JP2002022048A - Pressure variable valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure variable valve device being hardly disordered in the control of pressure by the external disturbance. SOLUTION: This pressure variable valve device 2 has at least one double- pole stepping motor element 50 and 60 having the characteristic to be easily in one direction, a worm 40 connected to double-pole rotors 51 and 61 of the double-pole stepping motor element, a worm wheel 32 engaged with the worm, and a rotational pressing mechanism 31 connected to the worm wheel and capable of adjusting the pressure force to a valve element 24 corresponding to the rotation of the worm wheel. Typically, a pair of double-pole stepping motor elements are substantially extended in parallel with each other, and rotors are respectively connected to the worm in such manner that the worm is rotated in one rotating direction G1 by the magnetic field applied to a stator 52 of one of the stepping motor element 50 in one direction, and further rotated in the same rotating direction G1 by the magnetic field applied to a stator 62 of the other stepping motor element 60 in the other direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable pressure valve device, and more particularly, to a variable pressure valve device suitable for use as a shunt valve which is implanted in a body to adjust the pressure of cerebrospinal fluid and the like, and its set pressure. It relates to an adjusting device.

[0002]

2. Description of the Related Art For the treatment of hydrocephalus, etc., the middle of a valve spring is supported by a fulcrum, the tip of the valve spring is brought into contact with a ball acting as a valve body, and the base end of the valve spring is moved around a central axis. Engages with the spiral stepped cam surface formed on the rotatable rotating body, and moves the engagement base end of the spring in the axial direction of the rotating body according to the rotation of the cam surface accompanying the rotation of the rotating body. By adjusting the pressure of the cerebrospinal fluid and the like by providing a shunt valve (branch valve) device that changes the pressing force of the ball by the spring by changing the amount of deflection of the spring in the flow path of the cerebrospinal fluid and the like, It is disclosed in JP-A-60-40063.
In the shunt valve disclosed in Japanese Patent Application Laid-Open No. 60-40063, a multipolar rotor in which N and S poles are alternately arranged along the circumferential direction is integrally fixed to the rotating body.
By adjusting the rotational position of the multi-pole rotor, the valve pressure of the shunt valve is adjusted (FIGS. 17 to 29 of the publication). When adjusting the rotational position of the multi-pole rotor, two sets of electromagnets having a pair of magnetic poles are arranged on the body surface along a direction orthogonal to each other, and the two sets of electromagnets are alternately and sequentially turned in opposite directions. (FIG. 27).

[0003]

However, in the case of the variable pressure shunt valve or the variable pressure valve device, in the environment where the direction of the external magnetic field applied to the entire shunt valve changes, the variable pressure is not intended. There is a risk that changes will occur. That is, when a patient such as hydrocephalus, for example, in which a shunt valve is buried under the scalp of the head or the like, undergoes a head examination / diagnosis by an MRI (magnetic resonance imaging) apparatus, the patient may be subject to MRI.
In the apparatus, the inspected / diagnosed unit is oriented in various directions with respect to a strong and spatially uniform main magnetic field which is typically applied in the Z direction of the apparatus. When the shunt valve receives a magnetic field whose direction changes in the same order as when adjusting the rotational position of the rotating body of the shunt valve, there is a possibility that an unintended deviation of the set pressure may occur. Further, when trying to adjust the rotational position of the multi-pole rotor, not only is it necessary to accurately position the adjusting electromagnet to the rotor to some extent, but also the extracorporeal position almost facing the rotor under the body. It is not always easy to position the adjusting electromagnet with desired accuracy, for example, it is necessary to arrange the magnetic poles of the electromagnet. Furthermore, in a multi-pole rotor, since there is a possibility that it may not always be held at a specific rotation position, the above adjustment may be complicated. Although the gazette also suggests the use of a two-pole rotor on page 12, lower right column, lines 7 to 12, etc., the "two-pole rotor" suggested here is the same as that of the gazette. As shown in FIG. 30 and FIG. 31, a special rotor having a four-way characteristic with a cross shape,
It is not something that can be called a two-pole rotor.

[0004] The present invention has been made in view of the above points, and an object of the present invention is to provide a variable pressure valve device in which pressure control is less likely to be disturbed by external disturbance.

[0005]

According to the present invention, at least one two-pole step motor element having a characteristic of being easily rotated in one direction is provided to achieve the above object.
A worm coupled to the two-pole rotor of the two-pole step motor body, a worm wheel meshed with the worm, and a rotary press coupled to the worm wheel and capable of adjusting a pressing force on the valve element according to the rotation of the worm wheel. And a mechanism.

