CN108071691B

CN108071691B - Sealing structure

Info

Publication number: CN108071691B
Application number: CN201711075531.7A
Authority: CN
Inventors: 吉田谕史; 井形幸夫
Original assignee: JTEKT Corp; Koyo Sealing Techno Co Ltd
Current assignee: JTEKT Corp; Koyo Sealing Techno Co Ltd
Priority date: 2016-11-07
Filing date: 2017-10-31
Publication date: 2020-11-24
Anticipated expiration: 2037-10-31
Also published as: TWI745470B; TW201818006A; CN108071691A; DE102017125362A1

Abstract

The seal structure (1) includes a first member (11), a second member (6) configured to rotate relative to the first member (11), and a seal member (7) attached to the first member (11). The seal member (7) includes: a first lip (31) comprising a contact portion in contact with a first sealing surface (41) of the second component (6); and a first pressing member (51) configured to press the first lip (31) toward the first sealing surface (41). In the first lip (31) are provided: an accommodating space (S) accommodating the first pressing member (51); and an opening (A) through which the accommodation space (S) is opened in the axial direction. The width of the opening (A) is reduced due to elastic deformation of the contact portion caused when the contact portion contacts the first sealing surface (41).

Description

Sealing structure

Technical Field

The present invention relates to a seal structure provided between two members configured to rotate relative to each other, for example, between a trunnion and a bearing cup of a cross joint.

Background

For example, in a spindle device of a rolling mill, or in a drive shaft of an automobile, a cross joint serving as a universal joint is used as a joint portion between one shaft and another shaft. This cross joint includes: a spider with four trunnions disposed in a crossed arrangement; bearing cups having a bottomed cylindrical shape and provided on the trunnions, respectively; and a plurality of needle rollers rollably disposed between an outer peripheral surface of each of the trunnions and an inner peripheral surface of a corresponding one of the bearing cups. Further, yokes respectively provided at ends of the shaft are coupled to the bearing cups. Further, a seal structure is provided between the base end portion of each trunnion and the end portion of a corresponding one of the bearing cups so as to: water or the like is prevented from entering a receiving space for the needle roller defined between the trunnion and the bearing cup, and leakage of lubricant from the receiving space to the outside is reduced (see, for example, japanese unexamined patent application publication 2015-124836(JP2015-124836a) and EP patent publication 1783384).

An example of a conventional seal structure, as shown in fig. 8, includes a seal structure including: a slinger 106 attached to the base of the trunnions 104 of the spider; and a seal member 107 attached to an inner peripheral portion of the bearing cup 111. The slinger 106 has: a first seal surface 141 facing a first side (one side) in the axial direction (facing an upward direction in fig. 8); and a second sealing surface 142 and a third sealing surface 143 that face outward in the radial direction of the trunnion 104 (face in the right direction in fig. 8). The seal member 107 includes a first lip 131, a second lip 132, and a third lip 133 that are in contact with a first seal surface 141, a second seal surface 142, and a third seal surface 143, respectively, of the slinger 106. The first to third lips 131 to 133 are firmly fitted to a metal core 134, and the metal core 134 is fixed to the bearing cup 111. Garter spring 152 is engaged to second lip 132, thereby pressing second lip 132 against second sealing surface 142.

As shown in fig. 9, the sealing structure described in EP patent publication 1783384 includes: a seal retainer 218 attached to the base of the trunnion 204; and a seal member 207 fixed to the seal holder 218. The seal member 207 includes a first lip 231 and a second lip 232 that are in sliding contact with the inner peripheral surface of the bearing cup 211. The first and

second lips

231, 232 are securely fitted to a metal core 234, the metal core 234 being secured to the seal holder 218.

In the cross joint described above, the trunnion is slightly moved in the radial direction and in the axial direction within the allowable range of dimensional deviation with respect to the bearing cup while the cross joint is being used. In the seal structure shown in fig. 8, when the elasticity of the first lip 131 has been reduced due to, for example, deterioration caused by long-term use, the first lip 131 can move in a direction away from the first seal surface 141 due to axial movement of the trunnion 104 relative to the bearing cup 111. This may cause a reduction in sealability.

