JP2005243349A - Projection type automobile head lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a temperature rise without enlarging a mounting space for a motor. <P>SOLUTION: This projection type automobile head lamp is equipped with an almost bowl-shaped reflector 26, a light source (bulb) 24 disposed at the first focus F1 of the reflector 26, a projection lens 28 disposed in front of the reflector 26, a rotary shade 34 for controlling light distribution which is disposed in the vicinity of the second focus F2 of the reflector 26 to intercept a part of light directed to the projection lens 28 by being reflected by the reflector 26, a stepping motor 58 to rotate the rotary shade 34, helical gears 62, 64, spur gears 68, 70, a connecting shaft 66 which forms a driving force transmitting mechanism to transmit the driving force of the stepping motor 58 to the rotary shade 34, and the stepping motor 58 is disposed in the side region on the outside of the reflector 26 so that its output axis 60 is orthogonal to the rotation shaft 36. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection headlamp that projects and distributes light reflected from a substantially bowl-shaped reflector forward by a projection lens, and in particular, a projection type automobile that can switch light distribution by rotating a rotary shade. It relates to a headlamp.

As a related art of this type of headlamp, there is a substantially bowl-shaped reflector, a light source arranged at a first focus of the reflector, a projection lens arranged in front of the second focus of the reflector, and a first reflector of the reflector. A rotating shade for light distribution that is rotatably arranged in the vicinity of the two focal points, blocks a part of the light reflected by the reflector and travels toward the projection lens, and a motor that generates a driving force for rotating the rotating shade; It is equipped with a plurality of gears that transmit the driving force of the motor to the rotary shade, and the rotary shade is composed of a stepped cylinder and a horizontal support shaft formed at a position eccentric from the axis of the stepped cylinder. A clear cut line is formed by the outer shape of the stepped cylindrical body (the shape of the side edge), and the rotating shade is rotated forward and backward by driving the motor, thereby clearing the light distribution pattern. That to adjust the position of the cut line in the vertical direction is proposed (see Patent Document 1).
JP-A-6-139802 (2nd to 4th pages, FIGS. 1 to 5)

  In the prior art described above, when the output shaft of the motor, which is a drive source for rotationally driving the rotary shade, is connected to the horizontal support shaft of the rotary shade via the reduction gear train, the output shaft of the motor and the horizontal axis of the rotary shade are connected. Since the support shafts are arranged in parallel to each other, it is necessary to place the motor on the lower side of the rotary shade, and the motor protrudes greatly below the lens holder provided between the projection lens and the reflector. For example, there is a problem that the space below the rotary shade becomes large.

  In addition, since the rotary shade is provided in a position where the reflected light from the reflector is condensed in a substantially sealed space, when the rotary shade is exposed to high temperature and the heat of the rotary shade is transmitted to the motor via the gear train, There is also a problem that the temperature of the motor rises and a necessary output may not be obtained from the motor depending on the temperature.

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to suppress the temperature rise of the motor without increasing the mounting space of the drive motor for rotating the rotary shade.

  In order to achieve the above object, in the projection type automotive headlamp according to claim 1, a substantially saddle-shaped reflector, a light source arranged at a first focus of the reflector, and a second focus of the reflector A projection lens disposed in front of the reflector, and substantially in the vicinity of the second focal point of the reflector, extending in a direction substantially orthogonal to the optical axis of the projection lens, and rotatably disposed; A rotation shade for light distribution control configured to form a predetermined light distribution pattern with a side edge portion blocking a part of the light from the reflector side toward the projection lens, and for rotating the rotation shade A projection type automotive headlamp comprising: a motor that generates a driving force; and a driving force transmission mechanism that transmits the driving force of the motor to the rotary shade. In the region of the coater side surface side, and the output shaft are arranged to be perpendicular to the rotary shade.

  Further, as a driving force transmission mechanism interposed between the motor and the rotary shade, a gear mechanism such as a pair of helical gears, a pair of bevel gears, a worm and a worm wheel can be considered.

