JP2010106867A - Bearing device and method for assembling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device improved in assembling/disassembling performance of a bearing, maintaining the rigidity of the bearing, improved in rotation accuracy, and preventing creep, and to provide a method for manufacturing the bearing device. <P>SOLUTION: This method for manufacturing the bearing device includes: a process for assembling the bearing 10 in a swivel base 32 and a base 31 in the state of fitting in at least one of spaces between the outer peripheral surface of the swivel base 32 as a shaft and the inner peripheral surface of an inner ring and between the inner peripheral surface of the base 31 as a housing and the outer peripheral surface of an outer ring; a process for applying a predetermined pre-load to the bearing 10 after the assembling process. In the pre-load applying process, when a predetermined pre-load is applied to the bearing 10, there occurs at least one of shrinkage of the inner peripheral surface of the inner ring in the radial direction for shrink-fitting between the outer peripheral surface of the swivel base 32 and the inner peripheral surface of the inner ring and swelling of the outer peripheral surface of the outer ring in the radial direction for shrink fit between the inner peripheral surface of the base 31 and the outer peripheral surface of the outer ring. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes, for example, industrial machines, robot joints, turning mechanisms and reduction mechanisms, rotary tables and spindle turning mechanisms for machine tools, rotating mechanisms such as drums for printing machines, direct motor rotation supports, medical The present invention relates to a bearing device for supporting a rotating shaft such as a device, a semiconductor / liquid crystal manufacturing device, an optical device, and an optoelectronic device, and an assembling method thereof.

  Usually, for example, a rotation mechanism part such as a rotary table of a machine tool, a spindle turning part of a machine tool, a drum rotary shaft of a printing machine, a robot joint, a turning mechanism part, a speed reduction mechanism part, and these parts are rotated. As shown in FIGS. 17 to 20, a cross roller bearing 100, a four-point contact ball bearing 110, a combined angular ball bearing 120, a combined tapered roller bearing 130, etc. are used for the rotation support portion of the direct motor ( For example, see Patent Document 1).

  As shown in FIG. 17, in the cross roller bearing 100, a plurality of cylindrical rollers 103 are rotatably arranged between an inner ring 101 and an outer ring 102, and the four-point contact ball bearing 110 is shown in FIG. As shown, 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 are a single rolling bearing and can receive a radial load, an axial load in both directions, and a moment load.

  Further, as shown in FIG. 19, 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. 20, 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.

  For example, in the rear combined angular contact ball bearing 120A, as shown in FIG. 21, the clearance -Δ between the opposed end faces of the combined inner rings 121A, 121A is adjusted and assembled into the shaft. 121A and 121A are moved in the axial direction to eliminate the above-mentioned clearance −Δ (the opposing end surfaces are brought into close contact with each other to make −Δ 0). 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.

JP 2006-105385 A

  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. 22, it has a structure that can only apply a load in one direction as a single unit, and when a load in the opposite direction is applied, the groove shoulder edge portion of the inner and outer rings 121 and 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.

  The present invention has been made in view of the above-described circumstances, and its purpose is to improve creepability as well as to improve the ease of assembly and disassembly of the bearing, to maintain the rigidity of the bearing and to improve rotational accuracy. It is to provide an apparatus and an assembly method thereof.

