JP5215200B2 - Rolling bearing - Google Patents

Description

  The present invention relates to a rolling bearing provided with a seal member that forms a grease-filled space between an inner ring and an outer ring.

  As a rolling bearing of this type, as shown in FIG. 4, the outer peripheral portion of the seal member 43 is held in the seal groove 42 of the outer ring 41, and the peripheral groove 45 is formed on the outer periphery of the inner ring 44. A branch portion is provided at a position near the height of the radial surface 46, and a main lip 47 that contacts the outer groove wall of the circumferential groove is formed by a portion protruding in the inner diameter direction from the branch portion. A sub lip 48 is formed by a portion protruding to the side, and a labyrinth seal 50 is formed between a tip portion of the sub lip 48 and a step portion 49 whose outer diameter is reduced from the inner ring outer diameter surface 46 of the inner ring 44. Yes (Patent Document 1).

  When the rolling bearing rotates at a high speed, the bearing internal pressure increases. Therefore, if the sealing performance is insufficient, the tendency of grease to be discharged to the outside together with air is increased. In the rolling bearing of Patent Document 1, the internal pressure of the bearing is relieved by the labyrinth seal 50 upstream of the main lip 47 in the grease leakage flow (conceptually indicated by the arrow in the figure). Even if the tightening margin of the lip 47 is set to be relatively small, good sealing performance can be obtained and torque can be reduced. In addition, since the grease reservoir having a relatively large volume is formed by the main lip 47, the sub lip 48, and the inner surface of the circumferential groove 45, the grease reservoir acts to alleviate the pressure at which the grease leaks. For this reason, the rolling bearing of Patent Document 1 can further reduce the torque. Further, in the rolling bearing of Patent Document 1, the labyrinth seal 50 is opened at a position closer to the inner diameter direction than the outer edge of the inner ring outer diameter surface 46, so that the grease flowing along the inner ring outer diameter surface 46 is applied to the labyrinth seal 50. It is difficult to enter and has excellent grease leakage prevention properties.

JP 2006-170313 A

  However, when a rolling bearing such as that disclosed in Patent Document 1 is used to supply grease from the outside to the grease-filled space, a specific problem that old grease is difficult to be discharged occurs. That is, the grease supply is performed by sending new grease from the outside into the grease enclosure space with the seal member mounted, thereby pushing out the old grease from between the seal member and the inner ring. In the rolling bearing as in Patent Document 1, it is difficult for old grease to enter the labyrinth seal. Further, since the main lip comes into contact with the outer groove wall of the circumferential groove, even if the main lip is pushed by old grease, a leak gap is not easily generated between the main lip and the outer groove wall. Further, the larger the grease reservoir, the more difficult it is for old grease to be discharged to the outside.

  Therefore, the object of the present invention is to provide a seal member that forms a grease-filled space between the inner ring and the outer ring, and in a rolling bearing that supplies grease to the grease-filled space from the outside, it is easy to discharge old grease to the outside. In addition, the torque should be reduced.

  In order to solve the above-described problems, the present invention includes a seal member that forms a grease-filled space between an inner ring and an outer ring, holds the seal member on the inner periphery of the outer ring, and externally inserts grease into the grease-filled space. In the rolling bearing for supplying grease, a step portion whose outer diameter is reduced from the outer surface of the inner ring is formed on the outer periphery of the inner ring, and the inner lip portion of the seal member is in contact with the step portion and the main lip. Provided to branch to a sub lip that forms a labyrinth seal between the outer ring and the outer ring at a position closer to the inner ring raceway than the lip, and a space in which the main lip can move is provided on the outer side in the inner ring axial direction of the main lip. The structure which has is adopted.

