the housing rotates, when the sealing device is fixed to the housing, the sealing device rotates together with the housing (see Patent Document 1). Therefore, conventionally, the lip portion is deformed so as to expand radially outward with the vicinity of the root as a fulcrum due to the centrifugal force acting when the housing rotates, and the sealing function may be impaired.

Japanese Utility Model Publication No. 5-79130

  An object of the present invention is to provide a sealing device that seals an annular gap between a shaft and a housing, and that rotates together with the housing, so that the deformation of the lip due to centrifugal force is suppressed, and thus the sealing function is suitably maintained. To provide an apparatus.

The present invention employs the following means in order to solve the above problems.
That is, the sealing device of the present invention is
A sealing device rotating with the housing for sealing an annular gap between the shaft and the housing,
A reinforcing ring comprising a cylindrical portion and an inward flange portion extending radially inward from the cylindrical portion;
A seal body made of a rubber-like elastic body provided integrally with the reinforcing ring;
A sealing device comprising:
The seal body is
A lip portion that slidably contacts the outer peripheral surface of the shaft, extending from the radially inner side to the sealed region side from the inner peripheral side tip of the inward flange portion;
The portion extending from the radially inner side to the opposite side of the sealing region from the inner peripheral side tip of the inward flange portion, and is not in contact with the outer peripheral surface of the shaft, and by centrifugal force acting during rotation A weight portion formed so as to apply a radially inward force to the lip portion when deformed radially outward.

According to the sealing device of the present invention, the seal body includes the weight portion that extends in the direction opposite to the direction in which the lip portion extends, in addition to the lip portion that slidably contacts the outer peripheral surface of the shaft. The weight portion is formed so as to apply a radially inward force to the lip portion when deformed radially outward by a centrifugal force acting during rotation. Specifically, when the weight portion is deformed radially outward by centrifugal force, the inner peripheral side of the weight portion is pulled. Therefore, the weight part is formed so that the inner peripheral side of the lip part can be pulled when the inner peripheral side is pulled. Therefore, according to the present invention, when the sealing device is rotating together with the housing, the weight portion is deformed radially outward, thereby preventing the lip portion from being deformed so as to expand radially outward. . As a result, the contact state of the lip portion with respect to the shaft can be maintained, so that the sealing function of the sealing device can be preferably maintained. The weight portion is formed so as not to contact the outer peripheral surface of the shaft. In this case, the distance from the central axis of rotation of the sealing device to the weight portion is larger than when the weight portion having the same shape and weight is formed so as to contact the outer peripheral surface of the shaft. A larger centrifugal force acts on the weight part. Therefore, according to the present invention, since the deformation of the weight portion is promoted, the sealing function of the sealing device can be more suitably maintained.

  Moreover, according to this invention, you may make it the said weight part have a mass larger than the mass of the said lip | rip part. According to this configuration, since a relatively large centrifugal force acts on the weight portion, the weight portion can be largely deformed radially outward. As a result, it becomes possible to apply a greater force to the lip portion inward in the radial direction, and thus it is possible to further suppress the deformation of the lip portion and thereby more favorably maintain the sealing function of the sealing device. It becomes possible.

  Further, according to the present invention, the weight portion is formed such that the center of gravity of a cross section by a plane including the central axis of the sealing device is located radially outside the center of gravity of the cross section of the lip portion by the plane. May be. According to this configuration, since the centrifugal force larger than the centrifugal force acting on the lip portion acts on the weight portion, the weight portion can be further deformed radially outward. As a result, it is possible to further suppress the deformation of the lip portion and thereby more favorably maintain the sealing function of the sealing device.

  Moreover, according to this invention, the said weight part may be formed so that it may extend further radially inward from the radial inner side rather than the front-end | tip of the inner peripheral side of the said inward flange part. According to this configuration, when the inner peripheral side of the weight part is pulled due to the weight part deforming radially outward, the inner peripheral side of the lip part is more effectively pulled. Therefore, when the weight portion is deformed outward in the radial direction by the centrifugal force, it is possible to more reliably apply the radially inward force to the lip portion.

  According to the present invention, in the sealing device that seals the annular gap between the shaft and the housing and rotates together with the housing, it becomes possible to suppress the deformation of the lip portion due to the centrifugal force, so that the sealing function is preferably maintained. It becomes possible to do.

