JP2019003908A - Lamp unit - Google Patents

Abstract

To provide a lamp unit which adjusts a position of a centroid of a rotary shaft, to which a rotary reflector is attached, to a proper position to achieve preferable light scan by the rotary reflector.SOLUTION: A lamp unit LU has a rotary reflector 22 which reflects light emitted from a light source (an LED) 11 while rotating and scans in a predetermined direction. A motor 21 which rotates the rotary reflector 22 includes a stator 24, a rotor 25, and a pair of bearings 26 which are disposed at a spacing from one another in an axial direction of a rotary shaft 211 and support the rotary shaft so that the rotary shaft can rotate around an axis. The rotary reflector 22 and the rotor 25 are attached to the rotary shaft 211, and a centroid G of the rotary shaft 211 is set in an axial space between the pair of bearings 26.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a lamp unit that includes a rotating reflector that reflects light from a light source while rotating a light reflecting blade, and scans the reflected light with the rotating reflector to perform illumination.

  As a lamp unit that constitutes a lamp for a vehicle such as an automobile, particularly a headlamp, there has been proposed a system that performs illumination by scanning light emitted from a light source toward a front area of the vehicle at high speed. Patent Document 1 proposes a technique including a rotating reflector (light reflecting blade) in which a light reflecting surface is configured so that an incident angle of light emitted from a light emitting element continuously changes with rotation. Yes. The incident angle of the light from the light source is changed with the rotation of the rotating reflector, and the reflected angle of the reflected light is changed correspondingly. Therefore, by irradiating the reflected light of the rotating reflector toward the front of the automobile It is possible to scan and illuminate the front area of the vehicle with reflected light.

JP 2017-59546 A

  In the technique of Patent Document 1, a motor is used as a drive source for rotationally driving the rotary reflector. When the rotary reflector is connected to one end of the rotary shaft of the motor, a load along the axial direction is applied to the rotary shaft. The bias is generated. In particular, since the motor is housed in the headlamp together with the rotating reflector, it is preferable to make the motor as small and light as possible in order to reduce the size and weight of the headlamp. However, in the case of a small and light motor, the influence of the weight of the attached rotating reflector is increased, and the position of the center of gravity in the axial direction of the rotating shaft is biased toward one end side where the rotating reflector is attached.

  As described above, when the axial deviation of the center of gravity of the rotating shaft becomes significant, smooth rotation of the rotating shaft is hindered. For example, the rotation axis comes to perform a so-called “slashing movement”. If smooth rotation of the rotating reflector is hindered, an error occurs in the incident angle of light incident on the rotating reflector from the light source, and the intended scan cannot be performed. In addition, a biased force is applied to the bearing that rotatably supports the rotating shaft, and the durability of the motor is reduced due to uneven wear of the bearing.

  An object of the present invention is to provide a lamp unit that adjusts the position of the center of gravity of a rotating shaft to which a rotating reflector is attached to an appropriate position and realizes suitable light scanning by the rotating reflector.

  The present invention is a lamp unit having a rotating reflector that reflects and scans light emitted from a light source while rotating, and a motor that rotates the rotating reflector is attached to a stator and a rotating shaft. A rotor and a pair of bearings spaced apart in the axial direction of the rotating shaft and supporting the rotating shaft so as to be capable of rotating; the rotating reflector and the rotor are attached to one end of the rotating shaft; The center of gravity of the rotating shaft is set between the axial directions of the pair of bearings.

  As a preferred embodiment of the present invention, a balance weight is attached to the other end of the rotating shaft. Further, the length of the other end of the rotating shaft extending from the bearing disposed on the other end side of the rotating shaft is such that one end of the rotating shaft is disposed on the one end side of the rotating shaft. It is made longer than the length extended from the made bearing. Or the bearing arrange | positioned among the pair of bearings at the one end part side of the said rotating shaft is arrange | positioned near the one end part of the said rotating shaft rather than the said stator. Furthermore, the balance weight may be configured as a heat dissipation fan.

  According to the present invention, stable rotation of the rotating shaft is ensured by setting the center of gravity of the rotating shaft of the motor that rotationally drives the rotating reflector between the axial directions of the pair of bearings that support the rotating shaft. The light of the light source can be stably scanned by the rotating reflector.

