JP2008014799A - Absolute value encoder device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly-reliable absolute value encoder device capable of detecting and holding a multiple rotation quantity without power supply from the outside when a main power source is shut off, and dispensing with a mechanical contact part for detecting the multiple rotation quantity. <P>SOLUTION: A permanent magnet 7 bipolarized in the plane direction of a rotary disk 5 is loaded on the rotary disk 5. A power generation device 2 comprising a magnetic wire 2a having a large Barkhausen effect and a coil 2b wound around the wire is loaded on a circuit board 19. When the main power source is shut off, the multiple rotation quantity is counted by operating magnetometric sensors 8a, 8b, comparators 9a, 9b and an unillustrated a multiple rotation detection operation processor, by using a voltage generated in the coil by the large Barkhausen effect. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an encoder device that detects a rotational position of a motor used in industrial robots, NC machine tools, and the like, and in particular, an absolute value encoder device that detects a multi-rotation amount in addition to detecting an absolute position of an angle within one rotation. About.

(Conventional example 1)
Conventionally, there has been disclosed an absolute value encoder provided with a counter circuit that counts a multi-rotation amount using electrical energy converted by a power generator and stores this count. (See Patent Document 1).
FIG. 14 is a partial front view of the absolute value encoder in the first prior art. FIG. 15 is a side cross-sectional view including the main body of the absolute encoder taken along the line AA in FIG.
In the figure, the tip of the rotating body 9 is provided with two claw portions 21, and the tips of the two claw portions 21 are configured so as to be positioned concentrically when rotating with the rotation of the rotary shaft 3. Has been.

  Further, between the disc scale 5 and the rotating body 9, for example, a support plate 23 as a fixing portion for fixing various members is positioned outside the outer peripheral surface at the right end of the collar 7, and the rotating body. 9 is attached to the main body 25 of the encoder 1 so as not to interfere. On the right side surface of the support plate 23 in FIG. 15, for example, a leaf spring 27 as an elastic body capable of repelling the tip of the claw portion 21 on the rotation locus of the claw portion 21 of the rotator 9 is positioned around the rotator 9. The elastic body holding part 29 is provided.

  A hammer 33 constituting a part of the power generation device 31 is provided on one surface of the front end side of the leaf spring 27, and a piezoelectric element 35 constituting a part of the power generation device 31 is provided at a position facing the hammer 33. ing.

  With the above configuration, when the rotating shaft 3 and the rotating body 9 rotate in the direction of the arrow in FIG. 14, the plate spring 27 is repelled in the state where the tip of the claw portion 21 is hooked on the tip of the plate spring 27. As shown by the chain line, the repulsive force is accumulated in the leaf spring 27 by warping in the direction opposite to the piezoelectric element 35. When the rotating body 9 further rotates, the tip of the claw portion 21 comes off so as to be repelled from the tip of the leaf spring 27, so that the leaf spring 27 is moved by the accumulated repulsive force and the hammer 33 of the leaf spring 27 is piezoelectric. Clash with element 35. The impact force applied to the piezoelectric element 35 generated at this time is converted into electric energy by the piezoelectric element 35 by converting the movement energy (kinetic energy) of the leaf spring 27 to generate electric power.

  The elastic body holding portion 29 may be a simple bracket for fixing the base side of the leaf spring 27 to the support plate 23. However, when the encoder 1 is energized, the counter circuit 37, which will be described later, is powered on, so there is no need to generate power by the piezoelectric element 35 as the power generation device 31 of the present embodiment. When the spring 27 is attached to the bracket, the piezoelectric element 35 is struck thousands or tens of thousands of times by the hammer 33 of the leaf spring 27 while being always bounced by the claw portion 21 of the rotating body 9. . For this reason, the service life of devices such as the tip of the leaf spring 27, the hammer 33, and the piezoelectric element 35 is shortened.

  In order to avoid this, in a state where the encoder 1 is energized, even if the rotary shaft 3 of the encoder 1 is rotated by some external force, the leaf spring 27 is retracted to a position where it is not caught by the claw portion 21. Since the configuration is such that the tip of the leaf spring 27, the hammer 33, and the piezoelectric element 35 do not operate, the life of the apparatus is extended.

FIG. 16 is a block diagram of an electronic circuit unit in the first prior art.
The encoder 1 is provided with, for example, an electronic circuit unit 53 as a control device, and is provided with a power storage circuit 55 that charges the power generated by the piezoelectric element 35, and the charge charged in the power storage circuit 55 is countered. A smoothing circuit 57 for supplying power to the circuit 37 is provided.

