JP2010001924A - Combination bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a combination bearing receiving a radial load, axial loads in both directions, and a moment load, achieving torque reduction and space saving, and allowing a preload gap to be easily adjusted. <P>SOLUTION: The combination bearing 10 is the back-to-back combination of a plurality of angular contact ball bearings 20 provided with an inner ring 21 having an inner ring raceway groove 21a on an outer peripheral surface, an outer ring 22 having an outer ring raceway groove 22a on an inner peripheral surface, a plurality of balls 23 arranged between the inner ring raceway groove 21a and the outer ring raceway groove 22a so as to freely roll, and a retainer 24 retaining the balls 23 in prescribed intervals along the circumferential direction. A cross sectional size ratio (B/H) between an axial direction cross section width B of the angular contact ball bearing 20 and a radial direction cross section height H is expressed as follows; 0.1<B/H<0.63, and an inner ring spacer 31 is disposed between the inner rings 21 of the angular contact ball bearings 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes, for example, industrial machines, robot joints and turning mechanisms, spindles of machine tools, rotary tables and spindle turning mechanisms, medical equipment, semiconductor / liquid crystal manufacturing apparatuses, optical and optoelectronic devices, etc. It is related with the combination bearing which supports.

  Usually, for example, a rotating table of a machine tool, a rotating mechanism unit such as a spindle turning unit of a machine tool, a drum rotating shaft of a printing press, or a rotation of a direct joint motor or a rotating mechanism unit that applies rotation to these parts. A cross roller bearing, a four-point contact ball bearing, a combined angular ball bearing, a combined tapered roller bearing, or the like is used for the support portion or the like so as to receive a radial load, an axial load in both directions, and a moment load. (For example, refer to Patent Document 1).

  In Patent Document 1, a combination angular contact ball bearing capable of receiving the above-described load and capable of reducing torque by two-point contact is intended to save space by specifying a narrower cross-sectional dimension than a standard size ball bearing. Has been devised.

  Further, in the conventional combination bearing, only the inner ring spacer or the inner ring spacer and the outer ring spacer are disposed between the two bearings (see, for example, Patent Documents 2 and 3), or the side surface of the angular ball bearing. In order to prevent deformation of the inner ring, an inner ring spacer that contacts the inner ring has been devised to define the outer diameter of the contact surface with the inner ring (see, for example, Patent Document 4).

For example, in the angular ball bearing 100 described in Patent Document 4, as shown in FIG. 12, the outer diameter Li of the contact surface 110a of the inner ring spacer 110 is the pitch circle diameter PCD of the balls 101 and the diameter DW of the balls 101. For the contact angle α of the ball 101,
Li ≦ PCD−DW · cosα
Is set to
JP 2006-105385 A JP 2004-60758 A JP 2001-107956 A JP 2007-146938 A

  By the way, when the narrow combination angular contact ball bearing described in Patent Document 1 is applied to a machine tool main shaft, a rotary table, and a main shaft turning mechanism, the inner ring 201 is attached with a nut (not shown) to improve rotational accuracy and rigidity. A preload as shown in FIG. 13 (in this case, a fixed position preload) is often applied, such as tightening. (It may be used up to the clearance without preloading. In this case, a predetermined clearance is provided on the outer ring mating surface side, not the inner ring mating surface.)

  Fine adjustment of the preload clearance δ (clearance between the combined bearings) is performed by first temporarily measuring the preload clearance of the combined bearing, and then either one of the combined bearings so that the required preload clearance is obtained. The inner ring end surface or the outer ring end surface of the inner ring is adjusted and polished by using a grinding machine. In this case, place the bearing in a heated oil bowl once, or heat and expand only the outer ring using a high frequency heater, etc., remove the ball via the outer ring counter bore, disassemble the bearing, and the inner ring and outer ring alone Set in a grinding machine, process to the specified dimensions, expand only the outer ring with a high-frequency heater again, assemble the bearing in the reverse order of disassembly, and finally inspect the combined axial clearance become.