The above object of the present invention is achieved by the following configurations.
(1) A bearing device comprising: a shaft, a housing, and an inner ring fitted onto the shaft, and an outer ring fitted inside the housing, and a rolling bearing to which preload is applied after being incorporated into the shaft and the housing. Because
The rolling bearing has a plurality of balls arranged between the inner ring and the outer ring,
The inner ring effective wall thickness ratio Yi = ti when the maximum inner wall thickness ti1, the minimum wall thickness ti2, the inner ring inner diameter d, the effective wall thickness ti = ti1- (ti1-ti2) / 4, and the effective outer diameter Dit = d + 2ti. / Dit,
The outer ring effective thickness ratio when the maximum thickness to1, the minimum thickness to2, the outer ring outer diameter Dt, the effective thickness to = to1- (to1-to2) / 3, and the effective outer diameter Dot = Dt of the outer ring. Yo = to / Dot,
3% ≦ Yi, Yo ≦ 5% ball bearing,
A state in which 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 ball bearing after the assembly, and the preload is applied to the ball bearing after the assembly The bearing device according to claim 1, wherein the inner ring has an interference fit by contraction in a radial direction.
(2) A bearing device comprising: a shaft, a housing, and an inner ring fitted onto the shaft, and an outer ring fitted inside the housing, and a rolling bearing to which preload is applied after being incorporated into the shaft and the housing. Because
The rolling bearing has a plurality of balls arranged between the inner ring and the outer ring,
The inner ring effective wall thickness ratio Yi = ti when the maximum inner wall thickness ti1, the minimum wall thickness ti2, the inner ring inner diameter d, the effective wall thickness ti = ti1- (ti1-ti2) / 4, and the effective outer diameter Dit = d + 2ti. / Dit,
The outer ring effective thickness ratio when the maximum thickness to1, the minimum thickness to2, the outer ring outer diameter Dt, the effective thickness to = to1- (to1-to2) / 3, and the effective outer diameter Dot = Dt. Yo = to / Dot,
3% ≦ Yi, Yo ≦ 5% ball bearing,
The inner peripheral surface of the housing and the outer peripheral surface of the outer ring are in a state in which a preload is applied to the ball bearing after the incorporation, and a preload is applied to the ball bearing after the assembly. The bearing device is characterized in that the outer ring has an interference fit by expansion in the radial direction.
(3) The ball bearing is characterized in that a cross-sectional dimension ratio (B / H) between an axial cross-sectional width B and a radial cross-sectional height H is 0.1 <B / H <0.63. The bearing device according to (1) or (2).

(4) A bearing device including a shaft, a housing, and an inner ring fitted onto the shaft, and an outer ring fitted inside the housing, and a rolling bearing to which preload is applied after being assembled into the shaft and the housing. The assembly method of
In a state where at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring and at least one of the inner peripheral surface of the housing and the outer peripheral surface of the outer ring is fitted with clearance, the shaft and the housing are Incorporating a rolling bearing;
A step of applying a predetermined preload to the rolling bearing after the assembling step,
The rolling bearing has a plurality of balls arranged between the inner ring and the outer ring,
The inner ring effective wall thickness ratio Yi = ti when the maximum inner wall thickness ti1, the minimum wall thickness ti2, the inner ring inner diameter d, the effective wall thickness ti = ti1- (ti1-ti2) / 4, and the effective outer diameter Dit = d + 2ti. / Dit,
The outer ring effective thickness ratio when the maximum thickness to1, the minimum thickness to2, the outer ring outer diameter Dt, the effective thickness to = to1- (to1-to2) / 3, and the effective outer diameter Dot = Dt of the outer ring. Yo = to / Dot,
3% ≦ Yi, Yo ≦ 5% ball bearing,
In the preload application step, when the predetermined preload is applied to the ball bearing, a radial fit of the inner peripheral surface of the inner ring that fits between the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring is performed. A method for assembling a bearing device, characterized in that at least one of contraction and expansion in the radial direction of the outer peripheral surface of the outer ring, which is tightly fitted between the inner peripheral surface of the housing and the outer peripheral surface of the outer ring, is generated. .
(5) The ball bearing is characterized in that a cross-sectional dimension ratio (B / H) between an axial cross-sectional width B and a radial cross-sectional height H is 0.1 <B / H <0.63. A method for assembling the bearing device according to (4).

  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.

  According to another bearing device of the present invention, the inner peripheral surface of the housing and the outer peripheral surface of the outer ring are clearance-fitted in a state before the preload is applied to the rolling bearing after being assembled, and the rolling bearing after being assembled. In the state where preload is applied to the outer ring, the outer ring is radially fitted on the outer peripheral surface, so that it is not necessary to use a press or shrink fit when installing the outer ring into the housing. In addition, when disassembling the outer ring from the housing, it can be performed 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. 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.

  Further, according to the assembly method of the bearing device of the present invention, a clearance fit is provided between at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring and between the inner peripheral surface of the housing and the outer peripheral surface of the outer ring. A rolling bearing is incorporated into the shaft and the housing, and a step of applying a predetermined preload to the rolling bearing after the assembling step. The preloading step includes a step of applying the predetermined preload to the rolling bearing. Of the inner ring of the inner ring with a close fit between the outer peripheral face of the inner ring and the inner peripheral face of the inner ring, and the outer ring with a tight fit between the inner peripheral face of the housing and the outer peripheral face of the outer ring. Since at least one of the expansion of the outer peripheral surface in the radial direction occurs, it is not necessary to use a press or shrink fit when installing the bearing in the shaft or housing, so it can be easily installed, and when disassembling the bearing, Without applying load to the bearing It can be carried out in the Meuse. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. In addition, since the gap between the bearing and the shaft / housing becomes an interference after the preload is applied, the occurrence of creep and the deterioration of the rotation accuracy can be prevented.

