JPS60173412A - Encoder - Google Patents

Abstract

PURPOSE:To read the linear movement extent of a rotating shaft with high resolution through simple constitution by reading magnetic marks which are magnetized at equal intervals at the periphery of a code disk successively through detection heads. CONSTITUTION:Magnetic marks 3a are magnetized at equal intervals (p) at the peripheral part of the code disk 3 which rotates rolling on a table surface in contact, and five detection heads 11-0, 11-2, 11-4, 11-6, and 11-8 are provided facing them. When head 11-0 coincides with a mark 3a completely, a current flowing through the opposite diode 16-0 attains to the maximum value to display the corresponding number 0 on a number display device 27 through an input/ output converting circuit 19, etc. Then, detection heads 11-0...detect marks 3a in order by the slight rotation of the disk 3 to display 2, 4, 6, and 8 successively so that the display moves to high-order digits every time the head 11-0 becomes coincident. Therefore, the number of movable parts is reduced and the handling is facilitated to improve the resolution and precision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an encoder, and more particularly to an encoder that can be used to encode a linear movement distance or a rotation angle.

[Conventional technology]

Encoders using rotating code disks are known. However, the known encoder has a problem in that the rotation angle of the disk between one [-]-dot transmission position and the adjacent []-dot transmission position is too large, and therefore the resolution is low.

In order to solve this problem, it has conventionally been possible to rotate the code disk through a speed-increasing gear device with a large speed-increasing ratio, or to have multiple tracks and sensors on which markings for encoding are set. Although such structures have been proposed, there are problems in that not only the mechanism becomes complicated but also accuracy, durability, reliability, etc. are reduced. Furthermore, there is no encoder that can directly encode linear movement distance.

[Problem that the invention seeks to solve]

The present invention has been made based on the above-mentioned viewpoint, and its purpose is to minimize the number of movable parts (few < K <
The object of the present invention is to provide an encoder which has a simple structure, is easy to handle, has high resolution and accuracy, and can directly encode linear movement distance.

[Means for solving the problem] Accordingly, the present invention provides a rotating shaft that is rotatably supported by a housing and a lid that covers the housing, and that is in contact with a flat J-pull and rotates. The drive wheel is fixed so that its contact part protrudes from the carrier, and a predetermined interval p is formed around the periphery.
Attach a code disk covering a magnetic mark across the magnetic field. The apparatus is equipped with a magnetic mark detection device for detecting the threat mark on the code disk.

(Function) When the table surface that comes into contact with the drive wheel protruding from the housing moves, the drive wheel rotates around the rotating shaft and rotates the code disk fixed thereto. The magnetic mark on this code disk is detected by a mark detection device placed along the magnetic mark, and depending on the direction of movement of the table, that is, the direction of rotation of the drive wheel, the value can be calculated by adding or subtracting jJIl. It is digitally displayed, and 1 in 11! C number 118 control a1! There is something C that is done.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings. Figure 1 shows an example of a mechanical (1 example) of the present invention.
FIG. 2 is a circuit diagram thereof, and FIG. 3 is an explanatory diagram of the arrangement of marks and hints for encoding.

Therefore, in Fig. 1, 1 is not shown (7)
``Nitorii'' (the casing that can be touched, 2 is the lid, 3 is the code disk, 4
5 is a rotating shaft; 5 is a drive wheel that is brought into contact with and rotated on a table surface 6 that moves relative to the supporting device, and rotates the code disk 3 via the rotating shaft 4; 7 and 8.8 are bearings; 9 1 is a bearing holder, 10 is an electric circuit, 11 is a head for detecting magnetic marks, 12 is a position indicator, 13 is a transparent acrylic plate, 14 is a set screw, 15 is a power supply and an external circuit (not shown) This is a cable connector for connecting with.

The encoder shown here is used, for example, to be attached to various machine tools (to measure the position of machining feed, tool rest, etc.), and the housing 1 supports a machining head such as a milling cutter qH. The table surface 6 serves as a guide surface for the lifting arm.

FIG. 2 shows details of a part of the code disk 3, the electric circuit 10°, the head 11 for detecting the mark 11, and the position indicator 12.