  The counter circuit 37 includes a reset unit 59, a counter logic unit 61, and a nonvolatile memory unit 63. The reset unit 59 initializes the counter logic unit 61. The counter logic unit 61 calculates a new count value after reading the memory of the nonvolatile memory unit 63, and inputs the calculated value to the nonvolatile memory unit 63. It is what you want to do. The nonvolatile memory unit 63 stores an input value from the counter logic unit 61 and does not require a power source.

  When power is supplied to the counter circuit 37 via the smoothing circuit 57, the counter logic unit 61 is first initialized by the operation of the reset unit 59. Next, the counter logic unit 61 reads the current multi-rotation amount value stored in the nonvolatile memory unit 63. Next, the multi-rotation amount value is set to +1 or -1 by the counter logic unit 61, and a new count value is calculated. The calculated new count value is written back from the counter logic unit 61 to the nonvolatile memory unit 63 and stored.

  Thus, the absolute value encoder of the first prior art is provided with a claw portion at the tip of a rotating body that is mounted on a rotating shaft and rotates, and an elastic body is provided at a part of the fixed portion on the rotation locus of the claw portion, A power generation device that converts the elastic body's moving energy generated by the repulsive force of the elastic body that is bounced and accumulated in the claw into electrical energy is provided, and the amount of multiple rotations is counted using the electrical energy converted by this power generation device. In addition, the multi-rotation amount is detected by providing a counter circuit for storing the count amount.

(Conventional example 2)
As Conventional Example 2, an encoder using a large Barkhausen effect is disclosed. (See Patent Document 2).
FIG. 17 is a diagram showing the configuration of the detection unit and the output signal waveform of the encoder in the second prior art.
In FIG. 17 (a), magnets 200 and 300 are embedded on a rotation circle centered on the rotation axis 0-0 of the rotating body 1 so that the magnetic poles N and S are opposite to each other. Sensors 400 and 500 are installed at right angles to the surface at a predetermined distance from the rotation circle.
The sensors 400 and 500 are installed with a distance difference corresponding to a phase difference in the circumferential direction of the rotating circle with respect to the magnets 200 and 300, and are, for example, coils wound around an amorphous metal wire. Accordingly, the signals PA 1 and PB having the phase difference φ shown in FIG. 17B are obtained by using the Barkhausen jump generated according to the magnetic flux change intersecting the sensors 400 and 500. The signals PA and PB are differential waves that alternately repeat positive and negative, and are triggered by the rising and falling edges of this differential wave to generate a pulse having a predetermined pulse width. The phase time difference of time difference ΔT shown in FIG. A and B pulses for forward / reverse rotation detection having the above can be obtained.

As described above, the encoder of the second prior art obtains the A and B pulses for detecting forward and reverse rotations using the sensor using Barkhausen jump.
(Conventional example 3)

As Conventional Example 3, another example of an encoder using the large Barkhausen effect is disclosed. (See Patent Document 3).
FIG. 18 is a perspective view showing a configuration of a detection unit of an encoder in the third prior art.
In FIG. 18, the permanent magnet 230 is formed in a substantially cylindrical shape, and is joined and attached to a rotating plate 200 that rotates in a predetermined rotation direction. Since the permanent magnet 230 is magnetized with the S pole on the joint surface side with the rotating plate 200 and the N pole on the opposite surface side, the magnetic flux Φ penetrating the inside is orthogonal to the rotating plate 200. .

  The sensor coil 220 is formed by winding a coil wire 220 around an iron core 210 made of an amorphous magnetic material having a Barkhausen effect, and the axial direction of the iron core 210 follows the rotation direction of the rotating plate 200. In detail, it arrange | positions so that it may become a tangential direction which touches a rotation direction.

Next, this operation will be described below with reference to FIGS. 19 (a) and 19 (b).
In the state of FIG. 5A, the permanent magnet 230 is located on the one end 220a side of the sensor coil 220, and the magnetic flux Φ generated from the permanent magnet 230 is from the one end 220a side to the other end 220b side of the sensor coil 220. Pass through the iron core 210. Here, when the rotating plate 200 rotates in a predetermined direction to reach the state shown in FIG. 5B, the permanent magnet 230 is located on the other end 220b side of the sensor coil 220 and is emitted from the permanent magnet 230. The magnetic flux Φ passes through the iron core 210 from the other end 220b side of the sensor coil 220 to the one end 220a side. As described above, the direction of the magnetic flux Φ passing through the iron core 210 of the sensor coil 220 is reversed when the permanent magnet 230 is rotated together with the rotating plate 200, and accordingly, a pulse signal is generated between both ends of the coil wire 220 according to the reversal. Is output, and the rotation state of the rotating plate 200 is detected based on the pulse signal.

