Snow melting heater unit

Abstract

To provide a snow-melting heater unit that is included in a vehicular lighting fixture and properly switches temperature.SOLUTION: A snow-melting heater unit included in a vehicular lighting fixture includes: a heat generating member for generating heat by being supplied with power; a temperature sensor; a control unit for controlling power supply to the heat generating member on the basis of a measured value by the temperature sensor; and a connection cord connected to a power supply and the control unit to supply power. The control unit is disposed inside or outside the lamp chamber. The connection cord is disposed while being exposed at least partially to the outside of the lamp chamber. The temperature sensor is installed in the exposed part. The temperature sensor is disposed outside the lamp chamber, whereby the snow-melting heater unit operates without being influenced by rise of internal temperature of the lamp chamber.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a snow melting heater unit provided in a vehicle lamp.

Background Art

[0002] Snow adhering to the lamp cover of a vehicle lamp hinders appropriate light irradiation. To melt the snow on the lamp cover, some vehicle lamps have a snow melting function.

[0003] The snow melting function is implemented by a heating member that generates heat by supplying power. The heat of the heating member that generates heat melts the snow adhering to the lamp cover. The heating member is controlled to operate according to the ambient temperature detected by a temperature sensor. To ensure the operation of the snow melting function, the temperature sensor is arranged near the lamp cover.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the snow melting function is specified to turn on at low temperatures and turn off at high temperatures, in Patent Document 1, there is a problem that the temperature sensor detects the temperature rise due to the lighting of the lamp light source arranged in the lamp chamber or the heat generation of the heating member, and the snow melting function accidentally turns off.

[0006] For example, if the snow melting function is designed to turn on when the ambient temperature is 5 degrees Celsius and off when it rises to 15 degrees Celsius, the snow melting function will turn on when the temperature inside the lamp chamber drops to 5 degrees Celsius. However, if the temperature inside the lamp chamber rises to 15 degrees Celsius due to heat generated by the lamp light source and heating components, the snow melting function will turn off even if the ambient temperature is 5 degrees Celsius. As the snow melting function turns off, the temperature inside the lamp chamber will drop, and eventually when it reaches 5 degrees Celsius, the snow melting function will turn on again. In this way, the snow melting function will repeatedly turn on and off.

[0007] This invention was made in view of the above problems, and provides a snow melting heater unit that appropriately switches between ON and OFF based on temperature. [Means for solving the problem]

[0008] To solve the above problems, the snow melting heater unit provided in the vehicle lighting fixture of this disclosure comprises a heating element that generates heat when power is supplied, a temperature sensor, a control unit that controls the power supply to the heating element based on the measured value of the temperature sensor, and a power supply and a connecting cord connected to the control unit to supply power. The control unit is located inside or outside the lighting fixture, and at least a portion of the connecting cord is exposed outside the lighting fixture, with the temperature sensor provided on the portion of the connecting cord exposed outside the lighting fixture.

[0009] According to this configuration, the temperature sensor can be placed outside the lamp chamber, allowing the outside temperature to be measured independently of the temperature inside the lamp chamber, and enabling the snow melting function to be switched on and off appropriately.

[0010] In one embodiment, the connecting cord is configured to be selectively connected to either a vehicle power supply or a lighting power supply to provide power.

[0011] In one embodiment, the connecting cord is provided with a power connector at its end, and is configured to be selectively connected to either the vehicle power supply or the lighting power supply by connecting either a power cable connected to the vehicle power supply or a cap that short-circuits the circuit of the power connector to the power connector.