  According to the configuration of the present invention, the internal pressure during operation of the bearing is relaxed by the labyrinth seal upstream of the grease leakage flow from the main lip. Sealing performance can be obtained and torque can be reduced. Further, since the grease reservoir is formed by the main lip, the sub lip, and the stepped portion, the grease reservoir acts to alleviate the pressure at which the grease leaks. This also makes it possible to reduce the torque. Considering the state where the main lip contacts the step portion at the beginning of grease supply, there is a space in which the main lip can move on the outer side in the inner ring axial direction of the main lip. Therefore, even if the greasing progresses, a grease leakage gap is easily formed between the main lip pressed by the grease and the inner ring, so that old grease is easily discharged to the outside.

  The rolling bearing according to the present invention can be used for, for example, an application for supporting a ball screw of a machine tool.

  The present invention can be applied to, for example, deep groove ball bearings, angular ball bearings, roller bearings, thrust bearings, double row bearings, etc., regardless of the type of bearing.

  As described above, the present invention includes a seal member that forms a grease-enclosed space between an inner ring and an outer ring, holds the outer periphery of the seal member on the inner periphery of the outer ring, and externally inserts grease into the grease-enclosed space. In the rolling bearing that supplies grease, a stepped portion that is reduced in diameter from the inner ring outer diameter surface is formed on the outer periphery of the inner ring, and the inner peripheral portion of the seal member is contacted with the stepped portion by the main lip. Also provided to branch to a secondary lip that forms a labyrinth seal between the inner ring and the outer periphery of the inner ring at a position close to the inner ring raceway, and the main lip has a space in which the main lip can move on the outer side in the axial direction of the inner ring As a result, the grease leakage gap is easily formed between the main lip and the stepped portion, so that old grease is easily discharged to the outside, and the internal pressure is reduced and the main pressure is reduced by the labyrinth seal. It is possible to reduce the torque by grease reservoir formed by the flop and the auxiliary lip and the step portion.

Sectional drawing which showed embodiment of the rolling bearing which concerns on this invention by the cut surface of an axial plane (a bearing central axis is included) Enlarged view of the vicinity of the outer periphery of the seal member of FIG. Sectional drawing of the principal part which showed an example which supports the ball screw of a machine tool using the rolling bearing which concerns on this invention Sectional view showing a conventional example with a cut surface of an axial plane (including the bearing center axis)

  As shown in FIGS. 1 and 2, the rolling bearing according to the embodiment supplies grease to the grease sealing space 3 from the outside, and the seal member 4 that forms the grease sealing space 3 between the inner ring 1 and the outer ring 2. And a greasing path 5 for the purpose.

  A ball is used as the rolling element 6. The contact angle between the rolling element 6 and the races 7 and 8 of the inner and outer rings is 90 °.

  A stepped portion 10 whose outer diameter is reduced from the inner ring outer diameter surface 9 is formed on the outer periphery of the inner ring 1. The inner ring outer diameter surface 9 is an outer peripheral portion of the inner ring 1 between the inner ring raceway 7 and the stepped portion 10.

  A seal member 4 is held on the inner periphery of the outer ring 2. A seal groove 11 is formed on the inner periphery of the outer ring 2. The seal member 4 includes an inner edge 13a of the outer peripheral portion that abuts inward in the axial direction against the inner diameter enlarged portion 12 of the outer ring 2, a neck portion 14 that extends in the inner diameter direction from the outer edge 13b of the outer peripheral portion, and a shaft extending from the neck portion 14 The cross-sectional shape has an inner peripheral portion with a wide directional width. Here, the “axial direction” refers to a direction along the bearing central axis. “Axial inward” refers to a direction approaching in the axial direction from the outside to the inside of the bearing. The “inner diameter direction” refers to a direction approaching the bearing center axis from the outside when a straight line orthogonal to the bearing center axis is considered on the cut surface of the axial plane.

  The inner peripheral portion of the seal member 4 forms a labyrinth seal 16 between the main lip 15 that contacts the stepped portion 10 of the inner ring 1 and the outer periphery of the inner ring 1 at a position closer to the inner ring raceway 7 than the main lip 15. It is provided to branch to the auxiliary lip 17.

