JPS63288643A - Super precision machine tool - Google Patents

Abstract

PURPOSE:To eliminate almost completely the effect of heat produced by a motor by covering a motor with an outer shroud of a heat insulation material allowing an exhaust space communicating to outside between the motor periphery and a case, and arranging a motor shaft with a gap with respect to a supporting portion and the heat insulator. CONSTITUTION:Air in an air pocket 20 is drawn out to an exhaust space 18 as jet air from a nozzle 23 passing through a jet hole 22 produces venturi effect. By the depression at this time, air around a motor shaft 25 is sucked up through a communication clearance 24 so that the air is positively moved and exhausted outside. Air in the exhaust space 18 is released rapidly to the outside by the pressure of the jet air.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an ultra-precision machine tool that maintains the entire machine tool at a constant and uniform temperature.

In conventional machine tools, ultra-precision machine tools that perform turning on the order of 1/10 μm to 1/100 μm are in charge of the machine] J
Fluctuations and non-uniformity in i greatly affect machining accuracy, so the entire machine tool is housed in a case to maintain a constant internal temperature, and if necessary, the entire machine is given an oil shower with constant temperature oil. Comprehensive measures are also being taken to keep the temperature of the entire machine constant and uniform, such as replacing machines' sliding bearings, rolling bearings, and other items that generate a large amount of heat with air bearings that use temperature-controlled air.

One of the most important aspects of such ultra-precision machine tools is the treatment of heat generated by the motor used for the driving force for feeding and rotation.

It is probably possible to develop a special motor with low heat generation for ultra-precision machine tools, but at present, general-purpose motors with relatively high heat generation are used due to cost, and it is necessary to remove the heat generated by the motor. When installing the motor, use a heat insulating material such as Plus Deck on the seat, or install it by circulating air or liquid inside the seat, or by directly contacting the connection between the motor shaft and the shaft on the machine body side. In addition, the outer surface of the motor is covered with a jacket made of a heat insulating material with a gap formed therein, and the air in the gap is not allowed to flow out to the outside.
The outer body absorbs radiation from the outer surface of the motor.

However, in conventional models, the heat generated by the motor is ultimately released into the internal space of the case that houses the entire machine tool, which is inefficient in maintaining the machine tool at a constant temperature, and the heat does not penetrate deep into the machine body. No consideration was given to heat transferred to the machine body from the outer surface of the motor shaft, which is often connected to the shaft on the main body side, and satisfactory temperature control could not be achieved.

Problems to be Solved by the Invention It is an object of the present invention to significantly improve heat countermeasures for motors, which have been a bottleneck in the conventional temperature control described above.

Means to solve the problem: The machine tool is housed in a case that covers the entire machine tool, and the motor connected to the machine tool is covered with a jacket made of heat insulating material, with a discharge space leading to the outside of the case between the outer periphery of the motor and the motor. , the front of the motor is fixed to the motor support part of the machine tool via a heat insulator, and the motor shaft is arranged with a gap between the support part and the heat insulator, and the heat insulator has an air pocket and a jet air supply path inside. The air pocket has an ejection hole opening into the discharge space, and a nozzle on an inner wall opposite to the ejection hole that communicates with the jet air supply path and faces the ejection hole. A communication gap actively formed at the contact point of the motor allows communication with the space around the motor.

Operation When the jet air from the nozzle passes through the ejection hole, the air in the air pocket is drawn out to the exhaust space by the Venduri effect, and the air around the motor shaft is sucked up through the communication gap due to the reduced pressure at that time, and the air around the motor shaft is Actively flow and discharge to the outside.

The air in the discharge space is quickly discharged to the outside of the case by the pressure of the jet air.

