Abstract:
A method for driving a thrust body with a bidirectional linear solenoid drive having at least in each case one first actuator and one second actuator includes the steps of providing the at least one first actuator with at least one coil and a yoke and applying force alternately to the thrust body by interacting the first actuator with at least one armature ring. The armature ring is rotated with the second actuator to thereby axially shift the thrust body by the rotation of the armature ring. The thrust body is, then, shifted axially and is subsequently fixed in position with the thrust body being shifted in steps in this way until it has reached its respective final position. Also provided is a configuration for carrying out the method.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application is a continuation, under 35 U.S.C. § 120, of copending international application No. PCT/EP02/00471, filed Jan. 18, 2002, which designated the United States.  
         BACKGROUND OF THE INVENTION  
       FIELD OF THE INVENTION  
         [0002]    The invention relates to a method for driving a thrust body by a bidirectional linear solenoid drive, and to a configuration for carrying out the method according to the invention. In the case of very deep holes, for example, oil boreholes, the components and systems that are used are subject to particular requirements: temperatures of up to 225° C., pressures up to 700 bar, and corrosive atmospheres results in extreme design conditions for the technology that is used. The space available for a component is determined by the production tube or feed tube and, thus, limits the options for the construction of these components.  
           [0003]    Restrictor valves, for example, in holes such as these are nowadays, therefore, generally driven by hydraulic systems. These can apply the high required actuating forces of about 25,000 N and can carry out the actuating movement, which is typically 200 mm. It is difficult to supply compressed fluid, particularly in the case of multilateral holes with branches into side arms. Long oil supply lines for these hydraulics have to withstand temperature differences: for example, typical temperature values of 200° C. in a deep borehole, 4° C. at the seabed, and −20° C. at the feed point or feed platform. These temperature differences cause non-uniform material expansion, which frequently results in malfunctions.  
           [0004]    A conventional actuating drive for such a restrictor valve typically has no more than five positions, that is to say, closed, a quarter open, half open, three quarters open, and open so that only correspondingly coarse control is achieved. Furthermore, for applications such as these, the required life is, frequently, at least ten years, with high reliability.  
           [0005]    If electrical drives are used to improve the controllability in this case, for example, stepping motors, then the required drive force can be applied only through a transmission system due to the shortage of space available in the boreholes. The number of components, in particular, the number of moving parts of such a drive system has a negative effect, however, on the reliability of these alternative drives.  
           [0006]    The VDI Progress Reports, Series 8, No. 547 “Untersuchung der Systemdynamik eines fehlertoleranten elektrohydraulischen Stellantriebs mit Direct-Drive-Ventil” [Investigation into the system dynamics of a fault-tolerant electro-hydraulic actuating drive with a direct-drive valve] by Dipl.-Ing. Uwe Klingauf, Taufkirchen, disclose an electromagnetic drive for aircraft construction, which can apply a high drive force, but whose travel is restricted to about 0.8 mm. The drive transmits the force to a shaft that is, correspondingly, deflected through about 0.8 mm. The deflection acts through a main control valve on a hydraulic power stage, which, in the end, is the actuating element of the control system.  
         SUMMARY OF THE INVENTION  
         [0007]    It is accordingly an object of the invention to provide a method and configuration for driving a thrust body by a bidirectional linear solenoid drive that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that drives a thrust body without any procedural restriction to the thrust movement and, in the process, produces high thrust forces, for example, as is required to adjust a valve in deep boreholes for feeding oil. Also provided is a configuration for carrying out the method according to the invention that operates with high reliability over a long life and has a simple and robust design.  
           [0008]    With the foregoing and other objects in view, there is provided, in accordance with the invention, a method for driving a thrust body, including the steps of providing a bidirectional linear solenoid drive with at least one first actuator and one second actuator, providing the first actuator with at least one solenoid and a yoke, and shifting the thrust body in steps until the thrust body has reached a respective final position by applying force alternately to the thrust body by interacting the first actuator with at least one armature ring and rotating the armature ring with the second actuator to thereby axially shift the thrust body by the rotation of the armature ring and subsequently fix the thrust body in position.  
           [0009]    Accordingly, the invention proposes that the method for driving a thrust body be carried out by a bidirectional linear solenoid drive having at least in each case one first and one second actuator, with the at least one first actuator being provided with at least one coil and a yoke and interacting with at least one armature ring that applies force alternately to the thrust body. The thrust body is, then, shifted axially by the at least one armature ring, which is rotated by the at least one second actuator acting on it, and is subsequently fixed in position, with the thrust body being shifted in steps in this way until it has reached its respective final position.  
           [0010]    In accordance with another mode of the invention, the drive power is, advantageously, supplied electrically and is free of the normal mechanical risks of power—transmitting lines for a hydraulic system. The invention makes it possible to move a thrust body in any desired number of individual steps with lengths, for example, of 1 mm or 2 mm. This allows a drive system with an accuracy corresponding to the step length of an individual step, for example, for a valve, when the thrust body is used as an actuating element for the valve. Furthermore, this allows a specific flow rate through a pipeline to be set in a particularly simple manner in that the thrust body produces a correspondingly exact, predetermined valve position.  
           [0011]    The bidirectional linear solenoid drive is, then, operated as a drive for a flow control valve.  
           [0012]    In accordance with a further mode of the invention, the armature ring or the at least one second actuator interacting with a latching apparatus such that the thrust body is fixed in position by the latching apparatus at least when the armature ring is not acting on the thrust body.  
           [0013]    Such a refinement results in a particularly simple drive and simple coordination of the process steps by the latching apparatus and the armature ring or the at least one second actuator.  
           [0014]    In accordance with an added mode of the invention, the method is, advantageously, simplified if the latching apparatus carries out at least one rotary movement in order to fix the thrust body in position at times. This means that the latching apparatus and the at least one armature ring substantially carry out only rotary movements about the longitudinal axis. However, the latching apparatus may also be moved by at least one third actuator and can, then, advantageously be driven autonomously.  
