JP7465632B2 - Sealing device - Google Patents

Description

The present invention relates to a sealing device.

Sealing devices such as oil seals used in shaft seals of various devices are mainly composed of an annular reinforcing ring, a rubber-like elastic body that covers the reinforcing ring, and a spring member that is attached to the rubber-like elastic body. The rubber-like elastic body has a seal lip. The seal lip mainly has, for example, a main lip that contacts the rotating shaft, and a dust lip that prevents foreign matter such as muddy water, sand, and dust from entering the sealed side.

For example, in the invention described in Patent Document 1, an air vent groove (vent portion) is provided on the outer periphery of the elastic body portion to connect the sealed side and the non-sealed side and reduce the pressure on the sealed side. The air vent groove is parallel to the axial direction and linear.

JP 2014-37224 A

In a sealing device, there is a demand for a sealing device that reduces pressure on the sealed side by communicating the sealed side with the non-sealed side via a vent groove while preventing the intrusion of foreign matter.
From this perspective, an object of the present invention is to provide a sealing device that reduces pressure on the sealed object side while preventing the intrusion of foreign matter.

In order to solve the above problem, the present invention provides a sealing device comprising an annular elastomer portion that seals a ring-shaped gap between a housing and a rotating shaft that are assembled concentrically and rotatably relative to each other, the elastomer portion having a main body portion and a seal lip portion extending from the main body portion and in sliding contact with the rotating shaft, the main body portion having an air vent groove formed on its outer periphery that connects the sealed side and the non-sealed side and reduces the pressure on the sealed side, the air vent groove having a spiral shape that winds multiple times non-parallel to the axial direction of the rotating shaft to prevent the intrusion of foreign matter .

According to the present invention, the pressure on the sealed object side can be reduced by allowing ventilation through the ventilation groove. In addition, because the ventilation groove is not parallel to the axial direction of the rotating shaft, it is difficult for foreign matter to enter the sealed object side.

The present invention provides a sealing device that reduces pressure on the sealed object while preventing the intrusion of foreign matter.

1 is a half sectional view of a sealing device according to an embodiment of the present invention in an installed state, taken along a plane passing through an axis. 1 is a perspective view of a sealing device according to a first embodiment of the present invention; FIG. 6 is a side view of a sealing device according to a second embodiment of the present invention. FIG. 11 is a perspective view of a sealing device according to a third embodiment of the present invention.

As shown in FIG. 1, the sealing device 1 according to this embodiment seals the annular gap between a housing 2 and a rotating shaft 3 that are assembled concentrically and relatively rotatably to each other. The sealing device 1 is mainly composed of a reinforcing ring 4, an elastic body portion 5, and a spring member 6.

The elastic body portion 5 has a main body portion 11, an outer periphery portion 12, a main lip 13, and a dust lip 14. The main lip 13 and the dust lip 14 form the seal lip portion. The elastic body portion 5 is a rubber-like elastic body. The main body portion 11 is a portion that covers the reinforcing ring 4. The outer periphery portion 12 is a portion that protrudes outward in the circumferential direction from the main body portion 11. The main lip 13 (primary lip 131, secondary lip 132) extends from the main body portion 11 to the sealed side A and is in sliding contact with the rotating shaft 3. The dust lip 14 extends from the main body portion 11 to the non-sealed side B and is in sliding contact with the rotating shaft 3.

The outer periphery 12 is in contact with the housing 2. The outer periphery 12 has an air vent groove 21 that connects the sealed side A and the non-sealed side B and reduces the pressure on the sealed side A. The air vent groove 21 has a labyrinth shape.

According to the sealing device 1 of this embodiment, the pressure on the sealed side A can be reduced by venting through the ventilation groove 21. In addition, because the ventilation groove 21 has a labyrinth shape (see FIG. 2) or a spiral shape (see FIG. 3), foreign matter is less likely to enter the sealed side A. This embodiment will be described in detail below.

[First embodiment]
1, the sealing device 1 is a device that seals an annular gap between a housing 2 and a rotating shaft 3 that are assembled concentrically and relatively rotatably to each other. The rotating shaft 3 is a shaft that is inserted into the housing 2. The sealing device 1 is used, for example, in an engine of industrial machinery to seal between a crankshaft and a front cover.

The sealing device 1 is mainly composed of a reinforcing ring 4, an elastic body portion 5, and a spring member 6. The reinforcing ring 4 is made of, for example, stainless steel or SPCC (cold rolled steel). The reinforcing ring 4 has a cylindrical portion 4a and a flange portion 4b that bends inward from the end of the cylindrical portion 4a on the non-sealed side B. The reinforcing ring 4 is manufactured, for example, by pressing or forging.

