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Title:
CONVERTER FOR CONVERTING ELECTRICAL SIGNALS INTO FLUID SIGNALS
United States Patent 3774644
Abstract:
A converter for converting electrical signals into fluid signals has a permanent magnet and a pair of soft iron pole pieces to form an air gap. Three soft iron plates are integrated with the soft iron pole pieces to complete the magnetic circuit of the permanent magnet. Each plate is provided with rectangular extensions for mating with the soft iron pole pieces, and an armature portion having a fixed end and an opposite free movable end. A coil is wound upon the armature portion for receiving electrical signals and modifying the strength and direction of the magnetic field created by the permanent magnet for urging the free end to move in one or another direction from the neutral position. A fluid passage extending along the axis of symmetry of the armature injects liquid passing therethrough under a supply pressure to a pair of receiving nozzles symmetrically oriented about said axis of symmetry for receiving more or less fluid from said armature in dependence on the position of the latter.


Inventors:
Leutner, Volkmar (Hemmingen, DT)
Romes, Roman (Friolzheim, DT)
Application Number:
05/238149
Publication Date:
11/27/1973
Filing Date:
03/27/1972
Assignee:
Robert, Bosch G. M. B. H. (Stuttgart, DT)
Primary Class:
Other Classes:
137/83, 137/833
International Classes:
F15C1/04; (IPC1-7): F15C3/10
Field of Search:
137/81.5,83,827,831,833 251
View Patent Images:
US Patent References:
3678951METHOD AND APPARATUS FOR IMPROVED JET PIPE VALVESeptember 1972Coakley
3542051FREE JET STREAM DEFLECTOR SERVOVALVENovember 1970McFadden
3452773LAMINATED VALVE STRUCTUREJanuary 1969Denker
3390613Electrohydraulic actuatorsJuly 1968Westbury et al.
3282283Hydraulic regulating system and apparatusNovember 1966Takeda
Primary Examiner:
Cline, William R.
Claims:
What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims

1. A transducer for converting electrical signals into pressure-fluid signals, comprising, in combination, first means defining two receptor conduits having respective outlet ports connectable to a fluid-controlled device and having respective inlet ports located adjacent each other, and including a plurality of firmly joined laminated flat members forming a unitary bendable conduit having one end provided with an inlet connectable to a source of pressure fluid and having an other end provided with an outlet and having an internal flow path extending from said outlet, said bendable conduit being mounted at said one end with such an orientation that the outlet of said bendable conduit is located in the vicinity of said inlet ports but spaced from the latter to establish a branched path for the flow of fluid from the outlet of said bendable conduit simultaneously into both of said inlet ports; and electromagnetic means operative when energized for causing said bendable conduit to bend in dependence upon the energization of said electromagnetic second means in a direction and to an extent moving the outlet of said conduit towards one of said inlet ports and away from the other of said inlet ports to increase the fluid flow into the former and decrease the fluid flow into the latter to establish a difference in the presence of fluid in the two receptor conduits indicative of the energization of said electromagnetic second means.

2. A transducer as defined in claim 1, wherein said plurality of firmly joined laminated flat members includes at least one flat member comprising a portion having a cut-out defining at least a part of said internal flow path and comprising a further portion having another cut-out defining at least a part of one of said receptor conduits.

3. A transducer as defined in claim 1, wherein said plurality of firmly joined laminated flat members includes at least one flat member comprising a portion having a cut-out defining at least a part of said internal flow path and comprising a further portion having another cut-out defining at least part of both said receptor conduits.

4. A transducer as defined in claim 1, wherein said plurality of firmly joined laminated flat members includes at least one flat member having one cut-out defining at least a part of said internal flow path and also at least a part of one of said receptor conduits.

5. A transducer as defined in claim 1, wherein said plurality of firmly joined laminated flat members includes at least one flat member having one cut-out defining at least a part of said internal flow path and also at least part of both said receptor conduits.

