JP2006040786A - Vehicular headlamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light distribution pattern for a high beam with excellent distant visibility without adversely influencing a light distribution pattern for a low beam, in a projector type vehicular headlamp having a movable shade. <P>SOLUTION: This vehicular headlamp is so structured that a bulb support base 34 for supporting a light source bulb 22 and the movable shade 32 can be moved between first and second movement positions by a driving device 36. At the first movement position, the light distribution pattern for a low beam can be obtained by setting the light source 22a at a first light source position located on an optical axis Ax and by setting the movable shade 32 at a first shade position where its upper edge 32a is located on the optical axis Ax at the rear-side focal point F of a projection lens 28. At the second movement position, the light distribution pattern for a high beam having a small diffusion angle as a whole, high central luminosity and excellent distant visibility can be obtained by setting the light source 22a at the second light source position in front of the first light source position in front of the first light source position and by setting the movable shade 32 at a second shade position below the first shade position. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a so-called projector-type vehicle headlamp, and particularly to a vehicle headlamp provided with a movable shade.

  In general, a projector-type vehicle headlamp has a projection lens disposed on an optical axis extending in the longitudinal direction of the vehicle, and a light source disposed behind the rear focal point. The reflector is configured to reflect near the optical axis. When a low beam light distribution pattern is formed by the projector-type vehicle headlamp, the reflector is provided with a shade arranged so that the upper edge is positioned near the optical axis near the rear focal point of the projection lens. A part of the reflected light from the light is shielded, and a predetermined cut-off line is formed at the upper end of the low beam light distribution pattern.

  In this case, in “Patent Document 1”, as the shade, the first shade position where the upper end edge is located near the optical axis in the vicinity of the rear focal point, and the position of the upper end edge are the positions at the first shade position. A projector-type vehicular headlamp having a movable shade configured to be movable between a second shade position located below the position is described.

  Further, in “Patent Document 2”, in the projector-type vehicle headlamp provided with the shade, the light source is arranged with respect to a first light source position located near the optical axis, and the first light source position. A device including a light source driving device that moves between a second light source position located on the left side, the right side, or the lower side is described.

JP 2002-56708 A JP 2002-42516 A

  In the vehicle headlamp described in the “Patent Document 1”, a high beam light distribution pattern can be formed by moving the movable shade to the second shade position. It can be used for both low beam and high beam.

  However, in the vehicle headlamp described in “Patent Document 1”, the low beam distribution pattern and the high beam distribution pattern are formed by the reflected light from the same reflection region of the reflector. If the shape of the reflective surface is suitable for the low-beam light distribution pattern, it is not always possible to obtain a suitable light distribution pattern for the high-beam light distribution pattern. Then, there is a problem that an appropriate light distribution pattern cannot always be obtained as the low beam light distribution pattern.

  On the other hand, if a lamp configuration including a movable light source as described in “Patent Document 2” is employed, the light intensity distribution of the low beam light distribution pattern can be changed by moving the light source. It becomes possible.

  However, the vehicle headlamp described in “Patent Document 2” has a problem that a high-beam light distribution pattern cannot be obtained because the shade is fixed. Further, as described in “Patent Document 2”, the light intensity distribution of the low beam light distribution pattern can be changed only by moving the light source in the direction orthogonal to the optical axis. There is a problem that it cannot be changed.

  The above problem is not only when switching between the light distribution pattern for the low beam and the light distribution pattern for the high beam, but also the light distribution pattern for the low beam and the intermediate light distribution pattern (that is, the light distribution pattern for the low beam and the light distribution pattern for the high beam). In the case of switching to an intermediate light distribution pattern between (1) and (2), the same problem may occur.

  The present invention has been made in view of such circumstances, and in a projector-type vehicle headlamp equipped with a movable shade, a high-beam light distribution pattern without adversely affecting the low-beam light distribution pattern. Alternatively, it is an object of the present invention to provide a vehicular headlamp that can make an intermediate light distribution pattern a light distribution pattern with excellent distance visibility.

  According to the present invention, not only the shade but also the light source is movable, and these can be moved integrally, and the above object is achieved by devising the moving direction of the light source.