  (Operation) Since the motor is arranged in the region on the side surface side of the reflector so that the output shaft thereof is orthogonal to the rotation axis of the rotary shade, the motor is arranged behind the curved outer surface of the reflector. By effectively utilizing the area on the side of the motor, the motor does not protrude significantly in the vertical direction or the front-rear direction of the reflector. That is, it is possible to prevent the motor mounting space from increasing. Further, the driving force transmission mechanism suppresses the heat of the rotary shade from being directly transmitted to the motor, thereby suppressing the temperature rise of the motor.

  According to a second aspect of the present invention, in the projection type automotive headlamp according to the first aspect, the driving force transmission mechanism includes a driving gear that is attached to the output shaft of the motor, and a driven gear that meshes with the driving gear. A first orthogonal transformation gear pivotally attached to the rotary shade; a second orthogonal transformation gear meshing with the first orthogonal transformation gear; and the driven gear and the second orthogonal transformation supported rotatably. And a connecting shaft for connecting the gear.

  (Operation) Since the driving force transmission mechanism for transmitting the driving force of the motor to the rotary shade is constituted by a plurality of gear trains, the distance between the rotary shade and the motor can be increased, and the length of the connecting shaft is equivalent. As a result, the heat transfer path becomes longer, and the heat transfer of the rotary shade to the motor is further suppressed, and the temperature rise of the motor is further suppressed.

  Further, since the rotation support shaft of the rotary shade and the output shaft of the motor can be arranged on substantially the same plane, the motor does not protrude in the vertical direction of the reflector.

  According to a third aspect of the present invention, in the projection type automotive headlamp according to the second aspect, the drive gear, the driven gear, the first orthogonal transformation gear, and the second orthogonal transformation gear are each constituted by a helical gear. The directions of the teeth of the helical gears are set so that the thrust forces acting in the axial direction of the connecting shaft in the respective gear meshing portions are opposite to each other.

  (Operation) Since the axial thrust force of the connecting shaft generated at the helical gear meshing portion cancels each other, the thrust force generated at the gear meshing portion when rotating the rotary shade is applied to the output shaft of the motor as a load. Does not work.

  According to a fourth aspect of the present invention, in the projection type automotive headlamp according to any one of the first to third aspects, at least one of the plurality of gears constituting the driving force transmission mechanism is made of resin. .

  (Operation) Since at least one of the plurality of gears constituting the driving force transmission mechanism is made of resin, heat on the rotary shade side is transmitted to the motor as compared with a structure in which all gears are made of metal. hard.

  As is apparent from the above description, the projection type automotive headlamp according to claim 1 can suppress an increase in the temperature of the motor without increasing the mounting space of the motor and can improve the reliability of the motor. .

  According to the second aspect, the temperature rise of the motor can be further suppressed without increasing the mounting space of the motor, and the reliability of the motor can be further improved.

  According to the third aspect, since the load on the motor due to the thrust generated in the gear meshing portion can be reduced, the reliability of the motor can be further improved.

  According to the fourth aspect, the temperature rise of the motor can be further suppressed, and the reliability of the motor can be further improved.

  Next, embodiments of the present invention will be described based on examples. 1 to 5 show a projection type automotive headlamp according to an embodiment of the present invention. FIG. 1 is an exploded perspective view of an optical projection unit which is a main part of the projection type automotive headlamp. FIG. FIG. 3 is a side view of the same light projection unit, FIG. 4 is a plan view of the same light projection unit partially shown in cross section, and FIG. It is the rear view which removed the reflector from the light projection unit and was seen from back.

  In these drawings, a lamp body 10 of a projection type automobile headlamp is formed in a container shape, and a front lens 12 is assembled to a front opening of the lamp body 10 to define a lamp chamber S. (See FIG. 2). In the lamp chamber S, the light projection unit can adjust the tilt of the irradiation axis (the optical axis of the light projection unit 14) L of the headlamp by an aiming mechanism, and can swivel the same optical axis L in the left-right direction by the swivel mechanism. 14 is housed.