6. A transducer as defined in claim 5, wherein said plurality of firmly joined laminated flat members includes two further flat members located at opposite sides of said first flat member and each having a surface portion overlying said cut-out of said one flat member and forming a wall of said internal flow path and a wall of each of said receptor conduits.

7. A transducer as defined in claim 5, wherein said outlet of said bendable conduit is of nozzle-shaped configuration, and wherein the inlet portion of each of said two receptor conduits is configurated as a difussor.

8. A transducer as defined in claim 1, wherein said plurality of firmly joined laminated flat members together form a unitary laminated structure defining both said internal flow path and also said two receptor conduits.

9. A transducer as defined in claim 8, wherein all the flat members of said plurality of firmly joined flat members have outer peripheries of identical configuration.

10. A transducer as defined in claim 8, wherein said plurality of firmly joined flat members is composed of flat members located in different parallel layers with each of said parallel layers containing only a single flat member.

11. A transducer as defined in claim 8, wherein said electromagnetic second means comprises electromagnet coils means encircling said bendable conduit.

12. A transducer as defined in claim 11, wherein said unitary laminated structure includes four generally rectangular projections two of which are located at one axial side of said coil means at either side of said bendable conduit and the other two of which are located at the other axial side of said coil means at either side of said bendable conduit.

13. A transducer as defined in claim 12, wherein said bendable conduit of said unitary laminated structure is elongated and extends in a general direction, and wherein said unitary laminated structure includes two elongated portions substantially parallel to said general direction and located to either side of said bendable conduit and each joining together the respective two projections located as the respective side of said bendable conduit.

14. A transducer as defined in claim 13, wherein said two elongated portions define with said bendable conduit two first slots generally parallel to said elongated portions, and wherein said unitary laminated structure has two second slots extending normal to said first slots and forming a continuation of said first slots and extending towards each other and two third slots extending parallel to said first slots and located between said first slots, said bendable conduit being connected to the remainder of said unitary laminated structure solely by material located intermediate said two third slots, and wherein said internal flow path extends in direction generally parallel to said third slots through the material located intermediate said two third slots.

15. A transducer as defined in claim 12, wherein said bendable conduit at said one end thereof is provided with a plurality of claw-like projections extending in direction to either side of said bendable conduit, and wherein the two of said four generally rectangular projections adjoining said one end of said bendable conduit are each provided with recesses facing and substantially complementary to said claw-like projections of said bendable conduit.

16. A transducer as defined in claim 12, wherein said electromagnetic second means further comprises two ferromagnetic yoke members each located to one respective side of said bendable conduit and each magnetically connecting the two generally rectangular projections located at the respective side of said bendable conduit, and further including permanent magnet means having a north pole connected to one of said yoke members and a south pole connected to the other of said yoke members.

17. A transducer as defined in claim 1, wherein said electromagnetic second means comprises means operative for causing said bendable conduit to bend in dependence upon energization of said second means substantially exclusively in direction parallel to the planes occupied by the facing major surfaces of said flat members.

18. A transducer as defined in claim 1, wherein at least a portion of at least one of said plurality of flat members is comprised of ferromagnetic material.

19. A transducer as defined in claim 1, wherein said flat members are glued together in pressure-tight manner.

20. A transducer as defined in claim 1, wherein said flat members are soldered together in pressure-tight manner.

Description:
BACKGROUND OF THE INVENTION

The present invention relates to a converter for converting electrical signals into fluid signals. Such a converter comprises a fluidic amplifier having a tube-like fluid passage or conduit. The amplifier is fixed at one end and made from an elastic material, its free end being movable under the influence of an electromagnetic force. The fluid passage is arranged to permit the flow of a fluid medium under a predetermined supply pressure. Its free end is located opposite to a pair of laterally spaced receiving nozzles.

