JPWO2012023437A1 - Rolling bearings and spindles for machine tools - Google Patents

Abstract

The present invention relates to a rolling bearing and a machine tool capable of suppressing the abnormal temperature rise of the rolling bearing and improving the time required for the break-in operation when performing grease lubrication by improving the discharging performance of the lubricant. A spindle device is provided. The cage 10 used in the rolling bearing according to the present invention includes a pair of annular portions 12 arranged side by side in the axial direction, and a plurality of cages 10 arranged at predetermined intervals in the circumferential direction so as to connect the pair of annular portions 12. Column part 16. Each annular portion 12 has a plurality of convex protrusions 15 formed on the outer peripheral surface 13 so as to be spaced apart in the circumferential direction. The convex projection 15 of one annular portion 12 is formed at a position different from the convex projection 15 of the other annular portion 12 in the circumferential direction.

Description

  The present invention relates to a rolling bearing and a spindle device for a machine tool, and more particularly to a rolling bearing used for a spindle of a machine tool that rotates at high speed, a high-speed motor, and the like, and a spindle device for a machine tool using the rolling bearing.

  Bearings used in spindle devices for machine tools in recent years have been increased in speed for high-efficiency machining. If the lubricant discharging performance is poor in a bearing rotating at a high speed, the lubricant becomes excessive, and abnormal heat generation occurs due to stirring heat. In such a case, the bearing temperature may rise abnormally and the bearing may be damaged.

  FIG. 10 shows a cylindrical roller bearing 100 conventionally used. The cylindrical roller bearing 100 includes a plurality of outer rings 102 having an outer ring raceway 102a on the inner peripheral surface, an inner ring 103 having an inner ring raceway 103a on the outer peripheral surface, and a plurality of rolls provided between the outer ring raceway 102a and the inner ring raceway 103a. And a cage 110 having a plurality of pockets 111 for holding the plurality of rollers 104. Here, the retainer 110 is an outer ring guide system, and the outer peripheral surface 110a of the retainer 110 functions as a guided surface.

  In such an outer ring guide type retainer 110, since the guide gap g ′ between the outer peripheral surface 110a of the retainer 110 and the inner peripheral surface of the outer ring 102 is narrow, the lubricant dischargeability is poor, and the cylindrical roller bearing There is a tendency that an abnormal temperature rise of 100 tends to occur. Furthermore, in such a cylindrical roller bearing 100, since the outer ring raceway 102a and the inner ring raceway 103a and the roller (rolling element) 104 are in line contact, the outer ring raceway 102a and the inner ring raceway 103a, and the ball (rolling element) and The cylindrical roller bearing 100 is more likely to be heated than a ball bearing that makes point contact.

  When grease lubrication is performed, after the grease is sealed in the bearing, so-called break-in operation is performed in order to disperse the sealed grease evenly in the bearing or to move the excess grease to the periphery of the bearing. It is essential. In such an outer ring guide type retainer 110, since the guide gap g ′ between the outer peripheral surface 110a of the retainer 110 and the inner peripheral surface of the outer ring 102 is narrow, the discharge of the lubricant is poor and the running-in time is long. There is such a tendency.

  In order to improve the discharging property of the lubricant, it has been conventionally proposed to provide a recessed portion on the guided surface of the cage (see, for example, Patent Document 1 and Patent Document 2).

Japanese Patent No. 3655151 Japanese Patent No. 4342612

  According to the rolling bearings described in Patent Documents 1 and 2, the lubricant dischargeability can be improved by the recess provided in the guided surface of the cage. However, when the lubricant is excessive, there has been a problem that abnormal temperature rise of the rolling bearing is likely to occur.

  The present invention has been made in view of the above circumstances, and an object thereof is to improve the discharge performance of the lubricant, thereby suppressing the abnormal temperature rise of the rolling bearing and necessary for the running-in operation when performing grease lubrication. It is an object of the present invention to provide a rolling bearing and a machine tool spindle device that can shorten the time required.

The above object of the present invention can be achieved by the following constitution.
(1) An inner ring having an inner ring raceway on an outer peripheral surface, an outer ring having an outer ring raceway on an inner peripheral surface, a plurality of rolling elements provided in a freely rollable manner between the inner ring raceway and the outer ring raceway, A rolling bearing comprising a plurality of pockets for holding the rolling elements of:
The retainer has a predetermined interval in the circumferential direction so as to connect the first and second annular portions arranged side by side in the axial direction, and the first and second annular portions. A plurality of pillars arranged in,
The first annular part and the second annular part have a plurality of convex protrusions formed on the outer peripheral surfaces so as to be spaced apart in the circumferential direction,
The rolling bearing, wherein the convex protrusion of the second annular part is formed at a position different from the convex protrusion of the first annular part in the circumferential direction.
(2) The rolling bearing according to (1), wherein the convex protrusions of the first annular part and the convex protrusions of the second annular part are formed at equal intervals in the circumferential direction.
(3) The convex projections of the first annular part and the convex projections of the second annular part are respectively formed adjacent to the column part in the axial direction (1) or (2) The rolling bearing described.
(4) A spindle device for a machine tool in which the rolling bearing according to any one of (1) to (3) is used.

  According to the rolling bearing and the machine tool spindle device of the present invention, the lubricant can be smoothly discharged from the portion of the cage where the convex protrusion is not provided. Thereby, the abnormal temperature rise of the rolling bearing can be suppressed, and the running-in time can be shortened when grease lubrication is performed.

It is sectional drawing of the rolling bearing which concerns on 1st Embodiment of this invention. It is a perspective view of the holder | retainer of FIG. 2 shows the cage of FIG. 2, (a) is a front view, and (b) is a partial top view seen from the I direction of (a). FIG. The cage | basket of the rolling bearing which concerns on 2nd Embodiment of this invention is shown, (a) is a front view, (b) is the partial top view seen from the II direction of (a). The cage of the rolling bearing which concerns on 3rd Embodiment of this invention is shown, (a) is a front view, (b) is the partial top view seen from the III direction of (a). It is sectional drawing which shows the testing apparatus used in Example 1,2. 3 is a graph showing test results of Example 1. The holder | retainer used for the rolling bearing of the comparative example 2 is shown, (a) is a front view, (b) is the partial top view seen from the X direction of (a). 6 is a graph showing the test results of Example 2. It is sectional drawing of the conventional rolling bearing.

  Hereinafter, each embodiment of the rolling bearing according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
A rolling bearing according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a sectional view of a cylindrical roller bearing 1 according to the first embodiment. FIG. 2 shows a perspective view of the cage 10 of FIG. FIG. 3 shows the cage 10 of FIG. 2, (a) is a front view of the cage 10, and (b) is a partial top view seen from the I direction of (a).

  As shown in FIG. 1, a cylindrical roller bearing 1 includes an outer ring 2 having an outer ring raceway surface 2a formed on an inner peripheral surface, an inner ring 3 having an inner ring raceway surface 3a formed on an outer peripheral surface, and a plurality of rolling elements. The cylindrical roller 4 and the cage 10 disposed between the outer ring 2 and the inner ring 3 are provided. A plurality of pockets 11 are formed in the cage 10, and a plurality of cylindrical rollers 4 are rotatably held in each pocket 11.

  As shown in FIG. 2, the cage 10 is arranged at a predetermined interval in the circumferential direction so as to connect the pair of annular portions 12 arranged side by side in the axial direction and the two annular portions 12. A plurality of column portions 16. A pocket 11 is formed by the pair of annular portions 12 and the two column portions 16 adjacent in the circumferential direction. Further, on both circumferential sides of the intermediate portion in the axial direction of the column portion 16, roller stopper portions 14 for reliably holding the cylindrical rollers 4 are provided so as to protrude from the outer peripheral surface of the column portion 16.

  A plurality of convex protrusions 15 are formed on the outer peripheral surface 13 of the pair of annular portions 12 at predetermined intervals in the circumferential direction. Each convex protrusion 15 includes a convex protrusion outer peripheral surface 15a having a larger diameter than the outer peripheral surface of the column part 16, and an outer peripheral surface of the annular part 12 from both sides in the circumferential direction of the convex protrusion outer peripheral surface 15a. 13 and a pair of rising portions 15b. The cage 10 is an outer ring guide system in which the convex protrusion outer peripheral surface 15 a is guided by a cage guide surface formed on the inner peripheral surface of the outer ring 2.

  Further, the convex protrusion 15 is disposed on the outer peripheral surface 13 of each annular portion 12 so as to be adjacent to the column portion 16 in the axial direction. Here, as shown in FIG. 2, FIG. 3A and FIG. 3B, in the cage 10 used in the first embodiment, the plurality of convex protrusions 15 of each annular portion 12 is one. It arrange | positions so that every other pillar part 16 may adjoin to an axial direction. Further, the convex protrusion 15 of the one annular portion 12 is arranged so that the convex protrusion 15 of the other annular portion 12 is adjacent in the axial direction to the column 16 that is not adjacent in the axial direction. Has been. That is, the convex protrusions 15 are arranged so that the convex protrusions 15 do not exist on both sides in the axial direction of the column part 16, so that the column parts 16 are alternately arranged on the left and right sides in a staggered manner. These are disposed on the outer peripheral surfaces of the pair of annular portions 12.

  As described above, the cylindrical roller bearing 1 according to the first embodiment includes the cage 10 in which a plurality of convex protrusions 15 are formed on the outer peripheral surface 13 at predetermined intervals in the circumferential direction. The protruding portion 15 is formed so as to be adjacent to only one side of the column portion 16 in the axial direction. Therefore, on one side in the axial direction of the column part 16, even if the guide gap g between the convex protrusion outer peripheral surface 15a and the cage guide surface is the same as the conventional guide gap g ′, the axis of the column part 16 The gap G between the outer peripheral surface 13 of the annular portion 12 and the inner peripheral surface (cage guide surface) of the outer ring 2 is large at the other side in the direction and at the portion where the column portion 16 does not exist. Therefore, the lubricant can be discharged smoothly from the gap G. Further, since the size of the guide gap g and the size of the gap G are different, a pressure difference is generated between the two annular portions 12 to cause air convection, and the lubricant discharge is further promoted by the convection action. Moreover, since the air resistance at the time of high speed rotation is eased by having the rising part 15b which continues from the circumferential direction both sides of the convex-projection part outer peripheral surface 15a to the outer peripheral surface 13 of the annular part 12, respectively, it is lubricant. Emissions are further improved. Therefore, according to the cylindrical roller bearing 1 according to the present embodiment, abnormal temperature rise during high-speed rotation can be suppressed, and the time for running-in can be shortened even when grease lubrication is performed.

(Second Embodiment)
Next, the rolling bearing which concerns on 2nd Embodiment of this invention is demonstrated based on FIG. 4A and 4B show the cage 20 used in the cylindrical roller bearing according to the second embodiment, in which FIG. 4A is a front view of the cage 20 and FIG. .

  Similar to the cage 10 used in the first embodiment, the cage 20 used in the second embodiment connects the pair of annular portions 22 arranged in the axial direction and the two annular portions 22. As described above, the plurality of column portions 26 are arranged at predetermined intervals in the circumferential direction. A pocket 21 is formed by the pair of annular portions 22 and the two column portions 26 adjacent in the circumferential direction. Further, roller stoppers 24 are provided on both sides in the circumferential direction of the axial direction intermediate portion of the column portion 26 so as to protrude from the outer peripheral surface of the column portion 26.

