JP5581885B2 - Spindle device and machine tool equipped with the same - Google Patents

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. 7 shows a structure of a spindle device 200 described in Patent Document 1 as a motor built-in spindle device.

  In FIG. 7, the spindle device 200 includes a motor housing 201, front and rear bearing housings 210 and 220 provided at the front and rear portions of the motor housing 201, and the housings 201, 210, and 220 are rotatable. And a rotating shaft 202 to be inserted. Front bearings 215 and 216 that rotatably support the front portion of the rotating shaft 202 are disposed on the inner periphery of the front bearing housing 210, and the rear portion of the rotating shaft 202 is rotatable on the inner periphery of the rear bearing housing 220. A rear bearing 225 for supporting the rear side is arranged. In the space between the front bearings 215 and 216 and the rear bearing 225, the stator 251 and the rotor 252 that are elements of the built-in motor 250 are arranged in a state of being fixed to the motor housing 201 and the rotating shaft 202, respectively. Yes.

  The inner ring of the front bearing 215 is fixed by shrink-fitting a sleeve 204 provided on the counter tool side through a plurality of spacers to a step portion 203 formed on the tool side with respect to the bearing 215 of the rotating shaft 202. ing. Further, the other front bearing 216 also shrink-fits a sleeve 206 provided on the side opposite to the tool via a plurality of spacers to a step portion 205 formed on the tool side with respect to the other bearing 216 of the rotating shaft 202. It is fixed by that. The inner ring of the rear bearing 225 is fixed by shrink fitting the sleeve 207 provided on the side opposite to the bearing 225 to the motor sleeve 240 that is shrink fitted on the rotating shaft 202 with a plurality of spacers interposed therebetween. Has been.

  As shown in FIG. 8, in the motor built-in spindle device 100 according to Patent Document 2, reference numeral 101 denotes an outer cylinder housing, in which a rotating shaft 102 is inserted. A front bearing housing 120 is provided at the front part of the outer cylinder housing 101, and a rear bearing housing 110 is provided at the rear part of the outer cylinder housing 101, and the front part of the rotating shaft 102 is provided at the inner periphery of the front bearing housing 120. A front bearing 125 that rotatably supports the rear shaft is disposed, and a rear bearing 115 that rotatably supports the rear portion of the rotary shaft 102 is disposed on the inner periphery of the rear bearing housing 120.

  In the space between the front bearing 125 and the rear bearing 115, 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. .

  The inner ring of the front bearing 125 is fixed to the rotating shaft 102 by fastening a nut 106 provided on the side opposite to the tool with respect to the bearing 125 via a plurality of spacers to a step portion 105 formed on the rotating shaft 102. Has been. Further, the inner ring of the rear bearing 115 is rotated by fastening a nut 104 provided on the side opposite to the tool with respect to the front bearing 125 via a plurality of spacers to a step portion 103 formed on the rotating shaft 102. It is fixed to the shaft 102.

Japanese Patent Laid-Open No. 2-15902 Japanese Patent Laid-Open No. 9-155562

  By the way, since the spindle device attached to the portal machining center is used while turning, it is desired to shorten the entire length of the spindle so as to reduce the turning radius.

  However, in the spindle devices 100 and 200 of Patent Documents 1 and 2, the spindle devices 100 and 200 are not used while turning, and no consideration is given to shortening the overall length of the spindle.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a spindle device capable of shortening the overall length of the spindle by shortening the axial length of the rotating shaft and a machine tool including the spindle device. It is to provide.

(1) A main shaft device in which a rotating shaft is rotatably supported by a housing via front and rear bearings, and the rotating shaft is rotationally driven by a built-in motor,
A step portion is formed on the tool side with respect to the front bearing of the rotating shaft, and a spacer and a bearing fixing nut are disposed between the front bearing and the rotor of the built-in motor,
By screwing and fastening the bearing fixing nut to the rotary shaft, the inner ring of the front bearing is fixed between the stepped portion and the bearing fixing nut via the spacer,
At least a part of the bearing fixing nut and the spacer has entered the inner peripheral side of the front end coil of the stator of the built-in motor ,
The bearing fixing nut has a tapped hole for balance correction on a tapered surface formed in a part of the outer periphery,
The housing is formed with a linear tool insertion portion along the axis of the tap hole,
The spindle device characterized in that the tool insertion portion is inclined with respect to the spindle device rotation axis so as not to interfere with the front end coil from the outside of the housing to the tap hole .
(2) A machine tool comprising the spindle device according to (1) and a tilt mechanism that rotates the spindle device.