Embodiment FIG. 2 shows an example of an ultra-precision machine to which the present invention is applied. The machine tool 1 is housed in a synthetic resin case 2 that can be opened and closed and has a transparent upper part, and is almost completely shielded from the external environment during operation. It is now blocked. Although not shown, this machine tool has a constant temperature air supply device to the inside of the case as an external auxiliary device.
A constant-temperature pressure air supply device for air bearings and air joints, and an oil circulation device for a constant-temperature oil shower if necessary are included, forming a comprehensive system that maintains the entire machine tool at a constant temperature.

As shown in FIG. 3.4, the machine tool 1 includes a headstock 4 movable in the Z direction with respect to a base 3, a tool rest 5 movable in the X direction in front of the headstock 4, and a tool rest 5 on the tool rest 5. It is equipped with a rotary table 6 that rotates horizontally. An extendable cover 7 is provided in an area where the headstock 4 and tool rest 5 move in the Z-axis and X-axis directions in order to protect the sliding surface with the base 3 from chips and the like.

The headstock 4 is moved by driving the two-axis feed screw 8 that is mounted on the base 3 with the Z-axis servo motor M1, and the tool rest 5 is moved by driving the X-axis feed screw 9 that is mounted on the base 3 using the x@nervo motor M2. It is moved by driving. Further, the main spindle 4110 in the headstock 4 is driven by a main spindle motor M3, and the rotary table 6 is rotated by driving the worm 11 by a table rotation servo motor M4. The bearings of each axis, the headstock 4, the tool rest 50, and the sliding surface for the base 3 have a similar structure using static air bearings, static air support surfaces, or static pressure of oil to suppress heat generation and control movement. The smoothness of the process is ensured. The entire machine tool is placed and fixed on the bottom of the case 2 via an air damper 12 for vibration isolation.

A workpiece 13 attached to the main shaft 10 is an aspherical mirror used in Lehner equipment, and a diamond tool 14 is attached to the rotary table 6.

As shown in FIG. 1, all of the aforementioned motors M1 to M4 (represented by motor M), or at least the main shaft motor M3 and the table rotation servo motor M4, are covered with a jacket 15 made of a heat insulating material such as synthetic resin. The machine tool side support part (motor M1, M2
For motor M3, the motor mounting on the headstock 4 means a part, and for motor M4, the motor mounting on the tool rest 5 means a part. (represented by 17) is fixed with bolts.

An exhaust space is formed between the jacket 15 and the outer surface of the motor M, and a jet air supply path 19 and an air pocket 20 are formed inside the heat insulator 16. The jet air supply path 19 is connected to the jet air supply path 21 on the side of the support part 17, and the air pocket 20 is provided with an ejection hole 22 opening into the discharge space 18, and an inner wall portion facing the ejection hole 22 is provided with an air pocket 20. Said jet air supply path 1
A nozzle 23 communicating with the nozzle 9 is provided facing the ejection hole 22 . The air pocket 20 also includes a communication gap 2 that is actively formed in the area where the heat insulator 16 and the front surface of the motor M contact each other.
4 communicates with a space 26 around the motor shaft 25. A plurality of jet holes 22 and nozzles 23 are provided along the periphery of the motor M, and a jet air supply path 19 and a communication gap 24 are provided.
The air pockets 20 are formed in a radial shape, and the air pockets 20 are formed in an annular shape. Note that when the heat generation ω of the motor is large, a second blowout hole 22' may be provided in the heat insulator 16, in addition to the blowout hole 22, for blowing air directly from the jet air supply path 19 to the exhaust space 18. be.

The motor shaft 25 is connected to the feed screw 8 via an air joint 27.
, 9 are connected to the main shaft 10 and the arm 11. Reference numeral 28 denotes an air static pressure supply path formed in the support portion 17, which communicates with a small space 29 forming a static pressure air bearing of the bearing portion.

Note that air is supplied to the jet air supply path 19 and the air static pressure supply path 28 by separate systems because the required conditions are different, and the jet air supply path 19 is supplied with constant-temperature liquid instead of air. Sometimes it is done.

