DE1566791A1 - Electrical control value transmitter - Google Patents

Description

IBERLJN 33 8 MUNICH

Augu.te-Viktoria-Straa _e 65 Dr.- I Π Q. HANS RUSCHKE Pienzenauer Strasse

Pat.Anu / Πγ Ruscfike & ■ - Pat. · An wait Agular

Telephone: 0311 / || ™ ^ Dl pi.-I ΠQ. HEINZ AG U LAR Telephone: 0811 / «« ^

Poetecheckkonto: PATENTANWÄLTE Postscheckkonto: Berlin betting 74 94 Munich 662 77 Bank account:. Bank account: Bank f. Trade and Industry Dresdner Bank EZÄ "Ί 0 D D / 3 I Some

5 ι'ϊ. »» Μ Dep. Cash desk Leopoldstrasse

Teplitzer Strasse 42 ,,,; _K0 , _1K ^H

Account 32 7608 Account 69 615

T.legr.mm-Adrei. ·: Telegram address: Quadrature Btriln Quadrature Monks

S 1228 / BI

Dr.-Ing. Joseph F. Schugt, 2182 E. Seventh Street, 8t. Paul, Minnesota 55119 »U.S. A.

Electrical manipulated variable transmitter

The invention relates to electrical signal generators which respond to the adjustment of an input member and in particular to highly sensitive ones Signal transmitters in which the input member has several closely spaced control elements.

Electrical signal generators have long been known which have two inductively coupled coils separated by an air gap, and in the case of the various types of design of the parts of the controlling element that protrude into the air gap, the transmission of magnetic flux is influenced differently between the two coils. With such an arrangement, the adjustment changes of the controlling element the inductive coupling of the two coils, whereby the release of electrical signals in certain positions deo controlling member can be effected in various ways.

The disadvantage of the known devices of this type is that the

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The bundling and concentration of the magnetic lines of force detected by the controlling member in the air gap is not sufficient to achieve high positional sensitivity. This disadvantage makes it particularly difficult to achieve high resolution in the control value transmission, in which the controlling element, for example in the form of a rotatable disk, has a large number of small, closely lined up segments which are to be moved through the air gap at high speed.

An object of this invention is to provide an apparatus of the type described Kind, which is very sensitive to position and which leads to very small changes in the position of the movable control element is able to grasp.

Another object of this invention is to provide an apparatus in which the movable control member is in the form of a has rotating disc that can be adjusted at a relatively high rotational speed.

According to the invention, these tasks are solved by the special Design of the electromagnetically enclosing the coil cores Shielding, which has small openings through which the induction flux passes in the air gap to a relatively large extent small cross-section is limited, the shield does not extend only to the facing, air gap sides Coil ends, but surrounds the two bobbins and

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bridges the air gap with the effect that the magnetic lines of force crossing the air gap around the pole axis run close together.

The control value transmitter according to the invention is preferred equipped with an electrical circuit arrangement in which one of the two inductively coupled coils is used as a voice coil a high-frequency alternating current oscillator, the other serves as an associated feedback coil, so that the high-frequency i.'AC current according to the position of the control element is modulated.

Further features of this invention will be apparent from the following description the details, the claims for protection and the attached drawings.

Fig. 1 shows a schematic representation of the electrical control value transmitter with the improved inductive Position tapping and associated block diagram.

Fig. 2 shows an oblique view of the pick-off coil set with its · holder.

Fig. 3 shows the tap shown in Fig. 2 in connection with a control member designed as a rotatable disk; the potting compound surrounding the pick-up coils and a part the shield and bracket are shown in section.

4 gives an enlarged and exploded overview the coil and shielding details of the inductive position pick-up.

Fig. 5

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Pig. 5 shows a plan view of the rotatable control disk

miy average input wave. Fig. 6 shows a different one in the same view as Fig. 5 Formation of the movable control member of the tap.

As shown in FIG. 1, the inductive tap consists of one energized by a high frequency power source coil (11) and one with this inductively coupled secondary coil (12). In the air gap between these two coils (11) and (12) protrudes the edge of a disc (15) »which in any way quickly or can be rotated slowly, and the change in position detected by the tap and electrical signals at the output the arrangement delivers.

As best seen in Figure 5, there is the control member (13) made of an electrically conductive metal disc, for example made of aluminum, the edge of which is provided with a number of closely spaced teeth (14). In the In the form shown in the figure, these teeth are shown distributed uniformly over the circumference of the sole plate, for example. The teeth (14) grasp and suppress when stepping through through the air gap between coils (11) and (12) the magnetic flux transfer from coil (11) to coil (12).

