JP2000032731A - Torque motor and fluid pressure controller therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque motor and a fluid pressure controller, capable of attaining size reduction, sufficient torque characteristics, and easy assembly. SOLUTION: This torque motor 12 includes a yoke 24 having lower yokes 18, 20 and an upper yoke 22, permanent magnets 26, 28 formed out of a rare- earth magnet, a coil 32 wound around the center foot 30a of the upper yoke 22, and an armature 34 to which a flapper 36 is connected. The permanent magnets 26, 28 are formed so as to be sandwiched by the lower yoke 18, 20 respectively at an even distance to the right and left from the center of the yoke 24 and to diagonally cross magnetic flux generated in the yoke 24. When the torque motor 12 is mounted on an electricity-to-pressure converting part 14, the armature 34 is disposed and a desired gap is formed in a space to the armature 34 to mount the respective parts of the yoke 24 and the permanent magnets 26, 28.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque motor and a fluid pressure control device using the torque motor, and more particularly to a torque motor and a fluid pressure control device using the torque motor which are applied to, for example, a nozzle flapper type electrohydraulic servo valve. It relates to a control device.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a conventional nozzle flapper type electrohydraulic servo valve which performs hydraulic control using a magnet.

A conventional electrohydraulic servo valve 1 shown in FIG.
Is a torque motor 2 for controlling the position of the flapper 2d,
An electric-pressure converter 3 for operating the spool 4b in accordance with the position of the flapper 2d, and a spool 4b for controlling the outflow direction and flow rate of oil from a pump (not shown).
And a valve element 4 having

The torque motor 2 includes an upper magnetic pole 2a and a lower magnetic pole 2b fixed so as to sandwich a pair of permanent magnets (not shown), an armature 2c disposed in the middle of a gap between the upper magnetic pole 2a and the lower magnetic pole 2b. It includes a flapper 2d for supporting the armature 2c, a pair of coils 2e and 2f wound around the armature 2c, and a feedback spring 2g for generating a torque for returning the flapper 2d to a neutral position. When the coils 2e and 2f are energized, the armature 2c becomes an electromagnet. Further, the flapper 2d itself has elasticity and is fixed around the fulcrum A1, and maintains the armature 2c in an equilibrium state in a state where the coils 2e and 2f are not energized.

The electric-to-pressure converter 3 includes a pair of nozzles 3a and 3b installed on the left and right of the flapper 2d, and displaces the spool 4b by the back pressure of the nozzles 3a and 3b.

The valve body 4 includes a cylinder 4a in which oil moves,
Spool 4b that controls oil pressure by sliding in cylinder 4a
And supply ports 4c1 and 4c2 for supplying oil from a pump to an actuator (both not shown).
And control ports 4d1 and 4d2 for supplying oil to the actuator and returning oil from the actuator to a tank (not shown), and return ports 4e1 and 4e2 for returning oil to the tank.

In the electro-hydraulic servo valve 1 thus configured, the torque motor 2 includes the coils 2e and 2e.
The armature 2c is in an equilibrium state when no current is applied to f.

When the coils 2e and 2f are energized, a magnetic field is generated and the armature 2c is given a magnetic polarity. The armature 2c loses the equilibrium state due to the torque generated according to the magnitude and polarity of the current, and tilts in any direction. With the tilt of the armature 2c, the flapper 2d fixed to the armature 2c also tilts,
The distance between the nozzles 3a and 3b and the flapper 2d is changed. According to this displacement, the back pressure of each of the pair of nozzles 3a and 3b changes. The back pressure of each of the nozzles 3a and 3b is guided to both ends of the spool 4b, and the spool 4b is displaced by a change in the back pressure.

The displacement of the spool 4b causes the feedback spring 2g connected to the flapper 2d to generate a torque opposite to the magnetic torque of the armature 2c, and pulls the flapper 2d back to the neutral position. When the flapper 2d returns to the neutral position, the back pressures of the nozzles 3a and 3b become equal, and the spool 4b stops at that position.

