# US 2017/0257015 A1 · Linear actuator

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- Number: US 2017/0257015 A1
- Document ID: US20170257015A1
- Status: Published application
- Kind: A1
- Application number: 15/523,357
- Filed: 2015-10-27
- Published: 2017-09-07
- Earliest claimed: 2014-10-29
- Assignees: KYB Corporation
- Applicants: KYB Corporation
- Inventors: Kousuke SATOU
- Web page: https://patentgrep.com/patent/US20170257015A1

## CPC

- H02K 41/031: {of the permanent magnet type}
- H02K 5/1672: {radially supporting the rotary shaft at both ends of the rotor (H02K5/1677 takes precedence)}
- H02K 2207/03: Tubular motors, i.e. rotary motors mounted inside a tube, e.g. for blinds
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})

## Abstract

A linear actuator includes: a first tube provided with coils placed there inside, the coils being held by a yoke; a second tube mounted on an outer circumference of the first tube; a rod fixed to an end of the second tube at one end; and permanent magnets held by the rod while being lined up in an axial direction. When the first tube and the second tube are at a fully contracted position, a gap is provided between an end face of an outer tube of the second tube and an opposing face of a base portion of the first tube.

## Claims

### Claim 1

A linear actuator, comprising:
a first tube provided with a plurality of coils placed there inside, the plurality of coils being held by a tubular yoke;
a second tube mounted on an outer circumference of the first tube so as to be relatively displaceable in an axial direction;
a rod fixed to an end of the second tube at one end so as to be movable in the yoke in the axial direction; and
a plurality of permanent magnets held by the rod while being lined up in the axial direction, the plurality of permanent magnets being arranged so as to oppose the plurality of coils,
wherein
the second tube includes an outer tube portion into which the first tube is inserted from one end side,
the first tube includes: an inner tube portion that is inserted into the outer tube portion; and a large diameter portion that is continuous with the inner tube portion in the axial direction, the large diameter portion having a larger diameter than that of the inner tube portion and opposing the one end side of the outer tube portion in the axial direction, and
when the first tube and the second tube are at a fully contracted position, a gap is provided between the one end side of the outer tube portion and the large diameter portion.

### Claim 2 (depends on 1)

The linear actuator according to claim 1,
wherein
the second tube includes a closing portion for closing the other end side of the outer tube portion,
the first tube includes an opposing portion opposing the closing portion in the axial direction, and
when the first tube and the second tube are at the fully contracted position, contact between the closing portion and the opposing portion restricts relative displacements of the first tube and the second tube.

### Claim 3 (depends on 2)

The linear actuator according to claim 2,
wherein
one of the closing portion and the opposing portion has a projected portion projecting toward another of the closing portion and the opposing portion.

### Claim 4 (depends on 3)

The linear actuator according to claim 3,
wherein
the projected portion is provided on an outer circumferential edge of the closing portion or the opposing portion.

### Claim 5 (depends on 2)

The linear actuator according to claim 2,
wherein
a projected portion projecting toward the opposing portion is provided on an outer circumferential side of the closing portion, and
the closing portion and the outer tube portion are coupled to each other with the projected portion.

### Claim 6 (depends on 1)

The linear actuator according to claim 1,
wherein
when the first tube and the second tube are at the fully contracted position, a part of the permanent magnets extends out from the coils toward the other end side of the second tube.

### Claim 7 (depends on 1)

The linear actuator according to claim 1,
wherein
a joint shaft rotatably supported by an external member is mounted on the large diameter portion.