JP2019086105A - Seal structure - Google Patents

Abstract

To enhance discharge performance of old grease when supplying new grease, in a seal structure for sealing a lubrication space in which grease is filled.SOLUTION: A seal member 7 of a seal structure 1 includes: a lip part 31 having an opposing surface 31c2 opposing to a seal surface 41; and a pressing member 51 for pressing the opposing surface 31c2 to the seal surface 41 side. The lip part 31 includes: a contact part 31c; a base part 31a positioned on the opposite side from the seal surface 41 by sandwiching the contact part 31c; and a connection part 31b for connecting the contact part 31c and the base part 31a at an end part on the lubrication space side in the direction along the seal surface 41. The pressing member 51 is arranged in a space surrounded by the contact part 31c, the base part 31a, and the connection part 31b. The opposing surface 31c2 comprises: a whole contact region R1 which comes into contact with the seal surface 41 with the whole circumference on the outside part side of the lubrication space in the direction along the seal surface 41; and a partial contact region R2 which comes into discontinuous contact with the seal surface 41 in the circumferential direction on the lubrication space side in the direction along the seal surface 41.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a sealing structure provided between two members which rotate relative to each other, such as a shaft and a bearing cup in a cruciform joint, for example.

  For example, in a spindle device of a steel rolling mill or a drive shaft of a car, a cruciform joint is used as a universal joint at a connecting portion between shafts. This cross joint has a cross shaft in which four shaft portions are arranged in a cross shape, a cylindrical bearing cup with a bottom, which is placed on each shaft portion, an outer peripheral surface of each shaft portion and an inner peripheral surface of the bearing cup And a plurality of needle rollers rotatably disposed between the two, and a yoke provided at an end of each shaft is connected to the bearing cup. In addition, in order to prevent the entry of water and the like into the accommodation space of the needle roller formed between the axial part and the bearing cup, and to suppress the leakage of the lubricant from the accommodation space to the outside, the base of the axial part A sealing structure is provided between the end and the end of the bearing cup (see, for example, Patent Document 1).

European Patent Publication No. 1783384

  The inventor of the present application has previously proposed a sealing structure shown in FIG. 11 (Japanese Patent Application No. 2016-217292 (unpublished)). The sealing structure includes an annular seal member 107 attached to the bearing cup 111 and in sliding contact with the slinger 106, the slinger 106 having a radially inwardly facing seal surface 141, and the seal member 7 on the bearing cup 111. A core metal 134 to be fixed, a lip portion 131 adhered to the core metal 134 and in contact with the seal surface 141, and a garter spring 151 for pressing the lip portion 131 toward the seal surface 41 are provided.

  When lubricating the space (lubricated space) between the slinger 106 and the bearing cup 111 with grease, to replace the grease in the lubricated space with new grease at the time of maintenance, etc., supply new grease from the oil supply hole Along with this, it is necessary to discharge the old grease from the lip portion 131 to the outside. However, in the case of the sealing structure shown in FIG. 11, when fresh grease is supplied to the lubrication space, a force pressing lip portion 131 against sealing surface 141 acts as shown by arrow c in FIG. The substantially entire side surface 131 c 2 of the lip portion 131 strongly contacts the sealing surface 141. Therefore, it has been difficult to discharge the grease to the outside of the lubrication space through between the lip portion 131 and the seal surface 141.

  An object of the present invention is to enhance the discharge performance of old grease when supplying new grease in a sealing structure for sealing a lubrication space filled with grease.

  (1) The present invention includes a first member, a second member disposed concentrically with the first member to face the first member in the radial direction, and rotating relative to the first member, and the first member An annular seal member attached to and in sliding contact with a seal surface formed on the second member, and sealing a lubricating space filled with grease between the first member and the second member A sealing structure, wherein the sealing member includes a lip having an opposing surface facing the sealing surface, and a pressing member for pressing the opposing surface toward the sealing surface, the lip being the opposing surface A contact portion having the contact portion, a base opposite to the sealing surface across the contact portion, and an end of the contact portion on the lubricating space side in a direction along the sealing surface to the base A connecting portion, and the pressing member is The sealing surface is disposed in a space surrounded by the contact portion, the base portion, and the connection portion, and the opposing surface is the sealing surface on the outer side of the lubricating space in the direction along the sealing surface when supplying grease to the lubricating space. It has a full contact area in contact with the entire circumference, and a partial contact area in discontinuous contact with the seal surface in the circumferential direction on the side of the lubricating space in the direction along the seal surface.