  According to the present invention, a step portion is formed on the tool side with respect to the front bearing of the rotating shaft, and a spacer and a bearing fixing nut are arranged between the front bearing and the rotor of the built-in motor, By screwing and fastening the nut to the rotating shaft, the inner ring of the front bearing is fixed via a spacer between the stepped portion and the bearing fixing nut, and at least a part of the bearing fixing nut and the spacer are It enters the inner peripheral side of the front end coil of the stator of the built-in motor. As a result, there is no need to place a bearing fixing nut between the tool side tip and the front bearing, the axial length of the rotating shaft can be shortened, and the front bearing can be moved closer to the rotor. The span between the bearings is shortened, and the axial length of the rotating shaft can be shortened. Shortening the span between the front and rear bearings and the axial length of the rotating shaft can increase the natural value of the rotating shaft, increase the natural frequency of the shaft, and increase the maximum rotational speed. In addition, since the dynamic rigidity is increased, the vibration can be reduced. In addition, by reducing the span between the front and rear bearings of the rotating shaft, and by reducing the inertia of the rotating part, it is possible to expect an improvement in rapid acceleration and an energy saving effect by reducing power.

  Further, since a step portion is provided at the tool-side tip of the rotating shaft so as to be larger than the inner diameter of the front bearing, high rigidity can be secured at the tool-side tip of the rotating shaft. Further, due to the spacer interposed between the inner ring of the front bearing and the bearing fixing nut, the inner ring may be deformed due to partial tightening when the bearing fixing nut is screwed and fastened, or the inner ring is inclined with respect to the rotation shaft. It is prevented from being attached, and the rotation accuracy of the spindle device can be improved.

  The bearing fixing nut is formed with a tapped hole for balance correction, and the tool is inserted into the housing in a straight line from the outside of the housing to the tapped hole. Since the portion is formed, the balance can be easily corrected after the spindle is assembled.

  In addition, the spindle device of the present invention is mounted on a machine tool having a tilt mechanism, so that the turning radius of the spindle device is shortened, the turning structure is made compact, and the overall machine tool can be made compact and light. .

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 a principal part expanded sectional view of the main axis | shaft apparatus of FIG. It is a principal part expanded sectional view of the spindle apparatus which shows the 1st modification of a spindle apparatus. It is a principal part expanded sectional view of the main axis | shaft apparatus which shows the 2nd modification of a main axis | shaft apparatus. It is a principal part expanded sectional view of the rear side bearing periphery of a main shaft apparatus which shows the 3rd modification of a main shaft apparatus. It is sectional drawing which shows the example of the conventional main axis | shaft apparatus. It is sectional drawing which shows the example of the other conventional spindle apparatus.

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. Note that FIGS. 5 and 6 in this specification show a reference example as a premise.

  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 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 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 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. 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 outer cylinder housing 10, the front bearing housing 20, and the rear bearing housing 30 constitute the housing H of the present invention. In FIG. 2, the left side is referred to as the front side or the tool side, and the right side is referred to as the rear side or the counter tool side.

  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 front end coil 53a and the rear end coil 53b of the stator coil protrude as substantially annular convex portions at both axial ends of the stator 51. The sleeve 81 is fastened on the outer periphery of the rotating shaft 80 by shrink fitting. When removing the rotor 52 from the rotating shaft 80, the rotor 52 is pulled out to the opposite tool side of the rotating shaft 80 by supplying hydraulic pressure into the groove 81 a formed in the sleeve 81.

  Inside the rotary 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, a plate provided between the draw bar 93 and the rotary shaft 80, and pulling the collet 90 to the counter tool side A spring 94 is incorporated. Therefore, the tool holder 92 attached to the collet 90 is fitted to the tapered surface 80a formed on the inner peripheral surface of the rotary shaft 80 on the tool side by being pulled to the counter tool side. Further, an unclamping unit 91 that unclamps the tool holder 92 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.

  As shown in FIG. 3 in an enlarged manner, the front bearings 25 and 26 are angular ball bearings each having a plurality of balls 25b and 26b as rolling elements, and these angular ball bearings 25 and 26 are provided between the outer ring spacer 27 and the inner ring. The back surface is combined through the seat 28. On the outer peripheral surface on the tool side with respect to the front bearings 25 and 26 of the rotary shaft 80, an outward stepped portion 80b having a larger diameter than the outer peripheral surface on which the front bearings 25 and 26 are fitted is formed. The outer rings 25 a and 26 a of the front bearings 25 and 26 are abutted against the inward stepped portion 22 formed at the end on the side opposite to the tool of the front bearing housing 20, and are fitted into the front bearing housing 20. The front lid 40 is fixed in the axial direction by fastening and fixing. Further, the inner rings 25 c and 26 c of the front bearings 25 and 26 are fitted on the rotating shaft 80 by abutting against the outward stepped portion 80 b of the rotating shaft 80, and are formed on the rotating shaft 80 via the inner ring spacers 28 and 29. The front bearing fixing nut 86 is screwed and fastened into the threaded groove 80c so that the front bearings 25 and 26 are preloaded and fixed in the axial direction.

