TW201918643A - 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 is directed to a sealing structure that is disposed between two members that rotate relative to each other. These two members are, for example, a shaft portion and a bearing cup of a cruciform joint.

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

The inventors of the present application have 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 that is mounted on the bearing cap 111 and in sliding contact with a slinger 106. The oil slinger 106 has a sealing surface 141 that faces radially inward. The sealing member 107 includes a core bar 134 fixed to the bearing cap 111, a lip 131 adhered to the mandrel 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 the grease is used to lubricate the space between the oil retaining ring 106 and the bearing cap 111 (lubrication space), in order to replace the grease in the lubrication space with new grease during maintenance, etc., it is necessary to supply the new grease from the grease hole. The old grease is discharged from the lip 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 top sealing surface 141, as indicated by an arrow c in FIG. And the side surface 131c2 of the lip 131 facing the sealing surface 141 is in strong contact with almost the entire sealing surface 141. Therefore, it is difficult to discharge the grease to the outside 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 for improving the effectiveness of discharging old grease when a new grease is supplied to a sealing structure sealed with a grease-filled sealed space.

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 disposed coaxially with the first member and is configured to rotate relative to the first member. The second member faces the first member in a radial direction. The sealing member has an annular shape and is mounted on the first member and in sliding contact with the sealing surface provided in the second member. The first member and the second member define a lubrication space filled with grease. The sealing member includes a lip portion and a pressing member. The lip includes: a contact portion including a facing surface facing the sealing surface; a base portion positioned on a side of the contact portion opposite to the sealing surface; and a connecting portion that is along the contact portion The direction of the sealing surface is connected to the base portion at the end on the lubrication space side. The pressing member is disposed inside the space surrounded by the contact portion, the base portion, and the connecting portion. The pressing member presses the opposite surface to the side of the sealing surface. The opposing surface includes a full contact area and a partial contact area. The full contact zone is constructed to contact the sealing surface over the entire circumference on the side of the outer side of the lubrication space in the direction along the sealing surface when the grease is supplied to the lubrication space. The partial contact zone is constructed to be in discontinuous contact with the sealing surface in the circumferential direction on the lubrication space side in the direction along the sealing surface.

With this configuration, even when the lip is pressed against the top sealing surface by the grease supplied to the lubrication space, since the partial contact portion of the opposite surface has a portion that is not in contact with the sealing surface, the grease self-lubricating space side Enter this section and the grease pushes up the full contact area and is discharged outside the lubrication space. Therefore, it is possible to improve the efficiency of discharging old grease when new grease is supplied. In addition, it is possible to ensure sufficient sealing performance due to the complete contact area on the opposite surface.

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

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

In the sealing structure, the groove may be disposed in a partial contact area of the opposite surface, the groove extending from the lubrication space side to the outside of the lubrication space in the direction along the sealing surface. With this configuration, when grease is supplied to the lubrication space, the old grease in the lubrication space enters the groove, pushes up the full contact area, and is discharged to the outside of the lubrication space.

In the sealing structure, the cross-sectional area of the groove may be larger on the side of the lubrication space 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, a plurality of protrusions may be disposed at a pitch in a circumferential direction in a partial contact area of the opposing surface. By providing the protrusion, a gap is formed between the opposite surface of the contact portion and the sealing surface, and when the grease is supplied, the grease is allowed to enter the gap, the full contact area is pushed up, and discharged.

In the sealing structure, the protrusion may be configured to be on the lubrication space side from the end of the pressing member, the end being positioned on the lubrication space side in the direction along the sealing surface. With this configuration, it is ensured that the end portion of the contact portion on the lubrication space side is raised from the sealing surface, and the gap is thus formed. The grease is then allowed to enter the gap.

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

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

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

The joint cross member 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 axis X and the axis Z orthogonal to each other. The joint cross member 2 is rotatable about 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 member 2, the grease passage 13 is provided to have a cross shape along the axis X and the axis Z. The grease passage 13 is used to supply the lubricant into the roller bearing portion 5.