FIG. 3 is a schematic perspective view of the lamp unit according to the first embodiment. The top view which fractured | ruptured a part of lamp unit of Embodiment 1. FIG. The perspective view which fractured | ruptured a part of reflector part of Embodiment 1. FIG. FIG. 3 is a longitudinal sectional view of a reflector unit according to the first embodiment. The longitudinal cross-sectional view of the reflector part of Embodiment 2. FIG. The longitudinal cross-sectional view of the reflector part of Embodiment 3. FIG. The longitudinal cross-sectional view of the reflector part of Embodiment 4. FIG. The top view which fractured | ruptured a part of lamp unit of Embodiment 4. FIG.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view of Embodiment 1 in which the present invention is configured as a lamp unit LU of a headlamp of an automobile, and FIG. 2 is a plan view with a part thereof broken. The lamp unit LU is configured as a scan type lamp unit capable of adaptively controlling the illumination area and the non-illumination area of the headlamp according to, for example, ADB (Adaptive Driving Beam) light distribution control, that is, the driving situation of the automobile. The light source unit 1, the reflector unit 2, and the projection lens unit 3 are integrally configured as one unit.

  A schematic configuration of the lamp unit LU will be described. The light source unit 1 has a heat sink 12 that is substantially L-shaped in plan view, and an LED (light emitting diode) 11 as a light source is mounted on a part of the inner wall surface of the heat sink 12. The heat sink 12 has a plurality of heat radiation fins 13 formed on a part of its outer surface, and dissipates heat generated when the mounted LED 11 emits light from the heat sink 12 and the heat radiation fins 13 to the external space.

  Although not shown in detail, the LED 11 is configured as a composite LED in which a plurality of LED chips, for example, nine LED chips are arranged in a predetermined shape, and each LED chip emits white light when it emits light. The white light from each LED chip is emitted from the LED 11 as a combined luminous flux. Since nine LED chips are provided to satisfy the luminous intensity required for the lamp unit LU, the number of LED chips may be smaller or larger as long as the required luminous intensity is satisfied. . Moreover, you may be comprised by discrete LED. Furthermore, you may comprise as a LED unit which comprised the condensing lens and the condensing reflector integrally.

  The reflector unit 2 includes a motor 21 and a rotary reflector 22 that is driven to rotate by the motor 21, and is supported by the heat sink 12 by a stem 14. Although details of the motor 21 and the rotary reflector 22 will be described later, the rotary reflector 22 is configured in a substantially disk shape in which two semi-circular light reflecting blades 221 (hereinafter abbreviated as blades) are arranged circumferentially. The center boss 222 is attached to the rotating shaft 211 of the motor 21. Thus, when the motor 21 is driven, the rotary reflector 22 is driven to rotate about the rotary shaft 211.

  The projection lens unit 3 includes a projection lens 31 having a shape obtained by excising a part of a circular lens. The projection lens 31 is supported on the heat sink 12 by a lens holder 32 and a stem 33. As will be described later, the light reflected by the rotating reflector 22 of the reflector unit 2 is projected toward the front of the lamp unit LU. And the front of the car is irradiated. The projection lens 31 leaves only the part necessary for scanning and cuts off other parts, whereby the lens can be downsized or the lamp unit can be downsized and lightened.

  The rotating reflector 22 will be described. FIG. 3 is a perspective view of the reflector portion 2, and is an exploded perspective view in which a part of a casing 23 described later is broken. As described above, two semicircular blades 221 are supported on the boss 222 and are formed in a substantially disk shape as a whole. Each blade 221 has a surface, that is, a surface facing the upper side of FIG. Here, the two blades 221 are integrally formed with the boss 222 by resin molding, and a light reflecting film is formed on at least the surfaces of both the blades 221 by vapor-depositing and plating an aluminum film. A gap extending in the radial direction is provided between the circumferential directions of the two blades 221, and this gap is configured as a non-reflective region that does not reflect light.

