DE102007041798A1 - Drive for an adjustment of a motor vehicle - Google Patents

Abstract

The invention relates to a drive for an adjusting device of a motor vehicle, having a rotatably mounted drive shaft, with a multi-pole magnet arranged on the drive shaft as a signal generator for generating magnetic signals, with a sensor for detecting the magnetic generated by the signal generator during a rotational movement of the drive shaft Signals and with magnetic Signalleitmitteln, with which the magnetic signals from the signal generator can be conducted to the sensor. In this case, the individual magnetic poles (21, 22) of the signal generator (2) along the circumferential direction of the drive shaft (10) spaced from each other are arranged one behind the other, so that between two magnetic poles (21, 22) each have a gap (23) is provided.

Description

The The invention relates to a drive for an adjusting device of a motor vehicle according to the preamble of claim 1.

One such a drive comprises a (driven by a motor) rotatable mounted drive shaft, one arranged on the drive shaft multi-pole magnet as a signal generator and a sensor for detection the generated by the signal generator during a rotational movement of the drive shaft magnetic Signals. Furthermore, signal conducting means are provided, which are the signals from the signal generator in the form of a multi-pole magnet generated magnetic signals forward to the sensor.

Such a drive is from the DE 197 55 337 A1 known, according to which the multipolar magnet is formed by a rotatably mounted on the drive shaft Polrad and the Signalleitmittel consist of a magnetically conductive material.

Of the Invention is based on the problem, a drive of the beginning mentioned type with regard to the transmission of magnetic Signals from the signal transmitter in the form of a multi-pole magnet to the associated To improve sensor.

To One aspect of the invention addresses this problem by the features of claim 1.

After that are the individual poles of serving as a signal generator multipole Magnets along a drive shaft annularly encompassing Circumferential direction one behind the other and thereby spaced from each other arranged. As a result, serving as a signal generator multipolar Magnet a Polrad whose magnetic poles along the circumferential direction not directly adjacent to each other but in the circumferential direction adjacent magnetic poles each by a gap from each other are separated.

A Such training of serving as a signal generator multipolar magnet has the advantage that in the forwarding of the multipole magnetic signal generator generated by magnetic signals provided for this purpose (magnetic) Signalleitmittel (in Shape of flux guides) the possible magnetic short-circuit region is reduced. Instead of a usual sinusoidal course the magnetic multipole magnet generated as a signal generator Signals thus results in a more step-shaped, rectangular-like (quasi-digital) waveform in the manner of a square wave signal.

to Minimization of magnetic short-circuit areas is the mean angular spacing adjacent magnetic poles of the signal generator, for example in Essentially as large as the average angular extent the magnetic pole in the circumferential direction.

If Here are the existing of a magnetically conductive material Signal conducting means for detecting the magnetic signal with their the signal transmitter associated end portions along the circumferential direction the signal generator z. B. each extend with the same angular extent like the magnetic poles and the gaps between neighboring ones magnetic poles, then that can be the magnetic Signals forming, with a rotation of the drive shaft temporally variable Magnetic field of the multi-pole magnet of the Signalleitmitteln comprising and thereby detect essentially short-circuit-free. Can do this further along the circumferential direction of the magnetic signal transmitter successively arranged end portions of the Signalleitmittel respectively have an angular distance from each other, which is substantially the angular extent the end portions of the Signalleitmittel and the angular extent the poles and gaps on the signal generator corresponds.

Around under such conditions as to the (limited) angular extent the magnetic poles of the signal transmitter and the magnetic poles associated end portions of the signal conducting the magnetically effective Surfaces on the signal transmitter and on the end sections of the Signaling means interpreted sufficiently large, can a correspondingly large extent of the multi-pole magnet trained signal generator and the associated end sections the Signalleitmittel in the axial direction, ie along the extension direction be provided the drive shaft.

