JP6678799B1 - Machine tool, machine tool control method, and machine tool control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of pulling out a boring tool from a work in a state where the driving of the boring tool in the direction of gravity is locked. A machine tool includes a rotary drive unit for rotationally driving a spindle, a first motor for horizontally changing a relative position of a tool with respect to a work, and a first motor for changing the relative position in a gravity direction. A second motor, a third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravity direction, and a brake mechanism for locking the drive of the second motor are provided. The control device of the machine tool controls the process of locking the drive of the second motor, the process of performing boring machining of the work while maintaining the lock of the second motor, and the first motor after the machining is completed. A process of canceling the contact between the work and the tool while the second motor is kept locked, and a process of pulling the tool out of the work while keeping the second motor locked after the process is completed are executed. [Selection diagram] Fig. 1

Description

  The present disclosure relates to a technique for controlling boring in a machine tool.

  Machine tools capable of performing boring have become widespread. The boring process is a general term for a process of forming a hole in a work and a process of polishing the formed hole. Boring is also called inner diameter processing.

  In order to facilitate understanding, one direction on the horizontal plane is hereinafter referred to as a “Z direction”, a direction of gravity is referred to as a “Y direction”, and a direction orthogonal to both the Z direction and the Y direction is referred to as an “X direction”. Called.

  When performing boring in the horizontal direction (Z direction), the machine tool first controls a servo motor for the X direction and a servo motor for the Y direction, and feeds and drives the spindle in the XY directions. Next, the machine tool controls the servo motor for the Z direction to feed and drive the spindle in the horizontal direction. Thereby, the work is cut in the horizontal direction, and a hole is formed in the work.

  If a power failure occurs during boring, the main shaft cannot maintain its holding force in the direction of gravity, and the main shaft falls in the direction of gravity. As a result, the boring tool mounted on the spindle comes into contact with the workpiece, and the boring tool is damaged.

  With respect to the technology for preventing such damage, Japanese Patent Application Laid-Open No. 61-252041 discloses a machine tool provided with a brake mechanism for a servomotor for the direction of gravity. The machine tool locks the feed drive of the spindle in the direction of gravity during boring. Thereby, the machine tool prevents the main shaft from dropping during a power failure.

JP-A-61-252041

  By the way, if the boring tool is pulled out of the workpiece while the boring tool is in contact with the workpiece, the boring tool may be damaged or the workpiece may be damaged. Therefore, the boring tool needs to be pulled out of the work after eliminating contact with the work.

  Various methods can be considered as a method of eliminating the contact between the boring tool and the work. As an example, the machine tool cancels the contact between the boring tool and the workpiece by feeding and driving the boring tool after releasing the lock of the brake mechanism. However, in this method, there is a possibility that a power failure occurs during the release of the lock, and in that case, the main shaft falls. As a result, the boring tool is damaged. Therefore, there is a demand for a technique capable of pulling out the boring tool from the workpiece in a state where the feed driving of the boring tool in the direction of gravity is locked.

  In an example of the present disclosure, a machine tool includes a main spindle to which a tool used for boring a work can be attached, a table for fixing the work, and a rotation driving unit for rotationally driving the main spindle. A position drive unit for changing a relative position of the tool with respect to the workpiece by moving at least one of the spindle and the table; The position drive section includes a first motor for changing the relative position in the horizontal direction, a second motor for changing the relative position in the gravitational direction, and changing the relative position to the horizontal direction and the gravitational direction. And a third motor for changing in a direction orthogonal to both. The machine tool further includes a brake mechanism for locking the drive of the second motor, and a control device for controlling the machine tool. The control device controls the first motor and the second motor to move the tool to a predetermined machining start position, and to move the tool to the machining start position after the brake mechanism is completed. Controlling the rotation of the second motor, and locking the drive of the second motor, and controlling the rotation drive unit and the third motor while maintaining the lock of the second motor to execute boring of the workpiece. After the boring of the workpiece is completed, the first motor is controlled to release the contact between the workpiece and the tool in a state where the lock of the second motor is maintained. Thereafter, the third motor is controlled, and a process of pulling out the tool from the workpiece while maintaining the lock of the second motor is executed.

  In an example of the present disclosure, the control device may further include, after the process of pulling out the tool from the work is completed, and before starting the next boring process of the work, the previous processing position of the work and If the next processing position of the workpiece is different in the direction of gravity, a process of unlocking the second motor is executed.

  In an example of the present disclosure, the control device may further include, after the process of pulling out the tool from the work is completed, and before starting the next boring process of the work, the previous processing position of the work and If the next processing position of the work is the same in the direction of gravity, a process for maintaining the lock of the second motor is executed.

