Double ring oil seal

Abstract

The double-ring oil seal capable of reducing the frequency of maintenance by adjusting the supply of lubricating grease to the lip portion. A lubricating grease holding space (S2) that communicates with a sealing space (S1) through a communication hole (h) is formed by an outer sealing member (16) and an inner sealing member (22), and the lubricating grease holding space (S2) is filled with lubricating grease. Thus, since the lubricating grease is supplied from the lubricating grease holding space (S2) to the sealing space (S1) through the communication hole (h), the reduction and disappearance of the lubricating grease in the sealing space (S1) can be suppressed. Thus, the wear and the generation of abnormal noise of the side lip (20a) can be suppressed, the rustproof ability of the oil seal (10) and the shaft (14) can be improved, and the frequency of maintenance can be reduced.

Description

Technical Field

[0001] This utility model relates to a structure that improves the maintainability of oil seals. Background Technology

[0002] An oil seal is known to have an outer sealing member and an inner sealing member. The outer sealing member is disposed in the gap between a rotating body and a non-rotating body to prevent intrusion from the outside, and the inner sealing member prevents leakage from the inside. This oil seal discloses a technique in which lubricating oil (grease) is retained in a sealing space formed by the outer sealing member, the inner sealing member, and the sealing surfaces of the rotating body, maintaining the sealing performance of a sliding contact portion (hereinafter referred to as the lip) with the sealing surface of the sealing member. For example, the shaft seal for cooling media described in Patent Document 1 has such a structure.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-17161 Utility Model Content

[0006] The problem to be solved by utility models

[0007] However, in the case where the space for holding the lubricating oil (grease) is formed by the outer sealing member, the inner sealing member, and the sealing surface of the rotating body, as in Patent Document 1, when the sealing member suddenly deviates, the grease will flow out to the outside. Due to the reduction or disappearance of the grease, wear and abnormal noise may occur at the lip of the sealing member, thus increasing the frequency of maintenance to replenish the grease.

[0008] This invention was made against the background described above, and its purpose is to provide a double-ring oil seal that can reduce the frequency of maintenance by adjusting the supply of grease to the lip.

[0009] Solution for solving the problem

[0010] The purpose of this utility model is to provide a double-ring oil seal, (a) the double-ring oil seal is disposed in the gap between a non-rotating body and a rotating body to form a sealing space surrounded by an outer sealing member, an inner sealing member, and the sealing object surface of the rotating body, characterized in that (b) the outer sealing member and the inner sealing member form a grease holding space that communicates with the sealing space through a connecting hole, and (c) the grease holding space is filled with grease.

[0011] Utility Model Effect

[0012] According to this invention, the outer sealing member and the inner sealing member form a grease retention space that communicates with the sealing space through a connecting hole, and the grease retention space is filled with grease. Thus, grease is supplied from the grease retention space to the sealing space through the connecting hole, thereby suppressing the reduction or disappearance of grease in the sealing space. Therefore, a double-ring oil seal can be provided that suppresses wear and noise on the lip of the sealing member, improves the rust prevention capability of the double-ring oil seal and the rotating body, and reduces the frequency of maintenance.

[0013] Preferably, the connecting hole includes a supply regulating valve to adjust the amount of grease supplied from the grease holding space. Thus, by means of the supply regulating valve, grease is appropriately supplied to the sealing space, thereby providing a double-ring oil seal that reduces maintenance frequency.

[0014] Preferably, the grease holding space has a grease filling hole that communicates with the outer peripheral surface of the inner sealing member. This allows grease to be replenished into the grease holding space through the grease filling hole, thereby reducing maintenance frequency and improving maintainability.

[0015] Preferably, the grease filling hole is equipped with an anti-backflow valve to prevent grease from flowing out of the grease filling hole. This eliminates the need for grease fittings, caps, etc., used to block the grease filling hole.

[0016] Preferably, the seal includes both the supply regulating valve and the anti-backflow valve located at the grease replenishment orifice. This provides a double-ring oil seal that reduces maintenance frequency and improves maintainability. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view illustrating an example of an oil seal using this invention.

