Angle encoder with four hall sensors and method for angle determination of output signals of the four hall sensors

• US 6,479,987 B1
• Filed: 12/14/1999
• Issued: 11/12/2002
• Est. Priority Date: 04/18/1998
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Marx, Klaus, Jost, Franz
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): Aurora, Reena
• Application Number:
  US09/445,879
• Time in Patent Office: 1,064 Days
• Field of Search: 324/207.2, 324/207.25, 324/251, 324/207.12, 338/32.H
• US Class Current: 324/207.2
• CPC Class Codes: G01B 7/30 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

An angle encoder for determination of an angle between a sensor device (4, 5, 6, 7) and a magnetic field, having a magnet (2) that generates the magnetic field, a number of Hall elements (4, 5, 6, 7) disposed in the magnetic field, and flux-conducting parts (3) made of ferromagnetic material disposed between the Hall elements and rotationally fixed in relation to them, wherein the magnet (2) is embodied so that it can rotate in relation to the Hall elements and the flux-conducting parts, wherein at least four Hall elements (4, 5, 6, 7) are provided.

Claims

1. A method for angle determination of an angle between a sensor device and a magnetic field through the use of an angle encoder having a magnet (2) that generates the magnetic field, a number of Hall elements (4, 5, 6, 7) disposed in the magneticfield, and flux-conducting parts (3) made of ferromagnetic material disposed between the Hall elements and rotationally fixed in relation to the latter, wherein the magnet (2) is embodied so that it can rotate in relation to the Hall elements and the flux-conducting parts, wherein at least four Hall elements (4, 5, 6, 7) are provided and wherein the magnet (2) has a diametrical magnetization, the method comprising the steps:

alignment of the magnet (2) in such a way that a Hall voltage respectively induced in at least two Hall elements (4, 6) is proportional to the sine of the angle between a reference direction and a field direction produced by the magnet and that a Hall voltage respectively induced in at least two Hall elements (5, 7) is proportional to the cosine of the angle between the reference direction and the field direction produced by the magnet,

measurement of the Hall voltages in the respective Hall elements (4, 6, 5, 7)

arithmetical determination of the angle to be determined through the use of the four Hall voltages measured, whereby a sum signal is respectively formed from said at least two Hall voltages in Hall elements (4, 6), which voltages are proportional to the sine of the angle to be determined, and from said at least two Hall voltages in Hall elements (5, 7) which voltages are proportional to the cosine of the angle to be determined, and whereby the sum signals thus obtained are supplied to a sine-cosine evaluation circuit for arithmetical determination of the angle to be determined.

2. The method according to claim 1, characterized in that the arithmetical determination of the angle to be determined is carried out based on the signals that are respectively proportional to the sine or cosine of the angle, by means of a determination of an associated arc tangent.

3. A method for angle determination of an angle between a sensor device and a magnetic field through the use of an angle encoder having a magnet (2) that generates the magnetic field, a number of Hall elements (4, 5, 6, 7) disposed in the magnetic field, and flux-conducting parts (3) made of ferromagnetic material disposed between the Hall elements and rotationally fixed in relation to the latter, wherein the magnet (2) is embodied so that it can rotate in relation to the Hall elements and the flux-conducting parts, wherein at least four Hall elements (4, 5 ,6, 7) are provided and wherein the magnet (2) has a diametrical magnetization, the method comprising the steps:

alignment of the magnet (2) in such a way that a Hall voltage respectively induced in at least two Hall elements (4, 6) is proportional to the sine value of the angle between a reference direction and a field direction produced by the magnet and that a Hall voltage respectively induced in at least two Hall elements (5, 7) is proportional to the cosine value of the angle between the reference direction and the field direction produced by the magnet,

measurement of the Hall voltages in the respective Hall elements (4, 6, 5, 7),

arithmetical determination of the angle to be determined through the use of the four Hall voltages measured, whereby for at least two pairs of Hall elements (4, 5, 6, 7), the one of which has a Hall voltage proportional to the sine of the angle to be determined and the other of which has a Hall voltage proportional to the cosine of the angle to be determined, the angle to be determined is arithmetically determined by means of a sine-cosine evaluation circuit, and whereby the average from the two values determined for the angle to be determined is calculated.

4. The method according to claim 3, characterized in that the arithmetical determination of the angle to be determined is carried out based on the signals that are respectively proportional to the sine or cosine of the angle, by means of a determination of an associated arc tangent.