JP2007192288A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing capable of achieving high speed operation and long service life by using only the grease sealed into the bearing, dispensing with maintenance, achieving stable supply of lubricating oil, and, in particular, achieving secure lubrication by causing a heat cycle in a grease sump actively even under continuous operation conditions over a long period of time. <P>SOLUTION: This rolling bearing has an inner ring 1, an outer ring 2, and a plurality of rolling bodies 3 provided between raceway surfaces 1a and 2a of these inner and outer rings 1, 2. A step face 2b being continuous with the raceway surface 2a is provided in the direction in which it leaves the rolling body 3 on a non-rotating fixed side bearing ring 2 among the inner ring 1 and the outer ring 2 being the bearing rings. A clearance forming piece 7 whose tip faces the step face 2b through a clearance 15 is provided. The grease sump 9 communicating with the clearance 15 is provided. A grease sump cooling liquid circulating passage 36 for circulating cooling liquid for cooling a member 22 coming into contact with the fixed side bearing ring 2 around the grease sump 9 is provided to give a heat cycle for raising and lowering temperature to the grease sump 9 by the cooling liquid flowing in the grease sump cooling liquid circulating passage 36. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing having a lubrication function for grease lubrication of a machine tool main shaft or the like.

  As a lubrication method for machine tool spindle bearings, grease lubrication that can be used maintenance-free, air-oil lubrication in which lubricating oil is mixed with carrier air and oil is injected into the bearing from the nozzle, jet that injects lubricating oil directly into the bearing There are methods such as lubrication. In recent machine tools, in order to increase machining efficiency, there is a tendency for higher speed, and lubrication of main shaft bearings is also relatively inexpensive and air-oil lubrication that can be speeded up easily is often used. However, this air oil lubrication method has a problem from the viewpoint of cost, noise, energy saving, and resource saving because it requires an air oil supply device as ancillary equipment and requires a large amount of air. There is also a problem of deteriorating the environment due to the scattering of oil. In order to avoid these problems, recently, speeding up by grease lubrication has begun to attract attention, and requests have been increasing.

  Since grease lubrication is performed only with the grease enclosed at the time of bearing assembly, high-speed operation may lead to premature seizure due to deterioration of the grease due to bearing heat generation and oil film breakage on the raceway surface, especially the inner ring. . In particular, it is difficult to guarantee the grease life in a high-speed rotation region where the dn value exceeds 1 million (bearing inner diameter mm × rotational speed rpm).

New proposals have been introduced as a means of extending the life of grease. For example, there is a proposal (Patent Document 1) aiming at high speed and long life by providing a grease reservoir on the outer ring raceway surface. In addition, there is a proposal (Patent Document 2) in which a bearing is properly lubricated and lubricated by a grease replenishing device provided outside the spindle.
Japanese Patent Laid-Open No. 11-108068 JP 2003-113998 A

However, the technologies of the above proposed examples are not satisfactory in consideration of the number of rotations used (> dn value 1.5 million) equivalent to air oil lubrication and maintenance-free.
Therefore, by developing the technique of Patent Document 1, a fixed-side race ring (for example, an outer ring) is provided with a stepped surface that follows the raceway surface in a direction away from the rolling element, and the tip faces the stepped surface via a gap and has a peripheral wall. A gap forming piece for forming a flow path between the stationary side ring and a grease reservoir communicating with the flow path is provided, and a gap between the stepped surface and the tip of the gap forming piece is defined as a grease base. It was considered that the oil could be held at all times, and the base oil could be supplied to the raceway surface by the volume expansion of the base oil caused by the rotation of the bearing and the air flow near the raceway surface.
According to this rolling bearing, when the bearing is stopped, the grease base oil moves from the flow path to the gap due to the thickener in the grease and the capillary phenomenon of the gap, and the gap between the capillary phenomenon and the oil surface tension The base oil is kept oily. When the bearing is operated, the base oil stored in the clearance is discharged from the clearance due to the volume expansion caused by the temperature rise of the fixed-side raceway and the air flow generated by the revolution and rotation of the rolling elements. It moves while adhering to the raceway surface of the raceway and is continuously supplied to the rolling element contact portion.
However, in the structure in which the base oil is moved to the gap only by the capillary phenomenon in the thickener and the gap as described above, the ability to move the base oil is not sufficient, and it cannot be said that the lubrication of the bearing is necessarily sufficient. .

