TWI763948B - Sealing structure - Google Patents

Abstract

A sealing structure (1) includes a seal member (7) that includes a lip portion (31) and a pressing member (51). The lip portion includes a contact portion (31c), a base portion (31a), and a connecting portion (31b). The contact portion includes a confronting surface (31c2). The pressing member is arranged in a space surrounded by the contact portion, the base portion, and the connecting portion, and presses the confronting surface to the sealing surface side. The confronting surface includes a full contact region (R1) that is in contact with the sealing surface in an entire circumference on a side of an outer portion of the lubrication space in the direction along the sealing surface, and a partial contact region (R2) that is in contact with the sealing surface discontinuously in a circumferential direction on the lubrication space side in the direction along the sealing surface.

Description

sealing structure

The present invention relates to a sealing structure which is arranged between two members which rotate relative to each other. The two components are, for example, the shaft portion and the bearing cup of a cruciform joint.

Cross joints are used, for example, in mandrel arrangements for steel rolling mills or drive shafts for automobiles as universal joints in the joints between the shafts. The cross joint includes a joint cross, a bearing cap with a bottom cylindrical shape, and a plurality of needle rollers. In the joint cross, the four shaft portions are provided in a cross shape. A bearing cap covers each of the shaft portions. The needle rollers are arranged between the outer peripheral surface of each of the shaft portions and the inner peripheral surface of the bearing cap so that the needle rollers can roll. A yoke provided at the end of each of the shaft portions is connected with the bearing cap. In addition, a sealing structure is provided between the base end of the shaft portion and the end of the bearing cap so as to prevent water and the like from entering the accommodating space for the needle roller (the accommodating space is formed between the shaft portion and the bearing cap) and also suppress the leakage of lubricant from the containing space to the outside (for example, see European Patent Publication No. 1783384).

The inventor of the present application previously proposed a sealing structure as shown in FIG. 11 (Japanese Patent Application No. 2016-217292). The sealing structure includes an annular sealing member 107 mounted on the bearing cap 111 in sliding contact with a slinger 106 . The slinger 106 has a radially inward facing sealing surface 141 . The sealing member 107 includes a cored bar 134 fixed to the bearing cap 111 , a lip 131 attached to the cored bar 134 and in contact with the sealing surface 141 , and an oil seal spring that presses the lip 131 to the sealing surface 141 side (garter spring) 151.

When grease is used to lubricate the space (lubricating space) between the oil retaining ring 106 and the bearing cap 111, in order to replace the grease in the lubricating space with new grease at the time of maintenance or the like, it must be The old grease is discharged from the lips 131 to the outside. However, in the case of the sealing structure shown in FIG. 11, when new grease is supplied to the lubrication space, a force is applied to press the lip 131 against the sealing surface 141, as indicated by arrow c in FIG. 12, And the side surface 131c2 of the lip portion 131 facing the sealing surface 141 is in strong contact with almost the entire sealing surface 141 . Therefore, it is difficult to drain the grease out of the lubrication space by allowing the grease to pass between the lip 131 and the sealing surface 141 .

The present invention provides a sealing structure to improve the performance of draining old grease when new grease is supplied to a sealing structure that seals a sealed space filled with grease.

An aspect of the present invention provides a sealing structure including a first member, a second member, and a sealing member. The second member is arranged coaxially with the first member and arranged to rotate relative to the first member. The second member faces the first member in the radial direction. The sealing member has an annular shape and is mounted on the first member in sliding contact with a sealing surface provided in the second member. The first member and the second member define a lubricating space filled with grease. The sealing member includes a lip and a pressing member. The lip portion includes: a contact portion including a confronting surface facing the sealing surface; a base portion positioned on an opposite side of the contact portion from the sealing surface; and a connecting portion connecting the contact portion along the The end of the sealing surface oriented on the lubricating space side is connected to the seat portion. The pressing member is arranged in the space surrounded by the contact portion, the base portion, and the connection portion. The pressing member presses the opposing surface to the side of the sealing surface. The opposing surfaces include full contact areas and partial contact areas. The full contact area is constructed to be in contact with the sealing surface over the entire circumference on the side outside the lubrication space in the direction of the sealing surface when the grease is supplied to the lubrication space. The partial contact area is constructed in discontinuous contact with the sealing surface in the circumferential direction on the lubrication space side in the direction of the sealing surface.

