JP2013072451A - Deep groove ball bearing and bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a torque loss in a deep groove ball bearing superior in lubricity.SOLUTION: A ball 31 is incorporated between a track groove 12 of an outer race 11 and a track groove 22 of an inner race 21, and the ball 31 is held by a cage 40. The cage 40 is formed of a first divided cage 41 and a second divided cage 42 fitted to the inside and outside, and the lubricity is improved by forcibly making lubricating oil enter into the bearing by the pump action by rotation of the divided cages 41 and 42 different in the outer diameter. A clearance 55 is formed between the inner periphery of the second divided cage 42 and an outer diameter surface of the inner race 21, and a width dimension in the radial direction of the clearance 55 is set to 2.0% or less of an inner race outer diameter, and the torque loss is reduced by controlling an entering quantity of the lubricating oil entering into the bearing.

Description

  The present invention relates to a deep groove ball bearing in which a ball is incorporated between an outer ring and an inner ring, and a bearing device using the deep groove ball bearing.

  As shown in FIG. 10, the rotation of the final drive gear 1 of the transmission is transmitted from the final driven gear 2 to the differential case 3 that supports the gear 2, and the rotation of the differential case 3 is transmitted from a pair of pinions 5 fixed to the pinion shaft 4. In the differential that is transmitted to the side gears 6a, 6b meshing therewith and transmitted to the left and right axles 7a, 7b that support the side gears 6a, 6b, the cylindrical portions 8a formed at both ends of the differential case 3, 8b is rotatably supported by a pair of bearings B supported by the housing 9.

  In the differential, since a helical gear is employed for the final driven gear 2 supported by the differential case 3, when the final driven gear 2 rotates, a thrust load is applied to the differential case 3.

  For this reason, it is necessary to use a bearing that can support both radial load and thrust load as the bearing B that supports the differential case 3.

  A tapered roller bearing is suitable for a bearing for supporting the differential case 3 because it has a large load capacity and can receive both a thrust load and a radial load. However, tapered roller bearings have a problem that loss torque is large and fuel consumption increases. In order to reduce fuel consumption, there are many cases where deep groove ball bearings with less loss torque are used.

  By the way, deep groove ball bearings are inferior in oil permeability (lubricity) compared to tapered roller bearings, and generate heat when used under high loads and high-speed rotations such as the above differentials and transmissions. It is easy and has a problem in durability.

  In order to solve such a problem, in the deep groove ball bearing described in Patent Document 1, a cage for holding a ball is divided into a first divided cage made of a synthetic resin molded product and the first divided cage. It is formed with a second divided cage that is fitted and integrated into the cage, and at the time of bearing rotation, due to the difference in peripheral speed based on the difference in diameter between the first divided cage and the second divided cage The pumping action is generated, and the lubricating action is improved by forcibly flowing the lubricating oil into the bearing by the pumping action.

JP 2011-21661 A

  By the way, in the deep groove ball bearing described in the above-mentioned Patent Document 1, since the supply of the lubricating oil into the bearing is due to the pump action, the amount of entry is large, and when the bearing is rotated, the lubricating oil is agitated by the balls and rotated greatly. The resistance becomes large, the torque loss is large, and there are still points to be improved in reducing the torque of the deep groove ball bearing.

  An object of the present invention is to reduce torque loss of a deep groove ball bearing excellent in lubricity.

  In order to solve the above problems, in the deep groove ball bearing according to the present invention, an outer ring having a raceway groove formed on the inner diameter surface, an inner ring having a raceway groove formed on the outer diameter surface, and a raceway groove of the outer ring, A ball assembled between the raceway grooves of the inner ring and a cage for holding the ball, the cage being a cylindrical first divided cage made of a synthetic resin molded product, and the first divided cage The second split cage is made of a synthetic resin and is inserted into the inner side of the first split cage, and the two split cages are provided on one axial side surface of the first split cage and the other axial side surface of the second split cage. A combined state in which notches are formed at intervals in the circumferential direction to form a circular pocket for holding a ball in a state in which the inner and outer portions are combined, and the first divided holder and the second divided holder form a circular pocket. Therefore, the split cages are not separated in the axial direction. In a deep groove ball bearing provided with a means, the radial width of the clearance formed between the inner diameter surface of the second split cage and the outer diameter surface of the inner ring is 2.0% or less of the outer diameter of the inner ring. In this case, a configuration is employed in which connecting means for engaging both the cages in the axial direction by engaging with each other is provided.