As described above, the third prior art encoder uses a sensor in which a permanent magnet is attached to a rotating plate and a coil wire is wound around an iron core made of amorphous magnetic material having a Barkhausen effect, and the axial direction of the iron core is rotated. Based on the pulse signal between both ends of the coil wire that is generated when the direction of the magnetic flux Φ passing through the iron core of the sensor coil is reversed when the permanent magnet rotates with the rotating plate. The rotation state of the rotating plate was detected.
Japanese Patent Laid-Open No. 2002-131087 Japanese Patent Laid-Open No. 10-267951 JP 2000-161989

In the absolute value encoder shown in the conventional example 1, since there is a contact portion between the claw portion and the leaf spring, there is a possibility of breaking, and there is a problem in reliability. In addition, when the power is turned off during high-speed rotation, there is a possibility that the multi-rotation amount is erroneously detected because there is a possibility of rotation before the pawl portion and the leaf spring portion are contacted.
In the encoders using the Barkhausen effect shown in the conventional examples 2 and 3, the rotational direction and rotational speed of the rotating shaft can be detected, but the absolute value of the rotational angle including the multiple rotation amount of the rotating shaft can be detected. There was a problem that I could not.

  The present invention has been made in view of such problems, and its purpose is to detect and hold a multi-rotation amount without power supply from the outside when the main power is cut off, and to detect the multi-rotation amount. An object of the present invention is to provide a highly reliable absolute value encoder device having no mechanical contact portion.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 is an absolute value encoder comprising an absolute position detector for detecting an absolute position within one rotation of the rotating shaft and a multi-rotation detector for detecting multi-rotation. Comprises a permanent magnet provided at the tip of the rotating shaft, a magnetic wire and a coil having a large Barkhausen effect, and provided at a position where the magnetic field of the permanent magnet can be detected. The power source of the multi-rotation detector is backed up by a voltage generated from the power generation device.
According to a second aspect of the present invention, the multi-rotation detector includes a magnetic field detection sensor that outputs two pulse signals having a phase difference, and one of the two pulse signals is generated during power generation by the power generation device. The magnetic field detection sensor is arranged to change to high or low.
The invention according to claim 3 is an absolute value encoder comprising an absolute position detector for detecting an absolute position within one rotation of the rotating shaft and a multi-rotation detector for detecting multi-rotation. Is composed of a permanent magnet provided at the tip of the rotating shaft, a magnetic wire and a coil having a large Barkhausen effect, and is provided at a position where the magnetic field of the permanent magnet is detected and the generated voltages have a phase difference from each other. Two power generators are provided, the power of the multi-rotation detector is backed up by the voltage generated from the power generator when the external power supply is shut off, and the amount of multi-rotation is counted by counting the voltage from the two power generators Is detected.
The invention described in claim 4 is characterized in that a protective circuit for preventing an overvoltage and a reverse voltage generated by the power generation device is provided between the power generation device and the power supply switching device.
According to a fifth aspect of the present invention, the power generation device is characterized in that a plurality of magnetic wires having a large Barkhausen effect are arranged at a certain interval, and a coil for generating an induced voltage is disposed around the magnetic wires.