In the seal structure shown in fig. 9, both the first lip 231 and the second lip 232 are in sliding contact with the inner peripheral surface of the bearing cup 211, and therefore the axial movement of the trunnion 204 relative to the bearing cup 211 hardly causes a reduction in sealability. However, when the trunnion 204 moves in the radial direction with respect to the bearing cup 211, the first and

second lips

231 and 232 move in a direction toward the inner peripheral surface of the bearing cup 211 on one side of the trunnion 204 in the radial direction, but the first and

second lips

231 and 232 move in a direction away from the inner peripheral surface of the bearing cup 211 on the other side of the trunnion 204 in the radial direction. For this reason, it is difficult to obtain uniform sealability at both sides of the seal member 207 in the radial direction. As the garter spring (pressing member) 252 applies a biasing force outward in the radial direction to the second lip portion 232, the second lip portion 232 is pressed against the inner peripheral surface of the bearing cup 211. However, since the chucking spring 252 is fitted to the second lip 232 in a compressed state, the chucking spring 252 may be easily deflected, and thus the chucking spring 252 may come out of the groove of the inner circumferential surface of the second lip 232.

Disclosure of Invention

The present invention provides a seal structure configured to: the pressing member is prevented from coming out of the accommodation space while suppressing a decrease in sealability due to axial movement of the trunnion relative to the bearing cup.

A seal structure according to an aspect of the present invention includes a first member, a second member facing the first member in a radial direction, and a seal member having an annular shape. The second member is disposed concentrically with the first member, and the second member is configured to rotate relative to the first member. The sealing member is attached to the first member, and the sealing member is in sliding contact with the second member. The second component has a first sealing surface facing a first side of the second component in a radial direction. The seal member includes a fixing portion fixed to the first member, a first lip portion bonded to the fixing portion, and the first lip portion includes a contact portion in contact with the first seal surface, and a first pressing member configured to press the first lip portion toward the first seal surface. An accommodation space is provided inside the first lip portion, the accommodation space accommodating the first pressing member. The first lip portion has an opening through which the accommodation space is opened toward one side in the axial direction, and the first pressing member is inserted into the accommodation space through the opening. The contact portion is provided on a second side in the radial direction with respect to the accommodation space. The second side in the radial direction is the first sealing surface side in the radial direction. The width of the opening is reduced due to elastic deformation of the contact portion caused when the contact portion comes into contact with the first sealing surface.

With the foregoing configuration, the contact portion of the first lip is in contact with the first seal surface facing the first side in the radial direction. Therefore, even when the second member is moved in the axial direction relative to the first member, the sealability provided by the first lip is not reduced. In addition, when the contact portion of the first lip portion is brought into contact with the first sealing surface, the width of the opening (into which the first pressing member is inserted into the accommodating space) in the first lip portion is reduced. Therefore, the first pressing member is prevented from coming out of the accommodating space.

The contact portion may include a side edge. The side edge may constitute a peripheral edge of a radially second lateral end of the opening. In a first state where the contact portion is not brought into contact with the first sealing surface, a side edge may be provided on the second side in the radial direction with respect to the first pressing member. In a second state where the contact portion is in contact with the first sealing surface, the side edge may be disposed on the first side in the radial direction with respect to a radial second side end portion of the first pressing member.

With the foregoing configuration, in the first state in which the contact portion of the first lip is not brought into contact with the first sealing surface, the width of the opening is kept as wide as possible to facilitate insertion of the first pressing member into the accommodating space, while in the second state in which the contact portion is brought into contact with the first sealing surface, the width of the opening is kept small, which reliably prevents the first pressing member from coming out of the accommodating space.

The second component may have a second sealing surface facing the second side in the radial direction. The sealing member may further include a second lip portion that is coupled to the fixing portion and is in contact with the second sealing surface, and a second pressing member configured to press the second lip portion toward the second sealing surface.

With the foregoing configuration, when the second member is moved in the radial direction relative to the first member, even if the first lip is moved in the direction away from the first sealing surface on one side in the radial direction, the second lip is still moved in the direction toward the second sealing surface, and even if the second lip is moved in the direction away from the second sealing surface on the other side in the radial direction, the first lip is still moved in the direction toward the first sealing surface. Therefore, substantially uniform sealability can be obtained on both sides of the seal member in the radial direction.

The second component may have a third sealing surface facing the second side in the radial direction. The sealing member may further include a third lip portion, the third lip portion being coupled to the fixing portion, and the third lip portion being in contact with the third sealing surface. With this configuration, the third lip portion can increase sealability in addition to the first and second lip portions.

