Spindle and machining apparatus including the same

Abstract

To provide a spindle which inhibits chips adhering thereto from hindering rotation of a main shaft.SOLUTION: A spindle 62 includes: a housing 63 provided with a first opening 63A; a first bearing 64A housed in the housing 63; a main shaft 65 rotatably supported by the first bearing 64A; a collet chuck 67 which is inserted into a through hole 65H formed at the main shaft 65 and configured to be able to hold a processing tool 6A and be movable in an axial direction K; a draw bar 68 connected to the collet chuck 67; and a cover member 72 which covers the first opening 63A and is provided with a through hole 72H into which the main shaft 65 is inserted. The main shaft 65 and the cover member 72 are disposed spaced apart from each other.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a spindle and a cutting device equipped with the same.

Background Art

[0002] Conventionally, a cutting device that processes a workpiece using a rotating cutting tool has been known. In this cutting device, while changing the relative positional relationship between the workpiece and the cutting tool three-dimensionally, the cutting tool is brought into contact with the workpiece at a predetermined angle to process the workpiece into a desired shape.

[0003] For example, Patent Document 1 discloses a cutting device including a spindle rotatably supported by a bearing, a collet chuck inserted into a through hole formed in the spindle and capable of gripping a cutting tool, and a housing that houses these components. The cutting tool is detachably gripped by the collet chuck of the spindle, and the workpiece is fixed to a holding member. The spindle can be freely moved, for example, in the Y-axis direction and the Z-axis direction of the XYZ orthogonal coordinate system of the machining space, and the cutting tool is configured to be rotatable around the Z-axis. Further, the holding member can be freely moved, for example, in the X-axis direction of the machining space, and the workpiece is configured to be rotatable around the X-axis and the Y-axis.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when machining a workpiece, since the spindle rotates, a gap is required between the housing that houses the spindle and the spindle. When machining a workpiece, cutting powder is generated, and this cutting powder may enter the above gap. If a large amount of cutting powder adheres to the gap, the rotation of the spindle will be inhibited, and it will be difficult to machine the workpiece with a machining tool.

[0006] The present invention has been made in view of such a point, and an object thereof is to provide a spindle in which the inhibition of the rotation of the spindle due to the adhesion of cutting powder is suppressed.

Means for Solving the Problems

[0007] The inventors of the present application focused on the position of the gap between the spindle that rotates at high speed and the cover member attached to the housing. When the spindle and the cover member rotate integrally, the cutting powder attached to the cover member moves outward due to the centrifugal force generated by the rotation of the spindle. For this reason, it was found that the more the position of the gap is away from the spindle, the more cutting powder moves into the gap and adheres. Therefore, it was found that by bringing the position of the gap closer to the spindle, it becomes difficult for cutting powder to adhere to the gap.

[0008] The spindle according to the present invention includes a housing in which a first opening and a second opening are formed, a bearing housed in the housing, a main shaft rotatably supported by the bearing and having a through hole formed therethrough in the axial direction, the main shaft being located on one side in the axial direction and on the first opening side and having a first end extending from the first opening to the outside of the housing and a second end located on the other side in the axial direction and on the second opening side, a third end located on the first end side of the main shaft and capable of gripping a machining tool for machining a workpiece, and a fourth end located on the second end side of the main shaft, a collet chuck inserted into the through hole and configured to be movable in the axial direction, a fifth end located on the first end side of the main shaft and connected to the fourth end of the collet chuck, and a sixth end located on the second end side of the main shaft, a drawbar inserted into the through hole and configured to be movable in the axial direction, and a cover member covering the first opening and having a through hole through which the main shaft is inserted. The main shaft and the cover member are spaced apart from each other.

[0009] According to the spindle of the present invention, the main shaft is inserted into the through hole formed in the cover member, and the main shaft and the cover member are spaced apart from each other. That is, since a gap is formed on the side of the main shaft, the cover member does not rotate even when the main shaft rotates. Therefore, even when the area of the cover member is relatively large, the cutting powder adhering to the cover member is not affected by the centrifugal force caused by the rotation of the main shaft and does not move. Thus, by providing a gap on the side of the main shaft, it is possible to reduce the cutting powder adhering to the gap.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a spindle in which the inhibition of the rotation of the main shaft due to the adhesion of cutting powder is suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

MODE FOR CARRYING OUT THE INVENTION

[0012] Hereinafter, with reference to the drawings, a spindle unit and a cutting device according to an embodiment of the present invention will be described. Note that the embodiments described here are not intended to limit the present invention. In addition, members and parts having the same function are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified as appropriate.

