JPS58111719A - Displacement quantity detector - Google Patents

Abstract

PURPOSE:To adjust the position signal which detects the relative displacement quantities between magnetizing bodies and detecting heads highly accurately and simply even after the detecting heads are fixed, by synthesizing the outputs detected by two detecting bodies by a synthesizing means whose synthesizing ratio can be varied. CONSTITUTION:The relative displacement quantities between the magnetizing bodies 1 and 1' and the heads 2 and 2' can be precisely detected through the magnetizing bodies 1 and 1', the detecting heads 2 and 2' which face said bodies, respectively, detector circuits 3 and 3', and the like. In this case, even though a distance between the heads 2 and 2' is L+l with respect to a distance L between the magnetizing bodies 1 and 1', and the head 2' is separated by l and fixed, the synthesizing ratio is varied by varying the ratio of resistors R1 and R2 which form a synthesizing position signal. Therefore, even after the detecting heads are fixed, the position signal which detects the relative displacement quantities between the magnetic bodies and the detecting heads can be adjusted highly accurately and simply so that the position of the detecting heads are not substantially deviated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improvement in a displacement detector, particularly in a device for detecting the relative displacement between a magnetic body and a detection head, so that the position signal can be easily adjusted with high accuracy even after fixation. Regarding.

As shown in FIG. 1, the displacement detector consisting of the magnetic body 1, the detection head 2, and the detection circuit 3 can detect the relative position between the magnetic body and the detection head 2 with high precision.
J It is widely used in various fields as a mitsu switch or a displacement detection device.

However, conventional displacement detectors have the disadvantage that adjustment of position signals is inconvenient and time consuming. That is, once the magnetic body 1 and the detection head 2 are attached to a machine tool, etc.,
Naturally, the relationship between the relative position between the two and the position signal as the detection output is fixed, so if you want to make adjustments such as slightly shifting this relationship, you can change the relationship between the magnet L or the detection head 2. The position must be shifted and fixed by an amount to obtain the above relationship, and it is quite difficult to perform such fine mechanical adjustment with high accuracy, requiring a large amount of time and man-hours.

Therefore, as shown in FIG. 2, a method has been proposed in which the detection circuit 3 is configured to electrically adjust the position signal. In the figure, Dl and D2 are diodes, OP is an operational amplifier, ■R1 to ■R3 are variable resistors, AC is an AC bias power supply, -) -E, -E are DC bias painters, and the foam 1
Depending on the relative position between the detection head 2 and the detection head 2, a position signal ``o'' as shown by the solid line in FIG. 3 is obtained. According to such a detection circuit 3, the position signal Vo can be adjusted as shown by the dotted line in FIG. 3 by adjusting any of the variable resistors VR,1 to R3.

However, since the detection output, that is, the most stable level of the position signal, shifts depending on the position of the variable resistor, there is a drawback that it is difficult to achieve a large adjustment range.

The present invention has been made in order to improve the drawbacks of the prior art. Two sets of detection heads are arranged at a predetermined interval with respect to the magnet, and the detection outputs of the two sets are provided to a detection circuit to detect firing. By obtaining position signals corresponding to the relative positions of the body and each detection head, combining the respective position signals, and changing the combination ratio, the origin of the combined position signal can be arbitrarily set within the range of the above-mentioned intervals. The present invention is characterized in that the position signal can be easily adjusted with high precision even after the detector is fixed.

The present invention will be described below with reference to embodiments shown in the drawings.
In Fig. 4, for example, if two sets of detection heads 2, 2' are arranged for the magnetic generators 1, 1, and L and f have an interval of 1° 1' between the magnetic generators, the detection heads 2, 2 will have a distance of 1. Shift it to an interval of L+7. The detection output from each detection head is given to the detection circuits 3, 3 as described above, and as described above, the position signal (1) corresponds to the relative position between the magnetic body and the detection head. (1) 2 is obtained, and vl and (2) are synthesized by, for example, resistors R, , R2.

Therefore, the above position signal ■1. (2) As shown in FIG. 5, the respective origins are separated by the distance l. The linear portion of these signals can be approximated to the relative displacement X as follows.

