JP6106888B2 - Oil seal - Google Patents

Description

  The present invention relates to an oil seal, and more particularly, to an oil seal suitable for preventing a seal lip from being inverted due to insertion of a rotating shaft when the oil seal is assembled.

  Conventionally, an oil seal is known as one type of sealing device that prevents leakage of a sealing fluid to be sealed, such as lubricating oil or hydraulic oil (see, for example, Patent Document 1).

  Such an oil seal includes a seal lip formed of a rubber-like elastic body whose lip tip is slidably in contact with a rotating shaft.

  By the way, in the conventional oil seal, when the rotary shaft is inserted from the sealing side with respect to the oil seal, the seal lip may be buckled and reversed (lip reversal) so as to be drawn to the atmosphere side by the rotary shaft. There was a problem.

  Therefore, in order to cope with such problems, a configuration in which a backup ring for supporting a seal lip as described in Patent Document 2 is provided, or lip inversion as described in Patent Document 3 is prevented. The structure which attaches a protector to a reinforcement ring so that it may be located in the sealing side of a seal lip is proposed.

JP 2003-090441 A JP 2007-231967 A Japanese Utility Model Publication No. 05-019740

  However, in the configuration that prevents the lip reversal by providing the conventional backup ring, since the restriction of the displacement when the seal lip is elastically deformed by the backup ring is reduced, the follow-up of the seal lip with respect to the rotating shaft is hindered, There was a problem that the eccentricity of the shaft was insufficient, a stable sealing performance could not be obtained, the number of parts increased, and it took time and effort to incorporate a backup ring, resulting in an increase in cost.

  Further, in the configuration in which the protector is provided, there are problems that the number of parts is increased and that it takes time to incorporate a backup ring, resulting in an increase in cost.

  Therefore, there is a demand for an oil seal that can prevent lip reversal with a simple structure.

  The present invention has been made in view of these points, and an object of the present invention is to provide an oil seal that can prevent lip reversal with a simple structure.

In order to solve the above-mentioned problems, an oil seal according to the present invention is an oil seal having a seal lip whose lip end is slidably in contact with a rotating shaft. Of the inner surface located on the atmosphere side, the seal lip extends in the axial direction to a non-contact area formed on the atmosphere side from a contact area that contacts the rotating shaft, and the atmosphere side end is the waist of the seal lip. A plurality of reinforcing projections that are not in contact with the rotating shaft disposed inside the base when elastically deforming are integrally formed at intervals along the circumferential direction, and at least one end in the axial direction of the reinforcing projections Is formed with a wide portion whose width increases toward the outside in the axial direction, and the surface of the reinforcing convex portion seals the sealing fluid existing in the reinforcing convex portion forming region when the rotary shaft rotates. Guide to the side It is characterized in that a plurality of auxiliary thread groove is formed.

And by adopting such a configuration, the reinforcing convex part can reinforce the strength against the external force applied to the waist part from the axial direction, so that it does not hinder the followability of the seal lip with respect to the rotating shaft. Lip inversion when the shaft is inserted from the sealed side can be prevented. As a result, it is possible to prevent lip reversal when the rotating shaft is inserted from the sealed side with a simple structure. Furthermore, since the wide part and the auxiliary screw groove can guide the sealing fluid existing on the inner surface of the waist part toward the sealing side when the rotating shaft rotates, the sealing performance when the rotating shaft rotates can be further improved. it can.

  Further, in the present invention, the seal surface of the seal lip is formed with a plurality of screws that exhibit a pumping action that pushes back a sealing fluid that attempts to leak from the sealing side to the atmosphere side when the rotary shaft rotates, to the sealing side, An end portion on the sealing side of the reinforcing convex portion may be arranged on the atmosphere side from the atmosphere side ends of the plurality of screws. As a result, the plurality of screws can exert a pumping action that pushes back the sealing fluid that tries to leak from the sealing side to the atmosphere side when the rotating shaft rotates, so that the sealing performance when the rotating shaft rotates is improved. Can be increased.

  According to the oil seal of the present invention, the reinforcing convex portion can reinforce the strength against the external force applied to the waist portion from the axial direction, so that the rotating shaft is sealed without hindering the followability of the seal lip with respect to the rotating shaft. Lip inversion when inserted from the side can be prevented. As a result, there are excellent effects such as prevention of lip reversal when the rotating shaft is inserted from the sealing side with a simple structure.

