JP2012117567A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device which can maintain rigidity of bearing and improve rotation accuracy of the bearing used in inner ring rotation, while surely preventing creeping.SOLUTION: The bearing device includes a rolling bearing 10 in which an inner ring is out-fitted to a swivel base 32 which is a shaft, an outer ring is fitted into a stage 31 which is a housing, and a pre-load is applied after assembly into the swivel base 32 and the stage 31, with a plurality of balls arranged between the inner and the outer rings. Between the outer peripheral surface of the swivel base 32 and the inner peripheral surface of the inner ring, a loose engagement is established under such condition as a pre-load is not applied yet to the rolling bearing 10, but a tight engagement is established under such condition as the pre-load is applied to the rolling bearing 10. Here, φd<(φD+φd)/2 is satisfied, where φD is the outer diameter of the outer ring of the bearing, φd is inner diameter of the inner ring, and φdis a diameter of pitch circle of the balls. Further, under such condition as the pre-load is applied to the rolling bearing 10, the contraction amount of the inner diameter of inner ring is set to be larger than the expansion amount of the outer diameter of the outer ring.

Description

The present invention includes, for example, industrial machines, robot joints and turning mechanisms, rotary tables and spindle turning mechanisms for machine tools, rotation mechanisms such as drums for printing machines, direct motor rotation support parts, medical devices, semiconductors / The present invention relates to a bearing device for supporting a rotating shaft such as a liquid crystal manufacturing apparatus, an optical and an optoelectronic apparatus.

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. As shown in FIGS. 4 to 7, a cross roller bearing 100, a four-point contact ball bearing 110, a combined angular ball bearing 120, a combined tapered roller bearing 130, and the like are used for the support portion (for example, Patent Documents). 1).

As shown in FIG. 4, the cross roller bearing 100 has a plurality of cylindrical rollers 103 arranged between an inner ring 101 and an outer ring 102 so as to roll freely. As shown in FIG. 4, a plurality of balls 113 are arranged between the inner ring 111 and the outer ring 112 so as to be freely rollable. These bearings 100 and 110
Can receive radial load, axial load in both directions, and moment load with a single rolling bearing.

Further, as shown in FIG. 6, the combined angular ball bearing 120 is a combination of angular ball bearings 124, 124 in which a plurality of balls 123 are rotatably arranged between an inner ring 121 and an outer ring 122 in two rows. Similarly, as shown in FIG. 7, the combination tapered roller bearing 130 includes tapered roller bearings 134 and 134 in which a plurality of tapered rollers 133 are rotatably disposed between an inner ring 131 and an outer ring 132. These are combined in two rows via a spacer 135 and an outer ring spacer 136. These bearings 120 and 130 also receive a radial load, an axial load in both directions, and a moment load by combining two single row bearings.

As a ball bearing described in Patent Document 1, a narrow bearing having a reduced axial width has been proposed for the purpose of reducing the axial size.

These bearings are used with a predetermined preload. By eliminating backlash inside the bearing, vibration during rotation can be prevented, maintenance of rotation accuracy can be improved, and radial rigidity, axial rigidity, and moment rigidity of the bearing can be reduced. Increases are being made.

As a method for applying a preload to the bearing, for example, in the rear combined angular ball bearing 120A, as shown in FIG. 8, the clearance Δ between the opposed end surfaces of the combined inner rings 121A and 121A is adjusted, and incorporated into the shaft. The inner ring 121A, 121A is moved in the axial direction by a member such as a inner ring presser or the like to eliminate the above-described gap Δ (the opposing end surfaces are brought into close contact with each other to make the gap Δ zero). Thus, a preload (so-called fixed position preload) is applied to the back combination angular contact ball bearing 120A by elastic deformation in the bearing.

Furthermore, these rolling bearings are incorporated in the respective members by using a fit between the shaft and the inner ring or a fit between the housing and the outer ring as a clearance fit or a close fit.

By the way, in the case of the cross roller bearing 100, since the rolling element is a cylindrical roller 103 and the rolling contact surface of the roller 103 is in line contact with the raceway grooves 101a and 102a, the torque is large, and the shaft Due to slight deformation when assembled in a housing, the contact state of the line contact portion becomes uneven, and torque unevenness is likely to occur.