■] = 1 ” (11V2 = 2
(x-1) (21 However, KJ and 2 are the gains of the detection head and detection circuit.

Therefore, since the output resistance of each detection circuit can be ignored, the position signal VO obtained by combining Vl and 2 is as follows.

1R2 Vo = Vl + V2 (3
1R, 1+ R2R, + R2 As is clear from equation (4), the synthesized position signal VO
By changing the ratio of KIRl and 2R2, that is, the synthesis ratio, the origin (Vo=O) can be set to correspond to any position within the range of x=Q~l.

To change the above combination ratio, for example, combine resistance R1 and 1t.
Just change the ratio to 2. That is, since K1 and K2 can be kept constant once the gap between the magnetic generator and the detection head is determined, the origin of VoH=O can be changed from 0 to 1 in total from equation (4).

FIG. 6 is an example of a circuit for implementing the above change method.
A variable resistor R for changing the ratio of R1 and R2 is connected to the output of the detection circuits 3, 3', and the detection heads 2, 2
' is a single AC bias power supply AC1+R-.An example of the circuit is shown in FIG. In the same figure, OPl and OP
2 is an operational amplifier, which includes detection circuits 2 and 2 and a combining resistor I, respectively.
(, , , R, 2, so that the gain adjustment can be changed. In the above embodiment, two magnetic bodies 1 are connected to , 1 was used, but the number of magnetizing bodies can be reduced to one by integrating two sets of detection heads as shown in FIGS. 8 and 9.

In the same figure, reference numeral 4 denotes a holding member, and even if the cores 5, 5' and coils 6 and 6' that make up the detection head 2゜2' are integrated into 5, the position synthesized by the variable resistance R for synthesis The point of the signal ``o'' can be arbitrarily set within the range of O-1 as in the previous embodiment. In particular, in this embodiment, since the detection head has an integral structure, the clearance between the magnetizing body and both heads can be set to be the same, the characteristics of both heads can be easily matched, and the alternating current bias can be supplied from the same power source. Therefore, since the detection sensitivity of both heads can be made almost the same, the above (
4) In the formula, 1 (] ÷ 2 =, R, + R2 = 1 pattern...detection circuit, R...variable resistor for synthesis.

Therefore, from the viewpoint of characteristics, it can be regarded as one detection head.

FIG. 10 is an actual measurement diagram showing the output characteristics at each point in the above embodiment.

As explained above, according to the present invention, even after the detector is fixed, the position signal can be finely adjusted with high precision, and the effect is remarkable in practical use.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the basic configuration of a displacement detector to which the present invention is applied, Fig. 2 is a circuit diagram showing an example of a conventional detection circuit in the displacement detector, and Fig. 3 is a circuit diagram thereof. 4 is a schematic diagram showing an embodiment of the present invention, FIG. 5 is an output characteristic diagram thereof, and FIGS. 6 and 7 are respective methods of changing the combination ratio of position signals in the embodiment. FIGS. 8 and 9 are circuit diagrams showing other embodiments of the present invention, and FIG. 10 is a circuit diagram showing another embodiment of the present invention.
The figure shows the measured output characteristics. ■, 1'... Magnetizing body, 2, 2'... Detection head, 3
, 38- Patent applicant Sony Magnescale Corporation Figure 1 Figure 2 Figure 3 Figure 4 × Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 3' 0M IvI2!11

Claims (1)

[Scope of claims] Displacement amount detection characterized by comprising a detection circuit that generates a position signal corresponding to the relative position between the generation means and the detection head, and a position signal synthesis means that synthesizes the position signals and whose synthesis ratio is variable. (2) The magnetic field generating means consists of one magnet generating body,
The displacement amount detector according to claim 1, wherein the detection head is integrally held. (3) The displacement detector according to claim 1 (i1), wherein the magnetic field generating means comprises two magnetizing bodies. (4) Each of the detection heads is connected to a single AC bias power source. Claim No. (1) characterized in that they are connected.
Displacement amount detector according to items (3) to (3) above.