JP2005164551A - Magnetic type linear absolute encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic type linear absolute encoder with a simple structure, capable of being made compact and light in weight and of surely detecting the absolute position of a position object to be detected. <P>SOLUTION: The magnetic type linear absolute encoder 1 is provided with a long magnetized scale 12 for detecting positions; a magnetic sensor 11 which detects a magnetic field generated by the position detecting scale 12 and convert it electromagnetically; and a data control section 70, which determines the absolute position of the position detection object, based on detection results of the magnetic sensor 11. The position-detecting scale 12 is made up so that the strength of the magnetic field is gradually decreased or increased, along its longitudinal direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic linear absolute encoder.

Magnetic absolute encoders for detecting the absolute position of a moving object that rotates or moves linearly are known. In such an encoder, for example, as shown in FIG. 6, the drum 200 fixed to the rotary shaft 100, the magnetic recording medium 300 formed on the side surface thereof, and the substrate 400 are formed, and the MR element 500 and the conductor terminal are formed. A detection head having 600, a lead wire 700 connected to the conductor terminal 600, and a drive detection circuit 800 having an output terminal to the outside. Five magnetic pattern rows n1 to n5 are written in the magnetic recording medium 300, and a magnetic field leaking from these magnetic patterns n1 to n5 acts on the corresponding MR element 500 (for example, see Patent Document 1).
However, in such an encoder, a sensor (MR element) is required for each pattern row, and if the number of pattern rows (layers) increases, the number of corresponding sensors increases and the magnetization pattern also becomes multi-layered and complicated. There was a problem that would become large.

JP-A-1-145520

  The object of the present invention is to simplify the structure, to reduce the size and weight, and to reliably detect the absolute position of the position detection target. The object is to provide a magnetic linear absolute encoder.

Such an object is achieved by the present invention described below.
The magnetic linear absolute encoder of the present invention includes a magnetized long position detecting scale,
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor,
The position detection scale is configured such that the strength of the magnetic field gradually decreases or gradually increases along the longitudinal direction thereof.
As a result, the structure can be simplified, the size and weight can be reduced, and the absolute position of the position detection target can be reliably detected.

The magnetic linear absolute encoder of the present invention includes a magnetized long position detecting scale,
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor,
The position detection scale is configured such that the strength of the magnetic field gradually decreases along the longitudinal direction, the direction of the magnetic field is reversed in the middle, and the strength of the magnetic field is gradually increased.
As a result, the structure can be simplified, the size and weight can be reduced, and the absolute position of the position detection target can be reliably detected.

The magnetic linear absolute encoder of the present invention includes a magnetized long position detecting scale,
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor and a calibration curve indicating a relationship between the detection result and the absolute value of the position detection target. And
The position detection scale is configured such that the strength of the magnetic field gradually decreases or gradually increases along the longitudinal direction thereof.
As a result, the structure can be simplified, the size and weight can be reduced, and the absolute position of the position detection target can be detected more reliably.

The magnetic linear absolute encoder of the present invention includes a magnetized long position detecting scale,
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor and a calibration curve indicating a relationship between the detection result and the absolute value of the position detection target. And
The position detection scale is configured such that the strength of the magnetic field gradually decreases along the longitudinal direction, the direction of the magnetic field is reversed in the middle, and the strength of the magnetic field is gradually increased.
As a result, the structure can be simplified, the size and weight can be reduced, and the absolute position of the position detection target can be detected more reliably.

In the magnetic linear absolute encoder of the present invention, the calibration curve is preferably set in advance.
As a result, the absolute position of the position detection target can be reliably detected.
The magnetic linear absolute encoder of the present invention has magnetic field detection means for detecting a magnetic field in the vicinity of the magnetic sensor, and is configured to correct the calibration curve based on the detection result of the magnetic field detection means. preferable.
Thereby, disturbance can be removed and the absolute position of the position detection target can be detected more reliably.

The magnetic linear absolute encoder of the present invention preferably has a temperature detecting means for detecting the temperature of the magnetic sensor, and is configured to correct the calibration curve based on the detection result of the temperature detecting means.
Thereby, disturbance can be removed and the absolute position of the position detection target can be detected more reliably.

