JP5212142B2 - Angular contact ball bearings for spindle equipment - Google Patents

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. 14, 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 thereof is to provide an angular contact ball bearing for a spindle device that has good oil drainage and can suppress excessive lubricating oil and abnormal heat generation. It is in.

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 angular contact ball bearing for a spindle device that is rotatably supported with respect to a housing and is lubricated by oil lubrication.
It said outer ring, together with the oil discharge hole penetrating in the radial direction are formed, in the axial direction outside than the oil discharge hole, from the axial edge of the inner peripheral surface of the outer ring, the axial direction or the radial direction A notched drain groove is formed,
The oil drain groove and the oil drain hole are formed on the inner peripheral surface of the outer ring on the opposite side to the side on which lubricating oil is supplied to the ball,
The oil discharge groove and wherein the oil discharge hole, the spindle device for angular contact ball bearings, characterized in that the suction force from the bearing outside, the negative pressure acts.
(2) The angular contact ball bearing for a spindle device according to (1), wherein the oil drain groove and the oil drain hole are formed on an inner peripheral surface of the outer ring on a counter bore side .

According to the angular contact ball bearing for the spindle device of the present invention, a negative pressure is applied to the oil drain groove formed in the outer ring by the suction force from the outside of the bearing. Excess lubricating oil at the axial edge with the adjacent member can be quickly discharged through the oil drain groove. In particular, with tilt-type spindle devices, even if the attitude changes, the lubricating oil in the oil drain groove that should be discharged is prevented from returning to the raceway surface, suppressing excessive lubricating oil and abnormal heat generation. can do.

  Further, since the oil drain groove is notched in the axial direction or radial direction from the axial edge of the inner peripheral surface of the outer ring, excess lubrication accumulated at the axial edge with an adjacent member such as an outer ring spacer. Oil can be quickly discharged through the oil drain groove.

  Furthermore, since the oil drain groove is cut in the axial direction so as to communicate with the oil drain hole penetrating in the radial direction, it is necessary to provide an oil drain passage separately from the oil drain passage of the housing communicating with the oil drain hole. In addition, the processing work of the housing can be reduced.

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. (A) is a perspective view of the outer ring | wheel of the front side bearing of FIG. 5, (b) is the VI section enlarged view of (a). (A) is an expanded sectional view of the rear bearing of the spindle device, and (b) is an enlarged view of the main part when the oil drain groove of (a) is viewed from the radial direction. It is an expanded sectional view of the front side bearing which concerns on the spindle apparatus bearing of 2nd Embodiment. (A) is a perspective view of the outer ring | wheel of the front side bearing of FIG. 8, (b) is the IX section enlarged view of (a). 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 contact ball bearings each having a cage 64, 74, which are arranged in a rear 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 a roller guide cage 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 the outer ring spacer 40 with the nozzle and the outer ring spacer 51 with the flange are fixed by the front bearing outer ring presser 39 bolted to the outer cylinder 29. It is fixed to the outer cylinder 29 in the axial direction. 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.

  The outer ring 81 of the rear bearing 80 is fitted in the rear lid 34 and is fixed to the rear lid 34 via the outer ring spacer 52 by a rear bearing outer ring retainer 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.

  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 nozzles 40a (see FIG. 2), 40b (see FIG. 3) formed in the outer ring spacer 40, and rear bearing outer ring pressers. The nozzle 43a (see FIG. 4) formed in the nozzle 43 communicates with the lubricating oil sent by the lubricating device 93 from the side of each bearing 60, 70, 80 into the bearing space.

  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 FIGS. 5 and 6, in the front bearing 70, a plurality of balls 73 are formed on the inner peripheral surface of the outer ring 71 and the outer ring raceway surface 71 a 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 has at least one oil drain hole 71b that opens in the vicinity of the outer ring raceway surface 71a through which the ball 73 passes on the inner peripheral surface on the counter bore side and penetrates in the radial direction. A book (in this embodiment, one) is formed.

  An annular oil collecting groove 71c is formed on the inner peripheral surface of the outer ring 71 in the circumferential direction at an axial position where the oil drain hole 71b opens. The oil drain hole 71b is preferably opened in the vicinity of the outer ring raceway surface 71a of the outer ring 71, and an oil collecting groove 71c communicating with the oil drain hole 71b is a ball as viewed from the radial direction as shown in FIG. 73 is formed at a position overlapping with 73. 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 guided directly to the oil collecting groove 71c. However, the oil collecting groove 71c is not limited to the position overlapping the ball 73 when viewed from the radial direction.

  Further, the outer ring 71 is formed with at least one oil drain groove 71e (one in the present embodiment) in the circumferential direction, which is cut out in the radial direction from the axial edge 71d of the inner peripheral surface. And the hole for oil drainage is comprised by the axial direction end surface by the side of the collar 51a of the outer ring spacer 51 arrange | positioned adjacent to the outer ring | wheel 71, and the oil drain groove 71e.