As shown in Fig. 1, the coil (11) is on a high. frequency oscillator (15) rait the output terminals (16) and

(17) connected, its connections for the coupling

(18) and (19) are connected to coil (12). The effect of the

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Feedback is preferably regenerative - that is, the high-frequency oscillation is maintained as long as the coils (11) and (12) are sufficiently strongly inductively coupled to one another. If, however, as a result of one of the teeth (14) passing through If the air gap, the alternating magnetic flux between the coils (11) and (12) is suppressed, the oscillation of the oscillator ceases. The output voltage curve of the oscillator over time is shown schematically by the wave train (23) in the event that the disc (13) is rotated smoothly; when wandering through a The gap between the teeth of the control disk (13) through the air gap can be seen how the vibration amplitude grows rapidly and sharply to zero falls off again. Every time none of the teeth (14) cross the air gap blocked, the high-frequency oscillation builds up again. The amplitude-modulated output voltage of the obtained in this way The oscillator becomes a demodulator via connections (20) and (21) (22), which filters out the high-frequency oscillation and its output voltage is represented by the curve (25) is. The demodulator output voltage becomes a normal Schmitt trigger circuit (27), the rectangular output voltage curve of which is shown in curve (28). The steep flanks of the Hechteck output voltage curve correspond to the passage of the Flanks of the control disk teeth (14) through the pickup pole axis. If the timing disk (I3) turns uniformly, the Frequency of the square wave pulses (28) in a fixed ratio to the angular velocity the control disc (13)

From Fig. 2 ipt it can be seen that the two with an insulating

Potting compound surrounded coils (11) and (12) on a holder made of 00985 2/03 5 0 strong

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strong sheet metal, the bent end of which is provided with a screw opening (32J) is used to attach the entire tap. The details of the connection of the coils (11) and (12) with the holder can best be seen in Fig. 3 zn , which shows the potting compound cut open.

Referring to Figures 2 and 3, it can be seen that the holder (30) made of conductive material with its longitudinal web (33) forms part of the shielding and with the coils (11) and (12) and the remaining shielding parts described below forms a structural unit. The arrangement of the control disk (13) in relation to the coils (11) and (12) can be seen from FIGS. 1 and 3. The control disk (13) by suitable means on an input shaft (35) BEFE ⁰ + .- * f? T over which is initiated to be detected.

An important detail of this invention is the design of the shielding surrounding coils (ii) and (12). that each of the coils (11) and (12) is surrounded by a cylindrical jacket (4U) and (4I) made of shielding plate. Each of these The shielding jacket has a longitudinal foot, (42) and (43) over the extends the entire length of the jacket. At the one facing the air gap The end of the jacket plate (40) is a flat metallic shielding tube (45) provided, plural marriage has a slot (46) which extends from the upper edge center slightly below the longitudinal web (33) extends to below the lower edge of the pole core of the coil (11). The slot (46) in the shielding plate (45) is original narrow and corresponds approximately to the width of the joint (42) in the Abaohirmmantel (^ u).

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The shielding frame (4I), which includes the coil (12), closes

at
a shielding plate (49V »which, in a similar manner, has a slot

(50), which extends from the upper edge of the plate (49) to slightly below the magnetic pole core (51) of the coil (12) -stretched. The width of the slot (5O) is the same as that the joint (43) in the shielding jacket (41)

The shielding area (49) in the vertical direction is slightly longer than the surface (45) »a further narrow shielding surface (53) ^a US leitendemiuaterial joins the screening surface (45) on, such that a narrow gap between the upper edge of the shield ( 45) and lower edge of the shielding surface (53).

The upper edge of the shielding plate (49) and the upper edge of the sheet metal strip (53) are at the same height and close to the longitudinal web (33) ^a &. I> ^he conductive longitudinal bar (33) causes an additional limitation of the magnetic force flow path between the coils (11) and (12) to a narrow cross-section which is either obstructed by the teeth (14) of the control disc according to the position of the control disk or released.

With the outer end of the Abschirraraantels (40) of the coil (11) is an end plate (56) of insulating material cast on which metallic connection pieces (57) and (50) are attached to which the / ickluncEnds of the coil (11) are attached. In a similar way // There is also an insulating one at the outer end of the shielding jacket (4I) Plate (60) provided which the connections (61) and (62) for the

Üi-ule (12)

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Coil (12) carries. The finished cast coils (11) and (12) are except for the outer ends, the narrow casing joints (42) and (45)> the slots (46) and (5θ)> and the narrow joint between the shielding surfaces (53) and (45) is shielded by vöMg. The fully encapsulated tap system forms a unit similar to that shown in «Fig. 2 and 3 shown. The individual, made for themselves and both coil blocks encapsulated with their shields are attached to the with a synthetic resin adhesive such as epoxy Longitudinal web (33) of the holder glued on. The outer ends of the coils can also be shielded; however, since this is not a brings a significant improvement, the outer ends can remain magnetically unshielded, as shown in the figures.

