a) and 4(b) illustrate explanatory views of a light receiving face for an overhead sign arranged on a front side of the movable shade of the lamp unit shown in
a) is a sectional view taken along a line A-A of
a) is an explanatory view for moving a light distribution pattern to the left by swiveling the lamp unit shown in
a) and 8(b) illustrate explanatory views of a light receiving face for an overhead sign according to other embodiment of the invention,
Exemplary embodiments of the invention will be described with reference to the accompanying drawings.
According to a vehicle headlamp 10 of the first exemplary embodiment, as shown by
As shown by
The aiming mechanism is a mechanism for finely adjusting an attaching position and an attaching angle of the lamp unit 18. At a stage of adjusting aiming, a lens center axis Ax of the lamp unit 18 is extended in a direction downward by about 0.5 through 0.6 degree relative to a front and rear direction of a vehicle.
The frame 22 is constituted by a shape of substantially a rectangular frame in view from a front side and is provided with support plates 24, 26 extended in the front and rear direction on upper and lower sides. A front end portion of the support plate 24 on the upper side is provided with a bearing portion 24a A supported shaft 31a provided at an upper portion of the lamp unit 18 is rotatably supported by the bearing portion 24a. The support plate 26 on the lower side is formed with a shaft inserting hole 26a in a circular shape at a portion of a rear end portion of the support plate 26 disposed right below the bearing portion 24a. Further, a lower face of the support plate 26 on the lower side of the frame 22 is fixed with a swivel actuator 66 for pivoting the lamp unit 18 in a horizontal direction.
According to the swivel actuator 66 constituting a swivel mechanism, for example, an output shaft 66a is rotated by being driven in accordance with a steering operation. The output shaft 66a is inserted into the shaft inserting hole 26a of the support plate 26, fitted to a connecting shaft 31b provided at a lower portion of the lamp unit 18, and the connecting shaft 31b is connected to the output shaft 66a.
Therefore, when the swivel actuator 66 is driven, the output shaft 66a is rotated, and the lamp unit 18 is pivoted in the horizontal direction in accordance with rotation of the output shaft 66a.
As shown by
The shade mechanism 29 enables to selectively switch distributed light for irradiating a low beam (passing beam) or for a high beam in accordance with a situation of running the vehicle or the like. The shade mechanism 29 is constituted by a movable shade 30 arranged between the projector lens 11 and the light source 23a such that an upper end edge 30ais disposed at a vicinity of the lens center axis Ax at a vicinity of the rear side focal point F of the projector lens 11 for forming a cutoff line of a light distribution pattern by blocking a portion of reflected light from the reflector 25 and a portion of direct light of the light source 23a, a fixed shade 32 arranged at an inner space of the holder 31, a rod member 40 and an actuator 20 for making the movable shade 30 carry out a pivoting operation.
The projector lens 11 comprises a flat convex lens having a front side surface in a convex face and a rear side surface in a flat face for projecting an image in a shape of a focal face including the rear side focal point F to a front side as an inverted image.
The light source bulb 23 is a discharge bulb of a metal halide bulb or the like constituting a discharge light emitting portion by the light source 23a, and is inserted to be fixed to a rear end portion of the reflector 25 constituting a bulb axis by a direction coinciding with the lens center axis Ax in the case of the embodiment.
The light source bulb 23 is attached with a bulb socket 60. Further, a power feed cord 61 led out from the bulb socket 60 is extended to a lower side by passing a back side of the lamp unit 18, and connected to a lighting circuit unit 65 arranged at a lower portion of the lamp body 12, thereby, a lighting voltage and a starting voltage are supplied from a discharge lighting circuit provided to the lighting circuit unit 65 to the light source bulb 23.
Further, a halogen bulb or the like can also be used in place of the discharge bulb, or the light source bulb 23 can be inserted to fix from a side direction of the reflector 25 in a direction of substantially intersecting the bulb shaft to the lens center axis Ax.