In the magnetic linear absolute encoder according to the aspect of the invention, it is preferable that the direction of the magnetic field is reversed at substantially the center in the longitudinal direction of the position detection scale.
Thereby, the absolute position of the position detection target can be easily detected.
In the magnetic linear absolute encoder of the present invention, it is preferable that the position detection scale is magnetized in two poles so that one end side is an N pole and the other end side is an S pole in the longitudinal direction.
Thereby, the absolute position of the position detection target can be easily detected.

In the magnetic linear absolute encoder of the present invention, the position detection scale has a first part that is an N pole and a second part that is an S pole, and the first part with respect to the area of the second part. It is preferable that the ratio of the area of the part gradually increases or decreases along the longitudinal direction of the position detection scale.
As a result, it is possible to easily cope with environmental noise and to detect the absolute position of the position detection target more reliably.

In the magnetic linear absolute encoder of the present invention, the length of the first portion in a direction substantially perpendicular to the longitudinal direction of the position detection scale gradually increases along the position detection scale, and the position detection It is preferable that the length of the second portion in a direction substantially perpendicular to the longitudinal direction of the scale for use is gradually reduced along the scale for position detection.
As a result, the absolute position of the position detection target can be detected more easily and reliably.

Hereinafter, a magnetic linear absolute encoder of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a plan view showing a first embodiment of a magnetic linear absolute encoder of the present invention. In the following, for convenience of explanation, the right side in FIG. 1 is referred to as “right”, the left side as “left”, the upper side as “upper”, and the lower side as “lower”.

As shown in FIG. 1, the magnetic linear absolute encoder 1 is a linear encoder, and includes a magnetic sensor 11, a position detection scale 12, and a data control unit (position detection means) 10. Hereinafter, each of these components will be described sequentially.
The position detection scale 12 has a strip shape (substantially rectangular shape), that is, a long shape in plan view. The long shape includes not only a straight shape but also a curved or bent shape.

  For example, the position detection scale 12 is magnetized in two poles so that the upper side (one end side) in FIG. 1 is an N pole and the lower side (the other end side) is an S pole. Thus, the N-pole magnetic field (magnetic flux) gradually decreases, the magnetic field at the center becomes substantially zero, and the S-pole magnetic field gradually increases from the center toward the lower side. That is, the magnetic field strength (magnitude) and polarity change along the position detection scale 12.

As a result, the strength and polarity of the magnetic field detected by the magnetic sensor 11 change as the position detection scale 12 moves. Specifically, the strength of the magnetic field detected by the magnetic sensor 11 gradually decreases along the longitudinal direction of the position detection scale 12, the magnetic field detected at the center becomes substantially 0, and the polarity detected by the magnetic sensor 11 is As it reverses, the strength of the magnetic field gradually increases.
The magnetic sensor 11 has a sensor unit 112 that detects and electromagnetically converts a magnetic field generated from the position detection scale 12. Examples of the magnetic sensor 11 include a magnetoresistive element.

When the magnetic field generated from the position detection scale 12 is detected by the sensor unit 112, a current having a magnitude and polarity corresponding to the magnetic field detected by the sensor unit 112 is output by electromagnetic conversion. This signal is converted into a voltage, that is, an analog signal, for example, via a resistor (not shown) provided inside the magnetic sensor 11.
Further, for example, as shown in FIG. 2, by using this resistor as a variable resistor and applying a predetermined voltage between A and B, the range of the value of the analog signal output from the magnetic sensor 11 is set to a predetermined range. It can also be adjusted.
The data control unit 70 includes an amplifier 71, an A / D converter 72, and a CPU 73.

The amplifier 71 is connected to the output side of the magnetic sensor 11. The amplifier 71 amplifies the input analog signal and outputs it. An A / D converter 72 is connected to the output side of the amplifier 71.
The A / D converter 72 converts the input analog signal into a digital signal and outputs it. A CPU 73 is connected to the output side of the A / D converter 72.
The CPU 73 performs a calculation based on the input digital signal, and stores the calculation result, table data, and the like in a storage unit provided in the CPU 73.

