Electricity: motive power systems – Automatic and/or with time-delay means – Time or with time-delay means
Reexamination Certificate
1999-12-23
2001-10-02
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Automatic and/or with time-delay means
Time or with time-delay means
C318S465000, C318S283000
Reexamination Certificate
active
06297609
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an obstruction detecting method for use in a power window apparatus and a power window apparatus. More particularly the invention relates to an obstruction detecting method for use in a power window apparatus and a power window apparatus, capable of preventing an excessive pinching force from acting on an object pinched or caught in a power window, even in a case of cessation of a supply of two phase pulses (a two-phase pulse signal) from a pulse generating section coupled to a window opening and closing motor.
2. Description of the Related Art
Among power window apparatus which have been previously employed for opening and closing a window of a motor vehicle, there has been known a power window apparatus which detects the pinching of an object in the window, and for stopping or reversing the window opening and closing motor at the detection thereof.
In this type, a conventional power window apparatus is made up of, at a minimum, a motor for opening and closing a window, a motor driving section for driving the motor rotationally, a pulse generator for generating a pulse in the rotation of the motor, a micro control unit (MCU) for controlling the entire operation of the apparatus, and operating switches for opening/closing the window manually.
In the aforesaid conventional power window apparatus made to detect the obstruction, in response to an operation of any one of the operating switches, the micro control unit supplies a drive signal through the motor driving section to the motor to rotate the motor in the forward direction or in the reverse direction in accordance with the switch operation so that the window is driven in the opening direction or in the closing direction. On the rotation of the motor, the pulse generator coupled to the motor operates to output a pulse signal comprising pulses. At this time, the micro control unit calculates the interval between the edges of the pulse signal outputted from the pulse generator by counting a clock signal to obtain a motor torque value on the basis of the calculated pulse edge interval. This is used for comparing the obtained motor torque value with a reference median stored previously in its internal memory. If the motor torque value exceeds the reference median by a substantial amount, the micro control unit makes a decision that a pinching in the window has occurred, and immediately stops or reverses the rotation thereof.
Thus, the conventional power window apparatus and obstruction detection apparatus is designed such that the motor torque value is obtained on the basis of the pulse edge interval of two phase pulses outputted from the pulse generator to compare the motor torque value with a reference median, thereby making a decision on the occurrence
o occurrence of the pinching in the window.
However, the aforesaid power window apparatus creates the following problem. That is, since the decision on occurrence
o occurrence of the pinching therein is made after the detection of the pulse edges of pulses outputted from the pulse generator, in the case in which the motor is locked abruptly because a high-rigidity object is pinched in the window, the micro control unit cannot detect the pulse edges of the output pulses of the pulse generator so that difficulty is encountered in obtaining the pulse edge interval in the micro control unit, which leads to the difficulty of obtaining the motor torque value on the basis of the pulse edge interval. This causes a pinching force exceeding a reference value (a value calculated by adding a preset reference allowable value to the reference median) to act on the object pinched.
In addition, in the case of the aforesaid power window apparatus, there arises problem if there is no output of a pulse signal from the pulse generator or no transmission of the pulse signal to the micro control unit. For example, if a magnetic sensor built in the pulse generator gets out of order, if a cable for leading the pulse from the magnetic sensor to the micro control unit breaks down, or if a breakage or a contact failure of a cable connector installed on the pulse generator side or on the micro control unit side occurs. If the pulse signal outputted from the pulse generator does not reach the micro control unit at all, difficulty is experienced in calculating the pulse edge interval in the micro control unit so that the motor torque value is unobtainable on the basis of the pulse edge interval. Hence, if the pinching into the window occurs during this time, the detection thereof becomes impossible. Still additionally, in the case in which the pulse generator generates two phase pulses, if only the one phase pulse of the two phase pulses does not reach the micro control unit, although the micro control unit can obtain the pulse edge interval, the obtained pulse edge interval doubles approximately to the intended pulse edge interval and, accordingly, the motor torque value based on the pulse edge interval also doubles approximately so that, irrespective of no occurrence of the pinching into the window, a false detection representative of the occurrence pinching therein takes place.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been developed in view of such problems, and it is an object of the invention to provide an obstruction detecting method and a power window apparatus capable of preventing a pinching force exceeding a reference value from acting on an object pinched and of avoiding the occurrence of a malfunction even when a pulse edge interval of pulses to be outputted from a pulse generator is unobtainable.
In accordance with this invention, there is provided an obstruction detecting method and a power window apparatus comprising a motor for opening and closing a window through the use of a window driving mechanism, a motor driving section for driving the motor, a pulse generating section for generating pulses in connection with the rotation of the motor, a micro control unit for conducting the entire control and drive processing, a timer and a switch device for conducting opening and closing operations of the window manually, wherein the micro control unit obtains a corresponding obstruction decision time from a reference value based upon a characteristic value of the motor to update a time to be set in the timer whenever a pulse edge of the pulses enters the micro control unit and, when one pulse edge of the pulses arrives but the next pulse edge does not arrive before the elapse of the pinching decision as time set in the timer, makes a decision to the occurrence of an pinching in the window to stop the drive of the motor or rotate the motor in the reverse direction.
With this configuration, since the pinching decision time calculated from the reference value is set in the timer incorporated into the micro control unit whenever one pulse edge of a pulse signal outputted from the pulse generator arrives at the micro control unit, for example, even in the case in which the motor is locked suddenly because a high-rigidity object is pinched in the window so that the next pulse edge does not arrive at the micro control unit, at the elapse of the pinching decision time set in the timer, that is, at the time that an external force corresponding to the reference value based upon the motor characteristic value acts on the pinched object, the drive of the motor is ceased or the motor is driven in the reverse direction, which accordingly prevents an external force exceeding a force corresponding to the reference value based upon the motor characteristic value from working on the pinched object.
In addition, since the pinching decision time to be calculated from the reference value becomes slightly longer than the pulse edge interval of the pulse signal outputted from the pulse generator in a state of no occurrence of pinching, when one pulse edge comes therein to enable the setting of the pinching decision time and the next pulse edge arrives (is detected) within the pinching decision time, the timer
Sasaki Akira
Takahashi Jun
Alps Electric Co. ,Ltd.
Brinks Hofer Gilson & Lione
Leykin Rita
Nappi Robert E.
LandOfFree
Obstruction detecting method for the use in power window... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Obstruction detecting method for the use in power window..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Obstruction detecting method for the use in power window... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2562630