Abstract:
There is provided a vehicle headlight. The vehicle headlight includes: a light source configured to emit light; a reflector reflecting the light; a projection lens projecting the light; a stationary shade blocking a part of the light emitted from the light source; a movable shade supported by the stationary shade as to move between a shielding position and a non-shielding position and configured to block a part of the light emitted from the light source; a drive mechanism including: a yoke; a coil disposed in the yoke; and an output shaft configured to move in an axial direction thereof in response to current supplied to the coil, and a transmission mechanism transmitting a driving force of the drive mechanism to the movable shade. At least a part of the yoke of the drive mechanism is formed in a single piece with the stationary shade.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority from Japanese Patent Application No. 2010-249442, filed on Nov. 8, 2010, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates to a vehicle headlight. More particularly, the present disclosure relates to a technique that reduces the size of a vehicle headlight and the number of components of the vehicle headlight by integrally forming a yoke of a drive mechanism, which rotates a movable shade, with a stationary shade that blocks a part of light emitted from a light source. 
         [0004]    2. Related Art 
         [0005]    As a vehicle headlight, there is, for example, a vehicle headlight where a lamp unit including a light source is disposed in a lamp casing formed of a cover and a lamp housing. 
         [0006]    As a lamp unit of a vehicle headlight, there is a lamp unit that includes a stationary shade and a movable shade and can switch the irradiation mode of light emitted from a light source by the rotation of the movable shade relative to the stationary shade (for example, see JP-A-2009-230958). 
         [0007]    In the vehicle headlight disclosed in JP-A-2009-230958, for example, a mode is switched to a so-called low-beam irradiation mode irradiating at a short distance when the movable shade is rotated to a shielding position where the movable shade blocks light emitted from the light source, and a mode is switched to a so-called high-beam irradiation mode irradiating at a long distance when the movable shade is rotated to a non-shielding position where the movable shade does not block light emitted from the light source. 
         [0008]    The vehicle headlight disclosed in JP-A-2009-230958 is provided with a drive mechanism for rotating the movable shade, and the drive mechanism is formed of an electromagnetic actuator that includes a coil, a yoke, and an output shaft. Accordingly, as current is supplied to the coil of the electromagnetic actuator and the supply of current to the coil of the electromagnetic actuator is stopped, the movable shade is rotated between the shielding position and the non-shielding position. 
         [0009]    Meanwhile, it is preferable that the size of a vehicle headlight including a lamp unit be reduced. In particular, in recent years, there has been a demand for the further reduction of the size of a vehicle headlight that is accompanied by the shortening of the focal length of an optical system provided in a vehicle headlight. 
         [0010]    Further, it is preferable that the structure of a vehicle headlight also be simple, and it is preferable that the number of components of the vehicle headlight be reduced. 
         [0011]    Meanwhile, in the vehicle headlight disclosed in JP-A-2009-230958, a drive mechanism for rotating the movable shade relative to the stationary shade is disposed below the stationary shade. For this reason, the height of a beam switching structure, which includes the stationary shade and the movable shade, in the up-down direction is particularly large and it is difficult to reduce the size of the vehicle headlight. 
       SUMMARY OF THE INVENTION 
       [0012]    Exemplary embodiments of the present invention may address the above disadvantages and other disadvantages not described above. However, the present invention is not required to overcome the disadvantages described above, and thus, an exemplary embodiment of the present invention may not overcome any disadvantages. 
         [0013]    One of illustrative aspects of the present invention is to overcome the above-mentioned problem and to reduce the size of a vehicle headlight and the number of components of the vehicle headlight. 
         [0014]    According to one or more illustrative aspects of the present invention, there is provided a vehicle headlight. The vehicle headlight comprises: a lamp casing and a lamp unit disposed in the lamp casing. The lamp casing comprises: a lamp housing, wherein at least one surface of the lamp housing is opened; a cover attached to the lamp housing to cover the at least one surface of the lamp housing. The lamp unit comprises: a light source configured to emit light; a reflector comprising a reflective surface that reflects the light emitted from the light source; a projection lens that projects the light emitted from the light source toward a forward area; a stationary shade disposed between the projection lens and the light source and configured to block a part of the light emitted from the light source; a movable shade supported by the stationary shade as to move between a shielding position and a non-shielding position and configured to block a part of the light emitted from the light source when the movable shade is located in the shielding position; a drive mechanism configured to rotate the movable shade, the drive mechanism comprising: a yoke; a coil disposed in the yoke; and an output shaft configured to move in an axial direction thereof in response to current supplied to the coil, and a transmission mechanism configured to transmit a driving force of the drive mechanism to the movable shade. At least a part of the yoke of the drive mechanism is formed in a single piece with the stationary shade. 
