JP5861522B2 - Machine Tools - Google Patents

Description

  The present invention relates to a machine tool.

  A machine tool can selectively mount a turning tool and a turning tool on a common spindle, and can selectively perform turning and turning on a workpiece. Patent document 1 discloses the said machine tool. Rotation includes drilling and tapping, for example. Drilling, tapping, and the like are modes in which the main shaft rotates about the axis. Rotation is performed with the workpiece stationary. The turning process includes, for example, a facing process. Facing or the like is a mode in which the workpiece is turned relative to the main axis. Turning is performed with the spindle stopped. The spindle head includes an engaged portion with which an engaging portion of a tool for machining is engaged. The operator attaches a turning tool to the spindle. The engaged portion engages with the engaging portion. Since the spindle is mechanically locked, it cannot be rotated.

Japanese Patent No. 4543746

  The spindle cannot be rotated with a turning tool attached. Therefore, if the machine tool rotates the spindle with a turning tool mounted on the spindle, there is a possibility that an excessive load is applied to the spindle.

  An object of the present invention is to provide a machine tool capable of preventing an excessive load from being applied to a main shaft when the main shaft is rotated with a turning tool mounted on the main shaft.

A machine tool according to claim 1 of the present invention is a machine tool that selectively mounts a rotary machining tool and a machining tool on a common spindle, and selectively performs rotary machining and machining on a workpiece. The spindle head that rotatably holds the spindle and the spindle head are provided on the spindle head, and the rotation of the tool for machining is regulated based on the engagement of the engagement portion of the tool for machining. An engaged portion, a drive unit for driving the main shaft, a main shaft command determining means for determining whether there is a main shaft command for instructing rotation of the main shaft after turning on the power, and the main shaft command determining means are the main shaft If it is determined that there is a command, a drive output unit that outputs the spindle command to the drive unit, and whether the spindle has rotated within a predetermined time after the drive output unit outputs the spindle command to the drive unit Rotation determination means for determining whether or not the rotation determination means If it is determined that the spindle within the predetermined time does not rotate, a drive control means for stopping the drive unit, when the drive control means stops the drive unit, the spindle command is the spindle to the original position Orient command determining means for determining whether or not an orientation command is to be determined, and an abnormality notifying means for notifying an abnormality when the orientation command determining means determines that the spindle command is not the orientation command. And The spindle does not rotate with a tool for machining. After the power is turned on, if there is a spindle command due to a program error, for example, the drive output means outputs the spindle command to the drive unit. If the spindle does not rotate within a predetermined time, a turning tool is mounted. The drive control means stops the drive unit. Therefore, the machine tool can prevent an excessive load from being applied to the spindle when the spindle is accidentally rotated with a turning tool mounted on the spindle. If the spindle does not rotate within a predetermined time, there is a possibility of abnormality. The abnormality notification means notifies the abnormality when it is determined that the spindle command is not the orientation command. Therefore, the operator can promptly respond to the abnormality of the machine tool. The orientation command is a command for indexing the spindle to the origin position. Machine tools need to index the spindle to the origin position in order to properly attach and detach tools when changing tools. When a turning tool is mounted on the spindle, the position is already fixed at the origin position. Therefore, when the spindle command is an orientation command, the abnormality notifying means does not notify the abnormality. Therefore, the machine tool can proceed with processing.

  A machine tool according to a second aspect of the present invention is the machine tool according to the first aspect, wherein the drive unit is a servo motor, and the spindle command determination means determines that the spindle command is present. The servo motor is provided with current limiting means for limiting current. When a turning tool is mounted on the spindle, it cannot be rotated physically even if the servo motor is driven. The current flowing through the servo motor increases. The current limiting means provides a current limit. Therefore, the machine tool can prevent the servo motor from being overcurrent. The safety of machine tools is improved.