The shielding elements (45) »(49) and (53)> must be made of conductive material and are described in the previous description referred to as shielding plates. However, it can be more beneficial in certain circumstances be the shielding surface (49) and the two shielding surfaces (45) and (53) to be produced together from copper-clad insulating material, e.g. fiberglass, whereby the non-conductive base seats (46) and (50) and the parting line between shielding surfaces (45) and (53) are formed by etching away the copper.

While in the above description the shielding jacket surfaces (40) and (41) shown with continuous longitudinal joints (42) and (43) is a shortening or even complete omission of the parting line permissible, provided that the jacket diameter is chosen to be sufficiently large and that the outer slot between the shielding

fleaten

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(53) and (45) lies within the jilantejimfang such that the air gap side entry as well as the exit of the coil (11) penetrating magnetic lines of force within the Sheath (40) can be done.

The course of the closed loop generated by the excitation coil (11) Magnetic lines of force emanate from the pole of the coil core (44) on the air gap side from the shielding slot (46) hot into the air gap in and returns through the transverse slot between the shielding covering (45) and (53), the casing joint (42) near the outer end of the Coil core back into the pole core (44). A small part of the lines of force entering the air gap from the pole core (44) passes through the slot (50) into the inner end of the coil core (51) and after flooding through the coil (12) through the casing joint (43) »äen slot (50)> the transverse slot below the shielding surface (53) and then through the casing joint (42) as well back to the outer end of the coil core (44) If there is no tooth (14) on a control disk, the flow is longitudinally developed the common central axis of the poker hindered. The horizontal transverse joint between shielding surfaces (53) and (45) brings opposite The bare pole shielding by means of vertically slotted metal end faces similar to part (49) is a significant improvement. The (irund for the special effect is evidently to be seen in the fact that the Mafe'nobische Kraftfiuasaribeil, which from the slot (50) in the Abachirmflache (49) returns into the air gap, deflected downwards before he goes through the transverse joint between Abuchirmfläohen (53) and (45) came back to the Wrro ^ errumle on the above-described bird. Dubai viird dieuer Kraftflusiiantoil before it liintritb in the

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Mantle joint (42) compressed towards the middle, which equates to an increased bundling and centering of this force line flux component, which is susceptible to the control effect. If the shielding surface (45) had the same shape as the shielding surface (49) *, the deflection of the return flow of the lines of force would occur and its favorable orientation towards the center of the reel are omitted, which results in a less precise control effect the teeth (14) would result.

Note that the bobbin (44) is shorter than the bobbin (51). The coil core (51) is intended to achieve an effective inductive coupling relatively To be long. On the other hand, the coil core (44) of the excitation coil should be relatively short, taking into account that it is kept low the losses due to high frequency.

By compressing the magnetic flux on the narrow paths provided by the slots (42), (46), (43) and (50), it is achieved that the tap is extremely sensitive to small changes in the position of the teeth (14) of the Control disc (13) responds. This makes it possible to build a device with high sensitivity without having to use extremely small manufacturing tolerances, as is required with other inductive pick-up systems. If an air gap of 2.5 to 3 ^{mm is used,} does el Lt-? Shielding according to the invention has a tap sensitivity which, with known tap arrangements, would require the use of an air gap of approximately 0.6 mm. It is mil. The new one

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Arrangement using a control disc (15) from about 10 cm in diameter and 60 teeth succeeded in triggering 60 pulses per revolution up to one Frequency of several thousand per second.

The use of the above-described shielding arrangement in Connection with a Schmitt trigger or a similar circuit for sharpening the planks of the output pulses it is easily possible to use a very compact device with sharp pulses per revolution of the control disc (.13) 60 teeth can still be obtained at a rotational speed of the input shaft of 10,000 revolutions per minute.

While an electrically conductive control disk is described above whose teeth alternately suppress and release the magnetic flux of lines of force it is also possible to use a control disk with the opposite effect; i.e. that in such a case it is magnetic active teeth reinforce the inductive coupling between the two coils of the position pick-up instead of the previous one discussed, weaken. However, it has been found that a much better control effect is obtained when a non-magnetic metal is chosen as the material for the teeth of the control disk. The flow-restricting effect an electrical conductor transverse to the high-frequency magnetic alternating field proves to be the material more effective for the teeth of the controlling member than the flow-promoting effect of a magnetic material.