Further, in the four-point contact ball bearing 110, since the rolling element is the ball 113, the torque is smaller than that of the cross roller bearing 100 of the same dimension when receiving a pure axial load or when the axial load is more dominant than the radial load. On the other hand, when the radial load is dominant with respect to the axial load, or when receiving a pure radial load, each ball 113 comes into contact with the raceway grooves 111a and 112a at four points, so the balls 113 and the raceway grooves 111a and 112a Spin slip is large and torque is large.

Furthermore, in these rolling bearings, for example, when the inner ring is attached to the shaft with a clearance fit and the inner ring rotates under a radial load in one direction, harmful slip in the circumferential direction between the inner ring and the shaft (referred to as creep). ) May occur. The slip phenomenon of the raceway called creep is that when the fitting surface is a clearance fit, the load point moves in the circumferential direction as the raceway rotates, and the raceway is positioned in the circumferential direction with respect to the shaft and housing. This is to cause a shift.

Once creep has occurred, the mating surfaces wear significantly and often damage the shaft or housing. Repair and replacement of the shaft and housing is much larger than replacement of the bearing alone, and it takes time to recover the machine. In addition, wear powder may enter the bearing and cause abnormal heat generation, vibration, and the like.

This creep cannot often be prevented by simply tightening the bearing in the axial direction with a bearing nut or the like. Therefore, normally, in the fitting of the bearing, an interference is given to the bearing ring that rotates under load, and it is fixed to the shaft or the housing by an interference fit to prevent creep during operation.

Moreover, the improvement of rotational accuracy is mentioned as the other objective made into an interference fit. In a rotary table or spindle turning mechanism of a machine tool, the fit between the bearing and the shaft or the housing is a clearance fit.For example, when the inner ring rotates and the shaft and the inner ring are a clearance fit, the center of the shaft and the center of the inner ring are shifted and the shaft is offset. By rotating the core, the lathe machining causes a roundness of the processed surface to be broken or a defect in the stitching, and the milling process deteriorates the quality of the processed surface, such as a shape loss or a deterioration in roughness. In the rotary drum of a printing press, if the rotational accuracy is deteriorated for the above reasons, the printing accuracy is affected. In the case of color multiplex printing, problems such as uneven color and bleeding of characters occur.

For the above reasons, the race ring is often assembled by tight fitting, but in the case of tight fitting, it is naturally necessary to press-fit with a press or the like, or shrink fit or the like when assembling. In the above applications, a relatively large bearing having a bearing inner diameter of φ100 to φ300 mm is often used, and in the case of tight fitting, the assembling work is not easy. In addition, when disassembling the bearing from the shaft or housing, it is necessary to design the structure of the peripheral portion so that a load in the opposite direction to that when assembled into the tightly fitted race is applied. There are many configurations in which the rotor and the stator are arranged beside the bearing in the rotation support portion bearing of the direct drive motor, and it is difficult to design the structure in consideration of the disassembly method.

In particular, in the case of the angular ball bearing 124, as shown in FIG. 9, it has a structure that can only apply a load in one direction as a single unit. When a load in the opposite direction is applied, the groove shoulder edge portion of the inner and outer rings 121, 122 and the ball 123 Contact with each other to cause ball damage, or the ball bearing 124 is separated and cannot be reused. Therefore, sufficient consideration is required when assembling and disassembling.

As a countermeasure against the above, for example, Patent Document 2 discloses that a rolling bearing after incorporation is a clearance fit between the outer circumferential surface of the shaft and the inner circumferential surface of the inner ring before the preload is applied to the rolling bearing after incorporation. In a state where a preload is applied to the inner ring, a bearing device is disclosed that is tightly fitted by contraction in the radial direction of the inner peripheral surface of the inner ring.

According to the bearing device having the above configuration, when the inner ring is incorporated into the shaft, it is not necessary to use a press or shrink fit, so that the inner ring can be easily incorporated. Also, when the inner ring is disassembled from the shaft, a load is applied to the bearing. It can be done smoothly. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. Further, since the inner ring and the shaft are closely fitted after the preload is applied, the occurrence of creep and the deterioration of the rotation accuracy can be prevented.

Furthermore, in Patent Document 2, in a state before preload is applied to the rolling bearing after assembly, the inner peripheral surface of the housing and the outer peripheral surface of the outer ring are clearance-fitted, and preload is applied to the assembled rolling bearing. Also disclosed is a bearing device that is tightly fitted by expansion in the radial direction of the outer peripheral surface of the outer ring.

