JP2011148015A - Main spindle device and machine tool with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a main spindle device capable of reducing an entire length of a main spindle by shortening a length in an axial direction of a rotating shaft, obtaining a good maintainability when extracting a front side bearing, being rotated at a high speed and reducing vibration during high speed, and also to provide a machine tool with the same. <P>SOLUTION: In the main spindle device M, a shoulder part 81a is formed between the front side bearing 26 and a rotor 52 of a built-in motor 50 on the rotating shaft 80, and an inner ring spacer 29 is arranged between the shoulder part 81a of the rotating shaft 80 and the inner ring 26c of the front side bearing 26. The shoulder part 81a of the rotating shaft 80 is positioned closer to a stator than the end surface 53a1 at the tool side of the end coil 53a of the stator 51 of the built-in motor 50. A space part s to which the end surface of the inner ring spacer 29 faces is formed around an end surface to which the shoulder part 81a opposes to the inner ring spacer 29. <P>COPYRIGHT: (C)2011,JPO&amp;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. 7 shows a structure of a spindle device 100 described in Patent Document 1 as a motor built-in spindle device.

  A spindle device 100 shown in FIG. 7 includes a rotating shaft 102 to which the rotor 101 is fixed, and a housing 104 to which the stator 103 is fixed. The passage 104 of the cooling fluid parallel to the rotating shaft 102 is formed inside the peripheral wall of the housing 104, thereby eliminating the need for a stator sleeve having a cooling jacket and reducing the size of the apparatus. In the main shaft device 100, the front bearing 106 and the rear bearing 107 that support the rotating shaft 102 are disposed inside the end coil 103 a of the stator 103.

Japanese Patent No. 2785691

  Incidentally, since the spindle device attached to the machining center is used while turning, it is desired to shorten the entire length of the spindle so as to reduce the turning radius. Further, in the spindle device, it is desired to improve the maintainability of the front bearing which is a replacement part. At the same time, in the spindle device, high-speed rotation and vibration reduction at high speed are also desired.

  However, in the spindle device of Patent Document 1, the front bearing 106 and the rear bearing 107 are arranged inside the end coil 103a of the stator 103, so that the span between the bearings can be shortened, but the spindle overall length is shortened. This is not described, and specific assembly of the front bearing 106 and the rear bearing 107 and maintenance of the front bearing 106 are not described.

  The present invention has been made in view of the above-described circumstances, and the object thereof is to shorten the axial length of the rotating shaft to shorten the entire length of the main shaft, and to maintain good maintenance when pulling out the front bearing. Thus, it is possible to provide a spindle device that can rotate at high speed and can reduce vibration at high speed, and a machine tool including the spindle device.

The above object of the present invention can be achieved by the following constitution.
(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,
The rotary shaft has a shoulder formed between the front bearing and the rotor of the built-in motor, and an inner ring spacer is disposed between the shoulder of the rotary shaft and the inner ring of the front bearing,
The shoulder of the rotating shaft is located closer to the stator than the tool side end surface of the end coil of the built-in motor stator,
A spindle device characterized in that a space portion is formed around the end surface where the shoulder portion and the inner ring spacer come into contact with each other so as to face the end surface of the inner ring spacer.
(2) The spindle device according to (1), wherein an outer diameter of the inner ring spacer is larger than an outer diameter of the shoulder portion.
(3) A balance correction tap hole is obliquely formed in the shoulder of the rotating shaft, and the housing is formed in a straight line from the outside of the housing to the tap hole. The spindle apparatus according to (1) or (2), wherein a tool insertion portion into which a tool can be inserted is formed.
(4) The rotating shaft has a flange portion having an outer diameter dimension substantially equal to the outer diameter of the rotor between the shoulder portion and the tool side end surface of the rotor.
The space portion is formed by at least one of the shoulder portion having a smaller diameter than the flange portion and a small diameter portion formed on a tool side end surface of the inner ring spacer (2) or (3). Spindle device described in 1.
(5) A machine tool comprising: the spindle device according to any one of (1) to (4); and a tilt mechanism that rotates the spindle device.

