US3648155A

US3648155A - Electromechanical transducer assembly

Info

Publication number: US3648155A
Application number: US787034A
Authority: US
Inventors: Gerhard Soehner; Gerd Hoehne
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1968-01-23
Filing date: 1968-12-26
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07
Also published as: FR1597721A; DE1673938A1; GB1258430A; NL6900022A

Abstract

An electromechanical transducer assembly wherein the magnitude of electric output signals produced by a magnetically controllable semiconductor is a function of the position of a magnetically conductive wedge or sickle with reference to an airgap in the yoke of a permanent magnet system. The semiconductor is installed in the yoke and the wedge or sickle is reciprocated or pivoted by an adjustable element of an internal combustion engine.

Description

United States Patent Soehner et a1.

[ Mar. 7, 1972 [54] ELECTROMECHANICAL TRANSDUCER ASSEMBLY [72] lnventors: Gerhard Soehner, Geradstetten; Gerd Hoehne, Ludwigsburg, both of Germany [73] Assignee: Robert Bosch Gmbl-i, Stuttgart, Germany [22] Filed: Dec. 26, 1968 [21] Appl. No.: 787,034

[30] Foreign Application Priority Data Dec. 23, 1968 Germany ..P 16 73 938.1

[52] US. Cl. ..323/94 11, 123/32 EA, 307/309, 338/32 R [51] Int. Cl ..l10lc 7/16 [58] Field otSearch ..338/32; 323/94 11; 324/45, 46; 307/309 [56] References Cited UNITED STATES PATENTS 2,712,601 7/1955 Reinwald ..323/94 H 2,866,857 12/ 1958 Andrews ..307/309 X 3,359,522 12/1967 Albrecht et a1. ..338/32 Primary Examiner-Samuel Feinberg Assistant Examiner-R. Kinberg Attorney-Michael S. Striker [57] ABSTRACT An electromechanical transducer assembly wherein the magnitude of electric output signals produced by a magnetically controllable semiconductor is a function of the position of a magnetically conductive wedge or sickle with reference to an airgap in the yoke of a permanent magnet system. The semiconductor is installed in the yoke and the-wedge or sickle is reciprocated or pivoted by an adjustable element of an intemal combustion engine.

11 Claims, 3 Drawing Figures Patented March 7, 1972 2 Sheets-Sheet 1 #1217 ArmP/wy Patented March 1, 1912 3,648,155

2 Sheets-Sheet 2 ELECTROMECHANICAL TRANSDUCER ASSEMBLY BACKGROUND OF THE INVENTION The. present invention relates to-transducer assemblies in general, and more particularly to improvements in electromechanical transducers.

German Pat. No; 1,208,897 discloses an electromechanical transducer assembly wherein a magnetically controllable semiconductor is installed in the central portion of a cupshaped magnet. Electric output signals produced by the lsemiconductorvaryas a function. of changes in the position of .aneanmature which is movablewith reference'to the magnet. "Thetarmature. defines with the central portion. an airgap of variable width, and such width changes when thelarmature is i moved by an-adjusting system to thereby bring about a change 1 in the magnitude ofoutputlsignals.

Adrawback of the just-described'transducer assembly is -.that. the zadjusting system for the. armature must exert substantial forces which are designed to effect flexing of the armature. The latter is elastic; however, its elasticity cannot be selected at will. because a highly elastic armature is likely to adhere to the magnet. It is also difficult' toproperly. calibrate thetrans- .ducerassembly in such a way that predetermined deformation of the armature bringsabout the generation of desired output signals, i.e., that vthe magnitude of output signals properly reflectsthe changes in parameters which. influence the deformation of thearmature.

SUMMARY OF THE INVENTION An object of our. invention is to provide a simple, compact and versatile electromechanical transducenassembly which can be'utilized to initiate or effect one or more adjustments in dependency on changesvin the magnitude or other characteristics of a single parameter or two or more parameters.