  That is, the light projection unit 14 is provided with a pair of upper and lower support shafts 22a and 22b coaxially, and an upper surface of the unit frame 100 (see FIG. 5) having a substantially rectangular frame shape in front view with an opening (opening 101) at the center. The support shafts 22a and 22b are supported on the wall 100a and the lower wall 100b, and the light projection unit 14 is configured to be swingable in the left-right direction around the swivel axis L22 (see FIGS. 1 and 5) with respect to the unit frame 100. Further, the lower support shaft 22 b is configured by an output shaft of the swivel actuator 40 fixed to the lower surface wall 100 b of the unit frame 100. The support shaft 22b, which is an output shaft capable of rotating in the forward and reverse directions of the swivel actuator 40, is fixedly integrated with the light projection unit 14 (the lens holder 30 thereof), and the drive of the swivel actuator 40 (the rotation of the support shaft 22b) ) Causes the light projection unit 14 to swing (swivel) in the left-right direction. For example, the swivel actuator 40 is driven in conjunction with the steering of the steering wheel, the light projection unit 14 is swiveled in the steering direction of the steering wheel and in proportion to the steering amount, and the front of the steering direction of the vehicle is illuminated brightly.

  On the other hand, the aiming mechanism interposed between the lamp body 10 and the unit frame 100 is not illustrated and described, but is provided at a position orthogonal to the front view with respect to the left and right aiming screws, the upper and lower aiming screws, and the two aiming screws. It is mainly composed of a tilting fulcrum such as a ball joint. Then, in FIG. 5 showing a rear view when the reflector 26 is detached from the light projection unit 14 integrated with the unit frame 100 and viewed from the rear, the upper left corner portion of the unit frame 100 is screwed into the upper and lower aiming screws. A rectangular hole 102a which is long at the top and bottom when the nut member is inserted, and a rectangular hole 102b which is long at the left and right when the nut member is screwed into the left and right aiming screws are provided at the lower right corner portion of the unit frame 100. A circular hole 102c for inserting a tilting fulcrum component member such as a ball joint is formed in the lower left corner portion of 100. In this embodiment, the light projection unit 14 is supported by the aiming mechanism. However, when the light projection unit 14 is supported by the auto leveling mechanism instead of the aiming mechanism, the leveling fixed to the lamp body 10 is performed. A slider (not shown) capable of moving back and forth of an actuator (not shown) extends forward, and a nut member that supports the tip of the slider is inserted into the hole 102a. .

  When the upper and lower aiming screws and the left and right aiming screws are rotated, the unit frame 100 and the light projection unit 14 are tilted integrally. Tilt adjustment (aiming) of the optical axis L in the vertical and horizontal directions can be performed. Reference numeral 18 denotes an extension reflector that surrounds the light projection unit 14 and is disposed so as not to interfere with the unit frame 100 (light projection unit 14) that can be tilted and swiveled.

  The light projection unit 14 includes an aluminum die-cast reflector 26 having an approximately ellipsoidal shape with a front surface side to which the discharge bulb 24 is inserted and a substantially elliptical shape in front view, a projection lens 28 disposed in front of the reflector 26, An annular mounting bracket for holding the projection lens 28 with a structure in which an aluminum die-cast lens holder 30 formed in a cylindrical shape and whose axial rear end is screwed to the front side of the reflector 26 is integrated. 32 is fixed to the lens holder 30 by screws.

  An ellipsoidal reflecting surface 26a subjected to aluminum vapor deposition is formed inside the reflector 26. The ellipsoidal reflecting surface 26a has a first focal point F1 and a second focal point F2, and the discharge valve 24 is located at the first focal point F1. The discharge center is located. Further, near the second focal point F2 and at the focal position of the projection lens 28, a metal (for example, made of aluminum) for forming a clear cut line by blocking a part of the light reflected by the reflector 26 and traveling toward the projection lens 28. ) Rotation shade 34 is provided. Light emitted from the bulb 24 reflected by the reflector 26 is collected on the rotary shade 34, and the collected light is guided to the front of the rotary shade 34. The projection lens 28 converts the light into substantially parallel light in front of the headlamp. Projected light distribution.

  The rotary shade 34 includes a rotary shaft 36 arranged in a direction orthogonal to the irradiation axis L of the headlamp (the optical axis of the projection lens 28) L, and a plurality of rotary shades 34 arranged at predetermined intervals in the circumferential direction of the rotary shaft 36. The light shielding plates 38a, 38b, 38c, 38d, 38e, and 38f are provided. Details of the shape of the light shielding plates 38a to 38f will be described in detail later. When the stepping motor 58 is driven, the rotary shade 34 (rotary shaft 36) rotates in the forward and reverse directions, and each light shielding plate 38 is created each time the light shielding plate 38 is positioned at the irradiation axis (optical axis) L. A clear cut line corresponding to the light distribution pattern is formed.