  When the bearing fixing nut 86 is screwed and fastened, it is offset between the thread groove 80c of the rotary shaft 80 and the female screw portion of the nut 86, so that the nut 86 is tilted with respect to the rotary shaft 80. It may become. The inner ring spacer 29 interposed between the inner ring 26c of the front bearing 26 and the bearing fixing nut 86 has a fitting clearance between the rotating shaft 80 of several μm to several tens of μm. It is possible to prevent the inner ring 26c from being deformed to be distorted by the uneven tightening at the time of screwing and fastening, or the inner ring 26c to be inclined and attached to the rotating shaft 80, which contributes to the rotation accuracy of the spindle device M.

  Further, as shown in FIG. 2, the rear bearing 36 is a cylindrical roller bearing provided with a plurality of cylindrical rollers 36b as rolling elements. The outer ring 36 a of the rear bearing 36 is abutted against an inwardly stepped portion 30 a formed in the rear bearing housing 30, is fitted in the rear bearing housing 30, and is fastened and fixed to the outer ring fixing member 37. Fixed in direction. Further, the inner ring 36 c is abutted on the outward stepped portion 80 d formed on the rotating shaft 80 via the spacer 38 and is externally fitted to the rotating shaft 80, and is formed on the rotating shaft 80 via the spacer 39. By tightening the rear bearing fixing nut 34 in the thread groove 80e, it is fixed in the axial direction.

  A recess 20 a is formed at the end of the front bearing housing 20 on the side opposite to the tool so that the end of the front aid coil 53 a of the stator 51 enters. Further, a part of the inner ring spacer 29 disposed between the front bearing 26 and the rotor 52 and the front bearing fixing nut 86 enter the inner peripheral side of the front end coil 53 a of the stator 51. In addition, an annular protrusion 80f having an L-shaped cross section for forming a non-contact labyrinth seal together with the front lid 40 is formed at the tool-side tip of the rotary shaft 80.

  Further, the rear bearing housing 30 in which the rear bearing 36 is fitted has a cylindrical portion 30 b formed on the tool side, and the cylindrical portion 30 b is formed on the inner peripheral side of the rear end coil 53 b of the stator 51. It has entered.

  With such an arrangement, the rotating shaft 80 can be shortened on the tool side and the counter tool side with respect to the motor 50, and the draw bar 93 can also be shortened.

  Furthermore, as shown in FIG. 3, the front bearing fixing nut 86 has a plurality of balance correction tap holes into which a balance correction weight (set screw) (not shown) can be screwed in order to correct the balance of the rotary shaft 80. 87 is formed. These tap holes 87 are opened in a tapered surface 86 a formed between the axial end surface facing the inner ring spacer 29 and the outer peripheral surface. Further, in the front bearing housing 20, a tool insertion hole 21 (tool) inclined linearly along the axis of the tap hole 87 from the outside of the housing 20 to the tap hole 87 so as not to interfere with the end coil 53 a of the stator 51. Insertion part) is formed. As a result, a balance correction tool (not shown) having a balance correction screw attached to the tip thereof from the tool insertion hole 21 can be inserted, and the balance correction weight can be attached to the tap hole 87.

  As described above, in the spindle device M having the configuration of the present embodiment, the outward stepped portion 80b is formed on the tool side with respect to the front bearings 25 and 26 of the rotary shaft 80, and the front bearings 25 and 26 and the built-in An inner ring spacer 29 and a bearing fixing nut 86 are disposed between the rotors 52 of the motor 50, and the inner rings 25 c of the front bearings 25 and 26 are fastened by screwing and fastening the front bearing fixing nut 86 to the rotary shaft 80. 26 c is fixed between the outward stepped portion 80 b and the front bearing fixing nut 86 via the inner ring spacer 29, and at least a part of the front bearing fixing nut 86 and the inner ring spacer 29 is fixed to the built-in motor 50. It enters the inner peripheral side of the front end coil 53a of the stator 51. Accordingly, the axial length of the rotary shaft 80 can be shortened, and the span between the front and rear bearings 25, 26, 36 is shortened by bringing the front bearings 25, 26 close to the rotor 52, so that the rotary shaft 80 The axial length of can be shortened. The span between the front and rear bearings 25, 26, and 36 and the shortening of the axial length of the rotating shaft 80 can increase the natural value of the rotating shaft 80, increase the natural frequency of the shaft 80, and the maximum. It is also possible to increase the number of rotations, and it is possible to suppress vibrations by increasing dynamic rigidity. Further, by reducing the span between the front and rear bearings 25, 26, and 36 of the rotary shaft 80, and by reducing the inertia of the rotating part, it is possible to expect an improvement in rapid acceleration and an energy saving effect by reducing power.

