Vehicle lighting

Abstract

The present invention provides a vehicle lighting fixture that, even when installed on the upper part of the vehicle body, effectively illuminates the area immediately in front of the vehicle, while also increasing the design freedom of the lighting fixture and the vehicle, thereby enhancing its aesthetic appeal. [Solution] The lamp unit 4 is equipped on a vehicle to illuminate the road surface immediately in front of the vehicle, and includes a light source (LED) 44 and an illumination lens 45 that projects the light emitted from the light source 44 to provide illumination in a required light distribution pattern. The illumination lens 44 has its lens optical axis Lx oriented horizontally, and the light source 44 is positioned above the lens optical axis Lx with respect to the illumination lens 45 at a required displacement angle. In addition, the light-emitting surface of the light source 44 is tilted forward at a required inclination angle with respect to the lens optical axis Lx and directed toward the illumination lens 44.

Description

Technical Field

[0001] The present invention relates to a vehicle lamp suitable for use in a lamp for illuminating the immediate vicinity of a vehicle during work, which is equipped on a work vehicle such as a tractor.

Background Art

[0002] In work vehicles such as tractors, in addition to the lighting lamps used when traveling on roads, lamps for illuminating the immediate front area and side area of the vehicle during work are provided. Patent Document 1 discloses a configuration in which a side light for illuminating the front of the front wheels is provided at the front part of the tractor body equipped with a headlight. Further, in this Patent Document 1, it is said that by disposing the side light below the headlight, sufficient illuminance in front of the front wheels can be ensured even when using a lamp with low luminous intensity.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] While the technology described in Patent Document 1 is advantageous in ensuring sufficient illumination of the area to be illuminated, the side lights are positioned at the bottom of the vehicle body. As a result, dust and dirt splashed up from the road surface during work can adhere to the surface of the side lights, causing them to become dirty and reducing illumination. It is conceivable to position the side lights at the top of the vehicle body, but if the side lights are positioned higher, it becomes difficult to illuminate the area immediately in front of the vehicle. In other words, if the side lights are positioned at the top of the vehicle body, it is necessary to emit the illumination light downwards at a large angle (depression angle). To increase the depression angle from which the illumination light is emitted, the entire light must be directed downwards, which imposes constraints on the design of the light and tractor, and also creates design challenges such as the appearance of the light and tractor.

[0005] The object of the present invention is to provide a vehicle lighting fixture that can suitably illuminate the area immediately in front of the vehicle even when the lighting fixture is installed on the upper part of the vehicle body, and that enhances the design effect by increasing the degree of freedom in the design of the lighting fixture and the vehicle. [Means for solving the problem]

[0006] The vehicle lighting fixture of the present invention includes a light source and an illumination lens that projects light emitted from the light source to provide illumination in a required light distribution pattern, and is equipped on a vehicle to illuminate the road surface immediately adjacent to the vehicle. The illumination lens has its lens optical axis oriented horizontally, the light source is positioned above the lens optical axis at a required displacement angle with respect to the illumination lens, and its light-emitting surface is tilted forward at a required inclination angle with respect to the lens optical axis and directed towards the illumination lens.

[0007] In this invention, the inclination angle is set so that the light emission axis of the light emitted from the light-emitting surface of the light source is directed toward the lens center of the illumination lens. Furthermore, in this invention, the displacement angle is set based on the relative position between the lens center of the illumination lens and the region center of the illumination area illuminated by the illumination lens.

[0008] In this invention, the illumination lens is a plano-convex lens in which the incident surface into which light from the light source is incident is convex, and the exit surface from which the light is emitted is flat. The convex surface of this illumination lens, which serves as the incident surface, is an aspherical surface designed based on the inclination angle of the light source.

