JP6291750B2 - Machine tool and tool change method - Google Patents

Description

  The present invention relates to a machine tool and a tool exchange method for exchanging a tool stored in a storage unit and a tool mounted on a spindle for machining a workpiece.

  The machine tool includes a main shaft to which a tool is attached, a support portion that supports a workpiece and is rotatable about a vertical axis, and a tool magazine that stores a tool to be mounted on the main shaft. Tools are broadly classified into rotating tools that rotate on the spindle and non-rotating tools that are fixed on the spindle. When the rotating tool is mounted on the spindle, the workpiece does not rotate around the vertical axis, And is cut by the rotation of the main shaft. On the other hand, when the non-rotating tool is mounted on the main shaft, the non-rotating tool is fixed to the main shaft, and the workpiece rotates around the vertical axis at the support portion and is turned by the rotation of the support portion (see, for example, Patent Document 1). .

  The main shaft is provided with a key, and the rotary tool and the non-rotary tool are provided with a key groove to be engaged with the key. By engaging the key with the keyway, the rotating tool and the non-rotating tool are mounted on the main shaft. Patent Document 1 discloses a machine tool in which a protrusion is formed on a spindle head that covers the periphery of the spindle, and a groove that engages with the protrusion is formed in a non-rotating tool. The groove of the non-rotating tool is engaged with the protrusion, and the non-rotating tool is fixed on the main shaft and does not rotate about the main shaft.

Japanese Patent No. 4543746

  In the tool magazine, tools are stored in an orientation that assumes that the spindle is located at the origin. Therefore, before the tool change is executed, a process for positioning the spindle at the origin is executed. When the spindle is rotated to the origin position for tool replacement, feedback control is performed on a motor that rotates the spindle based on the difference between the origin position and the current position around the axis of the spindle. At this time, by calculating the accumulated value of the difference between the origin position and the current position and performing feedback control in consideration of the accumulated value, the rotation of the spindle to the origin position can be speeded up and highly accurate. .

  Such alignment of the spindle is also performed when a non-rotating tool is mounted on the spindle. When a non-rotating tool is mounted on the main shaft, the main shaft does not rotate, so it is expected that the main shaft will not change from the origin position. For this reason, it is expected that the spindle does not rotate even if alignment processing is performed on the spindle on which the non-rotating tool is mounted. However, in practice, the spindle on which the non-rotating tool is mounted may be fixed at a position slightly shifted from the origin position due to an error in the shape of the non-rotating tool or an error in the mounting operation of the non-rotating tool. In such a case, control is performed to rotate the main shaft to the origin position even though the main shaft is fixed so as not to rotate.

  If a non-rotating tool is mounted on the spindle and the process of rotating the spindle to the origin position is executed, the non-rotating tool does not rotate around the axis of the spindle, so an unnecessary load is applied to the motor that rotates the spindle. May be added. Furthermore, when feedback control is performed based on the accumulated value of the difference between the origin position and the current position of the spindle as described above, this deviation is accumulated even if there is a slight deviation from the origin position of the spindle due to the mounting of the non-rotating tool. Since the rotation of the motor is controlled, an excessive load may be applied to the motor. Further, when the non-rotating tool is removed from the main shaft while an excessive load is applied to the motor or the like, and the main shaft can be rotated, the main shaft may be rotated by the motor, and the position may be greatly deviated from the origin position.

  The present invention has been made in view of such circumstances, and the object of the present invention is to provide a motor that rotates the spindle even when tool replacement is performed when a non-rotating tool is mounted on the spindle. An object of the present invention is to provide a machine tool and a tool change method that can avoid an excessive load acting on the machine tool.

A machine tool according to the present invention includes a spindle that mounts a tool to process a workpiece, a storage unit that stores a tool that is mounted on the spindle, a tool that is mounted on the spindle, and a tool that is stored in the storage unit A first position control means for rotating the spindle to a specific position around the axis before exchanging the tool, and a control device that controls the exchange of the workpiece in the axial direction. In the machine tool having the second position control means for moving from the machining position to the change position for changing the tool, the control device calculates a value corresponding to the difference between the position of the spindle around the axis and the specific position. 1 calculation means, second calculation means for calculating a cumulative value of the values calculated by the first calculation means, and rotation control of the spindle based on the value calculated by the first calculation means by the first position control means. I do , Or, and a switching means for switching whether to perform rotation control of the spindle based on the cumulative value of the first value calculation means has calculated and the second calculating means is calculated, said switching means, said first When the position of the spindle moved by the two-position control means is from the machining position to a predetermined position between the machining position and the exchange position, the first position control means calculates the first calculation means. The rotation of the spindle based on the calculated value and the accumulated value calculated by the second calculation means, and the position of the spindle moved by the second position control means is from the predetermined position to the replacement position. The first position control means switches the control by the first position control means so as to perform rotation control of the spindle based on the value calculated by the first calculation means. .

  Further, in the machine tool according to the present invention, the switching unit calculates a value calculated by the first calculation unit and a cumulative value calculated by the second calculation unit before the tool is removed from the spindle for tool change. The control of the first position control unit is switched from the rotation control of the main shaft based on the rotation control to the rotation control of the main shaft based on the value calculated by the first calculation unit.

  In the machine tool according to the present invention, the main shaft can be mounted with a rotating tool that performs processing by rotating the main shaft or a non-rotating tool that performs processing without rotating, and is mounted on the main shaft. A tool determination unit that determines whether the tool is the rotating tool or the non-rotating tool, and the switching unit determines that the first position is determined when the tool determination unit determines that the tool is the rotating tool. When the control unit performs rotation control of the spindle based on the value calculated by the first calculation unit and the cumulative value calculated by the second calculation unit, and the tool determination unit determines that the tool is the non-rotating tool. The first position control means switches the control by the first position control means so as to perform rotation control of the spindle based on the value calculated by the first calculation means. .