  If the predetermined clearance is not obtained after the final inspection, it is necessary to disassemble the bearing again, which greatly increases the number of man-hours. Although it is possible in some cases to perform adjustment polishing while the bearing is assembled, polishing debris is mixed into the bearing during processing, and small scratches and indentations are made on the outer ring groove part, the inner ring groove part and the ball. In machine tool applications, high rotation accuracy is required, and when used at high speed rotation, even a minute damage tends to progress to a failure of the bearing in use.

  In addition, the spacers described in other patent documents 2 to 4 are used together with ball bearings having standard dimensions, and space saving cannot be achieved even when applied to narrow combination bearings.

  The present invention has been made in view of the above-described circumstances, and its purpose is to receive a radial load, an axial load in both directions, and a moment load, while being able to reduce torque and save space. An object of the present invention is to provide a combination bearing that can be easily adjusted.

The above object of the present invention is achieved by the following configurations.
(1) an inner ring having an inner ring raceway on the outer peripheral surface;
An outer ring having an outer ring raceway on the inner peripheral surface;
A plurality of rolling elements which are arranged to be freely rollable between the inner ring raceway and the outer ring raceway;
A cage that holds the rolling elements at a predetermined interval in the circumferential direction;
A combination bearing comprising a plurality of bearings each comprising:
The sectional dimension ratio (B / H) between the axial sectional width B and the radial sectional height H of each of the bearings is 0.1 <B / H <0.63,
A combination bearing, wherein a spacer is provided between at least one of the bearing rings between the inner rings and between the outer rings of the bearings.
(2) The spacer is an inner ring spacer arranged between the inner rings,
A pair of relief portions that form an outer peripheral surface having a smaller diameter than the outermost diameter DL1 of the inner ring spacer are provided on both end surfaces in the axial direction of the inner ring spacer.
The outer diameter DL2 of the outer peripheral surface of the escape portion is defined as dm as the pitch circle diameter of the rolling elements, and DW as the diameter of the rolling elements.
dm−DW ≧ DL2
The combined bearing as set forth in (1), wherein
(3) The combined bearing according to (2), wherein the outermost diameter DL1 of the inner ring spacer is set such that DI ≧ DL1 where the outer diameter of the inner ring is DI.
(4) The spacer is an outer ring spacer arranged between the outer rings,
A pair of relief portions that form an inner peripheral surface having a diameter larger than the innermost diameter DK1 of the outer ring spacer are provided on both end surfaces in the axial direction of the outer ring spacer.
The inner diameter DK2 of the inner peripheral surface of the escape portion is defined as dm as the pitch circle diameter of the rolling elements, and DW as the diameter of the rolling elements.
dm + DW ≤ DK2
The combined bearing according to any one of (1) to (3), wherein
(5) The combined bearing according to (4), wherein the outermost ring inner diameter DK1 of the outer ring spacer is set such that DE ≦ DK1 when the outer ring inner diameter is DE.

  According to the combined bearing of the present invention, each of the narrow widths in which the sectional dimension ratio (B / H) between the axial sectional width B and the radial sectional height H is 0.1 <B / H <0.63. In the bearing, a spacer is provided between at least one raceway between each inner ring and each outer ring of each bearing. For this reason, adjustment of the axial clearance including the preload clearance and change of the axial clearance by reviewing the specifications can be performed by adjusting the spacer width without disassembling each bearing. Moreover, even if a spacer is provided, the combined bearing can maintain the full width. Therefore, the radial load, the axial load in both directions, and the moment load are received, the torque can be reduced and the space can be saved, and the preload clearance can be easily adjusted.

