U.S. patent application number 13/242286 was filed with the patent office on 2012-01-19 for headlight optical axis adjustment device.
This patent application is currently assigned to OMRON CORPORATION. Invention is credited to Toshinori Origane, Akinobu Todani.
Application Number | 20120014122 13/242286 |
Document ID | / |
Family ID | 40044174 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120014122 |
Kind Code |
A1 |
Todani; Akinobu ; et
al. |
January 19, 2012 |
HEADLIGHT OPTICAL AXIS ADJUSTMENT DEVICE
Abstract
The present invention aims to perform optical axis adjustment
while a vehicle is stopped only in necessary situations and to
avoid unnecessary adjustment, and to further enhance durability. A
headlight optical axis adjustment device for adjusting an optical
axis of a headlight based on a pitch angle of the vehicle includes
an opened/closed state detection section for detecting an
open/closed state of an open/close unit where the opened state is
when a passenger gets on/out or when a baggage is being
loaded/unloaded to and from the vehicle; and an optical axis
adjustment permitting section for permitting optical axis
adjustment of the headlight based on the pitch angle of the vehicle
when the opened state of the open/close unit is detected by the
opened/closed state detection section.
Inventors: |
Todani; Akinobu; (Iida,
JP) ; Origane; Toshinori; (Iida, JP) |
Assignee: |
OMRON CORPORATION
Kyoto
JP
|
Family ID: |
40044174 |
Appl. No.: |
13/242286 |
Filed: |
September 23, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12241315 |
Sep 30, 2008 |
|
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13242286 |
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Current U.S.
Class: |
362/465 |
Current CPC
Class: |
B60Q 2300/14 20130101;
B60Q 2300/116 20130101; B60Q 1/10 20130101; B60Q 2300/132
20130101 |
Class at
Publication: |
362/465 |
International
Class: |
B60Q 1/04 20060101
B60Q001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 1, 2007 |
JP |
257966/2007 |
Claims
1. A headlight optical axis adjustment device for adjusting an
optical axis of a headlight based on a pitch angle of a vehicle;
the headlight optical axis adjustment device comprising: an
opened/closed state detection section for detecting an
opened/closed state of an open/close unit where the opened state is
when a passenger gets in/out or when a baggage is being
loaded/unloaded to and from the vehicle; and an optical axis
setting section for prohibiting the optical axis adjustment of the
headlight based on the pitch angle of the vehicle when the opened
state of the open/close unit is detected by the opened/closed state
detection section, and setting the optical axis of the headlight to
a predetermined angle so as not to dazzle the drivers of oncoming
vehicles and pedestrians.
2. The headlight optical axis adjustment device according to claim
1, further comprising: a behavior detection section for detecting a
behavior change of the vehicle necessary for calculating the pitch
angle; wherein the optical axis setting section sets the optical
axis of the headlight to the predetermined angle so as not to
dazzle the drivers of oncoming vehicles and the pedestrians when
the opened state of the open/close unit is detected by the
opened/closed state detection section, and a detection value of the
behavior detection section is greater than a predetermined value.
Description
PRIOR APPLICATIONS
[0001] This application is a divisional of and claims the benefit
of co-pending U.S. patent application Ser. No. 12/241,315, filed on
Sep. 30, 2008, titled "Headlight Optical Axis Adjustment Device",
and is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates to a headlight optical axis
adjustment device also referred to as "auto levelizer" used in
vehicles such as an automobile.
[0004] 2. Related Art
[0005] According to provision of safety standard (Department of
Transportation Law No. 67, Jul. 28, 1951) of Road Trucking Vehicle
Law, vehicles such as automobiles (hereinafter referred to as a
vehicle) must be provided with a "running headlight" (so-called
high beam) and a "passing headlight" (so-called low beam), or a
"light distribution variable headlight" which is a combination of
the above (combination of high beam and low beam).
[0006] The "running headlight" is provided to check obstructions in
terms of traffic at a front side of the vehicle at night, and the
"passing headlight" is provided, in addition to such requirement,
such that an irradiating light beam does not inhibit other traffics
(i.e., not to dazzle the drivers of oncoming vehicles and
pedestrians).
[0007] Although such "running headlight" and "passing headlight"
are respectively independent lighting tools, most of the recent
vehicles include the "light distribution variable headlight", that
is, a headlight for automatically adjusting luminosity of the
irradiating light beam and spatial distribution in a relevant
direction according to a traveling state at night, and thus the
description will be made herein using the "light distribution
variable headlight" by way of example. It should be noted that such
lighting tools are not distinguished in the concept of the
invention.
[0008] A driver switches the optical axis of the headlight to
either "high beam" or "low beam" depending on the situation when
traveling the vehicle at night. Specifically, the driver switches
to "high beam" to have the optical axis of the headlight to an
upper side (more precisely, horizontal) so as to be able to see
sufficiently well the distance in a situation where oncoming
vehicles or pedestrians are not present, whereas the driver
switches to "low beam" to have the optical axis of the headlight
slightly to a lower side so as not to dazzle the drivers of
oncoming vehicles and pedestrians in a situation where oncoming
vehicles or pedestrians are present.
[0009] The brightness and the optical axis of the headlight are
test objects of automobile inspection, where an irradiation
distance of high beam is generally adjusted to about 100 m towards
the front of the vehicle body, and the irradiation distance of low
beam is adjusted to about 40 m, and in particular, in a recent high
luminance headlight (typically using a metal halide lamp, and
normally referred to as an HID lamp), the demand on the adjustment
of the bright and dark boundary line (also referred to as a cutoff
line) of the beam distribution (particularly low beam) is becoming
stricter as even slight optical axis shift greatly dazzles drivers
of oncoming vehicles and the like.
