JP4593216B2 - Torque motor used for positioner - Google Patents

Description

  The present invention relates to a torque motor used for a positioner, and more particularly to a torque motor used for a positioner that does not cause a malfunction even when an iron material or the like is approached.

  Conventionally, a positioner has been used for valve drive control, process automation, and drive control of other general industrial equipment. By attaching this positioner to a regulating valve, the drive control of the valve is made possible.

  By the way, as is well known, a positioner generally controls a drive unit for driving a regulating valve, a pilot valve for driving the drive unit by supplying air to the drive unit, and an operation of the pilot valve. In the electropneumatic positioner that operates the pilot valve using an electric signal, the operation of the pilot valve is controlled using a torque motor.

  This relationship will be described with reference to FIG. 4. FIG. 4 is a view for explaining the structure of a torque motor 2 used in a general electropneumatic positioner, and FIG. 5 is a view of the torque motor 2 shown in FIG. 4 is a view showing the above from the lower side in FIG. 4. The conventional torque motor 2 includes a nozzle 9 connected to a nozzle back pressure chamber in a pilot valve by an air pipe 10, and a flapper 8 is connected to the nozzle 9. The nozzle 9 is provided in an arrangement capable of closing the opening. The flapper 8 is attached to an armature 6 supported by a fulcrum spring 7, and by moving the armature 6, the flapper 8 is moved in a direction to release the opening of the nozzle 9. Therefore, it is possible to operate the pilot valve by discharging air from the nozzle 9.

  The electropneumatic positioner generally employs a system in which the armature 6 is moved using a coil 4. That is, in FIG. 4, 4 is a coil, and an armature 6 passes through the coil 4. A magnetic field is generated by applying a signal current to the coil 4, and the armature 6 is moved by the magnetic force. It is possible.

  In the figure, reference numeral 5 denotes a yoke. In the electropneumatic positioner, the magnetic force generated in the coil 4 is used as a circuit for more effectively using the magnetic force generated by applying the signal current to the coil 4. A pair of yokes 5 are arranged in the same direction as the above.

  Further, the positioner generally has a magnet 14 attached to the yoke as auxiliary power for the yoke 5. That is, since the positioner is attached to the regulator valve and operates, the positioner is susceptible to a great deal of vibration during fluid control of the regulator valve, and therefore must be robust. Therefore, since it is necessary to use a torque motor having a large torque, it is common to use the magnet 14 as auxiliary power.

  That is, in the conventional positioner, the armature is sandwiched between the tip portions of the pair of yokes 5, and the magnet 14 having a substantially U shape is arranged so as to be positioned between the pair of yokes 5. It was set up.

  At this time, the magnetism of the magnet is inversely proportional to the square of the distance, and the magnetic force is considerably attenuated at the tip of the yoke 5, so that a considerably large magnet is required. Therefore, the conventional positioner uses a large magnet. Therefore, the torque motor was enlarged. In addition, the use of a magnet having a strong magnetic force, such as a rare earth magnet, can prevent an increase in the size of the torque motor. Since it was difficult to capture, a considerable amount of magnetism leaked to the surroundings, and when the iron material was brought close to the torque motor, it drifted greatly.

  Therefore, in order to cope with this problem, conventionally, the case and cover for storing the torque motor were enlarged to provide a distance between the torque motor and a magnetic shield. If it is enlarged, there is a problem that the entire device becomes large, and since the magnetic shield is a structure covered with an iron plate etc., the magnetic force of the original torque motor is absorbed at a position close to the magnet, As a result, torque shortage occurs, so a larger magnet has to be added, which is not effective.

  Also, when performing zero point adjustment or span adjustment with the positioner, the cover is removed, but at this time, the zero and span are greatly affected by the tool used for adjustment. It was difficult to adjust because ordinary users often do not have special tools.

  As described above, in the conventional electro-pneumatic positioner, the magnetism used in the torque motor and the influence of the iron material have caused drift that contributes to malfunction, but an effective method for solving this problem has been proposed. It wasn't.

