JP2015102213A - Bearing device and spindle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device and a spindle device capable of achieving long life of a grease even with a comparatively simple configuration.SOLUTION: A pair of spacer internal space pieces S2a, S2b which are configured by being surrounded by an inner peripheral surface of an outer ring spacer 30, a wall part 32, an outer peripheral surface of an inner ring spacer piece 21 and a flange part 22 are partitioned by the wall part and formed. On an inner peripheral surface of each outer ring spacer piece 31 in the pair of spacer internal space pieces S2a, S2b, a grease G2 is sealed. In a bearing device 1: between the wall part 32 and the outer peripheral surface of the pair of inner ring spacer pieces 21, a small diameter labyrinth L1 is formed for communicating the pair of spacer internal space pieces; between the flange part 22 and the inner peripheral surface of the outer ring spacer 30, a large diameter labyrinth L2 is formed for communicating the spacer internal space pieces S2a, S2b and a bearing internal space S1; and at the outer ring spacer 30, an air hole 34 is provided for communicating the small diameter labyrinth L1 and an outer space and supplying air.

Description

  The present invention relates to a bearing device and a spindle device.

  A rotating shaft of a spindle device applied to a machine tool or the like rotates at a high speed to perform cutting or grinding of a workpiece. The speedup of spindles for machine tools has been remarkably developed, and oil mist lubrication and oil-air lubrication have been the mainstream as a lubrication method for enabling speedup of the spindle. However, in recent years, there has been a trend toward environmental measures, energy savings, and resource savings. In addition to the need for environmental considerations due to noise and oil scattering, a large amount of air is required, and an oil mist supply device In addition, there is a disadvantage in terms of cost because ancillary facilities such as oil and air supply devices are required.

  In order to avoid these problems, grease lubrication has begun to attract attention again. Grease lubrication is performed with the base oil of the grease enclosed when the bearing is assembled, but the amount of base oil necessary for bearing lubrication is limited and depends on the lubrication life. For this reason, there is a measure to increase the amount of grease sealed in the bearing. However, this increases the viscous resistance, so if the bearing is used at high speed, the heat generated by the bearing will increase. It may lead to burn-in. Even if the rotational speed is not high, if excessive grease is filled, the running-in time becomes longer, and it takes time to return to the production line after replacing the main bearing, which affects production efficiency.

  Therefore, it is conceivable to apply the grease retaining component of the rolling bearing described in Patent Document 1. The grease reservoir component is disposed adjacent to the outer ring, which is a fixed ring, with respect to 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. Further, the grease reservoir component has an annular container portion in which the inside is a grease reservoir, and an annular in-bearing insertion portion that protrudes from the container portion and is inserted to the vicinity of the raceway surface of the outer ring. The inside of the bearing insertion portion serves as a grease flow path, and has a slit-like grease base oil bleeding port at the tip. The grease base oil oozing port is sealed with a removable sealing member.

  When the grease reservoir part is mounted on the rolling bearing, the base oil separated from the grease is removed from the grease in the bearing insert due to the pressure fluctuation due to the heat cycle in the grease reservoir due to repeated stoppage and restart of the rolling bearing. Lubricating oil is supplied by being discharged from the base oil bleeding port onto the raceway surface of the outer ring. As a result, the bearing speed is increased, the service life is extended, and maintenance is free.

JP 2008-240828 A

  However, as described above, the grease reservoir component described in Patent Document 1 has an in-bearing insertion portion that protrudes from the container portion and is inserted to the vicinity of the raceway surface of the outer ring, and has a complicated structure. It was inconvenient to handle the grease reservoir alone.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a bearing device and a spindle device capable of extending the life of grease while having a relatively simple configuration. .

