JPH05227700A - Claw-pole type motor - Google Patents

Abstract

PURPOSE:To provide a claw-pole type motor in which cooling is performed positively with reduced power consumption. CONSTITUTION:A spiral groove 14 for forming cooling gas 10 flow in the direction from one end side to the other end side of a rotary shaft 1 through rotation of the rotary shaft 1 is formed in at least one of the outer peripheral surface of the rotary shaft 1 of a claw-pole type motor or the inner peripheral surface of casing flange 15 surrounding the rotary shaft 1 and a cooling gas circulation passage 16 equipped with a gas cooler 13 connects one and the other ends of the rotary shaft 1.

Description

Detailed Description of the Invention

[0001]

The present invention relates to helium He, hydrogen H ₂
The present invention relates to a claw pole type electric motor used in a cryogenic liquefaction refrigeration turbo compressor or the like.

[0002]

2. Description of the Related Art A low temperature turbo compressor for liquefying helium needs to give kinetic energy to a very light helium gas to compress it. Therefore, a driving motor is of a claw pole type because it requires high speed.

In a conventional normal synchronous electric motor or the like, the rotor provided at the axial center of a stator formed in an annular shape has the following structure.
It has a structure in which a large number of laminated plates and a large number of copper bars, etc. are attached to the outer circumference of the rotating shaft, and therefore, when rotating at a high speed, a load based on a very large centrifugal force is applied to the rotor assembly. This will cause a problem in strength. On the other hand, the claw pole type electric motor does not have such an assembly and has an integrated structure suitable for high speed rotation.

FIG. 4 shows an example of a conventional claw pole type electric motor. A stator 2 is provided so as to surround the outer circumference of a rotary shaft 1, and a field coil is provided so as to sandwich the stator 2 in the axial direction. 3 is attached, and the magnetic field generated by the field coil 3 is transmitted to the rotary shaft 1 through the casing flange 15, so the rotary shaft 1 separates the magnetic material and the N and S poles. It has a one-piece structure formed by molding a magnetic material. Therefore, the claw pole type electric motor can greatly increase the strength of the rotating shaft 1, and can be said to be suitable for high speed rotation. 4 is an impeller of a turbo compressor 5 attached to the rotary shaft 1 for compressing helium gas, 6 is a journal magnetic bearing, 7 is a thrust magnetic bearing, 8 is a liquefied nitrogen inlet for cooling the stator, and 9 is a guide. Indicates the exit.

On the other hand, since the claw pole type motor rotates at a high speed, the heat generation density based on the frictional heat of the cooling gas, the hysteresis loss of the iron core and the conductor resistance is larger than that of a normal motor, and even if it is small in appearance, the temperature is small. It is necessary to perform forced cooling because the temperature rises sharply.

For this reason, conventionally, as shown in FIG. 4, a part of the compressor discharge gas (helium gas) is introduced from the back surface of the impeller 4 of the turbo compressor 5 into the electric motor as the cooling gas 10, and along the rotating shaft 1. To cool the rotating shaft 1 and the inner surface of the stator 2 and the like, and then pass the heated cooling gas 10 through the orifice 11 for adjusting the flow rate, and then exchange heat with the liquefied nitrogen and the like via the pipe 12. Then, the gas is guided to the gas cooler 13 for cooling, and the turbo compressor 5 is made to suck again.

[0007]

However, in order to cool the electric motor, it is necessary to flow a considerable amount of cooling gas 10.
In the conventional method, since a part of the gas compressed by the turbo compressor is used as the cooling gas 10, the amount of compressed gas and power consumption increase, and the efficiency of the turbo compressor 5 decreases. Had a problem.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a claw pole type electric motor capable of performing reliable cooling and reducing power consumption for cooling.

[0009]

According to the present invention, at least one of an outer peripheral surface of a rotary shaft of a claw pole type electric motor and an inner peripheral surface of a casing flange surrounding the rotary shaft is rotated by rotation of the rotary shaft. A cooling gas circulating flow that forms a spiral groove that forms a flow of cooling gas from one end side to the other end side of the shaft, and has a gas cooler in the middle between one end side and the other end side of the rotating shaft. The present invention relates to a claw pole type electric motor characterized by being connected by a road.

[0010]

When the claw pole type motor is driven, the rotation of the rotary shaft causes the spiral groove formed on at least one of the outer peripheral surface of the rotary shaft and the inner peripheral surface of the casing flange to move from one end side to the other end side of the rotary shaft. An oncoming cooling gas flow is formed to cool the electric motor. The cooling gas whose temperature has risen due to cooling is cooled by a gas cooler provided in the cooling gas circulation passage and is again guided to one end side of the rotating shaft. The flow rate of the cooling gas can be selected by selecting the number of spiral grooves, the cross-sectional shape, and the lead angle.