According to the first aspect of the present invention, when the external power supply is shut off, the power source of the multi-rotation detector is backed up by the power generation device composed of the magnetic wire and coil having a large Barkhausen effect. Therefore, it is possible to provide a highly reliable absolute value encoder device that can detect and hold a multi-rotation amount without supplying power and that there is no fear of mechanical damage because there are no parts to contact.
According to the invention described in claim 2, the magnetic field detection sensor is arranged so that one of two pulse signals obtained by shaping the detection signal from the magnetic field detection sensor changes to high or low during power generation of the power generation device. By doing so, since the rotational displacement and the rotational direction of the rotating shaft can be detected during power generation, it is possible to prevent a miscount of multiple rotation amounts and to provide a highly reliable absolute value encoder device.
Further, according to the invention described in claim 3, when the external power supply is shut off, the power supply of the multi-rotation detector is backed up by the power generation device composed of a magnetic wire and a coil having a large Barkhausen effect. However, the amount of multiple rotations can be detected and held without supplying power from the outside, there is no risk of mechanical damage because there are no parts to contact, and the multiple rotation detection uses the power generation voltages of the two power generators. The rotation detection sensor can be eliminated and the number of parts can be reduced.
According to the invention described in claim 4, if a protection circuit for preventing an overvoltage and a reverse voltage generated by the power generation device is provided between the power generation device and the power supply switching device, the power supply switching device is detected from the overvoltage and the negative voltage. An absolute value encoder device that can be protected and is highly reliable can be provided.
According to the invention described in claim 5, if a plurality of magnetic wires having a large Barkhausen effect are arranged at a certain interval and a coil for generating an induced voltage is arranged around the magnetic wires, the power generation time of the power generator can be reduced. Since the length can be increased, the reliable detection of the multi-rotation detection and the operation of the processing circuit are performed reliably, and the reliability of the absolute value signal data can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view showing the configuration of the absolute value encoder apparatus in the first embodiment of the present invention.
In FIG. 1, 1 is an absolute value encoder, 2 is a power generator, 3 is a rotating shaft, 4 is an encoder stator fixed to the rotating shaft, 5 is a rotating disk fixed to the rotating shaft, and 6 supports the rotating shaft. Bearings 7, permanent magnets arranged on a rotating disk for multi-rotation detection, 8 a and 8 b magnetic field detection sensors for multi-rotation detection, and 9 a and 9 b pulse signals from the magnetic field detection sensors. Comparator for conversion, 15 is a light source such as an LED or laser that irradiates light to the rotating shaft to detect the absolute value within one rotation of the shaft, and 17 is irradiated by the light source 15 and receives the light transmitted through the rotating disk. Although not shown, a light receiving element that converts an electric signal is provided with a fixed slit on the surface of the light receiving element. Reference numeral 19 denotes a circuit board on which sensors 8a, 8b, 9a, 9b, 17 and the like, sensors, power generation devices, signal processing circuits, cables for data transmission / reception and power supply with a host, and the like are mounted.

The absolute value within one rotation is formed by vapor-depositing a gray code light-transmitting and light-shielding slit pattern on the rotating disk 5, and the light passing through the pattern is converted into an electric signal by the photodiode 17, and is shown in FIG. It is obtained by performing arithmetic processing in the one-rotation absolute value arithmetic processing unit 19d shown in the block diagram.
There are several methods for the slit pattern. In addition to the gray code, there are a method in which a random pattern is formed on one track and a method in which a vernier pattern is formed.

The amount of multi-rotation is such that a permanent magnet 7 for multi-rotation detection is fixed to a position where light of the rotating disk 5 is not irradiated by a method such as adhesion, and this magnetic field is detected around the permanent magnet 7 so as to face the permanent magnet 7. Magnetic field detection sensors 8a and 8b are arranged and detected by this signal.
The permanent magnet 7 is two-pole magnetized in the plane direction of the rotating disk 5. As a material of this magnet, a magnet having a relatively strong magnetic force such as a neodymium magnet is preferable, and the magnetic field is set to be about several tens Oe in the vicinity of the power generation device 2.

  The magnetic field detection sensors 8a and 8b are arranged at relative positions where a detection waveform having a phase difference of about 90 degrees is obtained. The magnetic field detection sensor is connected to the circuit board 19 with a lead directly soldered or connected by a lead wire. Since the output signals of the magnetic field detection sensors 8a and 8b are analog signals, they are converted into pulse signals by a comparator or the like. The magnetic field detection sensor may output a pulse signal using an analog pulse conversion process incorporated in one package such as a Hall IC. The pulse signal is input to the multi-rotation detection arithmetic processor 19b shown in FIG. 3, and the multi-rotation amount is counted.

The power generator 2 is mounted at a position where the magnetic field of the permanent magnet 7 on the circuit board 19 is about several tens of Oe. The power generation device 2 has a magnetic wire 2a having a large Barkhausen effect and a coil 2b around the magnetic wire 2a, and the magnetization of the magnetic wire 2a is reversed by a steep domain wall movement caused by the large Barkhausen effect. An induced voltage is generated in the circuit.
When the main power supply is OFF, the magnetic sensors 8a and 8b, the comparators 9a and 9b, and the multi-rotation detection arithmetic processor 19b are operated using the voltage generated by the power generator 2, and the multi-rotation amount is counted.

