JP2020204933A - Machine tool, control method for machine tool, and control program for machine tool - Google Patents

Abstract

To provide a technique that makes it possible to pull a boring tool from a work piece while locking the drive of the boring tool in a gravity direction.SOLUTION: A machine tool comprises: a rotating drive unit that rotatably drives a main shaft; a first motor for changing a relative position of a tool with respect to a work piece in a horizontal direction; a second motor for changing the relative position in a gravity direction; 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 drive of the second motor. A control device for the machine tool performs processes of: locking drive of the second motor; performing a boring process in a work piece while keeping the second motor locked; controlling the first motor after the boring process and cancelling contact between the work piece and the tool while keeping the second motor locked; and pulling the tool from the work piece while keeping the second motor locked after the control and cancellation process.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to techniques for controlling boring in machine tools.

Machine tools capable of boring are widespread. Boring is a general term for processing to form holes in a work and polishing the formed holes. Boring is also called inner diameter machining.

For ease of understanding, in the following, one direction on the horizontal plane is referred to as "Z direction", the direction of gravity is referred to as "Y direction", and the direction orthogonal to both Z direction and Y direction is referred to as "X direction". It is called.

When boring is performed in the horizontal direction (Z direction), the machine tool first controls a servomotor for the X direction and a servomotor for the Y direction, and feeds and drives the spindle in the XY direction. Next, the machine tool controls the servomotor for the Z direction and feeds and drives the spindle in the horizontal direction. As a result, the work is cut in the horizontal direction, and holes are formed in the work.

If a power failure occurs during the boring process, the holding force of the spindle in the direction of gravity cannot be maintained, and the spindle falls in the direction of gravity. As a result, the boring tool mounted on the spindle comes into contact with the work, and the boring tool is damaged.

Regarding a technique for preventing such damage, Patent Document 1 (Japanese Unexamined Patent Publication 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. As a result, the machine tool prevents the spindle from falling during a power failure.

Japanese Unexamined Patent Publication No. 61-252041

By the way, if the boring tool is pulled out from the work while the boring tool and the work are in contact with each other, the boring tool may be damaged or the work may be damaged. Therefore, the boring tool needs to be pulled out from the work after eliminating the contact with the work.

Various methods can be considered as a method for eliminating the contact between the boring tool and the work. As an example, the machine tool releases the lock of the brake mechanism and then feeds and drives the boring tool to eliminate the contact between the boring tool and the work. However, with this method, a power failure may occur during unlocking, in which case the spindle will fall. 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 work in a state where the feed drive of the boring tool in the direction of gravity is locked.

In one example of the present disclosure, a machine tool includes a spindle to which a tool used for boring of a workpiece can be attached, a table for fixing the workpiece, and a rotary drive unit for rotationally driving the spindle. A position driving unit for changing the relative position of the tool with respect to the work is provided by moving at least one position of the spindle and the table. The position driving unit includes a first motor for changing the relative position in the horizontal direction, a second motor for changing the relative position in the gravity direction, and the relative position in the horizontal direction and the gravity direction. It includes a third motor for changing in a direction orthogonal to both of the above. 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, and after the process of moving the tool to a predetermined machining start position and the process of moving the tool to the machining start position are completed, the brake mechanism A process of controlling the drive of the second motor to lock the drive of the second motor, and a process of controlling the rotary drive unit and the third motor while maintaining the lock of the second motor to execute the boring process of the work. After the boring process of the work is completed, the process of controlling the first motor and canceling the contact between the work and the tool while maintaining the lock of the second motor and the process of canceling the contact are completed. Later, the third motor is controlled, and the process of pulling out the tool from the work is executed while the lock of the second motor is maintained.

In one example of the present disclosure, the control device is further set to the previous machining position of the work after the process of pulling out the tool from the work is completed and before the next boring of the work is started. If the next machining position of the work is different in the direction of gravity, the process of unlocking the second motor is executed.

In one example of the present disclosure, the control device is further set to the previous machining position of the work after the process of pulling out the tool from the work is completed and before the next boring of the work is started. If the next machining position of the work is the same in the direction of gravity, the process of maintaining the lock of the second motor is executed.

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

In one example of the present disclosure, the control device executes a process of directing the blade of the tool in a direction different from the direction of gravity after the boring process of the work is completed and before controlling the first motor. To do.