  Therefore, an object of the present invention is to provide a torque motor for a positioner capable of preventing drift due to the influence of magnetism and iron material of a magnet used for the torque motor.

The torque motor used in the positioner of the present invention is
A nozzle communicating with the pilot valve, a flapper movable in a direction to close or release the opening of the nozzle, an armature for moving the flapper, a coil through which the armature is movably penetrated, and A substantially U-shaped yoke mounted in such a manner that a pair of legs sandwich the vicinity of the tip of the armature at the tip of the coil opposite to the fulcrum position of the armature, and an end surface of the yoke NS / NS rare earth magnets mounted in series, the direction of the magnetic lines of force of the magnet and the direction of movement of the armature are the same direction, and the magnetic lines of force of the magnet and the magnetic lines of the coil are perpendicular to each other. By doing so, the magnetism of the magnet is changed to yoke, magnet, armature, magnet. , And so as to form a closed circuit in the order of the yoke,
The cross-sectional area of the magnet in the magnetic field line direction in the yoke is made larger than the area of the end surface in contact with the yoke in the magnet, and the width of the leg is made larger than the thickness of the magnet,
Further, a side plate capable of guiding the magnetic field lines of the coil is disposed on the outer peripheral side of the leg portion so that the magnetic field lines of the coil and the magnetic field lines of the magnet can be merged in the vicinity of the tip of the armature. The magnet side tip is substantially L-shaped so as to be positioned substantially perpendicular to the fulcrum of the armature, and is arranged close to the armature, thereby generating a current signal applied to the coil It is characterized in that two magnetic circuits differing by 90 degrees can be coaxially merged at the armature portion so as to form a closed circuit in the order of armature, magnet, and side plate .

  In order to solve the above problem, it is desirable to adopt a structure that does not leak the magnetic force lines of the torque motor to the outside, and it is desirable to use a strong magnetic rare earth magnet for the torque motor.

  In this regard, according to the present invention, a rare earth magnet is disposed at a position very close to both sides of the armature, and this magnet sandwiches the vicinity of the tip on the opposite side of the armature fulcrum position. Can be reduced to a fraction of that of the conventional method, and an ultra-small electro-pneumatic positioner can be manufactured. As a result, the burden on the regulating valve can be reduced, and the vibration resistance can be greatly improved.

  According to the present invention, the magnetism of the magnet after acting on the armature passes along the U-shaped yoke, so that (1) yoke, (2) magnet, (3) armature, (4) magnet, (5) The yoke and magnetism constitute a closed circuit, and the magnetism can be effectively prevented from leaking to the periphery, thereby enabling the magnetism of the magnet to be taken out efficiently.

  Therefore, according to the present invention, no special tool can be required at the time of zero point adjustment or span adjustment. That is, according to the present invention, even when a large iron material such as a hammer or a large monkey spanner that was not considered in conventional models is approached, there is almost no malfunction. There is no need to use special tools made of magnetic materials, and adjustments can be made even by ordinary users.

  The torque motor used in the positioner of the present invention includes a nozzle communicating with the pilot valve, a flapper movable in a direction to close or release the opening of the nozzle, and an armature for moving the flapper. Yes. Further, the armature includes a coil that is movably penetrated, and the front end portion of the coil opposite to the fulcrum position of the armature is disposed so as to sandwich the vicinity of the front end portion of the armature and has a pair of legs. A U-shaped yoke is disposed. A rare earth magnet is mounted on the end face of the yoke so that NS and NS are in series, so that the direction of the magnetic lines of force of the magnet and the operating direction of the armature are the same.