With this configuration, even when the lip is pressed against the sealing surface by the grease supplied into the lubricating space, since the part of the contact area of the opposing surface has a portion that is not in contact with the sealing surface, the grease is self-lubricating space side This part is entered and the grease pushes up the full contact area and is drained out of the lubrication space. Therefore, it is possible to improve the efficiency of draining old grease when new grease is supplied. Furthermore, due to the complete contact area on the opposing surfaces, it is possible to ensure a sufficient sealing effect.

In the sealing structure, the boundary between the full contact area and the partial contact area may be positioned outside the lubrication space from the end of the pressing member, which is located at a position on the lubrication space side in the direction of the sealing surface. on the side. With this configuration, it is possible to improve the performance of draining grease.

In the sealing structure, the boundary may be configured to be on the lubrication space side in the direction along the sealing surface from the center of the pressing member. With this configuration, it is possible to improve the performance of draining grease while ensuring sealing performance in the full contact area.

In the sealing structure, grooves may be provided in partial contact areas of the opposing surfaces, the grooves extending from the lubricating space side to the outer side of the lubricating space in the direction along the sealing surface. With this configuration, when grease is supplied to the lubrication space, the old grease inside the lubrication space enters the groove, pushes up the full contact area, and is drained out of the lubrication space.

In the sealing structure, the cross-sectional area of the groove may be larger on the lubrication space side in the direction along the sealing surface. With this configuration, the grease becomes easier to enter the groove, and the full contact area is more easily pushed up when the grease is supplied, thereby facilitating the discharge of the grease.

In the sealing structure, the plurality of protrusions may be arranged at intervals in the circumferential direction in partial contact areas of the opposing surfaces. By providing the protrusion, a gap is formed between the opposing surfaces of the contact portion and the sealing surface, and when grease is supplied, the grease is allowed to enter the gap, pushes up the full contact area, and is discharged.

In the sealing structure, the protruding portion may be configured such that the end portion of the self-pressing member is on the lubricating space side, the end portion being positioned on the lubricating space side in the direction along the sealing surface. With this configuration, it can be ensured that the end self-sealing surface of the contact portion on the lubricating space side is raised, and the gap is thus formed. Grease is then allowed to enter the gap.

With the sealing structure according to the present invention, in the sealing structure for sealing the sealed space filled with grease, it is possible to improve the performance of draining old grease when new grease is supplied.

Next, embodiments of the present invention are described with reference to the drawings. first embodiment

FIG. 1 is a partially exploded perspective view of a cross joint to which the sealing structure according to the first embodiment is applied. Fig. 2 is a side view (partial sectional view) of the cross joint. The cross joint 20 is used, for example, in a mandrel arrangement (not shown) of a steel rolling mill. As shown in FIG. 1 , the cross joint 20 includes a joint cross 2 having four shaft portions 4 , a roller bearing portion 5 arranged in each of the shaft portions 4 , and a pair of yokes 17 .

The joint cross 2 includes a base portion 3 provided at the center, and four shaft portions 4 extending from the base portion 3 in four directions along the axes X and Z orthogonal to each other. The joint cross 2 is rotatable around a central axis C passing through the center of the base portion 3 and is orthogonal to the axis X and the axis Z of the shaft portion 4 . In the joint cross 2, the grease channels 13 are arranged to have a cross shape along the axis X and the axis Z. Grease channels 13 are used to supply lubricant into the roller bearing portion 5 .

As shown in FIG. 2, grease holes 3a, 11a are provided in the side surface of the base portion 3 of the joint cross 2, and the bearing cap 11 (described later) of the roller bearing portion 5, respectively. The grease holes 3 a , 11 a are connected to the grease channel 13 . The lubricant is supplied into the roller bearing portion 5 via the grease holes 3 a, 11 a and the grease passage 13 . In this embodiment, grease is used as the lubricant. Additionally, the grease may be supplied continuously while the device having the cross joint 20 is operating, or the grease may be supplied periodically (eg, every to three months).

The roller bearing portion 5 includes a shaft portion 4 , a plurality of needle rollers 9 , and a bearing cap 11 . The needle rollers 9 are arranged along the outer peripheral surface of each of the shaft portions 4 so that the needle rollers 9 can roll. The bearing cap 11 is formed in a bottom cylindrical shape and is fitted to the outer peripheral surface of the shaft portion 4 via the needle rollers 9 . Therefore, the needle roller 9 rolls by using the inner peripheral surface of the bearing cap 11 as the outer ring raceway and the outer peripheral surface of the shaft portion 4 as the inner ring raceway. Therefore, the bearing cap 11 can swing around the axis Z of the shaft portion 4 .