           [0015]    In accordance with an additional mode of the invention, the thrust body is to be acted on in an interlocking manner by the at least one first actuator. This, therefore, allows the axial force to be transmitted between the at least one armature ring and the thrust body in a simple manner.  
           [0016]    In accordance with yet another mode of the invention the at least one armature ring interacts with the thrust body in that the at least one armature ring is rotated in one rotation direction about the longitudinal axis and the latching apparatus causes latching, which, in each case, fixes the thrust body in position until the at least one first actuator once again acts on the thrust body.  
           [0017]    The at least one second actuator must drive the at least one armature ring in only one rotation direction.  
           [0018]    In accordance with yet a further mode of the invention, the at least one armature ring interacts with the thrust body in that the at least one armature ring is rotated alternately in the rotation directions about the longitudinal axis, and for the latching apparatus to cause latching, which, in each case, fixes the thrust body in position until the at least one first actuator acts on the thrust body once again.  
           [0019]    In such a case, one refinement of the method provides for the armature ring to rotate, in the event of any rotary movement, in the opposite direction to its direction of rotation in the previous movement step.  
           [0020]    However, it is also feasible for two or more movement steps first of all to be carried out in one rotation direction, after which two or more movement steps are carried out in the opposite rotation direction. Furthermore, there are, advantageously, no fundamental restrictions relating to the number of movement steps in one rotation direction or the other having to be of equal magnitude.  
           [0021]    The method can be ended in a simple manner when a specific switching-on criterion is reached.  
           [0022]    By way of example, the method is ended on reaching a specific number of movement steps after the start of the method. The overall distance traveled by the thrust body can be determined in a simple manner from the number of movement steps and from the individual movement distances associated with the movement steps.  
           [0023]    A further possible way to end the method is to use a signal for switching-off purposes. Such a signal is, advantageously, generated in a simple manner, for example, by a limit switch when the thrust body reaches a specific position.  
           [0024]    Another alternative signal that is useful for switching-off purposes may be a signal corresponding to an appropriate distance measurement.  
           [0025]    With the objects of the invention in view, there is also provided a driving configuration, including a thrust body, a bidirectional linear solenoid drive for driving the thrust body in steps until the thrust body has reached a respective final position, the solenoid drive having at least one first actuator and at least one second actuator, the first actuator having at least one yoke, at least one solenoid, and at least one armature ring, the first actuator configured to substantially axially move the thrust body, the yoke and the armature ring being separated at a distance from one another to define therebetween an active air gap, the armature ring configured to operatively interact with the thrust body and, thereby, apply force alternately to the thrust body, the second actuator operatively connected to the armature ring to rotate the armature ring and, thereby, axially shift the thrust body and subsequently fix the thrust body in position, and a latching apparatus configured to fix the thrust body at times.  
           [0026]    With the objects of the invention in view, there is also provided a driving configuration, including a thrust body, a bidirectional linear solenoid drive for driving the thrust body according to the method of claim  1 , the solenoid drive having at least one first actuator and at least one second actuator, the first actuator having at least one yoke, at least one solenoid, and at least one armature ring, the first actuator configured to substantially axially move the thrust body, the yoke and the armature ring being separated at a distance from one another to define therebetween an active air gap, the armature ring configured to operatively interact with the thrust body, the second actuator operatively connected to the armature ring to rotate the armature ring, and a latching apparatus configured to fix the thrust body at times.  
           [0027]    According to the invention, a configuration for carrying out the method according to the invention for driving a thrust body by a bidirectional linear solenoid drive is proposed, in which configuration the bidirectional linear solenoid drive has at least in each case one first actuator and one second actuator. The at least one first actuator has at least one yoke, at least one coil, and at least one armature ring and is provided for substantially axial movement of the thrust body. The distance between the at least one yoke and the at least one armature ring is in the form of an active air gap, with the at least one armature ring being provided for interaction with the thrust body. The at least second actuator is provided at least for rotation of the at least one armature ring, and a latching apparatus is provided to fix the thrust body at times.  
           [0028]    The drive energy that is required is provided by an electrical drive with a small number of moving components. This means that the configuration according to the invention operates with little maintenance, robustly and with high reliability, and with correspondingly little susceptibility to malfunctions when changes occur in the environmental conditions.  
           [0029]    In accordance with yet an added feature of the invention, the first actuator has at least two permanent magnets and the permanent magnets magnetically act upon the armature ring to magnetically clamp the armature ring in an unstable manner.  
           [0030]    In accordance with yet an additional feature of the invention, the surface of the thrust body is to be provided with a holding structure at least in places in the area of the surface facing the at least one armature ring to be provided on the surface facing the thrust body with a mating structure that is compatible with the holding structure and is inserted into the holding structure during rotation about the longitudinal axis of the armature ring.  
           [0031]    It is particularly advantageous for the thrust body to have an outline in the form of a cylinder, a plunger, an annulus, and a tube. In particular, the outline is a cylindrical outline. Such an outline assists the rotary movements and simplifies the construction of the armature ring and of its connection to the thrust body.  
           [0032]    A tubular outline is also advantageous for the thrust body because this shape is required particularly frequently in boreholes for conveying raw materials. In such a case, an outer production tube together with a transport tube that is guided therein forms an annular space in which the components that are required in the borehole are accommodated. It is, thus, advantageous for the thrust body to be tubular.  
           [0033]    In accordance with again another feature of the invention, the holding structure has first recesses parallel to the axis. The mating structure can move axially in these first recesses. These first recesses are, advantageously, often in the form of grooves or slots, for manufacturing reasons.  
           [0034]    In addition, the holding structure has second recesses in the axial direction, for example, once again in the form of grooves or slots. The mating structure engages in the second recesses as a result of rotary movement. When a movement step takes place, the entire drive power of the bidirectional linear solenoid drive is transmitted through the mating structure into the holding structure onto the thrust body, or vice-versa.  
           [0035]    In accordance with again a further feature of the invention, the holding structure has substantially helical recesses and the substantially helical recesses permit a combined axial/radial movement of the armature ring. In particular, the first and/or second recesses are grooves, slots, or threads. Further, the substantially helical recesses are grooves, slots, or threads.  