[0010] FIG. 11 shows a conceptual view of a satisfactory light
distribution. In the figure, a vertical line 2 indicating a center
of the vehicle, and a horizontal line 3 indicating a height of the
headlight of the vehicle (height of the center of optical axis) are
drawn on a wall surface 1 positioned at a predetermined distance
(10 m herein) to the front of the vehicle (not shown). A hatched
portion of the wall surface 1 shows a dark part 4 not illuminated
with the headlight, and a white portion other than the hatched
portion shows a bright part 5 illuminated with the headlight. A
boundary line shown with a heavy light between the dark part 4 and
the bright part 5 is a cutoff line 6. The cutoff line 6 spreads
slightly to the upper side at the portion on a left side of the
vertical line 2 indicating the center of the vehicle, but this is a
devise on light distribution so that pedestrians on the left side
can be easily found and corresponds to a traveling zone (left-hand
traffic) of Japan. Therefore, this devise will obviously be
reversed in foreign countries of right-hand traffic.
[0011] An aspect to be noted in the figure is that the cutoff line
6 is positioned slightly on the lower side of the horizontal line 3
indicating the height of the headlight excluding a pedestrian
portion. Suppose a difference A in the height direction between the
horizontal line 3 and the cutoff line is 4.4 cm for convenience,
since the wall surface 1 is positioned at 10 m in front of the
vehicle, it is 4.4 cm.times.50 m/10 m=22 cm at the position of 50 m
in front of the vehicle, and thus the cutoff line lowers by 22 cm
at the 50 m spot. The relevant lowering amount (22 cm) is a
sufficient value to prevent dazzling on oncoming vehicles, and also
illuminates obstructions at the 50 m spot without trouble.
[0012] If a number of passengers or an amount of load of the
vehicle are changed even if the cutoff line is appropriately set as
above, the cutoff line moves to the upper side, which may dazzle
the drivers of oncoming vehicles and the like. This tendency is
significant in vehicles such as a minivan, where a great number of
seats are provided, and a change in the number of passengers or a
change in the load are large.
[0013] An auto levelizer (hereinafter referred to as a headlight
optical axis adjustment device) for automatically adjusting the
optical axis of the headlight to obtain the correct light
distribution is thus used. The headlight optical axis adjustment
device tilts and adjusts the optical axis of the headlight in a
direction of canceling a pitch angle based on the tilt (hereinafter
also referred to as a pitch angle) in the front and back direction
of the vehicle. In a vehicle mounted with such device, the optical
axis of the head light is automatically adjusted to return to the
correct light distribution when the number of passengers or the
amount of load of the vehicle are changed, and thus the irradiating
light beam is prevented from inhibiting other traffics while
checking the traffic obstructions at the front of the vehicle at
night.
[0014] However, the pitch angle of the vehicle finely fluctuates
not only when the number of passengers or the amount of load are
changed, but also when the passengers goes in/out or when the
baggage is being loaded/unloaded to and from the vehicle, and also
fluctuates when accelerating or decelerating during traveling or
riding over bumps of the road surface. Thus, an optical axis
adjustment mechanism of the headlight operates every time the pitch
angle changes if the device simply "tilts and adjusts the optical
axis of the headlight in a direction of canceling the pitch angle
of the vehicle", and thus operation frequency of actuators such as
a motor arranged in the mechanism increases thereby inhibiting
durability.
[0015] Japanese Unexamined Patent Publication No. 2000-103280
(Japanese Patent No. 3849960) is known as a conventional art for
solving such problem. This publication will be hereinafter referred
to as a first conventional art, where in the first conventional
art, a tilt adjustment of the optical axis of the headlight based
on the pitch angle of the vehicle is performed once while the
vehicle is stopped, and thereafter, the tilt adjustment is
performed for every predetermined interval while the vehicle is
stopped. The tilt adjustment of the optical axis of the headlight
is thus performed limited to only while the vehicle is stopped, and
the number of operations of the actuator such as the motor is
reduced and the durability is enhanced.
[0016] Japanese Unexamined Patent Publication No. 2000-85458
(Japanese Patent No. 3847972) is also known as another conventional
art for solving the above problem. This publication will be
hereinafter referred to as a second conventional art, where in the
second conventional art, the tilt adjustment of the optical axis of
the headlight based on the pitch angle of the vehicle is performed
while the vehicle is stopped, and the title adjustment of the
optical axis of the headlight is performed based on the pitch angle
of when stably traveling instead of the pitch angle of when the
vehicle is stopped if the difference between the pitch angle of
when stably traveling and the pitch angle of when stopped exceeds a
predetermined value while the vehicle is stably traveling (constant
speed travel that does not involve acceleration and deceleration of
greater than or equal to 30 Km per hour). In this case as well, the
tilt adjustment of the optical axis particularly in traveling is
limited to being performed only "if the difference between the
pitch angle of when stably traveling and the pitch angle of when
stopped exceeds a predetermined value", and thus the number of
operations of the actuator such as the motor is reduced and the
durability is enhanced.
SUMMARY
[0017] In a first and second conventional arts, however,
unnecessary operations of an actuator still exist, and a further
improvement is desired in terms of further enhancing
durability.