Therefore, in a rolling bearing having such a structure, the base oil separated from the grease passes through the gap and enters the raceway surface of the stationary side raceway due to the pressure fluctuation due to the heat cycle in the grease reservoir accompanying the repeated operation stop and restart. It was considered to set the size of the gap so as to be discharged.
When the gap is set in this way, when the temperature of the grease reservoir rises, the base oil in the grease inside the sealed grease reservoir becomes thicker due to the difference in expansion coefficient between the thickener and the base oil in the grease. In addition, the base oil is surely moved to the gap by the pressure fluctuation of the grease reservoir due to the heat cycle, and is further pushed out and supplied to the raceway surface.
However, in an actual machine tool using this rolling bearing, continuous operation for a long period of time is not uncommon, and tool replacement is completed in about several seconds, so the above-described heat cycle may not exist substantially. As a result, the pressure in the grease reservoir that has risen after the start of operation decreases at the same time as the base oil is discharged, and eventually becomes atmospheric pressure, and the discharge of the base oil stops despite the operation.

  The object of the present invention is to eliminate these problems. The grease can be actively heat-generated even under long-term continuous operation conditions to ensure lubrication and enclosed in a bearing. The purpose of this invention is to provide a rolling bearing that uses only the grease that has been used to achieve high speed, long life, maintenance-free operation, and stable supply of lubricating oil.

The rolling bearing according to the present invention is a rolling bearing having an inner ring, an outer ring, and a plurality of rolling elements interposed between the raceways of the inner and outer rings. A stepped surface following the raceway surface is provided in a direction away from the rolling element, a gap forming piece whose tip faces the stepped surface through a gap is provided, a grease reservoir communicating with the gap is provided, and the fixed side raceway is in contact A grease pool coolant circulation path for circulating a coolant for cooling the member around the grease reservoir is provided, and the grease flowing through the grease pool coolant circulation path gives a heat cycle of temperature rise and fall to the grease reservoir. It is what I did. The fixed-side raceway may be an outer ring, for example, and the member in contact with the fixed-side raceway may be a housing for installing the outer race, for example.
The rolling bearing having this configuration is used by filling a grease reservoir with grease. An appropriate amount of grease as an initial lubricating oil is applied to the bearing raceway surface. When an operation of a machine tool or the like using this bearing is performed, the base oil separated from the grease due to an increase in temperature and pressure in the sealed grease reservoir passes through the gap between the step surface and the gap forming piece. Extruded to the raceway surface. In addition, there is an effect due to capillary action and surface tension in the gap, and this also causes the base oil to be discharged onto the outer ring raceway surface, thereby further ensuring lubrication. At this time, even if there is no operation / pause cycle of the equipment using the bearing, and the continuous operation state, the flow of the coolant circulating around the grease reservoir is interrupted by the grease reservoir coolant circulation path, The grease reservoir can be actively given a heat cycle of temperature rise and fall. Thereby, the operation in which the base oil separated from the grease due to the pressure fluctuation is discharged to the outer ring raceway surface through the gap is repeated. For this reason, supply of lubricating oil is performed reliably. In this way, even under long-term continuous operation conditions, only the grease enclosed in the bearing can be used to increase the speed, extend the service life, eliminate maintenance, and provide a stable supply of lubricating oil.

  In this invention, the rolling bearing may be an angular ball bearing that supports a machine tool spindle. When the angular ball bearing is provided, the stepped surface is provided on the side opposite to the direction in which the contact angle is generated, so that the stepped surface is more easily disposed directly below the rolling element. The step surface can be brought close to the center of the rolling element, and lubricating oil can be replenished from the step surface to the raceway more efficiently.

  In this invention, the rolling bearing may be a cylindrical roller bearing or a tapered roller bearing that supports the main spindle of the machine tool.

