JPH08312576A - underwater pump - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain a submersible pump which is easy to control the flow rate while increasing the external shape and has a large starting torque and is excellent in handleability. [Construction] The outer rotation type DC brushless motor 1 is vertically installed in a motor protection case 19, a motor control circuit section 16 and a DC power conversion circuit section 17 are installed above the motor protection case 19, and the pump protection case 19 is provided with circuit protection. The cover 20 was joined to house the motor and the circuit section in a watertight space. The outer rotation type DC brushless motor 1 is a submersible pump that rotates at a predetermined speed regardless of the frequency of the AC power source to facilitate discharge amount control and has a large starting torque.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submersible pump, and more particularly to a vertical submersible pump suitable for use in wastewater treatment.

[0002]

2. Description of the Related Art General vertical submersible pumps are
As shown in Japanese Patent No. 14591, an induction motor is used which is powered by single-phase and three-phase AC power sources. In such a submersible pump using an induction motor, it is unavoidable that the number of revolutions (speed) changes due to the difference in the frequency of the AC power source, and it is necessary to use a pump runner with a shape corresponding to the power source frequency. In addition, there is a problem that the fluctuation of the pump flow rate (discharge amount) becomes large because the rotation speed of the motor fluctuates with respect to the load fluctuation due to the change of the head.

On the other hand, the maximum number of revolutions of the induction motor is determined by the number of poles and therefore cannot be set to an arbitrary number of revolutions. Therefore, it is very difficult to control the flow rate by controlling the number of revolutions.

Further, since the induction motor has a smaller starting torque than the DC motor, it is difficult to discharge the foreign matter when the motor is restarted after foreign matter or the like is caught in the pump runner and the protection circuit is activated and stopped. There are drawbacks.

[0005]

There is an inverter control device as a control device for controlling the rotation speed of the induction motor to an arbitrary value without being influenced by the frequency of the AC power supply. The inverter control device uses an AC power supply as a DC power supply. Since a conversion circuit for converting into the water and an inverter for supplying power to the induction motor from this DC power source are required, the external shape of the submersible pump becomes large.
Moreover, it is difficult to increase the starting torque.

The present invention has been made in order to solve such a problem, and facilitates flow rate control while suppressing an increase in the external shape, and increases the motor starting torque to provide excellent handleability. The purpose is to provide a submersible pump.

[0007]

The present invention uses an abduction type DC brushless motor to drive a pump runner, and performs power supply phase switching and rotation speed control with a power supply circuit section for generating DC power from an AC power supply. A motor control circuit unit for performing the operation is arranged above the outer rotor type DC brushless motor, and is housed in a watertight state in a motor protection case and a circuit protection cover.

[0008]

The DC brushless motor has a higher efficiency than the induction motor. Especially, in the outer rotor type DC brushless motor, since the stator winding can be wound directly from the outer circumference of the stator iron core, the dimension in the height direction can be reduced. It can be made small, and a large torque is easily generated.

Further, the miniaturized outer rotation type DC brushless motor forms a space above which a power supply circuit section and a motor control circuit section are installed.

[0010]

An embodiment of the present invention will be described with reference to the drawings.

First, the structure of the outer rotor type DC brushless motor will be described with reference to FIGS. The stator portion 2 of the outer rotation type DC brushless motor 1 is configured by directly winding a stator winding 4 by a winding machine through an electric insulator in a slot formed on the outer circumference of the stator iron core 3. Further, it is fixed to the motor frame 11 by adhesion. In this way, the winding method in which the stator winding 4 is directly wound around the stator iron core 3 from the outer periphery can reduce the height dimension of the stator winding 4 protruding at both ends of the stator iron core 3. As a result, the height dimension of the outer rotation type brushless motor 1 can be suppressed.

The rotor portion 5 has a main magnet 7 and an FG for forming a magnetic field as a motor in the rotor yoke 6.
An FG magnet 8 forming a magnetic field as a sensor is adhered and fixed by an adhesive or the like, and a motor rotating shaft 9 is press-fitted into the rotor yoke 6 to be fastened, and a ball bearing 10a,
It is rotatably supported by the motor frame 11 by 10b.

The motor frame 11 is a structural member such as an aluminum die casting in consideration of mechanical strength and heat dissipation of the stator winding 4.