FIG. 2 is a block diagram illustrating the operation of the power supply switching device that selects the voltage from the power generation device 2 and the voltage from the outside.
The power switch 19a switches between the induced voltage generated in the coil 2b of the power generator 2 and the main power. When the main power is ON, the power switch 19a generates the induced voltage generated in the coil 2b of the power generator 2. The power supply (Vc) to the sensor and the circuit for detecting the multi-rotation amount is outputted from the main power supply. When the main power supply is OFF, the main power supply is cut off, and the induced voltage generated in the coil 2b of the power generation device 2 is output as it is without being cut off.

  At this time, it has a function of detecting that the main power supply has been cut off and transmitting a main power supply OFF detection signal to the multi-rotation processor 19b before the main power supply falls below the operating voltage range of the power supply switch 19a.

FIG. 3 is a block diagram showing the absolute value signal processing in the first embodiment.
The detection signals of the magnetic field detection sensors 8a and 8b are converted into pulse signals by the comparators 9a and 9b and input to the multi-rotation detection arithmetic processor 19b.
The magnetic field detection sensors 8a and 8b, the comparators 9a and 9b, the multi-rotation detection arithmetic processing unit 19b, and the multi-rotation amount count value storage device 19c necessary for counting the multi-rotation amount are connected to Vc, and other processing. The one-turn absolute value arithmetic processor 19d and the absolute value arithmetic processor 19e, which are the devices, are connected to the main power supply voltage Vmain.

First, the operation when the main power supply is turned on and off is explained.
When the main power is ON, the multi-rotation detection calculation processor 19b reads the multi-rotation amount count value data from the multi-rotation amount count value storage device 19c and counts the multi-rotation amount using the pulse signals from the comparators 9a and 9b. To do. At this time, the multi-rotation amount count value may be increased or decreased when the absolute value of one rotation reaches the zero position without using the pulse signals from the comparators 9a and 9b.

  When the main power is turned off, the multi-rotation amount count value held by the multi-rotation detection arithmetic processor 19b until then is stored in the multi-rotation amount count value storage device 19c.

  The absolute value arithmetic processor 19e combines the multi-rotation amount count value from the multi-rotation detection arithmetic processor 19b with the absolute value of the single-rotation absolute value arithmetic processor 19d when the main power is turned on, and an absolute value signal including the multi-rotation amount. Is transmitted to the host controller.

Next, the operation when the rotating shaft 3 is rotated by an external force in the main power OFF state will be described.
In this case, the induced voltage generated in the coil 2b due to the large Barkhausen effect on the magnetic wire 2a of the power generation device 2 at the rotational position where the permanent magnet is located is Vc, and the magnetic field detection sensors 8a and 8b, comparators 9a and 9b, It is applied to the multi-rotation detection arithmetic processor 19b and the multi-rotation amount count value storage device 19c.

  Next, the multi-rotation detection arithmetic processor 19b reads the pulse signals obtained by converting the detection signals of the magnetic field detection sensors 8a and 8b by the comparators 9a and 9b, detects an increase / decrease in the multi-rotation amount count value, and updates the count value. Then, the updated count value is stored in the multi-rotation amount count value storage device 19c from the multi-rotation detection calculation processor 19b.

FIG. 4 is a signal timing diagram of the power generator in the first embodiment of the present invention.
In FIG. 4, the A phase signal is a signal obtained by converting the output signal of the magnetic field detection sensor 8a shown in FIG. 3 into a pulse signal by the comparator 9a, and the B phase signal is the output signal of the magnetic field detection sensor 8b shown in FIG. Is a signal converted into a pulse signal by the comparator 9b. When the shaft 3 rotates in a certain rotation direction, the magnetic field detection sensors 8a and 8b are arranged so that the A-phase signal and the B-phase signal are output as a one-cycle pulse signal for one rotation having a phase difference of about 90 degrees. It is mounted on the substrate 19. Here, the phase difference of the signal is about 90 degrees, but it is sufficient that there is a phase difference between the rise and fall of the A phase and the B phase.