  A plurality of convex protrusions 25 are formed on the outer peripheral surface 23 of the pair of annular portions 22 at predetermined intervals in the circumferential direction. Each convex protrusion 25 includes a convex protrusion outer peripheral surface 25a having a larger diameter than the outer peripheral surface of the column 26, and an outer peripheral surface of the annular portion 22 from both sides in the circumferential direction of the convex protrusion outer peripheral surface 25a. 23, and a pair of rising portions 25b continuing to 23. The cage 20 is an outer ring guide system in which the convex protrusion outer peripheral surface 25a is guided by a cage guide surface formed on the inner peripheral surface of the outer ring.

  Also in the cage 20 used in the second embodiment, the convex protrusions 25 are arranged so that the convex protrusions 25 do not exist on both sides of the column part 26 in the axial direction. Further, in the cage 20, unlike the first embodiment, the plurality of convex protrusions 15 of each annular portion 12 are arranged so as to be adjacent to every other column portion 16 in the axial direction. Yes. With such an arrangement, the lubricant can be discharged more smoothly from the cylindrical roller bearing, so that an abnormal temperature rise during high-speed rotation can be suppressed, and a break-in operation time can be shortened even when grease lubrication is performed. it can.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. 5A and 5B show a cage 30 used in the angular ball bearing according to the third embodiment. FIG. 5A is a front view of the cage 30 and FIG. .

  Like the cage 10 used in the first embodiment, the cage 30 shown in FIG. 5 connects a pair of annular portions 32 arranged side by side in the axial direction and the annular portions 32, And a plurality of column portions 36 arranged at predetermined intervals in the circumferential direction. A pocket 31 is formed by the pair of annular portions 32 and the two column portions 36 adjacent to each other in the circumferential direction.

  The outer peripheral surface 33 of the pair of annular portions 32 has a plurality of convex portions having a convex protrusion outer peripheral surface 35a having a larger diameter than the outer peripheral surface of the column portion 36 and a pair of convex protrusion peripheral side surfaces 35b. The protruding portions 35 are formed at predetermined intervals in the circumferential direction. The pair of convex protrusion circumferential side surfaces 35b connect the outer peripheral surface 33 of the annular portion 32 and the convex protrusion outer peripheral surface 35a at substantially right angles on both sides in the circumferential direction of the convex protrusion outer peripheral surface 35a. Yes. The cage 30 is an outer ring guide system in which the convex protrusion outer peripheral surface 35a is guided by a cage guide surface formed on the inner peripheral surface of the outer ring. During the rotation of the angular ball bearing, the convex protrusion outer peripheral surface 35 a is lubricated by the lubricant accumulated at the intersection of the convex protrusion circumferential side surface 35 b and the outer peripheral surface 33 of the annular portion 32.

  Also in the cage 30 used in the third embodiment, the convex protrusions 35 are arranged so that the convex protrusions 35 do not exist on both axial sides of the column part 36. Similarly to the cage 10 used in the first embodiment, a plurality of convex protrusions 35 of each annular portion 32 are arranged so as to be adjacent to every other column portion 36 in the axial direction. ing. With such an arrangement, the lubricant can be smoothly discharged from the angular ball bearing, so that abnormal temperature rise during high-speed rotation can be suppressed, and the time for running-in can be shortened even when grease lubrication is performed. .

  Note that the present invention is not limited to the above-described embodiment, and can be changed or improved as appropriate. In the above embodiment, the cylindrical roller bearing and the angular ball bearing have been described. However, the present invention can also be applied to other rolling bearings such as a deep groove ball bearing and a tapered roller bearing. In consideration of use at high speed, the cage material is preferably a synthetic resin that is lighter than metal and excellent in wear resistance, such as phenol, polyamide, PPS, PEEK, and polyimide. Further, reinforcing agents such as glass fiber, carbon fiber, and aramid fiber may be added to them.