  Further, a pair of relief portions that form an outer peripheral surface having a smaller diameter than the outermost diameter DL1 of the inner ring spacer are provided on both end surfaces in the axial direction of the inner ring spacer disposed between the inner rings. The outer diameter DL2 of the outer peripheral surface may be set to dm−DW ≧ DL2 where dm is the pitch circle diameter of the rolling elements and DW is the diameter of the rolling elements. That is, for example, in a ball bearing in which the rolling elements are balls, the outer diameter of the outer peripheral surface of the escape portion is smaller than the bottom of the inner ring raceway. As a result, the inner ring and inner ring spacer are not in contact with each other on the outer diameter side from the groove bottom, so when the inner ring is fixed, the axial tightening load is not applied to the outer diameter side from the groove bottom, so the inner ring does not buckle in the axial direction. In addition, the groove bottom does not deform in a distorted manner, the bearing rotation accuracy is deteriorated, and the preload is not easily increased or decreased when a preload is applied to the bearing, and the preload can be uniformly applied to each ball. As a result, the torque unevenness of the bearing hardly occurs, and the wear and damage of the bearing due to excessive load do not occur. Further, even when the rigidity of the narrow inner ring spacer is small or the surface accuracy is low, the adverse effect exerted during installation can be extremely reduced.

  Further, the outermost diameter DL1 of the inner ring spacer is set to DI ≧ DL1 when the outer diameter of the inner ring is DI, so that the inner ring spacer can be prevented from coming into edge contact with the inner diameter of the cage.

  Further, a pair of relief portions that form an inner peripheral surface having a diameter larger than the innermost diameter DK1 of the outer ring spacer are provided on both end surfaces in the axial direction of the outer ring spacer disposed between the outer rings. The inner diameter DK2 of the inner peripheral surface may be set to dm + DW ≦ DK2. That is, in the ball bearing in which the rolling elements are balls, the inner diameter of the inner peripheral surface of the relief portion is larger than the bottom of the outer ring raceway. As a result, the outer ring and the outer ring spacer are not in contact with each other on the inner diameter side from the groove bottom.Therefore, when the outer ring is fixed, the axial tightening load is not applied to the inner diameter side from the groove bottom, so the outer ring does not buckle in the axial direction. The bottom does not deform in a distorted manner, the bearing rotation accuracy is deteriorated and the preload is not easily increased or decreased when a preload is applied to the bearing, and the preload can be uniformly applied to each ball. As a result, the torque unevenness of the bearing hardly occurs, and the wear and damage of the bearing due to excessive load do not occur. Further, even when the rigidity of the narrow outer ring spacer is small or the surface accuracy is low, the adverse effect exerted during assembly can be extremely reduced.

  Furthermore, since the innermost inner diameter DK1 of the outer ring spacer is set to DE ≦ DK1 when the outer ring inner diameter is set to DE, it is possible to prevent the outer ring spacer from making edge contact with the outer diameter of the cage.

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

(First embodiment)
FIG. 1 is a sectional view showing a combination bearing according to a first embodiment of the present invention. The combination bearing 10 of the present embodiment is configured by arranging a pair of narrow angular ball bearings 20 in a rear combination, and can be applied to various rotation support portions as described in the background art.

  Each angular ball bearing 20 includes an inner ring 21 which is a race ring having an inner ring raceway groove 21a on an outer peripheral surface, an outer ring 22 which is a race ring having an outer ring raceway groove 22a on an inner peripheral face, an inner ring raceway groove 21a and an outer ring raceway groove. A plurality of balls 23 as rolling elements that are arranged to freely roll with a contact angle between 22a and 22a, and a cage 24 that holds the balls 23 at a predetermined interval in the circumferential direction. Each angular ball bearing 20 may further be provided with a seal. In addition, since each angular ball bearing 20 is arranged in a back surface combination, the extension line L of the contact angle of each ball 23 intersects on the radially outer side from the ball 23.