  In this embodiment, in order to reliably count the increase / decrease in the count value of the multi-rotation amount, the B-phase pulse signal whose multi-rotation amount count value is updated during the period in which Vc can be supplied by the power generation voltage of the power generation device 2. The magnetic field detection sensors 8a and 8b are arranged so that the edge is located at a position where the edge changes from low to high (or from high to low) when the A-phase signal is high (or low). As a result, the count value of the multi-rotation amount changes only while the power generation device 2 generates power. Therefore, an edge change that updates the multi-rotation amount does not occur while the power generation device is not generating power, and the multi-rotation amount is reliably increased. The quantity count value can be updated. Here, it is clear that there is no problem even if the A-phase and B-phase signals are interchanged.

FIG. 5 is a side sectional view showing the configuration of the second embodiment of the present invention.
In FIG. 5, reference numerals 201 and 202 denote power generators, and the difference from the first embodiment of the present invention is that two power generators are arranged. The two power generation devices 201 and 202 can be operated not only as a function of the power generation device but also as a function of a magnetic field detection sensor, so that the magnetic field detection sensors 8a and 8b can be deleted.
FIG. 6 is a front view of the configuration of the second embodiment of the present invention viewed from the power generation device 2 side. The power generators 201 and 202 are arranged on the circuit board 19 with an angular interval of 90 °. Permanent magnets are shown with circular dipole magnetization, but the same effect can be obtained with rectangular dipole magnets.

Next, the operation will be described.
FIG. 7 is a block diagram showing the operation of the second embodiment of the present invention.
The power switch 19a switches between the induced voltage generated in the coil 201b of the power generator 201 and the induced voltage generated in the coil 202b of the power generator 202 and the main power. When the main power is ON, the coil 201b and the coil 202b are switched. The induced voltage generated in the circuit is cut off, and the main power is output as Vc. When the main power supply is OFF, the main power supply is cut off, and the induced voltage generated in the coil 201b and the coil 202b is output as it is without being cut off.

  Furthermore, the induced voltage generated in the coil 201b of the power generation apparatus 201 and the induced voltage generated in the coil 202b of the power generation apparatus 202 are used as a magnetic field detection signal. The generated voltage is shaped by the waveform shapers 9c and 9d so as to meet the input signal voltage specifications of the multi-rotation detection arithmetic processor 19b, and become A-phase and B-phase pulse signals, respectively.

  The power switch 19a also detects that the main power has been cut off, and transmits a main power OFF detection signal to the multi-rotation processor 19b before the main power drops below the operating voltage range of the power switch 19a. have. In addition, in order to lengthen the time during which the main power source falls below the voltage range in which the power switch 19a operates, the capacitor can be charged with charge, or the main power source has such a function.

FIG. 8 is a block diagram showing absolute value signal processing in the second embodiment.
The power sources of the waveform shapers 9b and 9c, the multi-rotation detection arithmetic processing unit 19b, and the multi-rotation amount count value storage device 19c necessary for counting the multi-rotation amount are connected to Vc, and other processing units such as one-rotation absolute The value arithmetic processor 19d and the absolute value arithmetic processor 19e are connected to the main power supply voltage Vmain.

  When the main power supply is ON, the magnetic field detection signals from the power generators 201 and 202 pass through the waveform shapers 9c and 9d and are input to the multi-rotation detection arithmetic processing unit 19b as A-phase and B-phase pulse signals, respectively. The detection calculation processor 19b reads the multi-rotation amount count value data from the multi-rotation amount count value storage device 19c, and counts the multi-rotation amount from the waveform shapers 9c and 9d. At this time, the multi-rotation amount count value may be increased or decreased when the absolute value of one rotation reaches the zero position without using the pulse signals from the waveform shapers 9c and 9d.

  When the main power is turned off, the multi-rotation amount count value held by the multi-rotation detection arithmetic processor 19b until then is stored in the multi-rotation amount count value storage device 19c. Since the power switch 19a can be charged with a capacitor by a capacitor, the multi-rotation detection arithmetic processor 19b, the multi-rotation amount until the time when the multi-rotation amount count value is stored in the multi-rotation amount count value storage device 19c. The voltage at which the count value storage device 19c operates can be held.

  The absolute value arithmetic processor 19e combines the multi-rotation amount count value from the multi-rotation detection arithmetic processor 19b with the absolute value of the single-rotation absolute value arithmetic processor 19d when the main power is turned on, and an absolute value signal including the multi-rotation amount. Is transmitted to the host controller.

