JPS5979858A - Apparatus for detecting rotation - Google Patents

Abstract

PURPOSE:To measure a rotary speed with high accuracy by a sufficiently large number of detection signals, by a method wherein magnetic signals are recorded to a rotor at an equal interval lambda and a plurality of resistance bodies are arranged in the range of (d) in close vicinity to said rotor while the range (d) is made smaller than the interval lambda. CONSTITUTION:Magnetic signals corresponding to N-poles and S-poles are recorded to the peripheral surface of a rotor 11 at an equal interval lambda and a magneto-resistance element 13 is fixed and arranged in adfacent and opposed relation to said rotor 11. The resistance element 13 is constituted by parallelly arranging n-numbers of resistance bodies R1-Rn between a range (d) on an insulating substrate 14 and these resistance bodies are successively connected in series. In this case, the range (d) is made smaller than the interval lambda. When the rotor 1 is rotated, an output signal is issued to a terminal (b) but pulse signals n-times of recording numbers of magnetic signals are obtained by one rotation of the rotor 11 and, if theses signals are counted while specifying a time width, a rotary speed can be measured with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotation detection device using a magnetoresistive element for detecting the rotation speed of a rotating device.

To configure a rotation detection device using a magnetoresistive element, a rotating body is provided so as to rotate coaxially with the rotating device to be measured. Magnetic signal recording sections corresponding to the above are set at equal intervals on the circumferential surface of the rotating body. A magnetoresistive element is completely fixedly installed in close proximity to the circumferential surface of the rotating body, and the structure is configured such that this magnetoresistive element detects the close passage of the magnetic Ig recording section accompanying the rotational movement of the rotating body. . That is, the rotational speed of the rotating body is determined by the time interval of the detection signal from the magnetoresistive element.

It is something to be released.

Therefore, for example, on an S platform in which n magnetic signals are recorded at equal intervals on the circumferential surface of a rotating body, one
The rotation causes n detection signals to be detected by the magnetoresistive element.

In the rotation detection mechanism, in order to detect the rotation speed with higher accuracy, fD' of the detection signal of one revolution υ of the rotating body is
It is required to increase ffi.

To this end, it is sufficient to increase the number of magnetic signals recorded in the recording section corresponding to the outer periphery of the rotating body, but there is a limit to how much the number of magnetic signals recorded on the rotating body can be increased.

This invention was developed in view of the above-mentioned points, and it is possible to generate a sufficiently larger number of detection signals than the number of recorded magnetic signals in response to the rotation of a rotating body having magnetic signals recorded on its circumferential surface. The present invention aims to provide a rotation detection device that can measure the rotational speed of rotating equipment with high precision.

That is, in the rotation detection device according to the present invention, a magnetoresistive element is fixedly disposed facing a rotating body on which magnetic signals are recorded at intervals of λ on the circumferential surface, and the magnetic resistance element is arranged to face the rotation of the rotating body. A plurality of ferromagnetic resistors are disposed on one arm 7'' in a width d in the transverse direction of the accompanying magnetic signal recording section, and the relationship 0<d<λ It was designed so that it would fly.

An embodiment of the present invention will be fully described below with reference to the drawings. Figure 1 shows the schematic configuration of the 11Fi axis 12
This is a rotating body that is rotationally driven by a rotating device to be measured (not shown), and magnetic signals corresponding to N poles and S poles are magnetized and recorded at multiple locations at equal intervals on the outer peripheral surface of this rotating body 1. It's hot. A magnetoresistive element 13 serving as a detector is placed close to the outer peripheral surface of this rotating body 11.
is set to be fixed, and the magnetic field generated by the magnetic signal recorded on the rotating body 11 acts on the magnetoresistive element 13 in response to the rotation of the rotating body 11.

FIG. 2 shows the magnetoresistive element 13 taken out and the rotating body 1.
This magnetoresistive element 13 is constructed of one chip by an insulating substrate 14.

That is, a plurality of thin wire-shaped resistors R1 to Rnt are arranged in parallel to the insulating substrate 14, and the resistors R1 to Rn are made of ferromagnetic material deposited on the surface of the insulating substrate 14. The structure is removed by etching a thin film, and each of the resistors R1 to Rn is set to extend in the axial direction of the rotating body 1. And these resistors R1 to R
n are successively connected in series so that terminals a and b are formed at both ends thereof.

Here, the width of the range in which the resistors R1 to Rn are arranged, that is, the distance d between the first resistor R and the last resistor Rn
is 0 for the magnetic signal recording section interval λ of the rotating body 11.
The relationship is set to be 〈d〈λ.

That is, the rotation detecting device configured as described above; when one of the N and S magnetic signal recording parts of the rotating body 1 comes into contact with one of the resistors R1 to Rn, , so that the resistance value of the resistor changes rapidly. Therefore, while one magnetic signal recording section moves λ, the resistor R
The magnetic field from the magnetic signal recording section acts on R1 to Rn sequentially, and the resistance value changes between terminals a and l) as shown in Figure 3, depending on the arrangement of resistors R1 to Rn. A change occurs, and a pulse-like detection signal corresponding to this change is output. In other words, for one rotation of the rotating body 11, 9 times the number of magnetic signals recorded on this rotating body 1.
In order to obtain a pulse-like detection signal, this pulse-like detection (&1 counting operation) makes it possible to measure the rotational speed of the 6-rotating body 110 with high precision.

In this case, n resistors R1 to R1 are set in a range of width d.
The mutual spacing between Rn does not need to be particularly constant;
As shown in the figure, even if the interval is unspecified, it is possible to measure the rotational speed of the rotating body 11 with sufficiently high accuracy by dividing the recessed detection signal in the specified time range.

In the above embodiment, the plurality of resistors R1 to Rni were connected in series, but these were connected in parallel as shown in FIG.
Terminals a and b'i may be provided at both ends thereof. In this case, a resistor R that is insensitive to the magnetic field may be formed on the surface of the insulating substrate 14, and the detection circuit may be configured as a fixed resistor R (i-). In this case, Resistor R is connected between terminal A and terminal C.
, connect a constant voltage, constant current power source between the terminals e. Then, an output signal corresponding to a change in the resistance value of the resistors R1 to Rn is taken out from the terminal.

FIG. 5 shows the output signal from the magnetoresistive element 13 when the magnetic signal recording section of the rotating body 11 moves by λ in the above-mentioned apparatus.

As described above, according to the present invention, it is possible to obtain a sufficiently large number of pulse-like detection signals corresponding to one revolution of the rotating body.For example, when the rotating body is small and has a small total inertia. 9, it is possible to measure the rotational speed with sufficiently high accuracy.

This means that it can be very effectively incorporated as a rotational speed detection means for various types of rotating equipment.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a rotation detection device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an enlarged view of the magnetoresistive element portion of the device, and FIG. 3 is a detection signal of the device. FIG. 4 is a diagram showing another embodiment of the present invention, and FIG. 5 is a diagram showing detection signals in this embodiment. 11... Rotating body, 13... Magnetoresistive element, 14...
- Insulating substrate, R1-Rn...Resistor (by ferromagnetic thin film).

Claims (1)

[Claims] A rotating body whose peripheral surface is set to record a plurality of magnetic signals at equal intervals, an insulating substrate set to face the magnetic signal recording surface of this rotating body, and a rotation of the rotating body with respect to this substrate surface. A plurality of ferromagnetic thin film resistors arranged in parallel in the direction transverse to the magnetic signal recording section are provided, and the width of the range in which the resistor is arranged is equal to the distance between the magnetic signal recording sections of the rotating body. A rotation detection device characterized in that the interval width is also small.