JP7393577B1 - Rotary encoder and servo control device using it - Google Patents

Abstract

The present invention provides a rotary encoder that has a function of generating highly accurate signals regarding the angular position and rotational speed of a rotating shaft, is equipped with a backup power source, and has a compact configuration. [Solution] Equipped with a magnet fixed to a rotating shaft and a function to generate information regarding the rotation angle and rotation direction of the rotating shaft from the output of a magnetic sensor placed opposite the magnet, and the magnet has a boundary line passing through its center. It has a disc shape with a set of N and S pole regions formed in the radial direction as a boundary, and a set of N and S pole regions forms one flat surface, resulting in large Barkhausen effect power generation. The unit includes a ferromagnetic wire, a power generation coil, and first and second magnetic plates connected to both ends of the ferromagnetic wire. The first and second magnetic plates extend to the outside of the magnet, and the first and second magnetic plates extend apart from each other along both side surfaces of the magnet, and the first and second magnetic plates have a line-symmetrical shape with the magnet in between in the axial direction of the rotating shaft. [Selection diagram] Figure 2

Description

The present invention relates to a rotary encoder and a servo control device using the same, and more particularly to a rotary encoder equipped with a large Barkhausen effect power generation unit and a servo control device using the same.

A rotary encoder is used to generate information regarding the angular position and rotation speed of a rotating shaft driven by a rotating electrical device. Based on the angular position and rotational speed of the rotating shaft detected by the rotary encoder, highly accurate absolute digital signals and incremental digital signals regarding the angular position are generated and output, and these signals can be used, for example, to servo control a motor equipped with an encoder. It is used to control equipment as a servo motor.
Rotary encoders used in servo control devices that control equipment such as industrial robots where system redundancy is important include those that have two independent rotary encoder functions, such as those called safety encoders. be.
The rotary encoder is equipped with a backup power source so that position data information will not be lost even if the main power supply is cut off. This backup power source uses a power generation device that utilizes the large Barkhausen effect, and is used to detect multiple rotation information of the absolute encoder.

Patent Document 1 discloses a rotation detection device that uses a composite magnetic wire and a pickup coil and uses self-power generation. This device includes one detection magnet attached to a rotating shaft, and a detection section that is arranged opposite to this detection magnet and detects rotation of the rotating shaft. The detection unit includes a composite magnetic wire having a large Barkhausen effect, which is centered on an extension of the rotation axis and is provided in the circuit board so as to be orthogonal to the rotation axis, and a pickup coil surrounding the composite magnetic wire. It is configured.

Patent Document 2 discloses an encoder that includes an optical or magnetic angle detection section that employs a composite magnetic wire having a large Barkhausen effect in an electric signal generation section. This encoder includes a position detection part that detects the position of the moving part, a magnet that has a plurality of polarities along the moving direction of the moving part, and a sensor whose magnetic characteristics change due to changes in the magnetic field as the moving part moves. a magnetic part, a first magnetic body for guiding the magnetic flux lines of the magnet to the magnetically sensitive part, an electric signal generating part that generates an electric signal based on the magnetic properties of the magnetically sensitive part, and the magnet and the magnetically sensitive part. and a second magnetic body disposed between the magnetic part and the second magnetic body for guiding magnetic flux lines of a portion of one polarity of the magnet to a portion of the other polarity of the magnet.

WO2016/170648A1 WO2019/188859A1

The rotation detection device described in Patent Document 1 includes a power generation device that utilizes the large Barkhausen effect, and detects a rotation direction and rotation speed by detecting a pulse signal of a composite magnetic wire. However, there is no disclosure of generating and outputting highly accurate absolute digital signals or incremental digital signals.

The encoder power generation device described in Patent Document 2 has the function of generating high-precision absolute digital signals and incremental digital signals and securing sufficient power. A plurality of arranged permanent magnets are used, and each permanent magnet has a north pole and a south pole stacked on top of each other in the axial direction. Therefore, the device is complicated and large.

One of the things to consider when trying to increase the precision and make a rotary encoder equipped with a magnetic encoder more compact is to prevent the output of a magnetic sensor from receiving magnetic field interference.
Additionally, depending on the application of the rotary encoder, two-system rotary encoders are known that are equipped with a high-precision optical encoder and a power generation device, and are also equipped with a magnetic encoder that generates signals related to angular position and rotation speed. There is. In such a rotary encoder, the magnetic encoder may be required to have high accuracy comparable to that of an optical encoder, or may be used auxiliary and therefore not required to have high accuracy.

One object of the present invention is to provide a rotary encoder that has a function of generating highly accurate signals regarding the angular position and rotational speed of a rotating shaft, has a backup power source, and has a compact configuration, and a servo control using the rotary encoder. The goal is to provide equipment.
Another object of the present invention is to provide a rotary encoder that has a function of generating highly accurate signals regarding the angular position and rotational speed of a rotating shaft, has a backup power source, and takes into account magnetic field interference of a magnetic encoder, and the rotary encoder. An object of the present invention is to provide a servo control device using a servo control device.
Still another object of the present invention is to provide a rotary encoder that has the functions of two independent systems of rotary encoders including a magnetic encoder, is inexpensive, and has a compact configuration, and a servo control device using the rotary encoder. There is a particular thing.

According to one aspect of the present invention, the present invention has a function of generating information regarding the rotation angle and rotation direction of the rotation shaft from the output of a magnet fixed to the rotation shaft and a magnetic sensor arranged opposite to the magnet. A rotary encoder, the rotary encoder comprising a large Barkhausen effect power generation unit as a power supply unit,
The magnet fixed to the rotating shaft is a disc-shaped magnet in which a set of N-pole region and S-pole region are formed in the radial direction with a boundary line passing through the center of the magnet. the north pole region and the south pole region form one flat surface;
The large Barkhausen effect power generation unit includes a ferromagnetic wire, a power generation coil, and a first magnetic plate and a second magnetic plate connected to both ends of the ferromagnetic wire,
The first magnetic plate and the second magnetic plate extend from both ends of the ferromagnetic wire to the outside of both side surfaces of the magnet with the magnet in between,
The first magnetic plate and the second magnetic plate extend apart from each other along both side surfaces of the magnet,
The first magnetic plate and the second magnetic plate are characterized in that they have a line-symmetrical shape with the magnet sandwiched therebetween in the axial direction of the rotating shaft.
According to the present invention, there is provided a rotary encoder in which a magnetic sensor has a function of generating highly accurate signals regarding the angular position and rotational speed of a rotating shaft, is further equipped with a backup power source, and has a compact configuration, and a rotary encoder using the same. It is possible to provide a servo control device according to the present invention.

According to another aspect of the present invention, the first magnetic plate and the second magnetic plate mainly accept magnetic flux lines in an outer direction parallel to or close to the surface of the magnet, and the magnetic flux lines are directed toward the magnetic sensor. It is configured to suppress the influence of magnetic field interference.
Thereby, the accuracy of the magnetic sensor can be ensured while one magnet is used both as a magnet for the magnetic sensor and as a magnet for the large Barkhausen effect power generation unit. Therefore, we are developing a rotary encoder that has the function of generating highly accurate signals regarding the angular position and rotational speed of the rotating shaft, has a backup power source, and takes into account the magnetic field interference of the magnetic encoder, and a servo control device using the rotary encoder. can be provided.

According to another aspect of the present invention, each other end of the first magnetic plate and the second magnetic plate on the opposite side from the ferromagnetic wire is an open end with the magnet sandwiched therebetween, Each of the open ends is characterized in that it projects in a tapered shape.
As a result, a single disk-shaped magnet can be used both as a magnet for a magnetic sensor and as a magnet for a large Barkhausen effect power generation unit, while creating a power generation device that utilizes the large Barkhausen effect as a backup power source with a compact configuration. It is possible to achieve high output at the same time.