It is typical sectional drawing of the sealing device which concerns on the Example of this invention. It is typical sectional drawing which shows the state at the time of rotation 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. .

(Example)
With reference to FIG.1 and FIG.2, the sealing device based on the Example of this invention is demonstrated. In the present embodiment, an oil seal that suppresses oil leakage in the sealed region will be described as an example of a sealing device. FIG. 1 is a schematic cross-sectional view of an oil seal according to an embodiment of the present invention, and is a cross-sectional view taken along a plane including the central axis of the oil seal. For the purpose of explanation of dimensions and the like, the seal main body of the oil seal has a shape when no external force is applied, and the axis is indicated by a broken line. The depth is omitted as appropriate. FIG. 2 is a schematic cross-sectional view showing a state when the oil seal according to the embodiment of the present invention is rotating together with the housing. FIG. 2 is a cross-sectional view taken along a plane including the central axis of the oil seal, as in FIG. Since the upper side and the lower side of the central axis are axisymmetric, the lower side of the central axis is omitted. The depth is omitted as appropriate.

<Configuration of oil seal>
With reference mainly to FIG. 1, the structure of the oil seal 100 which concerns on a present Example is demonstrated. The oil seal 100 according to the present embodiment seals the annular gap between the shaft 200 and the housing 300, and rotates together with the housing 300. The oil seal 100 includes a metal reinforcing ring 110 and a seal body 120 made of a rubber-like elastic body provided integrally with the reinforcing ring 110. The oil seal 100 is formed by, for example, insert molding. When the oil seal 100 is in use, the right side in the figure is the sealed area side (O) where the fluid to be sealed is sealed, and the left side in the figure is the atmosphere side (A) opposite to the sealed area. In this embodiment, the fluid to be sealed is oil.

  The reinforcing ring 110 includes a cylindrical portion 111 that is parallel to the central axis C of the oil seal 100 and an inward flange portion 112 that extends radially inward from the atmosphere side (A) end of the cylindrical portion 111. The oil seal 100 is fixed to the housing 300 by fitting the outer peripheral surface of the cylindrical portion 111 to the inner peripheral surface of the housing 300. In the present embodiment, the radially inner side of the inward flange portion 112 is slightly curved toward the sealed region side (O). The reinforcing ring 110 may be made of a material other than metal as long as it is a rigid body. Further, a portion made of a rubber-like elastic body is further provided on the outer diameter side of the cylindrical portion 111, and when the portion made of the rubber-like elastic body is fitted to the inner peripheral surface of the housing 300, the oil seal 100 is It may be fixed.

  The seal body 120 is similar to the lip portion 121 that slidably contacts the outer peripheral surface of the shaft 200 and extends from the radially inner side to the sealing region side (O) with respect to the inner peripheral side tip 113 of the inward flange portion 112. A weight portion 122 extending from the radially inner side to the sealing region side (O) (that is, the atmosphere side (A)) from the tip end 113 is provided. In this embodiment, the seal main body 120 includes a connection portion 123 that connects the lip portion 121 and the weight portion 122 on the radially inner side of the tip 113. Here, “inward in the radial direction from the tip 113” means a region (space) in which the distance from the central axis C is smaller than the distance from the central axis C to the tip 113. That is, in the cross section shown in FIG. 1, the region between the broken lines L <b> 1 and L <b> 2 is a region “inward in the radial direction from the tip 113”. Further, the “tip” here is not limited to the edge like the tip 113 shown in FIG. 1, but may be an end on the inner peripheral side of the inward flange portion 112 (that is, the most radially inner portion). It may be a surface. The lip portion 121 “extends from the radially inner side to the sealing region side (O) with respect to the tip 113” means that at least a part of the lip portion 121 (that is, a part on the inner peripheral side) is more than the tip 113. It means that it extends from “inside in the radial direction”. The same applies to the weight part 122.

  In the present embodiment, the weight portion 122 does not contact the outer peripheral surface of the shaft 200, and the radial direction with respect to the lip portion 121 is deformed outward in the radial direction by the centrifugal force acting during rotation. It is formed to apply an inward force. In other words, the weight portion 122 extends further radially inward from the radially inner side than the tip 113 of the inward flange portion 112. Therefore, as shown in FIG. 1, the seal main body 120 has a constricted (depressed) shape at the connection portion 123 when viewed in a cross section by a plane including the central axis C. Accordingly, when the weight portion 122 is deformed so as to expand outward in the radial direction due to the centrifugal force during rotation, the inner peripheral side of the weight portion 122 is pulled, whereby the lip portion 121 is connected via the inner peripheral side of the connection portion 123. The inner peripheral side of the is pulled. As a result, when the weight portion 122 is deformed radially outward by centrifugal force, a radially inward force acts on the lip portion 121.