[0009] The vehicle lighting device of the present invention is preferably configured as a work lighting device for a work vehicle, including a tractor. In this case, the lamp unit is preferably configured as a side lamp unit that illuminates an area including the immediate area on the left or right side of the work vehicle, and is preferably housed together with a front lamp unit that illuminates the area in front of the work vehicle in a single lamp housing. Furthermore, it is preferable that the illumination lens of the front lamp unit has a flat emission surface and is arranged side by side with the emission surface of the illumination lens of the side lamp unit. [Effects of the Invention]

[0010] According to the vehicle lighting fixture of the present invention, the illumination lens has its optical axis oriented horizontally, and the light source is positioned above the optical axis of the lens at a required displacement angle relative to the illumination lens. Therefore, the area immediately adjacent to the lighting fixture can be illuminated at a large angle (downward angle) for optimal illumination. Furthermore, since the light-emitting surface of the light source is tilted forward at a required inclination angle relative to the optical axis of the lens and directed toward the illumination lens, the area to be illuminated can be illuminated with uniform brightness. In addition, when the side lamp unit and the front lamp unit are configured as a single unit, it becomes easier to unify the design using the illumination lens, and the degree of freedom when designing the lighting fixture is increased. [Brief explanation of the drawing]

[0011] [Figure 1] A schematic perspective view of a tractor equipped with the lighting fixture (work lamp) of the present invention. [Figure 2] A diagram illustrating the light distribution characteristics of a light fixture mounted on a tractor. [Figure 3] A schematic horizontal cross-sectional view of a work lamp. [Figure 4] A schematic, partially exploded perspective view of a work lamp. [Figure 5]External perspective view of the side lamp unit. [Figure 6] A longitudinal section view along line AA in Figure 5. [Figure 7] A schematic partial exploded perspective view of the side lamp unit. [Figure 8] A perspective view of the inner lens from the rear. [Figure 9] External perspective view of the front lamp unit. [Figure 10] Cross-sectional view along line BB in Figure 9. [Figure 11] A schematic diagram illustrating the configuration of the light source and inner lens of a side lamp unit. [Modes for carrying out the invention]

[0012] Next, embodiments of the present invention will be described with reference to the drawings. Figure 1 is a schematic perspective view of a tractor TR equipped with the lighting device of the present invention, which is configured as a work lamp 1 that illuminates the road surface in the immediate area in front of or to the side of the tractor TR when it is working. The work lamp 1, together with the head lamp 2, is arranged in pairs on the left and right sides of the front of the tractor TR's body, in this case the front of the bonnet. The head lamp 2 is turned on when the tractor TR is driving on a road (public road).

[0013] Figure 1 shows a close-up of the work lamp 1 and headlamp 2 located on the left front of the hood. Since the work lamp 1 and headlamp 2, which are arranged in pairs on the left and right sides respectively, are symmetrical, the following description will focus on the left-side work lamp 1 and headlamp 2.

[0014] The work lamp 1 and headlamp 2 are arranged vertically, with the work lamp 1 positioned above and the headlamp 2 below. As will be described in more detail later, the work lamp 1 includes a front lamp unit 3 and a side lamp unit 4. The headlamp 2 consists of lamps in an existing configuration and includes a high-beam lamp unit 5 and a low-beam lamp unit 6.

[0015] Figure 2 is a schematic light distribution characteristic diagram of the work lamp 1 and the headlamp 2. As also shown in Figure 1, the front lamp unit 3 of the work lamp 1 has a near-front light distribution Nf that illuminates the front area near the tractor TR, and the side lamp unit 4 has a near light distribution Ns that illuminates the area extending from the immediate front to the side of the tractor. The near-front light distribution Nf is formed by combining the light distributions of the left and right front lamp units 3. The near light distribution Ns is formed by the left and right side lamp units 4 respectively.

[0016] Similar to a vehicle such as a passenger car, the headlamp 2 illuminates the front area when traveling on the road. As shown in Figure 2, the high-beam lamp unit 5 has a high-beam light distribution Hi that illuminates a wide front area up to the far front of the tractor TR, and the low-beam lamp unit 6 has a low-beam light distribution Lo that illuminates the front area up to the far side with the oncoming lane side shaded. The low-beam light distribution Lo is formed by the low-beam lamp unit 6, and the high-beam light distribution Hi is formed by the high-beam lamp unit 5 and the low-beam lamp unit 6. Note that the configuration of the headlamp 2 is arbitrary. For example, the high-beam lamp unit and the low-beam lamp unit may be composed of one lamp unit, and the high-beam light distribution and the low-beam light distribution may be switched by selectively blocking a part of the light emitted from this lamp unit.

