JP2009185980A - Rolling bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly align a rolling bearing unit while preventing the generation of the creep of an outer ring. <P>SOLUTION: This rolling bearing unit is formed by incorporating a ball bearing with a plurality of balls 14 arranged between an inner ring 11 and an outer ring 12 in a bearing box 13 as a pillow type bearing box. The bearing box 13 having an inner diameter surface formed into a recessed spherical surface is fitted on the outer diameter side of the outer ring 12 having an outer diameter surface formed into a projecting spherical surface by clearance-fit. Circumferential grooves 22 are formed at both axial ends of the inner diameter surface of the bearing box 13 of the clearance-fit part P, and O-rings 23 are fitted thereto. The rotation of the outer ring 12 is stopped by an elastic fastening force of the O-rings 23, and the creep of the outer ring 12 is prevented. When the outer ring 12 axially tilts with respect to the bearing box 13, metal contact does not occur on the clearance-fit part P, and a force required for aligning can be reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention comprises a bearing box having a concave spherical inner diameter surface and a rolling bearing in which a plurality of rolling elements are interposed between an inner ring and a convex spherical outer diameter surface. The present invention relates to a rolling bearing unit in which an outer ring of a rolling bearing is fitted on the side.

  A rolling bearing unit in which the outer ring of a rolling bearing is fitted to the inner diameter side of the bearing housing is easy to mount on the rotating shaft and is versatile. Therefore, the rotating shaft of a rotating shaft such as a roller around which a belt-like member such as a belt conveyor or a film is wound. Widely used for support.

In this rolling bearing unit, the fitting surface between the outer ring of the rolling bearing and the bearing housing is a spherical surface, and the fitting surface allows bending (bending or warping) of the rotating shaft and mounting errors. For this reason, it can be applied to a case where the distance between the bearings is large and misalignment is unavoidable (see Patent Document 1).
JP-A-9-250549

Further, in this rolling bearing unit, the outer ring and the bearing housing are usually fitted with a predetermined fit, for example, “tolerance zone class H7” or “tolerance zone” which is a dimensional tolerance and fit standardized by JIS B 0401. Finished to be “Class J7”. As a result, the outer diameter surface of the outer ring and the inner diameter surface of the bearing housing come into contact with each other, and the outer ring is prevented from rotating in the circumferential direction by frictional resistance caused by the contact (for example, non-patent literature) 1).
NTN Corporation Rolling Bearing General Catalog (CAT. No. 2202-VIII / J E-68-71)

  However, in the rolling bearing unit described in Non-Patent Document 1, the contact state between the outer ring and the bearing box may vary due to variations in the finished dimensions of the outer diameter surface of the outer ring and the inner diameter surface of the bearing box. For this reason, when the rotating shaft is inclined and the outer ring is inclined with respect to the axial direction of the bearing housing, the frictional resistance between the outer ring and the bearing housing may be increased. When the frictional resistance increases, the force required for alignment becomes too large, and it is difficult to cope with bending of the rotating shaft, and smooth alignment is not performed.

  Further, when the frictional resistance between the outer ring and the bearing box increases, there is a problem in that the fitting portion between the outer ring and the bearing box is worn during alignment, and a gap is generated in the fitting portion and the outer ring creeps.

  Accordingly, an object of the present invention is to prevent the occurrence of creep of the outer ring and to enable smooth alignment.

  In order to solve the above-mentioned problems, the present invention provides a rolling device in which a plurality of rolling elements are interposed between a bearing box having a concave spherical inner surface and an outer ring having an inner ring and a convex spherical outer surface. In a rolling bearing unit comprising a bearing and an outer ring of the rolling bearing fitted on the inner diameter side of the bearing box, a plurality of circumferential grooves are provided on the inner diameter surface of the bearing box, and the bearing box and the outer ring are fitted together. The ring-shaped member fitted in the circumferential groove is compressed by the circumferential groove and the outer diameter surface of the outer ring.

  According to this configuration, since the ring-shaped member fitted in the circumferential groove of the bearing box is compressed by the circumferential groove and the outer diameter surface of the outer ring, the ring-shaped member presses the outer diameter surface of the outer ring, and the frictional resistance caused by this pressing This prevents the outer ring from creeping. In addition, since the fit between the bearing housing and the outer ring is a loose fit, when the rotating shaft tilts and the outer ring tilts with respect to the axial direction of the bearing housing, the outer ring does not contact the bearing housing, and the outer ring and the bearing housing Thus, the force required for alignment does not increase too much and alignment is performed smoothly. Further, since the outer ring and the bearing housing do not come into contact with each other, wear at the fitting portion does not occur.

