JP3594809B2 - underwater pump - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a submersible pump that pumps water by rotating an impeller with an electric motor.
[0002]
[Prior art]
Conventionally, as a submersible pump, as shown in FIG. 2, a vertical cylindrical housing 3 installed in a pumping channel 2 on the inner periphery of a column 1, and an electric motor 5 housed in a motor housing 4 of the housing 3, It has a series of rotating shafts 7 fixed to the rotor 6 of the electric motor 5, and an impeller 8 attached to the tip (lower end) of the rotating shaft 7, and pumps water sucked by the rotation of the impeller 8. 2 is known which is configured to discharge water after being pumped.
[0003]
In the conventional submersible pump, a series of rotating shafts 7 are rotatably supported in a housing 3 by grease-lubricated bearings 9 and 10 arranged above and below a rotor 6 of an electric motor 5. Therefore, the radial load generated by the rotation of the rotor 6 is supported by the upper and lower bearings 9 and 10, and the weight of the rotating parts such as the rotor 6, the rotating shaft 7 and the impeller 8 and the thrust load generated by the rotation of the impeller 8 are lower. Of the bearing 10.
[0004]
[Problems to be solved by the invention]
However, when the size of the pump is increased and the output of the electric motor 5 is increased, the amount of heat generated by the electric motor 5 is significantly increased, and the heat storage of the bearings 9 and 10 is increased due to heat conduction, and the temperature of the bearings 9 and 10 is increased. Even if the bearings 9 and 10 become hot, the upper bearing 9 only supports the main shaft 7 under light load and high temperature conditions in which the radial load generated by the rotation of the rotor 6 is applied. We can respond enough. However, the lower bearing 10 is subjected to a severe load in which a radial load generated by the rotation of the rotor 6, a weight of rotating parts such as the rotor 6, the rotating shaft 7, the impeller 8, and a thrust load generated by the rotation of the impeller 8 are applied. Since the rotating shaft 7 must be supported under high load and high temperature conditions, there is a possibility that seizure or burning may occur in the case of a grease lubrication type, which limits the production of a large submersible pump.
[0005]
For this reason, in the case of a large-sized submersible pump having a large output, the bearing 10 is lubricated by an oil bath lubrication system having better lubrication conditions than the grease lubrication system, and the lubricating oil is provided with a function as a heat absorbing medium. It is conceivable that the heat storage is suppressed by actively cooling 10. However, the dry electric motor (dry motor) 5 has an air layer around the rotor 6 and the stator 6A and has essentially the same structure as a land motor. In the structure of lubricating by the bath lubrication system, it is necessary to take a sealing measure for preventing lubricating oil from entering the motor housing 4. For this reason, the oil seal structure becomes considerably complicated, making it difficult to manufacture and assemble. In addition, there are drawbacks in that the initial cost of the large submersible pump becomes unnecessarily high.
[0006]
Therefore, the present invention reliably prevents seizure and burnout due to high temperature of the bearing by lubricating the bearing under a high load and high temperature condition with a simple structure during operation of a large submersible pump. It is an object of the present invention to provide a submersible pump capable of producing a limited large specification.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a submersible pump according to the present invention includes a housing installed in a pumping passage, an electric motor housed in a motor housing of the housing, a rotating shaft fixed to a rotor of the electric motor, An impeller fixed to the tip end of the rotating shaft outside the housing, wherein the submersible pump pumps up and discharges water sucked by the rotation of the impeller to the pumping passage, wherein the rotating shaft is provided with the electric motor. A coupling that is divided into two shafts, a rotation output shaft fixed to the rotor and a pump shaft to which the impeller is fixed, and that connects these two shafts simultaneously so as to be able to rotate simultaneously outside the housing; A motor-side bearing rotatably supporting both ends of the shaft; and a rotatably supporting the coupling side and the impeller side of the pump shaft outside the housing. And a pump-side bearing of, is characterized in that the lubricating oil tank is provided with the coupling and the pump side bearing for an oil bath lubrication.
[0008]
According to the present invention, since the rotating shaft is divided into two shafts, the rotating output shaft fixed to the rotor of the electric motor and the pump shaft fixed to the impeller, the rotating output shaft supporting light load and high temperature is supported. The motor-side bearing and the pump-side bearing which must support the pump shaft to which a high load and high temperature condition is loaded can be arranged so as to share roles. Therefore, use a grease lubricated bearing for the motor side bearing, use an oil bath lubricated pump side bearing for the pump shaft side with better lubrication conditions than the grease lubricated type, and use lubricating oil for the lubricating oil tank. By having a function as a heat removal medium, it is possible to actively cool and suppress heat storage.
[0009]
In addition, since the lubricating oil tank for lubricating the coupling and the bearing on the pump side is provided outside the housing, it is possible to reliably prevent lubricating oil from entering the motor housing without taking measures to seal the complicated structure. can do.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to the drawings. The same or corresponding parts as those of the conventional example described with reference to FIG. FIG. 1 is a longitudinal sectional view of a submersible pump according to the present invention. In this figure, the submersible pump includes a vertical cylindrical housing 3 installed in a pumping passage 2 on the inner periphery of a column 1, and an electric motor 5 housed in a motor housing 4 of the housing 3. 7 is divided into two shafts: a motor shaft (rotation output shaft) 11 fixed to the rotor 6 of the electric motor 5 and a pump shaft 12 having an impeller 8 fixed to the tip outside the housing 3. 11 and 12 are connected to each other via a coupling 13 so as to be able to rotate simultaneously outside the housing 3. The coupling 13 is constituted by a gear coupling or a spline coupling that can absorb slight eccentricity and slight axial movement.