As described above, the direction and amount of oil flow are controlled according to the magnitude and polarity of the input current.

[0011]

However, in the conventional electrohydraulic servo valve 1 as described above, in order to obtain sufficient torque characteristics, it is necessary to enlarge the upper magnetic pole 2a, the lower magnetic pole 2b, and the armature 2c. Yes, contrary to the demand for miniaturization.

Further, a fine adjustment operation is required to mount the armature 2c in the middle of the gap between the upper yoke 2a and the lower yoke 2b so that the armature 2c is in an equilibrium state. Was.

SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a small-sized, sufficient torque characteristic and easy assembly.
An object of the present invention is to provide a torque motor and a fluid pressure control device using the torque motor.

According to a first aspect of the present invention, there is provided a torque motor, comprising: a yoke, a coil wound around the yoke, and a yoke at a central portion of the yoke. And two rare-earth magnets formed so as to be sandwiched between the yoke at positions opposite and equidistant from the center of the yoke, respectively. According to a second aspect of the present invention, in the torque motor of the first aspect, the rare-earth magnet is formed so as to be oblique to a direction of a magnetic flux generated in the yoke.

According to a third aspect of the present invention, there is provided a fluid pressure control apparatus using the torque motor according to the first or second aspect.

In the torque motor according to the first aspect, since the rare earth magnet is used as the permanent magnet, the magnetic flux density can be increased. Therefore, unlike the related art, a sufficient torque can be obtained without increasing the size of the upper magnet, the lower magnet, and the armature, even if the size is small.

According to the second aspect of the present invention, the surface area of the rare-earth magnet can be increased by forming the rare-earth magnet so as to be oblique to the direction of the magnetic flux generated in the yoke. Since the magnetic flux density in the yoke can be further increased, a larger torque can be obtained.

When the fluid pressure control device is constructed using the torque motor according to claim 1 or 2, an armature is first arranged, and a predetermined gap is formed with the armature to form a rare earth magnet which is a yoke and a permanent magnet. And are attached. As described above, since the yoke and the rare earth magnet are attached after the armature is arranged, a desired gap can be easily provided between the armature and the yoke, and unlike the conventional case, the armature is set in an equilibrium state. There is no need for detailed adjustment work.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the present invention is applied to a nozzle flapper type electro-hydraulic servo valve used for hydraulic control will be described below with reference to the drawings.

Referring to FIGS. 1 to 3, an electrohydraulic servo valve 10 according to an embodiment of the present invention
2, an electric-pressure converter 14 and a valve body 16.

The torque motor 12 is configured as a single air gap type torque motor,
And a yoke 24 having an upper yoke 22 having an E-shaped cross section,
Plate-like permanent magnets 26 and 28 made of rare earth magnets sandwiched between lower yoke 18 and 20, respectively, and upper yoke 2
2, a coil 32 wound around the center leg 30a, an armature 34 formed of, for example, permalloy and arranged on an extension of the center leg 30a and between the lower yoke 18 and 20, and a flapper connected to the armature 34 3
6 and a feedback spring 38 having one end fixed to the lower end of the flapper 36 and the other end fixed to the center of a spool 62 (described later) of the valve body 16 and generating a torque for returning the flapper 36 to the neutral position. As the permanent magnets 26 and 28, for example, a neodymium magnet, a samarium cobalt magnet, or the like is used. The flapper 36 is formed of, for example, a beryllium copper alloy, has elasticity by itself, and is fixed to the fulcrum A2.