Another objectof the invention is to provide a transducer assembly which can produce electric output signals and :wherein the adjust-ment of the part or parts which immediately determine the magnitude of such signals necessitates the exertion'of small forces. 7

.A further object of the invention is to providea' transducer assembly which can be-used-with advantage-in automotive vehicles, particularly in road vehicles, to regulatethe opera- 1 tion of one or more systems in dependency. on one or more 1 variable factors, such .as the position of the throttle, the pressurein the intake mainfold; the rotational speed of the engine, the .level=of fuel in the tank, the position of the front or rear axle, and/or others.

One feature of our invention resides in the provision of an electromechanical transducer assembly which comprises .magnetmeansdefiningatleast oneairgapacross which the magnetic force lines extend, at leastone semiconductor (e.g., a Hall effect generator or amagnetically controllable resistor) extending acrossBthe magnetic force lines of the magnet means and arranged to generate or to initiate generation of electric outputsignalswhose magnitude is a function of the condition ofwthe magnetic field adjustable regulating means of magnetically eonductive materiahand adjusting means for adjusting :the regulating means with reference to the :gap so that the regulating means changes the condition of the magnetic field .andhence the magnitude of output signalsasa function of its :position relative to the gapJThe changes in condition of the :magnetic fieldmay=depend exclusivelyzon changesin the position-of the regulating-means and/or on specific configuration of the regulatingmeans. Such regulating means may resemble a wedge, a sickle or anotherbody of varying cross-sectional area and. may be caused to move between flat parallel or otherwise oriented -or configurated surfaces flanking the airgap. Signals produced by the semiconductor can :be.used to v controlith e position of headlights in a vehicle, to delayxthe spark in'the ignition system ofaniintemal combustion engine, a to regulate the: amounts of fuel'injected by the fuel injection I system of an engine,-to regulate the position of a fuel gage, to shift an automatic transmission, to adjusta clutch and/or for other purposes.

The novel features which are considered as characteristic of with additional features andadvantages thereof, will be best :understood uponperusal of the following detailed description .of certainispecific embodiments-with reference to the accomapanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is aperspective viewof a first electromechanical transducer assembly which is designed to delay the spark in the ignition system of an internallcombustion engine as a func- '-tion of pressure changes in the intake manifold;

FIG. 2 is a similar perspective view of a-second transducer assembly which is utilized to regulate-the amounts of injected :fuel as a function of changes in the position ofthe throttle in the intake manifold of an internal combustion engine; and

FIG. 3 is a perspectiveview of a transducer assembly which i is used to change the direction of light beams produced by the headlights of an automotive vehicle in dependency on the position of the rear axle with reference to the chassis.

. DESCRIPTION OF .THE' PREFERRED EMBODIMENTS FIG. 1 illustrates an electromechanical transducer-assembly which comprises apermanent magnet ll-whose magnetic force lines passthrough a'U-shaped yoke l2-which abuts against the poles, of the magnet and one leg of which accommodates a magnetically controllable semiconductor 13. The yoke .12 is further provided with an airgap l4. Thesemicon- 'ductor 13

hasrterminals

13, 13" which transmit electrical output signals to acontrolled assembly. The magnitude of such output signals depends on the position of a substantially wedge-shaped regulating or control member 15 which consists of magnetically conductive material and can be moved with reference to the gap 14. The regulating member 15 is connected to a coupling rod.l6 whichforms part of an adjusting unit'and is'reciprocable by a motion-transmitting member 17 here shownas a flexible diaphragm which is installed in a housing 18. The latter forms part of an internal combustion engine which includes an intake manifold 21 and a pipe 20 which connects'the interior of the manifold 21 with one chamber 184 of the housing 18. The chamber'l8a further accommodates a helical expansion spring 22 which tends to flex the diaphragml7 into the other chamber 18b of the housing .18. The chamberl8b communicates with the atmosphere. Each position of the diaphragm l7 and coupling rod 16 corresponds to a different output signal at the terminals 13', 13".