To In another aspect of the invention, the signal routing means, with which the magnetic field lines generated by the rotating signal generator or the associated magnetic flux to the associated Sensor, in particular a Hall sensor, is passed, according to claim 11 is a kind of magnetic lens, the magnetic field lines for Sensor points out so that the field lines the sensor with high concentration, ie high magnetic flux density, push through.

For this can the sensor-facing end portions of the Signalleitmittel, z. B. as constituents of each Flussleitstückes, in pairs so inclined to each other that they face the sensor forming acute angles; and in those end sections may continue a cross-sectional constriction to increase the magnetic Flow density can be provided.

Furthermore, it is expedient to use magnetic materials (flux-conducting materials) for the signal-conducting means. to use with high permeability and with the Signalleitmitteln a conclusion to opposite magnetic poles of the multi-pole magnet to form, so that together with the sensor, a (closed) magnetic circuit is formed.

Of the Drive can in particular an adjusting device of a motor vehicle drive, adjusted with the position of an adjustment of the motor vehicle is, such. B. a window of a motor vehicle, a Seat part of a motor vehicle seat or an adjustable armrest.

Further Details and advantages of the invention will become apparent in the following Description of an embodiment with reference to the figures clearly become.

It demonstrate:

1a a perspective view of a drive of a Kraftfahrzeugverstelleinrichtung with a arranged on a drive shaft of the drive magnetic pole as a signal generator and an associated sensor and with signal transmission means by which signals generated during rotation of the magnetic pole wheel are passed to the sensor;

1b a second perspective view of the arrangement 1a ;

2a the arrangement of the 2a and 2 B together with a housing for receiving the sensor;

2 B a cross section through the arrangement 2a in the area of the housing.

In the 1a and 1b such as 2a and 2 B are from a drive 1 a Kraftfahrzeugverstelleinrichtung one on a drive shaft 10 (Motor shaft) mounted rotor 12 in the form of an anchor and an axial behind the rotor 12 provided commutator 14 shown. For more details on the design of such a well-known electric motor drive, z. B. in terms of the motor housing and the stator, is exemplary of the DE 197 55 337 A1 directed.

In order to operate such a drive 1 the speed and the angle of rotation of the drive shaft rotating about its longitudinal axis 10 to be able to determine is on the drive shaft 10 rotatably a multi-pole magnet in the form of a pole wheel 2 arranged, the present four magnetic poles 21 . 22 of which two poles 21 as magnetic south poles S and two poles 22 exist as magnetic north poles N. Here are the magnetic poles 21 . 22 the poll wheel 2 here along the circumferential direction U of the pole wheel (which the drive shaft 10 surrounds) each arranged at a distance from each other. That is, along the circumferential direction U of adjacent magnetic poles 21 . 22 are not immediately adjacent to each other, but are each through one between adjacent poles 21 . 22 provided gap 23 separated from each other.

A respective gap 23 is here as a recess of the pole wheel 2 formed, the adjacent magnetic poles 21 . 22 does not separate along its entire radial extent, but - starting from the outer edge 26 of the pole wheel - up to a central area 25 of the pole wheel 2 , about this at the drive shaft 10 is fixed. Based on 1a . 1b such as 2a . 2 B It can be seen that the respective gap designed as a recess 23 between adjacent magnetic poles 21 . 22 of the pole wheel 2 in the radial direction R over a substantial part of the pole wheel 2 extends, specifically in the embodiment over more than half of the extent of the pole wheel in the radial direction R, compare 2 B ,

Upon rotation of the drive shaft 10 during operation of the electromotive drive 1 this creates together with the drive shaft 10 rotating pole wheel 2 at a given location in each case a time-varying magnetic field, ie magnetic signals from a sensor provided at that location, designed here as a Hall sensor 4 , detected and an evaluation can be supplied to speed and rotation angle of the drive shaft 10 to investigate.