         [0015]    Accordingly, it may be possible to reduce the size of the vehicle headlight and the number of components of the vehicle headlight. 
         [0016]    According to one or more illustrative aspects of the present invention, an optical axis of the light source is located between a middle of the yoke in a left-right direction thereof and a rotation center of the movable shade in a left-right direction orthogonal to a longitudinal direction of the vehicle headlamp. 
         [0017]    Accordingly, it may be possible to make the barycenter of the lamp unit be close to the middle of the stationary shade in the left-right direction and to improve vibration resistance. 
         [0018]    According to one or more illustrative aspects of the present invention, the yoke comprises: a plurality of surface portions, and the yoke comprises: an integrated yoke portion formed in a single piece with the stationary shade; and a separate yoke portion connected to the integrated yoke portion and formed separately from the stationary shade. Each of the integrated yoke portion and the separate yoke portion comprises at least two surface portions of the surface portions. 
         [0019]    Accordingly, it may be possible to easily form the yoke by joining the separate yoke portion to the integrated yoke portion. 
         [0020]    According to one or more illustrative aspects of the present invention, the yoke forms a closed magnetic path portion formed in a rectangular frame and having an opening in a longitudinal direction of the vehicle headlamp, the closed magnetic path portion having four surface portions of the surface portions. The four surface portions of the closed magnetic path portion has: a first side surface portion; a lower surface portion; a second side surface portion; and an upper surface portion. The integrated yoke portion comprises: the first side surface portion; and the lower surface portion, and the separate yoke portion comprises: the second side surface portion; and the upper surface portion. 
         [0021]    Accordingly, it may be possible to increase the driving force of the drive mechanism by the closed magnetic path portion and to easily form the closed magnetic path portion by joining the separate yoke portion to the integrated yoke portion. 
         [0022]    According to one or more illustrative aspects of the present invention, either the integrated yoke portion or the separate yoke portion further comprises a front surface portion configured to cover the opening of closed magnetic path portion. 
         [0023]    Accordingly, not only the closed magnetic path portion but also the front surface portion contributes to the increase of the driving force of the drive mechanism and the inner structure of the yoke is not seen from the outside of the cover. Therefore, it may be possible to improve the appearance of the yoke. 
         [0024]    Other aspects and advantages of the present invention will be apparent from the following description, the drawings and the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a schematic view showing a vehicle headlight according to an embodiment of the invention: 
           [0026]      FIG. 2  is an exploded perspective view of a lamp unit; 
           [0027]      FIG. 3  is a perspective view showing a stationary shade and a yoke; 
           [0028]      FIG. 4  is a perspective view showing a movable shade located at a shielding position; 
           [0029]      FIG. 5  is a front view showing the movable shade located at a non-shielding position; 
           [0030]      FIG. 6  is a perspective view showing a coil, a coil bobbin, a disposition case, and respective components disposed in the disposition case; and 
           [0031]      FIG. 7  is a perspective view of a reflector and the like when seen from the back side. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    Exemplary embodiments of the invention will be described below with reference to the drawings. The same or equivalent elements, members, and processes, which are shown in the respective drawings, are denoted by the same reference numerals, and repeated description thereof will be appropriately omitted. Further, the embodiments are illustrative and do not limit the invention. The characteristics or combinations described in the embodiments are not necessarily essential in the invention. 
         [0033]    A vehicle headlight according to a preferred embodiment of the invention will be described below with reference to the accompanying drawings. 
         [0034]    Vehicle headlights  1  are disposed and mounted on both left and right end portions of the front end portion of a vehicle body. 
         [0035]    As shown in  FIG. 1 , the vehicle headlight  1  includes a lamp housing  2  and a cover  3 . The lamp housing  2  includes a recess that is opened to the front side, and the cover  3  closes the opening of the lamp housing  2 . A lamp casing  4  is formed of the lamp housing  2  and the cover  3 , and an inner space of the lamp casing  4  is formed as a lamp chamber  5 . 