  According to the above configuration, even if the lip portion is pressed against the seal surface by the grease supplied into the lubricating space, there is a portion not in contact with the seal surface in the partial contact region of the opposing surface. Grease enters from the lubrication space side, and the grease pushes up the entire contact area and is discharged to the outside of the lubrication space. Therefore, the discharge performance of old grease when supplying new grease can be enhanced. In addition, since the facing surface is provided with the entire contact area, the sealability by the first portion can be sufficiently secured.

(2) Preferably, the boundary between the entire contact area and the partial contact area is disposed on the outer side of the lubricating space than the end of the pressing member located on the lubricating space side in the direction along the seal surface It is done.
Such a configuration can improve the grease discharge performance.

(3) Preferably, the boundary is disposed closer to the lubricating space than the center of the pressing member in the direction along the seal surface.
With such a configuration, the grease discharging performance can be enhanced while securing the sealing performance in the entire contact area.

(4) Preferably, in the partial contact area of the opposing surface, a groove extending from the lubricating space side to the outer side of the lubricating space in the direction along the seal surface is formed.
According to this configuration, when the grease is supplied into the lubrication space, the old grease in the lubrication space gets into the groove, pushes up the entire contact area, and is discharged to the outside of the lubrication space.

(5) Preferably, the cross-sectional area of the groove is larger toward the lubricating space in the direction along the sealing surface.
With such a configuration, the grease can easily enter into the groove, and the entire contact area can be easily pushed up at the time of supplying the grease, and the discharge of the grease can be promoted.

(6) Preferably, in the partial contact area of the facing surface, a plurality of protrusions are formed at intervals in the circumferential direction.
By providing such a protrusion, a gap can be formed between the opposing surface of the contact portion and the seal surface, and when supplying grease, grease can be introduced into the gap to push up the entire contact area, Can be discharged.

(7) Preferably, the protrusion is disposed closer to the lubricating space than an end portion of the pressing member located on the lubricating space side in a direction along the seal surface.
With such a configuration, the end of the contact portion on the side of the lubrication space can be reliably floated from the seal surface to form a gap, and grease can be introduced into the gap.

  According to the sealing structure of the present invention, the ability to discharge old grease when supplying new grease can be enhanced in the sealing structure that seals the lubrication space filled with grease.

It is a partial disassembled perspective view of the cross axis joint to which the sealing structure concerning a 1st embodiment is applied. It is a side view (partially sectional view) of a cross joint. It is sectional drawing of sealing structure. It is sectional drawing of the sealing member of sealing structure. It is sectional drawing which shows the effect | action of the 1st lip | rip part of a sealing member. (A) is an E arrow view of FIG. 5, (b) is an F arrow view of FIG. (A) is sectional drawing which shows the 1st lip part to which supply pressure of grease is not given, (b) is a sectional view showing the 1st lip part to which supply pressure of grease is given. It is explanatory drawing which shows the change of the surface pressure of all the contact areas with respect to the 1st sealing surface of sealing structure. It is drawing equivalent to FIG. 6 which shows the modification of the groove | channel of a 1st lip part. It is sectional drawing which expands and shows the 1st lip part of the sealing structure which concerns on 2nd Embodiment. It is sectional drawing of the sealing structure which concerns on a prior art. It is sectional drawing which shows the lip | rip part to which the supply pressure of grease is given in the sealing structure of a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment
FIG. 1 is a partial exploded perspective view of a cross joint in which the sealing structure according to the first embodiment is applied, and FIG. 2 is a side view (partial cross sectional view) of the cross joint.
The cross joint 20 is used, for example, in a spindle device (not shown) of a steel rolling mill. As shown in FIG. 1, the cross joint 20 includes a cross shaft 2 having four shaft portions 4, a roller bearing portion 5 disposed on each shaft portion 4, and a pair of yokes 17. .

