Rolling bearing and spindle device for machine tool

Abstract

A rolling bearing is provided with: an inner ring having an inner ring raceway on the outer peripheral surface; an outer ring having an outer ring raceway on the inner peripheral surface; the plurality of rolling bodies are arranged between the inner ring raceway and the outer ring raceway in a free rolling manner; and a cage having a plurality of pockets for holding the plurality of rolling elements, the cage having a pair of circular ring portions arranged side by side in the axial direction and a plurality of column portions arranged at intervals in the circumferential direction so as to connect the pair of circular ring portions to each other. At least one of the pair of circular ring portions has a plurality of protruding protrusions formed on the outer circumferential surface at intervals in the circumferential direction and guided by the inner circumferential surface of the outer ring. The convex protrusions are disposed adjacent to the pockets in the axial direction.

Description

Technical Field

[0001] The invention relates to a rolling bearing and a spindle device for a machine tool. Background Art

[0002] In recent years, rolling bearings used in machine tool spindles and other applications have been required to operate over a wide range of rotational speeds, from low to high speeds, and to rotate stably and quietly in all these ranges. Lubrication is a crucial factor in ensuring stable and quiet rotation of rolling bearings. Supplying an appropriate amount of lubricant to the rolling and sliding parts enables stable and quiet rotation.

[0003] However, in the rolling bearings of the spindle devices for machine tools, the appropriate amount of lubricant varies depending on the rotation range used. Therefore, there is a concern that bearing abnormalities will often occur due to an inappropriate amount. Insufficient lubricant supply will naturally lead to abnormalities, but excessive lubricant supply will also lead to abnormalities. For example, in the high-speed rotation range, abnormal heat may sometimes occur due to the stirring heat of the lubricant, causing bearing damage. In addition, in the low-speed rotation range, the wedge effect formed by the rolling elements and the inner and outer ring raceways may sometimes generate an oil film reaction force, resulting in abnormal vibrations such as self-excited vibrations. In this case, if the amount of lubricant discharged from the rolling bearing is sufficient relative to the amount of lubricant supplied to the rolling and sliding parts, the bearing abnormalities listed above can be suppressed.

[0004] Figures 14 to 16 The figure shows a rolling bearing 100 and its cage 110. This rolling bearing 100 is a typical cylindrical roller bearing with an outer ring guide type cage. The rolling bearing 100 includes an outer ring 102 having an outer ring raceway 102a on its inner circumference; an inner ring 103 having an inner ring raceway 103a on its outer circumference; rolling elements 104 comprising a plurality of cylindrical rollers roamably disposed between the outer ring raceway 102a and the inner ring raceway 103a; and a cage 110 having a plurality of pockets 111 for roamably retaining the plurality of rolling elements 104. This typical outer ring guide type cage 110 includes a pair of annular portions 117 and a plurality of columns 119 arranged at equal intervals in the circumferential direction to connect the pair of annular portions 117. The pockets 111 are formed by the pair of annular portions 117 and two circumferentially adjacent columns 119. In this rolling bearing 100, the outer diameter portions 117a of the pair of annular portions 117 of the retainer 110 serve as guided surfaces and are guided by the outer ring inner diameter portion 102b. However, due to its structure, the guiding gap g between these outer diameter portions 117a and the outer ring inner diameter portion 102b is very small. Consequently, there is a problem in which lubricant discharged from the rolling portion where the rolling elements 104 roll is blocked and retained within the rolling portion.