[0013] FIG. 1 is a perspective view of the cutting device 10. FIG. 2 is a front view of the cutting device 10. FIG. 3 is a cross-sectional view of the cutting device 10. In the following description, when the cutting device 10 is viewed from the front, the direction away from the cutting device 10 is defined as the front, and the direction approaching the cutting device 10 is defined as the rear. Left, right, up, and down respectively mean left, right, up, and down when the cutting device 10 is viewed from the front. Also, in the drawings, the symbols F, Rr, L, R, U, and D respectively mean front, rear, left, right, up, and down. In the present embodiment, the cutting device 10 is arranged in an XYZ orthogonal coordinate system. Here, the X-axis is an axis extending in the front-rear direction. As shown in FIG. 3, in the present embodiment, the X-axis is inclined by θ from the horizontal direction. Note that the X-axis may extend in the same direction as the horizontal direction. The Y-axis is an axis extending in the left-right direction. The Z-axis is an axis extending in the up-down direction. As shown in FIG. 3, in the present embodiment, the Z-axis is inclined by θ from the vertical direction. Note that the Z-axis may extend in the same direction as the vertical direction. Also, the symbols θ X , θ Y , θ Z respectively indicate the rotational directions around the X-axis, Y-axis, and Z-axis. However, the directions described above are only defined for convenience of explanation and do not limit the installation mode of the cutting device 10 in any way, nor do they limit the present invention in any way.

[0014] The cutting device 10 is a device for machining (e.g., cutting) a workpiece 5 (see FIG. 4) and, if necessary, polishing it. The cutting device 10 is a device for machining the workpiece 5 to produce dental shaped products, such as crowns, inlays, onlays, veneers and other crown prostheses, artificial teeth, denture bases, etc. The shape of the workpiece 5 is, for example, block-shaped (e.g., prismatic). The workpiece 5 may be disc-shaped. The workpiece 5 is formed of various materials such as resins (resin materials) such as PMMA (polymethyl methacrylate resin), PEEK (polyetheretherketone resin), hybrid resin, ceramic materials such as glass ceramics, zirconia, wax, gypsum, etc. When zirconia is used as the material of the workpiece 5, for example, semi-sintered zirconia is used. However, the shape and material of the workpiece 5 are not particularly limited.

[0015] As shown in FIG. 4, in this embodiment, an adapter 8 (also referred to as a holder) is attached to the workpiece 5. With the adapter 8 attached, the workpiece 5 is housed in the cutting device 10 and machined. Here, the adapter 8 includes a plate-like member 8A and a connecting pin 8B. The plate-like member 8A is connected to the workpiece 5. The connecting pin 8B protrudes from the plate-like member 8A. The connecting pin 8B is inserted into an insertion hole 50A (see FIG. 3) of a clamp 50 described later. The adapter 8 holds the workpiece 5.

[0016] As shown in FIG. 1, the cutting device 10 is formed in a box shape. The cutting device 10 includes a case body 12, a front cover 25, and a control device 48. The case body 12 has a lower wall 13, a left wall 14 (see also FIG. 2), a right wall 15, a rear wall 16 (see also FIG. 3), an upper wall 17, a front wall 18, a partition bottom wall 19 (see FIG. 3), a partition rear wall 20 (see FIG. 2), a partition upper wall 21 (see FIG. 3), and a partition side wall 23 (see FIG. 3). The left wall 14 extends upward from the left end of the lower wall 13. The right wall 15 extends upward from the right end of the lower wall 13. The rear wall 16 extends upward from the rear end of the lower wall 13. The left end of the rear wall 16 is connected to the rear end of the left wall 14, and the right end of the rear wall 16 is connected to the rear end of the right wall 15. The front wall 18 extends upward from the front end of the lower wall 13. The left end of the front wall 18 is connected to the front end of the left wall 14, and the right end of the front wall 18 is connected to the front end of the right wall 15. An opening 18A (see FIG. 2) is formed in the front wall 18. The upper wall 17 is connected to the upper ends of the left wall 14, the right wall 15, the rear wall 16, and the front wall 18, respectively. As shown in FIG. 3, the partition bottom wall 19 is disposed above the lower wall 13. The partition upper wall 21 is disposed above the partition bottom wall 19 and below the upper wall 17. The partition rear wall 20 is disposed in front of the rear wall 16 and behind the front wall 18. The partition side wall 23 is disposed to the right of the left wall 14 and to the left of the right wall 15. The partition side wall 23 extends upward from the partition bottom wall 19. The partition side wall 23 is connected to the partition bottom wall 19, the partition upper wall 21, and the partition rear wall 20.

[0017] As shown in FIG. 3, an internal space 26 surrounded by the partition bottom wall 19, the left wall 14 (see FIG. 2), the partition rear wall 20, the partition upper wall 21, the partition side wall 23, and the front wall 18 is formed in the cutting device 10. The internal space 26 is a processing area where the workpiece 5 is processed. An accommodation space 27 (see FIG. 2) surrounded by the partition bottom wall 19, the right wall 15 (see FIG. 2), the partition rear wall 20, the partition upper wall 21, the partition side wall 23, and the front wall 18 is formed in the cutting device 10. A moving mechanism 58 described later is accommodated in the accommodation space 27.

