Window lifter for a vehicle and method for operating such a window lifter

Abstract

For the purpose of realizing an operationally reliable window lifter (opener) for a vehicle, there is provision to ascertain from an operating variable of a servomotor in each case a measure of a regulated position of the window pane in the course of a plurality of operating cycles of the window lifter in which a window pane of the vehicle is opened and closed again, in each case entirely or partly. In each operating cycle, or at least in selected operating cycles, the measure is normalized to a reference value if at the end of the respective operating cycle the window pane is driven by the servomotor for at least a predetermined blocked time beyond a blocked position. The blocked time is shortened if the normalization was not carried out for a predetermined number of consecutive operating cycles.

Claims

1. A method for operating a window lifter, which comprises the steps of: repeatedly actuating a window pane in a plurality of operating cycles by an actuator of the window lifter, wherein in each of the plurality of operating cycles, the window pane is entirely or partly opened and closed again; during the operating cycles, monitoring an operation variable of the actuator, and calculating a logical position based on the operating variable, wherein the logical position is a measure of a mechanical position of the window pane; in each operating cycle or at least in selected operating cycles, monitoring a movement of the window pane and normalizing the logical position to a reference value upon determining that at an end of a respective operating cycle, the window pane is continued to be driven by the actuator for at least a duration of a predefined blocking time after the window pane has reached a blocking position and using the normalized position of the window pane for controlling an automatic actuating operation with the window lifter.

2. The method according to claim 1, which further comprises shortening the predetermined blocked time, continuously or multiple times in predetermined stages, in dependence on a predetermined number of consecutive operating cycles in which the normalization was not carried out.

3. The method according to claim 1, which further comprises closing the window pane via the actuator only for a duration of a regulating command generated by user interaction via a command initiator.

4. The method according to claim 1, which further comprises registering an angle of revolution or a rotational speed of the actuator by way of an operating variable of the actuator on a basis of a rotation-direction-invariant measuring signal.

5. The method according to claim 4, wherein by way of the rotation-direction-invariant measuring signal, a signal of a single Hall-effect sensor is used, the signal interacting with an annular magnet coupled with a motor shaft of the actuator.

6. A window lifter for a vehicle, comprising: a actuator for reversible adjustment of an window pane of the vehicle between an open state and a closed state; and a control unit for driving said actuator, said control unit being configured for: repeatedly actuating a window pane in a plurality of operating cycles by said actuator of the window lifter, wherein in each of the plurality of operating cycles, the window pane is entirely or partly opened and closed again, during the operating cycles, monitoring an operation variable of the actuator, and calculating a logical position based on the operating variable, wherein the logical position is a measure of a mechanical position of the window pane, in each operating cycle or at least in selected operating cycles, monitoring a movement of the window pane and normalizing the logical position to a reference value upon determining that at an end of a respective operating cycle, the window pane is continued to be driven by the actuator for at least a duration of a predefined blocking time after the window pane has reached a blocking position, and using the normalized position of the window pane for controlling an automatic actuating operation with the window lifter.

7. The window lifter according to claim 6, wherein said control unit is configured to shorten the predefined blocking time, continuously or multiple times in predetermined stages, in dependence on a predetermined number of consecutive operating cycles in which the normalization was not carried out.

8. The window lifter according to claim 6, wherein said control unit is configured to drive said actuator, at least for the closing of the window pane, only for a duration of a regulating command generated by user interaction via a command initiator.

9. The window lifter according to claim 6, wherein said control unit is configured to use an angle of revolution or a rotational speed of said actuator by way of the operating variable of said actuator on a basis of a rotation-direction-invariant measuring signal.

10. The window lifter according to claim 9, wherein said actuator has a motor shaft; further comprising an annular magnet; and further comprising a single Hall-effect sensor which interacts with said annular magnet, coupled to said motor shaft of said actuator, for generating the rotation-direction-invariant measuring signal.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is an illustration showing a track-guided window lifter with an electric actuator, with a control unit, and also a window pane of a vehicle, coupled to the actuator via a servomechanism according to the invention; and

(2) FIG. 2 is a simplified flowchart for explaining a method for operating the window lifter.

DETAILED DESCRIPTION OF THE INVENTION

(3) Parts and variables corresponding to one another are always provided with the same reference symbols in all the figures.

(4) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown schematically a regulating device in the form of a track-guided window lifter 1 for a (vehicle) window pane 2 of a motor vehicle.

