JP2009028803A - Main spindle apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a main spindle apparatus which can be used in a high speed rotation, and has high spindle stiffness. <P>SOLUTION: In the motor built-in type main spindle apparatus 1, a constant preload is applied to the bearings 15A, 15B, 17A, 17B of a first bearing portion 4 for supporting a rotary shaft 2 on the tool side with respect to a rotor 3, and a constant positional preload is applied to the bearings 22A, 22B of a second bearing portion 5 for supporting the rotary shaft 2 on the opposite side of the tool with respect to the rotor 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a spindle device, and more particularly to a spindle device capable of high-speed rotation used in a machine tool or the like.

  2. Description of the Related Art Conventionally, a motor built-in type spindle device that applies a constant pressure preload to a rolling bearing to support a spindle that rotates at high speed is known as a spindle device of a machine tool or the like (see, for example, Patent Document 1). As shown in FIG. 6, the spindle device 100 described in Patent Document 1 includes a housing 106 including a front cover 101, an outer cylinder 102, a rear cover 103, an inner housing 104, and a sleeve housing 105, and a front side of the housing 106. A set of angular ball bearings 107 arranged and a set of angular ball bearings 109 arranged on the rear side of the housing 106 are provided.

  A rotor 114 is fixed to a rotating shaft 113 that is rotatably supported by angular ball bearings 107 and 109, and a stator 115 is fixed to the outer cylinder 102 to constitute a built-in motor 116. A draw bar 117 is disposed in the rotating shaft 113. The outer ring of the rear angular ball bearing 109 is fitted and fixed to the bearing sleeve 111, and the outer ring of the front angular ball bearing 107 is fitted and fixed to the inner housing 104.

  The bearing sleeve 111 is slidably supported on the inner diameter surface of the sleeve housing 105. A preload spring 112 is disposed between the sleeve housing 105 and the bearing sleeve 111 to apply a constant pressure preload to the angular ball bearings 107 and 109.

7 includes a pair of rolling bearings 123 in which an outer ring is fitted into a housing 122, and a bearing sleeve 124 that is fitted in the housing 122 so as to be slidable in the axial direction. The bearing sleeve 124 includes a pair of rolling bearings 125 in which an outer ring is fitted, and a preload spring 126 disposed between the housing 122 and the bearing sleeve 124, and is disposed closer to the tool than the built-in motor 121. A constant pressure preload is applied to the rolling bearings 123 and 125. A cylindrical roller bearing 127 is disposed on the rear side of the built-in motor 121.
Japanese Patent Laid-Open No. 2004-195587

  By the way, when the constant pressure preload method is used as in the spindle device shown in FIGS. 6 and 7, the spindle device can be used at a higher speed than the spindle device using the fixed position preload, but the spindle rigidity is low. Since it is low, further improvement is desired. In particular, in the case of the spindle device shown in FIG. 7, a cylindrical roller bearing 127 is disposed on the rear side, and improvement is required even in use at high speed rotation.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a spindle device that can be used at high speed and has high spindle rigidity.

The above object of the present invention is achieved by the following configurations.
(1) a housing having a stator;
A rotating shaft having a rotor disposed opposite to the stator and capable of clamping a tool at one end;
A first bearing portion that supports the rotating shaft on the tool side with respect to the rotor;
A second bearing portion that supports the rotating shaft on the side opposite to the rotor with respect to the rotor;
A spindle device comprising:
A main shaft device, wherein a constant pressure preload is applied to the bearing of the first bearing portion, and a fixed position preload is applied to the bearing of the second bearing portion.
(2) a bearing sleeve that fits slidably in the axial direction with respect to the housing;
An outer ring is fitted in the housing, a front rolling bearing in which the inner ring is fitted on the rotating shaft, and an outer ring is fitted in the bearing sleeve on the opposite side of the front rolling bearing. Including an intermediate rolling bearing that is externally fitted to the rotating shaft, and the first bearing portion in which the front rolling bearing and the intermediate rolling bearing are combined on the back surface;
A preload application mechanism that is disposed between the housing and the bearing sleeve and applies a constant pressure preload to the front rolling bearing and the intermediate rolling bearing;
The spindle device according to (1), comprising:
(3) The spindle device according to (2), wherein the front rolling bearing and the intermediate rolling bearing are each composed of two angular ball bearings combined in parallel, and are combined with each other on the back surface. .
(4) The front rolling bearing is two angular ball bearings combined in parallel, and the intermediate rolling bearing is one angular ball bearing, which are combined on the back side. (2) Spindle device described in 1.

(5) It further includes another bearing sleeve that fits slidably in the axial direction with respect to the housing and into which the outer ring of the bearing of the second bearing portion is fitted.
The housing includes an intermediate housing to which the stator is attached, and a front housing that is detachably fastened to the intermediate housing and in which the first bearing portion is disposed.
The inner diameter of the stator is set larger than the outer diameter of the other bearing sleeve,
The subassembly including the front housing, the rotating shaft, the rotor, the first bearing portion, the second bearing portion, and the other bearing sleeve releases the fastening between the front housing and the intermediate housing. Thus, the spindle device according to any one of (1) to (4), wherein the spindle device can be integrally extracted from the intermediate housing to the tool side.
(6) The spindle device according to any one of (2) to (5), wherein a silicon oil having a kinematic viscosity at 40 ° C. of 5000 to 30000 cst is applied to the outer peripheral surface of the bearing sleeve.
(7) another bearing sleeve that is slidably fitted in the axial direction with respect to the housing;
The spindle device according to any one of (1) to (6), wherein the second bearing portion includes a pair of rolling bearings having different fitting dimensions between the other bearing sleeve and the outer ring.

(8) An outer ring presser having a flange portion that contacts the outer ring end surface of the intermediate rolling bearing and is fixed to the bearing sleeve, and has a flange portion facing the counter tool side end surface of the front housing;
An adjustment ring that is disposed between the end surface of the front housing on the side opposite to the tool and the flange portion of the outer ring presser, and regulates the amount of movement of the bearing sleeve relative to the front housing;
The spindle device according to any one of (2) to (7), comprising:
(9) The spindle device according to (8), wherein the adjustment ring is divided so as to be removable from a radial direction.

  According to the present invention, in the motor built-in type spindle device, the constant pressure preload is applied to the bearing of the first bearing portion that supports the rotating shaft on the tool side with respect to the rotor, and the rotating shaft on the counter tool side with respect to the rotor. A fixed position preload is applied to the bearing of the second bearing portion to be supported. Thus, in addition to the first bearing portion to which the constant pressure preload is applied, the second bearing portion to which the fixed position preload is applied can be used at high speed rotation and has high spindle rigidity. Can do.

  Further, the rotating shaft may be formed such that the outer diameter of the position supported by the first bearing portion is larger than the outer diameter of the position supported by the second bearing portion. Accordingly, since a bearing having a large bearing inner diameter is used for the first bearing portion, the spindle rigidity on the tool side can be increased, and a bearing having a small bearing inner diameter is used for the second bearing portion. High speed rotation can be allowed even in a bearing to which position preload is applied.

  Hereinafter, an embodiment of a spindle device according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the spindle device 1 according to the present embodiment is of a motor built-in type. The rotor 3 is fixed, and a rotary shaft 2 capable of clamping a tool (not shown) at one end and the tool side (from the rotor 3 ( Hereinafter, the first bearing portion 4 that supports the rotating shaft 2 on the front side), the second bearing portion 5 that supports the rotating shaft 2 on the side opposite to the tool from the rotor 3 (hereinafter also referred to as the rear side), and the housing 6. And comprising.

  The housing 6 is disposed between the front housing 7 in which the first bearing portion 4 is disposed, the rear housing 8 in which the second bearing portion 5 is disposed, and the front housing 7 and the rear housing 8. And an intermediate housing 9, which are detachably fastened by bolts or the like. A front cover 10 is disposed at the front end of the front housing 7, and a rear cover 11 is disposed at the rear end of the rear housing 8. A stator 13 is disposed in the intermediate housing 9 via a sleeve 12, and the rotor 3 fixed to the rotating shaft 2 is disposed opposite to the stator 13.

