Tool spindle unit and machine tool

Abstract

To provide a tool spindle unit configured so that the amount of coolants remaining therein can be reduced more than before.SOLUTION: A tool spindle unit comprises a tool spindle base 13, a tool headstock 11 which is supported rotatably on the tool spindle base 13 to process a work-piece using a tool unit 70 mounted on the tip thereof, a flow passage for coolants and a flow passage for air. The coolants and the air flow through individual flow passages respectively up to a confluent portion 51b provided inside the tool headstock 11 and then flow through a common flow passage 55a to side closer to a downstream than the confluent portion 51b. The flow passage for air extending up to the confluent portion 51b has a flow passage extending from the side of the tool headstock to the confluent portion 51b, through which air is flowed into the tool headstock 11.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a tool spindle unit and a machine tool. [Background technology]

[0002] 2. Description of the Related Art As a tool spindle unit provided in a machine tool, one having a function of discharging coolant and air from a tip end thereof, as disclosed in Patent Document 1, for example, is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2015-47669 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional machine tool such as the tool spindle unit of Patent Document 1, as shown in FIG. 10, a coolant flow path 220 connected to a coolant supply unit 280 and an air flow path 230 connected to an air supply unit 290 join at a joining portion 240 outside the tool spindle unit 210, and thereafter, the coolant and air are discharged through the same flow path 250. When the machining of the workpiece by the tool unit 270 is completed, the supply of coolant discharged from the tool unit 270 is stopped. Then, the tool unit 270 is removed for tool replacement, and at that time, air is blown from a blowing nozzle 257 provided at the tip of the tool spindle unit 210 to remove deposits on the tool unit 270 and the tapered hole 216. However, a large amount of coolant remains over a long section from the joining portion 240 to the blowing nozzle 257, and there is a problem that it takes time to discharge the coolant before the air is blown.

[0005] The present invention has been made in light of these problems, and has an object to provide a tool spindle unit and a machine tool that can reduce the amount of coolant remaining inside compared to conventional methods. [Means for solving the problem]

[0006] In order to achieve the above object, the tool spindle unit of the present invention includes a tool spindle stock, a spindle rotatably supported on the tool spindle stock and for machining a workpiece with a tool unit attached to its tip, a coolant flow path, and an air flow path, wherein the coolant and air flow through independent flow paths up to a joining point provided inside the spindle and flow through a common flow path downstream of the joining point, and the air flow path up to the joining point has a flow path extending from the side of the spindle to the joining point, allowing air to flow into the spindle.

[0007] In order to achieve the above object, a machine tool according to the present invention includes the above-described tool spindle unit that machines the workpiece with the tool unit attached thereto. Effect of the Invention

[0008] According to the present invention, it is possible to provide a tool spindle unit and a machine tool that can reduce the amount of coolant remaining inside compared to conventional methods. [Brief description of the drawings]

[0009] [Figure 1] 1 is a front view of a machine tool according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of the machine tool as viewed from an arrow II in FIG. [Diagram 3] 3 is a partial cross-sectional view showing an unclamped state of the machine tool as viewed from the arrow III in FIG. 1. [Figure 4] FIG. 4 is a partially enlarged view of the machine tool showing a portion “IV” in FIG. 3 . [Diagram 5] FIG. 5 is a partially enlarged view of the machine tool showing an enlarged portion of the “V” in FIG. 4. [Figure 6]6(a) is a partially enlarged view of the machine tool showing the "VIa" portion in FIG. 4, and (b) is a view showing the state in which the machine tool in (a) has clamped a tool unit. [Figure 7] FIG. 2 is a partial cross-sectional view showing a clamped state of the machine tool according to the embodiment of the present invention. [Figure 8] FIG. 8 is a partial cross-sectional view of the machine tool shown in FIG. 7 in an unclamped state. [Figure 9] 5A and 5B are diagrams showing the relationship between an air supply port and an unclamped shaft of a machine tool according to an embodiment of the present invention, where (a) is a partial cross-sectional view seen from the same direction as in FIG. 3 when the machine tool is in a clamped state, (b) is a partial cross-sectional view seen from the same direction as in FIG. 3 when the machine tool is in an unclamped state and no air is being supplied, (c) is a partial cross-sectional view seen from the arrow c in (b), and (d) is a partial cross-sectional view when air is being supplied from the state shown in (c). [Figure 10] FIG. 1 is a side view of a tool spindle of a conventional machine tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a tool spindle unit and a machine tool according to an embodiment of the present invention will be described with reference to the drawings. In the following description, as shown in Fig. 1, a direction parallel to the rotation axis of the spindle 11 is defined as the Z axis, and directions perpendicular to the Z axis direction are defined as the X axis direction and the Y axis direction. In other words, the Z axis direction coincides with the height direction, and the X axis direction and the Y axis direction are directions perpendicular to each other in the horizontal direction.

[0011] First, an overview of the machine tool 1 will be described with reference to Figs. 1 and 2. The machine tool 1 is a vertical machining center in which the rotation axis of the spindle 11 is parallel to the Z axis. As shown in Figs. 1 and 2, the machine tool 1 includes a bed S which is a base for the entire machine tool 1, a table 20 to which a workpiece W is fixed, a tool spindle unit 10 which processes the workpiece W with an attached tool unit 70a (70), a tool magazine 30 which stores multiple types of tool units 70 which can be replaced with the tool unit 70a of the tool spindle unit 10, an automatic tool changer 40 which changes the tool unit 70 attached to the tool spindle unit 10, and a control unit 300 which controls the overall operation of the machine tool 1. Among the multiple tool units 70 described below, the tool unit 70 attached to the tool spindle unit 10 will be referred to as tool unit 70a in order to distinguish it from the other tool units 70. 7, the tool unit 70 has the tool 12, a tool holder 72 that holds the tool 12, and a pull stud 71 provided at the rear end of the tool holder 72. The tool 12 is, for example, a drill, but may be another tool.

