JPH04147009A - Multirotation type absolute-value rotary encoder - Google Patents

Abstract

PURPOSE:To enable precise detection of the number of revolutions by providing a magnetic member rotating with a rotating shaft and also a magnetic sensor constructed by winding a coil on an amorphous magnetic body. CONSTITUTION:When a rotary disk 13 is rotated with a rotating shaft 1, a light emitted from a light-emitting element 5 is sensed by a light-sensing element 6 through a slit of the disk 13, a code value of the slit is read, and in an absolute rotational angle detecting circuit 8, an absolute angle of the rotating shaft 1 is detected from an electric signal from the element 6. Besides, a magnetic member 2 is rotated with the rotation of the rotating shaft 1, a magnetic field of an amorphous magnetic body 3 is inverted with the rotation of the rotating shaft 1 and a pulse is generated in a coil 4. This pulse signal is counted by a revolution number recognition circuit 7 and the number of revolutions of the rotating shaft 1 is recognized. When a power switch 12 is put in an OFF state, a power is supplied only to a magnetic encoder part from a battery 10 and the number of revolutions of the rotating shaft 1 can be detected in the circuit 7. In a multirotation absolute rotational angle generating circuit 9, an absolute rotational angle corresponding to multirotation is outputted on the basis of signals obtained from the circuits 7 and 8.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a multi-rotation type absolute value rotary encoder for detecting the absolute rotation angle of a rotating body. The methods can be roughly divided into the following two types.

One is to build a speed reduction mechanism into a single-turn absolute value rotary encoder to make it into a multi-rotation type, and the other is to add a pulse counter to an incremental encoder so that when the power is turned off (, There are two methods for storing the count number. Asahi has the disadvantage that the absolute rotation angle cannot be determined when pulse misses occur due to noise, etc. Therefore, we have recently developed an encoder that consists of a single string type absolute value encoder, an incremental encoder with 1 pulse per rotation, and a counter that counts the pulses of the incremental encoder. A method has been developed in which an external battery stores the number of incremental pulses corresponding to the number of rotations.

The single string absolute value encoder (i
Photoelectric method, magnetic method, and resolver method each have their own characteristics and can be used depending on the application.Also, if the rotating shaft rotates several times when the power is turned off, the absolute rotation angle cannot be determined. I need to remember. Therefore, the incremental encoder used in the multi-string absolute value encoder is battery-powered when the power is turned off. Therefore, if the life of the external battery is infinite, it can be considered an absolute value encoder. GAa Photoelectric method (Table 1) A light emitting element and a light receiving element are arranged through a slit plate, and as a current is required to flow through the light emitting element in principle, it has the problem that it is not suitable for power saving. There are reports of success in reducing power consumption by adopting a method using a magnetoresistive element, which is one of the magnetic methods. Machine vo1.204 p,
252 (1989° No. 3)) Problems to be Solved by the Invention However, the above-mentioned conventional multi-rotation type absolute value rotary encoder using a magnetoresistive element requires a magnet to apply a bias magnetic field to the magnetoresistive element. However, in order to further extend the battery life, magnetic Sumo wrestlers need to save power by increasing the resistance value of the resistive element, which has problems such as decreased detection sensitivity, increased volume, and increased cost.

The present invention solves these conventional problems,
It is an object of the present invention to provide an excellent multi-rotation type absolute value rotary encoder that has a simple structure, has good temperature characteristics, and is even more power-saving than a system using a magnetoresistive element.

Means for Solving the Problems The present invention (in order to achieve the above objects) provides an absolute value rotary encoder that detects the absolute rotation angle of one rotation of a rotating shaft, and a magnetized member that rotates with the rotating shaft and has a plurality of magnetic poles. , an amorphous magnetic material disposed at a predetermined distance from the magnetizing member, and a coil that is wound several times around the amorphous magnetic material and extracts a pulse-like signal generated when the magnetization of the amorphous magnetic material is reversed. The invention is configured to detect the number of rotations by counting pulse signals.The present invention has the following effects due to the above-described structure.That is, as the rotating shaft rotates, the magnetic poles on the magnetized member rotate. As it rotates, the magnetic field applied to the amorphous magnetic material changes.Amorphous magnetic material has the property that the magnetization inside the magnetic material reverses or changes rapidly when a predetermined demagnetizing field is exceeded, so it is picked up by the amorphous magnetic material. If a coil is provided, a pulse-like signal can be obtained, and by counting these pulses, the rotation speed of the rotating shaft can be detected with low power.