[0018] In other words, in the first conventional art, a tilt
adjustment of an optical axis of a headlight based on a pitch angle
of a vehicle is performed once while the vehicle is stopped and the
tilt adjustment is performed for every predetermined interval while
the vehicle remains stopped, but at least one tilt adjustment and
the tilt adjustment of every interval are performed even in a
stable state where the passenger does not go in/out and the baggage
is not being loaded/unloaded, and thus the adjustments are waste,
and improvement is desired in terms of further enhancing the
durability.
[0019] In the second conventional art, the tilt adjustment of the
optical axis is performed both while the vehicle is stopped and
while it is traveling at a steady rate, but as there is no
limitation (one adjustment and adjustment of every interval) as in
the first conventional art while the vehicle is stopped, the
actuator such as the motor operates every time the pitch angle
changes, and unnecessary tilt adjustment is frequently performed
even when the passenger goes in/out or when the baggage is being
loaded/unloaded, and thus improvement is desired in terms of
further enhancing the durability.
[0020] The present invention aims to provide a headlight optical
axis adjustment device which avoids unnecessary adjustment by
performing optical adjustment while the vehicle is stopped only in
necessary situations, thereby further enhancing the durability.
[0021] In accordance with a first aspect of the present invention,
the present invention relates to a headlight optical axis
adjustment device for adjusting an optical axis of a headlight
based on a pitch angle of a vehicle; the headlight optical axis
adjustment device including an opened/closed state detection
section for detecting an opened/closed state of an open/close unit
where the opened state is when a passenger gets in/out or when a
baggage is being loaded/unloaded to and from the vehicle; and an
optical axis adjustment permitting section for permitting optical
axis adjustment of the headlight based on the pitch angle of the
vehicle when the opened state of the open/close unit is detected by
the opened/closed state detection section.
[0022] In accordance with a second aspect of the present invention,
the present invention relates to the headlight optical axis
adjustment device according to the first aspect of the present
invention, further including a behavior detection section for
detecting a behavior change of the vehicle necessary for
calculating the pitch angle; wherein the optical axis adjustment
permitting section permits the optical axis adjustment of the
headlight based on the pitch angle of the vehicle when the opened
state of the open/close unit is detected by the opened/closed state
detection section, and a detection value of the behavior detection
section is greater than a predetermined value.
[0023] In accordance with a third aspect of the present invention,
the present invention relates to a headlight optical axis
adjustment device for adjusting an optical axis of a headlight
based on a pitch angle of a vehicle; the headlight optical axis
adjustment device including an opened/closed state detection
section for detecting an opened/closed state of an open/close unit
where the opened state is when a passenger gets in/out or when a
baggage is being loaded/unloaded to and from the vehicle; and an
optical axis setting section for prohibiting the optical axis
adjustment of the headlight based on the pitch angle of the vehicle
when the opened state of the open/close unit is detected by the
opened/closed state detection section, and setting the optical axis
of the headlight to a predetermined angle so as not to dazzle the
drivers of oncoming vehicles and pedestrians.
[0024] In accordance with a fourth aspect of the present invention,
the present invention relates to the headlight optical axis
adjustment device according to the third aspect of the present
invention, further including a behavior detection section for
detecting a behavior change of the vehicle necessary for
calculating the pitch angle; wherein the optical axis setting
section sets the optical axis of the headlight to the predetermined
angle so as not to dazzle the drivers of oncoming vehicles and the
pedestrians when the opened state of the open/close unit is
detected by the opened/closed state detection section, and a
detection value of the behavior detection section is greater than a
predetermined value.
[0025] In accordance with a fifth aspect of the present invention,
the present invention relates to a headlight optical axis
adjustment device for adjusting an optical axis of a headlight
based on a pitch angle of a vehicle; the headlight optical axis
adjustment device including an opened/closed state detection
section for detecting an opened/closed state of an open/close unit
where the opened state is when a passenger gets in/out or when a
baggage is being loaded/unloaded to and from the vehicle; a
behavior detection section for detecting a behavior change of the
vehicle necessary for calculating the pitch angle; a calculation
section for calculating a difference between a scheduled amount of
optical axis adjustment for this time based on the pitch angle and
an optical axis adjustment amount for a previous time when the
closed state of the open/close unit is detected by the
opened/closed state detection section, and a time a detection value
of the behavior detection section is greater than a predetermined
value elapses a predetermined time; and a first optical axis
adjustment execution section for executing the optical axis
adjustment according to the scheduled amount of the optical axis
adjustment for this time if the value of the difference calculated
by the calculation section is greater than a predetermined
value.
[0026] In accordance with a sixth aspect of the present invention,
the present invention relates to the headlight optical axis
adjustment device according to the fifth aspect of the present
invention, wherein the first optical axis adjustment execution
section does not execute further optical axis adjustment when
executed number of times of the optical axis adjustment becomes
greater than a predetermined number of times.
[0027] In accordance with a seventh aspect of the present
invention, the present invention relates to a headlight optical
axis adjustment device for adjusting an optical axis of a headlight
based on a pitch angle of a vehicle; the headlight optical axis
adjustment device including an opened/closed state detection
section for detecting an opened/closed state of an open/close unit
where the opened state is when a passenger gets in/out or when a
baggage is being loaded/unloaded to and from the vehicle; a
behavior detection section for detecting a behavior change of the
vehicle necessary for calculating the pitch angle; and a second
optical axis adjustment execution section for executing an
adjustment of the optical axis based on the pitch angle both when
the opened state of the open/close unit is detected by the
opened/closed state detection section and when the closed state of
the open/close unit is detected by the opened/closed state
detection section; wherein the second optical axis adjustment
execution section executes the adjustment of the optical axis based
on the pitch angle when judging whether or not the detection value
of the behavior detection section is greater than a first
predetermined value (Hopen) for the opened state and judged as
being greater if the opened state of the open/close unit is
detected by the opened/closed state detection section, and executes
the adjustment of the optical axis based on the pitch angle when
judging whether or not the detection value of the behavior
detection section is greater than a second predetermined value for
the closed state and judged as being greater if the closed state of
the open/close unit is detected by the opened/closed state
detection section.