[0012] As shown in FIG. 1, the tool spindle unit 10 includes a tool spindle stock 13 that houses various components of the tool spindle unit 10, a spindle 11 that is rotatably mounted on the tool spindle stock 13 around a rotation axis, and a motor 14 that is mounted on the upper end of the tool spindle stock 13 and rotates the spindle 11. As shown in FIG. 3, a plurality of bearings 15 are provided inside the tool spindle stock 13, and the hollow spindle 11 parallel to the Z axis is rotatably supported by the plurality of bearings 15. The spindle 11 is provided with various mechanisms for detachably mounting the tool unit 70a at its tip, and with supply paths for supplying coolant and air. In addition, a tapered hole 16 is formed at the tip of the spindle 11, into which a tapered tool holder 72 can be inserted, as shown in FIG. 4. As shown in FIG. 1, the tool spindle unit 10 holds the tool unit 70a at its tip and processes the workpiece W fixed to the table 20 with a tool 12. The tool spindle unit 10 is provided so as to be movable in the Z-axis direction by a Z-axis movement mechanism 10Z shown in Fig. 2. The Z-axis movement mechanism 10Z has a motor 10Za and a ball screw and a nut (not shown), and converts the rotational force of the motor 10Za into linear motion by the ball screw and the nut, thereby linearly moving the tool spindle unit 10 in the Z-axis direction.

[0013] The table 20 has a flat plate portion 21 extending in the XY plane. A workpiece W is fixed to the flat plate portion 21 via a jig 22. The table 20 is provided on a bed S via a Y-axis moving mechanism 20Y shown in Fig. 2 and an X-axis moving mechanism 20X shown in Fig. 1.

[0014] The Y-axis moving mechanism 20Y moves the X-axis moving mechanism 20X and the table 20 shown in FIG. 1 in the Y-axis direction. The X-axis moving mechanism 20X moves the table 20 in the X-axis direction. The X-axis moving mechanism 20X has a motor 20Xa, a ball screw 20Xb, and a nut 20Xc, and converts the rotational force of the motor 20Xa into linear motion by the ball screw 20Xb and the nut 20Xc. The Y-axis moving mechanism 20Y has a motor 20Ya, a ball screw 20Yb, and a nut 20Yc, and converts the rotational force of the motor 20Ya into linear motion by the ball screw 20Yb and the nut 20Yc. As a result, the table 20 moves in the X-axis direction and the Y-axis direction.

[0015] The tool magazine 30 is provided on the left side of the tool spindle unit 10 in FIG. 1. As shown in FIG. 2, the tool magazine 30 has a substantially circular shape and is supported rotatably around a rotation axis parallel to the X-axis. The tool magazine 30 has a plurality of tool holding parts 31 in the circumferential direction. Each tool holding part 31 holds a tool unit 70 to be replaced with the tool unit 70a attached to the tool spindle unit 10. In this embodiment, 20 replacement tool units 70 are attached to the tool magazine 30 with their tips facing outward. The tool magazine 30 rotates around a rotation axis parallel to the X-axis, and moves a new tool unit 70b to be attached to the tool spindle unit 10 to the bottom end. The tool magazine 30 rotates the tool holding part 31 located at the bottom end by 90 degrees around the Y-axis, as shown by the arrow Y1 in FIG. 1. As a result, the tip of the tool 12 of the tool unit 70b faces downward, and preparations for transferring the tool unit 70b to the automatic tool changer 40 are completed. In this manner, among the multiple tool units 70 held in the tool magazine 30, the tool unit 70 that has been moved to the lower end to be handed over to the automatic tool changer 40 is referred to as tool unit 70b.

[0016] The automatic tool changer 40 is a device for changing a tool unit 70, called an ATC (Automatic Tool Changer). The automatic tool changer 40 is provided between the tool spindle unit 10 and the tool magazine 30, as shown in FIG. 1. The automatic tool changer 40 has a flat arm 41, as shown in FIG. 2. The arm 41 has a first gripping portion 41a for gripping a tool unit 70a attached to the tool spindle unit 10, and a second gripping portion 41b for gripping a tool unit 70b held in the tool magazine 30. The tool unit 70 is gripped by fitting a groove portion 72b of a tool holder 72 into the first gripping portion 41a and the second gripping portion 41b. The arm 41 can rotate about a rotation axis 41c (Z-axis direction) and move in the up-down direction (Z-axis direction) by a drive mechanism (not shown).

[0017] The control unit 300 includes, for example, a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) that stores a program that defines the procedure of processing by the CPU, and the like.

[0018] 1 and 2, the machine tool 1 has a coolant supply unit 100 that supplies coolant, and an air supply unit 200 that supplies air. The coolant supply unit 100 is connected to a coolant pump (not shown), and the coolant supplied from the coolant supply unit 100 passes through the inside of the tool spindle unit 10 and is discharged from the tip of the spindle 11. The air supply unit 200 is connected to an air pressure source, and the air supplied from the air supply unit 200 also passes through the inside of the tool spindle unit 10 and is discharged from the tip of the spindle 11.

[0019] Next, the tool spindle unit 10 which forms the supply paths for coolant and air will be described in detail.

[0020] 3, the coolant sent out from the coolant supply unit 100 passes through coolant piping 42 extending from the coolant supply unit 100 and is supplied to a rotary joint 43 provided inside the tool spindle unit 10 via a joint case 84. The coolant supplied to the rotary joint 43 passes through the motor 44 and flows downward toward the spindle 11.