[0005] Patent Document 1 shows a rolling bearing 200. Figures 17 to 19 As shown, a retainer 210 is provided. The retainer 210 includes a pair of annular portions 217, a plurality of columns 219 connecting the pair of annular portions 217, and pockets 211 for retaining the rolling elements 104. A plurality of convex protrusions 221 are formed on the outer circumferences of the pair of annular portions 217 at positions adjacent to the columns 219 in the axial direction. In a rolling bearing 200 having this structure, lubricant is discharged from between the outer ring inner diameter portion 102b and the annular portion 217 between circumferentially adjacent convex protrusions 221. This facilitates effective lubricant discharge, particularly by utilizing centrifugal force during high-speed rotation and the rotational energy of the rolling elements 104.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 6016632 Summary of the Invention

[0009] Problems that the invention aims to solve

[0010] However, in rolling bearings that continuously supply lubricant using air through a lubrication method such as oil-air lubrication, the lubricant may not be sufficiently drainable in a low-speed rotation range.

[0011] Therefore, an object of the present invention is to provide a rolling bearing and a machine tool spindle device that can improve lubricant discharge performance in all rotational regions and operate smoothly.

[0012] Technical means to solve the problem

[0013] The present invention includes the following configurations.

[0014] (1) A rolling bearing comprising: an inner ring having an inner ring raceway on its outer circumferential surface; an outer ring having an outer ring raceway on its inner circumferential surface; a plurality of rolling elements disposed so as to roll freely between the inner ring raceway and the outer ring raceway; and a retainer having a plurality of pockets for retaining the plurality of rolling elements.

[0015] The retainer includes: a pair of annular portions arranged side by side in the axial direction; and a plurality of column portions arranged at intervals in the circumferential direction so as to connect the pair of annular portions to each other.

[0016] At least one of the pair of annular portions has a plurality of convex protrusions, the plurality of convex protrusions being formed on the outer circumferential surface of the annular portion at intervals in the circumferential direction and being guided by the inner circumferential surface of the outer ring.

[0017] The convex protrusion is arranged adjacent to the pocket in the axial direction.

[0018] (2) A spindle device for a machine tool, comprising the rolling bearing described in (1).

[0019] Effects of the Invention

[0020] According to the present invention, the lubricant discharge performance can be improved in all rotational ranges, thereby enabling smooth operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional view of the rolling bearing according to the first embodiment.

[0022] Figure 2 It is a side view of the rolling bearing according to the first embodiment.

[0023] Figure 3 It is a perspective view of the cage of the rolling bearing according to the first embodiment.

[0024] Figure 4 It is a side view of a part of the rolling bearing according to the first embodiment.

[0025] Figure 5 It is a side view of a part of the rolling bearing according to the first embodiment.

[0026] Figure 6 It is a perspective view illustrating a retainer according to a second embodiment.

[0027] Figure 7 It is a perspective view illustrating a retainer according to a third embodiment.

[0028] Figure 8 It is a perspective view illustrating a retainer according to a fourth embodiment.

[0029] Figure 9 It is a perspective view illustrating a retainer according to a fifth embodiment.

[0030] Figure 10 It is a perspective view illustrating a retainer according to a sixth embodiment.

[0031] Figure 11 Graph showing the frequency spectrum of the vibration acceleration of the rolling bearing of Comparative Example 1.

[0032] Figure 12 Graph showing the frequency spectrum of the vibration acceleration of the rolling bearing of Comparative Example 2.

[0033] Figure 13 This is a graph showing the frequency spectrum of the vibration acceleration of the rolling bearing of Example 1.

[0034] Figure 14This is a cross-sectional view of a general rolling bearing.

[0035] Figure 15 This is a side view of a general rolling bearing.

[0036] Figure 16 This is a perspective view of a typical rolling bearing cage.

[0037] Figure 17 It is a cross-sectional view of a rolling bearing of a conventional structure.

[0038] Figure 18 It is a side view of a rolling bearing of a conventional structure.

[0039] Figure 19 This is a perspective view of a conventional rolling bearing cage.