  The two blades 221 have a point-symmetric shape with the boss 222 as the center, and the inclination angle in the radial direction of the surface as the light reflecting surface, that is, the inclination angle with respect to the plane perpendicular to the axial direction of the rotating shaft 211 of the motor 21. However, it is set as the structure which changes continuously along the circumferential direction. Here, when the blade 221 is viewed from the front side, the inclination angle is a negative angle inclined to the back side on the clockwise side, and the inclination angle is a positive angle inclined to the front side on the counterclockwise side. ing.

  The lamp unit LU schematically described above is arranged so that the lens optical axis Lx of the projection lens 31 shown in FIG. 2 is directed in the front-rear direction of the automobile when the headlamp is mounted on the automobile. Further, in the LED 11, the outgoing optical axis Ax of the luminous flux emitted from each LED chip is oriented in a direction substantially perpendicular to the horizontal direction with respect to the lens optical axis Lx. The reflector unit 2 is oriented in a direction in which the rotation axis 211 of the motor 21 intersects the outgoing optical axis Ax and the lens optical axis Lx at an angle of approximately 45 degrees in the horizontal direction, and the rotational reflector. The reflection surface of each of the 22 blades 221 is formed so as to pass through the intersection of the emission optical axis Ax and the lens optical axis Lx.

  When the LED 11 emits light, the light emitted from each LED chip is projected onto the surface of the blade 221 of the rotary reflector 22 as a single light beam and reflected there. The reflected light beam is incident on the projection lens 31, and is projected toward the front of the lamp unit LU, that is, the front of the automobile while being refracted here, and irradiates the front area of the automobile.

  The blade 221 of the rotary reflector 22 is rotated by the motor 21, and the position where the light beam from the LED 11 is incident on the surface of the blade 221 changes in the circumferential direction. As described above, since the inclination angle of the surface of the blade 221 changes in the circumferential direction, the incident angle of the incident light beam is changed as the blade 221 rotates. Thereby, the reflection angle of the light beam reflected by the blade 221, that is, the angle in the horizontal direction with respect to the lens optical axis Lx is changed. Therefore, the light beam passing through the projection lens 31 is deflected in the horizontal direction and irradiated while being scanned (scanned) toward the front area of the automobile.

  That is, when the light beam is continuously emitted from the LED 11 over time, the light beam follows the rotation of the rotary reflector 22 and is scanned at a high speed in the horizontal direction S as shown in FIGS. . Since this scanning speed is high, the human eye has a light distribution that illuminates the area scanned in the horizontal direction. Therefore, by controlling the timing of the luminous intensity of the LED 11 (including extinction of zero luminous intensity) in synchronization with this scanning, the horizontal luminous intensity to be scanned can be changed. For example, only a desired area is illuminated, ADB light distribution control that lowers or turns off the light intensity in the region can be realized. Also, by controlling the timing of the light emission intensity of the plurality of LED chips independently, it is possible to realize ADB light distribution control with a finer intensity distribution.

  In the rotary reflector 22, one scan is performed by the rotation of one blade 221. Therefore, in the rotary reflector 22 of this embodiment configured by two blades 221, one rotation of the rotary reflector 22 is performed. Two scans are performed. Since a gap is provided between the two blades 221 in the circumferential direction, when the reflection of light moves from one blade 221 to the other blade 221, light is reflected in this gap. In other words, the light beam is not scanned in the opposite direction during each scan.

  The motor 21 that rotationally drives the rotary reflector 22 will be described. FIG. 4 is a longitudinal sectional view of the reflector section 2. 4 and 3, the motor 21 includes an outer rotor including a stator 24 having a coil (winding) 241 and a rotor 25 having a magnet (permanent magnet) 251 disposed around the stator 24. It is configured as a type brushless motor.

  The motor 21 includes a casing 23 made of hard resin. The casing 23 has a circular container shape with a bottom surface recessed in two steps, and is integrally formed with a hollow cylindrical bearing cylinder 231 protruding from the bottom surface of the casing 23. A pair of radial ball bearings (hereinafter simply referred to as “ball bearings”) 26 are spaced from each other in the cylinder of the bearing cylinder 231 along the cylinder axis direction. A rotating shaft 211 of the motor 21 is inserted in the bearing cylinder 231 and is supported by the pair of ball bearings 26 in the bearing cylinder 231 so as to be rotatable.

