JP2009185979A - Angular contact ball bearings for spindle equipment - Google Patents

Abstract

The present invention provides an angular contact ball bearing for a spindle device that has good oil drainage and can suppress excessive lubricating oil with respect to the bearing and abnormal heat generation of the bearing.
An angular contact ball bearing 70 for a spindle device includes an inner ring 72 having an inner ring raceway surface 72a on an outer peripheral surface, an outer ring 71 having an outer ring raceway surface 71a on an inner peripheral surface, an inner ring raceway surface 72a and an outer ring raceway surface 71a. There are a plurality of balls 73 arranged with a contact angle between them, and an outer ring spacer 75 arranged adjacent to the outer ring 71 around the inner ring 72. In the outer ring spacer 75, an oil drain hole 75a communicating with the internal space of the bearing 70 is formed in the radial direction. A negative pressure is applied to the oil drain hole 75 a by the suction force of the negative pressure generator 103.
[Selection] Figure 5

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. 10, 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 is achieved by the following configurations.
(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 spacer disposed around the inner ring and adjacent to the outer ring;
An angular contact ball bearing for a spindle device that is rotatably supported with respect to a housing and is lubricated by oil lubrication.
In the outer ring spacer, an oil drainage portion communicating with the internal space of the bearing is formed in the radial direction,
An angular contact ball bearing for a spindle device, wherein a negative pressure is applied to the oil drainage portion by a suction force from the outside of the bearing.

  According to the angular contact ball bearing for the spindle device of the present invention, a negative pressure is applied to the oil drainage portion formed in the outer ring spacer by the suction force from the outside of the bearing, so that excess lubricating oil inside the bearing is drained. It can be quickly discharged through the oil hole. 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.

  In addition, since the oil drainage part formed over the radial direction that communicates with the internal space of the bearing is formed in the outer ring spacer, it is not necessary to process the oil drainage part into the outer ring, and the workability is good. Become.

(First embodiment)
Hereinafter, an angular contact ball bearing for a spindle device 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.

  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 having outer ring spacers 65 and 75 arranged adjacent to the outer ring 71 around the inner ring 72 and 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 an outer ring guide cage 84 that holds the cylindrical roller 83 at substantially equal intervals. .

  The outer rings 61 and 71 of the front bearings 60 and 70 are fitted in the outer cylinder 29 and are attached to the outer cylinder 29 via the outer ring spacer 40 with a nozzle by a front bearing outer ring presser 39 bolted to the outer cylinder 29. It is fixed 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.

  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.

  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 for feeding the lubricant oil is provided to one end side of these paths 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 an enlarged view in FIG. 5, 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. Further, the outer ring 71 has an inner ring so that its axial end surface is positioned in the vicinity of the outer ring raceway surface 71a opposite to the contact point P1 between the ball 73 and the outer ring raceway surface 71a with respect to the axial center position O of the ball 73. The axial width is shorter than 72. The outer ring spacer 75 adjacent to the outer ring 71 includes a plurality of oil drain holes 75a that are oil drain portions that communicate the internal space of the bearing 70 and the oil drain passage 101 of the outer cylinder 29 at substantially equal intervals in the circumferential direction. Each book is formed. These oil drain holes 75a penetrate the outer ring spacer 75 in the radial direction and incline away from the outer ring 71 as going outward in the radial direction.

  An annular circumferential groove 75b in which an oil drain hole 75a is opened is formed on the outer circumferential surface of the outer ring spacer 75, and an axis in which the oil drain hole 75a is opened on the inner circumferential surface of the outer ring spacer 75. An annular oil collecting groove 75c is formed in the circumferential position in the circumferential direction. The oil drain hole 75a preferably opens in the vicinity of the outer ring raceway surface 71a of the outer ring 71. As shown in FIG. 5, at least the oil collecting groove 75c communicating with the oil drain hole 75a is seen from the radial direction. It is formed at a position overlapping with the ball 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 75c. Further, in the present embodiment, the sum of the axial widths of the outer ring 71 and the outer ring spacer 75 is formed so as to substantially match the axial width of the inner ring 72. Furthermore, since 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, the description thereof is omitted.