  Here, in the yoke, the cross-sectional area of the magnet in the direction of the line of magnetic force is made larger than the area of the end face of the magnet in contact with the yoke, the width of the leg is made larger than the thickness of the magnet, The side plate may be disposed on the outer peripheral side of the leg portion in such an arrangement that the magnetic field lines of the coil and the magnetic field lines of the magnet can be merged in the vicinity of the tip of the armature. The tip end portion on the side opposite to the magnet may be substantially L-shaped so as to be positioned substantially perpendicular to the fulcrum portion of the armature, and may be disposed close to the armature.

  And according to this, since the magnetism generated by the current signal applied to the coil passes through the armature and merges with the magnetism of the magnet and passes through the L-shaped side plate disposed on the side surface of the yoke, the magnetism is also closed here. And so that two so-called 90 degrees different magnetic circuits are coaxially joined at the armature portion, so that the magnetism of the magnet can be taken out more efficiently.

  Further, the bias is applied so that the tip of the armature is sandwiched between a pair of bias springs arranged in a direction perpendicular to the longitudinal direction of the armature and the operation of the armature is controlled in a direction parallel to the longitudinal direction of the armature. A spring may be provided, which makes it possible to easily adjust the position of the armature.

  At this time, the bias spring for urging the distal end of the armature may be made of a non-magnetic material or a material that is difficult to be magnetized, thereby preventing malfunction.

  An embodiment of the torque motor used in the positioner of the present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining the torque motor of the present embodiment, in which 2 is the torque motor. FIG. 2 is a partially omitted perspective view for explaining the basic structure of the torque motor 2 in this embodiment.

  And in the torque motor 2 of a present Example, it has the coil 4 accommodated in case 3, The armature 6 is arrange | positioned by the arrangement | positioning which penetrates this coil 4, and the upper end part vicinity of this armature 6 is the following. The mounting member 12 supports the fulcrum spring 7 mounted on the case 3, and further, the upper end portion of the armature 6 is mounted on the case 3 by the mounting member 12 and communicates with the pilot valve via the air pipe 10. A flapper 8 capable of closing the opening of the nozzle 9 and releasing the closing is mounted.

  Next, a substantially U-shaped yoke 5 is provided at a tip of the coil 4 opposite to the fulcrum position of the armature 6, and a pair of legs 501 has a tip of the armature 6 opposite to the fulcrum position. It is installed in such a way that it is sandwiched. That is, each of the pair of leg portions 501 has its tip end directed toward the armature 6, whereby the pair of leg portions 501 have their end surfaces opposite to the tip end on the opposite side of the fulcrum position in the armature 6. The arrangement is such that it is sandwiched.

  Further, the rare earth magnets 14 are mounted on the end surfaces of the pair of leg portions 501 so as to be in NS / NS series in such an arrangement that the opposite end portions of the armature 6 to the fulcrum positions are sandwiched. Thus, the magnetic lines of force of the magnet 14 and the lines of magnetic force of the coil 4 are perpendicular to each other.

  For this purpose, the magnet 14 forms a closed circuit in the order of (1) yoke 5, (2) magnet 14, (3) armature 6, (4) magnet 14, and (5) yoke 5. Can be prevented from leaking to the periphery.

Next, in this embodiment, the cross-sectional area of the yoke 5 when viewed in the direction of the magnetic force of the magnet 14 is configured to be larger than the area of the end surface of the magnet 14 that contacts the yoke 5, and the leg 501 The dimension in the direction perpendicular to the longitudinal direction of the armature 6 is made larger than the thickness dimension of the magnet 14. Further, on the outer peripheral side of the coil 4, the magnetic field lines of the coil 4 and the magnetic field lines of the magnet 14 However, a side plate 15 capable of inducing magnetic field lines is arranged in such a manner that it can be merged in the vicinity of the tip of the armature 6.

  Further, the side plate 15 has the opposite end on the side opposite to the magnet facing the armature 6, thereby making the side plate 15 substantially L-shaped and arranged close to the armature 6. . Therefore, the magnetism generated by the current signal applied to the coil 4 passes through the armature 6 and merges with the magnetism of the magnet 14 and passes through the L-shaped side plate 15 disposed on the side surface of the yoke 5. Thus, two so-called 90 degrees different magnetic circuits can be coaxially joined at the armature 6 portion, and the magnetism of the magnet can be taken out more efficiently.

