WO2013002252A1

WO2013002252A1 - Rolling bearing

Info

Publication number: WO2013002252A1
Application number: PCT/JP2012/066366
Authority: WO
Inventors: 小杉太
Original assignee: Ntn株式会社
Priority date: 2011-06-30
Filing date: 2012-06-27
Publication date: 2013-01-03
Also published as: CN103635708B; DE112012002734T5; CN105605101B; JP2013015152A; CN105605101A; KR101968714B1; DE112012002734B4; JP5917030B2; KR20140033427A; CN103635708A

Abstract

In a rolling bearing used for supporting the principal axis of machine tools and the like, oil supply holes (5) for air-oil lubrication that penetrate through to the bearing space are provided in the outer ring (2). On both side surfaces of the outer ring (2), notches (9) for exhausting the air-oil that are indented in the axial direction of the bearing are provided from the internal diameter surface (2b) to the external diameter surface (2c). In addition to providing a circumferential groove (6) that communicates with the oil supply holes (5) on the external diameter surface of the outer ring (2), ring-shaped grooves (7, 7) are severally provided on both sides of the circumferential groove (6) on said external diameter surface of the outer ring (2) and in each ring-shaped groove (7), a ring-shaped sealing member (8) is provided.

Description

Rolling bearing

Related applications

This application claims the priority of Japanese Patent Application No. 2011-146142 filed on June 30, 2011, which is incorporated herein by reference in its entirety.

This invention relates to a rolling bearing used for supporting, for example, a machine tool spindle.

FIG. 16 is a longitudinal sectional view of a conventional rolling bearing with a nozzle spacer. In this rolling bearing,

exhaust notches

71 and 71 are provided in the spacer 70, and the lubricant used for lubricating the bearing is discharged from the

exhaust notches

71 and 71 to the outside of the bearing. In a rolling bearing, there is a system in which an oil supply hole that communicates from an outer diameter portion to an inner diameter portion is provided in an outer ring, and oil is supplied from the oil supply hole (Patent Document 1). In this method, when the bearings are used in combination with the back surface, it is necessary to provide a spacer between the bearings in which an exhaust port (notch) for exhausting air oil is formed.

Japanese Utility Model Publication No. 63-180726

When a bearing having an oil supply hole 73 in the outer ring 72 shown in FIG. 17 is used without a spacer in the rear combination as shown in FIG. 18, there is no exhaust port for discharging air oil between the bearings. There is a possibility that the lubricating oil stays or gets inside the bearing, resulting in temperature instability or, in the worst case, excessive temperature rise.

An object of the present invention is to provide a rolling bearing capable of smoothly discharging the air oil supplied into the bearing space to the outside of the bearing when a bearing having an oil supply hole in the outer ring is used without a spacer. That is.

A rolling bearing according to the present invention is a rolling bearing in which rolling elements are interposed between rolling surfaces of an inner ring and an outer ring, and the outer ring is provided with an oil supply hole for air oil lubrication penetrating into a bearing space. One or both of the width surfaces are provided with notch recesses for exhausting air oil that are recessed inward in the axial direction of the bearing from the inner diameter surface to the outer diameter surface.

According to this configuration, air oil is supplied from the outside of the bearing through the oil supply hole of the outer ring into the bearing space, and is used for lubricating the bearing. Thereafter, the air oil is smoothly exhausted from the notch recess of the outer ring. Thus, the air oil supplied into the bearing space can be smoothly discharged outside the bearing without staying in the bearing space. For this reason, it is possible to prevent the bearing temperature from being displaced in an unstable manner or excessively rising during operation. Therefore, a spacer provided with a notch for exhaust becomes unnecessary, and the bearings can be used in combination adjacent to each other. In this case, for example, since the bearings can be concentrated and arranged in front of the main shaft, there is an advantage that the main shaft rigidity is increased as compared with the conventional case where the spacer is provided between the bearings.

A circumferential groove communicating with the oil supply hole is provided on the outer diameter surface of the outer ring, and annular grooves are provided on both sides of the circumferential groove on the outer diameter surface of the outer ring. A seal member may be provided. These annular seal members can prevent air oil from undesirably leaking from the outer diameter surface of the outer ring.