         [0036]    A mounting hole  2   a , which is opened in a front-rear direction, is formed at a rear end portion of the lamp housing  2 . A back cover  6  is mounted at the mounting hole  2   a.    
         [0037]    A lamp unit  7  is disposed in the lamp chamber  5  (see  FIGS. 1 and 2 ). The lamp unit  7  includes a lens holder  8 , a projection lens  9  that is mounted on the front end portion of the lens holder  8 , a reflector  10  that is positioned on the rear side of the lens holder  8 , and a light source  11  that is mounted on the rear end portion of the reflector  10 . For example, a discharge lamp is used as the light source  11 . 
         [0038]    The lens holder  8  includes a cylindrical lens mounting portion  8   a  that is opened in the front-rear direction; and a plurality of mounting leg portions  8   b ,  8   b , . . . that are spaced apart from each other in a circumferential direction and protrude rearward from the lens mounting portion  8   a.    
         [0039]    The inner surface of the reflector  10  is formed as a reflective surface  10   a . A fastening portion  10   b , which protrudes outward, is formed at the reflector  10 . 
         [0040]    The lens holder  8  and a stationary shade  12  are mounted on the fastening portion  10   b  of the reflector  10  in this order from the front side by, for example, screwing or the like. The stationary shade  12  is formed in the shape of a plate facing the front-rear direction, and both left and right side portions of the stationary shade are formed as mounted portions  12   a  and  12   a , which are mounted on the fastening portion  10   b  of the reflector  10 , as shown in  FIGS. 2 and 3 . 
         [0041]    A light transmission hole  13  is formed at the stationary shade  12 . The light transmission hole  13  includes a horizontally long first portion  13   a  and a continuous second portion  13   b  that is formed at a portion of the lower end of the first portion  13   a  except for both left and right portions. The second portion  13   b  is formed substantially in the shape of a circular arc of which an opening edge is convex downward. 
         [0042]    A support hole  12   b  is formed at the stationary shade  12  at the position that is near the left end of the stationary shade  12  and immediately below the light transmission hole  13 . An insertion hole  12   c  is formed at the lower end portion of the left end portion of the stationary shade  12 . 
         [0043]    A stopper piece  12   d , which protrudes forward, is formed at the lower opening edge of the light transmission hole  13  at the position that is near the right end of the stationary shade  12 . 
         [0044]    A connecting plate portion  14 , which protrudes obliquely forward and downward, is formed integrally with the lower end portion of the stationary shade  12 . 
         [0045]    The rear end portions of the mounting leg portions  8   b ,  8   b , . . . of the lens holder  8  are joined to the mounted portions  12   a  and  12   a  of the stationary shade  12  from the front side, and the mounting leg portions  8   b ,  8   b , . . . and the mounted portions  12   a  and  12   a  are joined to the fastening portion  10   b  of the reflector  10  by screwing or the like (see  FIG. 2 ). 
         [0046]    A movable shade  15  is rotatably supported on the front surface of the stationary shade  12  (see  FIGS. 2 ,  4 , and  5 ). The movable shade  15  includes a plate-like light blocking portion  16  that extends substantially in the left-right direction, and a plurality of weights  17 ,  17 , . . . that are mounted on the front surface of the left end portion of the light blocking portion  16 . 
         [0047]    A supported shaft  16   a , which protrudes rearward, is formed on the light blocking portion at the position near the left end of the light blocking portion  16 . A connecting piece  16   b , which protrudes forward, is formed at the left end portion of the light blocking portion  16 . 
         [0048]    The supported shaft  16   a  of the light blocking portion  16  is inserted into the support hole  12   b  of the stationary shade  12  from the front side, so that the movable shade  15  is connected to the stationary shade and can be rotated relative to the stationary shade  12  about the supported shaft  16   a  as a fulcrum. The supported shaft  16   a  of the movable shade  15  is positioned near the right ends of the weights  17 ,  17 , . . . . A balance hole  16   c  is formed at the light blocking portion  16  of the movable shade  15 . The balance hole  16   c  is formed at a portion of the light blocking portion that overlaps with the stationary shade  12  in the front-rear direction even when the movable shade  15  is at any position in a rotation range. Accordingly, the balance hole  16   c  does not overlap with the light transmission hole  13 , which is formed at the stationary shade  12 , in the rotation range of the movable shade  15 . 