Here, although the conception of the ‘direction substantially intersecting with the lens center axis Ax’ naturally includes a case of arranging the optical axis of the light source bulb 23 orthogonally to the lens center axis Ax extended in the front and rear direction of the vehicle, the conception also includes a case of arranging the optical axis to be three-dimensionally intersecting with the lens center axis Ax, a case of arranging the optical axis in a state of being inclined to a horizontal line in a width direction of the vehicle by about ±15°.
The reflector 25 includes a reflecting face 25a in a shape of an ellipsoid constituting a center axis thereof by the lens center axis Ax passing the light source 23a.
The reflecting face 25a is set to substantially ellipsoidal sectional shape including the lens center axis Ax of which constitutes a first focal point by a position of a center of the light source 23a and constitutes a second focal point by a vicinity of the rear side focal point F of the projector lens 11 for condensing and reflecting light from the light source 23a to a front side to be proximate to the lens center axis Ax. Further, an eccentricity of the reflecting face 25a is set to be gradually increased from a vertical section to a horizontal section.
The reflecting plate 25b for the overhead sign is integrally formed with the reflector 25 as a reflecting face continuous to an end portion of the reflecting face 25a of the reflector 25.
Hence, a formed part can be simplified by forming the reflecting plate 25b for the overhead sign integrally with the reflector 25.
The reflecting plate 25b for the overhead sign is set to substantially an ellipsoid a sectional shape including the lens center axis Ax of which constitutes a first focal point by the position of the center of the light source 23a and constitutes a second focal point by a vicinity of a center of the light receiving face 28a for the overhead sign disposed slightly frontward from the rear side focal point F of the projector lens 11 for condensing and reflecting light from the light source 23a to the light receiving face 28a for the overhead sign. Further, an eccentricity of the reflecting plate 25b for the overhead sign is set to gradually increase from a vertical section to a horizontal section.
The light receiving face 28a for the overhead sign is a reflecting face formed integrally with a front face of the movable shade 30. The light receiving face 28a for the overhead sign is formed by substantially a parabolaid of revolution constituting a center axis by a line segment extended from the second focal point of the reflecting plate 25b for the overhead sign in a front upward direction and constituting a focal point thereof by the second focal point of the reflecting plate 25b for the overhead sign, and light incident on the light receiving face 28a for the overhead sign from the reflecting plate 25b for the overhead sign is incident on the projector lens 11 as parallel light irradiated in an upper direction.
The holder 31 includes a rear end portion in a shape of a semicircular arc fixedly supported by a front end opening portion of the reflector 25, a front end portion in a shape of a circular ring for fixedly supporting the projector lens 11, and a plurality of connecting ribs connecting these.
The fixed shade 32 is a shade for preventing stray light reflected by the reflector 25 incident on the projector lens 11 and is formed integrally with the holder 31.
The movable shade 30 is a die cast product and is provided to be disposed at a lower vicinity of the lens center axis Ax in the inner space of the holder 31, and is supported pivotably around a rotating shaft 42 extended in a vehicle width direction. The rotating shaft 42 is rotatably supported by a support portion 43 integrally formed with a back face of the fixed shade 32, although not illustrated.
An end portion of the movable shade 30 is fixedly mounted with a cam plate 44 integrally rotated with the movable shade 30 around the rotating shaft 42. The cam plate 44 is connected with one end of the rod member 40. Other end of the rod member 40 is connected to a plunger 20b constituting an output shaft of the actuator 20.
The actuator 20 is a solenoid for driving to extract and retract the plunger 20b contained in a main body 20athereof in a direction in parallel with the lens center axis Ax relative to the main body 20afixed to the support plate 26, and is operated when a beam switching switch, not illustrated, is operated for switching a position of the movable shade 30 by pivoting the cam plate 44 around the rotating shaft 42 by moving the rod member 40 in accordance with extracting and retracting operation of the plunger 20b.
When the beam switching switch is set to a position of selecting a low beam, the plunger 20b of the actuator 20 is brought into a state of being maximally projected from the main body 20aas shown by
Further, the rotating shaft 42 is mounted with a return spring (not illustrated) by a torsional coil spring for urging the movable shade 30 to a side of the blocking position.