¡When combining a plurality of rolling bearings, the circumferential phase of the notch recesses of each bearing may be arranged in the same phase. In this case, a large discharge area, that is, a cross-sectional area of the notch recess can be secured. As a result, the air oil used for lubrication in each bearing is quickly discharged from the notched recess without almost moving into the bearing space of the adjacent bearing. In this way, an effective exhaust and drainage flow can be realized for the air oil. Therefore, the unstable displacement of the bearing temperature can be reliably eliminated.

The inner diameter surface of the outer ring may be formed in a cross-sectional shape that is inclined so that the diameter dimension increases from the rolling surface side toward the width surface side. During the operation of the bearing, the air oil that has been lubricated in the bearing space moves from the inner ring side to the outer ring side due to the centrifugal force generated by the rotation of the inner ring and the exhaust and oil discharge flow accompanying this centrifugal force. A part of the air oil may stay on the inner diameter surface of the outer ring. However, since the inner diameter surface of the outer ring is inclined as described above, the air oil does not stay on the inner diameter surface of the outer ring. It is discharged smoothly.

A counter bore portion may be formed on the outer diameter surface of the inner ring, and a protruding portion protruding toward the outer diameter side may be provided at an axial end portion of the counter bore portion. During the bearing operation, the air oil existing in the vicinity of the protruding portion flows from the inner diameter side portion of the protruding portion along the outer diameter side portion toward the notch concave portion. Therefore, an effective exhaust and exhaust oil flow can be realized.

A counterbore portion is formed on one of the outer diameter surfaces of the inner ring, and an anti-counterbore portion without a counterbore portion is formed on the other, and the anti-counterbore portion is formed from the rolling surface side of the inner ring. You may form in the cross-sectional shape which inclines so that a radial dimension may become large as it goes to the width surface side. During the bearing operation, the air oil present in the counter-counter bore portion flows along the width surface side from the rolling surface side in the inclined surface of the counter-counter bore portion, and moves toward the notch recess. Therefore, an effective exhaust and exhaust oil flow can be realized.

A counter bore portion may be formed on the outer diameter surface of the inner ring, and when a plurality of rolling bearings are combined, an annular member having a diameter larger than the inner ring counter diameter of the counter bore portion may be sandwiched between the bearings. The annular member may have a thin plate shape of, for example, a few millimeters or less. By sandwiching an annular member having a diameter larger than the inner ring counter diameter between the bearings, the air oil used for lubrication in each bearing is blocked by the annular member and moves almost into the bearing space of the adjacent bearing. It is quickly discharged from the notch recess without any problem.

The circumferential phase of the notch recess of the outer ring and the oil supply hole may be arranged in the same phase. In this case, the distance between the supply and discharge oil in the bearing can be made smaller than that obtained by making the circumferential phase of the notch recess and the oil supply hole different from each other, and a more effective exhaust and oil discharge flow can be obtained. be able to. You may provide a chamfer in the corner | angular part of the notch recessed part of the said outer ring | wheel, and the outer-diameter surface of this outer ring | wheel. In this case, the cross-sectional area of the exhaust outlet can be made larger than the cross-sectional area of the exhaust inlet, and a more effective exhaust and exhaust oil flow can be obtained.

The rolling bearing may be an angular ball bearing. It has a cage that holds a plurality of rolling elements at regular intervals in the circumferential direction, and this cage may be an outer ring guide type or a rolling element guide type. For example, in an angular ball bearing used for high-speed rotation, the cage can be prevented from swinging during high-speed rotation by making the cage an outer ring guide type.

The cage is a rolling element guide type, and the outer diameter surface of the cage is formed in a cross-sectional shape that is inclined so that the diameter dimension increases from the pocket side holding the rolling element toward the cage end surface side. May be. During the bearing operation, the air oil existing in the vicinity of the outer diameter surface of the cage flows from the small diameter side to the large diameter side of the inclined surface and smoothly moves toward the notch recess.

The rolling bearing may be a cylindrical roller bearing with an inner ring collar. It has a cage that holds a plurality of rolling elements at regular intervals in the circumferential direction, and this cage may be an outer ring guide type or a rolling element guide type.

The main spindle for machine tools according to the present invention uses a rolling bearing according to any one of the above-described configurations. In this case, the spindle speed can be increased and the temperature rise can be reduced.