  As described above, in the torque motor 3 of this embodiment, since a strong magnetism rare earth magnet is used, it is not necessary to enlarge the magnet, and the torque motor can be reduced in size, thereby further reducing the size of the entire positioner. It became possible to do.

  Further, a substantially U-shaped yoke 5 is mounted on the coil 4 at the tip of the armature 6 opposite to the fulcrum position of the armature 6 so as to sandwich the lower end of the armature 6. Since the rare earth magnet 14 is mounted in the NS / NS series in this part, the magnetic lines of force of the magnet 14 and the magnetic lines of the coil 4 are perpendicular to each other. Therefore, the yoke 4, the armature 6 and the magnet 14 can form a magnetic closed circuit, and the magnetism of the magnet does not leak to the periphery.

  Further, a side plate 15 is arranged around the coil 4 so as to be coaxial with the magnetic field lines of the magnet 14, and the side plate 15 is made substantially perpendicular to the armature 6 with the tip on the side opposite to the magnet. Therefore, the magnetism generated by the current signal applied to the coil 4 passes through the armature 6 and merges with the magnetism of the magnet 14 and passes through the L-shaped side plate 15 disposed on the side surface of the yoke 5. For this reason, a magnetic closed circuit is formed here, so that two magnetic circuits different from each other by 90 degrees can be coaxially joined at the armature 6, so that the magnetism of the magnet can be taken out more efficiently. It was.

  Therefore, according to the present invention, even when a large iron material, such as a hammer or a large monkey spanner, which has not been considered in conventional models is approached, there is almost no malfunction, and a non-magnetic material is used during zero point adjustment and span adjustment. It is not necessary to use special tools and adjustments can be made by ordinary users.

  Next, in FIGS. 1 and 2, 16 is a bias spring, that is, in this embodiment, a pair of locking portions 18 are mounted on the outer peripheral surface of the yoke 5 and the pair of locking portions 18 are interposed. A bias spring 16 is disposed on the side.

  This structure will be described in detail. In the present embodiment, the bias springs 16 are fixed to both end sides of the locking bracket 1903 to which the tip of the armature 6 is locked, and the ends of the pair of bias springs 16 are fixed. A metal fitting 1902 is also fixed to the portion. Then, the metal fittings 1902 are pressed by screws 1901 penetrating the locking portions 18, whereby the bias spring 16 is disposed between the locking portions 18, and the tip of the armature 6 is moved by the bias spring 16. It is energized from both sides. This prevents the armature 6 from being attracted to the magnet 14 when no input signal is applied.

  Here, the bias spring 16 will be described. In the present embodiment, the bias spring 16 that biases the tip of the armature 6 from both sides is made of a non-magnetic material or a material that is difficult to magnetize. This prevents the bias spring 16 from being magnetized. That is, when the bias spring 16 that biases the tip of the armature 6 is made of a magnetic material, the bias spring is magnetized by the influence of the magnet 14 and the like, and the magnetic force affects the closed circuit. It can be considered that the zero point is mad. Therefore, in the present embodiment, the bias spring 16 that urges the tip of the armature 6 from both sides is made of a non-magnetic material or a material that is difficult to be magnetized, thereby effectively preventing the zero point from going wrong. It is possible. In this embodiment, stainless steel 316 is used as a specific material of the bias spring 16 as a material that is not easily magnetized. However, it is not always necessary to use a non-magnetic material or the like, and a magnetic material may be used when it is possible to solve the fact that the zero point is off by other methods.

  Next, in this embodiment, a bias spring 17 is also connected between the side plate 15 and the flapper 8 in a direction parallel to the longitudinal direction of the armature, and the bias spring 17 is connected to the armature 6. Similar to the bias spring 16 disposed in the vicinity of the tip of the armature, it is used for armature position control.