  As shown in FIG. 2, the first bearing portion 4 includes front rolling bearings 15 </ b> A and 15 </ b> B that are two angular ball bearings in which the outer ring 60 is fitted in the front housing 7 and the inner ring 61 is fitted on the rotating shaft 2. The intermediate rolling bearings 17A and 17B, which are two angular ball bearings in which the outer ring 62 is fitted into the bearing sleeve 16 and the inner ring 63 is fitted to the rotating shaft 2 on the side opposite to the tool from the front rolling bearings 15A and 15B. And having. The two front rolling bearings 15A and 15B and the two intermediate rolling bearings 17A and 17B are combined on the back side.

  Each of the inner rings 61 and 63 of the front rolling bearings 15A and 15B and the intermediate rolling bearings 17A and 17B has a rotating shaft 2 by a nut 65 fastened to the stepped portion 2a of the rotating shaft 2 and the rotating shaft 2 via a plurality of spacers 64. Is positioned against. Further, the outer rings 60 of the front rolling bearings 15A and 15B are positioned with respect to the front housing 7 by the stepped portion 7a of the front housing 7 and the front cover 10 fixed to the front housing 7 through a plurality of spacers 66. ing. Further, the outer rings 62 of the intermediate rolling bearings 17A and 17B are positioned with respect to the bearing sleeve 16 by the stepped portion 16a of the bearing sleeve 16 and the outer ring presser 20 fixed to the bearing sleeve 16 via a plurality of spacers 67. The

  The bearing sleeve 16 is fitted to the front housing 7 so as to be slidable in the axial direction. Further, a preload spring 18 which is a preload adding mechanism for biasing the front housing 7 and the bearing sleeve 16 in a direction away from each other is provided between the axially opposed surfaces of the front housing 7 and the bearing sleeve 16. Therefore, the front rolling bearings 15A and 15B and the intermediate rolling bearings 17A and 17B are given a constant pressure preload that maintains a constant preload by the preload spring 18 even if their relative positions change.

  As shown in FIG. 4, in the second bearing portion 5, an outer ring 70 is fitted in another bearing sleeve 21 that is slidably fitted in the rear housing 8, and an inner ring 71 is the rotor 3 of the rotating shaft 2. Further, two angular ball bearings (a pair of rolling bearings) 22A and 22B that are externally fitted on the side opposite to the tool and combined on the back surface are provided. Each inner ring 71 is positioned on the rotary shaft 2 together with the detected portion 75 constituting the speed sensor 74 by a stepped portion 2b of the rotary shaft 2 and a nut 73 fixed to the rotary shaft 2 through a plurality of spacers 72. Yes. Each outer ring 70 is fixed to the other bearing sleeve 21 by a stepped portion 21 a of the other bearing sleeve 21 and another outer ring presser 23 fixed to the other bearing sleeve 21 through a plurality of spacers 76. Yes. Thereby, fixed position preload is given to two angular ball bearings 22A and 22B.

  The fitting dimensions between the outer ring 70 of the two angular ball bearings 22A and 22B and the other bearing sleeve 21 are set to be different from each other. This is because one fitting gap is made larger than the normal fitting gap (about 3 to 8 μm), so that the thermal expansion of the outer ring during high-speed rotation and the expansion of the outer ring due to the centrifugal force of the ball are released, and the influence of the outer ring expansion. To ease. This suppresses an increase in internal preload and prevents seizure. In addition, by setting the other fitting gap to about 3 to 8 μm, it is possible to prevent a slide failure due to deterioration of the coaxiality. As shown exaggeratedly in FIG. 3, when the moment rigidity of the spindle device 1 is taken into consideration, the fitting gap g1 of the outer ring 70 of the angular ball bearing 22A may be made larger than the fitting gap g2 of the outer ring 70 of the angular ball bearing 22B. preferable.

  Further, as shown in FIG. 1, the rotating shaft 2 is configured such that the outer diameter d1 of the portion 2c supported by the first bearing portion 4 is larger than the outer diameter d2 of the portion 2d supported by the second bearing portion 5. May be formed. Accordingly, since the bearings 15A, 15B, 17A, and 17B having large bearing inner diameters are used for the first bearing part 4, the spindle rigidity on the tool side can be increased, and the second bearing part 5 has a bearing inner diameter of the bearing inner diameter. Since small bearings 22A and 22B are used, high-speed rotation can be allowed even in a bearing to which a fixed position preload is applied.