According to the present invention, the rotary shaft has a shoulder formed between the front bearing and the rotor of the built-in motor, and the inner ring spacer is disposed between the shoulder of the rotary shaft and the inner ring of the front bearing. And since the shoulder part of the rotating shaft is located closer to the stator than the end surface of the end coil of the built-in motor stator, the axial length of the rotating shaft can be shortened to shorten the entire length of the main shaft. it can. In addition, a space where the end face of the inner ring spacer faces is formed around the end face where the shoulder part and the inner ring spacer abut, so when pulling out the front bearing, it is connected to the inner ring of the front bearing via the inner ring spacer. An axial force can be applied, and good maintainability can be obtained.
In addition, the eigenvalue of the rotating shaft is increased by shortening the rotating shaft, and the mass of the rotating body including the rotating shaft is reduced and the eigenvalue is further increased by forming the space portion. Thereby, the rotating shaft can be rotated at a higher speed, and an effect of reducing vibration at high speed can be expected.
For example, the space is provided by making the outer diameter of the inner ring spacer larger than the outer diameter of the shoulder.

  In addition, a tapping hole for correcting the balance is formed obliquely on the shoulder of the rotating shaft, and a tool for correcting the balance, which is formed in a straight line from the outside of the housing to the tapped hole, can be inserted into the housing. Since a simple tool insertion part is formed, the balance can be easily corrected after the spindle is assembled.

  Furthermore, since the rotating shaft has a flange portion having an outer diameter approximately equal to the outer diameter of the rotor between the shoulder portion and the tool side end surface of the rotor, the bending rigidity of the rotating shaft can be increased and the eigenvalue can be increased. Can do. In addition, since the space portion is formed by at least one of a shoulder portion having a smaller diameter than the flange portion and a small diameter portion formed on the tool side end surface of the inner ring spacer, the inner space between the inner ring and the outer ring portion is removed when the front bearing is pulled out. A tool for pushing the seat in the axial direction can be inserted.

  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 sectional drawing which shows the case where the counterbore side end surface of an outer ring | wheel is pressed. 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 sectional drawing which shows the example of the conventional main axis | shaft 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.

  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. Built-in motors disposed in the spaces between the bearings 25 and 26, the rear bearings 36 and 37 disposed between the rear bearing housing 30 and the rear portion of the rotary shaft 80, and the front bearing 26 and the rear bearing 36. 50.

  The rotary shaft 80 is rotatably supported by the housing H via the front bearings 25 and 26 and the rear bearings 36 and 37 and is rotationally driven 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 the cooling cylinder 11 having a cooling groove 11a on the inner periphery of the outer cylinder housing 10, and a rotor 52 shrink-fitted on the outer periphery of the rotary shaft 80. End coils 53a and 53b of the stator coil protrude from the both ends in the axial direction of the stator 51 as substantially annular convex portions.

  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 an enlarged view in FIG. 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, and these angular ball bearings 25 and 26 are interposed via spacers 27 and 28. The back is combined. On the outer peripheral surface of the rotary shaft 80 opposite to the front bearings 25 and 26, a flange portion 81 having a diameter larger than that of the outer peripheral surface on which the front bearings 25 and 26 are externally fitted is close to the tool side end surface of the rotor 52. 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 via the outer ring spacer 27, so The front lid 40 is fastened and fixed to the front bearing housing 20 and fixed in the axial direction. 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 shoulder portions 81 a of the flange portion 81 via the inner ring spacers 24, 28 and 29, and the tip of the rotating shaft 80. The front bearing fixing nut 86 is screwed and fastened into the thread groove 80c formed close to the front groove 25, so that the front bearings 25 and 26 are preloaded and fixed in the axial direction. The inner ring spacer 24 constitutes a non-contact labyrinth seal together with the front lid 40.