That is, the vehicle headlamp according to the present invention is
A projection lens disposed on the optical axis extending in the vehicle front-rear direction, a light source disposed rearward of the rear focal point of the projection lens, and light from this light source is reflected toward the optical axis toward the front. In a vehicle headlamp comprising: a reflector to be operated; and a movable shade configured to be able to shield part of the reflected light from the reflector;
The light source is configured to be movable between a first light source position located in the vicinity of the optical axis and a second light source position located in front of the first light source position;
The movable shade includes a first shade position where an upper end edge of the movable shade is located near the optical axis in the vicinity of the rear focal point, and a position of the upper end edge is lower than a position at the first shade position. Configured to be movable between a second shade position located;
The light source and the movable shade are supported by a common support member,
The supporting member is driven by a predetermined driving device so that the light source is at the first light source position and the movable shade is at the first shade position, and the light source is the second light source. And the movable shade is configured to be movable between a second movement position at the second shade position.

  The type of the “light source” is not particularly limited, and for example, a discharge light emitting part of a discharge bulb, a filament of a halogen bulb, or the like can be employed.

  As long as the “second light source position” is located in front of the first light source position, the specific position is not particularly limited. It is preferable to set the position about 3 mm forward, and it is more preferable to set the position about 1.5 to 2.5 mm forward with respect to the first light source position.

  As long as the “reflector” is configured to reflect light from the light source forward and toward the optical axis, the specific configuration such as the size and the shape of the reflecting surface is not particularly limited. Absent.

  The specific configuration such as the shape and size of the “movable shade” is not particularly limited. In addition, the “movable shade” is configured to shield a part of the reflected light from the reflector. At that time, the movable shade shields a part of the reflected light when in the first shade position. If it is configured, when it is in the second shade position, it may be configured to completely cancel the shielding of the reflected light, or may be configured to partially cancel the shielding of the reflected light. May be.

  The specific position of the “second shade position” is not particularly limited as long as it is located below the first shade position, but from the viewpoint of effectively releasing the shielding. The downward displacement amount is preferably set to 3 mm or more, and the downward displacement amount is more preferably set to 3.5 mm or more.

  The above-mentioned “driving device” is not particularly limited as long as the supporting member that supports the light source and the movable shade can be moved between the first and second moving positions. For example, a solenoid or a pulse motor can be used. Further, the movement mode of the support member by the driving of the “driving device” is not particularly limited, and for example, those by a rotational motion or a linear reciprocating motion can be adopted.

  As shown in the above configuration, the vehicular headlamp according to the present invention is configured as a projector-type vehicular headlamp having a movable shade, and the light source and the movable shade are supported by a common support member. Since the support member is configured to be movable between the first and second movement positions by the driving device, the following operational effects can be obtained.

  That is, at the first movement position, the light source is at the first light source position located in the vicinity of the optical axis, and the movable shade has the upper end edge located near the optical axis near the rear focal point of the projection lens. Since it is in the shade position, a part of the reflected light from the reflector is shielded by the movable shade, thereby obtaining a low beam light distribution pattern having a cut-off line as an inverted image of the upper edge of the movable shade at the upper end. be able to.

  On the other hand, in the second movement position, the light source is located at the second light source position positioned in front of the first light source position, and the position of the upper edge of the movable shade is lower than the position at the first shade position. Therefore, a high beam light distribution pattern or an intermediate light distribution pattern can be formed.

  The intermediate light distribution pattern can be formed by setting the second shade position closer to the first shade position than when forming the high beam light distribution pattern. If the second shade position is set to a position relatively close to the first shade position, this intermediate light distribution pattern is cut off as if the cut-off line of the low beam light distribution pattern was translated upward. It can be set as the light distribution pattern which has.

  Then, by moving the light source from the first light source position to the second light source position, it is possible to increase the degree of concentration of the reflected light from the reflector on the rear focal plane of the projection lens, and the movable shade By moving from the first shade position to the second shade position, it is possible to irradiate light above the cut-off line position of the low beam light distribution pattern. As a result, the light distribution pattern for the high beam or the intermediate light distribution pattern is made into a light distribution pattern that has a small diffusion angle and a high central luminous intensity and excellent distance visibility compared to the light distribution pattern for the low beam. Can do.

  As described above, according to the present invention, in the projector-type vehicle headlamp provided with the movable shade, the high-beam light distribution pattern or the intermediate light distribution pattern is visually recognized in the distance without adversely affecting the low-beam light distribution pattern. A light distribution pattern with excellent properties can be obtained.