Further, the tool replacement method according to the present invention replaces the tool mounted on the spindle and the tool stored in the storage unit, and rotates the spindle to a specific position around the axis before executing the tool replacement. And calculating a value corresponding to a difference between the position of the spindle around the axis and the specific position in a tool changing method for moving the spindle from a machining position on the workpiece in the axial direction to an exchange position for exchanging the tool. A calculation step, a second calculation step for calculating a cumulative value of the values calculated in the first calculation step, and a value calculated in the first calculation step when rotating the spindle to a specific position around the axis. The rotation control of the spindle is performed based on the value calculated in the first calculation step and the cumulative value calculated in the second calculation step. And a switching step of performing Kano switching, in the switching step, when the position of the main shaft to be moved in the axial direction is from the processing position to a predetermined position between said machining position and the replacement position, wherein Based on the value calculated in the first calculation step and the cumulative value calculated in the second calculation step, rotation control around the axis of the spindle is performed, and the position of the spindle moved in the axial direction is changed from the predetermined position to the predetermined position. The control is switched so as to perform rotation control of the spindle based on the value calculated in the first calculation step when the replacement position is reached .

  In the present invention, a value corresponding to the difference between the current position and the specific position of the spindle around the axis is calculated, and a cumulative value of this value is calculated. The specific position is, for example, the origin position of the spindle, and is the position where the spindle should be when changing tools. The machine tool switches between spindle rotation control based on a value corresponding to the difference and spindle rotation control based on a value corresponding to the difference and its accumulated value. As a result, the machine tool can switch the method of controlling the rotation of the spindle so as not to perform the rotation control of the spindle based on the accumulated value as necessary. That is, the machine tool can prevent an excessive load from being applied to the spindle on which the non-rotating tool is mounted by performing rotation control based on the accumulated value.

In the present invention, with respect to the axial direction of the spindle, the machine tool switches the rotation control of the spindle at a predetermined position between the machining position for the workpiece and the exchange position for changing the tool. The machine tool performs rotation control based on the value corresponding to the difference and the accumulated value from the machining position to the predetermined position, and performs rotation control based on the value corresponding to the difference from the predetermined position to the replacement position. The predetermined position is, for example, a position around the axis of the main spindle when alignment around the axis of the main spindle on which the rotary tool is mounted and movement of the main spindle in the axial direction from the machining position to the replacement position are performed simultaneously. A position where the alignment can be completed sufficiently can be set.
Thereby, the machine tool can perform high-speed and high-precision alignment by performing rotation control based on the accumulated value when aligning the spindle on which the rotary tool is mounted. The machine tool can switch the control method so as not to perform rotation control based on the accumulated value after the alignment of the spindle, and an excessive load based on the accumulated value is applied even if a non-rotating tool is mounted on the spindle. It does not join the spindle.
In addition, when switching control at a predetermined position, the machine tool may perform switching for the rotating tool and the non-rotating tool in the same way, so that the tool mounted on the spindle is a rotating tool or a non-rotating tool. There is an advantage that the machine tool does not need to determine which one of the two.

  Further, in the present invention, the machine tool performs rotation control based on the value corresponding to the difference from the rotation control based on the value corresponding to the difference and the accumulated value at least before the tool is removed from the spindle for tool change. Switch to. As a result, when the tool is removed, control based on the accumulated value is not performed. Therefore, when the non-rotating tool is removed for replacement, the spindle is identified by accumulating errors with respect to the specified position of the spindle position. It is possible to prevent rotation to a position greatly deviated from the position.

  In the present invention, the machine tool determines whether the tool mounted on the spindle is a rotating tool or a non-rotating tool. When the mounted tool is a rotary tool, the machine tool performs rotation control of the spindle based on the value according to the difference between the current position and the specific position and the accumulated value thereof, and aligns the spindle to the specific position. When the mounted tool is a non-rotating tool, the machine tool does not perform rotation control based on the accumulated value, but performs rotation control based on a value corresponding to the difference between the current position of the spindle and the specific position. Thereby, when a non-rotating tool is mounted on the spindle, it is possible to prevent an excessive load from being applied to the spindle by performing rotation control based on the accumulated value.

  The present invention is a configuration in which a machine tool switches whether or not to perform rotation control according to a difference between a current position of a spindle and a specific position. As a result, the machine tool can prevent an excessive load from being applied to the spindle on which the non-rotating tool is mounted.

It is a side view of a machine tool. It is a back side perspective view of the spindle head in the state where a tool is mounted. It is a front perspective view of the spindle head in a state where a tool is removed. It is a back side perspective view of the tool holder which concerns on a turning tool. It is a back side perspective view of an engaging projection part. It is a back side perspective view of the tool holder concerning a rotary tool. It is a block diagram which briefly shows the structure of a control apparatus. It is a schematic diagram for demonstrating the outline | summary of the rotation control of the main axis | shaft by a main shaft drive control part. It is a schematic diagram for demonstrating the switching control of whether to perform control using the cumulative value by a spindle drive control unit. It is a flowchart which shows the procedure of the tool exchange process by a control apparatus. It is a figure which shows an example of the process program memorize | stored in the memory | storage part. 10 is a flowchart showing a procedure of switching processing of spindle rotation control performed by a machine tool according to Modification 2;

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. In the following description, up and down, left and right, and front and rear indicated by arrows in the figure are used. 1 is a side view of the machine tool 100, FIG. 2 is a rear perspective view of the spindle head 3 with the tool 4 mounted thereon, and FIG. 3 is a front perspective view of the spindle head 3 with the tool 4 removed. FIG.

  The machine tool 100 arranges a Y-direction moving device (not shown) on the upper surface of the base 10 and supports the Y-direction moving table 11 so that the Y-direction moving device can move in the Y direction. The Y-direction moving device is connected to an output shaft of a Y-axis motor 72 (see FIG. 7 described later), extends in the front-rear direction (Y direction), a nut screwed to the feed screw shaft, and in the front-rear direction An extending guide rail.

  An X-direction moving device (not shown) is provided on the nut of the Y-direction moving device. The X-direction moving device is connected to an output shaft of an X-axis motor 71 (see FIG. 7 described later), extends in the left-right direction (X direction), a nut screwed to the feed screw shaft, and in the left-right direction An extending guide rail.

  The X-direction moving device supports the column 12 so as to be movable in the X direction. The column 12 has a columnar shape, and a Z-direction moving device (not shown) is provided on the front surface. The Z-direction moving device supports the spindle head 3 on the front side thereof so as to be movable in the Z direction. The Z-direction moving device is connected to an output shaft of a Z-axis motor 73 (see FIG. 7 to be described later), extends in the vertical direction (Z direction), a nut screwed to the feed screw shaft, and the column 12. A guide rail extending in the vertical direction is provided on the front surface, and a block fitted to the guide rail. The spindle head 3 is fixed to the nut and the block.