According to the bearing device having the above-described configuration, when the outer ring is incorporated into the housing, it is not necessary to use a press or shrink fit, so that it can be easily incorporated. It can be done smoothly. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. In addition, since the outer ring and the housing are closely fitted after the preload is applied, the occurrence of creep and the deterioration of the rotation accuracy can be prevented.

On the other hand, the bearing device is mostly used for inner ring rotation, and further measures are required for the occurrence of fretting and creep that are likely to occur under inner ring rotation conditions.

JP 2006-105385 A JP 2009-002504 A

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a bearing device that can more reliably prevent creep generated by inner ring rotation.

The above object of the present invention is achieved by the following configurations.
(1) A rolling bearing having a shaft, a housing, and an inner ring fitted on the shaft, an outer ring fitted on the housing, and a plurality of balls disposed between the inner ring and the outer ring. A bearing device comprising:
A state in which the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring are clearance-fitted before the preload is applied to the rolling bearing after the assembly, and the preload is applied to the rolling bearing after the assembly In the inner ring, it is an interference fit by shrinkage in the radial direction of the inner peripheral surface,
Furthermore, the outer ring outer diameter of the bearing [phi] D, the inner ring inner diameter .phi.d, the pitch circle diameter of the ball when the .phi.d _m, satisfies the _{φd m <(φD + φd)} / 2 conditions, and the rolling bearing after the incorporation A bearing device, wherein an inner ring inner diameter contraction amount is set larger than an outer ring outer diameter expansion amount in a state where a preload is applied.
(2) A rolling bearing having a shaft, a housing, and an inner ring that is fitted on the shaft, and an outer ring that is fitted on the housing, and having a plurality of balls disposed between the inner ring and the outer ring. A bearing device comprising:
A state in which the inner peripheral surface of the housing and the outer peripheral surface of the outer ring are clearance fitted in a state before preload is applied to the rolling bearing after the assembly, and the preload is applied to the rolling bearing after the assembly In the above, an interference fit is obtained by expansion of the outer peripheral surface of the outer ring in the radial direction,
Furthermore, the outer ring outer diameter of the bearing [phi] D, the inner ring inner diameter .phi.d, the pitch circle diameter of the ball when the .phi.d _m, satisfies the _{φd m <(φD + φd)} / 2 conditions, and the rolling bearing after the incorporation A bearing device, wherein an inner ring inner diameter contraction amount is set larger than an outer ring outer diameter expansion amount in a state where a preload is applied.
(3) The rolling bearing has an axial sectional width B
(1) or (2), wherein the ball bearing has a cross-sectional dimension ratio (B / H) of 0.1 <B / H <0.63. Bearing device.

According to the bearing device of the present invention, the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring are clearance-fitted in a state before preload is applied to the rolling bearing after assembly, and the preload is applied to the rolling bearing after assembly. When the inner ring is attached, the inner ring is contracted in the radial direction so that the inner ring can be easily fitted because there is no need to use a press or shrink fit when the inner ring is incorporated into the shaft. Also, when the inner ring is disassembled from the shaft, it can be carried out smoothly without applying a load to the bearing. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. Further, since the inner ring and the shaft are closely fitted after the preload is applied, the occurrence of creep and the deterioration of the rotation accuracy can be prevented.

Furthermore, when the outer ring outer diameter of the bearing is φD, the inner ring inner diameter is φd, and the pitch circle diameter of the balls is φdm, the condition of φdm <(φD + φd) / 2 is satisfied, and the preloaded rolling bearing is assembled. Since the inner ring inner diameter contraction amount is set to be larger than the outer ring outer diameter expansion amount, the rigidity of the bearing used for inner ring rotation can be further improved and the rotation accuracy can be further improved, and creep can be reliably prevented. can do.

It is the side view which made the principal part the cross section which shows the main spindle turning apparatus of the machine tool which is a bearing apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the 2 rows back combination angular contact ball bearing of this embodiment. It is sectional drawing which shows the conventional 2 rows back combination angular contact ball bearing. It is sectional drawing of a cross roller bearing. It is sectional drawing of a 4-point contact ball bearing. It is sectional drawing of a two-row combination angular contact ball bearing. It is sectional drawing of a two-row combination tapered roller bearing. It is sectional drawing which shows the state before preload provision of a 2 row combination angular contact ball bearing. It is sectional drawing which shows the addition direction of the load of an angular contact ball bearing. (A) is sectional drawing which shows the 2 row back combination angular ball bearing integrated by clearance fitting, (b) is sectional drawing which shows the 2 row back combination angular ball bearing integrated by interference fitting.

