Illumination – Supported by vehicle structure – Condition responsive
Reexamination Certificate
2001-06-12
2002-09-17
O'Shea, Sandra (Department: 2875)
Illumination
Supported by vehicle structure
Condition responsive
C362S464000, C362S466000, C362S467000
Reexamination Certificate
active
06450673
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a car head lamp auto-leveling system. The system automatically adjusts a tilt of an optical axis of a head lamp based on an inclination in the longitudinal direction of the vehicle (referred to as a “pitch angle” hereinafter) in the direction to cancel a corresponding variation in the pitch angle. More particularly, the auto-leveling system automatically adjusts the optical axis of the head lamp mainly based on the pitch angle of the standing vehicle.
The head lamp of this type has such a structure, for example, that the reflector into which the light source is inserted is fixed to the lamp body to be tilted from the horizontal tilting axis and also the optical axis of the reflector (head lamp) can be tilted from the horizontal tilting axis by the actuator.
The auto-leveling system in the prior art is constructed by providing a pitch angle detecting means, a speed sensor, a control portion for controlling the drive of the actuator based on detection signals supplied from them and the like, to the vehicle, and adjusts the head lamp such that the optical axis of the head lamp (reflector) is always set to a predetermined state to a road surface.
1
However, conventional auto-leveling systems are constructed to execute the leveling in real time in response to the change in the vehicle posture due to the acceleration/deceleration during the running and the load change, such as loading/unloading of the baggage during the stop state, having people get in and out of the vehicle, and the like, regardless of the running and the stopped state of the vehicle. Therefore, the actuator is operated very frequently which increases the consumption of power, and also great durability is required of the constituent parts of the driving mechanism such as the motor, the gears, etc. which causes an increase in cost.
Therefore, for the purpose of providing the auto- leveling system that can be used inexpensively for the long term by reducing the frequency in the drive of an actuator, an auto-leveling system was proposed which controls the drive of the actuator at a predetermined interval (e.g., 10 second interval) during the stop state, and controls the drive of the actuator only once in running as far as the vehicle is in a stable running state (Patent Application Publication (KOKAI) 2000-85458). Since a plurality of changes in the posture of the vehicle during a stop can be collected in one drive control of the actuator, the durability of the actuator can be improved.
However, according to the above proposed auto- leveling system, even if the vehicle posture is changed immediately after the drive of the actuator (immediately after the leveling), the next drive of the actuator (leveling) is performed after 10 seconds lapsed and thus the driver feels the delay. Thus, since there is no relevancy between the timing at which the vehicle posture is changed by people getting in and out of the vehicle, the loading/unloading of the baggage, etc. and the timing at which the actuator is operated (10 second interval), such leveling arouses a peculiar feeling in the driver.
Also, the pitch angle data used in the drive control of the actuator are the average pitch angle data in the moving time of 1 second (1-second average pitch angle data), for example. Therefore, if the vehicle posture is changed very rarely in the middle of 1-second average, first the actuator is operated once by the 1-second average pitch angle data, on which the change up to the middle is reflected, and then the actuator is operated after 10 seconds by the 1-second average pitch angle data, on which the all changes of the vehicle posture are reflected, whereby the optical axis correction is completed. In this case, the actuator is operated (the leveling is executed) twice for one change in the vehicle posture, which leads to the reduction in the durability lifetime of the actuator.
SUMMARY OF THE INVENTION
The present invention has been made in light of the above problems in the prior art, and provides a car head lamp auto-leveling system which can be used inexpensively for a long term by reducing the frequency of the drive of actuators, and which does not arouse an unpleasant feeling in the driver.
A car head lamp auto-leveling system according to the invention includes head lamps whose optical axis are tilted vertically relative to a vehicle body by a drive of an actuator; a controlling means for controlling the drive of the actuators; a speed sensing means for sensing a speed of a vehicle; a pitch angle detecting means provided to at least one of left and right sides of at least one of a front wheel suspension and a rear wheel suspension, for detecting a pitch angle of the vehicle; and a memory portion for storing pitch angle data of the vehicle detected by the pitch angle detecting means; wherein the controlling means calculates moving average pitch angle data during a predetermined moving time based on the pitch angle detected by the pitch angle detecting means and then stores the data in the memory portion, and also controls the drive of the actuators based on the moving average pitch angle data such that optical axes of the head lamps are always brought into a predetermined tilted state with respect to a road surface when the vehicle is stopped or when moving, and
wherein the controlling means calculates the moving average pitch angle data during a plurality of different moving times based on the pitch angles detected by the pitch angle detecting means, respectively, and then stores the pitch angle data in the memory portion, discriminates stopped and moving states of the vehicle based on an output of the speed sensing means, controls the drive of the actuators in the stopped state based on the moving average pitch angle data during a stable vehicle posture wherein the stable vehicle posture is a state below a reference value that continues for at least a predetermined time and is maintained after the difference between respective moving average pitch angle data collected during a plurality of different moving times is increased once to exceed the reference value, and controls the drive of the actuators in the running state based on the moving average pitch angle data collected during a stable vehicle moving state wherein the stable vehicle moving state is a state which has a speed of more than a predetermined value and an acceleration of less than a second predetermined value and which moving state is continued and is maintained for a predetermined time.
In another implementation, a car head lamp auto-leveling system according to the invention includes head lamps whose optical axis are tilted vertically relative to a vehicle body by a drive of an actuator; a controlling means for controlling the drive of the actuators; a pitch angle detecting means provided to at least one of left and right sides of at least one of a front wheel suspension and a rear wheel suspension, for detecting a pitch angle of the vehicle; and a memory portion for storing pitch angle data of the vehicle detected by the pitch angle detecting means; wherein the controlling means calculates moving average pitch angle data during a predetermined moving time based on the pitch angle detected by the pitch angle detecting means and then stores the data in the memory portion, and also controls the drive of the actuators based on the moving average pitch angle data such that optical axes of the head lamps are always brought into a predetermined tilted state with respect to a road surface when the vehicle is stopped or when moving, and
wherein the controlling means calculates the moving average pitch angle data during a plurality of different moving times based on the pitch angles detected by the pitch angle detecting means, respectively, and then stores the pitch angle data in the memory portion, and controls the drive of the actuators in both stop and running states of the vehicle based on the moving average pitch angle data collected during a stable vehicle posture wherein the stable vehicle posture is that
Takeuchi Hideaki
Toda Atsushi
Choi Jacob Y.
Fish & Richardson P.C.
Koito Manufacturing Co. Ltd.
O'Shea Sandra
LandOfFree
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