The French Pat. No. 1,575,978 discloses a fluidic converter in which a jet pipe is fixed at one end to a cross-member of a metal block. A rectangular or square metal plate is arranged on the free end of the jet pipe. The metal plate cooperates together with two similar electromagnets which lie opposite each other. The metal plate is positioned in the air gaps of both the C-formed, bent iron core electromagnets. Both electromagnets are screwed to the metal block, which are again screwed to a base plate. The free end of the jet pipe lies opposite a pair of cylindrical holes or nozzles provided in one of the base plates. The nozzles are symmetrically positioned about the neutral position of the jet pipe but are oriented at an acute angle to each other. The two nozzles form part of the output orifices at which differential pressures may be measured.

However, the known electrofluidic converter has a disadvantage in that it is constructed from very many individual parts. Also, these individual parts must be finished with great accuracy, their construction requiring substantial time and precision work. For these reasons, the known converter is very expensive in its construction.

Additionally, the converter of the known variety is limited in the extent to which it may be reduced in size, because its elements can not be reduced in size when the cost of construction and assembly of the parts should remain economically justifiable.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a converter for converting electrical signals into fluid signals which does not have the disadvantages known in the prior art for similar devices.

It is another object of the present invention to provide a converter for converting electrical signals into fluid signals which is simple in construction and economical to manufacture.

It is still another object of the present invention to provide a converter for converting electrical signals into fluid signals which provides a high measure of accuracy and reliability.

It is a further object of the present invention to provide a converter for converting electrical signals into fluid signals which can be miniaturized and made more compactly than the known versions.

It is still a further object of the present invention to provide a converter for converting electrical signals into fluid signals whose critical parts may be accurately manufactured by the process of photochemical etching.

With the above objects in view, the present invention for a converter for converting electrical signals into fluid signals generally comprises electromagnet means having an air gap and producing a magnetic field across said air gap and means for charging the amplitude and direction of said magnetic field in response to electrical signals received by said electromagnet. Fluid pressure amplifier means are provided which include elongated elastic armature means located in said air gap and having one end fixed to said electromagnet means and an opposite free end, said armature means being formed with a fluid passage therethrough having an inlet end in the region of said one end of said armature means and an outlet end at such free end, said outlet end being normally located in a neutral position and being deflected to either side of said neutral position upon change of direction of said magnetic field. A pair of receiving nozzles are located opposite said outlet end for receiving in the neutral position of the latter equal amounts of fluid while in the deflected position of said outlet ends one of said receiving nozzles will receive a greater amount of fluid than the other so as to produce in said receiving nozzles a fluid pressure differential. The fluid amplifier means, including said armature means and said fluid passage therethrough as well as said receiving nozzles and at least portions of said electromagnet adjacent said air gap being formed by superimposed plate-shaped elements forming a unit.

More specifically, the objects of the present invention are achieved by providing an electromagnet and a fluidic amplifier which forms a single integrated construction. The amplifier is constructed from a number of stacked, plate-formed structural elements.

The construction of the present invention has the advantage that the main parts of the electro-fluidic converter, i.e., the electromagnet and the fluidic amplifier, are joined without special connecting elements and form a single common supporting structure and an integrated construction. The construction of the electro-fluidic converter from plate-formed structural elements makes it additionally possible to utilize photochemical etching methods. These methods have the particular advantage that complicated forms can be built very accurately and with small cost.

The armature in accordance with the present invention is also provided with core extensions, on each side thereof, which are each connected by a soft iron pole piece to a magnetic pole of a permanent magnet, a coil being wound around the armature for receiving the electrical signals and modifying the magnetic field passing through the armature and normally created by the permanent magnet.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, 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

FIG. 1 is a perspective view, partially in cross section, of an electro-fluidic converter in accordance with the present invention; and

FIG. 2 is an exploded perspective view of a portion of the converter shown in FIG. 1, showing the three plate-shaped structural elements which are stacked with one another on the final assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and particularly FIG. 1 thereof, an electro-fluidic converter is shown to comprise three stacked plate-shaped structural elements, an intermediate plate 1 and two cover plates 2, 3. These structural elements have the same contour. The structural elements generally have a middle portion and two end portions. Near the end portions of the elements, rectangular projections 4, 5, 6 and 7 are provided, the projections 4 and 5 being respectively the top left and right two projections and the projections 6 and 7 being respectively the lower left and right projections as seen in FIG. 1. Along the middle portions, rectangular bars 8 extend in a direction substantially parallel to the axis of symmetry of the converter. The width of the very narrow bars 8 is selected to just provide the required mechanical strength to withstand the stresses they are subjected to. Between the rectangular projections, 4,5 and 6,7 the coil 9 of the electromagnetic converter is wound around the bars 8.