  Moreover, in the present invention, since the above-described effects can be obtained at a single drive position, the lamp can be reduced in weight and size as compared with the case where a plurality of drive positions are used, In addition, the cost of the lamp can be reduced.

  Furthermore, in the present invention, since the movement of the light source and the movement of the movable shade are performed completely in synchronism, the above-described effects can be obtained so as not to give a sense of incongruity to the own vehicle driver.

  As described above, the shape of the reflecting surface of the “reflector” is not particularly limited in the above configuration. However, the reflecting surface of the reflector is projected at a point near the first light source position as the first focal point and near the optical axis. If the configuration has a substantially elliptical vertical cross-sectional shape in which the second focal point is a point located in front of the rear focal point of the lens, the following operational effects can be obtained.

  That is, the vertical cross-sectional shape of the reflecting surface of the reflector is set to be substantially elliptical, and the second focal point is set in front of the rear focal point of the projection lens, whereby the second focal point is set to the rear focal point of the projection lens. As compared with the case where the position is set to, the degree of condensing of the reflected light from the reflector on the rear focal plane of the projection lens can be relaxed. It can be a light pattern. On the other hand, when the light source moves forward from the first focal point, the convergence position of the reflected light from the reflector moves from the second focal point to the rear side thereof, so that the second focal point is located forward of the rear focal point of the projection lens. By setting, it is possible to effectively increase the degree of condensing of the reflected light from the reflector on the rear focal plane of the projection lens when the light source moves to the second light source position. As a result, a high beam light distribution pattern or an intermediate light distribution pattern with a small diffusion angle and a high central luminous intensity can be obtained with certainty.

  In the above configuration, a fixed shade that shields part of the reflected light from the reflector is provided in the vicinity of the rear focal point of the projection lens, and the height position of the upper edge of the fixed shade is at the first shade position. If the height position is set between the upper edge of the movable shade at that time and the upper edge of the movable shade at the second shade position, the following operational effects can be obtained.

  That is, when trying to obtain a light distribution pattern having a cut-off line at the upper edge as an intermediate light distribution pattern, the amount of movement of the movable shade between the first and second shade positions is set to a relatively small value. There is a need to. However, since this movable shade is supported by a common support member together with the light source, if the first and second light source positions are set to preferred positions, the second shade position may be the first shade depending on the configuration of the support member. It will be far away from the position. Therefore, if a fixed shade is provided in the vicinity of the rear focal point, and the position of the upper end edge is set to a position suitable for the cut-off line formation of the intermediate light distribution pattern, the second shade position can be set arbitrarily to some extent. As a result, the degree of freedom in lamp design can be increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a side sectional view showing a vehicle headlamp 10 according to an embodiment of the present invention.

  As shown in the figure, this vehicle headlamp 10 is a light extending in the vehicle front-rear direction in a lamp chamber formed by a lamp body 12 and a transparent light-transmitting cover 14 attached to the front end opening. A lamp unit 20 having an axis Ax is accommodated via an aiming mechanism 50 so as to be tiltable in the vertical direction and the horizontal direction.

  In the vehicular headlamp 10, when the aiming adjustment by the aiming mechanism 50 is completed, the optical axis Ax of the lamp unit 20 is a downward direction of about 0.5 to 0.6 ° with respect to the vehicle longitudinal direction. It is designed to extend.

  FIG. 2 is a side sectional view showing the lamp unit 20 as a single item, and FIG. 3 is a detailed view of the main part of FIG.

  As shown in these drawings, the lamp unit 20 is a projector-type lamp unit, and includes a light source bulb 22, a reflector 24, a holder 26, a projection lens 28, a movable shade 32, and a bulb support base. 34 and a drive device 36 are provided.

  The projection lens 28 is a plano-convex lens having a convex front surface and a flat rear surface, and is disposed on the optical axis Ax. The projection lens 28 projects the image on the rear focal plane including the rear focal point F forward as a reverse image.

  The light source bulb 22 is a discharge bulb such as a metal halide bulb having a discharge light emitting portion as a light source 22a, and is inserted into a bulb insertion portion 34a of a bulb support base 34 disposed in the vicinity of the rear top opening 24b of the reflector 24. While being worn and fixed by the wire spring 30, it is inserted into the rear top opening 24b of the reflector 24 from the rear side. The light source 22a of the light source bulb 22 is disposed on the rear side of the rear focal point F of the projection lens 28. When the light source 22a is at a first light source position to be described later, the optical axis Ax is along the optical axis Ax. It is arranged to extend.

