JP2011181233A - Headlight for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a headlight for a vehicle excellent in a fail-safe function capable of irradiating low beams even if a driving member of a shade member is in trouble. <P>SOLUTION: The headlight for the vehicle 1, provided with a projection lens 8, a light source 10, a reflector 13, and a rotatable cylindrical shade member 20, is so structured to be provided with a biasing member 50 biasing the shade member 20 at all times toward a low-beam light distribution pattern position where a low-beam light distribution pattern forming part 20C is positioned in the vicinity of a rear focus of the projection lens 8, a first stopper 60A for positioning the shade member at a first light distribution pattern position rotated in one direction from the low-beam light distribution pattern position, a second stopper 60B for positioning the shade member at a second light distribution pattern position rotated in the other direction from the low-beam light distribution pattern position, and a driving member 30 for rotating the shade member 20 toward the first light distribution pattern position or a second light distribution pattern position against biasing force of the biasing member 50. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle headlamp, and more particularly to a projector-type vehicle headlamp having a variable light distribution function capable of changing a light distribution of a vehicle headlamp.

  2. Description of the Related Art Conventionally, vehicle headlamps that emit light toward the front of a vehicle using a projector-type lamp unit are known. As this vehicle headlamp, for example, Patent Document 1 includes a rotating shaft member (shade member) for forming a low beam light distribution pattern and a high beam light distribution pattern using one light source. Are known.

  The rotating shaft member of the vehicle headlamp described in Patent Document 1 includes a first light distribution generation unit that generates a light distribution pattern for the left light distribution low beam along the circumferential direction of the rotation center thereof, and a right light distribution low beam. A second light distribution generation unit for generating a light distribution pattern for use, and a third light distribution generation unit for generating a light distribution pattern for high beam. When the rotating shaft member is rotated by a predetermined angle by the shade driving mechanism (driving member), a part of the reflected light from the reflector passes through any one of the first to third light distribution generation units and has a desired distribution. A light pattern is formed.

JP 2004-349120 A

  By the way, in the vehicle headlamp described in Patent Document 1, when the rotation shaft member is automatically rotated according to the traveling state of the vehicle, the rotation shaft member is selectively selected by a shade drive mechanism such as a step motor. Must be driven to. At this time, a failure may occur in the step motor itself, the control circuit, or the like, and the step motor may not be driven. In particular, if the motor breaks down during high beam irradiation, it is not possible to automatically switch to low beam irradiation, which may cause glare to the oncoming vehicle.

  Accordingly, an object of the present invention is to provide a vehicular headlamp that has an excellent fail-safe function and can irradiate a low-beam light distribution pattern even if a drive member of a shade member fails.

The above object of the present invention is achieved by the following.
(1) a projection lens disposed on an optical axis extending in the vehicle longitudinal direction;
A light source disposed on the optical axis behind the rear focal point of the projection lens;
A reflector that reflects light from the light source forward and closer to the optical axis;
A vehicular headlamp comprising a cylindrical shade member that is rotatable about a rotation center extending in a vehicle width direction,
A low beam distribution pattern forming unit that forms a low beam distribution pattern, a first light distribution pattern forming unit that forms a first light distribution pattern, and a second light distribution pattern are formed in the circumferential direction on the outer peripheral surface of the shade member. A second light distribution pattern forming unit is provided,
A biasing member that constantly biases the shade member to a low beam light distribution pattern position where the low beam light distribution pattern forming unit is located in the vicinity of the rear focal point of the projection lens;
The shade member is rotated to one side from the low beam light distribution pattern position, and the shade member is located at the first light distribution pattern position where the first light distribution pattern forming portion is located in the vicinity of the rear focal point of the projection lens. A first stopper for positioning
The shade member is rotated at the second light distribution pattern position where the second light distribution pattern forming portion is located near the rear focal point of the projection lens. A second stopper for positioning;
And a driving member for rotating the shade member toward the first light distribution pattern position or the second light distribution pattern position against a biasing force of the biasing member. light.
(2) The shade member extends in a radial direction from the rotation center, and moves toward the first stopper or the second stopper against the urging force of the urging member when the shade member is rotated. Having an arm member to be
The vehicular headlamp according to (1), wherein the urging member urges the distal end side of the arm member.

