Electronically commutated drive system for vacuum cleaner

• US 20040135537A1
• Filed: 01/09/2003
• Published: 07/15/2004
• Est. Priority Date: 01/09/2003
• Status: Active Grant

• Current Assignee: Royal Appliance Manufacturing Company (Techtronic Industries Company Limited)
• Original Assignee: Royal Appliance Manufacturing Company (Techtronic Industries Company Limited)
• Inventors: Conner, Michael P., McKee, Robert N.
• Granted Patent: US 7,076,830 B2
• Time in Patent Office: Days
• US Class Current: 318/701
• CPC Class Codes: A01D 34/82 Other details
• CPC Class Codes: A47L 5/28 Suction cleaners with handles and nozzles fixed on the casings, e.g. wheeled suction cleaners with steering handle A47L5/24 takes precedence
• CPC Class Codes: A47L 9/009 Carrying-vehicles; Arrangements of trollies or wheels; Means for avoiding mechanical obstacles
• CPC Class Codes: A47L 9/2805 Parameters or conditions being sensed
• CPC Class Codes: A47L 9/2842 Suction motors or blowers
• CPC Class Codes: A47L 9/2852 Elements for displacement of the vacuum cleaner or the accessories therefor, e.g. wheels, casters or nozzles
• CPC Class Codes: A47L 9/2857 User input or output elements for control, e.g. buttons, switches or displays

Abstract

A self-propelled appliance, such as a vacuum cleaner includes a magnetic field sensor and magnet. A relative position between the magnetic field sensor and the magnet can be changed by a user of the appliance. The magnetic field sensor generates a signal indicating a magnetic field sensed by the sensor. Therefore, the magnetic field sensor signal indicates the relative position of the magnet to the sensor. This relative position signal is interpreted as a speed and direction request for a means for propelling the appliance. The magnetic filed sensor is, for example, a Hall effect sensor. The means for propelling includes, for example, a brushless d.c motor, sensorless motor or switched reluctance motor. Forward and reverse propulsion is provided without the use of a clutch. The appliance includes a reduced number of wearing components.

Claims

1. An appliance comprising:

an electric motor;

at least one drive wheel operatively connected to the electric motor;

a controller electrically connected to the electric motor, the controller being operative to drive the electric motor, in a forward direction or a reverse direction, based on at least one signal, and

a Hall effect based sensor circuit operative to sense a drive effort desired by a vacuum cleaner user and provide the at least one signal to the controller.

2. The appliance of claim 1 wherein the electric motor comprises:

a brushless d.c. motor.

3. The appliance of claim 1 wherein the electric motor comprises:

a sensorless motor.

4. The appliance of claim 1 wherein the electric motor comprises:

a switched reluctance motor.

5. The appliance of claim 1 wherein the controller comprises:

a three phase motor bridge; and

a three phase motor bridge motor controller integrated circuit.

6. The appliance of claim 1 wherein the controller comprises:

a two phase motor bridge; and

a two phase motor bridge motor controller integrated circuit.

7. The appliance of claim 1 wherein the Hall effect based sensor comprises:

a first magnet;

a Hall effect sensor positioned adjacent the magnet, the magnet and Hall effect sensor being disposed for relative movement therebetween by the vacuum cleaner user.

8. The appliance of claim 7 further comprising:

a second magnet disposed on a side of the Hall effect sensor opposite the first magnet, the magnets having similar magnetic properties and arranged so that a pole of one magnet faces a like pole of the other magnet.

9. The appliance of claim 1 wherein the Hall effect based sensor circuit comprises:

a comparator operative to compare a field signal from a Hall effect sensor to a threshold and generate a direction signal based on the comparison.

10. The appliance of claim 9 wherein the Hall effect based sensor circuit comprises:

a non-inverting amplifier circuit operative to generate a first speed request signal related to a field signal, at an output of the non-inverting amplifier circuit, when the field signal is within a first range;

an inverting amplifier circuit operative to generate a second speed request signal related to the field signal, at an output of the inverting amplifier circuit, when the field signal is within a second range; and

,

a coupling circuit operative to interconnect the output of the non-inverting amplifier and the inverting amplifier and thereby generate a unified speed request signal indicative of the first speed request signal or the second speed request signal depending on whether the field signal is in the first range or the second range.

11. The appliance of claim 1 wherein the Hall effect based sensor circuit comprises:

a non-inverting amplifier circuit operative to generate a first speed request signal related to a field signal, at an output of the non-inverting amplifier circuit, when the field signal is within a first range;

an inverting amplifier circuit operative to generate a second speed request signal related to the field signal, at an output of the inverting amplifier circuit, when the field signal is within a second range; and

,

a coupling circuit operative to interconnect the output of the non-inverting amplifier and the inverting amplifier and thereby generate a unified speed request signal indicative of the first speed request signal or the second speed request signal depending on whether the field signal is in the first range or the second range.