  The reflector 24 is configured to reflect the light from the light source 22a forward and toward the optical axis Ax. The reflecting surface 24a of the reflector 24 has a cross-sectional shape including the optical axis Ax set to an elliptical shape with the center of the light source 22a on the optical axis Ax as the first focal point F1, and the eccentricity is horizontal from the vertical cross section. It is set to gradually increase toward the cross section. At this time, the second focal point F2 of the ellipse that forms a vertical section including the optical axis Ax is set to a point that is located slightly in front of the rear focal point F of the projection lens 28. As a result, the reflector 24 substantially converges the light from the light source 22a reflected by the reflecting surface 24a to the second focal point F2 in the vertical cross section, and moves the converging position considerably forward in the horizontal cross section. It is designed to move.

  The holder 26 is formed so as to extend in a substantially cylindrical shape from the opening at the front end of the reflector 24 toward the front, and the reflector 24 is fixedly supported at the rear end, and the projection lens 28 is fixedly supported at the front end. ing. The holder 26 has a lower region cut out, and a plurality of aiming brackets 26 a for connecting the lamp unit 20 to the aiming mechanism 50 are formed at the peripheral edge of the rear end.

  The movable shade 32 is provided so as to be positioned in a substantially lower half portion in the internal space of the holder 26. The movable shade 32 is formed with a pair of left and right stays 32b extending rearward at the lower end thereof, and is fixedly supported by the valve support base 34 at the rear ends of both stays 32b. The movable shade 32 is rotatably supported by the reflector 24 together with the valve support base 34 via a rotation pin 44 extending in the left-right direction in the vicinity of the rear end portions of both stays 32b. The rotation pin 44 is disposed at a position about 10 to 30 ° behind the light source 22a vertically below, and is formed on a pair of left and right tabs 24h formed near the rear of the device mounting portion 24d in the reflector 24. It is inserted and supported so that it can rotate.

  The movable shade 32 is a first shade position indicated by a solid line in FIGS. 2 and 3 and a second shade indicated by a two-dot chain line in FIGS. 2 and 3 rotated by a predetermined angle downward from the first shade position. The position can be taken.

  The upper end edge 32a of the movable shade 32 is formed in a step difference on the left and right, and extends in a substantially arc shape in the horizontal direction. When the movable shade 32 is in the first shade position, the upper edge 32a is disposed so as to pass through the rear focal point F of the projection lens 28 and extend along the rear focal plane. When moved to the second shade position, it is arranged obliquely forward and lower than when it is in the first shade position. And in this 2nd shade position, the upper end edge 32a of the movable shade 32 is located about 4 mm below from the time of being in a 1st shade position.

  A fixed shade 40 for preventing stray light reflected by the reflector 24 from entering the projection lens 28 is integrally formed with the holder 26 in front of the movable shade 32.

  The light source 22a has a first light source position whose center is located at the first focus F1 and a second center whose center is located at a point A slightly below the first focus F1 by the rotation of the bulb support base 34. The light source position can be taken. The specific position of this point A is set to a position approximately 2 mm forward and approximately 0.5 mm below the first focal point F1.

  When the light source 22a is at the first light source position, the center thereof is located at the first focal point F1, so that the light from the center of the light source 22a reflected by the reflector 24 is indicated by a solid line in FIGS. Furthermore, it intersects the optical axis Ax at the second focal point F2 of the ellipse. On the other hand, when the light source 22a is at the second light source position, the center of the light source 22a is located at a point A slightly in front of the first focal point F1, so that the light from the center of the light source 22a reflected by the reflector 24 is 2 and 3, it intersects with the optical axis Ax on the rear side of the second focal point F2, as indicated by a two-dot chain line.

  At this time, since the second focal point F2 is located in front of the rear focal point F of the projection lens 28, the degree of condensing of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 is determined by the light source 22a. Is higher at the second light source position than at the first light source position. In addition, since the second light source position is not only located in front of the first light source position but also slightly lower, the condensing position on the rear focal plane of the projection lens 28. Is slightly displaced with respect to the optical axis Ax.

  The drive device 36 is composed of a solenoid having a plunger 36 a extending rearward, and is fixed to a device attachment portion 24 d formed on the lower surface of the bottom wall 24 c of the reflector 24. The plunger 36a of the driving device 36 is engaged with the lower end portion of the valve support base 34 at the tip portion thereof, thereby transmitting the reciprocating motion of the plunger 36a in the front-rear direction as the rotational motion of the valve support base 34. It is like that.