  The cross shaft 2 has a base 3 provided at the center, and four shafts 4 extending in four directions along an axis X and an axis Z orthogonal to each other from the base 3. The cross shaft 2 passes through the center of the base 3 and is rotatable about a central axis C orthogonal to the axial center X and the axial center Z of the shaft 4. In the cross shaft 2, a oil supply passage 13 for supplying a lubricant to the inside of the roller bearing portion 5 is formed in a cross shape along the axial center X and the axial center Z.

  As shown in FIG. 2, greasing holes 3 a and 11 a connected to the greasing passage 13 are respectively formed in the side surface of the base 3 of the cross shaft 2 and the bearing cup 11 of the roller bearing 5 described later. There is. Then, a lubricant is supplied into the roller bearing portion 5 through the oil supply holes 3 a and 11 a and the oil supply passage 13. In the present embodiment, grease is used as a lubricant. Also, the supply of grease may be performed constantly during operation of the device provided with the cross joint 20, or may be performed periodically (for example, every one to three months).

  The roller bearing 5 includes the above-described shaft 4, a plurality of needle rollers 9, and a bearing cup 11. The needle rollers 9 are disposed so as to be capable of rolling along the outer peripheral surface of each shaft 4. The bearing cup 11 is formed in a cylindrical shape with a bottom, and is fitted to the outer peripheral surface of the shaft portion 4 via the needle rollers 9. Accordingly, the needle roller 9 rolls with the inner peripheral surface of the bearing cup 11 as the outer ring raceway and the outer peripheral surface of the shaft 4 as the inner ring race, whereby the bearing cup 11 swings around the axis Z of the shaft 4 It is possible.

  A washer 10 is provided between the tip end surface of the shaft 4 and the bottom surface of the bearing cup 11. A roller guide 8, a seal member 7 and a slinger 6 are disposed on the inner side in the axial center Z direction of the needle roller 9. The sealing structure 1 according to the present invention is configured by the seal member 7, the slinger (second member) 6, and the bearing cup (first member) 11.

FIG. 3 is a cross-sectional view of the sealing structure 1. FIG. 4 is a cross-sectional view showing the seal member 7 in a state not in contact with the slinger 6, ie, in a natural state.
The sealing structure 1 is a space in which the needle roller 9 between the shaft 4 and the bearing cup 11 is disposed, and prevents entry of water or the like into a lubrication space filled with grease as a lubricant. Moreover, it is provided in order to prevent the leakage of the lubricant from the said lubricating space to the exterior. In the present specification, the lower side in FIG. 3 is referred to as “axially one side”, and the upper side is referred to as “axially other side”. However, these do not indicate an absolute specific direction in the axial direction, but indicate a relative direction, so one side and the other side may be interchanged and read. The same applies to “one side in the radial direction” and “the other side in the radial direction”.

  The slinger 6 constituting the sealing structure 1 is formed in an annular shape, and is fitted to the outer peripheral surface of the proximal end portion of the shaft portion 4. In the slinger 6, seal surfaces 41, 42 and 43 with which the lip portions 31, 32 and 33 of the seal member 7 contact are formed. In addition, the slinger 6 is a slinger main body 6a formed in a cylindrical shape along the outer peripheral surface of the shaft portion 4 and a first radially outward extension on one axial side (the lower side in FIG. 3) of the slinger main body 6a. An extension 6b and a second extension 6c extending from the distal end side of the first extension 6b to the other side in the axial direction (the upper side in FIG. 3) are integrally formed.

  On the outer peripheral surface of the slinger main body 6a, second and third seal surfaces 42, 43 are formed in line in the axial direction. In addition, a first seal surface 41 is formed on the inner peripheral surface of the second extension 6c. The first seal surface 41 is formed along the axial direction. That is, in the present embodiment, the direction along the first seal surface 41 coincides with the axial direction.

  The slinger 6 is provided with a third extension 6d that extends further outward in the radial direction from the second extension 6c. The outer peripheral surface of the second extending portion 6c and the side surface on the other side in the axial direction of the third extending portion 6d respectively face the end portion of the bearing cup 11 with a gap. This gap is a seal gap that prevents water or the like from entering between the slinger 6 and the bearing cup 11.