  When it is necessary to further reduce the force required for alignment, for example, when the load applied to the rotating shaft is large and the inclination of the outer ring with respect to the axial direction of the bearing box changes frequently, the bearing box and the outer ring A configuration in which grease is applied between the ring-shaped members of the fitting portion can be employed.

  When the grease is applied, the ring-shaped member is pressed against the outer diameter surface of the outer ring, so that the grease is sealed between the ring-shaped members of the fitting portion. With the sealed grease, a lubricating film is formed on the fitting portion, and lubricity is imparted. As a result, a large force is not required when the outer ring is inclined in the axial direction with respect to the bearing housing, and the force required during alignment is reduced and alignment is performed more smoothly.

  In the above configuration, when a rolling bearing is incorporated into the bearing housing, the inner ring or the outer ring may hit the bearing housing, and the assembly may be difficult. Therefore, if a thin portion is formed on the inner diameter surface of the bearing box from one end surface to the central portion in the axial direction, contact with the bearing housing of the inner ring or the outer ring is avoided by this thin portion, and the rolling bearing is attached to the bearing housing. It can be incorporated.

  When adopting a configuration in which a thinned portion is formed on the inner diameter surface of the bearing box, a configuration in which a circumferential groove of the bearing box is provided between the axial central portion and the other end surface of the inner diameter surface of the bearing box is adopted. The circumferential groove is provided so as to avoid the shading portion of the bearing housing.

  If the circumferential groove is provided so as to avoid the slack portion of the bearing box, the ring-shaped member in the circumferential groove does not get in the way when the rolling bearing is incorporated into the bearing box, and assemblability is ensured. Further, when grease is applied between the ring-shaped members, the grease can be sealed between the ring-shaped members of the fitting portion, and the lubricity due to the grease can be maintained.

  Moreover, when using the type in which the outer ring is provided with an oil passage that leads from the inner diameter surface to the outer diameter surface, the outer diameter side opening of the oil passage has a circumference of any two of the plurality of circumferential grooves. By being provided so as to be located at a location that is also removed from between the grooves, it is possible to ensure sealing of the bearing space formed between the inner ring and the outer ring, and to maintain lubricity by grease. .

  When the ring-shaped member is a synthetic rubber O-ring having elasticity, the outer ring can be prevented from rotating by the elastic tightening force of the O-ring. Further, the O-ring is pressed against the outer peripheral surface of the outer ring and is elastically deformed to be in close contact with the outer diameter surface of the outer ring. This close contact makes it difficult for the outer ring to rotate in the circumferential direction and improves the creep prevention performance of the outer ring.

The grease applied to the fitting portion of the bearing housing and the outer ring is composed of base oil (lubricating oil), a thickener, other additives, and the like, and the base oil viscosity is 100 mm ^{2 at} 40 ° C. If the grease consistency is appropriately set, seal the amount of grease necessary for long-term lubrication maintenance without causing a gap in the fitting portion to which the grease is applied. Can do. In addition, since there is no portion that is not in contact with the inner diameter surface of the bearing box and the outer diameter surface of the outer ring, it is held with a high holding force between the ring-shaped members of the fitting portion, and the fitting portion is lubricated over a long period of time. Can be granted.

  As described above, in the rolling bearing unit of the present invention, the ring-shaped member fitted in the circumferential groove on the inner diameter surface of the bearing box is compressed by the circumferential groove and the outer diameter surface of the outer ring, and the fitting between the bearing box and the outer ring is performed. By making the clearance fit, the outer ring does not come into contact with the bearing housing, the force necessary for aligning the rotating shaft does not become too large, and alignment is performed smoothly. Moreover, since the ring-shaped member of the bearing box presses the outer diameter surface of the outer ring, creeping of the outer ring can be prevented by the frictional resistance caused by this pressing.

1 to 3 show a first embodiment of the present invention.
As shown in FIG. 1, the rolling bearing unit of this embodiment includes a ball bearing as a rolling bearing 10 in which a plurality of balls 14 are provided between an inner ring 11 and an outer ring 12 in a pillow type bearing box 13. The balls 14 are held at intervals in the circumferential direction by a cage 15, and the bearing space between the inner ring 11 and the outer ring 12 is sealed with a seal 19.