Another example of the present disclosure provides a method of controlling a machine tool. The machine tool includes a spindle to which a tool used for boring of a workpiece can be attached, a table for fixing the workpiece, a rotary drive unit for rotationally driving the spindle, and the spindle and the table. A position driving unit for changing the relative position of the tool with respect to the work is provided by moving at least one position of the above. The position driving unit includes a first motor for changing the relative position in the horizontal direction, a second motor for changing the relative position in the gravity direction, and the relative position in the horizontal direction and the gravity direction. It includes a third motor for changing in a direction orthogonal to both of the above. The machine tool further includes a braking mechanism for locking the drive of the second motor. The control method controls the first motor and the second motor, controls the step of moving the tool to a predetermined machining start position, and controls the brake mechanism after the moving step is completed, and controls the second motor. The step of locking the drive of the motor, the step of controlling the rotary drive unit and the third motor while maintaining the lock of the second motor, and executing the boring of the work, and the boring of the work After the completion, the first motor is controlled, and the third motor is controlled after the step of canceling the contact between the work and the tool while maintaining the lock of the second motor and the step of canceling the contact are completed. Then, the step of pulling out the tool from the work while maintaining the lock of the second motor is provided.

In another example of the present disclosure, a machine tool control program is provided. The machine tool includes a spindle to which a tool used for boring of a workpiece can be attached, a table for fixing the workpiece, a rotary drive unit for rotationally driving the spindle, and the spindle and the table. A position driving unit for changing the relative position of the tool with respect to the work is provided by moving at least one position of the above. The position driving unit includes a first motor for changing the relative position in the horizontal direction, a second motor for changing the relative position in the gravity direction, and the relative position in the horizontal direction and the gravity direction. It includes a third motor for changing in a direction orthogonal to both of the above. The machine tool further includes a braking mechanism for locking the drive of the second motor. The control program controls the first motor and the second motor to the machine tool, and controls the brake mechanism after the step of moving the tool to a predetermined machining start position and the step of moving the tool are completed. Then, a step of locking the drive of the second motor, a step of controlling the rotary drive unit and the third motor while maintaining the lock of the second motor, and a step of executing the boring process of the work, and the above. After the boring process of the work is completed, the first motor is controlled, and the contact between the work and the tool is released while the lock of the second motor is maintained, and after the release step is completed, the above is performed. The third motor is controlled, and the step of pulling out the tool from the work is executed while the lock of the second motor is maintained.

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

It is a figure which shows an example of the device structure of a machine tool. It is a figure which shows the process of boring processing in chronological order. It is a figure which shows the process of boring processing following FIG. 2 in chronological order. It is a figure which shows the flow of the boring processing when the boring position at the time of the Nth boring processing and the boring position at the time of N + 1th boring processing are the same in the direction of gravity. It is a figure which shows the flow of the boring processing when the boring position at the time of the Nth boring processing and the boring position at the time of N + 1th boring processing are different in the direction of gravity. It is a schematic diagram which shows an example of the hardware composition of a CPU (Central Processing Unit) unit. It is a schematic diagram which shows an example of the hardware composition of the CNC (Computer Numerical Control) unit. It is a figure which shows an example of the functional structure of a machine tool. It is a flowchart which shows the flow of boring processing.

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

<A. Configuration of machine tool 10>
First, the apparatus configuration of the machine tool 10 will be described with reference to FIG. FIG. 1 is a diagram showing 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, another cutting machine, or a grinding machine. Typically, the machine tool 10 is a horizontal machining center on which tools are mounted horizontally.

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

The “control device 50” as used herein means a device that controls a machine tool 10. The device configuration of the control device 50 is arbitrary. The control device 50 may be composed of a single control unit or a plurality of control units. In the example of FIG. 1, the control device 50 is composed of 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 fieldbus B and communicate with each other via the fieldbus B.

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

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

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 by, for example, a ladder program.

The CNC unit 30 starts executing a machining program prepared in advance based on the 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 by, for example, an NC (Numerical Control) program.

The servo driver 111R sequentially receives input of a target rotation speed from the CNC unit 30 and controls the servo motor 112R (rotation drive unit). The servomotor 112R rotationally drives the spindle 132 around the axis in the Z direction. More specifically, the servo driver 111R calculates the actual rotation speed of the servo motor 112R from the feedback signal of an encoder (not shown) for detecting the rotation angle of the servo motor 112R, and the actual rotation speed is the target rotation speed. If it is smaller than, the rotation speed of the servomotor 112R is increased, and if the actual rotation speed is larger than the target rotation speed, the rotation speed of the servomotor 112R is decreased. In this way, the servo driver 111R brings the rotation speed of the servomotor 112R closer to the target rotation speed while sequentially receiving feedback of the rotation speed of the servomotor 112R.

