motor

Abstract

Provided is a motor capable of detecting rotation of a shaft with high precision by suppressing cogging in a rotation detection device. In the rotation detection device (1) installed on the motor (210), the first support body (11) on which the magnets (21, 22) etc. During rotation of the second support body (12) such as (31), the magnetic field formed by the magnets (21, 22) etc. is detected by the magnetic field detector (31) etc., thereby detecting the rotation state of the shaft (213). One end and the other end of each magnetic field detection unit (31) and the like are covered with magnetic members (41, 42) and the like. Each pair of magnetic components (41-46) faces each other with a gap (S1) in the middle part of each magnetic field detection part (31-33) in the longitudinal direction, and the dimension of each magnet (21-24) in the tangential direction of the circumference ( D1) is greater than its radial dimension (D4), and is greater than the distance of the gap (S1).

Description

technical field [0001] The present invention relates to a motor having a rotation detection device that detects rotation of a shaft using magnetism. Background technique [0002] A rotation detection device that is usually attached to a motor and generates a pulse signal corresponding to the rotation of the shaft of the motor using magnetism has been used. [0003] As a conventional rotation detecting device, there is known a device that is configured to sandwich at least two magnetic elements capable of causing a large Barkhausen jump, a coil wound around each magnetic element, and sandwich the magnetic elements. The element is composed of a pair of permanent magnets whose magnetic pole directions are opposite to each other, and detects the rotation of a gear having a plurality of teeth made of magnetic material (for example, refer to Patent Document 1). [0004] In this rotation detection device, since the pair of permanent magnets are arranged with a space smaller than t...

AI Technical Summary

Problems solved by technology

[0008] There is such a problem that due to the generation of cogging torque, the rotation speed of the gear fluctuates (cogging occurs), and it is transmitted to the rotating shaft of the gear to cause vibration and noise, and it acts like a static torque. Increase the starting torque of the gear

Therefore, in a motor equipped with such a rotation detection device, there is a problem that the rotation of the shaft cannot be detected with high precision by the rotation detection device.

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