JPS5913912A - Magnetism detecting sensor - Google Patents

Abstract

PURPOSE:To realize size reduction and high sensitivity by inserting a magnetism sensing element in a notch part provided to a substrate and constituting the magnetism sensing element part of a case into nonmagnetic thin-plate structure. CONSTITUTION:The magnetism sensing element 9 is inserted and fitted in the notch hole 8a at the magnetism sensing element part of the substrate 8. Consequently, distance AG15 is reduced by the thickness of the substrate and the magnet side part 7a of the magnetism sensing element 9 of the case 7 is made of a nonmagnetic stainless steel thin plate 13 to reduce the AG15 more. Thus, the AG15 is reduced sufficiently and the overall thickness 14 of the sensor is also reduced to form a hihg-sensitivity magnetism sensor which is sized small on the whole.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic detection sensor used in a rotation detection device or the like.

When used in a deteriorating environment (for example, inside the engine room of a car), it is undesirable to expose the magnetic sensing element (1) from the viewpoint of reliability.
As shown in the figure, it is housed in a case and used. That is, FIG. 1 is a configuration diagram of a conventional magnetic detection sensor, where 1 is a shaft, and 2 is a magnet rotor that rotates in synchronization with the shaft 1 and has a magnetic signal magnetized on its circumference. 3 is a magnetic sensor case made of a non-magnetic material. 4 is a magnetic sensing element, and 5 is a substrate on which it is fixed. Here, whether the case 3 is made of resin or a die-cast case,
A certain degree of wall thickness is required (usually about 1 thick or more). Therefore, the distance 6 from the surface of the magnet rotor 2 to the magnetic sensing element 4 (hereinafter referred to as AG) becomes considerably large.

However, as shown in Figure 2, the magnetic field strength is AC3
As the value increases, the value decreases rapidly, and this decrease is particularly severe when the magnet rotor 2 is multi-pole magnetized. Therefore, in order to realize a magnetic sensor with excellent detection accuracy, it was necessary to make AC3 as small as possible.

However, for example, whether it is resin molding or aluminum die (2) cast case, it has been difficult to reduce the thickness too much from the viewpoint of manufacturing and strength.

Therefore, an object of the present invention is to provide a compact and highly sensitive magnetic sensor by inserting a magnetic sensing element into a notch provided in a substrate and making the magnetic sensing element part of the case a non-magnetic thin plate structure. shall be.

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 3 shows the magnetic sensor structure of the present invention. 2 is a magnet rotor with magnetic signals on its outer circumference, and shaft 1
and rotates in synchronization with the shaft 1. The magnetic sensor head 17 includes a resin frame 7 in which a non-magnetic stainless steel thin plate (thickness t=0.3 fl in this embodiment) 13 is integrally molded on the front surface of the magnetic sensing element 9, and a resin lid 7A. ,
It consists of a ceramic substrate 8 having a notch hole 8a in the magnetic sensing element 9 portion. A signal output section formed by insert-molding an input/output bin 11 is formed in the frame 7, and is connected to the electrical wiring on the ceramic substrate 8 by a connector wire 11a. Further, electric wiring is printed on the upper surface of the substrate 8, and connects the magnetic sensing element 9, the waveform processing (3) circuit ICI O, and the output connect wire lla. Further, the space within the frame 7 is filled with silicone rubber 12 to protect each element.

FIG. 4 is an external view of the sensor head 17, and FIG. 5 is a structural view of the sensor head 17 when it is assembled into a distributor. At the bottom of the frame 7, there is a flange part 7b with a mounting hole 16 for fixing the sensor head, and a screw 18.
It is attached and fixed to the distributor housing 20 via. The housing 20 of the distributor 26 is fixed to the internal combustion engine through holes 24 formed in the flange 20a through bolts (not shown). The motion of the internal combustion engine is transmitted to the shaft 1 via the gear 23, so that the magnetic rotor 2 rotates in synchronization with the internal combustion engine.

