JPS6375615A - Number-of-rotation detector - Google Patents

Abstract

PURPOSE:To obtain the title detector having simple constitution such that a transmission loop is constituted of 2<n> transmission elements when the max. number of rotations detected are set to 2<n> and (n) magnetic bubble detectors are arranged in the transmission element. CONSTITUTION:Magnetic bubble detectors D21-D23 correspond to rotor R and the transmission of magnetic bubbles due to the rotation of a driving magnetic field corresponds to the rotation of the rotor R. Therefore, the pattern signals obtained from three detectors D21-D23 correspond to the transmission number of the magnetic bubbles and the number of rotations of the driving magnetic field of a rotary shaft can be detected from said pattern signals. In this transmission state of the magnetic bubbles, the output of the detector D21 is 0 and the outputs of the detectors D22, D23 are 1 and the obtained pattern signals become '011' and, when the driving magnetic field further makes one revolution, the pattern signals change to '111'. As mentioned above, when the bit pattern constituting a memory wheel is formed on a transmission loop D, eight different pattern signals corresponding to the number of rotations of the driving magnetic fields in a ratio of 1:1 are obtained from three detectors D21-D23.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotation speed detector that detects the rotation speed of a single rotating shaft or the like.

More specifically, the present invention relates to a rotation speed detector that operates even when the power supply is interrupted and can always obtain an output corresponding to the rotation speed.

[Conventional technology]

An example of a conventional rotation speed detector of this type is:

There is a device that has already been filed by the applicant of the present application as Japanese Patent Application No. 1986-gNIII. FIG. 5 is a configuration diagram showing an outline of this rotation speed detector. The rotation speed detector shown in the figure includes a magnetic bubble element 3 that sequentially transfers magnetic bubbles according to the rotation of a driving magnetic field, and a rotating shaft 1 that rotates while being attached to a rotating shaft 1 to generate a driving magnetic field for this magnetic bubble element 3. It has a permanent magnet 2, and the number of rotations of the rotating shaft 1 etc. is detected from the position of the magnetic bubble on the transfer pattern in the magnetic bubble element 3. In addition, FIG. 6 shows the magnetic bubble element 3.
This figure shows an example of a transfer pattern in . The transfer pattern shown in the figure is based on what is generally called the TI type, and is composed of three independent transfer loops A to C. H is the driving magnetic field generated by the permanent magnet 2, AI, 81. CI is a pattern for magnetic bubble generation, ^2.82. C2 is a magnetic bubble detector (magnetic bubble detection pattern) made of, for example, a magnetoresistive element.Furthermore, the ○ mark in the figure indicates the position on the transfer loop where the magnetic bubble moves in accordance with the rotation of the driving magnetic field. In the figure, the hatched O mark represents the presence of magnetic bubbles.

Therefore, when the number of poles of the permanent magnet 2 is 2, when the rotating shaft 1 rotates once, the magnetic bubble in the magnetic bubble element 3 moves by one step on the transfer pattern, and the magnetic bubble on the transfer pattern moves by one step. By detecting the position of the bubble, the number of rotations of the rotating shaft 1 can be determined. Note that a 3-bit binary signal corresponding to the rotational speed of the rotating shaft 1 is obtained from the magnetic bubble detectors A2 to C2.

In this way, if the magnetic bubble element 3 is configured to control the transfer of magnetic bubbles by the rotating permanent magnet 2 attached to the rotating shaft 1 etc., even when the power is off, the magnetic bubble element 3 will generate magnetic bubbles even when the power is off. Since this transfer is performed, it is possible to realize a rotation speed detector that operates even when the power source is cut off.

[Problem that the invention seeks to solve]

However, in such a rotation speed detector, in order to obtain a binary signal corresponding to the rotation speed, a transfer loop is configured for each binary digit, so the transfer elements that make up the transfer pattern are cFj: one element is required for one step of i-bubble transfer) is large;
The yield rate during manufacturing becomes poor and the chip size of the magnetic bubble element becomes large.

