JP5347538B2 - Angular contact ball bearings for spindle equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle device bearing having a favorable oil draining property for suppressing the excessive supply of lubricating oil to the bearing and the abnormal heating of the bearing. <P>SOLUTION: In an outer ring 71 of the spindle device bearing 70, an oil supply hole 78 and oil drain holes 71a, 71b are formed passing therethrough in the radial direction. The suction force of a negative pressure generating device 103 generates negative pressure in the oil drain holes 71a, 71b. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention relates to an angular contact ball bearing for a spindle device, and more particularly to an angular contact ball bearing for a spindle device capable of high-speed rotation, which is applied to a multi-axis control machine tool or the like and is supplied with lubricating oil from the outside.

  For example, in a multi-axis controlled machine tool such as a 5-axis machine or a multi-task machine tool, the rotary shaft to which the tool is attached can turn between a horizontal position and a vertical position or 360 degrees. A tilt type spindle device is used.

  In such a spindle device, as a method of lubricating a bearing disposed inside, an oil-air lubrication method or an oil mist lubrication method that supplies a small amount of lubricating oil from the outside to the inside of the bearing using air, or a lubricating oil A direct injection method is employed in which the nozzle is directly injected into the bearing intermittently at a high speed.

For example, in oil-air lubrication or oil mist lubrication, as shown in FIG. 12 , the lubricating oil is supplied from the nozzle 901 to the bearing 900, and from the oil drain holes 903a and the oil drain grooves 903b formed in the outer ring 900a and the spacer 902. A structure in which the oil is discharged to the outside through an oil drain passage 905 of the housing 904 is known (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 63-139324 (FIG. 3)

  By the way, in the spindle device for machine tools described in Patent Document 1, the lubricating oil is naturally discharged through the oil discharge passage 905 of the housing 904 due to the gravitational action. There is a possibility that the lubricating oil used in the exhaust may not be exhausted. In particular, in a spindle device capable of high-speed rotation with dm · N 500,000 or more, and dm · N 1,000,000 or more, where the amount of residual oil in the bearing is sensitive to lubrication conditions, excessive heat generation and excessive stirring oil can cause abnormal heat generation. There is sex. In addition, when applied to a tilt type spindle device, the lubricating oil discharged into the oil drain hole 903a or the oil drain groove 903b is returned to the inside of the bearing due to a change in the posture of the spindle device, resulting in excessive lubricating oil or stirring resistance. May cause abnormal heat generation.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an angular contact ball for a spindle device that has a simple configuration, good oil drainage, and can suppress excessive lubricating oil and abnormal heat generation. It is to provide a bearing.

The above object of the present invention can be achieved by the following constitution.
(1) an inner ring having an inner ring raceway surface on the outer peripheral surface;
An outer ring having an outer ring raceway surface on the inner circumferential surface;
A plurality of balls arranged with a contact angle between the inner ring raceway surface and the outer ring raceway surface;
An outer ring guide retainer for retaining the plurality of balls at substantially equal intervals;
An angular contact ball bearing for a spindle device that is rotatably supported with respect to a housing and is lubricated by oil lubrication.
The internal space of the bearing is a sealed structure,
The outer ring, the oil supply hole that will be formed through the radially formed through the radial direction and the oil discharge hole is provided which opens in the inner peripheral surface of the counter bore,
The oil supply hole and the oil discharge hole open on an inner peripheral surface of the outer ring where the retainer is not guided,
The opening of the oil drainage hole has an inner end in the axial direction located between the outer ring raceway surface and an inner end surface in the axial direction of the pocket of the retainer, and an outer end in the axial direction of the retainer in the axial direction of the retainer. Arranged in the vicinity of the outer ring raceway surface so as to be located on the inner side in the axial direction from the outer end surface,
An angular contact ball bearing for a spindle device, wherein a negative pressure is applied to the oil drainage hole by a suction force from the outside of the bearing.
(2) The oil supply hole and the oil discharge hole are open on the inner side in the axial direction of the retainer and on the inner peripheral surface of the outer ring where the retainer is not guided (1). Angular contact ball bearings for spindle devices described in 1.
(3) pre-Symbol refueling hole, with respect to the axial center position of the ball, on the opposite side of the contact point where the ball and the outer ring raceway surface are in contact, and, the position deviated in the axial direction from the axial center position Open to
The oil drainage hole is opened in the inner peripheral surface of the outer ring that overlaps with the ball as seen from the radial direction,
The angular ball bearing for a spindle device according to (1) or (2), wherein the cage is guided on an inner peripheral surface of the outer ring on the counter-counter bore side.

