JPH06160499A - Magnetic detector - Google Patents

Abstract

PURPOSE:To improve a detecting sensitivity of a magnetic field by mounting magnetic circuits each having a member of high permeability at both ends of a magnetic sensor, efficiently gathering magnetic fluxes and inputting them to the sensor. CONSTITUTION:A magnetic sensor 1 uses, for example, a Hall element. Connecting leads 5 are connected to electrodes provided on upper and lower surfaces, a voltage is applied between the leads 5 to supply a current to the element. Magnetic circuits 2, 3 are formed of a material having large permeability such as a silicon steel plate or ferrite, and mounted substantially in a U shape at both ends of the element. Magnetic fluxes are efficiently gathered to the element to be input. Output connecting leads 4 are connected to electrodes provided on an opposite surface to the surface of this side of the element to output a Hall voltage proportional to the current and the magnetic flux from between the leads 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detection device. 2. Description of the Related Art In recent years, magnetic detection devices have been widely used in OA devices and the like including electronic devices in order to detect and control displacement of mechanical parts, moving speed, and the like using a magnetic field as a medium.

[0002]

2. Description of the Related Art In a conventional magnetic detection device, as shown in FIG. 3, magnetic bodies 6 which are alternately magnetized to have N poles and S poles are attached to the surface of a moving body. The magnetic sensor 9 is disposed facing the magnetic sensor 9, the magnetic flux of the magnetic body 6 passing the magnetic sensor 9 is detected by the magnetic sensor 9, converted into an electric signal and output, and based on the output, displacement of the moving body, The moving speed was controlled.

[0003]

Conventionally, the magnetic sensor 9 has been used.
A plurality of sensors are provided in parallel so that even a low magnetic field can be detected, and the magnetic field detection sensitivity is increased. Therefore,
Since a plurality of magnetic sensors are connected and used, there is a problem that the cost becomes high. It is an object of the present invention to efficiently input a magnetic flux to a magnetic sensor by using a high magnetic permeability member, suppress an increase in cost, and improve magnetic field detection sensitivity.

[0004]

As shown in FIG. 1, magnetic circuits 2 and 3 made of high-permeability members are attached to both ends of a magnetic sensor 1 in a substantially U shape so that the efficiency of the magnetic circuits 2 and 3 is increased. The magnetic flux is well collected and input to the magnetic sensor 1.

[0005]

As described above, according to the present invention, the magnetic circuits 2 and 3 having a large magnetic permeability are used, and the magnetic flux can be efficiently collected and input to the magnetic sensor 1. Therefore, the magnetic field detection sensitivity can be improved. Is possible.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a magnetic detection device showing an embodiment of the present invention. 1 is a magnetic sensor, for example,
A Hall element is used, the connection leads 5 are connected to the electrode portions provided on the upper surface and the lower surface, a voltage is applied between the connection leads 5, and a current Ia is passed through the Hall element. 2 and 3 are magnetic circuits, which have a large magnetic permeability,
For example, a silicon steel plate or ferrite is used and is attached to both ends of the hall element in a substantially U-shape so that the magnetic flux B is efficiently collected and input to the hall element. Reference numeral 4 denotes a connection lead for output, which is connected to an electrode portion provided on the surface opposite to the front surface of the Hall element, and from between the connection leads 4, a Hall voltage proportional to the current Ia and the magnetic flux B. I'm trying to take out.

FIGS. 2A and 2B are explanatory views showing the arrangement state of the above magnetic detecting device. In the figure, the same components as those shown in FIG. 1 are designated by the same symbols. . Reference numeral 6 denotes a magnetic body, which is magnetized so as to alternately have N poles and S poles, and the magnetic detection device of the present invention is arranged so as to face the magnetic body 6. In FIG. 1A, the magnetic circuit 3 is located substantially in the center of the N pole of the magnetic body 6, and the magnetic circuit 2 is located in the magnetic body 6.
Since the magnetic flux from the N pole is located almost in the center of the S pole and enters the S pole through the magnetic circuit 3, the Hall element, and the magnetic circuit 2, the Hall voltage can be extracted from the Hall element. In the diagram (B), the magnetic circuit 3 is located at the boundary between the N pole and the S pole of the magnetic body 6, and the magnetic circuit 2 is located at the N pole and the S pole of the magnetic body 6.
The Hall element is located at the boundary of the poles, and since the magnetic flux in the same direction is directed to the magnetic circuit 3 and the magnetic circuit 2, the magnetic flux is not input to the Hall element, and therefore the Hall element does not output the Hall voltage.

Therefore, for example, the magnetic body 6 is attached to the surface of the moving body, the magnetic detection device of the present invention is arranged facing the magnetic body 6, and the magnetic flux of the magnetic body 6 passing over the magnetic sensor 1 is detected by the magnetic sensor. When the Hall element is used as the magnetic sensor 1 in step 1, the displacement of the moving body, the moving speed, etc. can be controlled by extracting the Hall voltage as a high level voltage or a low level voltage. When a magnetoresistive element is used as the magnetic sensor 1, a change in resistance value of the magnetoresistive element, which changes due to a magnetic flux passing through the magnetoresistive element, is detected between the connecting leads 4 or between the connecting leads 5 and converted into an electric signal. Then, the displacement of the moving body, the moving speed, etc. are controlled based on the electric signal. As magnetic circuits 2 and 3,
Since a material having a large magnetic permeability, such as a silicon steel plate or ferrite, is used, the magnetic flux can be collected more efficiently than the case where only the magnetic sensor 9 is arranged facing the magnetic body 6 as in the conventional example of FIG. Can be input to the magnetic sensor 1 and the magnetic field detection sensitivity can be increased. Therefore, it is possible to suppress the cost increase as compared with the conventional case where a plurality of magnetic sensors are connected to increase the magnetic field detection sensitivity.

[0009]

As described above, according to the present invention, since the magnetic circuits 2 and 3 made of a material having a large magnetic permeability are used for the magnetic sensor 1, the magnetic flux can be efficiently collected to generate a magnetic field. It is possible to provide a magnetic detection device that can be input to the sensor 1 and that suppresses an increase in cost and improves magnetic field detection sensitivity as compared with the conventional example.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic detection device showing an embodiment of the present invention.

FIG. 2A and FIG. 2B are explanatory views showing an arrangement state of the magnetic detection device of the above.

FIG. 3 is an explanatory view showing an arrangement state of a magnetic detection device showing a conventional example.

[Explanation of symbols]

 1 Magnetic Sensor 2 Magnetic Circuit 3 Magnetic Circuit 4 Connection Lead 5 Connection Lead 6 Magnetic Material 9 Magnetic Sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G01R 33/06 H 8203-2G H01L 43/06 Z 9274-4M

Claims (4)

[Claims] 1. A magnetic detection device comprising high permeability members provided at both ends of a magnetic sensor. 2. The magnetic detection device according to claim 1, wherein the magnetic sensor is a Hall element. 3. The magnetic detection device according to claim 1, wherein the magnetic sensor is a magnetoresistive element. 4. The magnetic detection device according to claim 1, wherein the high magnetic permeability member is made of a silicon steel plate or the like, and is attached to both ends of the magnetic sensor in a substantially U shape.