JP4083283B2 - Constant temperature apparatus and temperature control method for the constant temperature apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thermostat applied to a lathe that is a high-precision machine and a temperature control method for the thermostat.
[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. Therefore, the machining factory has almost no air-conditioning equipment. is there. In general factories without air-conditioning facilities, the room temperature changes drastically, and the room temperature changes from morning to night in the day, and also changes due to changes in the seasons, and the temperature difference is extremely large. Since the processing machine itself as well as the workpiece causes thermal expansion and contraction due to this temperature difference, this temperature difference cannot be ignored when high precision machining is required for the workpiece.
[0003]
Therefore, in order to achieve high-precision machining, a constant temperature device is conventionally provided to maintain the temperature of the cutting fluid at a constant temperature, and the cutting fluid adjusted to a constant temperature is supplied to workpieces, tools, etc. This prevents the temperature of the workpiece being processed from changing even if the ambient temperature changes. Conventionally, there are various types of constant temperature devices of this type. For example, the constant temperature device disclosed in Japanese Patent Publication No. 61-57145 is added and averaged according to the average time of room temperature in the working machine operating time zone. The temperature of the cutting fluid and the temperature of the lubricating oil are set, and the temperature of the cutting fluid and the lubricating oil is controlled so as to maintain the set temperature.
[0004]
As another conventional thermostatic device, one shown in FIG. 5 is known. 5 is a tank 2 that stores the cutting fluid 3 to be supplied to the lathe 24, a temperature sensor 25 that detects the temperature of the cutting fluid 3 in the tank 2, and a temperature for setting the cutting fluid. A setting device 26 and a temperature control device (not shown) for controlling the temperature of the cutting fluid 3 in the tank 2 so as to become the set temperature are provided. The constant temperature device 23 is called a manual setting method, and before starting the lathe 24, the set temperature is set by the operator measuring the ambient temperature and inputting the optimum temperature to the setting device 26. In the thermostatic device 23, the set temperature is determined and inputted to the controller in consideration of the temperature read from the thermometer or the like by the operator, so that the set temperature does not necessarily coincide with the room temperature at the start of processing as shown in FIG. The liquid temperature of the cutting fluid 3 is controlled so as to coincide with the set temperature even when the room temperature changes, and is maintained at a constant temperature.
[0005]
Further, as another conventional thermostatic device, one as shown in FIG. 7 is known. The constant temperature device 27 in FIG. 7 includes a tank 2 for storing the cutting fluid to be supplied to the lathe 24, a liquid temperature sensor 28 for detecting the temperature of the cutting fluid 3 in the tank 2, a reference temperature sensor 29 for detecting the ambient temperature, and a reference. An automatic setting device 30 for setting the temperature detected by the temperature sensor 29 as a set temperature, and a temperature control device (not shown) for controlling the temperature of the cutting fluid 3 in the tank 2 to match the set temperature are provided. ing. The thermostatic device 27 is called an automatic tracking method, and the ambient temperature measured by the reference temperature sensor 29 is automatically set as a reference temperature automatically in real time. In the thermostatic device 27, as shown in FIG. 8, the temperature of the cutting fluid 3 is controlled so as to coincide with the reference temperature, but the set temperature changes from moment to moment due to changes in the ambient temperature. Will also change as the ambient temperature changes.
[0006]
[Problems to be solved by the invention]
However, in the thermostatic device disclosed in Japanese Patent Publication No. 61-57145, the average room temperature in the operating time zone of the processing machine is detected every day, stored for a certain period, and the average is obtained for the next day by obtaining the average. Thus, the set temperature of the cutting fluid and the lubricating oil is set when the processing machine is started, and is maintained at a constant temperature throughout the day. As described above, in the thermostatic apparatus, the predicted value is set as the set temperature, and therefore, the set temperature does not coincide with the room temperature when the processing machine is started. Therefore, both the cutting fluid temperature and the lubricating oil temperature immediately before the start-up of the processing machine are normally at room temperature, so it takes a considerable time for each temperature to reach the set temperature. There is a problem that machining cannot be started immediately on the workpiece upon start-up, and waiting or idling must be performed for a while.