[0028] According to the present invention, the optical axis
adjustment of the headlight based on the pitch angle of the vehicle
is permitted only when the opened/closed state of the open/close
unit such as doors is in the "opened state", where the opened state
is when the passenger goes in/out or when the baggage is being
loaded/unloaded to and from the vehicle, and thus the optical axis
adjustment while the vehicle is stopped is performed only in
necessary situations and unnecessary adjustment can be avoided, and
further enhancement in the durability of the optical axis
adjustment actuator (such as the motor) can be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 shows a block diagram of a headlight optical axis
adjustment device according to an embodiment;
[0030] FIG. 2 shows a view of attachment positions of vehicle
height sensors 20, 21;
[0031] FIG. 3 shows a conceptual view of signal retrieval in a
vehicle height signal retrieving unit 23;
[0032] FIG. 4 shows a view of an operation flow in a first
example;
[0033] FIG. 5 shows a view of the operation flow in a second
example;
[0034] FIG. 6 shows a view of the operation flow in a third
example;
[0035] FIG. 7 shows a view of the operation flow in a fourth
example;
[0036] FIG. 8 shows a view of the operation flow in a fifth
example;
[0037] FIG. 9 shows a block diagram of main elements in a sixth
example;
[0038] FIG. 10 shows a view of the operation flow in a seventh
example; and
[0039] FIG. 11 shows a conceptual view of a satisfactory light
distribution.
DETAILED DESCRIPTION
[0040] Hereinafter, embodiments of the present invention will be
described based on the drawings.
[0041] FIG. 1 shows a block diagram of a headlight optical axis
adjustment device according to an embodiment. In the figure, a
headlight optical axis adjustment device 10 is configured including
a switch and sensor group 11, a leveling controller 12, a right
lamp assembly (hereinafter abbreviated as ASSY) 13R, and a left
lamp ASSY 13L.
[0042] Describing the details of each unit, the switch and sensor
group 11 includes a driver seat door switch (switch is abbreviated
as "SW" in the figure) 14 for detecting opening/closing of a driver
seat door, a passenger seat door switch 15 for detecting the
opening/closing of a passenger seat door, a back seat right door
switch 16 for detecting the opening/closing of a back seat right
door, a back seat left door switch 17 for detecting the
opening/closing of a back seat left door, a hatchback gate switch
18 for detecting the opening/closing of a hatchback gate, and a
front vehicle height sensor 20 and a rear vehicle height sensor 21
for detecting the vehicle height near a front and back axles,
respectively, as a behavior change amount of the vehicle necessary
for calculating a pitch angle .theta.. Here, the hatchback gate is
the door of the rear baggage compartment in a minivan and the like.
In passenger cars and the like, a trunk is provided in place of the
hatchback gate, and thus a trunk switch 19 is arranged in place of
the hatch gate switch 18 when the headlight optical axis adjustment
device 10 in the present embodiment is applied to the passenger car
and the like. Unless particularly stated, the hatchback gate switch
18 and the trunk switch 19 may be similarly handled to detect the
opening/closing of the baggage compartment door. The door, the
gate, and the trunk have different names, but functions are common
in being an open/close unit which is used when the passenger goes
in/out or when the baggage is being loaded/unloaded, and thus the
door, the gate, and the trunk are collectively referred to herein
as a "door" or "door etc.".
[0043] The front vehicle height sensor 20 and the rear vehicle
height sensor 21 are sensors for detecting the vehicle height near
the front and back axles, respectively, and the preferred
attachment positions are as described below.
[0044] FIG. 2 shows a view of attachment positions of the vehicle
height sensors 20, 21. In the figure, the front vehicle height
sensor 20 is attached to a connection point of a suspending device
32 of a front wheel 31 and a vehicle body 33, and the rear vehicle
height sensor 21 is attached to a connection point of a suspending
device 35 of a rear wheel 34 and the vehicle body 33.
[0045] The front and rear suspending devices 32, 35 elastically
suspend the front and rear wheels 31, 34 with respect to the
vehicle body 33, where an entire length of the respective
suspending devices 32, 35 changes when the load of the front and
rear wheels 31, 34 fluctuates or when the front and rear wheels 31,
34 ride over a bump of a road surface, thereby alleviating and
absorbing fluctuation of the load and a ride-over shock of the
bump.
[0046] The pitch angle .theta. of the vehicle is an angle formed by
an actual horizontal line (hereinafter referred to as actual
horizontal line) 37 in the front and back direction of the vehicle
body 33 with respect to a horizontal line (horizontal line passing
through the optical axis of a left and right headlight 30R, 30L in
the figure, hereinafter also referred to as a reference horizontal
line) 36 that becomes a reference in the front and back direction
of the vehicle body 33. The pitch angle .theta. is obtained as a
slope of the actual horizontal line 37 based on a direction and a
magnitude of a change in a detection value Hf of the front vehicle
height sensor 20 and a detection value Hr of the rear vehicle
height sensor 21 on the basis of Hf and Hr when the reference
horizontal line 36 is obtained, where Hf is the detection value of
the front vehicle height sensor 20 and Hr is the detection value of
the rear vehicle height sensor 21.