? On the periphery of the No. 9 disk 3, a large number of magnetic marks 3a, 3a are magnetized and formed so as to penetrate the disk 3 at a certain interval p, and these magnetic marks Five heads 11-0.11-2.11-4.11- are arranged so as to sandwich the passage through which the marks 3a and 3a pass.
6.11-8 is provided. Also, in the figure, 16-O1
16-2, 16-4, 16-6, 16-8 are magnetic diodes, 17-0.17-2.17-4.17-6.17
-8 is a resistor, 18 is a power supply circuit, 19-0119-2.1
9-4.19-6.19-8 is an input/output converter, 20 is
1 ma S high stable niremen 1-21-0.21-2
．． 21-4.21-6.21-8 buffer register to 5-bit 1, 22 and 23 are AND circuits, 24 and 251 are monostable elements, 26 is a signal for a seven-segment five-point type numeric display 27 The converter 28 is an up/down counter which together with the numeric display 27 constitutes the position display 12.

Therefore, in this embodiment, the distance between the phases U of the head 11-i (i4 = 0.4, 6.8) is Cp, which is generally as follows. Let n and k be positive integers,
(Formula%Formula%)) The relational expression between D and p will be explained below with reference to FIG.

FIG. 3(A) is a diagram showing the principle of a known vernier.

In the figure, the 4th scale of the main scale 30 is 5'8 minutes,
(Generally, the n-1 or n+1 scale is divided into 11 equal parts)
A scale is applied such that 1 scale of the main scale is 1 yen; (same as above): j: is the product of 1 scale of the vernier scale.
a can be read.

If one attempts to construct an encoder by applying this principle as is, several problems will occur.

That is, in a normal vernier, the scale interval of the vernier is approximately 191 mm (or 20 mm), but in order to align the magnetic mark detection head with this interval, the head must have a small and delicate structure. It is necessary to make it a thing. Then,
If such an attempt is made, not only will the mechanical strength be sacrificed, but the signal output level will also be extremely low, making it impractical. Furthermore, if an attempt is made to widen the head spacing without lowering the resolution using a known method, it becomes necessary to extremely increase the diameter of the code disk 3 and the diameter ratio to the drive wheel 5. However, if this diameter ratio is, for example, 5 to 10 or more, the mechanical quality will be unsatisfactory and practicality will be lost.

Therefore, in the present invention, as shown in FIG. 3(B), the distance between the head centers per m on the scale of the vernier is expressed as n''=1 [)=-□ p 10k (n+1) +1 (in Figure 3, = 1), and without reducing the mechanical strength or output level of the head, the diameter ratio of the diameter of the No. 11 disk 3 and the drive wheel 5 can be increased. It is intended to maintain high resolution and reliability and to maintain high resolution and reliability.

where (n+1)Ill is the spacing between the zero and maximum graduations of the vernier scale, and k is the desired positive integer. For this reason, a vernier J 31 is shown in FIG. 3 (B
) as shown in the figure below.

That is, in the present invention, it corresponds to the main scale 30? The magnetic marks recorded on the disk in the q number are 0.2 on the vernier scale 31,
It is read by magnetic heads installed at positions 4 and 6.8, respectively, and at this time, in the above formula, n
, = 5.1 (-1, then the sign 2 digit H of the vernier scale 31
The magnetic head placed at position O is □p 10k (n -1)1'l = -11+
40 = mounted 4-gp apart. Therefore, the deviation between the head and the main scale scale 5 is <Hll, which is the same as in the case of a known vernier.

Thereafter, magnetic heads are provided at positions 4, 6.8 on the vernier scale at the same intervals, and the head at position 4 and the scale 1 of the main scale.
The deviation from 0 is 50.6 and the main scale scale is 15.
The deviation is 71), and the head at position 8 and the scale of the main scale are 20
The deviation from this is -5-p. Therefore, if the main scale moves to the left by one hundred and one centimeters, the magnetic mark corresponding to scale 5 on the main scale will be detected by the magnetic helmet at position 2 on the vernier scale, and if it moves further by H1l, the main scale will The magnetic mark at eye @10 is detected by the magnetic head at position 4 on the vernier as J2,
Similarly, the Ii magnetic mark on scale 15 of the main scale is detected by the magnetic head at position 6 on the vernier scale, and the magnetic mark on scale 20 of the main scale is detected by the magnetic head at position 8 on the vernier scale. Ru. In addition, if we shift =2 in the above formula,
Also, the number 4 on the vernier scale is located at a position shifted by -g11 from the scale 17 of the main scale toward the O side.

