Rotational angle detecting apparatus and torque detecting apparatus

• US 6,948,385 B2
• Filed: 05/23/2003
• Issued: 09/27/2005
• Est. Priority Date: 05/23/2002
• Status: Expired due to Fees

• Current Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Original Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Inventors: Kotaka, Kenichi, Maeda, Naoki, Tokumoto, Yoshitomo, Shiba, Mahito
• Primary Examiner(s): Lefkowitz, Edward
• Assistant Examiner(s): MILLER, TAKISHA S
• Application Number:
  US10/444,899
• Publication Number:
  US 20030217607A1
• Time in Patent Office: 858 Days
• Field of Search: 738/623.28, 738/623.26, 738/623.25, 738/623.33, 738/623.34, 738/623.35, 738/620.8, 324/208, 324/207.3, 318/432, 318/488
• US Class Current: 73/862.334
• CPC Class Codes: B62D 15/0215 by measuring on the steering column
• CPC Class Codes: B62D 5/049 detecting sensor failures
• CPC Class Codes: B62D 6/10 characterised by means for sensing or determining torque
• CPC Class Codes: G01L 3/101 involving magnetic or electromagnetic means
• CPC Class Codes: G01L 3/104 involving permanent magnets
• CPC Class Codes: G01L 3/109 involving measuring phase difference of two signals or pulse trains

Abstract

One or plural rotors are coaxially provided on a first shaft and a second shaft connected with each other by a connection shaft. Plural targets are provided at each rotor. Two detecting means disposed opposite to the targets output detection signals having phases different from each other as the rotor rotates. The steering apparatus assists steering according to a steering torque applied to the first shaft detected based on the detection signals and a steering angle of the first shaft. The steering apparatus has comparing means for comparing the detection signals with each other; malfunction judging means for judging whether any one of the detecting means is malfunctioning or not on the basis of a comparison result; and notifying means for notifying a malfunction when the malfunction judging means judges that there is a malfunction and can notify the driver of a malfunction in a torque sensor when it occurs.

Claims

1. A rotational angle detecting apparatus for detecting a rotational angle of a first rotor, comprising:

first targets provided at the first rotor;

second targets provided at a second rotor rotating coaxially with the first rotor;

two sensors, disposed opposite to the first targets for outputting detection signals having phases different from each other in accordance with each position of the first targets as the first rotor rotates;

two sensors, disposed opposite to the second targets for outputting detection signals having phases different from each other in accordance with each position of the second targets as the second rotor rotates;

a calculation processing circuit capable of performing operations of;

comparing the detection signals with each other which are output from either the two sensors disposed opposite to the first target or the two sensors disposed opposite to the second target, and

judging whether any one of the sensors is malfunctioning or not on the basis of the comparison result; and

a notifying unit for notifying a malfunction when the calculation processing circuit has judged that there is a malfunction.

2. The rotational angle detecting apparatus according to claim 1, wherein the calculation processing circuit corrects detection signals outputted from either of the two sensors disposed opposite to the first target or the two sensors disposed opposite to the second target on the basis of a difference in the phases of the detection signals and compares the corrected detection signal with the other detection signal.

3. A rotational angle detecting apparatus for detecting a rotational angle of a first rotor, comprising:

first targets provided at the first rotor;

second targets provided at a second rotor rotating coaxially with the first rotor;

two sensors, disposed opposite to the first targets for outputting detection signals having phases different from each other in accordance with each position of the first targets as the first rotor rotates;

two sensors, disposed opposite to the second targets for outputting detection signals having phases different from each other in accordance with each position of the second targets as the second rotor rotates; and

a calculation processing circuit capable of performing operations of;

calculating a difference between a local maximal value and a local minimal value of each of the detection signals,

comparing the calculated differences in the respective detection signals with each other, and

judging whether any one of the sensors is malfunctioning or not on the basis of a comparison result.

4. A torque detecting apparatus for detecting a torque applied to a first shaft or a second shaft connected with the first shaft by a connection shaft, comprising:

a first rotor coaxially provided on the first shaft;

a second rotor coaxially provided on the second shaft;

first targets provided at the first rotor;

second targets provided at the second rotor;

two sensors, disposed opposite to the first targets for outputting detection signals having phases different from each other in accordance with each position of the first targets as the first rotor rotates;

two sensors, disposed opposite to the second targets for outputting detection signals having phases different from each other in accordance with each position of the second targets as the second rotor rotates;

a calculation processing circuit capable of performing operations of;

comparing the detection signals with each other which are output from either of the two sensors disposed opposite to the first target or the two sensors disposed opposite to the second target, and

judging whether any one of the sensors is malfunctioning or not on the basis of a comparison result; and

a notifying unit for notifying a malfunction when the calculation processing circuit has judged that there is a malfunction.

5. The torque detecting apparatus according to claim 4, wherein the calculation processing circuit corrects one of the detection signals outputted from either of the two sensors disposed opposite to the first target or the two sensors disposed opposite to the second target on the basis of a difference in the phases of the detection signals and compares the corrected detection signal with the other detection signal.

6. A torque detecting apparatus for detecting a torque applied to a first shaft or a second shaft connected with the first shaft by a connection shaft, comprising:

a first rotor coaxially provided on the first shaft;

a second rotor coaxially provided on the second shaft;

first targets provided at the first rotor;

second targets provided at the second rotor;

two sensors, disposed opposite to the first targets for outputting detection signals having phases different from each other in accordance with each position of the first targets as the first rotor rotates;

two sensors, disposed opposite to the second targets for outputting detection signals having phases different from each other in accordance with each position of the second targets as the second rotor rotates; and

a calculation processing circuit capable of performing operations of;

calculating a difference between a local maximal value and a local minimal value of each of the detection signals,

comparing the calculated differences in the respective detection signals with each other, and

judging whether any one of the sensors is malfunctioning or not on the basis of a comparison result.