  Further, as shown in FIG. 2, the rear bearings 36 and 37 are angular ball bearings having a plurality of balls 36 b and 37 b as rolling elements, and are combined on the back via spacers 38 and 39. The outer rings 36a and 37a of the rear bearings 36 and 37 are abutted against an inward stepped portion 30a formed in the rear bearing housing 30 via an outer ring spacer 38, and are fitted into the rear bearing housing 30. The outer ring fixing member 40 is fixed in the axial direction by fastening and fixing. Further, the inner rings 36 c and 37 c are fitted on the rotating shaft 80 by abutting on the outward stepped portion 80 d formed on the rotating shaft 80 via the inner ring spacers 39, 41 and 42, and are formed on the rotating shaft 80. By tightening the rear bearing fixing nut 34 in the thread groove 80e, the rear bearings 36 and 37 are preloaded and fixed in the axial direction.

  Here, the counter tool side end surface of the front bearing housing 20 has an inclined surface 20a that gradually inclines rearward toward the inner diameter side, and a part of the inward stepped portion 22 formed at the counter tool side end. Is disposed inside the aid coil 53 a of the stator 51. Further, the shoulder 81a of the flange 81 is also positioned closer to the stator than the tool side end surface 53a1 of the end coil 53a of the stator 51 of the built-in motor 50, and a part of the inner ring spacer 29 is also formed of the aid coil 53a of the stator 51. Arranged inside.

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 the inner periphery of the end coil 53 b on the side opposite to the tool of the stator 51. It is in the side.
With such an arrangement, the rotary shaft 80 can be shortened between the front bearing 26 and the rear bearing 36, and the draw bar 93 can also be shortened.

  Also, the outer diameter D of the inner ring spacer 29 that contacts the shoulder 81a is larger than the outer diameter d of the shoulder 81a, and the inner ring spacer 29 is provided around the end surface where the shoulder 81a and the inner ring spacer 29 contact. The space part s which the counter tool side end surface 29a faces is formed.

  In order to replace the front bearings 25 and 26, when the front bearings 25 and 26 are pulled out from the tool side, the front bearing fixing nut 86 is removed in a state where the outer cylinder housing 10 and the front housing 20 are separated, and the space portion s is removed. The inner ring spacer 29 is pushed from the arrow “a” by the jig arranged on the inner ring 25 to apply axial force to the inner rings 25 c and 26 c of the front bearings 25 and 26. In particular, in the angular ball bearings 25 and 26 of the back combination as in the present embodiment, it is necessary to apply an axial force to the inner ring 26c, and as shown in FIG. 4, an axial force is applied to the outer ring 26a. In this case, a ball b may occur.

As described above, in the spindle device M having the configuration of the present embodiment, the rotary shaft 80 has the shoulder 81a formed between the front bearing 26 and the rotor 52 of the built-in motor 50, and the shoulder 81a of the rotary shaft 80 and the front side An inner ring spacer 29 is arranged between the inner ring 26 c of the bearing 26. And since the shoulder part 81a of the rotating shaft 80 is located closer to the stator than the tool side end surface 53a1 of the end coil 53a of the stator 51 of the built-in motor 50, the axial direction length of the rotating shaft 80 is shortened, and the main shaft The total length can be shortened. In addition, a space portion s where the end face of the inner ring spacer 29 faces is formed around the opposing end faces of the shoulder portion 81a and the inner ring spacer 29. Therefore, when the front bearings 25 and 26 are pulled out, the inner ring spacer 29 is pulled out. Thus, an axial force can be applied to the inner ring 26c of the front bearing 26, and good maintainability can be obtained.
In addition, the eigenvalue of the rotating shaft 80 becomes higher due to the shortening of the rotating shaft 80, and the formation of the space portion s reduces the mass of the rotating body including the rotating shaft 80 and further increases the eigenvalue. Become. Thereby, the rotating shaft 80 can be rotated at a higher speed, and a synergistic effect that vibration at a high speed is reduced can be expected.
In the present embodiment, the space portion s is given by making the outer diameter of the inner ring spacer 29 larger than the outer diameter of the shoulder portion 81a.

