JPH11280691A - Vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum pump which can prevent the motor coil from deterioration or the motor from thermal damage by increasing the contacting performance between the motor in the pump and the pump housing so as to dissipate heat of the motor outside. SOLUTION: A turbine blade is formed with a fixed blade element 3 installed via a spacer 4 inside the case 10 and a blade element 2 for exhaust which is installed to the driving shaft 1 opposed to the fixed blade element 3. The blade element 2 for exhaust is rotated at a high speed by a high frequency motor 33 against the fixed blade element 3, gaseous molecules taken in from the inlet port 5 are discharged to the discharge port 6. Between a housing 40 to be a base of the pump and the high frequency motor 33, a thermal conductive elastic element 41 is disposed. This prevents deterioration of the motor coil and thermal damage of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vacuum pump for obtaining a high vacuum or an ultra-high vacuum.

[0002]

2. Description of the Related Art For example, turbo-molecular pumps, which are a kind of vacuum pumps, rotate these rotor blades alternately arranged with stator blades in a rotor chamber (vacuum chamber) at a high speed, and impinge on these gas turbines. A gas flow is forcibly generated by the mechanical exhaust action of the cascade, and is characterized by the ability to obtain an ultra-high vacuum.

Heat sources inside the pump include a motor for rotating the rotor blades at high speed, an electromagnet for supporting the shaft by magnetic levitation, and a frictional heat generated by viscous resistance of the exhaust fluid with the rotating body. is there.

[0004]

In particular, among the above-mentioned heat sources, if the pump is driven for a long time, the motor generates heat with its own power consumption, and the inside of the turbo molecular pump is in a vacuum state. The heat cannot be dissipated through the heater and the temperature rises. The motor body is pressed into the housing of the pump or fixed to the housing with a set screw or the like. However, the entire surface is not completely in contact with the housing, and if there is a gap, a vacuum insulation state is obtained.

Further, when the temperature rises, the gap between the motor body and the pump housing expands due to the difference in the thermal expansion rate between the motor body and the pump housing. Further, the heat transfer worsens, and the heat of the motor is accumulated. And burnout of the motor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and enhances the adhesion between a motor in a pump and a pump housing, diffuses heat generated by the motor to the outside, and causes deterioration of a motor coil and motor. It is an object of the present invention to provide a vacuum pump capable of preventing burnout of a vacuum pump.

[0007]

In order to achieve the above object, a vacuum pump according to the present invention comprises a rotor having exhaust wings, and a vacuum pump having a motor for rotating the rotor. A heat conductive elastic body is provided between the pump housing and the pump housing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing the structure of a turbo molecular pump which is a kind of the vacuum pump of the present invention.

This pump main body is mainly composed of a housing 40 and a case 10 made of an aluminum alloy. A turbine blade is formed by the fixed blade body 3 attached to the inside of the case 10 via the spacer 4 and the exhaust blade body 2 attached to the drive shaft 1 and opposed to the fixed blade body 3, and fixed. The exhaust wing 2 is rotated at a high speed by the high frequency motor 33 with respect to the wing 3, and the gas molecules taken in from the intake port 5 are compressed and exhausted to the exhaust port 6.

A drive shaft 1 for rotating the rotor 11 provided with the exhaust wings 2 at a high speed is supported in a non-contact manner. A magnetic bearing for supporting the drive shaft 1 in a non-contact manner is provided in a radial direction of the drive shaft 1. Magnetic bearings 34a and 34b provided with electromagnets
And a thrust magnetic bearing 34c provided with an electromagnet in the axial direction. A radial sensor 31a for detecting the state of the drive shaft 1 and a displacement sensor 31b such as a thrust sensor are installed at substantially the same position as the electromagnet. In addition, the position of the drive shaft 1 in the thrust direction is detected, and the attractive force of each electromagnet is adjusted to support the drive shaft 1 at the center position.

The high-frequency motor 33 has a configuration in which the oscillation frequency and the output voltage can be varied, and the rotor 11 is made of a metal such as an aluminum alloy to withstand high-speed rotation.

By the way, as described above, the main body of the pump body, the housing and the case are made of an aluminum alloy having a good thermal conductivity. On the other hand, a silicon steel plate or the like is usually used for a high-frequency motor or a magnetic bearing in order to reduce eddy current loss.

Here, when the flow rate of the gas flowing from the intake port 5 is large, the high-frequency motor 33 is used to maintain the rotation.
Power is required, and the amount of heat generated increases. Normally, the high-frequency motor 33 is simply pressed into the housing 40 or fixed to the housing with a set screw or the like, so that the high-frequency motor 33 is not completely in close contact, and the heat generated in the high-frequency motor 33 is completely external. Since the gas does not escape to the high-frequency motor, the temperature of the high-frequency motor rises.

When the temperature rises, there is a difference in the coefficient of thermal expansion between the high-frequency motor 33 made of a silicon steel plate or the like and the housing 40 made of an aluminum alloy or the like. Conventionally, heat is hardly dissipated. In the present invention,
By inserting a thermally conductive elastic body 41 such as an epoxy resin between the high frequency motor 33 and the housing 40, the heat generated from the high frequency motor 33 is continuously radiated.

The heat conductive elastic body 41 is provided with the high frequency motor 3
3 is inserted so that the entire surface of the portion of the stator 3 and the housing 40 are in close contact with each other.
1, the heat-generating elastic body allows the heat generated by the high-frequency motor 33 to be continuously radiated to the outside via the elastic body 41 and the housing 40.

The use of the elastic body also has the effect of damping the vibration caused by the rotation of the motor.

In the above embodiment, a turbo molecular pump is taken as an example, but the present invention can be applied to all vacuum pumps such as a drag pump.

An elastic body such as rubber may be used instead of an epoxy resin, and any other material that can form a close contact state and has good heat conductivity may be used.

[0020]

As described above, according to the present invention, since the heat conductive elastic body is provided between the motor and the housing, even if the temperature rises, the gap between the motor and the housing is increased. Does not occur, and the heat generated in the motor is kept radiated to the outside, so that the motor can be prevented from being burned and deteriorated.

Further, by using the elastic body, the vibration generated by the rotation of the motor can be damped, and the influence of the reduced vibration generated by the pump on the equipment connected to the vacuum pump can be reduced. The pump used has a longer bearing life.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

Claims (1)

[Claims] 1. A vacuum pump having a rotor having exhaust wings and a motor for driving the rotor to rotate, wherein a thermally conductive elastic body is provided between the motor and the pump housing. Vacuum pump to do.