EP1096087B1 - Motor vehicle door lock - Google Patents

Description

The invention relates to a motor vehicle door lock, with at least one electric motor drive, in particular central locking drive, and with an actuatable by the drive output device, such as. As transmission, output element, central locking lever, etc., wherein the drive is energized at least within a time interval required for adjusting the output device, wherein further the drive within or at the end of the time interval - (blockade) - (mechanically) is blocked, and wherein the Current supply of the drive and thus the torque and / or speed along at least one ramp is reduced or will be.

A motor vehicle door lock of the embodiment described above is treated in the context of EP 0 147 549 A2. This is about an electrical central locking device for motor vehicles, which is movable by one centrally controllable electromechanical actuator in one of two positions. From one of the actuators, an electrical position detector is actuated to switch off the actuator. The position detector or position transmitter is designed for the continuous detection of the positions of the actuator. Position signals of the position sensor are fed into means for forming a switching position of the actuator and in means for forming the time interval remaining to reach the next end position from the switching position. The current of the actuator after reaching the switching position can be controlled in dependence on the time interval.

In addition, a further predetermined position of the actuator following the switching position can be detected, from which the actuator is fed to reach the end position with a reduced current in the working direction. The associated motor of the actuator can be braked by a counter-current, not to the associated locking device abruptly into the new end position. - Current curves with arbitrary design can not be represented hereby.

This also applies to another known motor vehicle door lock with electromotive central locking. This consists in the present case of an electric motor, a transmission and an output element which engages in an associated locking kinematics of the above-described motor vehicle door lock (see DE 35 26 501 C2).

The electromotive central locking is energized via an electronic control within the aforementioned time interval, the Bestromungszeit to compensate for tolerances is longer than the time required to adjust the output device. In other words, here is the blockage time within the aforementioned time interval. In each case at the end of the positions "unlocked" and "locked" the known motor vehicle door lock thus runs against a stop. Since an energization takes place beyond this blocking time point, the entire output device is under mechanical tension, because the drive is subjected to the same amount of electrical energy and attempts to turn the output device further.

Due to the fact that the described components of the output device, in particular the gear or transmission parts, the output element and the associated stops in the housing are usually made of plastic, these behave elastically under the influence of the described mechanical stress. This applies a fortiori when the aforementioned blocking stops are integrated into the illustrated locking kinematics. Anyway arise in the prior art elastic stresses, from which the resulting problems to be explained below.

In addition, it is known to form an electromotive central locking as a separate unit. This unit can be mounted on the motor vehicle door lock and connected to the aforementioned lock kinematics via a rod. The blocking stops are in the locking kinematics. In this embodiment, the chain of elastic parts is increased again.

EP 0 528 317 A1 describes a control device in motor vehicles. This is used to set one of two end positions of an actuator via a control unit by means of two located between the actuator and the control unit control lines. This is done in response to a controller connected to the control switch with two arbitrarily adjustable switch positions, which are assigned to the end positions of the actuator. In the signals for adjusting the actuator can be used on pulse width modulated signals.

The US-PS 5 263 762 A deals with a motor vehicle with sliding door and associated closing sensor. In this case, too, a pulse width modulation is used.

In the prior art, the procedure is generally such that the energization of the electromotive drive is terminated immediately after the end of the time interval, so that the abovementioned mechanical stress is abruptly canceled in the described components. The elasticities shown are accordingly released, which results in a movement of these components by the path of elasticity plus unavoidable play within bearings and transmissions. This movement results in (unwanted) noises.

Because during operation, two distinctly perceptible noises are generated. The first sound becomes when reaching the end position (End stop or at blockage time) produced, while the second, (quieter) noise is generated later by switching off the current and the associated abrupt mechanical relaxation of the system. The former noise is usually desired and is expected by the user as feedback of the door-open status. On the other hand, no meaningful information can be assigned to the subsequent (usually quieter) noise, so that it is accordingly perceived as disturbing. - Here the invention aims to provide a total remedy.

The invention is based on the technical problem to further develop a motor vehicle door lock of the embodiment described above so that disturbing noises due to elasticities in the output device can be reliably avoided.

To achieve this object, the invention proposes in a generic motor vehicle door lock, that the energization of the drive pulse width modulated by means of current pulses given time and frequency, being operated until the beginning of the ramp with a predetermined maximum value of a duty cycle, further wherein the duty cycle along the ramp to is reduced to a minimum value of the duty cycle, and wherein the maximum value of the duty cycle is 100% and the minimum value of the duty cycle is 0%. In addition, the duty cycle along the ramp is usually reduced continuously to the minimum value.