Referring to both FIGS. 1 and 2, slots 11 are provided adjacent to the bars 8 which run substantially parallel thereto. The first slots 11 extend from the upper edges of the lower rectangular extensions 6, 7 up to the upper edges of the upper rectangular extensions or projections 4, 5.

FIG. 2 shows that the plate-shaped elements 2 and 3 serve as cover plates and are constructed identically with each other. However, the intermediate element 1 varies slightly in its construction from the other elements, as to be described. In elements 2 and 3, an armature 10, positioned within the lateral bars 8, is fixed at the lower end and free at the upper end. The material from which the armature 10 is made, as well as its design, is such as to make it easily movable at its free end between the two bars 8 in response to changes in the magnetic field applied thereto, as will be hereafter described. According to the presently preferred embodiment, the material out of which the armature 10 is made from is a soft magnetic material such as soft iron. The armature 10, at the lower end thereof is effectively held by a section which has a relatively small cross sectional area. This is accomplished by providing a pair of cross slots 13 which extend from the slots 11 inwardly as shown in FIG. 1. The second slots 13 can be seen to extend in a direction substantially perpendicular to the axis of symmetry. A further set of slots 14 is provided, which slots extend well into the armature 10, as shown, in a direction again substantially parallel to the axis of symmetry. By such a construction it becomes clear that the armature 10 is held merely at the base portion, in the lower part of the plate elements between the third slots 14, is of small cross section and therefore easily flexible.

At the free end of the armature 10, namely near the top ends of the plate elements, the armature 10 is provided with rib-like projections 15, which correspond with similar projections 16 on the inner edges of the rectangular extensions 4 and 5, The rib-like projections on the armature and on the extensions mesh with one another and cooperate to maintain the reluctance of the air gap between the rectangular extensions 4 and 5 and the armature 10 at a substantially constant value independently of the lateral deflection of the armature 10 towards one of the extensions or the other.

Again referring to FIG. 1, it is seen that each of the rectangular extensions, namely the left extensions 4, 6 and the right extensions 5, 7, are symmetrically positioned in relation to the axis of symmetry of the converter in the assembled state. The outer edges of the rectangular extensions are mated to make contact with two pole pieces 17. The pieces 17 are selected to provide a good magnetic conducting path to the magnetic flux as to be described. The top rectangular extensions 4, 5 are in contact with the upper portions of the soft iron pole pieces 17. The lower rectangular projections 6, 7 from a pair of fixed air gaps 18, 19 with pole pieces 17.

A permanent magnet 17' having generally a C or U-shaped cross-sectional area as shown in FIG. 1 cooperates with the pole pieces 17, each of said pieces being in contact with one of the poles of the magnet 17'. The coil 9 is wound around the armature 10 and extends substantially into the pole pieces 17 as shown in FIG. 1.

The upper edges of the rectangular extensions 4, 5 and the lower edges of the lower rectangular extension 6, 7 define a distance which is equal to the height dimensions of both the pole pieces 17 and the permanent magnet 17'. It becomes clear, therefore, that the pole pieces as well as the plate shaped elements complete the magnetic circuit for the permanent magnet 17'.

Referring again to FIG. 2, the details of the construction of the fluid amplifier are shown. The three plate shaped elements which form the structural building blocks of the electro-fluidic converter are shown to be of substantially similar contour. The cover plate elements 2, 3 are each provided with holes 20 in the lower portion of the latter. These holes represent inputs ports for the fluid to be regulated, as to be described. The intermediate element 1 is provided with a corresponding cut out 20' which, in the assembled state, is at least in partial alignment with the holes 20.