[0011]

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

FIG. 1 shows an example of a claw pole type electric motor according to the present invention. In the figure, the parts denoted by the same reference numerals as those in FIG. 4 represent the same parts, and detailed description thereof will be omitted.

As shown in FIG. 2, the flow of the cooling gas 10 from one end side to the other end side of the rotating shaft 1 by the rotation of the rotating shaft 1 is caused on the outer peripheral surface of the rotating shaft 1 of the claw pole type electric motor of FIG. A plurality of parallel spiral grooves 14 that are to be formed are formed. The number, cross-sectional shape, lead angle, axial length, etc. of the spiral groove 14 can be arbitrarily designed according to the flow rate of the cooling gas 10 required for cooling and the resistance of the entire flow path. Further, since the casing flange 15 serving as the magnetic path of the field coil 3 is located on both sides in the axial direction with the stator 2 interposed therebetween, the spiral groove 14 is provided adjacent to one casing flange 15 on the rotary shaft 1 or both casings. It may be provided on the rotary shaft 1 adjacent to the flange 15. FIG. 1 shows an example provided on both sides.

On the way between the position of the journal magnetic bearing 6 on one end side of the rotary shaft 1 opposite to the turbo compressor 5 side and the position of the journal magnetic bearing 6 on the other end side of the rotary shaft 1 on the turbo compressor 5 side. Are connected by a cooling gas circulation flow path 16 equipped with a gas cooler 15. As the cooling gas 10,
The same helium gas as the gas compressed by the turbo compressor 5 is used. In the figure, 17 is a cooling gas inlet, 18 is a cooling gas outlet, and 19 is an air gap.

When the rotary shaft 1 provided with the spiral groove 14 starts to rotate, the cooling gas 10 in the spiral groove 14 is discharged in the flow axis direction along the spiral groove 14 due to inertia and viscosity.

Since the cooling gas 10 flowing into the spiral groove 14 is cooled by the gas cooler 13 and has a lower temperature than the components inside the electric motor, it absorbs heat in the process of flowing along the rotating shaft 1 inside the electric motor and outside the electric motor. Is discharged to. The discharged cooling gas 10 is cooled by the gas cooler 13 and is circulated and used again. By repeating this process, the electric motor is constantly cooled by the heat generation and can maintain a constant temperature.

At this time, since the outlet of the impeller 4 communicates with the inside of the electric motor, the pressure of the cooling gas 10 is governed by the outlet pressure of the impeller 4 and may vary depending on operating conditions, but the amount of the cooling gas 10 is small. Therefore, equilibration takes place in an extremely short time, and fluctuations in the cooling gas flow due to pressure fluctuations do not adversely affect the cooling effect.

FIG. 3 shows another embodiment of the present invention.
Instead of forming the spiral groove 14 on the rotary shaft 1, the spiral groove 14 is formed on the inner peripheral surface of the casing flange 15.

Also in the embodiment of FIG. 3, the electric motor can be cooled by the same operation as in FIGS.

The present invention is not limited to the above-mentioned embodiment, but the position where the spiral groove is provided can be arbitrarily selected, and various modifications are made within the scope not departing from the gist of the present invention. Of course you can get it.

[0021]

According to the above-described claw pole type electric motor of the present invention, the spiral groove formed on at least one of the outer peripheral surface of the rotary shaft and the inner peripheral surface of the casing flange allows one end side to the other end side of the rotary shaft. Since the electric motor is cooled by forming the flow of the cooling gas toward the air and circulating the cooling gas, the gas compressed by the compressor is not used for cooling, and therefore the compressor is not used. The efficiency can be improved, and the power required to circulate the cooling gas can be suppressed to be small.

[Brief description of drawings]

FIG. 1 is a cut front view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part showing another embodiment of the present invention.

FIG. 4 is a cut front view showing an example of a conventional claw pole type electric motor.

[Explanation of symbols]

 1 rotating shaft 10 cooling gas 13 gas cooler 14 spiral groove 15 casing flange 16 cooling gas circulation flow path

Claims (1)

[Claims] 1. At least one of an outer peripheral surface of a rotating shaft of a claw pole type electric motor and an inner peripheral surface of a casing flange surrounding the rotating shaft is rotated from one end side to the other end of the rotating shaft by rotation of the rotating shaft. A spiral groove that forms a flow of the cooling gas toward the side is formed, and one end side and the other end side of the rotating shaft are connected by a cooling gas circulation flow path provided with a gas cooler in the middle. Claw pole type electric motor.