  According to the vehicle headlamp of the present invention, even if the drive member fails in a state where the low beam light distribution pattern forming portion of the shade member is not located near the rear focal point of the projection lens, the biasing member is Since the member is constantly biased to the low beam light distribution pattern position, the shade member returns to the low beam light distribution pattern position, and a low beam light distribution pattern is always formed. That is, if the drive member breaks down, the vehicle emits a low beam, so that it is possible to reliably avoid a situation in which the vehicle continues to travel with the high beam and gives glare to the oncoming vehicle. Therefore, according to this invention, the safe vehicle headlamp excellent in the fail-safe function can be provided.

  Further, according to the vehicle headlamp of the present invention, the drive member may simply rotate the shade member forward and backward toward the first light distribution pattern position or the second light distribution pattern position. The first stopper or the second stopper is used. Therefore, since the shade member does not need to be rotated by a predetermined angle to be stationary, a step motor capable of controlling the rotation angle is not required, and an inexpensive DC motor or the like can be used as the drive member. Therefore, a safe vehicular headlamp can be provided at low cost.

  Furthermore, since the front end side of the arm member is urged by the urging member, a large moment can be generated on the front end side of the arm member even if the urging member having a small urging force is used. Therefore, a safe vehicular headlamp can be provided at a lower cost.

It is a longitudinal cross-sectional view of the vehicle headlamp which concerns on one Embodiment of this invention. It is II-II arrow sectional drawing of the vehicle headlamp of FIG. It is a principal part perspective view of the vehicle headlamp shown in FIG. FIG. 4 is a sectional view of the shade member shown in FIG. 3 taken along line IV-IV. 5A is an operation diagram when the shade member is positioned at the first light distribution pattern position, and FIG. 5B is an operation diagram when the shade member is positioned at the second light distribution pattern position.

  Hereinafter, a vehicle headlamp according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 to 5 show a vehicle headlamp according to an embodiment of the present invention.

With reference to FIG. 1, a vehicular headlamp 1 according to the present embodiment has a lamp unit 5 housed in a lamp chamber 4 defined by a transparent transparent cover 2 and a lamp body 3.
The lamp unit 5 is supported by the lamp body 3 via an aiming mechanism 6 including an aiming screw 6a and an aiming nut 6b. The aiming mechanism 6 is a mechanism for finely adjusting the mounting position and the mounting angle of the lamp unit 5 by adjusting the tightening by the aiming nut 6b. In a normal state, the aiming mechanism 6 is adjusted so that the optical axis Ax of the lamp unit 5 extends in a downward direction by about 0.5 to 0.6 degrees with respect to the vehicle front-rear direction.

  The lamp unit 5 is a projector-type lamp unit, and includes a projection lens 8 disposed on an optical axis Ax extending in the vehicle front-rear direction, and a rear focal point F of the projection lens 8 with the bulb axis aligned with the optical axis Ax. Also, a light source bulb (light source) 10 such as a discharge bulb or a halogen bulb arranged on the rear side, and the light L1 and L2 emitted from the light source bulb 10 with the light source bulb 10 inserted and fixed toward the front are close to the optical axis Ax. And a reflector 13 that reflects the light beam and a rear edge F near the optical axis Ax in the vicinity of the rear focal point F, and shields a part of the reflected light from the reflector 13 and a part of the direct light from the light source bulb 10. A cylindrical shade member 20 that forms a cut-off line of the light distribution pattern, a DC motor (drive member) 30 (see FIG. 2) that rotates the shade member 20, and a projection And a substantially cylindrical holder 17 which is a connecting means, both being interposed between the front end opening edge of the lens 8 and the reflector 13.

  In the present embodiment, an auxiliary shade 18 is integrally formed with the holder 17. The auxiliary shade 18 includes an upper auxiliary shade 18a positioned at the upper part of the holder inner space, and a lower auxiliary shade 18b provided at a position lower than the optical axis Ax on the lower side of the holder inner space. The auxiliary shade 18 shields the reflector reflected light passing below the shade member 20 and shields stray light that is about to enter the projection lens 8.

  The projection lens 8 is a plano-convex lens having a convex front surface and a flat rear surface, and projects the image on the focal plane including the rear focal point F forward as a reverse image.

  In the present embodiment, the light source bulb 10 is a metal halide bulb having a light emitting portion 10a that emits light by discharge on a bulb axis (center axis). The light source bulb 10 is inserted and fixed to the reflector 13 from the rear of the optical axis Ax in a state where the bulb axis coincides with the optical axis Ax.