The spacer 10 is provided between the distal end surface of the shaft portion 4 and the bottom surface of the bearing cap 11 . The roller guide 8 , the seal member 7 and the slinger 6 are arranged on the inner side of the needle roller 9 in the axis Z direction. The sealing member 7 , the oil deflector (second member) 6 and the bearing cover (first member 11 ) constitute the sealing structure 1 according to the present invention.

FIG. 3 is a cross-sectional view of the sealing structure 1 . 4 is a cross-sectional view of the seal member 7 in a state in which the seal member 7 is not in contact with the oil deflector 6 (in other words, in a state in which the seal member 7 is in a natural state). The sealing structure 1 is provided to prevent the entry of water and the like into the lubricating space, and also to prevent the leakage of lubricant from the lubricating space to the outside. The lubricating space is a space in which the needle roller 9 is arranged between the shaft portion 4 and the bearing cover 11 and is filled with grease. In this specification, the lower side in FIG. 3 is referred to as the “first side in the axial direction”, and the upper side in FIG. 3 is referred to as the “second side in the axial direction”. However, they do not denote absolute exact directions with respect to the axial direction, but rather they denote relative directions. Therefore, the first side and the second side can be replaced with each other. The same applies to "first side in radial direction" and "second side in radial direction".

The oil deflector 6 included in the sealing structure 1 is formed in an annular shape, and is fitted to the outer peripheral surface of the base end portion of the shaft portion 4 . In the slinger 6, sealing surfaces 41, 42, 43 are formed, and the lips 31, 32, 33 of the sealing member 7 are brought into contact with the sealing surfaces 41, 42, 43, respectively. The oil deflector 6 also integrally includes an oil deflector body 6a, a first extension portion 6b, and a second extension portion 6c. The slinger body 6 a is formed to have a cylindrical shape along the outer peripheral surface of the shaft portion 4 . The first extension 6b extends radially outward on the first side (lower side in FIG. 3 ) in the axial direction of the slinger body 6a. The second extension portion 6c extends from the distal end side of the first extension portion 6b to the second side (upper side in FIG. 3 ) in the axial direction.

On the outer peripheral surface of the slinger body 6a, a second sealing surface 42 and a third sealing surface 43 are formed side by side in the axial direction. Also, on the inner peripheral surface of the second extension portion 6c, a first sealing surface 41 is formed. The first sealing surface 41 is formed along the axial direction. Therefore, in this embodiment, the direction along the first sealing surface 41 coincides with the axial direction.

In the oil deflector 6, a third extension 6d is provided. The third extension 6d extends further radially outward from the second extension 6c. The outer peripheral surface of the second extension portion 6c and the side surface of the third extension portion 6d on the second side in the axial direction face the end of the bearing cap 11 via a gap. The gap serves as a sealing gap to prevent water and the like from entering between the slinger 6 and the bearing cover 11 .

The sealing member 7 includes a mandrel (fixed portion) 34 and lip portions 31 , 32 , and 33 . When the mandrel 34 is fitted to the inner peripheral surface of the bearing cap 11, the mandrel 34 is fixed. The mandrel 34 includes a first mandrel 34a and a second mandrel 34b. The first mandrel 34 has a first cylindrical portion 34a1, and a first circular portion 34a2 bent radially inward from an end portion of the first cylindrical portion 34a1 on the second side in the axial direction. The second mandrel 34b has a second cylindrical portion 34b1, and a second circular portion 34b2 bent radially inward from an end portion of the second cylindrical portion 34b1 on the first side in the axial direction. The second cylindrical portion 34b1 is laminated on the radially inner side of the first cylindrical portion 34a1, and the end portion of the first cylindrical portion 34a1 on the first side in the axial direction is curled. Therefore, the second mandrel 34b is fixed to the first mandrel 34a

The lips 31 , 32 , and 33 are the first lip 31 , the second lip 32 , and the third lip 33 attached to the mandrel 34 , respectively. The first lip portion 31 and the third lip portion 33 are attached to the second circular portion 34b2 of the second mandrel 34b, and the second lip portion 32 is attached to the first circular portion 34a2 of the first mandrel 34a.

The second lip portion 32 extends from the first circular portion 34a2 to the first side in the axial direction. The side surface on the radially inner side of the second lip 32 is in contact with the second sealing surface 42 of the oil deflector 6 . A concave portion 32a is formed in the side surface on the radially outer side of the second lip portion 32, and an oil seal spring (second pressing member) 52 is provided in the concave portion 32a. The oil seal spring 52 is a coil spring formed in an annular shape, and is accommodated in the concave portion 32 a in the second lip portion 32 in a state where the oil seal spring 52 is elastically deformed in the extending direction. When the oil seal spring 52 elastically returns to the retracting direction, the second lip 32 is pressed toward the second sealing surface 42 .