  The drive device 36 is driven when a beam changeover switch (not shown) is operated, and moves the plunger 36a in the front-rear direction, whereby the bulb support base 34 is moved to the light source 22a. Is located at the first light source position and the movable shade 32 is at the first shade position, and the light source 22a is at the second light source position and the movable shade 32 is at the second shade. It is made to move between the second movement positions at the positions.

  At this time, when the valve support base 34 moves to the first movement position, the upper end edges of both stays 32b of the movable shade 32 come into contact with the lower end surface 26b of the notch portion of the holder 26 at the front end portion thereof. Is positioned at the first shade position and the light source 22a is positioned at the first light source position. On the other hand, when the valve support base 34 is moved to the second movement position, the valve support base 34 is opened at the rear top opening of the reflector 24. The movable shade 32 is positioned at the second shade position and the light source 22a is positioned at the second light source position by contacting the positioning contact portion 24g formed on the upper portion of the portion 24b.

  4 is a diagram showing an optical path when the valve support base 34 is in the first movement position, and FIG. 5 is a diagram showing an optical path when the valve support base 34 is in the second movement position.

  As shown in FIG. 4, when the valve support base 34 is in the first movement position, the movable shade 32 is in the first shade position, so that part of the reflected light from the reflector 24 is shielded by the movable shade 32. The remainder enters the projection lens 28.

  On the other hand, as shown in FIG. 5, when the valve support base 34 is in the second movement position, the movable shade 32 is in the second shade position, so that almost all of the reflected light from the reflector 24 is movable shade. The light enters the projection lens 28 without being shielded by 32. At this time, since the light source 22a is at the second light source position, the degree of condensing of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 is such that the light source 22a is at the first light source position. It is higher than when.

  FIG. 6 is a perspective view showing a light distribution pattern formed on a virtual vertical screen arranged at a position 25 m ahead of the lamp by light irradiated forward from the vehicle headlamp 10.

  A light distribution pattern PL shown in FIG. 6A is a low beam light distribution pattern formed when the valve support base 34 is in the first movement position, and a light distribution pattern PH shown in FIG. This is a high-beam light distribution pattern formed when the valve support base 34 is in the second movement position.

  As shown in FIG. 6A, the low beam light distribution pattern PL is a left light distribution light beam distribution pattern, and has upper and lower cut-off lines CL1 and CL2 at its upper edge. The cut-off lines CL1 and CL2 extend in the horizontal direction at the left and right steps with the VV line passing through the HV, which is a vanishing point in the front direction of the lamp, in the vertical direction, and are on the right side of the VV line. The opposite lane side portion is formed as a lower cut-off line CL1, and the own lane side portion on the left side of the VV line is formed as an upper cut-off line CL2 that rises from the lower cut-off line CL1 through an inclined portion. Is formed. In this low beam distribution pattern PL, the position of the elbow point E, which is the intersection of the lower cut-off line CL1 and the VV line, is set to a position about 0.5 to 0.6 ° below HV. A hot zone HZL, which is a high luminous intensity region, is formed so as to surround the elbow point E slightly to the left.

  This low beam light distribution pattern PL is obtained by converting the image of the light source 22 a formed on the rear focal plane of the projection lens 28 by the light from the light source 22 a reflected by the reflection surface 24 a of the reflector 24, using the projection lens 28. It is formed by projecting as a reverse projection image on the screen, and the cut-off lines CL1 and CL2 are formed as a reverse projection image of the upper edge 32a of the movable shade 32.

  On the other hand, as shown in FIG. 5B, the high beam light distribution pattern PH has a shape obtained by expanding the low beam light distribution pattern PL to the region above the cut-off lines CL1 and CL2. A hot zone HZH is formed around V. This is because the shielding of the reflected light from the reflector 24 by the movable shade 32 is released by the movement of the movable shade 32 from the first shade position to the second shade position.

  At this time, the high beam light distribution pattern PH has a slightly smaller overall diffusion angle than the low beam light distribution pattern PL, and its hot zone HZH is higher than the hot zone HZL of the low beam light distribution pattern PL. Is also quite bright. This is because the concentration of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 is higher when the light source 22a is at the second light source position than when the light source 22a is at the first light source position. It is due to what has become.

