WO2000057064A1

WO2000057064A1 - Insulated fan

Info

Publication number: WO2000057064A1
Application number: PCT/TR1999/000015
Authority: WO
Inventors: Ridvan EGİN; Aydin Bahadir; M. Burçak ASLAN
Original assignee: Türk Elektri̇k Endüstri̇si̇ A.Ş.
Priority date: 1999-03-23
Filing date: 1999-03-23
Publication date: 2000-09-28
Also published as: TR200102654T2; AU3352599A

Abstract

This is an insulated fan obtained by placing using plastic insert moulding method an appropriate nut fitting motor shaft onto the hub of the fan body preferably of aluminium material to ensure insulation from inner parts of the motor as the fans of wet/dry vacuum cleaner apparels.

Description

INSULATED FAN

Hereby invention is concerned with ensuring electrical insulation of fans in contact with liquids in applications such as wet/dry vacuum cleaner apparels and alike, thus with preventing liquid leakage to motor and obtaining a less unbalanced motor structure.

In the known wet/dry vacuum cleaner motors, armature group and fan are assembled on the insulated shaft. In order to ensure presence of a double layer electrical insulation, slot insulation and further to that plastic injection over rotor shaft is needed. The outer diameter of the shaft fitted in the inner diameter of armature is to be held smaller owing to plastic injection. Reducing the diameter of the shaft further would, in turn, affect dynamic behaviour of armature. Especially, thinner shaft in compact motors would cause the armature having undesirable behaviours as regard to the rotor dynamics. Moreover insulating the shaft is costly and this is a disadvantage.

Unbalance of the fan assembly at the shaft end might be excessive. Moreover in the course of assembly of the fan, there is the concentricity problem and a result of that the balance of the motor sustains deterioration.

To solve the insulation problem, it has been considered using plastic fan instead of insulating the shaft. However, owing to plastic fan having strength problems at higher revolutions, no attempt has been made to put the same in operation at higher revolutions.

With the invention, it has been considered as objective to ascertain electrical insulation of the fan having contact with wet substances in applications such as wet/dry vacuum cleaners and to solve concentricity problems in the course of manufacturing. Figure 1 is the view before the insulated fan hub is formed.

Figure 2 is the view of the fan lower plate prepared by fan hub cast.

Figure 3 is the view as exploded of fan blades of the insulated fan lower plate and its connection to the upper plate.

Figure 4 is the three dimensional section view taken laterally of the insulated fan.

Figure 5 is three dimensional view from bottom of the insulated fan.

Figure 6 is the three dimensional view from the top of the insulated fan.

The numbering of the pieces which for the subject fan are as follows:

1) Fixing openings

2) Nut

3) Lower plate

4) Rivet holes

5) Rivet claws

6) Fan blades

7) Fan hub

8) Upper plate

9) Moisture proof set

Non-insulated fan is formed by joining lower plate (3), in the medium part of which fan hub (7) is formed through insert cast, to upper plate (8) using fan blades (6).

For insert moulding process, fixing openings are located (1) to hub portion of the lower aluminium plate. The position of the fixing openings (1) are to be symmetrical with respect to each other in order to ensure balance. The distances of the openings to the hub (1) are adjusted according to the varying diameter of the lower plate (3) with changing size of the motor. The number of the openings, may vary for the moulding on both surfaces, hold up each other strongly.

The nut (2) used for the assembly of the fan is attached to the shaft within the mould. The nut (2) is located in the mould such that it is concentric with the lower plate (3).The positioning of the nut (2) should be at optimum level. Plastic material flows through the fixing openings to the other side by the injection process. A concentric fan hub, in which a nut is located, is obtained on the lower plate. Forming the fan hub in this way (7) ensures the nut (2) being fixed to lower plate (3) with electrical insulation made there of.

A moisture proof set is formed (9) by provision of an outward slope of the edge which is formed by the moulding process on the lower surface of the lower plate (3) and away from the hub. The outer edge of the moisture proof set (9) is provided with a slope outwards to enable re-directing of the moisture coming from outside. In this way the effect of the moisture and detergents on the bearings is minimised.

The insulation thus ascertained through insulated fan which provides solution to the quality and balance problems arising due to insulating the shaft. Without insulating the shaft diameter will be thicker and this allows to step up higher speeds. Moreover the existence of a heavy and concentric moulding in which a nut is located, at the hub portion (7) of the insulated fan is effective in terms of ensuring a much more balanced rotation.

After the moulding of the hub at the centre of the lower plate (3) fan blades (6) are assembled properly to the fixing openings on the plate (3) through rivet claws (5) which the blades (6) have. To enable fixing of the blades (6), rivet claws (5) are punched from the other side. The height of the rivet claws (5) to be at a certain amount for these to originate no balance problem. Afterwards, the upper plate of the fan is inserted over the blades through the rivet claws and the insulated fan is formed again by punching rivet claws (5). Fan blades are located in a curved shape to guide air and water in the medium between lower and upper plates. The curved shape of the fan blades can be varied depending on the diameter and the efficiency of the fan.

Fan is assembled to the armature group by fastening the nut in the fan hub to the shaft end. To allow an easier assembly the upper portion of the fan hub is manufactured in a hexagonal form. The nut is positioned during the moulding of the hub (2) as such to tighten when the shaft rotates.

Claims

1. An insulated fan, comprising an upper plate (8), a lower plate (3) and fan blades (6) ensuring connection to each other of these both plates, having a concentric fan hub (7) in which a nut is located, characterised in that, in order to solve balance problems and to use non-insulated shafts, a nut fastened to the tip of a shaft as such that a portion of that nut remains over the upper face of the lower plate (3) whereas another portion there of below the same plate after this latter is positioned concentrically inside a mould, on which the plastic material is injected, where plastic penetrates from one face to the other through fixing openings (1) symmetrically located from each other at a specific distance from the centre, determined in accordance with the diameter the lower (3) and the upper plates (8) have, and cool down so as to form a centred fan hub (7) with nut therein.

2. An insulated fan as specified in claim 1 characterised in that, in order to prevent the moisture penetration to the motor section of moisture, a moisture proof set (9) is formed by placing vertical to lower plate (3) surface the outer diameter remote from the centre of the portion remaining on the lower surface of fan hub (7).

3. An insulated fan as specified in claims 1 and 2, characterised in that the said moisture proof set (9) is outwardly inclined preferably on its outer faces.