  The spindle head 3 is raised and lowered according to the rotation of the feed screw shaft driven by the Z-axis motor 73. Further, by driving the X-axis motor 71, the X-direction moving device moves left and right, and the spindle head 3 moves left and right. Further, the Y-direction moving device moves back and forth by driving the Y-axis motor 72, and the spindle head 3 moves back and forth.

  The machine tool 100 supports the workpiece (workpiece) by the workpiece support device 15 and processes the workpiece by the tool 4 attached to the spindle head 3. The work support device 15 has a work table 16 for clamping the work. The work support device 15 can rotate the work around two axes. In general, when a workpiece is rotated about axes parallel to the X, Y, and Z axes that are axes for moving the spindle head 3, the rotation axes of the workpiece correspond to the X, Y, and Z axes as A, B , Called the C-axis. The work support device 15 according to the present embodiment is provided with a work table 16 on a rocking body (not shown) that rocks around the A axis. The work table 16 is provided with an A-axis motor 61 (see FIG. 7 described later), and the swinging body swings around the A-axis by the rotation of the A-axis motor 61. The workpiece can be rotated about the A axis by the oscillation of the oscillator. A work table 16 is connected to an output shaft of a C-axis motor 60 fixed to the rocking body, and the work clamped on the work table 16 can be rotated at high speed around the C axis.

  The spindle head 3 supports a spindle 34 inside. The main shaft 34 is connected to a main shaft motor 31 fixed to the upper portion of the main shaft head 3, and rotates around the central axis in the vertical direction by driving the main shaft motor 31. The lower end portion of the main shaft 34 protrudes below the main shaft head 3 and holds the tool 4 to be mounted as will be described later. The tool 4 moves up and down with the spindle head 3.

  A plurality of tools 4 are stored in the tool magazine 2. The tool 4 includes not only rotating tools such as drills, taps, and end mills, but also turning tools (non-rotating tools) such as tools. The tool magazine 2 includes a support beam 21, a rail 22, a chain 23, a plurality of gripping arms 24, a magazine drive unit 25, and the like. The support beam 21 is a plate-like structural member having a triangular shape inclined downward with the upper side as a hypotenuse, and is fixed to the left and right of the column 12 in a cantilever manner. The support beam 21 extends from a portion fixed to the left and right of the column 12 to be inclined downward from both sides of the spindle head 3. The upper end surface of the support beam 21 is inclined by approximately 30 ° from the horizontal plane from the front lower side to the rear upper side.

  The rail 22 is an oval annular member, and is fixed to the support beam 21 so as to surround the column 12 and the spindle head 3. The chain 23 is configured by connecting endlessly a plurality of moving platforms having rollers that fit on the rail 22 and roll on the rail 22. A gripping arm 24 is attached to each moving table, and the gripping arm 24 grips a tool holder 40 that holds the tool 4. The chain 23 circulates along the rail 22 by the drive of the magazine drive unit 25. When exchanging tools, the chain 23 is circulated by driving the magazine drive unit 25, and the gripping arm 24 that grips the desired tool 4 is moved to the arm swinging position (the front lower end of the rail 22) below the spindle head 3. Be transported.

  The tool 4 is held by a known tool holder 40. The gripping arm 24 grips the tool 4 through the tool holder 40 by pushing the tip gripping portion 24 a branched into two into the holding groove 44 (see FIG. 4) on the outer periphery of the tool holder 40.

  In FIG. 1, the gripping arm 24 in the arm swinging position is in a posture of waiting after being separated from the main shaft 34 forward after the gripped tool 4 is mounted on the main shaft 34. The grip arm 24 has an arm shaft hole (not shown) into which the arm shaft is inserted at the upper end. The axial direction of the arm shaft is parallel to the X-axis direction when the gripping arm 24 is in the arm swing position, and the gripping arm 24 rotates around the arm axis, so that the tip gripping portion 24a approaches the main shaft 34 and separates. To do. A cam 32 extends vertically on the front side surface of the spindle head 3 so as to project forward. The grip arm 24 has a cam follower (not shown) that contacts the cam 32.

  The spindle head 3 descends from the origin position shown in FIG. 1 during machining, and rises from the origin position shown in FIG. 1 when changing tools. The gripping arm 24 in the arm swinging position swings as the spindle head 3 moves up and down. When the spindle head 3 is raised, the tip gripping portion 24a of the grip arm 24 approaches the spindle 34 and grips the tool holder 40 from the front. The spindle head 3 is further raised after the gripping of the tool holder 40 is completed. The tool holder 40 grasped by the grasping arm 24 moves relatively downward and is detached from the main shaft 34 together with the tool 4. The chain 23 rotates in this state, and the gripping arm 24 holding the tool 4 to be used next is conveyed to the arm swing position.

  The tool 4 is mounted on the spindle 34 when the spindle head 3 is lowered and the tool holder 40 is fitted into the lower end portion of the spindle 34. The tool 4 mounted on the spindle 34 is in the state shown in FIG. 1 when the spindle head 3 is lowered to the origin position, and stands by in preparation for machining.

  With the above operation, the tool 4 can be exchanged between the main spindle 34 and the tool magazine 2. The tool 4 mounted on the spindle 34 moves down from the origin position together with the spindle head 3 to process the workpiece clamped on the workpiece table 16.

  When the tool 4 is a rotary tool, the tool 4 attached to the main shaft 34 rotates with the main shaft 34 by driving the main shaft motor 31. The workpiece is positioned by rotating around the A axis and the C axis. The tool 4 that rotates together with the spindle 34 moves up and down, right and left, and back and forth together with the spindle head 3 to process the workpiece.

  When the tool 4 is a turning tool, the main shaft 34 is locked in a non-rotating state. When the work base 16 is rotationally driven by the C-axis motor 60, the work rotates. The tool 4 descends together with the spindle head 3, and turns the surface of the workpiece by pressing the tip against the rotating workpiece.

  FIG. 2 shows a state in which the turning tool 4 is mounted on the spindle 34. The tool holder 40 of the tool 4 includes a non-rotating flange 41 that protrudes rearward. On the lower surface of the spindle head 3 that supports the spindle 34, an engagement projection 5 that protrudes downward is provided at the rear position of the projection of the spindle 34. The tips of the pins 51 and 51 are projected. The anti-rotation flange 41 and the tip portions of the pins 51 and 51 are engaged with each other as shown in the figure by attaching the tool 4 to the main shaft 34, and the tool 4 is rotated around the central axis and by a force applied in the radial direction. It prevents the movement of the tool and acts so that turning with high machining accuracy can be performed stably.