[0021] The rotary joint 43 connects the coolant pipe 42 and a motor rotating shaft 45 of the motor 44. The rotary joint 43 supplies coolant from the fixed coolant pipe 42 to the motor rotating shaft 45, which is a rotating body.

[0022] The motor 44 has a motor shaft 45 that rotates the main shaft 11 about an axis parallel to the Z axis. The motor shaft 45 extends in the Z axis direction and has a flow passage 45a formed therein for passing a coolant. The lower end of the motor shaft 45 and the main shaft 11 are connected via a coupling 46.

[0023] 5, a guide pipe 47 is attached to the tip of the motor rotating shaft 45. The guide pipe 47 has a first guide pipe 48 provided on the upper side and a second guide pipe 49 provided on the lower side.

[0024] The first guide pipe 48 has a protruding portion 48b that protrudes upward. A male thread is formed on the outer peripheral surface of the protruding portion 48b, and the male thread is fastened to a female thread formed on the inner peripheral surface of the flow passage 45a of the motor rotating shaft 45. The first guide pipe 48 is formed with a flow passage 48a that penetrates in the vertical direction and communicates with the flow passage 45a.

[0025] The second guide pipe 49 is a substantially cylindrical member, and is fastened to the first guide pipe 48 by a bolt (not shown) with one end inserted into the hollow portion of the main shaft 11. The second guide pipe 49 is formed with a protruding portion 49b that protrudes upward and is inserted into the flow path 48a of the first guide pipe 48. The second guide pipe 49 is also formed with a flow path 49a that penetrates in the vertical direction and communicates with the flow path 48a.

[0026] In this manner, the guide pipe 47 having the first guide pipe 48 and the second guide pipe 49 allows the coolant to flow from the flow passage 45a of the motor rotating shaft 45 into the main shaft 11 through the flow passages 48a and 49a.

[0027] Also, a check valve 50 is provided in the flow path 49a of the second guide pipe 49 to restrict the flow of coolant to the forward direction (downward) and prevent backflow. The check valve 50 does not open unless a certain pressure or more is applied even when it receives a forward flow, so it does not allow the coolant to pass when the supply of coolant from the coolant supply unit 100 stops. Since the guide pipe 47 is divided into two parts, the first guide pipe 48 and the second guide pipe 49, the check valve 50 can be easily installed inside the guide pipe 47. Also, since the check valve 50 can be installed in a position close to the spindle 11, the amount of residual coolant can be reduced.

[0028] The slide pipe 51 is a pipe member whose upper portion is inserted into the flow passage 49a of the second guide pipe 49. As a result, the slide pipe 51 is guided in the up-down direction by the second guide pipe 49. The slide pipe 51 is provided in a state in which it penetrates the unclamping shaft 52 (described later) that extends in the horizontal direction from the height direction (Z-axis direction). An air inlet hole 51a is formed in the middle portion of the slide pipe 51 to allow air to flow into the flow passage 51c from the side. The coolant that has passed through the second guide pipe 49 from the upper portion flows into the flow passage 51c of the slide pipe 51. In addition, air flows into the flow passage 51c of the slide pipe 51 from the air inlet hole 51a provided in the middle portion. In this way, a junction 51b where the coolant flow passage and the air flow passage join is formed in the middle portion of the flow passage 51c of the slide pipe 51. The slide pipe 51 supplies the coolant that flows in from above and the air that flows in from the air inlet hole 51a to the draw bar 55. The slide pipe 51 is formed with a male thread and is fastened to a draw bar 55 which is formed with a female thread.

[0029] 3, the air sent out from the air supply unit 200 flows into an air pipe 60 extending from the air supply unit 200. The air pipe 60 is connected to a block 61 fixed to the unclamping lever 150.

[0030] As shown in Fig. 7, the unclamping lever 150 is L-shaped and has a rotation shaft 151 at a bent portion. The unclamping lever 150 is supported by the tool headstock 13 so as to be rotatable about the rotation shaft 151 (X-axis). One end of the unclamping lever 150 is pushed by a hydraulic cylinder 81 as a drive source that moves linearly. Meanwhile, the other end of the unclamping lever 150 is in contact with the upper portion of the dog 53 as shown in Fig. 7. With one end of the unclamping lever 150 pushed by the hydraulic cylinder 81, the unclamping lever 150 rotates clockwise in Fig. 7 and functions as a transmission mechanism that pushes the dog 53 downward.

[0031] The block 61 moves in accordance with the movement of the unclamping lever 150. As shown in Fig. 5, an air supply port 62 is attached to the tip of the block 61. As shown in Fig. 9(c) and Fig. 9(d), the block 61 has a flange portion 61a with a bolt hole 61b formed therein.

[0032] As shown in Figs. 9(c) and 9(d), the air supply port 62 supplies the air supplied to the block 61 to the unclamping shaft 52. A bolt 64 is attached to the air supply port 62 through a bolt hole 61b. A spring 63 is interposed between the block 61 and a head 64a of the bolt 64, and when no air pressure is applied, the air supply port 62 is in close contact with the block 61 under the elastic force of the spring 63. The air supply port 62 advances while being guided by the bolt 64 under the air pressure of the air supplied to the block 61, while when the supply of air to the block 61 is stopped, the air supply port 62 retreats while being guided by the bolt 64 under the elastic force of the spring 63. In this way, the spring 63 has a spring constant that contracts under the action of air pressure. In addition, the air supply port 62 advances and retreats while being guided by the two bolts 64, so that inclination during advance and retreat is prevented.

