JP3976414B2 - Thermostatic device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermostatic device that is applied to a high-precision machine and controls the temperature of a machining fluid to a set temperature.
[0002]
[Prior art]
In general, the installation of air-conditioning equipment in a vast machining factory requires a huge amount of equipment and consumes a large amount of power, so that a general machining factory has few air-conditioning equipment. The room temperature of a factory without air conditioning equipment changes from morning to night in the day, and also changes due to changes in the seasons, and the daily and annual changes in room temperature are extremely large. The work machine itself as well as the work machine itself undergoes thermal expansion and contraction due to this temperature difference. Therefore, when high-precision machining is required for the work piece, this temperature difference cannot be ignored.
[0003]
Therefore, in order to achieve high-precision machining, conventionally, a thermostatic device for maintaining the temperature of the cutting fluid at a constant temperature is provided, and the cutting fluid adjusted to a constant temperature is set in the tool and the processing machine provided in the processing machine. In addition, the temperature of the workpiece or the like being processed does not change even if the ambient temperature changes by supplying the processed portion with the workpiece processed by the tool. From this point of view, the present applicant has also proposed a thermostat and a temperature control method for the thermostat (Japanese Patent Application No. 10-101924).
[0004]
The thermostat according to the above proposal is an automatic sensor that detects the temperature of the cutting fluid stored in the tank, a sensor that detects the ambient temperature, and the temperature detected by the sensor when the processing machine is started as the set temperature. An automatic temperature setter that automatically sets the temperature, and a temperature control device that adjusts the temperature of the cutting fluid so that the temperature detected by the fluid temperature sensor becomes the set temperature. The temperature control method of the apparatus is a constant temperature apparatus for maintaining the cutting fluid supplied to the processing machine at a set temperature in order to cool the workpiece, the cutting tool set in the processing machine, and the heat generating part in the processing machine. In this temperature control method, the ambient temperature at the start of machining is automatically detected by a sensor, the detected value is set as a set temperature, and the temperature is controlled so that the temperature of the cutting fluid is maintained at the set temperature. And it is characterized in and.
[0005]
The temperature control device proposed by the present applicant and the temperature control method of the temperature control device are such that when the processing machine is started, for example, when the start switch (power switch) is turned on at the beginning of the day, the ambient temperature, that is, the room temperature is automatically set. The temperature detected by the sensor is set as the set temperature of the constant temperature device, and the controller controls to maintain the set temperature during machining, so that almost no waiting time is required at startup, and the machine itself and the workpiece It is intended to ensure high-precision machining of workpieces by eliminating temperature fluctuations during machining and deformation of the machine and workpieces based on it.
[0006]
Since the temperature of the cutting fluid normally matches the room temperature at the initial start-up of the processing machine, there is no need to wait until the temperature of the cutting fluid matches the set temperature. When the temperature of the cutting fluid detected by the fluid temperature sensor deviates from the set temperature, the temperature control device cools or heats the cutting fluid stored in the tank so that the temperature of the cutting fluid matches the set temperature. Make adjustments. The cutting fluid maintained at the set temperature is supplied to the processing machine, and cools the workpiece, the cutting tool, and the heat generating part in the processing machine set in the processing machine. As a result, the temperature of the workpiece and the tool is kept constant without being affected by the ambient temperature change, thereby enabling high-precision machining.
[0007]
The above thermostat and the temperature control method of the thermostat are effective for suppressing a reduction in machining accuracy at the initial startup of the machine, but the machine must be turned off due to some trouble. When a problem arises, the temperature of the machining fluid is started with the same control procedure as at startup when the trouble is solved and the power is turned on next time. That is, as shown in FIG. 5, the machine of the time of initial startup and t _0, at room temperature from the processing start, in a general factory environment that varies as T _R, at t ₁ the initial start-up during and after continuous processing If any trouble such as off the power supply was restarted at again t _2, in the prior art, to set the room temperature T _{R 2} at the time of re-starting the set temperature T _S, the set temperature T _S (= T _{R 2} ), The temperature of the machining fluid is controlled, and the temperature T _{L of the} machining fluid draws a curve of T _{L 1} (memory function off). Similarly, the processing dimension also draws a line of T _{L 1} (lower part of FIG. 5), and gradually changes, and greatly differs from the initial processing dimension. Until the machine power is turned off, the machining fluid temperature is controlled at the initial set temperature T _{R 0} (= T _S ), which is largely different from the room temperature when the power is turned off. Even after the power is turned off, the machining fluid has a large heat capacity, so it cannot reach the same level as room temperature in a short time. If the machining dimensions become stable after restarting, correction can be made with an NC (numerical control) offset mechanism, but it takes Δt _{2 to} stabilize. Therefore, when the machine is restarted, the idling time of the machine of Δt ₂ occurs, and after that, a dimension check must be performed and offset correction must be performed, which causes unnecessary work and a reduction in the operating rate of the processing machine.