  Further, in the bearing device according to the present invention, in the bearing device in which a shaft provided with a helical gear is rotatably supported by a pair of rolling bearings partially immersed in an oil bath, the pair of rolling bearings is related to the present invention. The above-mentioned deep groove ball bearing is used.

  In the bearing device having the above configuration, when the shaft rotates, the ball revolves while rotating due to the relative rotation of the outer ring and the inner ring, and the cage also rotates due to the revolution. At this time, the cage has a configuration in which the second divided cage is incorporated in the first divided cage, and the peripheral speed varies depending on the diameter, so that a pump action occurs, and the lubricating oil is supplied by the pump action. It is fed into the bearing through a clearance formed between the inner diameter surface of the two-piece cage and the outer diameter surface of the inner ring.

  At this time, the radial width of the clearance formed between the inner diameter surface of the second split cage and the outer diameter surface of the inner ring is 2.0% or less of the outer diameter of the inner ring. The amount of the lubricating oil entering the shaft is controlled by the clearance, and the minimum necessary lubricating oil is supplied into the bearing. For this reason, since the agitation resistance of the lubricating oil in the bearing is small and the torque loss is also small, the shaft can be rotated smoothly, and the effect of reducing fuel consumption can be achieved.

  Here, the clearance may be formed between the cylindrical surface formed on the inner periphery of the second split cage and the outer diameter surface of the inner ring, or the inner diameter surface end of the second split cage. It may be formed between the inner diameter surface of the flange provided on the outer surface and the outer diameter surface of the inner ring. Furthermore, it may be formed between the small diameter end of the tapered surface provided on the inner periphery of the second split cage and the outer diameter surface of the inner ring.

  In the deep groove ball bearing according to the present invention, the height of the shoulder on one side of the outer ring raceway groove and the shoulder on the other side of the inner ring raceway groove is set to the height of the shoulder on the other side of the outer ring raceway groove and the shoulder on the one side of the inner ring raceway groove. By forming the clearance between the outer diameter surface of the lower shoulder on one side of the inner ring raceway groove and the inner diameter surface of the second split cage, the clearance of the ball to the higher shoulder is increased. It is possible to receive a relatively large thrust load due to its high shoulder, preventing climbing and obtaining a deep groove ball bearing that is extremely advantageous for incorporation in a bearing device where a tapered roller bearing was required. be able to.

In this case, if the height of the shoulder with a high height becomes larger than necessary, the ball cannot be assembled, and if it becomes too low, the ball rides up. For this reason, when the shoulder height of a high shoulder is H ₁ and the ball diameter is d, the ratio H ₁ / d of the shoulder height H ₁ to the ball diameter d is 0.25-0. A range of 50 is preferable.

  When assembling the above-mentioned deep groove ball bearings in the bearing device, the inner ring has a high shoulder located on the helical gear side, and the thrust load applied to the shaft by torque transmission to the helical gear is applied to the outer ring. The ball is prevented from being picked up by receiving it with a high shoulder on the inner ring.

  Here, if there is an error in the mounting direction of the deep groove ball bearing, the thrust load cannot be received, and the ball may ride on the shoulder with a low height. Therefore, if an identification display portion indicating the thrust load receiving side is provided on at least one of the first split cage and the second split cage, incorrect assembly can be prevented. The identification display unit may be configured such that the colors of the first divided holder and the second divided holder are different.

  In the deep groove ball bearing according to the present invention, as a connecting means, an inward engagement claw is provided between the pocket claws of the adjacent pockets of the first split cage, and the pocket claws of the adjacent pockets of the second split cage are between An engaging claw of the second divided holder is provided, and the engaging claw of the first divided holder is engaged with an engaging recess formed on the outer diameter surface of the second divided holder. It is possible to adopt a configuration in which the is engaged with an engaging recess formed on the inner diameter surface of the first split cage.

