DE4229045A1 - Commutator motor speed, direction and angle sensor for vehicle sliding roof or electric window - extends segment of commutator to L=shaped track which runs along circumference of commutator, and has sliding contact for sensing voltage of extended track - Google Patents

Abstract

The motor has an electrically conductive track (10) provided by one of the commutator segments (66) and extending parallel to the commutator (6). The track has a length which is greater than the commutator period (t) and is scanned via a sliding sensor (101) to provide a momentary voltage value. The track may be open-ended or closed by abutting a further commutator segment, its ohmic resistance being greater than the ohmic resistance of a partial coil (57) of the motor armature winding (5). ADVANTAGE - Accurate and reliable detection of rotational speed, duration or angular position with min. complexity.

Description

The invention relates to a brushed commutator motor with a device for recording its speed, Direction of rotation and / or angle of rotation position according to the Oberbe handle of claim 1.  

With rotating or translatory moving parts of the unit, such as electrically adjustable window panes or sliding windows chern in motor vehicles, is often a pinch protection required. To implement a safe pinch protection is particularly accurate recording of the rotation number, direction of rotation and / or angle of rotation of the respective lige drive motor of interest, as by a Evaluation of these measured variables determine a risk of trapping and can be prevented if necessary.

It is known the speed and direction of rotation of a Rotary drive electrically offset by 90 ° using two arranged Hall sensors to determine. This becomes centric on the rotary drive axis connected to it in a rotationally fixed manner ner ring magnet arranged. When the ring magnet rotates the two are arranged on the circumference of the ring magnet Hall sensors each from a variable magnetic field enforced. The occurring on the two sensors Magnetic field changes in the Hall voltage are, for example using digital Hall sensors in two 90 ° electrical mutually offset binary pulse trains converted. By The speed can count the number of pulses per unit of time and by comparing the two pulse trains the direction of rotation of the rotary drive can be determined.

Furthermore, from DE-OS 40 38 284 AI a method and Device for detecting the position and the direction of movement tion of translationally or rotationally moving parts of a Unit known, a rotary drive in particular with a rotatably connected, coded disc is provided, the a predetermined number in groups  arranged marks, which is preferably magnetic are trained. The magnetized marks are made using tapped from a Hall sensor, with counting pulses in rotation Direction-coded pulse sequences or counting pulses with rotary direction-coded form derived and supplied to a computer leads. In this calculator are used to determine the Position of the unit part indicated the direction of rotation coded ordered or shaped counts depending on the direction code tion is added or subtracted while moving by comparing the frequencies of the pulse trains with before given frequency patterns is determined.

The invention is based on the object of brushing afflicted commutator motor of the type mentioned at the beginning To provide an accurate and reliable Detection of the speed, direction of rotation and / or angle of rotation enables with reduced effort.

This task is characterized by the characteristics of the Claim 1 solved.

The solution according to the invention results in a brush Commutator motor with a device for detecting its Speed, direction of rotation and / or angle of rotation position, the a very precise and reliable recording of the respective Measured variable guaranteed with reduced effort.

The invention is based on the knowledge that the in the Series connected sub-coils of the armature winding of a comm mutator motor induced a clear informa tion both over the speed and direction of rotation as well as over the angular position of the commutator motor  deliver if certain sub-coils intermittently abge are gripped and the respective tapping duration measured is that an incrementing or decrementing span is recorded.

The commutator motor according to the invention therefore has at least an essentially parallel to the commutator, electrically conductive and with at least one lamella of the Commutator connected scanning track, the length of which is greater than the commutator pitch, with each scan track one connected to the detection device and the moment value of the voltage of the scanning track detecting scanning element assigned.

A preferred embodiment of the solution according to the invention is that the scan track is part of a circle ring is formed, which is preferably in the circumferential direction ends openly. The length of the open trace is adapt to the respective requirements.

For example, with a view to being as exact as possible Direction of rotation or speed detection one track length ahead partially, which the rotor of the commutator motor with about 90 ° wraps up to 110 °. With such a degree of wrap result in the two possible directions of the Voltage signals clearly differing from each other, so that a sufficient signal-to-noise ratio for a flawless Signal evaluation is guaranteed.  

On the other hand, for the most accurate position detection possible Using a scan track with maximum wrap advantageous to maximize the voltage profile Liche circumferential area to be able to capture. Of the maximum wrap angle depends on the scan area of the respective scanning element.