The angular extent W2 of the gaps 23 between adjacent magnetic poles 21 . 22 is here substantially the same size or at least of the same order of magnitude as the angular extent W1 of the individual magnetic poles 21 . 22 in the circumferential direction U. In the present embodiment, all poles have 21 . 22 of the pole wheel 2 as well as between the poles 21 . 22 lying gaps 23 each have the same geometry and the same spatial dimensions and are each formed mirror-symmetrically with respect to a central, radially extending straight line. In practice, however, the design of the magnetic poles 21 . 22 and / or gaps 23 of the pole wheel 2 slightly different from that regular structure to allow a sense of rotation, so to be able to determine whether the drive shaft 10 during operation of the drive 1 Turn clockwise or counterclockwise. In this case, the above statements apply to the mean (averaged) angular expansions W1, W2. Furthermore, if appropriate, a plurality of sensors 4 for the detection of the pole wheel 2 be generated signals to hereby determine the angle of rotation can.

As with a synopsis of 1a and 1b with the 2a and 2 B becomes clear, here is a respective Hall sensor as a so-called SMD component ("surface mounted device" / "surface mountable component") on a support board 50 in the form of a printed circuit board in a housing 5 (Socket housing) arranged from the electrical connections 55 in the form of contact pins for those on the carrier board 50 stand out arranged electrical and electronic components. The said electrical and electronic components can in addition to at least one Hall sensor 4 Furthermore, components include, for example, for processing and / or evaluation of the Hall sensor 4 used output signals are used.

The signal from the transmitter in the form of a pole wheel 2 generated magnetic signals in the form of a time-varying magnetic field are from the associated sensor in the form of a Hall sensor 4 not directly in the area of the outer edge 26 of the pole wheel 2 but the Hall sensor 4 is at some distance, in particular radial distance, from the pole wheel 2 arranged; and they are signal or flux guiding means 3a . 3b in the form of two of a magnetically conductive material, for. B. from highly permeable soft iron, existing Flussleitstücke 3a and 3b provided to the pole wheel 2 generated magnetic signals, more precisely, the magnetic field lines of the flywheel 2 generated time-varying magnetic field or the associated magnetic flux, to the Hall sensor 4 to lead.

The two flux conductors 3a . 3b extend substantially radially with respect to the pole wheel 2 with a comparatively smaller extension component in the axial direction A and are arranged side by side along the circumferential direction U and spaced from each other.

Each of the two flux guides 3a . 3b each has a basic body 30 on, the advantage of a magnetically conductive material of high permeability, such as. B. soft iron, and is located between a first, the pole wheel 2 associated and facing end portion 31 and a second, the Hall sensor 4 associated and facing end portion 32 extends.

The flux guides 3a . 3b are at their the pole wheel 2 facing first end portions 31 each angled so that they are with their angled first end portions 31 each along the circumferential direction U of the pole wheel 2 extend. In this case, a minimum air gap MS between the outer edge 26 of the pole wheel 2 and the pole wheel 2 facing surface of the respective end portion 31 the flux guides 3a . 3b sought; and the pole wheel 2 facing, first end portions 31 the flux guides 3a . 3b extend in the circumferential direction U substantially over the same angular range W3 as the magnetic poles 21 . 22 of the pole wheel 2 (as well as between the poles 21 . 22 provided gaps 23 ). This should as possible the entire, of a respective magnetic pole 21 . 22 of the pole wheel 2 generated magnetic field, so its magnetic field lines - with appropriate position of the pole wheel 2 concerning the flux conducting pieces 3a . 3b as in the 1a to 2 B shown - from an associated end portion 31 a respective flux guide 3a . 3b receivable and as a magnetic flux to the Hall sensor 4 be forwarded.

In this case, the angular extent W3 of the first end sections should 31 the flux guides 3a . 3b preferably not be greater than the angular extent W2 of the gaps 23 between the magnetic poles 21 . 22 along the circumferential direction U to magnetic shorting zones and short circuit times during the movement of the pole wheel 2 along the associated first end portions 31 . 32 the flux guides 3a . 3b to minimize. For an enlargement of the magnetically effective surface during interaction of the pole wheel 2 with the associated end sections 31 the flux guides 3a . 3b Under such boundary conditions, a corresponding increase in the extent L, I of the pole wheel offers 2 and the associated first end portions 31 the flux guides 3a . 3b in the axial direction A on.