           [0036]    In accordance with again an added feature of the invention, the holding structure and the mating structure are, according to the invention, subject to particular mechanical loads and must be configured accordingly, possibly using different materials to the holding structure or the mating structure.  
           [0037]    It is has been found to be advantageous for the mating structure and the holding structure to be composed of stainless steel.  
           [0038]    In accordance with again an additional feature of the invention, the recesses are one of radially and helically provided on the thrust body and the mating structure is matched to the holding structure to engage in the recesses in the holding structure by a substantially radial movement of the mating structure and/or the holding structure.  
           [0039]    In accordance with still another feature of the invention, the mating structure is configured with one of recesses and grooves running parallel to the longitudinal axis to allow the mating structure to move substantially parallel to the thrust body axis in the holding structure.  
           [0040]    Stainless steel is only slightly magnetic and is, thus, not suitable as a material for the at least one armature ring. A mating structure that is produced from stainless steel is, according to the invention, firmly connected to the at least one armature ring.  
           [0041]    The advantages of the magnetic material and the advantageous mechanical characteristics of stainless steel are, then, combined with one another for this refinement of the at least one armature ring. It is particularly advantageous to use a nut or a reversing nut as the mating structure.  
           [0042]    The mating structure may, however, also be integrally formed on the at least one armature ring.  
           [0043]    In accordance with still a further feature of the invention, the holding structure and the mating structure are provided radially between the armature ring and the thrust body.  
           [0044]    In accordance with still an added feature of the invention, the holding structure and the mating structure are at least partially provided away from a section of the longitudinal axis of the armature ring.  
           [0045]    The location of the point at which the holding structure and the mating structure engage with one another is only of secondary importance according to the invention. Depending on given spatial conditions, for example, this point may be provided at least partially away from the section of the longitudinal axis on which the at least one armature ring is provided.  
           [0046]    Because the requirements mean that particularly high drive forces have to be applied, the number of first actuators can, advantageously, be increased. The armature rings are, then, disposed such that they jointly transmit forces to the thrust body, or absorb forces from it. There is, therefore, no need to change the type of first actuator. This, advantageously, takes account of the availability of only a restricted space or annular space for the drive. All that is necessary is to match the number of first actuators to the drive requirement. This, advantageously, means that there is no restriction to the maximum thrust force produced by the first actuators.  
           [0047]    This also allows redundancies to be completed in a particularly simple manner.  
           [0048]    If, for example, for safety reasons, mechanical redundancy is required, the number of first actuators required is, first of all, simply chosen. Redundancy is, accordingly, provided if the chosen number of first actuators is chosen to be at least one greater than is necessary by virtue of the design. The redundancy is increased in a corresponding manner if the number of first actuators is increased further.  
           [0049]    In accordance with still an additional feature of the invention, the first actuator is at least two first actuators each having an armature ring and being disposed to one of jointly transmit forces to the thrust body and absorb forces from the thrust body.  
           [0050]    If electrical redundancy is required, the number of first actuators must, likewise, be increased above the number required by virtue of the design, and this can easily be done in the same way.  
           [0051]    In accordance with another feature of the invention, mechanical and electrical redundancy can, advantageously, be achieved easily by the same procedure as for the first actuators for the second actuators for the radial drive for the components, as well.  
           [0052]    In accordance with a further feature of the invention, the solenoid drive, the second actuator, the thrust body, and the latching apparatus are to be disposed in an annular space between an outer tube and an inner tube.  
           [0053]    In accordance with an added feature of the invention, the latching apparatus is mechanically coupled to the rotary movement of the at least one armature ring. The coupling is provided, for example, mechanically to at least one armature ring or to the at least one second actuator. The latching apparatus follows rotary movements of the armature ring or second actuator in a corresponding manner or utilizes rotary movement of the armature ring or second actuator as a drive.  
           [0054]    When the at least one armature ring then rotates, for example, with the mating structure into the holding structure, the latching apparatus advantageously rotates with it automatically to a position in which the thrust body can move axially. If the mating structure, then, once again rotates out of the holding structure, the latching apparatus likewise moves with it and moves to a different position in which axial movement or resetting of the thrust body is prevented.  
           [0055]    A further possibility is to provide a dedicated drive for the latching apparatus by at least one third actuator. This necessarily results in there being at least three actuators or drives, overall.  
           [0056]    It is also feasible for all of the actuators to be provided in a redundant form, that is to say, for example, by equipping the latching apparatus with redundant second actuators and by equipping the at least one armature ring with redundant first actuators.  
           [0057]    In accordance with an additional feature of the invention, the position of the thrust body can, advantageously, also be visualized by a display. The signals that are produced by such a display are generated by a step counter, a movement sensor, or other signal transmitters, which are suitable for measuring, for determining or for calculating positions.  
           [0058]    In accordance with yet another feature of the invention, there is provided at least one step counter measuring individual forward and backward steps of the thrust body and indicating a position of the thrust body from the measurement.  
           [0059]    In accordance with yet a further feature of the invention, there is provided a linear movement sensor measuring the thrust body and indicating a position of the thrust body from the measurement.  
           [0060]    In accordance with yet an added feature of the invention, there are provided a limit switch operatively connected to the thrust body, a linear movement sensor measuring the thrust body and indicating a position of the thrust body from the measurement, and at least one of the step counter, the linear movement sensor, and the limit switch producing a signal from which axial movement of the thrust body ends.  
           [0061]    In accordance with yet an additional feature of the invention, there is provided one or more power supply units for supplying electrical power to electrical load(s).  
           [0062]    Because the bidirectional linear solenoid drive is also used, in particular, in extreme environmental conditions, the first, second, and, possibly, the third actuators are, advantageously, configured to be encapsulated in such a situation.  
           [0063]    The encapsulation prevents the ingress of dirt or other foreign substances, which could possibly have a negative influence on the operation of the configuration.  