For example, in the transfer pattern of FIG. 6, 14 transfer elements are required to detect rotation speeds up to 8, but if the M large detection rotation speed is 256 (=2'), The number of transfer loops is 8, and the total number of transfer elements constituting each transfer loop is 510 (approximately 256×2).

The present invention eliminates the drawbacks of the conventional device as described above, reduces the number of transfer elements constituting the transfer loop, improves the yield during manufacturing, and reduces the chip size of the magnetic bubble element. The object of this invention is to realize a rotation speed detector with a simple configuration that can be made small and reduce manufacturing costs.

[Means for solving problems]

The rotation speed detector of the present invention generates a driving magnetic field for a magnetic bubble element using a permanent magnet attached to a rotation shaft, etc., and detects the rotation speed of the rotation shaft from the position of the magnetic bubble on a transfer pattern in the magnetic bubble element. In the rotation speed detector designed to detect, when the maximum detected rotation speed is 2', 2
A transfer loop is configured with ' transfer elements, and n magnetic bubble detectors are arranged in this transfer loop, and
A 2'-digit bit pattern determined by the memory wheel theorem is formed on the transfer loop depending on the presence or absence of magnetic bubbles.

[For production]

In this way, when the bit pattern constituting the memory wheel is formed on the transfer loop, from the n magnetic bubble detectors, 2n
It is possible to obtain different pattern signals, and the driving magnetic field (
The rotation speed of a rotating shaft, etc.) can be easily detected. Therefore, the number of transfer elements constituting the transfer loop can be reduced, the yield during manufacturing can be improved, and the chip size of the magnetic bubble element can be reduced to reduce manufacturing costs.

〔Example〕

Hereinafter, the rotation speed detector of the present invention will be explained using the drawings.

FIG. 1 is a block diagram showing an embodiment of the rotation speed detector of the present invention, and shows an example of a transfer pattern. In the figures, the same parts as in FIGS. 5 and 6 are designated by the same reference numerals. D is a transfer loop, Dl is a pattern for generating magnetic bubbles, and 02n to D23 are magnetic bubble detectors. Note that the transfer pattern shown in the figure is an example of a case where the maximum detected rotation speed is 8 (=2'). That is, the transfer loop D is composed of eight transfer elements, and there are three magnetic bubble detectors in the transfer loop D.
n to D23 are arranged. Further, on the transfer loop D, an 8-digit bit pattern (OIIIIIIIN) determined by the memory wheel theorem is formed depending on the presence or absence of magnetic bubbles.

In general, the S'' type memory wheel has 8 types of symbols S''
When the rotor that touches the following n symbols arranged around the circumference of the ring rotates once, the permutation of n symbols from the 8 symbols appears exactly once. FIG. 2 shows an example of a 23-inch memory wheel. 2
If the decimal bit pattern (0, 1) is arranged as shown in the figure, the 3-digit binary pattern signal obtained according to the rotation of the rotor R will be divided into 8 bits depending on the position (rotation angle) of the rotor R. It can be seen that different patterns are taken, and the position of the rotor R can be discriminated from the state of this pattern signal.

Now, in the device shown in Figure 1, the magnetic bubble detector 08
The opening 23 corresponds to the rotor R, and the transfer of magnetic bubbles due to the rotation of the driving magnetic field corresponds to the rotation of the rotor R. Therefore, three magnetic bubble detectors 0
The pattern signals obtained from 2n to 023 correspond to the number of transferred magnetic bubbles, and the number of rotations of the drive magnetic field (rotation shaft, etc.) can be detected from this pattern signal.

In addition, Figure 3 shows the relationship between the rotation speed of the driving magnetic field and the movement state of the bit pattern on the transfer loop.1For example, the positions of the lower three digits in the figure are magnetic bubble detectors 02n.
~D23 has been detected.

That is, in the transfer state of the magnetic bubble shown in Figure 1,
The output of the magnetic bubble detector [12n is 0, the outputs of the magnetic bubble detectors 0712 and D23 are 1, and the resulting pattern signal is "011".

