JP2010052099A - Main spindle device and machine tool equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the whole axial dimension by shortening the span between front and rear bearings of a rotary shaft, and thus shortening the total length of the rotary shaft. <P>SOLUTION: In the main spindle device M, the rotary shaft 80 is freely rotatably supported by a housing H through the front and rear side bearings 25, 26, 36, and rotatably driven by a built-in motor 50. At least either a front side bearing housing 20 or a rear side bearing housing 30 has a thick-wall cylindrical part 21 in the diameter direction and a thin-wall cylindrical projection 22 axially projected from a stator side end part close to the inner diameter of the cylindrical part 21. The cylindrical projection 22 enters the inner circumference side of an end coil 53 of the stator 51, and outer rings 26a, 36a of the front or rear side bearings 26, 36 are fitted into the inner circumference surface of the cylindrical projection 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spindle device and a machine tool including the spindle device, and more particularly to a spindle device attached to a spindle head of a portal machining center and a general machine tool or a multi-tasking machine tool including the spindle device.

  Conventionally, as a multi-tasking machine tool that performs machining such as cutting and drilling by three-dimensional relative movement between a large workpiece and a tool, for example, a table to which a workpiece is attached is reciprocated linearly, and a spindle having a tool is set to X A portal machining center that controls in the direction of the axis, Y axis, and Z axis is used.

  In a portal machining center, a saddle is attached to a cross rail supported by two columns, a spindle head is attached to the end of a ram that moves vertically with respect to the saddle, and two spindle heads are supported. A motor built-in spindle device is pivotally attached to the arm via a bracket.

  FIG. 4 shows the structure of a spindle device described in Patent Document 1 as a motor built-in spindle device.

  In the figure, reference numeral 101 denotes an outer cylinder housing in which a rotating shaft 102 is inserted. A front bearing housing 110 is provided at the front part of the outer cylinder housing 101, and a rear bearing housing 120 is provided at the rear part of the outer cylinder housing 101, and the front part of the rotary shaft 102 is provided at the inner periphery of the front bearing housing 110. The front bearings 115 and 116 that rotatably support the rear shaft are disposed, and the rear bearings 125 and 126 that rotatably support the rear portion of the rotating shaft 102 are disposed on the inner periphery of the rear bearing housing 120.

In the space between the front bearing 116 and the rear bearing 125, the stator 151 and the rotor 152, which are elements of the built-in motor 150, are arranged in a state of being fixed to the outer cylinder housing 101 and the rotating shaft 102, respectively. .
Japanese Patent Publication No. 8-22481

  By the way, the convex part of the stator coil called the end coil 153 protrudes from the axial direction both ends of the stator 151. In the main shaft device of FIG. 4, the front bearing housing 110 is formed so as to avoid the end coil 153, the span between the front and rear bearings 116 and 125 is increased, and therefore the total length of the rotary shaft 102 is increased. There was a problem that the overall dimensions were increased.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to shorten the span between the front and rear bearings of the rotary shaft, thereby shortening the overall length of the rotary shaft and reducing the overall axial dimension. It is an object of the present invention to provide a spindle device and a machine tool provided with the same.

The above object of the present invention can be achieved by the following constitution.
(1) A rotating shaft is rotatably supported by a housing via front and rear bearings, and the rotating shaft is driven to rotate by a built-in motor.
The housing includes an outer cylinder housing to which a stator of the built-in motor is mounted, a front bearing housing in which an outer ring of the front bearing is fitted, and a rear part of the outer cylinder housing. A rear bearing housing in which an outer ring of the rear bearing is fitted,
At least one of the front bearing housing and the rear bearing housing has a thick cylindrical portion in the radial direction, and a thin cylindrical projection that protrudes in the axial direction from the stator side end near the inner diameter of the thick cylindrical portion. And
The cylindrical protrusion enters the inner peripheral side of the end coil of the stator, and the outer ring of the front or rear bearing is fitted in the inner peripheral surface of the cylindrical protrusion. Spindle device to do.
(2) The front side or rear side bearing is set such that the center of the rolling element is positioned on the stator side in the axial direction from the end of the end coil. Spindle device.
(3) A machine tool comprising the spindle device according to (1) or (2).
(4) The machine tool according to (3), wherein the spindle device is mounted on a tilt mechanism.

  According to the present invention, at least one of the front bearing housing and the rear bearing housing protrudes in the axial direction from the thick cylindrical portion in the radial direction and the stator side end near the inner diameter of the thick cylindrical portion. A thin cylindrical protrusion, and the cylindrical protrusion enters the inner peripheral side of the end coil of the stator, and the outer ring of the front or rear bearing is provided on the inner peripheral surface of the cylindrical protrusion. Fitted. Therefore, the span between the front and rear bearings can be shortened, contributing to the shortening of the overall length of the rotary shaft, thereby making it possible to reduce the axial dimension of the spindle device and reduce its weight. In addition, by reducing the span between the front and rear bearings of the rotating shaft, the natural frequency of the shaft can be increased, the maximum rotational speed can be increased, and the dynamic rigidity is increased to reduce vibration. It can also be suppressed. In addition, by reducing the inertia of the rotating part, an improvement in rapid acceleration and an energy saving effect by reducing power can be expected. When mounted on a tilt mechanism, the structure of the tilt mechanism can be made compact by making the spindle device compact and lightweight.