  In addition, since an outward stepped portion 80b is provided at the tool-side tip of the rotary shaft 80 so as to be larger than the inner diameter of the front bearings 25 and 26, high rigidity is ensured at the tool-side tip of the rotary shaft 80. Can do. Furthermore, due to the inner ring spacer 29 interposed between the inner ring 26c of the front bearing 26 and the bearing fixing nut 86, the inner ring 26c may be deformed by the tightening when the bearing fixing nut 86 is screwed and fastened, or the inner ring 26c. Is prevented from being inclined with respect to the rotation shaft 80, and the rotation accuracy of the spindle device M can be improved.

  The front bearing fixing nut 86 is formed with a tap hole 87 for balance correction, and the front bearing housing 20 is formed in a straight line from the outside of the housing 20 to the tap hole 87. Since the tool insertion part 21 into which the tool for insertion can be inserted is formed, balance correction after the spindle assembly can be easily performed.

  Further, the spindle device M of the present invention is mounted on a machine tool having a tilt mechanism, so that the turning radius of the spindle device M is shortened and the turning structure is made compact, and the entire machine tool is made compact and lightweight. Can also be planned.

  FIG. 4 is an enlarged cross-sectional view of the main part of the spindle device showing a first modification of the present invention. In this modification, the boundary portion between the non-tool side end surface of the front bearing housing 20 and the inner peripheral surface is bulged toward the tap hole 87 of the bearing fixing nut 86 so that the tool insertion portion 21 becomes longer. Thus, by designing the gap between the tap hole side opening of the tool insertion portion 21 and the tap hole 87 to be smaller than the length of the balance correction weight, the balance correction weight can be placed inside the spindle device at the time of balance correction. It is prevented that it is dropped.

  FIG. 5 is an enlarged cross-sectional view of the main part of the spindle device showing a second modification of the present invention. In this modification, the balance correcting tap hole 87 formed in the bearing fixing nut 86 is formed along the radial direction from the outer peripheral surface of the nut 86. A tool insertion portion into which a balance correcting tool can be inserted is formed by a radial hole 10a formed in the outer cylinder housing 10 and a notch portion 21a formed in the front bearing housing 20 extending in the radial direction. A straight line is formed from the outside to the tap hole 87.

  Thereby, since the coolant path 90 for cooling the front bearings 25 and 26 is formed on the outer diameter side of the front bearing housing 20, the spindle assembly is performed even when the tool insertion hole 21 cannot be formed obliquely. Later balance correction can be easily performed.

  In addition, as in this modification, at least a part of the bearing fixing nut 86 enters the inner peripheral side of the front end coil 53a of the stator 51 of the built-in motor 50. There is an effect.

  FIG. 6 is an enlarged cross-sectional view of a main part around the rear bearing of the main spindle device showing a third modification of the present invention. In this modification, the entire rear bearing 36 enters the inner peripheral side of the rear end coil 53 b of the stator 51 of the built-in motor 50. Thereby, the axial length of the rotating shaft 80 can be further shortened by bringing the rear bearing 36 closer to the rotor 52.

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 the bearings are not limited to this, and are appropriately designed according to the state of use. can do.

H housing M spindle device 10 outer cylinder housing 10a radial hole (tool insertion part)
20 Front bearing housing 21 Tool insertion hole (tool insertion part)
21a Notch (tool insertion part)
25, 26 Front bearing 29 Inner ring spacer (spacer)
30 Rear bearing housing 36 Rear bearing 50 Built-in motor 51 Stator 52 Rotor 53a Front end coil 53b Rear end coil 80 Rotating shaft 80b Outward stepped portion 86 Front bearing fixing nut 87 Tap hole

Claims (2)

A rotary shaft is rotatably supported by the housing via front and rear bearings, and the rotary shaft is driven to rotate by a built-in motor.
A step portion is formed on the tool side with respect to the front bearing of the rotating shaft, and a spacer and a bearing fixing nut are disposed between the front bearing and the rotor of the built-in motor,
By screwing and fastening the bearing fixing nut to the rotary shaft, the inner ring of the front bearing is fixed between the stepped portion and the bearing fixing nut via the spacer,
At least a part of the bearing fixing nut and the spacer has entered the inner peripheral side of the front end coil of the stator of the built-in motor ,
The bearing fixing nut has a tapped hole for balance correction on a tapered surface formed in a part of the outer periphery,
The housing is formed with a linear tool insertion portion along the axis of the tap hole,
The spindle device characterized in that the tool insertion portion is inclined with respect to the spindle device rotation axis so as not to interfere with the front end coil from the outside of the housing to the tap hole . A machine tool comprising: the spindle device according to claim 1; and a tilt mechanism for turning the spindle device.

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