  As shown in FIG. 2, the reflector 13 has a reflection surface 13a having a substantially elliptical spherical shape with the optical axis Ax passing through the light emitting portion 10a as a central axis. The reflecting surface 13a has a cross-sectional shape including the optical axis Ax set to a substantially elliptical shape with the center position of the light emitting unit 10a as the first focus (F1) and the vicinity of the rear focus F of the projection lens 8 as the second focus. The light from the light emitting unit 10a is condensed and reflected toward the optical axis Ax toward the front. The eccentricity of the reflecting surface 13a is set so as to gradually increase from the vertical cross section toward the horizontal cross section.

  The shade member 20 is arranged along the horizontal axis (rotation center) Hx extending in the vehicle width direction in the vicinity below the optical axis Ax, and is configured to be rotatable around the horizontal axis Hx. The shade member 20 is made of a substantially semi-cylindrical metal member having support shafts 21a and 21b arranged on the horizontal axis Hx at both ends.

  On the outer peripheral surface of the cylindrical shade member 20, as shown in FIGS. 3 and 4, a right side high beam light distribution pattern forming unit 20A (first light distribution pattern forming unit), a low beam light distribution pattern forming unit 20C, and both side high beam light distributions. A pattern forming unit 20B (second light distribution pattern forming unit) is sequentially formed in the circumferential direction.

  These light distribution pattern forming portions 20A to 20C are portions where the radial distance from the horizontal axis Hx to the outer peripheral surface of the shade member 20 is changed in a predetermined angle region. For example, since most of the reflected light from the reflector can pass through the region having a small radial distance, a light distribution pattern that can irradiate light up to the upper part of the road surface can be formed. On the other hand, since the region having a large radial distance blocks most of the reflected light from the reflector, a light distribution pattern for irradiating light only in the vicinity of the vehicle can be formed. These shapes are appropriately combined to form a low beam light distribution pattern, a right-side high beam light distribution pattern, or both-side high beam light distribution patterns.

  With reference to FIG. 2, the support shafts 21 a and 21 b of the shade member 20 are rotatably supported by the holder 17. A first gear member 22 is provided on one of the support shafts 21a of the shade member 20 so as not to be relatively rotatable. A drive shaft of a DC motor 30 as a drive member is provided with a second gear member 31 that is fixed so as not to be relatively rotatable. The first gear member 22 and the second gear member 31 are engaged with each other to drive the DC motor 30. A force is transmitted to the shade member 20.

  Referring to FIG. 3, the other support shaft 21 b of the shade member 20 is provided with an arm member 40 that is fixed so as not to rotate relative to the shade member 20. The arm member 40 includes a main body portion extending in the radial direction from the rotation axis of the shade member 20 and an extending portion 41 extending in the longitudinal direction of the shade member 20 from the radial tip of the main body portion.

  Further, a torsion spring 50 (biasing member) is provided on the shade member 20 adjacent to the arm member 40. The winding portion 51 of the torsion spring 50 is provided on the rotation shaft of the shade member 20, and the pair of straight portions 52 a and 52 b that extend linearly from the winding portion 51 in the radial direction are extended portions 41 of the arm portion 40. The pair of straight portions 52a and 52b is sandwiched from the front and rear, and a low beam stopper 60C described later is sandwiched between the distal ends of the pair of linear portions 52a and 52b.

  The first stopper 60A is fixed to the front of the shade member 20, the second stopper 60B is fixed to the rear, and the low beam stopper 60C is fixed to the holder 17 below. These stoppers 60A to 60C are provided on the support shaft 21b side of the shade member 20 so that the straight portions 52a and 52b of the torsion spring 50 can come into contact with each other.

  In addition, the space | interval of the front-end | tip of a pair of linear part 52a, 52b in the no-load state of the torsion spring 50 is made smaller than the front-back direction dimension (left-right direction of FIG. 2) of the extension part 41 of the arm member 40. Furthermore, the dimension in the front-rear direction of the low beam stopper 60 </ b> C is made the same as or slightly larger than the dimension in the front-rear direction of the extending portion 41 of the arm member 40. As a result, the pair of linear portions 52a and 52b of the torsion spring 50 sandwich the extending portion 41 and the low beam stopper 60C with a predetermined urging force.

  The shade member 20 is rotatable to a low beam light distribution pattern position, a right side high beam light distribution pattern position (first light distribution pattern position), and a both-side high beam light distribution pattern position (second light distribution pattern position). When the shade member 20 rotates and the right side high beam light distribution pattern forming part 20A, the both side high beam light distribution pattern forming part 20B, and the low beam light distribution pattern forming part 20C are respectively located in the vicinity of the rear focal point F of the projection lens 8, the right side A high beam light distribution pattern, a high beam distribution pattern on both sides, and a low beam light distribution pattern can be irradiated.