Next, the rotation position detecting means by the hall element for switching the phase of the power supply to the stator winding 4 according to the rotation position of the magnetic pole of the main magnet 7 in the outer rotor type brushless motor 1, and the rotation position detecting means. An FG sensor for detecting the rotation speed for controlling the speed will be described.

The FG coil pattern 1 is formed on the motor circuit board 12 made of a composite material such as copper foil and paper phenolic resin.
2a, a lead pattern 12b soldered to the lead-out portion of the stator winding 4, and a lead pattern 12c soldered to the Hall elements 13a to 13c are formed of copper foil, and the motor cable 14 is connected to these. To be done. The motor circuit board 12 is fixed to the motor frame 11 with fixing screws 43. In the state where the stator portion 2 and the rotor portion 5 are combined, the FG coil pattern 12a
Faces the FG magnet 8 through a minute gap so that the magnetic field of the FG magnet 8 of the rotor section 5 acts, and the magnetic field of the FG magnet 8 rotates when the rotor section 5 rotates, so that the rotation speed is increased. According to the FG coil pattern 12
The voltage induced in a is output as a rotation speed signal. The Hall elements 13a to 13c face the main magnet 7 through a minute gap so that the magnetic field of the main magnet 7 of the rotor unit 5 acts, and the magnetic pole position detection is performed when the magnetic poles of the main magnet 7 face each other. A signal is generated, and rotation torque is generated by controlling the switching of the feeding phase of the stator winding 4 based on the magnetic pole position detection signal.

Next, a circuit configuration for generating a DC power source from an AC power source and switching the feeding phase of the drive current flowing through the stator winding 4 of the outer rotor type brushless motor 1 and controlling the rotation speed will be described with reference to FIGS. And FIG. 3 will be described.

This circuit configuration basically has a transistor for feeding phase switching control of the stator winding 4, a motor control circuit section 16 for performing rotation speed control and overload protection, and an AC power source converted to a DC power source. And a DC power supply conversion circuit section 17 for controlling the power supply cable 22 and the float switch cable 24.
And the motor cable 1 in the submersible pump.
4 to the motor circuit board 12.

The DC power conversion circuit unit 17 is a power circuit board 4
4, the motor control circuit unit 16 is mounted on the control circuit board 4
Implemented in 5. Power supply phase switching control transistor (motor driver) 46 in the motor control circuit unit 16
Is attached to the aluminum heat sink 18 for heat dissipation and connected to the control circuit board 45. Control circuit board 4
5 and the power supply circuit board 44 are placed on the aluminum radiator plate 18, and the motor control circuit unit 16 and the DC power supply conversion circuit unit 17 are mounted.
In order to position and install the above-mentioned outer type DC brushless motor 1 in two stages, the aluminum heat dissipation plate 18 is
As will be described later, the fixing screw 4 is attached to the motor protection case 19.
Fix by 9. The motor control circuit unit 16 and D
A part of the C power supply conversion circuit unit 17 can be mounted on a common circuit board.

In the submersible pump, weight reduction and watertightness (airtightness) as well as improvement of pump performance are important in the structure of the product. The outer DC brushless motor 1, the DC power conversion circuit unit 17 and the motor control circuit unit 16 are formed by a motor protection case 19 and a circuit protection cover 20 in order to reduce the number of joints of parts related to watertightness as much as possible. The motor protection case 19 and the circuit protection cover 20 are to be housed in a space, and formed by molding a synthetic resin that can withstand various water qualities.

Details of the motor protection case 19 are shown in FIGS.
Will be described with reference to. The motor protection case 19 is provided with a centering protrusion 19a for fixing the motor frame 11 and a fixing screw for positioning the motor frame 11 in order to fix the outer rotation type DC brushless motor 1 in a fixed position and install it vertically. A plurality of motor fixing screw holes 19b for fixing 11 are provided. Further, as described above, the plurality of heat radiation plate fixing screw holes 19c for fixing the aluminum heat radiation plate 18 and installing the circuit portion are provided.

Further, as will be described later, the motor protection case 19 is provided with a rubber ring 21 for retaining a watertightness for securing watertightness of the joint surface when the circuit protection cover 20 is butted and screwed and coupled. Ring mounting groove 19
d.

