# US 2014/0152129 A1 · Double rotor stepping motor

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- Number: US 2014/0152129 A1
- Document ID: US20140152129A1
- Status: Published application
- Kind: A1
- Application number: 14/094,399
- Filed: 2013-12-02
- Published: 2014-06-05
- Earliest claimed: 2012-12-05
- Assignees: Thales
- Applicants: Thales
- Inventors: Stephane VEZAIN; Yannick BAUDASSE; Yasmina GAFARI
- Web page: https://patentgrep.com/patent/US20140152129A1

## CPC

- H02K 37/14: with magnets rotating within the armatures
- H02K 16/025: {with rotors and moving stators connected in a cascade (cascade arrangement of an asynchronous motor with another dynamo-electric motor or converter H02K17/34)}
- H02K 37/04: with rotors situated within the stators
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

In precision mechanical actuators, wherein a high precision stepping motor can notably be used in the actuating mechanisms of artificial satellites, a stepping motor comprises two rotors that rotate in opposite directions to generate a low-amplitude movement between one of the rotors and a stator. The first rotor comprises a first set of teeth distributed at a first pitch p1 and a second set of teeth distributed at a second pitch p2. The stator comprises N stator contacts comprising a plurality a of teeth distributed at the pitch p1, distributed at a third pitch equal to p1(a+1/N), and able to cooperate with the teeth of the first set. The second rotor comprises N rotor contacts comprising a plurality b of teeth distributed at the pitch p2, distributed at a fourth pitch equal to p1(b+1/N), and able to cooperate with the teeth of the second set of the first rotor.

## Claims

### Claim 1

A stepping motor comprising:
a stator comprising N stator contacts, where N is an integer greater than or equal to three,
a first rotor which is able to move with respect to the stator about an axis, the first rotor comprising a first set of teeth distributed at a first pitch p1, and a second set of teeth distributed at a second pitch p2, and
a second rotor which is able to move with respect to the first rotor about the axis, the second rotor comprising N rotor contacts,
the N stator contacts comprising a plurality a of teeth distributed at the pitch p1, where a is an integer, the N stator contacts being distributed on the stator at a third pitch equal to p1(a+1/N), the teeth of the first set being able to be aligned individually with one of the stator contacts, the passage from one alignment to a consecutive alignment causing the first rotor to move in a first direction with respect to the stator by the pitch p1/N,
the N rotor contacts comprising a plurality b of teeth distributed at the pitch p2, where b is an integer, the N rotor contacts being distributed on the second rotor at a fourth pitch equal to p2(b+1/N) and being able to be aligned individually with one of the teeth of the second set, the passage from one alignment to a consecutive alignment causing the second rotor to move in a second direction, opposite to the first direction, with respect to the first rotor by the pitch p2/N.

### Claim 2 (depends on 1)

The stepping motor according to claim 1, wherein the third pitch and the fourth pitch have the same value, and wherein the movements between the stator, the first rotor and the second rotor are rotational movements about the axis.

### Claim 3 (depends on 2)

The stepping motor according to claim 2, wherein each stator contact comprises a first ring portion, an internal surface of which is toothed with the pitch p1, the teeth of the ring portion being able to be aligned with teeth of the first set of the first rotor.

### Claim 4 (depends on 3)

The stepping motor according to claim 3, wherein each stator contact comprises a second ring portion, an internal surface of which is toothed with the pitch p1, the second ring portion being disposed symmetrically about the axis with respect to the first ring portion, the teeth of the second ring portion being able to be aligned with teeth of the first set of the first rotor.

### Claim 5 (depends on 4)

The stepping motor according to claim 4, wherein the first rotor and the second rotor each have N concentric rings distributed along the axis and electromagnetically isolated from one another, the first and second ring portions of each stator contact being aligned with one of the rings of the first rotor and with one of the rings of the second rotor so as to allow a magnetic field to flow between the first ring portion and the second ring portion.

### Claim 6 (depends on 2)

The stepping motor according to claim 2, wherein the first rotor comprises two parts that rotate as one about the axis, each part having N concentric rings distributed along the axis and electromagnetically isolated from one another, an external surface of each ring comprising teeth distributed at the pitch p1 and aligned between the various rings, an internal surface of each ring comprising teeth distributed at the pitch p2 and aligned between the various rings, the second rotor comprising two parts that rotate as one about the axis, each part of the second rotor having N concentric rings distributed along the axis and electromagnetically isolated from one another, an external surface of each ring comprising teeth distributed at the pitch p2 and offset with respect to the teeth of the other rings by the pitch p′2, each ring of the first rotor being aligned with one of the rings of the second rotor.

### Claim 7 (depends on 6)

The stepping motor according to claim 6, wherein each stator contact comprises four concentric ring portions, each ring portion being toothed with the pitch p1, for each stator contact, a first ring portion and a second ring portion being disposed symmetrically about the axis and cooperating with one of the rings of the first part of the first rotor and with one of the rings of the first part of the second rotor, a third ring portion and a fourth ring portion being disposed symmetrically about the axis and cooperating with one of the rings of the second part of the first rotor and with one of the rings of the second part of the second rotor.