[0012] In one embodiment, the control unit is configured to supply power to the heat-generating element for a predetermined period of time when power supply to the control unit is initiated. [Effects of the Invention]

[0013] As is clear from the above explanation, we can provide a snow melting heater unit that appropriately switches between ON and OFF based on temperature. [Brief explanation of the drawing]

[0014] [Figure 1] This is a perspective view of a vehicle light fixture according to the first embodiment. [Figure 2] This is a front view illustrating the general configuration of the lighting equipment for the vehicle. [Figure 3] This is a cross-sectional view along line III-III in Figure 2. [Figure 4] This shows the first power supply configuration in which the snow melting heater unit is powered by the vehicle battery. [Figure 5] This shows a second power supply configuration in which the snow melting heater unit is powered by the lighting fixture's power supply. [Figure 6] This is a cross-sectional view of a modified vehicle light fixture. It corresponds to Figure 3. [Modes for carrying out the invention]

[0015] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The embodiments are illustrative rather than restrictive, and not all features or combinations thereof described in the embodiments are necessarily essential to the invention. Also, in the descriptions of the following embodiments and modifications, the same components are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. Note that in each figure, the dimensions and ratios do not reflect actual numerical values but schematically represent the configuration.

[0016] (First Embodiment) FIG. 1 is a perspective view of a vehicle lamp 1 according to the first embodiment. FIG. 2 is a front view showing the schematic configuration of the vehicle lamp 1.

[0017] The vehicle lamp 1 is a rear combination lamp including four lamps: a tail lamp, a turn signal lamp, a stop lamp, and a back lamp, and is disposed in a pair on the left and right at the rear end of the vehicle. In the vehicle lamp 1, with the light-emitting surface facing the front of the vehicle lamp 1 as a reference, each direction is described. When the vehicle lamp 1 is installed on the vehicle, it is rotated 180 degrees and mounted on the vehicle body.

[0018] The vehicle lamp 1 includes, as a lamp housing, a lamp body 2 and a lamp cover 4. The lamp body 2 is a housing with an open front, and a lamp chamber S is formed inside by attaching the lamp cover 4 to the opening. The lamp cover 4 is a so-called outer cover and is a substantially transparent lens formed of a light-transmissive resin such as polycarbonate. Without being limited to this, the lamp cover 4 may have an optical step formed thereon for diverging and diffusing the light emitted from the light source when each lamp is lit.

[0019] In the drawn lamp chamber S, four lamp units LU1 to LU4 are accommodated. The four lamp units LU1 to LU4 are respectively a tail lamp unit, a turn signal lamp unit, a stop lamp unit, and a back lamp unit. Hereinafter, unless specifically designating one lamp unit, these lamp units are collectively referred to as lamp unit LU. Each lamp unit LU irradiates the light emitted from the light source forward to form respective lamp light distributions in front of the lamp fixture. Each lamp unit LU uses a conventionally well-known configuration, such as a reflector type or a projector type lamp fixture unit, regardless of its type. As the light source used for each lamp unit LU, a light-emitting element that does not generate heat, such as an LED (Light Emitting Diode), an LD (Laser Diode), or an EL (Electro Luminescence) element, is used.

[0020] On the inner surface of the lamp cover 4, a heating member 6 that generates heat when powered is laid. The heating member 6 is linearly configured and laid on a film-like transparent member serving as a base in a predetermined wiring pattern, and is attached to substantially the entire surface of the lamp cover 4. Due to the heat generated by the heating member 6, the snow and ice adhering to the outer surface of the lamp cover 4 are melted, and the fog generated inside and outside is eliminated, ensuring appropriate light distribution of each lamp unit.

[0021] The heating element 6, for example, is a resistive heating element, which is laid on the inner surface of the lamp cover 4 in a desired circuit pattern. The resistive heating element is composed of a material with relatively low conductivity, such as tungsten, molybdenum, or nickel-chromium. Power is supplied to the resistive heating element, causing it to be resistively heated, thereby raising its temperature to a level where it can melt snow. Since the resistive heating element is long and thin, the reduction in the light transmission of the lamp cover 4 due to the laying of the resistive heating element on the lamp cover is kept within an acceptable range. In this embodiment, the heating element 6 is laid in a pattern that is almost parallel and continuous, meandering in a zigzag pattern from left to right. The laying pattern of the heating element 6 is not limited to this, and it is sufficient if it is laid comprehensively in the light-transmitting area of ​​the lamp cover 4, mainly in front of each lamp unit. The heating element 6 may be laid by transfer or screen printing, or it may be laid directly on the lamp cover 4.