  Inside the rotary shaft 2, a draw bar 30 that is mounted so as to be movable relative to the rotary shaft 2 in the axial direction, and the draw bar 30 is provided between the rotary shaft 2 and the large-diameter portion 30 a of the draw bar 30. A plurality of springs 32 arranged to be compressible are arranged. The draw bar 30 pulls the tool holder 37 inward in the axial direction (rightward in FIG. 1) by the action of the spring 32. In addition, although the disc spring is used as the spring 32, you may use a coil spring, a helical disc spring, etc. FIG.

  A collet portion 38 that clamps the tool holder 37 is provided at the tip of the draw bar 30. A hydraulic clamp mechanism 40 is provided at the rear end of the draw bar 30. The hydraulic clamp mechanism 40 includes a cylinder 42 that includes a first pressure oil supply port 41 </ b> A and a second pressure oil supply port 41 </ b> B, and a piston 43 that moves within the cylinder 42. When pressure oil supplied from a hydraulic pump (not shown) is supplied from the first pressure oil supply port 41A to the cylinder 42, the piston 43 moves in the left direction in the figure to push the draw bar 30 toward the tool holder 37, and the unclamped state It becomes. When pressure oil is supplied to the second pressure oil supply port 41 </ b> B, the piston 43 moves in the right direction, and the draw bar 30 clamps the tool holder 37.

  Further, in the present embodiment, the inner diameter D of the stator 13 is a component attached to the rotary shaft 2 on the side opposite to the tool from the stator 13, that is, the outer diameter Da of the rotor 3, the outer diameter Db of the other bearing sleeve 21, and the speed. The outer diameter Dc of the detected part 75 constituting the sensor 74 is set larger. Therefore, by removing the bolts, the subassembly U including the front housing 7 having the first bearing portion 4, the rotating shaft 2, the rotor 3, the second bearing portion 5, the other bearing sleeve 21, and the like is replaced with the intermediate housing 9. It is possible to remove it from the tool to the tool side, and the maintenance is greatly improved.

  The radial clearance between the front housing 7 and the bearing sleeve 16 and the radial clearance between the rear housing 8 and the other bearing sleeve 21 are the sleeve size, the required rigidity, the thermal expansion caused by the heat generated by the rotation of the rotary shaft 2, etc. For example, it is designed by appropriately selecting from the range of 10 to 70 μm. In addition, high-viscosity silicone oil having a kinematic viscosity at 40 ° C. of 5000 to 30000 cst (10000 cst in this embodiment) is applied to these radial gaps. As a result, when the bearing sleeve 16 and the other bearing sleeve 21 vibrate, the shear resistance of the high-viscosity silicone oil interposed between the front housing 7 and the bearing sleeve 16 and between the rear housing 8 and the other bearing sleeve 21. Vibration can be effectively damped.

  Further, as shown in FIG. 2, the outer ring presser 20 fastened and fixed to the side surface of the bearing sleeve 16 with a bolt is in contact with the outer ring of the intermediate rolling bearing 17 </ b> B and is opposed to the non-tool side end surface of the front housing 7. Part 20a. An adjustment ring 19 fixed to the flange portion 20a is disposed between the end surface on the side opposite to the tool of the front housing 7 and the flange portion 20a of the outer ring presser 20. The adjustment ring 19 defines a gap Δ1 between the tool-side side surface 19a of the adjustment ring 19 and the opposite tool-side end surface 7a of the front housing 7, and regulates the amount of movement of the bearing sleeve 16 relative to the front housing 7.

  The clearance Δ1 between the tool side end surface 19a of the adjustment ring 19 and the counter tool side end surface 7a of the front housing 7 is set to be smaller than the axial movement allowable amount Δ2 of the balls 68 of the front side rolling bearings 15A and 15B.