[0018] Figure 2 This is a cross-sectional view of an oil seal corresponding to another embodiment of the present invention.

[0019] Figure 3 This is a cross-sectional view of an oil seal corresponding to another embodiment of the present invention.

[0020] Figure 4 This is a cross-sectional view of an oil seal corresponding to another embodiment of the present invention.

[0021] Figure 5 This is a cross-sectional view of an oil seal corresponding to another embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures

[0023] 10, 10A, 40, 40A, 40B: Oil seal (double ring oil seal) 12: Housing (non-rotating body) 14: Shaft (rotating body) 14a: Outer peripheral surface (sealing surface) 14b1: Deflector bottom surface (sealing surface) 16, 46: Outer sealing component 22, 52: Inner sealing component h: Connecting hole S1: Sealing space S2: Grease retention space Detailed Implementation

[0024] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings. It should be noted that in the following embodiments, the drawings have been appropriately simplified or modified, and the dimensional ratios and shapes of the parts may not be accurately depicted.

[0025] Example 1

[0026] Figure 1 This is a cross-sectional view illustrating an example of an oil seal utilizing this invention. Figure 1 In the diagram, the right half of shaft 14, which is a rotating body, is omitted relative to its axis of rotation CL. Oil seal 10 is provided to prevent the outflow of oil filled by the sealed internal space of housing 12, which is a non-rotating body, and to prevent the intrusion of impurities from outside housing 12. Figure 1 In the diagram, the outer periphery of the shell 12 (left side of the paper) corresponds to the exterior, and the inner periphery (right side of the paper) corresponds to the interior space.

[0027] The shaft 14 passes through a through hole in the housing 12 and is supported by a bearing (not shown) so that it can rotate around the rotation axis CL. The portion of the shaft 14 that passes through the housing 12 is formed in a stepped shape, and the shaft diameter is smaller than the diameter of the inner circumferential surface 12a of the housing 12. Therefore, a gap is formed between the inner circumferential surface 12a and the outer circumferential surface 14a of the shaft 14. Furthermore, a deflector 14b for suppressing the intrusion of external impurities is provided on the lower surface of the stepped shape of the portion through which the shaft 14 passes. The deflector 14b is formed as a double cylinder having a bottom surface (hereinafter referred to as the deflector bottom surface) 14b1 perpendicular to the rotation axis CL, and its inner circumferential side is fixed to the shaft 14 by pressing or the like, and rotates integrally with the shaft 14. The oil seal 10 is formed in an annular shape and is provided in such a way as to seal the gap between the housing 12 and the shaft 14 (outer circumferential surface 14a and deflector bottom surface 14b1). It should be noted that the housing 12 is equivalent to the "non-rotating body" of this utility model, the shaft 14 is equivalent to the "rotating body" of this utility model, and the outer peripheral surface 14a and the bottom surface 14b1 of the deflector are equivalent to the "sealing object surface" of this utility model.

[0028] The oil seal 10 is a double-ring oil seal (double-ring oil seal) which includes: an outer sealing member 16 that closes the gap between the oil seal and the bottom surface 14b1 of the deflector; and an inner sealing member 22 that closes the gap between the oil seal and the outer peripheral surface 14a.

[0029] The outer sealing member 16 consists of a metal ring 18 made of metal material and formed in an L-shape cross section, and an outer seal 20 integrally formed with the metal ring 18 and made of an elastic member such as fluororubber. The outer seal 20 integrally has a side lip 20a, the front end of which can slide in close contact (sliding contact) with the bottom surface 14b1 of the deflector to prevent the intrusion of impurities from the outside.

