JP6159578B2 - How to operate machine tools - Google Patents

Description

  The present invention relates to a method for operating a machine tool, in particular, a lathe equipped with a hydraulic chuck, and relates to an operation method for avoiding wasteful power consumption and an increase in machine temperature.

  Normally, NC machine tools are automatically operated in accordance with a machining program, but are manually operated when performing machine operation confirmation, test machining, machining program operation confirmation, and the like. For manual operation, pure manual operation that specifies the cutting depth and feed rate from the keyboard of the operation panel for each commanded operation, or operation for each step or block of the machining program every time the switch on the operation panel is pressed. There is also a manual operation that can be said to be semi-automatic, but in any manual operation, when the operation started by the switch on the operation panel is completed, the machine waits in a stopped state until the next operation command is received.

  The machine or the NC device does not recognize whether the operator is in front of the operation panel, and cannot recognize the intention of the operator even if a camera or the like is installed to recognize the presence or absence of the operator. For example, when an operator commands a certain operation from the operation panel and performs an operation to change a parameter (constant) set in the machine or machining program from the operation result, the machine waits for a long time with the machine stopped. Things happen.

  At the time of this standby, the power of the machine and the NC device is turned on, but the spindle motor, the feed motor of the tool post, etc. are stopped, so little power is consumed. On the other hand, some machine tools are driven by hydraulic pressure, such as opening and closing a chuck and fixing a turret index position. In many cases, the hydraulic drive system operates a cylinder and a plurality of other hydraulic actuators independently by the hydraulic pressure generated by one hydraulic pump, but the hydraulic pump is driven even when all the hydraulic actuators are stopped. In general, the pump motor is kept rotating to maintain a constant hydraulic pressure. Therefore, in a machine tool equipped with a hydraulic drive system, electric power is consumed by the pump motor even when the machine is stopped, and the oil temperature rises by circulating oil while being pressurized.

  As described above, during manual operation, there is always a situation in which the machine waits for an input of an operation command from the operator, and the operator waits in a stopped state, so that the operator can calculate parameters or change settings for the next operation. It may happen that the machine is stopped for a long time because it takes time and makes a meeting with the creator of the machining program to check whether the machine operation is correct.

  Therefore, when the machine is stopped for such a long period of time, the hydraulic pump that continues to consume power during the stoppage is stopped to save energy and to prevent the temperature of the hydraulic oil from rising due to thermal deformation of the machine. Can be considered.

  However, in a machine tool that grips and processes a workpiece with a spindle chuck like a lathe and uses a hydraulic chuck that hydraulically opens and closes the chuck, when the hydraulic pump is stopped, the hydraulic chuck is gripped. Since the force has a frictional resistance such as a piston, even if the force does not become zero, the force is greatly reduced, the workpiece is displaced and the gripping accuracy cannot be maintained, or the workpiece is dropped from the chuck. This is not a problem if it is a manual operation that simply confirms the operation of the machine, but in a manual operation that checks the cutting conditions and machining program while actually machining the workpiece, the hydraulic pressure is applied during the machining of the workpiece. Since the pump has stopped, the workpiece is displaced or dropped, making it impossible to perform further machining, or when the hydraulic pump is moved again, the workpiece is gripped in a state of deviating from the original posture, and the subsequent machining operation is confirmed correctly. The problem that it becomes impossible to occur.

  In view of this, the present invention provides means for avoiding unnecessary power consumption and increase in machine temperature while the machine in manual operation is stopped, and preventing occurrence of the above-described problems in a machine tool having a hydraulic chuck. The issue is to provide.

  In the present invention, in a manual operation of a machine tool having a hydraulic drive system including the hydraulic chuck 3, only when the chuck 3 is not closed, after the set time counted by the timer 15 has elapsed without operating the machine. Thus, by stopping the hydraulic pump 5, wasteful power consumption and an increase in machine temperature are prevented without causing a decrease in gripping force of the chuck 3 or a shift in the posture of the workpiece due to the stop of the hydraulic pump.