A cover cylinder 30 that is freely expandable and bendable is attached to the rear of the mantle 15, and directly communicates the discharge space 18 with the outside of the case 2.

When turning, the case 2 is closed, the above-mentioned comprehensive system for maintaining a constant temperature is operated, and compressed air is supplied to the jet air supply path 21 (on the supporting part side) through a cooling tube.
While jetting air from the nozzle 23 toward the jetting hole 22 through the jet air supply path 19 inside the heat insulator 16, each of the motors M1 to M4 is driven under NC or other predetermined control.

The main spindle is one M3, and the table rotation servo motor M4 moves while being connected to the case with the cover tube 30 as the main spindle f↑4 and the tool rest 5 move, but since the cover tube 30 is extendable and bendable, the headstock 4. There is no support for the movement of the tool stand 5. The above-mentioned comprehensive system suppresses heat generation from the shaft support and sliding portion of the machine body, and also discharges the heat generated by the motor to the outside, thereby maintaining the temperature inside the case and the temperature of the machine body constant. And nozzle 2
When the jet air from 3 passes through the nozzle hole 22, it also pulls out the air inside the near pocket 20 to the outside through the venturi effect, and the air in the space 26 around the motor shaft 25 passes through the communication gap 24 to the air as shown by the broken line in FIG. The air in the space 26 is forcibly drawn up into the air pocket 20 so as to show a flow of air, and the air in the space 26 is discharged to the exhaust space 18 without being retained, thereby removing the heat transferred from the motor shaft 25 to the machine body.

At the same time, the air in the exhaust space 18 in contact with the outer surface of the motor is also forcibly discharged to the outside through the cover pipe 30 along with the heat of the motor due to the action of the jet air.

Effects of the invention The heat generated by the motor is directly discharged to the outside of the case and does not affect the machine body of the machine tool.In particular, the heat around the motor shaft that has entered the machine body is also removed, reducing the effects of the heat generated by the motor. can be removed almost completely.

The jet air ejected from the nozzle sucks the air around the motor shaft and at the same time pushes out the air in the discharge space 18 to the outside, so the energy of the jet air can be used without wasting it.

[Brief explanation of the drawing]

Figure 1 shows the main part! FIG. 2 is a perspective view, FIG. 3 is a plan view with the lid of the case removed, and FIG. 4 is a schematic vertical sectional view. 1...Machine tool, 2...Case, 3...Base,
4... Headstock, 5... Tool stand, 6... Rotating double, 7... Cover, 8... Z transport screw, 9...
X-axis feed screw, 10... main shaft, 11... two A-m,
12... Air damper, 13... Work, 14...
・Diamond tool, 15... Mantle body, 16... Heat insulator, 17... Support part, 18... Ejection space, 1.
...Jet air supply path (of the heat insulator), 20...Air pocket, 21...Jet air supply path (on the support part side), 22...Blowout hole, 23...Nozzle, 24...・
Communication gap, 25... Motor shaft, 26... Space around motor shaft, 27... Air joint, 28... Air static pressure supply path, 29... Slight space, 30... Cover tube,
Ml... Z-axis servo motor, M2...

Claims (1)

[Claims] The machine tool is housed in a case that covers the entire machine tool, and each motor of the machine tool is covered with a jacket made of heat insulating material with a discharge space leading to the outside of the case between the outer periphery of the motor and the front of the motor. The motor shaft is fixed to the motor support part via a heat insulator, and the motor shaft is arranged with a gap between the support part and the heat insulator, and the heat insulator has an air pocket and a jet air supply path inside, and the air pocket has the air pocket as described above. A nozzle that communicates with the jet air supply path and faces the nozzle is provided on an internal wall at a position opposite to the nozzle opening into the discharge space, and is actively formed at the contact point between the heat insulator and the motor. An ultra-precision machine tool characterized by communicating with the space around the motor shaft through a communication gap.