           [0064]    If the bidirectional linear solenoid drive is operated in a high environmental pressure in corrosive or contaminated media, it has been found, according to the invention, to be expedient to use a moving sealing wall for encapsulation. The pressure difference between the encapsulated area and the environment can, therefore, be compensated for by movement of a virtually rigid wall, or by expansion of a sealing wall that is flexible or can expand, in particular, until pressure equalization is achieved between an interior of the encapsulation and the environment. The configuration avoids the ingress of dirt particles or of a corrosive medium into the bidirectional linear solenoid drive.  
           [0065]    If the sealing wall is virtually rigid and inflexible, it can be configured to be moved, for example, parallel to the axis, and possibly to be guided, on a sliding surface. It has, then, been found to be useful to fit a sliding seal between the moving sealing wall and the sliding surface to prevent the ingress of dirt into the encapsulated area, but, at the same time, to allow the movement of the sealing wall.  
           [0066]    If the environmental pressure rises, a correspondingly greater amount of pressure equalization must be carried out, with a correspondingly greater equalization volume.  
           [0067]    In accordance with again another feature of the invention, there is provided a sliding seal disposed between the sealing wall and the first actuator, the second actuator, and/or the thrust body and creating a seal therebetween.  
           [0068]    The expansion or the necessary movements of the sealing wall is or are particularly small when, according to the invention, the encapsulation (that is to say, the complete encapsulated area) is filled with a liquid medium.  
           [0069]    In accordance with again a further feature of the invention, a high-temperature-resistant oil (up to 225° C.) is, advantageously, inserted into the encapsulation because, in addition to the pressure, it also has to withstand the high temperatures that often occur.  
           [0070]    The permanent magnets that are used in the actuators, in particular, in the at least first actuators, are, preferably, composed of hard-magnetic material, in order to produce a hysteresis loop that is as broad as possible. AlNiCo can be used, in particular, as a hard-magnetic material.  
           [0071]    For configurations that are used in extreme environmental conditions, in particular, in high ambient temperatures, the Curie temperature of the hard-magnetic materials that are used has values that are higher than 600° C. to avoid demagnetization or an excessively short life.  
           [0072]    In contrast, the at least one armature ring and the yoke of the first actuators, in particular, are manufactured from soft-magnetic materials, in particular, including RNi12. These materials prevent remagnetization losses and achieve an advantageously high degree of saturation induction.  
           [0073]    According to the invention, there are a number of possible ways to supply electrical power to the drives.  
           [0074]    A particularly compact form for the electrical power supply is achieved by supplying existing drives with electrical power from a power supply unit.  
           [0075]    It is feasible for the invention to provide two or more power supply units. One power supply unit then, for example, supplies the at least one first actuator, and the further power supply unit supplies the at least one second actuator for the rotary movement, and so on.  
           [0076]    In accordance with again an added feature of the invention, every first, second or, third actuator is provided with a power supply unit that is associated solely with it. Such a configuration improves the reliability of the electrical power supply, thus reducing the failure probability.  
           [0077]    Redundancy is also worthwhile for the power supply units. Accordingly, at least one more power supply unit is provided than is necessary for the electrical construction. If one power supply unit now fails, even temporarily, for example, as a result of overheating, a control device can switch to the redundant power supply unit. Such a configuration ensures continued operation without any interruptions.  
           [0078]    If the aim is to achieve particularly protected operation or particularly high availability, correspondingly more power supply units are added to the configuration, for example, until every actuator is equipped with two power supply units.  
           [0079]    In accordance with again an additional feature of the invention, the control device can coordinate all the movement sequences of the actuators and components in the configuration. An advantageous configuration of the control device is also provided when signals are generated or processed, and calculations are carried out by it.  
           [0080]    In accordance with still another feature of the invention, the solenoid drive has a first axial face, a second axial face, and an axial extent with a first supply area disposed over an entirety of the axial extent and through which lines are to be passed from the first axial face to the second axial face.  
           [0081]    In accordance with still a further feature of the invention, the first supply area is a recess in the solenoid drive and is shaped as a part of a hollow cylinder.  
           [0082]    In accordance with a concomitant feature of the invention, the inner tube is guided eccentrically in the outer tube at least in an area of the solenoid drive, the solenoid drive has an external diameter, a first axial face, and a second axial face, a second supply area is provided between the external diameter of the solenoid drive and an internal diameter of the outer tube, and lines are to be passed through the second supply area from the first axial face to the second axial face.  
           [0083]    Other features that are considered as characteristic for the invention are set forth in the appended claims.  
           [0084]    Although the invention is illustrated and described herein as embodied in a method and configuration for driving a thrust body by a bidirectional linear solenoid drive, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.  
           [0085]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0086]    [0086]FIG. 1 is a fragmentary, cross-sectional view of an area around an air gap according to the invention;  
         [0087]    [0087]FIG. 2 is a fragmentary, cross-sectional view through a configuration of first actuators according to the invention;  
         [0088]    [0088]FIG. 3 is a cross-sectional view of a first actuator of FIG. 2 along section line A-A;  
         [0089]    [0089]FIG. 4 is a perspective view of one refinement of a configuration according to the invention;  
         [0090]    [0090]FIGS. 5A to  5 F are diagrammatic, cross-sectional views of a mating structure of a structure element and a holding structure of a transport tube according to the invention in various steps in the method according to the invention;  
         [0091]    [0091]FIG. 6 is a fragmentary, perspective view of a solenoid drive for a latching element according to the invention; and  
         [0092]    [0092]FIG. 7 is a fragmentary, cross-sectional view through an exemplary embodiment of a configuration according to the invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0093]    Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a section through an area around an air gap  24  between a yoke  20  and an armature  22  in an air gap area  10  in a bidirectional solenoid drive. The armature  22  and the yoke  20  have the material thickness  26 , to be precise in the direction of their extent between the correspondingly associated upper faces  28  and  30 , respectively, and their lower faces  32  and  34 , respectively. The flat side surfaces, which can be seen in FIG. 1 as side lines, of the yoke  20  and of the armature  22  that are opposite one another are separated by the constant distance  36  and are at an angle α to the perpendicular to the upper faces  28 ,  30 . The side lines of the mutually opposite side surfaces have a length  40 , which is greater by the factor of the reciprocal of the cosine of the angle a than the material thickness  26  of the yoke  20  or of the armature  22 . The maximum travel  42  in the direction of the spatial position of the upper faces  28 ,  30  is obtained from the constant distance  36 , multiplied by the factor of the reciprocal of the cosine of the angle α, between the mutually opposite side surfaces.  