The servo driver 111X sequentially receives input of the target position from the CNC unit 30 and controls the servo motor 112X (first motor). The servomotor 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 the feedback signal of the encoder (not shown) for detecting the rotation angle of the servomotor 112X, and the actual position is smaller than the target position. In this case, the actual position of the servomotor 112X is raised, and when the actual position is larger than the target position, the actual position of the servomotor 112X is lowered. In this way, the servo driver 111X brings the actual position of the servomotor 112X closer to the target position while sequentially receiving feedback of the actual position of the servomotor 112X. As a result, the servo driver 111X feeds and drives the spindle 132 to an arbitrary position in the X direction.

The servo driver 111Y sequentially receives input of the target position from the CNC unit 30 and controls the servo motor 112Y (second motor). The servomotor 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. Since the method of controlling the servomotor 112Y by the servo driver 111Y is the same as that of the servo driver 111X, the description thereof will not be repeated.

The servo driver 111Z sequentially receives input of the target position from the CNC unit 30 and controls the servo motor 112Z (third motor). The servomotor 112Z 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 Z direction. Since the method of controlling the servomotor 112Z by the servo driver 111Z is the same as that of the servo driver 111X, the 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 to lock the feed drive of the servomotor 112Y for the gravity direction and unlock the servomotor 112Y. The brake mechanism 110 is, for example, an electromagnetic brake, an electromagnetic clutch, or other hard mechanism capable of locking the feed drive of the servomotor 112Y. When the brake mechanism 110 locks the feed drive of the servomotor 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 work W with respect to the boring tool 134 by feeding and driving the spindle 132 has been described. However, the machine tool 10 is a fixing device for the work W. The relative position may be changed by feeding and driving the table 136, or the relative position may be changed by feeding and driving both the spindle 132 and the table 136. That is, the servomotor 112X may be configured to feed and drive the spindle 132 in the X direction, or may be configured to feed and drive the table 136 in the X direction. The servomotor 112Y may be configured to feed and drive the spindle 132 in the Y direction, or may be configured to feed and drive the table 136 in the Y direction. The servomotor 112Z may be configured to feed and drive the spindle 132 in the Z direction, or may be configured to feed and drive the table 136 in the Z direction.

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

In step S1, the control device 50 of the machine tool 10 unlocks the servomotor 112Y by the brake mechanism 110 so that the spindle 132 can be fed and driven in the direction of gravity (Y direction). After that, the control device 50 controls the servomotors 112X and 112Y, and feeds and drives the boring tool 134 in the XY directions. As a result, 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 the predetermined machining start position. Based on this, the control device 50 controls the brake mechanism 110 and locks the feed drive of the servomotor 112Y. As a result, the boring tool 134 becomes immobile in the direction of gravity (Y direction).

In step S3, the control device 50 controls the servomotor 112R and the servomotor 112Z while maintaining the lock of the servomotor 112Y, and executes the boring process of the work W. As a result, the boring tool 134 digs the work W in the Z direction while rotating.

It is assumed that the boring process for the work W is completed in step S4. The term "completion of boring" as used herein means that the formation of one inner diameter (hole) has been completed. Since the blade of the boring tool 134 protrudes from the tool shaft, only the blade portion is in contact with the work W when the boring process is completed. In order to eliminate this contact, it is necessary to feed and drive the boring tool 134, but since the feed drive in the Y direction (gravity direction) is locked, the control device 50 only feeds and drives in the X direction. The contact between the boring tool 134 and the work W is eliminated. That is, the control device 50 controls the servomotor 112X after the boring process 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 feeds and drives the servomotor 112X in the direction in which the blade of the boring tool 134 is separated from the inner diameter surface of the work W.

Depending on the specifications, 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 work W is not eliminated only by feeding and driving the boring tool 134 in the X direction. Therefore, when the blade of the boring tool 134 is oriented in the Y direction (gravity direction), the control device 50 directs the blade of the boring tool 134 in a direction different from the Y direction (gravity direction), and then, The boring tool 134 is fed and driven in the X direction to eliminate the contact between the boring tool 134 and the work 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 toward the negative side in the X direction, and then moves the boring tool 134 to the positive side in the X direction. As a result, the contact between the boring tool 134 and the work 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 work W while maintaining the lock of the servomotor 112Y.