[0008]
[Problems to be solved by the invention]
Therefore, in the thermostatic device and its temperature control method, when the machine power is turned off and then restarted, the set temperature of the machining fluid temperature control is uniformly set to the room temperature detected at the time of restart. Instead, pay attention to the fact that the temperature change of the machining fluid is slow, and set the machining fluid temperature to be approximately equal to the temperature of the machining fluid when the machine power is turned off. There is a problem to be solved in that the workpiece can be machined with high machining accuracy immediately after returning.
[0009]
[Means for Solving the Problems]
An object of the present invention is to solve the above-mentioned problem, and to cope with a slow change in the temperature of the working fluid when the power is turned off and then restarted after the processing machine is initially started. Thus, by resetting the set temperature of the machining fluid temperature control to the set temperature when the machine power is turned off, the workpiece can be maintained with high machining accuracy immediately after the machine power is turned on. It is to provide a thermostatic device that can resume the processing and improve the operating rate of the processing machine.
[0010]
The present invention provides a liquid temperature sensor for detecting the temperature of the machining liquid, an air temperature sensor for detecting the ambient temperature, and the ambient temperature detected by the air temperature sensor as the set temperature of the machining liquid and the set value A controller for controlling the temperature of the machining fluid using the temperature as a target value, the controller storing the set temperature of the set machining fluid in a temperature memory, and the temperature sensor detects when the processing machine is restarted The present invention relates to a thermostatic device that can set a temperature read from the temperature memory instead of the ambient temperature as a new set temperature.
[0011]
According to this constant temperature device, the controller sets the ambient temperature detected by the air temperature sensor at the initial startup of the processing machine as the set temperature of the processing liquid, and controls the temperature of the processing liquid using the set temperature as a target value. . The set temperature of the set working fluid is arbitrarily stored in the temperature memory as the set temperature. When the machine is stopped by turning off the power to deal with any trouble, and the machine is started again after the trouble is resolved, the controller reads from the temperature memory instead of the ambient temperature detected by the temperature sensor. The temperature can be set as a new set temperature. The ambient temperature of the processing machine may change greatly during a short period of time from when the machine is stopped until it is restarted. However, since the machining fluid has a large heat capacity, the temperature of the machining fluid is not so high. It does not change. Therefore, by setting the set temperature before operation stop stored in the temperature memory as a new set temperature, the temperature of the machining fluid, the processing machine, etc. does not fluctuate greatly, it does not create a long standby time and is high. Processing accuracy is maintained.
[0012]
Storage of the set temperature of the working fluid in the temperature memory is performed when the start switch of the processing machine is turned off. Further, the machining fluid is supplied from the tank to the processing unit of the tool provided in the processing machine and the workpiece set on the processing machine and processed by the tool, and then is returned to the tank, so that the temperature of the machining fluid is increased. Is controlled by cooling or heating the working fluid stored in the tank.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a thermostat and a temperature control method for the thermostat according to the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing an embodiment of a thermostatic device according to the present invention, and FIG. 2 is an explanatory diagram for explaining the internal structure of the thermostatic device shown in FIG.
[0014]
The thermostatic device 1 is for managing the temperature of a machining fluid such as a cutting fluid stored for a processing machine such as a lathe at a predetermined temperature. As shown in FIGS. A liquid temperature sensor 4 for detecting the temperature of the machining liquid 3 stored in the chamber 4, an air temperature sensor 5 for detecting the room temperature, which is the ambient temperature, and a controller 6 for controlling the temperature of the machining liquid 3 to be a set temperature. Yes. The controller 6 includes a temperature setting unit 31 for setting the set temperature of the machining liquid 3 and a temperature control unit 32 for adjusting the temperature of the machining liquid 3 so that the temperature detected by the liquid temperature sensor 4 becomes the set temperature. ing.