[0030] The inner sealing member 22 consists of a metal ring 24, formed into a generally concave shape at the center of its L-shaped bottom edge, and an inner seal 26 integrally formed with the metal ring 24, made of an elastic component such as fluororubber. The inner seal 26 integrally includes a sealing lip 26a that slidably contacts the outer peripheral surface 14a of the shaft 14, and a dustproof lip 26b. The sealing lip 26a is provided to prevent oil from flowing out of the internal space of the housing 12, and a clamping spring 30 is fitted to its outer periphery. The dustproof lip 26b is provided to prevent impurities from entering the internal space of the housing 12.

[0031] like Figure 1 As shown, by providing the oil seal 10, a sealed space S1 is formed, surrounded by the outer sealing member 16, the inner sealing member 22, and the sealing surfaces of the shaft 14 (outer peripheral surface 14a and deflector bottom surface 14b1). Furthermore, a generally concave grease retention space S2 along the metal ring 24 is formed by the outer sealing member 16 and the inner sealing member 22. Moreover, the outer peripheral side (left side of the paper) of the grease retention space S2 is sealed by the cylindrical portion 28, which secures the metal ring 18 and the metal ring 24 together. That is, the outer sealing member 16 and the inner sealing member 22 are connected together by the cylindrical portion 28. Furthermore, the mating surface 22a of the concave outer peripheral side of the inner sealing member 22 is fitted into the inner peripheral surface 12a of the housing 12 by pressing or the like, thereby fixing the oil seal 10 (outer sealing member 16 and inner sealing member 22) to the housing 12.

[0032] Grease is filled into the grease holding space S2. Furthermore, on the inner circumferential side (right side of the paper) of the grease holding space S2, a connecting hole h is provided between the outer seal 20 and the inner seal 26 to connect the sealing space S1 and the grease holding space S2. Grease is supplied from the grease holding space S2 to the sealing space S1 through the connecting hole h. The shape, size, arrangement, and number of the connecting holes h are set to preferred values ​​determined through design or experimentation.

[0033] However, conventional oil seals apply grease and retain it in the sealed space S1 to suppress wear and abnormal noise of the side lip 20a. However, in the case of the sealed space S1, when the side lip 20a suddenly deviates, the grease flows out to the outside. Due to the reduction and disappearance of grease, wear and abnormal noise of the side lip 20a may occur, thus increasing the frequency of grease replenishment maintenance.

[0034] In contrast, the oil seal 10 of this embodiment has a grease holding space S2 filled with grease, and grease is supplied from the grease holding space S2 to the sealing space S1 through the connecting hole h, thereby suppressing the reduction and disappearance of grease in the sealing space S1.

[0035] As described above, according to this embodiment, a grease holding space S2 is formed by the outer sealing member 16 and the inner sealing member 22, communicating with the sealing space S1 through the connecting hole h, and the grease holding space S2 is filled with grease. Therefore, grease is supplied from the grease holding space S2 to the sealing space S1 through the connecting hole h, thus suppressing the reduction or disappearance of grease in the sealing space S1. This suppresses wear and abnormal noise of the side lip 20a, improves the rust prevention capability of the oil seal 10 and the shaft 14, and reduces the frequency of maintenance.

[0036] Next, other embodiments of the present invention will be described. It should be noted that in the following description, parts that are common to each other in the embodiments will be labeled with the same reference numerals and omitted from the description.

[0037] Example 2

[0038] Figure 2 This is a cross-sectional view of oil seal 10A corresponding to another embodiment of the present invention. Oil seal 10A is an embodiment of oil seal 10 in embodiment 1 described above, in which a supply regulating valve c is provided in the communicating hole h to regulate the amount of grease supplied from the grease holding space S2 to the sealing space S1. The supply regulating valve c is, for example, a valve mechanism that regulates the preferred amount of grease supplied based on the negative pressure of the sealing space S1, ambient temperature, etc. Regarding the regulation of the grease supply, a preferred method and setting value are predetermined through design or experimental determination.

[0039] The oil seal 10A constructed as described above also achieves the same effect as the oil seal 10 of Example 1. Furthermore, by appropriately supplying grease to the sealing space S1 through the supply quantity regulating valve c, the frequency of maintenance is reduced.