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

FIG. 1 shows a spindle turning device for a machine tool, which is a bearing device of the present invention, used for a 5-axis machining machining center, for example. In the figure, reference numeral 30 denotes a spindle turning device 30 of a machine tool, which is supported by a base 31 (hereinafter also referred to as “housing”) fixed to a fixed portion of a machining center and rotatably supported by the base 31. And a main spindle 33 mounted on the swivel base 32, and adopts a drive system using a direct motor 63.

The base 31 has a housing recess 34 that houses a swivel base 32 that is recessed from the center of the left end surface to the right side. The swivel base 32 is a main shaft swivel bearing (hereinafter referred to as a “rolling bearing”). It is also referred to as "."

The swivel base 32 includes a base portion 64 that holds the main spindle turning portion ball bearing 10 and the rotor 62, and a disc portion 65 that also serves as an inner ring presser of the main spindle turning portion ball bearing 10 that is bolted to the base portion 64. ing. The base 64 has a protruding portion 42 formed with a recess 41 for reducing the weight from the right end of the central portion to the left, and the disc portion 65 is opposed to the left end surface of the base 64 and is mounted flat on the left end. It has a surface 36.

The main spindle body 33 is provided with a main spindle 52 equipped with a rotational drive source for rotating a tool with a tool mounting surface 51 for attaching a tool (not shown) such as an end mill or a drill, and a disk portion 65 of the swivel base 32 attached. It has a mounting plate portion 53 that is bolted to the surface 36 and formed integrally with the side surface of the main shaft 52.

The main spindle turning device 30 includes a stator 61 disposed on the inner peripheral surface of the housing recess 34 of the base 31 and a rotor 62 disposed on the outer peripheral surface of the protruding portion 42 of the swivel base 32 facing the stator 61. The direct motor 63 is provided, and the direct motor 63 directly drives the turning base 32 to turn. The direct motor 63 is not limited to the outer rotor type shown in FIG. 1, and is an inner rotor type in which a rotor is provided on the inner peripheral surface of the concave portion 41 of the projecting portion 42 and a stator is provided inside the rotor. You may make it comprise.

The main shaft turning part ball bearing 10 is a combination angular contact ball bearing in which two rows of narrow angular ball bearings 14 are combined in the back side. As shown in FIGS. 1 and 2, each angular ball bearing 14 includes an inner ring 11 that is externally fitted to the swivel base 32, an outer ring 12 that is internally fitted to the base 31, and each raceway surface of the inner ring 11 and the outer ring 12. A ball 13 that is a plurality of rolling elements that are arranged to freely roll with a contact angle between 11a and 12a. Each angular ball bearing 14 may be provided with a cage or a seal.

Each inner ring 11 is fixed to the stepped portion 38 by tightening the disc portion 65 that also serves as an inner ring presser with a bolt 44 in a state of being fitted on the stepped portion 38 formed on the swivel base 32. On the other hand, each outer ring 12 is bolted to the outer ring presser 46 disposed on the left end surface side of the base 31 with a bolt 47 in a state in which the outer ring 12 is fitted in a step 45 formed in the housing recess 34 of the base 31. Thus, the base 31 is fixed. Further, by fastening the disc portion 65 with bolts, the axial clearance between the opposed end faces of the inner rings 11 is set to 0, and a fixed position preload is applied to the ball bearing 10 by elastic deformation in the bearing. At this time, it is preferable to ensure the axial clearance Δ1 (see FIG. 1) between the swivel base 32 and the disc portion 65 in a state where the axial clearance between the opposed end surfaces of the inner ring 11 becomes zero. In order to suppress variation in the pressing force on the inner ring 11 and to add an appropriate preload, Δ1 is usually about 0.01 to 0.05 mm.