[0033] As shown in FIG. 5, the unclamped shaft 52 is inserted into the main shaft 11 in a direction perpendicular to the axis (horizontal direction) as a main shaft insertion member. The unclamped shaft 52 is a cylindrical rod-like part that transmits the vertical movement of the dog 53 relative to the main shaft 11 to the joint 54, and is assembled in a state in which it penetrates the dog 53 and the joint 54. The unclamped shaft 52 moves vertically relative to the main shaft 11 together with the dog 53, the joint 54, and the slide pipe 51. The main shaft 11 is formed with an opening 11a that allows the unclamped shaft 52 to move vertically. The unclamped shaft 52 is also formed with an insertion hole 52b into which the slide pipe 51 is inserted in a direction perpendicular to the axis (Z-axis direction), and a flow path 52a for passing air is formed, which extends from one end in the axial direction (horizontal direction) and reaches the insertion hole 52b. The position of the air inlet hole 51a of the slide pipe 51 inserted into the insertion hole 52b matches the position of the flow path 52a. As a result, the air that has flowed into flow path 52a flows from the side of spindle 11 into the inside of spindle 11, passes through air inlet hole 51a, and flows into slide pipe 51. In this manner, air inlet hole 51a connects flow path 52a of unclamped shaft 52 and flow path 51c of slide pipe 51. Downstream of junction 51b where the coolant flow path and the air flow path join, the coolant and air pass through a common flow path.

[0034] A check valve 65 is provided in the flow path 52a of the unclamped shaft 52 to restrict the air flow to the forward direction (rightward in FIG. 5) and prevent backflow. The check valve 65 does not open unless a certain pressure or more is applied even if it receives a forward flow, so when the supply of air from the air supply unit 200 stops, it does not allow air to pass in either direction. The check valve 65 also prevents coolant from entering the air flow path.

[0035] The dog 53 is formed so as to surround the outer circumferential surface of the main shaft 11. When the dog 53 is pressed down by the unclamping lever 150, the dog 53 moves downward relative to the main shaft 11. The force pressing down the dog 53 is transmitted to the unclamping shaft 52 which passes through the dog 53.

[0036] The joint 54 is provided in the hollow portion of the spindle 11 so as to be movable up and down. The unclamped shaft 52 passes through the joint 54 in the horizontal direction, and the slide pipe 51 passes through the joint 54 in the vertical direction. An insertion hole 54a into which the upper part of the drawbar 55 is inserted is formed in the center of the lower surface of the joint 54. A female thread is formed in the insertion hole 54a, and the drawbar 55 having a male thread formed on the upper part is fastened to the insertion hole 54a. The joint 54 transmits the vertical movement of the unclamped shaft 52 to the drawbar 55 fastened to the insertion hole 54a. A disc spring 59 is arranged on the lower surface of the joint 54.

[0037] The disc springs 59 are stacked in the Z-axis direction and housed in the spindle 11 with the drawbar 55 inserted in the center hole. A spring receiver 59a is provided between the uppermost disc spring 59 and the underside of the joint 54. A spring receiver 59b is provided between the lowermost disc spring 59 and a step portion 11b that reduces the diameter of the hollow portion of the spindle 11 shown in Fig. 6(a). When the unclamping lever 150 is not pressing down on the dog 53 (when in the clamped state), the disc spring 59 holds the joint 54 in an upturned state by its elastic force.

[0038] As shown in FIG. 5, the drawbar 55 has a male screw formed on the top thereof, which is fastened to a female screw formed on the joint 54. As shown in FIG. 6(a), the drawbar 55 has a flow passage 55a, which penetrates vertically and has a diameter of, for example, 3.0 mm, a small diameter hole 55b which is a hole continuing below the flow passage 55a and has a larger diameter than the flow passage 55a, and a large diameter hole 55c which is a hole continuing below the small diameter hole 55b and has a larger diameter than the small diameter hole 55b. A female screw is formed in the large diameter hole 55c, and a male screw formed on the top of the collet attachment portion 56 is fastened to this female screw. In this way, the drawbar 55 transmits the vertical movement of the joint 54 to the collet attachment portion 56.

[0039] Collet mounting part 56 is a part for mounting spray nozzle 57 and collet 58 to draw bar 55. Collet mounting part 56 has a through hole having large diameter hole 56a and small diameter hole 56b that is continuous with the large diameter hole 56a below and has a smaller diameter than large diameter hole 56a. By connecting collet mounting part 56 and draw bar 55, large diameter hole 56a and small diameter hole 56b form a guide space 82 that guides spray nozzle 57 in the up and down direction.

[0040] The spray nozzle 57 is a tubular member having a flow passage 57a penetrating vertically. The spray nozzle 57 has a large diameter portion 57b having a large outer diameter in the center of the longitudinal direction, and small diameter portions 57c, 57d extending from both ends of the large diameter portion 57b. The large diameter portion 57b and the small diameter portion 57c extending from the upper end of the large diameter portion 57b are accommodated in a guide space 82. The small diameter portion 57d extending from the lower end of the large diameter portion 57b is inserted into the small diameter hole 56b of the collet attachment portion 56. The guide space 82 also accommodates a spring 83 interposed between the large diameter portion 57b of the spray nozzle 57 and the step portion 55d. This step portion 55d is formed at the boundary between the flow passage 55a of the draw bar 55 and the small diameter hole 55b. The spring 83 is accommodated in the guide space 82 in a compressed state, and pushes the spray nozzle 57 downward. The length of small diameter portion 57d of spray nozzle 57 is longer than the depth of small diameter hole 56b of collet attachment portion 56. Therefore, small diameter portion 57d inserted from one opening of small diameter hole 56b protrudes from the other opening of small diameter hole 56b.

