JP2005030322A - Pump, and dishwasher using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump capable of eliminating foreign matters even when foreign matters enter the pump and a motor is locked. <P>SOLUTION: A pump chamber 14 is provided below a pump 10 comprising a brushless DC motor, a rotor 18 is disposed inside a ring-shaped stator 16, and an impeller 44 is integrated with the rotor 18. When foreign matters enter the pump 10, and a motor 12 is stopped, foreign matters are removed by turning the impeller 44 in the reverse direction, or alternately repeating the reverse rotation and the normal rotation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pump.

  Conventionally, various pumps have been proposed (Patent Document 1).

  In such a pump, foreign matter enters the pump during operation, and the foreign matter is caught between the impeller and the wall of the pump chamber, and the rotation of the motor that rotates the pump is locked and stops. There is a problem.

When such foreign matter enters and the rotation of the motor stops, it is necessary to disassemble the pump in order to remove the foreign matter. Therefore, extra cost is required for the maintenance of the pump, and there is a problem that the work is troublesome.
JP 10-22915

  Therefore, in view of the above problems, the present invention provides a pump capable of removing foreign matter even when foreign matter enters the pump and the motor is locked, and a dishwasher using the pump. is there.

  The invention of claim 1 has an inner rotor type motor in which a rotor is rotatably disposed in a hollow portion on the inner peripheral side of a ring-shaped stator, and is provided on one side portion in the axial direction of the hollow portion. A pump chamber is disposed, coaxially with the rotor, and an impeller is disposed in the pump chamber; a fluid inflow port is opened on the other side of the hollow portion in the axial direction; When an outflow port opens in the pump chamber located in the radially outward direction and the impeller rotates together with the rotor, the fluid that has flowed into the inflow port passes through the cavity along the axial direction, and the pump In the pump that reaches the chamber and flows out from the outflow port, when the driving means for rotating the motor, the lock detecting means for detecting the locked state of rotation of the rotor, and the lock detecting means detect the locked state, Whether to reverse the impeller Or a pump, characterized in that it comprises a control means for controlling said drive means so as to repeat reversal and forward alternately.

  According to a second aspect of the present invention, a fixed shaft is erected in the axial direction from the pump chamber, the rotor is rotatably arranged with respect to the fixed shaft, the rotor is ring-shaped, and the ring-shaped rotation The pump according to claim 1, wherein fluid flows along the axial direction on the inner peripheral side of the child.

  According to a third aspect of the present invention, the motor is a brushless DC motor, a permanent magnet is disposed on the rotor, and the driving means is a stator winding of each phase wound around the stator core of the stator. 2. The pump according to claim 1, further comprising: an inverter circuit that outputs a drive current to the inverter circuit; and a PWM circuit that outputs a PWM signal to each switching element of the inverter circuit.

  According to a fourth aspect of the present invention, there is provided a dishwasher characterized in that water is sprayed on tableware and the like using the pump according to at least one of the first to third aspects.

  In the pump according to the first and second aspects, when a foreign substance enters the pump and the rotation of the rotor or impeller stops and the locked state is established, the lock detecting means detects the locked state. When this locked state is detected, the control means controls the driving means to reversely rotate the impeller or alternately repeat reverse rotation and forward rotation.

  By rotating the impeller in this way, foreign matters can be destroyed or removed.

  As described above, in the pump of the present invention and the dishwasher using the pump, foreign matter that has entered the pump can be easily removed, so there is no need to disassemble the pump.

  In the pump according to the third aspect, since the motor is a brushless DC motor, the forward rotation and the reverse rotation of the impeller can be easily controlled.

  According to the dishwasher of the fourth aspect, even if foreign matter enters the pump, it is not necessary to disassemble the pump and foreign matter can be easily removed.

(First embodiment)
Hereinafter, a pump 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The pump 10 of the present embodiment is used in a dishwasher, and the water that has flowed out by this pump is sprayed on the dish and the like for cleaning.

(1) Structure of Pump 10 The structure of the pump 10 will be described with reference to FIG.

  The pump 10 includes a motor 12 and a pump chamber 14 attached to the motor 12.

  The motor 12 is a three-phase brushless DC motor, and includes a ring-shaped stator 16 and a rotor 18 disposed in a hollow portion 20 on the inner peripheral side of the ring-shaped stator 16. That is, the motor 12 is an inner rotor type motor.

  In the ring-shaped stator 16, an insulating layer 24 is formed of resin on the ring-shaped stator core 22, and a three-phase stator winding 26 is wound around the stator core 22 through the insulating layer 24. ing.

