Rotation detection device

Abstract

The rotation detection device capable of accurately detecting the rotational direction even when the intervals of the plurality of detection objects in the rotating body vary, especially when such a rotating body rotates at a high speed, includes: first to Nth sensor elements, Opposite to the rotating body rotatable in the forward rotation direction and the reverse rotation direction, and are arranged side by side in order along the rotatable direction, and respectively output the first to Nth (N≥3) sensor signals according to the rotation of the rotating body; The direction detection unit detects the rotation direction of the rotating body based on the respective sensor signals output from the respective sensor elements; the rotation direction detection unit is based on the first differential signal obtained from the first sensor signal and the Mth (3≤M≤N) sensor signal. , and a second differential signal obtained from the first sensor signal and the Lth (2≤L≤M-1) sensor signal to detect the rotational direction of the rotating body.

Description

technical field [0001] The present invention relates to a rotation detecting device for detecting the rotation state of a rotating body. Background technique [0002] Conventionally, a rotation detection device for detecting a rotation state such as a rotation position, a rotation speed, and a rotation direction of a rotating body has been used for various purposes. As such a rotation detection device, a rotation detection device including a rotating body such as a multi-pole magnetized magnet having gears and a plurality of N poles and S poles arranged alternately in the circumferential direction, and a magnetic sensor arranged to face the rotating body is known. , the gear has a plurality of teeth made of magnetic material, and the magnetic sensor detects a change in the direction of the magnetic field accompanying the rotation of the rotating body and outputs a signal representing the relative positional relationship between the rotating body and the magnetic sensor. [...

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Problems solved by technology

[0009] However, in a magnetized rotor in which a plurality of N poles and S poles are alternately arranged, since the distance between two adjacent N poles (or two S poles) varies, even three magnetic sensor elements Arranged with high-precision positioning, noise also increases depending on the magnetization accuracy in the magnetized rotor, and the noise resistance cannot be improved, so there is a problem that errors are included in the information related to the obtained rotation state.

[0010] In addition, since the detection of the rotation direction is performed based on the differential output of two adjacent magnetic sensor elements, when the rotating body rotates at a high speed, there is a possibility that the differential outputs whose phases are shifted from each other may overlap, and the detection of the rotation direction may not be possible. become extremely difficult

[0011] Also, even when a gear having a plurality of teeth is used as a rotating body, the interval between two adjacent teeth varies, so the same problem as above occurs.

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