  A counter bore 22b is formed on the inner peripheral surface of the outer ring 22 with a groove shoulder dropped on one side in the axial direction with respect to the outer ring raceway groove 22a. A shoulder 22c is formed on the counter bore side. The cage 24 is a machined cage, has a cylindrical pocket 25, and is guided by an outer ring 22 by a shoulder 22 c of the outer ring 22. The cage 24 may be an inner ring guide as long as it does not interfere with an inner ring spacer 31 described later.

  A narrow inner ring spacer 31 is provided between the inner rings 21 of each angular ball bearing 20. As shown in FIGS. 1 and 2, a pair of relief portions 32 that form an outer peripheral surface having a smaller diameter than the outermost diameter DL <b> 1 of the inner ring spacer 31 are formed on both end surfaces in the axial direction of the inner ring spacer 31. . The outermost diameter DL1 of the inner ring spacer 31 is set to DI ≧ DL1 where the inner ring outer diameter is DI, and the outer diameter DL2 of the outer peripheral surface of each relief portion 32 is the pitch circle diameter of the balls 23. Where dm is the diameter of the ball 23 and DW is the diameter of the ball 23, dm−DW ≧ DL2. Further, the axial width ΔD of each relief portion 32 may be a slight amount such that a step is formed after polishing, and may be, for example, about 0.1 to 0.5 mm.

  The combined bearing 10, including the inner ring spacer 31, is configured such that the combined width dimension of the outer ring 22 and the combined width dimension of the inner ring 21 are the same. Each angular ball bearing 20 has a sectional dimension ratio (B / H) of an axial sectional width B and a radial sectional height H (= (outer ring outer diameter D−inner ring inner diameter d) / 2) (B / H). <0.63. B / H is theoretically B / H> 0, but in reality, B / H> 0.10, preferably in consideration of the design, selection, etc. of balls, cages, and seals to be used. B / H> 0.20, more preferably B / H> 0.30.

  Further, in the case of standard ball bearings determined by the International Organization for Standardization (ISO), those with a B / H of around 1.0 account for the majority. Therefore, if B / H <0.5 is set, two rows of narrow ball bearings can be arranged in a space in the width direction of about one row of standard ball bearings, thereby saving space. In the case of angular contact ball bearings, only one axial load can be received in one row and moment load cannot be received. However, by combining two or more rows, the axial load and moment load in both directions can be reduced. Load becomes possible. Further, since preload can be added, it is possible to increase the radial rigidity, the axial rigidity, the moment rigidity and the like as well as space saving. If B / H <0.25, four rows of narrow ball bearings can be disposed, and the rigidity can be further improved.

In the combined bearing 10 configured as described above, the inner ring spacer is maintained while maintaining the combined width dimension of each outer ring 22 and the combined width dimension of each inner ring 21 of a conventional narrow combined bearing having no spacer. 31 is provided. That is, the axial width B1 of the inner ring spacer 31 is set to be smaller than the maximum distance B2 of the shoulder portions 21b of both inner rings 21 facing the inner ring spacer 31. Therefore, the preload clearance can be adjusted by adjusting the width of the inner ring spacer 31 without disassembling each angular ball bearing 20 while maintaining the advantage of space saving.
In addition, since the axial width B1 of the inner ring spacer 31 is smaller than the maximum distance B2 of the shoulder portions 21b of the inner rings 21, the groove shoulder portion remains and may interfere with the raceway groove or narrow the raceway length. There is also no interference between the ball and the spacer.

  Moreover, since the outermost diameter DL1 of the inner ring spacer 31 is set to DI ≧ DL1, it is possible to prevent the inner ring spacer 31 from coming into edge contact with the cage inner diameter. Since the inner ring spacer 31 does not protrude from the outer diameter of the inner ring, the lubricant can easily circulate between both the bearings 20, and the lubrication life can be improved.

