Magnetic type angle sensor

• US 7,400,141 B2
• Filed: 02/22/2007
• Issued: 07/15/2008
• Est. Priority Date: 06/24/2004
• Status: Active Grant

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Nagatomo, Ichirou, Imai, Keisuke, Taniguchi, Mitsuyuki
• Primary Examiner(s): Assouad; Patrick
• Assistant Examiner(s): Schindler; David M.
• Application Number:
  US11/709,248
• Publication Number:
  US 20070152661A1
• Time in Patent Office: 509 Days
• Field of Search: 324/207.22, 324/207.25, 298/933, 298/933.5, 409/10, 409/15
• US Class Current: 324/207.25
• CPC Class Codes: G01D 5/2457 Incremental encoders having reference marks
• CPC Class Codes: Y10T 29/49467 Gear shaping
• CPC Class Codes: Y10T 29/49476 Gear tooth cutting
• CPC Class Codes: Y10T 409/101431 Gear tooth shape generating
• CPC Class Codes: Y10T 409/102226 with control means energized in response to activator stimulated by condition sensor

Abstract

A magnetic type angle sensor includes a rotary body having a first sensed part provided on a circumferential surface thereof with projecting parts and recessed parts at equal intervals in a circumferential direction thereof and a second sensed part provided on a circumferential surface thereof with a projecting parts at just one location, and a magnetic sensing device for sensing a change in a magnetic field along with rotation of the rotary body. The rotary body is formed with a plurality of projecting parts and recessed parts in a gear shape by gear cutting on the circumferential surface, then is cut with a groove at the center thereof in the axial direction thereof and has all projecting parts in a half section in the axial direction thereof cut off except for one.

Claims

1. A method of producing a magnetic type angle sensor, said magnetic type angle sensor comprising a rotary body and a magnetic sensing device arranged facing said rotary body and sensing a change in a magnetic field along with rotation of said rotary body, said rotary body including a first sensed part provided on a circumferential surface thereof with a plurality of recessed parts and projecting parts alternately at equal intervals in a circumferential direction thereof and a second sensed part provided on the circumferential surface thereof with a projecting part at only one location, said method comprising the steps of:

providing a gear-shaped member including a first portion to be formed into said first sensed part and a second portion to be formed into said second sensed part;

forming an annular groove on the circumferential surface of said gear-shaped member between said first portion and said second portion; and

forming said second sensed part by removing all of the projecting parts except at one location from the second portion.