JPS5937695Y2 - pulse generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a Huff L/S generator using a magnetic material having the Wiegand effect, which is used for proximity sensors such as rotation sensors and position sensors.

Conventional pulse generators of this type have a pickup coil wound around a magnetic material having the Wiegand effect, such as a Wiegand wire, and a permanent magnet is provided on a moving body, such as a rotating body, so that the width of the pulse generator increases as the moving body rotates. configured to apply an alternating magnetic field to the gund wire;
A pick-up coil detects the reversal of the magnetic pole that occurs when an alternating magnetic field is applied to the Wiegand wire.
It is designed to generate pulses proportional to the rotation of the moving body.

By the way, since the pulse generator having the above configuration has a characteristic in which the Wiegand wire hysteresis curve (B-H curve) changes rapidly, the pulse peak value of the output pulse almost depends on the rate of change of the external alternating magnetic field. It has the advantage of not being affected.

However, the change in the hysteresis curve is abrupt, i.e. dB
Even if /dH is large, it cannot be infinite, so if the relative displacement speed of the permanent magnet is very slow, the changing speed of the alternating magnetic field will be very slow, and the pulse wave of the output pulse will be There is a drawback that the high value decreases and a sufficient SN ratio cannot be obtained.

The present invention was made to eliminate the above-mentioned drawbacks, and even if the relative displacement speed of the permanent magnet is small, the alternating magnetic field applied to the magnetic material having the Wiegand effect becomes rapid, so that the pulse peak value changes. It is an object of the present invention to provide a pulse generator that can generate pulses that do not occur.

The present invention will be explained in detail below based on embodiments shown in the drawings.

Example ■ In Figures 1 to 4, 1 is a Wiegand wire, which is a magnetic material having the Wiegand effect, and has a double magnetic pole structure consisting of a core part with a low coercive force and a shell part with a high coercive force. .

A pickup coil 2 is wound around the outer periphery of the Wiegand wire 1 via a coil bobbin 3.

4 is a rotating shaft, and 5 is a permanent magnet rotor that is magnetized with multiple north and south poles in the circumferential direction, and is fixed to the rotating shaft 4.

The distribution state of the magnetic field H formed by the permanent magnet rotor 5 changes in a sine wave shape with respect to the rotation angle θ, as shown in FIG.

6 is a magnetic circuit forming member, which is a square hysteresis material that draws a hysteresis curve as shown in FIG. 4, such as an anisotropic 5
It is made of ONi permalloy, cold-rolled Mo permalloy, etc., and is arranged so that one end of each faces the end face of the Wiegand wire 1 and the other end of each faces the different poles of the permanent magnet rotor 5. It is arranged close to the circumferential surface of the rotor.

Next, to describe its effect, when the permanent magnet rotor 5 rotates and a magnetic field with a strength shown by Hl in FIG. One end of the forming member 6 is rapidly magnetized, and the magnetic field applied to the Wiegand wire 1 changes rapidly even if the rotational speed of the rotor 5 is small.

Therefore, the pickup coil 2 generates a pulse whose pulse height value is not affected by the rotational speed of the rotor 5.

Embodiment 2 In this embodiment shown in FIG. 5, the Wiegand wire 1 is arranged so that its longitudinal direction (axis of easy magnetization) coincides with the rotational axis direction of the permanent magnet rotor 5.

Embodiment 2 In the embodiment shown in FIG. 6, the Wiegand wire 1 is arranged in the radial direction of the permanent magnet rotor 5. In the embodiment shown in FIG.

In each of the above embodiments, the permanent magnet rotor is disk-shaped, but it may also be gear-shaped. In this case, the magnetic field formed by the permanent magnet rotor will have a trapezoidal wave shape, which will be the signature of the disk-shaped permanent magnet rotor. The dVdθ can be increased compared to a wave-like magnetic field, and the magnetic field applied to the Wiegand wire can be made more rapid.

As described above, the present invention includes a magnetic body 1 having a Wiegand effect, a permanent magnet 5 that moves relative to the magnetic body and applies an alternating magnetic field in the direction of the easy magnetization axis of the magnetic body.
a pickup coil 2 magnetically coupled to the magnetic body;
In the pulse generator, a magnetic circuit forming member 6 made of a square hysteresis material is provided between the magnetic body 1 and the permanent magnet 50, and the alternating current generated by the permanent magnet 5 is provided through the magnetic circuit forming member. A pulse generator characterized in that a magnetic field is applied to the magnetic body 1, and according to the present invention, an alternating magnetic field applied to the magnetic body that has a Wiegand effect even if the relative displacement speed of the permanent magnet is small. Since the rate of change can be increased, the following effects can be achieved.

■ Can generate pulses with constant pulse height value.

(2) When the pulse generator according to the present invention is used as a position sensor for detecting the displacement of a moving body, the displacement detection error can be reduced and the position can be detected accurately.

(2) Even if the ambient temperature changes, the strength of the magnetic field by the permanent magnet changes, and dH/dθ changes, a pulse with a constant pulse peak value can be generated.

Further, according to the present invention, since a magnetic circuit forming member is used, excellent effects such as increasing the degree of freedom in attaching the magnetic body having the Wiegand effect and the permanent magnet are exhibited.

[Brief explanation of the drawing]

The drawings all show an embodiment of the pulse generator according to the present invention, and FIG. 1 is a side sectional view showing the first embodiment of the pulse generator, and FIG. 2 is a sectional view taken along line A-A in FIG. 1. Figure, 3rd
The figure is a distribution diagram of the magnetic field H with respect to the rotation angle θ of the permanent magnet rotor, and FIG. 4 is a hysteresis curve diagram of the magnetic circuit forming member. FIG. 5 is a side sectional view showing a second embodiment of the present invention, and FIG. 6 is a front view showing a third embodiment of the present invention. 1...Magnetic material, 2...Pickup coil, 3...Coil bobbin, 4...Rotating shaft, 5...Permanent magnet rotor, 6...
A member for forming a magnetic circuit.

Claims (1)

[Scope of utility model registration request] A magnetic body 1 having a Wiegand effect, a permanent magnet 5 that moves relative to the magnetic body and applies an alternating magnetic field in the direction of the easy magnetization axis of the magnetic body, and is magnetically coupled to the magnetic body. In a pulse generator equipped with a pickup coil 2, a magnetic circuit forming member 6 made of a square hysteresis material is provided between the magnetic body 1 and the permanent magnet 5, and the permanent magnet is connected to the permanent magnet via the magnetic circuit forming member. A HARLES generator characterized in that an alternating magnetic field of 5 is applied to the magnetic body 1.