[0015]
The thermostat 1 also includes a U-shaped heater 7 for heating the machining liquid 3 and a refrigeration apparatus 8 for cooling the machining liquid 3. Most of the refrigeration apparatus 8 excluding the cooler 9 and the controller 6 are accommodated in a case 10 of the thermostatic apparatus 1. On the other hand, the cooler 9, the heater 7, the liquid temperature sensor 4, and the stirring disk 11 of the refrigeration apparatus 8 protrude from the lower side of the case 10. The thermostatic device 1 is installed on the tank 2 containing the machining liquid 3 in a state in which the protruding devices 4, 7, 9, and 11 are immersed in the machining liquid 3. The air temperature sensor 5 is installed at an arbitrary position in the processing machine or the vicinity thereof so that the room temperature can be optimally detected. That is, the air temperature sensor 5 can be installed at an arbitrary place in the processing machine in order to detect the temperature of a desired region. In addition, the thermostatic device 1 is provided with a temperature memory 33 that stores the set temperature of the machining fluid set by the temperature setting unit 31 in association with the controller 6.
[0016]
As shown in FIG. 2, the refrigeration apparatus 8 includes a refrigeration cycle in which a compressor 12, a condenser 13, a capillary tube 14, and a cooler 9 are sequentially connected. In this refrigeration cycle, a bypass path 16 is provided to connect the discharge side and the suction side of the compressor 12 via an unloader solenoid valve 15, and the unloader solenoid valve 15 is a pressure switch (see FIG. (Not shown) and opens when the compressor 12 starts, and closes when the compressor 12 reaches a predetermined rotational speed and the pressure reaches a predetermined pressure. An accumulator 17 is provided on the suction side of the compressor 12 in order to prevent liquid back to the compressor 12. In addition, a filter 18 containing a desiccant is provided between the condenser 13 and the capillary tube 14 in order to remove foreign substances and moisture in the refrigerant.
[0017]
The refrigerant is compressed by the compressor 12 along with the rotation of the compressor 12, becomes a high-temperature and high-pressure gas refrigerant, and is discharged from the compressor 12 and enters the condenser 13. The condenser 13 is deprived of heat and the refrigerant is liquefied to become a high-temperature and high-pressure liquid refrigerant. Further, the fan 19 provided in the capacitor 13 functions to promote the condensation in the capacitor 13 by sending air to the capacitor 13. The high-temperature and high-pressure liquid refrigerant liquefied by the condenser 13 expands to become a low-temperature and low-pressure liquid refrigerant when passing through the capillary tube 14. The liquid refrigerant becomes a low-temperature and low-pressure gas refrigerant by taking heat away from the surroundings when passing through the cooler 9. That is, since the cooler 9 is immersed in the machining liquid 3, the machining liquid 3 is cooled by removing heat from the machining liquid 3. The cooler 9 is spirally wound and formed in a cylindrical shape, and a stirring disk 11 is provided in the cooler 9. The agitation disk 11 is driven by an agitation motor 21 to agitate the machining liquid 3 and make the temperature distribution in the tank 2 uniform.
[0018]
The heater 7 heats the machining fluid 3 and is provided with an airing prevention switch 20 in order to prevent airing. When the working fluid 3 in the tank 2 is insufficient, the airing prevention switch 20 is activated and the heater 7 is deactivated, and an alarm lamp (not shown) provided on the operation panel 22 is lit to cause an abnormality. Configured to inform.
[0019]
The liquid temperature sensor 4 immersed in the processing liquid 3 in the tank 2 and the air temperature sensor 5 for detecting the room temperature are connected to the controller 6, and the detected temperature detected by each sensor 4, 5 is the temperature controller. 6 is input. The room temperature detected by the temperature sensor 5 is configured to be input to the controller 6 when a start switch (power switch; not shown) of a processing machine (not shown) is turned on. For example, when the processing machine is started up at the beginning of the day, the room temperature detected by the temperature sensor 5 and input to the controller 6 is set as a set temperature in the temperature setting unit 31. Further, at the time of this setting or when turning off the power of the processing machine, the controller 6 arbitrarily stores the set temperature set in the temperature setting unit 31 at that time in the temperature memory 33.
[0020]
The temperature control unit 32 of the controller 6 controls the heater 7 or the refrigeration apparatus 8 so as to adjust the temperature so that the temperature of the machining liquid 3 detected by the liquid temperature sensor 4 matches the set temperature. The temperature of the working fluid 3 is always controlled to be substantially equal to the set temperature even if the room temperature changes. Then, the temperature-adjusted machining fluid 3 is supplied to the machining section in order to cool the machining section between the workpiece set on the machining machine and the tool provided on the machining machine and machining the workpiece. In other words, the machining fluid may be supplied to the processing machine in order to cool other heat generating parts in the processing machine.