  The seal member 7 includes a cored bar (fixed portion) 34 and lip portions 31, 32, 33. The cored bar 34 is fixed by being fitted to the inner peripheral surface of the bearing cup 11. The cored bar 34 includes a first cored bar 34a having a first cylindrical portion 34a1 and a first ring portion 34a2 bent radially inward from the other axial end of the first cylindrical portion 34a1; The second cored bar 34b has a second cylindrical portion 34b1 and a second ring portion 34b2 that is bent radially inward from an end portion on one axial side of the second cylindrical portion 34b1. The second cylindrical portion 34b1 is overlapped on the inner side in the radial direction of the first cylindrical portion 34a1, and the second cored bar 34b is the first cored bar 34a by caulking the end portion on one side in the axial direction of the first cylindrical portion 34a1. It is fixed to

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

  The second lip portion 32 extends from the first annular portion 34a2 to one side in the axial direction. The radially inner side surface of the second lip 32 contacts the second sealing surface 42 of the slinger 6. A recess 32 a is formed on the radially outer side surface of the second lip portion 32, and a garter spring (second pressing member) 52 is provided in the recess 32 a. The garter spring 52 is formed by forming a coil spring in a ring shape, and is accommodated in the recess 32 a of the second lip portion 32 in a state of being elastically deformed in the extending direction, and elastically returns in the contracting direction. The lip portion 32 is pressed to the second seal surface 42 side.

  The third lip portion 33 extends from the radial inner end of the second annular portion 34b2 to one axial side. The radially inner side surface of the third lip 33 contacts the third seal surface 43 of the slinger 6. The third seal surface 43 is formed in an inclined surface (conical surface) in which the outer diameter gradually decreases from one axial direction to the other. The third lip 33 may be omitted. Further, in the present embodiment, the third seal surface 43 is formed in a conical shape, but for example, the third seal surface 43 may be a cylindrical surface parallel to the axial direction.

  The first lip portion 31 has a diameter from the base (first portion) 31 a extending in the same direction from the side surface of the second annular portion 34 b 2 in the axial direction and the extending end (one end portion in the axial direction) of the base 31 a A connection portion (second portion) 31b extending outward in the direction, and a contact portion (third portion) 31c extending in the other axial direction from the extending end (radially outer end portion) of the connection portion 31b .

A radially outer side surface (peripheral surface) of the contact portion 31 c is an opposing surface 31 c 2 facing the first seal surface 41 of the slinger 6, and at least a part thereof contacts the first seal surface 41.
Based on the first seal surface 41, the base 31a is disposed on the opposite side to the first seal surface 41 across the contact portion 31c. Further, the connection portion 31 b connects end portions of the base portion 31 a and the contact portion 31 c on the side of the lubricating space (one side in the axial direction) in the direction along the first seal surface 41.

  A garter spring (first pressing member) 51 is housed in a space (housing space) S surrounded by the base portion 31a, the connection portion 31b, and the contact portion 31c. Further, an opening A for inserting the garter spring 51 into the housing space S is formed between the base portion 31 a and the contact portion 31 c. The opening A is open to the other side in the axial direction. The garter spring 51 is formed by forming a coil spring in a ring shape, and is accommodated in the accommodation space S in a state of being elastically deformed in the contracting direction, and elastically returns in the extending direction to elastically contact the contact portion 31c. It is comprised so that it may press on the surface 41 side.

FIG. 5 is a cross-sectional view showing the operation of the first lip portion 31 of the seal member 7.
The contact portion 31c of the first lip portion 31 is inclined radially outward in a state where the contact portion 31c is not in contact with the first seal surface 41 of the slinger 6, as shown by a solid line in FIG. In this state, the width W1 of the opening A between the base 31a and the contact portion 31c is formed relatively wide. Specifically, the radial position a of the tip inner peripheral edge (side edge) 31 d of the contact portion 31 c which is one end edge of the opening A is larger in diameter than the radial position b of the radial outer end portion of the garter spring 51 It is arranged outside the direction. Therefore, the garter spring 51 can be easily inserted into the accommodation space S through the opening A.