  On the inner bottom surface of the casing 23, a circuit board 27 is disposed and supported over a required plane area. The circuit board 27 is composed of, for example, a printed wiring board, and a cylinder portion 271 is integrally provided in a part of the circuit board 27 so as to be positioned on the outer diameter of the bearing cylinder 231. A plurality of coils 241 each having a conducting wire wound around a core are arranged on the peripheral surface of the cylindrical portion 271. Here, six coils 241 are arranged circumferentially. Each coil 241 is electrically connected to a printed wiring (not shown) provided on the circuit board 27 so that power is supplied.

  On the other hand, a rotor yoke 252 having a short cylindrical container shape is attached to the rotating shaft 211 so as to cover the six coils 241 constituting the stator 24. The rotor yoke 252 is made of a ferromagnetic material and is integrally supported in the rotational direction by spline fitting or the like on the rotary shaft 211 at the center of a circular bottom wall. A circumferential wall of the rotor yoke 252 is arranged around the outer periphery of the coil 241, and a plurality of, in this case, four arc-shaped magnets 251 are formed on the inner surface of the circumferential wall with a required pitch dimension in the circumferential direction. Supported in an aligned state. These four magnets 251 are attached so that the N poles and S poles of the surface directed in the inner diameter direction facing the coils 241 are alternately arranged in the circumferential direction.

  The circuit board 27 includes a power supply circuit for supplying power to the coil 241. This power supply circuit performs sequence control on the three-phase signals (U, V, W) that supply power to the six coils 241. In addition, in order to obtain sequence control timing, a plurality of, in this case, three Hall elements 272 for detecting the rotation of the rotor yoke 252 are mounted on the power supply circuit. These Hall elements 272 detect a rotation direction and a rotation speed of the rotor yoke 252 supporting the magnet 251 by detecting a change in the magnetic pole direction of the magnet 251 using the Hall effect. Since the Hall element itself is known, a detailed description thereof is omitted here.

  In this motor, a three-phase signal is fed to six coils, and an N magnetic field or an S magnetic field generated by each coil 241 is changed with time in the circumferential direction, whereby a tangential driving force is generated in each magnet 251. Then, the rotor yoke 252 integrated with the magnet 251 is integrally rotated. The rotation of the rotor yoke 252 causes the attached rotating shaft 211 to rotate, thereby functioning as an outer rotor type motor.

  The boss 222 of the rotary reflector 22 is fitted to one end of the rotary shaft 211, here the end on the side where the rotor yoke 252 is attached, and is integrally attached to the rotary shaft 211. Yes. Thus, when the motor 21 is driven and the rotating shaft 211 rotates, the rotating reflector 22 is rotated, and the light of the LED 11 is reflected as described above by the rotation of the blade 221 to execute illumination by scanning. become.

  As described above, in the embodiment, the rotary reflector 22 and the rotor yoke 252 are respectively attached to one end of the rotary shaft of the motor 21, so that the rotary shaft 211 is pivotally supported when the reflector portion 2 is assembled. After the circuit board 27 is mounted on the casing 23 and the stator 24 is configured, the operation of attaching the rotor yoke 252 to the rotating shaft 211 and attaching the rotating reflector 22 to the rotating shaft 211 can be performed from one side of the casing 23. The motor 21 and the rotating reflector 22 can be easily assembled. In addition, maintenance of the motor 21 and the rotary reflector 22 after the reflector portion 2 is assembled to the heat sink 12 is facilitated.

  On the other hand, when the rotor yoke 252 and the rotary reflector 22 are both attached to one end of the rotating shaft 211, the center of gravity Gx of the rotating shaft 211 is biased toward one end and greatly deviates from the pair of ball bearings 26. It is easy to become a state. For example, as shown in FIG. 4, the center-of-gravity position Gx is a position deviated from one pair of ball bearings 26 to one end side. In such a state, there is a possibility that the rotating shaft 211 may shave along with the rotation of the rotating shaft 211, and the rotation of the rotating reflector 22 may be shaken, and the light of the LED 11 may not be suitably scanned. .