As a consequence of this, first of all the energization of the drive and thus its torque and / or speed so that its torque and / or speed along a ramp - and not abruptly as in the prior art - reduced. Here, the invention is based on the recognition that the product of rotational speed and torque of the electromotive drive essentially corresponds to the (recorded) electrical power. A reduction of the torque and / or the rotational speed is thus accompanied by a minimized (electrical) power consumption and vice versa. The pulse width modulation takes place - as I said - by means of (square wave) current pulses of predetermined duration and frequency. Here you can work with certain duty cycles. This is the pulse width compared to the period to understand. A duty cycle of 100% thus corresponds to a (quasi) DC signal, while a duty cycle of 0% corresponds to no energization. This will be explained in more detail with reference to the description of the figures.

In any case, in the invention until the beginning of the aforementioned ramp with a predetermined maximum value of the duty cycle, 100% worked. This duty cycle is reduced along the relevant ramp up to the blockage of the drive or even beyond to a minimum value. This minimum value is 0%. Incidentally, the ramp is substantially continuous. It is also possible that the energization of the drive and thus the duty cycle - starting from the maximum value - along two linear ramps is reduced to the minimum value. Finally, the invention provides that the beginning of the ramp coincides with the blockage time of the drive in terms of time or lies ahead of it by a predetermined amount.

In any case, it is achieved in the context of the invention that the gentle shutdown of the energization of the drive causes a defined mechanical relaxation in the output device. The second disturbing noise thus does not arise, which is caused in the context of the prior art by the known, abrupt shutdown of the energization. Yes, it is even conceivable to completely suppress the described noises in the context of the present application. Such occurs when the beginning of the ramp is the blockade time in advance, namely the aforementioned measure, so that preferably the minimum value of the ramp and the blocking time coincide or at least not far apart in time.

The electric motor of the motor vehicle door lock described is usually controlled by means of a semiconductor (usually FET transistor) within the electronic control. In this way, the described method of pulse width modulation is easy to implement. In addition, commercially available microcontrollers hardware and software support a linear pulse width modulation control. It is always ensured that the linear torque deviation or absorption is easy to program due to the linear relationship between motor current or absorbed motor power and torque. Preferably, a pulse width modulation clock frequency of 15 kHz or more is used, so that the control itself does not generate an audible sound level.

Fig. 1

einen erfindungsgemäßen Kraftfahrzeugtürverschluß in schematischer Ansicht,

Fig. 2

ein Zeitdiagramm, wie es im Stand der Technik realisiert wird,

Fig. 3

die erfindungsgemäße Schaltung zur Ansteuerung des elektromotorischen Antriebes in schematischer Ansicht,

Fig. 4

verschiedene eingesetzte Tastverhältnisse zur Pulsweitenmodulation und

Fig. 5

einen Zeitverlauf, wie er im Rahmen der Erfindung realisiert wird.

In the following the invention will be explained in more detail with reference to a drawing showing only one embodiment; show it:

Fig. 1

a motor vehicle door lock according to the invention in a schematic view,

Fig. 2

a timing diagram, as realized in the prior art,

Fig. 3

the circuit according to the invention for controlling the electromotive drive in a schematic view,

Fig. 4

different duty cycles for pulse width modulation and

Fig. 5

a time course, as it is realized in the context of the invention.

In the figures, a motor vehicle door lock is shown, which has an electric motor drive 1. This acts together with a gear 2, 3 and works on a linearly adjustable output element 4. This output element 4 engages in a unspecified locking kinematics in the form of a transmission lever 5 with other levers connected. In any case, can be using the transmission lever 5 and the connected lever realize a central locking, as described in detail in the introductory already mentioned German Patent 35 26 501 is described, to which reference is expressly made.

The drive 1 is energized at least within a time interval Z required for adjusting the output device 2, 3, 4, 5, as shown in principle in FIG. 2. Here, three time courses can be seen among each other, namely the movement of the drive 1 in the upper part, the current carried out during the time interval Z, d. H. a current / time diagram, and finally the noise associated with the known approach, i. H. a - if you like - volume / time diagram.