  As shown in FIG. 2, the spindle head 3 has a bearing retainer 33 for holding a bearing for supporting the spindle 34 at the lower end. An air pipe 101 and a coolant pipe 102 are connected to the bearing retainer 33 at the rear. An air flow path through which air flows and a coolant flow path through which coolant liquid flows are formed inside the bearing retainer 33. The air prevents the cutting waste from entering the main shaft 34. The coolant (cleaning liquid) is used for cleaning the pins 51 and 51, a key 36 described later, and the like.

  FIG. 3 shows a state where the tool 4 is not mounted on the main shaft 34. The main shaft 34 is formed with a tapered hole 35 whose inner diameter increases downward at the lower end. The tool holder 40 is mounted on the main shaft 34 by fitting a tapered mounting portion 42 (see FIG. 4) formed on the upper portion thereof into the tapered hole 35. Two keys 36, 36 project from the peripheral edge of the lower end of the main shaft 34 in the radial direction and are fitted in a key groove (not shown) on the tool holder 40 side. A nozzle head 6 projects from the lower end surface of the bearing retainer 33. The nozzle head 6 injects coolant that cleans the engagement protrusions 51 and 51 and the like.

  Hereinafter, the structure of the rotation prevention flange 41 and the engagement protrusion part 5 is demonstrated. FIG. 4 is a rear perspective view of the tool holder 40 according to the turning tool, and FIG. 5 is a rear perspective view of the engaging protrusion 5.

  The anti-rotation flange 41 is formed by an annular substrate 41a, and an engaging plate 41b that is formed in a trapezoidal shape so as to protrude outward in the radial direction at about a half circumference of the outer periphery of the substrate 41a. The substrate 41 a is fixed to the lower surface of the tool holder 40 with a plurality of fixing bolts 45. The engagement plate 41b has engagement holes 43 and 43 formed on the two tops of the engagement plate 41b on the circumference that is coaxial with the tool holder 40, respectively. The illustrated engagement holes 43, 43 are elongated holes cut out on one side and open to the outer periphery of the engagement plate 41b. However, this opening is not essential, and is a long hole or a circular shape closed in the engagement plate 41b. It may be a hole.

  The engagement holes 43 and 43 are provided at positions where the center lines passing through the centers of the tool 4 and the tool holder 40 have an opening angle of about 90 ° on the side facing backward when mounted on the main shaft 34. In addition, the opening angle of the engagement holes 43 and 43 is not limited to 90 °, and can be set as appropriate within the range in which the rotation prevention flange 41 is formed. That is, the opening angle may be larger than 0 ° and smaller than 180 °, but is desirably 85 ° or larger and smaller than 100 °.

  The engaging protrusion 5 is integrally formed by a base 50, pins 51, 51 and the like. The base 50 includes support bases 50a and 50a and a connecting portion 50b. The support bases 50 a and 50 a have a columnar shape, and the upper end surface is in contact with the lower end surface of the spindle head 3. The connecting portion 50b has a plate shape and connects the side surfaces of the support bases 50a and 50a. A vertical through hole is provided at the upper end of the support bases 50a, 50a. The engaging protrusion 5 is fixed to the spindle head 3 by inserting a screw into the through hole and screwing it into a screw hole (not shown) provided on the lower end surface of the spindle head 3. Further, pin holes are formed in the upper end surfaces of the support bases 50a, 50a, and positioning pins are inserted into the pin holes and fitted into pin holes (not shown) provided in the lower end surface of the spindle head 3. Thus, the engaging protrusion 5 is positioned.

  The engaging projection 5 has a through hole 50c in a state of being attached to the lower end surface of the spindle head 3 (see FIG. 2). Pipes such as an air pipe 81 and a coolant pipe 82 connected to the spindle head 3 are inserted into the through hole 50c.

  The pins 51 and 51 protrude from the support bases 50a and 50a, and the tip portions protrude below the lower end surfaces of the support bases 50a and 50a. The protruding positions of the pins 51 and 51 are on a circumference that is coaxial with the main shaft 34 to which the tool holder 40 is mounted in order to enable engagement with the engagement holes 43 and 43 of the detent flange 41. Each is set on an opening line passing through the center of the main shaft 34 and having an opening angle of about 90 ° on the rear side.

  As shown in FIG. 2, the two engagement holes 43, 43 of the non-rotating flange 41 are engaged with the respective pins 51, 51, and the rotation with respect to the spindle head 3 to which the engagement protrusion 5 is attached is restricted. The Therefore, the tool holder 40 provided with the non-rotating flange 41 and the turning tool 4 held by the tool holder 40 are not rotated by a circumferential action force applied during machining. An electromagnetic brake (not shown) for stopping the rotation of the main shaft 34 is provided on the main shaft 34. When the turning tool 4 is mounted on the main shaft 34, the electromagnetic brake is operated, and the rotation of the main shaft 34 is also regulated by the electromagnetic brake.

  FIG. 6 is a rear perspective view of the tool holder according to the rotary tool. As shown in FIG. 6, the rotating tool (rotating tool 4) does not include the engagement plate 41b unlike the turning tool. Therefore, even if the rotary tool is mounted on the main shaft 34, the rotation of the main shaft 34 is not restricted by the pins 51 and 51, and the rotary tool rotates by the rotation of the main shaft 34. When the main shaft 34 rotates with the rotating tool mounted, the electromagnetic brake is released.

  FIG. 7 is a block diagram schematically showing the configuration of the control device. The machine tool 100 includes a control device 80, and the drive of the spindle head 3, the spindle 34, the tool magazine 2, the workpiece support device 15 and the like is controlled by the control device 80. The control device 80 includes a control unit 81, an X-axis drive control unit 82, a Y-axis drive control unit 83, a Z-axis drive control unit 84, a main shaft drive control unit 85, an A-axis drive control unit 86, and a C-axis drive control unit 87. Prepare. The control unit 81 includes a CPU 81a connected to each other via a bus, a RAM 81b that temporarily stores information, a rewritable storage unit 81c that stores a control program, an input / output interface (input / output I / F) 81d, A communication interface (communication I / F) 81e is provided. The RAM 81b has a register 81f (storage area). The control program has a plurality of instructions that are read sequentially.