  Further, the convex protrusion is not limited to the arrangement adjacent to the pillar in the axial direction, and may be arranged anywhere on the outer peripheral surface of the annular portion. For example, the convex protrusion may be arranged so as to be adjacent to the pocket in the axial direction. Even when the convex protrusion is adjacent to one side of the pocket in the axial direction, the guide gap g on the one side of the pocket in the axial direction is not limited as long as the convex protrusion is not disposed on the other side of the pocket in the axial direction. The size of the gap G is different from that of the gap G on the other side in the axial direction, and a pressure difference occurs between the annular portions, and air convection occurs. Thereby, the discharge of the lubricant is promoted by the convection action. It should be noted that whether the rising portions are provided on both sides in the circumferential direction of the convex protrusions or whether the side surfaces of the convex protrusions are provided in the circumferential direction can be appropriately determined according to the purpose of use of the rolling bearing.

  Here, a test was conducted on the relationship between the temperature rise during the high-speed rotation of the rolling bearing and the shape of the cage. FIG. 6 is a cross-sectional view of an evaluation test apparatus 50 used in this test. The cylindrical roller bearing 1 as a test bearing is incorporated in the housing 51 so as to support one end side of the rotary shaft 52. . The lubricant is supplied to the cylindrical roller bearing 1 through the nozzle 53. The test was performed using the cylindrical roller bearing 1 (invention example) shown in FIG. 1 and the cylindrical roller bearing 100 (comparative example 1) shown in FIG. The test conditions of Example 1 (Test Condition 1) are shown below.

(Test condition 1)
・ Bearings: Cylindrical roller bearings (N1011RSTPKR)
・ Size: inner diameter Φ55mm x outer diameter Φ90mm x width 18mm
・ Oil quantity condition: 0.01cc / 1shot (intermittent oil supply every 2 minutes)
・ Used oil: Turbine oil VG32

  FIG. 7 shows the test results of Example 1. From FIG. 7, the cylindrical roller bearing 100 of Comparative Example 1 rapidly increases in temperature as time elapses from the start of operation and the rotation speed increases, whereas the cylindrical roller bearing 10 of the invention example increases in temperature. It turns out that it is suppressed. From this test result, it can be seen that in the cylindrical roller bearing 1 of the present invention example, the dischargeability of the lubricant is improved and the abnormal temperature rise can be suppressed.

  About the relationship between the temperature rise at the time of high-speed rotation of a rolling bearing and the shape of a cage, the test conditions were changed from Example 1 and the test was performed. In the test of the second embodiment, the evaluation test apparatus 50 shown in FIG. 6 is used as in the first embodiment. The test is a rolling roller bearing (comparative example 2) in which the cylindrical roller bearing 1 shown in FIG. 1 (invention example), the cylindrical roller bearing 100 shown in FIG. 10 (comparative example 1), and the cage 210 shown in FIG. 8 are used. It was performed using. The test conditions for this test (Test Condition 2) are shown below.

(Test condition 2)
・ Bearings: Cylindrical roller bearings (N1011RSTPKR)
・ Size: inner diameter Φ55mm x outer diameter Φ90mm x width 18mm
・ Oil quantity condition: 0.01cc / 1shot (intermittent oil supply every 8 minutes)
・ Used oil: Turbine oil VG32

  The retainer 210 shown in FIG. 8 is similar to the retainer 10 used in the first embodiment of the present invention, between a pair of annular portions 212 arranged in the axial direction and between the annular portions 212. A plurality of pillars 216 arranged at predetermined intervals in the circumferential direction so as to be connected. A pocket 211 is formed by the pair of annular portions 212 and the two column portions 216 adjacent in the circumferential direction. A plurality of convex protrusions 215 are formed on the outer peripheral surfaces 213 of the pair of annular portions 212 so as to sandwich the column portion 216 from both sides in the axial direction. Each convex protrusion 215 has a convex protrusion outer peripheral surface 215 a having a larger diameter than the outer peripheral surface of the column part 216. The cage 210 is an outer ring guide system in which the convex protrusion outer peripheral surface 215a is guided by a cage guide surface formed on the inner peripheral surface of the outer ring.