  Here, the axial movement allowable amount Δ2 of the ball 68 is determined by the shapes of the bearings 15A and 15B. Specifically, as shown in FIG. 5A, the ball diameter is Da, the outer ring groove radius is re, the inner ring groove radius is ri, the outer ring raceway maximum diameter is φde, the inner ring raceway minimum diameter is φDi, and the counter bore base of the outer ring 60 ( As shown in FIG. 5B, when the inner ring 61 is fixed and the outer ring 60 is moved to the right side in the drawing with respect to the bearings 15A and 15B where the height from the boundary between the outer ring raceway and the outer ring raceway maximum diameter is w. It will be a positional relationship.

  From the positional relationship as shown in FIG. 5B, the axial movement allowable amount Δ2 is given by Δ2 = δ2−δ1. Here, δ1 is given by δ1 = (Da−ri) · sin θ1, and θ1 is a straight line passing through the counterbore base and a straight line connecting the counterbore base and the center of curvature O1 of the inner ring groove radius. The angle to make. Further, δ2 is given by δ2 = re · sin θ2, and θ2 is an angle formed by a straight line passing through the curvature center O2 of the outer ring groove radius and a straight line connecting the curvature center O2 and the counterbore base. .

  When pressure oil is supplied from the first pressure oil supply port 41A to the cylinder 42 and the draw bar 30 is pushed out to the tool holder 37 side (unclamped state), the rotary shaft 2 is moved forward (in FIG. 1) by the spring force of the disc spring 32. The front side rolling bearings 15A and 15B and the inner ring 61 and 63 of the intermediate rolling bearings 17A and 17B that are pressed in the left direction) and fitted and fixed to the rotary shaft 2 also move leftward together with the bearing sleeve 16.

  At this time, if the moving amount of the inner ring 61 of the front rolling bearings 15A and 15B increases, the ball 68 is detached from the outer ring 60 and is damaged, but the moving amount of the inner ring 61 is adjusted by the adjusting ring 19 fixed to the bearing sleeve 16. Of the ball 68 is limited to be smaller than the axial movement allowable amount Δ2 of the ball 68. Thus, preload loss that has a significant effect on the front rolling bearings 15A and 15B does not occur, and damage to the front rolling bearings 15A and 15B can be prevented even if the rotary shaft 2 rotates. .

  Moreover, since the adjustment ring 19 is a pair of substantially semicircular arc plate members, it can be attached and detached from the radial direction as shown by a one-dot chain line in FIG. Therefore, even when the bearing sleeve 16 for applying the constant pressure preload is arranged on the tool side (front side) from the rotor 3, the adjustment ring 19 having a predetermined thickness is removed after the subassembly U is removed from the intermediate housing 9. By exchanging from the radial direction, it is possible to easily adjust the gap without disassembling the first bearing portion 4 and the bearing sleeve 16 from the front housing 7.

  As described above, according to the spindle device 1 of the present embodiment, constant pressure preload is applied to the bearings 15A, 15B, 17A, and 17B of the first bearing portion 4 that supports the rotary shaft 2 on the tool side with respect to the rotor 3. The fixed position preload is applied to the bearings 22 </ b> A and 22 </ b> B of the second bearing portion 5 that supports the rotating shaft 2 on the side opposite to the tool with respect to the rotor 3. Thereby, in addition to the 1st bearing part 4 to which a constant pressure preload is provided, the 2nd bearing part 5 to which a fixed position preload is provided can be used at high speed rotation, and high spindle rigidity can be achieved. Can have. Therefore, the spindle device 1 can be used in a region where the dmN value exceeds 1.8 million, and even in a region where it exceeds 2 million, which is difficult with the conventional spindle device that is grease lubricated. Further, by using such a spindle device 1 as a spindle of a machine tool, high-speed and high-precision machining can be performed.

  The spindle device 1 includes a bearing sleeve 16 that is slidably fitted in the axial direction with respect to the housing 6, and an outer ring 60 that is fitted in the housing 6, and an inner ring 61 that is fitted on the rotary shaft 2. The front rolling bearings 15A and 15B, and the intermediate rolling bearing 17A and the outer ring 62 are fitted into the bearing sleeve 16 and the inner ring 63 is fitted to the rotary shaft 2 on the opposite side of the front rolling bearings 15A and 15B. 17B, and the front rolling bearings 15A and 15B and the intermediate rolling bearings 17A and 17B are disposed between the first bearing portion 4 and the housing 6 and the bearing sleeve 16, and the front rolling bearings 15A and 15B. A preload spring 18 that applies a constant pressure preload to the intermediate rolling bearings 17A and 17B. Thereby, the 1st bearing part 5 to which a constant pressure preload is provided by the tool side with respect to the rotor 3 can be comprised.