  That is, when the gap between the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring and between the inner peripheral surface of the housing and the outer peripheral surface of the outer ring is assembled with a clearance fit, the shaft core is between the two inner rings and between the outer rings. Is likely to shift in the radial direction. 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 and between the outer rings, and the rotation accuracy can be improved.

Hereinafter, a bearing device and an assembly method thereof 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 shaft 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 shaft 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 disk 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, both axial load and moment load can be applied. Is 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.

Here, FIG. 5 and FIG. 6 are each a standard thin ball bearing (bearing inner diameter: φ38.1 mm, bearing outer diameter: φ47.625 mm, bearing width: 4.762 mm, cross-sectional dimension ratio (B / H) = 1) as a reference, the radius of the inner and outer ring rings when the bearing inner diameter is changed without changing the bearing outer diameter and bearing width (that is, when the value of (B / H) is changed) direction of deformation characteristics (see Figure 3: the inner ring of illustration) and radial cross-sectional secondary moment I: shows the result of comparison (see FIG. 4 calculated as I = bh ^3/12).

  7 and 8 are also used as standard thin ball bearings (bearing inner diameter: φ63.5 mm, bearing outer diameter: φ76.2 mm, bearing width: 6.35 mm, cross-sectional dimension ratio (B / H) = 1) as a reference, the radius of the inner and outer ring rings when the bearing inner diameter is changed without changing the bearing outer diameter and bearing width (that is, when the value of (B / H) is changed) The result of having compared the deformation characteristic of a direction and the cross-sectional secondary moment I of the radial direction is shown.

  In any of the bearings, (B / H) = 0.63, and the change in the rigidity increase rate gradient is noticeable. That is, the increase in the secondary moment I of the cross section becomes significant, and the decrease in the deformation amount of the inner and outer ring in the radial direction becomes saturated. This can prevent bearing deformation due to lathe processing and grinding processing forces when manufacturing inner and outer rings, which is a problem with conventional ultra-thin bearings, and improve bearing accuracy such as roundness and uneven thickness. Can do.

  Further, when the bearing 10 is fixed to the shaft 32 or the housing 31 (particularly when it is assembled by clearance fitting with the shaft 32 or the housing 31), the inner and outer rings 11, 12 deformation (especially deterioration of roundness) can be suppressed, and torque defects and rotational accuracy defects caused by deformation, or problems such as 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.

  The dimension series determined by the International Organization for Standardization (ISO) is 18 (for example, 6824), 19 (for example, 6936), 10 (for example, 7020A), 02 (for example, 7240C), 03 (for example, 7360A). In the standard ball bearing, when the inner diameter of the bearing is φ5 mm to φ500 mm, the cross-sectional dimension ratio (B / H) is B / H = 0.63 to 1.17. Is narrow in the axial direction and does not correspond to the above-mentioned cross-sectional dimension ratio.

  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. 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 of the inner ring and the outer ring. It is set in consideration of the relationship with the amount of contraction, the fitting clearance (interference) after applying the preload. 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. .

  Hereinafter, the setting of the fitting clearance and the preload clearance in this embodiment when the bearing 10 of the product A (narrow product) shown in Table 1 is used will be described. Table 1 shows a comparison of the detailed dimensions of the bearings of the present invention product A and the conventional product.

  FIG. 9 shows the relationship between the preload applied in the fixed position preload of the bearing of the product A of the present invention, the diameter expansion amount in the radial direction of the outer ring and the diameter shrinkage amount of the inner ring in the radial direction, and FIG. The comparison of the radial expansion amount of the outer ring with the conventional product is shown. FIG. 10 shows that the product A of the present invention has a larger amount of expansion and contraction in the radial direction of the races than the conventional product.