The above object of the present invention can be achieved by the following constitution.
(1) An inner ring that is a rotating ring, an outer ring that is a fixed ring, a plurality of balls disposed between raceways of the inner ring and the outer ring, and a cage that holds the plurality of balls in a freely rolling manner. A pair of angular contact ball bearings arranged coaxially,
An inner ring spacer that is disposed between the pair of inner rings and rotates together with the inner ring;
An outer ring spacer disposed between the pair of outer rings;
A bearing device comprising:
Between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, a bearing internal space is formed,
Grease is enclosed in the inner peripheral surface of the outer ring in the bearing internal space,
The outer ring spacer is provided with a wall portion projecting radially inward at an axially intermediate portion,
The inner ring spacer is composed of a pair of inner ring spacer pieces that abut in the axial direction,
Each of the pair of inner ring spacer pieces is provided with a flange projecting radially outward at each axial end,
A pair of spacer inner space pieces surrounded by the inner peripheral surface of the outer ring spacer, the wall portion, the outer peripheral surface of the inner ring spacer piece, and the flange are separated by the wall portion. Formed,
Grease is sealed on the inner peripheral surface of each outer ring spacer in the pair of spacer inner space pieces,
Between the wall and the outer peripheral surface of the pair of inner ring spacer pieces, a small-diameter labyrinth that communicates the pair of spacer inner space pieces is formed,
A large-diameter labyrinth that connects the spacer inner space piece and the bearing inner space is formed between the flange and the inner peripheral surface of the outer ring spacer,
The bearing device, wherein the outer ring spacer or the inner ring spacer is provided with an air hole that communicates the small-diameter labyrinth with the external space to supply air.
(2) The bearing device according to (1), wherein a counter bore is formed on an inner peripheral surface of the outer ring on an outer side in the axial direction than the raceway surface.
(3) The bearing device according to (1) or (2), wherein the large-diameter labyrinth has a tapered shape having a diameter that increases from the spacer inner space piece toward the bearing inner space.
(4) In any one of (1) to (3), the grease enclosed in the inner peripheral surface of the outer ring and / or the inner peripheral surface of the outer ring spacer is a gel grease. The bearing device described.
(5) a rotating shaft to which a machining tool is attached at one end in the axial direction;
A housing that rotatably supports the rotating shaft via the bearing device according to any one of (1) to (4);
A spindle apparatus comprising:

When the inner ring and inner ring spacer rotate at high speed, the labyrinth generates a circumferential air flow due to the peripheral speed of the outer peripheral surface of the inner ring spacer. In this case, the higher the peripheral speed, the more negative pressure action occurs. Cheap. Here, a small-diameter labyrinth that communicates the pair of spacer inner space pieces is formed between the wall portion and the outer peripheral surface of the pair of inner ring spacer pieces, and between the collar portion and the inner peripheral surface of the outer ring spacer piece. A large-diameter labyrinth that connects the spacer internal space piece and the bearing internal space is formed, and the pressure of the large-diameter labyrinth (axially outer side) <the small-diameter labyrinth (axially intermediate side). Therefore, the air supplied from the external space through the air holes flows in the spacer inner space piece from the small-diameter labyrinth (axially intermediate side) toward the large-diameter labyrinth (axially outer side). By this air flow, the base oil component of the grease sealed in the inner peripheral surface of the outer ring spacer can be moved to the bearing internal space side through the grease oil passage. As a result, the life of the grease can be extended, and it becomes possible to cope with further high-speed rotation.
Further, in the pair of spacer inner space pieces separated by the wall portion, grease is sealed on the inner peripheral surface of the outer ring spacer, so the grease sealed in one spacer inner space piece is used as one angular ball. It is possible to supply grease to the bearing and to supply grease to the other angular ball bearing with the grease sealed in the other spacer inner space piece. Thereby, it becomes possible to supply grease base oil appropriately to each of the pair of angular ball bearings, and it is possible to prevent the supply of grease base oil to one of the angular ball bearings from being insufficient.
Further, the outer ring spacer or the inner ring spacer is provided with an air hole for supplying air by communicating the small-diameter labyrinth with the outer space of the bearing device. Forcibly or continuously feeding air makes it easier to feed the grease base oil into the bearing internal space. Furthermore, by controlling the air pressure according to various conditions such as the rotation speed and temperature of the bearing, it is possible to supply proper grease.

It is sectional drawing of the bearing apparatus which concerns on one Embodiment of this invention. It is a partial cross section figure of the spindle apparatus provided with the bearing apparatus of FIG. It is sectional drawing of the bearing apparatus which concerns on a modification.

  Hereinafter, a bearing device according to an embodiment of the present invention will be described in detail based on the drawings.