  The CPU 81a reads the control program from the storage unit 81c to the RAM 81b and controls the machine tool. The control unit 81 temporarily stops various commands such as an X-axis drive control unit 82, a Y-axis drive control unit 83, a Z-axis drive control unit 84, and a main shaft drive control unit 85, for example, a drive command for driving the motor. Outputs a command. The X-axis drive control unit 82, the Y-axis drive control unit 83, the Z-axis drive control unit 84, and the main-axis drive control unit 85 indicate various notifications, for example, the completion of the motor drive and the completion of the motor pause. The notification is output to the control unit 81.

  The control unit 81 inputs / outputs signals to / from the operation panel 71b, the X-axis drive control unit 82, the Y-axis drive control unit 83, the Z-axis drive control unit 84, and the main shaft drive control unit 85 via the input / output I / F 81d. I do. The operation panel 71 b has a start switch, a temporary stop switch, and the like, and ON / OFF of the switch is input to the control unit 81. An image is displayed on the display unit of the operation panel 71b based on a display signal from the control unit 81.

  The spindle drive control unit 85 includes a CPU 85a, a RAM 85b, a storage unit 85c, and an interface (not shown) connected to each other via a bus. The storage unit 85c stores a control program, and the CPU 85a reads the control program into the RAM 85b, outputs a rotation command to the spindle motor 31, and controls the driving of the spindle motor 31. The spindle motor 31 rotates based on the rotation command. An encoder 31 e is connected to the spindle motor 31, and the rotational position of the spindle motor 31 is detected by the encoder 31 e, and the detected position is input to the spindle drive control unit 85. The spindle drive control unit 85 refers to the input position and performs feedback control of the spindle motor 31 until the rotational position reaches the target position. In addition, the origin position (specific position) of the spindle 34 is stored in the storage unit 85c of the spindle drive control unit 85.

  Each of the X-axis drive control unit 82, the Y-axis drive control unit 83, and the Z-axis drive control unit 84 has a CPU, a RAM, a storage unit, an interface, and the like in the same manner as the main shaft drive control unit 85. A rotation command is output to the motor 72 and the Z-axis motor 73 to control driving of the motors 71, 72, and 73. Each motor 71, 72, 73 rotates based on a rotation command. Encoders 71e, 72e, 73e are connected to the motors 71, 72, 73, and the rotational positions of the motors 71, 72, 73 are detected by the encoders 71e, 72e, 73e, and the detected positions are X-axis. The data is input to the drive control unit 82, the Y-axis drive control unit 83, and the Z-axis drive control unit 84. The X-axis drive control unit 82, the Y-axis drive control unit 83, and the Z-axis drive control unit 84 refer to the input positions and perform feedback control of the motors 71, 72, and 73 until the rotational position reaches the target position.

  The control unit 81 communicates with the A-axis drive control unit 86 and the C-axis drive control unit 87 via the communication I / F 81e. Each of the A-axis drive control unit 86 and the C-axis drive control unit 87 has a CPU, a RAM, a storage unit, an interface, and the like, similar to the X-axis drive control unit 82, and a rotation command to the A-axis motor 61 and the C-axis motor 60. A temporary stop command or the like is output, and the drive of each of the motors 61 and 60 is controlled. Each motor 61, 60 rotates based on a rotation command, and temporarily stops based on a temporary stop command. The A-axis drive control unit 86 and the C-axis drive control unit 87 transmit various notifications to the control unit 81, for example, notifications indicating that the drive of the motor has been completed and that the motor has been temporarily stopped.

  Encoders 61e and 60e are connected to the motors 61 and 60, respectively. The rotational positions of the motors 61 and 60 are detected and held by the encoders 61e and 60e, but are not fed back to the A-axis drive control unit 86 and the C-axis drive control unit 87, but are driven by the A-axis drive control unit 86 and the C-axis drive. The control unit 87 performs open loop control of the A-axis motor 61 and the C-axis motor 60. When the movements are completed, the motors 61 and 60 output a signal indicating that the movement is completed to the A-axis drive control unit 86 and the C-axis drive control unit 87. The A-axis drive control unit 86 and the C-axis drive control unit 87 control a completion response indicating that the movement of the A-axis motor 61 and the C-axis motor 60 is completed when a signal indicating that the movement is completed is input. It transmits to the part 81.

  The A-axis drive control unit 86 and the C-axis drive control unit 87 are configured to be accessible to the encoders 61e and 60e, and the A-axis drive control unit 86 or the C-axis drive control unit 87 is the A-axis motor 61 or the C-axis motor. When a command referring to the rotational position of 60 is received from the control unit 81, the A-axis drive control unit 86 or the C-axis drive control unit 87 rotates the A-axis motor 61 or the C-axis motor 60 held by the encoders 61e and 60e. The position is transmitted to the control unit 81.

  FIG. 8 is a schematic diagram for explaining an outline of rotation control of the spindle 34 by the spindle drive control unit 85. The main shaft drive control unit 85 determines a target position around the main shaft 34. As the target position, for example, when the tool is changed, the origin position (specific position) of the spindle 34 is set. The target position set by the spindle drive control unit 85 is input to the subtracter 90. The subtracter 90 receives the target position and the detected position of the spindle motor 31 output from the position conversion unit 97. The subtracter 90 calculates target position-detected position, and gives a difference value as a calculation result to the speed conversion unit 91.

  The speed converter 91 converts the given difference value between the two positions into a speed, and outputs this to the subtracter 92 as a target speed. The spindle drive control unit 85 periodically gives a command to the spindle motor 31 to control its rotation. The speed conversion unit 91 calculates and outputs the target speed in the current period based on the difference value of the given position, the period for giving the command, and the like.

  The spindle drive control unit 85 receives a signal from the encoder 31e. The encoder 31e outputs a signal corresponding to the position of the spindle motor 31 around the axis, and the spindle drive control unit 85 converts the input signal into the speed of the spindle motor 31 by the speed conversion unit 96. The target speed output from the speed converter 91 and the detected speed output from the speed converter 96 are input to the subtractor 92. The spindle drive control unit 85 converts the signal from the encoder 31e into the position of the spindle motor 31 by the position conversion unit 97. The detection position output from the position conversion unit 97 is input to the subtracter 90. The subtracter 92 calculates target speed-detected speed and outputs a difference as a calculation result. The difference calculated by the subtracter 92 is a value corresponding to the difference between the target position of the spindle motor 31 and the current position.