In this embodiment, since the set preload is set to 15000 N, the fit between the shaft 32 and the housing 31 and the bearing 10 is set as follows with reference to FIG.
Initial fit between shaft 32 and inner ring 11: clearance less than 0.024 mm Initial fit between housing 31 and outer ring 12: clearance less than 0.026 mm

  Under this condition, even if each clearance is almost the maximum value (shaft and inner ring: ≈ 0.024 mm, housing and outer ring: ≈ 0.026 mm), the fitting clearance after the built-in preload is approximately 0 mm (somewhat It is possible to prevent defects such as creep and the like.

  Further, when it is desired to further prevent a decrease in rigidity (a decrease in preload) due to the expansion and contraction of the raceway in the radial direction, for example, if necessary, a fitting clearance between the shaft 32 or the housing 31 and the bearing 10 may be provided. (In this embodiment, the clearance between the shaft 32 and the inner ring 11 is 0.001 to 0.010 mm, or the clearance between the housing 31 and the outer ring 12 is 0.00. It may be set to about 001 to 0.015 mm). If set in this way, the amount of expansion and contraction of the bearing is suppressed, and after the preload is applied, an appropriate interference fit is obtained, so that rigidity can be ensured. Further, creep and vibration during rotation can be further prevented.

  FIG. 11 shows a case in which the initial setting assumed preload is 15000 N and the fitting between the inner ring 11 and the shaft 32 and the fitting between the outer ring 12 and the housing 31 are respectively set to a clearance of 0.005 mm. A) shows a comparison result of the moment stiffness between the inner and outer rings 11, 12 and the shaft 32 / housing 31 after the preload is applied (fitting condition B). In the fitting condition A, the expansion / contraction amount of the inner and outer rings 11 and 12 is restricted to 0.005 mm, so that moment rigidity can be ensured.

  Further, the preload clearance may be set to be large in advance by an amount corresponding to the preload that decreases due to the expansion and contraction of the inner and outer rings 11 and 12. That is, when the outer diameter of the outer ring expands, the outer ring raceway groove also expands in the radial direction by substantially the same value. Similarly, when the inner ring inner diameter contracts, the inner ring raceway groove also contracts in the radial direction by substantially the same value. As a result, the radial clearance inside the bearing is increased by the amount of expansion and contraction of the raceway groove, and the preload clearance necessary for applying the preload is also reduced. That is, the preload is reduced with respect to the theoretical value where there is no expansion / contraction. For this reason, for example, when the total increase amount of the radial clearance in the bearing due to the expansion and contraction in the radial direction of the inner and outer rings 11 and 12 by the assumed preload of the initial setting is Δr1, the preload clearance is set to Δa1 by the following equation (1). Keep a lot.

The relational expression of the amount of change between the radial clearance of the two-row combination angular ball bearing 10 and the axial preload clearance is expressed by the following equation.
Δa1≈Δr1 × cot α (1)
here,
Δa1: Change in axial preload clearance (mm)
Δr1: Change in radial radial clearance (mm)
(≒ Internal radial clearance change due to expansion and contraction of inner and outer rings)
α: Bearing contact angle (°)

Moreover, the initially set preload clearance Δa ′ (mm) after correction is calculated under the following conditions.
(Calculation condition)
Necessary preload load: 15000 N (theoretical preload clearance: Δa = −0.038 mm)
Initial fitting clearance between shaft and inner ring: 0.005 mm setting Initial fitting clearance between housing and outer ring: 0.005 mm setting

  In the case of the above conditions, the total amount of expansion and contraction of the inner and outer rings 11 and 12 is 0.010 mm due to the preload. That is, at the time of expansion and contraction of 0.010 mm, it becomes an interference fit and no further deformation occurs. Under the condition that the shaft 32 and the housing 31 are not inserted, the total expansion and contraction amount of the inner and outer rings 11 and 12 is 0.025 mm + 0.027 mm = 0.052 mm on the inner ring side + 0.027 mm.

Therefore, the correction amount (Δa1) of the preload clearance is
Δa1 = Δr1 × cot α = 0.010 × cot 35 ° = 0.0143 mm
From the above, the initial setting preload clearance is
Δa ′ (− 0.0523) = Δa (−0.038) + Δa1 (−0.0143) (mm).
With the above settings, it is possible to secure an assumed required preload (15000 N) after the bearing is assembled, and to prevent a decrease in rigidity.