  Further, in the inner ring spacer 31 provided with the pair of relief portions 32, the outer diameter DL2 of the outer peripheral surface of the escape portion 32 is set to dm−DW ≧ DL2, that is, the outer diameter DL2 of the outer peripheral surface of the escape portion 32. Is smaller than the bottom of the inner ring raceway groove 21a. Thereby, since the inner ring 21 and the inner ring spacer 31 do not come into contact with each other on the outer diameter side from the groove bottom, when the inner ring 21 is fixed, the axial tightening load is not applied to the outer diameter side from the groove bottom. Therefore, the groove bottom does not deform in a distorted manner, the bearing rotation accuracy is deteriorated, and the preload is not easily increased or decreased when the bearing is preloaded, and the preload can be uniformly applied to the balls 23. As a result, the torque unevenness of the bearing hardly occurs, and the wear and damage of the bearing due to excessive load do not occur.

  In the combined bearing 10 combined with the narrow angular ball bearing 20 of the present embodiment, the component rigidity of the narrow inner ring spacer 31 is inevitably small. For this reason, it becomes easy to warp to the end surface flat part after the finish polishing of the end surface of the inner ring spacer 31. In particular, when the bearing becomes large (the inner diameter of the bearing is φ150 mm to 300 mm or more), it is difficult to obtain the processing accuracy of the narrow inner ring spacer 31. For example, in the case of the inner ring spacer 31 ′ having a rectangular cross section as shown in FIG. 3, there is a possibility that the axial tightening load is applied to the outer diameter side from the groove bottom and the groove bottom is deformed. is there.

In addition, if the outermost diameter is reduced to the outer diameter of the relief portion in advance without providing the relief portion, deformation of the groove bottom can be prevented, but since the radial rigidity decreases as an annulus, roundness is also reduced. Extremely worse. Such a tendency is likely to occur in a large bearing. For example, in FIG. 4, O-O'around moment of inertia of area I is I = bh ^3/12, in addition to b is small narrow, because proportional to the cube of the radial thickness h, The thickness in the radial direction is reduced, and the rigidity is significantly reduced.
Therefore, by using the inner ring spacer 31 having the relief portion 32 as in the present embodiment, even if the rigidity of the narrow inner ring spacer is small or the surface accuracy is low, the adverse effect on assembling is extremely reduced. Can do.

  Further, as shown in FIG. 5B, when the end surface is subjected to finish polishing, in the case of a shape having the relief portion 32, the radial width ΔW1 of the polished portion is narrowed, and the warp angle ( When α) is constant, the planar accuracy can be reduced (ΔBa> ΔBa ′) as compared with the case having no relief portion as shown in FIG. Therefore, when it is fixed together with the inner ring 21, the eccentric load on the bearing becomes smaller, and the inclination of the inner ring 21 can be suppressed.

(Second Embodiment)
Next, a combination bearing according to a second embodiment of the present invention will be described with reference to FIG. In addition, about an equivalent part to 1st Embodiment, the same or equivalent code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

  As shown in FIG. 6, in the present embodiment, unlike the first embodiment having the inner ring spacer 31, a narrow outer ring spacer 41 is provided between each outer ring 22 of each angular ball bearing 20. The axial width B1 of the outer ring spacer 41 is also smaller than the maximum distance B2 of the shoulder portions 22c of both outer rings 22 facing the outer ring spacer 41.

  Further, a pair of relief portions 42 that form an inner peripheral surface having a diameter larger than the innermost diameter DK <b> 1 of the outer ring spacer 41 are formed on both end surfaces in the axial direction of the outer ring spacer 41. The innermost diameter DK1 of the outer ring spacer 41 is set to DE ≦ DK1, where the inner diameter of the outer ring is DE, and the inner diameter DK2 of the inner peripheral surface of each escape portion 42 is the pitch circle diameter of the balls 23 dm. When the diameter of the ball 23 is DW, dm + DW ≦ DK2 is set. Further, the axial width ΔD of each relief portion 42 may be a slight amount such that a step is formed after polishing, for example, about 0.1 to 0.5 mm, as in the first embodiment. .