Next, the circuit protection cover 20 is shown in FIG.
0, with reference to FIG. This circuit protection cover 2
As shown in FIG. 1, by combining the motor protection case 19 with a case coupling bolt 37 and a case coupling nut 38 and tightening them, the water-tight rubber ring 21 assists the motor protection case 19 and the motor protection case 19. It is bound in a watertight state. The circuit protection cover 20 includes a handle 20a for carrying and installing the submersible pump,
A column screw hole 20b for mounting the column 26 for the float switch, a power cable 22 for the DC power conversion circuit unit 17 to receive an external AC power source, and a motor control circuit unit 16 for detecting the water level from the float switches 28a, 28b. A cable through hole 20 for penetrating the circuit protection cover 20 and pulling it out to the outside while maintaining a watertightness of the float switch cable 24 for inputting a signal.
c, 20d.

The detailed structure of the cable outlet portion will be described with reference to FIG. The power cable 22 and the float switch cable 24, which penetrate through the circuit protection cover 20, have penetrating rings 23 and 25 formed integrally with the power cable 22 and the float switch cable 24, respectively, which are made of a rubber material. Rings 23 for each output,
25 is inserted into the through holes 20c, 20d of the circuit protection cover 20, the collars 23a, 25a are brought into contact with the outer surface of the circuit protection cover 20, and the metal sealing caps 27a, 27b are brought into contact with the outsides thereof, respectively. The flanges 23a, 2 are tightened with fixing screws 39a, 39b screwed into the lead-out set screw holes 20e, 20f provided in the lead-out portion of the circuit protection cover 20.
The water-tight state is obtained by bringing 5a into close contact with the elasticity of rubber.

As shown in FIG. 1, the intermediate casing 30 is connected to the bottom of the motor protection case 19 by a fixing screw 40 so as to penetrate the motor rotating shaft 9 with a mechanical seal 29 interposed therebetween. The mechanical seal protective oil chamber 4 is hermetically sealed around the mechanical seal 29 by forming a watertight structure by the ring 35.
Form 2

The pump portion is a vortex type pump, and the pump runner 34 is fixed to the shaft end of the motor rotating shaft 9 penetrating the intermediate casing 30 by a fixing screw 36. The pump upper casing 31 and the pump lower casing 32 are coupled to the lower side of the intermediate casing 30 by casing coupling screws 47 and 48, and the pump runner 3 is connected.
A pump chamber for housing 1 is formed. The pump lower casing 32 is formed with a suction hole 32a, and the pump upper casing 32 is provided with a flange 33 having a female screw portion for pipe connection. It should be noted that the components constituting these are also formed by molding the same synthetic resin as that of the motor protection case 19 and the circuit protection cover 20.

A comparative example of the motor characteristics of the outer rotor type DC brushless motor 1 in the submersible pump according to the present invention thus constructed and the induction motor in the conventional submersible pump is shown in FIG.
It is shown in FIG. The characteristic of the outer rotor type DC brushless motor 1 is that the torque and the rotational speed change linearly when the rotational speed is not controlled (state in which the rotational speed is not controlled), and when the rotational speed is 0, that is, at the time of startup, the maximum torque is obtained. Becomes Also, unlike the induction motor, the maximum rotation speed can be set arbitrarily by changing the magnetic flux of the magnet and the coil winding specifications, and
A desired rotation speed can be obtained without being influenced by the frequency of the AC power supply. Further, it is possible to improve the starting performance by increasing the torque at the time of starting.

This submersible pump is placed (installed) in water to be drained by connecting a drain pipe to the flange 33. The DC power conversion circuit unit 17 converts the AC power received through the power cable 22 into a DC power. Then, the motor control circuit unit 16 uses this DC power source to refer to the water level detection signals from the water level detection float switches 28a and 28b to turn on / off the power supply to the outer rotation type DC brushless motor 1 (operation and operation). Stop) and drain.

If the rotation speed control signal is executed using the rotation speed detection signal from the FG sensor, the rotation speed can be controlled to a constant speed with respect to a change in the load torque within a certain range. This makes it possible to reduce the amount of change in the pump discharge flow rate by keeping the number of revolutions constant with respect to changes in the load such as the pump head. If feedback control is performed so that the discharge flow rate is constant, a constant discharge amount can be continuously obtained regardless of the height of the lift.

Further, by providing the motor control circuit section 16 with a protection circuit such as a current limiter, it is possible to perform safety protection control such as stopping the motor at the time of overload.

Further, such a submersible pump may be a submersible pump corresponding to a DC power source which uses a battery power source of an automobile or the like by omitting the DC power source conversion circuit section 17.