As an alternative, however, the use is also more rer insulated, arranged one behind the other in the circumferential direction Neter traces possible, the z. B. only two comm Cover mutator lamellae so that one lamella having commutator six scanning tracks can be provided could.

Another advantageous embodiment of the invention Solution is that the scan track is closed is formed by adding another slat of the commutator is connected. This configuration enables light a differential voltage measurement that leads to a steeper The course of the voltage and thus deviate clearly from one another appropriate voltage signals, which leads to interference can improve the signal evaluation.

In this embodiment, it is also advantageous if the ohmic resistance of the scanning track is greater than the ohmic resistance of a partial coil of the armature winding, so that impairments to the motor properties are avoided. Preferably, therefore, the ratio of the resistances R _S / R _A <100, with R _S for the ohmic resistance of the sensing track and R _A for the ohmic resistance of the armature winding.

A simple and proven tap of the respective scan track can be done in that the scanning element from a there is sliding contact aligned with the scanning track.

Alternatively, the scanning element can also consist of one of the tracing track of galvanically separated voltage detection element exist. This will in particular be a mechanical wear of the scanning track and the scanning elements prevented.

A further advantageous embodiment is characterized records that several samples running parallel to each other tracks of different lengths are provided. Means this configuration allows the accuracy of the rotation increase number, direction of rotation and / or position detection, by comparing the detected voltage values and preferably be averaged.

According to a preferred embodiment of the invention Solution, the detection device consists of a device device for signal processing, an evaluation logic and a Device for outputting a signal for the direction of rotation and / or speed and / or angle of rotation position. Such a designed detection device enables a scarf tion and if necessary also a direction of rotation reversal of the commutator motor provided the detected voltage values or the derived speed, direction of rotation and / or angular position a pinching process or the Signal position.  

This would be, for example, an electrically adjustable one Window pane the case if this is according to the rotation angular position of the commutator motor not yet in your uppermost closed position, although the fens disc or the rotor of the commutator motor no longer or hardly moved despite the relatively high power supply.

Another advantageous embodiment of the invention be is that the detection device for fading of vibration-related interference signals at least one has electronic filter. This can signal malfunctions, for example as a result of mechanical Vibrations of the sliding contact and / or the rotor are caused, if necessary suppressed.

Further advantageous embodiments of the invention are in marked the subclaims. The invention will below based on the From shown in the drawing examples of management explained in more detail.

Show it:

Figure 1 is a schematic representation of a brushed commutator for translatory and / or rotationally moving unit parts.

Fig. 2 is a schematic representation of a developed commutator with a parallel, circumferential, open-ended scanning track;

Fig. 3 is a time representation of the tapped on the scanning track of FIG 2 voltage courses with left and right rotation of the commutator motor in motor operation.

FIG. 4 shows a time representation of the voltage curves tapped at the scanning track according to FIG. 2 with counterclockwise rotation and clockwise rotation of the commutator motor in generator operation;

Fig. 5 is a schematic representation of a developed commutator with a closed scanning track;

Fig. 6 is a time representation of the tapped on the tracing according to FIG 5 voltage curves with left and right rotation of the commutator motor;

Fig. 7a-7c are schematic illustrations of differently configured strobe tracks;

Fig. 8 is a schematic representation of a developed commutator with a closed scanning track and a voltage detection element arranged galvanically separated from the scanning track;

Fig. 9 is a time representation of a detected on the scanning track of FIG. 8 and waveform

Fig. 10 is a block diagram of a feed and control circuit for detecting the speed, direction and angle of rotation of a commutator motor.

Fig. 1 shows schematically a trained as a DC motor electric motor 1 with a rotor 2 and a stator 3rd The armature winding 5 of the rotor 2 is connected in a manner known per se to the sector-shaped, mutually insulated lamellae of a commutator 6 , one end of each two coils of the armature winding 5 being connected to a lamella of the commutator 6 . The armature current is supplied to the rotor 2 on the circumference of the commutator 6 via sliding contacts 7 , 8 , which preferably consist of graphite and are referred to below as brushes.

As is shown more clearly in the following figures, at least one lamella of the commutator 6 is connected to at least one electrically conductive scanning track 10 which runs essentially parallel to the commutator, each scanning track being associated with a scanning element 101 connected to a detection device.