[0017] Figure 3 is a schematic horizontal cross-sectional view of the work lamp 1, and Figure 4 is a schematic exploded perspective view of the work lamp 1. As also shown in Figure 1, in the work lamp 1, the front lamp unit 3 and the side lamp unit 4 are arranged side by side left and right inside the lamp housing 100. The front lamp unit 3 is arranged on the inner side in the vehicle width direction, and the side lamp unit 4 is arranged on the outer side in the vehicle width direction.

[0018] The lamp housing 100 consists of a container-shaped lamp body 101 with an opening extending from the front to the side of the tractor TR's bonnet, and an outer lens 102 made of a colorless, transparent translucent plate attached to the opening of the lamp body 101. Inside the lamp housing 100, a concealing extension 103 that functions as a pseudo-reflector for aesthetic purposes is provided, and rectangular opening windows 104 and 105 are provided at two locations on the left and right sides of this extension 103. The front lamp unit 3 is provided in the inner opening window 104 in the vehicle width direction, and the side lamp unit 4 is provided in the outer opening window 105.

[0019] The side lamp unit 4 according to the present invention will now be described. Figure 5 is an external view of the side lamp unit 4, and Figure 6 is a longitudinal cross-sectional view of part 5 along line AA. Figure 7 is a schematic exploded perspective view. The side lamp unit 4 includes a bracket 41 that also functions as a heat sink, a light source unit 42 supported on the front surface of the bracket 41, and an inner lens 43 located in front of the light source unit 42 and supported by the bracket 41. The bracket 41 is supported by screws 412 on the inner wall of the lamp body 101 at support pieces 411 provided on both sides. The front surface of the bracket 41 is configured as a surface that is tilted forward at a predetermined angle, as will be described later, and rod-shaped positioning protrusions 413 are formed on the left and right sides of this front surface, each protruding forward for a required length.

[0020] The light source unit 42 is equipped with a rectangular plate-shaped light source substrate 421, and its plate surface is in close contact with the front surface of the bracket 41, so that it is supported by the bracket 41 in a state of being tilted forward at a required angle with respect to the vertical direction. A light-emitting element, in this case one LED (light-emitting diode) 44, which serves as the light source for the front lamp unit 4, is mounted on the tilted front surface of this light source substrate 42. Power is supplied to this LED 44 via a light-emitting circuit not shown in the figure, which is provided on the light source substrate 42. The light-emitting surface of the LED 44 is mounted in a state of being tilted forward along the front surface of the light source substrate 42. A mounting hole 422 is opened in the light source substrate 421, and it is supported by the bracket 41 by a screw 423 inserted through this mounting hole 422. In addition, there is one positioning hole 424 and one screw insertion hole 425 on the left and right sides of the light source substrate 421, respectively.

[0021] The inner lens 43 comprises a lens portion 431 and a support portion 432, which are integrally formed from a light-transmitting material, such as a light-transmitting resin. As shown in Figure 8, a perspective view of the inner lens 43 from the rear, an illumination lens 45, described later, is formed on the rear surface of the lens portion 431. The front surface of the lens portion 431 is formed as a rectangular plane to serve as the light emission surface. This lens portion 431 optically controls the light emitted from the LED 44 using the illumination lens 45, enabling illumination with the near-field light distribution Ns shown in Figure 2.

[0022] The support portion 432 is configured as a rectangular tubular peripheral wall portion that extends backward to surround the lens portion 431 on all sides (top, bottom, left, and right). The lower and upper walls of the support portion 432 are longer than the upper wall portion and extend backward towards the lamp, corresponding to the forward tilt of the front surface of the bracket 41. The rear ends of both the left and right walls are inclined to correspond to the lower and upper walls, and each has a pair of support pieces 433 that protrude in the left and right directions. Each support piece 433 has a positioning hole 434 and a screw insertion hole 435, which correspond to the positioning hole 424 and screw insertion hole 425 provided in the light source substrate 421.