The intermediate element 1 is also provided with a conduit or fluid passage 21 which, in the assembled state, extends along the axis of symmetry of the converter. The fluid passage 21 is substantially a slot which extends through the entire thickness of the intermediate element 1. The cover elements 2, 3 do not possess slots along the axis of symmetry of the latter, and when the three elements are mated as shown in FIG. 1, the cover elements close opposite sides of the fluid passage 21 to thereby provide a closed conduit.

At the upper end of the armature 10' of the intermediate element 1, the fluid passage 21 is provided with a reduced cross sectional area, to thereby form a nozzle or orifice 22. The nozzle 22, which normally lies along the axis of symmetry of the intermediate element 1, is interposed opposite two receiving nozzles 23, 24. The nozzles 23, 24 are symmetrically placed about the axis of symmetry of the intermediate element 1 and are designed as diffusers having an inlet of small cross sectional area, the nozzles gradually increasing in cross sectional area in order to diffuse the liquids which are directed into the latter.

The cover plates 2, 3 are each provided with holes 25 and 26 which act as output ports, as to be described. The enlarged portions 25', 26' of the receiving nozzles 23, 24 are substantially of the same dimensions as those of the holes 25 and 26, all these being at least partially in alignment in the assembled state of the converter.

The plate elements 1, 2 and 3 are also provided with holes 27 and 28 which are provided in the presently preferred embodiment for purposes of connecting either all the plate elements together, as by means of a bolt and screw, or for connecting the converter or mounting the same to another structural element.

The butterfly shaped openings 12 are provided in all of the plate shaped elements 1, 2 and 3 and can either be placed in communication with the free atmosphere or be connected by means of a tube to a tank or reservoir.

The operation of the device will now be described.

As already noted above, the converter has one input port 20 and two output ports 25 and 26. It will first be assumed that no electrical signals are applied to the coil 9. Under normal operating conditions, the fluid is fed into the input 20 at a predetermined supply pressure. The fluid is accordingly caused to flow up the fluid passage 21 through the nozzle 22. The fluid exits from the nozzle 22 and is generally dispersed in directions along the axis of symmetry of the converter. Some of this fluid will be intercepted by the receiving nozzles 23 and 24, the latter diffusing the same and causing the fluid to be transmitted into the corresponding holes 25 and 26 which constitute the output ports. Since the armature 10 is normally in its neutral position, both the receiving nozzles 23 and 24 receive an equal amount of liquid, and the resulting pressure at the output port 25 and 26 are the same or, stated another way, the pressure differential between the two output ports is zero.

With such an arrangement the controlling element for changing the differential pressures is the armature 10 which, by means of mechanical positioning of the channel or fluid passage 21 and the nozzle 22 in relation to the receiving nozzles 23 and 24, causes more or less of fluid to be transmitted into the receiving nozzles 23 and 24, and a fluid differential pressure output signal results.

With no electrical signal applied to the coil 9, the permanent magnet 17' causes an exciting flux 29, 29' to flow from its north to its south pole as shown. The permanent magnet products this magnetic flux, most of which is caused to pass through the low reluctance magnetic circuit consisting of the pieces 17 and the plate elements 1, 2 and 3. In the upper portion of the converter, the magnetic flux passes through the left pole piece 17, the rectangular projection 4, the air gap between the rib like projections 16 and 15, the armature 10, the air gap between the rib like projections 16 and 15, the rectangular extension 5 and the pole piece 17. In the lower part of the magnetic circuit the flux passes through the left pole piece 17, the fixed air gap 18, the rectangular extensions 6 and 7, the fixed air gap 19 and the right pole piece 17. In the neutral position of the armature 10, the air gaps 18 and 19 exhibit a magnetic reluctance which is substantially equal to that which exists between the armature 10 and the corresponding rectangular extensions 4, 5. In this manner, the overall reluctance in the upper path is substantially equal to that of the lower path.