  The difference output from the subtracter 92 is given to the accumulating unit 93 and the adder 94. The accumulating unit 93 calculates the accumulated value by repeatedly adding the difference between the target speed and the detected speed calculated by the subtracter 92, and gives the calculated accumulated value to the adder 94. However, the spindle drive control unit 85 can control whether or not to input the accumulated value calculated by the accumulating unit 93 to the adder 94. When switching is performed so that the accumulated value is not input to the adder 94, the accumulating unit 93 resets the accumulated value.

  The adder 94 adds the difference calculated by the subtractor 92 and the accumulated value calculated by the accumulating unit 93 and gives the total value to the proportional control unit 95 as a speed command. When the switching control is performed so that the accumulated value of the accumulating unit 93 is not input to the adder 94, the adder 94 gives the difference calculated by the subtractor 92 to the proportional control unit 95 as a speed command. The proportional control unit 95 calculates a torque proportional to the speed based on the given speed command, and outputs the calculated torque to the spindle motor 31 as a torque command.

  The spindle drive control unit 85 can rotate the spindle 34 to the origin position around the axis when changing tools by performing feedback control of the spindle motor 31 as described above.

  However, when the turning tool (non-rotating tool) is mounted with a deviation from the origin position of the main spindle 34, there is a difference between the set target position and the detection position output by the position conversion unit 97. . Therefore, the subtracter 90 outputs a non-zero difference value, and this difference value is accumulated in the accumulating unit 93. The machine tool 100 according to the present embodiment performs switching control of whether or not to use the accumulated value in order to prevent the accumulated value of the accumulating unit 93 from adversely affecting the rotation control of the main spindle 34 in such a case. .

  FIG. 9 is a schematic diagram for explaining the switching control of whether or not the control using the cumulative value by the spindle drive control unit 85 is performed. When machining the workpiece W clamped on the workpiece table 16, the control device 80 causes the Z-axis drive control unit 84 to move the spindle 34 to the machining position in the Z direction (vertical direction). When the machining by the tool 4 attached to the main shaft 34 is finished, the control device 80 needs to raise the main shaft 34 from the machining position to the replacement position in order to perform tool replacement. Therefore, the control device 80 raises the spindle head 3 by the Z-axis drive control unit 84, and performs alignment to adjust the position around the axis of the spindle 34 to the origin position by the spindle drive control unit 85. The exchange position indicates a position where the grip arm 24 does not collide with the main shaft 34 even if it is conveyed.

  The control device 80 causes the spindle drive control unit 85 to perform rotation control of the spindle motor 31 using the accumulated value of the accumulation unit 93 until the spindle 34 reaches a predetermined switching position from the machining position. The switching position is a predetermined position between the machining position and the replacement position, and the position is stored in the storage unit 81c of the control unit 81 or the like. For example, the switching position is determined based on the movement speed and movement time of the main shaft 34 in the Z direction by the Z-axis drive control unit 84 and the time required for alignment of the main shaft 34 by the main shaft drive control unit 85. The position in the Z direction where the rotation alignment is completed can be calculated and set in advance at the design stage of the machine tool 100 or the like. The upper limit position of the switching position is immediately before the engagement between the pin 51 and the engagement hole 43 is released.

  When the spindle head 3 reaches the switching position, the control device 80 performs switching so that the accumulated value of the accumulating unit 93 is not used for the rotation control of the spindle motor 31 by the spindle drive control unit 85. In other words, the spindle drive control unit 85 controls the rotation of the spindle motor 31 without using the accumulated value of the accumulating unit 93 during the period from the switching position to the replacement position (or when the spindle head 3 is above the switching position). . Thereafter, when the spindle head 3 reaches the replacement position, the control device 80 performs tool replacement. Even when the tool is changed, the rotation control of the spindle 34 is switched without using the accumulated value.

  After completing the tool change, the control device 80 lowers the spindle 34 from the change position to the machining position in order to process the workpiece W by the Z-axis drive control unit 84. The controller 80 controls the rotation of the spindle motor 31 by the spindle drive controller 85 without using the accumulated value of the accumulator 93 until the spindle 34 reaches the switching position from the replacement position. When the spindle head 3 reaches the switching position, the control device 80 performs switching so that the rotation control of the spindle motor 31 by the spindle drive control unit 85 is performed using the accumulated value of the accumulation unit 93.

  Note that switching whether to use the accumulated value for rotation control by the control device 80 is performed regardless of whether the tool mounted on the spindle 24 is a rotating tool or a turning tool (non-rotating tool). In the present embodiment, the switching position when the spindle 34 is raised and lowered is the same position, but may be a different position.

  FIG. 10 is a flowchart showing the procedure of the tool change process by the control device 80. In this flowchart, processing from the time when machining on the workpiece is finished is shown. At this time, the spindle drive control unit 85 is switched so as to perform rotation control of the spindle motor 31 using the accumulated value of the accumulation unit 93.

  The control unit 81 of the control device 80 starts the tool change after finishing the machining with the tool 4 attached to the main shaft 34. The control unit 81 drives the Z-axis motor 73 by the Z-axis drive control unit 84 and starts to raise the spindle head 3 (step S1). As a result, the spindle 34 starts to move upward in the Z-axis direction from the machining position with respect to the workpiece. In addition, the control unit 81 starts the alignment process for adjusting the position of the spindle 34 around the axis to the origin position by the spindle drive control unit 85 (step S2).

  Thereafter, the control unit 81 determines whether or not the position of the main shaft 34 has reached a predetermined switching position in the Z direction (step S3). When the main shaft 34 has not reached the switching position (S3: NO), the control unit 81 continues to raise and align the main shaft 34 until reaching the switching position. When the main shaft 34 reaches the switching position (S3: YES), the control unit 81 gives a switching instruction to the main shaft drive control unit 85, thereby controlling the rotation of the main shaft motor 31 without using the accumulated value of the accumulating unit 93. Control is performed by the spindle drive control unit 85 so as to perform the control (step S4).