  In adopting the connecting means as described above, the number of the engagement portions of the engagement claw and the engagement recess is three or more, so that the first divided holder and the second divided holder are more reliably coupled. be able to.

  In addition, by setting the circumferential clearance formed between the engaging claw and the engaging recess larger than the circumferential pocket clearance formed between the ball and the pocket, a large moment load is applied and the ball is delayed. Even if the first split cage and the second split cage rotate relative to each other, the engaging claws do not come into contact with the opposite side surfaces in the circumferential direction of the engaging recess, and the engaging claws are damaged. It can be effective for prevention.

  Further, the first split retainer and the second split retainer are formed by making the axial clearance formed between the engaging claw and the engaging recess larger than the axial pocket clearance formed between the ball and the pocket. When the axial force in the direction separating from each other is applied, the inner surfaces of the pair of opposing pocket claws abut against the outer peripheral surface of the ball, and the engaging claws abut against the axial end surface of the engaging recess. Therefore, the effect of preventing damage to the engaging claws can be obtained.

  Since the deep groove ball bearing is lubricated with lubricating oil, the first split cage and the second split cage are preferably formed of a synthetic resin excellent in oil resistance. Examples of such a resin include polyamide 46 (PA46), polyamide 66 (PA66), and polyphenylene sulfide (PPS). Among these resins, polyphenylene sulfide (PPS) has excellent oil resistance compared to other resins, and therefore, considering the oil resistance, it is most preferable to use polyphenylene sulfide (PPS).

  In view of the price of the resin material, it is preferable to use polyamide 66 (PA66), which may be determined appropriately according to the type of the lubricating oil.

  As described above, in the deep groove ball bearing according to the present invention, the width dimension in the radial direction of the clearance formed between the inner diameter surface of the second split cage and the outer diameter surface of the inner ring is 2.0. % Or less, the minimum necessary amount of lubricating oil can be supplied into the bearing, the stirring resistance of the lubricating oil in the bearing can be reduced, and torque loss can be reduced.

  Further, in the bearing device according to the present invention, the shaft is supported by using the deep groove ball bearing, so that it is possible to improve the fuel efficiency.

Longitudinal front view showing an embodiment of a deep groove ball bearing according to the present invention Sectional drawing which expands and shows a part of FIG. The top view which shows a part of a 1st division | segmentation holder | retainer and a 2nd division | segmentation holder | retainer The top view which shows the combined state of the 1st division | segmentation holder | retainer shown in FIG. 3, and a 2nd division | segmentation holder | retainer Sectional view along line VV in FIG. Sectional view along line VI-VI in FIG. Sectional drawing which shows the other example of a holder | retainer Sectional drawing which shows another example of a holder | retainer Schematic showing an embodiment of a bearing device Cross-sectional view showing differential

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1 and FIG. 2, the deep groove ball bearing A incorporates a ball 31 between a raceway groove 12 formed on the inner diameter surface of the outer ring 11 and a raceway groove 22 provided on the outer diameter surface of the inner ring 21. The ball 31 is held by a cage 40.

  Of the pair of shoulders 13a and 13b formed on both sides of the raceway groove 12 of the outer ring 11, the height of the shoulder 13a located on one side of the raceway groove 12 is higher than the height of the shoulder 13b located on the other side. It has become. On the other hand, of the pair of shoulders 23a and 23b formed on both sides of the raceway groove 22 of the inner ring 21, the height of the shoulder 23b located on the other side of the raceway groove 22 is higher than the height of the shoulder 23a located on one side. It is high.

  Here, the shoulder heights of the low shoulders 13b and 23a are the same as the shoulders of the standard deep groove ball bearing.

  For convenience of explanation, the high shoulders 13a and 23b are referred to as thrust load side shoulders 13a and 23b, and the low shoulders 13b and 23a are referred to as thrust non-load side shoulders 13b and 23a.

Thrust load side of the shoulder 13a, the shoulder height of 23b as _{H 1,} when the spherical diameter of the ball 31 is d, the ratio _H 1 / d of the shoulder height _{H 1} relative to the spherical diameter d of the ball _{31, H} 1 / It is set as the range of d = 0.25-0.50.

