Illumination – Light source and modifier – Condition responsive
Reexamination Certificate
1999-10-14
2001-10-23
Sember, Thomas M. (Department: 2875)
Illumination
Light source and modifier
Condition responsive
C362S464000, C362S465000, C362S467000
Reexamination Certificate
active
06305823
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an automatic leveling device for automotive vehicle headlamps for controlling the driving of optical axis tilt adjusting actuators based on an inclination in a longitudinal direction of a vehicle (hereinafter, referred to as a pitch angle). A pitch angle detection means detects and automatically tilt adjusts the optical axes of the headlamps (hereinafter, referred to as automatic leveling) in a direction to offset an angle corresponding to the detected pitch angle. In addition, the automatic leveling device includes a fail safe function that automatically stops driving the optical axis tilt adjusting actuators should they happen to fail.
Known automatically adjustable headlamps include a reflector having a light source securely inserted therein and supported in such a manner as to be tilted around a horizontal tilt shaft relative to a lamp body. The optical axis of the reflector (headlamp) is tiltable around the horizontal tilt shaft by means of an actuator. A conventional automatic leveling device includes a pitch angle detection means, a vehicle speed sensor, a controlling section for controlling the driving of an actuator based on signals from the detection means and sensor, and the like, all of which are mounted on a vehicle. The optical axes of the headlamps (reflectors) are adjusted so as to stay in a certain state with respect to the surface of the road at all times.
In the conventional automatic leveling device, however, no countermeasures are provided against a failure of the actuators. Thus, if the actuators fail and become inoperable, the optical axes of the headlamp are fixed in the position where they were directed when the actuators failed. If the optical axes are fixed as being directed more upwardly than a desirable level, although the driver of the subject vehicle can get good visibility, a driver of an oncoming vehicle will be dazzled by the light from the headlamps. Conversely, if the optical axes are fixed as being directed too low, although there is no problem for oncoming vehicles, the visible distance is shorter and may cause the driver to detect an object on the road too late, thus putting the driver into a dangerous situation.
SUMMARY OF THE INVENTION
The present invention provides an automatic leveling device for automotive vehicle headlamps, wherein if one of the actuators for automatically leveling the optical axes fails, the failing actuator is automatically stopped from being driven, while the actuator that is operating normally is used to restore as close to a proper leveling state as possible.
An automatic leveling device for automotive vehicle headlamps includes a pair of left and right headlamps whose optical axes are tilted individually vertically relative to a vehicle body through driving of left and right actuators, respectively. A single control unit simultaneously controls the driving of the left and right actuators. A vehicle speed detection means detects the speed of the vehicle, and a pitch angle detection means detects the pitch angle of the vehicle. The control unit controls the driving of the actuators based on a detected pitch angle such that the optical axes of the headlamps stay in a certain inclined state with respect to the surface of a road. A failure detection means is provided for each of the actuators that detect a failure thereof, whereby when a failure is detected in either of the actuators by the failure detection means, driving of only that failed actuator is stopped.
The optical axis of the headlamp having the failing actuator is fixed to a predetermined position, which is different from a desirably proper position because the driving control of the actuator is stopped. But since leveling of the other headlamp is properly performed, the degree of reduction in the visible distance for the driver is reduced, and glaring light directed at an oncoming vehicle is reduced.
The invention may include one or more of the following features. The automatic leveling device may include a control unit that determines, based on a signal from said failure detection means, whether or not the actuators fail, respectively, and wherein when determining that either of the actuators fails, the control unit outputs a driving stop signal to the failed actuator to stop driving the actuator. Since the control unit determines whether or not the actuators fail and stops driving the actuators, the number of constituent components of the automatic leveling device is reduced, and the construction thereof is simplified. The actuator may include a motor as an actuator main body, position detection means for detecting the driving magnitude of the motor, and a motor driver for feedback controlling the driving of the motor based on a signal from the position detection means. Since the motor driver built in the actuator feedback controls the motor, the quantity of information processed by the control unit is reduced. Therefore, the load on the control unit is reduced as well, whereby the number of functions demanded from the control unit is reduced.
The actuator may include a driving stop circuit for stopping driving of the motor, whereby when the failure detection means detects a failure in said actuator, the driving stop circuit is put into operation. When the motor is detected as failing by the failure detection means, the driving stop circuit is started to operate so as to stop the motor. In other words, the actuators themselves are provided with a fail safe function, and the number of functions required of the control unit is reduced accordingly.
Further, the automatic leveling device may include indicator means for informing the driver that either of the actuators is failing when the failure detection means so detects. The indicator means informs the driver that automatic leveling is not functioning properly.
A mode of operation of the invention will be described with reference to embodiments.
REFERENCES:
patent: 3177355 (1965-04-01), Trowbridge
patent: 3385961 (1968-05-01), Lemberger
patent: 4188655 (1980-02-01), Tallon et al.
patent: 4845598 (1989-07-01), Watanabe et al.
patent: 5195816 (1993-03-01), Moss, Jr. et al.
patent: 5787370 (1998-07-01), Kutscher et al.
patent: 5877680 (1999-03-01), Okuchi et al.
patent: 6109759 (2000-08-01), Tanabe et al.
“HID System with Adaptive Vertical Aim Control”, Society of Automotive Engineers, Inc. (1998) pp. (13-18).
Takeuchi Hideaki
Toda Atsushi
DelGizzi Ronald E.
Fish & Richardson P.C.
Koito Manufacturing Co. Ltd.
Sember Thomas M.
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