The third lip portion 33 extends from the end portion on the radially inner side of the second circular portion 34b2 toward the first side in the axial direction. The side surface of the third lip portion 33 on the radially inner side is in contact with the third sealing surface 43 of the oil deflector 6 . The third sealing surface 43 is formed as an inclined surface (tapered surface) so that the outer diameter gradually becomes smaller from the first side toward the second side in the axial direction. The third lip 33 may be omitted. In this embodiment, the third sealing surface 43 is formed in a tapered shape. However, the third sealing surface 43 may have a cylindrical shape parallel to the axis direction.

The first lip portion 31 includes a base portion (first portion) 31a, a connection portion (second portion) 31b, and a contact portion (third portion) 31c. The base portion 31a extends from the first side surface on the first side in the axial direction of the second circular portion 34b2 to the same side. The connecting portion 31b extends radially outward from the extending end (the end on the first side in the axial direction) of the base portion 31a. The contact portion 31c extends from the extension end (radial outer end portion) of the connection portion 31b to the second side in the axial direction.

The side surface (outer peripheral surface) on the radially outer side of the contact portion 31c is referred to as the opposing surface 31c2 of the first sealing surface 41 facing the oil deflector 6, and at least a part of the opposing surface 31c2 is in contact with the first sealing surface 41. touch. Based on the first sealing surface 41 , the base portion 31 a is arranged on the opposite side of the contact portion 31 c from the first sealing surface 41 . Further, the connecting portion 31b connects the end portions of the base portion 31a and the contact portion 31c which are on the lubricating space side (first side in the axial direction) along the direction of the first sealing surface 41 .

The oil seal spring (first pressing member) 51 is accommodated in a space (accommodating space) S surrounded by the base portion 31a, the connecting portion 31b, and the contact portion 31c. Also, an opening A is provided between the base portion 31 a and the connection portion 31 c for the oil seal spring 51 to be inserted into the accommodating space S. As shown in FIG. The opening A is open on the second side in the axial direction. The oil seal spring 51 is a coil spring formed in an annular shape, and is accommodated in the accommodating space S in a state where the oil seal spring 51 is elastically deformed in the retracting direction. When the oil seal spring 51 elastically returns to the extending direction, the contact portion 31 c is pressed toward the first sealing surface 41 .

FIG. 5 is a cross-sectional view of the operation of the first lip portion 31 of the sealing member 7 . As shown by the solid line in FIG. 5 , the contact portion 31 c of the first lip portion 31 is inclined toward the radially outer side in a state where the contact portion 31 c is not in contact with the first sealing surface 41 of the oil deflector 6 . In this state, the width W1 of the opening A between the base portion 31a and the contact portion 31c is relatively large. Specifically, the radial position of the inner peripheral edge (side edge) 31 d (which is one edge of the opening A) of the distal end of the contact portion 31 c is the radial position of the radial position b of the radially outer end portion of the oil seal spring 51 . on the outside. Therefore, the oil seal spring 51 can be easily inserted into the accommodation space S via the opening A.

Meanwhile, as shown by the double-dotted chain line in FIG. 5 , in a state where the contact portion 31c is in contact with the first sealing surface 41, the contact portion 31c is elastically deformed radially inward, and the opening A is formed between the contact portion 31c and the contact portion 31c. The width W2 between the base portions 31a is reduced. The radial position a' of the inner peripheral edge 31d of the distal end of the contact portion 31c is on the radially inner side of the radial position b of the radially outer end portion of the oil seal spring 51 . Therefore, the oil seal spring 51 is not easily separated from the accommodating space S, whereby it can be ensured that the first lip 31 is brought into contact with the first sealing surface 41 . In particular, since the oil seal spring 51 is elastically deformed in the retracting direction, the oil seal spring 51 is easily deflected, and thus, the oil seal spring 51 is easily separated from the accommodating space S. However, since the width of the opening A is reduced, separation of the oil seal spring 51 can be surely avoided.

A raised portion 31c1 raised radially inward is formed in the inner peripheral edge 31d of the distal end of the contact portion 31c in the first lip portion 31 . Since the raised portion 31c1 is formed, when the contact portion 31c is brought into contact with the first sealing surface 41, the contact portion 31c easily deforms elastically radially inward, thereby reducing the width W2 of the opening A as much as possible.