In the variable pressure valve device according to the present invention, the rotational driving force of the step motor body is connected to the worm wheel from the worm connected to the rotor of the step motor body via the worm wheel meshed with the worm. Is transmitted to the rotated pressing mechanism. Between the worm and the worm wheel, the rotation is easily transmitted from the worm to the worm wheel.On the other hand, the rotation from the worm wheel to the worm is difficult to be transmitted. The rotation of the worm wheel is prohibited by the worm meshing with the worm wheel even if the worm wheel is generated. Therefore, there is little possibility that the setting state of the variable pressure valve device changes due to unexpected disturbance at the valve body or the rotation pressing mechanism. .

Further, in the variable pressure valve device of the present invention, the rotation of the worm wheel is controlled by a two-pole step motor element having a characteristic of being easily rotated in one direction. In this two-pole step motor, the direction of the magnetic flux passing through the stator is reversed, and the rotor is rotated in the one direction by repeating the half-rotation of the two-pole rotor.
Since the stator is made of a material having a high magnetic permeability and provides a magnetic flux path or a magnetic path, for example, in a spatially uniform magnetic field, even if the orientation of the two-pole step motor body changes to some extent, the two-pole step motor body As long as the direction of the magnetic flux passing through the stator along the extending direction of the stator is kept constant, the magnitude of the magnetic flux passing through the stator can be kept practically constant, so that the rotor is at the same rotational position with respect to the stator. Can be kept.

Accordingly, for example, when this valve device is used as a shunt valve and placed in a so-called strong magnetic field in the Z-axis direction of the MRI device, even if the orientation of the motor element, that is, the orientation of the stator is changed to some extent, In this case, the rotational position of the bipolar rotor with respect to the stator can be kept as it is.
Even when the rotational position of the rotor with respect to the stator changes, it only rotates by 180 degrees. That is, such a 180-degree rotation of the rotor occurs when the direction of the valve device exceeds a specific direction (direction in which the direction of the magnetic flux passing through the stator is reversed) with respect to the direction of the strong magnetic field. Only when fluctuating. Therefore, there is little possibility that the two-pole rotor is further rotated.

A two-pole step motor element having a characteristic of being easily rotated in one direction is typically of a type usually used in a timepiece or the like, and has a circular hole having a diameter close to the entire width of an elongated stator. A magnetized disk-shaped two-pole rotor is arranged, and a stator is provided with a concave portion that defines a magnetostatically stable position of the rotor on a circumferential surface facing the diametrical direction of the circular hole, and a circular magnetic path is formed by narrowing a magnetic path. A pair of notches for facilitating the leakage of magnetic flux into the hole are provided on the outer surface of the peripheral wall of the circular hole at both ends in the width direction of the stator. In a state where the external field is not working, the rotor is kept at a magnetostatically stable rotational position, and any deviation from the position is returned to the original position by a magnetostatic force acting as an index torque. When a pulse magnetic field or a magnetic field pulse is applied in a direction for rotating the rotor in the extending direction of the stator, the rotor is rotated in a direction in which a portion located inside the notch moves toward the concave portion of the circular hole, and the initial rotational position is set. Reaches a statically stable position rotated by 180 degrees. When the rotor is to be further rotated, a pulse magnetic field or a magnetic field pulse for rotating the rotor is further applied in the extending direction of the stator. However, the direction of the magnetic field pulse at this time is opposite to the initial direction. On the other hand, even when a magnetic field in a direction opposite to the direction in which the rotor rotates is applied in the extending direction of the stator, the rotor is not rotated. In order to rotate the rotor in the opposite direction, a pulse magnetic field for oscillation is applied to the rotor, and then a pulse magnetic field for rotational driving is applied at a predetermined timing.

[0010] The worm has a tooth having a spiral pitch as small as possible within a range not requiring an excessive number of rotations, so that rotation in the reverse direction can be suppressed as much as possible and rotation of the worm wheel caused by rotation of the worm can be finely adjusted. It is preferable to have However, the degree of the small pitch may be set in a desired range in consideration of other conditions.