[0007]
On the other hand, the thermostatic device shown in FIG. 5 controls the temperature so that the temperature of the cutting fluid becomes the set temperature. Therefore, if the measured room temperature is set as the set temperature, the standby time hardly occurs. . However, it is always necessary to set the temperature with an operator, and it is necessary to perform daily operations such as measuring the optimum temperature to be set immediately before starting the processing, that is, immediately before starting the processing machine. Prone. In addition, high-precision machining of workpieces requires machining dimensional accuracy of ± 1 μm. In such cases, strict temperature control of ± 0.1 ° C level is required, and the operator measures with a thermometer or the like. If the set temperature is determined in consideration of the measured temperature and input to the controller, sufficient temperature control as required for high-density machining of the workpiece cannot be performed.
[0008]
Further, in the thermostatic device shown in FIG. 7, the ambient temperature is detected by the reference temperature sensor, and the detected temperature is automatically set as the set temperature. Therefore, if the ambient temperature changes as shown in FIG. Accordingly, the set temperature also changes accordingly. Therefore, each time the ambient temperature changes, the set value of the thermostatic device changes. As a result, the machining accuracy also changes, and a certain accuracy cannot be maintained. That is, there is a problem that the machining accuracy varies depending on the detection value of the reference temperature sensor.
[0009]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and a temperature at the start of machining of a lathe that is a machining machine is automatically detected by a temperature sensor, and the detected temperature is set as a set temperature of a constant temperature device. Fill in, by the control for maintaining the setting temperature during processing, eliminating most of the waiting time at the machining start of the lathe, eliminating the temperature fluctuations during processing of the lathe itself and the workpiece, lathe itself due to temperature variations Another object of the present invention is to provide a thermostat and a temperature control method for the thermostat capable of eliminating deformation of the workpiece and ensuring high-precision machining of the workpiece.
[0010]
The present invention relates to a liquid temperature sensor for detecting the temperature of a cutting fluid stored in a tank, an air temperature sensor installed at an arbitrary place in a lathe which is a processing machine for detecting an ambient temperature, and activation of the lathe An automatic temperature setter that automatically sets the temperature detected by the temperature sensor as a set temperature, and a temperature control device that adjusts the temperature of the cutting fluid so that the temperature detected by the liquid temperature sensor becomes the set temperature It is related with the thermostat characterized by comprising .
[0011]
When the lathe as a processing machine is started, for example, when a start switch is turned on, the temperature sensor detects the ambient temperature, that is, the room temperature, and the automatic setting device automatically sets the detected room temperature as the set temperature. Therefore, it is not necessary to wait until the temperature of the cutting fluid matches the set temperature because the temperature of the cutting fluid usually matches the room temperature when the lathe is started. When the temperature of the cutting fluid detected by the fluid temperature sensor deviates from the set temperature, the temperature controller cools or heats the cutting fluid stored in the tank so that the temperature of the cutting fluid matches the set temperature. Adjust the temperature with. Cutting fluid which is maintained at a set temperature is fed to the lathe, a workpiece during machining set in the lathe tool and the heating unit in the lathe cooling. Thus, lathe, workpiece or tool without being affected by changes in ambient temperature, because it is maintained at a constant temperature, it becomes possible to high-precision processing.
[0012]
Further, the present invention is to maintain a cutting fluid supplied to the lathe at a set temperature in order to cool the workpiece, the cutting tool, and the heat generating part in the lathe set on the lathe which is a processing machine. In the temperature control method of the thermostatic device,
Automatically detect the ambient temperature at the time of processing start of the lathe temperature sensor installed anywhere in the lathe, sets the detection value as the set temperature, the temperature of the cutting fluid said set temperature The present invention relates to a temperature control method for a thermostatic device, wherein the temperature is controlled so as to be maintained.