  On the other hand, as shown by a two-dot chain line in FIG. 5, in the state where the contact portion 31c is in contact with the first seal surface 41, the contact portion 31c is elastically deformed radially inward and an opening between the contact portion 31c and the base 31a. The width W2 of A is reduced. The radial position a ′ of the tip inner peripheral edge 31 d of the contact portion 31 c is disposed radially inward of the radial position b of the radial outer end of the garter spring 51. Therefore, the garter spring 51 is difficult to be separated from the accommodation space S, and the first lip portion 31 can be reliably brought into contact with the first seal surface 41. In particular, the garter spring 51 is easily deformed because it is elastically deformed in the contracting direction, and is easily detached from the accommodation space S. However, by reducing the width of the opening A, the detachment of the garter spring 51 can be assured. It can be prevented.

  In addition, at the tip inner peripheral edge 31d of the contact portion 31c in the first lip portion 31, a bulging portion 31c1 that bulges radially inward is formed. By forming such a bulging portion 31c1, when the contact portion 31c is brought into contact with the first seal surface 41, the width W2 of the opening A is made easy while elastically deforming the contact portion 31c radially inward. It can be made as small as possible.

  As shown in FIG. 3, the seal member 7 of the present embodiment contacts the first seal surface 41 in which the first lip portion 31 is disposed radially inward, and the second lip portion 32 and the third lip portion Reference numeral 33 is in contact with the second and third sealing surfaces 42 and 43 disposed radially outward. Therefore, even if the shaft 4 moves in the axial direction with respect to the bearing cup 11, the sealing performance does not deteriorate.

  In addition, when the shaft portion 4 moves in the radial direction with respect to the bearing cup 11, the first lip portion 31 moves in a direction away from the first seal surface 41 on one side in the radial direction of the shaft portion 4. The second and third lip portions 32, 33 move in a direction approaching the second and third seal surfaces 42, 43, and on the other side in the radial direction, the second and third lip portions 32, 33 are second, third While moving away from the sealing surfaces 42, 43, the first lip portion 31 moves toward the first sealing surface 41. Therefore, it is possible to ensure sealing performance substantially uniformly on both sides of the sealing member 7 in the radial direction.

  In the slinger 6, the first and second seal surfaces 42 and 43 are formed on the outer peripheral surface of the slinger main body 6a, and the first seal surface 41 disposed radially outward of the second and third seal surfaces 42 and 43 is It is formed on the inner circumferential surface of the second extension 6c. Therefore, the second and third seal faces 42 and 43 and the first seal face 41 are disposed to be opposed to each other with a space in the radial direction, and there is a space for placing the seal member 7 between them. It is formed. By inserting the seal member 7 in the space, the lip portions 31 to 33 can be brought into contact with the first seal surface 41 and the second and third seal surfaces 42 and 43 which are disposed opposite to each other in the radial direction. . Further, since the first seal surface 41 and the third seal surface 43 are disposed at overlapping positions in the axial direction, the axial dimension of the sealing structure 1 can be made as small as possible.

  As described above, the sealing structure 1 of the present embodiment seals the internal space (lubricated space) of the roller bearing unit 5 which is grease-lubricated. Hereinafter, as shown in FIG. 3, with respect to the direction (axial direction) along the first seal surface 41, the inner side of the roller bearing portion 5 rather than the first lip portion 31 is also referred to as the “lubrication space side”. The outer side than 31 is also referred to as "the lubricating space outer side".

  As shown in FIG. 5, the contact portion 31 c of the first lip portion 31 has a side surface 31 c 2 facing the first seal surface 41 (hereinafter also referred to as “facing surface”), and the facing surface 31 c 2 has a groove 61 are formed. The groove 61 extends in the axial direction from the end on the lubricating space side of the contact portion 31 c to the outer side of the lubricating space. Further, as shown in FIG. 6, the grooves 61 are formed at a plurality of places at intervals in the circumferential direction of the first lip portion 31. For example, the grooves 61 are formed at sixteen locations at equal intervals in the circumferential direction. The cross section (the cross section in the direction orthogonal to the axial center) of the bottom surface of the groove 61 of the present embodiment is formed in a substantially arc shape.