  Thereafter, the control unit 81 determines whether or not the position of the main shaft 34 has reached the replacement position in the Z direction (step S5). When the main shaft has not reached the replacement position (S5: NO), the control unit 81 continues to raise the main shaft 34 until it reaches the replacement position. When the spindle 34 reaches the replacement position (S5: YES), the control unit 81 stops the upward movement of the spindle head 3 by the Z-axis drive control unit 84 (step S6), and the tool attached to the spindle 34 In order to replace 4 with the next tool 4, the gripping arm 24 that grips the next tool 4 is transported to the arm swing position (step S7).

  After transporting the grip arm 24 to the arm swing position, the control unit 81 starts the spindle head 3 to be lowered by the Z-axis drive control unit 84 (step S8). Thereby, tool change is performed. Next, the control unit 81 determines whether or not the main shaft 34 has reached the switching position (step S9). When the main shaft 34 has not reached the switching position (S9: NO), the control unit 81 continues to lower the main shaft 34 until reaching the switching position. When the main shaft 34 reaches the switching position (S9: YES), the control unit 81 gives a switching instruction to the main shaft drive control unit 85, thereby performing rotation control of the main shaft motor 31 using the accumulated value of the accumulating unit 93. Thus, the spindle drive control unit 85 performs control switching (step S10), and the tool change process is terminated. Thereafter, the machine tool 100 lowers the spindle 34 to the machining position and starts machining the workpiece.

  In the machine tool 100 according to the present embodiment having the above configuration, the subtractor 92 calculates a value corresponding to the difference between the target position (specific position) of the main spindle 34 and the current position around the axis, and the accumulated value of the difference values. Is calculated by the accumulating unit 93. The target position is, for example, the origin position of the main shaft 34, and can be the position where the main shaft 34 should be when the tool is changed. The machine tool 100 switches between rotation control of the spindle motor 31 based on both the difference value by the subtractor 92 and the accumulation value by the accumulation unit 93 and rotation control of the spindle motor 31 based on the difference value without using the accumulation value. The rotation of the main shaft 34 is controlled. As a result, the machine tool 100 can switch the rotation control method of the spindle 34 so as not to perform the rotation control based on the accumulated value as necessary.

  Further, the machine tool 100 switches the rotation control method at a predetermined switching position between the machining position for the workpiece and the exchange position where the tool is exchanged. The machine tool 100 performs rotation control based on the difference value and the accumulated value from the machining position to the switching position, and performs rotation control based on the difference value from the switching position to the replacement position. The switching position is, for example, the alignment of the main shaft 34 when the alignment of the main shaft 34 around which the rotary tool is mounted and the ascent of the main shaft 34 in the Z direction from the machining position to the replacement position are performed simultaneously. It is possible to set a position that can be sufficiently completed.

  As a result, the machine tool 100 can perform high-speed and high-precision alignment by performing rotation control based on the accumulated value when aligning the spindle 34 to which the rotary tool is mounted. In addition, the machine tool 100 can switch the control method so as to perform rotation control based on the difference value without using the accumulated value after the alignment of the spindle 34, and a turning tool (non-rotating tool) is provided on the spindle 34. Even if it is mounted, it is possible to prevent an excessive load based on the accumulated value from being applied to the spindle motor 31. Further, since the control method is switched at a predetermined switching position, the machine tool 100 may switch the rotating tool and the turning tool by the same method, and any tool is mounted on the spindle 34. There is no need to determine whether or not

  In the present embodiment, the machine tool 100 switches the rotation control method of the spindle motor 31 on the condition that the position of the spindle 34 in the Z direction is a predetermined switching position. It is not limited. For example, the rotation control may be switched under the conditions of Modification 1 or Modification 2 below.

(Modification 1)
The machine tool 100 according to the first modification uses a rotation control based on a difference value without using a cumulative value from a rotation control based on the difference value and the cumulative value before at least the tool 4 is removed from the spindle 34 for tool change. The control method of the spindle motor 31 is switched. Thereby, when the tool 4 is removed from the spindle 34, the rotation control based on the accumulated value is not performed. Therefore, when the turning tool (non-rotating tool) is removed for replacement, the origin position of the spindle 34 is removed. By accumulating errors with respect to, the main shaft 34 can be prevented from rotating to a position greatly deviated from the origin position.

(Modification 2)
The machine tool 100 is configured to determine whether the tool 4 attached to the spindle 34 is a rotating tool or a turning tool (non-rotating tool), and to switch the rotation control method of the spindle motor 31 according to the determination result. Also good. The machine tool 100 stores, for example, a machining program in which machining conditions, machining contents, machining commands, and the like for a workpiece are written in the storage unit 81c of the control device 80. The control unit 81 of the control device 80 controls the X-axis drive control unit 82 to the C-axis drive control unit 87 in accordance with the machining program stored in the storage unit 81c, and performs machining on the workpiece. In this configuration, the machine tool 100 can determine whether the tool mounted on the spindle 34 is a rotating tool or a turning tool based on the contents of the machining program.

  FIG. 11 is a diagram illustrating an example of a machining program stored in the storage unit 81c. The control unit 81 of the control device 80 sequentially reads commands from the first line of the machining program, and sequentially performs processing according to the read commands. In FIG. 11, M6 is a command indicating that a tool is to be replaced, and T1 to T3 indicate tools to be mounted on the main shaft 34. For example, “M6T1” in the first line means that the first tool 4 is attached to the spindle 34. M141 is a command for setting the rotation of the main shaft 34 (hereinafter referred to as a main shaft rotation mode), and M142 is a command for setting the rotation of the work table 16 around the C axis (hereinafter referred to as a C-axis rotation mode). is there. In the spindle rotation mode, rotation with respect to the spindle 34 can be commanded, and rotation with respect to the work table 16 cannot be commanded. In the C-axis rotation mode, rotation with respect to the main shaft 34 cannot be commanded, and rotation with respect to the work table 16 can be commanded. M30 is a command indicating the end of the process.

  When the spindle rotation mode is set, it is considered that a rotating tool is mounted on the spindle 34. When the C-axis rotation mode is set, it is considered that a turning tool (non-rotating tool) is attached to the main shaft 34. Therefore, the control unit 81 of the control device 80 determines whether the tool mounted on the spindle 34 is a rotary tool or a turning tool (depending on whether the mode setting command after the tool change command M6 in the machining program is M141 or M142. It is possible to determine which is a non-rotating tool.