[0031]

As described above, in the submersible pump of the present invention, by using the outer rotation type DC brushless motor as the drive motor, the size can be reduced in the height direction. The downsized DC brushless motor allows the DC power conversion circuit section and the motor control circuit section to be installed in the space obtained above the outer DC brushless motor. It is possible to obtain a submersible pump that is easy to handle while suppressing the flow rate while increasing the starting torque and having excellent handleability.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a submersible pump according to the present invention.

FIG. 2 is a partial sectional view detailing a cable outlet portion of the submersible pump according to the present invention.

FIG. 3 is an electric block of the submersible pump according to the present invention.

FIG. 4 is a vertical sectional side view of an outer rotation type DC brushless motor in the submersible pump according to the present invention.

5 is a bottom view of the outer rotor type DC brushless motor shown in FIG. 4. FIG.

6 is a plan view of a motor circuit board in the outer rotation type DC brushless motor shown in FIG.

7 is a side view of the motor circuit board shown in FIG.

FIG. 8 is a plan view of a motor protection case in the submersible pump according to the present invention.

9 is a vertical side view of the motor protection case shown in FIG.

FIG. 10 is a plan view of a circuit protection cover in the submersible pump according to the present invention.

11 is a vertical side view of the circuit protection cover shown in FIG.

FIG. 12 is an abduction type D used in the submersible pump according to the present invention.
It is a characteristic comparison figure of a C brushless motor and the motor used for the conventional submersible pump.

[Explanation of symbols]

 1 Outer rotor type DC brushless motor 2 Stator part 3 Stator iron core 4 Stator winding 5 Rotor part 6 Rotor yoke 7 Main magnet 8 FG magnet 9 Motor rotating shaft 11 Motor frame 12 Motor circuit board 12a FG coil pattern 13a- 13c Hall element 16 Motor control circuit section 17 DC power conversion circuit section 18 Aluminum heat sink 19 Motor protection case 20 Circuit protection cover 22 Power cable 23, 25 Lead-out ring 24 Float switch cable 26 Float switch column 28a, 28b Float switch 30 Intermediate casing 31 Pump upper casing 32 Pump lower casing 34 Pump runner

Claims (7)

[Claims] 1. An outer rotation type DC brushless motor having a built-in speed detecting means, a motor protection case having the outer rotation type DC brushless motor installed vertically so as to project a rotary shaft thereunder, and the outer rotation type DC brushless motor. A circuit board installed above the DC brushless motor and mounting a motor control circuit and a power supply circuit, and a space in which the abduction type DC brushless motor and the circuit board are installed by being screwed to the motor protection case. A submersible pump comprising: a circuit protection cover that closes the water-tight state; and a pump section that includes a pump runner that is attached to a rotating shaft that projects downward from the motor protection case. 2. The submersible pump according to claim 1, wherein the motor control circuit and the power supply circuit are mounted on separate circuit boards and are installed in two stages above the outer rotation type DC brushless motor. . 3. The circuit board according to claim 1, wherein the motor control circuit has a phase switching control transistor mounted on an aluminum radiator plate for switching a feeding phase to a stator winding of the outer rotor type DC brushless motor. A submersible pump characterized by being electrically connected to. 4. A submersible pump according to claim 1, wherein the motor protection case and the circuit protection cover are molded of synthetic resin. 5. An outer rotation type DC brushless motor having a built-in speed detecting means, a motor protection case in which the outer rotation type DC brushless motor is vertically installed, and a rotary shaft is projected below the outer rotation type DC brushless motor; A circuit board installed above the DC brushless motor and mounting a motor control circuit, and a space in which the abduction DC brushless motor and the circuit board are installed by being screwed and coupled to the motor protection case are watertight. A submersible pump comprising: a circuit protection cover that is closed to the inside; and a pump section that includes a pump runner that is attached to a rotating shaft that projects downward from the motor protection case. 6. The circuit board according to claim 5, wherein the motor control circuit mounts a phase switching control transistor for switching a power supply phase to a stator winding of the outer rotor type DC brushless motor on an aluminum radiator plate. A submersible pump characterized by being electrically connected to. 7. The submersible pump according to claim 1, wherein the motor control circuit controls the operation and stop of the outer rotation type DC brushless motor based on an on / off signal of a float switch.