Target design for geartooth sensor with minimal number of unique segments combined in nonrepeating fashion

• US 6,172,500 B1
• Filed: 06/23/1998
• Issued: 01/09/2001
• Est. Priority Date: 06/23/1998
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Bicking, Robert E.
• Primary Examiner(s): Snow, Walter E.
• Application Number:
  US09/103,047
• Time in Patent Office: 931 Days
• Field of Search: 324/207.22, 324/207.24, 324/207.25, 324/173, 324/174, 341/6, 341/15, 123/617, 123/406.58, 123/406.59, 123/406.63
• US Class Current: 324/207.22
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02P 7/0775 Electronical verniers
• CPC Class Codes: G01D 5/2495 Pseudo-random code

Abstract

A geartooth target providing a consistent magnetic signal for each feature type with unambiguously readable features has three unique 30° segments, each segment ending with a falling edge transition, the segments placed to have a unique pattern of segments every 90°.

Claims

1. A target design for a geartooth sensor comprising:

(a) a first segment of x degrees where x=360÷

the number of timing signals desired;

(b) a second segment of x degrees;

(c) a third segment of x degrees;

(d) each of the first, second, and third segments having a transition edge at the end of the segment; and

(e) each segment having a unique tooth-to-slot feature configuration.

2. The target design according to claim 1 wherein:

the segments are arranged such that each three segment series pattern on the target is unique.

3. The target design according to claim 1 wherein:

on the target there is a large feature size and a small feature size.

4. The target according to claim 3 wherein:

there is only a large feature size and a small feature size.

5. The target according to claim 3 wherein:

the small feature size is determined by the formula;

$\frac{360\times <br><br>\mathrm{minimum}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{slot}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{size}}{\mathrm{target}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{diameter}\times <br><br>\mathrm{\pi <br><br>}}$

6. The target according to claim 3 wherein:

the large size features are at least two times the angular size of the small features.

7. The target according to claim 3 wherein:

the small feature size is greater than or equal to 10 millimeters at the outer edge of the features.

8. The target according to claim 6 wherein:

the small features are 7.5 degrees and the large features are 22.5 degrees.

9. The target according to claim 3 wherein:

the target diameter is approximately 160 millimeters and the minimum feature size is 7.5 degrees.

10. The target according to claim 3 wherein:

the first segment is comprised of interspersed small slots and small teeth.

11. The target according to claim 3 wherein:

the second segment is comprised of one small feature and one large feature, the features being of opposite type.

12. The target according to claim 3 wherein:

the third segment is the complementary image of the second segment.

13. The target according to claim 10 wherein:

the third segment is the complementary image of the second segment.

14. The target design according to claim 1 wherein:

the transition edge at the end of each segment is a tooth-to-slot edge.

15. A target design for a geartooth sensor comprising:

(a) a first segment A of 30 degrees;

(b) a second segment B of 30 degrees;

(c) a third segment C of 30 degrees;

(d) each segment having a transition edge at the end of the segment;

(e) each segment having a unique configuration of features;

(f) the features being selected from the group comprising small teeth, small slot, large teeth, large slot;

(g) the segments arranged about the circumference of the target so that every three segment set is a unique pattern of features.

16. The target design according to claim 15 wherein:

on the target there is a large feature size and a small feature size.

17. The target design according to claim 16 wherein:

there is only a large feature size and a small feature size.

18. The target according to claim 15 wherein:

the large size features are about three times the angular size of the small features.

19. The target design according to claim 15, wherein:

the transition edge at the end of each segment is a tooth-to-slot edge.