[0011] The variable pressure valve device of the present invention preferably comprises
It has at least one pair of two-pole step motor bodies, and the pair of two-pole step motor bodies extends substantially parallel to each other and is oriented in one direction with respect to the stator of one of the step motor bodies. Each of the worms is rotated in one rotation direction by a magnetic field, and the worm is rotated in the one rotation direction by a magnetic field applied in a direction opposite to the one direction with respect to the stator of the other step motor body. The rotor is connected to the worm.

When the valve device is used as a shunt valve, the pair of step motor bodies are respectively opposed to each other even if the MRI device is placed in a spatially practically uniform strong magnetic field as described above. In addition to trying to rotate the worm, even if the rotational driving force of one step motor body is larger than the rotational driving force of the other step motor body, the other step motor body Since it acts not only to perform the reverse rotation drive but also to prevent the rotation, the possibility that the valve device is erroneously adjusted can be minimized.

In this case, the directions in which the step motors are easily rotated may be opposite to each other. However, in order to facilitate the adjustment of the valve pressure, each of the pair of two-pole step motor bodies has one of the two pole motors. Preferably, the rotation direction coincides with the rotation direction in which the respective rotors are easily rotated.

In the variable pressure valve device of the present invention, when at least one pair of two-pole step motor elements is provided, the step motor elements may be arranged in parallel at one end of the worm. Typically, a pair of rotors are coaxially fixed to the worm at both ends of the worm in order to provide a stable rotational torque to the valve and minimize the size of the valve device. In this case, the worm is meshed with the worm wheel at the intermediate portion in the longitudinal direction. In any case, the worm is preferably supported at both ends by a pair of bearings.

In the variable pressure valve device according to the present invention, the rotary pressing mechanism may be any structure as long as it is connected to the worm wheel and the pressing force on the valve body can be adjusted according to the rotation of the worm wheel. However, in order to minimize the movable parts and to reduce the size of the apparatus as much as possible, the rotation pressing mechanism typically includes a cam member integrally formed with a worm wheel and having a cam surface, An elastic member engaged with the surface at a first end and a second end engaged with the valve body.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described with reference to a preferred embodiment shown in the accompanying drawings.

[0017]

1A, 1B and 1C show a preferred embodiment of a valve system 1 according to the present invention. The valve system 1 adjusts the pressure of the cerebrospinal fluid of the patient such as hydrocephalus, for example, under the patient's scalp 101 (for example, at a depth of about several mm from the body surface).
A shunt valve 2 as a variable pressure valve device embedded on the body 2; and a set pressure adjusting device 3 disposed on the body surface to adjust a set pressure ΔP by the shunt valve 2.

As shown by an imaginary line in FIG. 1B, the shunt valve 2 is connected / arranged, for example, in the middle of a cerebrospinal fluid conduit 5, and is connected to the cerebrospinal fluid in the upstream conduit or conduit portion 5a. Of the shunt valve 2 is compared with the pressure P0 of the cerebrospinal fluid in the downstream conduit or conduit 5b.
P should not be higher than P,
Set and adjust so as to be 0 + ΔP or less. For example,
When the pressure P0 actually coincides with the atmospheric pressure, if P0 = 0 with respect to the atmospheric pressure, P = ΔP. In addition,
The shunt valve 2 may be used as a valve device for adjusting the pressure such that the pressure of the downstream conduit portion 5b is equal to or higher than a predetermined pressure P0 (= P-ΔP).

The shunt valve 2 has a valve device main body or valve housing 10 made of silicone resin, polycarbonate or the like. The valve device main body 10 includes a bottom wall 11 (FIG. 1C) placed on a skull 102, a top wall 12 located below the scalp 101 (FIG. 1C), and a skull 102. Side walls 13 and 14 (FIG. 1 (b)) and end wall 1 which rise perpendicular to the surface of the skull 102 with the scalp 101
5 and 16, and these walls 11 to 16 define or define the internal chamber 17. In addition, the wall portions 11 to 1
6, the valve device body 10 having a box shape as a whole.
Is formed by fitting the lower body 10a and the upper body 10b in a liquid-tight manner at the mutual engagement portions 10a1 and 10b1. An inlet 18 to which the upstream conduit 5a is connected is formed in the side wall 13 and a downstream conduit 5b is formed in the end wall 16.
The outlet part 19 to which is connected is formed.