  Further, the extension line L of the contact angle of the ball 23 is in the end surface plane portion where the outer ring spacer 41 contacts the axial end surface of each outer ring 22 (within the range of ΔW2 in FIG. 6). It is desirable that the inner diameter DK2 of the inner peripheral surface is set to be smaller than the intersection of the extension line L of the contact angle and the end surface of the outer ring spacer 41. This is to enable backup when the load is applied to the bearing 20 from the ball 23 toward the outer ring 22. If the above condition is not satisfied, the bearing 20 is loaded only by the outer ring 22. When the rigidity is easily lowered and a large load is applied, the bearing 20 may be damaged.

  In the combined bearing 10 configured as described above, in the outer ring spacer 41 provided with the pair of escape portions 42, the inner diameter DK2 of the inner peripheral surface of the escape portion 42 is set to dm + DW ≦ DK2, that is, the escape portion. The inner diameter DK2 of the inner peripheral surface of 42 is larger than the bottom of the outer ring raceway groove 22a. As a result, the outer ring 22 and the outer ring spacer 41 are not in contact with each other on the inner diameter side from the groove bottom. Therefore, when the outer ring 22 is fixed, the axial tightening load is not applied to the inner diameter side from the groove bottom, so the outer ring 22 is seated in the axial direction. The groove bottom does not bend and the groove bottom is not deformed, the bearing rotation accuracy is deteriorated, and the preload is not easily increased or decreased when the bearing is preloaded, and the balls 23 can be uniformly loaded with preload. As a result, the torque unevenness of the bearing hardly occurs, and the wear and damage of the bearing due to excessive load do not occur. Moreover, even when the rigidity of the narrow outer ring spacer 41 is small or the surface accuracy is low, the adverse effect exerted during assembly can be extremely reduced.

Further, since the innermost diameter DK1 of the outer ring spacer 41 is set to DE ≦ DK1, it is possible to prevent the outer ring spacer 41 from coming into edge contact with the outer diameter of the cage. Further, since the outer ring spacer 41 does not protrude from the inner diameter of the outer ring, the lubricant can easily circulate between both the bearings 20, and the lubrication life can be improved.
Other configurations and operations are the same as those in the first embodiment. In this embodiment, the retainer 24 uses an inner ring guide type, but may be an outer ring guide type as long as it does not interfere with the outer ring spacer 41.

(Third embodiment)
Next, a combination bearing according to a third embodiment of the present invention will be described with reference to FIG. In addition, about an equivalent part to 1st Embodiment, the same or equivalent code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

As shown in FIG. 7, in contrast to the inner ring spacer 31 of the first embodiment in which a pair of relief portions 32 are provided on the outer diameter side, the inner ring spacer 31 of the present embodiment has a pair of other inner ring spacers on the inner diameter side. An escape portion 33 is provided. By configuring in this way, the radial width ΔW1 of the end surface plane portion of the inner ring spacer 31 can be further reduced, and the influence of the flatness of the inner ring spacer 31 on the accuracy of the combined bearing 10 can be suppressed. it can.
Other configurations and operations are the same as those in the first embodiment.

  Moreover, the other relief part of this embodiment is applicable also to the outer ring | wheel spacer of 2nd Embodiment. That is, as a modification of the present embodiment, as shown in FIG. 8, the outer ring spacer 41 has a pair of escape portions 42 on the inner diameter side and a pair of other escape portions 43 on the outer diameter side. Also in this case, the outer diameter of the outer peripheral surface of the pair of other relief portions 43 is such that the outer ring spacer 41 has a contact angle extension L and the outer ring spacer 41 so that the load applied to the bearing 20 can be backed up. It is desirable to set the diameter larger than the intersection with the end face. (The extension line L of the contact angle is within the range of ΔW2 in FIG. 8.)