  In particular, the front or rear bearing is arranged so that the center of the rolling element is positioned on the stator side in the axial direction from the end of the end coil, so that the bearing is inserted into the inner peripheral side of the end coil. Thus, the span between the front and rear bearings can be further shortened.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a spindle apparatus and a portal machining center as a machine tool according to the present invention will be described in detail based on the drawings.

  As shown in FIG. 1, 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 at 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 also supports a ram 7 that can be moved up and down in the Z-axis direction. At the lower end of the ram 7, the spindle device M of the present invention can be rotationally indexed around the Y-axis and the Z-axis. A spindle head 8 to be held is mounted. A tilt mechanism (not shown) is provided in the two support arms 8 a of the spindle head 8, and the spindle device M is rotationally indexed around the Y axis via the bracket 9 by this tilt mechanism.

  As shown in FIG. 2, the spindle device M is of a motor built-in type, and includes an outer cylinder housing 10 fixed to the bracket 9, a rotary shaft 80 inserted into the outer cylinder housing 10, and an outer cylinder housing. 10, a front bearing housing 20 provided at the front portion of the outer cylinder housing 10, a rear bearing housing 30 provided at the rear portion of the outer cylinder housing 10, and a front side disposed between the front bearing housing 20 and the front portion of the rotary shaft 80. Bearings 25, 26, a rear bearing 36 disposed between the rear bearing housing 30 and the rear portion of the rotary shaft 80, and a built-in motor 50 disposed in a space between the front bearing 26 and the rear bearing 36. It is equipped with. The outer cylinder housing 10, the front bearing housing 20, and the rear bearing housing 30 constitute the housing H of the present invention. Thus, the rotary shaft 80 is rotatably supported by the housing H via the front bearings 25 and 26 and the rear bearing 36 and is driven to rotate by the built-in motor 50.

  As shown in FIGS. 2 and 3, the front bearings 25 and 26 are angular ball bearings having a plurality of balls 25 b and 26 b as rolling elements, respectively. These angular ball bearings 25 and 26 are interposed via spacers 27 and 28. The back is combined. The outer rings 25 a and 26 a of the front bearings 25 and 26 are fitted in the front bearing housing 20, and the inner rings 25 c and 26 c are fitted on the rotating shaft 80 and are inserted into a thread groove 80 a formed on the rotating shaft 80 in a bearing fixing nut 86. As a result, a preload is applied to the front bearings 25 and 26, and the inner rings 25c and 26c are fixed in the axial direction. The rear bearing 36 is a cylindrical roller bearing having a plurality of cylindrical rollers 36b as rolling elements. The outer ring 36a is fitted in the rear bearing housing 30, and the inner ring 36c is fitted on the rotary shaft 80. Has been.

  The built-in motor 50 includes a stator 51 fixed via a cooling cylinder 11 having a cooling groove 11 a on the inner periphery of the outer cylinder housing 10, and a rotor 52 shrink-fitted on a sleeve 81 provided on the outer periphery of the rotary shaft 80. The end coil 53 of the stator coil protrudes as a substantially annular convex portion at both axial ends of the stator 51. The sleeve 81 is fastened by shrinkage on the outer periphery of the rotating shaft 80.

  A draw bar 93 extending in the axial direction, a collet 90 provided on the tip end side of the draw bar 93, and a draw bar 93 and the rotary shaft 80 are provided on the inner diameter portion of the rotary shaft 80, and the collet 90 is drawn to the opposite tool side. A disc spring 94 is incorporated. In addition, an unclamping unit 91 for unclamping the tool holder by compressing the disc spring 94 incorporated in the inner diameter portion of the rotating shaft 80 is attached to the rear side of the rear bearing housing 30.

  Here, as shown in FIG. 2, the front bearing housing 20 and the rear bearing housing 30 are respectively fitted in the outer cylinder housing 10 and screwed to the outer cylinder housing 10. The front bearing housing 20 and the rear bearing housing 30 are thick in the radial direction in the thick cylindrical portions 21, 31 and axially from the stator side end closer to the inner diameter of the thick cylindrical portions 21, 31 to the stator 51 side. Projecting cylindrical projections 22 and 32 that are thinner than the cylindrical portion 21. These cylindrical projecting portions 22 and 32 enter the inner peripheral side of the end coil 53 projecting as a convex portion at the axial end portion of the stator 51, and the end coil 53 and the cylindrical projecting portions 22 and 32 are overhang in the axial direction. Wrapping. Further, the outer rings 26a and 36a of the bearings 26 and 36 near the stator are fitted into the inner peripheral surfaces of the cylindrical protrusions 22 and 32, and the stator side end surfaces of the outer rings 26a and 36a are fitted into the cylindrical protrusions 22 and 32. They are abutted against the inwardly stepped portions 22a and 32a formed in the direction and are positioned in the axial direction.