  In an example of the present disclosure, the control device further executes a process of maintaining the lock of the second motor when the machine tool abnormally stops during boring of the workpiece.

  In an example of the present disclosure, the control device performs a process of turning the blade of the tool in a direction different from the direction of gravity after the boring of the workpiece is completed and before controlling the first motor. I do.

  In another example of the present disclosure, a method for controlling a machine tool is provided. The machine tool includes a main spindle to which a tool used for boring a work can be attached, a table for fixing the work, a rotation drive unit for rotationally driving the main spindle, the main spindle and the table. And a position drive unit for changing a relative position of the tool with respect to the workpiece by moving at least one of the positions. The position drive section includes a first motor for changing the relative position in the horizontal direction, a second motor for changing the relative position in the gravitational direction, and changing the relative position to the horizontal direction and the gravitational direction. And a third motor for changing in a direction orthogonal to both. The machine tool further includes a brake mechanism for locking the drive of the second motor. The control method includes controlling the first motor and the second motor to move the tool to a predetermined machining start position, and controlling the brake mechanism after the moving step is completed. Locking the drive of the motor, controlling the rotation drive unit and the third motor while maintaining the lock of the second motor, and performing boring of the workpiece; and boring the workpiece. Controlling the first motor after the completion, and releasing the contact between the workpiece and the tool while maintaining the lock of the second motor; and controlling the third motor after the completion of the releasing step. And pulling out the tool from the workpiece while maintaining the lock of the second motor.

  In another example of the present disclosure, a control program for a machine tool is provided. The machine tool includes a main spindle to which a tool used for boring a work can be attached, a table for fixing the work, a rotation drive unit for rotationally driving the main spindle, the main spindle and the table. And a position drive unit for changing a relative position of the tool with respect to the workpiece by moving at least one of the positions. The position drive section includes a first motor for changing the relative position in the horizontal direction, a second motor for changing the relative position in the gravitational direction, and changing the relative position to the horizontal direction and the gravitational direction. And a third motor for changing in a direction orthogonal to both. The machine tool further includes a brake mechanism for locking the drive of the second motor. The control program controls the machine tool to control the first motor and the second motor to move the tool to a predetermined machining start position, and to control the brake mechanism after the moving step is completed. Locking the drive of the second motor, controlling the rotation drive unit and the third motor while maintaining the lock of the second motor, and performing boring of the workpiece; After the boring of the workpiece is completed, the first motor is controlled, and the contact between the workpiece and the tool is released while the lock of the second motor is maintained. Controlling the third motor to pull out the tool from the workpiece while maintaining the lock of the second motor. .

  The above and other objects, features, aspects and advantages of the present invention will become apparent from the following detailed description of the invention that is understood in connection with the accompanying drawings.

It is a figure showing an example of the device composition of a machine tool. It is a figure which shows the process of a boring process in a time series. FIG. 3 is a diagram showing a boring process subsequent to FIG. 2 in chronological order. It is a figure which shows the flow of boring when the boring position at the time of N-th boring and the boring position at the time of N + 1-th boring are the same in the direction of gravity. It is a figure which shows the flow of boring when the boring position at the time of N-th boring and the boring position at the time of N + 1-th boring differ in the direction of gravity. FIG. 2 is a schematic diagram illustrating an example of a hardware configuration of a CPU (Central Processing Unit) unit. FIG. 2 is a schematic diagram illustrating an example of a hardware configuration of a CNC (Computer Numerical Control) unit. It is a figure showing an example of the functional composition of a machine tool. It is a flowchart which shows the flow of boring.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed description thereof will not be repeated. In addition, each embodiment and each modification described below may be appropriately and selectively combined.

<A. Configuration of machine tool 10>
First, an apparatus configuration of the machine tool 10 will be described with reference to FIG. FIG. 1 is a diagram illustrating an example of a device configuration of the machine tool 10.

  FIG. 1 shows a machine tool 10 as a machining center. Hereinafter, the machine tool 10 as a machining center will be described, but the machine tool 10 is not limited to the machining center. For example, the machine tool 10 may be a lathe or another cutting machine or grinding machine. Typically, the machine tool 10 is a horizontal machining center on which tools are mounted in a horizontal direction.

  As shown in FIG. 1, the machine tool 10 includes a control device 50, a brake mechanism 110, servo drivers 111R, 111X to 111Z, servo motors 112R, 112X to 112Z, a moving body 113, a spindle head 131, , A boring tool 134 and a table 136.