Next, a measurement system 50 using the magnetic linear absolute encoder 1 will be described. FIG. 3 is a plan view illustrating a configuration example of the measurement system 50.
As shown in FIG. 3, the measurement system 50 includes a linear actuator 2 and a magnetic linear absolute encoder 1.
The linear actuator 2 includes a plate-like base 21, a plate-like base 22, a plate-like slider (position detection target) 23, and a vibrating body 6. The base 21, the base 22, the slider 23, and the vibrating body 6 are installed so as to be parallel to each other (including a case where a part thereof overlaps the surface direction).

  The base 22 is installed at the center of the base 21 so as to be movable in the left-right direction in FIG. In this case, a pair of guide pins (not shown) are erected along the left-right direction in FIG. 3 at the center of the base 21, and a pair of not-shown long pins in the left-right direction in FIG. Holes are formed along the left-right direction in FIG. Each guide pin is inserted into a corresponding slot. Thereby, the base 22 is guided by the guide pin, and can move in the left-right direction in FIG. 3 along the elongated hole.

  The base 22 is provided with a vibrating body 6 that rotationally drives a rotor (driven body) 41 described later. The vibrating body 6 has a convex portion (contact portion) 26 and a pair of arm portions 28, 28, and the arm portion 28 is arranged on each arm portion 28 with respect to the base 22 so that the convex portion 26 faces the right side in FIG. 3. It is fixed by a bolt 27 inserted into a formed hole (not shown). Thereby, the vibrating body 6 is supported by each arm part 28 so that it can vibrate. The vibrating body 6 will be described in detail later.

Further, a pair of spring retaining pins 31 are erected on the right end (corner) of the base 21 in FIG. On the other hand, the base 22 is formed with a pair of spring hooks 32 and 32. One spring hook 32 is provided on the upper side of the base 22 in FIG. 3, and the other spring hook 32 is provided on the lower side of the base 22 in FIG. 3.
Then, the corresponding spring stopper pin 31 and the spring hook portion 32 are respectively installed in a state where the coil spring (biasing means) 33 is extended (extended state). That is, each of the coil springs 33 is hung (fixed) at one end thereof on the spring hooking portion 32 of the base 22, and the other end is attached (fixed) to the spring stopper pin 31 of the base 21. ).

The base 21 is urged toward the right side in FIG. 3 by the elastic force (restoring force) of each coil spring 33, and the convex portion 26 of the vibrating body 6 abuts on and is pressed against the outer peripheral surface of the driven body described later. The
The magnetic sensor 11 is provided on the base 21. The magnetic sensor 11 is provided between the base 21 and the slider 23 in the vicinity of the upper coil spring 33 in FIG. A position detecting scale 12 is provided on the surface of the slider 23 facing the base 21.

  The position detection scale 12 has a band shape (substantially rectangular shape) in plan view, and is provided such that the longitudinal direction thereof substantially coincides with the moving direction of the slider. The position detection scale 12 has a length so that the magnetic sensor 11 detects the magnetic field at one end in the longitudinal direction of the position detection scale 12 when the slider 23 moves to the maximum in FIG. The various conditions such as the length are set so that the magnetic field at the other end in the longitudinal direction of the position detecting scale 12 is detected when the position moves to the lower side in FIG. .

  In addition, a rotor 41 is rotatably installed at an end portion of the base 21 on the right side in FIG. 3 and in a central portion in the vertical direction in FIG. The rotor 41 includes a cylindrical member 42 having a substantially cylindrical shape, and a driven body 43 fixed (fixed) to the outer side (outer periphery) of the cylindrical member 42. The driven body 43 has a substantially ring shape (annular shape) and is located at a position (base end side) corresponding to the vibrating body 6.

A pinion gear is formed on the outer peripheral surface of the rotor 41 on the tip side. Thus, when the rotor 41 rotates, the driven body and the pinion gear rotate integrally.
Further, the diameter (outer diameter) of the portion (rotating body) where the pinion gear of the rotor 41 is formed is set smaller than the diameter (outer diameter) of the driven body, thereby configuring a speed reduction mechanism. .
Also, two rollers 29 having grooves are rotatably installed at the left end (corner) of the base 21 in FIG.

The slider 23 is located in the groove of these rollers 29, is sandwiched between the rollers 29 and the rotor 41, and is installed so as to be movable in the vertical direction in FIG. That is, the slider 23 is regulated by each roller 29 and the rotor 41 so that the moving direction thereof is the vertical direction in FIG. 3 and the posture is held constant.
The slider 23 has a substantially rectangular frame shape. That is, a substantially square opening is provided in the center of the slider 23.