The lower yoke 18 and the lower yoke 20 are respectively divided into two parts obliquely in front view at a position equidistant from the center of the yoke 24 in the left and right directions, and a second part (left magnetic pole) 42a. , And a first portion 40b and a second portion (right magnetic pole) 42b, and the permanent magnet 26 is provided between the first portion 40a and the second portion 42a.
Each of the permanent magnets 28 is sandwiched between the portion 42b.
Therefore, the permanent magnets 26 and 28 are formed, for example, in a substantially C-shape so as to be oblique to the direction of the magnetic flux generated in the yoke 24 at the center of the yoke 24, that is, at a position equidistant from the armature 34 in the left and right directions. And the torque motor 12
Are configured symmetrically. The permanent magnets 26 and 28
If the angle θ (see FIGS. 4 and 5) is reduced, the surface area of the permanent magnets 26 and 28 can be increased, so that the magnetic flux density of the yoke 24 can be increased and the torque can be increased. Considering the ease of mounting and processing, it is desirable that the angle θ be close to 90 degrees. In this embodiment, the angle θ is set to about 40 degrees to optimize the above-described effects regarding the torque and the attachment of the components.

The electric-to-pressure converter 14 is mounted near the upper end of the nozzle block 44 and the flapper 36 to support the flapper 36 and to connect the torque motor 12 to the electric
A flexure tube 46 for sealing between the pressure converter 14; a pair of nozzles 48a and 48b housed in the nozzle block 44 and arranged on the left and right of the flapper 36 to form a variable orifice with the flapper 36; Oil from nozzles 48a and 48b
Supply ports 50a and 50b for supplying oil to the nozzles 48a and 48b, inlet orifices (fixed orifices) 52a and 52b for supplying oil through the supply ports 50a and 50b, respectively, and from the tips of the nozzles 48a and 48b. It includes a return port 54 for returning the discharged oil to a tank (not shown), and back pressure ports 56a and 56b for transmitting the back pressure of the nozzles 48a and 48b to both ends of the spool 62.

The valve body 16 includes a body 58, a sleeve (bushing) 60 formed in the body 58, a spool 62 that slides in the sleeve 60 to control hydraulic pressure, and end portions that are fitted to both ends of the body 58. Caps 64a and 64b and supply ports 66a and 66b for supplying oil from a pump to an actuator (not shown)
And control ports 68a and 68b for supplying oil to the actuator and returning oil from the actuator to the tank, and a return port 70 for returning oil discharged from the tips of the nozzles 48a and 48b to the tank.

The torque motor 12 configured as described above
Is attached to the electric-pressure converter 14, first,
The flapper 36 is inserted through the flexure tube 46 such that the armature 34 projects from the upper surface of the nozzle block 44 and the flapper 36 is located between the nozzles 48a and 48b.

Next, the first member 40a and the second member 42a
The lower yoke 18 is assembled with the permanent magnet 26 interposed therebetween, and the lower yoke 20 with the permanent magnet 28 interposed between the first member 40b and the second member 42b. At this time, between the first member 40a, the permanent magnet 26 and the second member 42a,
The first member 40b, the permanent magnet 28, and the second member 42b are bonded, for example, respectively.

Then, the second member 42a and the armature 3
4, the second member 42b and the armature 34
A predetermined dimension (for example, 0.3
The gaps G (see FIG. 2) are formed, and the lower yokes 18 and 20 are arranged on the upper surface of the nozzle block 44.

The upper yoke 24 is arranged on the upper surfaces of the lower yoke 18 and 20 thus arranged on the nozzle block 44. At this time, the upper yoke 24 is arranged so that the central yoke 30 a is located on an extension of the armature 34, and the upper yoke 24 is fixed to the lower yoke 1 by the bolt 72.
8, 20 and the nozzle block 44, and the mounting of the torque motor 12 is completed.

In such an electrohydraulic servo valve 10, in the torque motor 12, when the coil 32 is not energized, the magnetic flux B generated by the permanent magnets 26 and 28
(See FIGS. 4 and 5), the yoke 24 is magnetized and the armature 34 and the second portion 42a are magnetized.
Since the magnitude of the generated magnetic flux is equal between the armature 34 and the second portion 42b, the attractive force acting between the armature 34 and the second portion 42b is also equal. As a result, the armature 34 is not tilted to the left or right side and is in an equilibrium state. Is kept.