         [0094]    [0094]FIG. 1 thus shows that position of the yoke  20  and of the armature  22  with respect to one another in which they are at the maximum distance from one another. As the maximum travel  42  increases, the magnetic force acting between the yoke  20  and the armature  22  decreases. However, the magnetic force affect can be at least partially compensated for again by suitable choice of the angle a. For maximum travels  42  of under 2 mm, the force maximum occurs at an angle α of 0°, or close to this value. If the maximum travel  42  is chosen to have a greater value than 2 mm, the particularly advantageous value of the angle α rises to 45°, and possibly to even higher values.  
         [0095]    [0095]FIG. 2 shows a longitudinal cross-section through four first actuators  11 ,  12 ,  13 ,  14  for a bidirectional solenoid drive, which are disposed in an annular space between an outer tube  44 , for example, a borehole tube, and an inner tube  46 , for example, a production tube.  
         [0096]    The cross-section shows the axis of symmetry of the rotationally symmetrical configuration as a line of symmetry  48  in the longitudinal section. The inner tube  46  has an external diameter  50 . The unobstructed width of a transport tube  52  is actually chosen to be somewhat larger than the external diameter  50 , and its surface, which faces the inner tube  46 , that is to say, the inside, is smooth so that it can move guided on and over the inner tube  46 . The outside of the transport tube  52  has a holding structure  54  that has transverse grooves  56  with a rectangular profile in the radial direction, as well as longitudinal grooves in the axial direction, although these are not illustrated. In the area of the further actuators  11 ,  12 ,  13 ,  14 , a mating structure element  58  engages in the holding structure of the transport tube  52 . The section in FIG. 2 shows that the contours of the mating structure element  58  facing the transport tube are precisely matched to the holding structure  54  so that the transverse grooves  56  are completely filled with the mating structure element  58  in this area. The structure element  58  is substantially a tubular section whose surface facing the holding structure  54  is contoured as described, is smooth on its outer face, and is connected to each of the armature rings  62  of the first actuators  11 ,  12 ,  13 ,  14 . The armature rings  62  of the first actuators  11 ,  12 ,  13 ,  14  are, thus, in the end connected to one another with a force fit by the mating structure element  58 , and, in this way, form a common, effective, overall armature ring. As can easily be seen, instead of the overall armature ring that is formed of the armature rings  62  and with the mating structure  58 , it is also possible for an overall armature ring such as this to be in the form of a single element.  
         [0097]    All four first actuators  11 ,  12 ,  13 ,  14  are constructed identically and are disposed such that they rest tightly against one another, completely filling the available annular space between the outer tube  44  and the transport tube  52 . The first actuators  11 ,  12 ,  13 ,  14  are accordingly constructed to be annular, concentric and symmetrical with respect to a line of symmetry  48 .  
         [0098]    One major element of a first actuator  11 ,  12 ,  13 ,  14  is a yoke ring  60  that is in the form of a hollow body, thus, in this way, forming the outer sleeve of the first actuator  11 ,  12 ,  13  or  14 . To this extent, the further yoke  60  also forms the side boundary between the interior of the first actuator  11 ,  12 ,  13  or  14  and the surrounding annular space. The further yoke ring  60  is chamfered at an angle of approximately 45° towards the center of the inner face of the first actuator  11 ,  12 ,  13  or  14  on both side parts, which point in the axial direction, on the side pointing towards the transport tube  52 . This chamfer starts at a distance of about a quarter of the annular space height from the internal diameter of the first actuator  11 ,  12 ,  13  or  14 . The outer sleeve that is formed by the further yoke ring  60  is open at only one point, namely, on the surface facing the transport tube  52 . An opening that is annular by virtue of the geometry and is bounded by the chamfered flanks of the yoke ring side areas is formed in this surface. The armature ring  62  of the first actuator  11 ,  12 ,  13  or  14  is fitted in an annular shape into this opening. There is a small gap  64 ,  65  between the armature ring  62  and each of the flanks of the yoke ring  60 . These gaps  64 ,  65  allow the armature ring  62  to move in the axial direction, and the extended length between the armature ring  62  and the yoke ring  60  in the axial direction determines the maximum movement step that can be carried out by the first actuator  11 ,  12 ,  13  or  14 . The armature ring  62  is symmetrical with respect to an imaginary plane of symmetry that, in the axial direction, runs precisely centrally in the respective first actuator  11 ,  12 ,  13  or  14  and is at right angles to the line of symmetry  48 . On its side facing the transport tube  52 , the armature ring  62  has two moldings  66 ,  67 , which are approximately in the form of a 90° bend and are disposed such that one limb of the molding lies in the plane of symmetry and the other limb, which ends with a flat end surface, projects at right angles out of the plane of symmetry.  
         [0099]    A permanent magnet ring  68 ,  69 , which is virtually square in shape in the section shown in FIG. 1, is in each case located between an end surface and the respective side wall of the corresponding half of the yoke ring  60 .  
         [0100]    Four coils or solenoids  72 ,  73 ,  74 ,  75  that are identical are located in the cavity in the yoke ring  60  between the area having the largest diameter and the permanent magnet  68 ,  69  and occupy the entire available intermediate space in the cavity in the axial direction, rest internally on the face with the larger diameter on the inside of the yoke ring  60 , and are at a specific distance from the boundary surface of the permanent magnet at the point where the diameter is a maximum.  