As shown in FIG. 2, the grease holes 3a, 11a are respectively provided in the side surface of the base portion 3 of the joint cross member 2, and the bearing cover 11 (described later) of the roller bearing portion 5. The grease holes 3a, 11a are connected to the grease passage 13. The lubricant is supplied to the roller bearing portion 5 via the grease holes 3a, 11a and the grease passage 13. In this embodiment, grease is used as a lubricant. Further, the grease may be continuously supplied while the device having the cross joint 20 is operating, or the grease may be periodically supplied (for example, every three 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 roller 9 is disposed along the outer peripheral surface of each of the shaft portions 4 so that the needle roller 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 roller 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 race. Therefore, the bearing cap 11 can swing about the axis Z of the shaft portion 4.

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

3 is a cross-sectional view of the sealing structure 1. 4 is a cross-sectional view of the sealing member 7 in a state where the sealing member 7 is not in contact with the oil slinger 6 (in other words, in a state where the sealing member 7 is in a natural state). The sealing structure 1 is provided to prevent water or the like from entering the lubrication space, and also prevents the lubricant from leaking to the outside from the lubrication space. The lubrication space is a space in which the needle roller 9 is disposed between the shaft portion 4 and the bearing cap 11 and the grease is also filled. 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 represent absolute exact directions with respect to the axial direction, but rather they represent relative directions. Therefore, the first side and the second side can be replaced with each other. The same applies to the "first side in the radial direction" and the "second side in the radial direction".

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

On the outer peripheral surface of the slinger body 6a, the second sealing surface 42 and the third sealing surface 43 are formed side by side in the axial direction. Further, on the inner peripheral surface of the second extending portion 6c, the 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 slinger 6, the third extension portion 6d is provided. The third extension 6d extends further radially outward from the second extension 6c. The outer peripheral surface of the second extending portion 6c and the side surface of the third extending portion 6d on the second side in the axial direction face the end of the bearing cover 11 via the gap. The gap serves to prevent water or the like from entering the seal gap between the oil retaining ring 6 and the bearing cap 11.

The sealing member 7 includes a core rod (fixing portion) 34 and lips 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 core rod 34 has a first cylindrical portion 34a1 and a first circular portion 34a2 that is bent radially inward from an end portion of the first cylindrical portion 34a1 on the second side in the axial direction. The second core rod 34b has a second cylindrical portion 34b1 and a second circular portion 34b2 that is 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 core rod 34b is fixed to the first core rod 34a

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

The second lip 32 extends from the first circular portion 34a2 to the first side in the axial direction. The side surface of the second lip portion 32 on the radially inner side is in contact with the second sealing surface 42 of the oil slinger 6. The concave portion 32a is formed in a side surface on the radially outer side of the second lip portion 32, and an oil seal spring (second pressing member) 52 is disposed in the concave portion 32a. The oil seal spring 52 is a coil spring formed into an annular shape, and is accommodated in the concave portion 32a 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 on the radially inner side of the third lip portion 33 is in contact with the third sealing surface 43 of the oil slinger 6. The third sealing surface 43 is formed as an inclined surface (tapered surface) such that the outer diameter gradually becomes smaller from the first side in the axial direction toward the second side. The third lip 33 can be omitted. In this embodiment, the third sealing surface 43 is formed into a tapered shape. However, the third sealing surface 43 may have a cylindrical shape parallel to the axial direction.

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

The side surface (outer peripheral surface) of the contact portion 31c on the radially outer side is referred to as the opposite surface 31c2 facing the first sealing surface 41 of the oil slinger 6, and at least a portion of the opposing surface 31c2 is made with the first sealing surface 41 contact. Based on the first sealing surface 41, the base portion 31a is disposed on the side of the contact portion 31c opposite to 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 lubrication space side (the first side in the axial direction) along the direction of the first sealing surface 41.

The oil seal spring (first pressing member) 51 is housed in a space (accommodation space) S surrounded by the base portion 31a, the connecting portion 31b, and the contact portion 31c. Further, the opening A is provided between the base portion 31a and the connecting portion 31c so that the oil seal spring 51 is inserted into the accommodating space S. 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 housed in the accommodation 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 31c is pressed toward the first sealing surface 41.