  As described above, in the spindle turning device 30 of the present embodiment, the outer peripheral surface of the turning pedestal 32 that is the shaft and the inner peripheral surface of the inner ring 11 are preloaded on the spindle turning portion bearing 10 after being assembled. In the previous state, the clearance is fitted, and in the state where the preload is applied to the assembled bearing 10, the inner ring 11 is tightly fitted by contraction in the radial direction of the inner peripheral surface. Since it is not necessary to use a press or shrink fit when installing in the bearing, it can be easily assembled. Also, when the inner ring 11 is disassembled from the swivel base 32, the bearing 10 can be smoothly moved without applying a load. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. In addition, since the inner ring 11 and the turning pedestal 32 are closely fitted after the preload is applied, the occurrence of creep and the deterioration of rotational accuracy can be prevented.

  In the main spindle turning device 30 of the present embodiment, the inner peripheral surface of the base 31 that is a housing and the outer peripheral surface of the outer ring 12 are in a state before preload is applied to the main spindle turning portion bearing 10 after being assembled. When the outer ring 12 is assembled into the base 31, since it is a clearance fit, and in the state where the preload is applied to the bearing 10 after incorporation, the outer ring 12 is tightly fitted by radial expansion. Since there is no need to use a press or shrink fit, it can be easily assembled, and when the outer ring 12 is disassembled from the base 31, it can be carried out smoothly without applying a load to the bearing 10. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. Further, since the outer ring 12 and the base 31 are closely fitted after the preload is applied, the occurrence of creep and the deterioration of the rotation accuracy can be prevented.

  Further, according to the method of assembling the main spindle turning device 30 of the present embodiment, the inner peripheral surface of the base 31 that is the housing and the outer ring 12 and the outer peripheral surface of the turning base 32 that is the shaft and the outer peripheral surface of the inner ring 11. A step of incorporating the bearing 10 into the swivel base 32 and the base 31 with a clearance fit between at least one of the outer peripheral surface and a step of applying a predetermined preload to the bearing 10 after the assembling step. In the preload applying step, when a predetermined preload is applied to the bearing 10, the inner peripheral surface of the inner ring 11 is contracted in the radial direction with a tight fit between the outer peripheral surface of the swivel base 32 and the inner peripheral surface of the inner ring 11. And at least one of the radial expansion of the outer peripheral surface of the outer ring 12 that fits tightly between the inner peripheral surface of the base 31 and the outer peripheral surface of the outer ring 12, the swivel base 32 and the base 31 When installing the bearing 10, press or shrink fit There is no need to have easily built, also when disassembling the bearing 10, performed smoothly without burdening the bearing 10. Furthermore, the design around the bearing becomes easier as compared with the case of incorporating by tight fitting. Further, after the preload is applied, the bearing 10 and the swivel pedestal 32 / base 31 are tightly fitted, so that the occurrence of creep and the deterioration of the rotation accuracy can be prevented.

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. 12 (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.

  As another effect, the outer peripheral surface of the outer ring 12 expands or the inner peripheral surface of the inner ring 11 contracts when bearing preload is applied, so that the theoretical theoretical preload load (between the raceway grooves of the inner and outer rings 11 and 12 and the balls 13 is increased). (Calculated from elastic contact deformation) is not added to the bearing 10, and theoretical rigidity cannot be secured. By setting the fit to an appropriate value as in this embodiment, the expansion and contraction of the inner and outer rings 11 and 12 can be minimized, and the decrease in rigidity due to a decrease in the preload can be minimized. It becomes.

  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 this, 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 thousand N or more, so that the expansion and contraction deformation is also increased, and the above effect can be exhibited more.

(Modification)
As a modification of the present embodiment, a thin angular ball bearing 80 having a special dimension as shown in FIG. 13 may be used instead of the narrow angular ball bearing 14 used in the above embodiment. The angular ball bearing 80 has a contact angle between the inner ring 81 fitted on the swivel base 32, the outer ring 82 fitted on the base 31, and the raceways 81 a and 82 a of the inner ring 81 and the outer ring 82. And a plurality of balls 83 that are arranged to roll freely.

  As an index representing the thinness of the angular ball bearing, the radial cross-sectional thickness (so-called effective thickness: t) of the inner ring 81 (or outer ring 82) and the radial dimension (so-called “outer ring 82”) of the inner ring 81 (or outer ring 82). The effective thickness ratio: Y (= t / Dt), which is the ratio of the suburban diameter: Dt), is generally applied.