One of the first sealing surface and the second sealing surface may face outward in the radial direction. The other of the first sealing surface and the second sealing surface may face inward in the radial direction and be disposed outward of the one sealing surface in the radial direction, with a space being left between the first sealing surface and the second sealing surface. With this configuration, the seal member can be inserted between the first seal surface and the second seal surface disposed with a space left therebetween in the radial direction, and the first lip portion and the second lip portion can be brought into contact with the first seal surface and the second seal surface, respectively. In addition, the arrangement of the first and second sealing surfaces of the second member can be simplified, and the first and second sealing surfaces can be accurately formed.

One of the first sealing surface and an integral sealing surface, which includes the second sealing surface and the third sealing surface, may face outward in the radial direction. The other of the first sealing surface and the integral sealing surface may face inward in the radial direction and be disposed outward of the one sealing surface in the radial direction, with a space being left between the first sealing surface and the integral sealing surface. The second sealing surface and the third sealing surface constituting the integral sealing surface may be disposed adjacent to each other in the axial direction. With this configuration, the seal member can be inserted between the first seal surface and the integral seal surface including the second seal surface and the third seal surface which are provided with a space therebetween in the radial direction, and the first to third lips can be brought into contact with these seal surfaces. In addition, the arrangement of the first to third sealing surfaces of the second member can be simplified, and the first to third sealing surfaces can be accurately formed.

With the sealing structure of the invention, it is feasible to: the pressing member is prevented from coming out of the accommodation space while suppressing a decrease in sealability due to axial movement of the trunnion relative to the bearing cup.

Drawings

Features, advantages and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

fig. 1 is a partially exploded perspective view of a cross joint provided with a sealing structure according to a first embodiment;

FIG. 2 is a cross-sectional view of the seal structure;

FIG. 3 is a cross-sectional view of a seal member of the seal structure;

FIG. 4 is a cross-sectional view showing the effect of the first lip;

FIG. 5 is a cross-sectional view of a seal member of a seal structure according to a second embodiment;

FIG. 6 is a cross-sectional view of a seal member of a seal structure according to a third embodiment;

FIG. 7 is a cross-sectional view of a seal member of a seal structure according to a fourth embodiment;

fig. 8 is a sectional view of a sealing structure according to the related art; and is

Fig. 9 is a sectional view of a sealing structure according to another related art.

Detailed Description

Hereinafter, example embodiments of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a partially exploded perspective view of a oldham coupling provided with a seal structure according to a first embodiment. For example, in a spindle device (not shown) of a rolling mill, the cross joint 20 is used. As shown in fig. 1, the cross joint 20 includes: a spider 2 with four trunnions 4; roller bearing units 5 provided on these trunnions 4, respectively; and a pair of yokes 17.

The spider 2 comprises: a base 3 disposed at the center of the spider 2; and the four trunnions 4 extending from the base 3 in four respective directions along axes X and Z which are perpendicular to each other. The spider 2 is rotatable about a central axis C which passes through the centre of the base 3 and which is perpendicular to the axis X and the axis Z of the trunnion 4. The spider 2 has lubricant supply paths 13 provided in a crossed arrangement along the axis X and the axis Z to supply lubricant into the roller bearing unit 5.

Each roller bearing unit 5 includes a plurality of needle rollers 9 and a bearing cup 11. The needle roller 9 is rollably disposed along an outer peripheral surface of each of the aforementioned trunnions 4. The bearing cup 11 has a bottomed cylindrical shape, and is fitted onto the outer peripheral surface of the trunnion 4 via the needle roller 9. Therefore, the needle rollers 9 roll on the inner peripheral surface of the bearing cup 11 (this inner peripheral surface of the bearing cup 11 serves as an outer ring track) and on the outer peripheral surface of the trunnion 4 (the outer peripheral surface of the trunnion 4 serves as an inner ring track), and therefore, the bearing cup 11 is able to swing about the axis Z of the trunnion 4. A washer 10 is provided between the distal end surface of the trunnion 4 and the bottom surface of the bearing cup 11. Inside the needle roller 9 in the axis Z direction, a roller guide 8, a seal member 7, and a slinger 6 are provided. The seal member 7, the slinger 6 (an example of the "second member"), and the bearing cup 11 (an example of the "first member") constitute the seal structure 1 according to the present invention.