[0041] In this manner, the flow passage 57a of the spray nozzle 57 housed between the connected draw bar 55 and collet attachment portion 56 is connected to the flow passage 55a of the draw bar 55. Therefore, the coolant and air from the draw bar 55 flow into the flow passage 57a of the spray nozzle 57. As shown in FIG. 6(a), when the tool unit 70 is not clamped, air is discharged from the spray nozzle 57 and sprayed onto the tip of the spindle 11 and the tool unit 70, as described below. On the other hand, as shown in FIG. 6(b), when the tool unit is clamped, the spray nozzle 57 is pressed down by a spring 83, as described below, and is in close contact with the tool unit 70. The coolant discharged from the spray nozzle 57 passes through the flow passage 70c of the tool unit 70 and is discharged from the tool 12 (FIG. 7).

[0042] Collet 58 clamps or unclamps pull stud 71. Collet 58 moves up and down with the movement of collet attachment part 56, and by moving upwards it contracts in diameter, thereby clamping pull stud 71. On the other hand, by moving downwards it expands in diameter, unclamping pull stud 71. In other words, collet 58 expands and contracts with the up and down movement of drawbar 55 attached to collet attachment part 56, making it possible to attach and detach pull stud 71.

[0043] As shown in Figures 4 and 7, the pull stud 71 has a male thread at the bottom in the figure and is fastened to a tool holder 72 having a female thread. The tool holder 72 has a tapered shape toward one end and holds the tool 12. The tool holder 72 is formed with a groove portion 72b that fits into the first gripping portion 41a and the second gripping portion 41b of the arm 41. The pull stud 71, the tool holder 72, and the tool 12 are formed with flow paths 71a, 72a, and 12c for passing coolant and air, respectively. That is, the tool unit 70a is formed with a flow path 70c that penetrates the tool unit 70a.

[0044] The coolant discharged from the tool spindle unit having the above configuration first flows from the coolant supply unit 100 through the coolant pipe 42 into the tool spindle unit 10 as shown in FIG. 3. The coolant that flows into the tool spindle unit 10 passes through the rotary joint 43 and the motor 44, and is supplied from above into the inside of the spindle 11. The coolant that is supplied from above to the spindle 11 flows into the spray nozzle 57 through the guide pipe 47, the slide pipe 51, and the drawbar 55. When the tool spindle unit 10 clamps the tool unit 70, the spray nozzle 57 is brought into close contact with the tool unit 70 by the spring 83 as shown in FIG. 6(b). As a result, the flow path 57a of the spray nozzle 57 is connected to the flow path 70c of the tool unit 70. Therefore, the coolant that flows into the spray nozzle 57 flows into the tool unit 70 and is discharged from the tool 12.

[0045] On the other hand, air supplied from the air supply unit 200 flows into the block 61 from the air pipe 60 shown in FIG. 4. The air that flows into the block 61 advances the air supply port 62 and flows into the unclamped shaft 52 during unclamping, as shown in FIG. 9(c) and FIG. 9(d). The flow path 52a of the unclamped shaft 52 extends from the side of the spindle 11 to the junction 51b with the coolant, as shown in FIG. 5. Therefore, the air that flows into the unclamped shaft 52 passes through the air inlet hole 51a and flows into the junction 51b provided in the slide pipe 51. The air that flows into the slide pipe 51 then passes through the draw bar 55 and is discharged from the spray nozzle 57. In this way, the air that merges with the coolant flow path at the junction 51b passes through the same flow path as the coolant until it is discharged from the spray nozzle 57.

[0046] Here, a procedure for the tool spindle unit 10 to unclamp the tool unit 70a will be specifically described. As shown in Fig. 7, when the tool spindle unit 10 is in a state in which it has clamped the tool unit 70a, the collet 58 is pulled up by the drawbar 55 due to the elastic force of the disc spring 59 and is in an upper position. At this time, the unclamped shaft 52 is also in a state in which it is pushed up by the disc spring 59 via the joint 54. At this time, as shown in Figs. 7 and 9(a), there is a misalignment of the central axis between the air supply port 62 facing diagonally upward and the unclamped shaft 52 facing horizontally, and the air supply port 62 and the flow path 52a of the unclamped shaft 52 are not connected.

[0047] The control unit 300 operates the hydraulic cylinder 81 while the arm 41 grips the tool unit 70a, and pushes out one end of the unclamping lever 150 in the Y-axis direction as indicated by the arrow Y2, as shown in Fig. 7. This causes the unclamping lever 150 to rotate clockwise in the figure around the rotation shaft 151 as indicated by the arrow Y3.

[0048] In this manner, the other end of the unclamping lever 150 rotating clockwise pushes down (in the direction indicated by the arrow Y4) the dog 53, which has been pushed up by the elastic force of the disc spring 59. Then, the unclamping shaft 52 and the joint 54 assembled to the dog 53 move down, causing the drawbar 55 to move down.

[0049] Then, collet 58 is lowered via collet attachment portion 56 connected to the lower end of draw bar 55, whereby collet 58 expands in diameter as shown in FIG. 8, and unclamps tool unit 70a.

[0050] Next, a description will be given of an example of a procedure for replacing the tool unit 70a after the tool unit 70a attached to the tool spindle unit 10 has completed machining of the workpiece W. This replacement process is executed by the control unit 300 according to a program created in advance.

[0051] When machining by tool unit 70a attached to tool spindle unit 10 is completed, control unit 300 stops motor 44 to stop spindle 11 from rotating, and stops the supply of coolant from coolant supply unit 100. When spindle 11 stops rotating, control unit 300 determines the phase of spindle 11 so that the position of flow path 52a of unclamped shaft 52 matches the position of air supply port 62. In addition, since check valve 50 is provided in coolant flow path 49a as shown in FIG. 4, when the supply of coolant from coolant supply unit 100 stops, the flow of coolant into spindle 11 stops.