Any combination of at least two configurations disclosed in the claims and / or the specification and / or drawings is included in the present invention. In particular, any combination of two or more of each claim in the claims is included in the present invention.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same reference numerals in a plurality of drawings indicate the same or corresponding parts.
(A) is a longitudinal cross-sectional view of the rolling bearing according to the first embodiment of the present invention, and (B) is a plan view of the bearing seen from the direction of arrow A in FIG. 1 (A). (A) is one side view of the outer ring of the rolling bearing, and (B) is another side view of the outer ring. It is a longitudinal cross-sectional view which shows the example which made the rolling bearing the back surface combination. It is a figure which shows the comparative test data of the presence or absence of the notch recessed part of an outer ring | wheel. It is a longitudinal cross-sectional view of the rolling bearing which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing which concerns on 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing which concerns on 4th Embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing which concerns on 5th Embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing which concerns on 6th Embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing which concerns on 7th Embodiment of this invention. (A) is a longitudinal cross-sectional view of a rolling bearing according to an eighth embodiment of the present invention, and (B) is a plan view of the bearing as viewed from the direction of arrow A in FIG. 11 (A). (A) is one side view of the outer ring | wheel of the rolling bearing which concerns on 9th Embodiment of this invention, (B) is the other side view of the outer ring | wheel of the same rolling bearing. (A) is a longitudinal sectional view of a rolling bearing according to a tenth embodiment of the present invention, and (B) is a plan view of the same bearing as viewed from the direction of arrow A in FIG. 13 (A). (A) is a longitudinal cross-sectional view of a rolling bearing according to an eleventh embodiment of the present invention, and (B) is a plan view of the bearing as viewed from the direction of arrow A in FIG. 14 (A). It is a longitudinal cross-sectional view of the main axis for machine tools using the rolling bearing which concerns on any embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing with a nozzle spacer of a prior art example. It is a longitudinal cross-sectional view of the rolling bearing of another conventional example. It is a longitudinal cross-sectional view which shows the example which made the rolling bearing the back surface combination.

A first embodiment of the present invention will be described with reference to FIGS. 1 (A), 1 (B) to 4 (A), (B). The rolling bearing according to this embodiment is used for supporting a machine tool spindle, for example, and is used in air-oil lubrication. However, it is not limited to machine tool spindle applications. As shown in FIG. 1A, the rolling bearing includes an inner ring 1, an outer ring 2, and a plurality of rolling elements 3 interposed between the rolling

surfaces

1a and 2a of the inner and

outer rings

1 and 2. The rolling bearing of this example is an angular ball bearing, and the rolling element 3 is made of a ball. Each rolling element 3 is held in a pocket 4a of a ring-shaped cage 4 at regular intervals in the circumferential direction. As the cage 4, for example, an outer ring guide type guided by the inner diameter surface 2 b of the outer ring 2 is applied.

FIG. 1 (B) is a plan view seen from the direction of arrow A in FIG. 1 (A). As shown in FIG. 1B, the outer ring 2 is provided with an oil supply hole 5 and a circumferential groove 6 for air oil lubrication. The oil supply hole 5 is a through hole that communicates the outer diameter surface 2c of the outer ring 2 and the position in the vicinity of the rolling surface of the outer ring inner diameter surface 2b in the radial direction, and is a hole that supplies air oil into the bearing space. The position in the vicinity of the rolling surface refers to the side of the outer ring inner diameter surface 2b on the opposite side of the rolling element 3 and the outer ring 2 from the center of the rolling element until air oil discharged from the oil supply hole 5 is applied to the rolling element 3. Says the position. The “non-contact side” refers to a side of the outer ring 2 opposite to the biased side of the action line L1 that forms a contact angle with the rolling surface 2a. As shown in FIG. 2A, the oil supply holes 5 are provided at two positions at 180 ° diagonal positions in the outer ring 2.

As shown in FIG. 1B, a circumferential groove 6 is provided on the outer diameter surface 2c of the outer ring 2, and the circumferential groove 6 communicates with the two

oil supply holes

5 and 5, respectively. In other words, the outer circumferential surface 2c of the outer ring 2 is provided so that the circumferential groove 6 passes through a portion where the opening ends of the two

oil supply holes

5 and 5 are located. As shown in FIG. 1 (A), the circumferential groove 6 is formed in an arc-shaped cross section, and for example, is arranged so that the groove bottom position of the circumferential groove 6 matches the central axis of the

oil supply holes

5 and 5. It is installed. Moreover, in this example, it is provided in the circumferential groove | channel 6 so that each opening front-end | tip of the

oil supply holes

5 and 5 may be settled.