  As described above in detail, the vehicular headlamp 10 according to the present embodiment is configured as a projector-type lamp unit in which the lamp unit 20 includes the movable shade 32. However, the light source bulb 22 and the movable shade are provided. 32 is supported by a valve support base 34 which is a common support member, and this valve support base 34 is configured to be movable between the first and second movement positions by the drive device 36. Such effects can be obtained.

  That is, the lamp unit 20 according to the present embodiment can selectively form the low beam light distribution pattern PL and the high beam light distribution pattern PH, although the light source 22a is single.

  At this time, in the first movement position, the light source 22a is at the first light source position located on the optical axis Ax, and the movable shade 32 has the upper edge 32a at the rear focal point F of the projection lens 28 at the optical axis Ax. Since it is in the first shade position located above, a part of the reflected light from the reflector 24 is shielded by the movable shade 32, and thereby the cut-off line CL1 as an inverted image of the upper edge 32a of the movable shade 32. , And a low beam light distribution pattern PL having CL2 at the upper end.

  On the other hand, in the second movement position, the light source 22a is located at the second light source position located in front of the first light source position, and the position of the upper edge 32a of the movable shade 32 is the position at the first shade position. Therefore, the high beam light distribution pattern PH can be obtained.

  At this time, the light source 22a moves from the first light source position to the second light source position, so that the degree of condensing of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 can be increased. By moving the movable shade 32 from the first shade position to the second shade position, it is possible to perform light irradiation above the positions of the cut-off lines CL1 and CL2. As a result, the high-beam light distribution pattern PH can be a light distribution pattern that has a small diffusion angle and a high central luminous intensity and excellent far-field visibility as compared with the low-beam light distribution pattern PL.

  As described above, according to the present embodiment, in the projector-type vehicle headlamp 10 including the movable shade 32, the high-beam light distribution pattern PH can be viewed in the distance without adversely affecting the low-beam light distribution pattern PL. It is possible to obtain an excellent light distribution pattern.

  In addition, in the present embodiment, since the above-described effects can be obtained at a single drive position 36, the lamp can be reduced in weight and size as compared with the case where a plurality of drive positions are used. It is possible to reduce the cost of the lamp.

  Furthermore, in the present embodiment, the movement of the light source 22a and the movement of the movable shade 32 are performed in complete synchronization, so that the above-described effects can be obtained without causing any discomfort to the driver of the vehicle. .

  At that time, in the vehicle headlamp 10 according to the present embodiment, the reflecting surface 24a of the reflector 24 has the first light source position as the first focus F1 and is ahead of the rear focus F on the optical axis Ax. Since it has an elliptical vertical cross-sectional shape with the second focal point F2 as the point located at, the following operational effects can be obtained.

  That is, the vertical cross-sectional shape of the reflecting surface 24a of the reflector 24 is set to be elliptical, and the second focal point F2 is set in front of the rear focal point F of the projection lens 28, thereby projecting the second focal point F2. Compared with the case where the position is set to the rear focal point F of the lens 28, the degree of condensing of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 can be relaxed, and thereby the light distribution for the low beam. The pattern PL can be a light distribution pattern having a somewhat large diffusion angle. On the other hand, when the light source 22a moves forward from the first focal point F1, the convergence position of the reflected light from the reflector 24 moves from the second focal point F2 to the rear side thereof, so that the second focal point F2 is moved to the rear side of the projection lens 28. By setting the position in front of the focal point F, the degree of concentration of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 when the light source 22a moves to the second light source position is effective. Can be enhanced. As a result, it is possible to reliably obtain a high beam light distribution pattern PH having a small diffusion angle and a high central luminous intensity as compared with the low beam light distribution pattern PL.

  Next, a modification of the above embodiment will be described.

  FIG. 7 is a view similar to FIG. 2 showing the lamp unit 120 according to this modification. As shown in the figure, the lamp unit 120 has the same basic configuration as that of the lamp unit 20 according to the above embodiment, but a fixed shade 138 is provided in the vicinity of the rear focal point F of the projection lens 28. The lamp unit 20 is different from the lamp unit 20 according to the above embodiment.