A rack gear 231 that meshes with a pinion gear 44 provided on the rotor 41 is formed on the end face on the right side in FIG. 3 of the slider 23 along the moving direction of the slider 23. The rack gear 231 and the pinion gear 44 convert the rotational motion of the rotor 41 into linear motion of the slider 23. Therefore, the rack gear 231 and the pinion gear 44 constitute a rotation / movement conversion mechanism.
In addition, protrusions 232 are formed at both corners on the right side of the slider 23 in FIG. These protrusions 232 prevent (prevent) the slider 23 from being detached.

Next, the configuration of the vibrating body 6 and the operation (operation) of the linear actuator 2 will be described.
The vibrating body 6 has a substantially rectangular plate shape. The vibrating body 6 is configured by laminating a plate-like electrode, a plate-like piezoelectric element, a reinforcing plate, a plate-like piezoelectric element, and a plate-like electrode in this order.
Each piezoelectric element has a rectangular shape, and expands and contracts in the longitudinal direction when a voltage is applied. The constituent material of the piezoelectric element is not particularly limited. For example, lead zirconate titanate (PZT), crystal, lithium niobate, barium titanate, lead titanate, lead metaniobate, polyvinylidene fluoride, lead zinc niobate Various types such as lead scandium niobate can be used.

  These piezoelectric elements are respectively fixed to both surfaces of the reinforcing plate. The reinforcing plate has a function of reinforcing the entire vibrating body 6 and prevents the vibrating body 6 from being damaged by over-amplitude, external force, or the like. The material of the reinforcing plate is not particularly limited as long as it is an elastic material (that can be elastically deformed). For example, various metal materials such as stainless steel, aluminum or aluminum alloy, titanium or titanium alloy, copper or copper-based alloy are used. Preferably there is.

The reinforcing plate is preferably thinner (smaller) than the piezoelectric element. Thereby, the vibrating body 6 can be vibrated with high efficiency.
The reinforcing plate also has a function as a common electrode for each piezoelectric element, and an AC voltage is applied to each piezoelectric element by the corresponding electrode and the reinforcing plate. That is, the vibrating body 6 is connected to a drive control circuit (not shown), and an AC voltage is applied by the drive control circuit. For example, the number, shape, arrangement, etc. of the electrodes can be appropriately set according to various conditions.

Moreover, the convex part (contact part) 26 is integrally formed in the right end part in FIG. 3 of a reinforcement board.
The reinforcing plate is integrally formed with a pair (two) of arm portions 28 having elasticity (flexibility). The pair of arm portions 28 are substantially perpendicular to the longitudinal direction of the reinforcing plate in a direction substantially perpendicular to the longitudinal direction and project in opposite directions through the reinforcing plate (vibrating body 6) (see FIG. 3 are provided symmetrically in the vertical direction.

The piezoelectric element repeatedly expands and contracts in a predetermined direction when an AC voltage is applied. Therefore, when an AC voltage having a predetermined frequency is applied to a predetermined electrode, the vibrating body 6 is minute in a predetermined mode (resonance mode). The convex portion 26 vibrates in a predetermined pattern (for example, combined vibration of longitudinal vibration and bending vibration).
Due to the vibration of the vibrating body 6, a rotational force (driving force) in a predetermined direction is repeatedly applied (applied) to the driven body 43 from the convex portion (via the convex portion), and the rotor 41 rotates in the predetermined direction. . The rotational motion of the rotor 41 is converted into the linear motion of the slider 23 by the pinion gear 44 provided on the rotor 41 and the rack gear 231 provided on the slider 23, and the slider 23 is guided to each roller 41. And move in a predetermined direction.

  On the other hand, when the vibrating body 6 is excited so that the vibration is reversed, a rotational force in the reverse direction to the driven body 43 is repeatedly applied from the convex portion 26, and the rotor 41 rotates in the reverse direction. The rotational motion of the rotor 41 is converted into the linear motion of the slider 23 by the pinion gear 44 provided in the rotor 41 and the rack gear 231 provided in the slider 23, and the slider 23 is guided to each roller 29. And move in the opposite direction.