1 is a perspective view of a machine tool 1. 1 is a front view of a machine tool 1. The right view of the machine tool 1. FIG. The perspective view of tool T2. The perspective view which shows the state with which the tool T2 was mounted | worn with the main shaft 8. FIG. 1 is a block diagram showing an electrical configuration of a machine tool 1. FIG. The flowchart of a 1st NC control process. The flowchart of a 2nd NC control process.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, the diagonally lower left, diagonally upper right, diagonally lower right, and diagonally upper left are the front, rear, right, and left of the machine tool 1, respectively. The left-right direction, the front-rear direction, and the up-down direction of the machine tool 1 are defined as an X-axis direction, a Y-axis direction, and a Z-axis direction of the machine tool 1, respectively. A machine tool 1 shown in FIG. 1 is a combined processing machine. The multi-tasking machine can selectively perform rotation processing and machining processing on a workpiece (workpiece).

  The structure of the machine tool 1 will be described with reference to FIGS. The machine tool 1 includes a base 2, a Y-axis moving mechanism, a carrier 12, an X-axis moving mechanism, a column 5, a Z-axis moving mechanism, a spindle head 7, a spindle 8, a work holding device 80, an automatic tool changer (hereinafter referred to as a tool changer). 30) and the like.

  The base part 2 is a rectangular box-shaped iron member that is long in the Y-axis direction. The base 2 is provided with legs 3 at the lower four corners. The height of the leg 3 can be adjusted. The base part 2 includes a pedestal part 4, a right support part 18, and a left support part 19 on the upper surface. The pedestal 4 is provided on the rear side of the upper surface of the base 2. The pedestal portion 4 has a substantially rectangular parallelepiped shape, for example. The right support portion 18 and the left support portion 19 are pedestals having a height lower than that of the pedestal portion 4. The right support portion 18 is disposed on the right front side of the upper surface of the base portion 2. The left support portion 19 is disposed on the left front side of the upper surface of the base portion 2. The right support part 18 and the left support part 19 support the work holding device 80 from below.

  The Y-axis moving mechanism is provided on the upper surface of the base part 4. The Y-axis moving mechanism moves the transporter 12 in the Y-axis direction. The Y-axis moving mechanism includes a pair of Y-axis rails 61 and 62, a Y-axis ball screw 63, a Y-axis motor 52 (see FIG. 6), and the like. The Y-axis rails 61 and 62 are provided along the left and right ends of the upper surface of the pedestal 4. The Y-axis ball screw 63 is provided between the Y-axis rails 61 and 62. The transporter 12 is movable along the Y-axis rails 61 and 62. The carrier 12 is a metal plate member having a predetermined thickness, for example. The carrier 12 includes a nut (not shown) on the lower surface. The nut is screwed onto the Y-axis ball screw 63. The Y-axis motor 52 rotates the Y-axis ball screw 63. The carrier 12 moves in the Y-axis direction together with the nut.

  The X-axis moving mechanism is provided on the upper surface of the carrier 12. The X axis moving mechanism moves the column 5 in the X axis direction. The X-axis moving mechanism includes a pair of X-axis rails 71 and 72, an X-axis ball screw 73, an X-axis motor 51, and the like. The X-axis rails 71 and 72 and the X-axis ball screw 73 extend in the X-axis direction. The X-axis rail 71 is arranged on the rear side of the upper surface of the carrier 12 and the X-axis rail 72 is arranged on the front side of the upper surface of the carrier 12. The X-axis ball screw 73 is disposed between the X-axis rails 71 and 72. The column 5 is movable along the X-axis rails 71 and 72. The column 5 includes a nut (not shown) on the lower surface. The nut is screwed into the X-axis ball screw 73. The X-axis motor 51 rotates the X-axis ball screw 73. The column 5 moves in the X-axis direction together with the nut. The column 5 moves in the Y-axis direction via the carrier 12. That is, the column 5 can be moved in the X-axis direction and the Y-axis direction by the Y-axis moving mechanism, the X-axis moving mechanism, and the carrier 12.

  The column 5 includes a protective cover 16 at the lower right side, a protective cover 17 at the lower left side, and a cover 13 at the lower rear side. The protective cover 16 covers the X-axis moving mechanism exposed from the right side surface of the column 5 on the right side. The protective cover 17 covers the X-axis moving mechanism exposed on the left side from the left side surface of the column 5. The protective covers 16 and 17 move following the movement of the column 5 in the X-axis direction. The cover 13 covers the Y-axis moving mechanism exposed at the rear rear side of the column 5. The cover 13 expands and contracts following the movement of the column 5 in the Y-axis direction. The protective covers 16 and 17 and the cover 13 prevent chips and cutting fluid from entering the X-axis moving mechanism and the Y-axis moving mechanism.