A portion of the side wall 13 where the hole 20 of the inlet 18 is open to the internal chamber 17 is provided with a valve seat 2 made of hard ceramic such as sapphire or ruby having a frustoconical seating surface.
The ball seat 21 is provided with a ball-shaped valve member, that is, a ball valve or a valve ball 22 as a hard ceramic valve body so as to be seated thereon. On the ball valve 22, an elastic arm or one end or a tip end portion 25 of a valve spring 24 rotatable in the A1 and A2 directions around the fulcrum portion 23 is pressed toward the valve seat 21 in the F1 direction. The distal end portion 25 of the valve spring 24 is smoothly curved in a convex shape with respect to the ball valve 22. Therefore, the entrance 1
Pressure difference P-P0 between the pressure P at 8 and the pressure P0 at the outlet 19
Is the pressing force of the valve spring 24 in the F1 direction and the ball valve 22
When the pressure ΔP exceeds the pressure ΔP defined by the pressure receiving area, an opening or a valve flow path B is formed between the surface of the ball valve 22 and the seat surface of the valve seat 21, and the pressure P in the upstream-side conduit portion 5 a is reduced. The chamber 17 is released downstream.

The fulcrum 23 is, for example, a valve housing 10
Both ends of the bottom wall 11 and the top wall 12 are rotatably supported via bearings, and have pins or shafts 26 provided with slits at longitudinally intermediate portions. The flaky valve spring 24 is fitted into a slit of the shaft 26 and is fixed to the shaft 26 at the fitting portion. The other end or the base end 27 of the valve spring 24 is formed on the peripheral surface 33 of the circumferential cam 31 of the composite cam wheel or the cam / worm wheel composite 30 in which the circumferential cam 31 and the worm wheel 32 are integrally formed. It is imposed. The composite cam wheel 30 also has a bottom wall 11 and a top wall 1
2, both ends are supported rotatably in the C1 and C2 directions via bearing portions 34 and 35.

The circumferential surface 33 of the circumferential cam 31 is shown in FIG.
From the center axis C, the distance from the starting end D0 having the smallest radius to the ending end De having the largest radius is C2.
The radius gradually and smoothly increases in the direction, and a locking surface 37 extending in the radial direction is formed at the maximum diameter portion De. Accordingly, as shown in FIG. 1B, when the base edge 28 of the base end 27 of the valve spring 24 comes into contact with the locking surface 37, further rotation of the compound cam wheel 30 in the C2 direction is It is forbidden. This rotational position of the composite cam wheel 30 is the initial position E
become. In this initial position E, the proximal end 27 of the valve spring 24
Actually engages the position D1 closest to the minimum diameter portion D0,
The force applied from the circumferential cam 31 of the compound cam wheel 30 to the valve spring 24 in the A1 direction is minimized, and the force of the distal end 25 of the valve spring 24 supported by the fulcrum 23 pressing the ball valve 22 in the F1 direction is also minimized. become. Pressure ΔP at this minimum pressing force
Is zero, but a value slightly larger than zero (for example, a value equal to or slightly smaller than the lower adjustment pressure (for example, about 5
0 to 100 Pa (about 5 to 10 mm water column)).

The larger the rotation angle α (not shown) at which the cam 31 is rotated in the direction C1 from the position shown in FIG. 1B, the more the peripheral surface 33 of the cam 31 becomes the proximal end 27 of the valve spring 23.
Is greatly displaced in the A1 direction, the pressing force of the ball valve 22 in the F1 direction by the distal end portion 25 of the valve spring 23 also increases, and the set differential pressure ΔP also increases.

In the illustrated example, since the circumferential cam 31 is used, the rotation axis C of the compound cam wheel 30 and the axis of the fulcrum 23 of the valve spring 24 are parallel to each other. A helical cam surface may be used. In this case, the axis of the fulcrum 23 of the valve spring 24 is oriented at an angle of, for example, 90 degrees with respect to the rotation axis C of the compound cam wheel 30. Thus, the valve seat 21 and the inlet or the inlet 18 are formed on the bottom wall 11 of the valve housing 10.