  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. 5 is an enlarged cross-sectional view of the main part of the spindle device showing a first modification of the present invention. As shown in FIG. 5, a plurality of balance correction tap holes 82 to which a balance correction weight (set screw) (not shown) can be screwed in the flange portion 81 of the rotary shaft 80 to correct the balance of the rotary shaft 80. Is formed obliquely with respect to the rotation axis L. These tap holes 82 are opened in a tapered surface 81b formed between the axial end surface facing the inner ring spacer 29 and the outer peripheral surface. Further, the front bearing housing 20 has a tool insertion hole 21 (tool) inclined linearly along the axis of the tap hole 82 from the outside of the housing 20 to the tap hole 82 so as not to interfere with the end coil 53a 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 82. Therefore, the balance can be easily corrected after the spindle is assembled.

  6 (a) and 6 (b) are enlarged cross-sectional views of the main part of the spindle device showing a second modification of the present invention. In the second modification, the flange portion 81 of the rotating shaft 80 has an outer diameter d2 that is substantially equal to the outer diameter d1 of the rotor 52 between the shoulder portion 81a and the tool-side end surface of the rotor 52. Thereby, the thick part of the shaft diameter of the rotating shaft 80 increases, the bending rigidity of the rotating shaft can be increased, and the eigenvalue can be increased.

  6A, the space portion s is formed by a shoulder portion 81a having an outer diameter d smaller than the outer diameter d2 of the flange portion 81. In FIG. 6B, the space portion s is formed by the inner ring spacer 29. It is formed by a small diameter portion 29b formed at the end portion on the side opposite to the tool. Thereby, when pulling out the front bearings 25 and 26, a tool for pushing the inner ring spacer 29 in the axial direction can be inserted into the space portion s.

  The space portion s may be formed by both the shoulder portion 81a having a smaller diameter than the flange portion and the small diameter portion 29b formed at the tool side end portion of the inner ring spacer 29.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
In the above-described embodiment, two rows of angular ball bearings are used for the front bearing and the rear bearing, but the type and number of the bearings are not limited to this, and can be appropriately designed according to the state of use.

H housing M spindle device 10 outer cylinder housing 20 front bearing housing 25, 26 front bearing 29 inner ring spacer 30 rear bearing housing 36, 37 rear bearing 50 built-in motor 51 stator 52 rotor 53a, 53b end coil 80 rotating shaft 81 flange 81a Shoulder 86 Front bearing fixing nut s Space

Claims (5)

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.
The rotary shaft has a shoulder formed between the front bearing and the rotor of the built-in motor, and an inner ring spacer is disposed between the shoulder of the rotary shaft and the inner ring of the front bearing,
The shoulder of the rotating shaft is located closer to the stator than the tool side end surface of the end coil of the built-in motor stator,
A spindle device characterized in that a space portion is formed around the end surface where the shoulder portion and the inner ring spacer come into contact with each other so as to face the end surface of the inner ring spacer.   The spindle device according to claim 1, wherein an outer diameter of the inner ring spacer is larger than an outer diameter of the shoulder portion.   A tapping hole for balance correction is formed obliquely in the shoulder portion of the rotating shaft, and a balance correcting tool is inserted into the housing from the outside of the housing to the tapped hole. 3. A spindle device according to claim 1 or 2, characterized in that a possible tool insert is formed. The rotating shaft has a flange portion having an outer diameter dimension substantially equal to the outer diameter of the rotor between the shoulder portion and the tool side end surface of the rotor,
The said space part is formed by at least one of the said shoulder part smaller diameter than the said flange part, and the small diameter part formed in the tool side edge part of the said inner ring | wheel spacer. Main spindle apparatus of description.   A machine tool comprising: the spindle device according to claim 1; and a tilt mechanism for turning the spindle device.

Images