  The bearing device 1 of the present embodiment includes an inner ring 11 that is a rotating wheel, an outer ring 12 that is a fixed ring, a plurality of balls 13 disposed between the raceways 11a and 12a of the inner ring 11 and the outer ring 12, and a plurality of balls. And a pair of angular ball bearings 10 that are coaxially arranged in a rear combination. The bearing device 1 is disposed between the pair of inner rings 11 and rotates with the inner ring 11, and an annular inner ring spacer 20, and an annular outer ring spacer 30 disposed between the pair of outer rings 12, Is provided.

  A counterbore 12b is formed on the inner circumferential surface of the outer ring 12 on the axially outer side of the raceway surface 12a (right and left sides in FIG. 1; directions away from the outer ring spacer 30). A flat surface 12c is formed on the inner side (in the direction close to the outer ring spacer 30 in FIG. 1).

  A bearing internal space S1 is formed between the inner peripheral surface of the outer ring 12 and the outer peripheral surface of the inner ring 11, and grease G1 is provided on the inner peripheral surface (counter bore 12b and plane 12c) of the outer ring 12 in the bearing inner space S1. Is enclosed. In view of the balance between the temperature rise characteristics during high-speed rotation and the long grease life, it is usually desirable to enclose approximately 10 to 20% of the grease with respect to the volume of the bearing internal space S1.

  The outer ring spacer 30 has a wall portion 32 projecting radially inward at the axially intermediate portion.

  The inner ring spacer 20 includes a pair of inner ring spacer pieces 21 that are in contact with each other in the axial direction in order to facilitate assembly. Each of the pair of inner ring spacer pieces 21 has a flange portion 22 formed radially outward at an axially outer end portion.

  The inner circumferential surface of the outer ring spacer 30, the wall portion 32, the outer circumferential surface of the inner ring spacer piece 21, and the spacer inner space pieces S 2 a and S 2 b surrounded by the flange portion 22 are separated by the wall portion 32. A pair is formed. The pair of spacer inner space pieces S2a and S2b constitute a spacer inner space S2. Moreover, grease G2 is enclosed with the inner peripheral surface of the outer ring spacer 30 in the spacer inner space pieces S2a and S2b.

  A small-diameter labyrinth L1 is formed between the wall portion 32 and the outer peripheral surface of the pair of inner ring spacer pieces 21 so as to communicate the pair of spacer inner space pieces S2a, S2b in the axial direction. A large-diameter labyrinth L2 is formed between the inner peripheral surface 30 and the spacer inner space pieces S2a, S2b and the bearing inner space S1 in the axial direction.

  The outer ring spacer 30 is provided with an air hole 34 that communicates the inner circumferential surface of the wall portion 32 in the radial direction from the outer circumferential surface thereof to communicate the small-diameter labyrinth L1 and the outer space of the bearing device 1. Air can be forced into the air holes 34 intermittently or continuously.

  In the bearing device 1 configured as described above, when the inner ring 11 and the inner ring spacer 20 (inner ring spacer piece 21) rotate at a high speed, the small-diameter and large-diameter labyrinths L1 and L2 include the circumference of the outer peripheral surface of the inner ring spacer 20. The air flow in the circumferential direction is generated depending on the speed, but in this case, the higher the peripheral speed, the easier the negative pressure action occurs. Here, between the wall portion 32 and the outer peripheral surface of the pair of inner ring spacer pieces 21, a small-diameter labyrinth L1 that communicates the pair of spacer inner space pieces S2a and S2b is formed. A large-diameter labyrinth L2 that connects the spacer internal space pieces S2a, S2b and the bearing internal space S1 is formed between the inner peripheral surface 30 and the pressure of the large-diameter labyrinth L2 (axially outside) < This is the pressure of the small-diameter labyrinth L1 (axially intermediate side). Therefore, in the spacer inner space pieces S2a and S2b, the air supplied from the external space through the air holes 34 is directed from the small-diameter labyrinth L1 (axially intermediate side) toward the large-diameter labyrinth L2 (axially outer side). It flows (see solid arrow in FIG. 1). And by this air flow, the base oil content of the grease G2 sealed in the inner peripheral surface of the outer ring spacer 30 can be moved to the bearing internal space S1 side through the grease oil passage.

