Method of making a rotor for an electric motor

• US 20060055264A1
• Filed: 09/07/2005
• Published: 03/16/2006
• Est. Priority Date: 09/14/2004
• Status: Abandoned Application

• Current Assignee: Pierburg Pump Technology UK Limited (Rheinmetall AG)
• Original Assignee: Pierburg Pump Technology UK Limited (Rheinmetall AG)
• Inventors: Sadler, Christopher, Johnson, Raymond Martin, Buttery, Tim P.
• Application Number:
  US11/220,832
• Publication Number:
  US 20060055264A1
• Time in Patent Office: Days
• US Class Current: 310/156.230
• CPC Class Codes: F04D 13/0633 Details of the bearings
• CPC Class Codes: F04D 13/064 Details of the magnetic circuit
• CPC Class Codes: F04D 29/046 Bearings
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 15/03 having permanent magnets
• CPC Class Codes: H02K 5/128 using air-gap sleeves or air-gap discs
• CPC Class Codes: H02K 5/1677 radially supporting the rotor around a fixed spindle; radially supporting the rotor directly
• CPC Class Codes: H02K 7/14 Structural association with mechanical loads, e.g. with hand-held machine tools or fans with fan or impeller for cooling the machine H02K9/06
• CPC Class Codes: Y10T 29/49009 Dynamoelectric machine

Abstract

A method of making a rotor for an electric motor, the rotor including a magnet assembly and a bearing, the bearing being adapted for supporting the rotor on a shaft whilst permitting rotation of the rotor about the shaft, the method including the steps of engaging the bearing with a bearing support tool, engaging a first engagement formation provided on the magnet assembly with a corresponding second engagement formation provided on the bearing such that movement of the magnet assembly with respect to the bearing is restricted, and moulding a polymeric rotor casing around the magnet assembly and bearing so that the magnet assembly and bearing are retained by the rotor casing.

Claims

1. A method of making a rotor for an electric motor, the rotor including a magnet assembly and a bearing, the bearing being adapted for supporting the rotor on a shaft whilst permitting rotation of the rotor about the shaft, the method including the steps of engaging the bearing with a bearing support tool, engaging a first engagement formation provided on the magnet assembly with a corresponding second engagement formation provided on the bearing such that movement of the magnet assembly with respect to the bearing is restricted, and moulding a polymeric rotor casing around the magnet assembly and bearing so that the magnet assembly and bearing are retained by the rotor casing.

2. A method according to claim 1 wherein the magnet assembly is tubular and the first engagement formation comprises a shoulder formation which extends radially inwardly from an interior surface of the magnet assembly.

3. A method according to claim 1 wherein the bearing is tubular and the second engagement formation comprises a shoulder formation which extends radially outwardly from an exterior surface of the bearing.

4. A method according to claim 1 wherein the magnet assembly includes at least one magnet and a yoke made from a magnetisable material such as iron.

5. A method according to claim 4 wherein the method further includes the step of engaging a third engagement formation provided on either the yoke or the magnet, the third engagement formation restricting movement of the yoke relative to the magnet.

6. A method according to claim 5 wherein the yoke is tubular and the third engagement formation comprises a shoulder formation which extends radially inwardly from an interior surface of the yoke.

7. A method according to claim 1 wherein one or both ends of the magnet assembly may be spaced from the bearing such that, during over-moulding of the rotor casing, the polymer from which the rotor casing is made is forced into the space or spaces between the bearing and the magnet assembly,

8. A method according to claim 1 wherein the rotor is adapted for use in driving a fluid pump in which pumping is achieved by rotation of a pumping element in a pump chamber, and the method further includes the step of moulding the pumping element integrally formed with the rotor casing.

9. A rotor for an electric motor, the rotor including a magnet assembly and a bearing, the bearing being adapted for supporting the rotor on a shaft whilst permitting rotation of the rotor about the shaft, a first engagement formation provided on the magnet assembly being engaged with a corresponding second engagement formation provided on the bearing such that movement of the magnet assembly with respect to the bearing is restricted, and there being a polymeric rotor casing moulded around the magnet assembly and bearing so that the magnet assembly and bearing are retained by the rotor casing.