As described above, according to the present invention, even if the magnetic head spacing is set to be much wider, the resolution of
1] which is maintained at 10 as in the case of .

The specifications of the second theta shown in Figures 1 and 2 will be explained in terms of the wing body.

If the diameter ratio of the code disk 3 and the drive wheel 5 is 5, and the interval p between the magnetic marks recorded on the outer periphery of the disk 3 is set to 0.5 mm, then the encoder will be 0.5 mm relative to the measured object.
Every time the code disk 3 moves by 1 m, the code disk 3 is rotated by 1 scale of T degrees. Therefore, in Fig. 3, n=
5, the resolution will be] "-0,05
mm yells. On the other hand, the spacing between each 1-ki head is: When n=5, when k=1, [)=2.4mm When k=2, D=4.4mm When n-10, When −・1, [) −4,85111mk=2
In the throat, D = 9.45 mu.

Therefore, the width W of the magnetic head itself that can be used in C1 ranges from about 2.4 mm to 9.45 mm depending on each of the above cases, which is easily possible at the current technological level.

On the other hand, according to the conventionally known Verni A7 method, as described above, the code circle l! Assuming that the diameter ratio of A3 and drive wheel 5 is 5, and the interval p between the magnetic marks is 0.5 mm, the interval between each magnetic head is 0.4 mm when n = 5, and n =
In the case of 10, it is 0.45 mm, and accordingly, the width W of the magnetic head itself is also 0.4 mm or 0.45 mm.
No matter what, it is actually close to impossible.

Hereinafter, FIG. 2 will be explained again. One of the five magnetic mark detection heads 11-0 to 11-8, for example 11-0 in the illustrated state, detects the magnetic mark 3.
If it is assumed that the current flowing through the magnetic diode 16-0 corresponding to 1 has reached the maximum value, the output of the human output conversion circuit 19-0 will be in state 1. It has become. Note that the outputs of the other input/output conversion circuits 19-2 to 19-8 are in the state 0.

Therefore, five RSs constituting the buffer register 20
Only the back of the bistable element 21-0 is in the 1~ state, and the others are in the 1~ state.

In this state, the output of the signal converter 26 is
This is the output necessary to display the number 0 in 7.
The number display 27 displays the number 0 corresponding to the head 11-0.

As a result, the magnetic disk 3 rotates to the left in FIG. 2, and although the position of the magnetic mark shifts even slightly, the magnetic diode 16-0
The current flowing through the output converter 19-0 decreases and the output of the human power converter 19-0 goes to state 0. 17! The l movement progresses further and the magnetic mark 3a
One of them matches the head 11-2, and the input/output converter 1
The output of 9-2 becomes state 1, and the RS bias staple element 21-0 is reset, and the output of 21-2 becomes state 1.
are selected from 1 to 1, and the number (lf12) is displayed on the numeric display 21.

At this time, Shinosdable 1-Remen 1-24 is 1
- triggered and an output pulse is oscillated, but since the RS bistable elements 1 to 21-8 are in the reset state, this output pulse passes through the AND circuit 23 and j! #Irrrrrrrrrrrrrrrrrrrr.

Thereafter, as the IH>@ disk 3 continues to rotate, the magnetic mark detection heads 11-4.11-6.11-8 sequentially detect magnetic marks in rotation, and the input/output converter 19-4.19- 6.
The output of 19-8 becomes state 1 in turn, and the display on the numeric display 27 sequentially changes to 4, 6.8.

When the code disk 30 rotates further and the head 11-0 detects one magnetic mark again, RSS bistables 1 to 210 are set and 21-8 is reset, so the numbers At the 8th hour, the display on the display 27 changes to O, and the output pulse of the monostable core element 1-25 passes through the AND circuit 22 and is input to the addition input terminal of the up-down counter 28. An additional step is taken in the direction.