  In Embodiment 1, the balance weight 4 is attached to the other end of the rotating shaft 211, that is, the end opposite to the rotor yoke 252 and the rotating reflector 22 across the casing 23. The balance weight 4 is formed in a columnar shape having a weight substantially equal to the weight of the rotary reflector 22 or a weight close to the combined weight of the rotary reflector 22 and the rotor yaw 252. By attaching the balance weight 4, as shown in FIG. 4, the center of gravity position G of the rotating shaft 211 is set to a position between the axial directions of the pair of ball bearings 26, preferably an intermediate position in the axial direction. Yes.

  By providing the balance weight 4 and positioning the center of gravity G between the pair of ball bearings 26 in this way, when the motor 21 is driven and the rotating shaft 211 rotates, the rotating shaft 211 is misaligned. Suppresses sliding. Therefore, the rotating reflector 22, particularly the two blades 221 attached to one end of the rotating shaft 211, can be stably rotated without causing the rotation center to be shaken, and can reflect the light of the LED 11 stably. Scan is performed.

  In the above embodiment, the balance weight 4 is attached to the other end of the rotating shaft 211 so that the center of gravity of the rotating shaft 211 is positioned between the axial directions of the pair of ball bearings 26. A balance weight is not necessarily required if it can be positioned between the pair of ball bearings 26 in the axial direction.

  FIG. 5 is a longitudinal sectional view of the reflector portion 2 of the second embodiment. In place of the balance weight 4 of the first embodiment, an extension portion 4A that projects the other end of the rotating shaft 211 from the casing 23 to the back side is provided. Yes. That is, the length of the other end of the rotating shaft 211 extending from the bearing 26 (26b) disposed on the other end side is such that one end of the rotating shaft 211 is on one end side of the rotating shaft. An extension 4A is provided so as to be longer than the length extended from the bearing 26 (26a) disposed in

  By providing this extension 4A, the center of gravity G of the rotating shaft 211 is moved to the other end side so that the center of gravity G is positioned between the pair of ball bearings 26 in the axial direction. In this case, although not shown in the drawings, the length of the extension portion 4A can be shortened by configuring a rotating shaft in which the diameter of the extension portion 4A is relatively larger than the one end side portion. .

  FIG. 6 is a longitudinal sectional view of the reflector portion of the third embodiment, in which the protruding length of the bearing cylinder 231 of the casing 23 is increased instead of moving the center of gravity position of the rotating shaft 211 to the other end side, and the bearing cylinder The tip of 231 is made as close as possible to the inner bottom surface of the rotor yoke 252. Then, one end side of the rotating shaft 211 of the pair of ball bearings 26, that is, the ball bearing 26 on the front end side of the bearing cylinder 231 is moved to the front end side so that the one end side is closer to the coil 241 of the stator 24. It is arranged at the position protruding. Accordingly, the distance between the pair of ball bearings 26, that is, the distance between the rotation shaft 211 in the axial direction is increased, and the center of gravity G of the rotation shaft 211 can be positioned between the pair of ball bearings 26.

  On the other hand, the balance weight may be different. FIG. 7 is a longitudinal sectional view of the fourth embodiment. Instead of the balance weight 4 of the first embodiment, the heat radiating fan 5 is attached to the other end of the rotating shaft 211. The heat radiating fan 5 can be used as it is as a cooling fan for various electronic components. In addition, a heat radiating duct 28 that houses the heat radiating fan 5 is provided on the back side of the casing 23.

  The heat radiating duct 28 is formed in a container shape surrounding the heat radiating fan 5 and attached to the back surface of the casing 23. A part of the heat radiating duct 28 is provided with an air inlet 281 at a position facing the heat radiating fan 28. As shown in FIG. 8, the heat radiating duct 28 is extended to a position facing the heat radiating fins 13 of the heat sink 12, and an air supply port 282 is opened at the extended end.