[0013]
According to the temperature control method of the thermostat, the ambient temperature at the start of lathe machining is automatically set as the set temperature. When the lathe is started up, the temperature of the lathe itself, the workpiece, the cutting fluid, etc. usually matches the ambient temperature, so there is no need to wait until the temperature of the cutting fluid matches the set temperature. Then, the cutting fluid set temperature is fed to the lathe, to maintain the workpiece and tool in the machining set in the lathe to their initial temperature. Even if the temperature of the cutting fluid changes from the set temperature, the temperature of the cutting fluid stored in the tank is adjusted so that the set temperature is reached. Then, the cutting fluid which is adjusted to the set temperature is supplied to the lathe, since the workpiece and tool is maintained at a constant temperature i.e. the set temperature without being affected by the ambient temperature change, lathe machining precision It becomes possible.
[0014]
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.
[0015]
As shown in FIGS. 1 and 2, the thermostatic device 1 includes a liquid temperature sensor 4 for detecting the temperature of the cutting fluid 3 stored in the tank 2, an air temperature sensor 5 for detecting the room temperature that is the ambient temperature, and machining. The automatic temperature setting device 31 as an automatic setting device that automatically sets the temperature detected by the air temperature sensor 5 when the lathe as a machine is started up as the set temperature, and the temperature detected by the liquid temperature sensor 4 become the set temperature. Is provided with a temperature control device 32 for adjusting the temperature of the cutting fluid 3. Further, the automatic temperature setting device 31 and the temperature control device 32 are built in the temperature controller 6. In addition, the thermostatic device 1 includes a U-shaped heater 7 for heating the cutting fluid 3 and a refrigeration device 8 for cooling the cutting fluid 3. Most of the refrigeration apparatus 8 excluding the cooler 9 and the temperature controller 6 are housed 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 cutting fluid 3 in a state where these protruding devices 4, 7, 9, 11 are immersed in the cutting fluid 3. The air temperature sensor 5 can be installed at an arbitrary position around the lathe so that the optimum room temperature can be detected. That is, the air temperature sensor 5 can be installed at an arbitrary place in the lathe in order to detect the temperature of a desired region.
[0016]
As shown in FIG. 2, the refrigeration apparatus 10 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 cutting fluid 3, heat is taken from the cutting fluid 3 to cool the cutting fluid 3.
[0018]
The cooler 9 is spirally wound and formed in a cylindrical shape, and a stirring disk 11 is provided in the cooler 9. The stirring disk 11 is driven by a stirring motor 21 to stir the cutting fluid 3 to make the temperature distribution in the tank 2 uniform.
[0019]
The heater 7 heats the cutting fluid 3 and is provided with an airing prevention switch 20 in order to prevent airing. When the cutting fluid 3 in the tank 2 is insufficient, the emptying 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.
[0020]
The liquid temperature sensor 4 immersed in the cutting fluid 3 in the tank 2 and the air temperature sensor 5 for detecting the room temperature are connected to the temperature controller 6, and the detected temperature detected by each sensor 4, 5 is the temperature. Input to the controller 6. The room temperature detected by the temperature sensor 5 is configured to be input to the temperature controller 6 when a start switch (not shown) of a lathe (not shown) is turned on, and the room temperature is input to the temperature controller 6. Then, the automatic temperature setter 31 provided in the temperature controller 6 automatically sets the room temperature at that time as the set temperature.
[0021]
The temperature controller 32 of the temperature controller 6 controls the heater 7 or the refrigeration apparatus 8 to adjust the temperature so that the temperature of the cutting fluid 3 detected by the fluid temperature sensor 4 matches the set temperature. As shown in FIG. 3, the temperature of the cutting fluid 3 is always controlled to be substantially equal to the set temperature even if the room temperature changes. Then, the cutting fluid 3 which is temperature regulated, workpiece set on a lathe, and is supplied to the lathe in order to cool the heat generating portion of the tool and the working machine.