Sectional drawing which shows the principal part of 1st Embodiment of the oil seal which concerns on this invention. It is a schematic diagram which shows the modification of the reinforcement convex part of FIG. 1, (a) is wavy, (b) is a continuous mountain shape. Sectional drawing which shows the principal part of 2nd Embodiment of the oil seal which concerns on this invention. Sectional drawing which shows the principal part of 3rd Embodiment of the oil seal which concerns on this invention. Sectional drawing which shows the principal part of 4th Embodiment of the oil seal which concerns on this invention. Sectional drawing which shows the principal part of 5th Embodiment of the oil seal which concerns on this invention.

  The present invention will be described below with reference to embodiments shown in the drawings.

(First embodiment)
FIG. 1 shows a first embodiment of an oil seal according to the present invention.

  As shown in FIG. 1, the oil seal 10 of the present embodiment is formed by integrally baking a seal body 30 formed of a rubber-like elastic body such as rubber on a reinforcing ring 20 formed of metal or resin. Has been.

  The reinforcing ring 20 has a cylindrical portion 21 and an inward flange portion 22 formed to extend from the end of the atmospheric side AS shown on the left side of the cylindrical portion 21 in FIG. As a whole, a sealing-side OS on which a sealing fluid such as lubricating oil or hydraulic oil shown on the right side in FIG. 1 is present is formed in an annular shape having an L-shaped cross section in the horizontal direction.

  The seal body 30 includes an annular outer peripheral seal portion 31 for attaching the oil seal 10 to the housing H, an annular seal lip 32 for embedding and sealing the rotating shaft S, and an annular shape for preventing foreign matter from entering. And a dust lip 33 of dust.

  The outer peripheral seal portion 31 is formed in an annular shape so as to cover the outer periphery of the cylindrical portion 21 of the reinforcing ring 20, and is fitted to the inner surface of the housing H with an appropriate margin.

  The seal lip 32 is formed to rise gradually from the inner peripheral portion of the reinforcing ring 20 toward the sealing side OS where a sealing fluid such as lubricating oil is present. The position of the small diameter of the seal lip 32 is a lip tip 35a. The lip tip 35a is formed so as to come into contact with the rotating shaft S with an appropriate tightening margin, and is slidably in close contact with the rotating shaft S. Further, on the inner surface of the seal lip 32, a seal surface 35 (lip rear surface) formed with a large diameter from the lip tip 35a toward the inner periphery of the reinforcing ring 20, and a large diameter from the lip tip 35a toward the sealing side OS. The finishing surface 36 (lip front surface) formed in the above is formed. That is, the small diameter position of the seal surface 35 is the lip tip 35a. Further, the sealing side OS adjacent to the lip tip 35a of the seal surface 35 is a contact area 37 that contacts the rotating shaft S, and the atmosphere side AS from the contact area 37 does not contact the rotating shaft S. 38.

  In the non-contact region 38, a plurality of reinforcing projections 40 that are not in contact with the rotating shaft S extending in the axial direction are integrally formed at intervals along the circumferential direction. The atmospheric side end portions of these reinforcing projections 40 are arranged inside the base portion 39a when the waist portion 39 of the seal lip 32 is elastically deformed, and the sealing side end portion is in contact with the contact region 37 of the non-contact region 38. It is arrange | positioned from the boundary part of the atmosphere side AS. Moreover, the reinforcement convex part 40 in this embodiment is formed in the rectangular shape long in an axial direction when it sees toward a radial direction outer side from an axial center. The reinforcing projections 40 may be formed with a uniform height (thickness), a low sealing side OS, a high atmospheric side AS, or a circumferential center. A part may be high and both sides or one side may be formed low.

  In addition, as a cross-sectional shape of the reinforcement convex part 40, it can select from various shapes, such as a rectangle, a semicircle, a semi-ellipse, a trapezoid, a mountain shape, and a triangle.

  Moreover, as a cross-sectional shape of the sealing surface 35 including the reinforcing convex portion 40, a shape in which unevenness is repeated along the circumferential direction, for example, a wave shape shown in FIG. 2A and a mountain shape shown in FIG. It may be a mountain shape. 2 schematically shows a state in which the non-contact region 38 including the reinforcing convex portion 40 of the seal surface 35 is cut in a direction orthogonal to the axial direction.

  Of course, it is important that the reinforcing convex portion 40 has a height and shape that does not contact the rotation axis S.

  A garter spring 45 for holding a radial compressive force between the seal lip 32 and the rotary shaft S is disposed on the back surface of the seal lip 32 on the radially outer side of the lip tip 35a.

  The oil seal 10 can be configured without the dust lip 33 or without the garter spring 45.