Such changes .in position. of the diaphragm 17 influence the condition of the magnetic field in which the'semiconductor l3 isinstalled.

The magnitude of output signals at the terminals 13', 13" further depends on the configuration of the regulating member l5.'This membenlS is reciprocable'along a straight path extending at right angles tothe direction of magnetic force lines .in the adjoining part of the yoke 12, i.e., at right angles to the-path of magnetic force lines across the gap 14. The

regulating member 15 has two end faces 23, 24 which are parallel to the direction of magnetic force linesin the gap 14 and'normal to theaxis of the coupling rod 16. The cross-sec- -tional area of a portion of the member l5 diminishes in a -"direction from the end face 24 toward the end face 23. The

26whichflankthe gap 14 in the yoke 12 are parallel to each other and to the axis of the coupling rod 16. The adjoining side faces. 27,'28-of the regulating member. 15 are parallel to the surfaces 25,26 and normal to the end faces23, 34. At least one of :the remaining faces 29, 300i the regulating member is inclined with reference to the axis of the coupling member 16. In'the illustrated embodiment, the bottom face 30 is parallel to such axis but a portion of the top face. 29 is inclined to insure that the cross-sectional area of the regulating member diminishes in a direction from the end face 24 toward the end face 23.

The output signals produced by the semiconductor 13 can be utilized to delay the spark in the ignition system of the internal combustion engine. The ignition system comprises a timer G which is actuated by the internal combustion engine and serves to normally initiate ignition in a predetermined angular position of the crankshaft. The timer G influences an electrical control unit S which is operatively connected with a high-voltage generator H to effect the generation of a highvoltage impulse which causes the generation of a spark between the electrodes of a spark plug Z. The output signals at the terminals 13', 13" of the semiconductor 13 are trans mitted to the control unit S and influence the latter in such a way that the timing of high-voltage impulses (and hence the generation of sparks between the electrodes of the spark plug Z) is either advanced or delayed proportionally with the magnitude of output signals. I

It is also possible to effect axial movements of the coupling rod 16 in dependency on rotational speed of the internal combustion engine. For example, the crankshaft of the engine can actuate a customary centrifugal governor which controls the position of the regulating member 15, either directly or by way of the coupling rod 16.

The parts 16-22 together form an adjusting unit which reciprocates the regulating member 15 back and forth along a straight path. The cross-sectional area of the member 15 varies in one of the directions of such reciprocating movement.

FIG. 2 illustrates a second transducer assembly wherein the adjusting unit for the regulating member 115 comprises a throttle 117 which is adjustable in the intake manifold 121 of an internal combustion engine. The shaft 31 of the throttle can be turned by a gas pedal 31. This shaft 31' further carries one element of a transmission which serves to reciprocate the regulating member 115 with reference to the magnet means 111, 112 as a function of the angular position of the throttle 117. The transmission includes a cylinder cam 33 which is coaxially affixed to the shaft 31' and is provided with a suitably configurated peripheral cam groove 33 for an output member or follower 34 installed at one end of a coupling rod 35 which is connected to and moves the regulating member 115. The coupling rod 35 is reciprocable in a stationary bearing element 36. The regulating member 115 is movable at right angles to the magnetic force lines in the gap 114 of the yoke 112. The manner in which the semiconductor 13 is installed in one leg of the yoke 112 is the same as described in connection with FIG. 1. In its simplest form, the regulating member 115 could constitute a parallelepiped (six-sided prism) with three pairs of parallel rectangular faces. If such a simple prismatic body were moved across the gap 114 between two parallel surfaces of the yoke 112, the magnitude of output signals at the

terminals

13, 13" of the semiconductor 13 would be a substantially linear function of the extent of penetration of the regulating member into the gap. The configuration of the cam groove 34 is then the main factor which detennines the magnitude of output signals in response to angular displacement of the throttle 117.