[0018] As shown in FIG. 2, the front cover 25 is provided so as to be vertically movable at the front ends of the left wall 14 and the right wall 15. When the front cover 25 moves upward and the front cover 25 opens, the internal space 26 communicates with the outside. When the front cover 25 moves downward and the front cover 25 closes, the internal space 26 is isolated from the outside. FIG. 2 shows a state in which the front cover 25 has moved upward and the internal space 26 communicates with the outside. A window 26A is provided in the front cover 25. The window 26A is formed of, for example, a transparent acrylic plate. An operator can visually recognize the internal space 26 through the window 26A. The window 26A is smaller than the opening 18A formed in the front wall 18.

[0019] As shown in FIG. 2, the cutting device 10 includes a spindle unit 60, a carriage 38, a tool magazine 40 (see also FIG. 5), a clamp 50, and a moving mechanism 58. A part of the spindle unit 60 and the carriage 38 are arranged in an accommodation space 28 (see FIG. 3) surrounded by a partition upper wall 21, a left wall 14, a right wall 15, a partition rear wall 20, an upper wall 17, and a front wall 18. Another part of the spindle unit 60 is arranged in the internal space 26. The spindle unit 60 is inserted through an opening 21H (see FIG. 3) formed in the partition upper wall 21. The tool magazine 40 and the clamp 50 are arranged in the internal space 26. The carriage 38 is an example of a unit moving device. The spindle unit 60 is mounted on the carriage 38. The carriage 38 is provided so as to be movable in the Z-axis direction and the Y-axis direction. The carriage 38 moves the spindle unit 60 in the Z-axis direction and the Y-axis direction. The carriage 38 includes a first carriage 38A and a second carriage 38B. The first carriage 38A is supported by a pair of first guide shafts 39A extending in the Y-axis direction. The first carriage 38A can move in the Y-axis direction along the first guide shaft 39A by a first drive mechanism 38C (see FIG. 11). The first guide shaft 39A is provided in the accommodation space 28 (see FIG. 3). The left end of the first guide shaft 39A is connected to the left wall 14. The right end of the first guide shaft 39A is connected to the right wall 15. The second carriage 38B is supported by a pair of second guide shafts 39B extending in the Z-axis direction. The second carriage 38B can move in the Z-axis direction along the second guide shaft 39B by a second drive mechanism 38D (see FIG. 11). The second guide shaft 39B is provided on the first carriage 38A. Therefore, when the first carriage 38A moves in the Y-axis direction, the second carriage 38B also moves in the Y-axis direction in the same manner. The first drive mechanism 38C and the second drive mechanism 38D are controlled by the control device 48.

[0020] As shown in FIG. 2, the moving mechanism 58 is disposed in the accommodation space 27. The moving mechanism 58 is disposed to the right of the tool magazine 40. The moving mechanism 58 includes a shaft 58A extending in the Y-axis direction. A part (right end portion) of the shaft 58A is disposed in the accommodation space 27, and another part (left end portion) of the shaft 58A is disposed in the internal space 26. The tool magazine 40 is provided at the left end portion of the shaft 58A. The moving mechanism 58 is configured to be movable in the X-axis direction by a third drive mechanism 58B (see FIG. 11). The moving mechanism 58 is a mechanism for moving the tool magazine 40 in the X-axis direction. The third drive mechanism 58B is controlled by the control device 48.

[0021] As shown in FIG. 5, the tool magazine 40 is capable of accommodating a plurality of machining tools 6A and detection tools 6B. The tool magazine 40 is provided between the clamp 50 and the moving mechanism 58. The tool magazine 40 moves in the X-axis direction when the moving mechanism 58 moves in the X-axis direction. The tool magazine 40 includes a first portion 40A that accommodates the machining tools 6A and the detection tools 6B, a second portion 40B that is disposed behind the first portion 40A and is connected to the shaft 58A, and a third portion 40C that is disposed behind the second portion 40B. A plurality (here, six) of through-hole portions 42A for accommodating the machining tools 6A are formed in the first portion 40A of the tool magazine 40. The through-hole portions 42A penetrate the tool magazine 40 in the vertical direction. The machining tools 6A and the detection tools 6B are respectively inserted into the through-hole portions 42A with their upper portions exposed. When replacing the machining tool 6A or the detection tool 6B, the machining tool 6A or the detection tool 6B held by the collet chuck 67 of the spindle 62 described later is returned to the through-hole portion 42A. Then, the spindle unit 60 is moved to a position above the machining tool 6A or the detection tool 6B to be used next, and the upper end of the machining tool 6A or the detection tool 6B located below the collet chuck 67 is gripped by the collet chuck 67.

[0022] The processing tool 6A is formed in a rod shape. The processing tool 6A is used when processing the workpiece 5. The processing tool 6A gradually wears out by processing the workpiece 5. The processing tool 6A is formed of a conductive material such as metal. The detection tool 6B is formed in a rod shape. The detection tool 6B is used only when performing automatic correction to appropriately correct the relative positional relationship between the workpiece 5 (i.e., the tool magazine 40 and the clamp 50) and the spindle unit 60. The detection tool 6B is formed of a conductive material such as metal.