Hereinafter, the operation (operation) of the measurement system 50 will be described based on the flowchart shown in FIG. This action is always performed while power is supplied to the measurement system 50 and the actuator can be driven. Hereinafter, each step will be described.
First, when the measurement system 50 is activated, whether or not to perform a calibration operation of a calibration curve indicating the relationship between the strength of the magnetic field detected by the magnetic sensor 11 and the absolute position of the slider (position detection scale) 23. Is determined (step S101). When the calibration is performed, the process proceeds to step S102, and when the calibration is not performed, the process proceeds to step S104.

  When calibration is performed in step S101, the position detection scale 12 is sampled by the A / D converter 72. Specifically, for example, the user (operator) moves the slider 23 of the linear actuator 2 at regular intervals. Thus, the data control unit 70 inputs the analog signal output from the magnetic sensor 11 to the amplifier 71, amplifies the analog signal by the amplifier 71, and inputs the amplified analog signal to the A / D converter 72. The A / D converter 72 converts an analog signal into a digital signal and inputs it to the CPU 73. The CPU 73 stores the digital signal in a predetermined storage area of the storage unit (step S102).

Further, the user inputs the position data of the position detection scale 12 corresponding to the analog signal output from the magnetic sensor 11 to the CPU 73. The CPU 73 creates a calibration curve based on the relationship between the digital signal and the position (step S103) and stores it in the storage unit. The calibration curve may be a table or a mathematical expression. Hereinafter, a case where a table is typically used as the calibration curve will be described.
At this time, the temperature and magnetic field at the time of sampling are measured using a temperature sensor (temperature detection means) and a magnetic field sensor (magnetic field detection means) (not shown) and stored in the storage unit. The magnetic sensor 11 may also serve as the magnetic field sensor described above.

  If calibration is not performed in step S101, the position detection scale 12 is sampled by the A / D converter 72. Specifically, the data control unit 70 inputs the analog signal output from the magnetic sensor 11 to the amplifier 71, amplifies the analog signal by the amplifier 71, and outputs the amplified signal to the A / D converter 72. The A / D converter 72 converts the analog signal into a digital signal and outputs it to the CPU 73. The CPU 73 stores the digital signal in a predetermined storage area of the storage unit (S104).

  Thereafter, the CPU 73 extracts the table stored in the storage unit in step S103 (step S105), and calculates the position using this table and the stored digital signal. (Step S106). The position information obtained by these processes is stored in the storage unit (step S107). Thereafter, the process proceeds to step S101, and the same processing is repeated again.

As described above, according to the magnetic linear absolute encoder 1 of the present invention, the magnetic field strength at the magnetic sensor 11 at a predetermined position of the position detection scale 12, that is, the electromagnetically converted voltage (the detected magnetic field) The absolute position of the slider 23 can be detected easily and accurately.
In the present embodiment, since only one magnetic sensor is used, the structure of the encoder can be simplified, and the entire apparatus can be easily downsized.

In addition, the present invention has an advantage that the table can be corrected according to a change in temperature. That is, the magnetic linear absolute encoder of the present invention can adjust the table according to the change in the output voltage from the magnetic sensor that changes according to the temperature of the resistance in the magnetic sensor.
In the magnetic linear absolute encoder 1, a correction formula for correcting the table is obtained as follows, for example. First, the CPU 73 obtains a coefficient Kb corresponding to the temperature at the time of the previous temperature correction (the first temperature correction is at the time of start-up calibration) from a predetermined equation or a calibration curve such as predetermined table data. This calibration curve is obtained in advance by experiments and stored in the storage unit.
The Kb may be obtained by calculation.

Next, the CPU 73 acquires the temperature information t of the resistance from the temperature sensor 8 and similarly obtains the coefficient Ka.
Then, the CPU 73 corrects the table (that is, the relationship between the voltage to be maintained and the position) based on the coefficients Ka and Kb. This correction is performed by, for example, the following formula (1).
LUT (n + 1) = Ka / Kb × LUT (n) (1)

  Here, LUT indicates each value in the table, and n indicates the number of corrections. When correction is performed in this way, when the temperature of the resistance is high, it is preferable to correct the table so that the displacement of the position becomes smaller than the digital amount of the digital signal input to the table. Adjustment of the table is appropriately performed before the magnetic linear absolute encoder is operated, during the operation of the magnetic linear absolute encoder, or the like.