  The cage 40 includes a first divided cage 41 and a second divided cage 42 fitted inside the first divided cage 41.

  As shown in FIG. 3, the first split holder 41 has a pair of opposed pocket claws 44 formed on the one side surface in the axial direction of the annular body 43 at equal intervals in the circumferential direction, It consists of a synthetic resin molded product provided with pockets 45 of a size larger than one half of the annular body 43, and the inner diameter of the annular body 43 is equal to the pitch circle diameter (PCD) of the balls 31 shown in FIG. The outer diameter of the outer ring 11 is within the range of the inner diameter of the shoulder 13a where the height of the outer ring 11 is high and the inner diameter of the shoulder 13b where the height of the outer ring 11 is low, and the outer ring 11 can be inserted into the bearing from the side of the shoulder 13b where the height is low. Has been.

  On the other hand, as shown in FIG. 3, the second split cage 42 has a pair of opposed pocket claws 49 formed on the other side surface in the axial direction of the annular body 48 at equal intervals in the circumferential direction. 2 is formed of a synthetic resin molded article provided with a pocket 50 having a size exceeding one half of the ring 48, and the outer diameter of the ring 48 is the pitch circle diameter of the ball 31 shown in FIG. It is substantially equal to (PCD), and the inner diameter is within the range of the outer diameter of the shoulder 23b having a high height of the inner ring 21 and the outer diameter of the shoulder 23a having a low height. The second split cage 42 can be inserted into the bearing from the low shoulder 23a side, and can be fitted inside the first split cage 41.

  As shown in FIGS. 4 and 5, a connecting means X is provided between the first divided holder 41 and the second divided holder 42 so as not to be separated in the axial direction in a fitted state in which the inner and outer parts are fitted. ing.

  The connecting means X is provided with an inward engagement claw 46 between the pocket claws 44 of the adjacent pockets 45 of the first divided holder 41, and on the inner surface of the annular body 43 on the same axis as the engagement claw 46. A groove-like engagement recess 47 is formed in the second partition holder 42, an outward engagement claw 51 is provided between the pocket claws 49 of the adjacent pockets 50 of the second divided holder 42, and the outer diameter surface of the annular body 48 is An engagement recess 52 is formed on the same axis as the engagement claw 51, and the engagement claw 46 of the first split holder 41 and the engagement recess 52 of the second split holder 42 are engaged, and the second split holding is performed. The first split holder 41 and the second split holder 42 are not separated in the axial direction by the engagement of the engaging claw 51 of the holder 42 and the engaging recess 47 of the first split holder 41. Yes.

  Here, since the 1st division | segmentation holder | retainer 41 and the 2nd division | segmentation holder | retainer 42 are exposed to the lubricating oil which lubricates a deep groove ball bearing, it is made to use the synthetic resin excellent in oil resistance. Examples of such a synthetic resin include polyamide 46 (PA46), polyamide 66 (PA66), and polyphenylene sulfide (PPS). These resins may be selected and used according to the type of lubricating oil.

  As shown in FIG. 2, the inner diameter side of the second split cage 42 is built up so that the radial thickness is larger than the radial thickness of the first split cage 41. 53 shows a thickened thickened portion, and the inner periphery of the thickened portion 53 is a cylindrical surface 54, and between the cylindrical surface 54 and the cylindrical outer diameter surface of the shoulder 23 a having a low height of the inner ring 21. A clearance 55 is formed.

C in FIG. 2 shows a radial width dimension of the clearance 55, the width dimension c is the outer diameter (outer diameter inner ring of the standard deep groove ball bearing) of the low profile shoulder 23a of the inner ring 21 D ₂ Of 2.0% or less.

  The deep groove ball bearing A shown in the embodiment has the above-described structure. When the deep groove ball bearing A is assembled, the inner ring 21 is inserted inside the outer ring 11, and the raceway groove 22 and the outer ring 11 of the inner ring 21 are inserted. A required number of balls 31 are assembled between the raceway grooves 12.