On the other hand, when the beam switching switch is set to a position of selecting a high beam, as shown by an arrow mark B in
Further, when the beam switching switch is switched from the position of selecting a high beam to a position of selecting a low beam, by an urge force of the return spring mounted to the rotating shaft 42, the cam plate is pivoted in the original direction, the plunger 20b of the actuator 20 is returned to an original projected amount, and the movable shade 30 returns to the blocking position.
As shown by
Further, as described above, a front face of the movable shade 30 is formed with the light receiving face for the overhead sign, as shown by
Further, according to the embodiment, an additional illuminance reducer 52 for reducing a portion of irradiating light by the light receiving face 28a for the overhead sign is provided on the light receiving face 28a for the overhead sign on the lower side of the illuminance reducer 51.
In the case of the embodiment, the illuminance reducer 51 and the additional illuminance reducer 52 are constituted by notch portions constituted by cutting the surface of the light receiving face 28a for the overhead sign in a shape of a cylindrical face, light reflected by the notch portion is not incident on the projector lens 11.
Next, a light distribution by the vehicle headlamp 10 will be explained.
As shown by
Reflected light P1 from the reflecting plate 25b for the overhead sign is incident on the projector lens 11 as light in an upper direction by the light receiving face 28a for the overhead sign, emitted as overhead sign irradiating light P2 from the projector lens 11, and forms an OHS light distribution pattern PX for irradiating the overhead sign on an upper side of the light distribution pattern PL for a low beam.
The OHS light distribution pattern PX forms an irradiating region in a shape of an ellipse a long axis of which is extended in the vehicle width direction, and inside of the distributed light is formed with dark portions 54, 55 in a spot-like shape the illuminance of which are reduced more than that of surrounding by the illuminance reducer 51 and the additional illuminance reducer 52.
According to the dark portion 54, there is formed a dark portion having an illuminance lower than that of a surrounding thereof at a portion in the light distribution pattern PX in conformity with a countermeasure against glare of a vehicle running on an opposed lane or laws or regulations or the like.
According to the vehicle headlamp 10 of the embodiment explained above, the light flux reflected by the light receiving face 28a for the overhead sign and incident on the projector lens 11 as light in the upper direction becomes overhead sign irradiating light P2 for irradiating the overhead sign.
Further, at a region of providing the illuminance reducer 51 on the light receiving face 28a for the overhead sign, an emitted light amount is reduced more than that of the region of the surrounding. As a result, the illuminance is reduced at the position in correspondence with the illuminance reducer 51 on the light distribution pattern PX by the overhead sign irradiating light P2, and the dark portion 54 having the illuminance lower than that of the surrounding is formed.
Further, the position of the dark portion 54 having the illuminance lower than that of the surrounding in the light distribution pattern PX by the overhead sign irradiating light P2 can simply be adjusted to an arbitrary position by adjusting a position of mounting the illuminance reducer 51.
Hence, there can simply and firmly be provided ideal overhead sign irradiating light P2 for forming the dark portion having an illuminance lower than that of the surrounding at a portion of the light distribution pattern PX in conformity with a countermeasure against glare of a vehicle running on an opposed lane or laws or regulations or the like.
Further, as a method of partially reducing the light amount reflected by the light receiving face 28a for the overhead sign, it is conceivable to provide a raised portion for hampering light from being reflected to the side of the projector lens 11 at a corresponding portion of the light receiving face 28a for the overhead sign, in a case of a constitution of providing the raised portion as the illuminance reducer 51, there is a possibility of reducing a rate of utilizing the light flux by blocking a portion of original distributed light passing the upper end edge of the movable shade 30 for illuminating a road face by the raised portion.
Hence, when the illuminance reducer 51 is constituted by the notch portion as in the embodiment, for example, a portion of original distributed light passing the upper end edge 30a of the movable shade 30 for illuminating a road face is not blocked and the rate of utilizing the light flux can be prevented from being reduced.
Further, when the illuminance reducer 51 is formed by the notch portion as in the embodiment, light-weighted formation of the movable shade 30 constituting a member of providing the light receiving face 28a for the overhead sign can be achieved by an amount of cutting the notch portion.