1 If the middle matches, the monostable tenth table 1 to 2;) and the AND circuit 22 indicate that the state 1 display position of the buffer register 20 is at the top]. 21-8 to the least significant bit, RS bistable elements 1 to 21-0. t) The addition pulse generation circuit that generates the output pulse is constructed.

Also, when the code disk 3 is switched in the opposite direction to the above, R
After the S bistable element 21-0 changes to the state 1~, the set state of A is transferred to the RS bistable element 21-8, and an output pulse is oscillated from the pull T element 24. The output pulse A passes through the AND circuit 23, enters the subtraction input terminal of the up/down counter 28, and advances it by a subtraction step in the negative direction.

That is, the monostable] Niremen 1-24 and the AND circuit 23 are connected to the state 1 display pins 1 to 1 of the buffer 7 register 20.
constitutes a subtraction pulse generation circuit that generates an output pulse when the bit directly transitions from the least significant bit to the most significant bit.

〔Effect of the invention〕

Therefore, when this encoder is moved back and forth along the table 6 shown in FIG. 1, its position is always displayed on the display 12.

The magnetic material on which the code disk 3 or the magnetic mark of the disk 3 is formed is I-molded steel, which is easy to machine, such as Fe-Cr-G described in Japanese Patent Publication No. 49-20-451, etc.
It is best to use an O-based hard or semi-hard magnet.Also, the magnetic mark is placed on a thinly rolled disk or on the circumferential edge of the disk in a donut shape or radial comb shape. It is formed by magnetizing in the perpendicular front and back directions, and therefore, the detection head has a configuration in which a pair of magnetic poles sandwich the magnetic material on which the magnetic mark is formed, and the detection signal is transmitted from the conventional magnetic mark. Since it can be made significantly larger than in the case of the detection method, the S/N ratio can be improved.

Since the present invention is constructed as described above, the encoder according to the present invention can constitute a practical encoder with high precision and high resolution without using a particularly large diameter code disk or delicate detection head. It's something you get.

It should be noted that the 14 configurations of the present invention are not limited to the above-mentioned embodiments. For example, the 111i mark detection head is
It is not limited to those using Ki-Dia-D,
The known head of the song can be freely used, such as a Hall effect element, etc., and the aspect of the magnetic head can be changed accordingly, and the configuration of the logic circuit is also within the scope of the present invention. It is possible to freely change the setting using known circuit elements, and the display, etc. can be installed separately outside the iQ GJ's housing, or separately from the encoder. It is also conceivable to use the internal or external memory of other devices, such as an computer, and the present invention encompasses all of them.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the mechanical components of an embodiment of the encoder according to the present invention, Fig. 2 is its circuit diagram, and Fig. 3 is an explanatory diagram of the arrangement of marks and sensors for encoding. . 1....... Housing 2... Lid 3... Code disc 4... Rotating shaft 5. ....... Drive wheel 7.8 ...... Bearing 10 ...... Electric circuit 11.11-0.11-2.11-4.11 -6.11
-8......Magnetic mark detection head 12.
......Position indicator 15...Cable connector 16-0. H
i-2...Magnetic diode 18...
......Power supply circuit 19-0.19-2......Input/output converter 2
0...Baranoa register 26...
...Signal converter 27...Numeric display 28...Up/down counter patent
Applicant: I-1 Niji Co., Ltd. ? Pax research' request. 1) Representative I”-Kiyoshi-゛)

Claims (2)

[Claims] (1) A rotary shaft supported rotatably, a drive wheel fixed to the rotary shaft that converts linear motion into rotary motion, and a magnetic mark at a predetermined interval p on the periphery of the rotary shaft. and a magnetic mark detection device provided on the side of a support supporting the rotary shaft via a bearing, which detects magnetic marks on the code disk in contact with each other. An encoder characterized in that the amount of linear movement of a rotating shaft is detected by reading a magnetic mark on a code disk using the magnetic mark detection device. (2) The encoder according to claim 1, wherein the drive wheel rolls with its outer periphery in contact with a flat surface.