JP5593768B2 - Bearing device - Google Patents

Description

  The present invention relates to a bearing device, and more particularly, to a bearing device that is used in a joint portion of a robot arm or a speed reducer to achieve a reduction in torque and a reduction in size.

  For example, a cross roller bearing, a four-point contact ball bearing, an angular ball bearing, or the like is used for the joint portion of the robot arm. The cross roller bearing has a structure in which the rollers are alternately rotated at an angle of 90 degrees and can receive a moment load. However, there is a problem that the contact surface is greatly worn and the rotational torque is large. For this reason, from the viewpoint of reducing torque, it is desirable to use a four-point contact ball bearing or an angular ball bearing in which the rolling elements are balls.

  In addition, when a rolling bearing used in a robot is composed of two parts, either an outer ring or an inner ring, the outer ring retainer or inner ring retainer is bolted to the joint or the rotating shaft. Separated from each other by preloading by joining two parts (for example, see Patent Document 1), by extending one part to the end of the other part and crimping the end of one part A device has been devised that disables preload adjustment by the user (see, for example, Patent Document 2).

  Furthermore, a wheel bearing device has been devised in which the inner rings are coupled by swinging and caulking the ends of the hub wheels and coupled to each other (see, for example, Patent Document 3).

JP 2007-192249 A JP 2002-235755 A JP 2007-24131 A

  By the way, in the rolling bearing described in Patent Document 1, an outer ring presser and an inner ring presser for joining two parts of the divided outer ring or inner ring are required, and a space is required in the axial direction. Also, in the rolling bearing described in Patent Document 2, since the caulking portion is located on the outer side in the axial direction of the race, the width dimension becomes large in order to arrange the peripheral parts of the robot arm so as not to interfere with each other. There is also a problem that handling is inconvenient.

  Further, in the wheel bearing device described in Patent Document 3, a notch portion is provided in the inner ring so that the caulking portion of the hub ring does not protrude from the end surface in the axial direction of the inner ring. The end face is inside the inner ring end face with the inner ring fitted, and the caulking strength may be low. Further, the inner ring and the hub ring constituting the inner ring raceway surface are formed in completely different shapes.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bearing device that achieves a reduction in torque and a reduction in size.

The above object of the present invention can be achieved by the following constitution.
(1) An outer ring member having an outer ring raceway surface on an inner peripheral surface, a pair of inner ring members each having an inner ring raceway surface on an outer peripheral surface, and a plurality of balls respectively disposed between the outer ring member and the inner ring member A ball bearing comprising:
A sleeve fitted and fixed to the pair of inner ring members;
A bearing device comprising:
The inner ring member is restrained by a caulking portion formed by plastic deformation of the sleeve in the axial direction toward the radially outer side, so that the pair of inner ring members are coupled and fixed to the sleeve. , A preload is applied to the ball bearing ,
Groove portions are respectively formed on the inner peripheral surfaces of the pair of inner ring members facing both end portions of the sleeve,
In the groove portion of the one inner ring member, a convex portion formed at the axial end portion of the sleeve is fitted,
The groove portion of the other inner ring member is suppressed by the caulking portion,
The bearing device is characterized in that the one inner ring member is fitted to the sleeve by a fit, and the other inner ring member is fitted to the sleeve by a clearance fit .
(2) The bearing device according to (1), wherein the caulking portion formed on the sleeve is positioned inside an end surface in the axial direction of the inner ring member.
(3) The bearing device according to (2), wherein the caulking portion formed on the sleeve is formed by plastically deforming a portion located outside the end surface in the axial direction of the inner ring member.
( 4 ) The outer ring member is provided with an attachment hole for attaching one member that rotates relative to the outer ring member,
The bearing device according to any one of (1) to ( 3 ), wherein the sleeve is provided with another mounting hole for mounting the other member that rotates relative to the sleeve.
( 5 ) In the ball bearing, the outer ring has a double row outer ring raceway surface, and the plurality of balls are double row between each outer ring raceway surface of the outer ring member and each inner ring raceway surface of the inner ring member. The bearing device according to any one of (1) to ( 4 ), wherein the bearing device is a double-row angular ball bearing having a rear combination.
( 6 ) The ball bearing is a four-point contact ball bearing in which the plurality of balls are in contact with two locations on the outer ring raceway surface of the outer ring and each inner ring raceway surface of the pair of inner ring members (1). The bearing device according to any one of ( 4 ) to ( 4 ).

