JP2001173591A - Electric turbomachinery - Google Patents

Abstract

(57) Abstract: An electric turbomachine that can safely operate by preventing a bearing that supports a rotating body from becoming hot due to frictional loss and being damaged is provided. An impeller (2) of a turbo blower (1) and a rotor (4B) of a motor are axially mounted on a shaft (3) to form a rotating body, and the rotating body is rotated by bearings (6, 7) disposed at an upper part and a lower part of a housing (17). Supported. 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 by the outlet Pou.
It is discharged from t. At this time, cooling water passages 23 and 24 are provided in the vicinity of the bearings 6 and 7 in the housing 17 to cool the outer ring of the bearing, thereby lowering the temperature of the bearing rotating at high speed and preventing the bearings 6 and 7 from being damaged. And can drive safely for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric turbomachine (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. 5 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 disposed on the upper and lower parts 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 is bored, and a hollow centrifugal pump part 61 is formed at the lower part. The centrifugal pump part 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 near bearings 56 and 57 to 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. The hole 63 by centrifugal force,
64 is discharged to the vicinity of the bearings 56 and 57,
Lubricate 57. The lubricating oil that has lubricated the bearings 56 and 57 returns to the oil reservoir 60 through the oil return paths 58 and 59 due to gravity. The lubricating oil exists in a spray state and a droplet 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 unit 70, the space 69 of the motor drive unit is connected to a vacuum pump (not shown) through a pipe via a hole 66 so as to maintain a low pressure with respect to the gas compression unit 70. ing.

The motor 54 has a variable frequency inverter 6.
5, an inductive motor commonly used has an efficiency of 80 to 90% and an input power of about 1%.
0 to 20% is lost and generates heat. About 2/3 of the loss is the stator 54A, and the remaining about 1/3 is the rotor 54A.
B generates heat. The heat generated by the stator 54A is
Heat is dissipated to 7. Motor 5 by natural heat radiation of housing 67
If there is a possibility that the temperature of 4 will be higher than the safe operation range, a flow path for circulating cooling water (not shown) may be provided in the vicinity of the fixed position of the stator 54A of the housing 67 for cooling. On the other hand, the heat generated by the rotor 54B is transferred from the shaft 53 to the gas flowing through the impeller 52 to the housing 6 through the bearings 56 and 57 from the shaft 53.
Radiation from the surface of the rotating body to the housing 67 and the like is radiated to the housing 7, but the impedance of these heat transfer paths is high and sufficient heat cannot be transferred, so that the temperature of the motor rotor 54B increases. In general, the most commonly used squirrel-cage induction motor rotor uses aluminum as the conductor, and a squirrel-cage secondary winding is formed by casting it into the groove of the iron core. If the heat radiating means of the rotor 54B is not provided, a temperature rise exceeding this temperature occurs and the rotor 54B is broken. Therefore, the rotor is cooled by the lubricating oil in a path in which the lubricating oil lubricating the bearing 56 returns to the oil.

[0006]

The conventional electric turbo blower is constructed as described above. However, the bearing which supports the rotating body rotating at high speed generates heat due to the frictional loss of the rolling element and becomes high temperature. For this reason, the lubricating oil is provided for cooling as well as lubrication of the bearing. Although the temperature of the lubricating oil is low at the beginning of the operation of the electric turbo blower and has a cooling effect, the lubricating oil that has cooled and lubricated the upper bearing cools the stator and rotor of the motor, which has been heated and becomes hot, to reduce the oil. The temperature of the lubricating oil rises while returning, and the temperature of the lubricating oil increases with time due to circulation, and eventually does not contribute to cooling of the bearing. Due to such a rise in the temperature of the lubricating oil, the lubrication and cooling of the bearing are significantly deteriorated, so that the temperature of the bearing rises, shortening the life of the bearing and eventually leading to breakage. The present invention has been made in view of such circumstances, and an electric motor that cools a bearing by installing means for cooling an outer ring of a bearing near a bearing of a housing is provided to prevent the bearing from being damaged. It is intended to provide a turbo machine. Further, the present invention provides an electric turbo machine in which a means for cooling lubricating oil for oil is provided, and lubrication and cooling of a bearing can be performed by lowering a lubricating oil temperature to enable long-time safe operation. With the goal.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an electric turbomachine according to the present invention comprises a rotating body comprising a drive shaft on which a motor rotor and a turbine wheel are axially mounted, and a shaft supporting the rotating body. A pair of upper and lower bearings, a housing for mounting the bearings, a pump for supplying lubricating oil for lubricating the bearings, and a lubricating oil flow path are provided in the drive shaft, and a shaft end of the drive shaft is lubricated in the housing. Oil is immersed, and the drive shaft rotates, so that the lubricating oil rises in the drive shaft by the pump, and lubricating oil is supplied from a hole formed in a bearing portion of the drive shaft. In the electric turbomachine, a flow path for circulating cooling water is provided in proximity to a portion of the housing where a bearing that supports the rotating body is attached, so that an outer ring of the bearing can be cooled. Features. Furthermore, in order to solve the above-mentioned problems, the electric turbo machine according to the present invention is characterized in that a cooling water passage for circulating cooling water for the lubricating oil is provided inside so as to be able to cool the lubricating oil.