  In this embodiment, a non-magnetic stopper 13 is mounted between the magnet 14 and the armature 6, so that the armature 6 is attracted to the magnet 14 when no input signal is applied. Is preventing.

  Next, the positioner using the torque motor 3 of the present embodiment configured as described above will be briefly described. FIG. 3 is a diagram for explaining the electropneumatic single-acting positioner. In FIG. A position indicated by a chain line is the positioner 1.

  In use, the positioner 1 is communicated with the drive unit 51 by the conducting pipe 71, thereby enabling control of the valve connected to the driving unit 51, and the drive unit 51 is connected via the conducting pipe 71. A pilot valve 21 for driving the drive unit 51, a torque motor 2 for controlling the operation of the pilot valve 21, and a drive control means for controlling the drive of the drive unit 51. 41.

  Here, first, the drive unit 51 will be described. The drive unit 51 includes a movable wall 53, and a drive unit pressure chamber 52 is formed in an arrangement partitioned by the movable wall 53. 52 is connected to the conducting pipe 71. In addition, a stem 54 is connected to the counter driving portion pressure chamber side of the movable wall 53, and a valve is connected to a tip portion of the stem 54. With this configuration, when air is supplied into the drive unit pressure chamber 52 through the conducting pipe 71, the movable wall 53 expands toward the stem 54, and the stem 54 moves toward the connected valve side. Thus, the valve can be driven. In the figure, reference numeral 55 denotes a spring for controlling the expansion of the movable wall 52, and a feedback bag is added to the expansion of the movable wall 53 by the spring 55.

  Next, in FIG. 3, reference numeral 21 denotes a pilot valve 21, which is constituted by a primary pressure chamber 22 a having an air supply port 2201 and a secondary pressure chamber 22 b communicated with the primary pressure chamber 22 a. The supply air pressure chamber 22 is provided, and the secondary side pressure chamber 22b is provided with an output port 2202 that communicates with the drive unit pressure chamber 52 via a conduction pipe 71.

  An air supply valve seat 23 is formed between the primary side pressure chamber 22a and the secondary side pressure chamber 22b, and a space formed by the air supply valve seat 23 serves as an air supply passage.

  Further, one end portion of an exhaust valve seat 29 is movably inserted into the secondary side pressure chamber 22b, and the exhaust valve seat 29 is opened in the secondary side pressure chamber 22b and at any location. Thus, an exhaust passage 2901 is formed in which an exhaust port 2902 communicating with the outside is formed.

  Further, a valve body 24 having a supply valve 2401 and an exhaust valve 2402 concentrically integrated in the supply pressure chamber 22 is provided by the supply valve 2401, the supply passage, and the exhaust valve 2402. It is inserted by a spring so that the opening of the exhaust passage 2901 can be closed.

  Next, a nozzle back pressure chamber 26 is formed in the pilot valve 2, and one end of the nozzle back pressure chamber 26 communicates with the primary pressure chamber 22a.

  A pressure chamber 27 is formed in the pilot valve 21, and an air supply pipe 72 is connected to the pressure chamber 27. The nozzle back pressure chamber 26 and the pressure chamber 27 are partitioned by a partition wall such as a diaphragm 28, and a partition wall such as a diaphragm is also provided on the side of the pressure chamber 27 facing the nozzle back pressure chamber 26. The valve seat 29 is movably provided in a form supported by the diaphragm 28.

  Next, in FIG. 3, reference numeral 2 denotes the torque motor shown in FIG. 1, and this torque motor 2 is used to operate the exhaust valve seat 29 in the pilot valve 21. That is, when a signal current is applied to the coil 4, the armature 6 moves around the fulcrum spring 7 in the direction in which the flapper 8 releases the blockage of the tip of the nozzle 9, in the direction of arrow A in the figure. Then, the flapper 8 is pulled away from the tip of the nozzle 9 by the movement of the armature 6, thereby releasing air from the nozzle 9 and reducing the pressure in the nozzle back pressure chamber 26, and the nozzle back pressure chamber 26 and the pressure chamber 27. The air pressure balance is lost.