  The Z-axis moving mechanism is provided on the front surface of the column 5. The Z-axis moving mechanism moves the spindle head 7 in the Z-axis direction. The Z-axis moving mechanism includes a pair of Z-axis rails (not shown), a Z-axis ball screw (not shown), a Z-axis motor 53 (see FIG. 6), and the like. The Z-axis rail and the Z-axis ball screw extend in the Z-axis direction. The Z-axis ball screw is disposed between a pair of Z-axis rails. The spindle head 7 is movable along the Z-axis rail. The spindle head 7 includes a nut (not shown) on the back surface. The nut is screwed onto the Z-axis ball screw. The Z-axis motor 53 rotates the Z-axis ball screw. The spindle head 7 moves in the Z-axis direction. The protective cover 28 is fixed to the upper rear side of the spindle head 7. The protective cover 28 moves up and down together with the spindle head 7 to cover the front surface of the column 5. The column 5 includes a Z-axis shutter 27 on the front surface. The Z-axis shutter 27 expands and contracts according to the vertical movement of the spindle head 7. The Z-axis shutter 27 prevents chips and cutting fluid from entering the Z-axis moving mechanism.

  The spindle head 7 moves up and down along the front surface of the column 5 by a Z-axis drive mechanism. The main shaft 8 is provided below the main shaft head 7. The main shaft 8 includes a tool mounting portion (not shown). The tool mounting portion is, for example, a tapered hole portion. The tool mounting portion mounts tools T1 and T2. The tool T1 is a rotary processing tool. The tool T2 is a turning tool. Hereinafter, the tools T1 and T2 are collectively referred to as a tool T. The spindle motor 54 is provided on the front side of the upper surface of the spindle head 7. The main shaft motor 54 rotates the main shaft 8. A cable bear (registered trademark) 29 is provided between the upper part of the spindle head 7 and the upper part of the column 5.

  The structure of the workpiece holding device 80 will be described with reference to FIGS. The work holding device 80 includes a right fixing part 88, a left fixing part 89, a jig fixing table 81, a C-axis motor 56, a C-axis 82, a tilt motor 57, and the like. The right fixing part 88 is fixed to the upper surface of the right support part 18. The left fixing part 89 is fixed to the upper surface of the left support part 19.

  The jig fixing table 81 includes a table portion 81A, a right connecting portion 81B, and a left connecting portion 81C. The C-axis motor 56 is provided on the lower surface side of the jig fixing table 81. The C-axis 82 is provided at substantially the center of the jig fixing table 81. The C axis 82 is cylindrical. The C shaft 82 is connected to the rotation shaft of the C axis motor 56. A jig (not shown) is fixed to the upper surface of the C-axis 82. The jig is, for example, cylindrical and is arranged coaxially with the C-axis 82. The jig holds the workpiece. The axial direction of the C-axis 82 is orthogonal to the surface of the table portion 81A. Therefore, the jig can be rotated together with the C-axis 82.

  The right connecting portion 81B extends from the table portion 81A in the upper right direction and is connected to the right fixing portion 88 so as to be rotatable around the X axis. The left connecting portion 81C extends from the table portion 81A in the upper left direction and is connected to the left fixing portion 89 so as to be rotatable around the X axis. The tilt motor 57 is fixed to the right fixing portion 88. The tilt motor 57 rotates the jig fixing table 81 around the X axis. The rotation shaft of the tilt motor 57 is connected to the right connecting portion 81B.

  The workpiece fixed to the jig is rotated around the axis of the C axis 82 by driving of the C axis motor 56. Regardless of the rotation of the jig fixing table 81 by the tilt motor 57, the workpiece fixed to the jig rotates about an axis perpendicular to the table portion 81A by driving the C-axis motor 56.

  The structure of the ATC 30 will be described with reference to FIGS. The ATC 30 includes a tool magazine 31, a magazine support member 32, a magazine motor 55, a drive gear 35, and the like. The magazine support member 32 is an elliptical metal plate member. The magazine support member 32 is attached to the column 5 with the spindle head 7 and the column 5 inserted inside. The tool magazine 31 is directed upward from the front to the rear.