  Specifically, as shown in FIGS. 3 to 5, disks 42 and 44 for supporting the light shielding plates 38 a to 38 f are fixed to both ends of the rotating shaft 36. Outside the disks 42 and 44, a metal bearing bracket 50 extending across the lens holder 30 is rotatably supported via bearings 46 and 48. The bearing bracket 50 is screwed to the lens holder 30, and the bearings 46 and 48 are inserted together with the rotary shaft 36 into a through hole (not shown) formed in the bearing bracket 50. A wet cam 52, which is a metal eccentric cam, is attached to one end of the rotating shaft 36 in the axial direction (left side in FIG. 4). A driving force transmission mechanism is provided between the wet cam 52 and the bearing 48. 56 is arranged.

  The driving force transmission mechanism 56 is interposed between the stepping motor 58 and the rotary shade 34. As shown in FIG. 4, the stepping motor 58 is a region on the side of the reflector 26, that is, near the curved portion of the reflector 26. Is located in the area. The stepping motor 58 is configured as a drive source that generates a driving force for rotationally driving the rotary shade 34, and its output shaft 60 is arranged in a direction orthogonal to the rotary shaft 36 of the rotary shade 34. When the driving force of the stepping motor 58 is transmitted to the rotary shaft 36 via the driving force transmission mechanism 56, the driving force transmission mechanism 56 is configured using a plurality of gear trains.

  That is, the driving force transmission mechanism 56 is attached to the rotation shaft 36 of the rotary shade 34 and is formed with a helical gear (first helical gear) 62 formed of brass and a helical gear (helical gear) 62. A synthetic resin helical gear (second helical gear) 64 meshed with the helical gear 62 below, a brass connecting shaft 66 connected to the helical gear (helical gear) 64, and an axis of the connecting shaft 66 A brass spur gear 68 connected to the end of the direction and a brass spur gear 70 meshing with the spur gear 68 and mounted on the output shaft 60 of the stepping motor 58 are provided. A metal disk 72 (see FIGS. 3 and 4) is fixed in the middle of the connecting shaft 66, and a metal stopper pin 74 projects from the outer periphery of the disk 72. The helical gear 64 is configured using a resin (for example, PEEK resin or nylon resin) in consideration of heat resistance as an intermediate gear. The flat gear 70 that is a driving gear transmits the driving force of the stepping motor 58 to the flat gear 68 that is the driven gear, and the driving force transmitted to the flat gear 68 is transmitted to the helical gear 64 via the connecting shaft 66. The driving force transmitted to the helical gear 64 is transmitted to the rotary shade 34 (rotary shaft 36) via the helical gear 62. In this case, the direction of the driving force is converted by 90 degrees by the helical gear 62 and the helical gear 64. That is, the pair of helical gears 62 and 64 constitutes an orthogonal conversion gear.

  Further, the stepping motor 58 is fixed to a motor bracket 76 fixed to the lens holder 30, and a connecting shaft 66 that connects the flat gear 68 and the helical gear 64 is a bearing 78, 80 that is inserted into the motor bracket 76. (Refer to FIG. 3). As shown in FIGS. 3, 4, and 6 (c), the motor bracket 76 is formed with stopper portions 77 (77 a, 77 b) that protrude on the rotation path of the stopper pin 74 and latch the stopper pin 74. When the rotary shade 34 (connection shaft 66) rotates in the forward direction, the stopper pin 74 comes into contact with one side surface 77b of the stopper portion 77 as shown in FIG. When the connecting shaft 66) is prevented from further rotation, on the other hand, when the rotary shade 34 (connecting shaft 66) 6 rotates in the reverse direction, as shown in FIG. In contact with the other side surface 77a of the portion 77, the rotary shade 34 (connection shaft 66) is prevented from further rotation. That is, the rotary shade 34 (connection shaft 66) can be rotated within a range of 0 to 315 degrees, for example, but further rotation is caused by the contact between the stopper pin 74 and the stopper portion 77 (77a, 77b). It is blocked by contact. Thereby, initial setting (initialization) for correcting a positional shift in the drive control of the stepping motor 58 can be performed. 1 and 4 is a position detector (potentiometer) for detecting the rotation angle of the stepping motor 58.