  An annular groove 104 is formed on the inner peripheral surface of the outer cylinder 29 facing the outer ring 71 to communicate with both the outer peripheral side opening of the oil drain hole 71b and the oil drain groove 71e. For this reason, while being sucked by the negative pressure generator 103, the lubricating oil is collected by the oil collecting groove 172b and sent to the oil draining hole 71b, and then the oil draining passage through the annular groove 104 and the oil draining hole 29a. On the other hand, the lubricating oil that is discharged to the outside from the 101 and partitioned by the flanged outer ring spacer 51 and collected in the axial edge 71d of the outer ring 71 also passes through the annular groove 104 and the oil drain hole 29a from the oil drain groove 71e. Through the oil discharge passage 101 to the outside. 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.

  Further, as shown in FIG. 7, the rear bearing 80 also extends in the radial direction from the axial edge 81 d of the inner peripheral surface of the outer ring 81 on the side opposite to the side to which the lubricating oil is supplied, like the front bearings 60 and 70. At least one cut-out arcuate oil drain groove 81e (one in this embodiment) is formed in the circumferential direction.

  An annular circumferential groove 85 in which an oil drain groove 81e is opened is formed on the outer peripheral surface of the outer ring 81. The circumferential groove 85 is formed in the oil drain groove 81e and the oil drain passage 102 formed in the rear lid 34. The oil discharge hole 34a is communicated with.

  Further, an arc-shaped oil drain groove 52a that is radially cut out at a position facing the oil drain groove 81e is also formed on the axial end surface of the outer ring spacer 52 adjacent to the outer ring 81. As shown in FIG. 7B, the oil drain groove 52 a and the oil drain groove 81 e of the outer ring 81 constitute an oil drain hole having a smaller diameter than the oil drain hole 34 a.

  A circumferential groove 52b is also formed on the outer peripheral surface of the outer ring spacer 52 at an axial position where the oil drain groove 52a is opened. This circumferential groove 52b is also formed in the oil drain groove 52a and the rear lid 34. The oil discharge hole 34a of the oil discharge passage 102 thus made communicates.

  The cage 84 may be a roller guide system as in the present embodiment, or may be an outer ring guide system. Further, in the case of the outer ring guide method, the cage 84 may be formed so as to be guided only on one outer peripheral surface.

  Further, in the angular ball bearing, the lubricating oil supply direction may be from the front side rather than from the back side. Also in the cylindrical roller bearing, the lubricating oil supply direction may be from any axial direction. Furthermore, the oil supply of each bearing may be performed from an oil supply hole formed in the outer ring. Preferably, when the oil supply position is opposite to the oil discharge position with respect to the rolling elements, the lubricating oil can flow from the oil supply to the oil discharge and the oil supply to the lubrication point can be performed more reliably. Become.

  Accordingly, the lubricating oil in the oil drain holes 71b and the oil drain grooves 71e, 81e, and 52a, which lubricated the bearings 60, 70, and 80, is transferred to the annular grooves 104, the circumferential grooves 85 and 52b, and the oil drain passages 100 and 101. , 102 to the outside. At this time, a negative pressure acts on the oil drain hole 71b and the oil drain grooves 71e, 81e, 52a 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 hole 71b The lubricating oil in the oil drain grooves 71e, 81e, 52a is forcibly sucked. Also, of the inner peripheral surfaces of the outer rings 61, 71, 81, the lubricating oil adhering to the vicinity of the outer ring raceway surfaces 71 a, 81 c and the axial edges 71 d, 81 d is also discharged by the suction force of the negative pressure generator 103. The oil hole 71b and the oil drain grooves 71e, 81e, 52a are guided.

  Thereby, excess lubricating oil can be quickly discharged | emitted from the oil drain hole 71b provided in the vicinity of the outer ring raceway surface 71a of each bearing 60,70. Further, in each of the bearings 60, 70, 80, excess lubricating oil accumulated at the axial edge adjacent to the outer ring spacers 51, 52 can be quickly discharged through the oil drain grooves 71e, 81e, 52a. . In particular, in the tilt type spindle device 20 as in the present embodiment, even if the posture changes, the lubricating oil that should be discharged returns to the inside of the bearing, in particular, the oil drain hole 71b or the oil drain. Lubricating oil present in the grooves 71e, 81e, 52a is prevented from returning to the outer ring raceway surfaces 71a, 81c, and abnormal heat generation due to excessive lubricating oil and stirring resistance can be suppressed.

  Further, on the outer peripheral surfaces of the outer rings 61, 71, 81, an annular groove 104 or a circumferential groove that communicates the oil drain hole 71 b or the oil drain grooves 71 e, 81 e, 52 a and the oil drain passages 100, 101, 102 of the housing H. Since 85 and 52b are formed, the bearings 60, 70, and 80 can be assembled to the housing H without performing phase alignment with the oil drain passages 100, 101, and 102, and the assemblability of the spindle device 20 is improved. Is done.

  Further, since the oil collecting groove 71c is formed on the inner peripheral surface of the outer ring 71 at the axial position where the oil drain hole 71b opens, the bearing 70 adheres to the inner peripheral surface of the outer ring 71. Is collected in the oil collecting groove 71c, and the lubricating oil in the oil collecting groove 71c is quickly discharged into the oil drain hole 71b by the suction force of the negative pressure generating device 103. As a result, oil drainage can be further improved, and excessive lubricating oil and abnormal heat generation can be further suppressed.