         [0101]    [0101]FIG. 3 shows a view of a section of the plane A-A through the first actuator  13 . The position of the plane A-A can be seen in FIG. 2. All the illustrated components are disposed around a common center point  80 , the intersection of the line of symmetry  48  with the section plane A-A. The individual components in this view can substantially be seen as annular surfaces between the inner tube  46  and the outer tube  44 . The width of the individual annular surfaces is chosen to correspond to the configuration of the components shown in FIG. 2.  
         [0102]    The section through the outer tube  44  is illustrated as the outermost, first ring. Disposed in sequence from the inside to the outside are the annular surfaces of the yoke ring  60 , of the solenoid  72 , of a first annular gap  82 , of the permanent magnet ring  68 , of a second annular gap  84 , of the yoke ring  60  once again, of the transport tube  52  and of the inner tube  46 .  
         [0103]    [0103]FIG. 4 shows a three-dimensional view of one refinement of a configuration according to the invention. This exemplary embodiment of the configuration is intended for use as an oil source and drives a restrictor valve  90  that limits the flow of oil through a production tube  92 , which is illustrated only in the area of the configuration and of the restrictor valve  90 . This symbolizes that the production tube  92  continues from both ends of the illustrated tube section, that is to say, on one hand, in the direction of the feed flow to the feed device for the oil source, for example, the oil platform, and, at the other end, in the direction of a further oil source. The production tube  92  is provided at its end in the direction of the oil source with square recesses  94 , which are distributed over the entire circumference of the outer surface of the production tube  92 . The recesses  94  are disposed in rows along the axis of symmetry of the production tube  94  and also project into the area of the restrictor valve so that some of the recesses  94  are concealed, and some of the recesses  94  are covered in the area of the end of the restrictor valve. As such, recesses  94  that are not closed allow a specific amount of oil to flow from the environment through the recesses  94  into the interior of the production tube  92 .  
         [0104]    The restrictor valve  90  substantially has a piece of tubing  96  that is disposed such that it can be moved over the production tube  92 . The piece of tubing  96  has an unobstructed width that precisely fits over the production tube  92 . This, on one hand, allows the piece of tubing  96  to be moved parallel to the axis, but, on the other hand, prevents oil from flowing through the recesses  94  that are covered by the piece of tubing  96 . The piece of tubing  96  is chosen to be at least sufficiently long that, when the restrictor valve  90  is in the completely closed position, the piece of tubing  96  covers all of the recesses  94  and prevents any oil flow through the recesses  94 .  
         [0105]    The piece of tubing  96  is connected to a tubular thrust body  100  by two connecting elements  98 , one of which is visible. Any axial movement of the thrust body  100  is transmitted mechanically through the connecting elements  98  to the piece of tubing for the restrictor valve  90 . Six holding structure elements  102  are distributed uniformly over the circumference of the thrust body  100 , two of which can be seen in this view. The holding structure elements  102  are fitted to the outer surface of the thrust body  100 , have a width corresponding to above 20 degrees of the circumference of the thrust body  100 , are parallel to the axis of symmetry of the thrust body, and start and end at a distance from the thrust body ends that corresponds approximately to twice the extent of their width. The view of the configuration also shows a latching sleeve tube of a catch  104  as well as a sleeve tube  106  for the first actuators  11  etc., which are configured to be tubular as an outer housing, have the same external diameter, and are joined to one another by inserting a sealing element  108  between them. The same external diameters are matched in a corresponding manner to a borehole tube, which is not illustrated.  
         [0106]    The catch  104  as well as its at least one second actuator are provided as a drive in the annular space between the latching sleeve tube and the thrust body  100 , with the catch  104  being located on that side of the thrust body  100  that faces away from the restrictor valve  90 . The thrust body  100  projects by an amount approximately equal to the magnitude of its external diameter longer than the sum of lengths of the catch sleeve tube and sleeve tube  106  and is disposed approximately centrally around the catch  104  and the first actuators of the bidirectional linear solenoid drive so that the thrust body  100  overhangs the two end surfaces of the overall body including the catch  104  and the first actuators.  
         [0107]    A power supply  117  can supply electrical power to the thrust body  100  and a control device  119  can control at least the power supply  117 . It is noted that the sleeve tube  106  can have an encapsulation protecting it against environmental conditions.  45 . The solenoid drive has an axial extent with a first supply area disposed over an entirety of the axial extent and through which lines  121  are to be passed from the first axial face to the second axial face. The inner tube can be guided eccentrically in the outer tube at least in an area of the solenoid drive. A second supply area can provided between an external diameter of the solenoid drive and an internal diameter of the outer tube and the lines  121  are to be passed through the second supply area from the first axial face to the second axial face.  
         [0108]    [0108]FIGS. 5A to  5 F, which now follow, show sketches that correspond to various steps in the method according to the invention. In a simplified illustration, they show in a planar development the section through the mating structure of the structure element  58  and through the holding structure  54  of the transport tube  52 . Crossing axes are shown on the sketches, for illustrative purposes. These Cartesian coordinate axes are aligned such that a vector to the right points in the x-axis direction, corresponding to the radial direction, and a vector upwards points in the y-axis direction, corresponding to the axial direction.  
         [0109]    In all of the sketches, the transport tube  52  has first recesses  110  in the x-axis direction and second recesses  112  in the y-axis direction on its outer surface. The webs  114  that are formed by the first and second recesses  110 ,  112  together produce the holding structure  54 . The second recesses  112  are disposed parallel to the center axis of the transport tube  52  and have the first width  116 . The second width  118 , which is governed by the second recesses  112 , is subdivided uniformly by the first recesses  110  so that webs  114  have a shape in the form of ribs, with the first recesses  110  having a fifth width  130  between two adjacent webs  114 , with this fifth width  130  being slightly greater than the web thickness  122  of the webs  114 . A rib-like web  114  with web thickness  122  could, thus, just be moved in the x-direction into a first recess  110  whose width is  130 .  
         [0110]    The example of FIGS. 5A to  5 F shows two, and only two, web rows, each having eight such rib-like webs  114 . Each of the rib-like webs  114  has rounded edges, in this view the corners of the webs  114 . The first width  116  of the second recesses  112  is slightly greater than the second width  118  of the webs  114 . An object with the second width  118  can, thus, just move in the y-direction in a second recess  112 .  
