Rotary encoder

Patent metadata

Field	Value
Publication number	US-10832878-B2
Application number	US-201916382241-A
Country	US
Kind code	B2
Filing date	Apr 12, 2019
Priority date	Oct 18, 2016
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

A rotary encoder includes a shaft and an encoder mechanism that holds the shaft in a rotatably inserted state and detects a rotation direction and a rotation angle of the shaft. The encoder mechanism includes a substrate that rotatably holds the shaft, an insulator portion and a resistor portion provided on one surface of the substrate and alternately provided in the rotation direction of the shaft, a rotor attached to the shaft so as to be integrally rotatable with the shaft, and a slider that is attached to the rotor and alternately slidably contacts the insulator portion and the resistor portion by rotation of the shaft. The insulator portion includes a base material made of a resin, spherical silica, and a fluororesin filler.

First claim

What is claimed is:

1. A rotary encoder comprising:
a shaft; and
an encoder mechanism that holds the shaft in a rotatably inserted state and detects a rotation direction and a rotation angle of the shaft; wherein
the encoder mechanism includes:
a substrate that rotatably holds the shaft;
an insulator portion and resistor portions provided on one surface of the substrate and alternately provided in the rotation direction of the shaft;
a rotor attached to the shaft so as to be integrally rotatable with the shaft; and
a slider that is attached to the rotor and alternately contacts the insulator portion and the resistor portions in a sliding manner by rotation of the shaft;

the insulator portion includes a base material made of a resin, spherical silica, and a fluororesin filler; and
an average particle diameter of the spherical silica is about 0.4 μm or more and about 0.8 μm or less.

2. The rotary encoder according to claim 1 , wherein a content ratio of the spherical silica included in the insulator portion is about 5 vol % or more and about 50 vol % or less, a content ratio of the fluororesin filler included in the insulator portion is about 1 vol % or more and about 20 vol % or less, and a sum of the content ratio of the spherical silica and the content ratio of the fluororesin filler is 50 vol % or less.

3. The rotary encoder according to claim 1 , wherein an average particle diameter of the fluororesin filler is about 50 nm or more and about 800 nm or less.

4. The rotary encoder according to claim 1 , wherein the fluororesin filler is polytetrafluoroethylene.

5. The rotary encoder according to claim 1 , wherein the base material is an epoxy resin.

6. The rotary encoder according to claim 1 , wherein one surface side of the insulator portion facing the slider has less spherical silica and more fluororesin filler as compared with another surface side of the insulator portion facing the substrate.

7. The rotary encoder according to claim 1 , further comprising a switch mechanism that is pressed by an end portion of the shaft inserted through the encoder mechanism, and the slider is disposed so as to be positioned closer to the switch mechanism than to the insulator portion and the resistor portions.

8. The rotary encoder according to claim 1 , further comprising:
a regulating member fitted in a recess provided in the substrate; wherein
the regulating member engages an outer peripheral surface of the shaft.

9. The rotary encoder according to claim 8 , wherein
the outer peripheral surface of the shaft includes a plurality of convex portions and a plurality of concave portions alternately arranged in a circumferential direction about the shaft; and
the regulating member includes a leaf spring which engages with the plurality of convex portions and the plurality of concave portions when the shaft is rotated.

10. The rotary encoder according to claim 1 , wherein
a hole is provided in the substrate; and
the shaft is inserted through the hole of the substrate.

11. The rotary encoder according to claim 10 , wherein
the resistor portions are annularly structured and arranged concentrically; and
the resistor portions are provided on the one surface of the substrate with the resistor portions extending around the hole in a circumferential direction.

12. The rotary encoder according to claim 11 , wherein the resistor portions include at least one resistor portion provided at discontinuous intervals in the circumferential direction and one resistor portion defined by a continuous annulus which encircles the hole.

13. The rotary encoder according to claim 1 , further comprising:
encoder terminals electrically connected to respective ones of the resistor portions; wherein
the encoder terminals are at least partially embedded within the substrate.

14. The rotary encoder according to claim 1 , wherein the slider is fixed to projections defined in an upper surface of the rotor.

15. The rotary encoder according to claim 1 , further comprising electrode portions defined on the one surface of the substrate and partially covered by the insulator portion.

16. The rotary encoder according to claim 15 , wherein the resistor portions contact exposed portions of respective ones of the electrode portions through openings in the insulator portion.

17. The rotary encoder according to claim 16 , further comprising encoder terminals electrically connected to respective ones of the resistor portions through the electrode portions.

18. A method of manufacturing an encoder mechanism of a rotary encoder,
the rotary encoder including:
a shaft; and
the encoder mechanism that holds the shaft in a rotatably inserted state and detects a rotation direction and a rotation angle of the shaft; wherein
the encoder mechanism includes:
a substrate that rotatably holds the shaft;
an insulator portion and resistor portions provided on one surface of the substrate and alternately provided in the rotation direction of the shaft;
a rotor attached to the shaft so as to be integrally rotatable with the shaft; and
a slider that is attached to the rotor and alternately contacts the insulator portion and the resistor portions in a sliding manner by rotation of the shaft; and

the insulator portion includes a base material made of a resin, spherical silica, and

a fluororesin filler; and
the method comprising:
a step of preparing an insulating material including the base material made of a resin, spherical silica, and a fluororesin filler;
a step of providing an electrode portion on one surface of the substrate so as to extend in a rotation direction of the shaft;
a step of applying the insulating material on the electrode portion to form the insulator portion so that the electrode portion is exposed intermittently in a circumferential direction; and
a step of applying a resistor material on the electrode portion exposed from the insulator portion to form the resistor portions; wherein
in the step of preparing the insulating material, a second fluororesin filler having an average particle diameter of about 0.5 μm or more and about 10 μm or less, the spherical silica, and the base material are kneaded to produce a first fluororesin filler having an average particle diameter of about 50 nm or more and about 800 nm or less by crushing the second fluororesin filler.

19. A rotary encoder comprising:
a shaft; and
an encoder mechanism that holds the shaft in a rotatably inserted state and detects a rotation direction and a rotation angle of the shaft; wherein
the encoder mechanism includes:
a substrate that rotatably holds the shaft;
an insulator portion and resistor portions provided on one surface of the substrate and alternately provided in the rotation direction of the shaft;
a rotor attached to the shaft so as to be integrally rotatable with the shaft; and
a slider that is attached to the rotor and alternately contacts the insulator portion and the resistor portions in a sliding manner by rotation of the shaft;

the insulator portion includes a base material made of a resin, spherical silica, and a fluororesin filler; and
the base material is an epoxy resin.

Assignees

• Murata Manufacturing Co

Inventors

• Marusawa Hiroshi
• Nomura Yoshiaki
• Kishishita Hiroyuki
• Murata Masakazu

Classifications

• G01D5/24442 Primary

  by mounting means · CPC title

• H01H19/08

  Bases; Stationary contacts mounted thereon · CPC title

• H01H11/04

  of switch contacts · CPC title

• G01D5/16

  by varying resistance · CPC title

• H01H2300/036

  Application nanoparticles, e.g. nanotubes, integrated in switch components, e.g. contacts, the switch itself being clearly of a different scale, e.g. greater than nanoscale · CPC title