  The tool magazine 31 is attached along the outer periphery of the magazine support member 32. The tool magazine 31 includes a chain 34 and a plurality of pots 37. The chain 34 is attached so as to be movable along the outer periphery of the magazine support member 32. The plurality of pots 37 are attached to the chain 34, respectively. The pot 37 can hold the tool T. The pot 37 is formed, for example, in an arm shape and is swingably attached.

  The magazine motor 55 is attached to the upper part of the magazine support member 32. The drive shaft of the magazine motor 55 is orthogonal to the upper surface of the magazine support member 32. The drive shaft of the magazine motor 55 can rotate in either forward or reverse direction. The drive gear 35 is attached to the drive shaft of the magazine motor 55. The drive gear 35 rotates with the drive shaft of the magazine motor 55. The drive gear 35 meshes with the chain 34 of the tool magazine 31. The chain 34 is moved in either the forward or reverse direction along the outer periphery of the magazine support member 32 by driving the drive gear 35. Therefore, the pot 37 moves along with the chain 34 along the outer periphery of the magazine support member 32. The position of the pot 37 located at the lowermost part of the tool magazine 31 is a tool change position. The tool change position is the position closest to the spindle 8. The ATC 30 replaces the next tool held by the pot 37 at the tool replacement position with the current tool mounted on the spindle 8.

  A processing method using the machine tool 1 will be described. The machine tool 1 is capable of rotating and turning. Rotational machining is a machining method that moves by applying a rotating tool T1 to a fixed workpiece. For example, it is used for drilling such as drills and taps. The rotary machining uses a rotary machining tool T1. The tool T1 can be rotated while being attached to the spindle 8. Turning is a machining method in which a tool T2 is applied to a rotating workpiece and moved. For example, it is used for facing processing. The turning process uses a turning tool T2. When the tool T2 is mounted on the main shaft 8, it cannot rotate.

  As shown in FIG. 4, the tool T2 includes a taper shank 101, a pull stud 102, a flange 103, and the like. The taper shank 101 is substantially conical. The taper shank 101 is mounted on a tool mounting portion (not shown) of the main shaft 8. The pull stud 102 is provided on the top of the taper shank 101. The pull stud 102 is a portion that is gripped by a gripping portion (not shown) provided in the tool mounting portion. The flange 103 is provided between the tool T2 and the taper shank 101. The flange 103 has a substantially disk shape extending outward in the radial direction of the tool T2.

  The flange 103 includes a pair of key grooves 105 and 106. The key grooves 105 and 106 are formed in a rectangular shape, but the shape is not limited. The key grooves 105 and 106 are at positions facing each other across the center of the flange 103. The key grooves 105 and 106 are unique to the turning tool T2. As shown in FIG. 5, the spindle head 7 includes a pair of keys 91 and 92 on the lower end surface. The keys 91 and 92 are, for example, convex. The shape of the keys 91 and 92 corresponds to the shape of the key grooves 105 and 106. The keys 91 and 92 are in a positional relationship facing each other across the tool mounting portion of the main shaft 8.

  As shown in FIG. 5, the spindle 8 (not shown in FIG. 5) is in a state where the tool T2 is mounted. The taper shank 101 of the tool T2 is mounted on the tool mounting portion of the main shaft 8. The flange 103 is in contact with the lower end surface of the spindle head 7. The keys 91 and 92 are engaged with the key grooves 105 and 106. The keys 91 and 92 are locked to the inner surfaces of the key grooves 105 and 106. Since the tool T2 is mechanically fixed to the spindle head 7, the spindle 8 cannot be rotated. Similar to the tool T2, the rotary machining tool T1 includes a tapered shank and a pull stud, but has no flange. Therefore, when the tool T1 is mounted on the tool mounting portion of the main shaft 8, it does not engage with the keys 91 and 92, so that the tool T1 can rotate with the main shaft 8.