Therefore, according to the present invention +! By providing a magnetic member that rotates together with the rotating shaft and a magnetic sensor that includes a coil in an amorphous magnetic material, it is possible to detect the rotational speed of the rotating shaft with less power consumption. Furthermore, since the structure is simple, it is suitable for miniaturization, and since the amorphous magnetic material has good temperature characteristics, it has the effect that the rotation speed can be detected with high accuracy.

EXAMPLE A multi-rotation type absolute value encoder according to an embodiment of the present invention will be described below with reference to the drawings, but FIG. 1 shows an embodiment of the present invention. It is a magnetic member, magnetized into two poles, and attached to the rotating shaft 1. A coil 4 is wound around the amorphous magnetic material 3 and is attached to the magnetic member 2 through a predetermined gap.Also, the signal detected by the coil 4 is input to the rotation speed recognition circuit 7 to determine the rotation of the rotating shaft 1. Even though the rotating disk 13 is attached to the rotating shaft 1, the light emitted from the light emitting element 5 passes through the rotating disk 13 and enters the light receiving element 6. Absolute rotation angle detection circuit 8 (Y) outputs the absolute rotation angle of the rotary disk 13 from the electric signal obtained from the light receiving element 6a. Outputs an absolute rotation angle signal corresponding to multiple rotations from the rotation speed and the absolute rotation angle of the rotating shaft 1 obtained from the absolute rotation angle detection circuit 8.Power supply 11 i;L
Power is supplied to the optical encoder section and the electric circuit of a part of the magnetic encoder via the power switch 12. Although the battery 10 supplies power only to the magnetic encoder section through a diode, the operation of the above embodiment will now be described. The above embodiment ζ
Although it basically consists of a magnetic encoder section and an optical encoder section, the optical encoder section 11 is an example of a commonly used single-rotation type optical absolute value encoder, and its operation will be explained below. At the same time as the rotating shaft 1 rotates, the rotating disk 13 rotates. There is a slit on the rotating disk I3 (upper).
Even if the slit shape is processed with a predetermined code (for example, a gray code) in the circumferential direction, the light emitted from the light emitting element 5 (passes through the slit of the rotating disk 13 and enters the light receiving element 6, so the electrical signal obtained from the light receiving element 6 is The code value of the slit can be read.Rotating disk 1
Since the code value processed into 3 is processed so that no one is the same, the absolute angle of the rotation axis 1 can be detected from the electric signal obtained from the absolute rotation angle detection circuit 8 (light receiving element 6). The detection capability of an optical absolute value encoder is in principle within a range of 360 degrees, and cannot recognize absolute rotation angles of one revolution or more.

Therefore, a method has been considered in which the number of rotations is counted in increments and the count value is stored in a battery even if the power supply is cut off. With this method, even when the power is turned on again, even if the absolute rotation angle is 360 degrees or more, it can be recognized.

However, when the power is stopped, it is possible that the rotating shaft 1 may rotate due to an external force, etc., so the number of rotations of the rotating shaft 1 is detected and counted in addition to storing the count value corresponding to the number of rotations even when the power is stopped. Therefore, the encoder that recognizes the rotation speed needs to have low power consumption. However, the photoelectric encoder ζ is not suitable for low power consumption applications because current must always flow through the light emitting element. Therefore, as shown in FIG. 1, in this embodiment, a magnetic member 2 and an amorphous magnetic material 3 constitute an incremental encoder, and a rotation speed recognition circuit 7 detects and stores the rotation speed of rotation #1. The second figure is
This figure shows an example of a magnetic sensor using an amorphous magnetic material 3.A magnetic sensor (composed of an amorphous wire 3 as an amorphous magnetic material and a coil 4 wound several times around the amorphous wire 3) is placed at the center of a coil bobbin 21. An amorphous wire 3 is inserted, a coil 4 is wound around a coil bobbin 21, and the outer circumferential side is covered with epoxy resin 22.In this way, a magnetic sensor using an amorphous magnetic material 3 can be created by simply winding a coil around the wire. It has a simple configuration, which is effective in downsizing the equipment.In Fig. 1, when the rotating shaft l rotates, the magnetic member 2, which is magnetized into two poles, rotates together with the rotating shaft 1.The magnetic member 2 rotates. Then, the magnetic field of the amorphous magnetic material 3 will be reversed as the rotating shaft 1 rotates.When the magnetic field in which the amorphous magnetic material 3 is placed is reversed, the magnetization inside the amorphous magnetic material will rapidly change. Since it has the property of reversal, a pulse is generated in the coil 4. This property i
It is possible to obtain a steep pulse signal even with a weak magnetic field of about 10[○e], and it is also possible to accurately detect changes in the magnetic field generated from the magnetic member 2 regardless of whether it is fast or slow.
Further, the pulse signal is generated by reversing the magnetization of the amorphous magnetic material 3, and since the pulse signal can be generated without power supply, it goes without saying that power is basically saved. However, the temperature characteristics of the L amorphous magnetic material 3 are good, and the characteristics do not deteriorate due to temperature changes. By counting the pulse signals thus obtained by the rotation speed recognition circuit 7, the rotation speed of the 4J rotating shaft 1 can be recognized.