  The fixed shade 138 is formed of a belt-like plate extending in a substantially arc shape in the horizontal direction so as to be close to the rear surface of the movable shade 32, and is fixedly supported by the holder 26 at both ends thereof. The upper end edge 138a of the fixed shade 138 is formed in the left and right steps similarly to the upper end edge 32a of the movable shade 32, and the height position thereof is the upper end edge 32a of the movable shade 32 when it is at the first shade position. And the height position between the upper end edge 32a of the movable shade 32 when it is in the second shade position. Specifically, the upper end edge 138a of the fixed shade 138 is set to be positioned about 0.3 to 0.4 mm below the upper end edge 32a of the movable shade 32 when in the first shade position.

  FIG. 8 is a diagram showing an optical path when the valve support base 34 is in the first movement position, and FIG. 9 is a diagram showing an optical path when the valve support base 34 is in the second movement position.

  As shown in FIG. 8, when the valve support base 34 is in the first movement position, the movable shade 32 is in the first shade position, so that part of the reflected light from the reflector 24 is caused by the movable shade 32. The remaining light enters the projection lens 28. At this time, the fixed shade 138 is close to the rear surface of the movable shade 32, and the upper end edge 138a thereof is positioned slightly below the upper end edge 32a of the movable shade 32, so that it is shielded by the fixed shade 138. All the reflected light from the reflector 24 is also shielded by the movable shade 32. Accordingly, at this time, the fixed shade 138 has no particular optical meaning.

  On the other hand, as shown in FIG. 9, when the valve support base 34 moves to the second movement position, the movable shade 32 moves to the second shade position, but the fixed shade 138 is at the original position. A part of the reflected light from is blocked by the fixed shade 138, and the rest is incident on the projection lens 28. At this time, since the light source 22a has moved to the second light source position, the degree of condensing of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 is high.

  FIG. 10 is a perspective view of a light distribution pattern formed on a virtual vertical screen disposed at a position 25 m ahead of the lamp by light irradiated forward from a vehicle headlamp including the lamp unit 120 according to the present modification. FIG.

  A light distribution pattern PL shown in FIG. 6A is a low beam light distribution pattern formed when the valve support base 34 is in the first movement position, and a light distribution pattern PM shown in FIG. , An intermediate light distribution pattern formed when the valve support base 34 is in the second movement position.

  As shown in FIG. 5A, the low beam light distribution pattern PL is exactly the same as that in the above embodiment.

  On the other hand, the intermediate light distribution pattern PM is an intermediate light distribution pattern between the low beam light distribution pattern PL and the high beam light distribution pattern PH, as shown in FIG. Although the shape is similar to that of the light pattern PL, the cut-off lines CL3 and CL4 are positioned about 0.3 to 0.4 ° above the cut-off lines CL1 and CL2 of the low-beam light distribution pattern PL.

  This is because the shielding of the reflected light from the reflector 24 by the movable shade 32 is released by the movement of the movable shade 32 from the first shade position to the second shade position, but the shielding by the fixed shade 138 still remains. The cut-off lines CL3 and CL4 are formed as reverse projection images of the upper edge 138a.

  The intermediate light distribution pattern PM has a slightly smaller overall diffusion angle than the low beam light distribution pattern PL, and its hot zone HZM is smaller than the hot zone HZL of the low beam light distribution pattern PL. It is quite bright. This is because the concentration of the reflected light from the reflector 24 on the rear focal plane of the projection lens 28 is higher when the light source 22a is at the second light source position than when the light source 22a is at the first light source position. It is due to what has become.

  By adopting the configuration of this modification, the following operational effects can be obtained.

  That is, the lamp unit 120 according to the present modification can selectively form the low beam light distribution pattern PL and the intermediate light distribution pattern PM, although the light source 22a is single.

  At that time, since the intermediate light distribution pattern PM has its hot zone HZM expanded upward with respect to the hot zone HZL of the low beam light distribution pattern PL, the visibility of the long-distance area on the road surface ahead of the vehicle is improved. However, in this intermediate light distribution pattern PM, the shielding by the movable shade 32 is not completely canceled, but the cutoff line CL3 displaced upward with respect to the cutoff lines CL1 and CL2 by the fixed shade 138. , CL4 is left, so that it is possible not to give a large glare to an oncoming vehicle driver or the like.