Fig. 2 is a cross-sectional view of the seal structure. Fig. 3 is a sectional view showing a seal member which is not brought into contact with the slinger (i.e., a seal member which is not fitted to the slinger). The seal structure 1 is provided so that: water or the like is prevented from entering the accommodating space for the needle roller 9 defined between the trunnion 4 and the bearing cup 11, and leakage of lubricant from the accommodating space to the outside is reduced. In this specification, the lower side in fig. 2 will be referred to as "first side in the axial direction" or "axial first side", and the upper side in fig. 2 will be referred to as "second side in the axial direction" or "axial second side". However, these terms indicate relative directions along the axial direction rather than indicating absolute specific directions along the axial direction, and the first side and the second side may be interchanged. The same can be applied to the "first side in the radial direction (radial first side)" and the "second side in the radial direction (radial second side)".

The slinger 6 included in the seal structure 1 has an annular shape, and is fitted onto the outer peripheral surface of the base end portion of the trunnion 4. The slinger 6 has a seal surface 41, a seal surface 42 and a seal surface 43 which are in contact with the lip 31, the lip 32 and the lip 33 of the seal member 7, respectively. The slinger 6 is a one-piece component comprising: a slinger body 6a, the slinger body 6a having a tubular shape, and the slinger body 6a extending along the outer peripheral surface of the trunnion 4; a first extension 6b, the first extension 6b extending radially outward on an axial first side (lower side in fig. 2) of the slinger main body 6 a; and a second extension 6c extending from a distal end side of the first extension 6b toward a second side (upper side in fig. 2) in the axial direction.

The outer peripheral surface of the slinger main body 6a has a second seal surface 42 and a third seal surface 43 disposed adjacent to each other in the axial direction. The inner peripheral surface of the second extension portion 6c has a first seal surface 41. The slinger 6 further includes a third extension 6d extending radially outwardly from the second extension 6 c. The outer peripheral surface of the second extension portion 6c and the axial second side surface of the third extension portion 6d face the end of the bearing cup 11 with a gap left between the outer peripheral surface of the second extension portion 6c and the axial second side surface of the third extension portion 6d and the end of the bearing cup 11. This gap is a seal gap configured to prevent water or the like from entering between the slinger 6 and the bearing cup 11.

The seal member 7 includes a metal core 34 (an example of a "fixing portion") and

lips

31, 32, 33. The metal core 34 is fitted to the inner peripheral surface of the bearing cup 11, thereby being fixed to the inner peripheral surface of the bearing cup 11. The metal core 34 includes a first metal core 34a including a first cylindrical portion 34a1 and a first annular portion 34a2 bent radially inward from an axial second side end portion of the first cylindrical portion 34a1, and a second metal core 34b including a second cylindrical portion 34b1 and a second annular portion 34b2 bent radially inward from an axial first side end portion of the second cylindrical portion 34b 1. The second cylindrical portion 34b1 is placed on the radially inner side of the first cylindrical portion 34a1, and the second metal core 34b is fixed to the first metal core 34a by swaging an axial first side end portion of the first cylindrical portion 34a 1.

The

lips

31, 32, 33 are constituted by a first lip 31, a second lip 32, and a third lip 33, respectively, which are bonded to the metal core 34. The first and

third lips

31, 33 are bonded to the second annular portion 34b2 of the second metal core 34b, and the second lip 32 is bonded to the first annular portion 34a2 of the first metal core 34 a.

The second lip 32 extends from the first annular portion 34a2 toward the first side in the axial direction. The radially inner side surface of the second lip 32 is in contact with the second seal surface 42 of the slinger 6. A recess 32a is provided in a radially outer side surface of the second lip 32, and a garter spring 52 (one example of a "second pressing member") is provided in the recess 32 a. The garter spring 52 is a coil spring formed in a ring shape, and the garter spring 52 is accommodated in the recess 32a of the second lip 32 while being elastically deformed in the stretching direction. The garter spring 52 presses the second lip 32 toward the second sealing surface 42 by attempting to elastically return to its original shape in the compression direction.

The third lip 33 extends from a radially inner end of the second annular portion 34b2 toward the first side in the axial direction. A radially inner side surface of the third lip 33 is in contact with the third seal surface 43 of the slinger 6. The third sealing surface 43 is an inclined surface (tapered surface) having an outer diameter gradually decreasing from the first side toward the second side in the axial direction.

