JP2010052098A - 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 partially 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. 5 shows a structure of a spindle device described in Patent Document 1 as a motor built-in type 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. 5, the front bearing housing 110 is formed in such a manner as to avoid the end coil 153, and the span between the front and rear bearings 116 and 125 becomes large, so that the total length of the rotary shaft 102 becomes long, 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 protruding portion that protrudes in the axial direction from a stator side end near the inner diameter of the cylindrical portion, Have
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 partially fitted on the inner peripheral surface of the cylindrical protrusion. Spindle device characterized by
(2) The spindle according to (1), wherein the front or rear bearing is arranged such that a center of a rolling element thereof overlaps with the thick cylindrical portion when viewed from a radial direction. apparatus.
(3) The front or rear bearing is an angular ball bearing having a ball as the rolling element,
The center of the ball overlaps with the cylindrical protrusion when viewed from the radial direction, or
The extension line of the contact angle of the angular ball bearing passes through the thick cylindrical portion without intersecting the stator side end surface of the cylindrical portion and the outer peripheral surface of the cylindrical protruding portion ( The spindle apparatus as described in 1).
(4) A machine tool comprising the spindle device according to any one of (1) to (3).
(5) The machine tool according to (4), 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 has a thick cylindrical portion in the radial direction, and a thin cylinder that protrudes in the axial direction from the stator side end near the inner diameter of the cylindrical portion. A cylindrical protrusion that enters the inner peripheral side of the end coil of the stator, and the outer ring of the front or rear bearing is partially inside 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.

  Further, the front or rear bearing is arranged so that the center of the rolling element overlaps the thick cylindrical portion when viewed from the radial direction, thereby minimizing the decrease in rigidity supporting the rotating shaft. be able to.

  Further, the front or rear bearing is an angular ball bearing having a ball as a rolling element, the center of the ball overlaps with the cylindrical protrusion when viewed from the radial direction, and is an extension line of the contact angle of the angular ball bearing. By passing through the thick cylindrical portion without intersecting the stator side end surface of the cylindrical portion and the outer peripheral surface of the cylindrical protruding portion, it is possible to minimize a decrease in rigidity supporting the rotating shaft.

  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 partially fitted into the inner peripheral surfaces of the cylindrical projecting portions 22 and 32, that is, the inner peripheral surfaces of the thick cylindrical portions 21 and 32, respectively. It is internally fitted so as to straddle the inner peripheral surfaces of the cylindrical protrusions 22 and 32. Further, the stator-side end surfaces of the outer rings 26a and 36a are abutted against inwardly stepped portions 22a and 32a formed inwardly on the cylindrical projecting portions 22 and 32, and are positioned in the axial direction.

  That is, as shown in FIG. 3, the cylindrical protrusion 22 of the front bearing housing 20 overlaps the end coil 53 by a dimension A in the axial direction. The axial position of the front bearing 26 is such that the center of the ball 26b overlaps the thick cylindrical portion 21 when viewed from the radial direction, that is, from the stator side end surface 21a of the thick cylindrical portion 21. The dimension B is set to be located on the side opposite to the stator 51. 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 protrusions 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 partially fitted on the inner peripheral surfaces of the cylindrical projecting portions 22, 32, the front and rear bearings 25, 26, 36 are more fitted to the stator. It can be arranged at a position closer to 51. 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.

  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.

  Further, the axial position of the front bearing 26 is arranged so that the center of the ball 26b overlaps the thick cylindrical portion 21 when viewed from the radial direction, thereby minimizing the reduction in rigidity for supporting the rotary shaft 80. To the limit.

  When the front bearing 26 is an angular ball bearing as in the present embodiment, the axial position of the front bearing 26 is viewed from the radial direction when the center of the ball 26b is viewed from the radial direction as in the modification shown in FIG. The cylindrical protrusion 22 overlaps or the extension line L of the contact angle of the angular ball bearing does not intersect the stator-side end surface 21a of the thick cylindrical portion 21 and the outer peripheral surface 22b of the cylindrical protrusion 22 and is thick. It passes through the cylindrical portion 21 of meat (both conditions are satisfied in this embodiment). That is, a distance C is ensured between the boundary position between the stator-side end surface 21a of the thick cylindrical portion 21 and the outer peripheral surface 22b of the cylindrical protrusion 22 and the extension line L on the side opposite to the stator from the boundary position. ing. Accordingly, it is possible to arrange the front bearings 25 and 26 closer to the stator 51 while minimizing the decrease in rigidity that supports the rotating shaft 80.

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 an expanded sectional view which shows the principal part of the modification 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 (5)

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 protruding portion that protrudes in the axial direction from a stator side end near the inner diameter of the cylindrical portion, Have
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 partially fitted on the inner peripheral surface of the cylindrical protrusion. Spindle device characterized by   2. The spindle device according to claim 1, wherein the front or rear bearing is disposed such that a center of a rolling element thereof overlaps with the thick cylindrical portion when viewed from a radial direction. The front side or rear side bearing is an angular ball bearing having balls as the rolling elements,
The center of the ball overlaps with the cylindrical protrusion when viewed from the radial direction, or
The extension line of the contact angle of the angular ball bearing passes through the thick cylindrical portion without intersecting the stator side end surface of the cylindrical portion and the outer peripheral surface of the cylindrical protruding portion. Item 2. The spindle device according to item 1.   A machine tool comprising the spindle device according to claim 1.   The machine tool according to claim 4, wherein the spindle device is mounted on a tilt mechanism.

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