  On the other hand, a wet shade 82 having a rectangular shape in front view is disposed above the rotary shade 34 so as to be movable up and down. The wet shade 82 is formed in a U-shape when viewed from the front, and is integrally formed on the tip end side of the swing arm 84 disposed so as to cross the notch 30 a on the oblique upper side of the lens holder 30. The wet shade 82 descends (hangs down) to a region near the irradiation axis (optical axis) L in the region above the rotary shade 34 only when forming a light distribution pattern during rainy weather as a shade for rainy weather. In other cases, it moves far away from the rotary shade 34 and moves toward the lens holder 30 so that the light distribution pattern formed by the rotary shade 34 is not affected.

  Further, the base end side of the arm 84 is integrated with a cam follower 86 formed of a leaf spring, the tip end side of the cam follower 86 is pressed against the outer peripheral surface of the wet cam 52, and the base end side thereof is via a pin 88. The motor bracket 76 is swingably fixed. A coil spring 90 is mounted between the base end portion of the cam follower 86 and the motor bracket 76. One end side 90a of the coil spring 90 is locked to the motor bracket 76, the other end side 90b is locked to the upper surface side of the cam follower 86, and the spring force (elastic force) of the coil spring 90 is determined by the cam follower 86 by the wet cam 52. It acts in the direction which presses the outer peripheral surface.

  The wet cam 52 rotates in the forward / reverse direction together with the rotary shade (rotary shaft 36), and while the cam follower 86 is in contact with the outer peripheral surface of the long diameter side of the wet cam 52, as shown by phantom lines in FIG. When the wet shade 82 is disposed at a position away from the rotary shade 34 (position far away from the rotary shade 34), and the cam follower 86 contacts the outer peripheral surface of the wet cam 52 on the short diameter side, FIG. As indicated by the solid line, the wet shade 82 hangs down in the vertical direction and is disposed near the upper portion of the rotary shade 34, and at the same time, the light shielding plate 38d is located near the irradiation axis (optical axis) L.

  Specifically, as shown in FIG. 6, the light shielding plates 38a to 38f of the rotary shade 34 that are arranged radially with respect to the rotation shaft 36 are opposite to each other in the circumferential direction with reference to the position where the light shielding plate 38a is arranged. In the clockwise direction, the light shielding plate 38b is disposed at 90 °, the light shielding plate 38c at 135 °, the light shielding plate 38d at 180 °, the light shielding plate 38e at 225 °, and the light shielding plate 38f at 315 °. . This is because when the rotary shade 34 is rotated 180 degrees in the forward direction from the initial position shown in FIG. 7A, and the light shielding plate 38d is closest to the optical axis L as shown in FIG. Is in contact with the outer peripheral surface of the short diameter side of the wet cam 52, and the wet shade 82 is suspended in the vertical direction and is disposed in the vicinity of the upper portion of the rotary shade 34.

  In this case, the light shielding plate 38a corresponds to the high beam Hi-L in the left light distribution, the light shielding plate 38b corresponds to the low beam Lo-L in the left light distribution, and the light shielding plate 38c is the high speed beam MW in the left light distribution. The light shielding plate 38d corresponds to the rain beam (wet beam) Wet-L in the left light distribution, the light shielding plate 38e corresponds to the low beam Lo-R in the right light distribution, and the light shielding plate 38f This corresponds to the high beam Hi-R in the right light distribution, and when the driver performs a light distribution switching operation for irradiating one of the beams, the rotary shade 34 is rotated according to the operation. It has become.

  That is, the stepping motor 58 is connected to a control circuit (not shown) via a lead wire (not shown), and the control circuit has a light distribution switching operation switch (not shown) for operation by the driver. ) Is input. Then, by the driver's light distribution switching operation, for example, as shown in FIG. 7A, from the initial position where the left light distribution high beam Hi-L is formed, the low beam Lo-L and the high speed beam MW When a beam to be irradiated is selected in the order of -L, the rain beam (wet beam) Wet-L, the right light distribution low beam Lo-R, and the high beam Hi-R, the control circuit applies to the stepping motor 58. Thus, pulse signals corresponding to the operation positions of the operation switches are sequentially output. Thereby, the stepping motor 58 is rotated in the forward direction, and the light shielding plates 38a to 38f are sequentially moved to positions near the irradiation axis (optical axis) L in the process in which the stepping motor 58 is rotated in the forward direction. It has become.