  With reference to FIGS. 1-3, the rotary process using the machine tool 1 is demonstrated. The operator fixes the workpiece to the C-axis 82 using a jig. The ATC 30 mounts a rotary machining tool T1 on the spindle 8. The tool T1 is rotatable with respect to the spindle head 7. The machine tool 1 drives a spindle motor 54. The tool T1 rotates together with the main shaft 8. Since the machine tool 1 does not drive the C-axis motor 56, the workpiece fixed to the jig on the C-axis 82 does not rotate. The machine tool 1 can drive the X-axis motor 51 to the Z-axis motor 53 to move the position of the main shaft 8 and rotate the main shaft 8 to rotate the workpiece fixed to the jig.

  A turning process using the machine tool 1 will be described with reference to FIGS. The operator fixes the workpiece on the upper surface of the C-axis 82 using a jig. The ATC 30 mounts a turning tool T2 on the spindle 8. The tool T2 is in a state in which it cannot rotate with respect to the spindle head 7. The machine tool 1 drives a C-axis motor 56. The work fixed to the jig on the C-axis 82 rotates. The machine tool 1 drives the X-axis motor 51 to the Z-axis motor 53 to move the position of the spindle 8 and can turn the rotated workpiece with the tool T2.

  The machine tool 1 can adjust the workpiece posture around the X axis by a tilt motor 57. Therefore, a desired part of the workpiece can be processed. The machine tool 1 may process the workpiece by rotating the spindle motor 54 and the C-axis motor 56 simultaneously.

  The electrical configuration of the machine tool 1 will be described with reference to FIG. The machine tool 1 includes a numerical control unit 20. The numerical control unit 20 includes a CPU 21, a ROM 22, a RAM 23, a flash memory 24, an input unit 25, an input / output unit 26, and the like. The CPU 21 comprehensively controls the operation of the machine tool 1. The ROM 22 stores various programs. The RAM 23 stores various data. The flash memory 24 stores an NC program and the like. The NC program is composed of a plurality of blocks. Each block includes various NC commands. The NC command is a control command.

  The operation unit 38 and the Z-axis origin sensor 39 are connected to the input unit 25. The operation unit 38 is provided, for example, on a cover (not shown) that covers the machine tool 1. For example, the operation unit 38 is a device on which an operator performs various inputs and settings regarding the operation of the machine tool 1. The Z-axis origin sensor 39 detects the origin of the spindle head 7 in the Z-axis direction. The drive circuits 41 to 49 are connected to the input / output unit 26.

  The drive circuit 41 drives the X axis motor 51. The encoder 51A is connected to the X-axis motor 51 and the input / output unit 26. The encoder 51 </ b> A detects the rotation amount of the X-axis motor 51 and inputs the detection signal to the input / output unit 26. The drive circuit 42 drives the Y axis motor 52. The encoder 52 </ b> A is connected to the Y-axis motor 52 and the input / output unit 26. The encoder 52A detects the amount of rotation of the Y-axis motor 52 and inputs the detection signal to the input / output unit 26. The drive circuit 43 drives the Z-axis motor 53. The encoder 53A is connected to the Z-axis motor 53 and the input / output unit 26. The encoder 53 </ b> A detects the amount of rotation of the Z-axis motor 53 and inputs the detection signal to the input / output unit 26.

  The drive circuit 44 drives the spindle motor 54. The encoder 54 </ b> A is connected to the spindle motor 54 and the input / output unit 26. The encoder 54 </ b> A detects the amount of rotation of the spindle motor 54 and inputs the detection signal to the input / output unit 26. The drive circuit 45 drives the magazine motor 55. The encoder 55 </ b> A is connected to the magazine motor 55 and the input / output unit 26. The encoder 55 </ b> A detects the rotation amount of the magazine motor 55 and inputs the detection signal to the input / output unit 26. The drive circuit 46 drives the C-axis motor 56. The encoder 56 </ b> A is connected to the C-axis motor 56 and the input / output unit 26. The encoder 56 </ b> A detects the rotation amount of the C-axis motor 56 and inputs the detection signal to the input / output unit 26.

  The drive circuit 47 drives the tilt motor 57. The encoder 57 </ b> A is connected to the tilt motor 57 and the input / output unit 26. The encoder 57 </ b> A detects the amount of rotation of the tilt motor 57 and inputs the detection signal to the input / output unit 26. The drive circuit 48 drives the clamp device 58. The clamp device 58 is provided on the back side of the jig fixing table 81. The clamp device 58 fixes and holds the rotating shaft of the jig. The drive circuit 49 drives the display unit 11. The display unit 11 is provided, for example, on a cover (not shown). The display unit 11 displays various screens such as a setting screen and an operation screen of the machine tool 1.