  In the present embodiment, the weight portion 122 is configured to have a mass larger than the mass of the lip portion 121. Here, the seal body 120 is a member made of a single elastic material, and its density is substantially equal throughout. Therefore, in this embodiment, as shown in FIG. 1, the area of the cross section S <b> 2 of the weight part 122 is larger than the area of the cross section S <b> 1 of the lip part 121 when viewed in a cross section by a plane including the central axis C. It is formed to be large. Further, in the present embodiment, the weight portion 122 is formed such that the center of gravity M2 of the cross section by the plane including the central axis C is positioned radially outside the center of gravity M1 of the cross section of the lip portion 121 by the plane. Yes.

<Use condition of oil seal>
The use state of the oil seal 100 according to the present embodiment will be described mainly with reference to FIG. As already described, the oil seal 100 according to the present embodiment is fixed to the housing 300, and the tip of the lip 121 of the seal body 120 is slidably in contact with the outer peripheral surface of the shaft 200. The annular gap between the shaft 200 and the housing 300 is sealed. The lip portion 121 has an inner diameter D1 at its tip that is smaller than the outer diameter D2 of the shaft 200. Therefore, when the shaft 200 is inserted into the shaft hole of the oil seal 100, the tip of the lip portion 121 contacts the outer peripheral surface of the shaft 200 in a state of being expanded radially outward. Thereby, the tip of the lip 121 is pressed against the outer peripheral surface of the shaft 200 by the restoring force of the lip 121 acting inward in the radial direction, so that the sealing function by the lip 121 is exhibited.

  When the housing 300 rotates, the oil seal 100 rotates with the housing 300. Here, since the connection portion 123 of the seal body 120 is provided on the radially inner side of the inward flange portion 112 made of a rigid body, the connection portion 123 does not substantially deform even when a centrifugal force is applied during rotation. On the other hand, since the lip portion 121 extends from the connection portion 123 to the sealing region side (O), the centrifugal force acting during rotation is deformed radially outward with the root of the lip portion 121 as a fulcrum. It works to let you. However, the seal body 120 is provided with a weight portion 122 extending from the connection portion 123 to the atmosphere side (A). The weight part 122 is deformed outward in the radial direction with the root as a fulcrum by centrifugal force acting during rotation. That is, the shape shown by the broken line in FIG. 2 changes from the shape when no external force is applied to the shape shown by the solid line when deformed outward in the radial direction. Here, the weight portion 122 is formed so as not to contact the outer peripheral surface of the shaft 200, and the seal body 120 is constricted at the connection portion 123 when viewed in a cross section by a plane including the central axis C. It has a shape. Therefore, when the weight portion 122 is deformed so as to expand outward in the radial direction due to the centrifugal force during rotation, the inner peripheral side of the weight portion 122 is pulled, and thus the lip portion 121 of the lip portion 121 is connected via the inner peripheral side of the connection portion 123. The inner peripheral side is pulled. That is, when the weight portion 122 is deformed radially outward by the centrifugal force, the radially inward force F acts on the lip portion 121. Accordingly, the lip portion 121 is prevented from being deformed so as to expand outward in the radial direction due to centrifugal force, so that the contact state of the lip portion 121 with respect to the shaft 200 can be maintained.

<Excellent point of oil seal according to this embodiment>
According to the oil seal 100 according to the present embodiment, when the oil seal 100 rotates, the weight 122 is deformed by centrifugal force, so that the state where the tip of the lip 121 is in contact with the outer peripheral surface of the shaft 200 is maintained. . Therefore, according to the oil seal 100, even when the oil seal 100 rotates with the housing 300, the sealing function can be suitably maintained.