The worm wheel 32, whose teeth are cut at equal intervals on the peripheral surface, is supported at both ends by bearings in the bearing holes of the side walls 13 and 14 via bearings 41 and 42 so as to be rotatable in the G1 and G2 directions. Wall 11, top wall 12, and end wall 15,1
6 is engaged with a worm 40 extending parallel to the worm. In the illustrated example, the worm 40 is formed with spirally extending teeth 43 so that the worm wheel 32 is rotated in the C1 and C2 directions in accordance with the rotation of the worm 40 in the G1 and G2 directions. The helical pitch of the teeth 43 of the worm 40 is small, and the angle at which the worm wheel 32 rotates every half rotation of the worm 40 is relatively small. For example, from the initial position E shown in FIG. 1B, the worm 40 rotates a given number of times (for example, 16 times) in the G1 direction (for example, 16 times) (32 half-turns), and the composite cam wheel has an angle corresponding thereto. 30 is C
When rotated in one direction, the C2 of the worm wheel 32 teeth
The end Hs in the direction contacts the teeth 43 of the worm 40, and further rotation in the C1 direction is prohibited. At this time, the peripheral surface portion Ds of the cam 31 presses the base end portion 27 of the valve spring 24 with the maximum pressing force (the corresponding maximum adjustment pressure ΔPmax is set, for example, to about 4,000 Pa (400 mm water column)). . Since the spiral pitch of the teeth 43 of the worm 40 is small, the worm 40 is not actually rotated even if a considerably large rotational force is applied to the compound cam wheel 30 including the worm wheel 32. In the above,
The rotation pressing mechanism includes a compound cam wheel 30 and a valve spring 24.

Two-pole rotors 51 and 61 are fixed coaxially with the worm 40 near both ends of the worm 40. As can be seen from FIGS. 1A to 1C, the rotors 51 and 61 are each made of a permanent magnet magnetized in the diameter direction, and the directions of magnetization of the bipolar rotors 51 and 61 are parallel and opposite. It is. On the inner surfaces of the side walls 13 and 14 of the valve device main body 10, stators 52 and 62 forming the two-pole step motor bodies 50 and 60 in cooperation with the respective rotors 51 and 61 are fixed.

In this example, the step motor bodies 50, 6
0 so that the rotational drive characteristics of the
End 68 extends only opposite the end 58 of the stator 52, but if desired, the stator 6
The second end 68 may extend to near the end wall 15 of the valve device main body 10. In addition, the height of the side wall 13 and the like (the height of the chamber 17) is made larger than the outer diameter of the valve seat 21, and the end 58 of the stator 52 is extended to the vicinity of the end wall 15. You may leave. In this case, the width of the stator 52 or the width of the magnetic flux path may be slightly narrowed at the valve seat 21 as long as the width is not large enough to be saturated by the control magnetic field pulse. Further, the ends 58 and 59 of the stator 52 and the ends 68 and 69 of the stator 62 are provided on the top wall 12 so that a magnetic field can be applied from above the top wall 12 in a direction substantially perpendicular to the top wall. As shown in FIG.
The stators 52 and 62 may have a U-shape when viewed in a cross section as shown in FIG.

Returning to the embodiment shown in the drawing, further explanation will be given.
The stators 52 and 62 extending in the X direction are
The circular holes 53 and 63 into which the rotor 61 is rotatably fitted, and the circumferential walls of the circular holes 53 and 63 for defining the magnetostatic stable positions of the bipolar rotors 51 and 61 with respect to the stators 52 and 62 are diametrically oriented. A pair of recesses 54, 55 and 64, 65 formed at the matching positions, and (a) and (c) of FIG.
Upper and lower notches or notches for narrowing the magnetic flux paths of the stators 52 and 62 so as to generate leakage magnetic flux in the circular holes 54 and 55 for applying rotational torque to the bipolar rotors 51 and 61 at the magnetostatically stable positions as shown in FIG. Parts 56, 57 and 66,
67. 1A and 1C, the concave portions 54, 55 and 64 of the stators 52 and 62,
The orientation or position of 65 and notches 56, 57 and 66, 67 are practically identical. Therefore, the stators 52, 62
Each time the direction of the magnetic field in the X direction applied to
1 and 61 make a half turn in the G1 direction, and the composite cam wheel 30 turns in the C1 direction by an angle corresponding to a half turn of the worm 40. Since the positions of the recesses 54, 55 and 64, 65 and the notches 56, 57 and 66, 67 of the stators 52 and 62 coincide with each other and the two-pole rotors 51, 61 are magnetized in opposite directions, the rotors 51, 61 The directions of the magnetic fields to be applied by the adjusting device 3 to the stators 52, 62 to provide a rotational driving force are opposite to each other.

When the rotors 51 and 61 are to be rotated in the direction G2, as is well known, a moderate pulse is applied to the adjusting device 3 to oscillate the rotors 51 and 61 with a pulse magnetic field. When the 61 largely swings in the G2 direction, a pulse magnetic field may be applied to the rotors 51 and 61 again so as to rotate the rotors 51 and 61 in the opposite direction.