[0047] For instance, if the vehicle height (Hr) on the rear wheel
side does not change and only the vehicle height (Hf) on the front
wheel side changes in the increasing direction, the pitch angle
.theta. decreases or increases in a positive direction, the slope
of the actual horizontal line 37 changes in the direction of an
arrow A, and the optical axes of the left and right headlights 30R,
30L become horizontal or turned to an upper side. Alternatively, if
the vehicle height (Hf) on the front wheel side does not change and
only the vehicle height (Hr) on the rear wheel side changes in the
decreasing direction, the optical axes of the left and right
headlights 30R, 30L become horizontal or turned to the upper side,
thereby dazzling oncoming vehicles and pedestrians in both
cases.
[0048] The pitch angle .theta. is obtained from the following
equation (1) where L is a spacing (spacing in front and back
direction of the vehicle: wheel base width) between the attachment
position of the front vehicle height sensor 20 and the attachment
position of the rear vehicle height sensor 21.
.theta.=tan.sup.-1((Hf-Hr)/L) (1)
[0049] The leveling controller 12 includes a vehicle door etc.
opening/closing judging unit 22, a vehicle height signal retrieving
unit 23, a timer 24, a pitch angle calculation unit 25, a
correction angle calculation unit 26, and a drive unit 27.
[0050] The vehicle door etc. opening/closing judging unit 22
retrieves signals from each switch 14 to 19 of the switch and
sensor group 11, and judges whether or not one or more doors of the
doors of the vehicle are opened or whether or not all the doors are
closed based on the signals. The vehicle height signal retrieving
unit 23 monitors the vehicle height signals (Hf, Hr) output from
the front vehicle height sensor 20 and the rear vehicle height
sensor 21, and retrieves such signals when the respective signals
indicate a change of greater than or equal to a predetermined
value. The timer 24 times (counts) the predetermined time value.
The pitch angle calculation unit 25 calculates the pitch angle
.theta. based on the vehicle height signals retrieved by the
vehicle height retrieving unit 23, and the correction angle
calculation unit 26 calculates the correction angle in the
direction of canceling out the pitch angle .theta.. The drive unit
27 outputs a drive signal corresponding to the correction angle
calculated in the correction angle calculation unit 26 to the right
lamp ASSY 13R and the left lamp ASSY 13L.
[0051] The right lamp ASSY 13R includes a right lamp irradiating
direction control unit 28R, a right drive mechanism 29R including
an actuator such as a motor, and a right headlight 30R which angle
to an upper side and a lower side of a reflector is changed by the
right drive mechanism 29R, and similarly, the left lamp ASSY 13L
also includes a left lamp irradiating direction control unit 28L, a
left drive mechanism 29L including the actuator such as the motor,
and a left headlight 30L which angle to the upper side and the
lower side of the reflector is changed by the left drive mechanism
29L.
[0052] FIG. 3 shows a conceptual view of signal retrieval in the
vehicle height signal retrieving unit 23. In the figure, a
horizontal axis is time, and a period between time t0 to t7 showing
control timing is a control cycle of a same time length. A line 38
that fluctuates up and down in the figure represents the detection
signal (Hf, Hr) of the front vehicle height sensor 20 or the rear
vehicle height sensor 21, and such line 38 fluctuates little by
little or greatly up and down in some cases. The fluctuation is
caused by various factors. For instance, the fluctuation occurs
when the passenger goes in/out or when the baggage is being
loaded/unloaded while the vehicle is stopped, or occurs by an
influence of wind when exposed to strong wind. The fluctuation may
also occur when accelerating or decelerating, or when riding over a
bump or a pocket of the road surface while traveling.
[0053] The detection signal of the front vehicle height sensor 20
or the rear vehicle height sensor 21 is actually always fluctuating
slightly or greatly at times, but if all such fluctuations of the
detection signal are captured, the pitch angle is frequently
adjusted for every control timing (t0, t1, t2, . . . ), which may
affect the durability of the actuator such as the motor arranged in
the drive mechanism (left and right drive mechanism 29R, 29L) of
the left and right lamp ASSYs 13R, 13L, and thus it is not
preferable. In the present embodiment, retrieval is made only if a
large fluctuation of a certain extent is found in the detection
signal of the front vehicle height sensor 20 or the rear vehicle
height sensor 21 assuming an effective signal fluctuation
exists.
[0054] Specifically, a judgment region (hysteresis region) having a
predetermined upper and lower widths indicated with hatching in the
figure is arranged, and retrieval is made assuming an effective
signal fluctuation exists only if a signal change exceeding the
judgment region is found. Therefore, in the illustrated example, a
portion of the line 38 in the judgment region indicated with
hatching is ignored, and only the portion of heavy line exceeding
the judgment region is retrieved on the assumption that the
effective signal fluctuation exists. In the present embodiment, two
types of judgment region (hysteresis region) are prepared, one to
be applied when the door is opened and one to be applied when the
door is closed as described hereinafter, and are respectively
referred to as "Hopen" (applied when the door is opened) and
"Hclose" (applied when the door is closed).
[0055] Specific control operation of the relevant embodiment will
be described below using examples.
First Example
[0056] FIG. 4 shows a view of an operation flow in a first example.