  Here, the base oils of the greases G1 and G2 are held by a thickener corresponding to the fiber structure, and the base oil moves between the fibers of the thickener by capillary action. The grease G1 of the outer ring spacer 30 is in contact with the grease G2 on the inner peripheral surface of the outer ring spacer 30 so that the thickener necessary for the movement of the base oil is also connected. As a result, the base oil of the grease G1 is added to the base oil of the grease G2. Become. As a result, the life of the grease can be extended, and it becomes possible to cope with further high-speed rotation.

  Further, in the pair of spacer inner space pieces S2a and S2b separated by the wall portion 32, the grease G2 is sealed on the inner peripheral surface of the outer ring spacer 30, so that it is sealed in one spacer inner space piece S2a. The grease G2 thus prepared can be used for replenishing one angular ball bearing 10, and the grease G2 enclosed in the other spacer inner space piece S2b can be used for replenishing the other angular ball bearing 10. Thereby, it becomes possible to replenish grease base oil appropriately to each of the pair of angular ball bearings 10, and it is possible to prevent insufficient supply of grease base oil to one angular ball bearing 10.

  Further, since the outer ring spacer 30 is provided with an air hole 34 for supplying air by communicating the small-diameter labyrinth L1 and the outer space of the bearing device 1, the spacer inner space pieces S2a and S2b are provided from the air hole 34. On the other hand, by forcibly sending air intermittently or continuously, it becomes easier to feed the grease base oil into the bearing internal space S1. Furthermore, by controlling the air pressure according to various conditions such as the rotation speed and temperature of the bearing, it is possible to supply proper grease. In addition, what is necessary is just to set optimal conditions according to a bearing structure, arrangement | sequence, use rotation speed, etc. about the number and arrangement | positioning of the air holes 34, intermittent cycle time of supply air, supply amount, supply pressure, etc.

  Further, since the grease G1 in the bearing internal space S1 is about 10 to 20% with respect to the space volume, the running-in time is shortened. For example, when such a bearing device 1 is used as a spindle of a spindle device. The production line return time after spindle replacement can be shortened. Further, when rotating at a high speed like a machine tool spindle, the temperature rise around the angular ball bearing 10 also rises, but the grease G1, G2 also rises and softens accordingly, so that the base oil also flows more easily. There is a tendency. Therefore, it can be said that the bearing device 1 of this embodiment is very suitable for high-speed rotation.

  Further, as in the present embodiment, in the angular ball bearing 10 in which the outer ring 12 has the counter bore 12b, the clearance between the cage 14 and the outer ring 12 is large on the counter bore 12b side, so the inner peripheral surface of the outer ring 12 (counter bore) The grease G1 enclosed in 12b) is easy to collect, and on the other hand, the counter-bore side (plane 12c side) has a small gap between the retainer 14 and the outer ring 12, so that the amount of grease is small. In this case, the base oil lubrication is biased inside the angular ball bearing 10. In particular, in the case of the outer ring guide retainer that guides the retainer 14 on the inner peripheral surface of the outer ring 12, the gap is smaller, so that the bias of the base oil lubrication is increased. However, in the present embodiment, the counter bore 12b is formed on the inner circumferential surface of the outer ring 12 on the outer side in the axial direction than the raceway surface 12a. Therefore, the counter-bore side (plane 12c side) with a small amount of grease accumulation is the outer ring. It will be located in the vicinity of the spacer 30. Accordingly, since the base oil content of the grease G2 sealed in the inner peripheral surface of the outer ring spacer 30 is easily supplied to the counter-counter bore side, the base oil supply balance between the counter-bore 12b side and the counter-counter bore side becomes good. It is possible to increase the lubrication efficiency.

  Further, in the angular ball bearing 10 having a contact angle, a phenomenon (so-called pump action) in which air is sucked toward the counter bore 12b occurs, so that the axial direction outer side (spacer inner space S2 side) to the axial direction outer side ( An air flow is generated toward the bearing inner space S1 (see the solid line arrow in FIG. 1), and the base oil content of the grease G2 on the inner peripheral surface of the outer ring spacer 30 is more smoothly transferred to the bearing inner space S1. It is possible to move to the side.