Next, the operation when the rotating shaft 3 is rotated by an external force in the main power OFF state will be described.
In this case, the induced voltage generated in the coils 201b and 202b due to the large Barkhausen effect of the magnetic wires 201a and 202a of the power generators 201 and 202 at a rotational position where the permanent magnet is located is the waveform shapers 9c, 9d, It is applied to the multi-rotation detection arithmetic processor 19b and the multi-rotation amount count value storage device 19c.

  The multi-rotation detection arithmetic processor 19b reads the pulse signals from the waveform shapers 9c and 9d, detects increase / decrease in the multi-rotation amount count value, updates the count value, and uses the updated count value as the multi-rotation amount count value. It memorize | stores in the memory | storage device 19c.

FIG. 9 is a timing diagram of the A phase, the B phase, and Vc when the main power supply of the power generator in the second embodiment of the present invention is turned off.
Here, the A phase is a pulse waveform from the power generator 201 through the waveform shaper 9c, the B phase is a pulse waveform from the power generator 202 through the waveform shaper 9d, and Vc is from the power generators 201 and 202 to the power switch 19a. The multi-rotation amount count value increases when each signal changes from left to right in the passed voltage waveform.

  When the multi-rotation amount count value is updated when the A phase is low and the B phase is high, the Vc voltage is first generated. At this time, if the A phase is high and the B phase is low, the count value does not change. . Next, when the Vc voltage is generated and the A phase is low and the B phase is high, the multi-rotation amount count value is incremented by one. Here, when the Vc voltage is generated, the states of the A phase and the B phase are always stored in the data storage device 19c.

  In this way, it is possible to determine the increase / decrease of the multi-rotation amount. For example, the states of the A phase and the B phase stored when the main power source is turned off are turned on. If it is low, then the Vc voltage is generated, and if the A phase is low and the B phase is high, the multi-rotation amount count value increases by one. If the same A phase as the stored state is high and the B phase is low, the multi-rotation amount count value is decreased by one when the A phase is low and the B phase is high next.

  That is, when the Vc voltage is generated, if the A-phase and B-phase pulse states are the same as in the previous time, the multi-rotation count number should be decreased until then, or the multi-rotation count count should be decreased until then. So that it will increase. If the state of the A-phase and B-phase pulses is different from the previous state, the increase / decrease state of the multi-rotation amount count number remains the same. By doing so, it is possible to reliably detect an increase / decrease in the multi-rotation amount counter value.

FIG. 10 (a) is a block diagram around the power generation device and the power supply switching unit according to the third embodiment of the present invention.
The feature of the present embodiment is that a protection circuit 19f is provided between the power generator 2 and the power switch 19a.
As shown in FIG. 10B, the power generation device 2 generates a positive voltage and a negative voltage (negative voltage) centered on 0V. The multi-rotation arithmetic processor 19b and the multi-rotation amount count value storage device 19c are often constituted by digital ICs, and the digital ICs generally operate with 0-3.3V and 0-5V power supplies. In order to operate these ICs, a protection circuit prevents a negative voltage from being applied to Vc. Specifically, a negative voltage is prevented from being applied to the power switch 19a by a diode or the like.

  FIG. 11 is a block diagram around a power generation apparatus and a power switch cited in the second embodiment of the present invention in the third embodiment of the present invention. In this case, a negative voltage is not applied to Vc, and the waveform shapers 9c and 9d are protected from being input with a negative voltage signal.

FIG. 12 is a configuration diagram of a power generation device showing a fourth embodiment of the present invention.
In the figure, 210c is a substrate on which a magnetic wire is mounted. Magnetic wires 210a and 211a having a large Barkhausen effect are arranged on this substrate at a certain distance d. The difference between FIG. 12A and FIG. 12B is that the coil 211b is further wound around the coil 210b in FIG. 12B.
The power generators 2 and 201, 202 are obtained by winding a coil around a magnetic wire having a large Barkhausen effect. In this case, a problem may occur in the time for counting and storing the multi-rotation amount and the power source capacity (power) for driving each processor. As a measure for solving this problem, a method of extending the power generation time is the present embodiment.

Next, the operation will be described.
FIG. 13 is a graph of the power generation voltage of the power generation device in this example.
FIG. 13A is a graph of the generated voltage corresponding to the power generator of FIG. 12A, and shows the generated voltage when the permanent magnet rotates at a constant speed. As shown in the figure, the power generation time can be extended by arranging the magnetic wires 210a and 211a at a certain distance d. In addition, as for this space | interval, it is desirable to set it as the space | interval with which a generated voltage overlaps as shown in a figure.
FIG. 13B is a graph of the generated voltage corresponding to the power generator of FIG. 12B, and the coil 211b is further wound around the coil 210b, so that the generated voltage can be increased as shown in the figure. By increasing the voltage, the time until the voltage decreases can be lengthened.