  Since the heat dissipating fan 5 has a predetermined weight, the weight moves the center of gravity G of the rotating shaft 211 to the other end side in the same manner as the balance weight 4 of the first embodiment, and the pair of ball bearings 26 It is possible to set a position between the axial directions of the two. As a result, the rotating shaft 211 is prevented from slashing, the rotating reflector 22 is stably rotated, the light of the LED 11 is appropriately reflected, and a suitable scan is performed.

  Further, when the heat radiating fan 5 is rotated with the rotation of the rotating shaft 211, an air flow is generated in the heat radiating duct 28. Here, air is introduced from the intake port 281 of the heat radiating duct 28, and the introduced air is sent out from the air supply port 282. The sent air is blown toward the heat radiating fins 13 to increase the heat radiation effect in the heat sink 12. Thereby, the heat generated when the LED 11 emits light is efficiently dissipated by the heat sink 12, and the cooling effect of the LED 11 or the lamp unit LU is obtained.

  The heat dissipating duct 28 is not necessarily provided, and the air in the lamp housing in which the lamp unit LU is housed is circulated by rotating the heat dissipating fan 5 to suppress the temperature rise in the lamp housing, or the lamp housing. It is also effective in preventing condensation occurring inside.

  The balance weight in the present invention is not limited to the disk shape described in the embodiment or the heat dissipation fan. Further, the position of the center of gravity can be adjusted as appropriate by configuring so that the position where the weight balance is attached to the rotation shaft can be changed. For example, a screw thread may be formed at the other end of the rotating shaft, and a balance weight may be screwed into the screw thread, thereby changing the screwing position.

  The present invention is not limited to the lamp unit using the brushless motor described in the embodiment. For example, even in a DC motor having a brush, the present invention can be applied when a rotating reflector is attached to one end of a rotating shaft to which a rotor is attached.

  The rotary reflector according to the present invention is not limited to the configuration described in the embodiment, and may be configured in different forms such as the shape and number of blades. For example, the number of blades may be one, or three or more. Further, the configuration of the motor that drives the rotary reflector is not limited to the configuration of the embodiment, and the number of coils and magnets and the phase signal to be driven may be different. Furthermore, it is good also as a structure arrange | positioned in order of the braid | blade, the casing, and the yoke from one edge part of the rotating shaft. Similarly, the light source and projection lens constituting the lamp unit may have different configurations.

LU lamp unit 1 light source part 2 reflector part 3 projection lens part 4 balance weight 4A extension part 5 heat dissipation fan (balance weight)
11 LED (light source)
12 Heat Sink 13 Radiating Fin 21 Motor 22 Rotating Reflector 23 Casing 24 Stator 25 Rotor 26 Ball Bearing (Bearing)
27 Circuit board 28 Radiation duct 211 Rotating shaft 221 Blade 241 Coil 251 Magnet G Center of gravity position

Claims (7)

  A lamp unit that includes a rotating reflector that reflects and scans light emitted from a light source in a predetermined direction while rotating, and a motor that rotates the rotating reflector includes a stator, a rotor attached to a rotating shaft, A pair of bearings spaced apart in the axial direction of the rotating shaft and supporting the rotating shaft so as to be able to rotate; the rotating reflector and the rotor are attached to one end of the rotating shaft; The center of gravity of the lamp unit is set between the axial directions of the pair of bearings.   2. The lamp unit according to claim 1, wherein the rotating reflector includes at least one light reflecting blade, and the light reflecting surface of the light reflecting blade has a configuration in which an opposing angle to the light source is changed along a rotation direction. .   The lamp unit according to claim 1, wherein a balance weight is attached to the other end of the rotating shaft.   The length at which the other end of the rotating shaft extends from a bearing disposed on the other end of the rotating shaft is such that one end of the rotating shaft is on one end of the rotating shaft. The lamp unit according to claim 1, wherein the lamp unit is longer than a length extended from the arranged bearing.   3. The bearing according to claim 1, wherein a bearing disposed on one end side of the rotating shaft among the pair of bearings is disposed closer to one end portion of the rotating shaft than the stator. Lamp unit.   The lamp unit according to claim 3, wherein the balance weight is configured as a heat dissipation fan. The lamp unit according to claim 6, wherein the light source is mounted on a heat sink, and the heat radiating fan is configured to blow an air flow generated by driving to the heat sink.

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