The first lip 31 includes: a first portion 31a extending from an axial first side surface of the second annular portion 34b2 toward a first side in the axial direction; a second portion 31b extending radially outward from an extending end (axial first side end portion) of the first portion 31 a; and a third portion 31c extending from an extending end (radially outer end) of the second portion 31b toward the second side in the axial direction. A radially outer side surface (outer peripheral surface) of the third portion 31c is in contact with the first seal surface 41 of the slinger 6. Therefore, the third portion 31c is an example of a contact portion that contacts the first seal surface 41.

A garter spring 51 (an example of a "first pressing member") is accommodated in a space S (an example of an "accommodating space") surrounded by the first portion 31a, the second portion 31b, and the third portion 31 c. Further, an opening a is defined between the first portion 31a and the third portion 31c, through which the chucking spring 51 is inserted into the accommodating space S. The opening a opens toward the second side in the axial direction. The garter spring 51 is a coil spring formed in a ring shape, and the garter spring 51 is accommodated in the accommodation space S while being elastically deformed in the compression direction. The garter spring 51 presses the third portion 31c toward the first sealing surface 41 by attempting to elastically recover its original shape in the stretching direction.

Fig. 4 is a sectional view showing the effect of the first lip. As shown by the solid line in fig. 4, in a first state in which the third portion 31c is not brought into contact with the first seal surface 41 of the slinger 6, the third portion 31c of the first lip 31 is inclined radially outward. In this first state, the width W1 of the opening a between the first portion 31a and the third portion 31c is relatively wide. Specifically, in the first state, the radial position a of the inner peripheral edge 31d ("one example of a side edge", is one edge of the opening a) of the distal end of the third portion 31c is disposed radially outward of the radial position b of the radially outer end portion of the garter spring 51. Therefore, the chucking spring 51 is easily inserted into the accommodating space S through the opening a.

On the other hand, as shown by the two-dot chain line in fig. 4, in the second state where the third portion 31c is in contact with the first seal surface 41, the third portion 31c has been elastically deformed radially inward, and the width W2 is reduced to a width smaller than the width W1, the width W2 being the width of the opening a between the first portion 31a and the third portion 31c in the second state, and the width W1 being the width of the opening a between the first portion 31a and the third portion 31c in the first state. Therefore, in the second state, the radial position a' of the distal inner peripheral edge 31d of the third portion 31c is disposed radially inward of the radial position b of the radially outer end portion of the garter spring 51. For this reason, the garter spring 51 is not allowed to easily come out of the housing space S, so that the first lip 31 can be reliably held in contact with the first seal surface 41. Specifically, the garter spring 51 has been elastically deformed in the compression direction, so that the garter spring 51 is easily deflected and easily comes out of the accommodation space S. However, reducing the width of the opening a reliably prevents the chucking spring 51 from coming out of the housing space S.

The inner peripheral edge 31d of the distal end of the third portion 31c of the first lip 31 is provided with a radially inwardly bulging portion 31c 1. Due to the provision of the raised portion 31c1, it is possible to: when the third portion 31c comes into contact with the first seal surface 41, the width W2 of the opening a is made as small as possible while allowing the third portion 31c to be easily elastically deformed inward in the radial direction.

The seal member 7 of the present embodiment is configured such that: the first lip 31 is in contact with a first sealing surface 41 facing inward in the radial direction, and the second lip 32 and the third lip 33 are in contact with a second sealing surface 42 and a third sealing surface 43 facing outward in the radial direction, respectively. For this reason, even when the trunnion 4 moves in the axial direction with respect to the bearing cup 11, the sealability is not reduced.

When the trunnion 4 moves in the radial direction with respect to the bearing cup 11, on one side of the trunnion 4 in the radial direction, the first lip 31 moves in a direction away from the first sealing surface 41, while the second lip 32 and the third lip 33 move in a direction toward the second sealing surface 42 and the third sealing surface 43. At this time, on the other side of the trunnion 4 in the radial direction, the second lip 32 and the third lip 33 move in a direction away from the second sealing surface 42 and the third sealing surface 43, while the first lip 31 moves in a direction toward the first sealing surface 41. For this reason, substantially uniform sealability can be obtained on both sides of the seal member 7 in the radial direction.