  The main lip 15 protrudes from the branch portion in the inner diameter direction. An end 18 which is an inner diameter direction and an axially inward end of the main lip 15 forms a contact seal with the step portion 10 of the inner ring 1. Other portions of the main lip 15 are separated from the stepped portion 10.

  The sub lip 17 protrudes inward in the axial direction from the branch portion. The auxiliary lip 17 is provided at a position closer to the outer diameter direction than the extension line L of the inner ring outer diameter surface 9. Here, the “outer diameter direction” refers to a direction away from the bearing central axis to the outside when a straight line orthogonal to the bearing central axis is considered on the cut surface of the axial plane.

  When the auxiliary lip 17 is provided as described above, as a result, the auxiliary lip 17 forms the labyrinth seal 16 at a position closer to the outer diameter direction than the outer edge 19 of the inner ring outer diameter surface 9. If the labyrinth seal 16 is only formed at a position closer to the outer diameter direction than the outer edge 19 of the inner ring outer diameter surface 9, the branch portion is provided at a position closer to the inner diameter direction than the outer edge 19, and the auxiliary lip 17 is provided. You may provide so that it may incline in an outer-diameter direction toward an axial direction inward.

  The inner periphery of the sub lip 17 and the inner surface of the main lip 15 are provided at positions closer to the inner side in the axial direction than the outer edge 20 of the stepped portion 10.

  The inner peripheral tip portion 21 of the sub lip 17 has a tapered cross section with an angle α of less than 90 ° with respect to the inner ring outer diameter surface 9.

  The grease supply path 5 is provided so as to open between the outer ring raceway 8 and the inner diameter enlarged portion 12 in the inner circumference of the outer ring 1. The greasing path may be provided so as to be capable of being lubricated from the outside in a state where the grease enclosure space 3 is formed.

  The inner ring 1 has a shape in which a space allowing free deformation when the main lip 15 is pushed by the grease communicates with the main lip 15 in contact with the stepped portion 10.

  In particular, the inner ring 1 and the seal member 4 are provided such that the main lip 15 is exposed in the axial direction with respect to the outside, as is apparent from FIG.

  A synthetic rubber projection 23 attached to the outer surface of the cored bar 22 is formed on the outer periphery of the seal member 4. As shown in FIG. 2, the outer groove wall 24 and the protrusion 23 of the seal groove 11 are hooked in the axial direction by wall surfaces forming angles β1 and β2 of 90 ° or less from the bottom side of the seal groove 11 with respect to the axial direction. It is provided to fit. As the core bar 22, a pressed product of a thin steel plate is used. As the synthetic rubber, conventionally known appropriate blends are used.

  Press-fitting fitting portions 25 and 26 are provided on a portion of the inner periphery of the outer ring 2 that is closer to the axial direction outward than the seal groove 11 and an outer peripheral portion of the seal member 4. Here, “axially outward” refers to a direction away from the inside of the bearing to the outside in the axial direction.

  The press fitting part 25 on the outer ring 2 side has a cylindrical surface centered on the bearing central axis. In order to facilitate the press-fitting fitting inward in the axial direction, the press-fitting fitting portion 25 can be a conical surface whose inner diameter increases as it advances outward in the axial direction.

  The press-fitting fitting portion 26 on the seal member 4 side is given a tightening allowance δ with respect to the press-fitting fitting portion 25 on the outer ring 2 side, as shown by a two-dot chain line in FIG. In order to facilitate the press-fitting fitting inward in the axial direction, the press-fitting fitting part 26 comes into contact with the press-fitting fitting part 25 from a conical surface whose outer diameter increases as it advances outward in the axial direction. ing.

  The press-fitting fitting portion 26 on the seal member 4 side is formed of synthetic rubber attached to the outer surface of the cored bar 22.

  The axial width A between the inner edge 13a and the outer edge 13b of the outer peripheral portion of the seal member 4 and the axial width B of the neck portion 14 are provided in a relationship of A / B ≧ 5.