[0023] As shown in FIG. 2, inside the shaft 58A, a rotating shaft 44 that rotatably supports the clamp 50 is provided. The rotating shaft 44 extends in the left - right direction and is connected to the clamp 50 and the moving mechanism 58. The moving mechanism 58 is provided with a drive motor 44A (also refer to FIG. 11). The drive motor 44A is controlled by the control device 48. The rotating shaft 44 is configured to be rotatable about the Y - axis by θ Y When the rotating shaft 44 rotates about the Y - axis by θ Y the clamp 50 rotates about the Y - axis by θ Y It should be noted that the rotating shaft 44 is configured to be rotatable independently of the shaft 58A. That is, even when the rotating shaft 44 rotates about the Y - axis by θ Y the shaft 58A does not rotate about the Y - axis by θ Y

[0024] ​As shown in FIG. 6, the clamp 50 is provided at the left end of the rotation shaft 44. The clamp 50 is disposed to the left of the tool magazine 40. The clamp 50 is a member that detachably holds the adapter 8. The clamp 50 holds the workpiece 5 via the adapter 8. The clamp 50 is an example of a holding member. As shown in FIG. 3, a plurality of insertion holes 50A are formed in the clamp 50. Here, three insertion holes 50A are arranged in the front-rear direction. The connection pin 8B (see FIG. 4) of the adapter 8 is inserted into the insertion hole 50A. The connection pin 8B inserted into the insertion hole 50A is fixed to the clamp 50 by a screw 50B (see FIG. 5). The clamp 50 is configured to be movable together with the tool magazine 40. That is, the tool magazine 40 and the clamp 50 are configured to be movable in the X-axis direction by a movement mechanism 58. Note that even if the clamp 50 rotates by θ Y about the Y-axis, the tool magazine 40 does not rotate by θ Y about the Y-axis.

[0025] As shown in FIG. 7, the spindle unit 60 includes a spindle 62 and an actuator 61 (see FIG. 3). As shown in FIG. 3, the actuator 61 is detachably provided on the upper part of the spindle 62. The actuator 61 controls the vertical movement of a drawbar 68 (see FIG. 7) of the spindle 62 described later. That is, the actuator 61 controls the attachment and detachment of the machining tool 6A and the detection tool 6B by a collet chuck 67 of the spindle 62 described later.

[0026] As shown in FIG. 7, the spindle 62 includes a housing 63, a first bearing 64A, a second bearing 64B, a third bearing 64C, a main shaft 65, a spindle motor 66, a collet chuck 67, a drawbar 68, a biasing member 70, a stopper 71, a cover member 72, a first fixing member 74, a second fixing member 76, a third fixing member 78, a coolant housing 80, an air inlet 90, an air flow path 94 (see FIG. 8), and an air outlet 96 (see FIG. 8). Here, the upper and lower sides of the spindle 62 mean, for example, the upper and lower sides along the axial direction K of the main shaft 65 (that is, the upper and lower sides with reference to the axial direction K). The axial direction K of the present embodiment is parallel to the Z-axis. That is, the axial direction K is inclined by θ from the vertical direction.

[0027] As shown in FIG. 7, the housing 63 is formed in a substantially cylindrical shape. The housing 63 is formed with a first opening 63A located on the lower side and a second opening 63B located on the upper side. The housing 63 has a first bearing holding portion 63C located on the first opening 63A side and a second bearing holding portion 63D located on the second opening 63B side. The first bearing holding portion 63C holds a part of the first bearing 64A and the second bearing 64B. The second bearing holding portion 63D holds the third bearing 64C. A through hole 63DH through which compressed air supplied from a compressor 98 (see FIG. 11) described later passes is formed in the second bearing holding portion 63D. The through hole 63DH penetrates the second bearing holding portion 63D in the vertical direction. A plurality of through holes 63CH (also see FIG. 9) are formed in the first bearing holding portion 63C. Here, four through holes 63CH are arranged at equal intervals (intervals of 90°) in the circumferential direction. Note that the number of the through holes 63CH is not limited to four. The through hole 63CH penetrates the first bearing holding portion 63C in the vertical direction. The through hole 63CH is located outside the first bearing 64A and the second bearing 64B.

[0028] As shown in FIG. 7, the first bearing 64A, the second bearing 64B, and the third bearing 64C are housed in the housing 63. The first bearing 64A and the second bearing 64B are located on the side of the first opening 63A of the housing 63. The second bearing 64B is disposed above the first bearing 64A. The first bearing 64A and the second bearing 64B are held by the first fixing member 74 and the second fixing member 76. More specifically, the first bearing 64A is directly held by the first fixing member 74 and the second fixing member 76, and the second bearing 64B is indirectly held by the first fixing member 74 and the second fixing member 76 via the first bearing 64A. The third bearing 64C is located on the side of the second opening 63B of the housing 63. The third bearing 64C is held by the second bearing holder 63D. The third bearing 64C is disposed above the second bearing 64B. The first bearing 64A, the second bearing 64B, and the third bearing 64C rotatably support the main shaft 65. The first bearing 64A is an example of a bearing.