         [0111]    The structure element  58  of the armature ring  62  is configured to be identical to its mating structure, with the same dimensions as the elements of the holding structure  54  of the transport tube  52 , and with two longitudinal grooves  124 ,  125  having the fourth width  126  in the y-direction, which fourth width  126  corresponds to the first width  116 , and with the structure element webs  128  having the fifth width  130 , corresponding to the second width  118 , and with the structure element webs  128  having the structure element web thickness  132  corresponding to the web thickness  122 , and with a transverse groove  136  having a sixth width  134  that, in a corresponding manner, is the same as the third width  120 . Each web row represents eight webs  114  and structure element webs  128 . In order to make it easier to distinguish between the webs  114  and the structure element webs  128 , the section surfaces of the structure element webs  128  are illustrated in a homogeneously dark form.  
         [0112]    [0112]FIG. 5A represents an initial position to describe the method of the present invention. The illustration of the structure element  58  starts at the origin of the coordinate system, such that a row of structure element webs  128  with their respective left-hand boundaries touches the y-axis, and the lowermost of the structure element webs  128  with its lower boundary just touches the x-axis, with the longer faces of the structure element webs  128  being parallel to the x-axis.  
         [0113]    That row of webs  114  that is closer to the y-axis is disposed centrally in the longitudinal groove  124  between the two rows of structure element webs  128 . The webs  114  and the structure element  128  are offset with respect to one another in the y-direction such that the structure element webs  128  are precisely at the same level as the first recesses  110 . Those two webs  114  that are closest to the x-axis start with an offset precisely equal to the distance of a third width  120  from the x-axis in the positive y-direction.  
         [0114]    According to the invention, the armature ring and, thus, the mating structure are rotated through a specific angle, for example, through 5°, about its axis. This direction will be regarded as the positive rotation direction. In the illustrated development view, this rotation corresponds to a shift of the mating structure of the armature ring through a specific amount in the positive x-axis direction, that is to say, the radial direction.  
         [0115]    [0115]FIG. 5B shows the result of the described movement, which is illustrated as a first movement arrow  138 . The structure element webs  128  are completely engaged between the webs  114 , that is to say, in each case in one, and in only one, of the first recesses  110 . Only those two structure element webs  128  that are closest to the x-axis are not adjacent to any web  114  on their side that faces the x-axis. The configuration according to the invention results in a type of tooth system, in which, in this position, the structure element  58  and the holding structure  54  engage in one another such that axial forces, that is to say, forces that act in the y-axis direction, are transmitted from the structure element  58  to the holding structure, or vice-versa. The longitudinal grooves  124 ,  125  are completely free of webs  114 .  
         [0116]    The structure element  58  is now moved in accordance with the method according to the invention by the bidirectional linear solenoid drive through a movement step in the y-axis direction. Thus, in consequence, the thrust body, the transport tube  52  in the example here, is also moved in the direction of the y-axis.  
         [0117]    [0117]FIG. 5C shows the position of the structure element  58  and holding structure  54  after this movement step, which is illustrated as a second movement arrow  140 . The structure element  58  has been moved by the sum of the third width  120  and of the web thickness  122 . The holding structure  54 , which is engaged with the structure element  58 , has, accordingly, likewise been moved through the same distance. The distance between the x-axis and the lowermost of the webs  114  has, thus, also been increased in a corresponding manner.  
         [0118]    According to the method, the axial position reached by the holding structure  54  is now secured by at least one catch, which may also be understood as meaning a blocking apparatus, a bolt, or a similar apparatus that in any case prevents, the position being left in the y-direction, once it has been reached, and that is, thus, connected to the holding structure  54  or to the thrust body, that is to say, in the chosen example to the transport tube  52 , such that the forces that would reset the holding structure  54  to the initial position are passed on to the catch. The catch can, for example, pass on these forces that have been introduced to the outer tube  44  and/or to the inner tube  46  and can, thus, so to speak, be supported there. The catch or blocking apparatus is, however, not shown in this figure.  
         [0119]    The holding structure  54 , thus, dissipates any restoring forces that may be present through the catch, and cannot be moved back to the previous position.  
         [0120]    In the method step that now follows, the structure element  58  is rotated back through the specific angle, that is to say, for example, through 5°, in the negative rotation direction.  
         [0121]    [0121]FIG. 5D shows the position of the webs  114  and of the structure element webs  128  after being rotated back in this way, as is illustrated by the third movement arrow  142 . The mating structure is moved back precisely to its initial position in the direction of the x-axis, that is to say, the outermost left-hand edges of the structure element webs  128  in the left-hand row just touch the y-axis. The position of the structure element webs  128  in the y-direction is as shown in FIG. 5C.  
         [0122]    Overall, the structure element  58  is, once again, located in the longitudinal grooves in the holding structure  54  and is, thus, free to move in the direction of the longitudinal groove, that is to say, in the y-direction.  
         [0123]    The position of the holding structure  54  is unchanged, as is described in FIG. 5C.  
         [0124]    Because the structure element  58  and the holding structure  54  have now released their engagement in one another again, the structure element is moved downwards by the armature ring of the bidirectional linear solenoid drive in the longitudinal grooves of the holding structure  54 , that is to say, in the negative y-direction, until its original position as shown in FIG. 5-A is reached.  
         [0125]    [0125]FIG. 5E shows the position of the structure element  58  and of the holding structure  54 , with the method step that has just been described being indicated by a fourth movement arrow  144 . The structure element  58  is in its original position, as described in FIG. 5A, and is, thus, once again in the position in which the method can start once again with its first method step. In comparison to the position described in FIG. 5A, the holding structure  54  has been shifted by a distance precisely equal to the web thickness  122  plus a third width  120  in the positive y-axis direction in comparison to its original position as shown in FIG. 5A. This amount corresponds precisely to the length of a movement step of the bidirectional linear solenoid drive. The structure element webs  128  and the webs  114  are, accordingly, once again offset with respect to one another such that the webs  114  are located precisely at the same level as the transverse grooves  136 .  