The rotor 2 of the electric motor is also connected to a motor shaft 4 , which is formed in this embodiment as part of a worm gear. The motor shaft 4 drives the translationally or rotationally moving parts of an assembly 20 , which can consist, for example, of the transmission of a window lift device in motor vehicles. This transmission converts the rotary movement of the motor shaft 4 into a translatory movement for raising and lowering a window pane.

The electric motor 1 is connected to a plug connection 15 , which establishes a connection to a control device 17 , which at the same time contains a circuit for detecting the speed, direction of rotation and / or angle of rotation position of the electric motor 1 or of the unit part 20 . The control device used to control the motor or armature current also contains a supply circuit connected to the voltage source 14 .

The control device 17 is also connected to a switching device 18 , which has one or more switches with which the movement of the driven unit parts can be set or triggered in one direction or the other. For this purpose, the switches can consist of toggle or pushbutton switches which, when touched once, cause the movement of the assembly parts up to the end stop in one direction or the other or only cause movement as long as the switch in question is actuated.

The detection of the speed and / or direction of rotation of a commutator motor or a unit part mechanically connected to it will be described below with reference to FIGS. 2 and 3.

In Fig. 2, a developed commutator 6 is shown schematically, which has, for example, twelve mutually insulated lamellae. The slats are in the previously described manner with the coil sections of the armature winding 5 verbun. The current is supplied via two opposite, spring-loaded brushes 7 , 8 , which are arranged in a brush holder 70 which surrounds the commutator 6 in a ring.

One of the commutator lamellae 66 is connected to an electrically conductive scanning track 10 running parallel to the commutator 6 , the length (L) of which is greater than the commutator pitch (t), so that by means of a sliding contact 101 aligned with the scanning track 10 , the induced voltages are at least conditions two sub-coils of the armature winding 5 are tapped intermittently. The voltages recorded are related to ground potential.

If the length of the scanning track 10 approximately covers the circumference of three commutator lamellae, then during motor operation in which the torque and direction of rotation of the commutator motor run in the same direction, the temporal voltage curves shown in FIG. 3 result.

The voltage curve is made up of discrete chips blocks together, where the resolution depends on the number of the partial coils of the armature winding connected in series depends. It can be seen that in the above indicated NEN direction, which is referred to here as clockwise rotation, each Revolution results in a decrementing voltage curve, while in the opposite direction an increment render voltage curve occurs.

Based on the shape of the respective voltage curve thus clearly the direction of rotation of the commutator motor or  of a unit part driven with it determine what preferably in the Er described below Detection facility takes place.

In contrast, the speed of the commutator motor results from the periodic voltage curve, in that the respective period t _P1 or t _{P2 is} detected, for example, between the intermittently occurring voltage maxima. The reciprocal of the respective period corresponds to the speed of the commutator motor.

If, on the other hand, the commutator motor according to FIG. 2 is operated as a generator, which occurs, for example, when lowering a driving load and in particular also when the motor is switched off due to inertia-following, then a voltage curve deviating from FIG. 3 results in the corresponding running direction of the commutator motor.

If the generator operation occurs, for example, when the commutator motor runs counterclockwise, then, as shown in FIG. 4, there is a voltage reversal with an incremental negative voltage profile. The detection device connected to the scanning element therefore preferably has circuit elements which determine the amount of the voltage detected in each case, so that a sudden change in the operating mode of the commutator motor is evaluated by the speed and direction of rotation detection.

Fig. 5 shows schematically another embodiment in which, in addition to the developed commutator lamellae, a scanning track 10 'connected to two commutator lamellae 61 , 67 is arranged. The scanning track 10 ', which is preferably connected to two opposing commutator bars 61 , 67 , has a maximum wrap angle which is approximately 360 °, the remaining insulation being larger than the scanning area of the sliding contact 101 .

So that there is no significant influence on the motor properties, the closed scanning track 10 'with respect to the partial coils of the armature winding 5 is of high impedance. Before ohmic resistances are in a ratio of R _S / R _A <100, where R _S for the resistance of the sensing track 10 'and R _A for the resistance of a coil section 51 , 52 of the armature winding 5 .

As illustrated in FIG. 6, the connection of the scanning track with two commutator bars leads to the detection of the difference between the voltages induced in the partial coils of the armature winding.

