JPS59151018A - Position detecting device - Google Patents

Abstract

PURPOSE:To obtain a position signal of high resolution without requiring a machine work of high accuracy by supplying a since wave of two phases which are 90 deg. out of phase from each other, to a magneto-resistance effect element, and detecting electrically a phase variation of a phase modulating signal by the accuracy of integer multiples. CONSTITUTION:A cosine wave signal Db which leads a sine wave signal Da of frequency (f) by a phase angle of 90 deg. is inputted to a series connecting point 13b of elements 3d, 3f of a magneto-resistance element. Also, a terminal 7a is connected to a + input of a differential amplifier 14, and a terminal 7b is connected to a - input. Subsequently, an output Ea of the amplifier 14 is inputted to a direction pulse generator 16. The pulse generator 16 detects a phase variation of a phase modulating signal F of frequency (f) whose phase is modulated in accordance with a relative position of a moving piece and a stator by a clock signal G of frequency nf of integer multiples of a constant frequency (f), and outputs a direction pulse H or I as an incremental position signal. In this way, a position signal of high resolution is obtained without a machine work of high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a positioning control base in which the amount of movement of a movable element opposing a stator and moving is detected by generating incremental directional pulses for each predetermined amount of movement. The present invention relates to a position detection device.

This type of position detection device includes a stator 5 in which teeth 5a and grooves 5b are alternately formed with a constant bit P, as shown in FIG.
Magnetoresistive element elements 3a, 3b, . . . are formed on a silicon substrate 3 at a pitch of P/4, for example.

It has a mover in which a magnetoresistive effect element having an array of magnetoresistive elements 3h and a permanent magnet 4 are coupled by a pedestal 2, and the mover is held at a predetermined interval opposite to a stator 5 and is moved in the length direction. It is slidably held on the bracket 1 so as to be able to move.

FIG. 2 is a plan view showing an example of the element arrangement of the magnetoresistive element, and the magnetoresistive element arrays 3a to 3h are P/
The magnetoresistive elements (hereinafter referred to as elements) 3a to 3d are arranged at four intervals, and one ends of the magnetoresistive elements (hereinafter referred to as elements) 3a to 3d are connected in common to the terminal 7a, and the elements 3e to 3h are connected to the terminal 7b. The other end of each element is connected to terminals 6a and 6h, respectively. The resistance value of each of these elements changes depending on the amount of magnetic flux passing through each element. Therefore, the relative position t of the mover with respect to the stator 5 can be detected by detecting all the changes in the resistance values of the above-mentioned elements.

FIG. 3 is a circuit diagram showing an example of electrical connections of a conventional position detection device. That is, element 3a.

3gk are connected in series, and the connection point is connected to the + input of the differential amplifier 9a, and the series connection point of elements 3c and 3e is connected to the - input. Further, element 3 is connected to the + input of the differential amplifier 9b.
The series connection points of elements 3d and 3f are connected to the series connection points of elements 3d and 3f.

The outputs of differential amplifiers 9a and 9b are respectively connected to comparators x
It is input to oa and xob and outputs a rectangular wave Ca.

Cbvc converted. Then, DC voltage V is applied from terminal 6.

All the signals are supplied and inputted to the terminal 7a via the resistor 8ai.

The terminal 7b is grounded through a resistor 8bi.゛Element 3
a, 3e are in phase with the pitch P, and element 3. c.
, 3gfd are shifted by P/2 of elements 3a and 3e, respectively, so when the mover moves on the stator 5, the output A (L of the differential amplifier 9a becomes as shown in FIG. 4(a)) .The figure (b) shows the output Ahi of the differential amplifier 9b,
It is 90° ahead of the output AcL. Output Ab is A(L
Whether xv advances or lags is determined by the moving direction of the mover.

The output ca, C, 6 of the comparator lOa, 10b is
0 as shown in Figures 4(C) and (d), respectively.
In other words, the outputs CcL and Cb have a G deviation of 1 of the mover.
It is a rectangular wave with a period corresponding to the pitch movement, and its phase difference is P/4. In other words, one rectangular wave is output for one pitch movement of the mover, and the moving direction is output C4.
, Ch.

In the conventional example described above, the resolution of position detection is determined by the pitch P of the teeth and grooves formed on the stator.

