Rotation angle detector and bearing with rotation angle detector

• US 7,884,600 B2
• Filed: 11/30/2006
• Issued: 02/08/2011
• Est. Priority Date: 01/06/2006
• Status: Expired due to Fees

• Current Assignee: NTN Corporation
• Original Assignee: NTN Corporation
• Inventors: Takahashi, Toru
• Primary Examiner(s): Patidar; Jay M
• Application Number:
  US12/087,417
• Publication Number:
  US 20090072819A1
• Time in Patent Office: 1,531 Days
• Field of Search: None
• US Class Current: 324/207.25
• CPC Class Codes: F16C 19/06 with a single row or balls
• CPC Class Codes: F16C 33/723 Shaft end sealing means, e.g. cup-shaped caps or covers
• CPC Class Codes: F16C 41/007 Encoders, e.g. parts with a plurality of alternating magnetic poles
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06

Abstract

To provide a rotation angle detecting device, in which undesirable noises from an angle calculating circuit can be reduced to increase a detection accuracy, outputs of four linear magnetic sensor arrays arranged on a non-rotatable member confronting a magnetic generating element and arranged in a plane perpendicular to the axis of rotation, the sensor arrays being arranged along four sides of an imaginary rectangular shape, are read out by signal read-out circuits, and then converted into digital signals by AD converting circuits in order to calculate an angle of rotation of the magnetic generating element by an angle calculating circuit. The signal read-out circuits and the AD converter circuits are arranged outside of the magnetic sensor arrays arranged in a generally rectangular pattern, and the angle calculating circuit is arranged inside of the magnetic sensor arrays, all being mounted on a semiconductor chip.

Claims

1. A rotation angle detecting device which comprises:

a magnetic generating element arranged on a rotatable member and having a magnetic anisotropy in a circumferential direction about the axis of rotation;

four linear magnetic sensor arrays arranged on a non-rotatable member confronting the magnetic generating element in a direction along the axis of rotation and arranged in a plane perpendicular to the axis of rotation, each of the sensor arrays being arranged along one of four sides of an imaginary rectangular shape;

a signal read-out circuit for reading respective outputs of the four magnetic sensor arrays;

an AD converting circuit for converting each of the signals so read out into a respective digital signal; and

an angle calculating circuit for calculating the angle of rotation of the magnetic generating element from an output of the AD converting circuit,

wherein the magnetic sensor arrays, the signal read-out circuit, the AD converting circuit and the angle calculating circuit are all mounted on one semiconductor chip, the signal read-out circuit and the AD converting circuit are arranged outside the magnetic sensor arrays arranged in a generally rectangular pattern, and the angle calculating circuit is arranged inside the magnetic sensor arrays arranged in a generally rectangular pattern.

2. The rotation angle detecting device as claimed in claim 1, wherein an outer periphery of the angle calculating circuit is surrounded by a shield pattern so that a gap area between the magnetic sensor arrays and the angle calculating circuit is formed as a digital noise shielding area.

3. The rotation angle detecting device as claimed in claim 1, wherein each of the magnetic sensor array is divided into two magnetic sensor element sets and is associated with two signal processing circuits, each of which includes the signal read-out circuit and the AD converting circuit and corresponds to each of the two magnetic element sets, so that the two signal processing circuits simultaneously read out signals from respective magnetic element sets.

4. The rotation angle detecting device as claimed in claim 3, wherein the two signal processing circuits are so associated with each of the magnetic sensor arrays as to read out from the magnetic sensor element sets corresponding respectively to opposite end portions into which the magnetic sensor array is divided in a direction lengthwise thereof.

5. The rotation angle detecting device as claimed in claim 3, wherein the two signal processing circuits associated with each of the magnetic sensor arrays include respective signal read-out circuits for reading out and amplifying an output from the magnetic sensor array, and the AD converting circuit for converting an output of the signal read-out circuit into a digital signal is commonly utilized by the two signal processing circuits.

6. The rotation angle detecting device as claimed in claim 1, further comprising four auxiliary magnetic sensor arrays, each of which is arranged outside respective four corners of the rectangular shape depicted by the four magnetic sensor arrays.

7. The rotation angle detecting device as claimed in claim 6, wherein the signal read-out circuit and the AD converting circuit for converting a read-out signal therefrom into a digital signal, which is in turn supplied to the angle calculating circuit, are provided for each of the auxiliary sensor arrays arranged outside the four corners of the rectangular shape.

8. A rotation angle detecting device equipped bearing assembly equipped with the rotation angle detecting device as defined in claim 1.