  According to the bearing device of the present invention, by using a ball bearing, the contact surface becomes smaller than that of a conventional cross roller bearing, wear is reduced, and the torque is reduced. Etc. can be used suitably. In addition, the inner ring is restrained by a caulking portion formed by plastically deforming the axial end portion of the sleeve radially outward, so that the pair of inner ring members are coupled and fixed to the sleeve, and the ball Preload is applied to the bearing. As a result, the pair of inner ring members and the sleeve can be coupled and fixed without providing an inner ring retainer or the like, thereby achieving compactness. Further, the preload adjustment can be performed when assembling the ball bearing and the sleeve, and it is not necessary for the manufacturer using the bearing device to perform complicated preload adjustment.

1 is a longitudinal sectional view of a bearing device according to a first embodiment of the present invention. (A) is a principal part enlarged view which shows the state before crimping the sleeve shown in FIG. 1, (b) is a principal part enlarged view which shows the state after crimping. It is a longitudinal cross-sectional view of the bearing apparatus which concerns on 2nd Embodiment of this invention. (A) is a principal part enlarged view which shows the state before crimping the sleeve shown in FIG. 1, (b) is a principal part enlarged view which shows the state after crimping. It is a longitudinal cross-sectional view of the bearing apparatus which concerns on the modification of 2nd Embodiment of this invention.

  Hereinafter, a bearing device according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a longitudinal sectional view of a bearing device applied to a joint portion of a robot arm according to a first embodiment of the present invention. As shown in FIG. 1, the bearing device 10 includes a double-row angular ball bearing 11 and a sleeve 20. The double-row angular ball bearing 11 includes a single outer ring (outer ring member) 12 having double-row outer ring raceway surfaces 12a and 12a on the inner peripheral surface, and a pair of inner rings (inner ring raceways 13a and 14a on the outer peripheral surface). Inner ring members) 13, 14 and a plurality of outer ring raceway surfaces 12a, 12a of the outer ring 12 and inner ring raceway surfaces 13a, 14a of the inner rings 13, 14 are arranged in a plurality of rows with a contact angle. The ball 15 and the cage 16 that holds the ball 15 in the circumferential direction at a predetermined interval are provided, and are arranged in a back surface combination.

  The outer ring 12, the inner rings 13, 14, and the balls 15 are usually preferably made of bearing steel (for example, SUJ2), and stainless steel (for example, SUS440C) is preferably used when used in an atmosphere susceptible to rust. . Further, depending on the application, the outer ring 12 and the inner rings 13, 14 can be made of stainless steel, and the balls 15 filled with grease can be used as bearing steel.

  The cage 16 is a resin-made cage having high heat resistance, and in particular, polyamide 66 blended with glass fiber is preferably used.

  In addition, a pair of non-contact type seal members 17 are attached to both sides of the outer ring 12 in the axial direction, and seals the grease sealed in the bearing space. Thereby, it becomes the thing excellent in the surface of maintenance, and a torque can be restrained low by using the non-contact-type seal member 17. FIG. Although the grease used in the bearing space is not particularly limited, for example, it is excellent in durability and fretting wear by being composed of synthetic oil and urea-based thickener.

  The sleeve 20 is made of a material such as S25C, S45C, SUS440, and has an axial width substantially equal to the axial width of the double-row angular contact ball bearing 11, and is fitted and fixed to the pair of inner rings 13 and 14 so that the shaft portion is fixed. Configure. An annular end 20a extending from the axial end surface of the sleeve 20 in the axial direction and extending from the outer peripheral surface is formed at one axial end of the sleeve 20 (see FIG. 2A). Further, an annular convex portion 20 b extending outward in the radial direction is formed at the other axial end portion of the outer peripheral surface of the sleeve 20.

  A groove portion 14b is formed on the inner peripheral surface of the inner ring 14 at a position facing one axial end portion of the sleeve 20, and the inner peripheral surface of the inner ring 13 is also positioned at a position facing the other axial end portion of the sleeve 20. A groove 13b is formed.

