JPS5866550A - Vacuum protecting device for motor - Google Patents

Abstract

PURPOSE:To prevent the damage of a motor by enclosing the motor with a casing, sealing the mounting portion and the shaft portion of the motor and controlling the air characteristic in the casing, thereby eliminating the limit of the output of the motor. CONSTITUTION:A motor 1 is enclosed with a casing 3 released at the flange end, the casing side 3 and a motor rotational shaft 12 side are mounted on a motor holder 2, thereby cantilevering the motor 1, and a coupling 11a is inserted into the shaft 12. An oil seal 9 of a movable seal is provided between the outer periphery of the coupling 11a and the inner periphery of the holder 2, and collar 13 inserted with O-ring 17, 18 is arranged at the inserting portion of the shaft 12 to the coupling 11a. Further, a pressure detecting pipe 4 is installed at the outer periphery of the casing 3, a valve 5 is opened due to the decrease in the pneumatic pressure in the casing 3, and air is introduced into the casing 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum protection device for an electric motor that protects an electric motor driven in a vacuum from vacuum and prevents damage to the electric motor.

Electron beam technology, thin film technology for LSI, etc. require a process of transporting objects in a vacuum. Further, electron beam machining, electron beam welding, electron beam heat treatment, etc. also require moving jigs and the like in a vacuum. And these require electric motors. In electric motors, two commutators are used to pass current through the rotor coil. When the electric motor is driven in the atmosphere, an oxide film is formed on the surface of the commutator to prevent abnormal wear between the commutator and the rotating shaft. However, when an electric motor is driven in a vacuum, no oxide film is formed on the surface of the commutator, resulting in an increased coefficient of friction and abnormal wear. Additionally, when the motor armature voltage is high, arcing occurs between the commutator and its casing, resulting in a short circuit. Additionally, poor heat dissipation often causes the commutator to melt.

For this reason, electric motors are not normally used in a vacuum. However, as mentioned above, it is necessary to use the electric motor in a vacuum, and vacuum protection of the electric motor is required.

When an XY table is used in an electron beam processing machine or an electron beam welding machine, a vacuum chamber covering the XY table is surrounded by an operation console on the front side and an evacuation device on the rear side. Therefore, the electric motor of the XY table cannot be taken out to the front or rear side of the vacuum chamber. Furthermore, even if the electric motor of the XY table is taken out of the vacuum chamber, it is undesirable to separate the lead screw shaft of the ruling table connected to the electric motor from the electric motor, which is extremely disadvantageous in terms of maintenance. . Therefore, normally, (only) the XY01 axis is placed in a vacuum chamber, and the output is kept low for the above-mentioned reason. Therefore, when the load is too heavy, the time constant becomes too steep, resulting in a disadvantage that quick driving cannot be performed.

The present invention was proposed in order to eliminate the drawbacks of the prior art based on the above requirements, and the purpose is to provide a motor that can be driven in a vacuum without limiting its output and that does not cause damage to the motor. To provide vacuum protection equipment.

In order to achieve the above objects, the present invention covers an electric motor with a casing to isolate the electric motor from a vacuum chamber, and connects the inside of the casing to the vacuum chamber through a gap between a mounting portion of the electric motor and an electric shaft portion of the electric motor. The present invention is characterized by a vacuum protection device for an electric motor, which is sealed to prevent electrical conduction between the casing and the casing, and the air characteristics within the casing are controlled by a regulating device.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a motor 1 is enclosed by a casing 3 with its Franz end open and isolated from the vacuum. Therefore, the space inside the casing 3 is filled with air. The motor rotating shaft 12 side of the motor 1 and the casing 3 are attached to a motor holder 2 and held in a cantilevered manner. The electric motor holder 2 is supported by a mounting base 16 on the machine body side. Note that an O-ring 8 is interposed between the casing 3 and the motor holder 2 to prevent air leakage. A coupling lla is inserted into the motor rotating shaft 12 and fixed with a nut 15a.

The screw shaft 14 is also screwed into the screw ring 1 by the nut 15b.
1bK is fixed, coupling lla and 11bid ha□
The connection is made through a coupling or the like.

An oil seal 9, which is a movable seal, is inserted between the outer circumference of the coupling lla and the inner circumference of the electric motor holder 2.
It is held by a seal presser 10.

The movable seal is used here to ensure sealing and smooth rotation of the motor.

As shown in detail in FIG. 2, a collar 13 is provided at the insertion portion between the motor rotating shaft 12 and the coupling lla. The collar 13 is screwed onto the coupling lla by a delt 19, and is formed so as to maintain a small gap from the motor rotating shaft 12. Q IJ rings 17 and 18 are inserted into the minute gap to prevent air leakage within the casing 3.