  A rolling bearing according to the present invention is a rolling bearing having an inner ring, an outer ring, and a plurality of rolling elements interposed between the raceways of the inner and outer rings. A step surface following the raceway surface is provided in a direction away from the rolling element, a gap forming piece whose tip faces the step surface through a gap is provided, a grease reservoir communicating with the gap is provided, and the fixed side raceway is in contact A grease pool coolant circulation path for circulating a coolant for cooling the member around the grease reservoir is provided, and the grease flowing through the grease pool coolant circulation path gives a heat cycle of temperature rise and fall to the grease reservoir. As a result, using only the grease sealed in the bearing, speeding up and long life, maintenance-free, and stable supply of lubricating oil are possible. There, in particular, actively in long-term continuous operation conditions by causing a heat cycle grease reservoir, it is possible to surely perform the lubrication.

  A first embodiment of the present invention will be described with reference to FIGS. In this embodiment, an example of a rolling bearing incorporated in a spindle unit of a machine tool spindle is shown. In FIG. 1, this rolling bearing has a plurality of rolling elements 3 interposed between raceways 1a and 2a of an inner ring 1, an outer ring 2, and inner and outer rings 1 and 2, and a grease pool forming component 6 and a gap forming piece. 7. The plurality of rolling elements 3 are held by a cage 4, and one end of the bearing space between the inner and outer rings 1 and 2 is sealed with a seal 5. The seal 5 prevents leakage of grease sealed inside the bearing to the outside. This rolling bearing is an angular ball bearing, the seal 5 is provided at the end on the back side of the bearing, and the grease reservoir forming component 6 and the gap forming piece 7 are provided on the front side of the bearing. On the front side of the bearing, the grease reservoir forming part 6 also serves as a seal, and grease leakage from the front side of the bearing is prevented. In the figure, the crossed hatched portions indicate portions filled with grease. The inner ring 1 of the rolling bearing is fitted to a main shaft (not shown) in the drawing so as to be rotatable, and the outer ring 2 is fixedly supported in the fitted state on the inner periphery of the housing 22 in the spindle unit.

  On the outer ring 2 serving as a fixed-side raceway, a step surface 2b following the raceway surface 2a follows the outer ring front side away from the rolling elements 3, that is, the edge on the opposite side to the direction in which the contact angle occurs on the raceway surface 2a. Is provided. The step surface 2b is a surface that extends from the raceway surface 2a to the outer diameter side and faces the outer ring front side. In this embodiment, the step surface 2b is a front-side width surface. However, the outer ring 2 may have a shape in which a front-side inner diameter surface portion continues from the step surface 2b.

  The grease reservoir forming component 6 is a ring-shaped component having a grease reservoir 9 formed therein, and is provided in contact with the front side width surface of the outer ring 2. In this example, the grease reservoir forming component 6 is fitted to the outer ring positioning spacer 10 provided in contact with the front-side width surface (here, the step surface 2b) of the outer ring 2, and the inner diameter surface of the outer ring positioning spacer 10. It consists of an outward groove-shaped grease reservoir forming component main body 11. An internal space sandwiched between the outer ring positioning spacer 10 and the grease reservoir forming component main body 11 is a grease reservoir 9.

  A sealing material (not shown) is interposed between the outer diameter surface of the side wall portion 11a of the grease reservoir forming component main body 11 and the inner diameter surface of the outer ring positioning spacer 10 opposed thereto, or the grease reservoir forming component main body 11 and The outer ring positioning spacer 10 is bonded with an adhesive. A sealing material (not shown) is also interposed between the mating surfaces of the outer ring positioning spacer 10 and the outer ring 2. These sealing materials prevent grease leakage.

  The gap forming piece 7 is disposed along the inner diameter surface 10a of the outer ring positioning spacer 10, and the tip faces the step surface 2b. As shown in an enlarged view in FIG. It is a ring-shaped member that forms the flow path 14 and the gap 15. The gap forming piece 7 is formed integrally with the grease reservoir forming component main body 11. In other words, the grease reservoir forming component main body 11 extends integrally from the outer diameter end portion of the side wall portion 11b on the bearing adjacent side.