FIG. 5 is a cross-sectional view showing the actuation of the first lip portion 31 of the sealing member 7. As shown by the solid line in FIG. 5, the contact portion 31c of the first lip portion 31 is inclined outward in the radial direction in a state where the contact portion 31c is not in contact with the first sealing surface 41 of the oil slinger 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) 31d of the distal end of the contact portion 31c, which is an edge of the opening A, is the radial direction at 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-dot 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 contact portion 31c of the opening A and 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 accommodation space S, whereby the first lip portion 31 can be ensured to be brought into contact with the first seal 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 therefore, the oil seal spring 51 is easily separated from the accommodation space S. However, since the width of the opening A is reduced, it is ensured that the oil seal spring 51 is prevented from being separated.

A bulge 31c1 that is radially inwardly raised 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 ridge portion 31c1 is formed, when the contact portion 31c is caused to come into contact with the first sealing surface 41, the contact portion 31c is easily elastically deformed radially inward, whereby the width W2 of the opening A is reduced as much as possible.

As shown in FIG. 3, in the sealing member 7 according to this embodiment, the first lip portion 31 is in contact with the first sealing surface 41 disposed toward the first radially inner side, and the second lip portion 32 and the third lip portion The portions 33 are in contact with the second sealing surface 42 and the third sealing surface 43 which are disposed 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.

Further, when the shaft portion 4 moves radially with respect to the bearing cover 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 The portion 32 and the third lip portion 33 move toward 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 toward the first sealing surface 41. Therefore, it is possible to ensure that the sealing performance is almost evenly on both sides of the sealing member 7 in the radial direction.

In the oil slinger 6, the second sealing surface 42 and the third sealing surface 43 are formed in the outer peripheral surface of the slinger body 6a, and are disposed 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 disposed to face each other at a pitch in the axial direction, and a space for arranging the sealing member 7 is formed at the second and third sealing surfaces 42, 43 is between the first sealing surface 41. By inserting the sealing member 7 into the space, the lips 31, 32, 33 are respectively brought into contact with the first sealing surface 41, the second sealing surface 42, and the third sealing surface 43, the first sealing surface 41, the second sealing The surface 42 and the third sealing surface 43 are disposed on both sides of the axial direction opposite to each other. Further, the first sealing surface 41 and the third sealing surface 43 are disposed 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 sealing surface 41 is referred to as "lubrication space side". The outer side of the first lip portion 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 the groove 61 is formed on the opposite surface 31c2. in. The groove 61 extends from the end of the contact portion 31c on the lubrication space side in the axial direction to the side of the outer portion of the lubrication space. Further, 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 a plurality of spaces. For example, the number of the grooves 61 provided at equal intervals in the circumferential direction is 16. The section of the bottom surface of each of the grooves 61 according to this embodiment (the section taken along the direction orthogonal to this axis) has a circular arc shape.

Also, each of the grooves 61 includes a deep groove portion 61a on the lubrication space side, and a shallow groove portion 61b on the outer side of the lubrication space. The bottom surface of the deep groove portion 61a and the shallow groove portion 61b is inclined with respect to the first sealing surface 41, so that the groove 61 becomes deeper on the lubrication space side with respect to the axial direction. Further, 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 61a and the shallow groove portion 61b have almost the same width W3 in the circumferential direction. Based on the above, each of the grooves 61 has a cross-sectional area on the lubrication space side that is larger than the cross-sectional area on the outer side of the lubrication space.

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

Fig. 7B shows the first lip portion 31 when the 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 portion 31 in the direction indicated by the arrow c. Therefore, a portion of the opposing surface 31c2 of the contact portion 31c that is raised by the first sealing surface 41 comes into contact with the first sealing surface 41.

Then, as shown in FIG. 6B, the region of the opposite surface 31c2 of the contact portion 31c from the position L on the second side in the axial direction becomes the full contact region R1, wherein the entire circumference (entire surface) and the first sealing surface 41 contact. The position L is the position of the end on the second side (the side on the outer side of the lubrication space) of each of the grooves 61 in the axial direction. Further, the area on the first side in the axial direction from the position L of the opposite surface 31c2 which is the position of the end on the second side in the axial direction of each of the grooves 61 becomes a part Contact zone R2. In the partial contact region R2, the opposite surface 31c2 not including the groove 61 comes into contact with the first sealing surface 41 in the circumferential direction. Therefore, the partial contact region R2 is in discontinuous (intermittent) contact with the first sealing surface 41. This means that the opposite surface 31c2 of the contact portion 31c includes the full contact region R1 and the partial contact region R2.