  FIG. 9 shows the test results of Example 2. FIG. 9 shows that the temperature rise of the cylindrical roller bearing 1 of the invention example is suppressed as compared with the cylindrical roller bearings of Comparative Examples 1 and 2. From this test result, it can be seen that in the cylindrical roller bearing 1 of the present invention example, the lubricant dischargeability is improved and the temperature rise is suppressed.

  Here, in the cylindrical roller bearing 1 of the invention example, the temperature rise is suppressed more than the cylindrical roller bearing of the comparative example 2. In the cage 210 used in the comparative example 2, the convex protrusion 215 is a column part. 216 is arranged on both sides in the axial direction, whereas in the cage 10 used in the invention example, the convex protrusion 15 is formed only on one side in the axial direction of the column part 16. It is believed that there is. The column part 216 of the cage 210 used in Comparative Example 2 has an outer ring (not shown) in the outer diameter direction, cylindrical rollers (not shown) on both sides in the circumferential direction, and convex protrusions 215 on both sides in the axial direction. A closed space is formed. Since air convection hardly occurs in the closed space, the lubricant that has entered the closed space is difficult to be discharged from the closed space to the outside.

  On the other hand, in the cylindrical roller bearing 1 of the invention example, the lubricant adhering to the outer peripheral side of the column part 16 is smoothly applied from one side of the column part 16 in the axial direction (the side where the convex protrusion 15 is not formed). Can be discharged. Further, since the size of the guide gap g and the gap G formed between the cage 10 and the outer ring 2 is different on both sides in the axial direction of the column part 16, a pressure difference is generated between both annular parts 12. Air convection occurs. Thereby, since discharge | emission of a lubricant is further accelerated | stimulated by a convection effect | action, the discharge property of a lubricant is improving. Therefore, according to the cylindrical roller bearing 1 according to the invention example, an abnormal temperature rise during high-speed rotation can be suppressed, and the running-in time can be shortened even when grease lubrication is performed.

  The embodiments and examples of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. Is. This application is based on a Japanese patent application filed on August 18, 2010 (Japanese Patent Application No. 2010-183349), the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 Cylindrical roller bearing 2 Outer ring 2a Outer ring raceway surface 3 Inner ring 3a Inner ring raceway surface 4 Cylindrical roller 10 Cage 11 Pocket 12 Ring part 15 Convex protrusion part 16 Column part

Claims (4)

An inner ring having an inner ring raceway on an outer peripheral surface, an outer ring having an outer ring raceway on an inner peripheral surface, a plurality of rolling elements provided to roll between the inner ring raceway and the outer ring raceway, and the plurality of rolling elements A cage having a plurality of pockets for holding a rolling bearing,
The retainer has a predetermined interval in the circumferential direction so as to connect the first and second annular portions arranged side by side in the axial direction, and the first and second annular portions. A plurality of pillars arranged in,
The first annular part and the second annular part have a plurality of convex protrusions formed on the outer peripheral surfaces so as to be spaced apart in the circumferential direction,
The rolling bearing, wherein the convex protrusion of the second annular part is formed at a position different from the convex protrusion of the first annular part in the circumferential direction.   The rolling bearing according to claim 1, wherein the convex protrusions of the first annular part and the convex protrusions of the second annular part are formed at equal intervals in the circumferential direction.   3. The rolling bearing according to claim 1, wherein the convex protrusions of the first annular part and the convex protrusions of the second annular part are respectively formed adjacent to the column part in the axial direction.   A spindle device for a machine tool in which the rolling bearing according to any one of claims 1 to 3 is used.

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