  The “control device 50” in this specification means a device that controls the machine tool 10. The device configuration of the control device 50 is arbitrary. The control device 50 may be configured by a single control unit, or may be configured by a plurality of control units. In the example of FIG. 1, the control device 50 includes a CPU unit 20 as a PLC (Programmable Logic Controller), a CNC unit 30, and an I / O (Input Output) unit 40. The CPU unit 20, the CNC unit 30, and the I / O unit 40 are connected to the field bus B and communicate with each other via the field bus B.

  In the following description, the direction in which the boring tool 134 makes a hole (that is, the left-right direction on the paper) is referred to as “Z direction”, and the direction of gravity (that is, the vertical direction on the paper) is referred to as “Y direction”. The direction orthogonal to both the direction and the Y direction is referred to as “X direction”.

  The spindle head 131 includes a spindle 132 and a housing 133. The main shaft 132 is arranged inside the housing 133. A tool for processing a workpiece W, which is a workpiece, is mounted on the main shaft 132. In the example of FIG. 1, a boring tool 134 used for boring a workpiece W is mounted on a main shaft 132. The boring tool 134 has one blade protruding from the tool axis.

  The CPU unit 20 controls various units constituting the control device 50 according to a PLC program prepared in advance. The PLC program is described in, for example, a ladder program.

  The CNC unit 30 starts execution of a machining program prepared in advance based on receiving a machining start command from the CPU unit 20, and controls the servo drivers 111R, 111X to 111Z according to the machining program. The work W fixed to the table 136 is processed. The machining program is described in, for example, an NC (Numerical Control) program.

  The servo driver 111R sequentially receives the input of the target rotation speed from the CNC unit 30, and controls the servo motor 112R (rotation drive unit). The servo motor 112R drives the main shaft 132 to rotate about the axis in the Z direction. More specifically, the servo driver 111R calculates the actual rotation speed of the servo motor 112R from a feedback signal of an encoder (not shown) for detecting the rotation angle of the servo motor 112R, and calculates the actual rotation speed as the target rotation speed. If the actual rotation speed is higher than the target rotation speed, the rotation speed of the servo motor 112R is decreased. As described above, the servo driver 111R approaches the rotation speed of the servo motor 112R to the target rotation speed while sequentially receiving the feedback of the rotation speed of the servo motor 112R.

  The servo driver 111X sequentially receives the input of the target position from the CNC unit 30, and controls the servo motor 112X (first motor). The servo motor 112X feeds and drives the moving body 113 to which the spindle head 131 is attached via a ball screw (not shown), and feeds and drives the spindle 132 to an arbitrary position in the X direction. More specifically, the servo driver 111X calculates the actual position of the moving body 113 from a feedback signal of an encoder (not shown) for detecting the rotation angle of the servo motor 112X, and the actual position is smaller than the target position. In this case, the actual position of the servo motor 112X is raised, and when the actual position is larger than the target position, the actual position of the servo motor 112X is lowered. As described above, the servo driver 111X moves the actual position of the servo motor 112X closer to the target position while sequentially receiving feedback of the actual position of the servo motor 112X. Accordingly, the servo driver 111X feeds and drives the main shaft 132 to an arbitrary position in the X direction.

  The servo driver 111Y sequentially receives the input of the target position from the CNC unit 30, and controls the servo motor 112Y (second motor). The servo motor 112Y feeds and drives the moving body 113 to which the spindle head 131 is attached via a ball screw (not shown), and feeds and drives the spindle 132 to an arbitrary position in the Y direction. The method of controlling servo motor 112Y by servo driver 111Y is the same as that of servo driver 111X, and therefore, description thereof will not be repeated.

  The servo driver 111Z sequentially receives the input of the target position from the CNC unit 30, and controls the servo motor 112Z (third motor). The servo motor 112Z feeds and drives the movable body 113 to which the spindle head 131 is attached via a ball screw (not shown), and feeds and drives the spindle 132 to an arbitrary position in the Z direction. The method of controlling servo motor 112Z by servo driver 111Z is the same as that of servo driver 111X, and therefore, description thereof will not be repeated.

  The CPU unit 20 outputs a control command to the brake mechanism 110 via the I / O unit 40, and locks the feed drive of the gravity direction servo motor 112Y or unlocks the servo motor 112Y. The brake mechanism 110 is, for example, an electromagnetic brake, an electromagnetic clutch, or another hardware mechanism that can lock the feed drive of the servomotor 112Y. When the brake mechanism 110 locks the feed drive of the servo motor 112Y, the moving body 113 does not fall even if a power failure occurs. This prevents the boring tool 134 from being damaged.