(5) The window lifter 1 includes an electric actuator 3 which is mechanically coupled to the window pane 2 via a servomechanism 4 in such a manner that the window pane 2 is reversibly displaceable by the actuator 3 along a displacement path 5 between two end positions, namely an open position xO and a closed position xC.

(6) FIG. 1 shows the window pane 2 in the open position xO and in the closed position xC, in each case with dashed outlines. The window pane 2 is represented by a continuous outline in an arbitrary intermediate regulated position x between the two end positions. In a data-processing sense, the open position xO and the closed position xC may be interpreted as constant numeric variables. The closed position xC, which in the example represented has been chosen to be identical to the upper blocked position of the window pane 2, is assigned the value zero (xC=0), by way of example. The open position xO is assigned a positive value (xO>0), by way of example. The regulated position x may in this case be interpreted as a variable that may assume values between xC and xO (xC≦x≦xO).

(7) The servomechanism 4 includes a drive worm 7 mounted on a motor shaft 6 of the actuator 3, which drive worm 7 meshes with a worm wheel 8. The servomechanism 4—indicated in FIG. 1 only in greatly simplified form—acts on a sliding carriage 9 which is guided on a guide track 10 and to which, in turn, the window pane 2 is fixed.

(8) The regulating device 1 furthermore includes a control unit 12 and also a rotary-position sensor 13. The rotary-position sensor 13 includes a multi-polar annular magnet 14 mounted on the motor shaft 6 in a rotationally fixed fashion, and also a Hall-effect sensor 15 interacting with the magnet. During the operation of the actuator 3, the annular magnet 14, rotating together with the motor shaft 6 relative to the Hall-effect sensor 15, generates, through interaction with the Hall-effect sensor 15, a periodically oscillating pulse signal SH which is supplied as an input variable to the control unit 12 by the Hall-effect sensor 15. In this connection the control unit 12 calculates, by counting the (Hall-effect) pulses of the pulse signal SH, a variable proportional to the number of rotations of the motor shaft 6 during a regulating operation, which in the following is designated as the angle of revolution φ. By summation of the angle of revolution φ with a stored value x′.sub.0 of the initial position of the window pane 2, the control unit 12 calculates a time-dependent measure of the regulated position of the window pane 2, which is designated in the following as the logical regulated position x′:
x′(t)=x′.sub.0+c.Math.φ(t),  Eqn. 1.

(9) The parameter c in Eqn. 1 stands for an empirically established constant of proportionality.

(10) The Hall-effect sensor 15 is a single Hall-effect sensor which provides the pulse signal SH as a rotation-direction-invariant variable. The angle of revolution φ, determined by counting the Hall pulses, consequently always has a positive value, irrespective of the direction of rotation of the actuator 3. For the purpose of determining the logical regulated variable x′, the control unit 12 presets the parameter c with a positive or negative sign, depending on the direction of rotation assumed by it.

(11) The control unit 12, in addition, drives the actuator 3 by outputting a motor current I. In the case of the regulating device 1, for safety reasons no automatic running in the closing direction and no prevention of jamming have been implemented. In the course of a major movement of the window pane 2 in the closing direction the control unit 12 consequently drives the actuator 3 only for the period in which a user of the vehicle actuates a corresponding operating push-button 16. However, the control unit 12 executes minor movements of the window pane 2, in particular a brief thrust, automatically without interaction with the user of the vehicle.

(12) In order to prevent the deviation of the logical regulated position x′ from the mechanical regulated position x as a consequence of counting errors, in the course of each operating cycle of the window lifter 1 the control unit 12 carries out the method described in the following on the basis of FIG. 2. In the control unit 12, which is formed substantially by microcontrollers, the functionality for carrying out the method automatically is implemented by software engineering.

(13) A cycle of the method—corresponding to an operating cycle of the window lifter 1—begins, according to FIG. 2, in a step 20 with the reception of an opening command O given by the user of the vehicle via the operating push-button 16 (FIG. 1).

(14) In a step 21 the control unit 12 checks, by monitoring the pulse signal SH, whether the actuator 3 is still rotating. So long as this is the case (Y), step 21 is repeated by the control unit 12, continuously or at defined time-intervals.

