Bearing with absolute angel sensor

• US 20090102466A1
• Filed: 08/03/2004
• Published: 04/23/2009
• Est. Priority Date: 08/03/2004
• Status: Active Grant

• Current Assignee: NTN Corporation
• Original Assignee: NTN Corporation
• Inventors: Yamada, Koji
• Granted Patent: US 8,212,551 B2
• Time in Patent Office: Days
• US Class Current: 324/207.250
• CPC Class Codes: F16C 19/52 with devices affected by abnormal or undesired conditions
• CPC Class Codes: G01D 18/001 Calibrating encoders
• CPC Class Codes: G01D 5/2449 using hard-stored calibration data
• CPC Class Codes: G01P 3/443 mounted in bearings bearings F16C

Abstract

To provide a rotation sensor equipped bearing capable of detecting a highly precise absolute angle with no correction work required after incorporation into a bearing installed equipment, an absolute angle sensor equipped bearing assembly includes a sensor equipped bearing 1 and a correction data storing device 20. The sensor equipped bearing 1 has a rotation detector 6 capable of providing, as a detection output indicative of the rotation angle of a rotating raceway ring relative to a stationary raceway ring, two analog outputs X and Y that are offset 90° in phase relative to each other in terms of electrical degree. The correction data storing device 20 stores a correction data for correcting an error when the absolute angle of the rotation angle of the rotating raceway ring is calculated from the two analog outputs X and Y and which is used pared with the sensor equipped bearing 1.

Claims

1. An absolute angle sensor equipped bearing assembly comprising:

a sensor equipped bearing having a rotation detector capable of providing, as a detection output indicative of a rotation angle of a rotating raceway ring relative to a stationary raceway ring, two analog outputs that are offset 90°

in phase relative to each other in terms of electrical degree; and

a correction data storing device, which stores a correction data for correcting an error when an absolute angle of the rotation angle of the rotating raceway ring is calculated based on the two analog outputs, and which is used paired with the sensor equipped bearing.

2. The absolute angle sensor equipped bearing assembly as claimed in claim 1, wherein the rotation detector includes a to-be-detected element fitted to the rotating raceway ring and having a magnetic characteristic cyclically varying in a circumferential direction, and two magnetic sensors fitted to the stationary raceway ring in face-to-face relation with the to-be-detected element and capable of providing respective analog outputs offset 90°

in phase relative to each other in terms of electrical degree.

3. The absolute angle sensor equipped bearing assembly as claimed in claim 1, wherein the correction data storing device includes a correction table, storing the correction data, and an absolute angle calculating section, which utilizes the correction table to calculate the absolute angle based on the two analog outputs, and wherein the correction data referred to above is based on an angle correction data measured after the manufacture of the sensor equipped bearing.

4. The absolute angle sensor equipped bearing assembly as claimed in claim 1, wherein the correction data is integrated with an angle value, which provides a result of calculation of an inverse arc tangent in an inverse arc tangent calculation table.

5. The absolute angle sensor equipped bearing assembly as claimed in claim 1, wherein the correction data storing device is a one-chip type microcomputer, a programmable logic circuit or a circuit board having the one-chip microcomputer or the programmable logic circuit mounted thereon.