In this example, the opening/closing of the doors (driver seat
door, passenger seat door, back seat right door, back seat left
door, hatching gate, trunk) is judged by the vehicle door etc.
opening/closing judging unit 22 (step S11), where when judged that
one or more doors is opened ("YES" in step S11), presumption and
judgment are made as being in a situation where the passenger goes
in/out or the baggage is being loaded/unloaded, and the change in
the pitch angle .theta. generated during the door opened state is
calculated from the detection signals (Hf, Hr) of the front vehicle
height sensor 20 and the rear vehicle height sensor 21, and the
control amount of each drive mechanism (right drive mechanism 29R
and left drive mechanism 29L) of the right lamp ASSY 13R and the
left lamp ASSY 13L is determined based on the calculation result,
so that the optical axes of the right headlight 30R and the left
headlight 30L are adjusted in the direction of canceling out the
change in the pitch angle .theta. (step S12, step S13).
[0057] Even if judged that the door is opened, the detection
signals (Hf, Hr) of the front vehicle height sensor 20 and the rear
vehicle height sensor 21 during the time are not retrieved as is,
and are retrieved assuming that an effective signal fluctuation
exists only when a signal change exceeding the judgment region
(hysteresis: Hopen herein) of predetermined upper and lower widths
is present. The reason is as described above, where since the
detection signal of the front vehicle height sensor 20 or the rear
vehicle height sensor 21 is always fluctuating slightly or greatly
at times, if all such fluctuation of the detection signal is
captured, the pitch angle .theta. is frequently adjustment operated
for every control cycle, which may affect the durability of the
actuator such as the motor arranged in the drive mechanism (left
and right drive mechanism 29R, 29L) of the left and right lamp
ASSYs 13R, 13L.
[0058] According to the first example, the optical axis adjustment
based on the pitch angle .theta. is executed only when the door is
opened and when both or one of the detection signals (Hf, Hr) of
the front vehicle height sensor 20 and the rear vehicle height
sensor 21 exceeds the judgment region (hysteresis region: Hopen
herein) of predetermined upper and lower widths, and thus the
optical axis adjustment while the vehicle is stopped is performed
only under necessary situations, and the headlight optical axis
adjustment device 10 achieving further enhancement in durability is
provided.
Second Example
[0059] FIG. 5 shows a view of an operation flow in a second
example. In this example, the opening/closing of the door (driver
seat door, passenger seat door, back seat right door, back seat
left door, hatchback gate, trunk) is judged by the vehicle door
etc. opening/closing judging unit 22 (step S21), where when judged
that one or more doors are opened ("YES" in step S21), presumption
and judgment are made as being in a situation where the passenger
goes in/out or the baggage is being loaded/unloaded, and the
optical axes of the right headlight 30R and the left headlight 30L
are adjusted to "lower side" (preferably lowermost side) (step
S22).
[0060] Herein, adjusting the optical axis to "lower side" means the
following. Each drive mechanism (right drive mechanism 29R and left
drive mechanism 29L) of the right lamp ASSY 13R and the left lamp
ASSY 13L moves the optical axis (accurately, tilt angle of
reflector) of the right headlight 30R and the left headlight 30L,
but the movement amount has a certain limit, and referring the
lower limit tilt angle (e.g., -10 degrees) as the lower most side
for the sake of convenience, adjusting the optical axis to "lower
side" refers to setting the optical axis to one of the angles
between horizontal to the lowermost side, and preferably to the
lowermost side (lower limit tilt angle). Thus, dazzling on the
oncoming vehicles, the pedestrians and the like can be prevented by
setting the optical axis to the lower side and the dazzling can be
reliably prevented by setting the optical axis at the lowermost
side.
[0061] According to the second example, the dazzling on the
oncoming vehicles and pedestrians can be prevented while avoiding
involuntary change (horizontal or upper side change etc.) of the
optical axis when the passenger goes in/out or when the baggage is
being loaded/unloaded since the optical axis of the headlight is on
the lower side (lowermost side in a best preferred mode) when the
door is opened. In the first example, after executing the
adjustment of the optical axis to the lower side (step S22), a
re-execution of the adjustment of the optical axis to the lower
side (step S22) is desirably prohibited while being judged that the
door is opened. It is useless to again perform the lower side
adjustment after adjusting the optical axis to the lower side once
as it affects the durability.
Third Example
[0062] FIG. 6 shows a view of an operation flow in a third example.
In this example, the opening/closing of the doors (driver seat
door, passenger seat door, back seat right door, back seat left
door, hatching gate, trunk) is judged by the vehicle door etc.
opening/closing judging unit 22 (step S31), where when judged that
one or more doors are opened ("YES" in step S31), presumption and
judgment are made as being in a situation where the passenger goes
in/out or the baggage is being loaded/unloaded, and only the lower
side control of the optical axis of the headlight is permitted
(step S33) only when both or one of the detection signals (Hf, Hr)
of the front vehicle height sensor 20 and the rear vehicle height
sensor 21 exceeds the judgment region (hysteresis region: Hopen
herein) of predetermined upper and lower widths (step S32), and the
optical axes of the right headlight 30R and the left headlight 30L
are adjusted (step S34).
[0063] In step S33, the reason for "permitting only the lower side
control of the optical axis of the headlight" is because the
possibility of dazzling the oncoming vehicles and pedestrians
increases if the control direction of the optical axis obtained by
the change in the detection signal is "upper side" even if both or
one of the detection signals (Hf, Hr) of the front vehicle height
sensor 20 and the rear vehicle height sensor 21 exceeds the
judgment region (hysteresis region: Hopen herein) of predetermined
upper and lower widths, where such drawback can be resolved by
performing the optical axis control limited only to the lower
side.