[0029] As shown in FIG. 7, the main shaft 65 extends in the vertical direction. The main shaft 65 is housed in the housing 63. The main shaft 65 is rotatably supported by the first bearing 64A, the second bearing 64B, and the third bearing 64C. A through hole 65H penetrating in the axial direction K (here, the vertical direction) is formed in the main shaft 65. The main shaft 65 has a first end 65A and a second end 65B. The first end 65A is located on one side (here, the lower side) of the axial direction K. The first end 65A is located on the side of the first opening 63A. The first end 65A extends outside the housing 63 from the first opening 63A. The first end 65A is located outside the housing 63. The second end 65B is located on the other side (here, the upper side) of the axial direction K. The second end 65B is located on the side of the second opening 63B. Among the through holes 65H, on the side of the first end 65A, it is formed in a tapered shape in which the inner diameter increases as it goes downward (that is, as it moves away from the second end 65B).

[0030] As shown in FIG. 7, the spindle motor 66 is housed in the housing 63. The spindle motor 66 is disposed between the second bearing 64B and the third bearing 64C. The spindle motor 66 includes a rotor 66A and a stator 66B. The rotor 66A is integrally provided on the main shaft 65. The stator 66B is disposed at a position facing the rotor 66A. When current flows through the stator 66B, the main shaft 65 rotates at high speed. The spindle motor 66 is controlled by the control device 48.

[0031] As shown in FIG. 7, the collet chuck 67 extends in the vertical direction. The collet chuck 67 is inserted into the through hole 65H of the main shaft 65. The collet chuck 67 is configured to be movable in the axial direction K. The collet chuck 67 has a third end 67A and a fourth end 67B. The third end 67A is located on the first end 65A side (here, the lower side) of the main shaft 65. The third end 67A is configured to be able to grip either the machining tool 6A or the detection tool 6B. A part of the third end 67A protrudes outside from the through hole 65H of the main shaft 65. The fourth end 67B is located on the second end 65B side (here, the upper side) of the main shaft 65. The fourth end 67B is located within the through hole 65H of the main shaft 65.

[0032] As shown in FIG. 7, the drawbar 68 extends in the vertical direction. The drawbar 68 is inserted into the through hole 65H of the main shaft 65. The drawbar 68 is configured to be movable in the axial direction K. The drawbar 68 is disposed above the collet chuck 67. The drawbar 68 has a fifth end portion 68A and a sixth end portion 68B. The fifth end portion 68A is located on the side of the first end portion 65A (here, the lower side) of the main shaft 65. The fifth end portion 68A is connected to the fourth end portion 67B of the collet chuck 67. The fifth end portion 68A is located within the through hole 65H of the main shaft 65. The sixth end portion 68B is located on the side of the second end portion 65B (here, the upper side) of the main shaft 65. The sixth end portion 68B protrudes outside from the through hole 65H of the main shaft 65. The sixth end portion 68B is pressed by a push rod (not shown) of the actuator 61 (see FIG. 3). The drawbar 68 has a protruding piece 69. The drawbar 68 is prevented from moving in the first direction K1, for example, when the protruding piece 69 contacts a holding member 69B such as a nut. The first direction K1 is the direction from the first end portion 65A to the second end portion 65B of the main shaft 65.

[0033] As shown in FIG. 7, the biasing member 70 is provided around the drawbar 68. The biasing member 70 is supported by a third fixing member 78 attached to the main shaft 65. The biasing member 70 is, for example, a plurality of disc springs. The drawbar 68 is inserted through the biasing member 70. The biasing member 70 contacts the drawbar 68 and biases the drawbar 68 in the first direction K1. Here, the biasing member 70 contacts the protruding piece 69 of the drawbar 68 and biases the drawbar 68 in the first direction K1.

[0034] As shown in FIG. 7, the stopper 71 is disposed on the side of the biasing member 70. The stopper 71 is disposed around the biasing member 70. The stopper 71 is provided so as to be capable of contacting the protruding piece 69 of the drawbar 68. The stopper 71 limits the movement of the drawbar 68 in the second direction K2 that exceeds a predetermined amount when the stopper 71 contacts the protruding piece 69 of the drawbar 68. The second direction K2 is the direction from the second end portion 65B to the first end portion 65A of the main shaft 65.

[0035] As shown in FIG. 8, the first fixing member 74 is fixed to the main shaft 65. The first fixing member 74 is housed in the housing 63. The first fixing member 74 holds the first bearing 64A and the second bearing 64B from below. More specifically, the first fixing member 74 holds the inner ring 64AA of the first bearing 64A from below. The first fixing member 74 restricts the axial movement of the first bearing 64A and the second bearing 64B in the axial direction K. The first fixing member 74 is formed in a ring shape. The first fixing member 74 is, for example, a nut.

[0036] As shown in FIG. 8, the second fixing member 76 is fixed to the housing 63. The second fixing member 76 is housed in the housing 63. The second fixing member 76 is located outside the first fixing member 74. A gap is formed between the second fixing member 76 and the first fixing member 74. The second fixing member 76 holds the first bearing 64A and the second bearing 64B from below. More specifically, the second fixing member 76 holds the outer ring 64AB of the first bearing 64A from below. The second fixing member 76 restricts the axial movement of the first bearing 64A and the second bearing 64B in the axial direction K. As shown in FIG. 10, the second fixing member 76 is formed in a ring shape. The second fixing member 76 has a first portion 76A that presses the first bearing 64A from below, a second portion 76B that is fixed to the housing 63, and an opening 76C. The first portion 76A includes an upper surface 76AA that contacts the outer ring 64AB of the first bearing 64A and an inclined surface 76AB that extends obliquely downward from the upper surface 76AA. A recess 76AH that is recessed downward from the upper surface 76AA and the inclined surface 76AB is formed in the first portion 76A. In the present embodiment, four recesses 76AH are formed. The recesses 76AH communicate with the through holes 63CH (see FIG. 8) of the housing 63, respectively.

[0037] As shown in FIG. 7, the third fixing member 78 is fixed to the main shaft 65. The third fixing member 78 is fixed to the second end portion 65B of the main shaft 65. The third fixing member 78 restricts the axial movement of the third bearing 64C in the axial direction K. The third fixing member 78 holds the biasing member 70 and the stopper 71. The third fixing member 78 is, for example, a nut.

[0038] As shown in FIG. 7, the cover member 72 is a member that covers the first opening 63A of the housing 63. The cover member 72 is a part of the housing 63. The cover member 72 is formed of, for example, a resin material (e.g., polyacetal resin). As shown in FIG. 13, the cover member 72 is formed in a disk shape. A through hole 72H (also see FIG. 13) through which the main shaft 65 is inserted is formed in the cover member 72. The diameter of the through hole 72H is larger than the diameter of the main shaft 65. The cover member 72 is arranged at a distance from the main shaft 65. That is, a gap is provided between the main shaft 65 and the cover member 72, and the cover member 72 does not rotate even when the main shaft 65 rotates. The cover member 72 is arranged at a distance from the first fixing member 74. The cover member 72 is in contact with the second fixing member 76. Note that the cover member 72 may be arranged at a distance from the second fixing member 76.

[0039] As shown in FIG. 8, the air discharge port 96 is formed in the housing 63. More specifically, the air discharge port 96 is formed between the portion of the cover member 72 where the through hole 72H is formed and the main shaft 65. The air discharge port 96 opens downward along the axial direction K of the main shaft 65. The air discharge port 96 is located below the first bearing 64A. The air discharge port 96 is located above the lower end 83B of a nozzle 83 (see FIG. 7) described later. As will be described later, the air discharge port 96 discharges the air in the housing 63 to the outside of the housing 63. More specifically, the air discharge port 96 discharges the air flowing below the first bearing 64A to the outside of the housing 63.

[0040] As shown in FIG. 7, the coolant housing 80 is attached to the housing 63. The coolant housing 80 is formed in a cylindrical shape. The coolant housing 80 includes a supply port 81 to which a coolant liquid is supplied, a flow passage 82 through which the coolant liquid flows, and a nozzle 83 (also see FIG. 12) that discharges the coolant liquid toward the processing tool 6A. The supply port 81 is connected to a storage tank 37 (see FIG. 3) provided in the case body 12 via a liquid supply passage (for example, a resin tube that is easily deformable) (not shown). The coolant liquid stored in the storage tank 37 is supplied to the supply port 81 by driving a pump 85 (see FIG. 11) provided in the case body 12. That is, by driving the pump 85, the coolant liquid is discharged from the nozzle 83 toward the processing tool 6A as shown by the arrow L1 in FIG. 7. The pump 85 is controlled by the control device 48. The flow passage 82 communicates the supply port 81 and the nozzle 83. The nozzle 83 is located outside the air discharge port 96. The nozzle 83 opens toward the processing tool 6A. The coolant liquid discharged from the nozzle 83 toward the processing tool 6A returns to the storage tank 37 through the internal space 26. Note that FIG. 8 shows a state in which the coolant housing 80 is removed.

[0041] As shown in FIG. 7, in the radial direction P of the main shaft 65, the distance LA between the axis 65P of the main shaft 65 and the air discharge port 96 is shorter than the distance LB between the air discharge port 96 and the nozzle 83. In the radial direction P of the main shaft 65, the lower end 83B of the nozzle 83 is located inside the outer edge 72Q of the cover member 72. That is, in the radial direction P of the main shaft 65, the distance between the axis 65P of the main shaft 65 and the outer edge 72Q of the cover member 72 is longer than the distance between the axis 65P and the lower end 83B of the nozzle 83.