(15) Otherwise (N), i.e. if the actuator 3 is stationary, the control unit 12 checks, in a step 22, whether according to the logical regulated position x′ the window pane 2 has again arrived sufficiently close to its closed position xC by virtue of the fact that the user of the vehicle has in the meantime closed the window pane 2 by outputting a closing command C (FIG. 1) by means of the operating push-button 16. In this connection the control unit 12 checks, in concrete terms, whether the logical regulated position x′ falls short of a predetermined threshold value. This threshold value is preferably chosen in such a way that—given sufficient agreement of the logical regulated position x′ with the mechanical regulated position x—the upper edge of the window pane 2 has been spaced apart from the upper window seal by a maximum of 4 mm.

(16) So long as this condition has not been satisfied (N), the control unit 12 takes this as an indication that the ongoing operating cycle has not yet been concluded, and returns to step 21.

(17) Otherwise (Y)—that is to say, if the control unit 12 establishes that the actuator 3 is stationary (step 21), and if the window pane 2 is located close to its closed position xC (step 22)—the control unit 12 checks, in a step 23, whether the actuator 3 is still being supplied with current (I>0).

(18) If this is the case (Y), the control unit 12 takes this as an indication that the window pane 2 has reached its upper blocked position. In this case, the control unit 12 increments, in a step 24, a timer variable that specifies the time elapsed after the blocked position was reached. Subsequently the control unit checks, in a step 25, whether this timer variable (and consequently the time elapsed after the blocked position was reached) has reached or exceeded a predetermined blocked time. So long as this is not the case (N), the control unit 12 returns to step 21.

(19) Otherwise (Y), the control unit 12 takes the reaching of the upper blocked position as confirmed and re-normalizes, in a step 26, the logical regulated position x′ by setting the latter to the value zero (x′=0), and concludes the method cycle in a step 27.

(20) If, after the return from step 25, the check performed in step 21 turns out to be positive (Y), or the check performed in step 22 turns out to be negative (N), the control unit 12 assumes that the blocked state was abandoned before the blocked time was reached, and resets the timer variable to zero.

(21) If, on the other hand, the check performed in step 23 turns out to be negative (N), the control unit 12 infers therefrom that the actuator 3 was switched off before the blocked time was reached. In this case, the control unit 12 increments, in a step 28, a counter variable that specifies the number of successive operating cycles without normalization of the logical regulated position x′. Subsequently the control unit 12 checks, in a step 29, whether the value of the counter variable has reached or exceeded a predetermined limiting value.

(22) So long as this is not the case (N), the control unit 12 concludes the method cycle (step 27) without further action.

(23) Otherwise (Y), the control unit 12 reduces, in a step 30, the predetermined value of the blocked time. By way of example, in this connection the blocked time is reduced from the original 300 ms to 200 ms if the counter variable exceeds the value 10. Subsequently the control unit 12 once again concludes the method cycle (step 27).

(24) The method cycle that has been described is executed again with each operating cycle of the window lifter 1. If the blocked time is not reached over several consecutive operating cycles here, the counter variable is increased correspondingly. As soon as the blocked time is reached in a following operating cycle, the counter variable is reset to zero in the course of the normalization (step 26) and, where appropriate, the blocked time is reset to its original value of, for example, 300 ms.

(25) In a variant of the method, the check performed in step 29 and the subsequent reduction of the blocked time (step 30) have a multi-stage structure, with the result that the blocked time is shortened successively in a plurality of stages as a function of the counter variable. By way of example, in this connection the blocked time is reduced from the original 300 ms to 200 ms if the counter variable exceeds the value 10, and is reduced further to 100 ms if the counter variable exceeds the value 20.

(26) In an alternative method variant, the blocked time is reduced continuously, for example linearly, as the value of the counter variable increases.

(27) The invention becomes particularly clear with reference to the embodiment described above but is nonetheless not restricted thereto. Rather, numerous further embodiments of the invention can be deduced from the claims and from the above description.

(28) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 1 Window lifter 2 (Vehicle-) window pane 3 Actuator 4 Servomechanism 5 Displacement path 6 Motor shaft 7 Drive worm 8 Worm wheel 9 Sliding carriage 10 Guide track 12 Control unit 13 Rotary-position sensor 14 Annular magnet 15 Hall-effect sensor 16 Operating push-button 20-30 Step x (Mechanical) regulated position xO Open position xC Closed position x′ (Logical) regulated position SH Pulse signal φ Angle of revolution I Motor current x′.sub.0 Initial position O Opening command C Closing command