[0064] Therefore, according to the third example, since only the
lower side control of the optical axis of the headlight is
permitted when the door is opened and when both or one of the
detection signals (Hf, Hr) of the front vehicle height sensor 20
and the rear vehicle height sensor 21 exceeds the judgment region
(hysteresis region: Hopen herein) of predetermined upper and lower
widths, the optical axis adjustment while the vehicle is stopped is
performed only under necessary situations, whereby the durability
further enhances, and the dazzling on the oncoming vehicles and
pedestrians can be reliably prevented.
Fourth Example
[0065] FIG. 7 shows a view of an operation flow in a fourth
example. In the examples above (first example to third example),
the optical axis adjustment is performed when the door is in the
"opened" state, but the fourth example differs in that the optical
axis adjustment is performed when the door is in the "closed"
state.
[0066] In other words, in this example, the opening/closing of the
doors (driver seat door, passenger seat door, back seat right door,
back seat left door, hatching gate, trunk) is judged by the vehicle
door etc. opening/closing judging unit 22 (step S41), where when
judged that all the doors are closed ("YES" in step S41), judgment
is made on whether or not both or one of the detection signals (Hf,
Hr) of the front vehicle height sensor 20 and the rear vehicle
height sensor 21 exceeds the judgment region (hysteresis region:
Hclose herein) of predetermined upper and lower widths (step S42).
If the judgment region is exceeded, the timer 24 is set (step S43),
and if not exceeded, determination on whether the counter 24 is
counting is made (step S44). The timer 24 is a counting device for
periodically counting the values, and the setting of the timer 24
refers to starting the counting operation.
[0067] If the timer 24 is elapsed (count value reaches a
predetermined value), the difference with the previously calculated
pitch angle is obtained, and whether or not such difference is
greater than or equal to a predetermined value is determined (step
S45), and the optical axis adjustment based on the pitch angle
.theta. is executed when greater than or equal to the predetermined
value (step S46).
[0068] According to the fourth example, when the door is in the
closed state, if the difference between the pitch angle for this
time calculated by the detection signal exceeding the Hclose of the
front vehicle height sensor 20 and the rear vehicle height sensor
21 and the pitch angle used in the optical axis adjustment of the
previous time is changed by greater than or equal to a
predetermined value and if such change continued for a
predetermined time (counting time of timer 24), determination is
made that the change of the pitch angle is in a stable state and
the optical axis of the headlight is adjusted, and thus the optical
axis adjustment of the headlight is not performed on the
instantaneous or temporary pitch angle change, whereby the
durability of the actuator can be enhanced. For instance, when the
pitch angle continuously changes for a certain time such as when
one wheel runs on a curb while being stopped, the optical axis
adjustment of the headlight is performed thereby preventing the
dazzling on the oncoming vehicles and pedestrians.
Fifth Example
[0069] FIG. 8 shows a view of an operation flow in a fifth example.
In the fifth example as well, the optical axis adjustment is
performed when the door is in the "closed" state similar to the
fourth example.
[0070] In other words, in this example, the opening/closing of the
doors (driver seat door, passenger seat door, back seat right door,
back seat left door, hatching gate, trunk) is judged by the vehicle
door etc. opening/closing judging unit 22 (step S51), where a
later-described "changed number of times" (number of executions of
the optical axis adjustment based on the pitch angle .theta. while
the door is closed) is cleared (step S59) when judged that one or
more doors are opened ("opened" in step S51), and whether or not
the later-described "changed number of times" is smaller than the
defined number of times is determined (step S52) when judged that
all the doors are closed ("closed" in step S51). If smaller than
the defined number of times, whether or not both or one of the
detection signals (Hf, Hr) of the front vehicle height sensor 20
and the rear vehicle height sensor 21 exceeds the judgment region
(hysteresis region: Hclose herein) of predetermined upper and lower
widths is determined (step S53). If the judgment region is
exceeded, the timer 24 is set (step S54), and if not exceeded,
determination on whether the counter 24 is counting is made (step
S55). The timer 24 is a counting device for periodically counting
the values, and the setting of the timer 24 refers to starting the
counting operation.
[0071] If the timer 24 is elapsed (count value reaches a
predetermined value), the difference with the previously calculated
pitch angle is obtained, whether or not such difference is greater
than or equal to a predetermined value is determined (step S56),
and the optical axis adjustment based on the pitch angle .theta. is
executed when greater than or equal to the predetermined value
(step S57), and thereafter the "changed number of times" is counted
(step S58). The "changed number of times" is cleared (initialized)
when the door is opened (step S59).
[0072] According to the fifth example, the number of executions of
the optical axis adjustment based on the pitch angle .theta. while
the door is closed is counted as the "changed number of times", and
the optical axis adjustment of the headlight is performed only when
the "changed number of times" is smaller than the defined value.
Specifically, if the difference between the pitch angle for this
time calculated by the detection signal exceeding Hclose of the
front vehicle height sensor 20 and the rear vehicle height sensor
21 and the pitch angle used in the optical axis adjustment of the
previous time is changed by greater than or equal to a
predetermined value, and if such change continued for a
predetermined time (counted time of timer 24), determination is
made that the change in pitch angle is in a stable state and the
optical axis of the headlight is adjusted.
[0073] Therefore, similar to the fourth example, the durability of
the actuator can be further enhanced so as not to perform the
optical axis adjustment of the headlight on instantaneous or
temporary pitch angle change, and for example, when the pitch angle
continuously changes for a certain time such as when one wheel runs
on the curb while being stopped, the optical axis adjustment of the
headlight is performed thereby preventing dazzling on the oncoming
vehicles and pedestrians, and in addition, the optical adjustment
is prevented from being further performed when the number of
executions ("changed number of times") of the optical axis
adjustment becomes greater than the defined value, and the
durability of the actuator can be further enhanced.