         [0049]    The movable shade  15  is adapted to be capable of being rotated between a shielding position (see  FIG. 4 ) where the second portion  13   b  of the light transmission hole  13  formed at the stationary shade  12  is closed and a non-shielding position (see  FIG. 5 ) where the second portion  13   b  is opened. The rotation of the movable shade  15  is restricted by the stopper piece  12   d  formed at the stationary shade  12 , so that the movable shade  15  is held at the shielding position. 
         [0050]    The vehicle headlight  1  is provided with a pushing spring (not shown) that pushes the movable shade  15  in a rotational direction from the non-shielding position toward the shielding position. When a rotating force in the direction from the non-shielding position toward the shielding position is not applied to the movable shade  15 , the movable shade  15  is pressed against the stopper piece  12   d  formed at the stationary shade  12  by the pushing force of the pushing spring. Accordingly, the rotation of the movable shade  15  is restricted, so that the movable shade  15  is held at the shielding position. 
         [0051]    When the movable shade  15  is rotated to the shielding position, a part of the light emitted from the light source  11  is blocked by the stationary shade  12  and the movable shade  15 . Accordingly, a mode is switched to a so-called low-beam irradiation mode that irradiates at a short distance. Further, when the movable shade  15  is rotated to the non-shielding position, a part of the light emitted from the light source  11  is blocked by only the stationary shade  12 . Accordingly, a mode is switched to a so-called high-beam irradiation mode that irradiates at a long distance. 
         [0052]    Meanwhile, when vibration is generated at the vehicle headlight  1 , there is a concern that a rotating force in the rotational direction from the shielding position toward the non-shielding position is applied to the movable shade  15 . However, the movable shade  15  is provided with the weights  17 ,  17 , . . . as described above. Accordingly, rotational moment in the rotational direction toward the non-shielding position is reduced by the weights  17 ,  17 , . . . , so that it may be possible to prevent the movable shade  15  from being unnecessarily rotated toward the non-shielding position when vibration is generated. 
         [0053]    Further, since the weights  17 ,  17 , . . . have a function of generating a rotating force in the same direction as the direction where the pushing force of the pushing spring is applied, the size of the pushing spring may be reduced by that much. This contributes to the reduction of the size of the vehicle headlight  1 . 
         [0054]    Furthermore, since the balance hole  16   c  formed at the movable shade  15  also has the same function as the weights  17 ,  17 , . . . , it may be possible to prevent the movable shade  15  from being unnecessarily rotated toward the non-shielding position when vibration is generated and the size of the pushing spring may be reduced. This contributes to the reduction of the size of the vehicle headlight  1 . 
         [0055]    In addition, since the balance hole  16   c  is formed, the mass of the weights  17 ,  17 , . . . may be reduced. Accordingly, it may be possible to reduce the weight of the vehicle headlight  1 . 
         [0056]    The movable shade  15  is rotated by a drive mechanism  18 . For example, an electromagnetic actuator is used as the drive mechanism  18 , and the drive mechanism  18  includes a yoke  19 , a coil bobbin  20 , a coil  21 , and an output shaft  22 . 
         [0057]    The yoke  19  includes an integrated yoke portion  23  that is formed integrally with the stationary shade  12 , and a separate yoke portion  24  that is joined to the integrated yoke portion  23  and formed separately from the stationary shade  12 . 
         [0058]    The integrated yoke portion  23  includes, for example, a lower surface portion  25  and a side surface portion  26  that protrudes upward from one side edge of the lower surface portion  25 . The rear edge of the lower surface portion  25  is connected to the front edge of the connecting plate portion  14 . Joint grooves  25   a ,  26   a , and  26   a  are formed at the other side edge of the lower surface portion  25  and the upper and front edges of the side surface portion  26 , respectively. 
         [0059]    The separate yoke portion  24  includes an upper surface portion  27 , a side surface portion  28  that protrudes upward from one side edge of the upper surface portion  27 , and a front surface portion  29  that protrudes downward from the front edge of the upper surface portion  27 . One side edge of the front surface portion  29  and the front edge of the side surface portion  28  are connected to each other. Joint protrusions  27   a ,  28   a , and  29   a  are formed at the other side edge of the upper surface portion  27 , the lower edge of the side surface portion  28 , and one side edge of the front surface portion  29 , respectively. A shaft insertion hole  28   b  is formed at the central portion of the side surface portion  28 . 