  The front rolling bearings 15A and 15B and the intermediate rolling bearings 17A and 17B can be arbitrarily set in size and type. For example, as in the present embodiment, the front rolling bearings 15A and 15B and the intermediate rolling bearings 17A and 17B are composed of two angular ball bearings that are combined in parallel with each other, and are combined with each other on the back surface. When a thrust force is applied during unclamping, the bearing sleeve 16 can be slid stably, and a stable constant pressure preload can be applied. In addition, when two angular contact ball bearings with front rolling bearings combined in parallel and one angular contact ball bearing with an intermediate rolling bearing are combined with each other on the back, the load is received by the two front rolling bearings. Thus, the length of the spindle device 1 can be shortened without reducing the load performance.

  The spindle device 1 includes another bearing sleeve 21 that is slidably fitted in the axial direction with respect to the housing 6 and in which the outer rings 70 of the bearings 22A and 22B of the second bearing portion 5 are fitted. Further prepare. The housing 6 includes an intermediate housing 9 to which the stator 13 is attached, and a front housing 7 that is detachably fastened to the intermediate housing 9 and in which the first bearing portion 4 is disposed, and the inner diameter D of the stator 13 is The outer diameter Db of the other bearing sleeve 21 is set larger. Therefore, the subassembly U having the front housing 7, the rotating shaft 2, the rotor 3, the first bearing portion 4, the second bearing portion 5, and the other bearing sleeve 21 is fastened between the front housing 7 and the intermediate housing 9. Is released from the intermediate housing 9 to the tool side.

  Therefore, since the subassembly U can be extracted from the housing 6, the assemblability is improved and can be quickly replaced at the time of breakage, so that the maintainability is greatly improved. Further, if the subassembly U is stocked by performing a running-in operation using another housing in advance, if the rotating shaft is damaged, it can be recovered immediately by replacing the subassembly.

  In addition, since silicon oil having a kinematic viscosity of 5,000 to 30,000 cst at 40 ° C. is applied to the outer peripheral surface of the bearing sleeve 16, even with a slight vibration amplitude, it effectively absorbs vibration energy and has an excellent damping function. A spindle device having the same is obtained. Moreover, according to the machine tool provided with such a spindle device, machining with high machining accuracy is possible.

  Furthermore, since the second bearing portion 5 includes a pair of rolling bearings 22A and 22B having different fitting dimensions between the other bearing sleeve 21 and the outer ring, the second bearing portion 5 can be operated while maintaining good coaxiality and maintaining stable rotation. It is possible to prevent seizure by absorbing thermal expansion of the outer ring caused by heat or the like.

  In addition, the spindle device 1 is fixed to the bearing sleeve 16 in contact with the outer ring end surface of the intermediate rolling bearing 17B, and has an outer ring presser 20 having a flange portion 20a facing the counter tool side end surface 7b of the front housing 7. An adjustment ring 19 is provided between the non-tool side end surface 7 b of the front housing 7 and the flange portion 20 a of the outer ring retainer 20 and restricts the amount of movement of the bearing sleeve 16 relative to the front housing 7. Thereby, at the time of unclamping or the like, the amount of movement of the inner ring 61 of the front rolling bearings 15A and 15B is regulated by the force acting on the rotating shaft, and damage to the front rolling bearings 15A and 15B due to preload loss can be prevented. .

  Further, since the adjustment ring 19 is divided so as to be detachable from the radial direction, the axial direction of the intermediate rolling bearings 17A and 17B can be obtained without disassembling the first bearing portion 4 and the bearing sleeve 16 from the front housing 7. The adjustment ring 19 for adjusting the moving distance can be easily replaced.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.