Furthermore, the angular distance W4 between the (adjacent) first end portions 31 the two flux conductors 3a . 3b in the circumferential direction U possible not substantially smaller than the angular extent W2 of the gaps 23 of the pole wheel 2 along the circumferential direction U to magnetic short circuits along the Flussleitstücke 3a . 3b to avoid. For this reason, the Flussleitstücke point 3a . 3b also along their respective elongated body 30 in each case a sufficient distance from each other, the only in the area of the Hall sensor 4 facing second end portions 32 will be annulled.

Overall, with the separation of the magnetic poles 21 . 22 of the pole wheel 2 along the circumferential direction U through gaps 23 and with the spacing of the flux guides 3a . 3b from each other and with the choice of the angular extent of the magnetic poles 21 . 22 , the gaps 23 , the first end sections 31 and from which distance the greatest possible reduction or minimization of magnetic short-circuit zones and times are achieved.

That from the first end sections 31 the flux guides 3a . 3b in the area of the outer edge 26 of the pole wheel 2 upon rotation of the pole wheel 2 recorded magnetic signal under these conditions corresponds more to a (digital) square wave signal as a sinusoidal curve.

The at a rotational movement of the drive shaft 10 from the signal generator in the form of a pole wheel 2 generated, at a certain point in space each time-varying magnetic field lines are of the pole wheel 2 associated first end portions 31 the flux guides 3a . 3b because of the minimized air gap MS between the outer edge 26 of the pole wheel 2 and those end sections 31 and because of the optimized angular expansions W1, W2, W3, W4 (arc dimensions) as completely as possible and with minimization of magnetic short circuits detected and then in radially (and with an axial component) elongated body 30 the respective flux guide 3a . 3b to the Hall sensor 4 guided. By using a high-permeability, magnetically conductive material for the flux guides 3a . 3b , z. B. of soft iron, the transmission of the magnetic flux from the pole wheel 2 associated first end portions 31 to the Hall sensor 4 associated second end portions 32 the flux guides 3a . 3b largely loss and saturation done. Of course, depending on the requirements of the information content and the evaluation of the signal generator in the form of a pole wheel 2 generated magnetic signals more than two flux guides 3a . 3b and / or more than one Hall sensor 4 be provided.

The Hall sensor 4 is from the second end portions facing it 32 the flux guides 3a . 3b separated by a working air gap AS, wherein those second end portions 32 with their free ends towards a surface 40 of the Hall sensor 4 point. The two flux conductors 3a . 3b make with their the Hall sensor 4 facing second end portions 32 a magnetic lens, by means of which the magnetic flux density by focusing the magnetic field lines in those end portions 32 increases (maximizes) ("magnetic converging lens") and thus concentrates the Hall sensor 4 is supplied, which - by suitable choice of the working air gap AS - advantageous in the focal point of the second end portions 32 the flux guides 3a . 3b formed magnetic lens is located.

To achieve the described lens effect, the second end portions extend 32 the two flux conductors 3a . 3b inclined to one another in such a way that they form an acute angle α, tending to that Hall sensor 4 running towards each other obliquely, wherein at the same time the distance between the two Flussleitstücken 3a . 3b (significantly) reduced.

An increase in the flux density in the second end sections 32 the flux guides 3a . 3b is further to achieve that the material thickness d and / or the width b (here expansion along the axial direction A) of the flux guide 3a . 3b in the region of their second end portions 32 is reduced. In other words, the cross section of the flux guide is 3a . 3b in the region of their second end portions 32 compared to other, adjacent areas of flux guides 3a . 3b reduced (cross-sectional constriction).

