Patent Publication Number: US-7909493-B2

Title: Vehicle headlamp

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a vehicle headlamp, and particularly to a projector-type vehicle headlamp having a variable light distribution function which is capable of changing a light distribution of the headlamp in accordance with a driving condition of a vehicle or the like. 
     2. Background Art 
     In general, a vehicle headlamp having a projector-type lighting unit is structured to reflect light from a light source disposed on an optical axis extending in a front and rear direction of a vehicle forward so as to be close to the optical axis using a reflector, and direct the reflected light toward the front of a lamp via a projection lens provided forwardly of the reflector. 
     When the projector-type vehicle lighting unit is structured as a vehicle headlamp for passing beam (low beam) irradiation, a shade for removing upward irradiation light by blocking a part of the reflected light from the reflector is provided between the projection lens and the reflector, whereby forward beam irradiation is performed in a passing beam light distribution pattern having a predetermined cutoff line. 
     In general, since the shade of the vehicle headlamp is stationary, when the shade is set for, e.g., the passing beam light distribution pattern, the lighting unit can be used only for the passing beam and, therefore, it is impossible to switch the lighting unit to the use for a running beam (high beam). 
     Accordingly, there is proposed a vehicle lighting fixture (vehicle headlamp) in which a shade is adapted to be a movable shade movable to a passing beam position and a running beam position, an upper end edge of the shade is positioned at a focal point of a projection lens when the shade is positioned at the passing beam position, and the upper end edge is appropriately moved out of the focal point of the projection lens when the shade is positioned at the running beam position, whereby optimum light distribution characteristics as the vehicle light fixture for the passing beam and for the running beam are obtainable (see, e.g., JP-A-2006-341696). 
     The above-described shade (movable shade) of the vehicle lighting fixture described in JP-A-2006-341696 is rotatably supported inside an attachment frame, the attachment frame has a generally tubular shape and is attached to the front end part of a reflector, and a light projection lens (projection lens) is attached to an opening on the front surface. 
     In general, the attachment frame having the substantially tubular shape is formed by aluminum die casting or the like in which a melted aluminum alloy is injected into a molding die and integrally molded. In recent years, further weight reduction is required in order to improve fuel efficiency, but the weight reduction by the aluminum die casting has its limits. 
     SUMMARY OF THE INVENTION 
     One or more embodiments of the invention provide a vehicle headlamp in which a weight of a bracket for rotatably supporting a movable shade is reduced to achieve a lightweight inexpensive projector-type vehicle headlamp. 
     In accordance with one or more embodiments of the invention, a vehicle headlamp is provided with: a projection lens ( 11 ,  111 ) disposed on an optical axis (Ax) extending in a front and rear direction of a vehicle; a light source ( 23   a ,  123   a ) disposed rearwardly of a rear-side focal point (F) of the projection lens ( 11 ,  111 ); a reflector ( 25 ,  125 ) configured to reflect direct light from the light source ( 23   a ,  123   a ) forward to converge reflected light toward the optical axis (Ax); a movable shade ( 30 ,  130 ) disposed between the projection lens ( 11 ,  111 ) and the light source ( 23   a ,  123   a ) and configured to blocking a part of the reflected light from the reflector ( 25 ,  125 ) and a part of the direct light from the light source ( 23   a ,  123   a ) to form a cutoff line in a light distribution pattern; a bracket ( 32 ,  122 ) formed from a metal plate member and disposed between the projection lens ( 11 ,  111 ) and the light source ( 23   a ,  123   a ), wherein the movable shade ( 30 ,  130 ) is rotatably supported on the bracket ( 32 ,  122 ); an opening portion ( 32   a ,  122   a ) formed in the bracket ( 32 ,  122 ) and configured to pass a part of the reflected light from the reflector ( 25 ,  125 ) along the optical axis (Ax); and a shade portion ( 33 ,  133 ) provided on the opening portion ( 32   a ,  122   a ) and configured to cover a gap between the movable shade ( 30 ,  130 ) and an opening edge of the opening portion ( 32   a ,  122   a ). 
     According to the vehicle headlamp having the above-described structure, since the shade portion for covering the gap formed between the movable shade and the opening edge is provided at the opening portion of the bracket for rotatably supporting the movable shade, it is possible to prevent the leakage of the reflected light of the reflector from the gap formed between the opening portion of the bracket and the movable shade which are formed from the plate members. 
     Accordingly, since the bracket may be formed from the metal plate member, it is possible to achieve lighter weight than in the case of the formation by aluminum die casting. In addition, since the bracket may be manufactured from the metal plate member by press working or the like, it is possible to achieve lower manufacturing cost than in the case of the manufacturing by aluminum die casting. 
     In the vehicle headlamp having the above-described structure, the shade portion ( 33 ,  133 ) may be formed from a metal plate member separately from the bracket ( 32 ,  122 ), and may be fixed at an offset position which does not interfere with a movement of the movable shade ( 30 ,  130 ). 
     By the above configuration that the shade portion formed from the metal plate member separately from the bracket is fixed at the offset position which does not interfere with the movement of the movable shade, it becomes easy to form the shade portion which does not interfere with the movable shade, and it becomes possible to further reduce the manufacturing cost. 
     In addition, in the vehicle headlamp having the above-described structure, the movable shade ( 30 ,  130 ) may be supported by the bracket ( 32 ,  122 ) through a rotation shaft ( 42 ,  142 ), and the rotation shaft ( 42 ,  142 ) is fixed on the bracket by swaging. 
     According to the vehicle headlamp having such a structure, it is possible to improve attachment accuracy of the movable shade to the bracket and easily fix the movable shade to the bracket without increasing the number of parts. 
     Further, in the vehicle headlamp having the above-described structure, the movable shade ( 30 ,  130 ) may be formed from a metal plate member, a surface contact portion ( 30   c ,  130   c ) for abutting on a rear surface of the opening edge of the bracket ( 32 ,  122 ) may be formed at an each end part of the movable shade ( 30 ,  130 ) in a horizontal direction, and a reinforcement rib ( 32   e ,  132   e ) may be provided at the opening edge of the bracket ( 32 ,  122 ) on which the surface contact portion ( 30   c ,  130   c ) abuts. 
     According to the vehicle headlamp having such a structure, the stiffness and durability of the movable shade formed from the metal plate member are enhanced by the formation of the surface contact portion. In addition, since the reinforcement rib is provided at the opening edge of the bracket on which the surface contact portion of the movable shade abuts, the stiffness and durability thereof are enhanced. 
     Other aspects and advantages of the invention will be apparent from the following description, the drawings and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a longitudinal sectional view of a vehicle headlamp according to a first embodiment of the present invention; 
         FIG. 2  is an exploded perspective view of a lighting unit shown in  FIG. 1 ; 
         FIG. 3  is a longitudinal sectional view of the lighting unit shown in  FIG. 1 ; 
         FIG. 4  is an exploded rear view of a movable shade shown in  FIG. 1 ; 
         FIG. 5  is a front side perspective view of an assembly obtained by attaching the movable shade and an actuator to a bracket shown in  FIG. 1 ; 
         FIG. 6  is a rear side perspective view of the assembly obtained by attaching the movable shade and the actuator to the bracket shown in  FIG. 1 ; 
         FIG. 7  is an enlarged perspective view of a principal portion for illustrating a method for attaching the movable shade; 
         FIG. 8  is an enlarged perspective view of the principal portion for illustrating the method for attaching the movable shade; 
         FIG. 9  is a longitudinal sectional view of a vehicle headlamp according to a second embodiment of the present invention; 
         FIG. 10  is an exploded perspective view of a lighting unit shown in  FIG. 9 ; 
         FIG. 11  is an exploded perspective view of a movable shade shown in  FIG. 10 ; 
         FIG. 12  is a rear view of the movable shade shown in  FIG. 9 ; 
         FIG. 13  is a horizontal sectional view of the lighting unit shown in  FIG. 9 ; 
         FIG. 14  is a view perspectively illustrating a light distribution pattern of a running beam light distribution pattern formed on a virtual vertical screen placed at a position 25 m ahead of a lighting fixture by light irradiation from a reflector and an additional reflector shown in  FIG. 9 ; and 
         FIG. 15  is a view perspectively illustrating the light distribution pattern of a passing beam light distribution pattern formed on the virtual vertical screen placed at the position 25 m ahead of the lighting fixture by the light irradiation from the reflector and the additional reflector shown in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     A detailed description will be given hereinbelow to exemplary embodiments of a vehicle headlamp according to the present invention, on the basis of the accompanying drawings. 
       FIG. 1  is a longitudinal sectional view of a vehicle headlamp according to a first embodiment of the present invention,  FIG. 2  is an exploded perspective view of a lighting unit shown in  FIG. 1 ,  FIG. 3  is a longitudinal sectional view of the lighting unit shown in  FIG. 1 ,  FIG. 4  is an exploded perspective view of a movable shade shown in  FIG. 2 , and  FIGS. 5 and 6  are a front side perspective view and a rear side perspective view of an assembly obtained by attaching the movable shade and an actuator to a bracket shown in  FIG. 1 . 
     As shown in  FIGS. 1 and 2 , a vehicle lighting fixture  10  according to the present embodiment has a structure in which a lighting unit  18  is housed in a lamp room  16  formed by a transparent cover  14  and a lamp body  12 . 
     As shown in  FIGS. 1 and 2 , the lighting unit  18  of the present embodiment is a projector-type lighting unit, and has a projection lens  11  which is disposed on an optical axis (lens center axis) Ax extending in a front and rear direction of a vehicle, a light source bulb (discharge bulb)  23  which is disposed rearwardly of a rear-side focal point F of the projection lens  11 , a reflector  25  which reflects light (direct light) emitted from the light source bulb  23  forward so as to be close to the optical axis Ax using a light source  23   a  of the light source bulb  23  as the first focal point, a movable shade  30  which is disposed between the projection lens  11  and the light source  23   a  and blocks a part of reflected light from the reflector  25  and a part of the direct light from the light source  23   a  to form a cutoff line of a light distribution pattern, and a bracket  32  which is disposed between the projection lens  11  and the light source  23   a  and rotatably supports the movable shade  30 . 
     In addition, as shown in  FIG. 1 , the lighting unit  18  is supported by a frame  22  via the bracket  32 , and the frame  22  is supported by the lamp body  12  via an aiming mechanism which is not shown. The aiming mechanism is a mechanism for finely adjusting an attachment position and an attachment angle of the lighting unit  18 , and the optical axis Ax of the lighting unit  18  is adjusted to extend in a direction downward by about 0.5 through 0.6 degree relative to the front and rear direction of the vehicle at the point when the aiming adjustment is completed. 
     The frame  22  has a substantially rectangular shape when viewed from the front, and support plates  24  and  26  are provided to protrude forward from upper and lower sides of the frame  22 . The front end part of the support plate  24  on the upper side is provided with a bearing portion  24   a , and a supported shaft  27   a  of a coupling member  27  provided on the upper part of the lighting unit  18  is rotatably supported by the bearing portion  24   a . The support plate  26  on the lower side is formed with a circular shaft insertion hole  26   a  at a part of the front end part of the support plate  26  positioned immediately below the bearing portion  24   a . Further, a swivel actuator  71  for rotating the lighting unit  18  in a horizontal direction is fixed on the lower surface of the support plate  26  on the lower side of the frame  22 . 
     The swivel actuator  71  is driven by, e.g., reacting to a steering operation to cause an output shaft  72  to rotate. The output shaft  72  is inserted through the shaft insertion hole  26   a  of the support plate  26  and fitted into a joint portion  28  provided on the lower part of the lighting unit  18 , and the joint portion  28  is coupled to the output shaft  72 . 
     Consequently, when the swivel actuator  71  is driven, the output shaft  72  is caused to rotate and the lighting unit  18  is caused to rotate in the horizontal direction with the rotation of the output shaft  72 . 
     Because the joint portion  28  is attached to an attachment portion  32   c  after the joint portion  28  is formed separately from the bracket  32 , it is possible to appropriately replace the joint portion  28  according to specifications of the lighting unit so that flexibility of the bracket  32  is enhanced. 
     The bracket  32  press-molded from a metal plate has a substantially rectangular plate shape when viewed from the front as shown in  FIG. 4 , and is formed with an opening portion  32   a  through which the optical axis Ax passes at its central part. Swaging pieces  32   b  for fixing the coupling member  27  are provided at the upper part of the bracket  32 , and the attachment portion  32   c  for fixing the actuator  20  is provided at the lower part thereof. 
     The bracket  32  is a shade for preventing the incidence of stray light reflected by a reflecting surface  25   a  of the reflector  25  on the projection lens  11 , and the projection lens  11  is fixed on the front surface side of the bracket  32  via a lens holder  31  and the reflector  25  is fixed on the rear surface side thereof. 
     As shown in  FIGS. 3 and 4 , the movable shade  30  is press-molded from the metal plate and has a substantially rectangular plate shape, and is provided so as to be positioned in the vicinity below the optical axis Ax. At both end parts of the movable shade  30 , shaft support portions  30   b  through which a shaft  42  is rotatably inserted and abutment portions (surface contact portion)  30   c  for abutting on an opening edge of the bracket  32  at a blocking position to control the rotation are formed by bending. 
     It is to be noted that, on the opening edge of the bracket  32  on which the abutment portions  30   c  of the movable shade  30  abut, reinforcement ribs  32   e  formed by forward bending are provided. Accordingly, the stiffness and durability of the movable shade  30  formed from the metal plate member are enhanced by the formation of the abutment portions  30   c  by bending. Further, since the reinforcement ribs  32   e  formed by bending are also provided on the opening edge of the bracket  32  on which the abutment portions  30   c  of the movable shade  30  abut, the stiffness and durability thereof are enhanced. 
     The movable shade  30  is structured to be capable of taking the blocking position at which an upper end edge  30   a  is disposed so as to be positioned in the vicinity of the rear-side focal point F, and a blocking lessening position at which the blocked amount of reflected light from the reflector  25  becomes smaller than the blocked amount at the blocking position. The upper end edge  30   a  of the movable shade  30  is formed to have a lateral level difference between left and right sides thereof and, when the movable shade  30  is at the blocking position, the upper end edge  30  forms the cutoff line of a passing beam light distribution pattern. 
     In addition, as shown in  FIG. 7 , in the movable shade  30 , both end parts of the shaft  42  are set on the swaging pieces  32   d  of the bracket  32  in a state where the shaft  42  with a predetermined length is inserted through the shaft support portions  30   b  and  30   b  formed on the left and right end parts. Then, as shown in  FIG. 7 , by swaging the swaging pieces  32   d , the both end parts of the shaft  42  are fixed by the swaging on the rear surface side of the bracket  32  and the movable shade  30  is rotatably supported by the bracket  32 . 
     Accordingly, the attachment accuracy of the movable shade  30  to the bracket  32  is improved and it is possible to easily fix the movable shade  30  to the bracket  32  without increasing the number of parts. 
     To a rod engagement portion  30   d  formed by cutting and raising on the movable shade  30 , a shade-side engagement portion of a rod member  40  is coupled. A return spring  44  is wound around the shaft  42 . The return spring  44  is a metal helical torsion coil spring, and one end part thereof is engaged with the movable shade  30  and the other end part thereof is engaged with the bracket  32 . The return spring  44  is adapted to elastically bias the movable shade  30  toward the blocking position constantly. When the movable shade  30  moves to the blocking position, the abutment portions  30   c  and  30   c  formed on the both end parts abut on the rear surface of the bracket  32  to position the movable shade  30  at the blocking position. 
     By the drive of the actuator  20  coupled to an actuator-side engagement portion of the rod member  40 , the movement of the movable shade  30  between the blocking position and the blocking lessening position is performed. 
     On the front side of the movable shade  30 , an overhead sign member  35  is attached. The overhead sign member  35  is a metal plate member formed by bending so as to have a forwardly downwardly inclined surface, and the inclined surface is used as a light receiving surface for overhead sign  35   a  for reflecting reflected light P 1  from a reflecting surface for overhead sign  25   b  which will be described later toward the projection lens  11  and causing overhead sign irradiation light P 2  as upward irradiation light to be projected from the projection lens  11 . 
     As shown in  FIG. 6 , the actuator  20  is attached to the attachment portion  32   c  of the bracket  32 , and is a solenoid disposed such that the output axis  21  thereof is protruded in the rear direction of the vehicle. 
     When the operation of a beam selector switch which is not shown is performed, the actuator  20  is driven, and transmits the linear reciprocating motion of the output axis  21  thereof to the rod member  40  to cause the movable shade  30  coupled to the shade-side engagement portion of the rod member  40  to rotate. 
     The rod member  40  is formed of a wire-like member formed by bending. When the rod member  40  reciprocates along a substantially front and rear direction, the movable shade  30  having the rod engagement portion  30   d  coupled to the shade-side engagement portion performs rotation about the shaft  42  extending in a width direction of a vehicle between the blocking position and the blocking lessening position. 
     Further, as shown in  FIGS. 1 to 5 , there is provided, on the front surface of the bracket  32 , a stationary shade (shade portion)  33  which is fixed at an offset position which does not interfere with the rotation of the movable shade  30  and prevents the incidence of the stray light on the projection lens  11 . That is, although a gap for allowing the rotation of the movable shade  30  is formed between the opening portion  32   a  of the bracket  32  and the movable shade  30  which are formed from the plate members, since the stationary shade  33  is provided, it is possible to prevent the leakage of the reflected light of the reflector  25  from the gap. 
     The stationary shade  33  is formed of the metal plate member formed by bending so as to have the forwardly downwardly inclined surface, and the inclined surface is used as a light receiving surface for overhead sign  33   a  for reflecting the reflected light P 1  from the reflecting surface for overhead sign  25   b  which will be described later toward the projection lens  11  and causing the overhead sign irradiation light P 2  as the upward irradiation light to be projected from the projection lens  11 . In addition, by forming the plate metal member so as to have the forwardly downwardly inclined surface by bending, the stationary shade  33  can secure the stiffness. Further, the light receiving surface for overhead sign  35   a  is also used. 
     The projection lens  11  is constituted of a flat convex lens that has a convex surface on the front side thereof and a flat surface on the rear side thereof. As shown in  FIG. 1 , the projection lens  11  is disposed on the optical axis Ax such that the rear-side focal point F thereof is positioned at the second focal point of the reflecting surface  25   a  of the reflector  25 . With this structure, an image on the focal point surface including the rear-side focal point F is projected forward as a reverse image. 
     The light source bulb  23  is a discharge bulb having a discharge light-emitting portion as the light source  23   a  such as a metal halide bulb or the like, and the light source bulb  23  is inserted into and fixed to the rear end part of the reflector  25  in a direction in which a bulb axis is aligned with the lens center axis Ax in the case of the present embodiment. 
     A bulb socket  60  is attached to the light source bulb  23 . A power feeding cord  61  extending from the bulb socket  60  passes behind the lighting unit  18 , extends downwardly, and is connected to a lighting circuit unit (not shown) disposed at the lower part of the lamp body  12 . With this structure, a lighting voltage and a starting voltage are supplied to the light source bulb  23  from a discharge lighting circuit provided in the lighting circuit unit. 
     It is to be noted that a halogen bulb or the like may also be used instead of the discharge bulb, and the light source bulb  23  may also be inserted from the side of the reflector  25  and fixed with the bulb axis positioned in a direction substantially intersecting the lens center axis Ax. 
     It goes without saying that the concept of “a direction substantially intersecting” includes the case where the light source bulb  23  is disposed such that the optical axis thereof is orthogonal to the optical axis Ax extending in the front and rear direction of the vehicle. The concept also includes the case where the light source bulb  23  is disposed such that the optical axis thereof three-dimensionally intersects the optical axis Ar and the case where the light source bulb  23  is disposed in a state where the optical axis thereof is inclined by about ±15° relative to the horizontal line in the width direction of the vehicle. 
     The reflector  25  has the reflecting surface  25   a  of a substantially elliptical spherical shape having the optical axis As passing through the light source  23   a  as the center axis. 
     The reflecting surface  25  is set as a substantially oval-shaped elliptical reflecting surface with a cross-sectional configuration including the lens center axis Ax having the central position of the light source  23   a  as the first focal point and the vicinity of the rear-side focal point F of the projection lens  11  as the second focal point, and the reflecting surface  25   a  is adapted to reflect light from the light source  23   a  forward to converge the reflected light toward the optical axis Ax. The eccentricity of the reflecting surface  25   a  is set to be gradually increased from the vertical cross section toward the horizontal cross section. 
     As a reflecting surface continuously provided at the end part of the reflecting surface  25   a  of the reflector  25 , the reflecting surface for overhead sign  25   b  is formed integrally with the reflecting surface  25   a.    
     The reflecting surface for overhead sign  25   b  is set as a substantially oval-shaped curved surface with a cross-sectional configuration including the optical axis Ax having the central position of the light source  23   a  as the first focal point and the vicinity of the center of the light receiving surfaces for overhead sign  33   a  and  35   a  positioned slightly forwardly of the rear-side focal point F of the projection lens  11  as the second focal point, and the reflecting surface for overhead sing  25   b  is adapted to reflect and converge the light from the light source  23   a  to the light receiving surfaces for overhead sign  33   a  and  35   a . The eccentricity of the reflecting surface for overhead sign  25   b  is set to be gradually increased from the vertical cross section toward the horizontal cross section. Subsequently, the light incident on the light receiving surfaces for overhead sign  33   a  and  35   a  from the reflecting surface for overhead sign  25   b  is caused to impinge on the projection lens  11  as the upward irradiation light P 1 . 
     Next, a description will be given to the light distribution by the vehicle headlamp  10  described above. 
     As shown in  FIG. 3 , when the movable shade  30  is at the blocking position, the movable shade  30  forms the passing beam light distribution pattern having what is called a Z-shaped cutoff line with a lateral level difference between left and right sides thereof. 
     The reflected light P 1  from the reflecting surface for overhead sign  25   b  is caused to impinge on the projection lens  11  as the upward light by the light receiving surfaces for overhead sign  33   a  and  35   a , and is caused to be projected from the projection lens  11  as the overhead sign irradiation light P 2 , whereby an OHS light distribution pattern in which the overhead sign is directed above the passing beam light distribution pattern is formed. 
     According to the vehicle headlamp  10  of the present first embodiment thus described, since the stationary shade  33  for blocking the gap formed between the movable shade  30  and the opening edge is provided at the opening portion  32   a  of the bracket  32  for rotatably supporting the movable shade  30 , it is possible to prevent the leakage of the reflected light of the reflector  25  from the gap formed between the opening portion  32   a  of the bracket  32  and the movable shade  32   a  which are formed from the plate members. 
     Accordingly, since the bracket  32  may be formed from the metal plate member, it is possible to achieve lighter weight than in the case of the formation by aluminum die casting. Further, since it is possible to manufacture the bracket  32  from the metal plate member by press working or the like, it is possible to achieve lower manufacturing cost than in the case of the manufacturing by the aluminum die casting. 
     Consequently, it is possible to achieve the weight reduction of the bracket  32  for rotatably supporting the movable shade  30  and thereby provide a lightweight inexpensive projector-type vehicle headlamp  10 . 
       FIG. 9  is a longitudinal sectional view of a vehicle headlamp according to a second embodiment of the present invention,  FIG. 10  is an exploded perspective view of a lighting unit shown in  FIG. 9 ,  FIG. 11  is an exploded perspective view of a movable shade shown in  FIG. 10 ,  FIG. 12  is a rear view of the movable shade shown in  FIG. 9 , and  FIG. 13  is a horizontal sectional view of the lighting unit shown in  FIG. 9 . 
     As shown in  FIGS. 9 and 10 , a vehicle lighting fixture  100  according to the present embodiment has a structure in which a lighting unit  118  is housed in a lamp room  116  formed by a transparent cover  114  and a lamp body  112 . 
     The lighting unit  118  is supported by the lamp body  112  via a bracket  122 , and the bracket  122  is supported by the lamp body  112  via an aiming mechanism  160 . 
     The aiming mechanism  160  is a mechanism for finely adjusting the attachment position and angle of the lighting unit  118 , and the optical axis (lens center axis) Ax of the lighting unit  118  is adjusted to extend in a direction downward by about 0.5 through 0.6 degree relative to the front and rear direction of the vehicle at the point when the aiming adjustment is completed. 
     The bracket  122  press-molded from a metal plate has a substantially rectangular plate shape when viewed from the front as shown in  FIG. 3 , and is provided with a central opening portion  122   a  through which the optical axis Ax passes and three attachment holes  122   b  to which bearing members  161  to be engaged with one end of an aiming screw  163  in the aiming mechanism  160  are attached. 
     The bracket  122  is a shade for preventing the incidence of stray light reflected by a reflecting surface  125   a  of a reflector  125  on a projection lens  111 , and the projection lens  111  is fixed on the front surface side of the bracket  122  via a lens holder  131  and the reflector  125  is fixed on the rear surface side thereof. 
     As shown in  FIGS. 11 and 13 , a control member  146  for controlling reflected light by blocking a part of direct light traveling from a halogen bulb  123  toward an additional reflector  128  is provided on the rear surface side at the lower part of the bracket  122 . 
     As shown in  FIGS. 9 and 10 , the lighting unit  118  of the present embodiment is a projector-type lighting unit, and includes the projection lens  111  which is disposed on the optical axis Ax extending in the front and rear direction of the vehicle, the halogen bulb  123  which is disposed rearwardly of the rear-side focal point F of the projection lens  111 , the reflector  125  which reflects the direct light emitted from the halogen bulb  123  forward so as to converge the light toward the optical axis Ax with a light source  123   a  of the halogen bulb  123  as the first focal point, a movable shade  130  which is disposed between the projection lens  111  and the halogen bulb  123  and blocks a part of reflected light L 1  from the reflector  125  and a part of the direct light from the halogen bulb  123  to form the cutoff line of the light distribution pattern, an actuator  120  which moves the movable shade  130  between the blocking position disposed such that an upper end edge  130   a  is positioned in the vicinity of the rear-side focal point F of the projection lens  111  and the blocking lessening position at which the blocked amount of the reflected light L 1  from the reflector  125  becomes smaller than the blocked amount at the blocking position, and the additional reflector  128  which is disposed below the optical axis Ax, and diffuses and reflects the direct light from the halogen bulb  123  forward without allowing the direct light to pass through the projection lens  111 . 
     The projection lens  111  is constituted of a flat convex lens that has a convex surface on the front side thereof and a flat surface on the rear side thereof. As shown in  FIG. 9 , the projection lens  111  is disposed on the optical axis Ax such that the rear-side focal point F thereof is positioned at the second focal point of the reflecting surface  125   a  of the reflector  125 . With this structure, an image on the focal point surface including the rear-side focal point F is projected forward as a reverse image. 
     It is to be noted that, as the projection lens  111  of the present embodiment, a projection lens having an effective surface of 80 mm in diameter is used instead of a normal lens having the effective surface of about 60 mm in diameter. Accordingly, by making a focal length longer and a light source image smaller, it is possible to improve a light amount and a light ray bundle of the lighting unit  118 . 
     In addition, the surface of the projection lens  111  is formed with a microstructure. Accordingly, the projection lens  111  may suppress the reduction in visibility caused by an excessive degree of contrast between brightness and darkness of a cutoff line CL of the lighting unit  118  having enhanced light gathering power. 
     The halogen bulb  123  is structured as a line segment light source in which the light source  123   a  extends in a direction of a bulb center axis, and is inserted from the side of the reflector  125  and fixed in a direction which causes the bulb axis to substantially intersect the optical axis Ax at a position downwardly apart from the optical axis Ax. 
     The reflector  125  has reflecting surfaces  125   a ,  125   b , and  125   c  which form a hot zone (high brightness zone) HZ required for a running beam light distribution pattern PH by reflecting light from the light source  123   a  forward so as to converge the light toward the optical axis Ax (see  FIG. 14 ). 
     The reflecting surface  125   a  is an elliptical reflecting surface which is formed into a substantially oval shape and has the position of the light source  123   a  as the first focal point and the rear-side focal point F of the projection lens  111  as the second focal point in a vertical cross section thereof including the optical axis Ax, and the eccentricity thereof is set to be gradually increased from the vertical cross section toward the horizontal cross section. 
     With this structure, the light L 1  from the light source  123   a  reflected by the reflecting surface  125   a  is caused to substantially converge in the vicinity of the rear-side focal point F in the vertical cross section, and the position of the convergence is caused to move considerably forward in the horizontal cross section, whereby a diffusion pattern HZA in the hot zone HZ is formed. 
     The reflecting surface  125   b  shown in  FIG. 9  is provided outside the effective reflecting surface in the upper part of the reflector  125 , and is adapted to form a converging light pattern HZB in which reflected light L 2  is directed to the lower part of the diffusion pattern HZA by the reflected light L 1  of the reflecting surface  125   a.    
     That is, as shown in  FIG. 14 , the reflecting surfaces  125   a  and  125   b  of the reflector  125  form the hot zone HZ required for the running beam light distribution pattern PH by combining the diffusion pattern HZA and the converging light pattern HZB by their respective reflected light L 1  and L 2 . 
     In addition, as shown in  FIG. 13 , the reflecting surface  125   c  positioned immediately lateral to and above the optical axis Ax is a diffusing surface formed at a part of the reflecting surface of the reflector  125  positioned immediately lateral to the optical axis Ax, and is capable of easily obtaining diffused light L 3  in a lateral direction. 
     As shown in  FIG. 10 , the additional reflector  128  is disposed below the reflector  125  and includes inside reflecting surfaces  150 , outside reflecting surfaces  151 , and a reflecting surface for overhead sign  152  which diffuse and reflect a part of the direct light from the halogen bulb  123  forward without allowing the part of the direct light to pass through the projection lens  111 . 