         [0060]    The joint protrusions  27   a ,  28   a , and  29   a  are inserted into the joint grooves  26   a ,  25   a , and  26   a , respectively, and the separate yoke portion  24  is joined to the integrated yoke portion  23  by adhesion or the like. When the separate yoke portion  24  is joined to the integrated yoke portion  23 , a yoke  19  having the shape of a horizontally long box opened to the rear side is formed. The separate yoke portion  24  functions as a cover that covers the respective portions disposed in the yoke  19 . 
         [0061]    The width of the side surface portion  28  in the front-rear direction is smaller than that the width of the upper surface portion  27  in the front-rear direction, so that the rear edge of the side surface portion  28  is positioned on the front side of the rear edge of the upper surface portion  27 . 
         [0062]    A closed magnetic path portion  30  is formed in the yoke  19 . The closed magnetic path portion  30  is formed in the shape of a bar, which has a rectangular cross-section, by the lower surface portion  25 , the upper surface portion  27 , and the side surface portions  26  and  28  so as to be opened in the front-rear direction. A clearance recess  19   a  is formed at the upper end portion of the front end portion of the yoke  19 . 
         [0063]    When light is emitted from the light source  11  in the vehicle headlight  1 , downward light exists in the light transmitted through the light transmission hole  13  of the stationary shade  12 . However, it may be possible to secure a good irradiation state of light by the clearance recess  19   a  without irradiating the yoke  19  with the downward light. Further, since a portion, which secures a good irradiation state of light, is the recess (clearance recess  19   a ), it may be possible to reduce the influence of the yoke  19  on a magnetic path as compared to when a clearance hole is formed in order to secure a good irradiation state of light. 
         [0064]    The yoke  19  is positioned on the front side of the stationary shade  12 , the middle M of the yoke in the left-right direction is positioned on the right side of an optical axis P of the light source  11 , and a rotation center S of the movable shade  15  is positioned on the left side of the optical axis P of the light source  11  (see  FIG. 5 ). That is, the middle M of the yoke  19  in the left-right direction and the rotation center S of the movable shade  15  are positioned on the opposite sides of the light source  11  in the left-right direction. 
         [0065]    As shown in  FIGS. 2 and 6 , the coil bobbin  20  includes a cylindrical portion  31  that extends in the left-right direction and pressing portions  32  and  32  that provided at both left and right end portions of the cylindrical portion  31 , respectively. Each of the pressing portions  32  and  32  is formed in the shape of a plate facing the left-right direction, and a shaft insertion hole  32   a  is formed at the pressing portion  32  that is positioned on at least the left side. 
         [0066]    A disposition case  33 , which protrudes to the left side, is mounted on the rear end portion of the pressing portion  32  that is positioned on the left side. The disposition case  33  is formed in the shape of a box opened to the rear side, and the inside of the disposition case is formed as a disposition space  33   a . The right end portion of the disposition case  33  is formed as a connecting portion  34  of which the outer shape is smaller than other portions. 
         [0067]    The coil  21  is externally mounted on the cylindrical portion  31  of the coil bobbin  20 . The coil bobbin  20  on which the coil  21  has been mounted is disposed in the yoke  19 , and the disposition case  33  is positioned so as to protrude from the yoke  19  to the left side. In this case, the connecting portion  34  of the disposition case  33  is positioned on the rear side of the side surface portion  28  of the yoke  19 . 
         [0068]    A connecting groove  22   a , which extends in the circumferential direction, is formed on the output shaft  22  at the position near the left end of the output shaft (see  FIGS. 2 ,  4 , and  5 ). The right end portion of the output shaft  22  is inserted into the cylindrical portion  31  through the shaft insertion hole  28   b  that is formed at the side surface portion  28  of the yoke  19  and the shaft insertion hole  32   a  that is formed at the pressing portion  32  of the coil bobbin  20 . 
         [0069]    A driving force of the drive mechanism  18  is transmitted to the movable shade  15  by a link member  35  that functions as a transmission mechanism. The link member  35  is formed of a metal material that is bent in a predetermined shape. The link member  35  includes an extension portion  36  that extends in an up-down direction, a first joint portion  37  that is bent from the upper end of the extension portion  36 , and a second joint portion  38  that is bent from the lower end of the extension portion  36 . 