As an aspect of the present invention, it is more preferable that the rotary encoder is configured as a safety encoder. For example, the magnetic sensor includes a first TMR sensor and a second TMR sensor, the first TMR sensor is installed on a printed circuit board held in an encoder housing at a position facing the magnet, and the second TMR sensor is installed at a position facing the magnet. It is installed on the back side of the first TMR sensor on the substrate.
Thereby, it is possible to provide a safety encoder that has the functions of two independent systems of rotary encoders and has a compact configuration.
When used as a safety encoder, in addition to the combination of a pair of TMR sensors, various sensor combinations such as a combination of a TMR sensor and a GMR sensor, a pair of GMR sensors, or a combination of a TMR sensor and an optical sensor are possible. , it is possible to provide an appropriate safety encoder according to the application.

According to another aspect of the present invention, the first magnetic plate and the second magnetic plate extend from both ends of the ferromagnetic wire onto the surface of the magnet to near both side surfaces of the magnet, and The first magnetic plate and the second magnetic plate extend apart from each other on the surface of the magnet, and the first magnetic plate and the second magnetic plate are linearly symmetrical on the surface of the magnet. It has the shape of
As a result, one magnet can be used both as a magnet for a magnetic sensor and as a magnet for a large Barkhausen effect power generation unit, while also having the functions of two independent rotary encoders including a magnetic encoder, and is inexpensive. , it is possible to provide a rotary encoder with a compact configuration and a servo control device using the same.

1 is a functional block diagram showing a configuration example of a rotary encoder according to a first embodiment of the present invention. FIG. FIG. 3 is a longitudinal cross-sectional view showing an example of the configuration of a magnetic sensor and a power supply unit in the first embodiment. FIG. 2 is a plan view of an encoder housing showing a configuration example of a large Barkhausen effect power generation unit in a first embodiment. 3 is a diagram showing the positional relationship among the magnet, magnetic sensor, and power supply unit shown in FIG. 2, and the relationship between magnetic flux lines. FIG. FIG. 6 is a diagram showing the rotation of the magnet and the positional relationship between the first magnetic plate and the second magnetic plate of the large Barkhausen effect power generation unit in the first embodiment. FIG. 3 is a diagram conceptually explaining the function of the large Barkhausen effect power generation unit in the first embodiment. FIG. 3 is a diagram showing an example of the relationship between a magnet, a first magnetic plate, and a second magnetic plate in the first embodiment. It is a figure which shows the other example of the relationship between a magnet, a 1st magnetic board, and a 2nd magnetic board. It is a figure which shows the other example of the relationship between a magnet, a 1st magnetic board, and a 2nd magnetic board. It is a figure which shows the other example of the relationship between a magnet, a 1st magnetic board, and a 2nd magnetic board. It is a figure which shows the other example of the relationship between a magnet, a 1st magnetic board, and a 2nd magnetic board. It is a figure which shows an example of the characteristic of a 1st magnetic board and a 2nd magnetic board in 1st Example. FIG. 3 is a diagram illustrating one configuration example of a circuit of a power supply unit in the first embodiment. FIG. 7 is a diagram showing another example of the configuration of the circuit of the power supply unit in the first embodiment. It is a time chart showing the operation of the power supply unit, and is a diagram showing an example of the relationship between the power supply and the output signal of the rotary encoder when the main power supply is in a normal state and then loses power. FIG. 3 is a diagram showing the relationship between the rotation of a magnet and the output of a magnetic sensor (TMR sensor) in the first example. FIG. 3 is a diagram illustrating the process of digitizing and absoluteizing the first and second TMR sensor signals. 5 is a flowchart showing signal processing in the first TMR sensor signal processing unit in the first embodiment. 13 is a diagram showing examples of A-phase and B-phase signals and incremental Z-phase, U-phase, V-phase, and W-phase signals generated based on these signals based on the signal processing of FIG. 12. FIG. FIG. 7 is a plan view of an encoder housing showing a configuration example of a large Barkhausen effect power generation unit in a second embodiment of the present invention. FIG. 3 is a functional block diagram showing a configuration example of a rotary encoder according to a third embodiment of the present invention. FIG. 7 is a longitudinal cross-sectional view showing a configuration example of a TMR sensor, an optical sensor, and a power supply unit in a third embodiment. FIG. 7 is a longitudinal cross-sectional view showing a configuration example of a magnetic sensor and a power supply unit in a fourth embodiment. FIG. 7 is a plan view of an encoder housing showing a configuration example of a large Barkhausen effect power generation unit in a fourth embodiment.

The rotary encoder of the present invention includes, as a means for generating information regarding the angular position and rotation speed of the rotating shaft, one disc-shaped magnet fixed to the rotating shaft, and at least one disc-shaped magnet arranged opposite to the magnet. Equipped with two magnetic sensors. That is, the rotary encoder of the present invention includes at least one magnetic sensor and can be applied to various rotating electric machines that require absolute data, incremental A, B, Z data, and the like. Each embodiment of the present invention will be described below.

First, a rotary encoder according to a first embodiment of the present invention will be described. First, the overall configuration and functions of a rotary encoder according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.
FIG. 1 is a functional block diagram showing an example of the configuration of a rotary encoder, and FIG. 2 is a diagram showing an example of the configuration of a TMR sensor and a power supply unit.
The rotary encoder 10 includes a TMR sensor unit 11, a power supply unit 12, a temperature sensor 13, a system control unit 14, and two sets of magnetic sensor signal processing units (a first TMR sensor signal processing unit 15, a second TMR sensor signal processing unit 16). ). That is, the rotary encoder 10 has the functions of two independent systems of rotary encoders.
The rotary encoder 10 further includes one flat disk-shaped magnet 110 that is magnetized with one N polarity and one S polarity, that is, has only one set of polarities N and S. This one disk-shaped magnet has a set of N-pole region and S-pole region formed in the radial direction with a boundary line 1101 (see FIG. 3) passing through its center, and has a flat front surface and a back surface. , and a side surface. This magnet 110 is, for example, a neodymium magnet, and as shown in FIG. 2, is fixed to one end surface of the rotating shaft 510 with a non-magnetic holding member 1102, an adhesive, or the like. Note that a samarium cobalt magnet or a ferrite magnet may be used instead of the neodymium magnet. The rotating shaft 510 is driven directly or indirectly via a speed change mechanism or the like by a rotating electric machine such as a motor driven by a servo control device to which the output of a rotary encoder, a driving command, etc. are input.

The TMR sensor unit 11 includes a first TMR sensor 111 and a second TMR sensor 112 arranged on a printed circuit board 19, and a temperature sensor 113. The first TMR sensor 111 and the second TMR sensor 112 are two sets of TMR sensors that have the same specifications and therefore the same output characteristics.
The printed circuit board 19 is fixed to the upper end of a cylindrical encoder housing 40. The encoder housing 40 is made of, for example, non-magnetic aluminum or other material, and is fixed to a rotating device to which the encoder is attached, such as an end cover of a motor. Alternatively, something equivalent to the encoder housing 40 may be formed integrally with a member constituting an end cover, a storage container, etc. of the rotating device. In the present invention, for convenience, such a housing is also defined as an encoder housing. A rotating shaft 510 of a rotary device is located in the hollow portion 41 of this encoder housing 40, and a magnet 110 is fixed to the end of this rotating shaft. The encoder housing 40 is covered with a cover 46 made of a magnetic material, and the end cover side of the motor is also covered with a magnetic material, so that the inside of the encoder housing 40 is magnetically shielded.
The first TMR sensor 111 is disposed on the lower side of the printed circuit board 19, that is, on the lower surface facing one magnet 110, at a position corresponding to the axis O _S - O _S of the rotating shaft 510, and The sensor 112 is arranged on the upper surface of the printed circuit board 19 at a position corresponding to the axis O _S -O _S . The first and second TMR sensors 111 and 112 output analog signals of sine waves and cosine waves as the magnet 110 rotates.