  As shown in FIG. 4, the rear bearing 80 has an oil drain hole 81 a that penetrates in the radial direction in the vicinity of the outer ring raceway surface 81 c through which the cylindrical roller 83 passes on the inner circumferential surfaces on both axial sides of the outer ring 81. , 81b are formed in a plurality at regular intervals in the circumferential direction. The outer circumferential surface of the outer ring 81 is formed with annular circumferential grooves 85a and 85b in which the oil drain holes 81a and 81b are opened. The circumferential grooves 85a and 85b are formed of the oil drain holes 81a and 85b, respectively. 81 b communicates with the oil drainage passage 102 formed in the rear lid 34.

  Accordingly, the lubricating oil in the oil drain holes 75a, 81a, 81b, which lubricated the bearings 60, 70, 80, passes through the circumferential grooves 75b, 85a, 85b and the oil drain passages 100, 101, 102, respectively. It is discharged outside. At this time, the suction force from the outside of the bearing, that is, the suction force of the negative pressure generator 103, negative pressure acts in the oil drain holes 75a, 81a, 81b, and the oil drain holes 75a, 81a, 81b have a negative pressure. Lubricating oil 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 is also guided to the oil drain holes 75a, 81a, 81b by the suction force of the negative pressure generator 103.

  As described above, the angular contact ball bearing 70 for the spindle device of the present embodiment has the outer ring spacer 75 in which the oil drain hole 75a communicating with the internal space of the bearing 70 is formed over the radial direction. As a result, a negative pressure is applied to the oil drain hole 75a by the suction force of the negative pressure generator 103, and the lubricating oil inside the bearing is sucked through the oil drain hole 75a formed in the outer ring spacer 75. Therefore, excess lubricating oil inside the bearing can be quickly discharged. In particular, in the tilt type spindle device 20, even if the posture changes, the lubricating oil in the drain hole 75a that should be discharged is prevented from returning to the raceway surface, and excessive lubricating oil or abnormal heat generation is prevented. Can be suppressed.

  Further, an oil drain hole 75a formed in the outer ring spacer 75 that communicates the internal space of the angular ball bearing 70 and the oil drain passage 101 of the housing H is formed in the outer ring spacer 75, so the oil drain hole 75a. There is no need to process the outer ring 71 into a structure with good workability.

  Further, a circumferential groove 75b that connects the oil drain hole 75a and the oil drain passage 101 of the housing H is formed on the outer peripheral surface of the outer ring spacer 75 of the angular ball bearing 70. The bearing 70 can be assembled to the housing H without performing phase alignment, and the assemblability of the spindle device 20 is improved.

  Further, since the oil collecting groove 75c is formed in the inner circumferential surface of the outer ring spacer 75 at the axial position where the oil drain hole 75a is opened in the circumferential direction, the oil collecting groove 75c adheres to the inner circumferential surface of the outer ring 71. The lubricating oil that has lubricated the bearing 70 is collected in the oil collecting groove 75c, and the lubricating oil in the oil collecting groove 75c is quickly discharged to the oil drain hole 75a 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 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 and the inner peripheral surface of the outer ring spacer 75 also moves 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 is the oil collecting groove 75c, the oil is easily collected in the oil collecting groove 75c, and the oil drainage is improved. Therefore, the oil collecting groove 75c is more preferably arcuate than square.

  In addition, since the front bearing 60 on the tool side also has the same configuration as the angular ball bearing 70 on the counter tool side, the above effects can be achieved. Also in the case of the cylindrical roller bearing 80, excess lubricating oil can be quickly discharged from the oil drain holes 81a and 81b provided near the outer ring raceway surface 81c by the suction force of the negative pressure generator 103. .

  Further, as shown in FIG. 6, an annular groove 104 may be formed on the inner peripheral surface of the outer cylinder 29 facing the outer peripheral side opening of the oil drain hole 75a instead of the circumferential groove 75b. In this case, the annular groove 104 is formed so as to communicate with the oil drain hole of the oil drain passage 101. For this reason, while being sucked by the negative pressure generating device 103, the lubricating oil is collected by the oil collecting groove 75c, sent to the oil draining hole 75a, and then from the oil draining passage 101 to the outside through the annular groove 104. Discharged.