  Thus, in the magnetic linear absolute encoder of the present invention, the table can be appropriately adjusted according to the temperature of the resistance. As a result, the absolute position of the slider with respect to the magnetic field can be accurately detected even if the temperature of the resistance is different or the temperature changes. That is, the magnetic linear absolute encoder of the present invention can suitably prevent the absolute position of the slider from changing between when it is hot and when it is cold.

  In the present invention, the table can be corrected according to the change in the magnetic field in the vicinity of the sensor unit in the same manner as described above. In this case, for example, Ka and Kb are obtained from a table representing the relationship between the magnetic field strength and the temperature stored in the storage unit of the CPU 73, the relationship between the magnetic field strength and the temperature, or the like. Thereby, in the magnetic linear absolute encoder of the present invention, even if the strength of the magnetic field in the vicinity of the sensor unit is different for each use, or even when the environment suddenly changes, the position of the position detection target is It can be detected reliably and accurately.

In the present embodiment, the magnetic field strength is configured to continuously change along the position detection scale. However, the present invention is not limited thereto, and for example, the magnetic field strength is configured to change stepwise. May be.
Further, in this embodiment, the N pole is provided on the upper side in FIG. 1 and the S pole is provided on the lower side. However, the present invention is not limited to this, and for example, the S pole may be provided on the upper side in FIG. .

Next, a second embodiment of the magnetic linear absolute encoder of the present invention will be described.
FIG. 5 is a plan view showing a second embodiment of the magnetic linear absolute encoder of the present invention.
Hereinafter, the magnetic linear absolute encoder 1 according to the second embodiment will be described focusing on the differences from the first embodiment described above, and the description of the same matters will be omitted.

The magnetic linear absolute encoder 1 of the second embodiment is different in the shape of the position detection scale and the arrangement (pattern).
As shown in FIG. 5, the position detecting scale 12 of the magnetic linear absolute encoder 1 of the second embodiment includes an N pole portion 13 that is a first portion having a substantially triangular shape in a plan view and a substantially triangular shape in a plan view. One S pole part 14 which is the second part of the shape is provided, and each has a belt-like shape (substantially rectangular shape) in which they are stacked in opposite directions, that is, a long shape. That is, the position detection scale 12 has a band shape in plan view, and is provided with an N pole portion 13 and an S pole portion 14 through one diagonal line thereof. With this configuration, the length of the S pole portion 13 in the direction substantially perpendicular to the direction from the upper side to the lower side in FIG. 5 of the position detection scale 12 gradually increases along the position detection scale. The length of the N pole portion 13 in the direction substantially perpendicular to the lower direction gradually decreases. That is, the ratio of the area of the S pole portion 14 to the area of the N pole portion 13 of the position detection scale 12 gradually increases along the longitudinal direction of the position detection scale 12.

According to this magnetic linear absolute encoder 1, the same effect as the magnetic linear absolute encoder 1 of the first embodiment described above can be obtained.
In the magnetic linear absolute encoder 1, stable magnetic field characteristics can be obtained even if the length of the position detection scale in the longitudinal direction (vertical direction in FIG. 5) is increased. Therefore, the magnetic linear absolute encoder 1 is more accurate than the first embodiment. High control is possible.
Further, the shapes of the first part and the second part are not limited to the present embodiment, and one of the first part and the second part gradually increases along the longitudinal direction of the position detection scale. However, it is possible to use an arbitrary shape in which the other is gradually reduced.

The magnetic linear absolute encoder of the present invention has been described based on the illustrated embodiment. However, the present invention is not limited to this, and the configuration of each part is of an arbitrary configuration having the same function. Can be substituted. In addition, any other component may be added to the present invention.
Further, the present invention may be a combination of any two or more configurations (features) of the above embodiments.

In the above embodiment, the magnetic sensor 11 is provided on the base 21 and the position detection scale 12 is provided on the slider 23. However, the present invention is not limited thereto. For example, the magnetic sensor 11 is provided on the slider and the position detection scale 12 is provided. May be provided on the base 21.
The application of the magnetic linear absolute encoder of the present invention is not particularly limited, and examples thereof include an ultrasonic linear actuator and a shape memory actuator.