The inner ring 13 is fitted to the sleeve 20 by a snug fit, and the annular projection 20b of the sleeve 20 is fitted into the groove 13b of the inner ring, whereby the inner ring 13 is positioned in the axial direction with respect to the sleeve 20. Then, after the inner ring 13 is fitted to the sleeve 20, as shown in FIG. 2A, the inner ring 14 is fitted to the sleeve 20 by clearance fitting, and the pressing die 30 having the processed surface portion 30a is inserted from the axial direction into the sleeve 20. Press on (flat press). Further, as shown in FIG. 2B, the pressing die 30 is pressed until the pressing surface portion 30b of the pressing die 30 contacts the axial end surface of the inner ring 14, and the annular end portion 20a is directed radially outward by the processing surface portion 30a. Thus, it is plastically deformed to become a caulking portion 20c, and the inner ring 14 is suppressed. As a result, the pair of inner rings 13, 14 are sandwiched between the annular convex portion 20 b and the caulking portion 20 c so as to be coupled and fixed to the sleeve 20, and a preload is applied to the double row angular ball bearing 11.
The reason why the inner ring 14 is fitted to the sleeve 20 by clearance fitting is that when the inner ring 14 is fitted to the sleeve 20 by tight fitting and the annular end portion 20a is plastically deformed, the stress on the inner ring raceway surface 14a increases. This is because there is a possibility of causing early peeling. For this reason, in this embodiment, the inner diameters of the pair of inner rings 13 and 14 are made uniform, and the shaft diameter of the sleeve 20 at the portion facing the inner ring 14 is set slightly smaller than the shaft diameter at the portion facing the inner ring 13. doing.
Moreover, it is preferable that the pressing die 30 is designed so that an appropriate preload is applied to the double-row angular ball bearing 11 when the holding surface portion 30b comes into contact with the axial end surface of the inner ring 14.

  Since the caulking portion 20c formed on the sleeve 20 is located inside the axial end surface of the inner ring 14, the caulking portion 20c can be prevented from interfering with peripheral parts such as a robot arm. On the other hand, the annular end 20a before the plastic deformation is positioned outside the axial end surface of the inner ring 14 when the sleeve 20 is fitted, so that the caulked portion 20c is firmly attached to the groove 14b when plastically deformed. This is for abutting and fixing.

  A plurality of mounting holes 12c for inserting fasteners (not shown) such as bolts are provided in the circumferential direction in order to attach one member (not shown) that rotates relative to the flange portion 12b of the outer ring 12. They are spaced apart and provided at a predetermined interval. The sleeve 20 is also provided with a plurality of other mounting holes 20d for inserting fasteners (not shown) such as bolts in order to attach the other member (not shown) that relatively rotates. The mounting hole 12c and the other mounting hole 20d may be screw holes or holes in which no screw is formed. The one and other members that rotate relative to each other include a robot arm, a gear, a motor, a pulley, a speed reducer, a toothed belt mechanism, and the like.

  As described above, according to the bearing device 10 of the present invention, the use of the double-row angular ball bearing 11 makes the contact surface smaller than the conventional cross roller bearing, reduces wear, and reduces torque. Therefore, it can be suitably used for a joint part of a robot arm, a reduction gear, or the like. Further, the inner ring 14 is restrained by the caulking portion 20c formed by plastically deforming the axial end portion of the sleeve 20 radially outward, so that the pair of inner rings 13 and 14 are coupled to the sleeve 20. In addition to being fixed, a preload is applied to the double-row angular contact ball bearing 11. Thereby, a pair of inner ring | wheels 13 and 14 and the sleeve 20 can be couple | bonded and fixed without providing an inner ring | wheel holding | suppressing etc., and compactization is achieved. Further, the preload adjustment can be performed when the double row angular ball bearing 11 and the sleeve 20 are assembled, and it is not necessary for the manufacturer using the bearing device 10 to perform complicated preload adjustment.

  Further, since the caulking portion 20c formed on the sleeve 20 is positioned inside the axial end surface of the inner ring 14, the caulking portion 20c can be prevented from interfering with peripheral parts of the robot arm.