  Further, in the present embodiment, the oil drain holes 75a of the angular ball bearing 70 and the oil drain holes 81a and 81b of the cylindrical roller bearing 80 are respectively formed in the circumferential direction, but at least one is formed in the circumferential direction. It only has to be done.

(Second Embodiment)
Next, an angular contact ball bearing for a spindle device according to a second embodiment of the present invention will be described in detail with reference to FIGS. In addition, about the part equivalent to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

  As shown in FIGS. 7 and 8, in the angular ball bearing 170 of the present embodiment, the outer ring spacer 175 is adjacent to the outer ring 71 around the inner ring 72 as in the outer ring spacer 75 of the first embodiment. Be placed. The outer ring spacer 175 has at least one oil drain groove 175a in the circumferential direction on the axial end face adjacent to the axial end face of the outer ring 71 in the circumferential direction (one in the present embodiment). It is formed over.

  An annular circumferential groove 175b in which an oil drain groove 175a is opened is formed on the outer circumferential surface of the outer ring spacer 175, and an axis in which the oil drain groove 175a is opened on the inner circumferential surface of the outer ring spacer 175. An annular oil collecting groove 175c is formed in the circumferential position in the circumferential direction. As a result, the oil drain groove 175a is positioned so as to overlap the ball 73 when viewed from the radial direction, and opens in the vicinity of the outer ring raceway surface 71a of the outer ring 71. As a result, there is an advantage that after the rolling contact portion is lubricated, the oil adhering to the ball 73 is shaken off by the centrifugal force and then directly guided to the oil drain groove 175a. The front bearing 60 has the same configuration as that of the front bearing 170 disposed in combination with the front bearing 170 and the back surface, and the description thereof is omitted.

Therefore, according to the angular contact ball bearing 170 for the spindle device of the present embodiment, the oil drain groove 175a, the circumferential groove 175b, and the oil collecting groove 175c are formed on the axial end surface adjacent to the outer ring 71. The oil drainage portion communicating with the H oil drainage passage 101 can be more easily processed.
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 the present embodiment, the sum of the axial widths of the outer ring 71 and the outer ring spacers 75 and 175 is formed so as to substantially match the axial width of the inner ring 72, but the present invention is not limited to this. For example, the axial end surfaces of the outer ring spacers 75 and 175 may extend from the axial end surface of the inner ring 72 in the axial direction.
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. 9, 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. 9, 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.

1 is a schematic view of a portal machining center to which a spindle device including a bearing of the present invention is applied. FIG. 3 is a cross-sectional view showing an oil supply passage and an oil discharge passage of one front bearing in the spindle device of the first embodiment. 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 showing the modification of the front side bearing of this embodiment. It is an expanded sectional view of the front side bearing which concerns on the main shaft apparatus of 2nd Embodiment. (A) is a perspective view of the outer ring spacer of the front bearing of the second embodiment, and (b) is an enlarged view of the VIII part 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. It is sectional drawing in the conventional main axis | shaft apparatus.

Explanation of symbols

1 Portal machining center (multi-task machine tool)
20 Spindle device 22 Rotating shaft 30 Rotor 32 Stator 60, 70, 170 Front bearing (angular ball bearing)
61, 71, 81 Outer ring 75, 175 Outer ring spacer 75a, 81a, 81b, 175a Oil drain hole 80 Rear bearing (cylindrical roller bearing)
100, 101, 102 Oil drain passage 103 Negative pressure generator 75b, 175b Circumferential groove 75c, 175c Oil collecting groove H Housing

Claims (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 spacer disposed around the inner ring and adjacent to the outer ring;
An angular contact ball bearing for a spindle device that is rotatably supported with respect to a housing and is lubricated by oil lubrication.
In the outer ring spacer, an oil drainage portion communicating with the inner space of the bearing is formed in the radial direction,
An angular contact ball bearing for a spindle device, wherein a negative pressure is applied to the oil drainage portion by a suction force from the outside of the bearing.

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