In the shunt valve 2 configured as described above, in order to adjust the pressure ΔP, first, the electromagnet 7
0 of the pole pieces or the pole pieces 71, 72 are the end walls 15, 1
The electromagnet 70 is arranged on the surface of the scalp 101 so as to face the adjacent ends 58 and 59 of the stator 52 through the inner wall 6, and the magnetic poles 81 and 82 of the electromagnet 80 are connected to the end walls 15 and 16.
The electromagnet 80 is arranged on the surface of the scalp 101 so as to face both ends 68 and 69 of the stator 62 via the. here,
The adjusting device 3 includes the electromagnets 70 and 80 and the motor body 5
0, 60 rotor 51, 61 forward direction G1 and reverse direction G
The width, strength (magnitude), rise / fall speed (incline) of the output current pulse to the electromagnets 70 and 80 so that the pulse-like magnetic field to be rotated by 2 is generated by the electromagnets 70 and 80,
It comprises a power supply 90 whose pulse interval and the like can be adjusted.

Next, the reverse rotation pulse of the motor bodies 50 and 60 is applied to the electromagnets 70 and 80 from the power supply 90 of the adjusting device 3 to rotate the rotors 51 and 61 in the reverse direction, that is, in the G2 direction. Rotor 5 of motor body 50, 60
Each time the worm wheel 43 rotates a half-turn in the G2 direction by rotating the worm wheel 32 by a half angle in the G2 direction, the worm wheel 32 rotates by an angle corresponding to the C2 direction, and the composite cam wheel 30 including the worm wheel 32 integrally is also provided. Rotate in the C2 direction by the same angle. The rotation of the compound cam wheel 30 in the C2 direction is performed regardless of the initial rotation position of the compound cam wheel 30.
Until the base edge 28 of the composite cam wheel 30 comes into contact with the locking surface 37 of the circumferential cam 31 of the compound cam wheel 30. Base edge 2 of valve spring 24
8 comes into contact with the locking surface 37 of the circumferential cam 31 of the compound cam wheel 30, the rotational load or resistance of the compound cam wheel 30 rapidly increases, and accordingly, the rotational load of the worm 40, that is, the motor element 50, Since the rotational load of the 60 rotors 51 and 61 suddenly increases, the output of the power supply 90 sharply increases. When the output sharply rises, it is known that the composite cam wheel 30 has been set to the initial position, and thus the supply of the reverse current from the power supply 90 is temporarily stopped. In addition, even if the detection of the rise and the stop of the power supply are manually performed, a means for detecting the output current or the output voltage and a means for determining whether the magnitude of the detected output exceeds a predetermined value. And an initial position detection power supply control means including power supply stop control means for stopping power supply from the power supply when the determination means determines that the detection output exceeds a predetermined value. You may keep it.

Next, a pulse for normal rotation is given to the electromagnets 70 and 80 from the power supply 90, and the rotors 51 and 61 of the motor bodies 50 and 60 are rotated in the G1 direction by half a turn. When the electromagnets 70 and 80 are magnetized by the forward rotation pulse,
Since the rotors 51, 61 of the motor bodies 50, 60 are 180 degrees out of phase with each other in the direction of rotation,
For example, when magnetizing the electromagnet 70 so that the magnetic pole 71 of the electromagnet 70 close to the end wall 15 becomes the N pole, the electromagnet 80 so that the magnetic pole 81 of the electromagnet 80 close to the end wall 15 becomes the S pole. Will be magnetized. That is, the rotors of the two motor bodies 50 and 60 are connected in the same normal rotation direction G1.
In order to rotate the stator 52 and 62, the stators 52 and 62 are magnetized in mutually opposite directions (this point is not described in detail, but the same applies to the above-described reversal or reverse rotation).

The rotors 51, 61 of the motor bodies 50, 60
In response to the half rotation of the worm 40 in the G1 direction due to the half rotation of the worm wheel 32, the circumferential cam 31 integral with the worm wheel 32 is rotated in the C1 direction by a corresponding fixed angle, and the valve spring 24 is rotated.
Pushes the base end 27 of the ball valve 22 in the A1 direction and rotates the front end 25 in the A1 direction.
Is increased by a corresponding amount in the F1 direction. The relationship between the number of half rotations of the worm 40 in the G1 direction and the pressing force in the F1 direction by the distal end portion 25 of the valve spring 24 (in other words, the pressure difference ΔP set or adjusted by the shunt valve 2) has a one-to-one correspondence. Therefore, based on this relationship, the pressure set by the shunt valve 2 can be adjusted to a predetermined value by rotating the worm 40 or the rotors 51 and 61 halfway in the G1 direction the number of times necessary to give the predetermined pressure difference ΔP. .