     The inside reflecting surfaces  150  disposed on the left and the right of the optical axis Ax are parabolic reflecting surfaces extending in the front and rear direction of the vehicle along the optical axis Ax, and form a first diffusion pattern WZA spread laterally below the cutoff line. 
     The outside reflecting surfaces  151  extending in the front and rear direction of the vehicle on both sides of the inside reflecting surfaces  150  are parabolic reflecting surfaces which form a second diffusion pattern WZB spread in a lateral direction below the cutoff line more widely than in the case of the inside reflecting surfaces  150 . Further, the outside reflecting surfaces  151  are formed so as to be apart from the optical axis Ax as they go in a forward direction and are formed to make an acute angle with respect to a vertical plane including the optical axis Ax. 
     Further, the reflecting surface for overhead sign  152  disposed at the front end part of the additional reflector  28  forms a light distribution pattern OZ for OHS irradiation in which the overhead sign (OHS) is directed by upwardly reflecting direct light L 6  of the halogen bulb  23 . 
     As shown in  FIGS. 11 and 12 , the movable shade  130  is press-molded from a metal plate and has a substantially rectangular plate shape, and is provided so as to be positioned in the vicinity below the optical axis Ax. On both end parts of the movable shade  130 , shaft support portions  130   b  through which a shaft  142  is rotatably inserted, and abutment portions (surface contact portions)  130   c  for abutting on the bracket  122  to control the rotation at the blocking position are formed by bending. 
     At the opening edge of the bracket  122  on which the abutment portions  130   c  of the movable shade  130  abut, reinforcement ribs  132   e  formed by forward bending are provided. Accordingly, the stiffness and durability of the movable shade  130  formed from the metal plate member are enhanced by the formation of the abutment portions  130   c  by bending. In addition, since the reinforcement ribs  132   e  formed by bending are also provided at the opening edge of the bracket  122  on which the abutment portions  130   c  of the movable shade  130  abut, the stiffness and durability are also enhanced. 
     The movable shade  130  is adapted to be capable of taking the blocking position at which the upper end edge  130   a  is positioned in the vicinity of the rear-side focal point F and the blocking lessening position at which the blocked amount of the reflected light from the reflector  125  becomes smaller than the blocked amount at the blocking position. The upper end edge  130   a  of the movable shade  130  is formed to have a lateral level difference between left and right sides thereof, and forms the cutoff line CL of a passing beam light distribution pattern PL when the movable shade  130  is at the blocking position (see  FIG. 15 ). 
     The part of the upper end edge  130   a  which forms the cutoff line in the vicinity of an oncoming vehicle is formed with a protrusion part protruding as it goes to the end part. The protrusion part prevents the glare to the oncoming vehicle by preliminarily blocking the light distribution pattern in the vicinity of the oncoming vehicle which may be upwardly leaked due to lens aberration of the projection lens  111 . 
     As shown in  FIGS. 11 and 13 , the movable shade  130  is rotatably supported by the bracket  122  by fixing both end parts of the shaft  142  on the rear surface side using swaging pieces of the bracket  122  by swaging in a state where the shaft  142  of a predetermined length is inserted into insertion holes of shaft support portions  130   b  and  130   b  formed on the left and right end parts. 
     On the front surface of the bracket  122  which is the opposite surface of the rear surface on which the movable shade  130  is fixed, a stationary shade (shade portion)  133  for preventing the incidence of the stray light on the projection lens  111  while permitting the rotation of the movable shade  130  is provided. That is, a gap for allowing the rotation of the movable shade  130  is formed between the opening portion  122   a  of the bracket  122  and the movable shade  130  which are formed from the plate members. However, it is possible to prevent the leakage of the reflected light of the reflector  125  from the gap by providing the stationary shade  133 . 
     An upper end engagement part of a rod member  140  is coupled to a rod engagement portion  130   d  formed by cutting and raising in the central part of the movable shade  130 . A notch hole formed by forming the rod engagement portion  130   d  by cutting and raising is covered with a shading piece  130   e  to prevent leaked light. 
     In addition, at the central part of the lower end edge of the movable shade  130 , a stopper piece  130   f  is provided to be protruded rearward. The stopper piece  130   f  controls the range of the rotation by abutting on the stationary shade  133  at its tip part when the movable shade  130  is rotated to be at the blocking lessening position. 
     A return spring  144  is wound around the shaft  142 . The return spring  144  is a metal helical torsion coil spring, and one end part thereof is engaged with the movable shade  130  and the other end part thereof is engaged with the stationary shade  133  attached to the bracket  122 . The return spring  44  is adapted to elastcally bias the movable shade  130  toward the blocking position constantly. When the movable shade  130  moves to the blocking position, the abutment portions  130   c  and  130   c  formed on the both end parts abut on the rear surface of the bracket  122  to position the movable shade  130  at the blocking position. 
     By the drive of an actuator  120  coupled to an lower end engagement portion of the rod member  140 , the movement of the movable shade  130  between the blocking position and the blocking lessening position is performed. 