The power supply unit 12 includes a main power supply 121 , a large Barkhausen effect power generation power supply 122 charged by a large Barkhausen effect power generation unit 115 , and a backup power supply 123 , which together with the main power supply 121 supply power to the rotary encoder 10 . It functions as a power supply that supplies
The main body of the large Barkhausen effect power generation unit 115 is installed in a housing section 42 in which a part of the encoder housing 40 is recessed. This large Barkhausen effect power generation unit 115 includes a ferromagnetic wire (or composite magnetic wire) 1152 such as a Wiegand wire, a power generation coil 1154 provided around the ferromagnetic wire 1152, and a power generation coil 1154 connected to both ends of the ferromagnetic wire 1152. The first magnetic plate 1156 and the second magnetic plate 1158 are provided.
These magnetic plates 1156 and 1158 are made of the same magnetic material, and are arranged at the same position (height) as the magnet 110 in the direction of the axis O _S - O _S of the rotating shaft 510. These magnetic plates extend to the outside of both sides of the magnet and are spaced apart along both sides of the magnet. That is, the midpoint of the thickness (axial length) of the first magnetic plate 1156 and the second magnetic board 1158 is the midpoint of the thickness (axial length) of the magnet 110 and the center of the ferromagnetic wire 1152. It lies on the connecting straight line O _mgR - O _mgR . However, this is an ideal case. Practically, the first magnetic plate and the second magnetic plate are at the same height, that is, they mainly accept lines of magnetic flux in an outer direction parallel to or close to the surface of the magnet, and the magnetic sensor It is sufficient if the configuration is such that the influence of magnetic field interference on the magnetic field is suppressed. Therefore, the midpoint between the thicknesses of these magnetic plates may be within or near the front and back surfaces of the magnet. In the present invention, including such a range, the first magnetic plate and the second magnetic plate are defined as being at the same position (height) as the magnet.

The first magnetic plate 1156 and the second magnetic plate 1158 are arranged so that the magnetic flux lines from the N-pole region and the magnetic flux lines from the S-pole region are connected to the first magnetic plate 1156 and the second magnetic plate by the rotating magnetic field accompanying the rotation of the magnet 110. A predetermined gap Ga is provided between both sides of the magnet 110 so that it can be properly guided to the plate 1158. That is, these magnetic plates extend along the tangents 110a, 110b of both side surfaces of the disc-shaped magnet parallel to the axis of symmetry, spaced apart from the tangents by a gap Ga. When the gap Ga is narrow, these magnetic plates tend to cause magnetic field interference that affects the output of the TMR sensor unit 11. On the other hand, if the gap is too wide, these magnetic plates will not be able to obtain sufficient lines of magnetic flux from both the north and south pole regions. Taking these things into consideration, the gap Ga may be set appropriately. Furthermore, the ends of these magnetic plates on the magnet side are open ends with the magnet 110 in between.

FIG. 3 is a diagram showing a configuration example of the large Barkhausen effect power generation unit 115. When the rotating shaft 510 is at a position corresponding to the origin position of the motor, a boundary line 1101 between the N-pole region and the S-pole region of the magnet passes through the center of the flat surface of the magnet. That is, the boundary line 1101 is on a straight line O _mgV - O _mgV passing through the axis O _S - O _S (see FIG. 2) of the rotating shaft 510. The first magnetic plate 1156 and the second magnetic plate 1158 shown here are strip-shaped corner members, and on the side surface of the magnet 110, their center lines O _G1 and O _G2 are straight lines O _mgR - O _mgR (axis of symmetry) and extends parallel to both sides of it. That is, the axis of symmetry O _mgR - O _mgR of these magnetic plates is perpendicular to the straight line O _mgV - O _mgV and passes through the center of the disc-shaped magnet 110. Considering manufacturing tolerances, in practice, the axis of symmetry only needs to pass through the center of the disc-shaped magnet 110 or its vicinity (hereinafter referred to as "near the center of the magnet"). In addition, since the first magnetic plate 1156 and the second magnetic plate 1158 have a thickness in the direction of the axis O _S - O _S , the plane of each position of this thickness has line symmetry with respect to the axis of symmetry. Needless to say, it has the shape of
In this way, the first magnetic plate 1156 and the second magnetic plate 1158 have a line-symmetrical shape with the magnet in between, at least near the side surface of the magnet 110. That is, as shown in FIG. 3, the first magnetic plate 1156 and the second magnetic plate 1158 have a line-symmetric shape with respect to the axis of symmetry. Therefore, the first magnetic plate 1156 and the second magnetic plate 1158 face the side surface of one magnet 110 with the same magnetic properties.

Note that the cross-sectional shape of the first magnetic plate 1156 and the second magnetic plate 1158 can be any plate-like or rod-like shape, such as a rectangle, circle, ellipse, or trapezoid, as long as the condition of line symmetry is satisfied. Further, as long as the condition of line symmetry is satisfied, there may be non-parallel portions. Furthermore, the shapes of the first magnetic plate 1156 and the second magnetic plate 1158 may be slightly different in a section away from the magnet 110 and close to the large Barkhausen effect power generation unit 115 if there are structural restrictions. It's okay. However, it is desirable that the magnetic properties for guiding lines of magnetic flux be the same.
Further, it is preferable that the open ends of the first magnetic plate 1156 and the second magnetic plate 1158, that is, the tips 1156a and 1158a, protrude in a tapered shape, for example, a square pyramid shape or a conical shape. This makes it easier to collect magnetic flux lines. Note that the protruding direction of the tip of each open end may be directed toward the direction of the magnet 110, that is, toward the center of the magnet 110, or in a direction perpendicular to the axis of symmetry. As a result, a single disk-shaped magnet can be used both as a magnet for a magnetic sensor and as a magnet for a large Barkhausen effect power generation unit, while creating a power generation device that utilizes the large Barkhausen effect as a backup power source with a compact configuration. It is possible to achieve high output at the same time.

FIG. 4 shows the positional relationship among the magnet, the TMR sensor, and the power supply unit, and the relationship between the lines of magnetic flux. Due to the rotating magnetic field, the magnetic flux line φ1 passes through the first TMR sensor 111, the magnetic flux line φ2 passes through the second TMR sensor 112, and the magnetic flux line φ3 passes through the first and second magnetic plates 1156 and 1158. Therefore, the magnetic flux line φ1 and the magnetic flux line φ2 directed from the N pole to the S pole of the magnet maintain the first and second TMR sensors 111 and 112 in an appropriately operable state, and the output of the large Barkhausen effect power generation unit. It is necessary to configure the first magnetic plate 1156 and the second magnetic plate 1158 so that the influencing magnetic flux line φ3 is optimized. That is, φ1 to φ3 are determined by the size of the magnet 110 (diameter of the rotating shaft), the strength H of the magnetic field supplied by the magnet, the magnetic flux density B, the characteristics of the TMR sensor, and the output required for the large Barkhausen effect power generation unit. It may be set as appropriate depending on the situation. It is also necessary to consider the magnetic permeability of the material forming these magnetic plates.