The slinger 6 has: a second seal surface 42 and a third seal surface 43 provided in the outer peripheral surface of the slinger main body 6 a; and a first seal surface 41 disposed radially outward of the second seal surface 42 and the third seal surface 43 and in the inner peripheral surface of the second extension portion 6 c. Thus, the second and third sealing surfaces 42, 43 and the first sealing surface 41 face each other in the radial direction with a space left therebetween, providing a space for the sealing member 7 between the second and third sealing surfaces 42, 43 and the first sealing surface 41. When the seal member 7 is inserted into the space, the lips 31 to 33 can come into contact with the first seal surface 41 and the second and third seal surfaces 42 and 43, respectively. The first sealing surface 41 faces in a radial direction opposite to the radial direction that the second and third sealing surfaces 42, 43 face. The first seal surface 41 and the third seal surface 43 are provided at positions overlapping each other in the axial direction, so that the size of the seal structure 1 in the axial direction can be made as small as possible.

Fig. 5 is a cross-sectional view of a seal member of a seal structure according to a second embodiment. The seal member 7 of the present embodiment is different from the seal member 7 of the first embodiment in that: the sealing member 7 of the present embodiment does not include the third lip 33. Other configurations are the same as those in the first embodiment, and thus detailed description thereof will be omitted.

Fig. 6 is a sectional view of a seal member of a seal structure according to a third embodiment. The seal member 7 of the present embodiment is different from the seal member 7 of the first embodiment in that: the sealing member 7 of the present embodiment does not include the third lip 33. Further, the first lip 31 is in contact with the outer peripheral surface of the slinger main body 6 a. That is, the first seal surface 41 is provided in the outer peripheral surface of the slinger main body 6a, and is arranged adjacent to the second seal surface 42 at a position on the first side of the second seal surface 42 in the axial direction. The first lip 31 includes: a first portion 31a extending from the second annular portion 34b2 toward the first side in the axial direction; a second portion 31b extending radially inward from an extending end of the first portion 31 a; and a third portion 31c extending from an extending end of the second portion 31b toward a second side in the axial direction. The garter spring 51 is accommodated in an accommodation space S surrounded by the first portion 31a, the second portion 31b, and the third portion 31 c. The garter spring 51 of the present embodiment is attached to the first lip 31 in a stretched state, and by attempting to elastically deform in the compression direction, the garter spring 51 presses the third portion 31 c. In addition, the width of the opening a defined between the first portion 31a and the third portion 31c varies between a first state (in which the third portion 31c is not brought into contact with the first seal surface 41 of the slinger 6) and a second state (in which the third portion 31c is brought into contact with the first seal surface 41 and the third portion 31c is elastically deformed radially outward as compared with the first state). Specifically, the width of the opening a between the first portion 31a and the third portion 31c in the second state is reduced to a width smaller than the width of the opening a between the first portion 31a and the third portion 31c in the first state.

This embodiment produces substantially the same advantageous effects as those in the first embodiment. However, the first lip 31 and the second lip 32 are in contact with the first sealing surface 41 and the second sealing surface 42, respectively, which face the same side in the radial direction. Thus, when the trunnion 4 moves in the radial direction with respect to the bearing cup 11, on one side of the trunnion 4 in the radial direction, both the

lips

31, 32 move in a direction away from the sealing surfaces 41, 42. For this reason, the first embodiment has an advantage over the third embodiment from the viewpoint of uniformity of sealability. Note that the garter spring 51 of the present embodiment is attached to the first lip 31 in a stretched state, and therefore the possibility that the garter spring 51 will come out of the accommodation space S is lower than that in the first embodiment. In addition, the reduction in the width of the opening a further reduces the possibility that the chucking spring 51 will come out of the housing space S.

Fig. 7 is a sectional view of a seal member of a seal structure according to a fourth embodiment. The seal member 7 of the present embodiment has an opening a which is provided in the first lip 31 and which is open toward a first side in the axial direction (lower side in fig. 7). Namely, the first lip 31 includes: a base portion 31g extending from the second annular portion 34b2 toward the first side in the axial direction; and a fourth portion 31e and a fifth portion 31f extending in a bifurcated manner from the base portion 31 g. The fifth portion 31f is an example of a contact portion that contacts the first seal surface 41.

In the present embodiment, the fifth portion 31f is elastically deformed radially inward by coming into contact with the first seal surface 41, so that the width of the opening a is reduced. Therefore, the present embodiment produces substantially the same advantageous effects as those in the first embodiment.