  In the above description, the configuration in which the machine tool 10 changes the relative position of the workpiece W with respect to the boring tool 134 by driving and driving the main shaft 132 has been described, but the machine tool 10 is a fixing device for the workpiece W. The relative position may be changed by driving and driving the table 136, or the relative position may be changed by driving and driving both the main shaft 132 and the table 136. That is, the servo motor 112X may be configured to feed and drive the main shaft 132 in the X direction, or may be configured to feed and drive the table 136 in the X direction. The servo motor 112Y may be configured to feed and drive the main shaft 132 in the Y direction, or may be configured to feed and drive the table 136 in the Y direction. The servo motor 112Z may be configured to feed and drive the main shaft 132 in the Z direction, or may be configured to feed and drive the table 136 in the Z direction.

<B. Boring>
The boring process will be described with reference to FIGS. 2 and 3 are diagrams showing the boring process in time series.

  In step S1, the control device 50 of the machine tool 10 releases the lock of the servomotor 112Y by the brake mechanism 110, and sets the main shaft 132 in a state in which the main shaft 132 can be fed and driven in the gravity direction (Y direction). Thereafter, the control device 50 controls the servomotors 112X and 112Y to feed and drive the boring tool 134 in the XY directions. Accordingly, the boring tool 134 moves to a predetermined machining start position.

  In step S2, it is assumed that the control device 50 has completed the process of moving the boring tool 134 to a predetermined machining start position. Based on this, the control device 50 controls the brake mechanism 110 to lock the feed drive of the servomotor 112Y. As a result, the boring tool 134 does not move in the direction of gravity (Y direction).

  In step S3, the control device 50 controls the servomotor 112R and the servomotor 112Z to execute boring of the workpiece W while maintaining the lock of the servomotor 112Y. Thereby, the boring tool 134 digs the work W in the Z direction while rotating.

  In step S4, it is assumed that the boring process on the workpiece W has been completed. Here, “completion of boring” means that the formation of one inner diameter (hole) is completed. Since the blade of the boring tool 134 protrudes from the tool axis, only the blade portion is in contact with the workpiece W when the boring process is completed. In order to eliminate this contact, it is necessary to drive the boring tool 134, but since the feed drive in the Y direction (gravity direction) is locked, the control device 50 controls only the feed drive in the X direction. Then, the contact between the boring tool 134 and the workpiece W is eliminated. That is, the control device 50 controls the servomotor 112X after the boring of the work W is completed, and eliminates the contact between the work W and the boring tool 134 while maintaining the lock of the servomotor 112Y. At this time, the control device 50 drives the servomotor 112X to drive the blade of the boring tool 134 in a direction away from the inner surface of the workpiece W.

  Note that, depending on the specification, the blade of the boring tool 134 may be oriented in the Y direction (gravity direction) when the boring process is completed. In this case, the contact between the boring tool 134 and the workpiece W is not eliminated only by the feed driving of the boring tool 134 in the X direction. Therefore, when the blade of the boring tool 134 is oriented in the Y direction (the direction of gravity), the control device 50 directs the blade of the boring tool 134 in a direction different from the Y direction (the direction of gravity). The boring tool 134 is fed and driven in the X direction to eliminate contact between the boring tool 134 and the workpiece W. Typically, the control device 50 directs the blade of the boring tool 134 to the positive side in the X direction, and then moves the boring tool 134 to the negative side in the X direction. Alternatively, the control device 50 directs the blade of the boring tool 134 to the negative side in the X direction, and then moves the boring tool 134 to the positive side in the X direction. Thereby, the contact between the boring tool 134 and the workpiece W is more reliably eliminated.

  In step S5, the control device 50 controls the servomotor 112Z, and pulls out the boring tool 134 from the workpiece W while maintaining the lock of the servomotor 112Y.

  As described above, when the boring operation is completed, the control device 50 feeds and drives the boring tool 134 in the X direction, and releases the contact between the workpiece W and the boring tool 134. Thus, when the boring tool 134 is pulled out of the work W, it is not necessary to release the lock of the servomotor 112Y. As a result, the machine tool 10 can shorten the machining time and can surely prevent the boring tool 134 from dropping due to a power failure or an error.

  Further, after the contact between the boring tool 134 and the workpiece W is eliminated, the boring tool 134 is pulled out of the workpiece W, so that the boring tool 134 does not damage the workpiece W and also prevents the boring tool 134 from being damaged. Can come off.