Furthermore, when the power switch 12 is turned off, power is supplied from the battery 10 only to the magnetic encoder section.
Therefore, even when the power is stopped, power is supplied to the rotation speed recognition circuit 7 and the rotation speed of the rotating shaft 1 can be detected. When the power switch 12 is in the human state, power is supplied from the power source 11 to the magnetic encoder section and the optical encoder section, and the optical encoder can detect an absolute angle in a range of 360 degrees. Multi-rotation absolute rotation angle generation circuit 9 i:L An example of outputting the absolute rotation angle corresponding to multiple rotations from the signal obtained from the rotation speed recognition circuit 7 and the signal obtained from the absolute rotation angle detection circuit 8.
Assuming that the rotation speed detected by the rotation speed recognition circuit 7 is n rotations and the absolute rotation angle detected by the optical encoder is k,
Multi-rotation absolute rotation angle generation circuit 9ζ, t 360xn+k
It generates a signal corresponding to [degrees].

In this embodiment, the magnetic member 2 and the rotating disk 13 are separate members (the same effect can be obtained even if the magnetic member is attached to a part of the rotating disk.
is magnetized by 2 times (the magnetization pattern of the magnetic member 2 is such that the amorphous magnetic material 3 is magnetized at least once per rotation).
It is good as long as it can reverse the magnetization by 1 times (°C
Furthermore, although this embodiment has been described using a photoelectric absolute value encoder, it goes without saying that any absolute value encoder that can recognize the absolute rotation angle within the range of 360 [l, x] will suffice.

Effects of the Invention As is clear from the above embodiments, the present invention provides an incremental encoder equipped with a magnetic sensor using an amorphous magnetic material, a rotation speed recognition circuit that recognizes the rotation speed from a signal obtained from the incremental encoder, and a power supply stoppage. Equipped with a power supply means to supply power to the rotation speed recognition circuit and an absolute value encoder that can detect absolute angles within the range of one rotation, the rotation speed can be detected with low power consumption even when the power is turned off, and battery life is conserved. It has the advantage of being long, and allows you to know the absolute rotation angle of the rotating shaft even if the rotating shaft rotates many times. Since the magnetic sensor using an amorphous magnetic material has a simple configuration, it is advantageous in making the device smaller and at low cost. Furthermore, since the amorphous magnetic material has good temperature characteristics, it has the effect of being able to accurately detect the rotational speed of the rotating shaft even in the face of temperature changes. Also, amorphous magnetic material ζ
Since the detection sensitivity is good, the rotation speed can be detected with high accuracy.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of a multi-rotation type absolute value encoder according to an embodiment of the present invention. FIG. 2 is a sectional view of a magnetic sensor using an amorphous magnetic material. 296. magnetized member, 311. Amorphous magnetic material 71
01 rotation speed recognition times i 10. ,, Batch 1 Name of agent Patent attorney Akira Okaji and 2 others Figure

Claims (1)

[Claims] (1) A multi-rotation type absolute value rotary encoder that outputs a value corresponding to the absolute rotation angle even if the rotating shaft rotates many times, the absolute value rotary encoder detecting the absolute rotation angle for one rotation of the rotating shaft. a magnetized member that rotates with the rotating shaft and has a plurality of magnetic poles magnetized; an amorphous magnetic material disposed at a predetermined distance from the magnetized member; a coil that extracts a pulse-like signal generated when a body's magnetization changes; a rotation-speed recognition circuit that detects and stores the rotation speed of the rotating shaft from the pulse-like signal obtained from the coil; A multi-rotation type absolute value rotary encoder characterized by comprising: power supply means for supplying power to a recognition circuit.