  Thus, in the present invention, a magnetic coil having a large Barkhausen effect and a coil wound around the magnetic coil are used as a power generator, and a backup power supply is supplied to the multi-rotation detector. The reliability of the absolute encoder device is improved.

1 is a side sectional view of an absolute value encoder device showing a first embodiment of the present invention. 1 is a block diagram showing the operation of a power supply switching device according to a first embodiment of the present invention. The block diagram which shows the absolute value signal processing of 1st Example of this invention Signal timing diagram of the power generator in the first embodiment of the present invention Side sectional view showing the configuration of the second embodiment of the present invention. The front view which shows the structure of 2nd Example of this invention. The block diagram which shows operation | movement of 2nd Example of this invention. The block diagram which shows the absolute value signal processing in 2nd Example of this invention Timing diagram of A phase, B phase, and Vc when main power supply of power generation device in second embodiment of the present invention is OFF Block diagram around a power generator and a power switch showing a third embodiment of the present invention Third embodiment of the present invention Block diagram around a power generator and a power switch cited in the second embodiment of the present invention The block diagram of the electric power generating apparatus which shows 4th Example of this invention The graph which shows the electric power generation voltage in 4th Example of this invention. Partial front view of the absolute value encoder in the first prior art Side surface sectional drawing containing the main body of the absolute value encoder in the AA of FIG. Block diagram of electronic circuit section in first prior art The figure which showed the detection part structure and output signal waveform of the encoder in 2nd prior art The perspective view which shows the detection part structure of the encoder in 3rd prior art. Operation explanatory diagram of the encoder in the third prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Absolute value encoder apparatus 2, 201, 202 Electric power generation apparatus 2a, 201a, 202a, 210a, 211a Magnetic wire 2b, 201b, 202b 210b, 211b Coil 3 Shaft 4 Encoder stator 5 Rotating disk 6 Bearing 7 Permanent magnet 8a, 8b Magnetic field detection Sensors 9a, 9b Comparators 9c, 9d Waveform shaper 19 Circuit board 19a Power switch 19b Multi-rotation detection arithmetic processor 19c Multi-rotation amount count value storage device 19d Single-rotation absolute value arithmetic processor 19e Absolute value arithmetic processor 19f Protection circuit

Claims (5)

In an absolute value encoder including an absolute position detector that detects an absolute position within one rotation of a rotation shaft and a multi-rotation detector that detects multiple rotations,
The multi-rotation detector includes a permanent magnet provided at a tip of the rotation shaft;
A power generation device that is configured of a magnetic wire and a coil having a large Barkhausen effect and is provided at a position where the magnetic field of the permanent magnet can be detected;
With
An absolute value encoder device, wherein a power source of the multi-rotation detector is backed up by a voltage generated from the power generator when an external power source is shut off. The multi-rotation detector includes a magnetic field detection sensor that outputs two pulse signals having a phase difference,
2. The absolute value encoder device according to claim 1, wherein the magnetic field detection sensor is arranged so that one of the two pulse signals changes to high or low during power generation of the power generation device. In an absolute value encoder including an absolute position detector that detects an absolute position within one rotation of a rotation shaft and a multi-rotation detector that detects multiple rotations,
The multi-rotation detector includes a permanent magnet provided at a tip of the rotation shaft;
Two power generators composed of magnetic wires and coils having a large Barkhausen effect, which detect the magnetic field of the permanent magnet and are provided at positions where the generated voltages have a phase difference;
With
The power of the multi-rotation detector is backed up by the voltage generated from the power generation device when the external power supply is shut off, and the multi-rotation amount is detected by counting the voltages from the two power generation devices. Absolute value encoder device.   4. The absolute value encoder device according to claim 1, further comprising a protection circuit that prevents an overvoltage and a reverse voltage generated by the power generation device between the power generation device and the power supply switching device.   The absolute value encoder according to claim 1 or 3, wherein the power generation device includes a plurality of magnetic wires having a large Barkhausen effect arranged at a certain interval, and a coil for generating an induced voltage is arranged around the magnetic wires. apparatus.

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