  The X-axis motor 51, the Y-axis motor 52, the Z-axis motor 53, the main shaft motor 54, the magazine motor 55, the C-axis motor 56, and the tilt motor 57 are servo motors, for example.

  The first NC control process executed by the CPU 21 will be described with reference to FIG. After the power is turned on, the CPU 21 reads the first NC control program stored in the ROM 22 and executes this processing. First, the CPU 21 interprets one block of the NC program (S11). As a result of interpreting one block, the CPU 21 determines whether or not the control command is M30 (S12). M30 is an end command. If the CPU 21 determines that it is not M30 (S12: NO), it determines whether the control command is a spindle command (S13). When the CPU 21 determines that the command is not a spindle command (S13: NO), the CPU 21 performs an operation according to the interpreted control command (S24). Control commands other than the spindle command are, for example, an axis movement command, a positioning command, a tool change command, and the like. The CPU 21 returns to S11 and interprets the next block.

  When the CPU 21 determines that the command is a spindle command (S13: YES), the CPU 21 executes current limitation of the spindle motor 54 (S14). The CPU 21 executes a spindle command (S15). For example, when the rotary tool T1 is attached to the spindle 8, the tool T1 rotates. For example, when the turning tool T2 is attached to the spindle 8, the tool T2 does not rotate because it is in a non-rotatable state mechanically fixed to the spindle head 7. When the turning tool T2 is attached to the spindle 8, the tool T2 is mechanically fixed to the spindle head 7 as described above. For example, the CPU 21 outputs a spindle command to the spindle motor 54 while the tool T2 is mechanically fixed. The current flowing through the spindle motor 54 continuously increases and becomes overcurrent. The overcurrent places a load on the spindle motor 54 and causes a failure. This embodiment performs current limiting. For example, the current limit can control the drive circuit 44 so that a current exceeding a predetermined level does not flow through the spindle motor 54. Therefore, current control can prevent the spindle motor 54 from becoming overcurrent.

  The CPU 21 determines whether a predetermined time has elapsed after executing the spindle command (S16). Until the predetermined time has elapsed (S16: NO), the CPU 21 returns to S16 and enters a standby state. When the predetermined time has elapsed (S16: YES), the CPU 21 determines whether or not the spindle 8 has rotated a predetermined amount (S17). The rotation amount of the spindle 8 can be calculated from the rotation amount of the spindle motor 54 based on the detection signal from the encoder 54A. For example, when the main shaft 8 is rotated with the rotary tool T1 mounted on the main shaft 8, the main shaft 8 can rotate a predetermined amount in a predetermined time.

  When the CPU 21 determines that it has rotated by a predetermined amount (S17: YES), the spindle 8 is in a state in which a tool T1 for rotational machining is mounted. Therefore, the CPU 21 releases the current limit of the spindle motor 54 (S18) and continues the spindle command (S19). Thereafter, the CPU 21 determines whether or not the spindle command has been completed (S20). The CPU 21 returns to S20 and enters a standby state until the spindle command is completed (S20: NO). When the CPU 21 determines that the spindle command has been completed (S20: YES), the CPU 21 returns to S11 and repeats the above process in the same manner for the next block.

  When the CPU 21 determines that it has not rotated by a predetermined amount (S17: NO), the spindle 8 is in a state in which a turning tool T2 is mounted. The state in which the spindle command is output in a state where the tool T2 that does not rotate is mounted on the spindle 8 is caused by a program error, for example. If the machine tool 1 tries to rotate the spindle 8 with the tool T2 attached, an excessive load is applied to the spindle 8, causing a failure. The CPU 21 forcibly stops the spindle 8 (S21). Therefore, the machine tool 1 can prevent an excessive load from being applied to the spindle 8.