  Specifically, when an operation for sequentially rotating the rotary shade 34 in the forward direction from the position where the left light distribution high beam Hi-L shown in FIG. 7A is formed, the left light distribution is performed. When the low beam Lo-L is selected, the light shielding plate 38b is positioned in the vicinity of the optical axis L. Next, when the left light distribution high-speed beam MW-L is selected, the light shielding plate 38c is aligned with the optical axis. Next, when the rain light beam (wet beam) Wet-L for left light distribution is selected, the light shielding plate 38d is in the vicinity of the optical axis L. Further, when the right light distribution low beam Lo-R is selected, the light shielding plate 38e is positioned in the vicinity of the optical axis L. Thereafter, when the right light distribution high beam Hi-R is further selected, the light shielding plate 38e is selected. 38f is a position near the optical axis L.

  On the other hand, an operation for sequentially rotating the rotary shade 34 in the reverse direction from the formation position of the high beam Hi-R for right light distribution shown in FIG. 7B is executed, and the low beam Lo-R for right light distribution is executed. , Rain light beam (wet beam) Wet-L for left light distribution, high-speed beam MW-L for left light distribution, low beam Lo-L for left light distribution, and high beam Hi-L for left light distribution When a beam to be irradiated is selected, a pulse signal corresponding to the operation position of the operation switch is sequentially output from the control circuit to the stepping motor 58. Thus, in the process in which the stepping motor 58 rotates in the reverse direction and the stepping motor 58 rotates in the reverse direction, the light shielding plates are arranged in the order of the light shielding plates 38f, 38e, 38d, 38c, 38b, and 38a. It moves to a position near the optical axis (L).

  Next, the shape of the rotary shade 34 when the projection lens 28 side is viewed from the reflector 26 is shown in FIGS. (a) shows the shape of the light-shielding plate 38b for forming the low beam Lo-L in the left light distribution. (b) shows the shape of the light shielding plate 38c for forming the high-speed beam MW-L in the left light distribution. (C) shows the positional relationship between the shape of the light shielding plate 38d and the wet shade 82 for forming the rain beam (wet beam) Wet-L in the left light distribution. (d) shows the shape of the light shielding plate 38e for forming the low beam Lo-R in the right light distribution. (e) shows the shape of the light shielding plates 38a and 38f for forming the high beams Hi-L and Hi-R in the left light distribution and the right light distribution.

  Next, the irradiation light distribution patterns on the screen corresponding to the shade shapes shown in FIGS. 8A to 8E are shown in FIGS. 9A to 9E, and the irradiation light distribution patterns on the road surface are illustrated. 10 (a) to (e). 9 (a) and 10 (d), the light distribution patterns are the same except that the left light distribution and the right light distribution are different. 9 (b) and 10 (c), the light distribution pattern by the light shielding plate is the same. However, in FIG. 9 (c), since there is a wet shade 82, the area near the front of the vehicle is different from the other areas. A dark area A is formed, and it is possible to prevent the beam from reflecting on a wet road surface and causing glare with respect to the oncoming vehicle. 9 and 10, (e) shows the same pattern in which the left light distribution and the right light distribution are distributed as a high beam over a wide range from the front side of the vehicle to a distant place.

  As described above, according to the present embodiment, the stepping motor 58 is disposed on the side surface region outside the reflector 26 so that the output shaft 60 thereof is orthogonal to the rotation shade 34 (the rotation shaft 36 thereof). Is located along the curved outer surface of the reflector 26, and the motor output shaft 60 and the rotary shade 34 (rotary shaft 36 thereof) are arranged on substantially the same plane, so that the mounting space of the stepping motor 58 is light projected. It is possible to prevent the unit 14 from being increased laterally or downward. Further, since the driving force transmission mechanism 56 is interposed between the stepping motor 58 and the rotary shade 34, heat from the rotary shade 34 is prevented from being directly transmitted to the stepping motor 58, and the temperature rise of the stepping motor 58 is suppressed. Can do.

