Linear encoding device with staggered detectors

• US 6,100,681 A
• Filed: 08/03/1998
• Issued: 08/08/2000
• Est. Priority Date: 08/06/1997
• Status: Expired due to Term

• Current Assignee: Nippon Thompson Company Limited
• Original Assignee: Nippon Thompson Company Limited
• Inventors: Tsuruta, Naohito
• Primary Examiner(s): STRECKER, GERARD R
• Application Number:
  US09/127,904
• Time in Patent Office: 736 Days
• Field of Search: 324/207.2, 324/207.21, 324/207.24, 324/165, 324/173, 324/174, 310/12, 318/135, 341/15
• US Class Current: 324/207.2
• CPC Class Codes: F16C 29/008 Systems with a plurality of bearings, e.g. four carriages supporting a slide on two parallel rails
• CPC Class Codes: F16C 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01B 7/023 for measuring distance between sensor and object G01B7/082 and G01B7/102 take precedence
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01D 5/2451 Incremental encoders G01D5/2454 takes precedence
• 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

Abstract

Onto a long rectangular board like base board, first Hall IC'"'"'s are mounted at specified equal pitches in the longitudinal direction, and second Hall IC'"'"'s are mounted at the equal pitches from a position shifted by a phase difference of 90 degrees in the longitudinal direction relative to this first Hall IC, and a single rectangular board like field magnet (12) having a length of a half of the equal pitch is mounted, opposite to the first Hall IC'"'"'s and the second hole IC'"'"'s, and consequently, a linear encoding device is provided, by which a long positional measurement can be performed, and further, which has a simple arrangement.

Claims

1. A linear encoding device of a guiding device including a long base stand and a table slidably guided along a longitudinal direction of said base stand,

the linear encoding device comprising a detected element mounted to said table and a detecting element mounted to said base stand, wherein:

said detecting element comprises a plurality of Hall IC'"'"'s;

said Hall IC'"'"'s comprise first Hall IC'"'"'s arranged at equal pitches in said longitudinal direction and second Hall IC'"'"'s arranged at said equal pitches in line or in parallel with said first Hall IC'"'"'s, the second Hall IC'"'"'s being shifted in the longitudinal direction by a quarter of said pitch relative to said first hall IC'"'"'s, corresponding to a phase difference of 90 degrees to said first Hall IC'"'"'s in said longitudinal direction;

said detected element comprises a rectangular board-like field magnet wherein a single magnetic pole thereof faces toward said Hall IC'"'"'s, and having a length of a half of said pitch corresponding to a phase of 180 degrees, whereby

said Hall IC'"'"'s detect said field magnet and output signals of a phase A corresponding to the first Hall IC'"'"'s and a phase B corresponding to the second Hall IC'"'"'s.

2. The linear encoding device according to claim 1, wherein said Hall IC'"'"'s are mounted onto said base stand through a base board.

3. The linear encoding device according to claim 1, wherein said pitch is approximately from 8 mm to 40 mm.

4. The linear encoding device, according to claim 1 wherein said guiding device includes a linear motor table comprising:

a long rectangular board like bed;

a slidable table which is guided by a linear motion rolling guiding unit along the longitudinal direction of said bed; and

a movable magnet linear electromagnetic actuator which drives said table in such a way that sliding and positioning are free, relative to the bed.