As shown in FIG. 3 , in the sealing member 7 according to this embodiment, the first lip 31 is in contact with the first sealing surface 41 disposed toward the first radially inner side, and the second lip 32 and the third lip The portion 33 is in contact with the second sealing surface 42 and the third sealing surface 43, which are arranged toward the first radially outer side, respectively. Therefore, even when the shaft portion 4 is moved in the axial direction with respect to the bearing cap 11, the sealing performance is not deteriorated.

Also, when the shaft portion 4 moves radially relative to the bearing cap 11, on the first side in the radial direction of the shaft portion 4, the first lip portion 31 moves away from the first sealing surface 41, and the second lip portion 31 moves away from the first sealing surface 41. The portion 32 and the third lip portion 33 move towards the second sealing surface 42 and the third sealing surface 43, respectively. On the second side in the radial direction, the second lip 32 and the third lip 33 move away from the second sealing surface 42 and the third sealing surface 43 respectively, and the first lip 31 moves towards the first sealing surface 41 . Therefore, it is possible to ensure that the sealing effectiveness is almost uniform on both sides of the sealing member 7 in the radial direction.

In the slinger 6 , the second sealing surface 42 and the third sealing surface 43 are formed in the outer peripheral surface of the slinger body 6 a and arranged in the radial direction of the second sealing surface 42 and the third sealing surface 43 The first sealing surface 41 on the outer side is formed in the inner peripheral surface of the second extension portion 6c. Therefore, the second and third sealing surfaces 42, 43, and the first sealing surface 41 are arranged to face each other at an interval in the axial direction, and a space for arranging the sealing member 7 is formed on the second and third sealing surfaces 42 , 43 and the first sealing surface 41 . By inserting the sealing member 7 into the space, the lips 31, 32, 33 are brought into contact with the first sealing surface 41, the second sealing surface 42, and the third sealing surface 43, respectively, the first sealing surface 41, the second sealing surface The surface 42, and the third sealing surface 43 are arranged on both sides opposite to each other in the axial direction. Further, the first sealing surface 41 and the third sealing surface 43 are arranged at positions overlapping with respect to the axial direction. Therefore, the dimension of the sealing structure 1 in the axial direction is reduced as much as possible.

As described earlier, the sealing structure 1 according to this embodiment seals the inner space (lubrication space) of the roller bearing portion 5 lubricated by grease. Hereinafter, as shown in FIG. 3 , in the roller bearing portion 5 , the inner side of the first lip portion 31 with respect to the direction (axial direction) along the first seal surface 41 is referred to as the “lubrication space side” , the outer side of the first lip 31 is referred to as "the outer side of the lubrication space".

As shown in FIG. 5 , the contact portion 31c of the first lip portion 31 has a side surface (hereinafter, also referred to as “opposing surface”) 31c2 facing the first sealing surface 41, and a groove 61 is formed on the opposing surface 31c2 middle. The groove 61 extends in the axial direction from the end portion of the contact portion 31c on the lubrication space side to the side outside the lubrication space. Also, as shown in FIGS. 6A and 6B , the grooves 61 are provided at intervals in the circumferential direction of the first lip portion 31 at plural spaces. For example, the number of grooves 61 provided at equal intervals in the circumferential direction is sixteen. The cross section of the bottom surface of each of the grooves 61 according to this embodiment (a cross section taken in a direction orthogonal to this axis) has a circular arc shape.

Also, each of the grooves 61 includes a deep groove portion 61a on the lubricating space side, and a shallow groove portion 61b on the side outside the lubricating space. Bottom surfaces of the deep groove portion 61a and the shallow groove portion 61b are inclined with respect to the first sealing surface 41 so that the grooves 61 become deeper on the lubrication space side with respect to the axial direction. Also, the inclination of the bottom surface of the deep groove portion 61a is steeper than the inclination of the bottom surface of the shallow groove portion 61b. As shown in FIGS. 6A and 6B , the deep groove portion 61 a and the shallow groove portion 61 b have almost the same width W3 in the circumferential direction. Based on the above, each of the grooves 61 has a larger cross-sectional area on the lubricating space side than the cross-sectional area on the outer side of the lubricating space.

FIG. 7A shows the contact portion 31 c of the first lip portion 31 , which is in contact with the first sealing surface 41 . In this state, a portion of the opposing surface 31c2 of the contact portion 31c on the second side in the axial direction (the side outside the lubrication space) is in contact with the first sealing surface 41, and the opposing surface 31c2 of the opposing surface 31c2 is in contact with the first sealing surface 41 in the axial direction. A portion on the first side (lubricating space side) slightly rises from the first sealing surface 41 with a gap s.

