Combination hall effect position sensor and switch

• US 6,992,478 B2
• Filed: 12/22/2003
• Issued: 01/31/2006
• Est. Priority Date: 12/22/2003
• Status: Active Grant

• Current Assignee: CTS Corporation
• Original Assignee: CTS Corporation
• Inventors: Jarrard, Craig, Etherington, Kurt
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US10/743,176
• Publication Number:
  US 20050134257A1
• Time in Patent Office: 771 Days
• Field of Search: 32420711-20726, 324242-244, 324/247, 324/249, 324/251, 324/252, 324/260, 324173-174, 280/735, 123/612, 123/617
• US Class Current: 324/207.2
• CPC Class Codes: G01D 2205/775 Tapered profiles
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A combination Hall effect position sensor and switch for sensing the position of a moveable object. The sensor has a magnet that is attachable to the moveable object. The magnet has a pair of ends and a central portion. A linear magnetic flux sensor is positioned about the central portion of the magnet. The linear magnetic flux sensor generates an electrical signal indicative of a specific position of the movable object. A switch type magnetic flux sensor is positioned about one of the ends of the magnet. The switch type magnetic flux sensor generates an electrical signal that is indicative of the movable object reaching a pre-determined location.

Claims

1. A sensor for sensing position of a moveable object, comprising:

a magnet attachable to the object, the magnet having a pair of ends and a central portion, the magnet generating a slowly changing flux field near the central portion and a rapidly changing flux field at the ends;

a first magnetic flux sensor positioned about the central portion of the magnet, the first magnetic flux sensor generating an electrical signal indicative of a specific position of the movable object; and

a second magnetic flux sensor positioned about the first end of the magnet, the second magnetic flux sensor generating an electrical signal indicative of when the movable object has reached a pre-determined location.

2. The sensor according to claim 1 wherein, the first and second magnetic flux sensors are hall effect devices.

3. A sensor for sensing movement of a movable object, comprising:

a) at least one magnet attachable to the movable object, the magnet having a first end, a second end and a central portion;

b) the first and second ends of the magnet having a first flux density that changes about the ends;

c) the central portion of the magnet having a second flux density that changes more slowly about the central portion than about the ends of the magnet;

d) a first magnetic flux sensor positioned about the central portion of the magnet, the first magnetic flux sensor generating a first electrical signal indicative of a specific position of the movable object; and

e) a second magnetic flux sensor positioned about the first end of the magnet, the second magnetic flux sensor generating a second electrical signal indicative of the movable object reaching a pre-determined location.

4. The sensor according to claim 3 wherein, the second magnetic flux sensor functions as a first switch.

5. The sensor according to claim 3 wherein, a third magnetic flux sensor is positioned about the second end.

6. The sensor according to claim 5 wherein, the third magnetic flux sensor functions as a second switch.

7. The sensor according to claim 3 wherein, the first electrical signal is linear.

8. The sensor according to claim 3 wherein, the second electrical signal is step shaped.