As described above, when the boring process is completed, the control device 50 feeds and drives the boring tool 134 in the X direction to eliminate the contact between the work W and the boring tool 134. This eliminates the need to unlock the servomotor 112Y when the boring tool 134 is pulled out of the work W. As a result, the machine tool 10 can shorten the machining time and can surely prevent the boring tool 134 from falling due to a power failure or an error.

Further, since the boring tool 134 is pulled out from the work W after the contact between the boring tool 134 and the work W is eliminated, the boring tool 134 does not damage the work W and the boring tool 134 is prevented from being damaged. It comes off.

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

FIG. 4 is a diagram showing a flow of boring processing when the boring position at the time of the Nth boring processing and the boring position at the time of the N + 1th boring processing 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 work W is completed and the Nth boring process is completed. In the example of FIG. 4, a hole is formed at the machining position P of the work W by the Nth boring process.

It is assumed that the processing program stipulates that boring processing should be continued. In this case, the control device 50 acquires the next machining position PX (coordinate value) from the machining program, and sets the machining position P at the Nth boring machining and the machining position PX at the N + 1th boring machining in the direction of gravity. Compare with respect to (Y direction). In this example, it is assumed that the machining position P and the machining position PX are the same in the direction of gravity. In this case, in step S12, the control device 50 aligns the boring tool 134 only in the X direction while maintaining the locked state of the servomotor 112Y.

After that, in step S13, the control device 50 starts the N + 1th boring process to form a hole at the processing position PX of the work W.

As described above, the control device 50 sets the previous machining position of the work W and the work before the process of pulling out the boring tool 134 from the work W and before the start of the next boring of the work W. When the next machining position of W is the same in the direction of gravity, the locked state of the servomotor 112Y by the brake mechanism 110 is maintained. As a result, the control device 50 does not have to unlock the brake mechanism 110 when moving from the Nth boring process to the N + 1th boring process, and the processing time can be shortened.

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

It is assumed that in step S21, the process of pulling out the boring tool 134 from the work W is completed, and the Nth boring process is completed. In the example of FIG. 5, a hole is formed at the machining position P of the work W by the Nth boring process.

It is assumed that the processing program stipulates that boring processing should be continued. In this case, the control device 50 acquires the next machining position PY (coordinate value) from the machining program, and sets the machining position P at the Nth boring machining and the machining position PY at the N + 1th boring machining in the direction of gravity. Compare with respect to. In this example, it is assumed that the machining position P and the machining position PY are different in the direction of gravity. In this case, the control device 50 unlocks the servomotor 112Y.

After that, in step S22, the control device 50 aligns the boring tool 134 in the X direction and the Y direction. The control device 50 locks the feed drive of the servomotor 112Y again based on the completion of the alignment.

After that, in step S23, the control device 50 starts the N + 1th boring process to form a hole at the processing position PY of the work W.

As described above, the control device 50 sets the previous machining position of the work W and the work before the process of pulling out the boring tool 134 from the work W and before the start of the next boring of the work W. When the next machining position of W is different in the direction of gravity, the locked state of the servomotor 112Y by the brake mechanism 110 is released. As a result, the control device 50 can arbitrarily change the boring position in the direction of gravity when shifting from the Nth boring process to the N + 1th boring process.

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

The CPU unit 20 includes a processor 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, a communication interface 54, a fieldbus controller 55, and a storage device 70. These components are connected to the internal bus 59.

The processor 51 is composed of, for example, at least one integrated circuit. The integrated circuit is, 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 them. It may be composed of a combination of.

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 instructions 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 into 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.

A LAN (Local Area Network), an antenna, or the like is connected to the communication interface 54. 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 so that the PLC program 72 can be downloaded from the external device.

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

The storage device 70 is, for example, a storage medium such as a hard disk or a flash memory. The storage device 70 stores the 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 of the processor 51 (for example, a cache memory), a ROM 52, a RAM 53, an external device (for example, a server), or the like.

<E. Hardware configuration of CNC unit 30>
Next, the hardware configuration of the CNC unit 30 will be described with reference to FIG. 7. FIG. 7 is a schematic view showing an example of the 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 composed of, for example, at least one integrated circuit. An integrated circuit may consist of, 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 the machining program 122 (control program). The machining program 122 defines various instructions for realizing machining of the workpiece. The processor 101 reads the machining program 122 from the storage device 120 or the ROM 102 into the RAM 103 based on the reception of the execution instruction of the machining program 122. The RAM 103 functions as a working memory and temporarily stores various data necessary for executing the machining program 122.

