JP7118781B2 - sealing device - Google Patents

Description

The present invention relates to a sealing device according to sealing technology. The sealing device of the present invention is used, for example, in the field of automobiles or in the field of general machinery.

For example, sealing devices (oil seals) for drive trains and undercarriages used in automobile-related fields are provided with side lips, a type of seal lip, to prevent foreign matter such as dust and muddy water from entering the machine from the outside. The side lip is slidably brought into contact with the axial end surface of a counterpart component such as a deflector on the rotation side.

However, when the side lip is brought into contact with the mating part in this way, the sliding torque increases during rotation, and there is concern that sliding heat generation and sliding wear leading to fatigue of the side lip may occur.

Therefore, conventionally, as shown in FIG. 113 is provided, and grease (not shown) for lubricating the sliding portion is filled in the groove 113. According to this configuration, the grease filled in the groove 113 exhibits a lubricating action Therefore, it is possible to suppress an increase in sliding torque and the occurrence of sliding heat generation and sliding wear (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2016-44687

However, in the prior art shown in FIG. 3, the cross-sectional shape of the groove 113 is such that the groove width w4 of the groove opening 113b is larger than the groove width _w3 of the groove bottom 113a _{( w3} < _w4 ), the entrance and exit of the grease are wide, so the grease filled in the groove 113 may flow out early. When the shaft 103 rotates at high speed, centrifugal force acts on the grease, which may accelerate the outflow of the grease.

In view of the above points, it is an object of the present invention to provide a sealing device capable of enhancing the lubricity of a sliding portion of a seal lip such as a side lip and maintaining the lubricity over a long period of time. and

In a sealing device that is mounted in a shaft hole of a housing and seals the sealing fluid inside the housing so that the sealing fluid does not leak out of the machine, the diameter of a mating part fixed to a rotating shaft passing through the shaft hole a seal lip slidably contacting an axial end face extending in the direction of the grease in a curved shape; The holding groove has an entrance portion between the edge on the tip side and the edge on the root side of the seal lip as a groove opening, and is gradually inclined from the edge on the tip side toward the tip side of the seal lip. By increasing the depth, the groove width of the groove opening is smaller than the maximum groove width in the grease holding groove .

Since the groove width at the opening of the groove is smaller than the maximum groove width in the groove, the grease inlet/outlet is narrow, which makes it difficult for the grease filled in the groove to flow out. Easy to stay in groove. Therefore, since the grease filled in the groove is gradually supplied to the sliding portion little by little, it is possible to improve the lubricity of the seal lip to the sliding portion, and furthermore, the lubricity can be maintained for a long time. It can be maintained over a period of time.

Principal part sectional drawing of the sealing device which concerns on embodiment (A), (B), and (C) are enlarged cross-sectional views of grease holding grooves provided in the same sealing device. Principal part cross-sectional view of a sealing device according to a conventional example

As shown in FIG. 1, a sealing device (oil seal) 1 according to the embodiment is mounted on the inner periphery of a shaft hole 62 of a housing 61 so as to prevent sealing fluid such as oil in the machine A from leaking to the outside B of the machine. It seals the sealed fluid and also seals external foreign matter such as dust and muddy water outside the machine B so that these foreign substances do not enter the machine interior A.

The sealing device 1 comprises a metal ring 11 having an L-shaped cross section fitted to the inner peripheral surface of the shaft hole 62 of the housing 61, and a rubber-like elastic body 21 adhered (cross-linked) to the metal ring 11, The rubber-like elastic body 21 integrally forms a main lip 31 as a first seal lip, a dust lip 41 as a second seal lip, and a side lip 51 as a third seal lip.

The main lip 31 is located closest to the machine interior A side, extends from the inner peripheral end of the metal ring 11 toward the machine interior A side, and slidably contacts the peripheral surface 64 of the shaft 63 with its inner peripheral lip end 32 . thereby sealing the sealing fluid.

A garter spring 33 is fitted around the outer circumference of the main lip 31 to adjust the contact pressure (tightening margin) of the main lip 31 against the shaft 63 . A threaded projection 35 is provided on the machine-outboard slope 34 of the inner peripheral lip end 32 to exert a pumping action on the sealing fluid when the shaft 63 rotates.

The dust lip 41 is disposed on the outboard B side of the main lip 31 and between the main lip 31 and the side lip 51, extends from the inner peripheral end of the metal ring 11 toward the outboard B side, and extends toward the outboard B side. 42 is in slidable contact with the peripheral surface 64 of the shaft 63 to provide a secondary seal against external foreign matter.

The inner peripheral surface of the dust lip 41 is provided with a protrusion 43 for adjusting the contact pressure (tightening margin) of the dust lip 41 against the shaft 63 or for forming a minute gap between the shaft 63 and the dust lip 41. there is

The side lip 51 is arranged on the outboard B side of the dust lip 41 and is closest to the outboard B side, extends from the inner peripheral end of the metal ring 11 toward the outboard B side, and is fixed to the outer circumference of the shaft 63 . External foreign matter is primarily sealed by slidably contacting an axial end surface 66 of a mating component 65 such as a deflector or a slinger.

The side lip 51 has an annular tapered portion 53 whose diameter gradually increases toward the tip portion 52 thereof. The tapered portion 53 contacts the axial end surface 66 of the mating component 65 with its inner peripheral surface 54 . Therefore, the side lip 51 is a sliding portion in which the inner peripheral surface 54 of the tapered portion 53 contacts the axial end surface 66 of the mating component 65 in a slidable manner.