Sixth Example
[0074] FIG. 9 shows a configuration of main elements in the sixth
example. In the figure, a switch group 39 includes each door switch
of FIG. 1 (driver seat door switch 14, passenger seat door switch
15, back seat right door switch 16, back seat left door switch 17,
hatchback gate switch 18, trunk switch 19) (in the figure, the
driver seat door switch 14 and trunk switch 19 are representatively
shown in the figure). All the switches 14 to 19 are connected in
parallel between a ground and an output of a drive unit 27 of the
leveling controller 12, and when at least one of the switches 14 to
19 is turned ON (i.e., when one or more doors are opened), the
output of the leveling controller 27, that is, a correction value
for the optical axis adjustment applied on the left and right lamps
ASSY 13R, 13L drops to a ground potential (0V). The left and right
lamps ASSY 13R, 13L set the optical axis of the headlight to a
predetermined tilt angle corresponding to 0V when "0V" is given as
the correction value for optical axis adjustment.
[0075] According to the sixth example, "when detected that the door
is opened, the optical axis adjustment is prohibited until detected
that the door is closed the next time", and specifically, the
optical axis adjustment is not performed while the door is detected
as opened even if the pitch angle is changed with the going in/out
of the passenger and the loading/unloading of the baggage
(precisely, fixing the optical axis of the headlight to a
predetermined tilt angle), and the optical axis adjustment is
permitted when the door is closed, so that the durability can be
enhanced by avoiding unnecessary operation of the actuator, and the
desired optical axis adjustment can be performed at the point the
door is closed, thereby preventing dazzling on the oncoming
vehicles and pedestrians by inappropriate optical axis. Here, the
ground potential (0V) is given to the left and right lamps ASSY
13R, 13L when the door is open, but is not limited thereto. The
potential merely needs to be that which can set the optical axis to
the tilt angle that does not dazzle the drivers of oncoming
vehicles and pedestrians, and may be potentials other than 0V as
long as such condition is satisfied.
Seventh Example
[0076] FIG. 10 shows a view of an operation flow in a seventh
example. In this example, the opening/closing of the doors (driver
seat door, passenger seat door, back seat right door, back seat
left door, hatching gate, trunk) is judged by the vehicle door etc.
opening/closing judging unit 22 (step S61), where when judged that
one or more doors are opened ("YES" in step S61), whether or not
both or one of the detection signals (Hf, Hr) of the front vehicle
height sensor 20 and the rear vehicle height sensor 21 exceeds the
judgment region (door open hysteresis region: Hopen herein) of
predetermined upper and lower widths is judged (step S62), where
when not judged that one or more doors are opened ("NO" in step
S61), whether or not both or one of the detection signals (Hf, Hr)
of the front vehicle height sensor 20 and the rear vehicle height
sensor 21 exceeds the judgment region (door close hysteresis
region: Hclose herein) of predetermined upper and lower widths is
determined (step S64).
[0077] In a case where the door is opened or the door is closed, if
both or one of the detection signals (Hf, Hr) of the front vehicle
height sensor 20 and the rear vehicle height sensor 21 exceeds the
judgment region (door open.fwdarw.Hopen, door close.fwdarw.Hclose)
of predetermined upper and lower widths, the optical axis
adjustment based on the pitch angle .theta. is executed to adjust
the optical axes of the right headlight 30R and the left headlight
30L (step S53).
[0078] According to the seventh example, by providing the judgment
region (hysteresis region) individually for when the door is opened
and for when the door is closed, an "allowance" of having a door
close judgment region larger than a door open judgment region
becomes possible to reduce the number of operations when the door
is closed, the number of respective optical axis adjustment for
door open and door close becomes suitable thereby enhancing the
durability of the actuator and the like.
[0079] In the above description, the vehicle height sensor (front
vehicle height sensor 20 and rear vehicle height sensor 21) is
arranged near the front and back axle to obtain a behavior change
amount (vehicle height) of the vehicle necessary for calculating
the pitch angle .theta., but is not limited thereto, and the
vehicle height sensor may be arranged on only one of near the front
or the back axle. That is, one of either the front vehicle height
sensor 20 or the rear vehicle height sensor 21 may be arranged. The
pitch angle .theta. can be obtained by calculation based on the
vehicle height (one of Hf or Hr) detected with one vehicle height
sensor. For instance, Japanese Patent No. 3850943 discloses a
method of obtaining the pitch angle using a measurement value of
the one vehicle height sensor and a load distribution of the
vehicle, and such method may be used.
[0080] If the vehicle is stopped at a location with a gradient such
as a hill, the pitch angle .theta. of the vehicle changes with such
gradient, but in the present embodiment, the optical axis
adjustment of the headlight is not performed on the change in the
pitch angle .theta. generated by such gradient. The reason is
because the optical axis adjustment is performed limited only when
the detection value of the vehicle height sensor exceeds a constant
range (range of hysteresis region) (during the control cycle), and
in addition, when the optical axis adjustment is performed, the
correction value is calculated by a "displacement amount" of the
detection value of the front vehicle height sensor 20, a
"displacement amount" of the detection value of the rear vehicle
height sensor 21, and a wheel base width (see reference numeral L
of FIG. 2). Therefore, only "displacement amount compared to the
start of measurement for this time" of the vehicle height
measurement value becomes important, and the adjustment of the
optical axis is not influenced by the gradient of the road.
* * * * *