Title:
ROTATIONAL SPEED DETECTING DEVICE AND ROTATIONAL SPEED DETECTING METHOD
Document Type and Number:
WIPO Patent Application WO/2018/105692
Kind Code:
A1
Abstract:
Provided are a rotational speed detecting device and a rotational speed detecting method which enable accurate detection of the rotational speed of a rotating shaft over a wide detection range, using a simple, compact, inexpensive configuration that does not require a hole to be formed in a casing accommodating the rotating shaft. This rotational speed detecting device is provided with: a magnet which is mounted on a rotating shaft to be detected, and which has at least one N pole and one S pole, magnetized in a direction orthogonal to the axial direction of the rotating shaft; a sensor body which has a plate-shaped magnetic core comprising a soft magnetic body, wherein a central portion, in the longitudinal direction, of the magnetic core is narrower than the two end portions thereof, and a coil is wound around the central portion; an alternating-current power source which applies an alternating current to the coil; and a voltage detecting portion which detects variations in a voltage generated between the two ends of the coil. The applied magnetic field with which magnetic saturation of the central portion of the magnetic core begins is set to be at least equal to 1/10 and at most equal to 1/2 of the maximum value of the magnetic field generated from the magnet at the position of the sensor body.
Inventors:
KAWAKAMI MAKOTO (JP)
ABE YASUNORI (JP)
ABE YASUNORI (JP)
Application Number:
PCT/JP2017/043998
Publication Date:
June 14, 2018
Filing Date:
December 07, 2017
Export Citation:
Assignee:
HITACHI METALS LTD (JP)
International Classes:
G01P3/487
Foreign References:
| EP1950525A1 | 2008-07-30 | |||
| JPH0792179A | 1995-04-07 | |||
| JPH03123815A | 1991-05-27 | |||
| JPS472172U | 1972-08-24 |
Attorney, Agent or Firm:
KOHNO, Hideto et al. (JP)
Download PDF: