Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Patent
1998-03-19
2000-02-08
Paladini, Albert W.
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
1525016, 318443, 318445, 318471, 318472, B60L 100, B60L 300
Patent
active
060231076
DESCRIPTION:
BRIEF SUMMARY
STATE OF THE TECHNOLOGY
The invention is based on a switching arrangement for a wiper motor for windshield wiper arrangements with a time-dependent and temperature-dependent load monitoring, wherein the wiper motor can be actuated via a power switching element, in connection with a means for detecting the parking position of a wiper lever and a thereon dependent control of the power switching element. A known switching arrangement of this type for a wiper motor (DE 28 52 676 IC2) combines a switching stage dependent on the rotational speed and a switching stage dependent on the temperature. The switching stage dependent on the rotational speed compares the time intervals between the pulses depending on the rotational speed with a reference value and, in this case, is configured such that a switching element will trigger a switching signal for turning off the motor only if the rotational speed of the motor is very slow or the motor is blocked. Once the malfunction has been corrected, the wiper motor operation is started up again automatically by turning the switching element on and off periodically. The motor temperature is additionally monitored to avoid a long shut-down is period, designed to protect the motor, by sensing the voltage drop at the armature winding of the motor, and the switching element can thus be switched off via an additional switching stage. This occurs through a regular switching of a relay to alternate between a voltage source and a constant current source. If the constant current source is connected through the relay and via the motor to a ground, then the motor temperature is determined with the aid of the armature winding resistance. No motor temperature can be determined if the voltage source is connected through the relay and via the motor to a ground.
If several pulses are triggered with each wiping cycle, one disadvantage of the pulse detection depending on the rotational speed is that a reference value is necessary, which takes on varying values, depending on the angle position for the wiper lever, thus requiring an involved circuit. A further disadvantage is that the temperature of the switching arrangement itself is not monitored. Thus, if a semiconductor switch is used as power switching element, the power switching element is not protected against a thermal overload and thus is not protected against destruction.
Another disadvantage lies in the fact that it is not possible to simultaneously monitor the temperature and supply the motor with voltage. Thus, the motor must be shut down each time for the temperature monitoring, which increases wear and tear of the motor and shortens its service life.
SUMMARY AND ADVANTAGES OF THE INVENTION
The present invention provides an improved circuit arrangement for actuating a wiper motor for windshield wiper arrangements with a time-dependent and temperature-dependent load monitoring, wherein the circuit arrangement comprises: a wiper motor that can be actuated via a semiconductor power switching element that is controlled by a control unit that is responsive to a signal from a means for detecting the parking position of a wiper lever and, produces a thereon dependent control signal with time dependent monitoring of the power switching element; circuit means for monitoring a chip temperature of at least the semiconductor chip of the power switching element and for shutting down the power switching element when a threshold temperature is detected; and wherein, in order to protect the wiper motor against an overload and blocking, the control unit responds to a time-dependent load monitoring signal provided by the means for indicating the parking position when the chip-temperature monitoring means responds, and shuts down the wiper motor completely.
The arrangement according to the invention, has the advantage that the motor as well as the power switching element are protected through a chip-temperature monitoring against a thermal overload. It is therefore possible to omit a cooling of the semiconductor end stage and to use low-cost S
REFERENCES:
patent: 3573585 (1971-04-01), Taylor
patent: 3624477 (1971-11-01), Rieman
patent: 3919612 (1975-11-01), Ratzel et al.
patent: 4866359 (1989-09-01), Schmid et al.
Kunitz Norman N.
Paladini Albert W.
Robert & Bosch GmbH
Spencer George H.
LandOfFree
Circuit arrangement for controlling a wiper motor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Circuit arrangement for controlling a wiper motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Circuit arrangement for controlling a wiper motor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1683383