GB2401911A

GB2401911A - Fan with cooling means for a hair dryer motor

Info

Publication number: GB2401911A
Application number: GB0311484A
Authority: GB
Inventors: Grand Lee
Original assignee: Johnson Electric SA
Current assignee: Johnson Electric SA
Priority date: 2003-05-20
Filing date: 2003-05-20
Publication date: 2004-11-24
Also published as: GB0311484D0

Abstract

A fan and motor assembly, for use in a hair dryer, comprises a fan 16 which is mounted to an output shaft of a motor (14 figure 1) such that a gap (21 figure 1) is formed between them. The fan 16 includes turbulence generating means which are arranged, in use, to generate an airflow in the gap 21 to cool the motor 14. The turbulence generating means may be apertures 22 formed in a base 18 of the fan 16, or may be a number of radially extending ribs 23 formed on a side of the base 18 adjacent the motor 14.

Description

This invention relates to motors and in particular to the cooling of an

electric motor in a hair dryer.

Typically, hair dryers employ an electric motor to drive a fan to generate air flow through the hair dryer and across heating coils to provide the desired flow of air.

There is a trend to demand lighter hair dryers which usually means a smaller motor delivering the same power to drive the fan This also reduces the air flow resistance as the motor normally provides a significant blockage in the air flow path. However, because the motor is smaller and does not obstruct the air flow path as much, the motor is not cooled by the air flow as fully as before. Also, as the motor is smaller, while providing the same or greater output, the need for cooling becomes greater.

Thus, there is a need for special cooling considerations for a motor sitting in the air shadow of the fan.

Accordingly, the present invention provides a hair dryer with a fan and motor assembly in which the fan has turbulence inducing means for inducing turbulence in the space between the motor and fan to bring cooling air flow into greater contact with the motor.

The turbulence inducing means may be holes in the base of the fan or ribs on the side of the fan base facing the motor and acting as auxiliary fan blades.

Two preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure I illustrates a typical hair dryer to which the present invention is applicable; Figure 2 illustrates a fan/motor combination in accordance with a first embodiment of the present invention; and Figure 3 illustrates a fan/motor combination in accordance with a second embodiment ofthe present invention.

Figure 1 is a sectional view through a typical hair dryer. The hair dryer functions to direct a flow of hot air towards a desired location and has housing 10 having an air passage 11 therethrough. The passage 11 has an inlet 12 and an outlet 13. Inside the passage 11 are heaters 15 for warming the air. Located within the passage and adjacent the inlet is a fan 16 powered by a motor 14. The fan 16 sucks air in through the inlet 12 and forces it around the motor 14, pass the heating coils 15 and out the outlet 13. The fan 16 has a number of radially extending fan blades 17 attached to one side of a base plate or disk 18. The base plate 18 extends generally in the radial direction although as shown in Figures 2 and 3, the preferred disk 18 has a noticeable curve or bow. The fan 16 is fixed to an output shaft of the motor 14 with the motor adjacent down wind side of the base plate 18 opposite the blades 17. Thus, in the air flow sense, the motor 14 is located in the shadow ofthe fan 16.

Previously, because of the size of the motor, there was sufficient pressure and turbulence to force the resulting air flow into the gap 21 between the fan 16 and the motor 14 to cool the motor 14. As the size of the motor decreases, the restriction in the air flow through the tubular passage decreases. Due to the air flowing pass, the gap 21 becomes a low pressure void resulting in insufficient cooling of the motor, especially in the region adjacent the output shaft.

In Figure 2, the preferred fan has a number of holes 22 formed in the base plate 18 so that in use, air is drawn into the gap 21 between the motor 14 and the fan 16 and out through the holes 22 in the base plate 18, thus providing air flow into this region which cools the end of the motor 14 adjacent the fan 16. This results in reduced temperature build up at this end of the motor and in particular, the output bearing which otherwise may overheat and fail. The holes 22 generate turbulence in the gap 21 by creating a circulating air flow path.

In a second embodiment shown in Figure 3, the base plate 18 has a number of ribs or auxiliary fan blades 23 facing the motor 14 and located within the gap 21 between the motor 14 and fan 16. In use, the ribs 23 generate turbulence within the gap 21 resulting in a flow of air into and through this region thereby cooling the motor 14.

Thus, by providing turbulence generators on the fan to create turbulence in the gap between the motor and fan, cooling of the motor can be achieved even when the motor is smaller with a greater percentage of the motor being located within the shadow ofthe fan.

Claims

Claims 1. A motor and fan assembly for use in a hair dryer comprising: a

motor having an output shaft; a fan having a generally radially extending base and a plurality of radial fan blades located on a side of the base opposite the motor, the fan being fitted to the output shaft and spaced from an end of the motor by a gap; characterized in that the fan has turbulence generating means arranged to generate air flow in the gap between the motor and the fan base adjacent the output I O shaft.
2. An assembly as defined in claim I wherein the turbulence generating means comprises at least one through hole formed in the base of the fan adjacent the motor output shaft.
3. An assembly according to claim wherein the turbulence generating means comprises a plurality of radially extending ribs formed on a side of the base adjacent the motor and extending into a void formed between an end of the motor and the fan base.
4. A fan motor assembly for a hair dryer substantially as hereinbefore described with reference to the accompanying drawings.