It is clear that the transmission including the cam 32 and output member 34 is but one of several transmissions which can be utilized in the adjusting means for the regulating member 115. For example, the cylinder cam 32 can be replaced by a disk-shaped cam and the output member 34 can be replaced by a roller or the like.

In the transducer assembly of FIG. 2, the magnitude of output signals at the terminals 13', 13" is not merely a function of the configuration of the cam groove 33 but also a function of a special configuration of the surfaces 125, 126 which flank the gap 114 and of

faces

123, 124, 127, 128, 129,130 on the regulating member .1 15. The cross-sectional area of the regulating member 115 varies in a direction from the end face 123 toward the end face 124. However, the top and bottom faces 129, 130 are parallel to each other and to the directions of reciprocatory movement of the coupling rod 35. Therefore, one of the side faces 127, 128 (namely, the side face 127) is of concave shape and its configuration conforms to that of the convex surface 125 on the yoke 112. It is clear that the crosssectional area of the regulating member can be varied by appropriate changes in configuration of the side face 128 and/or by changing the inclination of two or more of the faces 127-130. For example, the surface l26 may be a mirror-symmetrical image of the surface and the side face 128 may be a mirror-symmetrical image of the side face 127.

The output signals at the terminals 13', 13" of the semiconductor 13 shown in FIG. 2 are utilized to regulate the operation of a fuelinjection system in the internal combustion engine which includes the intake manifold 121 and throttle 117. The injection system comprises a timer G which is operated by the engine to normally initiate injection of fuel in a predetermined angular position of the crankshaft. The timer G is connected with an electrical control unit S which receives signals from the terminals 13', 13" and controls the amounts of fuel which are injected by one or more valves V. In the illustrated embodiment, the position of the throttle 117 determines the amounts of fuel which are injected by the valve or valves V by determining the magnitude of output signals at the terminals 13', 13". The amounts of injected fuel further depend on the ratio of the transmission 32-34 and on specific configuration of the regulating member 115. In this way, the amounts of injected fuel can be readily determined as a function of several factors to insure optimum operation of the enginein different positions of the throttle 117. Such optimum operation can be achieved with a very simple and compact assembly. It is further clear that the adjusting means of FIG. 2 can be replaced by other adjusting means, for example, by the aforementioned centrifugal governor which can shift the regulating member 115, either directly or by way of the coupling rod 35, as a function of changes in rotational speed of the engine.

FIG. 3 illustrates a third transducer assembly wherein the adjusting means for the regulating member 215 comprises an axle 217 in an automotive road vehicle. This axle is biased downwardly by a spring 37 which reacts against the frame or chassis 38 of the vehicle. The coupling device of the adjusting means comprises a rod 39 which is connected with the axle 217 and has a pin 39 extending into an elongated slot 40 pro vided in one arm of a lever 40 for the regulating member 215.

' The lever 40 is pivotable about the axis of a pin 41 provided on the magnet means 21 l, 212. The other arm of the lever 40 carries the regulating member 215 and is designed to move the regulating member with reference to the gap 214 in the central portion of the yoke 212. The terminals 13', 13" of the semiconductor 13 are connected with the terminals of an electromagnet E which is in circuit with an energy source B and has an armature C coupled to a rocker arm O which is connected to a turnable support or carrier A for two light sources L, i.e., for the headlights of the vehicle. The purpose of the transducer assembly is to change the direction in which the headlights L direct beams of light D as a function of the position of the axle 217 with reference to the chassis 38. When the distance between the axle 217 and the chassis 38 decreases. the lever 40 moves the regulating member 215 away from the gap 214. The exact rate of adjustment of the headlights L in response to movements of the axle 217 relative to the chassis 38 is also a function of a specific configuration of the regulating member 215. This member has