According to the angular contact ball bearing for the spindle device of the present invention, since a negative pressure is applied to the oil drainage hole formed in the outer ring by the suction force from the outside of the bearing, excess lubricating oil inside the bearing is removed from the oil drainage hole. It can be discharged quickly via In particular, in the tilt type spindle device, even if the posture changes, the lubricating oil in the drainage hole that should be discharged is prevented from returning to the raceway surface, and excessive lubricating oil and abnormal heat generation are suppressed. be able to.

  Further, since the oil supply hole penetrating in the radial direction is provided in the outer ring, it is not necessary to separately provide a nozzle outside the bearing, and the lubricating oil can be supplied into the bearing with a simple configuration.

  Further, since the inner space of the bearing is sealed, the suction of air from the side of the bearing is suppressed, and the lubricating oil in the inner space of the bearing can be sucked effectively. The term “sealing” as used in the present invention includes a portion sealed by a labyrinth seal on the side of the bearing, and excludes a portion opened to the outside by an oil supply hole or an oil drain hole.

1 is a schematic view of a portal machining center to which a spindle device including a bearing of the present invention is applied. In the spindle device to which the bearing of the first embodiment is applied, it is a cross-sectional view showing an oil supply passage and an oil discharge passage of one front bearing. FIG. 4 is a cross-sectional view showing an oil supply passage and an oil discharge passage of the other front bearing in the spindle device. In a main shaft device, it is a sectional view showing an oil supply passage and an oil discharge passage of a rear bearing. It is an expanded sectional view of the front side bearing of a main shaft device. It is an expanded sectional view of the rear bearing of a main shaft device. It is an expanded sectional view of the front side bearing which concerns on the spindle apparatus bearing of 2nd Embodiment. It is sectional drawing of the main axis | shaft apparatus which shows the modification of an oil supply path and an oil discharge path. The relationship between the bearing rotational speed and the bearing outer ring temperature rise in the present invention product and the conventional product is shown. It is a figure for demonstrating the turning state of a spindle. It is a graph which shows the outer ring | wheel temperature at the time of turning a spindle at the time of 40,000min- ¹ driving | operation. It is sectional drawing in the conventional main axis | shaft apparatus.

(First embodiment)
Hereinafter, a spindle device bearing according to a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a portal machining center as a multi-tasking machine tool in which a spindle device having a bearing of this embodiment is incorporated. In the portal machining center 1, a table 3 is supported on a bed 2 so as to be movable in the X-axis direction, and a pair of columns 4 are erected on both sides of the bed 2. A cross rail 5 is installed on the upper end of the column 4, and a saddle 6 is provided on the cross rail 5 so as to be movable in the Y-axis direction. The saddle 6 supports a ram 7 that can be moved up and down in the Z-axis direction. A spindle that holds the spindle device 20 at the lower end of the ram 7 so as to be capable of rotational indexing around the Y axis and the Z axis. A head 8 is attached.

  The spindle head 8 is provided with a pair of support arms 9 so as to sandwich the bracket 21 of the spindle device 20. The pair of support arms 9 has a pair of swivel shafts (not shown) fixed to both side surfaces of the bracket 21. Support for rotation. Thus, the spindle device 20 can be swiveled around the Y axis with respect to the pair of support arms 9 by a drive mechanism (not shown) provided on the spindle head 8 side, and between the horizontal position and the vertical position, or 360 A tilt type capable of changing the mounting posture over the entire range is constructed.

  As shown in FIG. 2, the spindle device 20 is a motor built-in system, and a hollow rotary shaft 22 is provided at the axial center, and a draw bar 23 slides on the axis of the rotary shaft 22. It is freely inserted. The draw bar 23 urges the pull stud 25 attached to the tool holder 24 in the counter tool side direction (right direction in the figure) by the force of the disc spring 27 via the clamp ball 26. It fits with the tapered surface 28 of the rotating shaft 22. A tool (not shown) is attached to the tool holder 24. As a result, the rotary shaft 22 clamps the tool at one end (the left side in the figure) so that the tool can be attached.