As shown in FIG. 1 (A),

annular grooves

7 and 7 are provided at positions on both sides of the circumferential groove 6 on the outer diameter surface 2c of the outer ring 2, respectively. The

annular grooves

7 and 7 are provided with

annular seal members

8 and 8 each composed of an O-ring. That is, by providing the

annular seal members

8 and 8 on both sides of the circumferential groove 6 and the

oil supply holes

5 and 5 between the inner peripheral surface of the housing Hs and the outer diameter surface 2c of the outer ring 2, air oil To prevent leakage.

Notch recesses 9 and 9 for exhausting air oil are provided on both width surfaces of the outer ring 2. As shown in FIGS. 2A and 2B, the notch recesses 9 and 9 on both width surfaces of the outer ring 2 have the same phase and the same shape, and therefore only the notch recesses 9 and 9 on one width surface. The notch recesses 9 and 9 on the other width surface will be described with the same reference numerals and will not be described in detail. The “width surface” may be referred to as an “end surface”.

As shown in FIG. 1A, the notch recesses 9 and 9 on the one width surface are respectively recessed inward in the axial direction of the bearing, and provided from the inner diameter surface 2b to the outer diameter surface 2c of the outer ring 2. Yes. As shown in FIG. 2A, the notch recesses 9 and 9 are disposed at 180 ° diagonal positions of the outer ring 2, and the notch recesses 9 and 9 have the same width dimensions H1 and H1. It is provided to become. The notch recesses 9 and 9 are formed in a concave cross-sectional shape in which the bottom depths D1 and D1 (FIG. 1B) are the same depth. As shown in FIG. 2A, the notched recesses 9 and 9 of the outer ring 2 are provided with a predetermined angle α1 with respect to the phases of the

oil supply holes

5 and 5.

FIG. 3 is a longitudinal sectional view showing an example in which two rolling bearings are combined with the back surface (DB combination) without a spacer. In this example, the circumferential phases of the notch recesses 9 and 9 of each bearing are arranged in the same phase. Here, a comparison test was performed for the presence or absence of the notched recess 9 when the two rolling bearings were combined with the back without a spacer. For each of the combination bearing with a notch recess 9 as a product of this embodiment and the combination bearing without a notch recess as a comparison product, the number of rotations of the bearing is increased step by step with the passage of a predetermined operating time. The relationship between bearing temperature and operation time was compared.

Fig. 4 (A) shows test data of a combination bearing with a notched recess, which is an actual product, and Fig. 4 (B) shows test data of a combination bearing without a notch, which is a comparative product. The cut-out recesses 9 of the product used for the test were provided on both width surfaces of the outer ring 2. Further, two

notches

9 and 9 are provided at 180 ° diagonal positions for each width surface. The size of the notch recess 9 is a bearing having an inner diameter of φ100 mm, a width of 30 mm, and a depth of 2 mm. According to the test results, in the comparative product without a notch recess shown in FIG. 4B, the so-called temperature fluctuation in which the bearing temperature t is displaced in an unstable manner is not eliminated, but the notch recess shown in FIG. In the implementation product provided with 9, the temperature fluctuation of the bearing temperature t is eliminated. Moreover, in the implementation product, there is no excessive temperature rise of the bearing temperature t. In addition, in the size of the notch recess having a width of 30 mm and a depth of 1 mm, temperature fluctuation remains, and it is necessary to secure a certain discharge area. In this test, two

oil supply holes

5 and 5 were provided, and the diameter of each oil supply hole 5 was set to φ1.5 mm. With respect to the oil supply from the oil supply hole 5, the cut-out concave portions 9 of the implemented product are four places of depth 2 mm × width 30 mm.

According to the rolling bearing described above, air oil is supplied from the outside of the bearing through the oil supply hole 5 of the outer ring 2 into the bearing space and used for lubricating the bearing. Thereafter, the air oil is smoothly exhausted from the notch recess 9 of the outer ring 2. Thus, the air oil supplied into the bearing space can be smoothly discharged outside the bearing without staying in the bearing space. For this reason, it is possible to prevent the bearing temperature from being displaced in an unstable manner or excessively rising during operation. Therefore, a spacer provided with a notch for exhaust becomes unnecessary, and the bearings can be used in combination adjacent to each other.