  Specifically, the NC device 1 of the machine tool having a hydraulic drive system including the hydraulic chuck 3 is provided with a timer 15, a setting device 14 for setting the time measurement completion time of the timer, and a hydraulic pump when the timer time measurement is completed. Stop means 18 for stopping and timer reset means 16 are provided. When the machine is operated in the manual operation mode, when the machine has the energy saving operation mode (hydraulic pump off function is on) and the normal operation mode (hydraulic pump off function is off), the machine is in the manual operation mode and When operating in the energy saving operation mode, the timer 15 performs a time counting operation. When the time of the timer 15 reaches the time set in the setting device 14, the pump motor 6 driving the hydraulic pump 5 is provided on the condition that the machine is not operating and the hydraulic chuck 3 is not closed. Turn off the power. The timer 15 is reset when a command signal for some machine operation is received.

  Since the hydraulic pump 5 does not stop when the hydraulic chuck 3 is closed, the gripping force of the chuck does not decrease when the hydraulic chuck 3 is gripping the workpiece w, and a shift in the position and posture of the workpiece can be prevented. On the other hand, when the hydraulic chuck 3 is not gripping the workpiece w, the hydraulic pump 5 is stopped when the time set in the NC device has elapsed without performing any mechanical operation, and the power consumption of the pump motor 6 is eliminated. Since the temperature of the hydraulic oil does not rise, energy saving and thermal deformation of the machine can be reduced.

  The open / close state of the hydraulic chuck can use the signal of the existing proximity sensor 33 provided in the chuck cylinder 31 that opens and closes the hydraulic chuck, so there is no need to add new equipment, and energy and heat can be saved at no cost. It is possible to prevent deformation.

The block diagram which shows an example of the apparatus which implements this invention The flowchart which shows an example of the procedure which implements the method of this invention

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing an apparatus for carrying out the method of the present invention using an NC lathe as an example. In the figure, an NC device 1 for controlling the machine, a spindle chuck 3 which is a machine-side device, a turret tool post 4, a hydraulic pump 5 and a pump motor 6, and a switch 61 thereof are shown.
The spindle chuck 3 for gripping the workpiece w is a hydraulic chuck attached to the tip of the spindle supported by the spindle table 35 and is opened and closed by a chuck cylinder 31 attached to the rear end of the spindle. The chuck cylinder 31 is provided with a proximity sensor 33 for detecting the closed state of the chuck.

  The turret tool post 4 incorporates a short stroke cylinder for fixing the indexing position of the turret 41, and fixing the indexing position of the turret 41 and an indexing motor by fitting and detaching the face coupling with the cylinder. The state in which the turret 41 can be rotated by 42 is switched.

  The hydraulic pressure of the hydraulic pump 5 is supplied to the chuck cylinder 31 and the index position fixing cylinder of the turret tool post 4 via the pressure setting valve 51 and the switching valves 52 and 53. The hydraulic circuit in the figure is shown in a simplified manner, and an oil tank and a return pipe to the oil tank are omitted. The pump motor 6 that rotationally drives the hydraulic pump 5 is turned on / off (rotated / stopped) by a switch 61.

  Note that the hydraulic pressure of the hydraulic pump 5 may be supplied to other devices. For example, in a machine equipped with a plurality of spindle chucks and a plurality of turret tool posts, a plurality of chuck cylinders and turret fixing cylinders are respectively provided. It is connected to the hydraulic circuit shown in the figure via a switching valve.

  The NC device 1 includes an operation panel 2, a PC (programmable controller) unit 11, a machining program 12, and an NC unit 13. The operation panel 2 is provided with a display 21, an operation mode changeover switch 22, a numeric keypad 23, a manual operation switch 24 corresponding to each drive device of the machine, and the like. The operation mode switch 22 is a switch for switching between manual operation, step feed operation of a machining program, automatic operation, and the like. The numeric keypad 23 is used to set various parameters (for example, the rotation speed and rotation angle of the spindle, the feed rate of the tool post, and the timer setting time) set for the machine.

  The PC unit 11 controls the sequential operation of the machine, and when the start condition of each operation such as the end of the previous operation is completed, an automatic operation of the machine is given by giving an operation command to the drive source of the operation. Is controlling the sequential behavior. During manual operation, when the operator operates the corresponding operation switch in a state where the operation start conditions are in place, the commanded operation is started in response to the signal. For each input signal including operation of the operation switch, the PC unit can set an operation to be performed when the signal is input, together with a condition for permitting the operation. The above devices and functions are generally provided conventionally.