  When the bearing 70 is rotating at a high speed, the internal air is also rotated by the viscous resistance during the revolution of the ball 73 and the rotation of the cage 74 and the inner ring 72, and a circumferential air flow is generated. Yes. Therefore, the oil adhering to the inner peripheral surface of the outer ring 71 also stays while moving in the circumferential direction along the inner peripheral surface. In particular, when the rotary shaft 22 is a vertical shaft, this oil retention is likely to occur because the gravity effect is small.

  When the spindle device 20 stops and the air flow stops, the remaining excess lubricating oil returns to the outer ring raceway surfaces 71a and 81c, and when the spindle device 20 is rotated again, or the spindle device 20 is tilted. When the posture changes, the accumulated oil returns to the outer ring raceways 71a and 81c and causes abnormal heat generation. However, suctioning this staying oil from the oil drain grooves 71e, 81e has an effect of eliminating the staying oil in the rotating state. Further, suction from the oil drain hole 71b communicating with the oil collecting groove 71c has an effect of preventing the return of the lubricating oil to the outer ring raceway surface 71a.

  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, the spindle device bearing according to the second embodiment of the present invention will be described in detail with reference to FIGS. In addition, in this embodiment, the structure of the angular ball bearing 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.

  As shown in FIGS. 8 and 9, in the angular ball bearing 170 of the present embodiment, the outer ring 171 is formed with an oil drain hole 71b and an annular oil collecting groove 71c, as in the first embodiment. Further, on the outer peripheral surface of the outer ring 71, instead of providing the annular groove 104 in the outer cylinder 29, an annular circumferential groove 175 in which an oil drain hole 71b is opened is formed. The circumferential groove 175 is formed as an oil drain hole. 71 b communicates with an oil drain hole 29 a of the oil drain passage 101 formed in the outer cylinder 29.

  Further, an oil drain groove 171e cut out in the axial direction from the axial edge 71d to the oil collecting groove 71c is formed on the inner peripheral surface of the outer ring 171 at a position corresponding to the oil drain hole 71b in the circumferential direction. Yes.

  Thus, excess lubricating oil adhering to the vicinity of the outer ring raceway surface 71a can be quickly discharged from the oil drain hole 71b provided in the vicinity of the outer ring raceway surface 71a of the bearing 70, and the axial direction adjacent to the outer ring spacer 51 Excess lubricating oil accumulated at the edge can also be quickly discharged from the oil drain hole 71b through the oil drain groove 171e.

  Furthermore, in the present embodiment, there is an effect that excess lubricating oil staying while rotating on the inner peripheral surface of the outer ring 171 is restricted by the oil drain groove 171e and effectively sucked.

Further, since the oil drain groove 171e is formed so as to communicate with the oil drain hole 71b, it is not necessary to provide an oil drain passage separately from the oil drain passage 101 of the housing H communicating with the oil drain hole 71b. The machining work can be reduced.
Other configurations and operations are the same as those in the first embodiment. In addition, since the front side bearing 60 is also the same structure as the front side bearing 170 arrange | positioned by the front side bearing 170 and a back surface combination, the said effect can be show | played.

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.

  Further, as in the machine tool spindle device 20a shown in FIG. 10, the oil drain holes of the bearings 60, 70, 80 communicate with a single oil drain passage 110 formed in the housing H. 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. 22, the nozzles 40 a and 40 b of the front bearings 60 and 70 having different phases and the nozzle 43 a 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. 7) 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: 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. 11 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. 11, in the product of the present invention, the temperature increase value of the outer ring of the bearing is low as the rotational speed rises compared to the conventional product, and in particular, at a high speed 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. 12, 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. 13, 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 Rotating shaft 30 Rotor 32 Stator 51, 52 Outer ring spacer 60, 70, 170 Front bearing (angular ball bearing)
61, 71, 81, 171 Outer ring 71b Oil drain hole 71c Oil collecting groove 71e, 81e, 171e Oil drain groove 80 Rear bearing (cylindrical roller bearing)
100, 101, 102 Oil drain passage 103 Negative pressure generator H Housing

Claims (2)

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 angular contact ball bearing for a spindle device that is rotatably supported with respect to a housing and is lubricated by oil lubrication.
It said outer ring, together with the oil discharge hole penetrating in the radial direction are formed, in the axial direction outside than the oil discharge hole, from the axial edge of the inner peripheral surface of the outer ring, the axial direction or the radial direction A notched drain groove is formed,
The oil drain groove and the oil drain hole are formed on the inner peripheral surface of the outer ring on the opposite side to the side on which lubricating oil is supplied to the ball,
The oil discharge groove and wherein the oil discharge hole, the spindle device for angular contact ball bearings, characterized in that the suction force from the bearing outside, the negative pressure acts. 2. The angular contact ball bearing for a spindle device according to claim 1, wherein the oil drain groove and the oil drain hole are formed on an inner peripheral surface of the outer ring on a counter bore side .

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