When a plurality of rolling bearings are combined and the circumferential phases of the notched recesses 9 and 9 of each bearing are arranged in the same phase, a large discharge area, that is, a cross-sectional area of the notched recess 9 can be secured. As a result, the air oil used for lubrication in each bearing is quickly discharged from the notched recess 9 without almost moving into the bearing space of the adjacent bearing. In this way, an effective exhaust and drainage flow can be realized for the air oil. Therefore, the unstable displacement of the bearing temperature can be reliably eliminated. Further, by making the cage 4 into the outer ring guide type, the swinging of the cage 4 during high-speed rotation can be further suppressed.

Hereinafter, second to eleventh embodiments of the present invention will be described with reference to FIGS. 5 to 14A and 14B. In the second to eleventh embodiments shown in FIGS. 5 to 14 (A) and (B), the same or corresponding parts as those in the first embodiment shown in FIGS. 1 (A) and (B) are the same. A detailed description thereof is omitted with reference numerals.

First, the second embodiment will be described with reference to FIG. As shown in the figure, the rolling bearings may be combined on the back surface, and the inner diameter surface 2b of the outer ring 2 may be formed in a cross-sectional shape that is inclined so that the diameter dimension increases from the rolling surface side toward the width surface side. . In this example, during the bearing operation, the air oil that has been lubricated in the bearing space moves from the inner ring 1 side to the outer ring 2 side due to the centrifugal force generated by the rotation of the inner ring, the exhaust gas accompanying the centrifugal force, and the oil flow. A part of the air oil may stay on the inner diameter surface 2b of the outer ring 2, but the air oil does not stay on the inner diameter surface 2b of the outer ring 2 because the inner diameter surface 2b of the outer ring 2 is inclined as described above. The liquid is smoothly discharged along the inclined surface 2b.

As in the third embodiment shown in FIG. 6, the rolling bearing having the counter bore portion 10 formed on the outer diameter surface of the inner ring 1 is combined with the back surface, and the axial end portion of the counter bore portion 10 has an outer diameter side. You may provide the protrusion part 11 which protrudes in this. In this example, the air oil existing in the vicinity of the protruding portion 11 flows from the inner diameter side portion of the protruding portion 11 along the outer diameter side portion toward the notch recess 9 during the bearing operation. Therefore, an effective exhaust and exhaust oil flow can be realized.

As in the fourth embodiment shown in FIG. 7, a rolling bearing in which the counter bore portion 10 is formed on the back side and the counter counter bore portion 12 is formed on the front side of the outer diameter surface of the inner ring 1 is combined with the back surface. The counter-bore portion 12 may be formed in a cross-sectional shape that inclines so that the diameter dimension increases from the rolling surface 1a side of the inner ring 1 toward the width surface side. In this example, during the bearing operation, the air oil existing in the counter-counter bore portion 12 flows along the width surface side from the rolling surface 1a side of the inclined surface of the counter-counter bore portion 12 toward the notch recess 9. Therefore, an effective exhaust and exhaust oil flow can be realized.

As in the fifth embodiment shown in FIG. 8, two rolling bearings are combined on the back surface, and an annular member 13 having a diameter larger than the inner ring counter diameter D <b> 2 of the inner ring counter bore portion 10 is sandwiched between the inner ring end faces. It is good as a thing. The annular member 13 is made of a thin steel plate or the like. The inner diameter of the annular member 13 is substantially the same as the inner ring inner diameter, and the outer diameter of the annular member 13 is larger than the inner ring counter diameter D2 and smaller than the inner diameter of the outer ring. It has been established. An annular member 14 made of a thin steel plate or the like is sandwiched between the outer ring end faces. The annular member 14 has the same thickness as the annular member 13 between the inner ring end faces, is larger in diameter than the inner diameter of the outer ring, and is substantially the same as the outer diameter of the outer ring. According to this configuration, by sandwiching the annular member 13 having a diameter larger than the inner ring counter diameter D2 between the end surfaces of the inner ring, air oil used for lubrication in each bearing is blocked by the annular member 13 and adjacent thereto. It is quickly discharged from the notch recess 9 with little movement into the bearing space of the bearing.