[0008]

FIG. 1 is a block diagram showing an embodiment of an electric turbo machine provided by the present invention. Turbo blower 1
Are a rotating body composed of an impeller 2 and a motor rotor 4B that are axially mounted on a shaft 3, bearings 6 and 7 that support the rotating body, a housing 17 that holds the bearings at upper and lower portions, and a shaft 3. A hollow shaft hole 12 concentrically drilled, a hollow centrifugal pump portion 11 immersed in oil 10 provided below the shaft hole, and a shaft 3 provided near the bearings 6 and 7 and communicating with the hollow shaft hole 12 are bored. Holes 13, 1
4, a lubrication system including oil return passages 8, 9, which are passages for returning the oil lubricating the bearings to the oil for storing the lubricating oil 10, and provided between the lubrication system and the gas compression unit 20. The cooling system includes a sealing portion 18, cooling water passages 23 and 24 provided in the housing 17, and a cooling source (not shown) connected to each cooling water passage.

Next, the operation of the turbo blower 1 according to the present invention will be described with reference to FIGS. The rotating body rotates at high speed when the motor 4 is excited by the variable frequency inverter 15, and drives the impeller 2 to rotate. The gas sucked from the suction port Pin of the housing 17 by the rotation of the impeller 2 is compressed and discharged from the outlet Pout leading to the gas compression unit 20.

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 shaft 3 is provided in the lower part of the shaft 3 by a centrifugal pump 11.
Pumped along the inner wall of No. 2. The pumped lubricating oil is centrifugally generated by the rotation of the shaft 3 so that the hole 1
3 and 14 are discharged to the vicinity 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 due to gravity through the oil return paths 8 and 9. This lubricating oil exists in a spray state and a droplet state in the space 19 of the motor drive unit. Leakage of the lubricating oil to 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, a vacuum pump (not shown) is connected to the space 16 of the motor drive section through a line so as to maintain a low pressure with respect to the gas compression section 20. It is connected.

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. 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 these heat transfer paths is high and sufficient heat cannot be transmitted, so that the temperature of the motor rotor 4B rises. Therefore, the motor 4 is cooled by the lubricating oil in a path in which the lubricating oil that has lubricated the bearing 6 returns to the oil 10. The temperature of the lubricating oil that has lubricated and cooled the bearing 6 rises with time by cooling the stator 4A and the rotor 4B, which have been heated to high temperatures, and circulating back to the oil sump 10. The lubricating performance is degraded due to the temperature rise of the lubricating oil, the friction between the inner ring and the outer ring of the bearing and the rolling element that rolls at a high speed increases, and the friction loss increases, so that the temperature further rises and eventually breaks. As described above, when the temperature of the lubricating oil rises, the lubricating performance deteriorates and the cooling effect cannot be expected, so that the life of the bearing is remarkably shortened.

For this purpose, according to the present invention, cooling water channels 23 and 24 are provided near the bearings 6 and 7 in the housing 17 to introduce cooling water. Heat is exchanged between the introduced cooling water and a portion where the outer ring of the bearing of the housing 17 circumscribes, the housing is cooled, and the outer rings of the bearings 6 and 7 are cooled to a temperature at which they can be safely operated for a long time. Examples of supplying cooling water to the cooling water passages 23 and 24 are shown in FIGS. In FIG. 2, the cooling water is a heat sink 26 capable of maintaining a sufficient cooling capacity,
For example, it is supplied from a tap water source. In FIG. 3, a heat sink 26 (for example, tap water) forms a circulation channel through a heat exchanger 29 to cool the heat transfer medium circulated by a pump 28, and the circulating heat transfer medium is introduced into the cooling channels 23 and 24. Then, the portion of the housing 17 to which the bearings 6 and 7 are attached is cooled. By effectively cooling the outer races of the bearings 6 and 7 in this manner, the temperature of the high-speed rotating bearing is reduced, and a long-time safe operation is realized.