  Specifically, as shown in FIG. 13, when the inner ring effective wall thickness ratio Yi is the maximum wall thickness ti1, the minimum wall thickness ti2, and the inner ring inner diameter d of the inner ring 81, the effective wall thickness ti = ti1- (ti1- ti2) / 4 and the effective outer diameter Dit = d + 2ti (ti / Dit). Further, when the outer ring effective thickness ratio Yo is the maximum thickness to1, the minimum thickness to2, and the outer diameter Dt of the outer ring, the effective thickness to = to1- (to1-to2) / 3 and the effective outer diameter Dot. = It is expressed by a ratio (to / Dot) with Dt.

  When the effective wall thickness ratio Y (Yi, Yo) is small, the radial rigidity of the ring is small. Therefore, like the narrow angular ball bearing 14, the expansion and contraction of the inner and outer rings 81 and 82 when a large preload is applied. The amount increases. The calculation results of the expansion and contraction deformation of the inner and outer rings when a preload is applied to the standard-sized angular contact ball bearings shown in Table 2 and the special-dimension thin-walled angular contact ball bearings of the present invention (the present invention products B and C) are shown in FIG. 14 and FIG.

  As shown in FIG. 14 and FIG. 15, in a general application (machine tool spindle, etc.) and in a region where standard preload conditions are applied, the expansion / contraction amount between the products B and C of the present invention and the standard products A and B is small. Although a large difference is not recognized, super-high preload is applied because very high rigidity is required for the rotary table of the machine tool, the spindle turning mechanism, or the indirect part of the robot, the turning mechanism and the speed reduction mechanism. Often done. Under these conditions, the difference between the expansion and contraction amounts of both is very large.

  As shown in FIGS. 14 and 15, when a thin angular contact ball bearing (product of the present invention) with an effective thickness ratio Y of 5% or less is applied, the amount of expansion and contraction is very large. When set, the outer ring expansion amount is about 35 μm or more, and the inner ring contraction amount is 31 μm or more.

  Then, by incorporating the thin angular ball bearing 80 of the present modification into the shaft 32 and the housing 31 under the fitting conditions shown in Table 3, a clearance fit is applied before the preload is applied, and an interference fit is applied after the preload is applied. The effect of can be achieved.

  The accuracy P5 of the angular ball bearing 80 shown in Table 3 is a standard application condition, and the dimensional tolerance of the shaft 32 and the housing 31 is also a general selection condition (basic tolerance IT6: g6, H6). There is no problem in application. As described above, the thin-walled angular contact ball bearing 80 having a special dimension in which the effective thickness ratio of the present invention is 5% or less is used, and the proper bearing accuracy and the dimensional accuracy of the shaft / housing which are generally adopted are combined. Thus, the same effect as the main spindle turning device 30 of the first embodiment can be exhibited.

  As shown in FIGS. 14 and 15, in the case of the standard products A and B, the expansion amount of the outer ring at a preload 15000N is about 20 μm and the contraction amount of the inner ring is 20 μm, and the fitting range between the bearing and the shaft / housing is increased. Unless the thickness is 20 μm or less, the condition of “clearance fitting before preloading and tight fitting after preloading” according to the present invention cannot be satisfied. In order to achieve this condition, the shaft and housing accuracy needs to be less than the basic tolerance IT4 on two levels, and it is very difficult to ensure the processing accuracy, adding a precision processing step and greatly increasing the processing cost. A big problem such as an increase occurs.

  In addition, if the bearing has an effective thickness ratio Y of 5% or less, the effect of the present invention can be exhibited. However, if the effective thickness ratio Y is too small as in the ultrathin standard product shown in Table 2, (Outer ring effective wall thickness ratio Yo = 2.4, inner ring effective wall thickness ratio Yi = 2.8), the expansion / shrinkage amount at the preload 15000N becomes extremely large, and 100 μm (outer ring expansion amount 60 μm + inner ring shrinkage amount 55 μm) It will exceed.

  In other words, the ring rigidity of the inner and outer rings 81 and 82 is extremely reduced, and the ring deformation becomes large after being incorporated in the shaft 32 and the housing 31, resulting in problems such as dynamic torque fluctuation and rotational accuracy of the bearing 80 being deteriorated. . In particular, rotation accuracy becomes a problem in applications such as a rotary table and a turning mechanism of a machine tool. In addition, a stable torque characteristic is extremely required in the indirect part of the robot, which is also a problem. Therefore, in view of the above problems, the effective thickness ratio Y (outer ring effective thickness ratio Yo, inner ring effective thickness ratio Yi) is preferably 3% ≦ Y ≦ 5%.

