JPH0725014B2 - Machine tool cooling system - Google Patents

Description

The present invention relates to a cooling device for machine tools. More specifically, the present invention relates to a cooling device for a machine tool, in which a unit type cooling device is incorporated in a heat generating body portion that constitutes a machine tool, and only the heat generating portion is cooled.

[Prior Art] A machine tool includes a heat source in each part of the machine body. For example,
There are many such things as rolling friction heat of the bearing of the main shaft, heat generated from the cutting tool, and heat generated from the hydraulic drive unit. These heat sources are conducted to each part of the machine body and deform the machine body. The deformation of the machine body affects the processing accuracy. For example, in a spindle head of a machine tool, heat is generated due to rolling friction or sliding friction of a bearing portion that holds and rotates a tool or a workpiece. The generated heat is the main factor that thermally deforms the spindle head.
This spindle head is cooled by passing cooling oil, which is normally cooled by a cooling device, through the spindle head.

The cooling device is controlled to cool the cooling oil so that the cooling oil always has a set temperature. The cooling device is installed in a place different from the machine tool body, and introduces cooling oil by piping to cool it. This set temperature is often set to be the same as room temperature. This is because when the set temperature is lower than room temperature, dew condensation occurs on the spindle head, so that the cooling oil is not normally set lower than room temperature. In particular, in the case of a machine tool in which the rotation speed of the spindle changes drastically, the temperature of the spindle head rises unless the heat fluctuation is dealt with quickly.

Therefore, the displacement of the spindle head becomes large due to the heat generated in the spindle head, and as a result, the machining accuracy is reduced. Further, in the above-mentioned conventional cooling system, the so-called steady deviation amount in which the temperature fluctuates up and down is large due to the dead time of the temperature correction operation, the operation clearance, and the like. On the other hand, the units constituting the machine tool are divided into units such as a bed, a spindle head, a tool rest, and a driving device. The idea of constructing a machine tool by assembling this unit as much as possible has long been known.

[Problems to be Solved by the Invention] A cooling device is installed at a position different from that of a machine tool body, and a refrigerant is guided by a pipeline. This method lengthens the pipeline,
Inevitably, heat loss and friction loss of the refrigerant increase. Further, when controlling the refrigerant to a set temperature (usually room temperature), the steady deviation becomes large. If the sensor is arranged in consideration of the above loss to reduce the steady deviation, the control valve, the control circuit, etc. become complicated.

The above-mentioned unit constituting the machine tool (used synonymously with element here) does not consider the heat problem. Therefore, the heat generated in each unit is conducted not only to the unit but also to the other unit to deform the other unit. The present invention has been made under the technical background as described above, and achieves the following objects.

An object of the present invention is to provide a cooling device for a machine tool that is integrally incorporated in a machine body that constitutes the machine tool.

Another object of the present invention is to provide a cooling device for a machine tool, which cools the heat generated by the elements constituting the machine tool to the other parts of the machine body without cooling the heat generated by the heat generation source.

[Means for Solving the Problems] The following means are adopted to solve the problems.

In a machine tool that performs machining, a. A spindle head equipped with a built-in motor in which a rotor is installed in a spindle that is rotatably installed in the machine tool and a stator is installed in a fixed body; and b. The stator of this spindle head is cooled. A unit cooling device that is integrally incorporated in the spindle head and that has a built-in cold heat generating unit to generate the refrigerant gas generated in the refrigeration cycle; and c. Circulate the refrigerant gas generated by the unit cooling device. And a heat exchanging means formed on the outer periphery of the stator for exchanging the cooling heat and the heat generated in the spindle head.

It is still effective to interpose a vibration damping material between the unit cooling device and the spindle head.

[Operation] Heat is generated in the machine body elements that make up the machine tool. A cooling device is integrated into the heat generation source. Cooling is performed within the fuselage element with a cooling device that incorporates the heat of the heat source.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment applied to cooling the spindle head 3 of the NC lathe 1. The NC lathe 1 has a bed 2 which is a main body frame. It comprises a spindle head 3 provided at one end on the bed 2 and a tailstock 4 provided so as to face the spindle head 3. Further, it comprises a carriage 5 moving on the bed 2, a turret tool rest 6 on the carriage 5, and the like. Since these units are conventionally known, their description is omitted here. A cooling device 10 is integrally incorporated and provided on the spindle head 3.

Outside air a is taken into the cooling device 10 from the entire surface of the NC lathe 10, the spindle head 10 is cooled, and then exhaust gas containing exhaust heat is discharged to the outside of the cooling device 10. FIG. 2 is a sectional view taken along the line II-II in FIG. A spindle 11 is rotatably supported in the spindle head 3 by bearings 12, 12. On the outer circumference of the spindle 11,
The rotor 13 of the induction motor is fixed. The rotor 13 is formed by stacking silicon steel plates. On the other hand, a heat exchanger 15 is fixed to the spindle head 3. The heat exchanger 15 exchanges heat with the refrigerant gas in order to exhaust heat generated by the spindle motor as described later.