In the present invention, the magnetic flux line φ1 directed toward the first TMR sensor is mainly directed upward in the axial direction (direction perpendicular to the surface of the magnet) from inside the N-pole region near the boundary line 1101 of the magnet, and then further inside the S-pole region. The magnetic flux line φ2 directed toward the second TMR sensor is mainly a magnetic flux line axially upward from the outside of the N-pole region away from the boundary line 1101 and further toward the outside of the S-pole region. configured.
On the other hand, the magnetic flux line φ3 used in the large Barkhausen effect power generation unit mainly extends from the outside or side of the N-pole region of the magnet, in a horizontal direction to the surface of the magnet, or in a direction close to the outer circumference, and furthermore, It utilizes lines of magnetic flux that return outwardly through the plate to the outside or side of the S-pole region. In this way, in order to suppress the influence of magnetic field interference on the magnetic flux line φ1 toward the first TMR sensor and the magnetic flux line φ2 toward the second TMR sensor, the first magnetic plate and the second magnetic plate mainly The magnetic flux line φ3 is configured to receive a magnetic flux line φ3 in a horizontal direction or an outer direction close to the horizontal direction with respect to the surface.
As an example, the diameter of the rotating shaft 510 is approximately 6.0 to 8.0 mm, the thickness of the printed circuit board is approximately 1.0 to 1.2 mm, the diameter of the magnet is approximately 5.0 to 10.0 mm, and the thickness of the magnet is 3 mm. In the case of approximately 0.5 to 3.0 mm, the gap _G1 is preferably approximately 0.5 to 3.0 mm. Further, the gap Ga is also preferably about 0.5 to 3.0 mm.

Returning to FIG. 1, the system control unit 14 includes an initial setting section 141, an encoder input/output control unit 144, a safety control unit 145, a serial/parallel signal transmission/reception unit 147, and the like. The initial setting unit 141 has a function of setting the type of motor, the number of poles, the origin position, the output conditions of the rotary encoder, etc. according to the conditions input via the user interface 142. The encoder input/output control unit 144 has a function of controlling the input/output of the rotary encoder 10 according to initially set conditions.

The encoder of this embodiment has the functions of two independent systems of rotary encoders, and the safety control unit 145 includes the first TMR sensor 111, the second TMR sensor 112, the first TMR sensor signal processing unit 15, and the second TMR sensor signal The output state of the processing unit 16 is monitored, and if either of the functions of the two rotary encoders fails, necessary processing is performed to safely stop the operation of the rotary encoder. This allows the rotary encoder to function as a safety encoder. The serial/parallel signal transmitting/receiving unit 147 has a function of converting various types of information into parallel signals or serial signals and transmitting and receiving the information between the rotary encoder 10 and the servo control device.

The first TMR sensor signal processing unit 15 includes an analog signal processing section 151 that processes a first analog signal, an AD converter 152, and a digital signal processing section 153, and is arranged opposite to the magnet 110. The first analog signal that is the output of the first TMR sensor is subjected to AD conversion, and based on this AD conversion data, first digital data regarding the rotation angle and rotation direction of the rotation shaft is generated. That is, the first TMR sensor signal processing unit 15 converts the analog output of the first TMR sensor 111 into a high-resolution (for example, 27 bits/rotation) absolute signal, which is quantized under predetermined conditions, regarding the rotation angle information of the rotation axis. It has a function of generating two systems of incremental signal information as first digital data with high precision.

The analog signal processing unit 151 receives the sampling data of the first analog signal (Sin signal, Cos signal) of the first TMR sensor 111 as time series data, and processes it with the rotation speed Nx of the rotating shaft and data of the temperature sensors 13 and 113. Correlate and record in memory. That is, the sampling data of the analog signal of the first TMR sensor 111 is input to the 64-bit AD converter 152 (ADC-1 (Sin) 1521, ADC-2 (Cos) 1522) and converted into digital values. The converted values are recorded in EEPROM-1 (1523) as time series data.

The incremental A, B, Z, (U, V, W) signal generation unit 1531 of the first TMR sensor of the digital signal processing unit 153 generates an absolute signal of the rotation angle of the rotation axis, which is the first digital data, from the EEPROM-1. The digital values of are acquired, and incremental A, B, Z, (U, V, W) signals are generated and recorded in the EEPROM-2 as time series data. The one-rotation absolute signal generation unit 1532 of the first TMR sensor acquires AD conversion data of the rotation axis from the EEPROM-1, generates a one-rotation absolute signal, and records it in the EEPROM-2. Further, the multi-rotation absolute signal generation unit 1533 of the first TMR sensor generates a multi-rotation absolute signal and records it in the EEPROM-2.

Further, the second TMR sensor signal processing unit 16 includes an analog signal processing section 161, an AD converter 162, and a digital signal processing section 163.
In the second TMR sensor signal processing unit 16, the analog signal sampling data is input to a 64-bit AD converter 162 (ADC-1 (Sin) 1621, ADC-2 (Cos) 1622) and converted into a digital value. , and their converted values are recorded in EEPROM-3 (1623) as time series data.

The incremental A, B, Z, (U, V, W) signal generation unit 1631 of the second TMR sensor of the digital signal processing section 163 acquires the digital value from the EEPROM-3, calculates its frequency, and rotates it. It is recorded in EEPROM-4 along with the direction data. The absolute signal generation unit 1632 of the second TMR sensor acquires AD conversion data of the rotation axis from the EEPROM-3, generates a one-rotation absolute signal, and records it in the EEPROM-4 as time-series data. Further, the multi-rotation absolute signal generation unit 1633 of the second TMR sensor generates a multi-rotation absolute signal and records it in the EEPROM-4.
That is, the second TMR sensor signal processing unit 16 performs AD conversion on the second analog signal that is the output of the second TMR sensor, and performs high resolution (for example, 27 bits/rotation) under the same conditions as the first TMR sensor signal processing unit 15. ) are generated as second digital data.

From the rotary encoder 10, based on the output of the encoder input/output control unit 144, either the first digital data or the second digital data is sent as transmission data (BUS) for serial transmission, for example, as an absolute signal and an incremental signal. from the serial/parallel signal transmitting/receiving unit 147 to a device external to the rotary encoder 10, such as a servo control device, via a communication cable.

Note that each functional block shown in FIG. 1 is shown as an example. It goes without saying that the division of each functional block is arbitrary, and the plurality of functional blocks described above may be realized by a common program, or a specific functional block may be realized by a plurality of different programs or IC circuits. stomach.
Alternatively, each of the above functions can be realized by installing a program for executing each of the above functions in a microcomputer equipped with a CPU and a memory.

As shown in FIG. 2, most of the rotary encoder 10, that is, the portion of the TMR sensor unit 11 excluding the disc-shaped magnet 110, the power supply unit 12, the temperature sensor 13, the system control unit 14, and the first TMR sensor signal. The processing unit 15 and the second TMR sensor signal processing unit 16 are formed or mounted on the printed circuit board 19.
In particular, the system control unit 14, the first TMR sensor signal processing unit 15, and the second TMR sensor signal processing unit 16 are implemented as a dedicated FPGA 18 (Field Programmable Gate Array), as an ASIC (Application Specific Integrated Circuit), or as an ASIC (Application Specific Integrated Circuit). It is realized as an IC circuit chip using a general-purpose single-chip microcomputer, and is mounted on a printed circuit board 19. Further, the AD converter 152 and the AD converter 162 are also mounted on the printed circuit board 19 as an ASIC (or FPGA). Further, a capacitor constituting the backup power supply 123 is also mounted on the printed circuit board 19.

Note that the system control unit 14, the first TMR sensor signal processing unit 15, and the second TMR sensor signal processing unit 16 are functionally divided blocks, and these functions are implemented by the digital signal processing of FPGA or ASIC. This is realized by writing programs in units, SSC interfaces, incremental interfaces, etc.
Further, the FPGA includes a ROMRAM and at least one rewritable (overwritable) nonvolatile memory, and is connected to the CPU via a bus. Furthermore, EEPROM, FRAM (registered trademark), (Ferroelectric Random Access Memory), or the like may be used as a rewritable (overwriting) nonvolatile memory. In the following description, such a memory will simply be referred to as an EEPROM.