The elastic body 5 is mainly composed of a main body 11, an outer periphery 12, a main lip 13, and a dust lip 14. The elastic body 5 is formed, for example, from various rubber materials. Examples of rubber materials include synthetic rubbers such as nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), and fluororubber (FKM). The reinforcing ring 4 and the main body 11 form a fitting portion that is fitted to the inner periphery of the housing 2.

The elastic body portion 5 is molded by cross-linking (vulcanization) molding using a mold. During this cross-linking molding, the reinforcing ring 4 placed in the mold is cross-linked and bonded to the elastic body portion 5, so that the reinforcing ring 4 and the elastic body portion 5 are integrally formed.

The main body 11 is a portion that covers the entire reinforcing ring 4 in the circumferential direction. The outer peripheral portion 12 is a portion that protrudes outward from the outer periphery of the main body 11 and has a trapezoidal cross section. The outer peripheral portion 12 has a sealed end face 12a, a non-sealed end face 12b, and a side face 12c. The side face 12c is a portion that contacts the housing 2. The sealed end face 12a and the non-sealed end face 12b are inclined in a direction away from each other as they move from the side face 12c toward the main body 11. The sealed end face 12a and the non-sealed end face 12b may be formed perpendicular to the rotating shaft 3. The outer peripheral portion 12 has an air vent groove 21 formed therein as shown in FIG. 2. The detailed configuration of the air vent groove 21 will be described later.

The main lip 13 is a part that contacts the rotating shaft 3 and seals the fluid to be sealed. The main lip 13 extends obliquely from a root portion 13a formed on the inside of the body portion 11 toward the sealed object A side. The main lip 13 comprises a main lip 131 provided on the sealed object side A and a sub-lip 132 provided on the non-sealed object side B. The main lip 131 and the sub-lip 132 each have a triangular cross section, and their tips are in sliding contact with the rotating shaft 3. The main lip 13 may be a single lip, or may be composed of three or more lips.

The dust lip 14 is a part that contacts the rotating shaft 3 and prevents the intrusion of foreign matter such as muddy water, sand, and dust from the non-sealed side B. The dust lip 14 extends obliquely from a base portion 14a formed on the inside of the main body portion 11 toward the non-sealed side B. The tip of the dust lip 14 is in sliding contact with the rotating shaft 3. Multiple dust lips 14 may be provided.

The spring member 6 is arranged around the outside of the main lip 13 in the circumferential direction. For example, a garter spring can be used as the spring member 6. The spring member 6 applies tension to the primary lip 131 and secondary lip 132 of the main lip 13. The spring member 6 may be omitted.

As shown in FIG. 2, the ventilation groove 21 is formed continuously in the axial direction from the sealed end face 12a to the non-sealed end face 12b of the outer periphery 12. One end of the ventilation groove 21 faces the sealed end face 12a, and the other end faces the non-sealed end face 12b. The cross-sectional shape of the ventilation groove 21 is not particularly limited, but in this embodiment, it has a rectangular cross-sectional shape. In this embodiment, the ventilation groove 21 has a one-stage crank shape. That is, the ventilation groove 21 is bent at two points between the sealed end face 12a and the non-sealed end face 12b, and has one portion that is not parallel to the axial direction of the rotating shaft 3.

If the axial distance of the side surface 12c of the outer periphery 12 is "distance L1" (see FIG. 1), the ventilation groove 21 is formed so that its extension distance is at least longer than the distance L1 to prevent foreign matter such as dust from entering and to communicate the sealed side A with the non-sealed side B. In other words, the ventilation groove 21 has a passage length longer than the distance L1 by having a portion that is non-parallel to the axial direction of the rotating shaft 3. Note that the ventilation groove 21 is not limited to the form shown in FIG. 2, and may be a crank shape with two or more stages, a curved shape, a straight shape, a diagonal shape (diagonal to the rotating shaft 3), or a shape that is a combination of these, as long as it has a portion that is non-parallel to the axial direction of the rotating shaft 3. In other words, the "labyrinth shape" refers to a shape in which the ventilation groove 21 is crank-shaped, or a curved shape, a straight shape, a diagonal shape (diagonal to the rotating shaft 3), or a combination of these, and has a portion that is non-parallel to the axial direction of the rotating shaft 3.