[0011]
On the other hand, both ends of the rotary output shaft 11 are rotatably supported by grease-lubricated motor-side bearings 14 and 15 in the housing 3. That is, the radial load generated by the rotation of the rotor 6 is supported by the motor-side bearings 14 and 15.
[0012]
On the other hand, both parts of the pump shaft 12 on the coupling 13 side and the impeller 8 side are rotatable by oil bath lubrication type pump side bearings 16 and 17 having better lubrication conditions than grease lubrication type outside the housing 3. Supported. That is, the weights of the rotating parts such as the pump shaft 12 and the impeller 8 and the thrust load generated by the rotation of the impeller 8 are supported by the pump-side bearings 16 and 17.
[0013]
Further, a lubricating oil tank 18 for lubricating the coupling 13 and the pump-side bearings 16 and 17 with an oil bath is provided outside the housing 3.
[0014]
In the above configuration, when the electric motor 5 is energized, the rotary output shaft 11, the pump shaft 12, and the impeller 8 rotate simultaneously, and the water sucked by the rotation of the impeller 8 is pumped to the water pumping passage 2 and discharged. In this operating state, the thrust load generated by the weight of the rotor 6 and the rotary output shaft 11 and the radial load generated by the rotation of the rotor 6 are supported by grease-lubricated motor-side bearings 14 and 15, and the pump shaft 12 and the impeller 8 are supported. The thrust load and the radial load generated by the weight of the rotating part and the rotation of the impeller 8 are supported by pump-side bearings 16 and 17 of an oil bath lubrication type.
[0015]
That is, since the rotating shaft 7 is divided into two shafts, the rotating output shaft 11 fixed to the rotor 6 of the electric motor 5 and the pump shaft 12 fixed to the impeller 8, the rotating output shaft to which a light load and a high temperature are loaded. The motor-side bearings 14 and 15 that support the pump 11 and the pump-side bearings 16 and 17 that must support the pump shaft 12 that is loaded under high load and high temperature conditions can be arranged in a shared role. Therefore, grease-lubricated bearings are used for the motor-side bearings 14 and 15, and oil-bath lubricated pump-side bearings 16 and 17 are used for the pump shaft 12 with better lubrication conditions than the grease-lubricated type, and By providing the lubricating oil 18A of the lubricating oil tank 18 with a function as a heat transfer medium, the pump-side bearings 16 and 17 can be actively cooled to suppress heat storage and lubricate the coupling 13 with an oil bath.
[0016]
Therefore, even if the size of the pump is increased and the output of the electric motor 5 is increased, the heat generation of the electric motor 5 is remarkably increased. Since the seizure and burnout of the side bearings 16 and 17 can be reliably prevented, it is possible to manufacture a large-sized submersible pump which has been limited in the past.
[0017]
In addition, since the lubricating oil tank 18 for oil-lubricating the coupling 13 and the pump-side bearings 16 and 17 is provided outside the housing 3, the lubricating oil tank 18 can be inserted into the motor housing 4 without taking measures for oil sealing of a complicated structure. Therefore, the intrusion of the lubricating oil can be reliably prevented, so that the structure is prevented from being complicated, the production and the assembly are facilitated, and the cost of the large submersible pump can be reduced.
[0018]
【The invention's effect】
The present invention uses a grease-lubricated bearing for the motor-side bearing that supports the rotary output shaft loaded with light load and high temperature, and uses a grease-lubricated bearing for the pump-side bearing loaded under high load and high temperature conditions. Using lubricating oil-bath bearings with excellent lubrication conditions, the lubricating oil in the lubricating oil tank has a function as a heat transfer medium. Because the pump can be lubricated, the pump becomes larger and the output of the motor increases, so even if the heat generated by the motor increases significantly, the pump-side bearings are actively cooled to suppress heat storage, and the pump is heated to a higher temperature. Since seizure and burnout of the side bearings can be reliably prevented, it is possible to manufacture a large-sized submersible pump which has been limited in the past. In addition, since the lubricating oil tank that lubricates the coupling and pump-side bearings in an oil bath is provided outside the housing, it is possible to ensure that the lubricating oil enters the motor housing without taking measures for oil sealing of complicated structures. Since this can be prevented, the structure is prevented from being complicated, the manufacturing and assembly are facilitated, and the cost of the large submersible pump can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a conventional example.
[Explanation of symbols]
2 Pumping path 3 Housing 4 Motor housing 5 Motor 6 Rotor 7 Rotary shaft 8 Impeller 11 Rotary output shaft 12 Pump shaft 13 Coupling 14 Motor side bearing 15 Motor side bearing 16 Pump side bearing 17 Pump side bearing 18 Lubricating oil tank 18A Lubrication oil

Claims (1)

A housing installed in the pumping passage, a motor housed in a motor housing of the housing, a rotating shaft fixed to a rotor of the motor, and an impeller fixed to a tip side of the rotating shaft outside the housing. A submersible pump that pumps water sucked by the rotation of the impeller into the pumping path and discharges the water, wherein a rotary output shaft having the rotary shaft fixed to the rotor of the electric motor, and a pump shaft having the impeller fixed to the rotor And a coupling that connects the two shafts together so that they can rotate simultaneously outside the housing, and a motor-side bearing that rotatably supports both end portions of the rotary output shaft. A pump-side bearing that rotatably supports the coupling side and the impeller side of the pump shaft outside the housing, respectively. Water pump, wherein a lubricating oil tank of the flop-side bearing to an oil bath lubrication is provided.

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