[0052] Next, the control unit 300 rotates the tool magazine 30 shown in Figures 1 and 2, and moves the tool unit 70b to be used in the next machining to the tool changing position. Specifically, as shown in Figure 1, the control unit 300 moves the tool unit 70b to be used in the next machining to the bottom end of the tool magazine 30, and rotates the tool unit 70b so that the tool 12 of the tool unit 70b faces downward as shown by the arrow Y1. As a result, the tool unit 70b moves to the tool changing position in the tool magazine 30. The process of moving the tool unit 70b to this tool changing position may be performed during machining of the workpiece W.

[0053] Next, the control unit 300 actuates the Z-axis movement mechanism 10Z to move the tool spindle unit 10 in the Z-axis direction to the tool changing position. As a result, the height position of the tool holder 72 of the tool unit 70a held by the tool spindle unit 10 coincides with the height position of the tool holder 72 of the tool unit 70b, as shown in FIG.

[0054] Next, the control unit 300 instructs a drive mechanism (not shown) to rotate the arm 41 counterclockwise in a plan view around the Z axis from the state shown in Fig. 2. As a result, the groove 72b of the tool unit 70a is fitted into the first gripping portion 41a shown in Fig. 7, and the groove 72b of the tool unit 70b is fitted into the second gripping portion 41b. As a result, the first gripping portion 41a of the arm 41 grips the tool unit 70a gripped by the tool spindle unit 10, and the second gripping portion 41b grips the tool unit 70b in the tool magazine 30.

[0055] Next, the control unit 300 actuates the hydraulic cylinder 81 to unclamp the tool unit 70 a held by the tool spindle unit 10 .

[0056] 8 and 9(b), the central axes of the air supply port 62 and the unclamped shaft 52 are aligned and connected when the hydraulic cylinder 81 is operated to rotate the unclamped lever 150. On the other hand, when air is not supplied from the air supply port 62 during clamping, a gap is generated between the air supply port 62 and the unclamped shaft 52, and the air supply port 62 and the flow path 52a of the unclamped shaft 52 are not connected.

[0057] Next, the control unit 300 lowers the arm 41 of the automatic tool changer 40. This lowering operation of the arm 41 is performed almost simultaneously with the operation of unclamping the tool unit 70a. As a result, the tool unit 70a is pulled out from the tool spindle unit 10, and the tool unit 70b is pulled out from the tool magazine 30.

[0058] When the arm 41 is lowered in this manner, the control unit 300 supplies air from the air supply unit 200 through the air pipe 60. The air that has passed through the air pipe 60 is supplied to the block 61. Then, as shown in FIG. 9(d), the air supply port 62 advances by receiving the air pressure of the air supplied to the block 61. This connects the air supply port 62 to the flow path 52a of the unclamped shaft 52, and air flows into the unclamped shaft 52. The air that has flowed into the unclamped shaft 52 flows into the spindle 11, passes through the slide pipe 51 and the draw bar 55, and is sprayed from the spray nozzle 57. At this time, the coolant that exists between the check valve 50 and the tip of the spray nozzle 57 is discharged as residual coolant. In addition, air can be sprayed onto the tapered hole 16, the pull stud 71, and the tool holder 72 formed at the tip of the spindle 11 during tool replacement, and the intrusion of chips and the like can be prevented while removing any attached matter. The air may be continuously supplied until the replacement of the tool unit 70 is completed, or the supply may be stopped during the replacement of the tool unit 70. The supply of air from the air supply unit 200 may be executed by unclamping the tool unit 70a.

[0059] Next, the control unit 300 rotates the arm 41 of the automatic tool changer 40 by 180 degrees clockwise about the Z axis in a plan view, thereby swapping the positions of the tool unit 70a and the tool unit 70b.

[0060] Next, the control unit 300 raises the arm 41 of the automatic tool changer 40. This allows the tool unit 70b to be inserted into the tool spindle unit 10, and the tool unit 70a to be inserted into the tool magazine 30. When inserting the tool unit 70b to be used in the next machining, air may be blown from the blow nozzle 57. This allows any deposits on the shank of the tool unit 70b to be removed.

[0061] When the insertion of the tool unit 70a and the tool unit 70b is completed, if the air supply from the air supply unit 200 is still continuing, the control unit 300 stops the air supply from the air supply unit 200. As a result, the air pressure flowing into the block 61 disappears, and the air supply port 62 retracts due to the restoring force of the spring 63. As a result, as shown in Figures 9(b) and 9(c), the air supply port 62 and the flow path 52a of the unclamping shaft 52 return to a disconnected state.

[0062] Next, the control unit 300 stops the operation of the hydraulic cylinder 81 and clamps the tool unit 70b to be used in the next machining operation to the tool spindle unit 10.

[0063] When the control unit 300 stops the operation of the hydraulic cylinder 81, the force pressing the dog 53 downward via the unclamping lever 150 is no longer applied. Therefore, the compressed disc spring 59 provided in the main shaft 11 expands, causing the joint 54, the unclamping shaft 52, etc. to rise, and the drawbar 55 is pulled up.

[0064] When collet 58 is raised via collet attachment portion 56 connected to the lower end of draw bar 55, collet 58 contracts in diameter and clamps tool unit 70b.