  In the rolling bearing according to the embodiment as described above, the internal pressure during the operation of the bearing is relaxed by the labyrinth seal 16 on the upstream side of the grease leakage flow Va from the main lip 15. Therefore, the rolling bearing according to the embodiment can obtain a good sealing performance and reduce the torque even if the tightening margin of the end portion 18 of the main lip 15 is set to be relatively small.

  Further, a grease reservoir 27 is formed by the main lip 15, the sub lip 17 and the stepped portion 10. The grease reservoir 27 acts to alleviate the pressure at which the grease leaks. Also from this, the rolling bearing according to the embodiment can reduce the torque.

  When the grease supply using the grease supply path 5 is performed, first, the main lip 15 is in contact with the step portion 10 whose outer diameter is reduced from the outer diameter surface 9 of the inner ring. At this time, the main lip 15 has no portion facing the inner ring 1 outward in the axial direction, and the whole faces the outer space. Thus, since the main lip 15 has a space in which the main lip 15 can move on the outer side of the main lip 15 in the inner ring axial direction, the greasing progresses as compared with the case where the main lip contacts the outer groove wall as shown in FIG. Thus, a grease leakage gap is easily formed between the main lip 15 pressed by the grease and the inner ring 1. Therefore, in the rolling bearing according to the embodiment, old grease is easily discharged to the outside.

  Further, since the labyrinth seal 16 is formed between the sub lip 17 and the inner ring outer diameter surface 9, the labyrinth seal is opened to a position closer to the inner diameter direction than the inner ring outer diameter surface as shown in FIG. The old grease that flows along the inner ring outer diameter surface 9 tends to enter the labyrinth seal 16. Therefore, in the rolling bearing according to the embodiment, old grease is more easily discharged to the outside.

  Since the auxiliary lip 17 is provided at a position closer to the outer diameter direction than the extension line L of the inner ring outer diameter surface 9, the old grease flowing along the inner ring outer diameter surface 9 tends to go directly from the labyrinth seal 16 directly to the main lip 15. . Therefore, in the rolling bearing according to the embodiment, old grease is easily discharged to the outside as compared with the rolling bearing according to the embodiment in which the base side of the sub lip 17 is located closer to the inner diameter direction than the outer edge 19 of the inner ring outer diameter surface 9.

  Since the inner periphery of the sub lip 17 and the inner surface of the main lip 15 are provided at positions closer to the inner side in the axial direction than the outer edge 20 of the stepped portion 10 of the inner ring 1, old grease flowing along the outer diameter surface 9 of the inner ring It becomes easy to enter the labyrinth seal 16, and the capacity of the grease reservoir 27 is smaller than that in which the main lip contacts the outer groove wall as shown in FIG. Therefore, in the rolling bearing according to the embodiment, particularly old grease is easily discharged to the outside.

  Since the inner circumferential tip 21 of the secondary lip 17 has a tapered cross section with an angle α of less than 90 ° with respect to the inner ring outer diameter surface 9, old grease flowing along the inner ring outer diameter surface 9 It is difficult to flow to the side. Therefore, in the rolling bearing according to the embodiment, the old grease is more easily discharged to the outside as compared with the case where the angle α of the inner peripheral tip portion of the sub lip is 90 ° or more.

  Since the main lip 15 is exposed in the axial direction with respect to the outside, the old grease leaked from between the end portion 18 of the main lip 15 and the stepped portion 10 flows from the main lip 15 in the downstream region of the flow Va and the grease. There is no stagnation in the pool. Compared with the one provided with such a labyrinth seal or the like, there is no resistance that the old grease flowing along the inner ring outer diameter surface 9 is directed between the end portion 18 of the main lip 15 and the step portion 10. Therefore, in the rolling bearing according to the embodiment, old grease is more easily discharged to the outside.

