JPH0455719A - Gear detector - Google Patents

Abstract

PURPOSE:To improve detecting accuracy and detecting reliability by orthogonally intersecting the magnetism detecting direction of a Hall element with the direction of the magnetic flux generated by a magnet. CONSTITUTION:The attaching direction of a Hall IC 4 is set so that a magnetism sensing direction (x) is orthogonally intersected with a magnetic-flux direction (y). When a protruding part 2 agrees with the Hall IC 4 by rotating a rotary body 3, the direction of the magnetic flux passing an element 4' becomes orthogonal. Therefore, the magnetic vector which is applied on the element 4' becomes zero. At a position where the protruding part 2 is slightly deviated with respect to the Hall IC 4, the magnetic vector is obtained, and the output is generated. Thus, the detecting accuracy can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gear detection device used for speed detection, rotation detection, angle detection, and the like.

[Prior Art] A conventional Hall IC type gear detection device for detecting the rotation of, for example, an engine has a structure as shown in FIG.

That is, a rotary body 3 having gear-shaped protrusions 2 formed at regular intervals on the circumferential surface is fixed to the rotary drive shaft 1, and a flat Hall element 4° is mounted on the circular surface of the rotary body 3. A sensor 7, which is formed by coaxially arranging and combining components such as a Hall IC 4, a pole piece 5, and a magnet 6, which are internally arranged, is formed on the circumferential surface of the rotating body 3 as the rotating body 3 rotates. As each protrusion 2 approaches the Hall IC 4 intermittently, the magnetic flux density passing through the Hall IC 4 changes,
Hall IC generated due to the amount of change in magnetic flux density
The rotational speed or number of rotations of the rotating body 3 is detected based on the pulses generated by 4. That is, since the direction of magnetic sensitivity of the Hall element 4' installed in the Hall IC 4 is arranged in a direction parallel to the direction of magnetic flux generated by the protrusion 2 and the pole piece, the rotation of the rotating body 3 acts on the Hall IC 4. The magnetic flux density has a period as shown in Fig. 7(a), and the sensor output (pulse) as shown in Fig. 7(b) is based on the sensitivity level (Bop) and (BRP) of the Hall element 4° in this period. is caused.

[Problem to be solved by the invention] However, in a gear detection device having such a structure,
The smaller the gap between the Hall IC 4 and the rotating body protrusion 2, the greater the magnetic flux force that the Hall element 4' receives.
Figure 7(b) relates to the magnetic flux density as shown in Figure (a).
It is possible to generate a clear output pulse as shown in
For example, if the gap between the Hall IC 4 and the rotating body protrusion 2 becomes too narrow due to a mounting dimensional error between the rotating body 3 and the sensor 7, the magnetic flux density acting on the Hall element 4° decreases. Due to this, for example, as shown in Figure 7(C), the sensitivity level (Bop) of the Hall element 4°,
The magnetic flux density deviates from (BRP), as shown in Figure 7(d).
As shown in , no sensor output occurs and detection becomes impossible. In order to eliminate this undetectability, the sensitivity level (B
It is conceivable to lower the sensitivity level (op) and (BRP) to the position shown by the dotted line in Fig. 7(c), but changing the sensitivity level requires changing the control circuit, which is difficult and expensive. there were.

[Means for Solving the Problems] The present invention has been made by focusing on such problems, and is intended to solve the conventional problems by making the magnetic detection direction of the Hall element perpendicular to the direction of magnetic flux from the magnet. be.

[Embodiment] The present invention will be explained in detail below based on the embodiment shown in FIGS. 1 to 5. The same parts between the structure of this embodiment and the structure explained in the conventional example Add the symbol used in
Detailed explanation of the same structural parts will be omitted.

That is, 1 is a rotating shaft, 2 is a protrusion formed at regular intervals on the circumferential surface of the rotating body 30, 7 is a Hall IC 4, and a pole piece 5.
, magnet 6. The hall IC
4 has a Hall element 4° installed therein, and the mounting direction of the Hall IC 4 equipped with this Hall element 4° to the pole piece 5 is the magnetic sensitivity direction of the Hall IC (
The requirement is that the magnetic flux direction (X) be arranged so as to be orthogonal to the magnetic flux direction (Y) by the magnet 6.