  Further, the caulking portion 20c formed on the sleeve 20 is formed by plastically deforming the annular end portion 20a located outside the end surface in the axial direction of the inner ring 14, so that the caulking portion 20c is grooved when plastically deformed. 14b can be firmly abutted and fixed.

  In addition, groove portions 13b and 14b are formed on the inner peripheral surfaces of the pair of inner rings 13 and 14 facing both ends of the sleeve 20, respectively. The groove portion 13b of one inner ring 13 has an axial direction of the sleeve 20. An annular convex portion 20b formed at one end is fitted, the groove portion 14b of the other inner ring 14 is held down by a caulking portion 20c, and one inner ring 13 is fitted to the sleeve 20 by an interference fit, The inner ring 14 is fitted to the sleeve 20 by a clearance fit. As a result, the pair of inner rings 13 and 14 can be firmly coupled and fixed to the sleeve 20, and the occurrence of early separation of the inner ring raceway surface 14a due to caulking can be suppressed.

  The outer ring 12 is provided with an attachment hole 12c for attaching one member that rotates relative to the outer ring 12, and the sleeve 20 is provided with another attachment hole 20d for attaching the other member that rotates relative to the outer ring 12. One or the other member that rotates relative to each other can be firmly fixed without increasing the number of points.

(Second Embodiment)
FIG. 3 is a longitudinal sectional view of a bearing device applied to a joint portion of a robot arm according to a second embodiment of the present invention. As shown in FIG. 3, the bearing device 40 includes a four-point contact ball bearing 41 and a sleeve 50. The four-point contact ball bearing 41 has an outer ring (outer ring member) 42 having an outer ring raceway surface 42a on the inner peripheral surface and inner ring raceway surfaces 43a and 44a on the outer peripheral surface, respectively, and a pair of divided inner rings divided in the axial direction. (Inner ring members) 43, 44, and arranged between the outer ring raceway surface 42a and the inner ring raceway surfaces 43a, 44a, and in four places in total, two places on the outer ring raceway surface 12a and one place each on the inner ring raceway surfaces 43a, 44a. A plurality of balls 45 that come into contact with each other and a holder 46 that holds the balls 45 in the circumferential direction at predetermined intervals. The cross sections of the raceway surfaces of the outer ring 42 and the divided inner rings 43 and 44 are two arcs (so-called gothic arches) having the same radius of curvature. The four-point contact ball bearing 41 can receive a radial load, an axial load in both directions, and a moment load with a single bearing, and can save space.

  The outer ring 42, the divided inner rings 43 and 44, and the balls 45 are usually preferably made of bearing steel (for example, SUJ2), and stainless steel (for example, SUS440C) is preferably used when used in an atmosphere that tends to rust. The Further, depending on the application, the outer ring 42 and the divided inner rings 43 and 44 may be made of stainless steel, and the balls 45 filled with grease may be used as bearing steel to be used in combination.

  The cage 46 is a cage made of a copper alloy or a resin having high heat resistance, and in particular, a polyamide resin and a phenol resin are preferably used.

  A pair of non-contact type seal members 47 are attached to both sides of the outer ring 42 in the axial direction, and seals the grease sealed in the bearing space. Thereby, it becomes excellent in terms of maintenance, and the torque can be kept low by using the non-contact type seal member 47. Although the grease used in the bearing space is not particularly limited, for example, it is excellent in durability and fretting wear by being composed of synthetic oil and urea-based thickener.

  The sleeve 50 is made of a material such as S25C, S45C, or SUS440, and has an axial width substantially equal to the axial width of the four-point contact ball bearing 41. The sleeve 50 is fitted into and fixed to the pair of split inner rings 43 and 44. Configure. The sleeve 50 has the same configuration as that of the first embodiment, and an end portion in the axial direction of the sleeve 50 has an annular end portion extending from the axial end surface of the sleeve 50 in the axial direction and continuing from the outer peripheral surface. 50a is formed (see FIG. 4A), and an annular convex portion 50b extending outward in the radial direction is formed at the other axial end portion of the outer peripheral surface of the sleeve 50.