(Fourth embodiment)
Next, a combination bearing according to a fourth embodiment of the present invention will be described with reference to FIG. In addition, about the part equivalent to 1st and 2nd embodiment, the same or equivalent code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

In the combination bearing 10 of the present embodiment, a narrow inner ring spacer 31 is provided between the inner rings 21 of each angular ball bearing 20, and a narrow outer ring spacer 41 is provided between the outer rings 22. For example, when only one of the inner ring spacer 31 and the outer ring spacer 41 is provided, if the spacer is excessively shaved during the clearance adjustment, the spacer needs to be remade and replaced. On the other hand, when both the inner ring spacer 31 and the outer ring spacer 41 are provided as described above, the outer ring spacer can be trimmed again when the inner ring spacer is narrowed too much and the width of the inner ring spacer becomes narrow. .
In addition, about another structure and effect | action, it is the same as that of the case of 1st and 2nd embodiment.

FIG. 10 is a cross-sectional view showing a combined bearing having an inner ring spacer and an outer ring spacer according to a modification of the present embodiment. In the above embodiment, a machined cage is used as a cage, but in this modification, a ball guide type crown type cage 24a (single-side ring structure) with a pocket 25a as a spherical surface is used. In the crown type cage 24a, the ring portion 26 is disposed on the axially outer side (counter bore side) of the combination bearing 10. As a result, the end face of the crown-shaped cage 24a does not protrude from the side surface in the axial direction facing the spacers 31 and 41 of the inner ring 21 and the outer ring 22, and handling of the bearing is easy, for example, when adjusting the clearance. It becomes.
When both the inner ring spacer 31 and the outer ring spacer 41 are provided as in the present embodiment, the axial sectional width B that satisfies the sectional dimension ratio (B / H) of the present invention is the angular ball bearing 20. The total dimension is 1/2 of the axial cross-sectional width and the axial width B1 of each spacer.

(Fifth embodiment)
Next, a combined bearing according to a fifth embodiment of the present invention will be described with reference to FIG. In addition, about an equivalent part to the said embodiment, the same or equivalent code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

  As shown in FIG. 11, in the present embodiment, a front combination bearing 10 is shown, and the contact angle of the ball 23 of each angular ball bearing 20 intersects on the radially inner side from the ball 23. That is, the counter bore 22b is formed on the inner circumferential surface of the outer ring 22 on the side facing the axial direction with respect to the outer ring raceway groove 22a, and the shoulder portion 22c is formed on the outer side in the axial direction with respect to the outer ring raceway groove 22a. The An inner ring spacer 31 is provided between the inner rings 21. The cage is not shown in the figure.

Also, in the case of front combination, an extension line L of the contact angle of the ball 23 is an end surface plane where the inner ring spacer 31 contacts the axial end surface of each inner ring 21 so that the load applied to the bearing 20 can be backed up. The outer diameter DL2 of the outer peripheral surface of each relief portion 32 is set larger than the intersection of the contact angle extension line L and the end surface of the inner ring spacer 31. It is desirable.
In addition, about another structure and effect | action, it is the same as that of the said embodiment.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
The bearing device of the present invention can be used for other than the application of the present embodiment, for example, a rotary mechanism part of a machine tool, a turning mechanism part of a robot, a rotary part such as a joint part or a drum of a printing machine, a direct motor rotation support part, etc. The same effect can be exhibited. Especially for rotary tables of machine tools, spindle turning mechanisms, direct motor rotation support parts, robot joints and turning mechanisms, it is necessary to achieve both space saving and high rigidity, and narrow in the axial direction. If this bearing is used, since the amount of expansion and contraction of the raceway ring due to the preload is large, the above-described effects are further improved.

  The combination bearing of the present invention is not limited to the angular ball bearing of the present embodiment, but may be a deep groove ball bearing or the like. Further, the number of rows of the combination bearings may be two or more rows as necessary, for example, a multi-row combination such as a 3-row combination or a 4-row combination. Furthermore, the present invention can also be applied to a double row ball bearing in which an inner ring spacer or an outer ring spacer is disposed between double row inner rings or outer rings.