[0023] When assembling the side lamp unit 4, the light source unit 42 and the inner lens 43 are placed on top of each other on the front surface of the bracket 41. At this time, the positioning projections 413 of the bracket 41 are inserted through the positioning holes 424 of the light source unit 42 and the positioning holes 434 of the inner lens 43, thereby positioning the light source unit 42 and the inner lens 43 in the planar direction with respect to the bracket 41. Then, the screws 414 are inserted through the screw insertion holes 435 and 425 and screwed into the bracket 41, thereby supporting the inner lens 43 and the light source unit 42 on the bracket 41. This completes the assembly of the side lamp unit 4. In the assembled state, the light source unit 42 is sandwiched between the inner lens 43 and the bracket 41, and their front-to-back positioning is achieved.

[0024] As shown in Figure 5, the assembled side lamp unit 4 is installed inside the lamp housing 100 by the bracket 41 being supported on the lamp body 101 by screws 412. In this installed state, the light-emitting surface of the lens portion 431 of the inner lens 43 is directed forward of the work lamp 1 through the opening window 105 that is opened in the extension 103. More precisely, it is directed outward in the vehicle width direction by a required angle relative to the front direction of the tractor TR.

[0025] Next, the front lamp unit 3 will be described. Figure 9 is an external view of the front lamp unit 3, and Figure 10 is a cross-sectional view along line BB in Figure 9. The front lamp unit 3 has the same basic configuration as the side lamp unit 4, and is composed of a bracket 31 that functions as a heat sink, a light source unit 32 supported on the front of the bracket 31, and an inner lens 33 positioned in front of the light source unit 32.

[0026] The bracket 31 is supported by screws 312 at support pieces 311 provided above and below it on the inner wall of the lamp body 101. The light source unit 32 includes a light source substrate 321, on which an LED 35 is mounted, and is supported by the front of the bracket 31. The inner lens 33 includes a lens portion 331 and a support portion 332, and is supported by the bracket 31 by screws 314 at support pieces 333 provided above and below the support portion 332, so as to sandwich the light source unit 32. When the light source unit 32 and the inner lens 33 are supported by the bracket 31, the positioning projection 313 provided on the bracket 31 positions the light source unit 32 and the inner lens 33 in the planar direction. In addition, the light source unit 32 is sandwiched between the bracket 31 and the inner lens 33, thereby positioning them in the front-to-back direction.

[0027] The front lamp unit 3 shares a common configuration with the side lamp unit 4, but differs in that the front surface of the bracket 31 is oriented vertically, and the front surface of the light source substrate 321 is also oriented vertically. Furthermore, two LEDs 34 are mounted on the front surface of the light source substrate 321 at a required distance apart in the left-right direction, with their light-emitting surfaces facing forward, to serve as the light source for the front lamp unit 3. The lens portion 31 of the inner lens 33 has two illumination lenses 35 on its rear surface, corresponding to the two LEDs 34.

[0028] As shown in Figure 10, the two illumination lenses 35 of the inner lens 33 are each positioned opposite two LEDs 34, and the light emitted from each LED 34 is illuminated by the near-forward light distribution Nf shown in Figure 2. In this embodiment, the illumination lenses 35 are configured as TIR (Total Internal Reflection) lenses, each having the required optical steps formed on the rear light incident surface facing the LEDs 34. This configuration efficiently receives the light emitted from the LEDs 34 and efficiently emits it towards the required area through internal reflection. Although not shown in the figures, each LED 34 is positioned slightly above the lens optical axis of the corresponding illumination lens 35, so that the light emitted from the illumination lens 35 is directed downward from the lens optical axis.

[0029] The front surface of the lens portion 331, which serves as the light-emitting surface, is formed as a single rectangular plane including two illumination lenses 35. When the front lamp unit 3 is supported by the lamp body 101, the light-emitting surface of the lens portion 331 is exposed to the front of the work lamp 1 through the opening window 104 of the extension 103. As a result, when the work lamp 1 is viewed from the front, the rectangular lens portions 32 and 42 of the front lamp unit 3 and the side lamp unit 4 appear side by side, creating a unified design and enhancing the aesthetic appeal of the work lamp.