Note that the present invention is not limited to the foregoing embodiments, and can be implemented in appropriately modified embodiments. For example, although the first and second sealing surfaces extend along (parallel to) the axial direction in the foregoing embodiments, the first and second sealing surfaces may be slightly inclined with respect to the axial direction. Although the third sealing surface is slightly inclined with respect to the axial direction in the foregoing embodiment, the third sealing surface may extend along the axial direction. In the third embodiment, the second seal surface may be provided in a surface facing inward in the radial direction, and the second lip may be brought into contact with the second seal surface from the inner side in the radial direction.

The sealing member may be configured to be secured to the trunnion and to make contact with the bearing cup. The seal structure of the present invention may be provided at a position other than a position between the trunnion and the bearing cup of the cross joint.

Claims

1. A sealing structure, comprising:

a first member (11);

a second member (6) facing the first member (11) in a radial direction, the second member (6) being disposed concentrically with the first member (11), and the second member (6) being configured to rotate relative to the first member (11); and

a sealing member (7) having an annular shape, the sealing member (7) being attached to the first member (11), and the sealing member (7) being in sliding contact with the second member (6), wherein:

the second component (6) having a first sealing surface (41), the first sealing surface (41) facing inwardly of the second component (6) in the radial direction;

the seal member (7) includes a fixing portion (34), a first lip portion (31), and a first garter spring (51), the fixing portion (34) being fixed to the first member (11), the first lip portion (31) being joined to the fixing portion (34), and the first lip portion (31) including a contact portion that contacts the first seal surface (41) at an outer side in the radial direction, the first lip portion (31) not contacting the second member (6) at the inner side in the radial direction, the first garter spring (51) being configured to press the first lip portion (31) toward the first seal surface (41);

-providing an accommodation space (S) inside the first lip (31), said accommodation space (S) accommodating the first garter spring (51);

the first lip (31) has an opening (a) through which the housing space (S) is opened toward one of one side in an axial direction and the other side in the axial direction, and the first garter spring (51) is inserted into the housing space (S) through the opening (a);

the contact portion is disposed on the outer side in the radial direction with respect to the accommodation space (S);

the outer side in the radial direction is the first seal surface (41) side in the radial direction;

reducing the width of the opening (A) due to elastic deformation of the contact portion inward in the radial direction caused when the contact portion comes into contact with the first sealing surface (41); and is

The first garter spring (51) is accommodated in the accommodation space (S) while being elastically deformed in a compression direction.

2. The seal structure of claim 1, wherein:

the contact portion includes a side edge (31 d);

said side edge (31d) constituting a peripheral edge of a radially outer end of said opening (A);

the side edge (31d) is disposed on the outer side in the radial direction with respect to the first garter spring (51) in a first state where the contact portion is not brought into contact with the first seal surface (41); and is

In a second state where the contact portion is in contact with the first seal surface (41), the side edge (31d) is disposed on the inner side in the radial direction with respect to a radially outer end portion of the first garter spring (51).

3. The seal structure according to claim 1 or 2, characterized in that:

the second member (6) has a second sealing surface (42), the second sealing surface (42) facing the outside in the radial direction; and is

The sealing member (7) further includes a second lip (32) and a second pressing member (52), the second lip (32) being joined to the fixing portion (34), and the second lip (32) being in contact with the second sealing surface (42), the second pressing member (52) being configured to press the second lip (32) toward the second sealing surface (42).

4. The seal structure of claim 3, wherein:

the second member (6) has a third sealing surface (43), the third sealing surface (43) facing the outside in the radial direction; and is

The sealing member (7) further comprises a third lip (33), the third lip (33) is joined to the fixing portion (34), and the third lip (33) is in contact with the third sealing surface (43).

5. The seal structure of claim 3, wherein:

the second sealing surface (42) faces the outer side in the radial direction; and is

The first sealing surface (41) faces the inward direction in the radial direction, and the first sealing surface (41) is disposed outward of the second sealing surface (42) in the radial direction, with a space left between the first sealing surface (41) and the second sealing surface (42).

6. The seal structure of claim 4, wherein:

the second sealing surface (42) and the third sealing surface (43) face the outer side in the radial direction;

the first sealing surface (41) faces the inward direction in the radial direction, and the first sealing surface (41) is disposed outward of the second sealing surface (42) and the third sealing surface (43) in the radial direction, with a space left between the first sealing surface (41) and an integral sealing surface that includes the second sealing surface (42) and the third sealing surface (43); and is

The second sealing surface (42) and the third sealing surface (43) constituting the integral sealing surface are disposed adjacent to each other in the axial direction.