[0021]
Next, the operation of the thermostatic device 1 according to the present invention will be described with reference to the flowcharts shown in FIGS. 3 and 4 and the graph shown in FIG. The flowchart shown in FIG. 3 is a flow showing the temperature setting process of the machining fluid when the start switch is on, and the flowchart shown in FIG. 4 is a flow showing the set temperature storing process when the start switch is off. The upper part of FIG. 5 is a graph showing the change over time of the ambient temperature T _R and the temperature T _L of the machining fluid, and the lower part is a graph showing the change in the machining dimension associated therewith. As shown in the flowchart of FIG. 3, first, when starting the operation of the processing machine at the beginning of the day, the operator turns on the start switch at time t ₀ (step 1). Next, it is determined whether or not the set temperature memory function is selected (step 2). For example, at the start of the processing machine at the beginning of the day (initial start-up), the set temperature memory function is turned off, so the controller 6 reads the room temperature T _{R 0} detected by the temperature sensor 5 at the present time (step 3). The read room temperature T _{R 0} is set as the set temperature T _S in the temperature setting unit 31 (step 4). When the set temperature T _S is set in the temperature setting unit 31, the process shifts to the processing liquid temperature control in the temperature control unit 32 (step 5).
[0022]
In the temperature control of the processing liquid in the temperature control unit 32, the controller 6 operates the heater 7 or the cooler 9 with the set temperature T _S set in the temperature setting unit 31 as a target value, and the liquid temperature sensor 4 For example, feedback control is performed so that the detected temperature T _L of the machining fluid 3 matches the set temperature T _S. Since the temperature T _L of the machining liquid 3 is usually equal to the room temperature T _R at the initial start-up of the processing machine, the set temperature T _S is equal to the temperature T _L of the machining liquid as shown in FIG. Accordingly, the processing machine can be operated immediately without requiring a waiting time after the processing machine is started.
[0023]
When machining on the workpiece is started by the processing machine, the machining fluid 3 in the tank 2 is supplied to the machining section of the workpiece and the tool and other heat generating sections in the machining machine, and the machining of the workpiece is performed while cooling them. Done. With the processing or with the change in room temperature T _R, but deviates from the machining fluid 3 in liquid temperature T _L is set by changing the temperature in the tank 2 arises, the liquid temperature sensor 4 of the working fluid 3 solution temperature since the T _L type always detect the controller 6, the temperature control unit 32 of the controller 6 performs control detected liquid temperature T _L is equal to the set temperature T _S. That is, when the liquid temperature T _L is lower than the set temperature T _S , the heater 7 is energized to heat the machining liquid 3, and when the liquid temperature T _L is higher than the set temperature T _S , the refrigeration apparatus 8 is operated. Then, the machining liquid 3 is cooled. Further, in order to accurately detect the liquid temperature _TL of the machining liquid 3, the stirring disk 11 is constantly driven by a stirring motor 21 so that the temperature distribution of the machining liquid 3 in the tank 2 is uniform. In this way, temperature control by feedback is performed so that the temperature of the machining fluid 3 matches or maintains the set temperature T _S. Therefore, as shown in FIG. 5, even if the room temperature T _R changes, the temperature of the machining fluid 3 is always maintained at the set temperature T _S , so that the workpiece and the tool are not affected by the change in the room temperature. The workpiece is maintained at the same temperature as the set temperature T _S and the workpiece is machined with high accuracy.
[0024]
When the start switch is turned off at time t ₁ due to some trouble occurring in the processing machine, such as during the processing of a workpiece by the processing machine, any processing is performed according to the flowchart for storing the set temperature shown in FIG. The set temperature for the machining fluid is stored in the temperature memory. That is, when the start switch is turned off, an interruption process is executed for the temperature control of the machining fluid by the controller 6, and the process proceeds to the process shown in FIG. When the start switch is turned off (step 10), it is determined whether or not the set temperature memory function is selected (step 11). When it is determined that the set temperature memory function is turned on, the controller 6 arbitrarily stores the set temperature T _S set in the temperature setting unit 31 in the temperature memory 33 (step 12), and then the thermostat 1 An instruction to shift the temperature control of the machining fluid to the stop process is issued (step 13). Further, when the operation of the processing machine is stopped for a certain long time, such as when the work of the day or a series of processing operations is completed, the set temperature memory function is turned off at step 11, so that the process proceeds to step 13. Skip and shift the temperature control of the machining fluid to the stop process. In this case, steps 1 to 5 are repeated at the next start-up.