Further, according to the oil seal 100, the weight portion 122 is formed so as not to contact the outer peripheral surface of the shaft 200. Therefore, the distance from the central axis C to the weight part 122 is larger than when the weight part having the same shape and weight is formed so as to come into contact with the outer peripheral surface of the shaft 200. It acts on the weight part 122. Therefore, the oil seal 100
Since the deformation of the weight portion 122 is promoted, the sealing function of the oil seal 100 can be suitably maintained. Moreover, since the weight part 122 does not contact the outer peripheral surface of the axis | shaft 200, the design freedom of the shape of the weight part 122 becomes high.

  Further, according to the oil seal 100, the weight portion 122 has a mass larger than the mass of the lip portion 121. The weight part 122 is formed such that the center of gravity M2 of the cross section by the plane including the central axis C is located radially outside the center of gravity M1 of the cross section of the lip part 121 by the plane. The magnitude of the centrifugal force acting on a rotating object is expressed as "the product of the mass of the object, the distance from the center of rotation, and the square of the angular velocity of rotation". Accordingly, a centrifugal force larger than the centrifugal force acting on the lip portion 121 acts on the weight portion 122. As a result, since the weight portion 122 is greatly deformed outward in the radial direction, the deformation of the lip portion 121 can be more effectively suppressed, and thus the sealing function of the oil seal 100 can be more suitably maintained. .

(Modification)
Although the preferred embodiments of the present invention have been described above, the present invention includes various other modifications. In particular, regarding the configuration of the seal body, other configurations that can be conceived by those skilled in the art are also included in the present invention. That is, in this embodiment, the seal body 120 includes the connection portion 123 in addition to the lip portion 121 and the weight portion 122 on the radially inner side of the tip 113 of the inward flange portion 112. The shape of the seal body included in the sealing device is not limited to this. For example, the lip portion and the weight portion may be branched on the radially inner side from the tip of the inward flange portion without providing the connection portion. That is, the lip portion and the weight portion may be configured to be V-shaped when viewed in a cross section by a plane including the central axis of the sealing device. Alternatively, the weight portion may be formed so as to extend from the radially inner side to the atmosphere side and the radially outer side from the tip on the inner peripheral side of the inward flange portion. It should be noted that, regardless of the shape of the seal body, which part of the seal body corresponds to the lip portion or the weight portion can be determined from the shape or deformation mode of those portions. For example, the lip portion extends from the radially inner side to the sealing region side from the inner peripheral side tip of the flange portion, and is a portion that slidably contacts the outer peripheral surface of the shaft (including the contacting portion), If the weight portion is not provided, it can be a portion that is deformed so as to expand outward in the radial direction with its root as a fulcrum by centrifugal force acting during rotation. Also, the weight part is a part that extends from the radially inner side to the atmosphere side than the tip on the inner peripheral side of the flange part and does not contact the outer peripheral surface of the shaft, and its root is a fulcrum by centrifugal force acting during rotation. It can be set as the part which deform | transforms so that it may expand radially outward. When considering the mass of the weight part and the lip part and the position of the cross section, the weight part and the lip part may be specified as described above.

DESCRIPTION OF SYMBOLS 100 Oil seal 110 Reinforcement ring 112 Inward flange part 120 Seal body 121 Lip part 122 Weight part 200 Axis 300 Housing C Central axis

Claims (4)

A sealing device rotating with the housing for sealing an annular gap between the shaft and the housing,
A reinforcing ring comprising a cylindrical portion and an inward flange portion extending radially inward from the cylindrical portion;
A seal body made of a rubber-like elastic body provided integrally with the reinforcing ring;
A sealing device comprising:
The seal body is
A lip portion that slidably contacts the outer peripheral surface of the shaft, extending from the radially inner side to the sealed region side from the inner peripheral side tip of the inward flange portion;
The portion extending from the radially inner side to the opposite side of the sealing region from the inner peripheral side tip of the inward flange portion, and is not in contact with the outer peripheral surface of the shaft, and by centrifugal force acting during rotation A weight portion formed to apply a radially inward force to the lip portion when deformed radially outward;
A sealing device comprising:   The sealing device according to claim 1, wherein the weight portion has a mass larger than a mass of the lip portion.   The weight part is formed so that the center of gravity of a cross section by a plane including the central axis of the sealing device is located radially outside the center of gravity of the cross section of the lip part by the plane. Sealing device.   The sealing device according to any one of claims 1 to 3, wherein the weight portion is formed so as to extend further radially inward from a radially inner side than a tip on an inner peripheral side of the inward flange portion. .

Images