JP2000179498A - Electric turbo instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric turbo instrument capable of preventing a damage caused by a softening deformation of a motor rotator conductor caused by a temperature rising due to a loss of the motor rotator and being safely operated. SOLUTION: A lubrication oil which lubricated an upper bearing 6 is collected on an oil receiver 5 and is made to flow down to a motor rotator 4b (particularly end ring 4C of a conductor). A temperature of a rotator 4B by aggressively heat-releasing to the lubrication oil. The lubrication oil which cooled the motor rotator 4B and of which the temperature rose is returned to an oil reservoir 10 through oil return passages 8, 9 and a heat-releasing is carried out from the oil to a housing. Thus, a damage caused by a temperature rising due to a heat-generation of the motor rotator 4B can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric turbo machine (compressor / blower) in which a turbine wheel is driven at a high speed by an internal motor.

[0002]

2. Description of the Related Art In a gas laser apparatus which is practically used for continuously obtaining a high-power laser, for example, carbon dioxide gas and another gas are mixed, guided to a laser tube, discharge-excited, and resonated. At this time, the temperature of the gas rises, so the gas is circulated and cooled through the heat exchanger. An electric turbo blower is used to circulate this gas.

FIG. 4 shows a configuration of a conventional electric turbo blower. In the turbo blower 51, an impeller 52 and a motor rotor 54 </ b> B are axially mounted on a shaft 53, and are supported by bearings 56 and 57 provided on an upper portion and a lower portion of a housing 67. The motor 54 rotates at high speed when excited by the variable frequency inverter 65, and drives the impeller 52 to rotate. The gas sucked in from the suction port Pin by the rotation of the impeller 52 is compressed and led out from the outlet Pout.

The shaft 53 has a concentric shaft hollow hole 6.
2, a hollow centrifugal pump section 61 having a slope is formed at a lower portion thereof. The centrifugal pump section 61 is immersed in the oil reservoir 60, and the rotation of the shaft 53 causes the lubricating oil filled in the oil reservoir 60 to be pumped up along the inner wall of the shaft hollow hole 62. Holes 63 and 64 are formed in the shaft 53 above bearings 56 and 57 and communicate with the shaft hollow hole 62. Lubricating oil pumped up along the inner wall of the hollow hole 62 is rotated by rotation of the shaft 53. It is discharged from the holes 63 and 64 to the upper portions of the bearings 56 and 57 by centrifugal force, and lubricates the bearings 56 and 57. The lubricating oil that has lubricated the bearings 56 and 57 is returned to the oil return paths 58 and 59 by gravity.
Back to 60 for oil. The lubricating oil exists in a spray state and a circulating state in the space 69 of the motor drive unit. Leakage of the lubricating oil into the gas compressor 70 is prevented by a seal mechanism 68 such as a labyrinth seal. Further, in order to prevent the lubricating oil from leaking into the gas compression section 70, the space 69 in the motor drive section is
Is connected to a vacuum pump by a line through a hole 66 so as to be kept at a low pressure with respect to the vacuum pump.

[0005]

The conventional electric turbo blower is configured as described above. However, when the motor for driving the impeller is operated, the stator and the rotor each generate a loss and generate heat. The heat generated by the loss of the stator can be reduced by installing a cooling means such as a water-cooled jacket on the housing.However, the heat generated by the loss of the rotor is transferred from the bearing to the housing via the shaft and from the rotor. Heat is released from the impeller to the gas, but if the gas is lean, it cannot be actively cooled. For this reason, the temperature rise of the rotor becomes remarkable, and the aluminum end ring, which is the secondary conductor of the rotor, becomes hot and softens and deforms.
Damage can occur. The present invention has been made in view of such circumstances, and an electric turbocharger that can cool a conductor of a motor rotor using lubricating oil provided for lubrication of a bearing and prevent damage to the rotor. The purpose is to provide equipment.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an electric turbo apparatus according to the present invention comprises a rotating body comprising a motor rotor and a drive shaft on which a turbine wheel is axially mounted. A pair of upper and lower bearings, a lubricating oil supply pump for lubricating the bearings and a lubricating oil flow path are provided in the drive shaft, and the shaft end of the drive shaft is immersed for lubricating oil, and the drive shaft rotates. Thus, in the electric turbo apparatus in which lubricating oil is raised in the drive shaft by the pump and lubricating oil is supplied from a hole drilled in a bearing portion of the drive shaft, lubricating the upper bearing, An electric turbo device is configured to collect lubricating oil in a process of returning to a reservoir, etc., to a conductor forming a secondary winding of a motor rotor, and to cool the motor rotor conductor. .

