JPH0335060B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature control device for improving the machining accuracy of a machine tool such as a machining center lathe.

Prior art A well-known oil temperature control device for controlling the temperature of machinery in a lubricating oil unit is the
No. 16216 controls oil temperature according to atmospheric temperature,
There is a device that keeps the temperature gradient around the oil circulation device constant regardless of atmospheric temperature changes to eliminate distortion caused by thermal displacement around the device. There is a system that performs comparative control with respect to the atmospheric temperature and maintains the temperature difference between the circulating oil temperature and the atmospheric temperature at a constant value regardless of changes in the atmospheric temperature.

Problems to be Solved by the Invention However, machines have heat generation sources in multiple locations such as electric motors, drive systems, and main shaft bearings, each with a different temperature difference from the reference temperature. I couldn't control it enough.

Means for Solving the Problems Temperature sensors 61, 62, 63 for reference points are provided at positions distant from the heat generation site, and temperature sensors 20 for oil in the oil tank and temperature sensor 1 for the temperature controlled position are provided.
Reference point temperature sensors 61, 62,
63 and the respective temperature sensors 18, 19, 20 are provided, and adjustment means 64, 65, 66 for outputting a control signal by comparing the temperature difference between each temperature sensor 18, 19, 20 with a set value are provided, and the temperature of the oil tank 21 is adjusted by the adjustment means. It is provided with a cooling means 23 for controlling, a heating means, and selection means 42, 51 for adjusting the flow rate of the fluid.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. In a well-known machining center, bed 1
At the top, a column 2 is installed at the rear of the center, and at the front, a saddle is placed on the column 2 so that its position can be controlled back and forth, and a table is placed on the top surface of the saddle so that it can be positioned left and right.

A spindle head 3 is provided on vertical guide surfaces on both front sides of the column 2 so as to be vertically positionable, and a spindle 4 is rotatably supported by bearings in the vertical direction on the spindle head 3. An annular oil flow path 7 for cooling is formed on the outer periphery of the oil jacket 6 fitted with the oil jacket 6 between the spindle head 3 and an oil supply flow path 8 and an oil discharge flow path 9 in the spindle head 3. It is connected to the.