Each narrow angular ball bearing 14 has a cross section of an axial cross section width B and a radial cross section height H (= (outer ring outer diameter D−inner ring inner diameter d) / 2) in order to save space in the axial direction. The dimension ratio (B / H) is set to (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 addition, the narrow angular contact ball bearing is designed to use a plurality of balls having a smaller diameter than a standard design bearing, and the inner and outer rings have a thick radial cross-sectional thickness. Therefore, the cross-sectional secondary moment is high and the radial rigidity is high. Therefore, the characteristic which is hard to deform | transform with respect to the heavy load from the periphery is hold | maintained. From the above, the inner and outer rings 11 when the bearing 10 is fixed by the disk portion 65, the outer ring retainer 46, etc., when incorporated in the shaft 32 or the housing 31 (particularly when assembled by clearance fitting with the shaft 32 or the housing 31). , 12 (especially deterioration of roundness) can be suppressed, and defects such as torque failure and rotation accuracy caused by deformation, increased heat generation, wear and seizure can be prevented.

Furthermore, when the width dimension is about half that of the conventional standard single-row ball bearing, the ball diameter is also about half that of the conventional ball bearing. Increased against ball bearings.

Here, in this embodiment, as described above, by fixing the disc portion 65 with bolts, a fixed position preload is applied to the ball bearing 10 by elastic deformation in the bearing, but a preload is applied to the rolling bearing 10. In the state before being performed, each fit between the outer peripheral surface of the swivel base 32 and the inner peripheral surface of the inner ring 11 and between the inner peripheral surface of the base 31 and the outer peripheral surface of the outer ring 12 is a clearance fit. It is said that. Then, in a state in which a preload is applied to the rolling bearing 10, each fit is a tight fit due to contraction of the inner peripheral surface of the inner ring 11 in the radial direction and expansion of the outer peripheral surface of the outer ring 12 in the radial direction.

Specifically, a method for assembling the rolling bearing 10 to the turning pedestal 32 and the base 31 will be described. First, two rows of angular ball bearings 14 are inserted into the stepped portion 38 of the turning pedestal 32 in a combined state of the back surface. In this state, the fit between the outer peripheral surface of the swivel base 32 and the inner peripheral surface of the inner ring 11 is a clearance fit. The outer ring presser 46 is fitted to the outer ring 12 of one of the angular ball bearings 14 (left side in FIG. 1).

Next, after assembling the disc portion 65 that also serves as an inner ring presser to the turning pedestal 32 that is the shaft, the disc portion 65 is lightly temporarily fastened to the turning pedestal 32 with bolts 44 so that no preload is applied to the bearing. By lightly tightening temporarily, the two angular ball bearings 14 become a combination bearing, and a load in the reverse direction as shown in FIG. Moreover, the combination angular contact ball bearing 10 is inserted into the end hole of the receiving recess 34 of the base 31 which is a housing. Since no preload is applied to the bearing, the fit between the inner peripheral surface of the base 31 and the outer peripheral surface of the outer ring 12 is also a clearance fit.

Then, when the bolt 44 of the disc portion 65 is tightened with an appropriate torque and the inner ring 11 is fixed, the set preload is applied to the combined angular ball bearing 10 for the first time. Thereafter, the bolt 47 of the outer ring presser 46 is tightened with an appropriate torque.

With the preload applied, the inner peripheral surface of the inner ring 11 contracts in the radial direction, and the outer peripheral surface of the outer ring 12 expands in the radial direction, so that the outer peripheral surface of the swivel base 32 and the inner peripheral surface of the inner ring 11 Each fit between the inner peripheral surface of the base 31 and the outer peripheral surface of the outer ring 12 is a tight fit. As a result, there is no gap before assembly, and problems such as creep and rotational vibration can be prevented.

In addition, in the state before the preload is applied, the fitting clearances between the turning pedestal 32 and the inner ring 11 and the base 31 and the outer ring 12 are the set preload load, the preload load, and the radial expansion and contraction of the inner ring and the outer ring. It is set in consideration of the relationship with the amount, the fitting clearance after applying preload, and the like. Further, since the radial clearance amount in the bearing also changes due to the expansion and contraction of the inner ring 11 and the outer ring 12 in the radial direction, the preload clearance is set in consideration of the change amount of the radial clearance in addition to the set preload load. .

Further, when it is desired to further prevent a decrease in rigidity (a decrease in preload) due to the radial expansion and contraction of the bearing ring, for example, a fitting clearance between the shaft 32 or the housing 31 and the bearing 10 is respectively set as required. About half or less of the amount of expansion and contraction in the radial direction (in this embodiment, the clearance between the shaft 32 and the inner ring 11: 0.001 to 0.010 mm, or the clearance between the housing 31 and the outer ring 12: 0.001 It may be set to about 0.015 mm). If set in this way, the amount of expansion and contraction of the bearing is suppressed, and after applying the preload, a moderate interference fit is obtained, so that rigidity can be ensured. Further, creep and vibration during rotation can be further prevented.