Note that the position of one end of the magnet 110 on the boundary line 1101 between the N-pole region and the S-pole region corresponds to a specific position in the circumferential direction on the rotating shaft, that is, the rising time of the A-phase pulse. This is the origin position (Z ₀ ).

Next, referring to FIGS. 5 and 6, the rotating magnetic field of the magnet, that is, the rotation angle of the rotating shaft, the first magnetic plate, and the second magnetic plate of the large Barkhausen effect power generation unit in the first embodiment will be explained. We will explain the relationship between
FIG. 5 is a diagram showing the rotation of the north and south pole regions of the magnetic field as the magnet rotates, and the positional relationship between the first magnetic plate and the second magnetic plate of the large Barkhausen effect power generation unit. . That is, when the magnet 110 is in each of the rotational positions (A) to (I), the magnet 110, the first magnetic plate 1156, and the second magnetic plate 1158 face the N-pole region and the S-pole region, respectively. The area where the image is displayed is indicated by diagonal lines within one rectangle. The size of the area of these opposing regions is related to the density of the magnetic flux lines φ3 that travel from the N-pole region of the magnet 110 to the S-pole region via the first and second magnetic plates 1156 and 1158. That is, it is related to the direction of the magnetic flux line φ3 in the first and second magnetic plates 1156 and 1158.
FIG. 5A shows a state in which the magnet 110 is at the origin position (Z ₀ ), that is, at a rotation angle of 0 degrees. In this state, the first magnetic plate 1156 and the second magnetic plate 1158 face the N-pole region and the S-pole region of the magnet 110 under the same conditions. That is, the first magnetic plate 1156 and the second magnetic plate 1158 receive magnetic flux lines φ from the N-pole region and the S-pole region under the same conditions.
In FIG. 5B, where the magnet 110 has been rotated by 45 degrees from this state, the first magnetic plate 1156 has a wide area facing the north pole region, and the second magnetic plate 1158 has a wide area facing the south pole region. ing. Furthermore, in FIG. 5C, where the magnet 110 has been rotated by 90 degrees, the first magnetic plate 1156 faces only the north pole region, and the second magnetic plate 1158 faces only the south pole region. In this way, as the magnetic plate 1156 rotates from 0 degrees to 90 degrees, the first magnetic plate 1156 faces the north pole region, and the second magnetic plate 1158 faces the south pole region over a larger area. Furthermore, in FIG. 5D, which has been rotated by 135 degrees, the area of the first magnetic plate 1156 facing the N-pole region is decreased, and the area of the second magnetic plate 1158 facing the S-pole region is decreased.
In this way, as the magnet 110 rotates, the opposing areas of the first magnetic plate 1156 and the second magnetic plate 1158 and the N-pole region and the S-pole region change. Similarly, as the magnet 110 rotates over 180 degrees as shown in FIGS. 5(E), (F), and (G), the first magnetic plate 1156 and the second magnetic plate 1158 The area of the region facing the N-pole region and the S-pole region increases and decreases periodically. This means that as the magnet 110 rotates, the density and direction of the magnetic flux lines φ3 in these magnetic plates change.
Note that, in reality, it goes without saying that the direction of the magnetic flux line φ3 and the density are not determined only by the size relationship of the rectangular areas shown in FIG. For example, the first and second magnetic plates also extend to the right side of the rectangle, and that part also has a magnetism collecting effect. Further, when the open ends of the first and second magnetic plates are tapered, it is necessary to take into consideration the magnetism collecting effect. However, from FIG. 5, it is possible to know the general tendency of the change in the density of the magnetic flux line φ3 as the magnet rotates.

FIG. 6 is a diagram conceptually explaining the functions of the large Barkhausen effect power generation unit.
One end of each of the first magnetic plate 156 and the second magnetic plate 1158 is connected to the ferromagnetic wire 1152 of the large Barkhausen effect power generation unit 115, and each other end on the opposite side is an open end with the magnet 110 in between. It becomes.
As is clear from FIG. 5, as the magnet 110 rotates from 0 degrees to 90 degrees, as shown in (A), (B), and (C) of FIG. That is, the density of the magnetic flux lines φ3 that exit from the north pole region of the magnet, pass through the first magnetic plate 1156 and the second magnetic plate 1158, and return to the south pole region increases. That is, up to 90 degrees, the magnetic flux supplied to the power generation coil 1154 of the large Barkhausen effect power generation unit 115 increases, and after that, when it exceeds 90 degrees, it flows from the N pole region of the magnet through the first magnetic plate 1156. When the density of the magnetic flux line φ3 in the direction toward the second magnetic plate 1158 and the S-pole region decreases, and the magnet further rotates, the magnetic flux line φ3 decreases in the opposite direction from the second magnetic plate 1158 toward the first magnetic plate 1156, that is, The density of magnetic flux lines φ3 from the north pole region of the magnet to the south pole region via the second magnetic plate 1158 and the first magnetic plate 1156 increases.

Furthermore, as the magnet 110 rotates up to 360 degrees from (H) to (I) in FIG. 5, the density of the magnetic flux lines φ3 from the second magnetic plate 1158 toward the first magnetic plate 1156 decreases. As the direction of the magnetic flux line φ3 is reversed every rotation of the magnet 110, the direction of the magnetic flux line flowing through the ferromagnetic wire 1152 of the large Barkhausen effect power generation unit 115 is reversed, and the power generation coil 1154 is As shown in 6(D), a pulsed power generation output is obtained.

One of the features of the present invention is that one disk-shaped magnet 110, which has only one pair of polarities N and S magnetized in the radial direction and is fixed to the rotating shaft 510, is connected to the analog signal of the magnetic sensor. It is used as a source and as a power generation device of the large Barkhausen effect power generation unit 115. The first magnetic plate and the second magnetic plate of the large Barkhausen effect power generation unit are mainly used to suppress the influence of magnetic field interference on the magnetic flux line φ1 toward the first TMR sensor and the magnetic flux line φ2 toward the second TMR sensor. It is configured to suppress the influence of magnetic field interference on the magnetic sensor by utilizing magnetic flux lines φ3 in an outer direction parallel to or close to the surface of the magnet. As a result, as one magnet rotates, as shown in FIGS. 5 and 6, the magnetic flux line φ3 direction in the first magnetic plate 1156 and the second magnetic plate 1158 of the large Barkhausen effect power generation unit The density greatly increases and decreases periodically, and the polarity and density of the magnetic flux line φ3 received by the first magnetic plate 1156 and the second magnetic plate 1158 also change. The combination of one magnet fixed to the end face of the rotating shaft 510 and the first magnetic plate 1156 and the second magnetic plate 1110 extending outward from both sides allows the large Barkhausen effect power generation unit 115 to have a compact configuration. However, large power output can be obtained.

Next, the configurations of the first magnetic plate and the second magnetic plate will be explained.
7A to 7E are diagrams showing an example of the relationship between the disc-shaped magnet and the first magnetic plate 1156 and the second magnetic plate 1158 in the first embodiment. As mentioned earlier, the first magnetic plate 1156 and the second magnetic plate 1158 are line-symmetrical with respect to the axis of symmetry on both sides of the magnet 110, and the magnet The first magnetic plate and the second magnetic plate extend apart from each other along both side surfaces of the magnet. Assuming that the diameter of the magnet is Dm and the length of the first magnetic plate and the second magnetic plate extending apart from each other to the outside of both sides of the magnet is Lm1, as an example, as shown in FIG. 7A, Lm1 is , approximately equal to Dm. As a result, a characteristic that periodically changes in both positive and negative directions can be obtained in 360 degrees of one rotation of the magnet, as shown in FIGS. 5 and 6.

