Device for a vacuum cleaner and a method for cooling a motor

• US 5,737,798 A
• Filed: 09/27/1996
• Issued: 04/14/1998
• Est. Priority Date: 11/02/1993
• Status: Expired due to Fees

• Current Assignee: Aktiebolaget Electrolux
• Original Assignee: Aktiebolaget Electrolux
• Inventors: Moren, Lars Gunnar, Wiss, Christer Caleb Ingemar, Lindmark, Magnus Carl Wilhelm
• Primary Examiner(s): MOORE, CHRISTOPHER K
• Application Number:
  US08/720,075
• Time in Patent Office: 564 Days
• Field of Search: 15/412, 15/413
• US Class Current: 15/413
• CPC Class Codes: A47L 9/22 Mountings for motor fan assemblies
• CPC Class Codes: F04D 25/082 the unit having provision for cooling the motor
• CPC Class Codes: F04D 25/166 using fans
• CPC Class Codes: F04D 29/5806 Cooling the drive system

Abstract

A vacuum cleaner having a suction nozzle and a dust bag (12) which is connected to the nozzle, for instance, by a tube connection, and a turbo-fan unit (27) driven by an electric motor and placed after the dust bag seen in the flow direction. The impeller (29) of the turbo-fan unit is driven at a speed above 50,000 rpm. A primary air stream created by the turbo-fan unit (27) leaves the unit via an outlet (30) to atmosphere. The vacuum cleaner also creates a secondary air stream which at least partially cools the electric motor (32) and which flows into the electric motor via one or several cooling air inlets (44) which are separated from the primary air stream. The secondary air stream can be created by a cooling fan which is separate or integral with the impeller, by a venturi-type nozzle, or by suction created by the impeller. The primary air stream flows in one direction through a channel surrounding a motor shell and the secondary air stream flows in a second, opposite direction through the motor shell and is thereafter redirected and mixed with the primary air stream.

Claims

1. A device for cooling an electric motor for a turbo-fan unit, the motor having a shaft supporting a turbo-fan impeller which is rotatable so as to create a primary air stream which escapes from the turbo-fan unit via an outlet, said device comprising a motor shell having first and second end walls each having a hub part in which the shaft is supported, and means for creating a secondary air stream which at least partially cools the electric motor and flows into the motor shell through at least one cooling air inlet, said at least one cooling air inlet being separated from the primary air stream and being formed in the second end wall so as to permit the secondary air stream to flow adjacent to the hub part in the second end wall, thereby helping to provide cooling to the hub part in the second end wall.

2. A device according to claim 1, wherein said secondary air stream creating means is a cooling air fan which is arranged at the same side of the motor shell as the turbo-fan impeller.

3. A device according to claim 2, wherein the turbo-fan impeller and the cooling air fan are placed outside the first end wall.

4. A device according to claim 3, wherein the cooling air flows from the electric motor through at least one outlet opening in the first end wall, said at least one outlet opening being located near the hub part in which the shaft is supported.

5. A device according to claim 3, wherein the cooling air fan is arranged in close proximity to the first end wall.

6. A device according to claim 2, wherein the cooling air fan is a radial fan.

7. A device according to claim 2, wherein the cooling air fan is a mainly flat plate.

8. A device according to claim 2, wherein the turbo-fan impeller and the cooling air fan are an integrated unit, the turbo-fan impeller being on one side of the unit while the cooling air fan is on the other side of the unit and faces the electric motor.

9. A device according to claim 1, wherein the secondary air stream enters into the primary air stream near the outlet of the turbo-fan unit.

10. A method for cooling a high speed vacuum cleaner motor, comprising the steps of:

(a) generating a primary air stream using an impeller rotatably driven by the motor, and directing the primary air stream over an outer surface of said motor;

(b) generating a secondary air stream using a cooling fan located on an opposite side of the motor as the impeller, and directing the secondary air stream through an interior of said motor;

(c) mixing said secondary air stream with said primary air stream; and

(d) exhausting the mixture of said primary and secondary air streams from the vacuum cleaner.

11. A method for cooling a motor according to claim 10, wherein said primary air stream flows in a first direction over said motor and said secondary air stream flows in a second direction through said motor, said second direction being generally opposite to said first direction.

12. A device for cooling an electric motor for a turbo-fan unit, the motor having a shaft supporting a turbo-fan impeller which is placed outside a shell of the motor and which rotates with a speed above 50,000 rpm thereby creating a primary air stream which escapes from the turbo-fan unit via an outlet, said device comprising:

means for creating a secondary air stream which at least partially cools the electric motor and flows into the motor shell through at least one cooling air inlet, said at least one cooling air inlet being separated from the primary air stream; and

a deflector plate for directing the secondary air stream in generally the same direction as the primary air stream before the primary and secondary air streams merge.

13. The device of claim 12, wherein the secondary air stream creating means is a cooling air fan which is arranged at the same side of the motor shell as the turbo-fan impeller.

14. The device of claim 12, wherein the secondary air stream creating means is a venturi passage.

15. A fan unit for a vacuum cleaner, said fan unit comprising:

a motor having a rotatable shaft with a fan impeller secured thereto, said motor being operable to rotate the fan impeller so as to create a primary air stream;

a motor shell enclosing the motor, said motor shell defining an inlet passage and an outlet passage;

an outer shell disposed around the motor shell, said outer shell cooperating with the motor shell to define a venturi air passage through which the primary air stream may flow, said venturi passage being connected to the outlet passage of the motor shell and being operable to create a secondary air stream that enters the motor shell through the inlet passage and exits the motor shell through the outlet passage, thereby helping to provide cooling to the motor.