The second end sections 32 the flux guides 3a . 3b are the Hall sensor 4 facing with their free ends, so each run on a facing surface 40 of the Hall sensor 4 to and are - unlike the first end sections 31 - not angled so that they extend along a surface of the Hall sensor.

The exact geometric design and spatial arrangement of the second end sections 32 , including the choice of the extent of the cross-sectional constriction and the inclination angle α and the size of the working gap AS is to be set in each case so that a desired concentration of the magnetic field lines at the Hall sensor 4 is reached.

Here are the Flussleitstücke 3a . 3b in the present case further arranged and configured such that (together with the Hall sensor 4 ) - with appropriate angular position of the pole wheel 2 A closed magnetic circuit between opposite magnetic poles 21 . 22 of the pole wheel 2 can form.

Furthermore, in particular by way of 2 B recognizable that the flux guides 3a . 3b in this case, for receiving the Hall sensor 4 , the carrier board 50 and optionally further electrical and electronic components serving housing 5 are integrated, so from a part of that housing 5 being held. The flux guides 3a . 3b can in particular also with the carrier board 50 be firmly connected.

In summary, in the case of the 1a and 1b such as 2a and 2 B illustrated embodiment of an electric motor drive 1 with one through a flywheel 2 formed signal generator and one through a Hall sensor 4 formed receiver as well as with the signal transmission serving Signalleitmitteln in the form of Flußleitmittel 3a . 3b the magnetic short circuit ranges and short circuit times by a geeigne te shape design and arrangement of the pole wheel 2 and the flux guide 3a . 3b reduced or minimized. By reducing the short circuit zones and times, the magnetic signal of the pole 2 forming, time-varying magnetic field lines even in the case of strong signals without major losses at the Hall sensor 4 be provided, the field line density also for high speeds of the drive shaft 10 and thus the pole wheel 2 remains largely stable.

Furthermore, by suitable design of the pole wheel 2 facing first end portions 31 the flux guide 3a . 3b and by minimizing the local air gap MS as far as possible detection of the rotating rotor 2 achieved generated, time-varying magnetic field lines; and the magnetic flux associated therewith becomes (substantially in the radial direction) via short flow paths and as lossless as possible by using high permeability flux conducting materials to the Hall sensor 4 directed. There are the flux guides 3a . 3b with their second ends 32 is shaped and spatially arranged in such a way that the magnetic flux density and, accordingly, the concentration of the magnetic field lines is increased (maximized) and consequently the Hall sensor is permeated by a magnetic field with a high field line concentration, ie a high flux density. So are as large as possible shares of the pole wheel 2 actually generated magnetic signal to the Hall sensor 4 and recorded by it.

To increase the flux density also contributes that the flux guides 3a . 3b together with the Hall sensor 4 and the pole wheel 2 (by magnetic inference) form a (closed) magnetic circuit.

Another manipulated variable to achieve the strongest possible magnetic signal is the remanence of the magnetic pole wheel 2 by using suitable materials for the pole wheel 2 can be increased.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19755337 A1 [0003, 0021]

Claims (30)