Further, an annular flow passage 1 is formed on the outer periphery of the oil jacket 11 fitted with the bearing 10 on the upper end side of the center of the main shaft 4.
2 is formed and connected to a supply channel and a discharge channel in the spindle head 3 (not shown). The main shaft 4 is the intermediate shaft 13
The rotation of the main motor 15 is transmitted through a gear group 14 . Since this main motor 15 becomes a heat generation source, it is connected to the spindle head 3 through a heat insulating material 16.
A cooling annular channel 17 is formed on the fixing surface on the spindle head side, and is connected to a supply channel and a discharge channel (not shown). A temperature sensor 18 for detecting the temperature of the bearing 5 is screwed onto the oil jacket 6, and a temperature sensor 19 for detecting the temperature of the mounting portion of the main motor 15 is screwed onto the mounting portion.
On the back of the machine, a lubricating oil tank 21 that also serves as cooling and a hydraulic oil tank 22 for hydraulic oil for tool changers, etc. are placed side by side, separated by an air layer, and a cooling device 23 is installed above them. There is. The oil in the lubricating oil tank 21 is supplied to the oil jackets 6, 11, the gear box of the spindle head 3, and the main motor 15 by means of two supply pumps P1 and P2.
Oil is supplied to the mounting part of the That is, on the supply pump P1 side, the oil in the tank is sucked up from the flow path 31,
Flow path 32, throttle valve 3 where the throttle amount is initially set
3 passages 34 to the passages 8, 7 and 12 of the spindle head 3.
At the same time, it is supplied to the gear meshing surface in the gear box through the flow path 53, and the discharge flow paths 9, 35,
From the flow paths 36 and 37, the drain oil pump P3 connects the flow path 38,
The cooled oil sent to the outer pipe of the double pipe cooler 39 in the hydraulic tank 22 is returned to the lubricating oil tank 21 through the flow path 40. Midway flow path 3 of this circulation system
A sequence valve 41 is installed between 1 and 32, and a flow path 32
A 2-port 2-position electromagnetic switching valve 42 is provided on the exhaust side, and a throttle valve 43 to which the throttle amount is initially set is provided on the discharge side. Then, when the solenoid SOL1 is activated and the switching valve 42 is in the I position, a part of the supplied oil is discharged and the amount of supplied oil to the bearing portion is reduced. On the supply pump P2 side, the oil in the lubricating oil tank 21 is sucked up from the flow path 45, and the main motor 15 is attached via the flow path 46, the throttle valve 47 where the throttle amount is first set, and the flow paths 48 and 17. The flow path 49,
37, is similarly cooled by a double-pipe cooler 39, and then returned to the lubricating oil tank 21. A sequence valve 50 is provided between the flow paths 45 and 46 in the middle of this circulation system, a 2-port 2-position electromagnetic switching valve 51 is provided in the flow path 46, and a throttle valve 5 whose throttle amount is initially set is placed on the discharge side.
2 is provided. And solenoid SOL2
When the switching valve 51 is in the I position, part of the supplied oil is discharged and the amount of supplied oil to the main motor mounting portion is reduced. Further, a temperature sensor 20 is provided in the lubricating oil tank 21 to measure the oil temperature. Further, the hydraulic tank 22 is provided with a supply pump P4 that supplies pressure oil to operate a tool changer and the like. The refrigeration system 23 has a built-in refrigerator 55, and refrigerant gas is sent from a cooling pipe 56 to the center pipe of the double-pipe cooler 39, cools the oil in the outer pipe, and then passes through the cooling pipe 57 and is blown by a condenser fan 58. It is air-cooled by a condenser 59 and refluxed to the refrigerator 55. and cooling pipe 56
and 57, there is a high/low pressure switch 60 for safety reasons.
is provided. A temperature sensor 61 for the reference point temperature for temperature control is located at the rear of the bed 1 of this machine at a position that is not affected by the heat of the main shaft 4, main motor 15, and drive system.
62 and 63 (one piece can be shared) are screwed together, and this temperature sensor 61 serves as a reference for the temperature sensor 20 for measuring the temperature of the lubricating oil tank 21. Compare the temperatures of both sensors in the follow-up differential temperature automatic temperature controller 64 (manufactured by Nihon Kuenall Co., Ltd. in this example), and if the set temperature difference (set to zero in this example) is no longer zero and the oil temperature side becomes higher, a signal is generated. is output to cause the refrigerator 55 to operate. The temperature sensor 62 serves as a reference for the temperature sensor 18 for the bearing 5 temperature detection side.In the same machine, the base point tracking differential temperature automatic temperature controller 65 compares the temperatures of both sensors, and if the temperature difference is greater than the set temperature difference, the bearing 5 is detected. When the side becomes higher, a signal is output and the switching valve 42 is switched to the position to stop the oil discharge and increase the amount of oil supplied.
The temperature sensor 63 serves as a reference for the temperature sensor 19 on the mounting part of the main motor 15.The temperature sensor 63 is used as a reference for the temperature sensor 19 on the mounting part of the main motor 15.The temperature of both sensors is compared using the base point tracking differential temperature automatic temperature controller 66 of the same machine. If the level becomes high, a signal is output to set the switching valve 51 to the position to stop draining the oil and increase the amount of oil supplied.

Function Next, the function will be explained with reference to FIGS. 4, 5, and 6 of the control circuit.

The machining center initially had solenoid switching valves 42 and 51.
Solenoids SOL1 and SOL2 are activated and in their respective positions send some of the supplied oil to the side passage, supplying a small amount of oil. If machining continues in this state, the position of the bed 1 away from heat generation sources such as the electric motor 15, oil tanks 21 and 22, cutting parts, and drive system will generally be affected by some heat conduction and atmospheric temperature. Although there are slight temperature changes, it maintains a relatively stable temperature. Therefore, temperature sensors 60, 61, 6
The temperature detected by sensor 2 can be used as a reference point, whereas the temperature detected by temperature sensor 1 of bearing 5 of main shaft 4
8. The temperatures detected by the temperature sensor 19 of the main motor 15 attachment part and the temperature sensor 20 of the lubricating oil tank 21 gradually rise during the operating state, and the temperature equilibrium state collapses. Therefore, the temperature detected by the temperature sensor 20 is compared by the automatic temperature controller 64, and when the temperature detected by the temperature sensor 20 becomes high, the switch MS3 of the refrigerator 55 is turned on and the refrigerant gas is circulated to the double pipe type cooler 39. The oil returned from the flow path 38 is cooled, and the oil in the hydraulic tank 22 is also cooled. This cooled lubricating oil tank 2
The oil in 1 is sent out from the flow path 31 by the dual supply pump P1, passes through the flow path 32 and the throttle valve 33, cools the oil jackets 6 and 11 in the flow paths 7 and 12, and is sent to the gear group from the flow path 53. The temperature sensor 18 is lubricated to suppress the temperature rise of the bearing part, but as the operating time increases, the balance between cooling and generated heat is lost, causing the temperature sensor 18 to lubricate.
When the detected temperature becomes higher than the detected temperature of the standard temperature sensor 62 and the temperature difference is no longer the set temperature difference of zero, the solenoid SOL1 of the electromagnetic switching valve 42 is demagnetized and switched to the position by the action of the automatic temperature regulator 65. The bearings 5 and 10 are sufficiently cooled by the increased amount of supplied oil, which is partially discharged.