According to the sealing device 1 of this embodiment described above, the pressure on the sealed side A can be reduced by venting through the ventilation groove 21. In addition, because the ventilation groove 21 is not parallel to the axial direction of the rotating shaft 3 (has a labyrinth shape), the path through which foreign matter can enter is longer and more complex than the distance L1. This makes it difficult for foreign matter to enter the sealed side A. In other words, the sealing device 1 can achieve both a reduction in pressure on the sealed side A and prevention of the intrusion of foreign matter.

In addition, in the manufacturing process of the elastic body portion 5, the ventilation groove 21 can be molded as a single piece using a molding die. In other words, in this embodiment, there is no need to form the ventilation groove 21 in the outer periphery 12 in a later process, which reduces the manufacturing cost of the sealing device 1.

[Second Example, Third Example]
Fig. 3 is a side view of a sealing device according to a second embodiment of the present invention. Fig. 4 is a perspective view of a sealing device according to a third embodiment of the present invention. In the second and third embodiments, the same reference numerals are used for members and the like common to the first embodiment, and detailed descriptions thereof will be omitted.

As shown in FIG. 3, in the second embodiment, the shape of the ventilation groove 21A is different from that of the first embodiment. The ventilation groove 21A is formed continuously so that it spirals around the outer periphery 12 from the sealed side end face 12a of the outer periphery 12 several times and reaches the non-sealed side end face 12b of the outer periphery 12. One end of the ventilation groove 21A faces the sealed side end face 12a, and the other end faces the non-sealed side end face 12b. In the example of FIG. 3, the entire length of the ventilation groove 21A is not parallel to the axial direction of the rotation shaft.

As shown in FIG. 4, the ventilation groove 21B of the third embodiment is formed continuously so that it runs diagonally around the outer periphery 12 from the sealed end face 12a of the outer periphery 12 and reaches the non-sealed end face 12b of the outer periphery 12. One end of the ventilation groove 21B faces the sealed end face 12a, and the other end faces the non-sealed end face 12b. The ventilation groove 21B runs around about 1/5 of the circumference of the elastic body portion 5. In the example of FIG. 4, the entire length of the ventilation groove 21B is also non-parallel to the axial direction of the rotation shaft.

According to the sealing device 1 of the second and third embodiments described above, the pressure on the sealed side A can be reduced by venting through the ventilation grooves 21A and 21B. In addition, because the ventilation grooves 21A and 21B are non-parallel (spiral shaped) to the axial direction of the rotating shaft 3, the intrusion path of foreign matter becomes longer and more complex than the distance L1. This makes it difficult for foreign matter to intrude into the sealed side A. In other words, the sealing device 1 can achieve both a reduction in pressure on the sealed side A and prevention of intrusion of foreign matter.

When the ventilation groove is formed in a spiral shape as in the second and third embodiments, it may be formed over multiple revolutions as in the second embodiment, or it may be formed so that the extension distance is at least longer than the distance L1 as in the third embodiment.

In addition, in the manufacturing process of the elastic body portion 5, the ventilation grooves 21A and 21B can be molded as a single unit using a molding die. In other words, in this embodiment, there is no need to form the ventilation grooves 21A and 21B in the outer periphery 12 in a later process, which reduces the manufacturing cost of the sealing device 1.

Although the present embodiment has been described above, it is possible to appropriately modify it. For example, in the present embodiment, one ventilation groove is provided for the sealing device 1, but multiple ventilation grooves may be provided. In addition, in the present embodiment, the outer peripheral portion 12 is provided so as to protrude outward from the main body portion 11, but the outer peripheral portion 12 may be provided over the entire height direction of the main body portion 11.
Further, in the above embodiment, the main lip 13 and the dust lip 14 are provided as the seal lip portion, but the seal lip portion may be provided with only the main lip 13 or only the dust lip 14 .

REFERENCE SIGNS LIST 1 sealing device 2 housing 3 rotating shaft 4 reinforcing ring 5 elastic body portion 6 spring member 11 main body portion 12 outer periphery 13 main lip (seal lip portion)
14 Dust lip (seal lip part)
21 Ventilation groove 21A Ventilation groove 21B Ventilation groove

Claims (1)

A sealing device having an annular elastic portion that seals an annular gap between a housing and a rotating shaft that are assembled concentrically and relatively rotatably to each other,
The elastic body portion is
A main body portion,
a seal lip portion extending from the main body portion and slidably contacting the rotating shaft;
An air vent groove is formed on the outer periphery of the main body, the air vent groove communicating the sealed side with the non-sealed side and reducing the pressure on the sealed side,
A sealing device characterized in that the ventilation groove has a spiral shape that winds multiple times non-parallel to the axial direction of the rotating shaft to prevent the intrusion of foreign matter .

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