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 may be used other than the application of the present embodiment, for example, a rotary table of a machine tool, a turning mechanism of a robot, a joint, a speed reduction mechanism, a rotating mechanism such as a drum of a printing machine, a direct motor rotation, etc. The same effect can also be exhibited by the support portion or the like. In particular, it is necessary to achieve both space saving and high rigidity in the rotary table of the machine tool, the spindle turning mechanism, the direct motor rotation support, the robot joint, the turning mechanism, and the speed reduction mechanism. If an angular ball bearing having a narrow width in the direction and a thin angular ball bearing are used, the amount of expansion and contraction of the race ring due to the preload is large, so that 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. Further, in the case of a combination bearing, it may be a two-row or more, for example, a three-row combination or a four-row combination angular ball bearing, if necessary.

  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 preload, in addition to a fixed position preload method using a combination of two or more rows of bearings, a constant pressure preload method that can add an appropriate preload load using a spring 70 as shown in FIG. Good. The preload application method and structure can be selected within the scope of the present invention in a timely manner.

  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 this 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 preloaded on the rolling bearing 10. In the state before being 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.

Further, in order to improve mechanical properties such as dimensional stability and wear resistance of the bearing, sub-zero treatment may be applied to at least one of the inner ring and the outer ring.
As a method of sub-zero treatment, for example, immediately after quenching, an atmosphere of about −150 ° C. is formed using liquid nitrogen, and tempering is performed after this sub-zero treatment. Then, sub-zero and tempering are repeated several times. In the sub-zero treatment using liquid nitrogen as the cooling medium, the number of repetitions may be at most about 3. Residual austenite (γR) in the structure is transformed into martensite by the sub-zero treatment. In addition, since the stabilization of the crystal grains is promoted, this improves the mechanical properties such as prevention of dimensional change with time and wear resistance.

  In the case of this bearing, since the axial width of the inner ring and the outer ring is narrow or the effective thickness is thin, there is a tendency that dimensional changes with time such as warpage and roundness failure tend to occur. Therefore, they can be suppressed by sub-zero treatment, especially when this bearing is used for a rotary table of a machine tool that requires bearing accuracy, a spindle turning mechanism, a rotary mechanism such as a drum of a printing machine, etc. In addition, it is possible to prevent malfunctions of equipment due to deterioration of bearing accuracy and to maintain the function for a long time.

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 shown in FIG. It is explanatory drawing for demonstrating the deformation amount of the radial direction of an inner ring | wheel. It is explanatory drawing for demonstrating the calculation method of the cross-sectional secondary moment of an inner ring | wheel. It is a graph which shows the relationship between a cross-sectional dimension ratio (B / H) and the deformation amount of the inner and outer ring | wheels of a radial direction. It is a graph which shows the relationship between a cross-sectional dimension ratio (B / H) and a cross-sectional secondary moment I. It is a graph which shows the relationship between a cross-sectional dimension ratio (B / H) and the deformation amount of the inner and outer ring | wheels of a radial direction. It is a graph which shows the relationship between a cross-sectional dimension ratio (B / H) and a cross-sectional secondary moment I. It is a graph which shows the relationship between the preload of this invention product, the radial direction shrinkage amount of an inner ring | wheel, and the radial direction expansion amount of an outer ring | wheel. It is a graph which compares and shows the relationship between the preload of this invention product and a conventional product, and the radial direction expansion amount of an outer ring | wheel. It is a graph which compares and shows the moment rigidity by the fitting conditions of this invention goods. (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. It is principal part sectional drawing which shows the thin-walled angular contact ball bearing of the modification of this invention. It is a graph which compares and shows the relationship between the preload of this invention product and a standard product, and the radial direction shrinkage | contraction amount of an inner ring | wheel. It is a graph which compares and shows the relationship between the preload of this invention product and a standard product, and the radial direction expansion amount of an outer ring | wheel. It is sectional drawing which shows the modification of the 2 row back combination angular contact ball bearing to which the constant pressure preload of this invention is provided. 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.