  Next, the operation of the present embodiment having the above-described configuration will be described.

  The reinforcing convex portion 40 of the oil seal 10 according to the present embodiment can reinforce the strength against the external force applied to the waist portion 39 from the axial direction. Lip inversion when the shaft S is inserted from the sealing side OS can be prevented. As a result, it is possible to prevent lip reversal when the rotating shaft S is inserted from the sealing side OS with a simple structure.

(Second Embodiment)
FIG. 3 shows a second embodiment of the oil seal according to the present invention. The oil seal of this embodiment is provided with a wide portion at least at one end in the axial direction (longitudinal direction) of the reinforcing convex portion of the oil seal of the first embodiment described above.

  That is, the reinforcing convex portion 52 of the oil seal 50 according to the present embodiment is formed with a wide portion 54 whose width increases toward the outer side in the axial direction on both the sealing side end portion and the atmospheric side end portion that are on the outer side in the axial direction. (In FIG. 3, only the wide part 54 of one reinforcing convex part 52 is provided with a reference numeral). The shape of the wide portion 54 can be selected from various shapes such as a semicircle, a semi-ellipse, and a triangle. Moreover, the wide part 54 is good also as a structure provided only in the air | atmosphere side edge part of the reinforcement convex part 52, or providing only in a sealing | sticker side edge part. Furthermore, as the shape of the wide part 54, it is good also as a shape which connects the edge part of the axial direction outer side of two adjacent wide parts 54. FIG.

  A plurality of auxiliary thread grooves 56 (straight lines in FIG. 3) are provided on the surface of the reinforcing convex portion 52 to guide the sealing fluid existing in the formation region of the reinforcing convex portion 52 to the sealing side OS when the rotation shaft S rotates. Simplified) is formed.

  According to the oil seal 50 of the present embodiment having such a configuration, the same effect as that of the oil seal 10 of the first embodiment described above can be obtained, and the wide portion 54 and the auxiliary screw groove 56 can rotate the rotation shaft S. Sometimes, the sealing fluid present in the formation region of the auxiliary convex portion 52 can be guided toward the sealing side OS, so that the sealing performance when the rotating shaft S rotates can be improved.

(Third embodiment)
FIG. 4 shows a third embodiment of the oil seal according to the present invention. The oil seal of the present embodiment has a plurality of pumping actions that push back the sealing fluid that attempts to leak from the sealing side to the atmosphere side when the rotating shaft rotates, on the sealing surface of the oil seal of the first embodiment described above. These screws are provided.

  That is, the seal surface 35 of the oil seal 60 of the present embodiment has a lip tip 35a that exerts a pumping action that pushes back the sealing fluid that attempts to leak from the sealing side OS to the atmosphere side AS when the rotating shaft S rotates. A plurality of screws 62 are formed for connection to. The shape of these screws 62 can be selected from conventionally known various shapes. Further, the atmosphere side end portions of the plurality of screws 62 are disposed on the sealing side OS of the non-contact region beyond the atmosphere side end portion of the contact region 37, and the atmosphere side AS is more than the atmosphere side end portions of the plurality of screws 62. A reinforcing convex portion 64 similar to the reinforcing convex portion 40 in the oil seal 10 of the first embodiment described above is formed. That is, the sealing-side end portions of the reinforcing convex portions 64 are arranged from the air-side ends of the plurality of screws 62 to the air-side AS. The reinforcing convex portion 64 may be provided with the wide portion 54 and the auxiliary screw groove 56 described above (see the oil seal 50 of the second embodiment: FIG. 3).

  Since other configurations are the same as those of the oil seal 10 of the first embodiment described above, the same reference numerals are given to the main parts in the drawings, and detailed descriptions thereof are omitted.

  According to the oil seal 60 of the present embodiment having such a configuration, the same effects as those of the oil seals 10 and 50 of the first and second embodiments described above can be obtained, and the plurality of screws 62 can be connected to the rotary shaft S. Since the pumping action that pushes back the sealing fluid that leaks from the sealing side OS to the atmosphere side AS to the sealing side OS during rotation can be exerted, the sealing performance when the rotating shaft S rotates can be improved.

(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the oil seal according to the present invention. The oil seal of the present embodiment has an annular recess having a larger diameter than the large diameter portion of the seal surface on the atmosphere side of the seal surface by shortening the axial length of the seal surface of the oil seal of the first embodiment described above. Is provided.