However, in order to obtain a predetermined output from the large Barkhausen effect power generation unit 115, the characteristics shown in FIGS. good. Therefore, as shown in FIG. 7B, the length Lm2 in which the first magnetic plate and the second magnetic plate extend outward from both side surfaces of the magnet may be slightly shorter than Dm. Alternatively, even if Lm1 is slightly longer than Dm, a characteristic that changes periodically in both positive and negative directions can be obtained in 360 degrees of one rotation of the magnet. However, as the length increases, measures must be taken to ensure strength, so making it too long is not practical. Further, as shown in FIG. 7C, even if the first magnetic plate and the second magnetic plate are non-parallel, the inclination angle Θ between them is small (for example, within 10 degrees) and the condition is that they are line symmetrical. It is good if it meets the following. For the same reason, the first magnetic plate and the second magnetic plate may be slightly curved inward or outward from each other.
Furthermore, as shown in FIG. 7D, even if the length Ls1 extending outward from both side surfaces of the magnet is half of Dm, a periodic pattern of the same magnitude will occur on both the positive and negative sides in one 360-degree rotation of the magnet. characteristics can be obtained. Note that, as shown in FIG. 7E, when the length Ls2 is 3/4 of Dm, it is difficult to obtain a periodically changing characteristic, but it is possible to obtain a predetermined output from the large Barkhausen effect power generation unit 115. is possible.

Next, FIG. 7F is a diagram showing the characteristics of the first magnetic plate and the second magnetic plate in the first example. In large Barkhausen effect power generation, a pulse output is obtained by a sudden change in magnetic flux density from positive to negative or from negative to positive as a magnet rotates. On the contrary, a large magnetic flux density when the magnetic flux densities have the same polarity, for example, a large magnetic flux density at a position around 90 degrees or 270 degrees as shown in FIG. 6, does not contribute much to the output of large Barkhausen effect power generation. Therefore, it is desirable to configure the magnetic flux density of the first magnetic plate and the second magnetic plate to be saturated at positions around 90 degrees or 270 degrees.

Next, a configuration example of the circuit of the power supply unit in the first embodiment will be described with reference to FIG. 8A.
The main power supply 121 of the power supply unit 12 includes a main power supply section 1211 in which power supplied from, for example, a commercial power source is converted into DC power and controlled to a predetermined DC voltage Vcc, for example, 5V. This main power supply section 1211 supplies power to the output terminal 124 via a diode 1221.
The large Barkhausen effect power generation power source 122 is output from the large Barkhausen effect power generation unit 115 as a positive and negative pulse-like waveform at intervals of 180 degrees for each rotation of the rotating shaft. This power is supplied to the output terminal 124 as DC power at a predetermined voltage Vcc via the full-wave waveform circuit 1222, the smoothing circuit 1223, and the diode 1231.

The backup power supply 123 includes a current limiting circuit 1232, a capacitor 1233, and a voltage limiting circuit 1234, and supplies DC power of a predetermined voltage Vcc to the output terminal 124. Capacitor 1233 is individually supplied with power from both main power supply 121 and large Barkhausen effect power generation power supply 122 . The backup power supply 123 supplies power in place of the main power supply, and further functions as a power supply that supplies power to the rotary encoder 10 even in a power outage state. The current limiting circuit 1232 limits the current supplied to the capacitor 1233 when the motor rotation speed is high and the amount of electric power generated by the large Barkhausen effect power generation unit 115 is large, so that the capacitor 1233 is within the allowable range. This controls the accumulation of charge. For example, an electric double layer capacitor may be used as the capacitor 1233. The capacitor 1233 may be configured by connecting a plurality of capacitors in parallel in order to moderate the voltage drop.
The power supply line connected to the output terminal 124 of the power supply unit 12 is configured as three electrically independent lines, and is connected to the system control unit 14, the first TMR sensor signal processing unit 15, and the second TMR sensor signal processing unit 15. Power is supplied to the processing unit 16.

FIG. 8B is a diagram showing another example of the configuration of the circuit of the power supply unit 12.
In this power supply unit, the capacitor 1233 of the backup power supply 123 is configured by connecting a plurality of capacitors C1 (12331), C2 (12332), C3 (12333), and C4 (12334) in parallel. Capacitors C2, C3, C4 are connected to smoothing capacitor C0 via a plurality of Zener diodes Z2, Z3, Z4 having different Zener voltages (Vz), and as the voltage of the capacitor increases, capacitors C2, C3, C4 is configured to be sequentially charged to a voltage slightly higher than Vcc. Transistor switches SW1 (1236), SW2 (1237), and SW3 (1238) are provided between capacitors C1, C2, C3, and C4, and a control circuit (not shown) maintains the output voltage of capacitor C1 at Vcc. controlled so that

Electric power obtained by the large Barkhausen effect power generation unit 115 is stored in a capacitor 1233 that constitutes the backup power supply 123. The power of this backup power source 123 can be used as a power source for the rotary encoder instead of the main power source, and even for a long period of time even after a power outage of the main power source.
FIG. 9 is a time chart showing the operation of the power supply unit, and is a diagram showing an example of the relationship between the backup power supply and the output signal of the rotary encoder when the main power supply is in a normal state and then loses power.
Power is supplied to the rotary encoder from the main power supply only during startup. After startup, power is supplied from the backup power supply 123 to the rotary encoder by the large Barkhausen effect power generation power supply 122.
Even when the main power supply unit 1211 is unable to supply power at time t1 due to a power outage or failure, for example, power is supplied to the rotary encoder 10 from the large Barkhausen effect power generation power supply 122 that generates power as the rotating shaft rotates. .

As the rotational speed of the rotating shaft decreases over time after the power outage, the output of the large Barkhausen effect power generation decreases, and at time t2, it is no longer possible to supply DC power at a predetermined voltage Vcc to the backup power source. In this state, the electric charge stored in the capacitor 1233 of the backup power supply 123 supplies power of voltage Vcc to the rotary encoder 10.
Thereby, the rotary encoder 10 can generate and record information on the rotation angle of the rotary shaft for a long period of time, for example, until time t3 when the rotation of the rotary shaft completely stops.
Furthermore, even after the rotating shaft has stopped due to a power outage, if the rotating shaft is forcibly rotated by an external force, such as a human force, via the robot arm, the output of the large Barkhausen effect power generation and the capacitor will be 1233. Electric power is supplied to the rotary encoder 10 from time t4 to time t6 by the electric charge stored in the rotary encoder 10. Therefore, even if the rotating shaft is rotated by an external force after the rotating shaft has stopped due to a power outage or the like, information on the rotation angle of the rotating shaft is recorded.

FIG. 10 is a diagram showing the relationship between the rotation of the magnet and the output of the TMR sensor in the first embodiment. As the magnet rotates, the direction of magnetization of the free layer and pinned layer of the TMR sensor changes as the relationship between the north and south poles faces changes. Along with this, the TMR sensor outputs sine wave and cosine wave signals.

Next, the process of digitizing and absoluteizing the first TMR sensor signal in the first TMR sensor signal processing unit 15 will be described with reference to FIGS. 11, 12, and 13.
The first TMR sensor signal processing unit 15 acquires information on the number of poles of the motor and the origin of the rotation axis from the initial setting values (S1201).
As shown in FIG. 11(A), the first TMR sensor (TMR sensor) 111 generates a SIN wave and a COS wave for one period each at 360 degrees (mechanical angle) corresponding to one rotation of the rotation axis. A first analog signal of minutes is output. The data on the rotation angle (mechanical angle), amplitude, and rotation speed Nx of these first analog signals are processed by the analog signal processing section 151 of the first TMR sensor signal processing unit 15 and are related to the temperature Ta of the temperature sensor 13, etc. is attached and recorded in memory.

As shown in FIG. 11(B), the analog signal (Sin signal, Cos signal) is input to the AD converter 152, and is quantized and converted into a multi-divided digital signal by interpolation processing. , B-phase information, and these converted values are recorded in the EEPROM-1 in relation to the rotation speed Nx, rotation direction, temperature Ta, etc.