  The CPU 21 determines whether or not the spindle command is an orientation command (S22). The orientation command is a command for determining the spindle 8 at the origin position. The machine tool 1 needs to determine the spindle 8 at the origin position in order to normally attach and detach the tool T to and from the spindle 8 when changing the tool. When the turning tool T <b> 2 is attached to the main shaft 8, the keys 91 and 92 engage with the key grooves 105 and 106. Therefore, the position of the tool T2 with respect to the spindle head 7 is determined. The position of the tool T2 (the position of the spindle 8) is the origin position of the spindle 8. That is, the spindle 8 has already been determined at the origin position (orient state).

  When the CPU 21 determines that the spindle command is an orientation command (S22: YES), the CPU 21 releases the current limitation (S23). Thereafter, the CPU 21 returns the processing to S11 and repeats the above processing in the same manner for the next block.

If the CPU 21 determines that the spindle command is not an orientation command (S22: NO), it notifies a failure because there is a possibility of a program error or the like (S2 5 ), and ends this processing. The abnormality notification may be, for example, a process of displaying an abnormality message or the like on the display unit 11, a process of notifying by voice, or a process of lighting or blinking a lamp or the like. Therefore, since the operator can recognize the abnormality of the machine tool 1 at an early stage, a quick response is possible.

  CPU21 performs the said process similarly about the following block, and when a control command is M30 (S12: YES), this process is complete | finished.

In the above description, the CPU 21 that executes the process of S13 shown in the flowchart of FIG. 7 is an example of the spindle command determination means of the present invention. The CPU 21 that executes the process of S14 is an example of the current limiting means of the present invention. The CPU 21 that executes the process of S15 is an example of the drive output means of the present invention. The CPU 21 that executes the process of S17 is an example of the rotation determination means of the present invention. The CPU 21 that executes the process of S21 is an example of the drive control means of the present invention. The CPU 21 that executes the process of S22 is an example of the orientation command determination means of the present invention. CPU21 that performs the processing of S2 5 is an example of the abnormality notifying means of the present invention.

  As described above, the machine tool 1 according to the present embodiment can selectively attach the rotary machining tool T1 and the machining tool T2 to the common spindle 8. The machine tool 1 can selectively perform rotation processing and machining processing on a workpiece. The spindle head 7 includes a pair of keys 91 and 92 on the lower end surface. The tool T2 for machining includes a pair of key grooves 105 and 106. When the tool T2 for machining is mounted on the main shaft 8, the keys 91 and 92 engage with the key grooves 105 and 106 to restrict the rotation of the tool T2. The numerical control unit 20 of the machine tool 1 includes a CPU 21. After the power is turned on, the CPU 21 interprets the NC program block by block, and drives the spindle motor 54 when there is a spindle command. The CPU 21 determines whether or not the spindle 8 has rotated within a predetermined time after driving the spindle motor 54. The CPU 21 stops the spindle motor 54 when the spindle 8 does not rotate within a predetermined time. Therefore, the machine tool 1 can prevent an excessive load from being applied to the main shaft 8 when the main shaft 8 is erroneously rotated with the turning tool T2 attached to the main shaft 8. Further, for the tools T1 and T2, for example, it is not necessary to input information on whether or not rotation is possible, so that safety and convenience are improved.

  Particularly in the present embodiment, the spindle motor 54 is a servo motor. When the CPU 21 determines that there is a spindle command, it provides a current limit to the servo motor. Therefore, the machine tool 1 can prevent the servo motor from being overcurrent. The safety of the machine tool 1 is improved.

  Particularly in the present embodiment, when the CPU 21 determines that the spindle 8 has not rotated a predetermined amount within a predetermined time, for example, the display unit 11 notifies the abnormality. If the main shaft 8 does not rotate within a predetermined time, there is a possibility of abnormality. Since the CPU 21 notifies the abnormality, the operator can quickly cope with the abnormality of the machine tool 1.

  Particularly in the present embodiment, when the CPU 21 stops the spindle motor 54, it is determined whether or not the spindle command is an orientation command. The orientation command is a control command for determining the spindle 8 at the origin position. The machine tool 1 needs to determine the spindle 8 at the origin position in order to normally attach and detach the tool T when changing the tool. When the turning tool T2 is mounted, the spindle 8 is already fixed at the origin position. Therefore, when the spindle command is an orientation command, the CPU 21 does not notify the abnormality. Therefore, the machine tool 1 can proceed with processing.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above embodiment, the spindle motor 54 is current-limited, and the type of the tool T to be mounted on the spindle 8 is determined based on the rotation amount of the spindle 8. That is, in the above-described embodiment, it is determined from the amount of rotation of the main shaft 8 whether the main shaft 8 has rotated within a predetermined time. For example, the machine tool 1 may determine the type of the tool T to be mounted on the main spindle 8 based on the current value flowing through the main spindle motor 54 without limiting the current to the main spindle motor 54. The main shaft motor 54 is a servo motor. The modification uses the properties of the servo motor.