It can be seen that the energization begins with the start time AZ, which of course coincides with the beginning of the movement of the drive 1. According to the prior art, the drive 1 runs after a certain time against a stop not explicitly shown, namely at the blockage time BZ. As a result, a first noise G1 occurs. Since the energization in the prior art is continued until the end time EZ after the time interval Z, it comes to the described elasticities in the output device 2, 3, 4, 5. If at the end time EZ the energization abruptly eliminated, there is a second Noise - G2 - a, which is to be avoided according to the invention.

For this purpose, according to the illustration in FIG. 5, the procedure is that of the torque curve shown over time t having the shown design. It can be seen that the drive 1 is energized during the entire time interval Z, but the energization and the torque resulting therefrom have a different course than in FIG. 2. In fact, virtually until the blockage time BZ with a certain torque and thus a predetermined electrical power to pressurize the drive 1 is worked. Thereafter, the energization of the drive 1 and thus its torque along a ramp shown R ₁ , R ₂ , R _{3 is} reduced.

In detail, the energization of the drive 1 is pulse width modulated, as shown in principle in FIG. 4. In this case, the upper part of Fig. 4 shows a duty cycle ^t / _T of about 50%, which also corresponds to an approximately 50% torque application of the drive 1 because of the linear dependence of the electrical power or the current and the torque. In the lower part of FIG. 4, a duty ratio ^t / _T of approximately 80% (corresponding to approximately 80% of the maximum possible torque) is shown.

By adjusting the duty cycle ^t / _T can thus be the torque curve of FIG. 5 represent easily. It is up to the beginning of the ramp R ₁ , R ₂ , R ₃ with a maximum value, 100% (for the duty cycle ^t / _T and thus the torque) worked. This duty cycle ^t / _T is reduced along the ramps R ₁ , R ₂ , R ₃ , until the minimum value, 0%, is reached. According to the embodiment are - starting from the maximum value (100%) - three linear Ramps R ₁ , R ₂ and R ₃ realized. They start at the blockage time BZ, but may also be earlier by a predefined measure M. However, this is not expressly shown.

Of course, only one ramp R ₁ or two ramps R ₁ , R ₂ can be used. In addition, of course, four (or more) ramps R ₁ , R ₂ , R ₃ , etc. conceivable. In any case, the duty cycle ^t / _T along these ramps R ₁ , R ₂ and R _{3 is} reduced to the end time EZ (0% of the torque or the duty cycle ^t / _T ). The supply voltage, of course, remains constant during this time.

Finally, in Fig. 3, the basic structure of the electronic circuit for controlling the electric motor drive 1 can be seen. This has a microprocessor 6 in conjunction with a plurality of transistor / diode elements 7. The microprocessor 6 specifies the direction for the drive 1 and also the duty ratio ^t / _T and thus the shape of the ramp R ₁ , R ₂ , R ₃ .

Claims (4)

1. Motor vehicle door lock, having at least one electromotive drive (1), in particular central locking drive (1), and having an output device (2, 3, 4, 5) which can be acted upon by the drive (1), such as e.g. transmission (2, 3), output element (4), central locking lever (5) etc., wherein

   - the drive (1) is energised at least during a time interval (Z) which is needed to adjust the output device (2, 3, 4, 5), wherein further

   - the drive (1) is blocked during or at the end of the time interval (Z) - at the blocking time (BZ), and wherein

   - energising the drive (1) and therefore the torque and/or speed thereof is respectively are reduced along at least one ramp (R₁, R₂, R₃),

   characterized in that

   - energising the drive (1) is carried out in pulse-modulated fashion by means of current pulses of given duration (t) and frequency (1/T), wherein

   - a given maximum of a duty cycle (t/T) is used up to the start of the ramp (R₁, R₂, R₃), wherein further

   - the duty cycle (t/T) along the ramp (R₁, R₂, R₃) is reduced to a minimum value of the duty cycle (t/T), and wherein

   - the maximum value of the duty cycle (t/T) is 100% and the minimum value of the duty cycle (t/T) is 0%.
2. Motor vehicle door lock according to claim 1, characterized in that the duty cycle (t/T) along the ramp (R₁, R₂, R₃) is reduced continuously up to the minimum value.
3. Motor vehicle door lock according to claim 1 or 2, characterized in that energising the drive (1) and therefore the duty cycle (t/T) - starting with the maximum value - is reduced along at least two linear ramps (R₁, R₂, R₃) up to the minimum value.
4. Motor vehicle door lock according to one of the claims 1 to 3, characterized in that the start of the ramp (R₁) coincides in time with the blocking time (BZ) of the drive (1) or precedes it by a given measure (M).

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