# US 11,114,910 B2 · Method for manufacturing an armature for an EC motor

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,114,910 B2
- Document ID: US11114910B2
- Status: Granted
- Kind: B2
- Application number: 16/184,505
- Filed: 2018-11-08
- Published: 2019-05-09
- Granted: 2021-09-07
- Earliest claimed: 2017-11-08
- Assignees: C. & E. Fein GmbH
- Applicants: C.&E. Fein GmbH
- Inventors: Christoph Maier; Fabian Grass; Thomas Burkhardt
- Web page: https://patentgrep.com/patent/US11114910B2

## CPC

- H02K 1/28: Means for mounting or fastening rotating magnetic parts on to, or to, the rotor structures
- H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
- H02K 1/30: using intermediate parts, e.g. spiders
- H02K 7/04: Balancing means
- H02K 15/03: having permanent magnets
- H02K 15/12: Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines
- H02K 15/165: Balancing the rotors
- H02K 21/14: with magnets rotating within the armatures
- Y10T 29/49012: Rotor
- Y10T 29/53143: Motor or generator
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

An EC motor is provided having a stator, in which an armature is rotatably supported, the armature including an armature shaft, on which an armature core having a plurality of permanent magnets is held, the armature core being electrically insulated against the armature shaft with the aid of a casting compound, and a balance ring being provided on at least one axial end of the armature core, which is accommodated on the armature shaft by a central recess, a gap between the armature shaft and the central recess of the balance ring being filled with casting compound, and the permanent magnets being held in pockets of the armature core by casting compound.

## Claims

### Claim 1

A method for manufacturing an armature for an EC motor, the method comprising:
providing an armature shaft;
providing an armature core having pockets for accommodating at least one permanent magnet;
providing a balance ring on at least one axial end of the armature core;
fixing the permanent magnet in a pocket of the armature core;
placing the balance ring on an end of the armature core;
inserting the armature shaft, the armature core, and the at least one balance ring into a casting mold centered relative to each other, such that the balance ring abuts the axial end of the armature core;
closing the casting mold;
feeding casting compound under pressure into a gap between the armature core and the pocket having the permanent magnet via a sprue in the form of a gap between the balance ring and the armature shaft;
curing the casting compound; and
removing the armature from the casting mold.

### Claim 2 (depends on 1)

The method according to claim 1, wherein balance rings are placed on the armature core at both axial ends of the armature core and the casting compound is supplied from at least one side via sprues in the form of gaps between the balance rings and the armature shaft.

### Claim 3 (depends on 2)

The method according to claim 2, wherein each balance ring is sealed against the armature core by an annular projection on a side facing the armature core.

### Claim 4 (depends on 3)

The method according to claim 3, wherein the annular projection of each balance ring is flush with an outer surface of the balance ring.

### Claim 5 (depends on 3)

The method according to claim 3, wherein the permanent magnet is secured against an axial displacement on at least one end during the injection molding operation by an annular projection of a balance ring.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the balance ring is provided with form-fitting elements in the form of seams or grooves at a central recess.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the permanent magnet is fixed in its pocket by protruding noses of laminations of the armature core before the fixing by the casting compound takes place.