  The right high beam light distribution pattern position means that, as shown in FIG. 5A, the shade member 20 is rotated so that the right high beam light distribution pattern forming unit 20A is positioned in the vicinity of the rear focal point F of the projection lens 8, and the right high beam light distribution pattern. It is a position where can be irradiated. In other words, the extended portion 41 of the arm member 40 is in a state positioned on the first stopper 60A side.

  The both-side high beam light distribution pattern position means that, as shown in FIG. 5B, the shade member 20 is rotated so that the both-side high beam light distribution pattern forming unit 20B is positioned in the vicinity of the rear focal point F of the projection lens 8, It is a position where can be irradiated. In other words, the extended portion 41 of the arm member 40 is in a state positioned on the second stopper 60B side.

  The low beam light distribution pattern position refers to the shade member 20 so that the low beam light distribution pattern forming portion 20C is positioned in the vicinity of the rear focal point F of the projection lens 8 as shown by a two-dot chain line in FIG. 3 and FIGS. 5A and 5B. Is a position where the low beam distribution pattern can be irradiated. In other words, the extending portion 41 of the arm member 40 is in a state positioned on the low beam stopper 60C side.

  By the way, the shade member 20 is urged by the urging force of the torsion spring 50 so as to be always positioned at the low beam light distribution pattern position. That is, the pair of linear portions 52a and 52b of the torsion spring 50 brings together the extended portion 41 of the arm portion 40 fixed to the shade member 20 and the low beam stopper 60C fixed to the holder 17 together with a predetermined urging force. Since it is sandwiched, the shade member 20 is always urged to the position of the low beam light distribution pattern.

  When the DC motor 30 is rotated forward from the low beam light distribution pattern position to the state shown in FIG. 5A and the shade member 20 is rotated toward the right high beam light distribution pattern position, the extension 41 of the arm member 40 is moved to the torsion spring 50. One straight portion 52a is lifted. At this time, since the other linear portion 52b of the torsion spring 50 remains in contact with the low beam stopper 60C, the torsion spring 50 tries to return to the original shape, that is, to return the shade member 20 to the low beam distribution pattern position. The restoring force to generate is generated. Thus, the DC motor 30 rotates the shade member 20 against the restoring force (biasing force) of the torsion spring 50.

  The rotating motion of the shade member 20 by the DC motor 30 is stopped when one linear portion 52a of the torsion spring 50 contacts the first stopper 60A as shown in FIG. 5A. The first stopper 60A is a position where the shade member 20 is rotated so that the right high beam light distribution pattern forming unit 20A is positioned in the vicinity of the rear focal point F of the projection lens 8 and the rotational movement of the shade member 20 is stopped. Is provided. That is, the first stopper 60A positions the shade member 20 at the right high beam light distribution pattern position.

  On the other hand, when the DC motor 30 is reversed so that the shade member 20 is rotated from the low beam light distribution pattern position to the other as shown in FIG. 5B, the other linear portion 52b is lifted against the urging force of the torsion spring 50. The shade member 20 is rotated until the other straight portion 52b contacts the second stopper 60B. In this state, the high beam distribution pattern forming portions 20B on both sides of the shade member 20 are located in the vicinity of the rear focal point F of the projection lens 8.

  Here, similarly to the first stopper 60A, the second stopper 60B is located at a position where the shade member 20 is rotated so that the high beam distribution pattern forming portion 20B on both sides is located in the vicinity of the rear focal point F of the projection lens 8. The shade member 20 is provided at a position to stop the rotational movement. That is, the second stopper 60B positions the shade member 20 at the high beam distribution pattern positions on both sides.

  Note that when the energization to the DC motor 30 is cut off, no driving force is generated in the DC motor 30. In this state, since only the restoring force of the torsion spring 50 is applied to the shade member 20, the shade member 20 is rotated so as to be positioned at the low beam light distribution pattern position. That is, when the energization to the DC motor 30 is released, the shade member 20 is automatically rotated to the low beam light distribution pattern position.

  As described above, when switching from the low beam light distribution pattern to the right side high beam light distribution pattern or the both side high beam light distribution pattern, the first stopper 60A or the second stopper 60B positions the shade member 20, so that the DC motor 30 is simply operated. The shade member 20 may be rotated toward the right side high beam light distribution pattern position or the both side high beam light distribution pattern position by forward and reverse rotation. That is, since it is not necessary to rotate the shade member 20 by a predetermined angle and stop it, a step motor or the like that can control the rotation angle is not required. Since the driving member of the present invention only needs to have a mechanism capable of generating driving force in two directions, the present embodiment employs an inexpensive DC motor 30 to provide a safe vehicular headlamp 1 at a low cost. be able to.

