Pump for use in a vacuum cleaner

Abstract

A pump is for generating a suction for application to a vacuum cleaner dirty air inlet. There is a motor inside a motor outer casing and a fan outside the motor outer casing having a main inlet and a main outlet. The fan generates a main suction flow between the main inlet and the main outlet and creates a region of under pressure. This under pressure is used to drive a secondary flow between a cooling air inlet to the motor outer casing and a cooling air outlet from the motor outer casing. The secondary air flow is induced by making use of an under pressure generated by the fan.

1 . A pump for use in a vacuum cleaner to generate a suction for application to a vacuum cleaner dirty air inlet, comprising:
 a motor outer casing;   a motor part in the motor outer casing;   a fan outside the motor outer casing, driven by the motor part, having a main inlet and a main outlet, wherein the fan generates a main suction flow between the main inlet and the main outlet and creates a region of under pressure;   a cooling air inlet to the motor outer casing;   a cooling air outlet from the motor outer casing; and   a fluid coupling between the cooling air outlet and the region of under pressure such that a secondary flow of air is sucked through the cooling air inlet resulting in a cooling of the motor, wherein the cooling air inlet and the main suction flow are separated from each other.   
     
     
         2 . The pump as claimed in  claim 1 , wherein the fan is located inside a fan casing and wherein the region of under pressure created by the fan is located at least partially inside the fan casing and outside the motor outer casing. 
     
     
         3 . The pump as claimed in  claim 1 , wherein the region of under pressure created by the fan couples to an inlet side of the fan. 
     
     
         4 . The pump as claimed in  claim 3 , wherein the fluid coupling couples to a region of maximum under pressure at the inlet side of the fan. 
     
     
         5 . The pump as claimed in  claim 1 , wherein the region of under pressure created by the fan is located adjacent the motor outer casing couples to the inside of the motor outer casing. 
     
     
         6 . The pump as claimed in  claim 5 , wherein the fan has a front side outside the motor outer casing and a back side which faces and couples to the inside of the motor outer casing, and wherein the back side acts as a pump to generate said region of under pressure. 
     
     
         7 . The pump as claimed in  claim 6 , wherein the fluid coupling couples to a region of maximum under pressure within the front side of the fan or the back side of the fan. 
     
     
         8 . The pump as claimed in  claim 1 , wherein the main outlet is directed around the outside of the motor outer casing. 
     
     
         9 . The pump as claimed in  claim 1 , wherein the motor part comprising:
 a brushless dc motor; or   a permanent magnet dc motor.   
     
     
         10 . A pump and filter unit, comprising:
 the pump as claimed in  claim 1 ; and   a filter section downstream of the pump.   
     
     
         11 . A vacuum cleaner, comprising:
 a main body including the pump as claimed in  claim 1 ;   a vacuum cleaner dirty air inlet coupled to the main body to receive a suction generated by the pump; and   a dirt separation unit upstream of the pump.   
     
     
         12 . The vacuum cleaner as claimed in  claim 11 , further comprising a filter section through which a flow generated by the pump is passed, wherein the filter section is downstream of the pump. 
     
     
         13 . The vacuum cleaner as claimed in  claim 11 , further comprising control electronics, wherein the control electronics is cooled by the secondary flow of air. 
     
     
         14 . The vacuum cleaner as claimed in  claim 11 , further comprising control electronics, wherein the control electronics is cooled by the secondary flow of air, before the secondary flow of air enters the motor outer casing. 
     
     
         15 . A method of cooling a motor of a vacuum cleaner pump which is for driving a fan to generate a main suction flow and a region of under pressure, the main suction flow being for application to a vacuum cleaner dirty air inlet, and the motor being contained within a motor outer casing, the method comprising:
 providing a fluid coupling between a cooling air outlet of the motor outer casing and the region of under pressure, such that a secondary flow of air is sucked through the cooling air inlet resulting in a cooling of the motor, wherein the cooling air inlet and the main suction flow are separated from each other.   
     
     
         16 . The pump as claimed in  claim 1 , wherein the fan further comprises a pre motor filter to create a pressure drop so that pressure at the main inlet is below atmospheric pressure.