  Specifically, as shown in FIG. 3, the axial position of the front bearing 26 is set such that the center of the ball 26 b is positioned closer to the stator side in the axial direction than the end portion 53 a of the end coil 53. In particular, in the present embodiment, the axial position of the entire front bearing 26 is located on the stator side in the axial direction with respect to the end portion 53 a of the end coil 53. Such an arrangement relationship is the same for the rear bearing housing 30, the end coil 53, and the rear bearing 36.

  As described above, in the spindle device M having the configuration of the present embodiment, the cylindrical protruding portions 22 and 32 of the front bearing housing 20 and the rear bearing housing 30 enter the inner peripheral side of the end coil 53 of the stator 51. In addition, since the outer rings 26a, 36a of the front or rear bearings 26, 36 are internally fitted on the inner peripheral surfaces of the cylindrical protrusions 22, 32, the front and rear bearings 25, 26, 36 are placed closer to the stator 51. Can be placed in position. Accordingly, the span between the front and rear bearings 25, 26, and 36 can be shortened, which can contribute to shortening the overall length of the rotary shaft 80, thereby reducing the size and weight of the spindle device M in the axial direction. Can be planned. In particular, the front and rear bearings 26 and 36 are arranged such that the centers of the rolling elements 26 b and 36 b are positioned on the stator side in the axial direction with respect to the end portion 53 a of the end coil 53. The span between the front and rear bearings 25, 26, and 36 can be made shorter by inserting the front and rear bearings 26 and 36 on the side.

  Further, by reducing the span between the front and rear bearings 25, 26, and 36 of the rotating shaft 80, the natural frequency of the rotating shaft 80 can be increased, the maximum number of rotations can be increased, and the dynamic rigidity can be increased. It becomes possible to suppress vibration small by becoming high. In addition, by reducing the inertia of the rotating part, an improvement in rapid acceleration and an energy saving effect by reducing power can be expected. Further, when mounted on the tilt mechanism, the structure of the tilt mechanism can be made compact by making the spindle device M compact and lightweight.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In the embodiment described above, the front bearings are two rows of angular ball bearings, and the rear bearings are single row cylindrical roller bearings. However, the type and number of bearings are not limited to this, and are appropriately designed according to the state of use. can do.
In the above-described embodiment, the arrangement relationship of the present invention includes the arrangement relationship of the front bearing housing 20, the front bearing 26, and the end coil 53, and the arrangement relationship of the rear bearing housing 30, the rear bearing 36, and the end coil 53. Although applied to both, it may be applied to either one.

1 is a schematic view of a portal machining center to which a spindle device of the present invention is applied. It is sectional drawing of a main shaft apparatus. It is an expanded sectional view which shows the principal part of a main shaft apparatus. It is sectional drawing which shows the example of the conventional main axis | shaft apparatus.

Explanation of symbols

M Spindle device 10 Outer cylinder housing 20 Front bearing housing 21 Cylindrical part 22 Cylindrical protrusion 25, 26 Front bearing 30 Rear bearing housing 31 Cylindrical part 32 Cylindrical protrusion 36 Rear bearing 50 Built-in motor 51 Stator 52 Rotor 53 End Coil 80 Rotating shaft

Claims (4)

A rotating shaft is rotatably supported by a housing via front and rear bearings, and the rotating shaft is driven by a built-in motor to be driven by a spindle device,
The housing includes an outer cylinder housing to which a stator of the built-in motor is mounted, a front bearing housing in which an outer ring of the front bearing is fitted, and a rear part of the outer cylinder housing. A rear bearing housing in which an outer ring of the rear bearing is fitted,
At least one of the front bearing housing and the rear bearing housing has a thick cylindrical portion in the radial direction, and a thin cylindrical projection that protrudes in the axial direction from the stator side end near the inner diameter of the thick cylindrical portion. And
The cylindrical protrusion enters the inner peripheral side of the end coil of the stator, and the outer ring of the front or rear bearing is fitted in the inner peripheral surface of the cylindrical protrusion. Spindle device to do.   2. The spindle device according to claim 1, wherein the front or rear bearing is set such that a center of a rolling element thereof is positioned on a stator side in an axial direction from an end portion of the end coil.   A machine tool comprising the spindle device according to claim 1.   The machine tool according to claim 3, wherein the spindle device is mounted on a tilt mechanism.

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