[0040] Example 3

[0041] Figure 3This is a cross-sectional view of the oil seal 40 corresponding to another embodiment of the present invention. The oil seal 40 is an example of the oil seal 10 of the aforementioned embodiment 1, in which a grease replenishment hole d is provided on the outer periphery of the grease retention space S2. For example... Figure 3 As shown, the outer periphery (left side of the paper) of the grease retention space S2 is fastened to the inner periphery (metal ring 54) by the cylindrical portion 58, but a grease filling hole d communicating with the outer periphery of the inner periphery is formed between the outer periphery (metal ring 48) and the inner periphery (metal ring 54). Moreover, similar to the oil seal 10 of Embodiment 1, the mating surface 52a of the concave outer periphery of the inner periphery is fitted to the inner periphery 12a of the housing 12 by pressing or the like, thereby fixing the oil seal 40 (outer periphery (metal ring 46) and inner periphery (metal ring 52)) to the housing 12.

[0042] Grease is supplied to the grease holding space S2 through the grease supply hole d. Furthermore, a grease fitting, a removable or disposable cap, etc., is installed in the grease supply hole d to close it. The shape, size, and arrangement of the grease supply hole d are predetermined to preferred values ​​determined through design or experimentation.

[0043] In the oil seal 40 constructed as described above, the same effect as that of the oil seal 10 in the aforementioned Example 1 can be obtained. Moreover, since grease is replenished to the grease holding space S2 through the grease replenishment hole d, maintainability can be improved.

[0044] Example 4

[0045] Figure 4 This is a cross-sectional view of oil seal 40A corresponding to another embodiment of the present invention. Oil seal 40A is an embodiment of oil seal 40 in the aforementioned embodiment 3, which includes a backflow prevention valve e in the grease filling hole d to prevent grease from flowing out of the grease filling hole d. The backflow prevention valve e is a valve mechanism that prevents grease from flowing back from the grease holding space S2 and out of the grease filling hole d, and is formed of an elastic member such as fluororubber. The shape, size, and configuration of the backflow prevention valve e are predetermined to preferred values ​​determined through design or experimentation.

[0046] The oil seal 40A constructed as described above also achieves the same effect as the oil seal 40 of Example 3. Furthermore, it eliminates the need for grease fittings, caps, etc., used to seal the grease replenishment hole d.

[0047] Example 5

[0048] Figure 5This is a cross-sectional view of oil seal 40B, corresponding to another embodiment of the present invention. Oil seal 40B is an embodiment that simultaneously applies the supply regulating valve c of embodiment 2 and the anti-backflow valve e of embodiment 4.

[0049] The same effect as in Examples 2 and 4 can be obtained in the oil seal 40B constructed as described above.

[0050] The embodiments of the present invention have been described in detail above based on the accompanying drawings, but the present invention can also be applied to other forms.

[0051] For example, in the aforementioned embodiments 1 to 5, the outer sealing members 16 and 46 are structures that close the gap between themselves and the bottom surface 14b1 of the deflector. However, they are not limited to the bottom surface 14b1 of the deflector. For example, they could also be structures that close the gap between themselves and the outer peripheral surface 14a of the shaft 14, which is located on the outer side of the inner sealing members 22 and 52. This invention can be applied as long as a double-ring oil seal forms a sealing space S1 between the sealing surfaces of the outer sealing member 16 (or 46), the inner sealing member 22 (or 52), and the shaft 14 (rotating body).

[0052] It should be noted that the above is only one implementation method, and the present invention can be implemented in various forms with modifications and improvements based on the knowledge of those skilled in the art.

Claims

1. A double-ring oil seal, wherein the double-ring oil seal is disposed in the gap between a non-rotating body and a rotating body, forming a sealing space surrounded by an outer sealing member, an inner sealing member, and the sealing surface of the rotating body, characterized in that, The outer sealing member and the inner sealing member form a grease retention space that communicates with the sealing space through a connecting hole. The grease-holding space is filled with grease.

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