Hence, by light-weighted formation of the movable shade 30 for switching irradiation of a road face to a low beam or to a high beam, the movable operation of the movable shade 30 can be facilitated by alleviating a load on the actuator 20 for making the movable shade 30 movable.
Next, an explanation will be given of distributed light when a failsafe operation of moving down the optical axis is carried out after horizontally rotating the lamp unit 18 by the swivel actuator 66 by a predetermined angle.
According to the vehicle headlamp 10 of the embodiment, when the failsafe operation is carried out by a failure or the like of the swivel mechanism, the optical axis of the lamp unit 18 is moved down after horizontal rotation by the swivel actuator 66.
Hence, irradiating regions by the respective light distribution patterns PL, PX are horizontally moved in a left direction indicated by a narrow mark D in
That is, by horizontally moving the respective light distribution patterns PL, PX in the left direction by the fail safe operation, the dark portion 55 formed by the additional illuminance reducer 52 is moved right above a position (assumed position K54) of the dark portion 54 formed by the illuminance reducer 51 before the swivel operation. Further, by moving the respective light distribution patterns PL, PX to the lower side in parallel with each other, the dark portion 55 overlaps the position (assumed position K54) of the dark portion 54 formed by the illuminance reducer 51 before the swivel operation.
Therefore, when the lamp unit 18 carries out the failsafe operation, the dark portion 55 formed by the additional illuminance reducer 52 is moved to the dark portion 54 formed by the illuminance reducer 51 to maintain a function for a countermeasure against glare of a vehicle running on an opposed lane. Therefore, compliance of laws and regulations for regulating glare from being brought about can be promoted without losing the countermeasure against glare of the vehicle running on the opposed lane in the failsafe operation.
Further, specific structures of the illuminance reducer 51 and the additional illuminance reducer 52 mounted to the light receiving face 28a for the overhead sign according to the invention are not limited to the notch portion in the shape of the cylindrical face according to the first embodiment.
For example, as shown by
The low reflecting portion 57 is a portion of roughening the reflecting face by, for example, drawing or the like, when such a constitution is constructed, the illuminance reducer 51 and the additional illuminance reducer 52 can further simply be formed.
Further, according to the embodiment, the reflecting face 25b for the overhead sign of the additional reflector is constituted by the reflecting face continuous to the end of the reflecting face 25a of the reflector 25. However, a constitution shown by
According to the lamp unit 58 of the second exemplary embodiment, the reflecting face 127a for the overhead sign is a reflecting face formed at an inner face of the reflector 127 formed separately from the reflector 125.
Further, according to the first and the second exemplary embodiments, the shade mechanism 29 is provided with the movable shade 30, and the front face per se of the movable shade 30 is formed into the light receiving face 28a for the overhead sign.
However, a mode of mounting the light receiving face for the overhead sign according to the invention is not limited to the structure shown in the above-described exemplary embodiments.
A lamp unit 68 shown in the third exemplary embodiment is contained in a lamp chamber formed by a lamp body and a transparent cover similar to the lamp unit 18 shown in the first exemplary embodiment although not illustrated.
As shown by
Further, a position of a vicinity of an upper end of the first fixed shade 72 of the light receiving face 74 for the overhead sign is provided with illuminance reducer 75 for reducing a portion of irradiating light by the light receiving face 74 for the overhead sign.
According to the third exemplary embodiment, the reflector 225 includes the reflecting face 225a substantially in a shape of an ellipsoid constituting a center axis by the lens center axis Ax passing the light source 123a.
According to the reflecting face 225a, a sectional shape including the lens center axis Ax is set to substantially an ellipsoid constituting a first focal point by a center position of the light source 123a and constituting a second focal point by a vicinity of the rear side focal point F of the projector lens 11 for condensing and reflecting light from the light source 123a to the front side to be proximate to the lens center axis Ax.
The shade mechanism 69 is constituted by the first fixed shade 72 arranged between the projector lens 11 and the light source 123a such that an upper end edge 72a is disposed at a vicinity of the lens center axis Ax at a vicinity of the rear side focal point F of the projector lens 11 for forming a cutoff line of a light distribution pattern by blocking a portion of reflected light from the reflector 225 and a portion of direct light from the light source 123a, and a second fixed shade 232 arranged at an inner space of a holder 231 in a cylindrical shape connecting the reflector 225 and the projector lens 11.
