Device for measuring paths and/or positions

• US 6,989,670 B2
• Filed: 03/25/2004
• Issued: 01/24/2006
• Est. Priority Date: 09/27/2001
• Status: Active Grant

• Current Assignee: Marquardt GmbH (J U J Marquardt KG)
• Original Assignee: Marquardt GmbH (J U J Marquardt KG)
• Inventors: Tille, Dierk, Fahrländer, Klaus
• Primary Examiner(s): LEDYNH, BOT L
• Application Number:
  US10/809,258
• Publication Number:
  US 20040232907A1
• Time in Patent Office: 670 Days
• Field of Search: 324/207.13, 3242072-20724, 324/207.26, 324/173, 324/174, 324/251, 324/244, 324259-261, 338/32.R, 338/32.H
• US Class Current: 324/207.26
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

A path and/or position measuring device is provided, including a magnet and a sensor for detecting the magnetic field intensity. The magnet and/or the sensor cooperate with a movable element. The magnet is formed such that the magnetic field intensity varies along an axis of the magnet and is not constant. The relative movement between the sensor and the magnet is substantially in the direction of the axis of the magnet. The path and/or the position of the movable element can be determined based on the magnetic field intensity detected by the sensor.

Claims

1. A path/position measuring device comprising:

a magnet fixed to a movable element;

a sensor for detecting a magnetic field intensity; and

a housing having securing means for securing a printed circuit board, said printed circuit board having an integrated circuit including electronics for evaluating a signal from said sensor, and a plug-in receptacle for a connector for establishing an electrical connection to said printed circuit board arranged on said securing means;

wherein said sensor is arranged on said printed circuit board; and

wherein said magnetic field intensity varies along an axis of said magnet such that a relative movement between said sensor and said magnet substantially in the direction of said axis is brought about by means of said movable element such that the path/position of said movable element is determined based on said magnetic field intensity detected by said sensor.

2. The path/position measuring device of claim 1, wherein said sensor generates an electrical output voltage depending upon said magnetic field intensity that is substantially proportional to said magnetic field intensity detected by said sensor.

3. The device of claim 2, wherein said electrical output voltage is substantially proportional to a flux density associated with said magnetic field intensity detected by said sensor.

4. The path/position measuring device of claim 1, wherein said sensor comprises one of a Hall sensor, and a GMR sensor.

5. The device of claim 4, wherein said sensor comprises an analog-type Hall sensor.

6. The path/position measuring device of claim 1, wherein said magnet has one of a ramp-shaped and a wedge-shaped form in said direction of said axis with respect to a linear change in a height of said magnet in said direction of said axis such that a flux density variation for said magnetic field in said direction of said axis is substantially linear, and wherein an air gap between said magnet and said sensor is substantially constant along said direction of said axis.

7. The path/position measuring device of claim 1, wherein said magnet consists of polymer-bonded magnetic particles produced by injection molding.

8. The device of claim 7, wherein said polymer-bonded magnet is molded into said movable element in the manner of a two-component part.

9. The path/position measuring device of claim 1, wherein said magnet is fastened to said movable element in a manner selected from the group consisting of a latching engagement manner, a fitting engagement manner wherein said magnet is fitted into said movable element, and an integrated manner wherein said magnet is integrated into said movable element.

10. A path/position measuring device comprising:

a magnet fixed to a movable element, said movable element comprising a push rod mounted in a linearly movable manner in a housing, said push rod being articulated on a movable part at least by means of a first ball joint and said housing being arranged on a fixed part at least by means of a second ball joint; and

a sensor for detecting a magnetic field intensity;

wherein said magnetic field intensity varies along an axis of said magnet such that a relative movement between said sensor and said magnet substantially in the direction of said axis is brought about by means of said movable element such that the path/position of said movable element is determined based on said magnetic field intensity detected by said sensor.

11. The device of claim 10, wherein said axis of said magnet is aligned approximately parallel to a longitudinal axis of said push rod.

12. The device of claim 10, further comprising a plurality of fastening plates, wherein said push rod is articulated on said movable part by means of one of said fastening plates and wherein said housing is articulated on said fixed part by means of another of said fastening plates.

13. A path/position measuring device for a domestic appliance having a movable part and a fixed part, said device comprising:

a magnet fastened to a movable element; and

a sensor for detecting a magnetic field intensity;

wherein said magnetic field intensity varies along an axis of said magnet such that a relative movement between said sensor and said magnet substantially in the direction of said axis is brought about by means of said movable element such that the path/position of said movable element is determined based on said magnetic field intensity detected by said sensor, and

wherein said movable element of said device is articulated on a movable part of the domestic appliance and said sensor of said device is articulated on a fixed part of the domestic appliance.

14. The device of claim 13, wherein the movable part comprises a drum of the domestic appliance.

15. The device of claim 13, wherein the fixed part comprises a frame of the domestic appliance.

16. The device of claim 13, wherein the domestic appliance comprises one of a laundry washing machine and a laundry dryer.

17. A path/position measuring device comprising:

a magnet fixed to a movable element, said movable element comprising a push rod mounted in a linearly movable manner in a housing, said push rod being articulated on a fixed part at least by means of a first ball joint and said housing being arranged on a movable part at least by means of a second ball joint; and

a sensor for detecting a magnetic field intensity;

wherein said magnetic field intensity varies along an axis of said magnet such that a relative movement between said sensor and said magnet substantially in the direction of said axis is brought about by means of said movable element such that the path/position of said movable element is determined based on said magnetic field intensity detected by said sensor.

19. The device of claim 17, wherein said axis of said magnet is aligned approximately parallel to a longitudinal axis of said push rod.

20. The device of claim 17, further comprising a plurality of fastening plates, wherein said housing is arranged on said movable part by means of one of said fastening plates and wherein said push rod is articulated on said fixed part by means of another of said fastening plates.

18. A path/position measuring device for a domestic appliance having a movable part and a fixed part, said device comprising:

a magnet fastened to a movable element; and

a sensor for detecting a magnetic field intensity;

wherein said magnetic field intensity varies along an axis of said magnet such that a relative movement between said sensor and said magnet substantially in the direction of said axis is brought about by means of said movable element such that the path/position of said movable element is determined based on said magnetic field intensity detected by said sensor; and

wherein said movable element of said device is articulated on a fixed part of the domestic appliance and said sensor of said device is articulated on a movable part of the domestic appliance.

21. The device of claim 18, wherein the movable part comprises a drum of the domestic appliance.

22. The device of claim 18, wherein the fixed part comprises a frame of the domestic appliance.

23. The device of claim 18, wherein the domestic appliance comprises one of a laundry washing machine and a laundry dryer.