The two span shown for clockwise and counterclockwise rotation The course of the voltage enables both the detection of the rotation number and angular position as well as the direction of rotation of the Commutator motor. The speed can be as in the previous one Embodiment based on the period of the sawtooth Determine moderate voltage curve. The direction of rotation can can be evaluated over the length of the scanning track by the Instantaneous values of the detected voltage with that for each rotation direction specified voltage curve are compared. The determination of the angular position, however, can in the respective direction of rotation based on the amplitude and the advance Chen be determined.  

To detect the angular position of the commutator motor it is also expedient to have an open-ended scanning track maximum wrap depending on the scanning area the sliding contact. Alternatively, is however, the use of several open, in scope direction of successively arranged scanning tracks purpose moderate, for example two slats of the commu cover tators. The angle of rotation position can then be based on the voltage amplitude, the position the fixed brushes serve as a reference point.

The accuracy of the detection of the angle of rotation position is as already indicated above, by the number of in series switched sub-coils of the armature winding determined.

Different configurations of the scanning tracks are shown schematically in FIGS. 7a to 7c.

Fig. 7a shows a developed representation of the scope of a commutator 6 , on which a plurality of mutually parallel de scanning tracks 11 , 12 , 13 are arranged with different lengths, which are electrically conductively connected together with a lamella 69 . Each of the scanning tracks is assigned its own scanning element, not shown in detail.

The outer scanning track 13 has a maximum wrap angle and is expediently used to detect the angle of rotation position. The inner scan track, however, only covers four slats and is therefore particularly suitable for the detection of the direction of rotation.

The commutator 6 shown in Fig. 7b is also provided with a plurality of mutually parallel, differently long scanning tracks 11 ', 12 ', 13 ', which are, however, each electrically connected to another lamella 65 , 67 , 69 of the commutator 6 . This embodiment offers the advantage that in the event of faults on a scanning track, the detection of the induced voltages or the measurement variables which can be derived therefrom is still ensured by the remaining scanning tracks.

In the exemplary embodiment shown in FIG. 7c, twelve commutator segments and three differently long scanning tracks 11 '', 12 '', 13 '' are arranged on a common cylindrical body, the scanning tracks being arranged one behind the other in the circumferential direction and each with a different segment 62 , 66 , 69 are connected.

The three scanning tracks 11 '', 12 '', 13 '', the track length of which increases or decreases stepwise depending on the direction of rotation, is assigned a single spring-loaded sliding contact. The gradation of the track lengths leads to a coded direction-dependent signal sequence which, in addition to the incrementing or decrementing voltage curve, enables additional detection of the direction of rotation.

In Fig. 8, another embodiment of a twelve-plate commutator 6 is shown schematically ben. The indicated partial coils 51 , 52 of the armature winding 5 and the commutator bars are again shown in a developed form.

The commutator 6 is provided with a scanning track 10 'in which two coils 31 , 32 of different lengths running parallel to the slats are arranged. The ends of the larger coil 31 , which wraps around the commutator 6 at almost 360 °, are connected to two opposite slats 61 , 67 , while the ends of the smaller coil 32 , which is arranged within the larger coil 31 , are also connected to one of these two opposite ones Slats and connected to an intermediate slat 64 .

The scanning track 10 'or the two coils 31 , 32 is assigned a scanning element which consists of a signal detection element 102 which is electrically isolated from the scanning track 10 '. In this case, a Hall sensor can be used as a scanning element, for example, which detects the signal change in the partial coils of the armature winding 5 or the change in the magnetic field occurring on the coils 31 , 32 and supplies a corresponding voltage signal.

A possible course of this voltage signal is shown in FIG. 9 for the exemplary embodiment described here. The connection of the ends of the sensor coils with various slats leads to a differential measurement of the voltages induced in the partial coils of the armature winding. The signal curve shown in FIG. 9 corresponds to the sum of the magnetic fields due to the superposition of the two sensor coils.

Using such a coded signal curve, the direction of rotation and the speed of the commutator motor clearly identify. The resolution of the angle of rotation position is comparatively high, even if the scanning element is above a rotation angle range of 120 ° el a constant signal detected.

Fig. 10 shows in the form of a block diagram a Einrich device for detecting the speed, direction and angle of rotation of a commutator motor.