  FIG. 12 is a flowchart illustrating a procedure for switching processing of rotation control of the spindle 34 performed by the machine tool 100 according to the second modification. The control part 81 of the control apparatus 80 of the machine tool 100 which concerns on the modification 2 reads the instruction | command for 1 line from the machining program memorize | stored in the memory | storage part 81c (step S31). The controller 81 determines whether or not the read command is a tool change command M6 (step S32). If it is not the tool change command M6 (S32: NO), the control unit 81 performs a process according to the read command (step S33), and returns the process to step S31.

  When the read command is a tool change command (S32: YES), the control unit 81 performs tool change (step S34). Next, the control unit 81 reads the next command from the machining program (step S35), and determines whether or not the tool 4 attached to the spindle 34 is a rotating tool based on the read command (step S36). The control unit 81 can determine that the read command is a rotating tool when the command is M141, and can determine that the command is a turning tool when the command is M142. When it is determined that the tool 4 attached to the spindle 34 is a rotary tool (S36: YES), the control unit 81 performs spindle drive control so as to perform rotation control of the spindle motor 31 using the accumulated value of the accumulation unit 93. The control is switched by the unit 85 (step S37), and the process returns to step S31. When it is determined that the tool 4 mounted on the spindle 34 is not a rotary tool (S36: NO), the control unit 81 performs spindle drive control so as to perform rotation control of the spindle motor 31 based on the difference value without using the accumulated value. The control is switched by the unit 85 (step S38), and the process returns to step S31.

  As described above, the machine tool 100 according to the modified example 2 determines whether the tool 4 mounted on the spindle 34 is a rotary tool or a turning tool. When the mounted tool 4 is a rotary tool, the machine tool 100 performs rotation control of the spindle motor 31 based on the difference value of the subtracter 92 and the accumulated value of the accumulating unit 93. When the mounted tool 4 is a turning tool, the machine tool 100 does not perform rotation control based on the accumulated value, but performs rotation control based on the difference value. Thereby, when a turning tool is mounted on the spindle 34, it is possible to prevent an excessive load from being applied to the spindle motor 31 by performing rotation control based on the accumulated value.

  In the second modification described above, it is configured to determine whether the tool 4 is a rotating tool or a turning tool based on a command described in the machining program. However, the present invention is not limited to this. The machine tool 100 includes, for example, a sensor for identifying the type of the tool 4 mounted on the spindle 34, and the like, and determines whether the tool 4 is a rotating tool or a turning tool based on the output of the sensor. Good. For example, separately from the machining program, it may be registered in advance in the storage unit 80c whether each tool is a rotating tool or a turning tool, and the information may be used.

2 Tool magazine 3 Spindle head 4 Tool 5 Engaging protrusion 16 Work table 31 Spindle motor 31e Encoder 34 Spindle 40 Tool holder 41 Non-rotating flange 80 Controller 81 Controller 85 Spindle drive controller 91 Speed converter 92 Subtractor 93 Cumulative Unit 94 adder 95 proportional control unit 96 speed conversion unit

Claims (4)

A spindle that mounts a tool to process a workpiece, a storage unit that stores a tool that is mounted on the spindle, a control unit that controls replacement of the tool mounted on the spindle and the tool stored in the storage unit, A first position control means for rotating the spindle to a specific position around the axis and exchanging the tool from a machining position with respect to the workpiece in the axial direction before exchanging the tool. In a machine tool having second position control means for moving to an exchange position,
The controller is
First calculation means for calculating a value according to a difference between a position of the main shaft around the axis and the specific position;
Second calculation means for calculating a cumulative value of the values calculated by the first calculation means;
The first position control unit performs rotation control of the spindle based on the value calculated by the first calculation unit, or the value calculated by the first calculation unit and the cumulative value calculated by the second calculation unit and a switching means for performing said one of the switching control rotation of the spindle based on,
The switching means is
When the position of the main spindle moved by the second position control means is from the machining position to a predetermined position between the machining position and the exchange position, the first position control means is configured as the first calculation means. Performing rotation control of the spindle based on the calculated value and the cumulative value calculated by the second calculating means,
When the position of the main shaft moved by the second position control means is from the predetermined position to the replacement position, the first position control means is configured so that the first position of the main spindle based on the value calculated by the first calculation means To perform rotation control,
A machine tool, wherein control is switched by the first position control means . The switching means includes a rotation control of the spindle based on a value calculated by the first calculation means and a cumulative value calculated by the second calculation means before the tool is removed from the spindle for tool replacement. The machine tool according to claim 1, wherein the control of the first position control means is switched to rotation control of the spindle based on the value calculated by the first calculation means. The main shaft can be mounted with a rotating tool that performs processing by rotating the main shaft, or a non-rotating tool that performs processing without rotating,
A tool determination means for determining whether the tool mounted on the spindle is the rotating tool or the non-rotating tool;
The switching means is
When the tool determination means determines that the tool is the rotating tool, the first position control means rotates the spindle based on the value calculated by the first calculation means and the accumulated value calculated by the second calculation means. Control
When the tool determination means determines that the tool is the non-rotating tool, the first position control means performs rotation control of the spindle based on the value calculated by the first calculation means.
The machine tool according to claim 1, wherein control is switched by the first position control means. The tool mounted on the spindle and the tool stored in the storage unit are exchanged, and before the tool is exchanged, the spindle is rotated to a specific position around the axis, and the spindle is rotated with respect to the workpiece in the axial direction. In the tool change method to move from the machining position to the change position for tool change,
A first calculation step of calculating a value according to a difference between a position of the main shaft around the axis and the specific position;
A second calculation step for calculating a cumulative value of the values calculated in the first calculation step;
When the spindle is rotated to a specific position around the axis, rotation control of the spindle is performed based on the value calculated in the first calculation step, or the value calculated in the first calculation step and the first A switching step for switching whether to perform rotation control of the spindle based on the cumulative value calculated in the two calculation steps ;
In the switching step,
When the position of the spindle moved in the axial direction is from the machining position to a predetermined position between the machining position and the exchange position, the value calculated in the first calculation step and the second calculation step Rotation control around the spindle based on the cumulative value calculated by
When the position of the spindle that is moved in the axial direction is from the predetermined position to the replacement position, rotation control of the spindle based on the value calculated in the first calculation step is performed.
A tool change method characterized by switching control .

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