The oil seal 9 and O-ring 17°18 explained above
Otherwise, the electric motor 1 is completely isolated from the external atmosphere in a vacuum state.

A valve 5 and pressure detection piping 4 are installed on the outer circumferential side of the casing 3.
is installed, and the pressure detection piping 4 is connected to the pressure detector. Air is supplied from the valve 5 into the casing 3 and sealed therein.

When the air pressure inside the casing 3 decreases while the electric motor 1 is in use, the electrical contacts of the pressure detection piping close, and a warning lamp (or LED, not shown) attached to the tip of the electric cable 20a lights up. . This lighting causes the oiler to open the valve 5 and introduce air.

In this embodiment, a diaphragm pressure switch is used as the electrical contact, but of course the present invention is not limited to this.

Furthermore, although the operation of detecting a drop in air pressure and introducing air through the valve 5 was carried out manually by the operator in this embodiment, it is also possible to carry out these operations under automatic control.

In FIG. 3, electric motor 1 is connected to an XY table 22. In FIG. Although it is disposed within the vacuum chamber 21, it is isolated from the vacuum chamber/bar 21 by the casing 3 as described above.

Electric wiring 6 is connected to the electric motor 1 with a sufficient margin, and the electric wiring 6 is kept airtight by vacuum connectors 7a and 7b.

An exit side flexible bellows tRif23 and an input side flexible bellows are connected to the casing 3. These pipes pass through the vacuum chamber 21 and communicate with an external air source (compressor) not shown.

Also, the flexible bellows on the entrance/exit side ze f23 +
Although not clearly shown in the drawings, airtightness prevention measures are applied to the portion where 24 penetrates the vacuum chamber 21 and the portion where it connects to the casing 3. Also, these pipes n, 24
is made long enough to allow the XY table to move.

Air sent from an air source such as a compressor is introduced into the casing 3 from the inlet side flexible perozino 2 f24, and 'c! Cool the 4III machine to an appropriate temperature and attach the flexible bellows on the exit side? Izo okara is discharged.

The temperature control inside the casing 3 is particularly illustrated.
Although not included, it is of course possible to install an appropriate temperature detection device to control the temperature.

The above embodiment provides the following effects.

That is, damage such as arc discharge, oxide film loss, and commutator loss due to low heat transfer can be prevented, and the motor can be operated at high speed without restricting the motor output even in a vacuum. Incidentally, in the prior art, abnormal discharge was observed in the motor at about 45V, but in this example, even when used at the maximum input voltage of 70V, there was no abnormal discharge and normal operation was possible. Therefore, in the past, the motor rotation speed was
．． ．． Although it was driven at 200 r, p, m, in this example, it was possible to operate at 3.00 or, p, m.

As is clear from the above description, according to the present invention, the electric motor can be operated in a vacuum without limiting its output, and the electric motor can be effectively prevented from being damaged.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the configuration of an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an airtight maintenance mechanism of the rotating part, and FIG. 3 is an explanatory diagram showing an air circulation mechanism in the casing of the embodiment. . DESCRIPTION OF SYMBOLS 1... Electric motor, 2... Electric motor holder, 3... Casing, 4... Pressure detection piping, 5... Pulp,
6... Electric wiring, 7 a, 7 b-... Vacuum connector, 8.17.18... 0 ring, 9... Movable seal, 10... Seal holder, 11a, Ilb...
Coupling, 12... Motor rotation shaft, 13... Collar, 14... Screw shaft, 15a, 15b...
Nut, 16...Mounting base, 19...Delt, addition...
・Pressure detector, 20a... Electric cable, 21...
Vacuum chamber, η...XY table, n...Flexible bellows on the exit side, Y...Flexible bellows on the input side. Agent Patent Attorney Tadashi Akimoto Minoru 1st Ward 2 16

Claims (1)

[Scope of Claims] 1. A vacuum protection device for protecting an electric motor of a machine body driven in a vacuum from vacuum, comprising: a casing enclosing the electric motor with an appropriate space in between; and a casing placed on the side of the machine body. a motor holder that holds and cantilever-supports the electric shaft side of the electric motor; a seal interposed between the outer periphery of a coupling ring inserted into the electric shaft and the inner periphery of the electric motor holder; and the coupling and a seal inserted therein. A vacuum protection device for an electric motor, comprising: a seal that prevents air leakage at a portion where the electric shaft is inserted; and an adjustment device that controls air characteristics existing within the casing. 2. The vacuum protection device for an electric motor according to claim 1, wherein the adjustment device is a pressure control device that maintains the air pressure within the casing to a constant value. 3. The vacuum protection device for an electric motor according to claim 1, wherein the adjustment device cools the electric motor by circulating air within the casing.