The waveforms detected via a scanning element are first fed to a device 161 for signal processing within the detection device 16 , in which the detected signals are converted, for example, into absolute values, so that a voltage reversal taking place when changing from motor to generator operation does not result in an incorrect evaluation of the Waveforms leads.

In addition, the device 161 for signal processing is preferably equipped with active electronic filters with which vibration-related signal interference is masked out.

The detection device 16 also includes an evaluation telogic 162 , which determines the respective speed, direction of rotation and / or angle of rotation of the commutator motor from the previously processed signal profiles and forwards it to an output device 163 .

Furthermore, the existing preferably a microprocessor evaluation logic 162 a shutdown or reset signal to the control device 17 of the commutator motor, provided the detected voltage values or the speed derived therefrom, direction of rotation and / or angle of rotation of the commutator motor a pinching process or a position signali sieren.

The invention is not limited in its execution the above-mentioned embodiments. Much more a number of variants are conceivable, which are invented by the inventor Solution according to the invention even with fundamentally different types Make use of the remarks.

Claims (16)

1. Brushed commutator motor with a device for detecting its speed, direction of rotation and / or Drehwin kelstellung, characterized in that at least one lamella ( 66 ) of the commutator ( 6 ) with at least one substantially parallel to the commutator ( 6 ) extending, electrically conductive scan track ( 10 , 10 ') is connected, the length (L) is greater than the commutator pitch (t), and that each scanning track is connected to the detection device ( 16 ) and the instantaneous value of the voltage of the scanning track ( 10 , 10 ') detecting sensing element is assigned. 2. Commutator motor according to claim 1, characterized in that the scanning track ( 10 , 10 ') is formed as part of an annulus. 3. commutator motor according to claim 1 or 2, characterized in that the scanning track ( 10 ) ends open in the circumferential direction. 4. commutator motor according to claim 1 or 2, characterized in that the scanning track ( 10 ') is formed closed by it is additionally connected to another lamella ( 61 ) of the commutator ( 6 ). 5. Commutator motor according to claim 4, characterized in that the ohmic resistance of the scanning track ( 10 ') is greater than the ohmic resistance of a coil section ( 51 ) of the armature winding development ( 5 ) of the commutator motor ( 1 ). 6. commutator motor according to claim 4 or 5, characterized in that the ratio of the resistances R _S / R _A <100, where R _S for the ohmic resistance of the scanning track ( 10 ') and R _A for the ohmic resistance of a partial coil ( 51 ) the armature winding ( 5 ) is. 7. Commutator motor according to one of the preceding claims, characterized in that the scanning element consists of a sliding contact ( 101 ) aligned with the scanning track ( 10 , 10 '). 8. commutator motor according to any one of the preceding claims 1-6, characterized in that the scanning element consists of one of the scanning track ( 10 , 10 ') galvanically separated voltage detection element ( 102 ). 9. commutator motor according to one of the preceding claims, characterized in that the scanning track ( 10 , 10 ') and the fins of the commutator ( 6 ) are arranged on a common body. 10. Commutator motor according to one of the preceding claims, characterized in that a plurality of mutually parallel scanning tracks ( 11 , 12 , 13 ) of different lengths are provided. 11. commutator motor according to claim 10, characterized in that the plurality of scanning tracks ( 11 , 12 , 13 ) with a lamella ( 69 ) of the commutator ( 6 ) are electrically connected. 12. Commutator motor according to claim 10, characterized in that the plurality of scanning tracks ( 11 ', 12 ', 13 ') are each electrically conductively connected to a different lamella ( 65 , 67 , 69 ) of the commutator ( 6 ). 13. commutator motor according to one of the preceding claims, characterized in that several are separated from each other arranged scanning tracks of the same length are provided.   14. Commutator motor according to one of the preceding claims 1 to 12, characterized in that a plurality of scanning tracks arranged separately from one another ( 11 '', 12 '', 13 '') of different lengths are provided. 15. Commutator motor according to one of the preceding claims, characterized in that the detection device ( 16 ) from a device ( 161 ) for signal processing, evaluation logic ( 162 ) and a device ( 163 ) for outputting a signal for the direction of rotation and / or speed and / o the angle of rotation position exists. 16. commutator motor according to one of the preceding claims, characterized in that the detection device for At least suppression of vibration-related interference signals has an electronic filter.