parallel faces

229, 230 and resembles a sickle which tapers in a direction from the end face 224 toward the other end face 223. The side faces of the regulating member 215 converge toward each other in a direction from the end face 224 toward the end face 223. The extent of penetration of the regulating member 215 into the gap 214 depends on the extent of displacement of the axle 217. The magnitude of output signals at the terminals 13', 13"

of the semiconductor 13 is a function of such displacement of the axle 217 (i.e., a function of the position of the regulating member 215 with reference to the gap 214) .andalsoa function of specific configuration of the-member 215. The purpose of the transducer assembly shown in FIG. 3 is to insure that the angle betweenthedirection in which theheadlights L emit light rays D and the road surface remains unchanged irrespective of changesin the distance between .the axle 217 and the chassis 38. If desired or necessary, the transducerassembly may comprise one or more amplifiers between the semiconductor 13 and theelectromagnet-E. The characters F denote two bearings-which rotatably support thecarrier A for the headlights L.

The axle 217 is assumed to be the rear-axleof'the vehicle. A

reduction'in.the'distance between theaxle 217 and the'chassis 381causes'the armature Ctomovein thedirectionindicated by arrow e. If'the vehicle comprises a second transducer assembly which is installed between the front axle (not shown) and the carrier A forthe headlights L,'the second transducer assembly is designed to change'the angular position of the carrier A by movingthe armature Cor the armature of a second electromagnet in the'directionof arrow e" when the distance between the chassis and the front axle decreases. In other words, a reduction in the distance between the chassis and the front axle brings aboutanadjustment in the angular position of the carrier Awhich is exactly contrary to adjustment taking place inresponse to a reduction in thedistance betweenithe axle 217 and chassis 38.

It is clear that the carrier A of FIG. 3 can be adjusted by the transducer assembly of'FIG. l or 2, either directly or by way of a suitable transmission or amplifier system. By thesame token, the transducer. assembly of FIG. 2 or 3 can be usedto delay the spark or the transducer assembly of FIG. 1 or 3 can be used to regulate the amounts of injected fuel.

It is further possible to employ the improved transducer assembly as a means for changing the ratio of an automatic transmission in an automotive vehicle or the like. For example, the transducer assembly of FIG. 1, 2 or 3 can include an adjusting device in'the form of a centrifugal governor which adjusts the position of the regulating member 15, 115, or2l5 in dependency on .rotational speed of the engine, and the semiconductor 13: then produces output signals which are utilized .to change the ratio of the transmission. Also, the semiconductor l3.can controlthe operation of the clutch in an automotive vehicle.

Still further, the transducer assembly can be utilized to indicate. the amounts offuel in the tank of a=vehicle. The adjusting means then comprises a float which is installedin thefuel tank sothat its position changes as a function of changes in positionof the fuel level and causes appropriate changes in position of the regulating member 15, .115 or 215. The semiconductor 13 then produces output signals which are utilized to change the position of a needle or another suitableindicator which indicates the amounts of fuel in'the tank. The exact shape of the fuel tank is of no consequence because the rate'at which the regulating member is displacedin response to decreasing level of fuel in the tankcan be multiplied by resorting to a suitable transmission or other means for insuring readily detectable changes in the position of the indicator in response to relatively small changes in the level of fuel.

It is further clear that the transducer assembly of our invention may comprise'magnet means with two .or moreairgaps and a separate regulating member for each gap. Each such regulating member is then preferably connected .with a separate adjusting device so that the magnitude of output signals produced by the semiconductor is a function of two or more parameters. Furthermore,the transducer assembly may embody two or moremagnetically controllable semiconductors each of which produces a. discrete output signal and wherein each such output signal can be used to regulate a different system. The magnet means may employ electromagnets as a substitute forpermanent magnets.

The semiconductor 13. may constitute a magnetically controllable resistor or a Hall effect generator.

' magnetic force Without further analysis, the foregoing will so fully reveal rthe-gist of the present invention that otherscan, by applying current :knowledge, readily adapt it for various applications without omitting features which .fairly constitute essential characteristics of the generic and specifictaspects of our con- .tributionsto the art.