  The stator 16 is fixed to a first casing 28 made of synthetic resin. The first casing 28 forms a ceiling surface and a side surface of the pump chamber 14, and a cylindrical protruding portion 30 protrudes from a central portion thereof, and an inlet 32 through which water flows into the upper surface of the protruding portion 30. Is open.

  The stator 16 is fitted so as to fit into the cylindrical protrusion 30. That is, the protrusion 30 is inserted into the inner periphery of the ring-shaped stator 16.

  The stator 16 is covered with a cylindrical lid 34 made of synthetic resin and is housed between the lid 34 and the first casing 28.

  The rotor 18 that is rotatably disposed in the cavity 20 on the inner peripheral side of the stator 16, that is, the cavity 20 on the inner peripheral side of the protrusion 30, also has a cylindrical shape, and an upper portion of the cylindrical shape. Are provided with ring-shaped permanent magnets 36 in which S poles and N poles are alternately arranged. A cylindrical rotary shaft 38 is coaxially arranged at the central portion of the cylindrical rotor 18. The rotating shaft 38 and the ring-shaped rotating member 40 that fixes the permanent magnet 36 are connected by an arm member 42.

  An impeller 44 is continuously formed at the lower portion of the rotor 18. The impeller 44 is provided with a plurality of blades 46 at equal intervals.

  The pump chamber 14 has a ceiling portion and side surfaces formed by the first casing 28 described above, and a bottom surface formed by a bottom plate 48. The bottom plate 48 and the first casing 28 are fixed by screws 50.

  In the central portion of the pump chamber 14, a fixed shaft 52 is erected upward from the bottom plate 48. The fixed shaft 52 is covered with a cylindrical rotating shaft 38 of the rotor 18 via a bearing 54 which is a sliding bearing. As a result, the rotor 18 and the impeller 44 are rotatable about the fixed shaft 52. A nut 56 is screwed onto the upper end portion of the fixed shaft 52 to prevent the bearing 54 and the rotor 18 from being detached.

  An outflow port 58 is provided in the outer peripheral portion of the pump chamber 14, that is, in the radially outward direction of the impeller 44, and an outflow path 60 is continuously extended from the outflow port 58.

(2) Motor 12 drive circuit 64
Next, the drive circuit 64 of the motor 12 will be described based on the block diagram of FIG.

  Since the motor 12 is a three-phase brushless DC motor as described above, the drive circuit 64 includes an inverter circuit 66, a PWM circuit 68, a control unit 70, and a lock detection circuit 72. The wiring board having the drive circuit 64 is provided separately from the motor 12.

  Based on the speed command signal S input from the main control unit of the dishwasher, the control unit 70 composed of a microcomputer controls the PWM circuit 68. The PWM circuit 68 determines a duty ratio based on the control signal from the control unit 70, and outputs a PWM signal to each switching element of the inverter circuit based on the duty ratio. In the inverter circuit 66, each switching element is turned on / off based on the PWM signal from the PWM circuit 68, and a drive current is supplied to the three-phase stator winding 26 of the motor 12 to rotate the motor 12.

  The lock detection circuit 72 detects the drive current supplied to the stator winding 26 of each phase, and when the detected drive current rises above a predetermined reference value, the lock detection circuit 72 In response to this, a lock signal R is output.

  The control unit 70 to which the lock signal R has been input performs control for removing foreign matter from the PWM circuit 68. This control method will be described below.

  Accordingly, when the speed command signal S is input from the main control unit of the dishwasher, the control unit 70 controls the PWM circuit 68, the PWM circuit 68 outputs a PWM signal to the inverter circuit 66, and the inverter circuit 66 is the stator winding. A drive current is output to 26, and the rotor 18 of the motor 12 rotates.

(3) Normal Operating State of Pump 10 First, the normal operating state of the motor 12 will be described with reference to FIGS.

  When the rotor 18 and the impeller 44 rotate, water enters from the inlet 32, passes through the cavity 20 on the inner peripheral side of the stator 16 along the axial direction, and flows into the pump chamber 14. The water that has flowed into the pump chamber 14 is pushed outward in the radial direction by the impeller 44, flows out from the outlet 58, and is discharged outside through the outflow path 60. This flow of water is indicated by the white arrows in FIG.