In this way, the Hall IC 4 can be installed by rotating the rotating body 3 while setting the magnetic sensitivity direction (X) of the Hall element 4' in a direction perpendicular to the magnetic flux direction (Y). As shown in (a), when the Hall IC 4 is located at the midpoint between both protrusions 2, and as shown in FIG. 2(C), when the protrusion 2 matches the Hall IC 4, the Hall element Since the direction of magnetic flux passing through 4° is perpendicular, the magnetic vector received by the Hall element 4° becomes zero. Also, Figure 2 (
As shown in b) and (d), at a position where the protrusion 2 is slightly shifted in the left-right direction with respect to the Hall IC 4, the magnetic vector becomes the illustrated magnetic vector and an output is generated. When the relationship between the magnetic flux density of the rice and the output is shown in FIGS. 3(a) and 3(b), a sensor output (pulse) which is the same as the conventional zero can be obtained. In other words, Fig. 3(a) shows a case where the gap between the Hall IC and the protrusion 2 is relatively narrow and the magnetic sensitivity due to the Hall element 4° is good, but the gap is wide and the magnetic sensitivity due to the Hall element 4° is good. Even if the sensitivity weakens, as shown in Figure 3(c), even if the magnetic flux density received by the Hall element 4° decreases, the sensitivity level of the Hall element 4'' can be positioned within the magnetic flux density period. As shown in (d), the same sensor output as when the gap is small can be obtained, and the detection accuracy is improved.

4 and 5 show other embodiments of the present invention,
On the circumferential surface of the rotating body 3, protrusions 2 are arranged in two rows in the thickness direction of the rotating body and at regular intervals in the circumferential direction. The sensor 7 is positioned in the middle so that the magnetic detection direction (X) of the Hall element 4° is orthogonal to the magnetic flux direction (Y). Therefore, according to this embodiment, due to the rotation of the rotating body 3, the Hall IC 4
is located at the middle of each protrusion 2 in both rows, the direction of the magnetic flux passing through the Hall element 4° is perpendicular, as shown in Fig. 5(b), and the direction of the magnetic flux received by the Hall element 4° is perpendicular. The magnetic vector becomes zero. Also, the Hall IC4 is shown in Figure 5 (
As shown in a) or (b), when one of the protrusions 2 arranged in two rows is approached, a magnetic vector is generated as shown in the figure, and as a result, as shown in FIG. A similar sensor output can be obtained.

Therefore, according to this embodiment, by setting the magnetic detection direction of the Hall element in a direction perpendicular to the direction of the magnetic flux generated by the magnet, the width of the gap between the Hall element and the rotating body protrusion varies or increases. Even if the sensor output is obtained by the Hall element, it is possible to reliably obtain the sensor output, thereby providing a gear detection device with excellent detection accuracy and detection reliability.

[Effects of the Invention] As described above, the present invention incorporates a rotor 3 made of a magnetic material in which irregularities are formed at regular intervals on the circumferential surface or side surface, and a Hall element 4° disposed close to the irregular surface of the rotor. In a gear detection device comprising an integrated circuit and a detection sensor 7 equipped with a magnet 6 disposed on the back of the integrated circuit and exerting a magnetic flux on the rotor 3 via the integrated circuit, the magnetic detection of the Hall element 4' is performed. Since this is a gear detection device in which the direction (Xl) is arranged perpendicular to the magnetic flux direction (Y) by the magnet 6, it is possible to detect variations in the width of the gap between the Hall element 4° and the irregularities of the rotor 3, or Even if the width increases, the sensor output from the Hall element 4° can be reliably obtained, which has the effect of providing a gear detection device with excellent detection accuracy and detection reliability. It will be done.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the gear detection device according to the present invention, FIGS. 2(a) to (d) are explanatory diagrams of its operation, and FIG.
Figures (a) to (d) are explanatory diagrams showing the relationship between magnetic flux density and sensor output in this embodiment, Figure 4 is a perspective view showing another embodiment of the present invention, and Figure 5 (a) 〜(C) is an explanatory diagram of its operation, FIG. 6 is an explanatory diagram of the structure of the conventional example, and FIGS. 7(a) to (d)
is an explanatory diagram showing the relationship between magnetic flux density and sensor output in a conventional example. 1...Rotating shaft 2...Protrusion 3...Rotating body 4...Hall IC4゛...Hall element
5...Pole piece 6...Magnet F...Sensor Figure 1 and 4 others Figure 3 (C) Bottom (d) Gear knob, small gear knob, large Figure 6, Figure 4, Figure 5, (a) (b) ) (C) Figure (b) (C) (b) (d)

Claims (1)

[Claims] 1. A rotor (3) made of a magnetic material with irregularities formed at regular intervals on the circumferential surface or side surface, an integrated circuit incorporating a Hall element (4') disposed close to the irregular surface of the rotor, and the back of the integrated circuit. A gear detection device comprising a detection sensor (7) equipped with a magnet (6) which is disposed in and applies a magnetic flux to the rotor (3) via the integrated circuit, the magnetic detection of the Hall element (4') A gear detection device characterized in that the direction (X) is arranged perpendicular to the magnetic flux direction (Y) by the magnet (6).