A LAN, an antenna, or the like is connected to the communication interface 104. 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 so that the machining program 122 can be downloaded 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 fieldbus 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 the machining program 122 and the like. The storage location of the processing program 122 is not limited to the storage device 120, and may be stored in a storage area of the processor 101 (for example, a cache memory), a ROM 102, a 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 stand-alone program. In this case, the machining process by the machining program 122 is realized in cooperation with an arbitrary program. Even a program that does not include such a part of the modules does not deviate from the purpose of the machining program 122 according to the present embodiment. Further, some or all of the functions provided by the machining program 122 may be realized by dedicated hardware. Further, the machine tool 10 may be configured in the form of 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 showing an example of the 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 configurations. The control device 50 is composed of, for example, a CPU unit 20 and a CNC unit 30.

The rotation drive unit 160 is a mechanism for controlling the rotation of the spindle 132 (see FIG. 1). As an example, the rotation drive unit 160 includes the above-mentioned servo driver 111R (see FIG. 1) and the above-mentioned servomotor 112R (see FIG. 1).

The position drive unit 162 is a mechanism for changing the relative position of the boring tool 134 with respect to the work by moving at least one position of the spindle 132 and the above-mentioned table 136 (see FIG. 1). As an example, the position drive unit 162 includes the above-mentioned servo drivers 111X to 111Z (see FIG. 1) and the above-mentioned servo motors 112X to 112Z (see FIG. 1).

The CNC unit 30 includes a machining control unit 152 and a brake control unit 154 as functional configurations.

The machining control unit 152 controls the servo drivers 111R, 111X to 111Z according to a predetermined machining program 122 to machine the workpiece.

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 in response to a command being executed by the machining program 122. To do. The lock command and the lock release command are input to, for example, the PLC program 72 in the CPU unit 20.

Further, when the machine tool 10 stops abnormally during the boring process of the work, the brake control unit 154 enables the lock of the brake mechanism 110 and maintains the lock of the servomotor 112Y which is responsible for the feed drive in the gravity direction. The abnormality to be detected is, for example, the occurrence of an earthquake or a power outage. An earthquake is detected, for example, based on the fact that the output value of an acceleration sensor mounted on the machine tool 10 exceeds a predetermined value. The power failure is detected by, for example, a power failure detection circuit mounted on the machine tool 10. By maintaining the lock of the servomotor 112Y when an abnormality occurs, it is possible to more reliably prevent the boring tool 134 from falling.

When the PLC program 72 receives 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. Due to the electromagnetic force, the brake is separated from the servomotor 112Y, and the servomotor 112Y can rotate.

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

<G. Flowchart related to boring process>
The flow of boring processing will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of boring processing.

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 machining program 122 (see FIG. 8) described above. In other aspects, some or all of the processing may be performed by circuit elements or other hardware.

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

More specifically, in step S110, in the control device 50, is the current position of the boring tool 134 and the machining position of the work W (that is, the boring position) at the time of the next boring machining the same in the direction of gravity? Judge whether or not. When the control device 50 determines that the current position of the boring tool 134 and the boring position at the time of the next boring process are the same in the direction of gravity (YES in step S110), the control device 50 switches the control to step S112. If not (NO in step S110), the control device 50 switches 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 it is not necessary for the control device 50 to feed and drive the boring tool 134 in the gravity direction (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 unlocks the servomotor 112Y by the brake mechanism 110 so that the spindle 132 can be fed and driven in the direction of gravity.

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 and locks the feed drive of the servomotor 112Y. As a result, the boring tool 134 becomes immobile 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 rotationally driving it. As a result, boring of the work is started.

It is assumed that the boring process of the work is completed in step S122. Based on this, the control device 50 feeds and drives the boring tool 134 in the X direction by controlling the servomotor 112X, and eliminates the contact between the work W and the boring tool 134.

In step S124, the control device 50 controls the servomotor 112Z and pulls 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 to eliminate the contact between the work W and the boring tool 134. This eliminates the need to unlock the servomotor 112Y when the boring tool 134 is pulled out of the work W. As a result, the machine tool 10 can shorten the machining time and can surely prevent the boring tool 134 from falling due to a power failure or an error.