(4) Abnormal Operation State of Pump 10 Next, an operation state when foreign matter enters the pump 10 will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, foreign matter is contained in water, and foreign matter is caught between the lower part of the impeller 44 and the bottom plate 48 (point A), or between the rotor 18 and the cylindrical protrusion 30 (point B). Or C point), a foreign object is caught and the rotor 18 does not rotate and is locked.

  Then, the drive current flowing from the inverter circuit 66 to the stator winding 26 increases due to an overload, and when the lock detection circuit 72 detects this and exceeds the reference value, the lock detection signal R is sent to the control unit 70. Output.

  When the lock detection signal R is input, the control unit 70 instructs the PWM circuit 68 to perform control to reverse the rotation direction of the motor 12. In the motor 12, in order to reversely rotate, it stops once and rotates in the reverse direction again, so that the stop and start are performed, and since the rotation direction is the reverse direction, foreign matter caught between points A, B and C It is removed by stopping and rotating in the reverse direction.

  Accordingly, even if foreign matter enters the pump 10 and the motor 12 is locked, the foreign matter can be removed without disassembling the pump 10.

  However, the lock detection signal R continues to be input to the control unit 70 when foreign matter cannot be removed by this reverse rotation. Therefore, if the lock detection signal R is input even if the controller 70 continues to output the reverse rotation instruction signal for a predetermined time (for example, 10 seconds) or longer, the output is stopped to prevent the motor 12 from being heated. .

(Modification 1)
In the control of the above embodiment, when the lock detection signal R is input with a foreign object caught, the motor 12 is reversed. Foreign matter can also be removed. In this case, not only reverse rotation but also normal rotation is alternately performed, so that foreign matters can be more reliably removed.

  Further, if the interval between the forward rotation and the reverse rotation is shortened, vibrations are generated, and foreign matters can be easily removed.

(Modification 2)
In the above embodiment, the stator 16 is housed between the first casing 28 and the lid 34. However, the stator 16 may be molded instead.

(Modification 3)
In the above embodiment, the locked state of the motor 12 is set to the locked state when the drive current flowing from the inverter circuit 66 to the stator winding 26 becomes an overcurrent. A Hall IC may be provided, and it may be detected whether or not the lock state is established based on the rotation state of the rotor 18 detected from the Hall IC.

(Modification 4)
In the above embodiment, the wiring board having the drive circuit 64 is provided separately from the pump 10. However, the wiring board may be provided integrally in the vicinity of the stator 16.

(Modification 5)
In the above embodiment, the motor 12 is a brushless DC motor. However, another motor such as a synchronous motor may be used instead.

It is a longitudinal cross-sectional view of the pump which shows one Embodiment of this invention. It is a block diagram of the drive circuit of the motor in a pump similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Pump 12 Motor 14 Pump chamber 16 Stator 18 Rotor 20 Cavity 22 Stator iron core 24 Insulating layer 26 Stator winding 36 Permanent magnet 44 Impeller 52 Fixed shaft 64 Drive circuit 66 Inverter circuit 68 PWM circuit 70 Control part 72 Lock detection circuit

Claims (4)

An inner rotor type motor in which a rotor is rotatably arranged in a hollow portion on the inner peripheral side of a ring-shaped stator;
A pump chamber is arranged on one side of the hollow portion in the axial direction,
An impeller is arranged coaxially with the rotor and inside the pump chamber,
A fluid inflow port opens on the other axial side of the cavity,
An outlet is opened in the pump chamber located in the radially outward direction of the impeller,
When the impeller rotates together with the rotor, the fluid that has flowed into the inflow port passes through the hollow portion along the axial direction, reaches the pump chamber, and flows out from the outflow port.
Driving means for rotating the motor;
Lock detecting means for detecting a locked state of rotation of the rotor;
When the lock detection means detects a locked state, the control means for controlling the driving means to reversely rotate the impeller or alternately repeat reverse rotation and forward rotation;
The pump characterized by having. A fixed shaft is erected in the axial direction from the pump chamber,
The rotor is rotatably arranged with respect to the fixed shaft,
The rotor is ring-shaped;
The pump according to claim 1, wherein a fluid flows along an axial direction on an inner peripheral side of the ring-shaped rotor. The motor is a brushless DC motor;
A permanent magnet is arranged on the rotor,
The drive means includes an inverter circuit that outputs a drive current to a stator winding of each phase wound around a stator core of the stator, and a PWM circuit that outputs a PWM signal to each switching element of the inverter circuit The pump according to claim 1, comprising: A dishwasher characterized in that water is sprayed on tableware and the like using the pump according to claim 1.

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