  In addition, about grease G1, G2, the performance can be improved more by employ | adopting the gel-like grease different from general grease. Gel-like grease has a feature that it easily becomes oily from a gel-like state due to a shearing force generated with rotation, and quickly recovers to a gel-like state when the shearing force disappears, and a low-torque operation can be realized. Therefore, when the greases G1 and G2 are supplied to the rolling surfaces, the change from gel to oil can prevent an instantaneous torque fluctuation due to the engagement of the greases G1 and G2. In addition, by making the grease G1 and G2 in the vicinity of the rolling surface oily, the fluid connection with the grease G1 and G2 slightly away from the rolling surface is improved, and replenishment of base oil from the peripheral portion is promoted. Is done. As the gelling agent to be used, a benzylidene sorbitol derivative or an amino acid gelling agent having a high gelling ability is appropriate. As described above, the efficiency of the base oil lubrication can be increased, and the break-in operation time can be shortened with a low torque. In particular, an effect can be expected in applications having a dmn of 500,000 or more, or a dmn of 1 million or more, such as a machine tool spindle bearing. Note that only one of the grease G1 in the bearing internal space S1 and the grease G2 in the spacer internal space S2 may be gel-like grease. In addition, when applying general grease to grease G1 and G2, it is preferable to set the consistency to 220 to 295, and when applying gel grease, the ratio of gel agent: thickener is set. 50 to 80: 50 to 20 and a consistency of 265 to 275 are preferable.

  Further, the bearing device 1 described above can be used for a spindle device 40 as shown in FIG. 2, for example. The spindle device 40 is a motor built-in spindle device for machine tools, and a rotating shaft 41 is rotatably supported by the housing H via the bearing device 1. A machining tool (not shown) is attached to one end side (left side in FIG. 2) of the rotating shaft 41 in the axial direction. Moreover, the housing H is comprised by the bearing outer ring holder 42, the outer cylinder 43, etc. in an order from the tool side. The outer cylinder 43 is provided with an air supply hole 46 that communicates with the air hole 34 of the bearing device 1 and can supply air.

  Further, the spindle device 40 includes a rotor 44 that is arranged to be rotatable integrally with the rotation shaft 41, and a stator 45 that is arranged around the rotor 44. The outer surface of the stator 45 is fitted and fixed to an outer cylinder 43 that constitutes the housing H. The rotor 44 and the stator 45 constitute a motor M, and by supplying electric power to the stator 45, a rotational force is generated in the rotor 44 to rotate the rotating shaft 41. At this time, the inner ring 11 and the inner ring spacer 20 that are externally fitted to the rotation shaft 41 rotate together with the rotation shaft 41. Then, by supplying air from the air supply hole 46 to the air hole 34, the air flow as described above is generated, and the base oil content of the grease G <b> 2 sealed in the inner peripheral surface of the outer ring spacer 30 is changed to the grease oil path. Since it can be moved to the bearing internal space S1 side via 32a, the life of the grease can be extended, and the spindle device 40 can cope with further high-speed rotation.

  In the case of a motor built-in spindle device such as the spindle device 40, in addition to the heat generated by the angular ball bearing 10, heat generated by the rotor 44 and the stator 45 is also applied, and the enclosed grease G2 is further softened. The replenishability to the bearing inner space S1 side is further improved. In particular, since the angular ball bearing 10 is easily seized during high-speed rotation, more lubrication is required. However, as the rotation speed increases, the replenishability of the grease G2 also improves. It is possible to achieve both prevention of seizure of the bearing 10.

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

  For example, as shown in FIG. 3, the inner peripheral surface of the outer ring spacer 30 in the spacer inner space pieces S2a and S2b and the flange portion 22 of the inner ring spacer piece 21 that radially faces the inner peripheral surface The large-diameter labyrinth L2 is formed into a spacer inner space piece S2a by increasing the diameter from the seat inner space pieces S2a, S2b (axially intermediate side) toward the bearing internal space S1 (axially outer side). , S2b may have a tapered shape with a larger diameter toward the bearing internal space S1.

  In particular, if the axial width of the large-diameter labyrinth L2 is set to be long, a further differential pressure effect in the large-diameter labyrinth L2 leads from the small-diameter side (spacer internal space S2 side) to the large-diameter side (bearing internal space S1 side). Thus, a stronger air flow can be generated.