  The outer groove wall 24 of the seal groove 11 and the protrusion 23 of the seal member 4 are hooked in the axial direction by the wall surfaces forming angles β1 and β2 of 90 ° or less from the bottom side of the seal groove 11 with respect to the axial direction. Since the protrusions 23 are provided, the protrusions 23 are not easily slid along the outer groove wall 24, and the seal member 4 is difficult to come off during grease supply.

  Each of the angles β1 and β2 is preferably an acute angle satisfying β1 ≧ β2. This is because it can be caught securely like a bull hook.

  Incidentally, conventionally, as shown in FIG. 4, a seal groove is formed on the inner periphery of the outer ring, a synthetic rubber protrusion attached to the core metal is formed on the outer periphery of the seal member, and the protrusion is press-fitted into the seal groove. Thus, the seal member is held on the inner periphery of the outer ring. The outer groove wall of the seal groove has a cross-sectional shape with a curvature that escapes outward in the axial direction toward the inner diameter direction. The protrusion press-fitted into the seal groove is in a state where the contact area having an arcuate cross section is compressed in the axial direction and the radial direction by the outer groove wall. In the conventional seal member mounting structure, when the grease is supplied as described above, the seal member receives pressure for extruding the grease. At this time, since the protrusion made of synthetic rubber is in close contact with the outer groove wall of the seal groove only by the elastic compressive force, the protrusion slides out of the seal groove along the outer groove wall from the above-mentioned cross-sectional shape, It can be said that the structure is easy to come off. In the present invention, it is possible to adopt a conventional seal member mounting structure as shown in FIG.

  Since the press-fitting fitting portions 25 and 26 are provided on the inner circumference of the outer ring 2 that is closer to the outer side in the axial direction than the seal groove 11 and the outer circumference of the seal member 4, the press-fitting fitting portion 25 is used when grease is applied. , 26 become resistance to the tilting of the seal member 4 and the outward movement in the axial direction. Therefore, in the rolling bearing according to the embodiment, the seal member 4 is less likely to come off compared to the conventional example as shown in FIG.

  In addition, the press-fitting fitting portions 25 and 26 prevent the seal member 4 from moving outward in the axial direction, and the protrusion 23 moves outward in the axial direction against the resistance of the press-fitting fitting portions 25 and 26. It is preferable to be provided so as to be caught by the outer groove wall 24. This is because the protrusion 23 cannot be compressed in the seal groove 11 due to the angular relationship between β1 and β2, and it is difficult to form the protrusion 23 and the outer groove wall 24 with a dimensional accuracy that maintains the contact state. It is.

  Since the press-fitting fitting portion 26 on the seal member 4 side is formed of synthetic rubber adhered to the outer surface of the core metal 22, press-fitting fitting is easy, and the press-fitting fitting portions 25 and 26 form a contact seal. Therefore, the rolling bearing according to the embodiment not only makes it difficult for the seal member 4 to come off, but also ensures that old grease is discharged from the main lip 15 side.

  An inner edge 13a of the outer peripheral portion that abuts the seal member 4 inward in the axial direction against the inner diameter enlarged portion 12 of the outer ring 2, a neck portion 14 extending in the inner diameter direction from the outer edge 13b of the outer peripheral portion, and a shaft extending from the neck portion 14 When the cross-sectional shape has an inner peripheral part with a wide directional width, and the axial width A between the inner edge 13a and the outer edge 13b and the axial width B of the neck part 14 are provided in a relationship of A / B ≧ 5, As described above, the protrusion 23 and the press-fitting fitting portions 25 and 26 can reliably prevent the seal member 4 from coming off during grease supply. That is, conventionally, the seal member has an inner edge of the outer peripheral portion that abuts inward in the axial direction against the inner diameter enlarged portion of the outer ring, a neck portion that extends in the inner diameter direction from the outer edge of the outer peripheral portion, and an axial width from the neck portion. In general, the cross-sectional shape has a widened inner periphery. When such a general cross-sectional shape is employed, the conventional example as shown in FIG. 4 does not have a press-fitting fitting portion, and therefore has a relationship of A / B ≦ 3. The rolling bearing according to the embodiment can surely prevent the seal member 4 from coming off as compared with the case where the press-fitting fitting portions 25 and 26 are provided while maintaining this relationship.