[0040] Description of Reference Numerals

[0041] 1: Rolling bearings

[0042] 2: Outer ring

[0043] 2a: Outer ring raceway (outer ring raceway surface)

[0044] 3: Inner circle

[0045] 3a: Inner ring raceway (inner ring raceway surface)

[0046] 4: Rolling element

[0047] 10, 20, 30, 40, 50, 60: cage

[0048] 11: Pocket hole

[0049] 12: Ring

[0050] 15: convex protrusion

[0051] 16: Column DETAILED DESCRIPTION

[0052] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0053] (First embodiment)

[0054] Figure 1 It is a cross-sectional view of the rolling bearing 1 according to the first embodiment. Figure 2 It is a side view of the rolling bearing 1 according to the first embodiment. Figure 3 It is a perspective view of the cage 10 of the rolling bearing 1 according to the first embodiment.

[0055] like Figure 1 and Figure 2As shown, the rolling bearing 1 of the first embodiment is a cylindrical roller bearing including a plurality of rolling elements 4 including cylindrical rollers.

[0056] This rolling bearing 1 includes an outer ring 2 having an outer ring raceway surface 2a formed on its inner circumference; an inner ring 3 having an inner ring raceway surface 3a formed on its outer circumference; a plurality of rolling elements 4; and a retainer 10 disposed between the outer ring 2 and the inner ring 3. The retainer 10 has a plurality of pockets 11 formed therein, and the plurality of rolling elements 4 are rotatably retained in each pocket 11.

[0057] like Figure 3 As shown, retainer 10 includes a pair of annular portions 12 arranged side by side in the axial direction, and a plurality of column portions 16 arranged at equal intervals in the circumferential direction to connect the two annular portions 12. In retainer 10, pockets 11 are formed by the pair of annular portions 12 and two circumferentially adjacent column portions 16.

[0058] A plurality of convex protrusions 15 are formed on the outer circumferential surfaces 13 of the pair of annular portions 12 at intervals along the circumferential direction. Each convex protrusion 15 comprises a convex protrusion outer circumferential surface 15a having a larger diameter than the outer circumferential surface of the column portion 16, and a pair of rising portions 15b extending from either side of the convex protrusion outer circumferential surface 15a to the outer circumferential surface 13 of the annular portion 12. The retainer 10 employs an outer ring guide system, which utilizes retainer guide surfaces 2b formed on the inner circumference of the outer ring 2 to guide the convex protrusion outer circumferential surfaces 15a.

[0059] Furthermore, the convex protrusions 15 are arranged axially adjacent to the pockets 11 on the outer circumferential surface 13 of each annular portion 12. In the retainer 10, the multiple convex protrusions 15 of each annular portion 12 are arranged so that every other pocket 11 is axially adjacent to it. Furthermore, the convex protrusions 15 of one annular portion 12 are arranged so that they are axially adjacent to pockets 11 that are not axially adjacent to the convex protrusions 15 of the other annular portion 12. Specifically, the convex protrusions 15 are arranged so that there are no convex protrusions 15 on both axial sides of a pocket 11, and the convex protrusions 15 are arranged on the outer circumferential surfaces 13 of a pair of annular portions 12 in an alternating, staggered arrangement to the left and right of the pockets 11.

[0060] Thus, the rolling bearing 1 of this embodiment includes the retainer 10 having a plurality of convex protrusions 15 formed on the outer peripheral surface 13 of the annular portion 12 at intervals in the circumferential direction. The convex protrusions 15 are formed adjacent to only one axial side of the pocket 11 .

[0061] Therefore, even on one axial side of the pocket 11, the guide gap g1 between the outer peripheral surface 15a of the convex protrusion and the retainer guide surface 2b is smaller than the guide gap g in the general rolling bearing 100 (see FIG. Figure 14 ) Similarly, on the other axial side of pocket 11, or on both sides of column portion 16 where pocket 11 is not present, a relatively large gap G is formed between outer circumferential surface 13 of annular portion 12 and retainer guide surface 2b formed by the inner circumferential surface of outer ring 2. This allows lubricant to be smoothly discharged through this gap G. Furthermore, because the size of guide gap g1 differs from that of gap G, a pressure difference is generated between the two annular portions 12, generating air convection, which further promotes lubricant discharge.