In the sixth embodiment shown in FIG. 9, two rolling bearings are combined on the back side, and the cage 4A of each bearing is an outer ring guide type, and the inner diameter surface 4Aa of the cage 4A is held from the pocket 4a side. It is formed in a cross-sectional shape that inclines so that the diameter dimension increases toward the end face of the vessel. In this example, the air oil existing in the vicinity of the inner diameter surface of the cage 4 </ b> A flows along the larger diameter side from the smaller diameter side of the cage inclined surface during the bearing operation, and smoothly moves toward the notch recess 9.

In the seventh embodiment shown in FIG. 10, two rolling bearings are combined in the back, and the cage 4B of each bearing is a rolling element guide type, and the outer diameter surface 4Bb of this cage 4B is connected to the pocket 4a side. It is formed in the cross-sectional shape which inclines so that a radial dimension may become large as it goes to a cage end surface side. The inner diameter surface 4Ba of the cage 4B is also an inclined surface parallel to the outer diameter surface 4Bb. During the bearing operation, the air oil existing in the vicinity of the outer diameter surface and the inner diameter surface of the cage 4B flows from the small diameter side to the large diameter side of each inclined surface, and smoothly moves toward the notch recess 9.

In the eighth embodiment shown in FIGS. 11 (A) and 11 (B), two rolling bearings are combined on the back surface, and at the corners of the notch recess 9 of each outer ring 2 and the outer diameter surface 2c of the outer ring 2. The chamfer 15 is provided. In this case, the cross-sectional area of the exhaust outlet can be made larger than the cross-sectional area of the exhaust inlet, and a more effective exhaust and exhaust oil flow can be obtained.

As in the ninth embodiment shown in FIG. 12A, the circumferential phase of the notch recess 9 and the oil supply hole 5 of the outer ring 2 may be arranged in the same phase. In this case, the distance between the oil supply and discharge oil in the bearing can be made smaller than in the embodiment shown in FIG. 12B in which the circumferential phase of the notch recess 9 and the oil supply hole 5 is different by 90 degrees. Effective exhaust and drainage flow can be achieved.

As in the tenth embodiment shown in FIG. 13A, the outer circumferential surface 2c of the outer ring 2 has no circumferential groove, and as shown in FIG. 13B, the oil supply hole 5 in the outer diameter surface 2c is formed. An annular groove 16 may be provided in the outer peripheral portion of the exhaust outlet. The annular groove 16 is provided with an annular seal member 8A made of an O-ring for preventing air oil leakage. In this case, the number of processing steps can be reduced and the number of parts can be reduced as compared with the case where the two

circumferential grooves

6 and 6 are formed.

As in the eleventh embodiment shown in FIGS. 14A and 14B, the rolling bearing may be a cylindrical roller bearing with an inner ring collar. In this case, the axial position of the oil supply hole 5 in the outer ring 2 is provided so as to match the one end surface 3 a of the rolling element 3. As a result, the air oil can be reliably guided to the cage pocket 4a and the collar surface 1c of the inner ring 1, and the lubrication effect can be enhanced. In addition, the same operational effects as the above-described embodiments are obtained.

In each of the above embodiments, as an example of the combination of the angular ball bearings, an example in which a rear combination is used is shown, but a front combination or a parallel combination may be used. The outer ring guide type cage may be changed to a rolling element guide type cage, and conversely, the rolling element guide type cage may be changed to an outer ring guide type.

FIG. 15 is a longitudinal sectional view of a main spindle for a machine tool using the rolling bearing according to any one of the above embodiments. The example of FIG. 15 is a so-called built-in motor driven spindle for a machine tool in which a motor is built in a housing. A rotor 19 of a motor 18 is attached to the main shaft 17, and a stator 20 of the motor 18 is attached to the housing Hs. The rotor 19 is made of a permanent magnet or the like, and the stator 20 is made of a coil, a core, or the like. The cylindrical roller bearing BR1 according to the embodiment and the angular ball bearing BR2 combined with the back surface are arranged on the front end side of the main shaft 17, and the cylindrical roller bearing BR1 according to the embodiment is also arranged on the rear end side of the main shaft 17.