Drive for an adjusting device of a motor vehicle, comprising - a rotatably mounted drive shaft, - a multi-pole magnet arranged on the drive shaft as a signal generator for generating magnetic signals during rotation of the drive shaft, - a sensor for detecting the magnetic generated by the signal generator during a rotational movement of the drive shaft Signals and - Signalleitmitteln of a magnetically conductive material, with which the magnetic signals from the signal generator to the sensor can be conducted, characterized in that the individual magnetic poles ( 21 . 22 ) of the signal generator ( 2 ) along the circumferential direction (U) of the drive shaft ( 10 ) are arranged one behind the other so that between two magnetic poles ( 21 . 22 ) each have a gap ( 23 ) is provided. Drive according to claim 1, characterized in that a respective gap ( 23 ) of the signal generator ( 2 ) from its outer edge ( 26 ) towards a central area ( 25 ) of the signal generator ( 2 ), over which the signal transmitter ( 2 ) on the drive shaft ( 10 ) is arranged. Drive according to claim 1 or 2, characterized in that the gaps ( 23 ) to the outer edge ( 26 ) of the signal generator ( 2 ) are open. Drive according to one of the preceding claims, characterized in that the magnetic poles ( 21 . 22 ) and gaps ( 23 ) of the signal generator ( 2 ) regularly along the circumferential direction (U) of the signal generator ( 2 ) are arranged. Drive according to one of claims 1 to 3, characterized in that in the arrangement of the magnetic poles ( 21 . 22 ) and / or gaps ( 23 ) of the signal generator ( 2 ) along the circumferential direction (U) is provided such an irregularity that based on the magnetic signals generated by the signal generator, the direction of rotation of the drive shaft ( 10 ) can be determined. Drive according to claim 5, characterized in that the irregularity is due to the geometry and / or spatial extent (W1, W2) of the magnetic poles ( 21 . 22 ) and / or gaps ( 23 ) is defined. Drive according to one of the preceding claims, characterized in that the mean angular extent (W2) of the gaps ( 23 ) along the circumferential direction (U) of the signal generator ( 2 ) at least half of the mean angular extent (W1) of the magnetic poles ( 21 . 22 ) along the circumferential direction (U). Drive according to claim 7, characterized in that the mean angular extent (W2) of the gaps ( 23 ) along the circumferential direction (U) of the signal generator ( 2 ) at least 80% of the mean angular extent (W1) of the magnetic poles ( 21 . 22 ) along the circumferential direction (U). Drive according to one of the preceding claims, characterized in that the mean angular extent (W2) of the gaps ( 23 ) along the circumferential direction (U) of the signal generator ( 2 ) substantially equal to the mean angular extent (W1) of the magnetic poles ( 21 . 22 ) along the circumferential direction (U). Drive according to one of the preceding claims, characterized in that the signal transmitter ( 2 ) is formed as an at least four-pole magnetic pole wheel. Drive for an adjusting device of a motor vehicle, comprising - a rotatably mounted drive shaft, - a multi-pole magnet arranged on the drive shaft as a signal generator for generating magnetic signals during rotation of the drive shaft, - a sensor for detecting the magnetic generated by the signal generator during a rotational movement of the drive shaft Signals and - Signalleitmitteln of a magnetically conductive material, with which the magnetic signals from the signal generator to the sensor can be conducted, in particular according to one of the preceding claims, characterized in that the Signalleitmittel ( 3a . 3b ) in at least one of the sensors ( 4 ) facing end portion ( 32 ) are formed such that within the Signalleitmittel ( 3a . 3b ) upon rotation of the drive shaft ( 10 ) due to the signal generator ( 2 ) generated magnetic signals extending magnetic field lines on the sensor ( 4 ). Drive according to Claim 11, characterized in that the signal-conducting means ( 3a . 3b ) are formed such that the density of the magnetic field lines and thus the magnetic flux density within the Signalleitmittel ( 3a . 3b ) to a respective sensor ( 4 ) facing end portion ( 32 ) increases. Drive according to one of the preceding claims, characterized in that the signal-conducting means ( 3a . 