The flow path 14 is formed by the peripheral wall of the tip 7a of the gap forming piece and the inner diameter surface 10a of the outer ring positioning spacer 10 facing this. The gap forming piece 7 has a tip portion 7a extending to a position close to the step surface 2b of the outer ring 2, and an axial direction between the end surface of the tip portion 7a of the gap forming piece and the outer ring step surface 2b facing it. The gap 15 having a minute gap amount δ is formed. The gap 15 communicates with the flow path 14 and opens at the edge of the outer ring raceway surface 2a. The gap amount δ of the gap 15 is set to 0.05 to 0.1 mm.
The inner diameter surface following the end surface of the gap forming piece tip 7a is a tapered surface 7aa close to the rolling element 3 so that the lubricating oil can easily accumulate between the tapered surface 7aa and the rolling element 3. The distance d between the tapered surface 7aa and the rolling element 3 is preferably a minimal gap of 0.2 mm or less with a size that allows oil attached to the tapered surface 7aa to transfer to the surface of the rolling element 3. The base portion 7b of the gap forming piece 7 has a smaller diameter than the distal end portion 7a. A portion surrounded by the outer diameter surface of the base portion 7 b and the inner diameter surface 10 a of the outer ring positioning spacer 10 is a part of the grease reservoir 9, and the flow path 14 communicates with the grease reservoir 9.

A spiral coolant passage 33 is provided in the housing 22 that fixedly supports the outer ring 2 of the rolling bearing. The coolant is supplied to the inlet 33a of the coolant passage 33 from the coolant recovery / cooling device 34 shown in FIG. 1 through the supply path through which the pump 35 is interposed. The coolant used for cooling the housing 22 is the coolant passage. The coolant is returned from the outlet 33 b of 33 through the recovery path to the coolant recovery / cooling device 34 and is circulated and supplied to the coolant passage 33 again.
A spiral coolant passage 37 is also provided on the outer periphery of the outer ring positioning spacer 10, and is supplied to the coolant passage inlet 33a via a coolant inlet 38 branched from the inlet 33a of the coolant passage 33. A part of the coolant to be supplied is also supplied to the coolant passage 37. A sealing material 16 such as an O-ring is interposed between the inner peripheral surface of the housing 22 and both axial positions of the region where the coolant passage 37 is disposed on the outer peripheral surface of the outer ring positioning spacer 10. Prevention of coolant leakage. Further, the housing 22 is provided with a cooling liquid outlet 39 for returning the cooling liquid having passed through the cooling liquid passage 37 to the cooling liquid recovery / cooling device 34, and the cooling liquid exiting the cooling liquid outlet 39 is interposed by an electromagnetic valve 40. The coolant is returned to the coolant recovery / cooling device 34 via the recovery path. The coolant passage 37, coolant inlet 38, coolant outlet 39, solenoid valve 40, etc. constitute a grease reservoir coolant circulation path 36 that circulates a portion of the coolant that cools the housing 22 around the grease reservoir 9. Is done. The grease pool coolant circulation path 36 is configured to give the grease pool 9 a heat cycle in which the temperature rises and falls by the opening / closing control of the solenoid valve 40.

The operation of the above configuration will be described. When the bearing is assembled, the grease reservoir 9 and the flow path 14 are filled with grease. An appropriate amount of grease for initial lubrication is applied to the bearing raceway surface.
When the operation of the machine tool is started, immediately after the start of operation, in the grease stored in the grease reservoir 9 that is sealed except for the gap 14, the base oil and the thickener differing in expansion rate due to the temperature rise accompanying the start of operation. Is separated. At the same time, the internal pressure of the sealed grease reservoir 9 increases. Due to this internal pressure, the separated base oil is discharged from the gap 14 toward the raceway surface 2 a of the outer ring 2. When the temperature rises and reaches a steady state, the internal pressure increase factor disappears, so that the internal pressure gradually decreases in parallel with the base oil discharge, and the base oil discharge amount per unit time also decreases. Here, when the solenoid valve 40 of the grease pool coolant circulation path 36 is opened, the coolant inlet path 38 → the coolant path 37 → the coolant outlet 39 → the coolant recovery / cooling device 34 → the pump 35 → the coolant inlet 38 path. Then, the coolant begins to circulate, and the outer ring positioning spacer 10 is cooled. As a result, the temperature and pressure in the grease reservoir 9 are rapidly reduced, and the base oil discharge amount per unit time is further reduced.
Thereafter, when the solenoid valve 40 is closed and the flow of the coolant in the spiral coolant passage 37 is stopped, the temperature of the grease reservoir 9 starts to rise, and the base oil is again applied to the outer ring raceway surface 2a by the same mechanism as described above. It will be discharged. Thereafter, the pressure fluctuation in the grease reservoir 9 is repeated by such a temperature increase and decrease heat cycle, and the base oil separated from the grease is surely moved to the gap 14 and repeatedly on the raceway surface 2a of the outer ring 2. Supplied.
In this embodiment, since the gap amount δ of the gap 15 is set to 0.05 to 0.1 mm, a practically sufficient base oil discharge amount can be obtained. This gap amount δ is also an appropriate value from the viewpoint of workability of actual clearance 15 and clearance adjustment.