  An NC apparatus 1 preferable for carrying out the present invention is provided with an energy saving mode changeover switch 25 for switching between a normal operation mode and an energy saving operation mode. The NC device 1 includes an operation waiting time setter 14 for setting a time for waiting for the next operation signal while operating the hydraulic pump 5 during manual operation, a timer 15 for measuring the time, and a reset means 16 for the timer. The comparator 17 that outputs a timing completion signal a when the timer timing is completed, that is, when the timer 15 exceeds the time set in the setting device 14, and the timing completion signal a and the proximity sensor 33 of the chuck cylinder Is provided with a pump stop means 18 for providing a shut-off signal c to the switch 61 of the pump motor 6 under an AND condition with the signal b that the chuck is not closed.

  The timer reset means 16 is formed by using the function of the PC unit 11, and the operation signal of the machine operation switch 24 (including the step feed switch of the machining program) excluding the numeric keypad 23 and the mode change-over switches 22 and 25. Is formed by adding a reset operation of the timer 15 to the operation when the timer is received.

  The timer 15 starts timing when manual operation in the energy saving mode is started. When any one of the operation switches 24 is operated at an interval not exceeding the time set in the setting device 14, the timer 15 is reset for each operation, so that the operation is continued without stopping the hydraulic pump 5. The

  During manual operation, when the operator sets or changes parameters to be set in the machine using the numeric keypad 23 and the time until the next operation switch is operated becomes longer, the time is set in the setting device 14. When the set time is exceeded, the switch 61 of the pump motor 6 is turned off on the condition that the spindle chuck 3 is not closed, and the hydraulic pump 5 is stopped. Even if the time measured by the timer 15 is longer than the time set by the setting device 14, if the chuck closing signal is output from the proximity sensor 33 of the chuck cylinder, the hydraulic pump 5 does not stop, so that the gripping force of the chuck 3 is increased. There is no loss.

  When any one of the operation switches 24 is operated while the hydraulic pump 5 is stopped, the timer 15 is reset and the timing completion signal is turned off, so that the operation of the hydraulic pump 5 is automatically resumed.

  FIG. 2 is a diagram showing an example of a procedure when the present invention is realized by software. In the hydraulic pump on state in which the hydraulic pump 5 is driven, whether the hydraulic pump off function is valid or invalid, that is, It is determined whether the energy saving operation mode in the above description is valid or invalid, and if it is not the energy saving mode, the hydraulic pump on state is continued. If it is in the energy saving mode, it is checked whether or not the operation switch is operated or the handle is operated, and when there is an operation, the timer 15 is reset and the hydraulic pump is turned on. When there is no operation, the hydraulic pump is turned off on condition that the spindle chuck is not closed and the timer has elapsed. When these two conditions are not satisfied, the hydraulic pump is kept on.

  As can be understood from the above embodiments, according to the present invention, it is possible to avoid wasteful power consumption and increase in hydraulic temperature due to the hydraulic pump being operated for a long time without manual operation during manual operation. In addition, the hydraulic pump stops while the spindle chuck is holding the workpiece, the workpiece grip is loosened and the workpiece gripping accuracy is reduced, or the workpiece is dropped from the spindle chuck, and then manual operation is performed. There is an effect that it is possible to prevent the problem that is not performed correctly.

DESCRIPTION OF SYMBOLS 1 NC apparatus 3 Hydraulic chuck 5 Hydraulic pump 6 Pump motor 14 Operation wait time setting device 15 Timer 16 Timer reset means 18 Pump stop means

Claims (2)

Energy saving operation method for machine tool comprising chuck closing detection means for detecting closed state of hydraulic chuck holding workpiece and manual operation mode for operating machine to be operated in response to machine operation signal from operation panel In
A timer for measuring the operation waiting time, a setter for setting the time measurement completion time of the timer, and a timer reset means for resetting the timer when any machine operation signal is output from the operation panel,
Provided that the timer completes timing when the machine is operating in manual operation mode, that the machine is stopped, and that the chuck closing detection means has not detected chuck closing. An operation method for a machine tool that stops the hydraulic pump and starts the operation of the hydraulic pump when any machine operation signal is output from the operation panel.   An energy saving manual operation mode, a normal manual operation mode, and an automatic operation mode are provided, and the method according to claim 1 is executed when operating in the energy saving manual operation mode, and the hydraulic pump is stopped. A method for operating a machine tool, wherein operation of the hydraulic pump is started even when a mode switching signal for switching modes is received.

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