  The rotary shaft 22 is fixed to the bracket 21 (see FIG. 1) by two rows of front bearings 60 and 70 that support the tool side and a row of rear bearings 80 that support the opposite tool side. Further, the outer cylinder 29 constituting the housing H is rotatably supported. The front bearings 60 and 70 and the rear bearing 80 constitute the spindle device bearing of the present embodiment.

  On the outer peripheral surface of the rotary shaft 22 between the front bearings 60 and 70 and the rear bearing 80, a rotor sleeve 31 on which the rotor 30 is shrink-fitted is fitted. The stator 32 disposed around the rotor 30 is fixed to the outer cylinder 29 by fitting a cooling jacket 33 shrink-fitted into the stator 32 into the outer cylinder 29. Therefore, the rotor 30 and the stator 32 constitute a motor, and by supplying electric power to the stator 32, a rotational force is generated in the rotor 30 and the rotating shaft 22 is rotated.

  Further, a tool unclamp cylinder 36 constituting the housing H in which a tool unclamp piston 35 is slidably fitted is fixed to the rear cover 34 constituting the housing H fixed to the outer cylinder 29 and the non-tool side. ing. Therefore, when exchanging the tool, the hydraulic oil is guided from the oil passage 37 to the hydraulic chamber 38 and the tool unclamp piston 35 is advanced to the tool side (left side in the figure), so that the drawbar 23 is moved to the tool side (in the figure). Advance to the left) to unclamp the tool.

  The front bearings 60, 70 are outer rings 61, 71, inner rings 62, 72, balls 63, 73 as rolling elements arranged with contact angles, and outer ring guides that hold the balls 63, 73 at substantially equal intervals. Angular ball bearings having a pair of seal members 65 and 75 which are attached to both axial sides of the outer rings 61 and 71 and seal the internal spaces of the bearings 60 and 70, respectively. Arranged to be a combination. The rear bearing 80 is a cylindrical roller bearing having an outer ring 81, an inner ring 82, a cylindrical roller 83 as a rolling element, and an outer ring guide retainer 84 that holds the cylindrical roller 83 at substantially equal intervals.

  Outer rings 61, 71 of the front bearings 60, 70 are fitted in the outer cylinder 29, and are axially directed to the outer cylinder 29 via the outer ring spacer 40 by a front bearing outer ring presser 39 bolted to the outer cylinder 29. It is fixed to. Further, the inner rings 62 and 72 of the front bearings 60 and 70 are fitted on the rotating shaft 22 and are axially connected to the rotating shaft 22 via the inner ring spacer 42 by the nut 41 fastened to the rotating shaft 22. It is fixed.

  An outer ring 81 of the rear bearing 80 is fitted in the rear lid 34 and is fixed to the rear lid 34 by a rear bearing outer ring presser 43 that is bolted to the rear lid 34. The inner ring 82 of the rear bearing 80 is taper-fitted to a tapered surface 44 formed on the rotating shaft 22, and the other ring 45 fastened to the rotating shaft 22 is used to cover the inner ring spacer 46 and the speed sensor 47. Positioning is performed via the detection unit 48. Further, the inner peripheral surface of the rear cover 34 and the inner peripheral surface of the rear bearing outer ring retainer 43 are arranged opposite to each other in the vicinity of the outer peripheral surface of each spacer 46 to form a labyrinth seal. Seal.

  Note that a detection unit 49 of the speed sensor 47 is fixed to a position opposite to the detection unit 48 in the radial direction on the side opposite to the tool of the rear bearing outer ring presser 43 and detects the rotation speed of the rotary shaft 22. A front cover 50 is bolted to the tool side end surface of the front bearing outer ring presser 39.

  Here, as shown in FIGS. 2 to 4, the outer cylinder 29, the rear lid 34, and the tool unclamping cylinder 36 constituting the housing H are used for lubricating the front bearings 60 and 70 and the rear bearing 80, respectively. A plurality of oil supply passages (oil supply holes in the housing H) 90, 91, 92 are formed, and a lubrication device 93 that feeds the lubricant oil is provided to one end side of these passages 90, 91, 92 via a pipe (not shown). Each is attached. The lubrication system supplied by the lubrication device 93 may be oil lubrication, and may be any of oil-air lubrication, oil mist lubrication, direct injection lubrication, and the like.

  For example, in the case of oil-air lubrication, the other end sides of the oil supply passages 90, 91, 92 are provided with oil supply holes 68 (see FIG. 2), 78 (see FIG. 3), 88 (see FIG. 3) formed in outer rings 61, 71 described later. The lubricating oil sent by the lubricating device 93 is supplied into the bearing space from the outer ring oil supply holes of the bearings 60, 70, 80.