  Further, a groove 44b is formed on the inner peripheral surface of the split inner ring 44 at a position facing one end in the axial direction of the sleeve 50, and the other end in the axial direction of the sleeve 50 is also formed on the inner peripheral surface of the split inner ring 43. Grooves 43b are formed at the opposing positions.

The split inner ring 43 is fitted to the sleeve 50 by a snug fit, and the annular convex portion 50b of the sleeve 50 is fitted into the groove 43b of the split inner ring, whereby the split inner ring 43 is positioned in the axial direction with respect to the sleeve 50. Then, after the divided inner ring 43 is fitted to the sleeve 50, the divided inner ring 44 is fitted to the sleeve 50 by a clearance fit, and the pressing die 30 having the processed surface portion 30a is moved from the axial direction to the sleeve 50 as in the first embodiment. Press (flat press). Further, as shown in FIG. 4B, the pressing die 30 is pressed until the pressing surface portion 30b of the pressing die 30 abuts against the axial end surface of the divided inner ring 44, and the annular end portion 50a is radially outwardly formed by the processing surface portion 30a. Then, it is plastically deformed to become a caulking portion 50c, and the divided inner ring 44 is suppressed. As a result, the pair of split inner rings 43, 44 are sandwiched between the annular convex portion 50b and the caulking portion 50c and coupled and fixed to the sleeve 50, and a preload is applied to the four-point contact ball bearing 41.
The reason why the split inner ring 44 is fitted to the sleeve 50 by clearance fit is that when the split inner ring 44 is fitted to the sleeve 50 by tight fit and the annular end portion 50a is plastically deformed, the stress on the inner ring raceway surface 44a is increased. This is because it becomes high and may cause early peeling. Therefore, in this embodiment, the inner diameters of the split inner rings 43 and 44 are uniform, and the shaft diameter of the sleeve 50 at the portion facing the split inner ring 44 is slightly smaller than the shaft diameter of the portion facing the split inner ring 43. It is set.
Moreover, it is preferable that the pressing die 30 is designed so that an appropriate preload is applied to the double-row angular contact ball bearing 11 when the holding surface portion 30b contacts the axial end surface of the split inner ring 44.

  Since the caulking portion 50c formed on the sleeve 50 is located on the inner side of the axial end surface of the divided inner ring 44, the caulking portion 50c can be prevented from interfering with peripheral parts of the robot arm. On the other hand, the annular end portion 50a before plastic deformation is positioned outside the end surface in the axial direction of the split inner ring 44 when the sleeve 50 is fitted. The caulked portion 50c is firmly attached to the groove portion 44b when plastically deformed. This is to fix it.

  A plurality of attachment holes 42c for inserting fasteners (not shown) such as bolts are provided in the circumferential direction in order to attach one member (not shown) that rotates relative to the flange portion 42b of the outer ring 42. They are spaced apart and provided at a predetermined interval. The sleeve 50 is also provided with a plurality of other mounting holes 50d for inserting fasteners (not shown) such as bolts in order to attach the other member (not shown) that relatively rotates. The mounting hole 42c and the other mounting hole 50d may be screw holes or holes in which no screw is formed. The one member and the other member that rotate relative to each other are a robot arm, a gear, a motor, a pulley, a speed reducer, a toothed belt mechanism, and the like. The shape of the mounting hole 50d may be a shape that accommodates the head of the bolt as shown in FIG.

  As described above, according to the bearing device 40 of the present invention, the use of the four-point contact ball bearing 41 makes the contact surface smaller than the conventional cross roller bearing, reduces wear, and reduces torque. Therefore, it can be suitably used for a joint part of a robot arm or a speed reducer. Further, the split inner ring 44 is restrained by the caulking portion 50c formed by plastic deformation of the axial end portion of the sleeve 50 toward the radially outer side, so that the pair of split inner rings 43, 44 are connected to the sleeve 50. And a preload is applied to the four-point contact ball bearing 41. As a result, the pair of split inner rings 43 and 44 and the sleeve 50 can be coupled and fixed without providing an inner ring retainer or the like, thereby achieving compactness. Further, the preload adjustment can be performed when the four-point contact ball bearing 41 and the sleeve 50 are assembled, and it is not necessary for the manufacturer using the bearing device 40 to perform complicated preload adjustment.