Since the mating part 65 is generally made of metal and the side lip 51 is made of rubber, when the side lip 51 is in contact with the mating part 65 and the mating part 65 rotates together with the shaft 63, the sliding torque increases, and the side lip 51 may generate sliding heat and sliding wear.

As a countermeasure against this, a grease retaining groove 55 capable of retaining lubricating grease is provided on the inner peripheral surface 54 of the tapered portion 53 which is the inner peripheral surface of the side lip 51 .

The grease retaining groove 55 is formed as an annular groove, and a plurality of grooves are provided at intervals.

2A, the grease retaining groove 55 is formed in such a shape that the groove width w2 of the groove opening 55b is smaller _than the maximum groove width w1 in the groove _{( w1} > w ₂ ), especially in FIG. 2(A), the groove width of the groove bottom 55a is set to the maximum groove width w ₁ , so the grease holding groove 55 is formed in a dovetail groove shape based on a triangular cross section. , the groove width _w2 of the groove opening 55b is formed to be the narrowest.

The interior of the grease holding groove 55 is filled with grease (not shown).

In the sealing device 1 configured as described above, the mating component 65 rotates together with the shaft 63 while the side lip 51 is in contact with the axial end surface 66 of the mating component 65 . Since there is concern that sliding wear may occur, a grease holding groove 55 is provided in the inner peripheral surface 54 of the tapered portion 53, which is the inner peripheral surface of the side lip 51, and the grease is filled in the grease holding groove 55. Therefore, the grease is supplied to the sliding portion of the side lip 51 and exerts a lubricating effect.

_In addition, since the groove width w2 of the groove opening 55b of the grease holding groove 55 is smaller _than the maximum groove width w1 in the groove, the entrance and exit of the grease is narrow, and the grease is filled in the groove. It is difficult for the grease that has been applied to flow out and stays in the groove easily. Therefore, a situation is realized in which the grease filled in the groove is gradually supplied to the sliding portion little by little.

Accordingly, it is possible to improve the lubricity of the side lip 51 to the sliding portion and to maintain the lubricity of the side lip 51 to the sliding portion for a long period of time. ing.

In addition, since the grease retaining groove 55 is provided on the inner peripheral surface of the side lip 51 and on the inner peripheral surface 54 of the tapered portion 53, as a secondary effect, the reaction force of the side lip 51 is reduced, It is possible to make the lip 51 elastically deformable.

In the above-described embodiment, the grease retaining groove 55 has a dovetail shape based on a triangular cross section. It is not particularly limited.

For example, in the example of FIG. 2(B), the grease holding groove 55 is a groove having a circular cross section, and is provided with a groove opening 55b. Further, in the example of FIG. 2C, the grease holding groove 55 is a groove having a square cross section, and a groove opening 55b is provided thereon. _In either case, the groove width w2 of the groove opening 55b is smaller _than the maximum groove width w1 in the groove, and the entrance and exit of the grease are narrow. can be gradually supplied to the sliding portion in small amounts.

Reference Signs List 1 sealing device 11 metal ring 21 rubber-like elastic body 31 main lip 32 inner peripheral lip end 33 garter spring 34 outer slope 35 screw projection 41 dust lip 42, 52 tip portion 43 projection 51 side lip (seal lip)
53 Taper portion 54 Inner peripheral surface 55 Grease holding groove 55a Groove bottom 55b Groove opening 61 Housing 62 Shaft hole 63 Shaft 64 Peripheral surface 65 Mating part 66 Axial end face w ₁ Maximum groove width w ₂ Groove width of groove opening A Inside machine B Outside

Claims (7)

A sealing device mounted in an axial hole of a housing for sealing the sealing fluid in the housing so that the sealing fluid does not leak out of the machine,
a seal lip slidably contacting a radially extending axial end face of a mating component fixed to a rotating shaft passing through the shaft hole in a curved shape ;
a grease retaining groove annularly provided in the sliding surface of the seal lip contacting the axial end surface ;
with
The grease retaining groove is
An inlet portion between the edge on the tip side and the edge on the root side of the seal lip is defined as a groove opening,
The groove width of the groove opening is smaller than the maximum groove width in the grease holding groove by increasing the depth so as to gradually incline from the edge of the tip side toward the tip side of the seal lip. A sealing device, characterized in that it is formed in The sealing device according to claim 1,
A sealing device according to claim 1, wherein the grease retaining groove has a triangular cross-section when taken along a plane including the axial center of the shaft. The sealing device according to claim 1,
A sealing device according to claim 1, wherein the grease retaining groove has a circular cross section when taken along a plane including the axis of the shaft . In the sealing device according to any one of claims 1 to 3 ,
a main lip slidably contacting the peripheral surface of the shaft and sealing the sealing fluid;
A sealing device according to claim 1, wherein said seal lip is a side lip arranged outside said main lip . The sealing device according to claim 4,
The side lip has an annular tapered portion whose diameter dimension gradually increases toward the distal end side, and when combined with the mating component, the tapered portion curves radially outward so that the A sealing device, wherein the sliding surface provided on the inner peripheral surface of the tapered portion is in contact with the axial end surface of the mating part. 6. The grease retaining groove according to any one of claims 1 to 5, wherein the depth of the grease retaining groove increases so as to gradually incline from the edge on the root side toward the root side of the seal lip. sealing device. The differential side seal according to any one of claims 1 to 6, wherein a plurality of said grease retaining grooves are provided.

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