  That is, the seal surface 72 of the oil seal 70 of the present embodiment is disposed at a position where the end of the atmosphere side end of the seal surface 72 slightly exceeds the contact region 37 to the atmosphere side. In the AS, an annular recess 74 having a larger diameter than the large diameter portion of the seal surface 72 is formed. The annular recess 74 has a tapered inclined surface 74 a that has a gentle slope from the angle formed by the seal surface 72 and the rotation axis S, and the atmospheric-side end of the annular recess 74 faces the dust strip 33. It extends. And the reinforcement convex part 75 similar to the reinforcement convex part 40 in the oil seal 10 of 1st Embodiment mentioned above is formed in the inside of the annular recessed part 74. As shown in FIG. The reinforcing convex portion 75 may be provided with the wide portion 54 and the auxiliary screw groove 56 described above (see the oil seal 50 of the second embodiment: FIG. 3). The small diameter position of the seal surface 72 is a lip tip 72a.

  Since other configurations are the same as those of the oil seal 10 of the first embodiment described above, the same reference numerals are given to the main parts in the drawings, and detailed descriptions thereof are omitted.

  According to the oil seal 70 of the present embodiment having such a configuration, the same effect as that of the oil seal 10 of the first embodiment described above can be obtained, and the inner surface of the seal lip 32 positioned on the atmosphere side AS from the lip tip 72a. Since the thickness of the portion of the non-contact region 38 located on the atmosphere side AS can be reduced, the followability of the seal lip 32 with respect to the rotation axis S can be improved.

  In addition, when it is set as the structure which provides the wide part 54 and the auxiliary | assistant thread groove 56 with respect to the oil seal 70 of 4th Embodiment, in addition to said effect, the oil seal 70 of this embodiment is the 1st mentioned above. The same effects as the oil seal 50 of the second embodiment are obtained.

(Fifth embodiment)
FIG. 6 shows a fifth embodiment of the oil seal according to the present invention. The oil seal of this embodiment is provided with a plurality of screws on the sealing surface of the oil seal of the fourth embodiment described above.

  In other words, the seal surface 82 of the oil seal 80 of the present embodiment is slightly over the contact area 37 to the atmosphere side in the position of the atmosphere side end, similar to the seal surface 72 of the oil seal 70 of the fourth embodiment described above. An annular recess 84 having an inclined surface 84a similar to the annular recess 74 of the oil seal 70 of the above-described fourth embodiment is formed on the atmosphere side AS of the seal surface 82.

  Since other configurations are the same as those of the oil seal 70 of the fourth embodiment described above, the same reference numerals are given to the main parts in the drawings, and detailed descriptions thereof are omitted.

  According to the oil seal 80 of the present embodiment having such a configuration, in addition to the same effects as the oil seal 70 of the fourth embodiment described above, the same effects as the oil seal 60 of the third embodiment described above are obtained. Play.

  In addition, this invention is not limited to each embodiment mentioned above, A various change is possible as needed.

10, 50, 60, 70, 80 Oil seal 20 Reinforcement ring 21 Cylindrical portion 32 Seal lip 35, 72, 82 Seal surface 35a, 72a, 82a Lip tip 37 Contact area 38 Non-contact area 39 Lumbar 39a Base 40, 52, 64 , 75 Reinforcement convex part 54 Wide part 56 Auxiliary screw groove 62, 86 Screw AS Atmosphere side OS Sealing side H Housing S Rotating shaft

Claims (2)

An oil seal having a seal lip whose lip tip is slidably in close contact with a rotating shaft,
The seal lip extends in the axial direction to a non-contact area formed on the atmosphere side from the contact area where the seal lip contacts the rotating shaft, and is on the atmosphere side. A plurality of reinforcing protrusions that are not in contact with the rotating shaft disposed inside the base when the waist of the seal lip elastically deforms at the end are integrally formed at intervals along the circumferential direction ,
At least one end in the axial direction of the reinforcing convex part is formed with a wide part whose width increases toward the outer side in the axial direction,
The oil seal according to claim 1, wherein a plurality of auxiliary screw grooves are formed on a surface of the reinforcing convex portion to guide a sealing fluid existing in a region where the reinforcing convex portion is formed to a sealing side when the rotary shaft rotates . On the seal surface of the seal lip, there are formed a plurality of screws that exhibit a pumping action that pushes back a sealing fluid that attempts to leak from the sealing side to the atmosphere side when the rotating shaft rotates,
2. The oil seal according to claim 1, wherein an end portion of the reinforcing convex portion on a sealing side is disposed closer to an atmosphere side than an atmosphere side end portion of the plurality of screws.

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