  Further, the housing H has a plurality of oil drain passages (oil drain holes of the housing H) 100 (see FIG. 2) and 101 (see FIG. 3) through which the lubricating oil that lubricates the bearings 60, 70, and 80 is discharged. ), 102 (see FIG. 4) are formed, and a negative pressure generator 103 for sucking lubricating oil is connected to one end side of each of the passages 100, 101, 102 via pipes (not shown). Has been.

  Specifically, as shown in an enlarged view in FIG. 5, in the front side bearing 70, a plurality of balls 73 are formed on the inner peripheral surface of the outer ring 71, the outer ring raceway surface 71 c having a substantially arc-shaped cross section, and the outer periphery of the inner ring 72. A contact angle with respect to the radial direction is arranged between the inner ring raceway surface 72a formed on the surface and having a substantially arc-shaped cross section. The outer ring 71 of the front bearing 70 is provided with an oil supply hole 78 penetratingly formed in the radial direction. The oil supply hole 78 is an axial center position O of the ball 73 on the outer ring raceway surface 71c having a substantially arc-shaped cross section. On the other hand, the ball 73 and the outer ring raceway surface 71c are on the side opposite to the contact point P1 and open at a position deviating from the axial center position O in the axial direction.

  An annular circumferential groove 79 is formed on the outer peripheral surface of the outer ring 71 at an axial position where the oil supply hole 78 opens. Thereby, the lubricating oil supplied from the oil supply passage 91 (see FIG. 3) formed in the outer cylinder 29 passes through the circumferential groove 79 and the oil supply hole 78, and the balls 73, the outer ring raceway surface 71c, and the inner ring raceway surface. It is supplied to a position close to the contact points P1, P2 with the 72a.

  The outer ring 71 has oil drain holes 71a and 71b that open in the vicinity of the outer ring raceway surface 71c through which the balls 73 pass on the inner peripheral surface on the counterbore side and the counter counterbore side, and penetrate in the radial direction. Are formed at substantially equal intervals in the circumferential direction.

On the inner peripheral surface of the outer ring 71, oil collecting grooves 76a and 76b are formed in the circumferential direction at axial positions where the oil drain holes 71a and 71b are opened. In addition, annular circumferential grooves 77a and 77b in which the oil drain holes 71a and 71b are respectively opened are formed on the outer peripheral surface of the outer ring 71. The circumferential grooves 77a and 77b are formed in the oil drain holes 71a and 77b, respectively. 71b and oil drain holes 29a and 29b of the oil drain passage 101 formed in the outer cylinder 29 are communicated with each other. The oil collecting grooves 77a and 77b, which are the inner peripheral side openings of the oil drain holes 71a and 71b, are preferably opened in the vicinity of the outer ring raceway surface 71c as shown in FIG. Furthermore, it is more preferable that the oil collecting grooves 77a and 77b are respectively formed at positions that overlap with the balls 73 when viewed from the radial direction. As a result, there is an advantage that after the rolling contact portion is lubricated, the oil adhering to the ball 73 is directly shaken off by the centrifugal force and then directly guided to the oil drain holes 71a and 71b. However, the oil collecting grooves 77a and 77b are not limited to positions that overlap with the balls 73 when viewed from the radial direction. In each of the embodiments shown in FIGS. 5, 6, and 7 , the oil supply hole and the oil discharge hole are shown in the same cross section for simplification, but are actually arranged in different phases. .

  The retainer 74 is an outer ring guide retainer that retains the balls 73 at substantially equal intervals, and is formed to be substantially line symmetrical in the axial direction. The cage 74 includes a pair of annular portions 74a and 74b located on both sides in the axial direction, and a plurality of column portions 74c that connect the annular portions 74a and 74b and are arranged at substantially equal intervals in the circumferential direction. The ring portions 74a and 74b and the adjacent column portion 73c constitute a pocket for holding the ball 73. Further, the retainer 74 has a clearance portion by setting the inner peripheral portion of the outer peripheral surface of the column portion 74c and the outer peripheral surfaces of the annular portions 74a and 74b to be smaller in diameter than the outer portion of the outer peripheral surface of the annular portions 74a and 74b. 74d is formed.

