LINEAR MOTOR

• US 20150028697A1
• Filed: 06/23/2014
• Published: 01/29/2015
• Est. Priority Date: 07/29/2013
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Yaskawa Denki
• Original Assignee: Kabushiki Kaisha Yaskawa Denki
• Inventors: MAKINO, Shogo, ARINAGA, Yuji, OHTO, Motomichi
• Granted Patent: US 9,270,156 B2
• Time in Patent Office: Days
• US Class Current: 310/12.18
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: H02K 41/031 of the permanent magnet type
• CPC Class Codes: H02K 41/033 with armature and magnets on one member, the other member being a flux distributor

Abstract

A linear motor includes a stator and an armature that faces the stator with a gap therebetween. The stator has an elongated shape extending so as to cross a direction in which the stator faces the armature, and includes a plurality of salient poles that are arranged along a longitudinal direction of the stator and protrude toward the armature. The armature includes an armature core including a tooth that protrudes toward the stator, an armature winding wound around the tooth, a plurality of permanent magnets disposed on an end side of the tooth so as to be arranged along the longitudinal direction of the stator, and a magnetic-field sensor that detects a magnetic field which is generated by the plurality of permanent magnets and which passes through the plurality of salient poles.

Claims

1. A linear motor comprising:

a stator; and

an armature that faces the stator with a gap therebetween, wherein

the stator has an elongated shape extending so as to cross a direction in which the stator faces the armature, and includes a plurality of salient poles that are arranged along a longitudinal direction of the stator and protrude toward the armature, and

the armature includes

an armature core including a tooth that protrudes toward the stator,

an armature winding wound around the tooth,

a plurality of permanent magnets disposed on an end side of the tooth so as to be arranged along the longitudinal direction of the stator, and

a magnetic-field sensor that detects a magnetic field which is generated by the plurality of permanent magnets and which passes through the plurality of salient poles.

2. The linear motor according to claim 1, wherein the magnetic-field sensor is disposed so as to face any one of the plurality of salient poles with a gap therebetween.

3. The linear motor according to claim 1, wherein the magnetic-field sensor is disposed so as to correspond to at least one of the plurality of permanent magnets in the longitudinal direction of the stator, and is disposed on an outer side of the permanent magnet in a width direction of the stator.

4. The linear motor according to claim 3, wherein end portions of the plurality of salient poles extend to an outer side of end portions of the plurality of permanent magnets in the width direction of the stator, and the magnetic-field sensor faces any one of the plurality of salient poles from a side of the armature.

5. The linear motor according to claim 3, wherein the magnetic-field sensor faces any one of the plurality of salient poles from an outer side of the stator in the width direction of the stator.

6. The linear motor according to claim 1, wherein the magnetic-field sensor is fixed to the armature core via a connecting member made of a soft magnetic material.

7. The linear motor according to claim 1, wherein the magnetic-field sensor is one of a plurality of magnetic-field sensors arranged in the longitudinal direction of the stator.

8. The linear motor according to claim 7, wherein the tooth is one of a plurality of teeth arranged in the longitudinal direction of the stator, the armature winding is one of a plurality of armature windings that are respectively wound around the plurality of teeth and that respectively receive alternating currents of a plurality of phases, and the plurality of magnetic-field sensors are arranged for the respective phases of the alternating currents.

9. The linear motor according to claim 1, further comprising a measurement unit that measures, based on an output of the magnetic-field sensor, an amount of relative movement of the armature and the stator.