Therefore, in order to increase the resolution, it is necessary to make the pitch P small and the spacing between the elements 38 to 3h to be equally small. This is difficult to process and requires high-precision machining, making it expensive. Furthermore, as the pitch P becomes smaller, the widths of the teeth 5a, the grooves 5b, and the elements 3a to 3h also become smaller, so the magnetic flux that each element receives from the permanent magnet 4 becomes smaller, and the change in magnetic resistance of the elements 38 to 3h decreases. Therefore, the whole bone is easily affected by leakage magnetic flux from the outside,9 and the accuracy of the position signal is impaired.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional drawbacks and to provide a position detection device capable of obtaining a high-resolution position signal without requiring high-precision machining.

The position detection device of the present invention includes a stator in which teeth and grooves are alternately formed at a constant pitch in the length direction, and magnetoresistive element arrays are arranged on a substrate at an integer fraction of the pitch. The magnetoresistive element has an array of magnetoresistive elements and a permanent magnet that excites the magnetoresistive element, and a mover that faces the stator and is held at a predetermined interval and moves in the length direction of the stator. In the position detection device, a two-phase sine wave having a constant frequency and mutually different phases is inputted to the magnetoresistive element, and the phase modulation signal of the same frequency is phase-modulated according to the relative position of the moving element and the stator. A means for outputting
The apparatus is characterized by comprising means for detecting a phase change in the phase modulation signal with an accuracy of an integral multiple of the constant frequency and generating an incremental position signal.

Next, one embodiment of the present invention will be explained in detail with reference to all the drawings.

FIG. 5 is a diagram showing an embodiment of the present invention.

That is, each element 3 of the magnetoresistive element shown in FIG.
8 to 3f are connected as follows. Elements 3a, 3gi
A sine wave signal D of frequency f is connected in series from the connection point 13a.
(L is manually powered, and the series connection point of elements 3C and 3e is grounded. Also, the above signal Da is connected to the series connection point 13b of elements 3d and 3f, and the cosine wave signal Dh-i advanced by 1190° is manually powered, and the element The series connection point of 3b and 3h is grounded.Then, the terminal 7a is connected to the terminal of the differential amplifier 14, and the terminal 7a is connected to the terminal 7a of the differential amplifier 14.
0 differential amplifier 1 connected to the power of the b-group differential amplifier 14
The signal F converted into a logic level signal by the output Ed1 of the output signal F is input to the direction pulse generator 16. The direction pulse generator 16 detects the phase change of the input signal F using a clock signal G having a frequency nf that is n times the constant frequency f, and converts the direction pulse H and fc into an incremental position signal. Output. The signal F is a phase modulated signal with a frequency f that is phase modulated according to the relative position between the movable element and the stator. In this embodiment, the connection circuit for each of the above-described elements 3a to 13h, the differential amplifier 14, and the comparator 15 constitute the entire means for outputting the phase modulation signal.

The directional pulse generator 16 can be configured as shown in FIG. 6, for example. That is, the clock signal G-q with one frequency rLJ is divided by i/n by the frequency divider 20 to create a rectangular wave signal 21i with a frequency f, and the phase difference between the signal 21 and the phase modulation signal P' is detected by a phase detector. 22. However, it is assumed that the initial phase t of the rectangular wave signal 21 is matched with the phase modulation signal F. Phase detector 22f/71
: is inputted with clock signal G, and the phase of phase modulation signal F is the phase of signal 21 J: ! When it has advanced by more than It 1/nf, the direction pulse is output once. By supplying the direction pulse 1 to the frequency dividing circuit 20, the frequency dividing circuit 2
Change the division ratio of 0 and change the division period'? Shorten by r l/nf. As a result, the phase difference between the signal 21 and the phase modulation signal F becomes 1/1Lf or less, and the phase detector 22 has no output. The phase of the phase modulation signal F advances further and becomes signal 2 again.
When the phase difference with 1 becomes 1ALf or more, the direction pulse I
is output, and the frequency dividing ratio of the frequency dividing circuit 20 is changed by the total lparnu. Therefore, since one direction pulse (2) is output every time the phase of the phase modulation signal F increases by VnfM, the direction pulse can be superior to the incremental position signal.

That is, the movement of the movable element P/n can be detected by one directional pulse. As the movable element moves in the opposite direction, the phase of the phase modulation signal F gradually lags behind.