  At this time, the inner ring 21 is offset in the radial direction with respect to the outer ring 11, a part of the outer diameter surface of the inner ring 21 is brought into contact with a part of the inner diameter surface of the outer ring 11, and 180 degrees in the circumferential direction from the contact part. A crescent-shaped space is formed at a position deviated, and the ball 31 is assembled from one side of the space.

Upon incorporation of the balls 31, when the shoulder height H ₁ of the thrust load side of the shoulder 23b of the thrust load side of the shoulder 13a and the inner ring 21 of the outer ring 11 is higher than necessary, to inhibit the incorporation of the balls 31 However, in the embodiment, since the ratio H ₁ / d of the shoulder height H ₁ to the ball diameter d of the ball 31 does not exceed 0.50, the gap between the outer ring 11 and the inner ring 21 is The ball 31 can be reliably assembled.

  After the ball 31 is assembled, the center of the inner ring 21 is made to coincide with the center of the outer ring 11, and the balls 31 are arranged at equal intervals in the circumferential direction. The first divided holder 41 is inserted between the first divided holder 41 so that the balls 31 fit into the pockets 45 formed in the first divided holder 41.

  Further, the second split cage 42 is inserted between the outer ring 11 and the inner ring 21 from one side of the shoulder 23a on the thrust non-load side of the inner ring 21, and the ball 31 is placed in the pocket 50 formed in the second split cage 42. The second split holder 42 is fitted into the first split holder 41 by being inserted.

  As described above, the second divided holder 42 is fitted into the first divided holder 41 to form the divided holders 41 and 42 as shown in FIGS. 2, 4 and 5. The engaging claws 46 and 51 are engaged with the engaging recesses 47 and 52 provided in the other split cage, and the assembly of the deep groove ball bearing A is completed.

  FIG. 9 shows a bearing device that rotatably supports a shaft 57 that supports the helical gear 56 on the driven side using the deep groove ball bearing A shown in the embodiment. In this case, the deep groove ball bearing A is assembled such that the shoulder 23b on the load side of the inner ring 21 is located on the helical gear 56 side. The deep groove ball bearing A is assembled so that a part thereof is immersed in an oil bath.

  In the above bearing device, when rotation is transmitted from the drive side helical gear 58 to the driven side helical gear 56, a thrust force is applied to the shaft 57, and the thrust force is a thrust load side shoulder 23b of the inner ring 21 in the deep groove ball bearing A and the outer ring. 11 on the thrust load side shoulder 13a.

  At this time, a thrust force is also applied to the ball 31, and when the thrust load side shoulder 23b of the inner ring 21 and the thrust load side shoulder 13a of the outer ring 11 are lower than necessary, the ball 31 rides on the shoulders 13a, 23b, There is a possibility of damaging the edges of the shoulders 13a and 23b.

In the embodiment, since the ratio H ₁ / d of the shoulder height H ₁ to the ball diameter d of the ball 31 is set to 0.25 or more, the riding of the ball 31 can be reliably prevented.

  Here, when the shaft 57 rotates together with the driven-side helical gear 56, the inner ring 21 in the deep groove ball bearing A rotates relative to the outer ring 11, and the ball 31 revolves while rotating. Due to the revolution, the cage 40 also rotates. At this time, the retainer 40 has a configuration in which the second split retainer 42 is incorporated in the first split retainer 41, and the first split retainer 41 and the second split retainer 42 have different outer diameters. Since the peripheral speed varies depending on the difference in diameter, a pump action occurs. The pumping action causes the lubricating oil to be fed into the bearing from a clearance 55 formed between the inner diameter surface of the second split cage 42 and the outer diameter surface of the shoulder 23a of the inner ring 21.

  At this time, the width c in the radial direction of the clearance 55 is 2.0% or less of the outer diameter of the shoulder 23a of the inner ring 21, so that the lubricant entering the deep groove ball bearing A from the clearance 55 enters. The amount is controlled by the clearance 55 so that the minimum necessary amount of lubricating oil is supplied into the deep groove ball bearing A. For this reason, since the agitation resistance of the lubricating oil in the deep groove ball bearing A is small and the torque loss is also small, the shaft 57 can be smoothly rotated, and the effect of reducing fuel consumption can be obtained.