[0062] In particular, the convex protrusions 15 formed as the guide portions are adjacent to the pockets 11 in the axial direction and are alternately arranged in the circumferential direction of the pair of annular portions 12. Therefore, compared with the conventional structure in which the convex protrusions 221 are formed at positions adjacent to the column portions 219 in the axial direction (see Figures 17 to 19 Compared to the conventional rolling bearing 1, the ventilation area between the outer ring 2 and the retainer 10, viewed from the axial direction, is larger. This improves lubricant discharge efficiency not only in the high-speed rotation range but also in the low-speed rotation range, even with an oil-air circulation system that continuously supplies lubricant via air. This improves lubricant discharge efficiency across all rotation ranges, ensuring smooth operation. Consequently, a machine tool spindle device equipped with this rolling bearing 1 can operate stably and quietly.

[0063] Figure 4 and Figure 5 Each is a side view of a portion of the rolling bearing 1 according to the first embodiment.

[0064] like Figure 4 As shown, in the rolling bearing 1 of this embodiment, preferably, in a state where the rotation axis A1 of the cage 10 is aligned with the revolution axis A2 of the rolling element 4, when viewed from the axial direction, the rolling element 4 arranged in the pocket 11 adjacent to the convex protrusion 15 between the outer ring 2 and the cage 10 is not completely hidden by the convex protrusion 15, but is partially exposed (see FIG. Figure 4 (Section E1 in the ).

[0065] In addition, if Figure 5 As shown, in the rolling bearing 1 of the present embodiment, it is preferred that, in a state in which the outer peripheral surface 15a of the convex protrusion 15 of the retainer 10 is in contact with the retainer guide surface 2b of the outer ring 2, when viewed from the axial direction, the rolling elements 4 arranged in the pockets 11 adjacent to the convex protrusion 15 between the outer ring 2 and the retainer 10 are not completely hidden by the convex protrusion 15, but are partially exposed (see FIG. Figure 5 E2 in the .

[0066] In this way, when viewed from the axial direction, between the outer ring 2 and the retaining cage 10, if a portion of the rolling element 4 arranged in the pocket 11 adjacent to the convex protrusion 15 is exposed, then especially when the lubricant is supplied by an oil-gas circulation method, a portion of the air will not be blocked by the convex protrusion 15 but will hit the rolling element 4, so it can be expected that the discharge of the excess lubricant can be further improved.

[0067] Next, an embodiment having a retainer with a different shape will be described. Components identical to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0068] (Second embodiment)

[0069] Figure 6 It is a perspective view illustrating a holder 20 according to a second embodiment.

[0070] like Figure 6 As shown, the retainer 20 used in the second embodiment is configured such that the convex protrusions 15 are formed at positions adjacent to the pockets 11 in the axial direction on only one of the pair of annular portions 12. These convex protrusions 15 are formed on every other pocket 11.

[0071] According to this retainer 20 , particularly in oil-air lubrication, air permeability is improved, and therefore further improvement in lubricant discharge performance can be expected.

[0072] (Third embodiment)

[0073] Figure 7 It is a perspective view illustrating a holder 30 according to a third embodiment.

[0074] like Figure 7 As shown, the retainer 30 used in the third embodiment is similar to the retainer 20 used in the second embodiment, and is also configured such that the convex protrusions 15 are formed on only one of the pair of annular portions 12 at a position axially adjacent to the pockets 11. In this retainer 30, a plurality of convex protrusions 15 are formed at positions axially adjacent to all of the pockets 11.

[0075] Similarly, in the case of the retainer 30 , particularly in the case of oil-air lubrication, the air permeability is improved, and therefore, the lubricant discharge performance can be expected to be further improved.