The inner ring 1 of each bearing BR1, BR2 is fitted to the outer circumferential surface of the main shaft 17, and the outer ring 2 is fitted to the inner circumferential surface of the housing Hs. These inner and

outer rings

1 and 2 are fixed to the main shaft 17 and the housing Hs by an inner ring presser 21 and an outer ring presser 22, respectively. An air oil supply path 23 is provided in the housing Hs, and the air oil supply path 23 is connected to an air oil supply source (not shown). The air oil supply path 23 communicates with the oil supply hole 5 of each outer ring 2. The housing Hs is provided with an air oil exhaust groove 24 communicating with the notched recess 9 of each outer ring 2 and an air oil exhaust passage 25 connected to each air oil exhaust groove 24. Air oil is exhausted from the air oil exhaust passage 25. In this case, since the bearings can be concentrated on the front end side of the main shaft 17, the main shaft 17 can be shortened and the main shaft rigidity can be increased as compared with the conventional case where the spacer is provided between the bearings. it can. At the same time, it is possible to prevent the bearing temperature from being unstablely displaced or to raise the temperature excessively, so that the speed and accuracy of the main shaft 17 can be increased.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily assume various changes and modifications within the obvious scope by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ...

Outer ring

1a, 2a ... Rolling surface 2b ... Inner diameter surface 2c ... Outer diameter surface 3 ... Rolling element 5 ... Oil supply hole 6 ... Circumferential groove 7 ...

Annular groove

8, 8A ... Seal member 10 ... Counter bore part DESCRIPTION OF SYMBOLS 11 ... Projection part 12 ... Counter-bore part 13 ... Ring member 15 ... Chamfer

Claims

A rolling bearing with rolling elements interposed between the rolling surfaces of the inner ring and the outer ring,
The outer ring is provided with an oil-oil lubrication hole penetrating into the bearing space, and either or both of the width surfaces of the outer ring have a notch recess for exhausting air oil that is recessed inward in the axial direction of the bearing. Rolling bearing provided from the surface to the outer diameter surface.
2. The outer ring according to claim 1, wherein a circumferential groove communicating with the oil supply hole is provided on the outer diameter surface of the outer ring, and annular grooves are respectively provided on both sides of the circumferential groove on the outer diameter surface of the outer ring. Rolling bearings each provided with an annular seal member in the groove.
2. The rolling bearing according to claim 1, wherein when the plurality of rolling bearings are combined, the circumferential phases of the notch recesses of the bearings are arranged in the same phase.
2. A rolling bearing according to claim 1, wherein the inner ring surface of the outer ring is formed in a cross-sectional shape that is inclined so that the diameter dimension increases from the rolling surface side toward the width surface side.
2. A rolling bearing according to claim 1, wherein a counter bore portion is formed on the outer diameter surface of the inner ring, and a protruding portion protruding toward the outer diameter side is provided at an axial end portion of the counter bore portion.
In Claim 1, a counterbore part is formed in any one of the outer diameter surfaces of the inner ring, and an anti-counterbore part without a counterbore part is formed on the other, and the anti-counterbore part is formed on the inner ring. A rolling bearing formed in a cross-sectional shape that is inclined so that the diameter dimension increases from the rolling surface side toward the width surface side.
2. The counter bore portion according to claim 1, wherein a counter bore portion is formed on the outer diameter surface of the inner ring, and an annular member having a larger diameter than the inner ring counter diameter of the counter bore portion is provided between the bearings when a plurality of rolling bearings are combined. Rolling bearing.
2. The rolling bearing according to claim 1, wherein the circumferential phase of the notch recess and the oil supply hole of the outer ring are arranged in the same phase.
2. The rolling bearing according to claim 1, wherein a chamfer is provided at a corner between the notch recess of the outer ring and the outer diameter surface of the outer ring.
The rolling bearing according to claim 1, wherein the rolling bearing is an angular ball bearing.
11. A rolling bearing according to claim 10, further comprising a cage for holding a plurality of rolling elements at regular intervals in the circumferential direction, wherein the cage is an outer ring guide type or a rolling element guide type.
12. The cage according to claim 11, wherein the cage is of a rolling element guide type, and the outer diameter surface of the cage is inclined so that the diameter dimension increases from the pocket side holding the rolling element toward the cage end surface side. Rolling bearing with a cross-sectional shape.
2. The rolling bearing according to claim 1, wherein the rolling bearing is a cylindrical roller bearing with an inner ring collar.
14. A rolling bearing according to claim 13, further comprising a cage for holding a plurality of rolling elements at regular intervals in the circumferential direction, wherein the cage is an outer ring guide type or a rolling element guide type.
A spindle for a machine tool using the rolling bearing according to claim 1.