FIG. 7B shows the first lip 31 when grease is supplied into the lubrication space. When the grease is supplied into the lubrication space, the supply pressure of the grease presses the first lip 31 in the direction shown by the arrow c. Therefore, a portion of the opposing surface 31 c 2 of the contact portion 31 c raised from the first sealing surface 41 is brought into contact with the first sealing surface 41 .

Then, as shown in FIG. 6B , the area of the opposing surface 31c2 of the contact portion 31c on the second side in the axial direction from the position L becomes the complete contact area R1 in which the entire circumference (entire surface) is in contact with the first sealing surface 41 to make contact. The position L is the position of the end of each of the grooves 61 on the second side in the axial direction (the side outside the lubrication space). Also, the area on the first side in the axial direction from the position L of the opposing surface 31c2, which is the position of the end of each of the grooves 61 on the second side in the axial direction, becomes a part Contact area R2. In the partial contact region R2, the opposing surface 31c2 not including the groove 61 is brought into contact with the first sealing surface 41 in the circumferential direction. Therefore, part of the contact region R2 is discontinuously (intermittently) in contact with the first sealing surface 41 . This means that the opposing surface 31c2 of the contact portion 31c includes a full contact region R1 and a partial contact region R2.

Therefore, as shown in FIG. 7B , even when the grease presses the first lip 31 in the direction indicated by the arrow c, the groove 61 in the partial contact region R2 does not come into contact with the first sealing surface 41 . Therefore, the grease in the lubricating space enters the groove 61, pushes the contact surface 31c with the supply pressure, and is discharged between the full contact area R1 of the contact portion 31c and the first sealing surface 41 (see arrow d). Therefore, it is possible to appropriately replace the old grease with the new grease in the lubricating space.

As shown in FIG. 6A , since the cross-sectional area of each of the grooves 61 on the lubrication space side is larger than the cross-sectional area on the side outside the lubrication space, grease easily flows into the grooves 61 . Therefore, it is possible to further improve the discharge performance of the grease when the grease is supplied.

As shown in FIG. 7B , in the opposing surface 31c2 of the contact portion 31c, the boundary L between the full contact region R1 and the partial contact region R2 is positioned in the range D1 which is in the axial direction of the oil seal spring 51 Between the end portion 51b on the first side (lubricating space side) of the oil seal spring 51 and the center 51a of the oil seal spring 51 in the axial direction. When the boundary L is positioned on the first side in the axial direction of the end portion 51b, it becomes difficult for the grease to enter the groove 61 to push up the full contact area R1 of the opposing surface 31c2. When the boundary L is positioned on the second side in the axial direction (side outside the lubrication space) from the center 51a, the sealing effectiveness of the contact portion 31c deteriorates with respect to the surface pressure in the full contact surface R1.

8A and 8B show changes in the surface pressure of the full contact region R1 on the first sealing surface 41 when the grease supply pressure is applied to the first lip 31 . As shown in FIG. 8A, when the boundary L between the full contact region R1 and the partial contact region R2 coincides with the center 51a of the oil seal spring 51, the surface pressure of the full contact region R1 on the first sealing surface 41 is in the full contact region The end of R1 on the lubrication space side becomes a peak (reference point P1). Therefore, water and the like can easily enter the outer side of the self-lubricating space.

As shown in FIG. 8B, when the boundary L is on the lubrication space side from the center 51a of the oil seal spring 51, the surface pressure of the full contact region R1 on the first sealing surface 41 is outside the lubrication space of the full contact region R1 becomes a peak at the end on the side of , (reference point P2). Therefore, it is possible to properly prevent the entry of water from the side outside the lubricating space, whereby the sealing performance is properly maintained.

FIGS. 9A and 9B are views corresponding to FIGS. 6A and 6B , respectively, and show modifications of the grooves 61 of the first lip 31 . Each of the grooves 61 according to this modification is provided such that the width W4 in the circumferential direction of the deep groove portion 61a is larger than the width W3 in the circumferential direction of the shallow groove portion 61b. The cross-sectional shape of the deep groove portion 61a is an arc shape. According to this modification, it is possible to increase the cross-sectional shape of the deep groove portion 61 a, and it is possible to facilitate the inflow of grease into the groove 61 . Second Embodiment

10 is an enlarged cross-sectional view of the first lip of the sealing structure according to the second embodiment. In this embodiment, instead of the grooves 61, a plurality of protrusions 62 are provided at intervals in the circumferential direction in the opposing surfaces 31c2 of the contact portion 31c. The protruding portion 62 is arranged in a range D2 that is farther on the first side in the axial direction from the end portion 51b of the oil seal spring 51 on the first side (lubricating space side) in the axial direction.