  Further, the groove 61 includes a deep groove portion 61 a on the lubricating space side and a shallow groove portion 61 b on the lubricating space outer side. The bottom surface of the deep groove portion 61 a and the shallow groove portion 61 b is inclined with respect to the first seal surface 41 so that the lubricating space side becomes deeper in 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 FIG. 6, the circumferential width W3 of the deep groove portion 61a and the shallow groove portion 61b is substantially the same. As described above, the groove 61 has a larger cross-sectional area on the lubricating space side and a smaller cross-sectional area on the lubricating space outer side.

  FIG. 7A shows the contact portion 31 c of the first lip portion 31 in contact with the first seal surface 41. In this state, a part of the other side (the lubricating space outer side) in the axial direction of the opposing surface 31c2 of the contact portion 31c is in contact with the first seal surface 41, and a part of the one axial side (the lubricating space side) is A gap s is opened from the first seal surface 41, and it is in a slightly floating state.

  FIG. 7 (b) shows the first lip 31 when grease is further supplied to the lubrication space. When the grease is supplied to the lubrication space, the first lip portion 31 is pressed in the direction of the arrow c by the supply pressure of the grease, so that it floats from the first seal surface 41 of the opposing surface 31c2 of the contact portion 31c. A portion contacts the first sealing surface 41.

  At this time, as also shown in FIG. 6B, the opposite surface 31c2 of the contact portion 31c is a region on one axial side of the position L of the end of the groove 61 on one axial side (outside the lubrication space) However, the entire contact area R1 is in contact with the first seal surface 41 along the entire circumference (entire surface). In addition, a partial contact in which a region on the other side in the axial direction with respect to the position L of the end portion on one axial side of the groove 61 contacts the first seal surface 41 discontinuously (intermittently) except the groove 61 It is the area R2. That is, the opposing surface 31c2 of the contact portion 31c has the entire contact region R1 and the partial contact region R2.

  Therefore, even if the first lip portion 31 is pressed by the grease in the direction of the arrow c as shown in FIG. 7B, the groove 61 of the partial contact region R2 does not contact the first seal surface 41. Therefore, the grease in the lubrication space enters the groove 61 and pushes up the contact portion 31c by the supply pressure, and is discharged from between the entire contact area R1 of the contact portion 31c and the first seal surface 41 (see arrow d) . Therefore, it is possible to preferably replace the new grease with the old grease in the lubrication space.

  As shown in FIG. 6A, the groove 61 has a larger cross sectional area on the side of the lubrication space than on the outer side of the lubrication space, so the grease easily flows into the groove 61, and Discharge performance can be further enhanced.

  As shown in FIG. 7B, in the facing surface 31c2 of the contact portion 31c, the boundary L between the total contact area R1 and the partial contact area R2 is the end of one side (lubrication space side) of the garter spring 51 in the axial direction. It is located in an axial range D1 between 51b and the center 51a of the garter spring 51. When the boundary L is disposed on one side in the axial direction than the end 51b, it is difficult to push up the entire contact region R1 of the facing surface 31c2 by the grease that has entered the groove 61, and the boundary L is from the center 51a Also when it is arranged on the other side in the axial direction (outside the lubrication space), the sealing performance by the contact portion 31c is reduced due to the relationship of the surface pressure of the entire contact region R1.

FIG. 8 shows a change in the surface pressure of the entire contact region R1 with the first seal surface 41 when the supply pressure of the grease acts on the first lip portion 31.
As shown in FIG. 8A, when the boundary L between the full contact area R1 and the partial contact area R2 coincides with the center 51a of the garter spring 51, the surface of the full contact area R1 with respect to the first seal surface 41. The pressure peaks at the end on the lubricating space side (see point P1). Therefore, water and the like easily infiltrate from the outer side of the lubrication space.

  As shown in FIG. 8B, when the boundary L is closer to the lubrication space than the center 51a of the garter spring 51, the surface pressure of the entire contact region R1 with respect to the first seal surface 41 is the end on the lubrication space outer side. It is a peak (see point P2) in the section. Therefore, the infiltration of water etc. from the lubricating space outer side can be suitably prevented, and the sealing performance can be suitably maintained.

FIG. 9 is a drawing corresponding to FIG. 6 showing a modification of the groove 61 of the first lip portion 31. As shown in FIG.
In the groove 61 according to this modification, the circumferential width W4 of the deep groove portion 61a is formed larger than the width W3 of the shallow groove portion 61b. The cross sectional shape of the deep groove portion 61a is formed in a substantially arc shape. According to this modification, the cross-sectional shape of the deep groove portion 61 a can be made larger, and the inflow of grease into the groove 61 can be further promoted.