  Furthermore, according to the present embodiment, the rotary shade 34 (rotary shaft 36) is connected to the stepping motor 58 via the driving force transmission mechanism 56 constituted by an orthogonal conversion gear mechanism, so that the rotary shade 34 and the stepping motor are connected. By increasing the distance to 58, it is possible to suppress the heat of the rotary shade 34 from being transmitted to the stepping motor 58. Moreover, since the helical gear 64 is made of resin, heat conduction can be further suppressed. For this reason, even if the heat of the rotary shade 34 reaches 150 ° C., for example, this heat is cooled in the process of being conducted from the rotary shade 34 to the plurality of gears, and the temperature of the stepping motor 58 becomes 110 ° C. or higher. Can be suppressed.

  In this embodiment, since the wet cam 52 having a large outer diameter is fixed to the rotation shaft 36 of the rotary shade 34, the heat of the rotary shade 34 can be obtained by using the wet cam 52 as a heat sink (heat radiating plate). Can be further suppressed from being transmitted to the stepping motor 58.

  Further, in this embodiment, as shown in FIG. 11A, the lower helical gear 64 meshing with the upper helical gear 62 on the rotary shade 34 constituting the gear train of the driving force transmission mechanism 56, and the motor 58 side The lower flat gear 68 that meshes with the upper flat gear 70 is connected by a connecting shaft 66. Instead of the flat gears 68 and 70, as shown in FIG. (Helical gear) 68A, 70A can be used. In the structure shown in FIG. 11 (b), the rotary shade side helical is arranged so that the thrust force in the axial direction of the connecting shaft 66 acting at the gear meshing portions provided at both ends of the connecting shaft 66 is offset. The directions of the teeth of the gears 62 and 64 and the motor-side helical gears 68A and 70A are taken into consideration, so that the thrust force generated at the gear meshing portion when rotating the rotary shade 34 is used as a load as the output shaft of the motor 58. No effect on 60. In addition, the direction of the teeth of the rotary shade side helical gears 62 and 64 and the motor side helical gears 68A and 70A may be opposite to the tooth direction shown in FIG.

  Further, instead of the upper helical gear 62 and the lower helical gear 64 on the rotary shade 34 constituting the gear train of the driving force transmission mechanism 56 in the present embodiment, as shown in FIG. Alternatively, the lower bevel gear 64A may be used. In the gear train shown in FIG. 11 (c), helical gears 70A and 68A may be used instead of the flat gears 70 and 68. In the gear train shown in FIGS. 11 (a) and 11 (b), the flat gears may be used. Instead of 70 and 68 and helical gears 70A and 68A, bevel gears may be used.

  In the above-described embodiment, only the helical gear 64 on the rotary shade 34 side is made of resin. However, all of the four gears constituting the driving force transmission mechanism 56 and the connecting shaft 66 are also made of resin. In this case, the heat on the side of the rotary shade 34 is more difficult to be transmitted to the motor 58, the temperature rise of the motor can be further suppressed, and the reliability of the motor can be further improved.

  Further, in the above-described embodiment, as shown in FIG. 8E, the light shielding plates 38a and 38f corresponding to the high beams Hi-L and Hi-R have a height that slightly protrudes from the rotating shaft 36. Therefore, the high beams Hi-L and Hi-R in the left light distribution and the right light distribution are formed at the upper end of the light distribution pattern (front illumination area) as shown in the phantom lines in FIGS. 9 (e) and 10 (e). The front end side is cut in a horizontal shape, but by setting the height of the light shielding plates 38a, 38f to 0, for example, the distribution of the high beams Hi-L, Hi-R in the left light distribution and the right light distribution. 9 (e) and 10 (e), the light can be configured in an elliptical shape including a virtual line.

  Further, the rotary shade 34 in the above-described embodiment has a structure in which the light shielding plates 38a to 38f are arranged in the circumferential direction of the rotary shaft 36. However, the present invention is not limited to such a structure. As described in Japanese Patent Laid-Open No. 6-139802 described above, a plurality of light distribution patterns can be formed by rotating a stepped cylindrical body around a horizontal support shaft formed at a position deviated from its axis. In such a configuration, the reflector 26 extends in the direction orthogonal to the optical axis of the light projection unit 14 (the optical axis of the projection lens 28) L in the vicinity of the second focal point of the reflector 26, and is rotatably disposed. The side edge portion in the vicinity may be a light distribution control rotary shade configured to block a part of light traveling from the reflector 26 side toward the projection lens 28 to form a predetermined light distribution pattern.