[0030] With the work lamp 1 configured as described above, when the tractor TR is working, the LEDs 34 and 44 of the light sources 32 and 42 of the front lamp unit 3 and the side lamp unit 4 are powered and emit light. The light emitted from each LED 34 and 44 is incident on the corresponding inner lenses 33 and 43, and is emitted from the light-emitting surfaces of the respective lens parts 32 and 42, thereby illuminating the area from the front to the side of the tractor TR with the near-forward light distribution Nf and the very near light distribution Ns shown in Figure 2.

[0031] Here, the side lamp unit 4 is required to illuminate the area immediately in front of the tractor TR more than the front lamp unit 3. In particular, in this embodiment, since the work lamp 1 is located on the top of the tractor TR's bonnet, the side lamp unit 4 is required to direct the illumination light downwards at a larger angle than the front lamp unit 3. On the other hand, as mentioned above, the side lamp unit 4 is required to enhance the design freedom and aesthetic effect when designing the work lamp 1. In the side lamp unit 4 of this embodiment, the light source unit 42 and the inner lens 43 are configured to satisfy these requirements.

[0032] Specifically, Figure 11 shows a schematic diagram of the light source section 42 and inner lens 43 of the side lamp unit 4. The illumination lens 45 of the inner lens 43 is based on a plano-convex lens with a flat front surface and a spherical rear surface, and its optical axis Lx is oriented horizontally. The LED 44 is positioned above the optical axis Lx, and is set at a required displacement angle θ1 with respect to the optical axis Lx, with respect to the lens center LO of the illumination lens 45 as the reference point. Here, the lens center LO is, for example, the principal point of the illumination lens 45 (the intersection point of the principal plane and the optical axis of the lens). In the case of an illumination lens 45 with a front principal point and a rear principal point, it is the rear principal point opposite the LED 44.

[0033] The displacement angle θ1 can be set, for example, by a geometric method involving the height H1 from the road surface of the lens center LO or lens optical axis Lx of the illumination lens 45, and the horizontal distance L1 from the lens center LO (front principal point) of the illumination lens 45 to the region center C of the illumination area of ​​the immediate light distribution Ns. In other words, it is set by the relative position between the center LO of the illumination lens 45 and the region center C of the illumination area. This makes it possible to illuminate a predetermined range of area centered on a predetermined position immediately in front of or to the side of the tractor TR for the immediate light distribution Ns.

[0034] Furthermore, the light-emitting surface of the LED 44 is tilted forward at a required inclination angle θ2 with respect to the lens optical axis Lx. This inclination angle θ2 is set to the angle at which the light emitted from the light-emitting surface of the LED 44 is efficiently incident on the illumination lens 45. In other words, in order to make the brightness of the illumination area of ​​the immediate light distribution Ns uniform, it is preferable to set the inclination angle θ2 of the light-emitting surface of the LED 44 to 0 degrees, which is an angle parallel to the road surface. However, this reduces the efficiency of the light emitted from the light-emitting surface being incident on the illumination lens 45, and thus reduces the brightness. Therefore, for example, when the central axis of the light emitted from the light-emitting surface of the LED 44 is taken as the light emission axis, in other words, when the normal axis passing through the center of the light-emitting surface is taken as the light emission axis, this light emission axis is set to be directed towards the lens center LO (rear principal point) of the illumination lens 45. Thus, it can also be said that the inclination angle θ2 is θ2 = 90 (degrees) - θ1. As a result, the luminous beam (bulb of light rays) within a required solid angle range centered on the light emission axis emitted from the light-emitting surface of the LED 44 is incident on the illumination lens 45, thereby increasing the light efficiency.

[0035] On the other hand, since the inclination angle θ2 is not 0 degrees, there are limitations to illuminating the illumination area with uniform brightness. Therefore, in this embodiment, the convex surface of the illumination lens 45 is designed to be aspherical using methods such as ray tracing. That is, the light-emitting surface of the LED 45 is designed to be aspherical so that it is projected parallel to the road surface of the illumination area. As a result, the light emitted from the light-emitting surface of the LED 45 is uniformly illuminating almost the entire illumination area with the nearest light distribution Ns, making it possible to illuminate the illumination area with uniform brightness.