Explanation of symbols

10 Bearing for spindle turning part (rolling bearing)
11,81 Inner ring 12,82 Outer ring 13,83 Ball (rolling element)
14,80 Angular contact ball bearings 30 Spindle turning device (bearing device)
31 base (housing)
32 swivel base (axis)

Claims (5)

A bearing device comprising: a shaft, a housing, and an inner ring fitted onto the shaft, and an outer ring fitted inside the housing, and a rolling bearing to which a preload is applied after being incorporated into the shaft and the housing. ,
The rolling bearing has a plurality of balls arranged between the inner ring and the outer ring,
The inner ring effective wall thickness ratio Yi = ti when the maximum inner wall thickness ti1, the minimum wall thickness ti2, the inner ring inner diameter d, the effective wall thickness ti = ti1- (ti1-ti2) / 4, and the effective outer diameter Dit = d + 2ti. / Dit,
The outer ring effective thickness ratio when the maximum thickness to1, the minimum thickness to2, the outer ring outer diameter Dt, the effective thickness to = to1- (to1-to2) / 3, and the effective outer diameter Dot = Dt. Yo = to / Dot,
3% ≦ Yi, Yo ≦ 5% ball bearing,
A state in which 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 ball bearing after the assembly, and the preload is applied to the ball bearing after the assembly The bearing device according to claim 1, wherein the inner ring has an interference fit by contraction in a radial direction. A bearing device comprising: a shaft, a housing, and an inner ring fitted onto the shaft, and an outer ring fitted inside the housing, and a rolling bearing to which a preload is applied after being incorporated into the shaft and the housing. ,
The rolling bearing has a plurality of balls arranged between the inner ring and the outer ring,
The inner ring effective wall thickness ratio Yi = ti when the maximum inner wall thickness ti1, the minimum wall thickness ti2, the inner ring inner diameter d, the effective wall thickness ti = ti1- (ti1-ti2) / 4, and the effective outer diameter Dit = d + 2ti. / Dit,
The outer ring effective thickness ratio when the maximum thickness to1, the minimum thickness to2, the outer ring outer diameter Dt, the effective thickness to = to1- (to1-to2) / 3, and the effective outer diameter Dot = Dt of the outer ring. Yo = to / Dot,
3% ≦ Yi, Yo ≦ 5% ball bearing,
The inner peripheral surface of the housing and the outer peripheral surface of the outer ring are in a state in which a preload is applied to the ball bearing after the incorporation, and a preload is applied to the ball bearing after the assembly. The bearing device is characterized in that the outer ring has an interference fit by expansion in the radial direction.   2. The ball bearing according to claim 1, wherein 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. Or the bearing apparatus of 2. An assembly method for a bearing device, comprising: a shaft, a housing, and an inner ring fitted onto the shaft, and an outer ring fitted inside the housing, and a rolling bearing to which preload is applied after being assembled into the shaft and the housing. Because
In a state where at least one of the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring and at least one of the inner peripheral surface of the housing and the outer peripheral surface of the outer ring is fitted with clearance, the shaft and the housing are Incorporating a rolling bearing;
A step of applying a predetermined preload to the rolling bearing after the assembling step,
The rolling bearing has a plurality of balls arranged between the inner ring and the outer ring,
The inner ring effective wall thickness ratio Yi = ti when the maximum inner wall thickness ti1, the minimum wall thickness ti2, the inner ring inner diameter d, the effective wall thickness ti = ti1- (ti1-ti2) / 4, and the effective outer diameter Dit = d + 2ti. / Dit,
The outer ring effective thickness ratio when the maximum thickness to1, the minimum thickness to2, the outer ring outer diameter Dt, the effective thickness to = to1- (to1-to2) / 3, and the effective outer diameter Dot = Dt. Yo = to / Dot,
3% ≦ Yi, Yo ≦ 5% ball bearing,
In the preload application step, when the predetermined preload is applied to the ball bearing, a radial fit of the inner peripheral surface of the inner ring that fits between the outer peripheral surface of the shaft and the inner peripheral surface of the inner ring is performed. A method for assembling a bearing device, characterized in that at least one of contraction and expansion in the radial direction of the outer peripheral surface of the outer ring, which is tightly fitted between the inner peripheral surface of the housing and the outer peripheral surface of the outer ring, is generated. .   5. The ball bearing according to claim 4, wherein 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. A method for assembling the bearing device according to claim 1.

Images