As shown in the flowchart of FIG. 12, the first TMR sensor signal processing unit 15 first obtains information on the origin of the rotation axis from the initial setting value (S1201). Further, AD conversion data of the first TMR sensor signal (Sin, Cos waves) is acquired from the EEPROM-1 (S1202). If the processing is absolute (YES in S1203), the first TMR sensor signal processing unit 15 further calculates the absolute values of the rotation direction and rotation angle based on the AD conversion data and origin information (S1204), and converts the absolute value The memory is assigned an address and recorded in the memory (S1205). Then, one-rotation absolute information is generated and recorded in the EEPROM 2 as one-rotation absolute data (S1206). Furthermore, multi-rotation absolute information is generated and recorded in the EEPROM 2 as multi-rotation absolute data (S1207).
In this way, as shown in FIG. 11(C), an absolute value for each forward/reverse rotation is generated and recorded in the EEPROM-2 together with data on the rotation speed Nx, temperature Ta, and rotation direction.

On the other hand, if the process is incremental (NO in S1203), the rise of the A phase and B phase is determined based on the information on the A phase and B phase shown in FIG. 11 (B) from the AD conversion data. (S1212), and generates U, V, and W phase data based on the width data of the A, B, and Z phases (S1213). Further, as shown in FIG. 13, the data of the A phase, B phase, Z phase, U, V, and W phases are assigned addresses and recorded in the EEPROM 2 as incremental data (S1214). This process is continued until the end of the operation.

In the rotary encoder in the first embodiment, the safety control unit 145 monitors the output status of the two systems of rotary encoder functions, and stops the operation of the rotary encoder if either rotary encoder function fails. Perform the necessary processing. In this way, the rotary encoder in the first embodiment is a safety encoder that has two systems of rotary encoder functions and a backup power source in addition to the main power source.
It should be noted that the configuration may be such that, when one of the functions of the two rotary encoders fails, the function of the rotary encoder that is not malfunctioning is continued to be used within a range that satisfies safety and other predetermined conditions.

Next, a second embodiment of the present invention will be described with reference to FIG. 14. In this embodiment, the first magnetic plate 1156 and the second magnetic plate 1158 of the large Barkhausen effect power generation unit 115 are spaced apart from each other on the outside of both sides of the magnet 110 and extend in a ring shape. The gap Ga between the first magnetic plate 1156 and the second magnetic plate 1158 is constant. With this configuration, changes in the opposing areas of the first magnetic plate 1156, the second magnetic plate 1158, and the N-pole region and the S-pole region of the magnet 110 become gradual, and the output of the large Barkhausen effect power generation unit 115 changes gradually. becomes more regular. The length of the ring-shaped portion in the circumferential direction can be selected as appropriate, as shown in FIGS. 7A to 7E. Further, the protruding direction of the tip of each open end may face toward the center of the magnet 110.

Next, a third embodiment of the present invention will be described with reference to FIGS. 15 and 16.
In the third embodiment, an optical sensor is used in place of the second TMR sensor of the first embodiment.
FIG. 15 is a functional block diagram of a rotary encoder, and FIG. 16 is a longitudinal sectional view showing an example of the configuration of a TMR sensor, an optical sensor, and a power supply unit in the third embodiment.
In FIG. 15, the configuration and function of the TMR sensor signal processing unit 15 that processes the signal of the TMR sensor 111 are the same as the configuration and function of the first TMR sensor signal processing unit 15 of the first embodiment. The optical sensor signal processing unit 17 that processes the signal of the optical sensor 118 includes a detection processing section 171 for a light receiving sensor (incremental signal and absolute signal), an AD converter 172, and a digital signal processing section 173.

As shown in FIG. 16, below the magnet 110, a disk 119 made of a resin material is fixed to the rotary shaft 510 via a holding part 1104. An absolute scale 116 and an incremental scale 117 are formed for detecting. On the other hand, the printed circuit board 19 is provided with an optical sensor 118, and in order to detect each pattern of the absolute scale 116 and the incremental scale 117, the optical sensor 118 uses a light emitting element that irradiates the pattern with detection light and a light emitting element that irradiates the pattern with detection light. It includes a light-receiving element (light-receiving sensor) that receives light. Note that a transmission type optical sensor may be used as the optical sensor.

Returning to FIG. 15, in the AD converter 172 of the optical sensor signal processing unit 17, similar to the TMR sensor signal processing unit 15, the sampling data of the analog signal is transferred to the 64-bit AD converter 172 (ADC-1 (incremental ) 1721 and ADC-2 (absolute) 1722) and are converted into digital values, and these converted values are recorded in EEPROM-3 (1723) as time series data.

In the rotary encoder of the third embodiment, as in the rotary encoder of the first embodiment, one disc-shaped magnet 110 having only one set of polarities N and S is used as the analog signal source of the magnetic sensor. , it can be used as a power generation device for the large Barkhausen effect power generation unit 115. As one magnet rotates, as shown in FIGS. 5 and 6, the density of the magnetic flux line φ3 direction in the first magnetic plate 1156 and the second magnetic plate 1158 of the large Barkhausen effect power generation unit becomes periodic. The polarity and density of the magnetic flux line φ3 received by the first magnetic plate 1156 and the second magnetic plate 1158 change accordingly. This one magnet 110 is fixed to the end face of the rotating shaft 510, and it is possible to obtain a large power generation output while making the large Barkhausen effect power generation unit 115 compact.

The rotary encoder of the present invention is a safety encoder based on one magnet fixed to a rotating shaft, and can be used in combinations other than the combination of a pair of TMR sensors or the combination of a TMR sensor and an optical sensor as described in the embodiment. , various combinations can also be adopted. For example, a combination of a TMR sensor and a GMR sensor, an AMR sensor and a TMR sensor, a pair of AMR sensors, a pair of GMR sensors, a pair of Hall element sensors, or a TMR sensor and a Hall element sensor may be used.
Further, the rotary encoder of the present invention may be configured to include the function of a single rotary encoder using a magnetic sensor based on one magnet, and a large Barkhausen effect power generation unit.

An encoder according to a fourth embodiment of the present invention, which is a combination of a GMR sensor and an optical sensor, will be described below with reference to FIGS. 17 and 18.
FIG. 17 is a longitudinal sectional view showing a configuration example of a magnetic sensor and a power supply unit in the fourth embodiment, and FIG. 18 is a plan view of an encoder housing.
In the large Barkhausen effect power generation unit 115 of this embodiment, the first magnetic plate 1156 and the second magnetic plate 1158 connected to both ends of the ferromagnetic wire 1152 are connected to each other in the direction of the axis O _S - O _S of the rotating shaft 510. It extends to a position midway between the magnet 110 and the GMR sensor 1110, and the tip of each magnetic plate extends to near the outer periphery of the magnet 110.
The tips of each magnetic plate extend to near the outer periphery on the surface of the magnet 110 in the same relationship as shown in FIGS. 7A to 7E. That is, on the surface of the magnet 110, the center lines O _G1 and O _G2 of these magnetic plates extend in parallel along the axis of symmetry, and these magnetic plates extend near both side surfaces of the magnet. It has a line-symmetrical shape on the surface of .
In this embodiment, a GMR sensor signal processing unit is provided in place of the TMR sensor signal processing unit 15 in the functional block diagram of the rotary encoder of the third embodiment shown in FIG. It has the same functions as the optical sensor signal processing unit 17 of the embodiment. The GMR sensor outputs sine wave and cosine wave signals. This GMR sensor signal processing unit also has the same function as the TMR sensor signal processing unit 15 in the third embodiment, and the sampling data of the analog signal is sent to the AD converter (ADC-1 (incremental), ADC-1 (incremental), 2 (absolute)) and converted into digital values, and these converted values are recorded in the EEPROM as time series data.