When the temperature detected by the temperature sensor 18 falls, the automatic temperature regulator 64 is activated again, the electromagnetic switching valve 42 is switched, and the amount of cooling oil sent to the bearing portion is reduced. By repeating this process, the temperature inside the bearings 5 and 10 is maintained in a stable state in line with the reference point temperature. In addition, although the heat generated by the operation of the main motor 15 is prevented from being transferred by the insulating material 16 at the mounting part, it cannot be completely shut off, and the temperature detected by the temperature sensor 19 at the mounting part is the detection temperature of the reference temperature sensor 63. When the temperature rises further and the temperature difference is no longer the set temperature difference of zero, the automatic temperature controller 66 operates to close the solenoid switching valve 5.
The solenoid SOL2 of No. 1 is demagnetized and switched to the demagnetized position, part of the supplied oil is stopped from being discharged, and the increased amount of oil is sent to the flow path 17 to increase the cooling effect of the mounting part and lower the temperature. When the temperature detected by the temperature sensor 19 falls below the temperature detected by the reference temperature sensor 63, the automatic temperature regulator 66 switches the electromagnetic switching valve 51 again to reduce the supply of oil. By repeating this process, the temperature of the attachment part is kept stable. In addition, if the bearing or main motor mounting part becomes too cool, either stop the operation of the refrigerator separately or use intermittent operation to temporarily stop cooling the oil tank. Alternatively, the cooling capacity is reduced to cope with the temperature rise due to oil circulation. Further, the refrigerator or the pipe line can be controlled and operated so as to adjust the flow rate of the refrigerant gas in response to rises and falls in oil temperature. Furthermore, a temperature sensor is provided in the drive system section as necessary, and each section is individually controlled. Furthermore, when the main shaft is stopped, only the electric motor section is cooled at any time. In the above explanation, we mainly talked about cooling the oil, but since the main purpose is to control the temperature so that it all matches the temperature at the reference point, it is necessary to install a heater and heat the oil so that it matches the temperature at the reference point. Of course, this can also be done.

Effects As detailed above, the present invention is different from the one that controls the temperature of an oil circulation device etc. with respect to the atmospheric temperature, and in addition to the oil in the oil tank, the present invention also controls the temperature of the heat generating part of the machine to the temperature of the reference point. The flow rate of the heated or cooled oil is adjusted to maintain a stable state through careful control, which prevents deformation of each part due to heat and enables stable, high-precision machining. .

[Brief explanation of the drawing]

FIG. 1 is a control circuit diagram of the present invention, FIG. 2 is a diagram showing the mounting position of a reference temperature sensor, and FIG. 3 is a partial cross-sectional view of the spindle head. 4, 5 and 6 are control circuit diagrams. DESCRIPTION OF SYMBOLS 1... Bed, 4... Main shaft, 6, 11... Oil jacket, 5, 10... Bearing, 7, 12, 17... Annular flow path, 15... Main motor, 21... Lubricating oil tank, 2
2... Hydraulic tank, P1, P2, P4... Supply pump, P3... Drain pump, 18, 19, 20... Temperature sensor, 42, 51... Solenoid switching valve, 61, 62,
63...Temperature sensor for reference point, 64, 65, 66
...Base point tracking differential temperature automatic temperature controller.

Claims (1)

[Scope of Claims] 1. A reference point temperature sensor is provided in the machine body at a location far from heat generation sources such as the electric motor, main shaft, drive system, etc. and where there is little temperature change, or in the atmosphere, and the temperature of the oil in the oil tank is detected. A first temperature sensor is provided, and one or more second temperature sensors are provided at one or more temperature-controlled positions of the machine to detect the temperature at that position, and the temperature of the reference point temperature sensor and the first temperature sensor are A first adjustment means is provided for detecting a temperature difference between the reference point temperature sensor and the second temperature sensor and outputting a control signal. A second adjustment means is provided corresponding to the second temperature sensor, a temperature control means for the oil in the tank whose operation is controlled by the first adjustment means is provided, and the temperature of the oil in the tank is controlled by the second adjustment means. A means for adjusting the flow rate of lubricating/heating/cooling oil supplied to the control position is provided corresponding to the temperature controlled position, and the temperature of the oil tank and the temperature controlled position is independently controlled to follow the reference point temperature. A temperature control device characterized by: 2. The temperature control device according to claim 1, wherein the temperature control means for the oil in the tank is a cooling means. 3. The temperature control device according to claim 1 or 2, wherein the temperature control means for the oil in the tank is a heating means.