21.22 is a distributor cap and a power distribution rotor for high voltage power distribution. In addition, the sensor head 17
The signal is taken out from inside the distributor via a grommet 25 and connected to the outside through a connector (4) coupler 19 attached to the tip of the wire.

The thin plate 13 may be made of any non-magnetic material, but considering its strength and heat resistance, it is preferably made of highly magnetic stainless steel since it is used as a rotation sensor for an internal combustion engine.

In the above configuration, the hole 8 formed in the magnetic sensing element portion of the substrate 8
By inserting and attaching the magnetically sensitive element 9 to a, the AG15 can be made smaller by the thickness of the board, and the magnet side portion 7a of the magnetically sensitive element 9 of the case 7 can be replaced by a thin plate 13 made of non-magnetic stainless steel.
By doing so, AG15 can be further made smaller. With these combinations, the AG 15 can be made sufficiently small, and the thickness 14 of the entire sensor can also be made small, and as a whole,
A small, highly sensitive magnetic sensor can be realized.

FIG. 6 shows another embodiment of the invention. When the impeller 32 made of magnetic material attached to the shaft 1 rotates, the magnet 3
Since the magnetic field from 4 is conducted or cut off, the rotation of the shaft 1 is detected by applying a change in the magnetic field to the magnetic sensing element 36. Again, the magnetic sensing element 36 and
Reducing AG(5) of the magnet 34 increases detection sensitivity. Therefore, the magnetic element 36 side of the case 33 of the sensor head 30 is made of a non-magnetic stainless thin plate 37, and the output wire 38,
It is integrally molded together with the magnet 34 and the like. In addition, the board 35
A hole 35a is opened in the magnetically sensitive element part of the magnetically sensitive element 3.
6 can be inserted. The space 39 is molded with silicone rubber after the parts are assembled. In this case, the magnetic sensing element part of the case is made thinner, and the magnetic sensing element 3
6 is embedded into the substrate 35, the magnetic sensing element 36
can be brought significantly closer to the magnet 34 side, and as a result, detection accuracy can be improved.

Further, in this case, the same applies to a sensor having a structure in which a magnetic path is combined with a magnet or a magnetic sensing element, or a sensor using an element in which a magnetic sensing element and a processing circuit are integrated into an IC instead of a magnetic sensing element.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the main part of a conventional sensor, Figure 2 is a magnetic field strength characteristic diagram, Figure 3 is a cross-sectional view of the main part of the sensor of the present invention, and Figure 4 is a cross-sectional view of the main part of a conventional sensor.
3 is a perspective view showing the sensor head of the sensor shown in FIG. 3, FIG. 5 is a partially sectional front view showing a distributor to which the sensor shown in FIG. 3 is applied, and FIG. 6 is another embodiment of the sensor of the present invention. FIG. ■...shaft, 2...11 stone rotor, 7.7A,
13... Resin frame constituting the case, resin lid, non-magnetic stainless thin plate, 8, 35... Substrate, F3a
. 35a... Notch hole forming the notch part, 9, 36...
Magnetic sensing element, 33...Case, 37...Nonmagnetic stainless steel thin plate. Representative Patent Attorney Takashi Okabe (7) @Figure 1 Figure 3 Figure 4 65

Claims (1)

[Scope of Claims] 1. A magnetic detection sensor including a magnetic sensing element, a board for fixing the magnetic sensing element and inputting/outputting electric signals, and a case housing the magnetic sensing element, in which the magnetic sensing element of the substrate is fixed. A notch is provided in the part, and the magnetically sensitive element is inserted into the notch, and the magnetically sensitive element part of the case is made of a non-magnetic thin plate structure to reduce the distance from the outer wall edge of the sensor to the magnetically sensitive element. magnetic detection sensor. 2. The magnetic detection sensor according to claim 1, wherein the non-magnetic thin plate of the magnetic sensing element portion is made of a non-magnetic stainless steel thin plate.