     The actuator  120  is a solenoid disposed such that an output axis  121  thereof is obliquely and downwardly protruded in a front direction of the vehicle below the additional reflector  128 . The actuator  120  is screwed to the lower part of the reflector  125  positioned below the additional reflector  128 . 
     The actuator  120  is driven when the operation of the beam selector switch which is not shown is performed, and transmits the linear reciprocating motion of the output axis  121  thereof to the rod member  140  via a rotation plate  155  of an operating direction conversion mechanism  153  to cause the movable shade  130  coupled to the upper end engagement portion of the rod member  140  to rotate. 
     The rod member  140  is constituted of a wire-like member formed by bending the upper and lower engagement portions thereof into an L shape. Accordingly, when the rod member  140  reciprocates along a substantially vertical direction, the movable shade  130  having the rod engagement portion  130   d  coupled to the upper end engagement portion performs rotation between the blocking position and the blocking lessening position about the shaft  142  extending in the width direction of the vehicle. 
     Next, a description will be given to an optical action of the movable shade  130 . 
     As shown in  FIGS. 9 and 13 , in a state where the movable shade  130  is at the blocking position, the upper end edge  130   a  thereof for forming the cutoff line CL on the passing beam light distribution pattern PL is disposed so as to pass through the rear-side focal point F of the projection lens  111 . With this structure, a part of the reflected light L 1  from the reflecting surface  125   a  of the reflector  125  is blocked and most of the upward light projected forward from the projection lens  111  is removed. 
     The reflected light L 4  and L 5  of the inside reflecting surfaces  150  and the outside reflecting surfaces  151  in the additional reflector  128  are directed forward irrespective of the position of the movable shade  130 . 
     Subsequently, by combining the reflected light L 1  of the reflecting surface  125   a  in the reflector  125  and the reflected light L 4  and L 5  of the inside reflecting surfaces  150  and the outside reflecting surfaces  151  in the additional reflector  128 , the passing beam light distribution pattern PL for left hand traffic having what is called the Z-shaped cutoff line CL having a lateral level difference between left and right sides thereof shown in  FIG. 15  is formed. 
     On the other hand, when the movable shade  130  moves from the blocking position to the blocking lessening position, the upper end edge  130   a  thereof is obliquely and downwardly displaced in the rearward direction, and the blocked amount of the reflected light L 1  from the reflecting surface  125   a  of the reflector  125  is reduced. In the present embodiment, the blocked amount of the reflected light from the reflecting surface  125   a  is reduced to be substantially zero. 
     Subsequently, by combining the reflected light L 1  of the reflecting surface  125   a  in the reflector  125  and the reflected light L 4  and L 5  of the inside reflecting surfaces  150  and the outside reflecting surfaces  151  in the additional reflector  128 , the running beam light distribution pattern PH shown in  FIG. 14  is formed. 
     That is, in accordance with the vehicle headlamp  100  of the present second embodiment thus described, since the stationary shade  133  for covering the gap formed between the movable shade  130  and the opening edge is provided at the opening portion  122   a  of the bracket  122  for rotatably supporting the movable shade  130 , it is possible to prevent the leakage of the reflected light of the reflector  125  from the gap formed between the opening portion  122   a  of the bracket  122  and the movable shade  130  which are formed from the plate members. 
     Accordingly, since the bracket  122  may be formed from the metal plate member, it is possible to achieve lighter weight than in the case of the formation by aluminum die casting. In addition, since the bracket  122  may be manufactured from the metal plate member by press working or the like, it is possible to achieve lower manufacturing cost than in the case of the manufacturing by the aluminum die casting. 
     Therefore, it is possible to achieve the weight reduction of the bracket  122  for rotatably supporting the movable shade  130  and thereby provide the lightweight inexpensive projector-type vehicle headlamp  100 . 
     The vehicle headlamp of the present invention is not limited to the structure in each of the above-described embodiments, and may naturally adopt various modes based on the gist of the invention. For example, when the halogen bulb is used instead of the discharge bulb, because a control circuit or the like can be omitted, it is possible to provide an inexpensive projector-type vehicle headlamp with a further reduced weight. 
     For example, in the above-described embodiments, after the stationary shade  33  ( 133 ) is formed separately from the bracket  32  ( 122 ), the stationary shade is fixed at the offset position which does not interfere with the movement of the movable shade  30  ( 130 ). However, the shade portion may be preliminarily formed integrally with the bracket. 
     DESCRIPTION OF REFERENCE NUMERALS AND SIGNS 
     
         
           10  . . . vehicle headlamp 
           11  . . . projection lens 
           12  . . . lamp body 
           14  . . . transparent cover (cover) 
           18  . . . lighting unit 
           20  . . . actuator 
           23  . . . light source bulb (discharge bulb) 
           25  . . . reflector 
           25   a  . . . reflecting surface 
           25   b  . . . reflecting surface for overhead sign 
           30  . . . movable shade 
           30   a  . . . upper end edge 
           30   b  . . . shaft support portion 
           30   c  . . . abutment portion (surface contact portion) 
           31  . . . lens holder 
           32  . . . bracket 
           32   a  . . . opening portion 
           33  . . . stationary shade (shade portion) 
           40  . . . rod member 
         Ax . . . optical axis