[0042] As shown in FIG. 7, the air inlet 90 is formed in the housing 63. The air inlet 90 introduces air into the housing 63. The air inlet 90 is disposed above the first bearing 64A. The air inlet 90 is disposed above the third bearing 64C. The air inlet 90 is connected to a compressor 98 (see FIG. 11) provided outside the case body 12 via a gas supply passage (for example, a deformable resin tube) not shown. The compressor 98 is controlled by the control device 48. The compressor 98 supplies compressed air into the housing 63 through the air inlet 90. The air compressed by the compressor 98 may have a pressure of generally 0.1 MPa or more, for example, 0.2 ± 0.05 MkPa.

[0043] As shown in FIG. 8, the air flow path 94 is formed in the housing 63 so as to flow the air introduced from the air inlet 90 (see FIG. 7) to the through hole 72H (i.e., the air outlet 96) of the cover member 72. More specifically, the air flow path 94 is formed in the housing 63 so that the air introduced from the air inlet 90 flows below the first bearing 64A. The air flow path 94 includes a first portion 94A, a second portion 94B, and a third portion 94C. The first portion 94A is located below the first bearing 64A. The first portion 94A is defined by the first bearing 64A and a recess 76AH provided in the second fixing member 76. The air flowing through the first portion 94A passes through the surface of the first bearing 64A. The first portion 94A communicates with a through hole 63CH formed in the first bearing holding portion 63C. The second portion 94B is located laterally of the first fixing member 74. Here, the second portion 94B is located outside the first fixing member 74. The second portion 94B is located above the air outlet 96. The second portion 94B is defined by the first fixing member 74 and the second fixing member 76. That is, the second portion 94B is formed in the gap between the first fixing member 74 and the second fixing member 76. The second portion 94B communicates with the first portion 94A. The third portion 94C is located below the first fixing member 74. The third portion 94C is defined by the first fixing member 74 and the cover member 72. That is, the third portion 94C is formed in the gap between the first fixing member 74 and the cover member 72. The third portion 94C communicates with the second portion 94B and the air outlet 96.

[0044] Next, the air flow inside the housing 63 will be described. As shown by the arrow F1 in FIG. 7, by driving the compressor 98 (see FIG. 11), compressed air is supplied into the housing 63 through the air inlet 90. The air supplied into the housing 63 from the air inlet 90 passes through the through-hole 63DH formed in the second bearing holder 63D and flows toward the spindle motor 66. The compressed air passes between the rotor 66A and the stator 66B and flows into the through-hole 63CH formed in the first bearing holder 63C. Then, as shown by the arrow F2 in FIG. 8, the compressed air flowing into the through-hole 63CH flows into the second portion 94B through the first portion 94A of the air flow path 94. At this time, since the compressed air passes below (typically directly below) the first bearing 64A, the periphery of the first bearing 64A becomes a positive pressure. Then, the compressed air flowing into the second portion 94B is discharged to the outside of the housing 63 through the third portion 94C and the air outlet 96.

[0045] As described above, the main shaft 65 is inserted through the through-hole 72H formed in the cover member 72, and the main shaft 65 and the cover member 72 are arranged to be separated from each other. That is, since a gap (here, the air outlet 96) is formed on the side of the main shaft 65, the cover member 72 does not rotate even when the main shaft 65 rotates. For this reason, even when the area of the cover member 72 is relatively large, the cutting powder attached to the cover member 72 is not affected by the centrifugal force due to the rotation of the main shaft 65 and does not move. Thus, by providing a gap on the side of the main shaft 65, it is possible to reduce the cutting powder adhering to the gap.

[0046] The spindle 62 of this embodiment is formed in the housing 63 and is located above the first bearing 64A, and has an air inlet 90 for introducing air into the housing 63, an air flow path 94 formed in the housing 63 for flowing the air introduced from the air inlet 90 to the through-hole 72H, and is located between the portion of the cover member 72 where the through-hole 72H is formed and the main shaft 65, and has an air outlet 96 for discharging the air in the housing 63 to the outside of the housing 63. The air flow path 94 formed in the housing 63 is configured to flow the air introduced from the air inlet 90 to the through-hole 72H. Then, the air in the housing 63 is discharged to the outside of the housing 63 through the air outlet 96. Thereby, the air flow path 94 can be kept at a positive pressure. That is, since the air outside the housing 63 does not flow into the air flow path 94 through the air outlet 96, the cutting powder generated when machining the workpiece 5 using the machining tool 6A is also suppressed from entering the air outlet 96.

[0047] In the spindle 62 of this embodiment, the air outlet 96 opens downward along the axial direction K of the main shaft 65. When the air outlet 96 opens downward along the axial direction K of the main shaft 65, the structure may be such that cutting powder easily enters the air outlet 96. However, since the air flow path 94 is kept at a positive pressure, air can be surely discharged from the air outlet 96, and it is possible to suppress the cutting powder from scattering toward the air outlet 96.