12. The appliance of claim 1 wherein the Hall effect based sensor circuit comprises:

means for extracting requested speed and direction information from measurement of a magnetic field.

13. The appliance of claim 7 further comprising:

a neutral return spring operative to return a relative spacing between the first magnet and the Hall effect sensor to a neutral distance when the vacuum cleaner user is not effecting relative movement between the first magnet and the second magnet.

14. The appliance of claim 13 wherein the neutral return spring comprises a polymer material.

15. The appliance of claim 5 wherein the three phase motor bridge controller integrated circuit is operative to receive a speed signal and a direction signal.

16. The appliance of claim 1 wherein the controller comprise a micro-controller.

17. The appliance of claim 1 wherein the controller includes a soft start circuit.

18. The appliance of claim 1 wherein the controller includes a high speed/low speed circuit.

19. The appliance of claim 17 wherein the controller includes a high speed/low speed circuit.

20. An upright vacuum cleaner comprising:

a nozzle base;

an upright housing;

an electrically commutated d.c. electric motor mounted one of the nozzle base and the upright housing;

at least one drive wheel operatively connected to the d.c. electric motor;

a controller connected to the electric motor, the controller being operative to drive the electric motor at a plurality of speeds, in a forward direction or a reverse direction based on a speed signal and a direction signal;

a first magnet;

a second magnet disposed in spaced relation to the first magnet, a pole of the first magnet facing a like pole of the second magnet;

a Hall effect sensor disposed between the first magnet and the second magnet, the Hall effect sensor being operative to generate a field signal indicative of a magnetic field at the location of the Hall effect sensor;

means for changing a relative position of the magnets and Hall effect sensor;

means for generating a speed request signal from the field signal;

means for generating a direction signal from the field signal; and

,

means for selectively low pass filtering the speed request signal when it changes to request a higher speed.

21. The upright vacuum cleaner of claim 20 wherein the means for changing a relative position of the magnets and Hall effect sensor comprises:

a first mounting structure for supporting the first and second magnets;

a second mounting structure for supporting the Hall effect sensor, the first mounting structure being disposed for relative movement in relation to the second mounting structure when an external force is applied to the first mounting surface in a movement direction; and

,

a neutral return spring, for establishing a nominal relative position between the first and second magnets and the Hall effect sensor when an external force is not applied to the first mounting surface in a movement direction.

22. The upright vacuum cleaner of claim 21 wherein the neutral return spring comprises:

a polymer material.

23. The upright vacuum cleaner of claim 20 wherein the means for generating a speed request signal further comprises:

a means for providing a deadband in the speed request signal.

24. The upright vacuum cleaner of claim 20 wherein the means for generating a speed request signal comprises:

a non inverting amplifier circuit having a non inverted output;

an inverting amplifier circuit having an inverted output; and

,

a coupling circuit for combining the non inverting output and the inverting output to generate the speed signal.

25. The upright vacuum cleaner of claim 23 wherein the means for generating a speed request signal and means for providing a deadband comprise:

a non inverting amplifier circuit operative to provide a non inverted output based on the field signal and a reference;

an inverting amplifier circuit operative to provide an inverted output based on the field signal and the reference;

a coupling circuit for combining the non inverting output and the inverting output to generate the speed signal.

26. The upright vacuum cleaner of claim 20 wherein the means for selectively low pass filtering comprises:

a buffer amplifier;

a resistor having a first terminal and a second terminal;

a diode having a first terminal and a second terminal;

a capacitor having a first terminal and a second terminal, wherein the first terminal of the resistor and the first terminal of the diode are connected to an output of the buffer amplifier, the second terminal of the resistor, the second terminal of the diode, and the first terminal of the capacitor are connected together at an output node, and the second terminal of the capacitor is connected to a reference node.

27. A method of moving a self driven appliance:

changing a relative distance between a magnet and a magnetic field sensor to indicate a desired motion;

measuring a magnetic field at the position of the magnetic field sensor;

interpreting the measured magnetic field as a requested speed and direction; and

,

driving an electronically commutated motor according to the requested speed and direction.

28. The method of claim 27 wherein changing the relative distance between the magnet and magnetic field sensor comprises:

moving a handle element of the appliance, attached to one of the magnet and the magnetic field sensor, in a direction of the desired motion.

29. The method of claim 27 wherein measuring a magnetic field comprises:

measuring a Hall effect related to the magnetic field.

30. The method of claim 27 wherein interpreting the measured magnetic field comprises:

calculating a difference between a magnetic field signal and a reference signal;

interpreting a magnitude of the difference between the magnetic field signal and the reference signal as a speed request; and

,

interpreting a sign of the difference between the magnetic field signal and the reference signal as a direction request.