  The inner ring 11 is formed wider than the width of the outer ring 12 in the axial direction, and has an inner ring raceway 16 on which the ball 14 rolls on the outer diameter surface, from the center of the inner ring raceway 16 to one end. The length is formed longer than the length to the other end.

  A ball set screw 32 is provided outside the bearing housing 13 at one end of the inner ring 11, and the rotary shaft 31 inserted through the inner ring 11 is fixed so as not to rotate relatively. When the ball set screw 32 is tightened, the ball incorporated inside presses the outer peripheral surface of the rotating shaft 31.

  The outer ring 12 is provided with an outer ring raceway 17 on which the ball 14 rolls on its inner diameter surface, and the outer diameter surface forms a convex spherical surface. Seal engagement grooves 21 are provided over the entire circumference on both sides in the axial direction of the outer ring raceway 17 on the inner diameter surface of the outer ring 12, and the outer peripheral edge portion of the annular seal 19 is engaged with the engagement grooves 21.

  The inner peripheral edge of the seal 19 is in sliding contact with the outer diameter surface of the inner ring 11 to seal the bearing space between the inner ring 11 and the outer ring 12. Further, the inner peripheral edge of the annular slinger 20 is fixed to the inner ring 11 on the outer side in the axial direction of the seal 19. A labyrinth seal is formed between the outer peripheral edge of the slinger 20 and the shoulder of the inner diameter surface of the outer ring 12 to prevent moisture and dust from entering the bearing space (see FIG. 2).

  The bearing box 13 into which the outer ring 12 is fitted has a concave spherical surface on the inner diameter surface, and corresponds to a convex spherical surface on the outer diameter surface of the outer ring 12. As shown in FIG. 3, a thinning portion 25 is provided on the inner diameter surface of the bearing housing 13 from one end surface to the center in the axial direction.

  The loose portion 25 is provided in the bearing housing 13 in order to incorporate the ball bearing into the bearing housing 13. That is, when a ball bearing is fitted to the inner diameter side of the bearing housing 13, the inner ring 11 or the outer ring 12 may hit the bearing housing 13 and it may be difficult to incorporate. For this reason, by avoiding the contact between the inner ring 11 and the like and the bearing box 13 (the inner ring 11 and the like are allowed to escape) at the loosening portion 25, the inner ring 11 and the like can be assembled without hitting the bearing box 13.

  In addition, two circumferential grooves 22 and 22 are provided on the inner peripheral surface of the bearing housing 13 over the entire circumference at intervals in the axial direction. Both circumferential grooves 22 are provided between the axially central portion and the other axial end portion of the inner diameter surface of the bearing housing 13 so as to avoid the loose portion 25 of the bearing housing 13.

  A ring-shaped member is fitted in the circumferential groove 22, and this ring-shaped member is an O-ring 23 formed of a synthetic resin having elasticity. The O-ring 23 is compressed by the circumferential groove 22 and the outer diameter surface of the outer ring 12 when the bearing housing 13 is fitted on the outer diameter side of the outer ring 12. By this compression, the O-ring 23 is elastically deformed and comes into close contact with the outer peripheral surface of the outer ring 12, and the outer ring 12 is prevented from rotating with respect to the bearing housing 13 by the elastic tightening force, thereby preventing the outer ring 12 from creeping.

  Here, the bearing box 13 and the outer ring 12 may be fitted as long as the outer ring 12 and the inner diameter surface of the bearing box 13 do not contact each other. Specifically, it is sufficient if it is a clearance fit that becomes a “tolerance zone class G7” that is a dimensional tolerance and fit standardized by JIS B 0401.

  With the clearance fit, when the rotating shaft 31 tilts, the outer ring 12 tilts in the axial direction with respect to the bearing housing 13 while maintaining a gap with respect to the bearing housing 13 via the O-ring 23. As a result, metal contact between the outer ring 12 and the bearing box 13 does not occur in the fitting portion P, and the force required for alignment can be reduced as compared with that described in Non-Patent Document 1.

  Further, when the force required for the alignment needs to be further reduced, for example, when the load applied to the rotating shaft 31 is large and the inclination of the outer ring 12 with respect to the axial direction of the bearing box frequently changes. Grease G may be applied between the O-rings 23 of the mating portion P.