  Then, the diaphragm 28 partitioning the nozzle back pressure chamber 26 and the pressure chamber 27 moves to the nozzle back pressure chamber 26 side, and the exhaust valve seat 29 supported by the diaphragm 28 is connected to the supply pressure chamber 22a side. Move to.

  As a result, the exhaust valve seat 29 pushes up the valve body 23. Accordingly, in the pressure chamber 22, the supply valve seat 23 is opened and the exhaust passage 2901 of the exhaust valve seat 29 is closed, and the output port Air is supplied into the drive unit pressure chamber 52 through 2202 and the conducting pipe 71, whereby the partition wall 53 expands toward the stem side to move the stem 34, and drives the regulating valve connected to the stem. It becomes possible.

  In FIG. 3, reference numeral 41 denotes a drive control means for adding a feedback to the drive of the stem 54. The drive control means 41 includes feedback levers 42 and 43 connected to arbitrary portions of the stem 54. The feedback levers 42 and 43 are connected to a cam 44 so that the cam 44 rotates when the stem 42 moves. Further, the tip end portion of the range adjustment arm 45 is in contact with the cam 44, and when the cam 44 rotates, the range adjustment arm 45 rotates counterclockwise around the fulcrum. Further, a bearing shaft 46 is connected to the range adjusting arm 45, and a zero adjusting arm 47 is brought into contact with the bearing shaft 46, and the range adjusting arm 45 rotates counterclockwise as the cam 44 rotates. Then, the zero adjustment arm 47 rotates clockwise around the fulcrum while sliding on the bearing shaft 46. Then, one end of a feedback spring 48 having the other end connected to the flapper arm 11 in the operation control unit 2 is connected to the tip end portion (the side opposite to the fulcrum) of the zero adjustment arm 47, and as the cam 44 rotates. As the zero adjustment arm 47 rotates clockwise, the feedback spring 48 is pulled upward, and the flapper 8 is returned in a direction to close the tip of the nozzle 9.

  In such a configuration, as the stem 54 moves, the cam 44 rotates in the clockwise direction (arrow C direction) via the feedback levers 42 and 43, and the rotation of the cam 44 causes the range adjustment arm to rotate. 45 rotates counterclockwise (arrow D direction) around the fulcrum.

  Then, when the range adjustment arm 45 rotates counterclockwise, the zero adjustment arm 47 supported by the bearing shaft 46 rotates clockwise about the fulcrum (in the direction of arrow E), thereby the feedback spring. 48 is pulled up (in the direction of arrow F), the flapper arm 11 is pulled up, and when the tension of the feedback spring 48 and the suction force of the coil 4 are balanced, the flapper 8 closes the tip of the nozzle 9. Approaching.

  Then, the air discharged from the nozzle 9 decreases and the pressure in the nozzle back pressure chamber 26 increases, and the balance of the air pressure in the nozzle back pressure chamber 26 and the pressure chamber 27 approaches the initial state. The diaphragm 28 partitioning the chamber 26 and the pressure chamber 27 moves toward the pressure chamber 27, and the exhaust valve seat 29 supported by the diaphragm 28 approaches the initial position. As a result, the supply valve 2401 moves in the direction of closing the supply valve seat 23 in the supply pressure chamber 22a.

  As a result, the amount of air supplied to the drive unit pressure chamber 52 decreases and the movement of the stem 54 stops. That is, the stem 54 moves until the tension of the feedback spring 48 and the attractive force of the coil 4 are balanced, thereby obtaining a change in the stem 54 proportional to the input signal current.

  The torque motor used in the positioner of the present invention is not limited to the single-acting type positioner described above, and can be applied to all electropneumatic positioners. This makes it possible to reduce the size of the positioner and adjust the zero point. A special tool is not required for span adjustment, and the user can make adjustments.