It is a longitudinal cross-sectional view of the main shaft apparatus which is one Embodiment of this invention. It is an enlarged view of the part enclosed by II of FIG. It is a figure which shows the position of the adjustment ring seen from the III direction of FIG. FIG. 4 is an enlarged view of a portion surrounded by IV in FIG. 1. It is a figure for demonstrating the axial direction movement allowance of the ball | bowl of an angular contact ball bearing. It is a longitudinal cross-sectional view of the conventional spindle device. It is a longitudinal cross-sectional view of another conventional spindle device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main shaft apparatus 2 Rotating shaft 3 Rotor 4 1st bearing part 5 2nd bearing part 6 Housing 7 Front housing 9 Intermediate housing 13 Stator 15A, 15B Angular contact ball bearing (front side rolling bearing, bearing of 1st bearing part)
16 Bearing sleeve 17A, 17B Angular contact ball bearing (intermediate rolling bearing, first bearing bearing)
18 Preload spring (preload addition mechanism)
19 Adjustment ring 21 Other bearing sleeve 22A, 22B Angular contact ball bearing (bearing of the second bearing portion)
U subassembly

Claims (9)

A housing having a stator;
A rotating shaft having a rotor disposed opposite to the stator and capable of clamping a tool at one end;
A first bearing portion that supports the rotating shaft on the tool side with respect to the rotor;
A second bearing portion that supports the rotating shaft on the side opposite to the rotor with respect to the rotor;
A spindle device comprising:
A main shaft device, wherein a constant pressure preload is applied to the bearing of the first bearing portion, and a fixed position preload is applied to the bearing of the second bearing portion. A bearing sleeve slidably fitted in the axial direction with respect to the housing;
An outer ring is fitted in the housing, a front rolling bearing in which the inner ring is fitted on the rotating shaft, and an outer ring is fitted in the bearing sleeve on the opposite side of the front rolling bearing. Including an intermediate rolling bearing that is externally fitted to the rotating shaft, and the first bearing portion in which the front rolling bearing and the intermediate rolling bearing are combined on the back surface;
A preload application mechanism that is disposed between the housing and the bearing sleeve and applies a constant pressure preload to the front rolling bearing and the intermediate rolling bearing;
The spindle apparatus according to claim 1, comprising:   3. The spindle device according to claim 2, wherein the front rolling bearing and the intermediate rolling bearing are each composed of two angular ball bearings combined in parallel, and are combined with each other on the back side.   The said front side rolling bearing is two angular contact ball bearings combined in parallel, and the said intermediate rolling bearing is one angular contact ball bearing, and they are mutually back combined. Spindle device. A bearing sleeve that is slidably fitted in the axial direction with respect to the housing, and in which an outer ring of a bearing of the second bearing portion is fitted;
The housing includes an intermediate housing to which the stator is attached, and a front housing that is detachably fastened to the intermediate housing and in which the first bearing portion is disposed.
The inner diameter of the stator is set larger than the outer diameter of the other bearing sleeve,
The subassembly including the front housing, the rotating shaft, the rotor, the first bearing portion, the second bearing portion, and the other bearing sleeve releases the fastening between the front housing and the intermediate housing. Thus, the spindle device according to any one of claims 1 to 4, wherein the spindle device can be integrally extracted from the intermediate housing to the tool side.   6. The spindle device according to claim 2, wherein a silicon oil having a kinematic viscosity of 5000 to 30000 cst at 40 ° C. is applied to the outer peripheral surface of the bearing sleeve. Another bearing sleeve fitted to the housing so as to be slidable in the axial direction;
The spindle device according to any one of claims 1 to 6, wherein the second bearing portion includes a pair of rolling bearings having different fitting dimensions between the other bearing sleeve and the outer ring. An outer ring presser having a flange portion which is in contact with an outer ring end surface of the intermediate rolling bearing and fixed to the bearing sleeve and which faces a counter tool side end surface of the front housing;
An adjustment ring that is disposed between the end surface of the front housing on the side opposite to the tool and the flange portion of the outer ring presser, and regulates the amount of movement of the bearing sleeve relative to the front housing;
The spindle device according to any one of claims 2 to 7, further comprising:   The spindle device according to claim 8, wherein the adjustment ring is divided so as to be detachable from a radial direction.

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