[0036] As described above, even when the work lamp 1 of this embodiment is installed on the upper part of the tractor TR's body, it is possible to emit illumination light downwards at a large downward angle, illuminating the road surface in the immediate front or lateral area of ​​the tractor TR. In particular, the lateral lamp unit 4 can illuminate the immediate left and right areas. This makes it possible to suppress the soiling of the work lamp 1 that occurs when the work lamp 1 is installed on the lower part of the vehicle body, and a highly reliable work lamp can be constructed. Furthermore, it is not necessary to tilt the entire work lamp 1 downwards so that the light-emitting surface of the work lamp 1 faces downwards, which increases the degree of freedom when designing the work lamp 1 or the tractor TR.

[0037] Furthermore, since the front surfaces of the lens portions 331 and 431 of the inner lenses 33 and 43 of the front lamp unit 3 and the side lamp unit 4 that constitute the work lamp 1 are formed as vertically oriented planes, the front lamp unit 3 and the side lamp unit 4 each have the appearance of rectangular flat surfaces, achieving design uniformity and enhancing the aesthetic appeal of the work lamp.

[0038] Simultaneously, since the lens portions 331 and 431 of both lamp units do not protrude forward from the opening windows 104 and 105 of the extension 103, the distance between the lens portions 321 and 421 of each inner lens 32 and 42 and the outer lens 102 can be reduced. This reduces the front-to-back dimensions of the work lamp 1, making it possible to make the lamp thinner, and also makes it easier to increase the downward angle when illuminating the immediate vicinity.

[0039] The above embodiment is an example of application to a tractor's work lamp, but it is not limited to the type of vehicle or lamp application as long as it is a lamp that requires illuminating the area immediately in front of the vehicle at a large angle (downward angle). [Explanation of Symbols]

[0040] 1 Work Lamp 2 Headlights 3. Front lamp unit 4. Side lamp unit 5. High beam lamp unit 6. Low beam lamp unit 31,41 bracket 32,42 Light source section 33,43 Inner Lens 34,45 LED (light source) 35, 45 Irradiation lens 100 Lamp Housing 101 Lamp Body 102 Outer Lens 103 Extension 104,105 Opening windows 331,431 Lens section 332,432 Support part TR Tractor (vehicle) Lx lens optical axis LO Lens center (principal point) Center of illumination area C θ1 Displacement angle θ2 Tilt angle

Claims

1. A lighting device for a vehicle, comprising a light source and an illumination lens that projects light emitted from the light source to provide illumination in a required light distribution pattern, wherein the lamp unit is mounted on a vehicle to illuminate the road surface immediately adjacent to the vehicle, characterized in that the optical axis of the illumination lens is oriented horizontally, the light source is positioned above the optical axis of the illumination lens at a required displacement angle, and the light-emitting surface of the light source is tilted forward at a required inclination angle with respect to the optical axis of the lens and directed toward the illumination lens.

2. The vehicle lamp according to claim 1, wherein the inclination angle is set such that the light emission axis of the light emitted from the light-emitting surface of the light source is directed toward the lens center of the illumination lens.

3. The vehicle light fixture according to claim 1, wherein the displacement angle is set based on the relative position between the lens center of the illumination lens and the region center of the illumination area illuminated by the illumination lens.

4. The vehicle light fixture according to claim 2, wherein the illumination lens is a plano-convex lens in which the incident surface into which the light from the light source is incident is convex and the outgoing surface from which the light is emitted is flat.

5. The vehicle lighting device according to claim 4, wherein the convex surface of the illumination lens as the incident surface is an aspherical surface designed based on the inclination angle of the light source.

6. A vehicle light according to claims 1 to 5, wherein the vehicle light is configured as a work light for a work vehicle including a tractor.

7. The vehicle lighting fixture according to claim 6, wherein the lamp unit is configured as a side lamp unit that illuminates an area including the immediate area on the left or right side of the work vehicle, and is housed together with a front lamp unit that illuminates the area in front of the work vehicle in a single lamp housing.

8. The vehicle lamp according to claim 7, wherein the front lamp unit comprises a light source and an illumination lens that emits light from the light source from an emission surface, and the illumination lens of the front lamp unit has an emission surface formed on a flat surface and is arranged side by side with the emission surface of the illumination lens of the side lamp unit.

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