  The taper angle θ of the large-diameter labyrinth L2 is preferably 5 ° or more and 45 ° or less, and more preferably 10 ° or more and 30 ° or less. If the taper angle θ is smaller than 5 °, the differential pressure effect is reduced, and it is difficult to generate an air flow for the grease G2 to flow into the bearing internal space S1. Further, if the taper angle θ is larger than 45 °, the outer peripheral surface of the flange portion 22 of the inner ring spacer 20 (inner ring spacer piece 21) becomes a sharp edge, and burrs and chips are likely to occur during assembling work or the like. There is a risk that problems such as interference in the large-diameter labyrinth L2 may occur. Moreover, the radial gap of the large-diameter labyrinth L2 is preferably narrower because it is easy to obtain a differential pressure effect. However, in consideration of interference between the outer ring spacer 30 and the inner ring spacer piece 21, parts processing accuracy, and the like. 0.15 mm to 1.0 mm / radius gap is desirable.

  The inner ring spacer 20 is divided into a pair of inner ring spacer pieces 21 in the vicinity of the center in the axial direction of the bearing device 1, and the divided portion overlaps with the pair of large-diameter labyrinths L <b> 2 in the axial direction. As long as it is not, it may be provided at any position.

  In the above-described embodiment, the air hole 34 is provided in the outer ring spacer 30. However, if the small-diameter labyrinth L1 can communicate with the external space of the bearing device 1 to supply air, the inner ring spacer 20 can be supplied. May be provided.

DESCRIPTION OF SYMBOLS 1 Bearing apparatus 10 Angular contact ball bearing 11 Inner ring 11a Raceway surface 12 Outer ring 12a Raceway surface 12b Counter bore 12c Plane 13 Ball 14 Cage 20 Inner ring spacer 21 Inner ring spacer piece 22 Ridge part 30 Outer ring spacer 32 Wall part 34 Air hole 40 Spindle device 41 Rotating shaft 42 Bearing outer ring retainer 43 Outer cylinder 44 Rotor 45 Stator 46 Air supply hole L1 Small diameter labyrinth L2 Large diameter labyrinth S1 Bearing internal space S2 Spacer internal space S2a, S2b Spacer internal space piece G1, G2 Grease θ Taper angle

Claims (5)

An inner ring that is a rotating wheel, an outer ring that is a fixed ring, a plurality of balls disposed between raceways of the inner ring and the outer ring, and a cage that holds the plurality of balls in a freely rolling manner. A pair of angular contact ball bearings arranged coaxially;
An inner ring spacer that is disposed between the pair of inner rings and rotates together with the inner ring;
An outer ring spacer disposed between the pair of outer rings;
A bearing device comprising:
Between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring, a bearing internal space is formed,
Grease is enclosed in the inner peripheral surface of the outer ring in the bearing internal space,
The outer ring spacer is provided with a wall portion projecting radially inward at an axially intermediate portion,
The inner ring spacer is composed of a pair of inner ring spacer pieces that abut in the axial direction,
Each of the pair of inner ring spacer pieces is provided with a flange projecting radially outward at each axial end,
A pair of spacer inner space pieces surrounded by the inner peripheral surface of the outer ring spacer, the wall portion, the outer peripheral surface of the inner ring spacer piece, and the flange are separated by the wall portion. Formed,
Grease is sealed on the inner peripheral surface of each outer ring spacer in the pair of spacer inner space pieces,
Between the wall and the outer peripheral surface of the pair of inner ring spacer pieces, a small-diameter labyrinth that communicates the pair of spacer inner space pieces is formed,
A large-diameter labyrinth that connects the spacer inner space piece and the bearing inner space is formed between the flange and the inner peripheral surface of the outer ring spacer,
The bearing device, wherein the outer ring spacer or the inner ring spacer is provided with an air hole that communicates the small-diameter labyrinth with the external space to supply air. The bearing device according to claim 1, wherein a counterbore is formed on an inner peripheral surface of the outer ring on an outer side in the axial direction than the raceway surface. 3. The bearing device according to claim 1, wherein the large-diameter labyrinth has a tapered shape having a diameter that increases from the spacer internal space piece toward the bearing internal space. The bearing device according to any one of claims 1 to 3, wherein the grease sealed in the inner peripheral surface of the outer ring and / or the inner peripheral surface of the outer ring spacer is a gel-like grease. A rotating shaft to which a processing tool is attached on one end side in the axial direction;
A housing that rotatably supports the rotating shaft via the bearing device according to any one of claims 1 to 4,
A spindle apparatus comprising:

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