[0007]

FIG. 1 is a block diagram showing an embodiment of an electric turbo device provided by the present invention. Turbo blower 1
The impeller 2 and the motor rotor 4B are axially mounted on the shaft 3, and the bearings 6 disposed on the upper and lower parts of the housing 17,
7. The motor 4 is rotated at high speed by being excited by the variable frequency inverter 15, and drives the impeller 2 to rotate. The gas sucked from the suction port Pin by the rotation of the impeller 2 is compressed and is compressed at the outlet Pout.
Is derived from

The shaft 3 is concentric with the hollow hole 12 in the shaft.
And a hollow centrifugal pump unit 11 having a slope is formed at a lower portion thereof. The centrifugal pump section 11 is immersed in the oil reservoir 10, and the rotation of the shaft 3 causes the lubricating oil filled in the oil reservoir 10 to be pumped up along the inner wall of the shaft hollow hole 12. In addition, holes 13 and 14 are formed in the shaft 3 above the bearings 6 and 7 so as to communicate with the shaft hollow hole 12.
The lubricating oil pumped up along the inner wall of the hollow hole 12 is centrifugally driven by the rotation of the shaft 3 so that
3 and 14 are discharged to the upper portions of the bearings 6 and 7 and the bearings 6 and 7
Lubricate. The lubricating oil that has lubricated the bearings 6 and 7 returns to the oil reservoir 10 through the oil return paths 8 and 9 due to gravity. This lubricating oil exists in a spray state and a circulating state in the space 19 of the motor drive unit. Leakage of the lubricating oil into the gas compression section 20 is prevented by a seal section 18 such as a labyrinth seal. Further, in order to prevent the lubricating oil from leaking into the gas compression section 20, the space 19 of the motor drive section is connected to the vacuum pump through a line from the hole 16 so as to maintain a low pressure with respect to the gas compression section 20. .

The motor 4 has a variable frequency inverter 15
In general, the induction type motor which is often used has an efficiency of 80 to 90% and an input power of about 10%.
20% is lost and generates heat. About 2/3 of the loss is caused by the stator 4A, and the remaining about 1/3 is caused by the rotor 4B. For example, in a motor of 7.5 KW and an efficiency of 85%, a loss of about 750 W occurs in the stator 4A and about 375 W occurs in the rotor 4B, thereby generating heat. The heat generated by the stator 4A is radiated to the housing 17 as described above. On the other hand, heat generated by the rotor 4B is transmitted from the shaft 3 to the gas flowing through the impeller 2, from the shaft 3 to the housing 17 via the bearings 6, 7, and from the surface of the rotating body to the housing 17 and the like. Although the heat is radiated by the radiation, the impedance of the heat transfer path is high and the heat transfer path cannot be sufficiently transmitted.
The temperature of B rises. The most commonly used rotor of a squirrel-cage induction motor uses aluminum as the conductor,
A cage-shaped secondary winding is formed by casting in the groove of the iron core. The deformation temperature of aluminum under high stress is 300 to 350 ° C.
If the heat radiating means of the rotor 4B is not provided, a temperature rise exceeding this temperature occurs and the rotor 4B is broken.

For this reason, in the embodiment of FIG. 1, the lubricating oil which has lubricated the upper bearing 6 is collected in the oil receiver 5, and is allowed to flow down to the motor rotor 4B (particularly, the end ring 4C of the conductor). By radiating heat to the lubricating oil, the temperature of the rotor 4B (end ring 4C) can be sufficiently lowered to a safe temperature lower than the softening deformation temperature. The lubricating oil whose temperature has risen by cooling the motor rotor 4B returns to the oil reservoir 10 through the oil return paths 8, 9, and is radiated from the oil to the housing. In this way, it is possible to prevent the motor rotor 4B from being damaged due to a rise in temperature due to heat generation.