  Here, when the bearing device is assembled, if there is an error in the mounting direction of the deep groove ball bearing A, the thrust load may not be received and the balls 31 may ride on the low shoulders 13b and 23a. Therefore, in the embodiment, as shown in FIG. 1, the outer ring 11, the inner ring 21, the first divided holder 41 and the second divided holder 42 are made different in color, and the deep groove ball bearing A is incorporated from that color. The direction can be determined.

  In the deep groove ball bearing shown in the embodiment, a pair of opposed pocket claws 44 and 49 for embedding the ball 31 at the open ends of the pocket 45 of the first divided holder 41 and the pocket 50 of the second divided holder 42 are provided. The pair of opposed pocket claws 44 formed in the first divided holder 41 and the pair of opposed pocket claws 49 provided in the second divided holder 42 are combined to face in opposite directions. Since the first claws 41 and the second split cage 42 are not separated in the axial direction by engaging the engaging claws 46 and 51 with the engagement recesses 47 and 52, a large moment load is applied to the ball 31. Even if a delay or advance occurs, the retainer 40 does not fall off.

Here, as shown in FIG. 4, a clearance amount δ ₁ of the circumferential clearance 60 formed between the engaging claws 46 and 51 and the engaging recesses 47 and 52 is formed between the ball 31 and the pockets 45 and 50. By making the clearance larger than the clearance amount δ ₂ of the pocket clearance 61 in the circumferential direction, a large moment load is applied and the ball 31 is delayed and advanced, and the first split retainer 41 and the second split retainer 42 are relative to each other. Even if the claw rotates, the engaging claws 46 and 51 do not come into contact with the side surfaces opposed to each other in the circumferential direction of the engaging recesses 47 and 52, and it is possible to effectively prevent damage to the engaging claws 46 and 51. .

Further, as shown in FIGS. 4 and 5, a clearance amount δ ₃ of the axial clearance 62 formed between the engaging claws 46 and 51 and the engaging recesses 47 and 52 is formed between the ball 31 and the pockets 45 and 50. When the axial force in the direction away from the first divided holder 41 and the second divided holder 42 is applied to the first divided holder 41 and the second divided holder 42 by making the gap amount δ ₄ of the axial pocket gap to be increased, The inner surfaces of the pocket claws 44 and 49 abut against the outer peripheral surface of the ball 31, and the engagement claws 46 and 51 do not abut against the axial end surfaces of the engagement recesses 47 and 52. 51 can be effective in preventing damage.

  In the example shown in FIG. 2, a cylindrical surface 54 is formed on the inner periphery of the second split cage 42, and a clearance 55 is formed between the cylindrical surface 54 and the outer diameter surface of the shoulder 23 a of the inner ring 21. As shown in FIG. 5, a flange 70 may be provided at the end of the inner surface of the second split cage 42, and a clearance 55 may be formed between the inner surface of the flange 70 and the outer surface of the shoulder 23a of the inner ring 21.

  Further, as shown in FIG. 8, a tapered surface 71 is formed on the inner periphery of the thickened portion 53 of the second split cage 42, and between the small diameter end of the tapered surface 71 and the outer diameter surface of the shoulder 23 a of the inner ring 21. A clearance 55 may be formed.

  In the embodiment, the deep groove ball bearing in which the heights of the shoulders 13a and 13b of the outer ring 11 and the shoulders 23a and 23b of the inner ring 21 are different is shown, but the shoulders 13a and 13b of the outer ring 11 and the shoulders 23a and 23b of the inner ring 21 are shown. 4 and 5 is incorporated between the outer ring and the inner ring of the standard type deep groove ball bearing in which the heights of the inner ring are the same, so that the outer diameter surface of the inner ring and the second divided holder 42 are interposed. A clearance 55 may be formed.