  In addition to the base oil discharging action by the heat cycle, a base oil discharging action by the capillary action shown below is also added. That is, when the bearing is stopped, the grease base oil moves from the flow path 14 to the gap 15 due to the thickener in the grease and the capillary phenomenon of the gap 15, and the capillary action and the surface tension of the oil combine to form the gap 15. The base oil is kept oily. When the bearing is operated, the base oil stored in the clearance 15 is discharged from the clearance 15 due to the volume expansion caused by the temperature increase of the outer ring 2 generated by the operation and the air flow generated by the revolution and rotation of the rolling element 3, and the outer ring It moves while adhering to the two raceway surfaces 2a and is continuously supplied to the rolling element contact portion.

  As described above, in this rolling bearing, the coolant flowing through the grease pool coolant circulation path 36 gives the grease pool 9 a heat cycle in which the temperature rises and falls, thereby causing a pressure fluctuation in the grease pool 9 and the grease. Since the base oil separated from the oil is repeatedly discharged to the raceway surface 2a of the outer ring 2 through the gap 15, the lubricating oil is reliably supplied. In addition, since the base oil is discharged to the raceway surface 2a of the outer ring 2 also by the above-described capillary phenomenon in the gap 15, lubrication is further ensured. As a result, using only the grease sealed in the bearing, it is possible to increase the speed, extend the service life, eliminate maintenance, and supply a stable lubricant.

  In the case of this embodiment, since the rolling bearing is an angular ball bearing, the stepped surface 2b of the outer ring 2 is provided on the side opposite to the direction in which the contact angle is generated, whereby the stepped surface 2b can be more easily disposed directly below the rolling element 3. Become. Since the step surface 2b can be brought close to the center of the rolling element 3, the lubricating oil can be more efficiently supplied from the step surface 2b to the outer ring raceway surface 2a.

  As a means for giving a heat cycle to the grease reservoir 9, a coolant supply means such as a coolant recovery / cooling device 34 and a pump 35 is necessary. However, since the coolant supply means for cooling the housing 22 is also used, Can be avoided and cost can be reduced. Built-in motors are often used to drive the spindles of recent machine tools, and because of the influence of heat generation, a cooling spiral groove is provided in the motor housing and the outer periphery of the bearing, and cooling is performed through the coolant. (So-called outer cylinder cooling). Therefore, a coolant passage 37 that also has a spiral groove is provided on the outer diameter side of the grease reservoir 9, and the coolant for cooling such as a housing is allowed to pass therethrough, so that the temperature of the grease reservoir 9 raised by the operation of the machine tool is increased. Lowering and giving a heat cycle can be done easily.

  FIG. 3 shows an example of a built-in motor type machine tool spindle device using the rolling bearing of the above embodiment. In the spindle device for machine tools, two of the rolling bearings are used as a back surface combination. The two rolling bearings 23 and 24 rotatably support both ends of the main shaft 21 within the housing 22. The inner ring 1 of each rolling bearing 23, 24 is positioned by an inner ring positioning spacer 26 and an inner ring spacer 27, and is fastened and fixed to the main shaft 21 by an inner ring fixing nut 29. The outer ring 2 is positioned and fixed in the housing 22 by an outer ring positioning spacer 10, an outer ring spacer 30 and an outer ring presser cover 31. The housing 22 is formed by fitting the housing inner cylinder 22A and the housing outer cylinder 22B, and a cooling fluid passage 33 for cooling is provided in the fitting portion. The coolant passage 33 is also provided in the outer peripheral portion of the motor 40 in the housing 22.