[0076] Here, in the retainer 20 of the second embodiment in which a convex protrusion 15 is formed in every other pocket 11 in the annular portion 12 on one side, the arrangement interval of the convex protrusion 15 when viewed from the axial direction is increased, and the radial displacement is larger than that of the retainer 10 of the first embodiment.

[0077] In contrast, in the retaining frame 30 of the third embodiment, although convex protrusions 15 are formed on the annular portion 12 on one side, these convex protrusions 15 are formed at positions axially adjacent to all the pockets 11. Therefore, it is expected that the radial displacement of the retaining frame 30 can be maintained equal to that of the retaining frame 10 of the first embodiment, and the air permeability can be improved.

[0078] (Fourth embodiment)

[0079] Figure 8 It is a perspective view illustrating a holder 40 according to a fourth embodiment.

[0080] like Figure 8 As shown, a retainer 40 according to the fourth embodiment is used in an angular contact ball bearing equipped with rolling elements 4 formed of balls. Similar to the retainer 10 used in the first embodiment, this retainer 40 comprises a pair of annular portions 42 arranged side by side in the axial direction, and a plurality of columnar portions 46 arranged at predetermined intervals in the circumferential direction to connect the two annular portions 42. The pair of annular portions 42 and two circumferentially adjacent columnar portions 46 form pockets 41. Pockets 41 are formed in a circular shape, and rolling elements 4 formed of balls are rollably received in these pockets 41.

[0081] Similar to the retainer 10 used in the first embodiment, this retainer 40 also has a plurality of convex protrusions 45 formed on the outer circumferential surfaces 43 of a pair of annular portions 42 at intervals along the circumferential direction. Each convex protrusion 45 comprises a convex protrusion outer circumferential surface 45a having a larger diameter than the outer circumferential surface of the column portion 46, and a pair of rising portions 45b extending from either circumferential side of the convex protrusion outer circumferential surface 45a to the outer circumferential surface 43 of the annular portion 42. The retainer 40 guides the convex protrusion outer circumferential surface 45a using retainer guide surfaces 2b formed on the inner circumferential surface of the outer ring 2.

[0082] Furthermore, the convex protrusions 45 are also arranged axially adjacent to the pockets 41 on the outer circumferential surface 43 of each annular portion 42. The multiple convex protrusions 45 on each annular portion 42 are arranged axially adjacent to every other pocket 41. Specifically, the convex protrusions 45 are arranged so that there are no convex protrusions 45 on both axial sides of the pocket 41. Instead, the convex protrusions 45 are arranged on the outer circumferential surfaces 43 of a pair of annular portions 42 in an alternating, staggered arrangement, with respect to the left and right pockets 41. This arrangement allows lubricant to be smoothly discharged from the angular contact ball bearing, thereby improving lubricant discharge and ensuring smooth operation throughout the entire rotational range.

[0083] (Fifth embodiment)

[0084] Figure 9 It is a perspective view illustrating a holder 50 according to a fifth embodiment.

[0085] like Figure 9 As shown, the retainer 50 used in the fifth embodiment is similar to the retainer 40 of the fourth embodiment and is also used in an angular contact ball bearing having rolling elements 4 formed of balls. In this retainer 50, convex protrusions 45 are formed only on one of the pair of annular portions 42, at a position adjacent to the pockets 41 in the axial direction. These convex protrusions 45 are formed on every other pocket 41.

[0086] According to this retainer 40 , similarly to the retainer 20 of the second embodiment, particularly during oil-air lubrication, air permeability is improved, and therefore further improvement in lubricant discharge performance can be expected.

[0087] (Sixth embodiment)

[0088] Figure 10 It is a perspective view illustrating a holder 60 according to a sixth embodiment.

[0089] like Figure 10 As shown, in the retainer 60 used in the sixth embodiment, similar to the retainer 50 used in the fifth embodiment, the convex protrusions 45 are formed only on one of the pair of annular portions 42 at a position axially adjacent to the pockets 41. In this retainer 60, a plurality of convex protrusions 45 are formed at positions axially adjacent to all the pockets 41.