[0022]
The workpiece is required to be machined to an accurate dimension at a reference temperature. For example, if the reference temperature is 20 ° C, the workpiece must be finished to the correct dimensions at 20 ° C. Moreover, it is desirable that the measuring instrument and the lathe for measuring the dimension of the workpiece after machining are installed in the same room, but there are cases where the machine is not necessarily installed in the same room. For example, if the temperature in the room where the lathe is installed is 22 ° C. and the temperature in the measurement room is 20 ° C., the absolute value of the machining dimension will be shifted by 2 degrees. Therefore, the thermostat 1 is provided with a temperature difference setting function (not shown) between the lathe and the measurement chamber, and the temperature set value can be arbitrarily shifted with respect to the actual room temperature. It is possible to correct a processing dimension change due to room temperature difference. The differential temperature setting function can also be used as a means for supplying oil lower than room temperature in advance as cooling oil in order to preliminarily assume the heat generation of the lathe and completely absorb the heat.
[0023]
In the thermostatic device 1, the room temperature when the lathe is started is set as the set temperature. For example, if the room temperature is 22 ° C, the workpiece is finished at 22 ° C. Therefore, the thermostat 1 is provided with an input means (not shown) such as a numeric keypad for inputting a reference temperature and an input means (not shown) for inputting a material or a linear expansion coefficient on the operation panel 22. In addition, a calculation means (not shown) for calculating a correction value based on the difference between the set temperature and the reference temperature is provided. When the material is input, the linear expansion coefficient stored in the storage unit (not shown) is called. When the linear expansion coefficient is input, the linear expansion coefficient is used to set the set temperature and Since it is configured to calculate the dimension at the set temperature from the difference from the reference temperature, high-precision machining at the reference temperature becomes possible.
[0024]
Next, the operation of the thermostatic device 1 according to the present invention will be described. First, when starting machining, the operator turns on the start switch. When the start switch is turned on, the temperature sensor 5 automatically detects the current room temperature and a signal is input to the temperature controller 6. When the detected room temperature is input to the temperature controller 6, an automatic temperature setter 31 provided in the temperature controller 6 automatically sets the room temperature at that time as the set temperature. Since the temperature of the cutting fluid 3 usually coincides with the room temperature at the start-up, the set temperature is equal to the fluid temperature as shown in FIG. Therefore, the lathe can be operated immediately without requiring a waiting time after the lathe is started.
[0025]
When machining on the workpiece is started by the lathe , the cutting fluid 3 in the tank 2 is supplied to the workpiece, the tool, and the heat generating part in the lathe , and the workpiece is machined while cooling them. The liquid temperature of the cutting fluid 3 in the tank 2 changes due to machining or changes in room temperature, causing a deviation from the set temperature. The liquid temperature sensor 4 always detects the liquid temperature of the cutting fluid 3. Therefore, the temperature controller 32 of the temperature controller 6 adjusts the temperature so that the detected liquid temperature matches the set temperature. That is, when the liquid temperature is lower than the set temperature, the heater 7 is energized to heat the cutting liquid 3, and when the liquid temperature is higher than the set temperature, the refrigeration apparatus 8 is operated to cool the cutting liquid 3. . Further, in order to accurately detect the temperature of the cutting fluid 3, the stirring disk 11 is constantly driven by a stirring motor 21 so that the temperature distribution of the cutting fluid 3 in the tank 2 is uniform. In this way, the temperature is adjusted by feedback control so that the temperature of the cutting fluid 3 matches or maintains the set temperature. Therefore, as shown in FIG. 3, even if the room temperature changes, the temperature of the cutting fluid 3 is always maintained at the set temperature. Therefore, the workpiece and the tool are not affected by the change in the room temperature, and the set temperature and The same temperature is maintained and the workpiece is machined with high precision.
[0026]
Next, with reference to FIG. 4, the experimental result regarding the processing accuracy of the thermostat 1 will be described. In FIG. 4, the horizontal axis represents the machining time (minutes), and the vertical axis represents the machining dimensions (μm). FIG. 4 shows a comparison of differences in processing accuracy due to differences in set temperature when the room temperature is 21.5 ° C. (A) is the case where the set temperature is set to 21.5 ° C., which is the same as the room temperature, (B) is the case where the set temperature is set to 21.0 ° C. which is slightly lower than the room temperature, and (C) is This is a comparison with the case where the set temperature is set to 22.0 ° C., which is slightly higher than room temperature.