By providing the protrusion 62, when grease is supplied into the lubricating space, the grease supply pressure does not allow the opposing surface 31c2 to come into full contact with the first sealing surface 41, and there is always a gap between the opposing surface 31c2 and the first sealing surface 41. There are gaps. Therefore, the grease enters the gap s, and the grease entering the gap s pushes up the full contact region R1 of the contact portion 31c, thereby discharging the grease.

Since the protruding portion 62 is formed in the range D2, it can be ensured that the end portion of the contact portion 31c on the lubricating space side is raised from the first sealing surface 41, so that the gap s is formed. Therefore, grease can enter the gap s.

The present invention is not limited to these embodiments, and changes may be made without departing from the scope of the invention as described in the claims. For example, the number of grooves 61 and protrusions 62 provided in the contact portion 31 c of the first lip portion 31 , the lengths of the grooves 61 and the protrusions 62 in the axial direction, the distance between the grooves 61 and the protrusions 62 The width in the circumferential direction, the cross-sectional shapes of the grooves 61 and the protrusions 62, and the like can be appropriately changed.

The sealing member 7 may not be in contact with the oil deflector 6 and may be in direct contact with the shaft portion 4 . Furthermore, the sealing member 7 may be constructed so as to be fixed on the side of the shaft portion 4 and to come into contact with the side of the bearing cap 11 . The sealing structure 1 according to the present invention can be applied to a sealing structure other than the sealing structure between the shaft portion 4 of the cross joint 20 and the bearing cap 11 .

2‧‧‧Joint cross piece 3‧‧‧Base part 3a‧‧‧Grease hole 4‧‧‧Shaft part 5‧‧‧Roller bearing part 6‧‧‧Oil retaining ring 6a‧‧‧Oil retaining ring body 6b ‧‧‧First extension part 6c‧‧‧Second extension part 6d‧‧‧Third extension part 7‧‧‧Sealing member 8‧‧‧Roller guide 9‧‧‧Needle roller 10‧‧‧Spacer 11 ‧‧‧Bearing cap 11a‧‧‧Grease hole 13‧‧‧Grease channel 17‧‧‧Yoke 20‧‧‧Cross joint 31‧‧‧First lip 31a‧‧‧Seat part 31b‧‧‧Connecting part 31c‧ ‧‧contact part 31c1‧‧‧raised part 31c2‧‧‧counter surface 31d‧‧‧inner peripheral edge 32‧‧‧second lip part 32a‧‧‧recessed part 33‧‧‧third lip part 34‧‧‧core Rod 34a‧‧‧First mandrel 34a1‧‧‧First cylindrical part 34a2‧‧‧First circular part 34b‧‧‧Second mandrel 34b1‧‧‧Second cylindrical part 34b2‧‧‧Second Circular part 41‧‧‧First sealing surface 42‧‧‧Second sealing surface 43‧‧‧Third sealing surface 51‧‧‧Oil seal spring 51a‧‧‧Center 51b‧‧‧End 52‧‧‧Oil seal spring 61‧‧‧Groove 61a‧‧‧Deep groove part 61b‧‧‧Shallow groove part 62‧‧‧Protruding part 106‧‧‧Oil retaining ring 107‧‧‧Sealing member 111‧‧‧Bearing cap 131‧‧ ‧Lip 131c2‧‧‧Side surface 134‧‧‧Mandrel 141‧‧‧Sealing surface 151‧‧‧Oil seal spring A‧‧‧Opening a‧‧‧Radial position a'‧‧‧Radial position b‧‧ ‧Radial position C‧‧‧Center axis c‧‧‧Arrow number d‧‧‧Arrow number D1‧‧‧Range D2‧‧‧Range E‧‧‧Arrow number F‧‧‧Arrow number L‧‧‧Location, Boundary P1‧‧‧Point P2‧‧‧Point S‧‧‧Accommodating space s‧‧‧Gap W1‧‧‧Width W2‧‧‧Width W3‧‧‧Width W4‧‧‧Width X‧‧‧Axis Y‧‧ ‧Axis Z‧‧‧Axis