The second fixed shade 232 is a shade for preventing stray light reflected by the reflector 225 from being incident on the projector lens 11 and is formed integrally with the holder 231.
In the case of the third exemplary embodiment, the reflecting face 225b for the overhead sign is formed integrally with the reflector 225 to be smoothly continuous to a front end portion of the reflecting face 225a of the reflector 225.
The light receiving face 74 for the overhead sign is provided by reflecting means 76 made by a metal plate fixed to a side of a front face of the first fixed shade 72.
As shown by
A characteristic of the third exemplary embodiment resides in a point that a portion of the inclined face portion 76b for providing the light receiving face 74 for the overhead sign is formed with an opening portion 77 by cutting to raise the portion, and the opening portion 77 is utilized as the illuminance reducer 75. Further, the characteristic resides in a point that a front end 78a of a cut-to-raise piece 78 constituted by being cut to raise when the opening portion 77 is formed is disposed at a vicinity of the upper end edge 72a of the first fixed shade 72.
According to the constitution, light P1 incident on the opening portion 77 formed by being cut to raise is not reflected to the side of the projector lens 11. Therefore, at a position in correspondence with the opening portion 77 on the light distribution pattern by reflected light at the light receiving face 74 for the overhead sign, a light amount is reduced, a dark portion having an illuminance lower than that of the surrounding is constituted, and there can be provided ideal overhead sign irradiating light for forming a dark portion having an illuminance lower than that of the surrounding at a portion in the light distribution pattern in conformity with a countermeasure against glare of a vehicle running on an opposed lane or laws or regulations or the like.
Further, the front end 78a of the cut-to-raise piece 78 disposed at the vicinity of the upper end of the movable shade 30 can form the dark portion the illuminance of which is lower than that of the surrounding (illuminance reducing region) at a corresponding position of the light distribution pattern on the road face by blocking a portion of original distributed light passing the upper end edge 30aof the movable shade 30 for irradiating the road face.
Therefore, not only the dark portion having the illuminance lower than that of the surrounding is formed by the illuminance reducer 75 at an arbitrary position in the light distribution pattern PX by overhead sign irradiating light P2, but also a portion of the light distribution pattern by light irradiating the road face can be formed with the dark portion smoothly reducing the illuminance. Therefore, a higher degree of a light distribution pattern in conformity with the countermeasure against glare of the vehicle running on the opposed lane or laws or regulations or the like is easily formed.
Further, constitutions of the lamp body, the cover, the projector lens, the light source, the reflector, the shade mechanism, the reflecting face for the overhead sign, the light receiving face for the overhead sign, the illuminance reducer and the additional illuminance reducer and the like according to the vehicle headlamp of the invention are not limited to the above-described constitutions of the exemplary embodiments but various modes thereof can naturally be adopted based on the gist of the invention.
10 . . . vehicle headlamp
11 . . . projector lens
12 . . . lamp body
14 . . . transparent cover (cover)
16 . . . lamp chamber
18 . . . lamp unit
23 . . . light source bulb
23
a . . . light source
25 . . . reflector
25
a . . . reflecting face
25
b . . . reflecting face for overhead sign
28
a . . . light receiving face for overhead sign
29 . . . shade mechanism
30 . . . movable shade
31 . . . holder
44 . . . cam plate
51, 52 . . . illuminance reducer
54, 55 . . . dark portions
66 . . . swivel actuator
P1 . . . reflected light
P2 . . . overhead sign irradiating light
PL . . . light distribution pattern for low beam
PX . . . OHS light distribution pattern
While the invention has been described with reference to the exemplary embodiments and variations thereof, the technical scope of the invention is not restricted to the description of the exemplary embodiments and variations thereof. It is apparent to the skilled in the art that various changes or improvements can be made. It is apparent from the description of claims that the changed or improved configurations can also be included in the technical scope of the invention.
Number | Date | Country | Kind |
---|---|---|---|
2006-119905 | Apr 2006 | JP | national |