Encoder, motor with encoder, and servo system

Patent metadata

Field	Value
Publication number	US-9335185-B2
Application number	US-201414532003-A
Country	US
Kind code	B2
Filing date	Nov 4, 2014
Priority date	Nov 5, 2013
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

The encoder includes a plurality of slit tracks, a point light source, two first light-receiving arrays, two second light-receiving arrays, and a third light-receiving array. The plurality of slit tracks respectively comprises a plurality of reflection slits arranged along a measurement direction. The point light source is configured to emit diffusion light to the plurality of slit tracks. The two first light-receiving arrays are disposed sandwiching the point light source in a width direction substantially orthogonal to the measurement direction. The two second light-receiving arrays are disposed sandwiching the point light source in the measurement direction. The third light-receiving array is configured to receive light reflected by the slit track comprising an incremental pattern that differs in pitch from other incremental patterns, and is disposed at a position in a direction where the first light-receiving array is disposed than the point light source.

First claim

What is claimed is:

1. An encoder, comprising:
a plurality of slit tracks that respectively comprise a plurality of reflection slits arranged along a measurement direction;
a point light source configured to emit diffusion light to the plurality of slit tracks;
two first light-receiving arrays disposed sandwiching the point light source in a width direction substantially orthogonal to the measurement direction;
two second light-receiving arrays disposed sandwiching the point light source in the measurement direction; and
a third light-receiving array that is configured to receive light reflected by the slit track comprising an incremental pattern that differs in pitch from other incremental patterns, and is disposed at a position in a direction where the first light-receiving array is disposed than the point light source.

2. The encoder according to claim 1 , wherein:
the third light-receiving array is configured to receive light reflected by the slit track comprising the incremental pattern longer in pitch than other incremental patterns, and is disposed so as to sandwich the first light-receiving array with the point light source.

3. The encoder according to claim 2 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the third light-receiving array configured to receive light reflected by the slit track comprising the incremental pattern longer in pitch than other incremental patterns is disposed on the center axis side than the point light source.

4. The encoder according to claim 3 , wherein:
the two first light-receiving arrays are configured to receive light respectively reflected by two of the slit tracks comprising an absolute pattern; and
the two second light-receiving arrays are configured to receive light reflected by one of the slit tracks comprising an incremental pattern.

5. The encoder according to claim 2 , wherein:
the two first light-receiving arrays are configured to receive light respectively reflected by two of the slit tracks comprising an absolute pattern; and
the two second light-receiving arrays are configured to receive light reflected by one of the slit tracks comprising an incremental pattern.

6. The encoder according to claim 1 , wherein:
the third light-receiving array is configured to receive light reflected by the slit track comprising the incremental pattern shorter in pitch than other incremental patterns, and is disposed so as to sandwich the first light-receiving array with the point light source.

7. The encoder according to claim 6 , wherein:
the measurement direction is a circumferential direction with a center axis as the center; and
the third light-receiving array configured to receive light reflected by the slit track comprising the incremental pattern shorter in pitch than other incremental patterns is disposed on the side opposite the center axis than the point light source.

8. The encoder according to claim 7 , wherein:
the two first light-receiving arrays are configured to receive light respectively reflected by two of the slit tracks comprising an absolute pattern; and
the two second light-receiving arrays are configured to receive light reflected by one of the slit tracks comprising an incremental pattern.

9. The encoder according to claim 6 , wherein:
the two first light-receiving arrays are configured to receive light respectively reflected by two of the slit tracks comprising an absolute pattern; and
the two second light-receiving arrays are configured to receive light reflected by one of the slit tracks comprising an incremental pattern.

10. The encoder according to claim 1 , wherein:
the third light-receiving array is disposed between the two first light-receiving arrays.

11. The encoder according to claim 10 , wherein:
the two first light-receiving arrays are configured to receive light respectively reflected by two of the slit tracks comprising an absolute pattern; and
the two second light-receiving arrays are configured to receive light reflected by one of the slit tracks comprising an incremental pattern.

12. A motor with an encoder, comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator; and
the encoder according to claim 1 configured to detect at least one of a position and a velocity of the mover or the rotor.

13. A servo system comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator;
the encoder according to claim 1 configured to detect at least one of a position and a velocity of the mover or the rotor; and
a controller configured to control the liner motor or the rotary motor based on a detection result of the encoder.

14. An encoder, comprising:
a plurality of slit tracks that respectively comprise a plurality of reflection slits arranged along a measurement direction;
a point light source configured to emit diffusion light to the plurality of slit tracks;
two first light-receiving arrays disposed sandwiching the point light source in a width direction substantially orthogonal to the measurement direction;
two second light-receiving arrays disposed substantially sandwiching the point light source in the measurement direction; and
two third light-receiving arrays that are configured to receive light reflected by the slit track comprising an incremental pattern that differs in pitch from other incremental patterns, and are disposed substantially sandwiching the point light source in the measurement direction between the two first light-receiving arrays.

15. A motor with an encoder, comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator; and
the encoder according to claim 14 configured to detect at least one of a position and a velocity of the mover or the rotor.

16. A servo system comprising:
a linear motor wherein a mover moves with respect to a stator, or a rotary motor wherein a rotor rotates with respect to a stator;
the encoder according to claim 14 configured to detect at least one of a position and a velocity of the mover or the rotor; and
a controller configured to control the liner motor or the rotary motor based on a detection result of the encoder.

17. An encoder, comprising:
a plurality of slit tracks that respectively comprise a plurality of reflection slits arranged along a measurement direction;
means for emitting diffusion light to the plurality of slit tracks;
means for outputting a signal representing a low-accuracy absolute position within one rotation, disposed in duplicate sandwiching the means for emitting the diffusion light in a width direction substantially orthogonal to the measurement direction;
means for outputting a highly periodical repetition signal, disposed in duplicate sandwiching the means for emitting the diffusion light in the measurement direction; and
means for receiving light reflected by the slit track comprising an incremental pattern that differs in pitch from other incremental patterns, disposed at a position in a direction where the means for outputting a signal representing the low-accuracy absolute position within one rotation is disposed than the means for emitting the diffusion light.

Assignees

• Yaskawa Denki Seisakusho Kk

Inventors

• Yoshida Yasushi
• Matsutani Yasuhiro
• Yoshidomi Shiro
• Takada Hiroshi
• Arinaga Yuji
• Murokita Ikuma
• Harada Masanobu
• Kondo Hiroki

Classifications

• H02K11/0026

  Electricity · mapped topic

• G05B2219/37104

  Absolute encoder · CPC title

• G01D5/34746

  Linear encoders · CPC title

• H02K11/22

  Optical devices · CPC title

• G01D5/3473 Primary

  Circular or rotary encoders · CPC title