<C. Continuous boring>
Hereinafter, with reference to FIG. 4 and FIG. 5, the control of the brake mechanism 110 when shifting from the N-th boring to the (N + 1) -th boring will be described. "N" represents an integer of 1 or more.

  FIG. 4 is a diagram showing the flow of boring when the boring position at the time of the N-th boring and the boring position at the time of the (N + 1) -th boring are the same in the direction of gravity.

  In step S11, it is assumed that the process of pulling out the boring tool 134 from the workpiece W ends, and the N-th boring operation ends. In the example of FIG. 4, a hole is formed at the processing position P of the workpiece W by the N-th boring.

  It is assumed that the boring processing is specified to be performed continuously in the processing program. In this case, the control device 50 acquires the next machining position PX (coordinate value) from the machining program, and determines the machining position P at the time of the Nth boring operation and the machining position PX at the time of the N + 1th boring operation in the direction of gravity. (Y direction). In this example, it is assumed that the processing position P and the processing position PX are the same in the direction of gravity. In this case, in step S12, the control device 50 performs the positioning of the boring tool 134 only in the X direction while maintaining the locked state of the servomotor 112Y.

  Thereafter, in step S13, the control device 50 starts the (N + 1) th boring process, and forms a hole at the processing position PX of the work W.

  As described above, after the process of pulling out the boring tool 134 from the work W is completed and before the next boring processing of the work W is started, the control device 50 determines the last processing position of the work W When the next processing position after W is the same in the direction of gravity, the locked state of the servomotor 112Y by the brake mechanism 110 is maintained. Accordingly, the control device 50 does not have to release the lock of the brake mechanism 110 when the process proceeds from the N-th boring process to the (N + 1) -th boring process, thereby shortening the processing time.

  FIG. 5 is a diagram showing the flow of boring when the boring position at the time of the N-th boring and the boring position at the time of the (N + 1) -th boring are different in the direction of gravity.

  In step S21, it is assumed that the process of pulling out the boring tool 134 from the workpiece W ends, and the N-th boring operation ends. In the example of FIG. 5, a hole is formed at the processing position P of the workpiece W by the Nth boring.

  It is assumed that the boring processing is specified to be performed continuously in the processing program. In this case, the control device 50 acquires the next machining position PY (coordinate value) from the machining program, and determines the machining position P at the time of the Nth boring operation and the machining position PY at the time of the N + 1th boring operation in the direction of gravity. Will be compared. In this example, it is assumed that the processing position P and the processing position PY are different in the direction of gravity. In this case, the control device 50 releases the lock of the servomotor 112Y.

  Thereafter, in step S22, the control device 50 performs the positioning of the boring tool 134 in the X direction and the Y direction. The control device 50 locks the feed drive of the servo motor 112Y again based on the completion of the positioning.

  Thereafter, in step S23, the control device 50 starts the (N + 1) th boring process, and forms a hole at the processing position PY of the work W.

  As described above, after the process of pulling out the boring tool 134 from the work W is completed and before the next boring processing of the work W is started, the control device 50 determines the last processing position of the work W If the next processing position after W is different in the direction of gravity, the locked state of the servomotor 112Y by the brake mechanism 110 is released. Thereby, the control device 50 can arbitrarily change the boring position in the direction of gravity when shifting from the N-th boring operation to the (N + 1) -th boring operation.

<D. Hardware Configuration of CPU Unit 20>
Next, a hardware configuration of the CPU unit 20 will be described with reference to FIG. FIG. 6 is a schematic diagram illustrating an example of a hardware configuration of the CPU unit 20.

  The CPU unit 20 includes a processor 51, a read only memory (ROM) 52, a random access memory (RAM) 53, a communication interface 54, a field bus controller 55, and a storage device 70. These components are connected to the internal bus 59.

  The processor 51 is constituted by, for example, at least one integrated circuit. The integrated circuit includes, for example, at least one CPU (Central Processing Unit), at least one GPU (Graphics Processing Unit), at least one ASIC (Application Specific Integrated Circuit), at least one FPGA (Field Programmable Gate Array), or And the like.

  The processor 51 controls the operation of the CPU unit 20 by executing various programs such as the PLC program 72. The PLC program 72 defines commands for controlling various devices in the machine tool 10. The processor 51 reads the PLC program 72 from the storage device 70 or the ROM 52 to the RAM 53 based on the reception of the execution instruction of the PLC program 72. The RAM 53 functions as a working memory and temporarily stores various data necessary for executing the PLC program 72.

  The communication interface 54 is connected to a LAN (Local Area Network), an antenna, and the like. The CPU unit 20 exchanges data with an external device (for example, a server) via the communication interface 54. The CPU unit 20 may be configured to be able to download the PLC program 72 from the external device.

  The fieldbus controller 55 is an interface for realizing communication with various units connected to the fieldbus. Examples of units connected to the field bus include a CNC unit 30, an I / O unit 40, and the like.

  The storage device 70 is, for example, a storage medium such as a hard disk or a flash memory. The storage device 70 stores a PLC program 72 and the like. The storage location of the PLC program 72 is not limited to the storage device 70, and may be stored in a storage area (for example, a cache memory) of the processor 51, a ROM 52, a RAM 53, an external device (for example, a server), or the like.

<E. Hardware configuration of CNC unit 30>
Next, a hardware configuration of the CNC unit 30 will be described with reference to FIG. FIG. 7 is a schematic diagram illustrating an example of a hardware configuration of the CNC unit 30.

  The CNC unit 30 includes a processor 101, a ROM 102, a RAM 103, a communication interface 104, a fieldbus controller 105, and a storage device 120. These components are connected to the internal bus 109.

  The processor 101 is configured by, for example, at least one integrated circuit. The integrated circuit may be configured by, for example, at least one CPU, at least one GPU, at least one ASIC, at least one FPGA, or a combination thereof.

  The processor 101 controls the operation of the CNC unit 30 by executing various programs such as a machining program 122 (control program). The processing program 122 defines various instructions for realizing the processing of the work. The processor 101 reads the processing program 122 from the storage device 120 or the ROM 102 to the RAM 103 based on the reception of the execution instruction of the processing program 122. The RAM 103 functions as a working memory, and temporarily stores various data necessary for executing the machining program 122.

  The communication interface 104 is connected to a LAN, an antenna, or the like. The CNC unit 30 exchanges data with an external device (for example, a server) via the communication interface 104. The CNC unit 30 may be configured to be able to download the processing program 122 from the external device.

  The fieldbus controller 105 is an interface for realizing communication with various units connected to the fieldbus. Examples of units connected to the field bus include a CPU unit 20, an I / O unit 40, and the like.

  The storage device 120 is, for example, a storage medium such as a hard disk or a flash memory. The storage device 120 stores a processing program 122 and the like. The storage location of the machining program 122 is not limited to the storage device 120, and may be stored in a storage area (for example, a cache memory) of the processor 101, the ROM 102, the RAM 103, an external device (for example, a server), or the like.

  The machining program 122 may be provided as a part of an arbitrary program, not as a single program. In this case, the processing by the processing program 122 is realized in cooperation with an arbitrary program. Even a program that does not include such some modules does not depart from the spirit of the machining program 122 according to the present embodiment. Furthermore, some or all of the functions provided by the machining program 122 may be realized by dedicated hardware. Furthermore, the machine tool 10 may be configured in a form such as a so-called cloud service in which at least one server executes a part of the processing of the machining program 122.

<F. Functional Configuration of Machine Tool 10>
The functional configuration of the machine tool 10 will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of a functional configuration of the machine tool 10.

  The machine tool 10 includes a control device 50, a rotation drive unit 160, a position drive unit 162, and a brake mechanism 110 as main hardware components. Control device 50 includes, for example, CPU unit 20 and CNC unit 30.

  The rotation drive unit 160 is a mechanism that controls rotation of the main shaft 132 (see FIG. 1). As an example, the rotation drive unit 160 includes the above-described servo driver 111R (see FIG. 1) and the above-described servo motor 112R (see FIG. 1).

  The position drive unit 162 is a mechanism that changes the position of the boring tool 134 relative to the workpiece by moving at least one of the main shaft 132 and the table 136 (see FIG. 1). As an example, the position driving unit 162 includes the above-described servo drivers 111X to 111Z (see FIG. 1) and the above-described servo motors 112X to 112Z (see FIG. 1).

  The CNC unit 30 includes a processing control unit 152 and a brake control unit 154 as a functional configuration.

  The processing control unit 152 controls the servo drivers 111R, 111X to 111Z according to a predetermined processing program 122 to process the work.

  The brake control unit 154 outputs a lock command for enabling the brake mechanism 110, a lock release command for disabling the brake mechanism 110, and the like to the CPU unit 20 according to a command being executed in the machining program 122. I do. The lock command and the lock release command are input to the PLC program 72 in the CPU unit 20, for example.