  As a result, the retainer 74 has an outer portion of the outer peripheral surface of the annular portion 74a and an inner peripheral surface of the outer ring 71 over the oil collecting groove 76a of the oil drain hole 71a as viewed from the radial direction on the counter-bore side. The outer ring is guided by sliding contact at a position where it does not overlap. Therefore, the annular portion 74a, which is the guide surface of the cage 74, is not scraped by the opening edge of the oil collecting groove 76a, and wear of the cage 74 is prevented. The front bearing 60 has the same configuration as that of the front bearing 70 arranged in combination with the front bearing 70 and the back surface, and thus the description thereof is omitted.

  As shown in FIG. 6, the rear bearing 80 includes a plurality of cylindrical rollers 83, an outer ring raceway surface 81 c formed on the inner peripheral surface of the outer ring 81, and an inner ring raceway surface formed on the outer peripheral surface of the inner ring 82. 82a. The outer ring 81 is provided with an oil supply hole 88 penetrating in the radial direction, and the oil supply hole 88 opens in the vicinity of one side of the outer ring raceway surface 81 c that does not interfere with the cylindrical roller 83.

  An annular circumferential groove 89 is formed on the outer circumferential surface of the outer ring 81 at an axial position where the oil supply hole 88 opens. As a result, the lubricating oil supplied from the oil supply passage 92 (see FIG. 4) formed in the rear lid 34 passes through the circumferential groove 89 and the oil supply hole 88, and the cylindrical roller 83, the outer ring raceway surface 81c, and the inner ring raceway. It is supplied to the rolling surface with the surface 82a.

  The outer ring 81 is formed with a plurality of oil drain holes 81a penetrating in the radial direction at substantially equal intervals in the vicinity of the other side of the outer ring raceway surface 81c that does not interfere with the cylindrical roller 83. An annular oil collecting groove 86 formed in the circumferential direction is formed on the inner peripheral surface at the axial position where the oil drain hole 81a opens. An annular circumferential groove 87 is formed in the outer peripheral surface of the outer ring 81 and the oil drain holes 81a are opened. The circumferential grooves 87 are formed in the oil drain hole 81a and the rear lid 34. The oil discharge passage 102 communicates with the oil discharge hole 34a.

  The cage 84 includes a pair of annular portions 84a and 84b located on both sides in the axial direction, and a plurality of column portions 84c that connect the annular portions 84a and 84b and are arranged at substantially equal intervals in the circumferential direction. These annular portions 84a and 84b and the adjacent column portion 83c constitute a pocket for holding the cylindrical roller 83. Further, the retainer 84 also has a relief portion by making the inner part of the outer peripheral surface of the column part 84c and the outer peripheral surface of both annular parts 84a, 84b smaller than the outer part of the outer peripheral surface of the annular parts 84a, 84b. 84d is formed. Thereby, the retainer 84 is guided to the outer ring at the outer portion of the outer peripheral surface of the annular portions 84a and 84b.

  In addition, oil drain holes 34b and 43a communicating with the internal space of the bearing 80 are formed in the axially inner end portion closer to the bearing than the portion constituting the labyrinth seal of the rear lid 34 and the rear bearing outer ring retainer 43, respectively. Yes. The oil drain hole 34 b has an opening on an inner peripheral surface having an inner diameter equal to or larger than the inner diameter of the axial end surface of the outer ring 81, and is formed to communicate directly with the oil drain passage 102. The oil drain hole 43a is also formed to have an opening on the inner peripheral surface having an inner diameter equal to or larger than the inner diameter of the axial end surface of the outer ring 81 and to be inclined away from the bearing 80 radially outward. Further, the oil drainage hole 43 a communicates with the oil drainage passage 102 via an annular circumferential groove 43 b formed on the outer peripheral surface of the oil drainage hole 43 a and the oil drainage hole 34 c of the rear lid 34.

  Accordingly, the lubricating oil in the oil drain holes 71a, 71b, 81a, 43a, which lubricated the bearings 60, 70, 80, is connected to the circumferential grooves 77a, 77b, 87, 43b and the oil drain passages 100, 101, 102, respectively. In addition, the lubricating oil in the oil drain hole 34b is discharged to the outside through the oil drain passage 102. At this time, a negative pressure acts in the oil drain holes 71a, 71b, 81a, 34b, 43a by the suction force from the outside of the bearing, that is, the suction force of the negative pressure generator 103, and the oil drain holes 71a, 71b. , 81a, 34b, 43a is forcibly sucked. Further, the lubricating oil adhering to the inner peripheral surfaces of the outer rings 61, 71, 81 in the vicinity of the outer ring raceway surfaces 61 c, 71 c, 81 c is also drained holes 71 a, 71 b, 81 a, 34b and 43a.