1 is a plan view showing a first embodiment of a magnetic linear absolute encoder of the present invention. It is a figure for demonstrating a magnetic sensor. It is a top view which shows the structural example of the measurement system using the magnetic-type linear absolute encoder of this invention. It is a flowchart which shows the process of the measurement system using the magnetic type linear absolute encoder of this invention. It is a top view which shows 2nd Embodiment of the magnetic-type linear absolute encoder of this invention. It is a figure which shows the conventional magnetic type linear absolute encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Magnetic type linear absolute encoder, 2 ... Linear actuator, 11 ... Magnetic sensor, 12 ... Scale for position detection, 13 ... N pole part, 14 ... S pole part, 21 ... Base, 22 ... Base, 23 ... Slider, 231 ... Rack gear, 232 ... Projection, 26 ... Projection, 27 ... Bolt, 28 ... Arm , 29, rollers, 31, spring retaining pins, 32, spring hooks, 33, coil springs, 41, rotors, 42, cylindrical members, 43, driven bodies. 44 ... pinion gear, 6 ... vibrating body, 70 ... data control unit, 71 ... amplifier, 72 ... A / D converter, 73 ... CPU, 50 ... measurement System, 112, sensor unit, 100, rotating shaft, 200, drum, 00 ... Magnetic recording medium, 400 ... Substrate, 500 ... MR element, 600 ... Conductor terminal, 700 ... Lead wire, 800 ... Drive detection circuit, n1-n5 ... Magnetization Pattern sequence, S101-S107 ... step

Claims (11)

A magnetized long position detecting scale;
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor,
The magnetic linear absolute encoder is characterized in that the position detecting scale is configured such that the strength of the magnetic field gradually decreases or increases along the longitudinal direction thereof. A magnetized long position detecting scale;
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor,
The position detection scale is configured so that the strength of the magnetic field gradually decreases along the longitudinal direction thereof, the direction of the magnetic field is reversed in the middle, and the strength of the magnetic field is gradually increased. Absolute encoder. A magnetized long position detecting scale;
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor and a calibration curve indicating a relationship between the detection result and the absolute value of the position detection target. And
The magnetic linear absolute encoder is characterized in that the position detecting scale is configured such that the strength of the magnetic field gradually decreases or increases along the longitudinal direction thereof. A magnetized long position detecting scale;
A magnetic sensor that detects and magnetically converts a magnetic field generated from the position detection scale;
A magnetic linear absolute encoder comprising position detection means for obtaining an absolute position of a position detection target based on a detection result of the magnetic sensor and a calibration curve indicating a relationship between the detection result and the absolute value of the position detection target. And
The position detection scale is configured so that the strength of the magnetic field gradually decreases along the longitudinal direction thereof, the direction of the magnetic field is reversed in the middle, and the strength of the magnetic field is gradually increased. Absolute encoder.   5. The magnetic linear absolute encoder according to claim 3, wherein the calibration curve is set in advance.   6. The magnetism according to claim 3, further comprising magnetic field detection means for detecting a magnetic field in the vicinity of the magnetic sensor, wherein the calibration curve is corrected based on a detection result of the magnetic field detection means. Type linear absolute encoder.   The magnetic linear device according to claim 3, further comprising a temperature detection unit that detects a temperature of the magnetic sensor, and configured to correct the calibration curve based on a detection result of the temperature detection unit. Absolute encoder.   5. The magnetic linear absolute encoder according to claim 2, wherein the direction of the magnetic field is reversed at substantially the center in the longitudinal direction of the position detection scale.   9. The magnetic linear absolute encoder according to claim 1, wherein the position detection scale is magnetized in two poles so that one end side is an N pole and the other end side is an S pole in the longitudinal direction.   The position detection scale has a first part that is an N pole and a second part that is an S pole, and the ratio of the area of the first part to the area of the second part is the position detection. 9. The magnetic linear absolute encoder according to claim 1, wherein the magnetic linear absolute encoder is gradually increased or gradually decreased along the longitudinal direction of the working scale. The length of the first portion in a direction substantially perpendicular to the longitudinal direction of the position detection scale gradually increases along the position detection scale and is substantially perpendicular to the longitudinal direction of the position detection scale. The magnetic linear absolute encoder according to claim 10, wherein the length of the second portion in a specific direction gradually decreases along the position detection scale.

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