[0025]
When the trouble of the processing machine is solved and the start switch is turned on again, in step 2 of the flowchart shown in FIG. 3, it is determined that the selection of the set temperature memory function is on. In this case, the controller 6 reads the temperature T _M stored in the temperature memory 33 (step 6), and resets the read temperature T _M as a new set temperature T _S in the temperature setting unit 31 (step 7). . Thereafter, the process proceeds to step 5 and the process temperature control similar to that described above is performed with the target set temperature T _S set when the start switch is turned off as a target (step 5).
[0026]
Therefore, when the start switch is turned on again, the ambient temperature TR ₂ detected by the temperature sensor 5 at the time of restart is not set as the set temperature, but is stored as the temperature TR _{0 in the} temperature memory 33. The set temperature when the start switch is turned off is read, and the temperature is set again as the set temperature T _S , so the amount of deviation from the temperature of the machining fluid decreases, and the temperature differs greatly from the set temperature. The machining fluid is not machined with the machining fluid, and the machining accuracy is deteriorated. The temperature of the machining fluid is set to a set temperature (= TR ₂ ) as indicated by an imaginary line in FIG. There is no need to wait for a match, and the machine can be operated immediately with good machining accuracy.
[0027]
【The invention's effect】
Since the thermostat according to the present invention has the configuration described above, it has the following effects. That is, according to the present invention, at the time of restarting, it becomes possible to read the set temperature when the start switch is turned off stored in the temperature memory and set it as a new set temperature. Even if it is significantly different from the ambient temperature at the initial start-up, the ambient temperature is not set as the set temperature, and a new temperature is set that approximately matches the temperature of the machining fluid. Machining with high machining accuracy can be started immediately upon restart, the time until the dimension stabilizes is also shorter than Δt ₂ (Δt ₁ ), productivity can be improved, and machining The dimensions are also equal to those at the initial startup, eliminating the need for dimensional correction. When the temperature of the machining fluid detected by the fluid temperature sensor deviates from the set temperature, the controller adjusts the temperature by cooling or heating the machining fluid stored in the tank so that the fluid temperature matches the set temperature. Therefore, the temperature of the machining fluid is always maintained at the set temperature, so that the workpiece can be machined at a constant temperature. Accordingly, the workpiece and the cutter are maintained at the set temperature without being affected by the ambient temperature change, and stable and highly accurate machining is possible.
[0028]
In addition, since the temperature setting is automatically performed at the initial startup and restarting of this thermostat, it is not necessary for the operator to measure the optimum temperature immediately before the start of machining as in the conventional case, and the optimum temperature is set. This eliminates the need to perform temperature management. In addition, dimensional accuracy of ± 1 μm is required in high precision machining, but according to the present invention, it is possible to sufficiently cope with such a case.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of a thermostatic device according to the present invention.
FIG. 2 is an explanatory diagram for explaining an internal structure of the thermostatic device shown in FIG. 1;
FIG. 3 is a flowchart showing a temperature setting process when a start switch is turned on in the constant temperature device according to the present invention.
FIG. 4 is a flowchart showing a preset temperature storage process when the start switch in the thermostatic device according to the present invention is off.
FIG. 5 is a graph showing a change with time of a processing liquid and room temperature and a change with time of a processing dimension in the thermostatic device shown in FIG. 1;
[Explanation of symbols]
1 thermostat 2 Tank 3 working fluid 4 liquid temperature sensor 5 temperature sensor 6 controller 7 heater 9 cooler 31 the temperature setting unit 32 Temperature controller 33 Temperature memory T _R ambient temperature (room temperature)
_TL Processing fluid temperature (liquid temperature)
T _S set temperature T _M Temperature stored in temperature memory

Claims (3)

A liquid temperature sensor for detecting the temperature of the machining fluid, an air temperature sensor for detecting the ambient temperature, and the ambient temperature detected by the air temperature sensor is set as a set temperature of the machining fluid and the set temperature set is a target value And a controller for controlling the temperature of the machining fluid. The controller stores the set temperature of the set machining fluid in a temperature memory, and at the same time the ambient temperature detected by the temperature sensor when the processing machine is restarted. Instead, a thermostatic device comprising a temperature read from the temperature memory can be set as a new set temperature. The constant temperature apparatus according to claim 1, wherein storing the set temperature of the machining fluid into the temperature memory is performed when a start switch of a machining machine is turned off. The working fluid is supplied from the tank to the processing unit of the tool provided in the processing machine and the workpiece set on the processing machine and processed by the tool, and then returned to the tank. The thermostat according to claim 1 or 2, wherein the thermostatic device is controlled by cooling or heating the machining fluid stored in the tank.

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