  As a result, the oil drain holes 71a, 71b, 81a provided in the vicinity of the outer ring raceway surfaces 61c, 71c, 81c of the bearings 60, 70, 80, and the oil drain holes 34b of the rear lid 34 and the rear bearing outer ring presser 43 are provided. , 43a, the excess lubricating oil can be quickly discharged. In particular, in the tilt-type main spindle device 20 as in the present embodiment, even when the posture changes, the lubricating oil that should be discharged returns to the inside of the bearing, in particular, the oil drain holes 71a, 71b, The lubricating oil present in 81a, 34b, 43a is prevented from returning to the outer ring raceway surfaces 61c, 71c, 81c, and abnormal heat generation due to excessive lubricating oil and stirring resistance can be suppressed.

  Further, since the oil supply holes 78 and 88 penetrating in the radial direction are provided in the outer rings 61, 71 and 81, it is not necessary to separately provide a nozzle outside the bearings 60, 70 and 80, and the lubricating oil can be provided with a simple configuration. Can be fed into the bearing.

  Further, since the internal space of the bearings 60, 70, 80 is sealed by a pair of seal members 65, 75 and a labyrinth seal between the rear lid 34 and the rear outer ring presser 43, air suction from the side of the bearing is suppressed. Thus, the lubricating oil in the internal space of the bearings 60, 70, 80 can be sucked effectively.

  Furthermore, since the oil collecting grooves 76a, 76b, 86 are formed in the circumferential direction on the inner peripheral surfaces of the outer rings 61, 71, 81 at axial positions where the oil drain holes 71a, 71b, 81a are opened, Lubricating oil that adheres to the inner peripheral surfaces of the outer rings 61, 71, 81 and lubricates the bearings 60, 70, 80 is collected in the oil collecting grooves 76 a, 76 b, 86, and further in the oil collecting grooves 76 a, 76 b, 86. The lubricating oil is quickly discharged into the oil drain holes 71a, 71b, 81a by the suction force of the negative pressure generator 103. As a result, oil drainage can be further improved, and excessive lubricating oil and abnormal heat generation can be further suppressed.

  When the bearings 60, 70, and 80 are rotating at high speed, the internal air is also affected by the viscous resistance when the balls 63 and 73 and the cylindrical rollers 83 are revolved and the cages 74 and 84 and the inner rings 72 and 82 are rotated. The air flow in the circumferential direction is generated. Therefore, the oil adhering to the inner peripheral surfaces of the outer rings 61, 71, 81 is also moved in the circumferential direction along the inner peripheral surface. In particular, when the rotary shaft 22 is a vertical shaft, the oil movement is likely to occur because the gravity effect is small. Therefore, if there are oil collecting grooves 76a, 76b, 86, oil is easily collected in the oil collecting grooves 76a, 76b, 86, and the oil drainage is improved. Accordingly, the oil collecting grooves 76a, 76b, 86 may be any of a square cross section, an arc shape, and a taper shape, but an arc shape is more preferable than a square shape.

  In addition, circumferential grooves 77 a, 77 b, 87 and oil supply holes 78 communicating the oil drain holes 71 a, 71 b, 81 a and the oil drain passages 100, 101, 102 of the housing H are formed on the outer peripheral surfaces of the outer rings 61, 71, 81. , 88 and the circumferential grooves 79, 89 communicating with the oil supply passages 90, 91, 92 of the housing H are formed, so that the phase alignment of the oil discharge passages 100, 101, 102 and the oil supply passages 90, 91, 92 is achieved. The bearings 60, 70, 80 can be assembled to the housing H without performing the above, and the assemblability of the spindle device 20 is improved.

  In the present embodiment, the oil drain passages 100, 101, 102 are formed for each of the bearings 60, 70, 80. Therefore, by changing the suction capacity condition of the negative pressure generator 103, each bearing 60, The suction efficiency of 70, 80 can be optimized.