It is a figure for demonstrating the Example of the torque motor of this invention. It is the perspective view which showed the basic structure of the Example of the torque motor of this invention. It is a figure for demonstrating the single action type electropneumatic positioner using the Example of the torque motor of this invention. It is a figure for demonstrating the conventional torque motor. It is a figure for demonstrating the conventional torque motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positioner 2 Operation control part 3 Torque motor 4 Coil 5 U-shaped yoke 501 A pair of leg part 6 Armature 7 A fulcrum spring 8 Flapper 9 Nozzle 10 Air pipe 11 Flapper arm 12 Mounting member 13 Stopper 14 Magnet 15 Side plate 16, 17 Bias spring 18 Locking portion 1901 Screw 1902 Metal fitting 1903 Locking metal fitting 21 Pilot valve 22 Supply air pressure chamber 22a Primary side pressure chamber 22b Secondary side pressure chamber 2201 Supply port 2202 Output port 23 Supply valve seat 24 Valve body 2401 Supply air Valve 2402 Exhaust valve 26 Nozzle back pressure chamber 27 Pressure chamber 28 Diaphragm 29 Exhaust valve seat 2901 Exhaust passage 2902 Exhaust port 41 Drive control unit 42, 43 Feedback lever 44 Cam 45 Range adjustment arm 46 Bearing shaft 47 Zero adjustment arm 48 Feedback Spring 51 driving unit 52 drive unit the pressure chamber 53 partition wall 54 stem 55 spring

Claims (3)

A torque motor for operating a pilot valve in a positioner,
A nozzle (9) communicating with the pilot valve;
A flapper (8) movable in a direction to close or release the opening of the nozzle (9);
An armature (6) for moving the flapper (8);
A coil (4) through which the armature (6) movably passes;
In the coil (4), the armature (6) is mounted at an end on the side opposite to the fulcrum position of the armature (6) so that a pair of legs (501) sandwiches the vicinity of the end of the armature (6). A U-shaped yoke (5);
A rare earth magnet (14) mounted on the end face of the yoke (5) so that NS and NS are in series;
By making the direction of the magnetic force line of the magnet (14) and the operating direction of the armature (6) the same direction, the magnetic force line of the magnet (14) and the magnetic force line of the coil (4) are perpendicular to each other. The magnet (14) forms a closed circuit in the order of the yoke (5), the magnet (14), the armature (6), the magnet (14), and the yoke (5);
The cross-sectional area of the magnet (14) in the magnetic field direction of the yoke (5) is larger than the area of the end surface of the magnet (14) contacting the yoke (5), and the width of the leg (501). The dimension is larger than the thickness of the magnet (14),
Further, the magnetic field lines of the coil (4) and the magnetic field lines of the coil (4) are arranged on the outer peripheral side of the leg part (501) in such an arrangement that the magnetic field lines of the coil (4) and the magnetic field lines of the magnet (14) can be merged near the tip of the armature (6). A side plate (15) capable of guiding the armature (15) is disposed, and the tip end portion on the side opposite to the magnet of the side plate (15) is substantially L-shaped so as to be positioned substantially perpendicular to the fulcrum portion of the armature (6). And the magnetism generated by the current signal applied to the coil (4) is arranged in the order of the armature (6), the magnet (14), and the side plate (15). A torque motor for a positioner, characterized in that a closed circuit is formed so that two magnetic circuits different by 90 degrees can be coaxially joined at the armature (6) .   The armature (6) is urged so as to be sandwiched between a pair of bias springs (16) arranged in a direction perpendicular to the longitudinal direction of the armature (6) and parallel to the longitudinal direction of the armature (6). The torque motor of the positioner according to claim 1, further comprising a bias spring (17) for controlling the operation of the armature (6).   The torque motor for a positioner according to claim 2, wherein the bias spring (16) biasing the tip of the armature (6) is made of a non-magnetic material or a material that is difficult to magnetize.

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