Therefore, as shown in FIG. 7B, even when the grease presses the first lip portion 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 lubrication space enters the groove 61, the contact surface 31c is pushed by the supply pressure, and is discharged between the full contact region R1 of the contact portion 31c and the first sealing surface 41 (refer to the arrow d). Therefore, it is possible to appropriately replace the old grease with the new grease in the lubrication space.

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

As shown in FIG. 7B, in the opposite 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, and the range D1 is in the axial direction of the oil seal spring 51. The end portion 51b on the first side (lubrication space side) 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, the grease becomes difficult to enter the groove 61 to push up the full contact region R1 of the opposite surface 31c2. When the boundary L is positioned from the second side (the outer side of the lubrication space) of the center 51a in the axial direction, the sealing performance of the contact portion 31c deteriorates in relation 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 portion 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 complete contact region. The end of R1 becomes a peak at the end on the lubrication space side (reference point P1). Therefore, the outer side of the self-lubricating space such as water easily enters.

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. The end on the side of the side becomes a peak (point P2). Therefore, it is possible to suitably avoid the side entry of the water from the outside of the lubrication space, whereby the sealing performance is suitably maintained.

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

Figure 10 is an enlarged cross-sectional view of a first lip of a sealing structure in accordance with a second embodiment. In this embodiment, instead of the groove 61, a plurality of projections 62 are provided at intervals in the circumferential direction in the opposing surface 31c2 of the contact portion 31c. The projection 62 is disposed in the range D2 which is farther from the end portion 51b on the first side (lubrication space side) of the oil seal spring 51 in the axial direction on the first side in the axial direction.

By providing the protrusion 62, when the grease is supplied into the lubrication space, the grease supply pressure does not allow the opposite surface 31c2 to completely contact the first sealing surface 41, and always between the opposite surface 31c2 and the first sealing surface 41 There is a gap s. 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 is 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, the grease can enter the gap s.

The invention is not limited to the embodiments, and may be modified without departing from the scope of the invention as described in the appended claims. For example, the number of the grooves 61 and the projections 62 provided in the contact portion 31c of the first lip portion 31, the length of the groove 61 and the projection portion 62 in the axial direction, the groove 61, and the projection 62 are The width in the circumferential direction, the cross-sectional shape of the groove 61 and the projection 62, and the like can be appropriately changed.

The sealing member 7 may not be in contact with the oil slinger 6 and may be in direct contact with the shaft portion 4. Further, the sealing member 7 can be constructed to be fixed to the side of the shaft portion 4 and to be in contact with the side of the bearing cover 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 cover 11.