(Second Embodiment)
Next, a spindle device bearing according to a second embodiment of the present invention will be described in detail with reference to FIG. In addition, in this embodiment, the structure of the angular ball bearing side which is a front side bearing differs from 1st Embodiment. For this reason, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified.
Further, in each embodiment relating to the angular ball bearing described below, among the double-row front bearings, the angular ball bearing on the counter tool side is described, and the angular ball bearing on the tool side has the same configuration. Description is omitted.

As shown in FIG. 7 , the angular ball bearing 270 of this embodiment is not provided with a pair of seal members, but the outer peripheral surfaces of the flanges 42 a and 42 a of the inner ring spacers 42 provided on both sides of the bearing 270. The inner circumferential surface of each outer ring spacer 40 constitutes a labyrinth seal, and the internal space of the bearing 270 is sealed. Further, in the outer ring 271 of the angular ball bearing 270, inclined oil drain holes 71b, oil collecting grooves 76b, and circumferential grooves 77b are formed only on the counterbore side.

Therefore, also in this embodiment, since the internal space of the bearing 270 is sealed by the labyrinth seal between the flange 42a of each inner ring spacer 42 and each outer ring spacer 40, the suction of air from the bearing side is suppressed. The lubricating oil in the internal space of the bearing 270 can be sucked effectively .
Other configurations and operations are the same as those in the first embodiment.

In addition, this invention is not limited to each embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In this embodiment, the front bearings 60 and 70 are two rows of angular ball bearings, and the rear bearing 80 is a cylindrical roller bearing. However, the type and number of rows of each bearing can be arbitrarily set.
In the present embodiment, the oil drain holes 71a and 71b of the angular ball bearing and the oil drain holes 81a of the cylindrical roller bearing are formed in a plurality in the circumferential direction, but at least one is formed in the circumferential direction. That's fine.

Further, as in the machine tool spindle device 20a shown in FIG. 8 , the oil drain holes of the bearings 60, 70, 80 communicate with a single oil drain passage 110 formed in the housing H, and this oil drain passage. 110 may be connected to the negative pressure generator 103 via a pipe (not shown).

As a result, the lubricating oil that has lubricated the bearings 60, 70, and 80 is forcibly sucked by the suction force of the negative pressure generating device 103, and then flows from the single drainage passage 110 to the outside via the drainage hole. Excessive lubricating oil and abnormal heat generation inside the bearing can be suppressed. In addition, the number of oil drain passages drilled in the housing H can be reduced, and the processing cost can be reduced. In FIG. 8 , the oil supply passages 90 and 91 of the front bearings 60 and 70 having different phases and the oil supply passage 92 of the rear bearing 80 are shown in the same cross section.

  In the present embodiment, a plurality of oil supply passages 90, 91, 92 are provided for each of the bearings 60, 70, 80. However, the spindle device 20 is configured by using these oil supply passages 90, 91, 92 as a single oil supply passage. It may be possible to supply it by branching the inside thereof, and an optimum method can be selected as to whether a separate passage or a single common passage is used for each of the plurality of bearings depending on the lubrication method and lubrication conditions.

  Here, during operation using the spindle device of the present invention (product of the present invention) shown in the first embodiment (the front bearing of FIG. 5 and the rear bearing of FIG. 6) and the conventional spindle device (conventional product). The temperature rise of the bearing was measured. The test conditions are listed below.

<Test conditions>
(1) Main shaft bearing type: Angular contact ball bearing (2) Bearing main dimensions: Bearing inner diameter 50 mm, bearing outer diameter 80 mm
(3) Spindle speed during testing: Max. 40,000 min ⁻¹ (Bearing dm · N value: 2.
6 × 10 ⁶ )
(4) Lubrication method: Oil-air lubrication (5) Oil draining method / Invention product: With suction from drain hole (with negative pressure suction)
・ Conventional product: No suction from the oil drain hole (only gravity discharge: atmospheric pressure conditions)

FIG. 9 shows the relationship between the bearing rotational speed and the bearing outer ring temperature rise in the product of the present invention and the conventional product. As can be seen from FIG. 9 , in the product of the present invention, the temperature rise value of the bearing outer ring is lowered with the increase in the rotational speed, compared with the conventional product, and in particular, at a high speed rotation of 20,000 min ⁻¹ or more, about 3 It is about 4 ° C lower.