[0027]
It can be seen that when the temperature is set to 21.5 ° C., which is the same as the room temperature, the machining dimensions hardly change even when the machining time elapses, and high accuracy is maintained. On the other hand, when 21.0 ° C., which is slightly lower than room temperature, is set, an error occurs in the processing dimension as the processing time elapses, and an error of just over +1 μm is generated. Conversely, when the set temperature is set to 22.0 ° C., which is a little higher than room temperature, it can be seen that an error of slightly over −1 μm occurs. Just setting a temperature that deviates by about ± 0.5 ° C from room temperature results in a processing error such as (B) or (C). As described above, when the set temperature is set to the same temperature as the room temperature, high-precision machining can be maintained. However, if the set temperature slightly deviates from the room temperature, an error of about 1 μm occurs. I understand that. Therefore, when high-precision machining that requires an error in machining dimensions of about 1 μm is required, the temperature of the cutting fluid is set by setting the temperature to the same temperature as the room temperature as in the thermostatic device 1 of the present invention. It can be understood from this experimental result that maintaining the temperature at the set temperature is extremely important for high-precision machining of the workpiece.
[0028]
【The invention's effect】
Since the thermostat and the temperature control method thereof according to the present invention have the configuration described above, the following effects are obtained. That is, according to the present invention, since the automatically set as the set temperature ambient temperature detected at the start of turning, since the startup of the lathe temperature of the cutting fluid matches the set temperature, the activation of the lathe at the same time Machining can be started immediately, and it is not necessary to wait until the temperature of the cutting fluid reaches the set temperature as in the prior art, and productivity can be improved. In addition, 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 fluid temperature matches the set temperature. Since the adjustment is performed, the temperature of the cutting fluid is always maintained at the set temperature, so that the workpiece can be machined at a constant temperature. Therefore, lathe, workpiece or tool without being affected by changes in ambient temperature, is maintained at the set temperature, it is possible to process a stable high accuracy.
[0029]
In addition, since the temperature setting is performed automatically in 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 it is not necessary to set the optimum temperature, making temperature management easier. You can do it. 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 the internal structure of the thermostatic device shown in FIG. 1;
FIG. 3 is a graph showing the relationship between the cutting fluid and the temperature change at room temperature in the thermostatic device shown in FIG. 1;
FIG. 4 is a graph showing experimental results related to machining accuracy.
FIG. 5 is a schematic view showing a conventional thermostatic device.
6 is a graph showing the relationship between the cutting fluid and the temperature change at room temperature in the thermostatic device shown in FIG.
FIG. 7 is a schematic view showing another conventional thermostatic device.
8 is a graph showing the relationship between the cutting fluid and the temperature change at room temperature in the thermostatic device shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Constant temperature apparatus 2 Tank 3 Cutting fluid 4 Liquid temperature sensor 5 Air temperature sensor 31 Automatic temperature setting device 32 Temperature control apparatus

Claims (2)

A liquid temperature sensor for detecting the temperature of the cutting fluid stored in the tank, an air temperature sensor installed at an arbitrary place in the lathe as a processing machine for detecting the ambient temperature, and the air temperature sensor at the time of starting the lathe in automatic temperature setting device automatically set the detected temperature as a set temperature, and is composed of a temperature control device temperature detected by the liquid temperature sensor to adjust the temperature of the cutting fluid so that the set temperature A thermostatic device characterized in that Workpiece during machining lathe is set in a processing machine, the temperature control method of a thermostatic apparatus for maintaining the blade and cutting fluid supplied to the lathe in order to cool the heat generating portion in the lathe at a set temperature In
Automatically detect the ambient temperature at the time of processing start of the lathe temperature sensor installed anywhere in the lathe, sets the detection value as the set temperature, the temperature of the cutting fluid said set temperature A temperature control method for a thermostatic device, wherein the temperature is controlled so as to be maintained.

Images