However, as shown in FIG. 4, when the coil 32 is energized so as to generate the magnetic flux C1, the magnetic flux C1 by the coil 32 and the permanent magnet 2 are located on the left side of the armature 34.
6 and the armature 34 and the second
A strong suction force is generated between the portion 42a. On the other hand, on the right side of the armature 34, the magnetic flux C1 generated by the coil 32 and the magnetic flux B generated by the permanent magnet 28 are in opposite directions.
Is weakened by the magnetic flux C1, and the attraction between the armature 34 and the second portion 42b is weakened. Therefore,
The armature 34 is sucked in the X1 direction, loses equilibrium, and leans to the left.

On the other hand, as shown in FIG. 5, the coils 32 are generated in such a manner that a magnetic flux C2 is generated, that is, in a direction opposite to that of FIG.
Is energized, the coil 3 on the left side of the armature 34
2 and the magnetic flux B generated by the permanent magnet 26 are in opposite directions, and thus cancel each other out to form the armature 34.
A weak suction force is generated between the first portion 42a and the second portion 42a. On the other hand, on the right side of the armature 34, the magnetic flux C2 generated by the coil 32 and the magnetic flux B generated by the permanent magnet 28 are superimposed to generate a strong attractive force. Therefore, the armature 34 is sucked in the X2 direction, loses the equilibrium state, and leans to the right.

As the armature 34 tilts, the flapper 36 fixed to the armature 34 also tilts, and the distance between the nozzles 48a and 48b and the flapper 36 changes. According to this displacement, a pair of nozzles 48a and 48
The back pressure of each of b changes. Nozzles 48a and 4
8b is guided to both ends of the spool 62,
The spool 62 is displaced by the change of the back pressure. The displacement of the spool 62 causes the feedback spring 38 connected to the flapper 36 to generate a torque opposite to the magnetic torque of the armature 34, and pulls the flapper 36 back to the neutral position. When the flapper 36 returns to the neutral position, the back pressure of each of the nozzles 48a and 48b becomes equal, and the spool 62 stops at that position.

When the armature 34 is tilted to the left,
As shown in FIG. 6, since the flapper 36 is inclined in a direction in which the distance between the nozzle 48b and the flapper 36 is reduced,
The back pressure of b increases, and the back pressure of the nozzle 48a decreases, and the spool 62 moves in the Y direction. This spool 6
Feedback spring 38 generated by displacement of 2
The flapper 36 is returned to the neutral position as shown in FIG. Although the illustration and description of the case where the armature 36 is tilted to the right is omitted, it will be easily understood from the above description.

Thus, the direction and amount of oil flow are controlled according to the magnitude and polarity of the input current.

According to the electrohydraulic servo valve 10, since the rare earth magnets are used as the permanent magnets 26 and 28, the magnetic flux density can be increased, and the small torque motor 12 can be used.
However, sufficient torque can be obtained. By the way,
In the prior art shown in FIG.
In the case of 2 mm x height 14 mm x depth 23.8 mm, the suction force acting on the armature 2c is 600 gf,
In the electro-hydraulic servo valve 10 shown in FIG. 1, the dimensions of the torque motor 12 are 40 mm wide × 21.6 mm high × 33.3 depth.
In the case of 2 mm, the suction force acting on the armature 34 is 1200
gf was obtained.

When the torque motor 12 is mounted on the electric-to-pressure converter 14, first, after the armature 34 is disposed, a desired horizontal gap G is formed between the armature 34 and each part of the yoke 24 and Permanent magnet 2
Since it suffices to attach 6, 28, a desired gap G can be easily provided between the armature 34 and the lower yoke 18 and 20. Therefore, as in the prior art shown in FIG. 9, the complicated operation of mounting the armature 2c at a predetermined position in the gap between the upper magnetic pole 2a and the lower magnetic pole 2b is not required, and the torque motor 12
As a result, assembly of the electrohydraulic servo valve 10 becomes easy.