When the phase delay becomes 1/f, the phase detector 22 outputs a direction pulse H, and the frequency divider circuit 20 increases the frequency dividing period kl/nf when the direction pulse 1 is input manually. Therefore, one direction pulse H is output for every four pinch movements of the moving element. It is distinguished by the moving force direction σ direction pulse H9■.

FIG. 7 is a time chart showing signals of each part of this embodiment. FIG. 5A shows a sine wave signal Db and a cosine wave signal Db having a constant frequency f. FIG. 5(b) shows the output E of the differential amplifier 14 (in FIG. 5). Ll-show. The output E (L is the frequency f, and its phase corresponds to the amount of movement of the mover. The phase changes by 360 degrees by moving the mover by 1 pitch P. In the left half of the figure, the phase gradually changes. All delayed signals are shown, and the right half shows signals whose phase gradually advances.
C) shows the phase modulation signal Fi output from the comparator 15 (in FIG. 5). FIG. 4(d) shows the clock signal G. FIG. 4(e) shows a direction pulse H which is output every time the phase of the phase modulation signal F lags by l/n, and a direction pulse I=i which is output every time the phase advances by 1/rLf.

In this embodiment, the teeth 5a of the stator 5 shown in FIG.

Movement of the mover is detected with an accuracy of l/n of the pitch P without changing the pitch P of the grooves 5b and without changing the arrangement pitch of the elements 33 to 3h of the magnetoresistive element shown in FIG. In other words, it is possible to easily obtain a resolution twice that of the conventional method without increasing the machining accuracy. Further, since there is no need to reduce the width of the magnetoresistive element, the magnetic flux received from the permanent magnet is small, and it is difficult to be affected by leakage magnetic flux from the outside, so that highly accurate position detection is possible. That is, manufacturing of stators and magnetoresistive elements.
As described above, in the present invention, two-phase sine waves having a constant frequency and a phase difference of 90 degrees are generated by magnetoresistive effect. A phase modulation signal of the same frequency that is phase-modulated according to the relative position of the moving element with respect to the stator is outputted, and a phase change of the phase modulation signal is electrically detected with twice the accuracy. Because of this structure, a high-resolution position signal can be produced without requiring high-precision machining, and a position detection device with extremely high accuracy can be provided at a low price.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a position detection device using a magnetoresistive element, Fig. 2 is a plan view showing the magnetoresistive element, and Fig. 3 is a side view showing a position detection device using a magnetoresistive element.
The figure is a circuit diagram showing an example of electrical connection of a conventional position detection device, FIG. 4 is a waveform diagram showing signals of each part of the conventional example, and FIG.
6 is a block diagram showing an example of the configuration of the directional pulse generator of the above embodiment, and FIG. 7 is a waveform diagram showing signals of various parts of the above embodiment. In the figure, ■... Bracket, 2... Pedestal, 3
...Silicon substrate, 3a to 3h...Magnetoresistive element element, 4...Permanent magnet, 5...Stator, 5a...
・Teeth, 5b...Groove, 6a to 6h, 7a, 7b-
...Terminal, 8a, 8b...Resistor, 9a, 9b, 14
- Differential amplifier, 10a't10b, 15...
-) Inverter, 13a, 13b--Connection point, 16-
... Directional pulse generator, 20... Frequency divider circuit, 21...
- Rectangular wave signal, 22... Phase detector, F... Phase modulation signal, G... Clock signal, H,, I,... Directional pulse. Agent Patent Attorney Sumi 1) Toshi So Figure 1 Figure 2

Claims (1)

[Claims] A stator in which left and right tooth grooves are alternately formed at a constant pitch in the length direction, and a magnetoresistive element in which arrays of magnetoresistive element elements are arranged and formed on a substrate at a pitch that is an integer fraction of the above pitch. and a mover which has a permanent magnet that fully excites the magnetoresistive element and is held at a predetermined interval opposite to the stator and moves in the length direction of the stator. means for inputting two-phase sine waves of constant frequency and mutually different phases into an effect element and outputting a phase modulated signal of the same frequency that is phase-modulated according to the relative position of the movable element and the stator; An incremental position signal that detects the phase change of the modulated signal with an accuracy of an integral multiple of the above-mentioned constant frequency? A position detection device characterized by comprising a means for generating a signal.