[0048] The spindle 62 of this embodiment is located outside the air outlet 96 and is provided with a nozzle 83 that discharges coolant liquid toward the machining tool 6A. When using coolant liquid, the cutting powder of the workpiece 5 is mixed in the coolant liquid, and the cutting powder together with the coolant liquid scatters toward the air outlet 96. However, since the air flow path 94 is kept at a positive pressure, air is surely discharged from the air outlet 96, and it is possible to suppress the cutting powder and the coolant liquid from scattering toward the air outlet 96. Also, regarding the radial direction P of the spindle 65, the distance LA between the axis 65P of the spindle 65 and the air outlet 96 is shorter than the distance LB between the air outlet 96 and the nozzle 83. Thereby, the amount of cutting powder scattered toward the air outlet 96 can be reduced.

[0049] In the spindle 62 of this embodiment, the air outlet 96 is located above the lower end 83B of the nozzle 83. Thereby, the amount of coolant liquid scattered toward the air outlet 96 can be reduced.

[0050] In the spindle 62 of this embodiment, regarding the radial direction P of the spindle 65, the lower end 83B of the nozzle 83 is located inside the outer edge 72Q of the cover member 72. Thereby, the amount of coolant liquid scattered toward the air outlet 96 can be reduced.

[0051] As described above, the preferred embodiments of the present invention have been described. However, each of the above-described embodiments is merely an example, and the present invention can be implemented in various other forms.

[0052] In the above-described embodiment, the through-hole 63CH was provided outside the first bearing 64A and the second bearing 64B, but it is not limited to this. The through-hole 63CH may be provided inside the first bearing 64A and the second bearing 64B. In this case, the through-hole 63CH is formed, for example, in the spindle 65. Then, by providing a recess similar to the recess 76AH in the first fixing member 74, it is possible to allow the air introduced from the air inlet 90 to flow below the first bearing 64A.

[0053] In the above-described embodiment, the lower end 83B of the nozzle 83 is located below the first end portion 65A of the main shaft 65, but it may be located above. Further, the lower end 83B of the nozzle 83 may be located outside the outer edge 72Q of the cover member 72.

Explanation of Signs

[0054] 5 Workpiece 6A Processing tool 10 Cutting device 62 Spindle 63 Housing 63A First opening 64A First bearing (bearing) 65 Main shaft 65H Through hole 67 Collet chuck 68 Drawbar 72 Cover member 80 Coolant housing 83 Nozzle 90 Air inlet 94 Air flow path 96 Air outlet

Claims

1. A housing having a first opening and a second opening, a bearing housed in the housing, a main shaft rotatably supported by the bearing, having a first through-hole formed therethrough in the axial direction, located on one side in the axial direction and on the first opening side, extending from the first opening to the outside of the housing, having a first end, and located on the other side in the axial direction and on the second opening side, having a second end, a collet chuck located on the first end side of the main shaft, having a third end capable of gripping a machining tool for machining a workpiece, and a fourth end located on the second end side of the main shaft, inserted into the first through-hole and configured to be movable in the axial direction, a drawbar located on the first end side of the main shaft, having a fifth end connected to the fourth end of the collet chuck, and a sixth end located on the second end side of the main shaft, inserted into the first through-hole and configured to be movable in the axial direction, a cover member covering the first opening and having a second through-hole through which the main shaft is inserted, a fixing member fixed to the main shaft and holding the bearing from below, an air inlet formed in the housing and located above the bearing, for introducing air into the housing, an air flow path formed in the housing, for flowing the air introduced from the air inlet to the second through-hole, comprising: the main shaft and the cover member are arranged to be separated from each other, the air flow path includes a portion partitioned by the fixing member and the cover member, an air discharge port is provided between a portion of the cover member where the second through-hole is formed and the main shaft, for discharging the air in the housing to the outside of the housing, the cover member covers the fixing member from below. Spindle.

2. The air discharge port of the spindle according to claim 1, which opens downward along the axial direction of the main shaft.

3. a nozzle located outside the air discharge port and discharging a coolant liquid toward the machining tool, In the radial direction of the main shaft, the distance between the axis of the main shaft and the air discharge port is shorter than the distance between the air discharge port and the point located closest to the axis of the main shaft in the nozzle. The spindle according to claim 1 or 2.

4. The air discharge port of the spindle according to claim 3, which is located above the lower end of the nozzle.

5. The spindle according to claim 3 or 4, wherein the lower end of the nozzle is located inside the outer edge of the cover member with respect to the radial direction of the main spindle.

6. A spindle according to any one of claims 1 to 5, a unit moving device that moves the spindle in a predetermined direction, a tool magazine capable of accommodating the machining tool, a cutting device comprising a holding member that is connected to the tool magazine and holds the workpiece to be machined by the machining tool.

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