The permanent magnets 26 and 28 are connected to the yoke 2
4 may be formed so as to be sandwiched between the left leg portion 30b and the right leg portion 30c of the upper yoke 22, respectively, as long as they are formed at positions equidistant from the center leg portion 30a of the fourth yoke.
Further, it may be formed so as to be sandwiched between the top plate 30d of the upper yoke 22. The coil 32 may be wound around the left leg 30b and the right leg 30c of the yoke 24, respectively.

As shown in FIG. 8, the permanent magnet 26a
And 28a are formed so as to be sandwiched between the upper yoke 22a at positions equidistant from the center of the yoke 24a to the left and right, respectively, and the flapper 36a is arranged so that the armature 34a is aligned with the upper yoke 22a. Good. By doing so, the distance from the armature 34a to the fulcrum A2 can be increased, so that a larger torque can be obtained.

Further, the present invention can be applied not only to a mechanical feedback system but also to an electrohydraulic servo valve of an electric feedback system.

In the above-described embodiment, the case where the present invention is applied to the electrohydraulic servo valve 10 for hydraulic control has been described. However, the present invention is not limited to this, and the present invention is applicable to a fluid made of another liquid or gas. The present invention can be applied to any fluid pressure control device that controls the pressure of the fluid.

[0040]

According to the present invention, since the rare earth magnet is used as the permanent magnet, the magnetic flux density can be increased, and a sufficient torque can be obtained even with a small size.

When a fluid pressure control device is constructed using a torque motor, since a yoke and a rare earth magnet are attached after the armature is arranged, unlike the conventional case, a desired gap is provided between the armature and the yoke. It can be easily provided, and assembling of the torque motor and the fluid pressure control device becomes easy.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a main part of the embodiment of FIG.

FIG. 3 is a perspective view showing a main part of the embodiment of FIG. 1;

FIG. 4 is an illustrative view showing one example of a magnetic flux generated when a coil of a torque motor is energized;

FIG. 5 is an illustrative view showing another example of the magnetic flux generated when the coil of the torque motor is energized;

FIG. 6 is an operation principle diagram showing an example of the operation of the embodiment of FIG. 1;

FIG. 7 is an operation principle diagram showing another example of the operation of the embodiment of FIG. 1;

FIG. 8 is an illustrative view showing another example of the torque motor;

FIG. 9 is an operation principle diagram showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electrohydraulic servo valve 12 Torque motor 14 Electric-pressure conversion part 16 Valve body 24, 24a Yoke 26, 26a, 28, 28a Permanent magnet 30a Central leg 32 Coil 34, 34a Armature 36, 36a Flapper 44 Nozzle block 48a , 48b Nozzle G Gap between armature and yoke

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahiro Urai 1532 Maido, Hiratsuka-shi, Kanagawa Japan Moog Co., Ltd. (72) Inventor Yoshiharu Sugimura 1532 Mado, Hiratsuka-shi, Kanagawa Japan Moog Co., Ltd. F-term (Reference) 3H002 BA01 BB03 BC02 BD04 BE01 5H633 BB04 BB07 GG02 GG16 HH02 HH14 HH22 HH24 HH25

Claims (3)

[Claims] A yoke, a coil wound around the yoke, an armature arranged at a central portion of the yoke with a predetermined gap formed between the yoke and the yoke, and a center of the yoke. A torque motor comprising two rare-earth magnets formed so as to be sandwiched between the yoke at opposite positions and equidistant from a portion. 2. The torque motor according to claim 1, wherein the rare earth magnet is formed so as to be oblique to a direction of a magnetic flux generated in the yoke. 3. A fluid pressure control device using the torque motor according to claim 1.