[0065] (effect) According to the embodiment described above, the following effects are achieved. (1) In the above embodiment, tool spindle unit 10 includes tool headstock 13 and spindle 11 that is rotatably supported by tool headstock 13 and machines workpiece W with tool unit 70 attached to its tip. A coolant flow path and an air flow path are provided inside spindle 11, and coolant and air flow through independent flow paths up to junction 51b provided inside spindle 11 and flow through a common flow path downstream of junction 51b. The air flow path up to junction 51b has a flow path extending from the side of spindle 11 to junction 51b, and allows air to flow into spindle 11. As a result, the flow path shared by the coolant and air can be from junction 51b to the tip of spray nozzle 57. On the other hand, in the conventional machine tool described with reference to Fig. 10, the coolant and air share a flow path over a long section from junction 240 on the outside of the tool spindle unit to spray nozzle 257. In this way, in tool spindle unit 10 according to the present embodiment, the amount of coolant discharged when air is blown can be reduced compared to the conventional case. In addition, the amount of coolant discharged can be reduced, so coolant does not splash when changing tools, and air can be used to remove adhesions and effectively prevent the intrusion of cutting chips, etc. This improves the tool gripping accuracy. Also, the start-up time before air is blown can be shortened, which shortens the processing time. In addition, the coolant flow path and the air flow path are common from the junction 51b in the main shaft 11 to the tip of the spray nozzle 57. Therefore, there is no need to provide a dedicated air flow path in the main shaft 11, the structure is simple, and the rigidity of the main shaft 11 is not reduced. In addition, the diameter of the main shaft 11 can be made small, enabling high-speed rotation.

[0066] (2) In the above embodiment, the tool spindle unit 10 further includes a spindle insertion member 52 having an air flow path extending to a junction 51b and inserted into the spindle 11 so as to intersect therewith, a pipe member 51 having an internal junction 51b and provided in a state of penetrating the spindle insertion member 52, and a drawbar 55 connected to the pipe member 51 and moving in the axial direction of the spindle 11 to operate a collet 58 to which the tool unit 70 can be attached and detached. An air inlet hole 51a is formed in the pipe member 51 to connect the internal flow path to the flow path of the spindle insertion member 52, and air flowing through the spindle insertion member 52 flows into the junction 51b through the air inlet hole 51a. This allows the coolant and air to join at the joining point 51b, thereby reducing the amount of residual coolant.

[0067] (3) In the above embodiment, tool spindle unit 10 further includes air supply port 62 which changes its state between a state in which the air can be supplied to a flow path provided inside spindle 11 and a state in which the air cannot be supplied to a flow path provided inside spindle 11. As a result, when the tool unit 70a is clamped, as shown in Fig. 7, air cannot be supplied between the air supply port 62 and the unclamped shaft 52 (the central axes of the air supply port 62 and the unclamped shaft 52 are misaligned, creating a gap between them). As a result, the air supply port 62 and the unclamped shaft 52 can be separated from each other when the spindle 11 rotates, allowing the spindle 11 to rotate at high speed. In addition, since the air supply port 62 and the unclamped shaft 52 do not come into contact with each other during rotation, they do not wear out, and this makes it possible to reduce maintenance costs and maintenance time.

[0068] (4) In the tool spindle unit 10 according to the above embodiment, the air supply port 62 moves toward and comes into contact with the spindle insertion member 52 upon receiving the air pressure when air is supplied. This allows the air supply port 62 and the spindle insertion member 52 to come into contact with each other and the air to be blown thereon simply by the air pressure when the air is supplied, and the mechanism for bringing the two into contact with each other can be simplified.

[0069] (5) In the above embodiment, the machine tool 1 includes a tool spindle unit according to any one of (1) to (4) above that machines a workpiece W with a tool unit attached thereto. This makes it possible to provide a machine tool which has the above-mentioned effects (1) to (4) and in which the amount of residual coolant in the tool spindle is small.

[0070] Further, the diameter of the flow passage 55a of the draw bar 55 is set to, for example, 3.0 mm, which is smaller than the diameter of a conventionally used draw bar. This reduces the volume of the flow passage 55a in the draw bar 55, making it possible to reduce the amount of coolant discharged when air is blown.

[0071] Furthermore, a check valve 50 is provided in coolant flow path 49a inside spindle 11, upstream of junction 51b, in flow path 49a of second guide pipe 49 to prevent coolant from flowing backward. Check valve 50 does not open unless a certain level of pressure is applied even when coolant flows in the forward direction, so that it is possible to prevent coolant from flowing into the inside of spindle 11 when the supply of coolant from coolant supply unit 100 stops. This makes it possible to reduce the amount of coolant discharged when blowing air.

[0072] Furthermore, a check valve 65 for preventing the intrusion of coolant is provided in air flow path 52a inside spindle 11, upstream of junction 51b, in flow path 52a of unclamped shaft 52. This makes it possible to prevent coolant from intruding into the air flow path.

[0073] Also, the elastic force of the spring 63 acts on the block 61 and the air supply port 62, and the air supply port 62 is advanced by air pressure only when air is being supplied, and is connected to the flow path 52a of the unclamping shaft 52. This makes it possible to simplify the structure by eliminating the need to provide a mechanism such as an air cylinder to advance and retract the air supply port 62. Also, since the air supply port 62 is advanced and retracted using the air pressure of the supplied air, a smooth connection is possible, and air can be instantly blown from the blowing nozzle 57.

[0074] This invention is not limited to the above embodiment, and various modifications and applications are possible. In the above embodiment, the coolant is introduced from above the spindle 11, and the air is introduced from the side of the spindle 11. However, the air may be introduced from above the spindle 11, and the coolant may be introduced from the side of the spindle 11.

[0075] Furthermore, the position where air is introduced into the main shaft 11 from the side, that is, the position where the unclamping shaft 52 is provided, is arbitrary, and it may be closer to the tip of the main shaft 11 or may be farther away.

[0076] The check valves 50, 65 provided in the coolant flow path and the air flow path are not limited to the above-described installation positions and may be installed at any positions. For example, they may be installed closer to the junction 51b, or may be installed in the piping outside the spindle 11 away from the junction 51b.