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In some cases, however, the additional occupancy of the teeth made of nonferrous material of the Control disc with small core pieces made of ferromagnetic material as for a further improvement of the control effect proved useful.

While in the above description an oscillator (15) is described, the oscillation of the minimum strength of the inductive Coupling between the coils (ll) and (12) is dependent, This oscillation can also be achieved by means of an auxiliary device connected to the oscillator - e.g. in the form of a multivibrator - be favored. This multivibrator delivers filtered, sharp excitation pulses of lower frequency

sequence, e.g. 1/5 of the natural frequency of the oscillator; by Artificially excited oscillator oscillation only sways when there is no tooth (l4) on the control disk (lj5) impeded inductive feedback between the two pick-off coils. In this way you get a constant High-frequency oscillation only in those positions of the control disk (13) in which there is no tooth (14) in the air gap axis is located.

Modification of Figure 6

Fig. 6 shows a control disk (70) made of insulating material with a series of conductive metallic segments (72) is equipped. These segments can be made in any of several ways as are suitable for

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printed circuits are common. The one in Pig. 6 shown embodiment the control disc is very advantageous to use where extreme speeds of rotation or strong temperature fluctuations are not expected in operational terms. Pure reliable Working with very strong fluctuations in the operating temperature, the control effect of a disc is sufficient According to Fig. 6 under certain circumstances, especially at the highest rotational speeds, not from.

Claims

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Claims (1)

_ 14 Claims 1.) Control value transmitter, which contains several electromagnetic components (11, 12), each of which has a core (44, 51) made of magnetic material and has a coil mounted on it, with aligned parts of the cores, their adjoining pole faces are moved away from each other in order to form a narrow air gap between them by shielding means (40,41,45,49,55,33), which each of the electromagnetic components spatially encompass and which the mutually facing end faces cover the electromagnetic components except for small, aligned openings (46, 50) by a movable one Control element (13) * that with part of its unit the air gap can be moved through and a number of relatively small parts (14,72) of its unit carries, which exert an effect on the positive transmission in the air gap that of the other parts of the control member is different, so that when the control member takes a position in which one of the small Teilu his Unit is located between the aligned openings in the shielding means, the inductive coupling - /, wipe olektroitn ^ netic components ρ Lo ta L loh is changed « ?.,) SteLLwertübortrager according to claim 1, characterized in that the> small parts (14, 72) on the movable control member (L 5) are made of conductive material / around the ο Flussüber rtra ^ un ¹ ; Ln the LuftnpaLt too 009852/0350. BAD sMfc ^: 3 ») control value transmitter according to claim 1, characterized in that that each spatially encompassing part (4o, 4l) of the shield has a longitudinal joint (42, 43) which is essentially Extends over the entire length of the coil and to the relatively small opening (46, 50) in the shield the pole face is aligned. 4.) control value transmitter according to claim 1, characterized in that the movable control member (Γ?) Has the shape of a has rotatable circular disc and in which the relatively small parts of the control member are made of conductive parts Material and uniform over the circumference of the control member are distributed,, 5 «) control value transmitter according to claim 1, characterized in that that the coil of one of the electromagnetic components (11) is excited by an alternating current source (15) and in to which the other electromagnetic component (12) is inductively coupled therewith, in a mass that is of ' depending on the position of the movable control element (IJ) is. 6.) control value transmitter according to claim 5, in which the magnetic core of the electromagnetic component (11) connected to the power source is smaller than the magnetic one Core of the other electromagnetic component (12), 7.) control value transmitter according to claim 5, characterized in that, 0098 5 2/03 5 0 BATH 1566711 net that the shielding means (53 * 45) of the with the power source connected electromagnetic component (ll) a transverse slot has, the one with the relatively small opening (46) converges in 4-way shielding of this electromagnetic component for the purpose of more precise control of the flux path. 8.) control value transmitter according to claim 1, characterized in that that the coil of one (ll) of the electromagnetic components is excited by a high frequency power source (15) and in which the coil of the other electromagnetic component (12) acts as a feedback element with the power source is connected for the purpose of output modulation of the current source according to the position of said movable Control element. 9.) control value transmitter according to claim 5, characterized in that the modulated output of the current source (15) demodulated and used in a trigger circuit (27) to generate pulses. 10.) control value transmitter according to claim 1, characterized by an additional shielding element (33) which forms the air gap bridged for the purpose of further narrowing the plus path between coils (11,12). 009852/0350 L e r s e i t e