         [0070]    The first joint portion  37  is joined to the connecting piece  16   b , so that the link member  35  is connected to the movable shade  15 . The second joint portion  38  is joined to the connecting groove  22   a  of the output shaft  22 , so that the link member  35  is connected to the drive mechanism  18 . Both the connecting piece  16   b  that is a connecting point of the first joint portion  37  and the connecting groove  22   a  of the output shaft  22  that is a connecting point of the second joint portion  38  are positioned on the left side of the optical axis P of the light source  11  (see  FIG. 5 ). 
         [0071]    As described above, the link member  35  is provided so as to exist at a position where the link member connects the connecting piece  16   b  to the connecting groove  22   a , so that the connecting point of the movable shade  15  and the connecting point of the output shaft  22  are at positions close to each other. Accordingly, it may be possible to improve the efficiency of the transmission of the driving force of the drive mechanism  18  to the movable shade  15 . 
         [0072]    Further, since the link member  35  is formed of a wiry metal material that is bent in a predetermined shape and the extension portion  36  of the link member  35  is formed so as to extend linearly, it may be possible to reduce the manufacturing costs of the link member  35  and to simplify the structure of the link member  35 . 
         [0073]    A connection terminal  39 , a first diode  40 , and a second diode  41  are disposed in the disposition case  33  that protrudes from the yoke  19  to the left side. 
         [0074]    The connection terminal  39  includes base portions  39   a ,  39   a , and  39   a  that are mounted in the disposition case  39 , and connection portions  39   b  and  39   b  that protrude rearward from the base portions  39   a  and  39   a.    
         [0075]    The first diode  40  is a diode that absorbs a counter electromotive force. The first diode  40  having a function, which reduces noise by absorbing magnetic energy discharged when the supply of current to the coil  21  is stopped, is disposed at a portion close to the coil  21  in the disposition case  33 , and is connected between the base portions  39   a  and  39   a.    
         [0076]    The second diode  41  is a diode that protects a circuit when being reversely connected. The second diode  41  is disposed on the left side of the first diode  40  and is connected between the base portions  39   a  and  39   a.    
         [0077]    In the vehicle headlight  1 , as described above, the first diode  40 , which absorbs magnetic energy discharged when the supply of current to the coil  21  is stopped, is disposed closer to the coil  21  than the second diode  41 . Accordingly, since a distance between the first diode  40  and the coil  21  is small, it may be possible to successfully exhibit a function of absorbing magnetic energy by the first diode  40 . 
         [0078]    Further, since the connection terminal  39 , the first diode  40 , and the second diode  41  are disposed in the disposition case  33 , it may be possible to reduce the size of the vehicle headlight by the integration of functions and the effective use of a disposition space. 
         [0079]    Furthermore, since the disposition case  33  is provided on the coil bobbin  20 , it is not necessary to form the disposition case  33  as a separate component and it may be possible to reduce the size of the vehicle headlight by the reduction of the number of components and the effective use of a disposition space. 
         [0080]    A connector case  42  is mounted on the rear end portion of the disposition case  33 . The connector case  42  includes a plate-like closing surface portion  43  and a cylindrical case portion  44  that are formed integrally with each other. The closing surface portion  43  closes the inner space  33   a  of the disposition case  33 . The case portion  44  protrudes rearward from the closing surface portion  43 . A terminal insertion hole  43   a  is formed at the closing surface portion  43  so as to pass through the closing surface portion in the front-rear direction. 
         [0081]    While the connector case  42  is mounted on the disposition case  33 , the connection portions  39   b  and  39   b  of the connection terminal  39  are inserted into the terminal insertion hole  43   a  from the front side. Accordingly, the connection portions  39   b  and  39   b  are positioned in the case portion  44 . 
         [0082]    The case portion  44  of the connector case  42  and the connection portions  39   b  and  39   b  of the connection terminal  39  are inserted into the insertion hole  12   c  formed at the stationary shade  12 , protrude to the rear side of the stationary shade  12 , and are positioned on the outside of the reflector  10  (see  FIG. 7 ). A plug, which is connected to a power circuit (not shown), is connected to the connection portions  39   b  and  39   b  of the connection terminal  39 . Accordingly, driving current is supplied to the coil  21  from the power circuit through the connection terminal  39 . 
         [0083]    Since the case portion  44  of the connector case  42 , in which the connection portions  39   b  and  39   b  of the connection terminal  39  are positioned as described above, is disposed on the outside of the reflector  10 , the influence of heat between the case portion  44  and the space in the reflector  10  is suppressed. 
         [0084]    In the vehicle headlight  1 , as described above, the rotation of the movable shade  15  is restricted by the stopper piece  12   d  formed at the stationary shade  12  pushed by the pushing force of the pushing spring while current is not supplied to the coil  21 . Accordingly, the movable shade  15  is held at the shielding position (see  FIG. 4 ). In this case, the length of a portion of the output shaft  22  of the drive mechanism  18 , which protrudes from the yoke  19 , is longest. 
         [0085]    When current is supplied to the coil  21  in the vehicle headlight  1 , the output shaft  22  is moved in the axial direction, the length of a portion of the output shaft protruding from the yoke  19  is reduced, and the driving force of the drive mechanism  18  is transmitted to the movable shade  15  through the link member  35 . Accordingly, the movable shade  15  is rotated about the supported shaft  16   a  as a fulcrum up to the non-shielding position against the pushing force of the pushing spring (see  FIG. 5 ). 
         [0086]    When the supply of current to the coil  21  is stopped, the movable shade  15  is rotated about the supported shaft  16   a  as a fulcrum up to the shielding position by the pushing force of the pushing spring (see  FIG. 4 ). 
         [0087]    A bar-like frame (not shown) where the lamp unit  7  is supported is disposed in the lamp chamber  5 , and the frame is tiltably supported by the lamp housing  2  through an aiming adjustment mechanism (not shown). Accordingly, the lamp unit  7  and the frame are integrally tilted in the up-down direction or the left-right direction by the operation of the aiming adjustment mechanism, so that the adjustment (initial adjustment) of the optical axis of the light source  11  is performed. 
         [0088]    Further, the lamp unit  7  may be supported by the frame so as to be tiltable, for example, in the up-down direction. If the lamp unit  7  is supported by the frame so as to be tiltable in the up-down direction, a leveling adjustment mechanism (not shown) is connected to the lamp unit  7  and the lamp unit  7  is tilted in the up-down direction by the operation of the leveling adjustment mechanism. Accordingly, the orientation of the optical axis of the light source  11  is adjusted according to the weight of materials loaded on a vehicle. 
         [0089]    The leveling adjustment mechanism includes a leveling actuator that is disposed below the stationary shade  12 . A connection portion, which protrudes downward, is formed at the lower end portion of the stationary shade  12 , and the connection portion is connected to the leveling actuator. Accordingly, a driving force of the leveling actuator is transmitted to the lamp unit  7  through the connection portion, so that the lamp unit  7  is tilted in the up-down direction. Therefore, the orientation of the optical axis of the light source  11  is adjusted according to the weight of materials loaded on a vehicle. 
         [0090]    When the leveling adjustment mechanism is to be provided in the vehicle headlight  1  as described above, it is preferable that the connection portion formed at the lower end portion of the stationary shade  12  be positioned near the barycenter of the lamp unit  7 . It may be possible to improve vibration resistance by positioning the connection portion near the barycenter of the lamp unit  7 . 
         [0091]    In addition, the lamp unit  7  may be supported by the frame so as to be rotatable, for example, in the horizontal direction. If the lamp unit  7  is supported by the frame so as to be rotatable in the horizontal direction, a swivel mechanism (not shown) is connected to the lamp unit  7  and the lamp unit  7  is rotated in the horizontal direction by the operation of the swivel mechanism. Accordingly, the orientation of the optical axis is changed so as to follow the traveling direction of a vehicle. 
         [0092]    Meanwhile, if a frame-shaped frame is disposed in the lamp chamber  5 , it is preferable that the case portion  44  of the connector case  42  and the connection portions  39   b  and  39   b  of the connection terminal  39  protrude rearward from the inside of the frame. If the case portion  44  and the connection portions  39   b  and  39   b  protrude rearward from the inside of the frame, a disposition space is effectively used for the case portion  44  and the connection portions  39   b  and  39   b . Accordingly, it may be possible to reduce the size of the vehicle headlight  1  by that much. 