  When the grease G is applied, the O-ring 23 presses the outer diameter surface of the outer ring 12, so that the grease G is sealed in the fitting portion P between the O-ring 23 and the fitting between the O-rings 23. A lubricating film is formed on the portion P. By this lubricating film, when the rotating shaft is inclined and the outer ring 12 is inclined in the axial direction with respect to the bearing housing 13, lubricity is imparted to the fitting portion P, and the adjustment is made as compared with the case where the grease G is not applied. The power required for the heart is reduced, and alignment is performed more smoothly.

The grease G applied between the O-rings 23 of the fitting portion P is generally composed of a base oil (lubricating oil), a thickener, and other additives, and the base oil viscosity is 40. If it is 100 mm ² / s or more at ℃, when the consistency of the grease G is set appropriately, there is no gap in the fitting part P where the grease G is sealed, and it is necessary for long-term lubricity maintenance A large amount of grease can be enclosed.

  Further, since the grease G has no portion that is not in contact with the inner diameter surface of the bearing housing 13 and the outer diameter surface of the outer ring 12, the grease G is held with a high holding force between the O-rings 23 of the fitting portion P. Lubricity can be imparted to the mating portion P over a period of time.

  In the first embodiment, a ball bearing is incorporated in the pillow-shaped bearing box 13 as the rolling bearing 10, but the rolling bearing 10 of the rolling bearing unit according to the present invention is not limited to a ball bearing. Further, the bearing box 13 is not limited to the pillow type, and can be applied to other types such as a flange type and a take-up type.

Next, a second embodiment of the present invention will be described with reference to FIG.
In the rolling bearing unit according to this embodiment, an oil passage that leads from the inner diameter surface to the outer diameter surface is provided in the outer ring, and the outer diameter side opening of the oil passage is removed from between the two circumferential grooves. It differs from the first embodiment described above in that it is provided so as to be located at a location. Other configurations are the same as those of the first embodiment. In addition, the same code | symbol is used for the structure considered same as 1st Embodiment.

  According to this configuration, the grease G sealed in the bearing space formed between the inner ring 11 and the outer ring 12 does not leak through the oil passage 24 and lubricates the fitting portion P between the O-rings 23. Sex can be maintained.

The longitudinal cross-sectional view which shows the rolling bearing unit which concerns on 1st Embodiment Front view showing the same rolling bearing unit Longitudinal sectional view showing the bearing housing of the rolling bearing unit A longitudinal sectional view showing a rolling bearing unit according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rolling bearing 11 Inner ring 12 Outer ring 13 Bearing box 14 Ball 15 Cage 16 Inner ring raceway 17 Outer ring raceway 19 Seal 20 Slinger 21 Seal locking groove 22 Circumferential groove 23 O-ring 24 Oil passage 25 Slack part 31 Rotating shaft 32 Ball set screw P Mating part G Grease

Claims (6)

A rolling bearing in which a plurality of rolling elements (14) are interposed between a bearing box (13) having a concave spherical inner surface and an inner ring (11) and an outer ring (12) having a convex spherical outer surface. (10), in which the outer ring (12) of the rolling bearing (10) is fitted on the inner diameter side of the bearing box (13),
A plurality of circumferential grooves (22) are provided on the inner diameter surface of the bearing housing (13), and the fitting of the bearing housing (13) and the outer ring (12) is a clearance fit, and the circumferential groove (22) A rolling bearing unit characterized in that a ring-shaped member (23) fitted in a ring is compressed by the circumferential groove (22) and the outer diameter surface of the outer ring (12).   The rolling bearing unit according to claim 1, wherein grease is applied between the ring-shaped members of the fitting portion of the bearing box (13) and the outer ring (12).   A shading portion (25) is formed on the inner diameter surface of the bearing housing (13) from the one end surface to the axial central portion, and the circumferential groove (22) is formed in the axial central portion of the inner diameter surface of the bearing housing (13) and others. The rolling bearing unit according to claim 1, wherein the rolling bearing unit is provided between the end faces.   The outer ring (12) is provided with an oil passage (24) leading from the inner diameter surface to the outer diameter surface, and the outer diameter side opening of the oil passage (24) is one of the plurality of circumferential grooves (22). The rolling bearing unit according to claim 3, wherein the rolling bearing unit is provided so as to be located at a position deviated from between the two circumferential grooves.   The rolling bearing unit according to any one of claims 1 to 4, wherein the ring-shaped member is an elastic synthetic rubber O-ring (23). 3. The rolling bearing unit according to claim 2, wherein the grease has a base oil viscosity of 100 mm ² / s or more at 40 ° C. 3.

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