  Further, since the caulking portion 50c formed on the sleeve 50 is positioned inside the axial end surface of the divided inner ring 44, the caulking portion 50c can be prevented from interfering with peripheral parts such as a robot arm.

  Further, the caulking portion 50c formed on the sleeve 50 is formed by plastically deforming the annular end portion 50a positioned outside the axial end surface of the divided inner ring 44. Therefore, when the caulking portion 50c is plastically deformed, the caulking portion 50c is formed. It can be firmly abutted against the groove 44b and fixed.

  In addition, grooves 43b and 44b are formed on the inner peripheral surfaces of the pair of split inner rings 43 and 44 facing both ends of the sleeve 50, respectively. An annular convex portion 50b formed at one end in the axial direction is fitted, the groove 44b of the other divided inner ring 44 is held down by a caulking portion 50c, and one divided inner ring 43 is fitted with the sleeve 50 by an interference fit. The other split inner ring 44 is fitted to the sleeve 50 by a clearance fit. Accordingly, the pair of split inner rings 43 and 44 can be firmly coupled and fixed to the sleeve 50, and the occurrence of early separation of the inner ring raceway surface 44a due to caulking can be suppressed.

  In addition, the outer ring 42 is provided with an attachment hole 42c for attaching one member that relatively rotates, and the sleeve 50 is provided with another attachment hole 50d for attaching the other member that relatively rotates. One or the other member that rotates relative to each other can be firmly fixed without increasing the number of points.

  In the present embodiment, the four-point contact ball bearing 41 has been described, but a three-point contact ball bearing may be used as long as the inner ring is constituted by a pair of split inner rings.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

DESCRIPTION OF SYMBOLS 10 Bearing apparatus 11 Double row angular contact ball bearings 12, 42 Outer ring (outer ring member)
12a, 42a Outer ring raceway surface 13, 14 Inner ring (inner ring member)
13a, 14a, 43a, 44a Inner ring raceway surface 15, 45 Ball 20, 50 Sleeve 20b, 50b Annular convex part 20c, 50c Caulking part 41 Four-point contact ball bearing 43, 44 Split inner ring (inner ring member)

Claims (6)

An outer ring member having an outer ring raceway surface on an inner peripheral surface, a pair of inner ring members each having an inner ring raceway surface on an outer peripheral surface, and a plurality of balls respectively disposed between the outer ring member and the inner ring member. Ball bearings,
A sleeve fitted and fixed to the pair of inner ring members;
A bearing device comprising:
The pair of inner ring members are coupled and fixed to the sleeve by the inner ring member being restrained by a caulking portion formed by plastic deformation of the axial end of the sleeve toward the radially outer side. A preload is applied to the ball bearing ,
Groove portions are respectively formed on the inner peripheral surfaces of the pair of inner ring members facing both end portions of the sleeve,
In the groove portion of the one inner ring member, a convex portion formed at the axial end portion of the sleeve is fitted,
The groove portion of the other inner ring member is suppressed by the caulking portion,
The bearing device is characterized in that the one inner ring member is fitted to the sleeve by a fit, and the other inner ring member is fitted to the sleeve by a clearance fit .   2. The bearing device according to claim 1, wherein the caulking portion formed on the sleeve is positioned on an inner side than an axial end surface of the inner ring member.   The bearing device according to claim 2, wherein the caulking portion formed on the sleeve is formed by plastically deforming a portion located outside an end surface in the axial direction of the inner ring member. The outer ring member is provided with a mounting hole for mounting one of the relatively rotating members,
It said sleeve bearing device according to any one of claims 1 to 3, characterized in that another mounting holes for attaching the other member to rotate relative is provided. In the ball bearing, the outer ring has a double row outer ring raceway surface, and the plurality of balls are arranged in a double row between each outer ring raceway surface of the outer ring member and each inner ring raceway surface of the inner ring member. The bearing device according to any one of claims 1 to 4 , wherein the bearing device is a double-row angular ball bearing of a rear combination. The ball bearing according to claim 1-4, wherein the plurality of balls are four-point contact ball bearing in contact with each inner ring raceway surface of the two locations and the pair of inner ring member of the outer ring raceway surface of the outer ring A bearing device according to any one of the above.

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