[0090] Similarly, in the case of the retainer 60 , particularly in the case of oil-air lubrication, the air permeability is improved, and therefore, the lubricant discharge performance can be expected to be further improved.

[0091] In addition, the retainer 60 also has convex protrusions 45 formed on the annular portion 42 on one side, similar to the retainer 30 of the third embodiment, but these convex protrusions 45 are formed at positions adjacent to all the pockets 41 in the axial direction. Therefore, it is expected that the radial displacement of the retainer 60 can be maintained at the same level as that of the retainer 10 of the first embodiment, while at the same time improving the air permeability.

[0092] The present invention is not limited to the above-mentioned embodiments, and can be appropriately modified and improved. In the above-mentioned embodiments, cylindrical roller bearings and angular contact ball bearings are described, but the present invention can also be applied to other rolling bearings such as deep groove ball bearings and tapered roller bearings. In addition, when considering use under high-speed rotation, the retaining material is preferably a synthetic resin that is lighter than metal and has excellent wear resistance, which can be phenol, polyamide, PPS (Polyphenylene sulfide), PEEK (polyetherether ketone), polyimide, etc. In addition, reinforcing agents such as glass fiber, carbon fiber, and aromatic polyamide fiber can also be added to these materials.

[0093] Example

[0094] The rolling bearing supporting the rotating shaft is assembled on the outer cylinder, and the rotating shaft is rotated while supplying lubricant to the rolling bearing in an oil-air circulation manner. The spectrum of the vibration acceleration at the outer cylinder is measured. Figure 14 The rolling bearing 100 (Comparative Example 1) shown Figure 17 The rolling bearing 200 (Comparative Example 2) shown in FIG. Figure 1 The rolling bearing 1 (Example 1) shown in the figure was used. The dimensions of each rolling bearing were set to 90 mm in outer diameter, 55 mm in inner diameter, and 18 mm in width.

[0095] Figures 11 to 13 The results show that in Comparative Examples 1 and 2 and Example 1, the rotation speed is relatively low at 2000 min. -1 The frequency spectrum of the vibration acceleration measured on the outer cylinder during downward rotation.

[0096] like Figure 11 As shown in FIG. 1 , a peak P1 considered to be an abnormal vibration can be confirmed in Comparative Example 1. Figure 12 As shown in FIG, in Comparative Example 2, similarly to Comparative Example 1, a peak P2 considered to be an abnormal vibration can also be confirmed. Figure 13 As shown, in Example 1, no peak considered to be abnormal vibration was observed, and a stable state was confirmed.

[0097] The results show that in Example 1, the occurrence of abnormal vibration is suppressed. In particular, the occurrence of abnormal vibration at low speeds in oil-air lubrication, which was listed as a problem in Comparative Example 2, is suppressed by the present invention.

[0098] In this way, the present invention is not limited to the above-mentioned embodiments. The intended content of the present invention also includes combining the various components of the embodiments with each other, or changing and applying them based on the description in the specification and known technologies by those skilled in the art, and such content is included in the scope of protection required.

[0099] As described above, this specification discloses the following matters.

[0100] (1) A rolling bearing comprising: an inner ring having an inner ring raceway on its outer circumferential surface; an outer ring having an outer ring raceway on its inner circumferential surface; a plurality of rolling elements disposed so as to roll freely between the inner ring raceway and the outer ring raceway; and a retainer having a plurality of pockets for retaining the plurality of rolling elements.

[0101] The retainer includes: a pair of annular portions arranged side by side in the axial direction; and a plurality of column portions arranged at intervals in the circumferential direction so as to connect the pair of annular portions to each other.

[0102] At least one of the pair of annular portions has a plurality of convex protrusions formed on the outer peripheral surface at intervals in the circumferential direction and guided by the inner peripheral surface of the outer ring.

[0103] The convex protrusion is arranged adjacent to the pocket in the axial direction.