Furthermore, in the present embodiment, [phi] D the outer ring outer diameter of the bearing 14, the inner ring inner diameter .phi.d, the pitch circle diameter of the ball when the Faidm, meet _{φd m <(φD + φd)} / 2 conditions, and the incorporation By setting the inner ring inner diameter contraction amount larger than the outer ring outer diameter expansion amount in the state where the pre-load is applied to the subsequent rolling bearing, the inner ring interference in the state where the pre-load is applied can be further increased. Fretting and creep that are likely to occur under rotating conditions can be further prevented. In addition, it is easy to obtain the fitting fitting condition between the inner ring and the shaft for setting the inner ring interference after the preload load is applied (the fitting range can be set wide).

In general industrial machinery, the inner ring is rotated and the outer ring is not rotated (stationary). In this case, in order to improve the rotation accuracy of the inner ring on the rotating shaft side, or to suppress fretting and creep due to vibration load during rotation, it is necessary to make an interference fit. In addition, when the interference reduction due to the external load is taken into account, it is necessary to secure an appropriate interference corresponding to the external load value. On the other hand, when rigidity or the like is not so much required on the outer ring side that is a fixed ring, there is no problem in operation as much as fretting and creep are hard to occur even with intermediate fit or slight clearance fitting.

In the case of conventional bearings, the ball pitch circle diameter is set at the center in the radial direction of the inner and outer rings. In this case, the amount of radial deformation of the inner and outer rings due to preload (the outer ring expands and the inner ring contracts) The outer ring side becomes larger due to the difference in stress direction acting on the outer ring. As a result, with conventional bearings (ball pitch circle diameter in the center position in the radial direction), when the fitting range is the same for the inner and outer rings, the interference due to the outer ring expansion and inner ring contraction after preload is required to fit. The inner ring side is smaller, but by adopting this embodiment, the inner ring side can have a larger maximum interference and a wider fit range for interference. On the other hand, the outer ring side has a narrow fit range for interference, but there is no problem because it may be an intermediate fit or the worst clearance as described above.

One of the effects of preventing the deterioration of rotational accuracy is due to the following reason.
That is, when the space between the outer peripheral surface of the shaft (swivel pedestal) 32 and the inner peripheral surface of the inner ring 11 and the inner peripheral surface of the housing (base) 31 and the outer peripheral surface of the outer ring 12 are assembled with a clearance fit. As shown in FIG. 10 (a), there is a high possibility that the axis is displaced in the radial direction between the two rows of inner rings 11, 11 and between the outer rings 12, 12. When the rolling bearing rotates in a state where such misalignment has occurred, a whirling motion such as a hulling motion occurs, and the rotational accuracy deteriorates. On the other hand, in the present invention, since it is incorporated with a tight fit after preloading, there is no misalignment between the inner rings 11 and 11 and between the outer rings 12 and 12, as shown in FIG. it can.

In particular, in this embodiment, the narrow angular ball bearing 14 having a cross-sectional dimension ratio of 0.1 <B / H <0.63 is used, so that the axial cross-sectional thickness of the inner and outer rings 11 and 12 is small. It is thin, and the expansion and contraction deformation of the inner and outer rings 11 and 12 due to preload is also increased, so the effect is great. That is, in the case of a rolling bearing having a standard size, the inner and outer rings 11 and 12 have a large cross-sectional thickness, and the required preload for application is small. Since the amount of shrinkage was slight, the effect of the fitting clearance was small. However, in the narrow angular contact ball bearing 14, the expansion and contraction deformation of the inner and outer rings 11 and 12 due to the preload is larger than that, and the present invention is required.

In addition, since the rotary table of the machine tool, the spindle turning mechanism part, the drum rotating part of the printing machine, etc. require high rigidity and space saving, the narrow angular ball bearing 14 has these structures. It is effective for. In addition, because the rigidity is increased, the preload to be set is as large as several hundred kg or more, so that the expansion and contraction deformation is increased, and the above effect can be exhibited more.

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.

As the rolling bearing of the present invention, a tapered roller bearing, a deep groove ball bearing, a cross roller bearing, a four-point contact ball bearing and the like can be applied in addition to the angular ball bearing of the present embodiment. Moreover, in the case of a combination bearing, it is good also as 2 rows or more, for example, a 3 row combination, and a 4 row combination angular contact ball bearing as needed.