What is claimed as new. and desired to-be protected by Let- :ters Patent is set forthin the appended claims.

1. An electromechanical transducer.assembly comprising -magnet meansdefiningat least one airgap across which the magnetic force :lines extends; magnetically controllable semiconductor :means extending across the magnetic force -lines of saidrmagnet means'and arranged'toproduce electric output signalswhosemagnitude is a'functionof thecondition of the=magnetic'field; at least'one component whose change of position is to-be monitoredycontrolmeans of magnetically .conductive material for changing the conditionofsaid mag- "netic-fieldand:hencethemagnitudeof saidoutput signals as a .magnet means comprises a magnet and a.yoke-,ofmagnetizable material having ends adjacent'to the poles of said magnet, said semiconductor/means being installed in said yoke and said gap being provided in said yoke.

.3. Atransducer assembly asdefinedin claim 1 wherein said .control means has'two end-faces and-the cross-sectional area thereof diminishes at least inpartfrom one of said end faces toward'the'other end face.

4. A transducer assembly asdefined in claim 1, wherein said adjusting means comprises a.transmission having an output member connected with said control means.

5. A transducerassembly as defined in claim 1 wherein said control .means is 'pivotable with reference to said magnet .means about a predetermined-axis.

6. A transducer. assembly as defined in claim 1, wherein at least one portion ofsaid controlmeans is movably arranged in said airgap. and-wherein saidsemiconductor means extends across .said magnetic lines of force of said magnet means .spaced from said airgap and is stationarily arranged with respect to said magnet means.

7. .An .electromechanical transducer assembly comprising magnet means .defining'at least-one airgap across which the lines extend; magnetically controllable semiconductor means extending across the-magnetic force lines of said magnet means and arranged to produce electric output signals whose magnitudeis afunction. of the condition 'of the magnetic field; at least one component whose change of position is to .be monitored; control means of magnetically conductive material for changing the condition of said magnetic fieldand hence the magnitude of said output signals as a function of changes'in the position of said control means with referencetosaid gap; andadjusting means connecting said component to;said control means to-reciprocate the latter relative to said .gap along a straight path: at right angles to the direction of magnetic force linesacross said-gap to achieve a desired functionaldependence between the change of position of said component and said magnitude of said output signal of said magnetically controllable semiconductor means.

- 8. An electromechanical transducer assembly comprising magnetmeansdefining at least one airgap across which the magnetic force lines extendand comprising a pair of parallel 'surfaces defining said gap; magnetically controllable semiconaductor means extending across the magnetic force lines of said magnet means and arranged to produce electric output signals whose magnitude is a function of the condition of the magnetic field; at least one component whose change of position is to be monitored; control means of magnetically conductive material for changing the condition of said magnetic field and hence the magnitude of said output signals as a function of changes in the position of said control means with reference to said gap, said control means comprising a pair of first faces parallel to said surfaces, a pair of second faces extending transversely of said first faces, and a pair of third faces extending between said second faces, at least one of said third faces being at least partially inclined with reference to the other third face so that the cross-sectional area of said control means varies in a direction from one towards the other second face thereof; and adjusting means connecting said component to said control means to move the latter relative to said airgap in such a manner to achieve a desired functional dependence between the change of position of said component and the magnitude of said output signal of said magnetically controllable semiconductor means.

9. A transducer assembly as defined in claim 8, wherein said adjusting means is arranged to move said control means back and forth in directions substantially at right angles to said second faces.