In this case, since the set pressure ΔP is reset from the initial state E, the pressure can be set or adjusted without knowing in advance what rotational position the composite cam wheel 30 is in. is there. Therefore, it is not necessary to directly detect the setting state of the pressure of the shunt valve 2 buried under the body, and it is not necessary to consider the high reliability of the detection accuracy.

In the shunt valve 2, since the worm wheel 32 of the compound cam wheel 30 is meshed with the worm 40, external disturbance to rotate the compound cam wheel 30 in the C1 direction or the C2 direction is generated. C1 of the worm wheel 32 of the compound cam wheel 30 even if added to the wheel 30
Since the rotation in the direction and the C2 direction is actually prohibited by the worm 40 having a small pitch of the teeth 43, there is little possibility that the compound cam wheel 30 and the worm 40 are rotated by mechanical disturbance.

Further, in the shunt valve 2, since the rotors 51 and 61 are magnetostatically stable at the positions shown in the figure, there is a small rotation in the G1 direction or the G2 direction which deviates from the stable position. Also, the rotor 51, 61 receives a restoring force for returning the rotor 51, 61 to its original position by a magnetostatic force acting between the magnetic poles of the rotors 51, 61 and the inner peripheral surfaces of the holes 53 of the stators 52, 62. Therefore, even if a force is applied to rotate the rotors 51 and 61 and the worm 40 to some extent in the G1 and G2 directions due to external disturbance, the rotation is not affected by the stators 52 and 62.
Can be expected to be minimized and restored by the holding force (index force) for holding the rotors 51 and 61 at the magnetostatic stable rotation position.

As described above, in the shunt valve 2, in order to rotate the rotors of the two motor bodies 50 and 60 in the same forward direction G1, the stators 52 and 62 are magnetized in opposite directions. There is a need. On the other hand, when the patient with hydrocephalus enters a strong magnetic field of the MRI apparatus and receives a spatially almost uniform strong magnetic field in one direction to be diagnosed by MRI, the stators of the two motor elements 50 and 60 are 5
A magnetic field of the same direction is applied to 2,62. Under such a spatially uniform magnetic field, the motor body 50, 6
The magnetic field applied to one of the zero stators 52, 62 is directed to rotate the rotor 51 or 61 associated with the one stator 52 or 62, but is applied to the other stator 62 or 52. The magnetic field acts to lock the rotation of the rotor 61 or 51. As a result, the worm 40 integrated with both of the two rotors 51 and 61 is not rotated, and the pressing force in the F1 direction by the valve spring 24 does not change. This is shunt valve 2
Is always true regardless of orientation.
Therefore, in the shunt valve 2, even if there is a magnetic disturbance outside, the possibility that the set pressure of the shunt valve 2 is affected or disturbed by the magnetic disturbance can be minimized.

In the above description, the pair of motor bodies 50, 60 are provided at both ends in the axial direction of the worm 40. However, if desired, the motor body 60 may be provided on the side wall in addition to the motor body 50. The motor body 50 may be provided in the vicinity of the side wall portion 14 in addition to the motor body 60 in the vicinity of the portion 13. In any case, it is preferable that both ends of the shaft of the worm 40 be supported at both ends via bearings 41 and 42 of the side walls 13 and 14.

In the above description, an example has been described in which the forward rotation directions of the rotors 51, 61 of the two motor bodies 50, 60 coincide with each other. The normal rotation direction of the rotors 51 and 61 may be reversed. For example, when the forward rotation direction of the rotor 51 of the motor body 50 is opposite (when the stator configuration and the rotor arrangement are mirror-symmetrical to those shown in FIG. 1A), the worm When the motor 40 is to be rotated in the G1 direction, a pulse magnetic field for normal rotation is applied to the stator 62 of the motor body 60 and the stator 5 of the motor body 50 is rotated.
2 may be provided with a set of pulse magnetic fields for reverse rotation. When the worm 40 is to be rotated in the G2 direction, a pulse magnetic field for normal rotation is applied to the stator 52 of the motor body 50, What is necessary is just to apply a set of pulse magnetic fields for reverse rotation to the stator 62. On the other hand, when the MRI apparatus is exposed to a spatially substantially uniform strong magnetic field, the temporal variation patterns of the magnetic fields simultaneously applied to the rotors 51 and 61 become practically the same. In this case, there is no possibility that an unexpected rotation of the worm 40 will occur, and there is no possibility that an unexpected change will occur in the set pressure of the shunt valve 2.