  Further, when the machine tool 10 abnormally stops during boring of a workpiece, the brake control unit 154 enables the lock of the brake mechanism 110 and maintains the lock of the servomotor 112 </ b> Y that performs the feed driving in the gravity direction. The abnormality to be detected is, for example, occurrence of an earthquake or power failure. The earthquake is detected, for example, based on the fact that the output value of an acceleration sensor mounted on the machine tool 10 has exceeded a predetermined value. The power failure is detected by, for example, a power failure detection circuit mounted on the machine tool 10. When an abnormality occurs, the boring tool 134 can be more reliably prevented from falling by maintaining the lock of the servomotor 112Y.

  When receiving the lock release command from the CNC unit 30, the PLC program 72 invalidates the lock of the servomotor 112Y by the brake mechanism 110. More specifically, the CPU unit 20 starts supplying electric power to the brake mechanism 110, and generates an electromagnetic force in the coil of the brake mechanism 110. By the electromagnetic force, the brake is separated from the servomotor 112Y, and the servomotor 112Y becomes rotatable.

  On the other hand, when the PLC program 72 receives a lock command from the CNC unit 30, the PLC program 72 enables locking of the servomotor 112Y by the brake mechanism 110. More specifically, CPU unit 20 stops the supply of electric power to brake mechanism 110 and eliminates the electromagnetic force generated in the coil of brake mechanism 110. When the electromagnetic force disappears, the brake contacts the servomotor 112Y, and the servomotor 112Y cannot rotate.

<G. Flow chart for boring>
With reference to FIG. 9, a flow of boring processing will be described. FIG. 9 is a flowchart showing the flow of boring.

  The process shown in FIG. 9 is realized by the control device 50 of the machine tool 10 (typically, the processor 101 of the CNC unit 30) executing the above-described machining program 122 (see FIG. 8). In other aspects, some or all of the processing may be performed by circuit elements or other hardware.

  When the boring processing command specified in the processing program 122 is executed, the control device 50 sequentially executes the processing of each step shown in FIG.

  More specifically, in step S110, control device 50 determines whether the current position of boring tool 134 and the processing position of work W (ie, boring position) during the next boring operation are the same in the direction of gravity. Determine whether or not. When controller 50 determines that the current position of boring tool 134 and the boring position at the time of the next boring operation are the same in the direction of gravity (YES in step S110), control is switched to step S112. Otherwise (NO in step S110), control device 50 switches the control to step S114.

  In step S112, the control device 50 feeds and drives the boring tool 134 toward the machining start position defined in the current execution line of the machining program 122. At this time, since the control device 50 does not need to feed and drive the boring tool 134 in the direction of gravity (Y direction), the control device 50 feeds and drives the boring tool 134 only in the X direction.

  In step S114, the control device 50 releases the lock of the servomotor 112Y by the brake mechanism 110, and sets the main shaft 132 in a state in which the main shaft 132 can be fed and driven in the gravity direction.

  In step S116, the control device 50 feeds and drives the boring tool 134 toward the machining start position defined in the current execution line of the machining program 122. At this time, the control device 50 feeds and drives the boring tool 134 in the X direction and the Y direction.

  In step S118, the control device 50 controls the brake mechanism 110 to lock the feed driving of the servo motor 112Y. As a result, the boring tool 134 does not move in the direction of gravity (Y direction).

  In step S120, the control device 50 controls the servomotor 112R and the servomotor 112Z, and feeds and drives the boring tool 134 in the Z direction while rotating and driving. Thus, boring of the workpiece is started.

  It is assumed that the boring of the workpiece has been completed in step S122. Based on this, the control device 50 controls the servomotor 112X to feed and drive the boring tool 134 in the X direction, thereby eliminating the contact between the workpiece W and the boring tool 134.

  In step S124, the control device 50 controls the servomotor 112Z to pull out the boring tool 134 from the work.

<H. Summary>
As described above, when the boring process is completed, the machine tool 10 feeds and drives the boring tool 134 in the X direction, and releases the contact between the workpiece W and the boring tool 134. Thus, when the boring tool 134 is pulled out of the work W, it is not necessary to release the lock of the servomotor 112Y. As a result, the machine tool 10 can shorten the machining time and can surely prevent the boring tool 134 from dropping due to a power failure or an error.

  Further, after the contact between the boring tool 134 and the workpiece W is eliminated, the boring tool 134 is pulled out of the workpiece W, so that the boring tool 134 does not damage the workpiece W and also prevents the boring tool 134 from being damaged. Can come off.