         [0126]    According to the invention, the rotary movement through the specific angle can, now, once again take place. In accordance with the method, the structure element  58  rotates into the holding structure  54 . Both structures are, thus, once again engaged with one another.  
         [0127]    [0127]FIG. 5F indicates the position of the structure element  58  and of the holding structure  54  after the movement step that has just been described, and that is indicated by a fifth movement arrow  146 . The sketch is, thus, substantially the same as that in FIG. 5B, but with the difference that the holding structure  54  is offset upwards, in the y-axis direction, by the length of one movement step.  
         [0128]    When all of the process steps in the method are carried out, the holding structure  54  and, thus, the thrust body is moved forwards by precisely one movement step in the y-axis direction, until, for example, a predetermined number of cycles of the method have been carried out and the thrust body has, thus, been shifted by precisely the length that corresponds to the distance covered by the specific number of movement steps. For example, a step counter  111  counts each cycle of the method and ends the forward movement once a predetermined number of steps or cycles has been reached. The step counter  111  detects real rotating movements, e.g., optically or mechanically. Also, a linear movement sensor  113  can be provided to measure the thrust body and indicate a position of the thrust body from the measurement. A limit switch  115  can be operatively connected to the thrust body. The step counter  111 , the linear movement sensor  113 , and/or the limit switch  115  produces a signal from which axial movement of the thrust body ends.  
         [0129]    [0129]FIG. 6 shows a three-dimensional view of a second actuator of a latching element  150 , obliquely into a circular tube section end  154  of an outer tube section  152 , with the latter bounding the latching element  150  in its radial extent as a sheath. Six supporting elements  156  of-an external support are distributed uniformly over the circumference of the tube section end  150  at the visible tube section end  154 . These supporting elements  156  have a width of approximately 20° of the circular arc, and their external radius is bounded by the unobstructed diameter of the outer tube section  152  and they are located at about half of their length, that is to say, their extent in the axial direction of the outer tube section  152 , within the outer tube section  152 . The other half projects beyond the imaginary end surface of the outer tube section  152 . Recesses are fitted approximately centrally in the side parts of the supporting elements  156 , and are disposed such that an annular magnet core  158  passes through each of the recesses so that the supporting elements  156  are distributed uniformly on the magnet core  158 . A solenoid  160  that is in the form of a tubular arc is disposed in the space between in each case two adjacent supporting elements  156  on the sub-area that is provided there of the magnet core  158  and, in this view, its left-hand side touches the right-hand side of the adjacent supporting element  156  and extends up to a distance of approximately 5° of the circular arc on the left-hand one of the adjacent supporting elements. The coils that together with the magnet core  158  form a magnetic drive can move with the supporting elements  156  that are located on the magnetic core  158  through precisely these 5°.  
         [0130]    The supporting elements  156 , furthermore, each have an outer supporting surface  162 , which is planar, starts on the outer radial area of the supporting element  156 , and is disposed on the side facing away from the outer tube section  152 . An inner supporting surface  164 , which is planar and makes contact with the end surface of a nut  166 , is in each case disposed on that side of the supporting elements  156  that faces the outer tube section  152 , in order to, in fact, be located in the interior of the outer tube section  152  as a result of its position. The nut  166  has an internal thread that has longitudinal grooves that run parallel to the axial direction of the outer tube section  152 , thus making it possible to screw in a thrust body there or, else, to use this latching element  150  for carrying out the method according to the invention.  
         [0131]    [0131]FIG. 7 shows the view of a longitudinal section through an example of a configuration  168  of a bidirectional solenoid drive according to the invention. This view shows a line of symmetry  170 , which subdivides this view into two halves, one half of which is shown completely. Starting from the line of symmetry  170 , a threaded tube  174  with a first length  176  is disposed around a tube  172 . Starting at a distance of about half the radius of the threaded tube  174  from its edges, the threaded tube  174  has a surface structure  178  that has recesses that run in the direction parallel to the line of symmetry  170  and are illustrated, as well as recesses that are in the form of threads, but are not illustrated for the sake of clarity.  
         [0132]    A drive  180  according to the invention is disposed around the threaded tube  174 , substantially being disposed in the form of a circumferential annular space between a tubular, outer housing  182  and the threaded tube  174 . The drive  180  is configured to be symmetrical, when seen from the end surfaces of the outer housing  182 . When seen from the end surface  184 , the annular gap between the outer housing  182  and the threaded tube  174  is virtually completely closed by an annular cover  186 . A supporting ring  188  is disposed at the contact point between the cover  186  and the outer housing  182 .  
         [0133]    The symmetrically disposed second support ring on the other side of symmetry of the drive  180  is in the form of a clamping ring, to clamp together the components that are located between the two supporting rings.  
         [0134]    A connecting element  190  is disposed such that it touches the supporting ring  188  and, in this view, is substantially U-shaped, with the open side facing the threaded tube  174 . A blocking element  192  is disposed on the inner face of that limb of the connecting element that faces the supporting ring and acts as a catch for one movement direction of the threaded tube  174 , for example, as a non-return stop. The symmetrical second blocking element is provided as a catch for the opposite movement direction of the tube  174  accordingly as a block against forward movement in this example.  
         [0135]    The construction of the blocking element  192  and of the second blocking element substantially corresponds to the solenoid  160  on the magnet core  158  shown in FIG. 6.  
         [0136]    An actuator component  194  is adjacent to the outside of that limb of the connecting element  190  that faces away from the supporting ring  188 . Based on knowledge of the fundamental configuration of the actuator  11  as shown in FIG. 2, its individual elements can be seen in functional terms once again in the actuator component  194 . A coil or solenoid element  196  corresponds to one of the solenoids  72  to  75 , a permanent magnet element  198  corresponds to a permanent magnet ring  68  or  69 , an armature element  200  corresponds to the armature ring  62 , and a yoke element  202  corresponds to the yoke ring  60 .