  CPU21 of the machine tool 1 which is a modification performs the 2nd NC control process shown in FIG. The second NC control process includes a process common to the first NC control process (see FIG. 7) of the above-described embodiment. The processes of S14, S18, and S23 are not performed, and the process of S31 is executed instead of the process of S17. To do. The processes of S14, S18, and S23 are processes related to current limitation. Since this modification uses the characteristics of the servo motor, the processes of S14, S18, and S23 are not executed.

  As shown in FIG. 8, for example, when the CPU 21 determines that the command is a spindle command (S13: YES), the spindle command is executed (S15). When the turning tool T2 is attached to the spindle 8, the tool T2 is mechanically fixed to the spindle head 7 as described above. Therefore, the main shaft 8 cannot rotate. For example, the CPU 21 outputs a spindle command to the spindle motor 54 with the tool T2 fixed to the spindle head 7. The current flowing through the spindle motor 54 continuously increases. When a predetermined time has elapsed since the execution of the spindle command (S16: YES), the CPU 21 determines whether or not the value of the current flowing through the spindle motor 54 is equal to or less than a predetermined value (S31).

  When the CPU 21 determines that the current value is equal to or less than the predetermined value (S31: YES), since the current flowing through the main shaft motor 54 has not increased, it can be determined that the main shaft 8 is mounted with the rotary machining tool T1. Therefore, the CPU 21 continues the spindle command (S19). When the CPU 21 determines that the current value exceeds the predetermined value (S31: NO), the current flowing through the spindle motor 54 continuously increases, so the spindle 8 is in a state in which a turning tool T2 is mounted. The CPU 21 stops driving the spindle 8 (S21). Therefore, this modification can determine whether or not the main shaft 8 has rotated within a predetermined time as in the above embodiment.

  In the above embodiment, after the spindle 8 is stopped (S21) in the process of FIG. 7, it is determined whether or not the spindle command is an orientation command (S22). However, the order of the processes in S21 and S22 may be reversed. .

  In the above embodiment, the presence or absence of rotation of the spindle 8 is determined based on whether or not it has rotated a predetermined amount within a predetermined time (S16, S17). For example, it is determined whether or not the spindle motor 54 has rotated. It may be.

DESCRIPTION OF SYMBOLS 1 Machine tool 7 Spindle head 8 Spindle 20 Numerical control part 21 CPU
54 Spindle motor 91, 92 Key 105, 106 Keyway T1 Tool T2 for turning Machining tool for turning

Claims (2)

A machine tool that selectively mounts a tool for rotation and a tool for machining on a common spindle, and selectively performs rotation and machining on a workpiece,
A spindle head for rotatably holding the spindle;
An engaged portion that is provided on the spindle head and restricts the rotation of the tool for machining based on the engagement of the engaging portion of the tool for machining;
A drive unit for driving the main shaft;
A spindle command determination means for determining whether or not there is a spindle command for instructing rotation of the spindle after turning on the power;
A drive output means for outputting the spindle command to the drive unit when the spindle command determining means determines that there is the spindle command;
Rotation determination means for determining whether or not the spindle has rotated within a predetermined time after the drive output means outputs the spindle command to the drive unit;
Drive control means for stopping the drive unit when the rotation determination means determines that the spindle has not rotated within the predetermined time ;
An orientation command determination means for determining whether the spindle command is an orientation command for determining the spindle at the origin position when the drive control means stops the drive unit;
A machine tool, comprising: an abnormality notifying means for notifying an abnormality when the orientation command determining means determines that the spindle command is not the orientation command . The drive unit is a servo motor,
The machine tool according to claim 1, further comprising a current limiting unit configured to limit a current to the servo motor when the spindle command determining unit determines that the spindle command is present.

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