  The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  10 machine tool, 20 CPU unit, 30 CNC unit, 40 I / O unit, 50 control device, 51, 101 processor, 52, 102 ROM, 53, 103 RAM, 54, 104 communication interface, 55, 105 field bus controller, 59, 109 Internal bus, 70, 120 storage device, 72 PLC program, 110 brake mechanism, 111R, 111X, 111Y, 111Z servo driver, 112R, 112X, 112Y, 112Z servomotor, 113 moving body, 122 machining program, 131 spindle Head, 132 spindle, 133 housing, 134 boring tool, 136 table, 152 machining control unit, 154 brake control unit, 160 rotation drive unit, 162 position drive unit.

Claims (7)

A machine tool,
A spindle on which a tool used for boring a workpiece can be attached;
A table for fixing the work,
A rotation drive unit for rotationally driving the spindle,
By moving at least one of the position of the spindle and the table, a position drive unit for changing the relative position of the tool with respect to the work,
The position drive unit includes:
A first motor for changing the relative position in the horizontal direction;
A second motor for changing the relative position in the direction of gravity,
A third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravitational direction,
A brake mechanism for locking the drive of the second motor;
Further comprising a control device for controlling the machine tool,
The control device includes:
Controlling the first motor and the second motor to move the tool to a predetermined machining start position;
Controlling the brake mechanism after the process of moving the tool to the machining start position is completed, and locking the driving of the second motor;
A process of controlling the rotation drive unit and the third motor in a state where the lock of the second motor is maintained, and performing boring of the workpiece;
A process of controlling the first motor after the boring of the work is completed, and canceling the contact between the work and the tool while maintaining the lock of the second motor;
A machine tool that controls the third motor after the completion of the canceling process, and performs a process of pulling out the tool from the workpiece while the lock of the second motor is maintained.   The control device may further include, after the process of pulling out the tool from the work and before starting the next boring process of the work, a previous machining position of the work, and a next position of the work. The machine tool according to claim 1, wherein when the processing position is different in the direction of gravity, a process of unlocking the second motor is executed.   The control device may further include, after finishing the process of pulling out the tool from the work and before starting the next boring work on the work, a previous machining position of the work and a next work position of the work. 3. The machine tool according to claim 1, wherein when the processing position is the same in the direction of gravity, a process of maintaining the lock of the second motor is executed. 4.   4. The control device according to claim 1, wherein the control device further executes a process of maintaining the lock of the second motor when the machine tool stops abnormally during boring of the workpiece. 5. The described machine tool.   The control device performs a process of turning the blade of the tool in a direction different from the direction of gravity after the boring of the workpiece is completed and before controlling the first motor. 5. The machine tool according to any one of 4. A method for controlling a machine tool,
The machine tool is
A spindle on which a tool used for boring a workpiece can be attached;
A table for fixing the work,
A rotation drive unit for rotationally driving the spindle,
By moving at least one of the position of the spindle and the table, a position drive unit for changing the relative position of the tool with respect to the work,
The position drive unit includes:
A first motor for changing the relative position in the horizontal direction;
A second motor for changing the relative position in the direction of gravity,
A third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravitational direction,
A brake mechanism for locking the drive of the second motor;
The control method includes:
Controlling the first motor and the second motor, and moving the tool to a predetermined machining start position;
Controlling the brake mechanism after the moving step is completed, and locking the driving of the second motor;
Controlling the rotation drive unit and the third motor in a state where the lock of the second motor is maintained, and performing boring of the work;
Controlling the first motor after the boring of the work is completed, and eliminating the contact between the work and the tool while maintaining the lock of the second motor;
Controlling the third motor after the completion of the canceling step, and withdrawing the tool from the workpiece while maintaining the lock of the second motor. A control program for a machine tool,
The machine tool is
A spindle on which a tool used for boring a workpiece can be attached;
A table for fixing the work,
A rotation drive unit for rotationally driving the spindle,
By moving at least one of the position of the spindle and the table, a position drive unit for changing the relative position of the tool with respect to the work,
The position drive unit includes:
A first motor for changing the relative position in the horizontal direction;
A second motor for changing the relative position in the direction of gravity,
A third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravitational direction,
A brake mechanism for locking the drive of the second motor;
The control program, the machine tool,
Controlling the first motor and the second motor, and moving the tool to a predetermined machining start position;
Controlling the brake mechanism after the moving step is completed, and locking the driving of the second motor;
Controlling the rotation drive unit and the third motor in a state where the lock of the second motor is maintained, and performing boring of the work;
Controlling the first motor after the boring of the work is completed, and eliminating the contact between the work and the tool while maintaining the lock of the second motor;
Controlling the third motor after the completion of the canceling step, and withdrawing the tool from the workpiece while the lock of the second motor is maintained.

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