It is a disassembled perspective view of the light projection unit which is the principal part of the projection type vehicle headlamp which is one Example of this invention. It is a longitudinal cross-sectional view in the optical axis position of the headlamp. It is a side view of the same light projection unit. It is a top view of the same light projection unit which shows a part in section. It is the rear view which removed the reflector from the same light projection unit integrated with the unit frame, and was seen from back. (a) is a figure for demonstrating the change of the height of the wet cam linked with rotation of a rotation shade, (b) is for demonstrating the relationship between a wet cam, a cam follower, and a rotation shade (its light-shielding plate). FIG. 4C is a view showing the structure of the stopper pin and the stopper portion that regulate the rotation range of the rotary shade. It is a figure for demonstrating the relationship between the rotation direction of a rotation shade, and a beam. It is a figure for demonstrating the shape of the light-shielding plate corresponding to a light distribution pattern. It is a figure for demonstrating the irradiation light distribution pattern to a screen. It is a figure for demonstrating the irradiation light distribution pattern to a road surface. (A) is explanatory drawing which shows arrangement | positioning of the gear train of a driving force transmission mechanism (orthogonal transformation mechanism), (b) is explanatory drawing which shows arrangement | positioning of the other Example of the gear train of a driving force transmission mechanism (orthogonal transformation mechanism). (C) is explanatory drawing which shows arrangement | positioning of the further another Example of the gear train of a driving force transmission mechanism (orthogonal transformation mechanism).

Explanation of symbols

L Headlamp irradiation axis (optical axis of light projection unit, optical axis of projection lens)
DESCRIPTION OF SYMBOLS 10 Lamp body 12 Front lens 14 Light projection unit 24 Discharge bulb 26 Reflector 26a Ellipsoidal reflecting surface 28 Projection lens 30 Lens holder 34 Rotation shade 36 Rotating shaft 38a-38f Light-shielding plate 52 Wet cam 56 Driving force transmission mechanism 58 Stepping motor 62, 64 Helical gear 66 Connecting shaft 68, 70 Flat gear 82 Wet shade 84 Swing arm 86 Cam follower 100 Unit frame

Claims (4)

A substantially saddle-shaped reflector; a light source disposed at a substantially first focal point of the reflector; a projection lens disposed in front of the second focal point of the reflector; and the projection in the vicinity of a substantially second focal point of the reflector. It extends in a direction substantially perpendicular to the optical axis of the lens and is rotatably arranged, and its side edge in the vicinity of the optical axis blocks a part of the light from the reflector side toward the projection lens and has a predetermined arrangement. A rotation shade for light distribution control configured to form a light pattern, a motor that generates a driving force for rotating the rotation shade, and a driving force that transmits the driving force of the motor to the rotation shade A projection type automotive headlamp comprising a transmission mechanism, wherein the motor is arranged in a region on a side surface side of the reflector so that an output shaft thereof is orthogonal to the rotary shade. Projection vehicle headlight, characterized and. 2. The projection type automotive headlamp according to claim 1, wherein the driving force transmission mechanism is connected to a driving gear connected to an output shaft of the motor, a driven gear meshing with the driving gear, and the rotary shade. A first orthogonal transformation gear; a second orthogonal transformation gear meshing with the first orthogonal transformation gear; and a connecting shaft that is rotatably supported to connect the driven gear and the second orthogonal transformation gear. A projection-type automotive headlamp comprising: 3. The projection type automotive headlamp according to claim 2, wherein the drive gear, the driven gear, the first orthogonal transformation gear, and the second orthogonal transformation gear are each constituted by a helical gear, and at each gear meshing portion. A projection type automotive headlamp characterized in that the direction of teeth of each helical gear is set so that the thrust forces acting in the axial direction of the connecting shaft are opposite to each other. 4. The projection type automotive headlamp according to claim 1, wherein at least one of a plurality of gears constituting the driving force transmission mechanism is made of a resin. .

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