The provision of the permanent magnet 17' is for the purpose of providing a steady state or biasing flux through the upper and lower magnetic paths as described above. Now when an electrical signal is applied to the coil 9, a current is caused to flow through the coil 9, and the latter generates a magnetic control flux 30, 30' in accordance with well-known principles.

It will first be assumed that the direction of the current flowing through the coil 9 is such that the magnetic control flux 30, 30' flows in a clockwise direction on the right-hand side of the converter and in a counterclockwise direction on the left-hand side of the converter. Under these conditions, as can be seen from the directions of the flux arrows, the steady state and the control fluxes will tend to cancel one another on the top left-hand and in the lower right-hand portions of the converter while the fluxes will tend to reinforce one another in the top right and the lower left portions. Under these conditions, a force will be applied to the armature 10 towards the right which will cause the free or top end of the armature 10 to flex in that direction. When the control current is changed in its direction, so also changes the direction of the control fluxes 30, 30' and therewith the direction of the force and the deflection of the armature 10.

The rib-like projections 15 on the armature 10 and the cooperating projections 16 on the rectangular extensions 4 and 5 intermesh with one another, as described above, and have the characteristic that the magnetic reluctance of the gap therebetween is not substantially modified by the deflection of the armature 10 and is, therefore, only dependent on the strength and direction of the control current.

As described above, the fluidic amplifier of the type discussed, allows a gaseous or liquid fluid to be directed through the fluid passage 21 under a substantially constant supply pressure. After flowing through the fluid passage 21, the medium is passed through the nozzle 22 wherein the supply pressure under which the fluid exists in the fluid passage 21 is transformed into kinetic energy after passage through the latter.

When the armature 10 is in its rest or neutral position, the stream from the nozzle 22 is directed substantially equally to the left and right receiving nozzles 23 and 24. In the receiving nozzles 23 and 24, which are designed as diffusers, the kinetic energy of the streams of liquids is converted into pressure. In the neutral position of the armature 10, the resulting pressure at both of the output ports 25 and 26 is substantially equal. Thus, the differential pressure output is substantially null. When the armature 10 is now deflected, as described above, the nozzle 22 is now substantially aligned with one of the receiving nozzles more than with the other, so that there is a higher pressure in the nozzle receiving more of the fluid. The actual extent to which the pressure in one of the receiving nozzles increases is a function of the extent to which the stream reaches the respective nozzle or how much of the kinetic energy containing stream passes into the nozzle. Since the amount of liquid intercepted by one of the receiving nozzles will be a function of the position of the nozzle 22 with relation thereto, this will also be directly proportional to the deflection of the armature 10 and therewith also with the input signal, i.e., the control current.

The fluid which is not transmitted to one of the output ports 25, 26, enters the opening 12, and to a lesser extent the slots 11. In FIG. 1, the openings 12 are shown open but normally a cover plate closes these openings and the liquid contained therein may either be discharged into the atmosphere or, by means of a suitable conduit, to a reservoir or tank.

It is also possible to design the electro-fluidic converter so that the inner side of the rectangular projections 4, 5 as well as the external edges of the armature 10, 10' those smooth surfaces such as those of the fixed air gaps 18 and 19. This, of course, is a simple construction which, however, is nevertheless usable or serviceable for providing differential pressure output signals. The simple construction is particularly useful when only digital output signals are required.

In order to obtain optimum performance of the electromagnetic converter, it is preferred that the magnetic circuit be made from materials having good magnetic characteristics, such as soft magnetic material, e.g. soft iron is particularly advantageous.

Naturally, the electrofluidic converter can, when for example large currents are required or when large differential pressures are anticipated, utilize a larger number of plates and/or fluid passages which are, however, similar to those described in accordance with the present invention.

Although useful in digital circuits, the converter in accordance with the present invention is also useful in analog circuits since the differential pressures obtainable are continuously variable as a function of the current flowing through the coil 9, as explained above.

It will be understood that each of the elements described as embodied in electro-fluid devices differing from the types described above.

While the invention has been illustrated and described as embodied in a converter for converting electrical signals into fluid signals, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analyses, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.