FIG. 2 shows another embodiment of the present invention. As shown in FIG. 2, the side face of the end ring 4C of the motor rotor 4B facing the shaft 3 is inclined so as to make the opening larger. The lubricating oil collected by the oil receiver 5 and lubricating the bearing 6 flows down between the end ring 4C and the shaft. In this case, the rotor 4
Since the lubricating oil absorbs heat from the end ring 4C while rotating on the slope of the end ring 4C by the rotation of B,
The cooling of the rotor 4B (end ring 4C) can be effectively performed.

FIG. 3 shows still another embodiment of the present invention, in which an end ring 4C constructed in the same manner as in FIG. 2 has a plurality of pores extending from the inner surface (the shaft 3 side) to the outer surface (the stator 4A side). It is perforated and provided with a passage for lubricating oil. As a result, the lubricating oil that has flowed down between the shaft 3 and the end ring 4C rises on the slope of the end ring 4C by the rotation of the motor 3, and a part of the lubricating oil flows out of the pores to the outer surface due to centrifugal force. Since heat is absorbed from the ring 4C, the end ring 4C can be cooled more effectively.

In the above embodiment, the impeller 2 is shown as a centrifugal impeller, but may be another impeller shape, for example, an axial impeller. Further, in the above embodiment, the centrifugal pump having the slope for pumping the lubricating oil from the lower portion of the shaft hollow hole 12 to the hollow hole is shown, but another type of pump may be used. Further, although the oil receiver 5 is shown as a separate component from the housing 17, it is also possible to adopt a structure in which lubricating oil that lubricates the bearing 6 is collected integrally with the housing 17 and flows down to the end ring 4C.

[0014]

The electric turbo device of the present invention is constructed as described above, and collects lubricating oil that has lubricated the upper bearing and flows down to the end ring of the conductor of the motor rotor, thereby generating heat of the rotor. Thereby, the end ring which may be softened and deformed and damaged is effectively cooled, and the electric turbo device can be operated in a safe temperature range.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of an electric turbo device according to the present invention.

FIG. 2 is a view showing an embodiment of a shape of a motor rotor end ring according to the second aspect of the present invention;

FIG. 3 is a view showing an embodiment of a shape of a motor rotor end ring according to the third aspect of the present invention.

FIG. 4 is a diagram showing a configuration of a conventional electric turbo device.

[Explanation of symbols]

1 ... Turbo blower 2 ... Impeller 3 ... Shaft 4 ... Motor 4A ... Stator 4B ... Rotor 4C ... End ring 5 ... · Oil receiver 6,7 ··· Bearing 8,9 ··· Oil return path 10 ··· For oil 11 ··· Centrifugal pump section 12 ··· Shaft hollow hole 13,14
············································ Inverter 17 ························································································
exit

Claims (3)

[Claims] 1. A rotating body comprising a drive shaft on which a motor rotor and a turbine wheel are axially mounted, a pair of upper and lower bearings supporting the rotating body, a pump for supplying lubricating oil for lubricating the bearings, and a lubrication system An oil flow path is provided in the drive shaft, the shaft end of the drive shaft is immersed for lubricating oil, and the drive shaft rotates, whereby the lubricating oil rises in the drive shaft by the pump, and In an electric turbo device in which lubricating oil is supplied from a hole drilled in a bearing portion, an oil receiver is provided above the motor rotor to lubricate the upper bearing and lubricate in a process of returning to the oil reservoir. An electric turbomachine which collects oil and guides it to a conductor forming a secondary winding of the motor rotor so that the motor rotor conductor can be cooled by lubricating oil. 2. The electric turbo apparatus according to claim 1, wherein a side surface of the end ring of the motor rotor facing the drive shaft has a slope and is opened at an upper portion. 3. A motor rotor, wherein a side surface of the end ring facing the drive shaft of the motor rotor is inclined so as to open upward, and a plurality of end rings extend from the drive shaft side to the stator-facing side. The electric turbo device according to claim 1, wherein a hole is provided.