Second Embodiment
FIG. 10 is an enlarged cross-sectional view of a first lip portion of a sealing structure according to a second embodiment.
In the present embodiment, projections 62 are provided at a plurality of locations in the circumferential direction at intervals in the opposing surface 31c2 of the contact portion 31c, instead of the grooves 61. The protrusion 62 is disposed in a range D2 on one side in the axial direction with respect to the end 51b on the one side (lubrication space side) of the garter spring 51 in the axial direction.

  By providing such a projection 62, when the grease is supplied into the lubricating space, the entire opposing surface 31c2 does not come into contact with the first seal surface 41 by the supply pressure of the grease, and the opposing surface 31c2 and the first seal A gap s is always formed between the surface 41 and the surface 41. Therefore, the grease can be discharged by entering the grease into the gap s and pushing up the entire contact area R1 of the contact portion 31c.

  Further, by forming the projection 62 in the range D2, the end portion of the contact portion 31c on the side of the lubricating space can be reliably floated from the first seal surface 41 to form the gap s, and grease can be introduced.

The present invention is not limited to the above embodiment, but can be modified within the scope of the invention described in the claims.
For example, the number of the grooves 61 and the protrusions 62 formed in the contact portion 31c of the first lip portion 31, the axial length, the circumferential width, the cross sectional shape, and the like can be appropriately changed.

The seal member 7 may be in direct contact with the shaft 4 instead of the slinger 6. The seal member 7 may be fixed to the shaft 4 side and may be configured to be in contact with the bearing cup 11 side.
The sealing structure 1 of the present invention is applicable to other than between the shaft portion 4 and the bearing cup 11 in the cross joint 20.

  1: Sealed structure 6: Slinger (first member) 7: Sealing member 11: Bearing cup (second member) 20: Cross joint, 31: first lip portion 31a: base portion 31b: connection portion 31c: contact portion 31c2: opposite surface 41: first seal surface 51: garter spring (pressing member) 51a: center 51b: end 61: groove 61a: deep groove 61b: shallow groove 62: Projection

Claims (7)

A first member, a second member disposed concentrically with the first member to face the first member in a radial direction, and attached to the first member, the second member being rotatable relative to the first member; A sealing structure for sealing a lubricating space filled with grease between the first member and the second member, the annular sealing member slidingly contacting the sealing surface formed in the member;
The sealing member includes a lip portion having an opposing surface facing the sealing surface, and a pressing member configured to press the opposing surface toward the sealing surface.
The lip portion includes a contact portion having the opposite surface, a base opposite to the seal surface with the contact portion interposed therebetween, and an end of the contact portion on the lubrication space side in a direction along the seal surface A connecting part connecting the part to the base,
The pressing member is disposed in a space surrounded by the contact portion, the base portion, and the connection portion;
When the grease is supplied to the lubricating space, the opposing surface is an entire contact area that contacts the sealing surface on the entire periphery on the outer side of the lubricating space in the direction along the sealing surface, and a direction along the sealing surface And a partial contact area that discontinuously contacts the seal surface in the circumferential direction on the side of the lubricating space.   The boundary between the total contact area and the partial contact area is disposed on the outer side of the lubricating space than the end of the pressing member located on the lubricating space side in the direction along the seal surface. The sealed structure according to 1.   The sealing structure according to claim 2, wherein the boundary is disposed closer to the lubricating space than a center of the pressing member in a direction along the sealing surface.   The groove which extends from the lubricating space side to the outer side of the lubricating space in the direction along the sealing surface is formed in the partial contact area of the opposing surface. Sealed structure described.   The sealing structure according to claim 4, wherein a cross-sectional area of the groove is larger as the lubricating space side in the direction along the sealing surface.   The sealing structure according to any one of claims 1 to 3, wherein a plurality of projections are formed at circumferentially spaced intervals in the partial contact area of the facing surface.   The sealing structure according to claim 6, wherein the protrusion is disposed closer to the lubricating space than an end portion of the pressing member located on the lubricating space side in a direction along the sealing surface.

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