It is sectional drawing which shows the combination bearing which made the double row angular contact ball bearing which concerns on 1st Embodiment of this invention the back combination. It is an expanded sectional view of the inner ring spacer of FIG. It is sectional drawing which shows the combined bearing which made the back row combination the angular contact ball bearing of 2 rows as a reference example. It is explanatory drawing for demonstrating the calculation method of the cross-sectional secondary moment of an inner ring | wheel spacer. It is sectional drawing for demonstrating the curvature after grind | polishing an inner ring | wheel spacer. It is sectional drawing which shows the combination bearing which made the back surface combination the angular contact ball bearing of 2 rows which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the combination bearing which made the double row angular contact ball bearing which concerns on 3rd Embodiment of this invention a back combination. It is sectional drawing which shows the combination bearing which made the back surface combination the angular contact ball bearing of 2 rows which concerns on the modification of 3rd Embodiment of this invention. It is sectional drawing which shows the combination bearing which used the double row angular contact ball bearing which concerns on 4th Embodiment of this invention as a back surface combination. It is sectional drawing which shows the combined bearing which made the back surface combination the angular contact ball bearing of 2 rows which concerns on the modification of 4th Embodiment of this invention. It is sectional drawing which shows the combination bearing which used as a front combination the angular contact ball bearing of 2 rows which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the angular ball bearing provided with the conventional inner ring | wheel spacer. It is sectional drawing for demonstrating the process of providing a preload to the combination bearing of a general back combination.

Explanation of symbols

10 Combination Bearing 20 Angular Contact Ball Bearing 21 Inner Ring (Raceway Ring)
22 Outer ring (Raceway)
23 balls (rolling elements)
24 Cage 31 Inner ring spacer 32 Escape part 41 Outer ring spacer 42 Escape part

Claims (5)

An inner ring having an inner ring raceway on the outer peripheral surface;
An outer ring having an outer ring raceway on the inner peripheral surface;
A plurality of rolling elements which are arranged to be freely rollable between the inner ring raceway and the outer ring raceway;
A cage that holds the rolling elements at a predetermined interval in the circumferential direction;
A combination bearing comprising a plurality of bearings each comprising:
The sectional dimension ratio (B / H) between the axial sectional width B and the radial sectional height H of each of the bearings is 0.1 <B / H <0.63,
A combination bearing, wherein a spacer is provided between at least one of the bearing rings between the inner rings and between the outer rings of the bearings. The spacer is an inner ring spacer arranged between the inner rings,
A pair of relief portions that form an outer peripheral surface having a smaller diameter than the outermost diameter DL1 of the inner ring spacer are provided on both end surfaces in the axial direction of the inner ring spacer.
The outer diameter DL2 of the outer peripheral surface of the escape portion is defined as dm as the pitch circle diameter of the rolling elements, and DW as the diameter of the rolling elements.
dm−DW ≧ DL2
The combined bearing according to claim 1, wherein   3. The combined bearing according to claim 2, wherein the outermost diameter DL1 of the inner ring spacer is set such that DI ≧ DL1 when the outer diameter of the inner ring is DI. The spacer is an outer ring spacer arranged between the outer rings,
A pair of relief portions that form an inner peripheral surface having a diameter larger than the innermost diameter DK1 of the outer ring spacer are provided on both end surfaces in the axial direction of the outer ring spacer.
The inner diameter DK2 of the inner peripheral surface of the escape portion is defined as dm as the pitch circle diameter of the rolling elements, and DW as the diameter of the rolling elements.
dm + DW ≤ DK2
The combination bearing according to any one of claims 1 to 3, wherein   5. The combined bearing according to claim 4, wherein an outermost inner diameter DK <b> 1 of the outer ring spacer is set to satisfy DE ≦ DK <b> 1 when the outer ring inner diameter is DE.

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