Further, in the above description, the worm 40 is supported by the pair of motor bodies 50, 60. However, if desired, at least one of the motor bodies 50, 60 is, for example, similar to each other. It may be composed of a plurality of motor elements having various configurations.

Further, in the above, the worm 4
Although 0 is supported by the pair of motor bodies 50, 60, depending on the case, one of the motor bodies 50, 60 may not be provided. Also in this case, the G of the worm 40
1, that the rotation in the G2 direction is caused to adjust the pressing force and the initial position setting by the valve spring 24 in the same manner, and that the worm 40 of the C2 direction rotation of the compound cam wheel 30 has a similar blocking function. It will be clear that a magnetostatic restoring force acts on the rotor 51 or 61 as well.

In the case of a single motor element, the possibility of unexpected rotation under a strong magnetic field cannot be completely avoided. However, since this rotation is also performed in units of half rotation, the stator is As long as the direction of the magnetic field applied to the rotor via the rotor does not fluctuate extremely alternately, it can be expected that the number of occurrences of unexpected rotation of the rotor can be suppressed to a relatively small range.

[Brief description of the drawings]

FIG. 1 shows a pressure regulating system having a shunt valve as a variable pressure valve device according to a preferred embodiment of the present invention, wherein (a) shows one motor element in detail and (b) IA shows -Explanatory drawing taken along line IA (however,
(B) omits a ball valve, etc.), and (b) is an explanatory plan view of the pressure adjustment system in a state where an upper member (lid member) of a valve device main body is removed (however, a valve seat, an inlet, an outlet). And the bearing of the worm are shown broken),
(C) is a cross-sectional explanatory diagram of the IC-IC line of (b).

[Explanation of symbols]

REFERENCE SIGNS LIST 1 pressure adjusting system 2 variable pressure valve device 3 pressure adjusting device 5, 5 a, 5 b conduit 21 valve seat 22 ball valve (valve ball) 23 fulcrum 24 valve spring 30 worm wheel / circumferential cam composite (composite cam wheel) 31 Circumferential cam 32 Worm wheel 40 Worm 50, 60 Motor body 51, 61 Dipole rotor 52, 62 Stator 70, 80 Electromagnet 71, 72, 81, 82 Magnetic pole 90 Power supply C1, C2 Rotation direction F1 Press direction G1, G2 Rotation direction

Claims (6)

[Claims] At least one two-pole step motor body having a characteristic of being easily rotated in one direction, a worm coupled to a two-pole rotor of the two-pole step motor body, and a worm wheel meshed with the worm And a rotation pressing mechanism coupled to the worm wheel and capable of adjusting the pressing force on the valve element according to the rotation of the worm wheel. 2. A motor having at least one pair of two-pole step motor bodies, wherein the pair of two-pole step motor bodies extend substantially parallel to each other, and are arranged with respect to a stator of one of the step motor bodies. The worm is rotated in one rotation direction by a magnetic field applied in one direction, and the worm is rotated in the one rotation direction by a magnetic field applied in a direction opposite to the one direction with respect to the stator of the other step motor body. 2. The variable pressure valve device according to claim 1, wherein each rotor is coupled to the worm. 3. The variable pressure valve device according to claim 2, wherein, for each of the pair of two-pole step motor elements, the one rotation direction coincides with a rotation direction in which each rotor is easily rotated. 4. The variable pressure valve device according to claim 2, wherein a pair of rotors are coaxially fixed to the worm at both ends of the worm, and the worm meshes with the worm wheel at an intermediate portion in the longitudinal direction. . 5. A cam member having a cam surface integrally formed with a worm wheel, a resilient member having a first end engaged with the cam surface and a second end engaged with a valve body. The variable pressure valve device according to any one of claims 1 to 4, comprising: 6. The variable pressure valve device according to claim 1, wherein the variable pressure valve device is configured to be embedded in a body.