The heat exchanger 15 has a cylindrical shape, and a spiral groove 16 is cut on the outer circumference. An O-ring 17 is interposed between the spindle head 3 and the heat exchanger 15 so that the refrigerant gas does not leak out. In addition to the O-ring 17, other known sealing means such as a gasket may be used as long as it maintains the airtightness between the spindle head 3 and the heat exchanger 15. A stator 18 is fixed to the inner peripheral surface of the heat exchanger 15. An induction coil 19 is wound around the stator 18. The outer periphery of the stator 18 and the outer periphery of the heat exchanger 15 are airtightly inserted so that heat can be easily conducted. After all, the rotor 13 and the stator 18 of the main shaft 11 constitute a motor. On the other hand, the spindle head 3
The cooling device 10 is integrally mounted on the top. Cooling system
The outer periphery of the frame 10 (not shown) is covered with a plate member 21. The sheet metal material 21 is a vibration damping type sheet metal material coated with a synthetic resin or the like. This is for damping the vibration of the motor provided inside so as not to transmit it to the spindle head.

The inner peripheral surface of the sheet metal material 21 is coated with a heat insulating material 22. The heat insulating material 22 prevents heat generated in the cooling device 20 from being conducted to the airframe. Furthermore, the cooling device 10
A vibration damping material 23 is interposed between the spindle head 3 and the spindle head 3. The vibration damping material 23 cools the vibration of the spindle head 3 by a cooling device.
On the contrary, the vibration of the cooling device 10 is not transmitted to the spindle head 3 in order not to transmit the vibration to the spindle 10.

The compressor 30 compresses the refrigerant gas into a high pressure and high temperature state. The compressor 30 is driven by a motor 31.
The compressor 30 may be of any known type,
A device that can be downsized is desirable. The refrigerant gas exiting the compressor 30 passes through the pipe 32 and is radiated by the condenser 33. This heat dissipation is
This is performed by rotationally driving the fan 34 driven by the motor 35. The heat-dissipated and liquefied refrigerant gas passes through the pipe 36 and enters the liquid receiver 37. The liquid in the liquid receiver 37 is squeezed and expanded by the expansion valve 38 to be in a low-pressure low-temperature gas-liquid mixed state.

In this state, it enters the inlet 39 of the heat exchanger 15. On the other hand, Joule heat is generated in the induction coil 19, the stator 18, and the rotor 13. Heat is also generated in the bearings 12, 12. Since the heat exchanger 15 is a so-called evaporator when it is called a refrigerator, the heat exchanger 15 takes out heat generated from the surroundings and vaporizes it, and then follows the spiral groove 16 to exit to the outlet 40 and return to the compressor 30.

[Other Embodiments] In the above-described embodiments, the exhaust heat is discharged in the direction perpendicular to the main shaft, but it may be exhausted to the rear portion of the main shaft in parallel with the main shaft 11.
The cooling device described above may be another known cooling device such as a multi-stage compression type, electronic refrigeration, which was a single-stage compression cooling device. Moreover, the above-mentioned heat insulating material was only a heat insulating material. However, aluminum foil or the like may be attached to prevent radiation. Further, the cooling device of the above-mentioned embodiment is provided in the spindle head and mainly cools the heat generated from the spindle motor.

However, the heat generation source of the machine tool is not limited to this location, but is also generated from the bearing, sliding parts of the feed screw and nut, sliding surfaces of the carriage and bed, machine elements in contact with cutting oil, etc. To do. Therefore, similarly to the above-described embodiment, other parts constituting the machine tool can be cooled by the same technical idea as described above. In addition, the machine body element described above does not mean a machine body of a modular machine tool.

[Effects of the Invention] As described in detail above, since the present invention is only attached to the heat source of the machine tool, the cooling device becomes compact and the floor area is also reduced. The conduit for the refrigerant gas in the cooling device can be very short. Therefore, the cooling efficiency is improved and the steady-state deviation is small.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of a cooling device for a unit of a machine tool, and FIG. 2 is a sectional view taken along line II-II of FIG. 1 ... NC lathe, 2 ... bed, 3 ... spindle head, 10 ...
…Cooling system

Claims (2)

[Claims] 1. A machine tool for machining, comprising: a. A spindle head having a built-in motor in which a rotor is incorporated in a spindle rotatably mounted on the machine tool and a stator is incorporated in a fixed body; and b. A unit cooling device that is integrally incorporated in the spindle head to cool the stator, and has a built-in cold heat generating means to generate the refrigerant gas generated in the refrigeration cycle; and c. A cooling device for a machine tool, comprising: heat exchange means formed on the outer periphery of the stator to circulate the coolant gas to exchange cooling heat with heat generated in the spindle head. 2. The cooling device for a machine tool according to claim 1, comprising the unit cooling device and a vibration damping material interposed between the spindle head.