[0104] With this rolling bearing, even if the guide clearance between the convex protrusion and the inner circumferential surface of the outer ring is narrow on one axial side of the pocket, a larger clearance is formed between the outer circumferential surface of the annular portion and the inner circumferential surface of the outer ring on the other axial side of the pocket, or on both sides of the column portion where no pocket exists. This allows lubricant to be discharged smoothly from this clearance. Furthermore, the pressure difference between the two annular portions generates air convection, which further promotes lubricant discharge.

[0105] In particular, the convex protrusions forming the guides are positioned axially adjacent to the pockets. This increases the ventilation area between the outer ring and the retainer when viewed axially, compared to a case where the protrusions are positioned axially adjacent to the columns. This improves lubricant discharge efficiency not only in the high-speed rotation range but also in the low-speed rotation range, even with an oil-air circulation system that continuously supplies lubricant via air. In other words, lubricant discharge efficiency is improved across all rotation ranges, ensuring smooth operation.

[0106] (2) In the rolling bearing according to (1), a portion of the rolling element arranged in the pocket adjacent to the convex protrusion in the axial direction is exposed from the convex protrusion when viewed in the axial direction.

[0107] According to this rolling bearing, when lubricant is supplied by the oil-air circulation system, part of the air is not blocked by the convex protrusions but hits the rolling elements, thereby further improving the discharge performance of excess lubricant.

[0108] (3) The rolling bearing according to (1) or (2), further comprising cylindrical rollers as the rolling elements.

[0109] According to this rolling bearing, in a cylindrical roller bearing including cylindrical rollers, the lubricant discharge performance in all rotational regions can be improved, thereby achieving stable and quiet rotation.

[0110] (4) The rolling bearing according to (1) or (2), further comprising balls as the rolling elements.

[0111] According to this rolling bearing, in an angular contact ball bearing including balls, the discharge performance of the lubricant in all rotational regions can be improved, thereby achieving stable and quiet rotation.

[0112] (5) A main spindle device for a machine tool, comprising the rolling bearing according to any one of (1) to (4).

[0113] According to this machine tool spindle device, stable and quiet operation is possible.

[0114] It should be noted that this application is based on the Japanese patent application (Japanese Patent Application No. 2023-017847) filed on February 8, 2023, the contents of which are incorporated herein by reference.

Claims

1. A rolling bearing, characterized in that: The invention comprises an inner ring having an inner ring raceway on its outer circumferential surface; an outer ring having an outer ring raceway on its inner circumferential surface; a plurality of rolling elements, the plurality of rolling elements being arranged to roll freely between the inner ring raceway and the outer ring raceway; and a retainer having a plurality of pockets for retaining the plurality of rolling elements. The retainer includes: a pair of annular portions arranged side by side in the axial direction; and a plurality of column portions arranged at intervals in the circumferential direction so as to connect the pair of annular portions to each other. At least one of the pair of annular portions has a plurality of convex protrusions, the plurality of convex protrusions being formed on the outer circumferential surface of the annular portion at intervals in the circumferential direction and being guided by the inner circumferential surface of the outer ring. The convex protrusion is arranged adjacent to the pocket in the axial direction.

2. The rolling bearing according to claim 1, wherein When viewed in the axial direction, a portion of the rolling element arranged in the pocket adjacent to the convex protrusion in the axial direction is exposed from the convex protrusion.

3. The rolling bearing according to claim 1 or 2, characterized in that Cylindrical rollers are provided as the rolling elements.

4. The rolling bearing according to claim 1 or 2, characterized in that Balls are provided as the rolling elements.

5. A spindle device for a machine tool, characterized in that: A rolling bearing according to claim 1 or 2.

6. A spindle device for a machine tool, characterized in that: A rolling bearing according to claim 3 is provided.

7. A spindle device for a machine tool, characterized in that: A rolling bearing according to claim 4 is provided.

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