  This is because the lubricating oil supplied to the bearing is smoothly discharged without stagnation inside the bearing without being affected by gravity due to suction from the oil drain hole. If oil stagnates inside the bearing in high-speed operation, the temperature rise due to agitation resistance may suddenly occur, and the oil film thickness at the rolling contact portion becomes thinner due to a decrease in the viscosity of the lubricating oil during heat generation. Seizure occurs instantaneously from contact. The product of the present invention can significantly reduce the risk of seizure in the structure of a high-speed spindle or a rotary spindle.

Next, the spindle was turned during high-speed rotation, and the suction effect from the oil drain hole was confirmed. As shown in FIG. 10 , the turning cycle was started from a state where the spindle was in a horizontal state (rotation axis is horizontal: phase is 0 °) and continuously operated at 40,000 min ⁻¹ (30 minutes). . That is, the vertical state: the spindle tool mounting surface is turned downward (phase 90 °), and further rotated to the horizontal state (phase 180 °), and then passed through the vertical state (phase 90 °) to the horizontal state at the start (phase 0). A swing swinging cycle (about 20 seconds per cycle) was performed. Other test conditions are the same as those described above.

As shown in FIG. 11 , in the conventional product, the temperature rise before the swing is about 5 ° C. higher than that of the present invention product. In addition, in the conventional product, the outer ring temperature changed around 3 ° C. within about one hour after the start of the swing-turning cycle, but it was confirmed that the temperature of the inventive product hardly changed. The reason for this is considered to be that there is no unevenness in the discharge of internal lubricating oil during turning in the present invention product.

The device of the present invention has a temperature rise of about 5 ° C. lower than that of the conventional product, and further, there is little variation in temperature during the turning cycle operation. Therefore, it is possible to suppress the thermal displacement of the spindle and improve the processing accuracy. .
Further, since the lubricating oil is quickly discharged from the inside of the bearing, it is possible to reduce the risk of seizing due to abnormal heat generation from the stirring resistance due to the stagnation of the lubricating oil inside the bearing during high-speed operation.
As a result, machining by a spindle swing operation at a stable high-speed rotation becomes possible.

1 Portal machining center (multi-task machine tool)
20 spindle device 22 rotates shaft 30 rotor 32 stator 4 0 the outer ring spacer 42 ring spacer 60, 70, 2 70 front bearing 61, 71, 81, 2 71 the outer ring 71a, 71b, 81 a Haiyuana 76a, 76 b, 8 6 Atsumariyumizo 78, 88 oil supply hole 8 0 rear bearing (cylindrical roller bearing)
100, 101, 102 Oil drain passage 103 Negative pressure generator H Housing

Claims (3)

An inner ring having an inner ring raceway surface on the outer peripheral surface;
An outer ring having an outer ring raceway surface on the inner circumferential surface;
A plurality of balls arranged with a contact angle between the inner ring raceway surface and the outer ring raceway surface;
An outer ring guide retainer for retaining the plurality of balls at substantially equal intervals;
An angular contact ball bearing for a spindle device that is rotatably supported with respect to a housing and is lubricated by oil lubrication.
The internal space of the bearing is a sealed structure,
The outer ring, the oil supply hole that will be formed through the radially formed through the radial direction and the oil discharge hole is provided which opens in the inner peripheral surface of the counter bore,
The oil supply hole and the oil discharge hole open on an inner peripheral surface of the outer ring where the retainer is not guided,
The opening of the oil drainage hole has an inner end in the axial direction located between the outer ring raceway surface and an inner end surface in the axial direction of the pocket of the retainer, and an outer end in the axial direction of the retainer in the axial direction of the retainer. Arranged in the vicinity of the outer ring raceway surface so as to be located on the inner side in the axial direction from the outer end surface,
An angular contact ball bearing for a spindle device, wherein a negative pressure is applied to the oil drainage hole by a suction force from the outside of the bearing. 2. The angular contact ball for a spindle device according to claim 1, wherein the oil supply hole opens on an inner side in an axial direction than the retainer and on an inner peripheral surface of the outer ring where the retainer is not guided. bearing. Before SL refueling hole, with respect to the axial center position of the ball, on the opposite side of the contact point where the ball and the outer ring raceway surface are in contact, and opens into a position deviated in the axial direction from the axial center position ,
The oil drainage hole is opened in the inner peripheral surface of the outer ring that overlaps with the ball as seen from the radial direction,
The angular ball bearing for a spindle device according to claim 1 or 2, wherein the retainer is guided by an inner peripheral surface of the outer ring on the counter counterbore side.

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