In this embodiment, a GMR sensor is used as the magnetic sensor of the rotary encoder, and the first magnetic plate and the second magnetic plate are configured to extend over the surface of the magnet 110 and to the vicinity of its outer periphery. This ensures the fluctuation of the magnetic flux line φ3 necessary for the large Barkhausen effect power generation unit, and also accepts the magnetic flux line φ3 mainly parallel to the surface of the magnet or in the outer direction close to it, so that the GMR sensor 1110 The effects of magnetic field interference can be suppressed. As a result, it is possible to provide an encoder having the functions of two independent rotary encoders and having a compact configuration.
Assuming that the gap between the surface of the magnet 110 and each magnetic plate in the axial direction is G2, and the gap between each magnetic plate and the GMR sensor 1110 is G3, as an example, the diameter of the rotating shaft 510 is 6.0 to 8. When the magnet diameter is about 0 mm and the diameter of the magnet is about 5.0 to 10.0 mm, it is desirable that G2 and G3 are each about 0.5 to 3.0 mm.
This embodiment is more susceptible to the influence of magnetic field interference caused by the first magnetic plate and the second magnetic plate than the first to third embodiments. Therefore, the influence of magnetic field interference by the first magnetic plate and the second magnetic plate on the output of the GMR sensor at each rotational position is measured in advance, and correction data for each rotational position is generated to correct this influence, and system control is performed. It may be configured to be held in the initial setting section 141 of the unit 14.
According to this embodiment, a rotary encoder that requires high precision or is used auxiliary, is equipped with two systems of rotary encoders including a magnetic encoder, and is inexpensive and has a compact configuration. The servo control device used can be provided.

The rotary encoder of the present invention can also be employed in other types of motors, such as stepping motors. Moreover, it can be widely applied to various rotating electric devices such as synchronous motors and induction motors. Furthermore, the present invention can also be applied to servo control devices using these rotating electric devices.

10 Rotary encoder 11 TMR sensor unit 110 Magnet 111 First TMR sensor 1110 GMR sensor 112 Second TMR sensor 115 Large Barkhausen effect power generation unit 1156 First magnetic plate 1158 Second magnetic plate 116 Absolute scale 117 Incremental scale 118 Optical sensor 12 Power unit 121 Main power supply 122 Large Barkhausen effect power generation power supply 123 Backup power supply 13 Temperature sensor 14 System control unit 141 Initial setting section 144 Encoder input/output control unit 145 Safety control unit 147 Serial/parallel signal transmission/reception unit 15 First TMR sensor signal processing unit 151 1 TMR sensor analog signal processing unit 152 AD converter 153 Digital signal processing unit 16 2nd TMR sensor signal processing unit 161 2nd TMR sensor analog signal processing unit 162 AD converter 163 Digital signal processing unit 17 Optical sensor signal processing unit 18 FPGA or ASIC
19 Printed circuit board 510 Rotation axis O _mgR -O _mgR Axis of symmetry

Claims (10)

A rotary encoder comprising a magnet fixed to a rotating shaft and a function of generating information regarding the rotation angle and rotation direction of the rotating shaft from the output of a magnetic sensor placed opposite the magnet, the rotary encoder comprising:
The rotary encoder is equipped with a large Barkhausen effect power generation unit as a power supply unit,
The magnet fixed to the rotating shaft is a disc-shaped magnet in which a set of N-pole region and S-pole region are formed in the radial direction with a boundary line passing through the center of the magnet. the north pole region and the south pole region form one flat surface;
The large Barkhausen effect power generation unit includes a ferromagnetic wire, a power generation coil, and a first magnetic plate and a second magnetic plate connected to both ends of the ferromagnetic wire,
The first magnetic plate and the second magnetic plate extend from both ends of the ferromagnetic wire to the outside of both side surfaces of the magnet with the magnet in between,
The first magnetic plate and the second magnetic plate extend apart from each other along both side surfaces of the magnet,
A rotary encoder characterized in that the first magnetic plate and the second magnetic plate have a line-symmetrical shape with the magnet sandwiched therebetween in the axial direction of the rotating shaft. A rotary encoder comprising a magnet fixed to a rotating shaft and a function of generating information regarding the rotation angle and rotation direction of the rotating shaft from the output of a magnetic sensor placed opposite the magnet, the rotary encoder comprising:
The rotary encoder is equipped with a large Barkhausen effect power generation unit as a power supply unit,
The magnet fixed to the rotating shaft is a disc-shaped magnet in which a set of N-pole region and S-pole region are formed in the radial direction with a boundary line passing through the center of the magnet. the north pole region and the south pole region form one flat surface;
The large Barkhausen effect power generation unit includes a ferromagnetic wire, a power generation coil, and a first magnetic plate and a second magnetic plate connected to both ends of the ferromagnetic wire,
The first magnetic plate and the second magnetic plate extend from both ends of the ferromagnetic wire to a position between the magnet and the magnetic sensor in the axial direction of the rotating shaft,
The first magnetic plate and the second magnetic plate extend from both ends of the ferromagnetic wire onto the surface of the magnet to near both side surfaces of the magnet,
The first magnetic plate and the second magnetic plate extend apart from each other on the surface of the magnet,
A rotary encoder, wherein the first magnetic plate and the second magnetic plate have a line-symmetrical shape on the surface of the magnet. In claim 1 or 2,
The first magnetic plate and the second magnetic plate are configured to mainly accept lines of magnetic flux in an outer direction parallel to or close to the surface of the magnet, and to suppress the influence of magnetic field interference on the magnetic sensor. A rotary encoder characterized by: In claim 1 or 2,
The other ends of the first magnetic plate and the second magnetic plate on the side opposite to the ferromagnetic wire are open ends with the magnet in between, and each of the open ends protrudes in a tapered shape. A rotary encoder characterized by: In claim 1 or 2,
The position of one end on the boundary line between the north pole region and the south pole region of the magnet is an origin position (Z0),
The first magnetic plate and the second magnetic plate are plate-shaped or rod-shaped members extending along an axis of symmetry (O _mgR −O _mgR ) perpendicular to the boundary line at the origin position. rotary encoder. In claim 1 or 2,
A rotary encoder characterized in that the ferromagnetic wire and the power generation coil of the large Barkhausen effect power generation unit are held in an encoder housing having a hollow portion. In claim 6,
A rotary encoder comprising a backup power source including a capacitor charged by the large Barkhausen effect power generation unit. In claim 1,
An analog signal that is an output of the magnetic sensor disposed facing the magnet is converted into an analog signal, and includes two types of information, an absolute signal and an incremental signal, regarding the rotation angle and the rotation direction of the rotation shaft. Equipped with a magnetic sensor signal processing unit that generates digital data,
The magnetic sensor and the processing unit are held in an encoder housing having a hollow part,
The magnetic sensor includes a first TMR sensor and a second TMR sensor,
The first TMR sensor is installed on the printed circuit board held by the encoder housing at a position facing the magnet, and the second TMR sensor is installed on the back side of the first TMR sensor on the printed circuit board,
The rotary encoder is characterized in that the rotary encoder has the functions of two independent systems of rotary encoders. In claim 1,
It includes a TMR sensor as the magnetic sensor and an optical sensor,
The TMR sensor is installed at a position facing the magnet on a printed circuit board held in an encoder housing having a hollow part,
An incremental scale and an absolute scale of the optical sensor are formed on a disk fixed to the rotating shaft,
A light emitting element and a light receiving element of the optical sensor are held in the encoder housing,
The rotary encoder is characterized in that the rotary encoder has the functions of two independent systems of rotary encoders. A servo control device using rotating electric equipment,
A servo control device, wherein the rotating electric device includes the rotary encoder according to claim 1 or 2.

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