10. An electromechanical transducer assembly comprising magnet means defining at least one airgap across which the magnetic force lines extend and comprising a pair of surfaces flanking said gap; magnetically controllable semiconductor means extending across the magnetic force lines of said magnet means and arranged to produce electric output signals whose magnitude is a function of the condition of the condition of the magnetic field; at least one component whose change of position is to be monitored; control means of magnetically conductive material and comprising a pair of faces each adjacent to one of said surfaces for changing the condition of said magnetic field and hence the magnitude of said output signals as a function of changes in the position of said control means with reference to said gap; and adjusting means connecting said component to said control means to move the latter relative to said airgap in such a manner to achieve a desired functional dependence between the change of position of said component and the magnitude of said output signal of said magnetically controllable semiconductor means, at least one of said faces of said control means being located in a plane which is inclined to the direction of movement of said control means by said adjusting means.

11. A transducer assembly as defined in claim 10, wherein the configuration of said one face is substantially parallel to that of the adjacent surface.

t i t I

Claims

1. An electromechanical transducer assembly comprising magnet means defining at least one airgap across which the magnetic force lines extends; magnetically controllable semiconductor means extending across the magnetic force lines of said magnet means and arranged to produce electric output signals whose magnitude is a function of the condition of the magnetic field; at least one component whose change of position is to be monitored; control means of magnetically conductive material for changing the condition of said magnetic field and hence the magnitude of said output signals as a function of changes in the position of said control means with reference to said gap, the cross-sectional area of at least a portion of said control means diminishing in a predetermined direction; and adjusting means connecting said component to said control means to move the latter relative to said airgap in and counter to said predetermined direction to achieve a desired functional dependence between the change of position of the component and the magnitude of said output signal of said magnetically controllable semiconductor means.

2. A transducer assembly as defined in claim 1 wherein said magnet means comprises a magnet and a yoke of magnetizable material having ends adjaceNt to the poles of said magnet, said semiconductor means being installed in said yoke and said gap being provided in said yoke.

3. A transducer assembly as defined in claim 1 wherein said control means has two end faces and the cross-sectional area thereof diminishes at least in part from one of said end faces toward the other end face.

4. A transducer assembly as defined in claim 1, wherein said adjusting means comprises a transmission having an output member connected with said control means.

5. A transducer assembly as defined in claim 1 wherein said control means is pivotable with reference to said magnet means about a predetermined axis.

6. A transducer assembly as defined in claim 1, wherein at least one portion of said control means is movably arranged in said airgap and wherein said semiconductor means extends across said magnetic lines of force of said magnet means spaced from said airgap and is stationarily arranged with respect to said magnet means.

7. An electromechanical transducer assembly comprising magnet means defining at least one airgap across which the magnetic force lines extend; magnetically controllable semiconductor means extending across the magnetic force lines of said magnet means and arranged to produce electric output signals whose magnitude is a function of the condition of the magnetic field; at least one component whose change of position is to be monitored; control means of magnetically conductive material for changing the condition of said magnetic field and hence the magnitude of said output signals as a function of changes in the position of said control means with reference to said gap; and adjusting means connecting said component to said control means to reciprocate the latter relative to said gap along a straight path at right angles to the direction of magnetic force lines across said gap to achieve a desired functional dependence between the change of position of said component and said magnitude of said output signal of said magnetically controllable semiconductor means.

8. An electromechanical transducer assembly comprising magnet means defining at least one airgap across which the magnetic force lines extend and comprising a pair of parallel surfaces defining said gap; magnetically controllable semiconductor means extending across the magnetic force lines of said magnet means and arranged to produce electric output signals whose magnitude is a function of the condition of the magnetic field; at least one component whose change of position is to be monitored; control means of magnetically conductive material for changing the condition of said magnetic field and hence the magnitude of said output signals as a function of changes in the position of said control means with reference to said gap, said control means comprising a pair of first faces parallel to said surfaces, a pair of second faces extending transversely of said first faces, and a pair of third faces extending between said second faces, at least one of said third faces being at least partially inclined with reference to the other third face so that the cross-sectional area of said control means varies in a direction from one towards the other second face thereof; and adjusting means connecting said component to said control means to move the latter relative to said airgap in such a manner to achieve a desired functional dependence between the change of position of said component and the magnitude of said output signal of said magnetically controllable semiconductor means.