  Further, when the intermediate light distribution pattern PM having the cut-off lines CL3 and CL4 at the upper end edge is obtained only by the movable shade 32, the movement amount between the first and second shade positions is set as follows. Although the movable shade 32 needs to be set to a relatively small value, the movable shade 32 is supported by the bulb support base 34 together with the light source bulb 22. Therefore, if the first and second light source positions are set to preferred positions, the second shade is set. The position will be far away from the first shade position. In that respect, the lamp unit 120 according to this modification is provided with a fixed shade 138 in the vicinity of the rear focal point F of the projection lens 28, and the upper end edge 138a is located at the cut-off line CL3 of the intermediate light distribution pattern PM. Since the position is suitable for the formation of CL4, the second shade position can be arbitrarily set to some extent, thereby increasing the degree of freedom in designing the lamp.

  In the above-described embodiment and its modifications, the lamp units 20 and 120 are configured to form a low-beam light distribution pattern for left light distribution as the low-beam light distribution pattern PL. Even in the case where the light distribution pattern for low beam is formed, it is possible to obtain the same operational effects by adopting the same configuration as that of the above-described embodiment and its modification.

Side sectional view which shows the vehicle headlamp which concerns on one Embodiment of this invention Side sectional view which shows the lamp unit of the vehicle headlamp as a single item Detailed view of the main part of FIG. Side sectional view showing an optical path when the valve support base is in the first movement position in the embodiment. Side sectional view showing an optical path when the valve support base is in the second movement position in the embodiment. The figure which shows transparently the light distribution pattern formed on the virtual vertical screen arrange | positioned in the position of the lamp front 25m with the light irradiated ahead from the said vehicle headlamp The figure similar to FIG. 2 which shows the lamp unit which concerns on the modification of the said embodiment. Side sectional view showing an optical path when the valve support base is in the first movement position in the above modification. Side sectional view showing an optical path when the valve support base is in the second movement position in the above modification. The figure which shows in perspective the light distribution pattern formed on the said virtual vertical screen by the light irradiated ahead from the vehicle headlamp provided with the lamp unit which concerns on the said modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle headlamp 12 Lamp body 14 Translucent cover 20, 120 Lamp unit 22 Light source bulb 22a Light source 24 Reflector 24a Reflective surface 24b Rear top opening 24c Bottom wall 24d Device mounting part 24e Bracket 24g Positioning contact part 24h Tab 26 Holder 26a Aiming bracket 26b Notch lower end surface 28 Projection lens 30 Wire spring 32 Movable shade 32a, 138a Upper end edge 32b Stay 34 Valve support base 34a Valve insertion part 36 Drive device 36a Plunger 40, 138 Fixed shade 44 Rotating pin 50 Aiming mechanism A point Ax Optical axis CL1, CL3 Lower cut-off line CL2, CL4 Upper cut-off line E Elbow point F Rear focus F1 First focus F2 Second focus HZH, HZL, HZM Emissions PH high-beam light distribution pattern PL low-beam light distribution pattern PM intermediate light distribution pattern

Claims (3)

A projection lens disposed on the optical axis extending in the vehicle front-rear direction, a light source disposed rearward of the rear focal point of the projection lens, and light from this light source is reflected toward the optical axis toward the front. In a vehicle headlamp comprising: a reflector to be operated; and a movable shade configured to be able to shield part of the reflected light from the reflector;
The light source is configured to be movable between a first light source position located in the vicinity of the optical axis and a second light source position located in front of the first light source position;
The movable shade includes a first shade position where an upper end edge of the movable shade is located near the optical axis in the vicinity of the rear focal point, and a position of the upper end edge is lower than a position at the first shade position. Configured to be movable between a second shade position located;
The light source and the movable shade are supported by a common support member,
The supporting member is driven by a predetermined driving device so that the light source is at the first light source position and the movable shade is at the first shade position, and the light source is the second light source. A vehicular headlamp characterized by being configured to move between a movable position of the movable shade and a second moving position of the second shade position.   A substantially elliptical vertical shape in which the reflecting surface of the reflector has a point near the first light source position as a first focal point and a point located in front of the rear focal point near the optical axis as a second focal point. The vehicle headlamp according to claim 1, wherein the vehicle headlamp has a cross-sectional shape. In the vicinity of the rear focal point, a fixed shade that shields part of the reflected light from the reflector is provided,
The height position of the upper edge of the fixed shade is between the upper edge of the movable shade when it is at the first shade position and the upper edge of the movable shade when it is at the second shade position. The vehicle headlamp according to claim 1, wherein the vehicle headlamp is set at a height position.

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