  The spindle 21 is provided with a chuck (not shown) for detachably attaching a tool or a work (not shown) at the front end 21a, and a rotor 40a of the motor 40 is provided at the rear end 21b. Yes. The motor 40 is built in the housing 22 and includes a stator 40b such as a coil installed in the housing 22 and the rotor 40a. The motor 40 may be installed outside the housing 22 and connected to the main shaft 21 via a rotation transmission mechanism (not shown). This spindle apparatus can be applied to various machine tools such as a machining center, a lathe, a milling machine, and a grinding machine.

  According to the spindle device of this configuration, the effects of stable supply of lubricant, high speed, long life, and maintenance-free operation in the rolling bearings 23 and 24 of this embodiment are effectively exhibited.

  FIG. 4 shows another embodiment of the present invention. In this embodiment, the configuration of the grease reservoir forming component 6 in the first embodiment shown in FIGS. 1 and 2 is applied to a cylindrical roller bearing. The grease reservoir forming component 6 is provided adjacent to both sides of the outer ring 2 in the axial direction. Other configurations are the same as those of the first embodiment shown in FIGS.

  In the case of this embodiment, grease base oil can be supplied from the grease reservoirs 9 on both sides to the outer ring raceway surface 2a. In the case of a cylindrical roller bearing, the roller serving as the rolling element 3 has a certain length. Therefore, it is preferable to supply the base oil of grease from both sides in terms of improving lubricity because it can be supplied in the axial direction without deviation. Thereby, speed-up, long life, and maintenance-free can be further improved. Also in the case of this cylindrical roller bearing, as in the case of the angular ball bearing of the first embodiment shown in FIGS. Long life and maintenance free.

  FIG. 5 shows still another embodiment of the present invention. In this embodiment, the configuration of the grease reservoir forming component 6 in the first embodiment shown in FIGS. 1 and 2 is applied to a tapered roller bearing. The grease pool forming component 6 is provided adjacent to the side where the outer ring raceway surface 2a in the axial direction of the outer ring 2 has a large diameter. Other configurations are substantially the same as those of the first embodiment shown in FIGS.

  In the case of this embodiment, the base oil of the grease supplied from the grease reservoir 9 to the large-diameter side of the outer ring raceway surface 2a inevitably slips, and the roller large end face and the inner ring that are liable to cause lubrication in a tapered roller bearing. Since it is reliably guided between the large brim surfaces, the lubricity can be improved. Thereby, speed-up, long life, and maintenance-free can be further improved. In the case of this tapered roller bearing, as in the case of the angular ball bearing of the first embodiment shown in FIG. 1 and FIG. Long life and maintenance free.

It is a fragmentary sectional view of the rolling bearing which concerns on 1st Embodiment of this invention. It is a partial expanded sectional view of the rolling bearing. It is sectional drawing of the spindle apparatus for machine tools using the rolling bearing. It is a fragmentary sectional view of the rolling bearing which concerns on other embodiment of this invention. It is a fragmentary sectional view of the rolling bearing which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner ring 1a ... Raceway surface 2 ... Outer ring 2a ... Raceway surface 3 ... Rolling body 2b ... Step surface 7 ... Gap formation piece 9 ... Grease pool 10 ... Outer ring positioning spacer 15 ... Gap 22 ... Housing 36 ... Grease pool Coolant circulation Road

Claims (5)

  In a rolling bearing having an inner ring, an outer ring, and a plurality of rolling elements interposed between the raceways of the inner and outer rings, a stepped surface following the raceway is provided on the stationary raceway that does not rotate among the inner ring and outer ring that are raceways. Provided in a direction away from the rolling element, provided with a gap forming piece with the tip facing the stepped surface via a gap, provided with a grease reservoir communicating with the gap, and provided with a coolant for cooling the member in contact with the stationary side race A rolling bearing provided with a grease pool coolant circulation path that circulates around the grease pool, and that provides a heat cycle of temperature rise and fall to the grease pool by the coolant flowing through the grease pool coolant circulation path.   The rolling bearing according to claim 1, wherein the fixed side race is an outer ring, and a member in contact with the fixed side race is a housing in which the outer ring is installed.   The rolling bearing according to claim 1, wherein the rolling bearing is an angular ball bearing that supports a main spindle of a machine tool.   The rolling bearing according to claim 1 or 2, wherein the rolling bearing is a cylindrical roller bearing that supports a main spindle of a machine tool.   The rolling bearing according to claim 1, wherein the rolling bearing is a tapered roller bearing that supports a machine tool main shaft.

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