FIG. 4 shows another embodiment for the same purpose as described above. A means for cooling lubricating oil is provided in place of the cooling system for cooling the bearings 6 and 7, and lubrication and cooling of the bearing and cooling of the rotor 4B of the motor to cool the lubricating oil that has risen. That is, the lubricating oil and the cooling water exchange heat by providing a cooling water passage 25 for circulating the cooling water in the oil 10 of the housing 17 and introducing the cooling water in the configuration shown in FIG. 2 or FIG. Then, the lubricating oil is cooled. By circulating the cooled lubricating oil as described above, the temperature can be lowered to a temperature at which the bearings 6, 7 and the motor 4 can safely operate for a long time, and a long-time safe operation can be realized. Cooling channel 2 shown in FIG.
The holes 3 and 24 may be perforated in the housing 17 or a pipe may be provided in the housing. Cooling water channel 2 shown in FIG.
5 may be provided on the side or bottom of the oil 10 of the housing 17 or on the side and bottom. Further, the cooling water passages 23 and 24 for the bearing and the cooling water passage 25 for cooling the lubricating oil may be provided in parallel.

[0014]

The electric turbo machine according to the present invention is constructed as described above, and has a flow passage for circulating cooling water in the vicinity of a portion where a bearing for supporting a rotating body of a housing is mounted. In order to cool the outer ring of the bearing, lower the temperature of the bearing which rotates at a high speed, or provide a cooling water passage through which cooling water flows for lubricating oil, and heat exchange between the lubricating oil and the cooling water reduces the lubricating oil temperature. By lowering the lubrication and cooling of the bearing and the cooling of the motor, the bearing can be used continuously for a long time, and the high-speed rotating electric turbomachine can be operated for a long time in a safe temperature range. .

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a configuration of a cooling water supply example of the electric turbomachine according to the present invention.

FIG. 3 is a diagram showing a configuration of another example of cooling water supply of the electric turbo machine according to the present invention.

FIG. 4 is a diagram showing a configuration of another embodiment of the electric turbo machine according to the present invention.

FIG. 5 is a diagram showing a configuration of a conventional electric turbomachine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Turbo blower 2 ... Impeller 3 ... Shaft 4 ... Motor 4A ... Stator 4B ... Rotor 6, 7, ... Bearing 8, 9 ····· Oil return path 10 ···· For oil 11 ····· Centrifugal pump part 12 ··· Shaft hollow hole 13, 14, 1
6 Hole 15 Inverter 17 Housing 18 Seal part 19 Space for motor drive part 20 Gas compressing parts 23, 24, 2
5. Cooling water channel 26 Heat sink 27 Drainage channel Pump 29 Heat exchanger Pin Inlet Inlet Pout Outlet

Claims (2)

[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 housing carrying the bearing, and lubrication for lubricating the bearing. A pump for supplying oil and a lubricating oil flow path are provided in the drive shaft, and a shaft end of the drive shaft is immersed for lubricating oil in the housing. An electric turbomachine that rises inside the drive shaft and is configured to supply lubricating oil from a hole drilled in a bearing portion of the drive shaft,
An electric motor characterized in that a flow passage through which cooling water flows is provided in proximity to a portion of the housing where an upper bearing for supporting the rotating body is mounted, so that an outer ring of the bearing can be cooled. Turbo machinery. 2. 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 housing carrying the bearings, and lubricating the bearings. A pump for supplying oil and a lubricating oil flow path are provided in the drive shaft, and a shaft end of the drive shaft is immersed for lubricating oil in the housing. An electric turbomachine that rises inside the drive shaft and is configured to supply lubricating oil from a hole drilled in a bearing portion of the drive shaft,
An electric turbomachine, wherein a pipe for flowing cooling water for the lubricating oil is provided therein so that the lubricating oil can be cooled.