3b ) by at least two separate flux guides ( 3a ; 3b ) are formed, each consisting of a magnetically conductive material and which are arranged spatially spaced from each other. Drive according to claim 13, characterized in that the flux guide pieces ( 3a ; 3b ) along the circumferential direction (U) of the signal generator ( 2 ) are arranged side by side. Drive according to claim 13 or 14, characterized in that the flux guides ( 3a ; 3b ) each have an end portion ( 32 ) on the sensor ( 4 ). Drive according to claim 11 or 12 and claim 15, characterized in that end sections ( 32 ) of adjacent flux guides ( 3a ; 3b ) at an acute angle (α) inclined to each other, so that the distance between the two flux guides ( 3a ; 3b ) towards the sensor ( 4 ) tapers. Drive according to one of Claims 11 to 16, characterized in that the signal-conducting means ( 3a . 3b ) in its at least one, the sensor ( 4 ) facing end portion ( 32 ) a cross-sectional constriction compared with farther from the sensor ( 4 ) remote areas ( 30 ) of the signal conducting means ( 3a . 3b ) exhibit. Drive according to one of claims 13 to 16 and claim 17, characterized in that the cross-sectional constriction by reducing a material thickness (d) and / or a width (b) of a respective end portion ( 32 ) of the flux guides ( 3a ; 3b ) is formed. Drive according to one of the preceding claims, characterized in that the signal-conducting means ( 3a . 3b ) at a respective the signal transmitter ( 2 ) facing end portions ( 31 ) are angled so that they extend along the circumference (U) of the signal generator ( 2 ). Drive according to one of claims 13 to 16 and claim 19, characterized in that the flux guide pieces ( 3a ; 3b ) each one the signal transmitter ( 2 ) facing end portion ( 31 ), with which they are at the outer edge ( 26 ) of the signal generator ( 2 ) and extend along the circumferential direction (U). Drive according to claim 19 or 20, characterized in that between a respective the signal transmitter ( 2 ) facing end portion ( 31 ) of the signal conducting means ( 3a . 3b ) and the outer edge ( 26 ) of the signal generator ( 2 ) a gap (MS) is provided so that the respective end portion ( 31 ) of the signal conducting means ( 3a . 3b ) in the radial direction (R) of the signal generator ( 2 ) is slightly spaced. Drive according to one of Claims 19 to 21, characterized in that the signal-conducting means ( 3a . 3b ) with a respective end section ( 31 ) over an angle (W3) along the circumferential direction (U) of the signal generator ( 2 ) which is at most as large as the average angular extent (W2) of the gaps ( 23 ) of the signal generator ( 2 ) along the circumferential direction (U). Drive according to one of Claims 19 to 22, characterized in that the signal-conducting means ( 3a . 3b ) with a respective end section ( 31 ) over an angle (W3) along the circumferential direction (U) of the signal generator ( 2 ), which is substantially the same size as the average angular extent (W1) of the magnetic poles ( 21 . 22 ) of the signal generator ( 2 ) along the circumferential direction (U). Drive according to one of claims 19 to 23, characterized in that the angular distance (W4) adjacent, the signal generator ( 2 ) facing end portions ( 31 ) of the signal conducting means ( 3a . 3b ) along the circumferential direction (U) is at least as large as the average angular extent (W1) of the magnetic poles ( 21 . 22 ) of the signal generator ( 2 ) along the circumferential direction (U). Drive according to claim 11 or any one of claims 12 to 24, when dependent on claim 11, characterized in that between the sensor ( 4 ) facing end portions ( 32 ) of the signal conducting means ( 3a . 3b ) and the sensor ( 4 ) a gap (AS) is provided so that the said end sections ( 32 ) of the signal conducting means ( 3a . 3b ) from the sensor ( 4 ) are spaced. Drive according to one of the preceding claims, characterized in that the signal-conducting means ( 3a . 3b ) consist of a highly permeable magnetically conductive material, for example, soft iron. Drive according to one of the preceding claims, characterized in that the signal-conducting means ( 3a . 3b ) together with the signal transmitter ( 2 ) and the sensor ( 4 ) form a magnetic circuit. Drive according to one of the preceding claims, characterized in that the sensor ( 4 ) is formed as a Hall sensor. Drive according to one of the preceding claims, characterized in that the drive ( 1 ) drives an adjusting device of a motor vehicle, with which the position of an adjusting part of the motor vehicle is adjusted. Drive according to claim 29, characterized in that the adjusting part through a window disc of a motor vehicle, a seat part of a motor vehicle seat or an adjustable armrest is formed.