Further, when the drive magnetic field makes one more rotation, the pattern signal changes to "111".

When the bit pattern constituting the memory wheel is formed on the transfer loop D in this way, three magnetic bubble detectors 112n~! 123, it is possible to obtain eight different pattern signals that correspond one-to-one to the rotational speed of the driving magnetic field. Therefore, compared to the conventional method as shown in FIG. Manufacturing costs can be reduced by reducing the chip size of the element.

In this case, the number of transfer elements that can be reduced is 6, but if the detected rotation speed increases, the reduction rate will be approximately 1.
/2, which increases the effect.

Now, in the above explanation, the maximum detected rotation speed P is 8 (
1''), but the value of P is not limited to 2''. For example, when P=6, 22-1<P
Since ≦2n, similar detection can be performed by constructing the transfer pattern with a six-element transfer loop and three magnetic bubble detectors and slightly modifying the bit pattern formed on the transfer loop. FIG. 4 shows a modification of the bit pattern of FIG. 3 for six elements. Further, in the above description, the case where a plurality of magnetic bubble detectors are arranged at consecutive positions on the transfer loop is exemplified, but the positions of the magnetic bubble detectors do not necessarily have to be consecutive.

- It is suitable for realizing a multi-rotation encoder by combining it with an encoder that can obtain a precise measurement output.

That is, by detecting the rotation speed of the rotating shaft etc. with the rotation speed detector of the present invention and also detecting the rotation angle of 0 to 360 degrees with the encoder, it is possible to detect the rotation angle of the rotating shaft etc. by the encoder, even if the t source is blocked during measurement. Also, it is possible to realize a multi-rotation encoder that can always obtain absolute measurement output.

〔Effect of the invention〕

As explained above, in the rotation speed detector of the present invention, a driving magnetic field for a magnetic bubble element is generated by a permanent magnet attached to a rotating shaft, etc. In a rotation speed detector designed to detect the rotation speed of a shaft, etc., when the maximum detected rotation speed is 2'', a transfer loop is constructed with 2n transfer elements, and n magnetic bubbles are formed in this transfer loop. Since the detector is arranged and formed on the transfer loop according to the memory wheel theorem,
From the n magnetic bubble detectors, 2" different pattern signals corresponding one-to-one to the rotation speed of the driving magnetic field can be obtained, making it possible to reduce the number of transfer elements configuring the transfer loop, and reducing the number of transfer elements during manufacturing. It is possible to realize a rotation speed detector with a simple configuration, which can improve the yield, reduce the chip size of the magnetic bubble element, and reduce manufacturing costs.

[Brief explanation of the drawing]

1 to 4 are block diagrams showing one embodiment of the rotation speed detector of the present invention, and FIGS. 5 and 6 are block diagrams showing an example of a conventional rotation speed detector. 1...Rotating shaft, 2...Permanent magnet, 3.
...Magnetic bubble element, A-D...Transfer loop, A1-DI...Pattern for magnetic bubble generation, A2-C2,02n-D23...Magnetic Bubble detector, H... Drive magnetic field, R...
・Rotor. Volume 1 Figure D2n D22 D23 3 10100011 ← 4 Taiasahi s 1o as shown
ooi 1 i. D2n D22023,! , 000111 Ivy 5

Claims (1)

[Claims] A rotational speed detector that generates a driving magnetic field for a magnetic bubble element using a permanent magnet attached to a rotating shaft, etc., and detects the rotational speed of the rotating shaft, etc. from the position of a magnetic bubble on a transfer pattern in the magnetic bubble element. When the maximum detection rotation speed is 2^n, a transfer loop is constructed with 2^n transfer elements, n magnetic bubble detectors are arranged in this transfer loop, and it is determined by the memory wheel theorem. A rotation speed detector characterized in that a 2^n-digit bit pattern is formed on the transfer loop depending on the presence or absence of magnetic bubbles.