[0077] Also, although it has been described that the unclamping lever 150 rotates when pressed by the hydraulic cylinder 81, a mechanism using other power sources, such as an electric cylinder or a pneumatic cylinder, instead of hydraulic pressure, may be used.

[0078] Although the pressure of the coolant discharged from the tip of the spindle 11 is not specifically indicated, the coolant can be discharged at any pressure, from high pressure to low pressure.

[0079] Also, it has been described that air can be supplied from air supply port 62 to the inside of spindle 11 only when tool unit 70a is unclamped. However, air may be supplied even when tool unit 70a is clamped by configuring the air supply port 62 so that there is no misalignment between the air supply port 62 and the unclamped shaft 52. Also, a configuration may be adopted in which air can be supplied even when the spindle is rotating.

[0080] In addition, while the tool unit 70 is being replaced, air may be continuously supplied from the tip of the spindle 11, or the supply may be stopped halfway through the replacement of the tool unit 70, and the time and timing for supplying air are optional. For example, while the tool unit 70 is being replaced, air may be intermittently blown.

[0081] The diameter of the flow passage 55a of the draw bar 55 may be any size. For example, it may be larger than 3.0 mm, which is given as an example above. Also, it may be as small as possible within a range in which the required amount of coolant can be supplied.

[0082] In addition, the unclamped shaft 52 serving as the main shaft insertion member has been described as being rod-shaped, but as long as an air flow path is formed and it can be connected to the slide pipe 51, the shape may be arbitrary, and it may be in the form of a block.

[0083] Although the tool spindle unit 10 of this embodiment has been described as being applied to a vertical machining center as the machine tool 1, it can also be used appropriately in other machining centers such as a gate type machining center and a horizontal machining center. It can also be used appropriately in other machine tools such as a turning center and a lathe. [Explanation of symbols]

[0084] 1...machine tool, 10...tool spindle unit, 10Z...Z-axis movement mechanism, 11...spindle, 11a...opening, 11b...step, 12...tool, 12c...flow passage, 13...tool spindle stock, 14...motor, 15...bearing, 16...tapered hole, 20...table, 20X...X-axis movement mechanism, 20Xa...motor, 20Xb...ball screw, 20Xc...nut, 20Y...Y-axis movement mechanism, 20Ya...motor, 20Yb...ball screw, 20Yc...nut, 21...flat portion, 22...jig, 30...tool magazine, 31...tool holder, 40...automatic tool changer, 41...arm, 4 Reference Signs List 1a...first gripping portion, 41b...second gripping portion, 41c...rotating shaft, 42...coolant piping, 43...rotary joint, 44...motor, 45...motor rotating shaft, 45a...flow path, 46...coupling, 47...guide pipe, 48...first guide pipe, 48a...flow path, 48b...projection, 49...second guide pipe, 49a...flow path, 49b...projection, 50...check valve, 51...slide pipe (pipe member), 51a...air inlet hole, 51b...junction, 51c...flow path, 52...unclamped shaft (main shaft insertion member), 52a...flow path, 52b ...insertion hole, 53...dog, 54...joint, 54a...insertion hole, 55...draw bar, 55a...flow path, 55b...small diameter hole, 55c...large diameter hole, 55d...step, 56...collet attachment portion, 57...spray nozzle, 57a...flow path, 57b...large diameter portion, 57c, 57d...small diameter portion, 58...collet, 59...bell spring, 59a, 59b...spring support, 60...air piping, 61...block, 61a...flange portion, 61b...bolt hole, 62...air supply port, 63...spring, 64...bolt, 64a...bolt head, 65...check valve, 70, 70a, 70b...tool unit , 71...pull stud, 71a...flow passage, 72...tool holder, 72a...flow passage, 72b...groove, 81...hydraulic cylinder, 82...guide space, 83...spring, 84...joint case, 100...coolant supply section, 150...unclamp lever, 151...rotating shaft, 200...air supply section, 210...tool spindle unit, 216...tapered hole, 220, 230...flow passage, 240...junction, 250...flow passage, 257...spray nozzle, 270...tool unit, 280...coolant supply section, 290...air supply section, 300...control section, S...bed, W...work

Claims

1. A tool headstock; A spindle that is rotatably supported by the tool headstock and processes a workpiece using a tool unit attached to its tip; A coolant flow path; an air flow path; The coolant and the air flow through independent flow paths up to a joining point provided inside the spindle, and flow through a common flow path downstream of the joining point, The air flow path to the joining point has a flow path extending from a side of the main shaft to the joining point, and causes air to flow into the main shaft. Tool spindle unit.

2. a main shaft insertion member that is inserted into the main shaft so as to intersect with the main shaft and that has an air flow path extending to the joining point; A pipe member having the junction therein and penetrating the main shaft insertion member; a drawbar connected to the pipe member and moving in an axial direction of the spindle to operate a collet to which the tool unit can be attached and detached, The pipe member has an air inlet hole formed therein, the air inlet hole connecting a flow path formed therein to a flow path of the main shaft insertion member, The air flowing through the main shaft insertion member passes through the air inlet hole and flows into the joining point. The tool spindle unit according to claim 1.

3. and an air supply port that changes between a state in which the sent air can be supplied to a flow path provided inside the spindle and a state in which the sent air cannot be supplied to the flow path provided inside the spindle. The tool spindle unit according to claim 1.

4. The air supply port receives air pressure when supplying air and moves toward and contacts the spindle insertion member. The tool spindle unit according to claim 3.

5. The tool spindle unit according to any one of claims 1 to 4 is provided, which processes the workpiece by the attached tool unit. Machine tools.

Images