  The rolling bearing which concerns on embodiment can be used as the bearing 31 which supports the ball screw 30 of a machine tool so that it may illustrate in FIG. The illustrated example illustrates a ball screw 30 that supports a screw shaft 33 rotated by a motor 32 on a stationary member 34 and feeds a work table 36 connected to a nut 35. When the nut 35 is driven by a motor, the rolling bearing according to the embodiment can be used to support the nut 35 with respect to the connection housing of the work table 36.

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Grease enclosure space 4 Seal member 5 Grease path 7 Inner ring raceway 9 Inner ring outer diameter surface 10 Step part 11 Seal groove 12 Inner diameter enlarged part 13a Inner edge 13b Outer edge 14 Neck part 15 Main lip 16 Labyrinth seal 17 Sub lip 19 Outer edge 20 Outer edge 21 Inner peripheral tip 22 Core metal 23 Projection 24 Outer groove wall 25, 26 Press fit fitting part 27 Grease reservoir 30 Ball screw 31 Bearing 33 Screw shaft 34 Stationary member 35 Nut 36 Work table

Claims (5)

In a rolling bearing that includes a seal member that forms a grease-filled space between an inner ring and an outer ring, holds the seal member on the inner periphery of the outer ring, and supplies grease to the grease-filled space from the outside. A step portion whose outer diameter is reduced from the outer diameter surface of the inner ring is formed, and a main lip that contacts the step portion, and a position closer to the inner ring raceway than the main lip, the inner ring portion of the seal member The main lip is pushed by the grease during lubrication between the main lip and the inner ring that are in contact with the stepped portion. A rolling bearing characterized in that a space allowing free deformation at the time and allowing the main lip to move outwardly in the inner ring axial direction during lubrication leads to the outside . Forming the labyrinth seal between the secondary lip and the inner ring outer diameter surface ;
The sub lip is provided at a position closer to the outer diameter direction than the extension line of the inner ring outer diameter surface ,
The inner periphery of the sub lip and the inner surface of the main lip are provided at positions closer to the inner side in the axial direction than the outer edge of the stepped portion ,
Rolling bearing according to 請 Motomeko 1 entirety of the main lip in contact with the step portion is exposed in the axial direction with respect to the outside. The rolling bearing according to claim 2 , wherein an inner peripheral front end portion of the sub lip has a tapered cross section having an angle of less than 90 ° with respect to the outer surface of the inner ring. A seal groove is formed on the inner periphery of the outer ring, and a synthetic rubber protrusion attached to the outer surface of the core metal is formed on the outer periphery of the seal member. The outer groove wall of the seal groove and the protrusion are , Provided so as to be hooked in the axial direction on the wall surface forming an angle of 90 ° or less from the bottom side of the seal groove with respect to the axial direction ,
A press-fitting fitting portion is provided on a portion of the inner periphery of the outer ring that is closer to the axial direction outward than the seal groove, and an outer peripheral portion of the seal member ,
The press-fitting fitting portion on the seal member side is formed of synthetic rubber attached to the outer surface of the core metal ,
An inner edge of the outer peripheral portion that abuts the seal member axially inward with respect to an inner diameter enlarged portion of the outer ring, a neck portion extending in an inner diameter direction from an outer edge of the outer peripheral portion, and an axial width from the neck portion. A cross-sectional shape having the widened inner periphery, and an axial width A between the inner edge and the outer edge.
The rolling bearing according to claim 1, wherein the axial width B of the neck portion is provided in a relationship of A / B ≧ 5. Rolling bearing according to any one of claims 1 to support the machine tool of the ball screw 4.

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