The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals designate like elements, and wherein: FIG. 1 is an application according to a first embodiment Fig. 2 is a side view (partial sectional view) of the cross joint of the sealing structure; Fig. 3 is a sectional view of the sealing structure; Fig. 4 is a sectional view of the sealing member of the sealing structure; Figure 6A is a view in the direction of arrow E in Figure 5; Figure 6B is a view in the direction of arrow F in Figure 5; Figure 7A is a first A cross-sectional view of the lip, wherein grease supply pressure is not applied to the first lip; Figure 7B is a cross-sectional view of the first lip, wherein grease supply pressure is applied to the first lip; Figure 8B is a view depicting changes in surface pressure on a full contact region of a sealing structure with a first sealing surface; Figure 9A is a first lip Fig. 9B is a modified view of the groove in the first lip, corresponding to Fig. 6B; Fig. 10 is a view of the sealing structure according to the second embodiment An enlarged cross-sectional view of the first lip; FIG. 11 is a cross-sectional view of the lip of the sealing structure according to the related art; and FIG. 12 is a cross-sectional view of the lip of the sealing structure according to the related art, wherein grease supply pressure is applied to the lip department.

31‧‧‧First lip

31a‧‧‧Pedestal

31b‧‧‧Connecting part

31c‧‧‧contact part

31c2‧‧‧Opposite surfaces

41‧‧‧First sealing surface

51‧‧‧Oil seal spring

61‧‧‧Grooving

61a‧‧‧Deep groove

61b‧‧‧Shallow groove

s‧‧‧clearance

Claims (7)

A sealing structure (1) comprising: a first member (11); a second member (6) arranged coaxially with the first member (11) and arranged to rotate relative to the first member (11) , the second member (6) faces the first member (11) in the radial direction; and the sealing member (7), which has an annular shape and is mounted on the first member (11) and is arranged on the first member (11) The sealing surface (41) in the second member (6) is in sliding contact, wherein the first member (11) and the second member (6) define a lubricating space filled with grease, the sealing member (7) comprising a lip (31) and a pressing member (51), the lip (31) including an opposing surface (31c2) facing the sealing surface (41), the pressing member (51) pressing the opposing surface (31c2) to the sealing surface ( 41), the lip (31) includes: a contact portion (31c) including the opposing surface (31c2); a base portion (31a) positioned on the contact portion (31c) with the sealing surface (41) on the opposite side; and a connecting portion (31b) which connects the end portion of the contact portion (31c) on the lubrication space side in the direction along the sealing surface (41) with the seat portion (31a) ) connection, the pressing member (51) is arranged in the space surrounded by the contact portion (31c), the base portion (31a) and the connecting portion (31b), The opposing surface (31c2) includes a complete contact area (R1) and a partial contact area (R2), the complete contact area (R1) being constructed on the outside of the lubricating space along the direction of the sealing surface (41) The side is in contact with the sealing surface (41) over the entire circumference, and the part of the contact area (R2) is constructed to be in contact with the lubrication in the direction along the sealing surface (41) when the grease is supplied to the lubrication space The space side is in discontinuous contact with the sealing surface (41) in the circumferential direction, and the full contact area (R1) is pushed up by the supply pressure of the grease when the grease is supplied to the lubricating space. The sealing structure (1) as claimed in claim 1, wherein the boundary between the full contact area (R1) and the partial contact area (R2) is positioned at a distance from the end of the pressing member (51) On the side of the outside of the lubricating space, the end of the pressing member (51) is positioned on the lubricating space side in the direction along the sealing surface (41). The sealing structure (1) according to claim 2, wherein the boundary is arranged on the lubricating space side in the direction along the sealing surface (41) from the center of the pressing member (51). The sealing structure (1) according to any one of claims 1 to 3, wherein a groove (61) is provided in the part of the contact area (R2) of the opposing surface (31c2), the groove (61) extends from the lubricating space side to the side of the outer portion of the lubricating space in the direction along the sealing surface (41). The sealing structure (1) as claimed in claim 4, wherein the cross-sectional area of the groove (61) is larger on the lubricating space side along the direction of the sealing surface (41). The sealing structure (1) according to any one of claims 1 to 3, wherein a plurality of protrusions (62) are in the circumferential direction in the partial contact area (R2) of the opposing surface (31c2) is set with spacing. The sealing structure (1) according to claim 6, wherein the protrusions (62) are arranged on the lubricating space side from the end of the pressing member (51), the pressing member (51) The end of the is positioned on the lubricating space side in the direction along the sealing surface (41).

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