11 outer ring 12 raceway groove 13a shoulder 13b shoulder 21 inner ring 22 raceway groove 23a shoulder 23b shoulder 31 ball 40 retainer 41 first divided retainer 42 second divided retainer 43 annular body 44 pocket claw 45 pocket 46 engagement claw 47 engagement Recess 48 Annular body 49 Pocket claw 50 Pocket 51 Engagement claw 52 Engagement recess 54 Cylindrical surface 55 Clearance 56 Helical gear 57 Shaft 60 Circumferential clearance 61 Peripheral pocket clearance 62 Axial clearance 70 Flange 71 Tapered surface A Deep groove ball bearing X connection means

Claims (14)

From an outer ring having a raceway groove formed on the inner diameter surface, an inner ring having a raceway groove formed on the outer diameter surface, a ball assembled between the raceway groove of the outer ring and the raceway groove of the inner ring, and a cage for holding the ball The cage is composed of a cylindrical first divided cage made of a synthetic resin molded product and a synthetic resin cylindrical second divided cage inserted inside the first divided cage. And a notch for forming a circular pocket for holding a ball in a state where both the split cages are combined inside and outside on one axial side surface of the first split cage and the other axial side surface of the second split cage. A connecting means is provided that is spaced apart in the circumferential direction, and in which the first divided holder and the second divided holder form a circular pocket, and the two divided holders are not separated in the axial direction. In deep groove ball bearings,
A deep groove ball bearing characterized in that the radial width dimension of the clearance formed between the inner diameter surface of the second split cage and the outer diameter surface of the inner ring is 2.0% or less of the inner ring outer diameter.   The deep groove ball bearing according to claim 1, wherein a cylindrical surface is provided on an inner periphery of the second split cage, and the clearance is formed between the cylindrical surface and an outer diameter surface of the inner ring.   The deep groove ball bearing according to claim 1, wherein a flange is provided at an inner diameter surface end of the second split cage, and the clearance is formed between the inner diameter surface of the flange and the outer diameter surface of the inner ring.   The deep groove ball bearing according to claim 1, wherein a tapered surface is provided on an inner periphery of the second split cage, and the clearance is formed between a small diameter end of the tapered surface and an outer diameter surface of the inner ring.   The height of the shoulder on one side of the outer ring raceway groove and the shoulder on the other side of the inner ring raceway groove is higher than the height of the shoulder on the other side of the outer ring raceway groove and one side of the inner ring raceway groove, The deep groove ball bearing according to any one of claims 1 to 4, wherein the clearance is formed between an outer diameter surface of a shoulder having a low height on one side and an inner diameter surface of the second split cage. When the shoulder height of the high shoulder is H ₁ and the ball diameter is d, the ratio H ₁ / d of the shoulder height H ₁ to the ball diameter d is 0.25 to 0.50. The deep groove ball bearing according to claim 5, which is a range.   The deep groove ball bearing according to claim 5 or 6, wherein at least one of the first split cage and the second split cage is provided with an identification display portion indicating a thrust load receiving side.   The deep groove ball bearing according to claim 7, wherein the identification display unit is based on a difference in color between the first divided cage and the second divided cage.   The connecting means has an inward engagement claw between the pocket claws of the adjacent pockets of the first divided holder, and an outward engagement claw between the pocket claws of the adjacent pockets of the second divided holder. Engaging the engaging claw of the first split cage with the engaging recess formed in the outer diameter surface of the second split cage, and engaging the engaging claw of the second split cage with the first split cage. The deep groove ball bearing according to any one of claims 1 to 8, wherein the deep groove ball bearing is configured to engage with an engaging recess formed on an inner diameter surface.   The deep groove ball bearing according to claim 9, wherein the number of engaging portions of the engaging claw and the engaging recess is three or more.   The deep groove ball bearing according to claim 9 or 10, wherein a circumferential clearance formed between the engaging claw and the engaging recess is larger than a circumferential pocket clearance formed between the ball and the pocket.   The deep groove ball bearing according to any one of claims 9 to 11, wherein an axial clearance formed between the engaging claw and the engaging recess is larger than an axial pocket clearance formed between the ball and the pocket. .   The deep groove ball bearing according to any one of claims 1 to 12, wherein the first divided cage and the second divided cage are made of one of polyamide 46, polyamide 66, and polyphenylene sulfide. In a bearing device in which a shaft provided with a helical gear is rotatably supported by a pair of rolling bearings partially immersed in an oil bath,
The bearing device, wherein the pair of rolling bearings comprises the deep groove ball bearing according to any one of claims 1 to 13.

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