Further, since the boring tool 134 is pulled out from the work W after the contact between the boring tool 134 and the work W is eliminated, the boring tool 134 does not damage the work W and the boring tool 134 is prevented from being damaged. It comes off.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10 machine tools, 20 CPU units, 30 CNC units, 40 I / O units, 50 controls, 51,101 processors, 52,102 ROMs, 53,103 RAMs, 54,104 communication interfaces, 55,105 fieldbus controllers, 59,109 Internal bus, 70,120 storage device, 72 PLC program, 110 brake mechanism, 111R, 111X, 111Y, 111Z servo driver, 112R, 112X, 112Y, 112Z servo motor, 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)

It ’s a machine tool,
A spindle to which tools used for boring of workpieces can be attached,
A table for fixing the work and
A rotary drive unit for rotationally driving the spindle and
A position driving unit for changing the relative position of the tool with respect to the work by moving at least one position of the spindle and the table is provided.
The position drive unit
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,
Including a third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravity direction.
A brake mechanism for locking the drive of the second motor and
Further equipped with a control device for controlling the machine tool,
The control device is
A process of controlling the first motor and the second motor to move the tool to a predetermined machining start position, and
A process of controlling the brake mechanism and locking the drive of the second motor after the process of moving the tool to the machining start position is completed, and a process of locking the drive of the second motor.
A process of controlling the rotary drive unit and the third motor while maintaining the lock of the second motor to execute boring of the workpiece.
A process of controlling the first motor after the boring process of the work is completed and eliminating 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 process of eliminating the problem is completed, and executes a process of pulling out the tool from the work while maintaining the lock of the second motor. The control device further performs the previous machining position of the work and the next machining position of the work after the process of pulling out the tool from the work is completed and before the next boring of the work is started. The machine tool according to claim 1, wherein the process of unlocking the second motor is executed when the machining position is different in the direction of gravity. The control device further performs the previous machining position of the work and the next machining position of the work after the process of pulling out the tool from the work is completed and before the next boring of the work is started. The machine tool according to claim 1 or 2, wherein when the machining positions are the same in the direction of gravity, the process of maintaining the lock of the second motor is executed. According to any one of claims 1 to 3, the control device further executes a process of maintaining the lock of the second motor when the machine tool stops abnormally during the boring process of the work. The machine tool described. The control device executes a process of directing the blade of the tool in a direction different from the direction of gravity after the boring of the work is completed and before controlling the first motor. The machine tool according to any one of 4. It is a control method for machine tools.
The machine tool
A spindle to which tools used for boring of workpieces can be attached,
A table for fixing the work and
A rotary drive unit for rotationally driving the spindle and
A position driving unit for changing the relative position of the tool with respect to the work by moving at least one position of the spindle and the table is provided.
The position drive unit
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,
Including a third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravity direction.
A brake mechanism for locking the drive of the second motor is further provided.
The control method is
A step of controlling the first motor and the second motor to move the tool to a predetermined machining start position, and
A step of controlling the brake mechanism and locking the drive of the second motor after the moving step is completed, and a step of locking the drive of the second motor.
A step of controlling the rotary drive unit and the third motor while maintaining the lock of the second motor to execute boring of the work.
A step of controlling the first motor after the boring process of the work is completed and releasing the contact between the work and the tool while maintaining the lock of the second motor.
A control method comprising a step of controlling the third motor after the step of solving the problem is completed and pulling out the tool from the work while maintaining the lock of the second motor. A machine tool control program
The machine tool
A spindle to which tools used for boring of workpieces can be attached,
A table for fixing the work and
A rotary drive unit for rotationally driving the spindle and
A position driving unit for changing the relative position of the tool with respect to the work by moving at least one position of the spindle and the table is provided.
The position drive unit
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,
Including a third motor for changing the relative position in a direction orthogonal to both the horizontal direction and the gravity direction.
A brake mechanism for locking the drive of the second motor is further provided.
The control program is applied to the machine tool.
A step of controlling the first motor and the second motor to move the tool to a predetermined machining start position, and
A step of controlling the brake mechanism and locking the drive of the second motor after the moving step is completed, and a step of locking the drive of the second motor.
A step of controlling the rotary drive unit and the third motor while maintaining the lock of the second motor to execute boring of the work.
A step of controlling the first motor after the boring process of the work is completed and releasing the contact between the work and the tool while maintaining the lock of the second motor.
A control program that controls the third motor after the step of solving the problem is completed, and executes a step of pulling out the tool from the work while maintaining the lock of the second motor.

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