Furthermore, in order to improve moment rigidity, an inner ring spacer or an outer ring spacer may be inserted between the combined bearings. Further, the combination method may be a front combination in which the direction of the contact angle is a cross-shaped shape as shown in FIG.

As a method for applying the preload, in addition to a fixed position preload method using a combination of two or more rows of bearings, a constant pressure preload method capable of applying an appropriate preload using a spring may be adopted. The preload application method and structure can be selected in a timely manner within the scope of the present invention.

In the spindle turning device of the present embodiment, the case where the turning base 32 is rotatably supported in the housing recess 34 formed in the base 31 has been described, but the present invention is not limited to this, and the base 31 is not limited thereto. Alternatively, the swivel base 32 may be rotatably supported via the main shaft swivel ball bearing 10.

Furthermore, in the present embodiment, each fit between the outer peripheral surface of the shaft 32 and the inner peripheral surface of the inner ring 11 and between the inner peripheral surface of the housing 31 and the outer peripheral surface of the outer ring 12 is in the rolling bearing 10. In the state before the preload is applied, the clearance fit is used, and in the state where the preload is applied to the rolling bearing 10, the fit is applied. However, in the present invention, at least one of these fits is applied to the rolling bearing 10. In this state, it is only necessary to make an interference fit, and one fit may remain in a clearance fit state after the preload is applied.

In the present invention, at least one of these fits may be a clearance fit in a state before the preload is applied to the rolling bearing 10, and one fit may be a tight fit before the preload is applied. . In that case, the other fit, which is a clearance fit, is a tight fit after the preload is applied.

The present invention includes, for example, industrial machines, robot joints and turning mechanisms, rotary tables and spindle turning mechanisms for machine tools, rotation mechanisms such as drums for printing machines, direct motor rotation support parts, medical devices, semiconductors / It can be suitably used for a bearing device for supporting a rotating shaft such as a liquid crystal manufacturing apparatus, an optical and an optoelectronic device, and an assembling method thereof.

10 Bearing for spindle turning part (rolling bearing)
11 Inner ring 12 Outer ring 13 Ball (rolling element)
14 Angular contact ball bearing 30 Spindle turning device (bearing device)
31 base (housing)
32 swivel base (axis)

Claims (3)

A shaft, a housing, and an inner ring fitted to the shaft; and an outer ring fitted to the housing, and a rolling bearing having a plurality of balls disposed between the inner ring and the outer ring. A bearing device,
A state in which the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring are clearance-fitted before the preload is applied to the rolling bearing after the assembly, and the preload is applied to the rolling bearing after the assembly In the inner ring, it is an interference fit by shrinkage in the radial direction of the inner peripheral surface,
Furthermore, the outer ring outer diameter of the bearing [phi] D, the inner ring inner diameter .phi.d, the pitch circle diameter of the ball when the .phi.d _m, satisfies the _{φd m <(φD + φd)} / 2 conditions, and the rolling bearing after the incorporation A bearing device, wherein an inner ring inner diameter contraction amount is set larger than an outer ring outer diameter expansion amount in a state where a preload is applied. A shaft, a housing, and an inner ring fitted to the shaft; and an outer ring fitted to the housing, and a rolling bearing having a plurality of balls disposed between the inner ring and the outer ring. A bearing device,
A state in which the inner peripheral surface of the housing and the outer peripheral surface of the outer ring are clearance fitted in a state before preload is applied to the rolling bearing after the assembly, and the preload is applied to the rolling bearing after the assembly In the above, an interference fit is obtained by expansion of the outer peripheral surface of the outer ring in the radial direction,
Furthermore, the outer ring outer diameter of the bearing [phi] D, the inner ring inner diameter .phi.d, the pitch circle diameter of the ball when the .phi.d _m, satisfies the _{φd m <(φD + φd)} / 2 conditions, and the rolling bearing after the incorporation A bearing device, wherein an inner ring inner diameter contraction amount is set larger than an outer ring outer diameter expansion amount in a state where a preload is applied. The rolling bearing is a ball bearing in which a sectional dimension ratio (B / H) between an axial sectional width B and a radial sectional height H is 0.1 <B / H <0.63. The bearing device according to claim 1 or 2.

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