  Furthermore, since the shade member 20 is automatically rotated to the low beam light distribution pattern position when the energization to the DC motor 30 is cut off, the DC motor 30 should malfunction and a driving force is generated in the DC motor 30. Even if it disappears, a low beam distribution pattern is always formed. Therefore, the vehicle headlamp 1 excellent in a safer fail-safe function is realized.

In the above-described embodiment, the structure in which the shade member 20 is rotated by the torsion spring 50 is described as an example, but a coil spring may be used as the biasing member instead of the torsion spring 50.
In this case, one end of the coil spring is fixed to the opposite side in the radial direction of the low beam distribution pattern forming portion 20B of the shade member 20, and the other end is fixed to the lower side of the shade member 20 of the holder 17. When the shade member 20 is located at the low beam light distribution pattern position, the longitudinal dimension of the coil spring is minimized, and when the shade member is located at a position other than the low beam light distribution pattern position, the coil spring is extended. The shade member 20 can always be biased to the low beam distribution pattern position.

  Further, in the above-described embodiment, the pair of linear portions 52a and 52b of the torsion spring 50 are in contact with the first stopper 60A or the second stopper 60B, but the extending portion 41 of the arm member 40 is the first stopper 60A. Or it is good also as a structure contact | abutted to the 2nd stopper 60B.

  Moreover, although the right side high beam light distribution pattern was provided as a 1st light distribution pattern formation part, and the both-sides high beam light distribution pattern was provided as a 2nd light distribution pattern formation part, it was not restricted to this structure. By changing the shape of the outer peripheral surface of the shade member 20, the first light distribution pattern forming unit 20A and the second light distribution pattern forming unit 20B are changed to the left high beam light distribution pattern, town mode light distribution pattern, rain mode light distribution pattern, etc. It may be formed.

  In the above embodiment, the arm member 40, the torsion spring 50, the first stopper 60 </ b> A, the second stopper 60 </ b> B, and the low beam stopper 60 </ b> C are illustrated inside the holder 17. A torsion spring 50, a first stopper 60A, a second stopper 60B, a low beam stopper 60C, and the like may be provided.

DESCRIPTION OF SYMBOLS 1 Vehicle headlamp 8 Projection lens 10 Light source 13 Reflector 17 Holder 20 Shade member 20A Right side high beam light distribution pattern formation part (1st light distribution pattern formation part)
20B Both-sides high beam light distribution pattern formation part (2nd light distribution pattern formation part)
20C Low beam light distribution pattern forming unit 30 DC motor 40 Arm member 50 Torsion spring (urging member)
60A First stopper 60B Second stopper 60C Low beam stopper

Claims (2)

A projection lens disposed on an optical axis extending in the vehicle longitudinal direction;
A light source disposed on the optical axis behind the rear focal point of the projection lens;
A reflector that reflects light from the light source forward and closer to the optical axis;
A vehicular headlamp comprising a cylindrical shade member that is rotatable about a rotation center extending in a vehicle width direction,
A low beam distribution pattern forming unit that forms a low beam distribution pattern, a first light distribution pattern forming unit that forms a first light distribution pattern, and a second light distribution pattern are formed in the circumferential direction on the outer peripheral surface of the shade member. A second light distribution pattern forming unit is provided,
A biasing member that constantly biases the shade member to a low beam light distribution pattern position where the low beam light distribution pattern forming unit is located in the vicinity of the rear focal point of the projection lens;
The shade member is rotated to one side from the low beam light distribution pattern position, and the shade member is located at the first light distribution pattern position where the first light distribution pattern forming portion is located in the vicinity of the rear focal point of the projection lens. A first stopper for positioning
The shade member is rotated at the second light distribution pattern position where the second light distribution pattern forming portion is located near the rear focal point of the projection lens. A second stopper for positioning;
And a driving member for rotating the shade member toward the first light distribution pattern position or the second light distribution pattern position against a biasing force of the biasing member. light. The shade member extends in a radial direction from the rotation center, and moves toward the first stopper or the second stopper against the urging force of the urging member when the shade member is rotated. Have
The vehicle headlamp according to claim 1, wherein the biasing member biases the distal end side of the arm member.

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