2‧‧‧Connector cross

3‧‧‧Base section

3a‧‧‧ grease hole

4‧‧‧ shaft section

5‧‧‧Roller Bearings

6‧‧‧ oil retaining ring

6a‧‧‧Oil ring body

6b‧‧‧First Extension

6c‧‧‧Second extension

6d‧‧‧ third extension

7‧‧‧ Sealing member

8‧‧‧Roller Guides

9‧‧‧needle needle

10‧‧‧shims

11‧‧‧ bearing cap

11a‧‧‧ grease hole

13‧‧‧ Grease channel

17‧‧‧ yoke

20‧‧‧cross joint

31‧‧‧First lip

31a‧‧‧Base section

31b‧‧‧Connecting Department

31c‧‧‧Contacts

31c1‧‧‧ Uplift

31c2‧‧‧ opposite surface

31d‧‧‧ inner peripheral edge

32‧‧‧Second lip

32a‧‧‧ recessed part

33‧‧‧ Third lip

34‧‧‧ mandrel

34a‧‧‧First mandrel

34a1‧‧‧First cylindrical part

34a2‧‧‧ first round

34b‧‧‧Second mandrel

34b1‧‧‧Second cylindrical part

34b2‧‧‧Second round

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

61b‧‧‧ shallow groove

62‧‧‧Protruding

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‧‧‧ openings

A‧‧‧ radial position

A’‧‧‧ radial position

B‧‧‧ radial position

C‧‧‧ center axis

C‧‧‧arrow

D‧‧‧arrow

D1‧‧‧Scope

D2‧‧‧Scope

E‧‧‧ arrows

F‧‧‧Arrow

L‧‧‧Location, border

P1‧‧ points

P2‧‧ points

S‧‧‧ accommodation space

S‧‧‧ gap

W1‧‧‧Width

W2‧‧‧Width

W3‧‧‧Width

W4‧‧‧Width

X‧‧‧ axis

Y‧‧‧ axis

Z‧‧‧ axis

Features, advantages, and technical and industrial saliency of the exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which Figure 2 is a side view (partial cross-sectional view) of the cross joint; Figure 3 is a cross-sectional view of the sealing structure; Figure 4 is a cross-sectional view of the sealing member of the sealing structure; Figure 5 is a view Figure 6A is a view in the direction of arrow F in Figure 5; Figure 6B is a view in the direction of arrow F in Figure 5; Figure 7A is the first view; a cross-sectional view of the lip in which the grease supply pressure is not applied to the first lip; FIG. 7B is a cross-sectional view of the first lip in which the grease supply pressure is applied to the first lip; FIG. 8A is depicted in the first View of the change in surface pressure on the complete contact area of the sealing structure of the sealing surface; Figure 8B is a complete depiction of the sealing structure with the first sealing surface View of the change in surface pressure on the contact zone; FIG. 9A is a modified view of the groove in the first lip, which corresponds to FIG. 6A; FIG. 9B is a modified view of the groove in the first lip, Corresponding to FIG. 6B; FIG. 10 is an enlarged cross-sectional view of the first lip of the sealing structure according to the second embodiment; FIG. 11 is a cross-sectional view of the lip of the sealing structure according to the related art; and FIG. A cross-sectional view of the lip of the sealing structure in which grease supply pressure is applied to the lip.

Claims (7)

A sealing structure (1) comprising: a first member (11); a second member (6) disposed coaxially with the first member (11) and arranged to rotate relative to the first member (11) a second member (6) facing the first member (11) in a radial direction; and a sealing member (7) having an annular shape and mounted on the first member (11) and disposed thereon 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 lubrication space filled with grease, the sealing member (7) including a lip (31) and a pressing member (51), the lip portion (31) comprising: a contact portion (31c) including an opposite surface (31c2) facing the sealing surface (41); a base portion (31a) positioned at a side of the contact portion (31c) opposite to the sealing surface (41); and a connecting portion (31b) that faces the lubricating portion side of the contact portion (31c) in a direction along the sealing surface (41) The upper end is connected to the base portion (31a), and the pressing member (51) is disposed by the contact portion (31c), Inside the space surrounded by the base portion (31a) and the connecting portion (31b), the pressing member (51) presses the opposite surface (31c2) to the side of the sealing surface (41), and the opposite surface (31c2) includes a full contact zone (R1) and a partial contact zone (R2), the complete contact zone (R1) being constructed in the lubricating space along the direction of the sealing surface (41) when the grease is supplied to the lubrication space The outer side is in contact with the sealing surface (41) over the entire circumference, and the partial contact area (R2) is constructed in the circumferential direction along the lubricating space side in the direction along the sealing surface (41) The sealing surface (41) is in discontinuous contact. The sealing structure (1) of claim 1, wherein a boundary between the full contact region (R1) and the partial contact region (R2) is positioned from an end of the pressing member (51) On the outer side of the lubrication 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) of claim 2, wherein the boundary is disposed from the center of the pressing member (51) on the lubricating space side in the direction along the sealing surface (41). The sealing structure (1) according to any one of claims 1 to 3, wherein a groove (61) is provided in the partial contact region (R2) of the opposite surface (31c2), the groove (61) extending from the lubrication space side to the side of the outer portion of the lubrication space in the direction along the sealing surface (41). The sealing structure (1) of claim 4, wherein the cross-sectional area of the groove (61) is larger on the lubricating space side in the direction along 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 opposite surface (31c2) Set with spacing. The sealing structure (1) according to claim 6, wherein the protrusions (62) are disposed from the end of the pressing member (51) on the lubrication space side, the pressing member (51) The end portion is positioned on the lubrication space side in the direction along the sealing surface (41).