         [0093]    Since at least a part of the yoke  19  of the drive mechanism  18  is formed integrally with the stationary shade  12  in the vehicle headlight  1  as described above, it may be possible to reduce the size of the vehicle headlight  1  and the number of components of the vehicle headlight  1 . In particular, since a mounting member, which is used to mount the yoke on the stationary shade and is disposed below the yoke, is unnecessary, the height of a beam switching structure, which includes the stationary shade  12  and the movable shade  15 , in the up-down direction is reduced by that much. Accordingly, it may be possible to reduce the size of the vehicle headlight  1  in the up-down direction. 
         [0094]    Further, since at least a part of the yoke  19  of the drive mechanism  18  is formed integrally with the stationary shade  12 , it may be possible to increase the strength of the yoke  19  and to reduce the weight of the yoke  19 . 
         [0095]    Furthermore, since the middle M of the yoke  19  in the left-right direction and the rotation center S of the movable shade  15  are positioned on the opposite sides of the optical axis P of the light source  11  in the left-right direction, it may be possible to make the barycenter of the lamp unit  7  be close to the middle of the stationary shade in the left-right direction and to improve vibration resistance. 
         [0096]    In addition, since the middle M of the yoke  19  is positioned on the left side of the optical axis P and the rotation center S of the movable shade  15  is positioned on the right side of the optical axis P, the drive mechanism  18  and the movable shade  15  are disposed so as to be balanced each other in the left-right direction. Accordingly, it may be possible to reduce the size of the vehicle headlight  1  by the effective use of a disposition space. 
         [0097]    Further, the yoke  19  includes the integrated yoke portion  23  and the separate yoke portion  24  joined to the integrated yoke portion  23 . Each of the integrated yoke portion  23  and the separate yoke portion  24  includes at least two surface portions (the lower surface portion  25 , the side surface portions  26  and  28 , the upper surface portion  27 , and the front surface portion  29 ). 
         [0098]    Accordingly, it may be possible to easily form the yoke  19  by joining the separate yoke portion  24  to the integrated yoke portion  23 . 
         [0099]    Furthermore, the closed magnetic path portion  30  is formed in the yoke, one side surface portion  26  and the lower surface portion  25  of the closed magnetic path portion  30  are formed at the integrated yoke portion  23 , and the other side surface portion  28  and the upper surface portion  27  of the closed magnetic path portion  30  are formed at the separate yoke portion  24 . 
         [0100]    Accordingly, it may be possible to increase the driving force of the drive mechanism  18  by the closed magnetic path portion  30  and to easily form the closed magnetic path portion  30  by joining the separate yoke portion  24  to the integrated yoke portion  23 . 
         [0101]    Moreover, since the front surface portion  29  is formed at the integrated yoke portion  23  or the separate yoke portion  24 , not only the closed magnetic path portion  30  but also the front surface portion  29  contributes to the increase of the driving force of the drive mechanism  18  and the inner structure of the yoke  19  is not seen from the outside of the cover  3 . Accordingly, it may be possible to improve the appearance of the yoke. 
         [0102]    Meanwhile, an example where the yoke  19  is positioned on the front side of the stationary shade  12  has been described above. However, conversely, the yoke  19  may be positioned on the rear side of the stationary shade  12 . Meanwhile, since the light source  11  is positioned on the rear side of the stationary shade  12 , the yoke  19  does not easily interfere with the path of light emitted from the light source  11  if the yoke  19  is positioned on the front side of the stationary shade  12 . Accordingly, it may be possible to position the yoke  19  on the upper side. This contributes to the reduction of the size of the vehicle headlight  1 . 
         [0103]    Further, the lower surface portion  25 , the side surface portions  26  and  28 , the upper surface portion  27 , and the front surface portion  29 , which are five surface portions forming the yoke  19 , may be formed as the surface portions of any one of the integrated yoke portion  23  and the separate yoke portion  24 . Furthermore, the number of the surface portions of the integrated yoke portion  23  and the separate yoke portion  24  are also arbitrary. 
         [0104]    The shape and structure of each portion, which have been described in the above-mentioned preferred embodiment of the invention, are merely examples of the embodiment of the invention, and the technical scope of the invention should not be limited to the shape and structure of each portion. 
         [0105]    While aspects of embodiments of the present invention have been shown and described above, other implementations are within the scope of the claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.