[0022] The heating element 6 is not limited to the above, as long as it is a heating element that generates heat while ensuring the light transmittance of the lamp cover 4. It may also be a transparent heating element made of an ITO film (indium tin oxide film) or a film heater such as an FPC using conductive ink on a transparent film.

[0023] Furthermore, since the heating element 6 is provided for the implementation of the snow-melting function of the vehicle light fixture 1, it is not limited to being provided on the lamp cover 4, such as by applying conductive silver paste to the lamp cover 4 or by attaching it as a film. For example, a linear heating element 6 may be laid on the inner lens, and this inner lens may be positioned near the lamp cover 4 to melt the snow accumulated on the lamp cover 4.

[0024] Electrical contacts 20 are formed at the end portions of the heating element 6, which are the starting and ending points. The electrical contacts 20 are power supply ports for the heating element 6, and the heating element 6 is powered via the electrical contacts 20.

[0025] A power supply unit 30 is provided inside the lamp body 2 as a mechanism for supplying power to the heating element 6 by being electrically connected to the electrical contact 20. The power supply unit 30 is directly or indirectly connected to the vehicle power supply, and the heating element 6 is powered via the power supply unit 30 when the power supply unit 30 and the electrical contact 20 are electrically connected.

[0026] The power supply unit 30 has elastically deformable connection terminals, such as pogo pins or spring terminals, and is positioned opposite the electrical contacts 20 provided on the inner surface of the lamp cover 4. The connection terminals are biased and protrude toward the front of the lamp cover 4. During the assembly process of the vehicle lighting fixture 1, when the lamp cover 4 and the lamp body 2 are positioned opposite each other and welded together, the connection terminals come into contact with the electrical contacts 20 while biased, and are electrically connected to the electrical contacts 20. Since the connection terminals and the electrical contacts 20 are electrically connected naturally during the assembly process, there is no need for a separate process to electrically connect them, and because the electrical contacts 20 and the connection terminals are electrically connected while biased, the electrical connection is stable.

[0027] The method of electrical connection and power supply from the power supply unit 30 provided on the lamp body 2 to the heat-generating element 6 provided on the lamp cover 4 is not limited to this, and known methods such as using a floating connector or connecting connectors outside the lamp chamber or after welding the lamp body may also be used.

[0028] (Snow melting heater unit) Figure 3 is a cross-sectional view taken along the line III-III in Figure 2. The vehicle light fixture 1 has a snow-melting function, which is implemented by a snow-melting heater unit 7. As shown in Figure 3, the light chamber S, formed by the lamp body 2 and the lamp cover 4, mainly houses the lamp unit LU and a portion of the snow-melting heater unit 7. The snow melting heater unit 7 comprises the aforementioned heating element 6, snow melting heater control unit 40, temperature sensor 8, and connection cord C connecting these. The connection cord C mainly consists of connecting wires for electrically connecting multiple devices.

[0029] The heating element 6 is laid on the inner surface of the lamp cover 4 and is powered via the power supply unit 30. The power supply unit 30 is located near the opening of the lamp body 2 and is connected to the snow melting heater control unit 40 by a connecting cord C.

[0030] The snow melting heater control unit 40 consists of electronic equipment mounted on a circuit board 41 and is fixed to the inner back surface 2a of the lamp body 2 by a fixing member (not shown). The snow melting heater control unit 40 is a microcontroller equipped with at least one processor (e.g., CPU) and at least one memory (e.g., DRAM), and primarily controls the power supply to the heat generating element 6.

[0031] The temperature sensor 8 is a thermistor that measures temperature by utilizing the change in resistance when heat is detected. The temperature sensor 8 is not limited to this; thermocouples, transistors, diodes, etc., may also be used.

[0032] An opening 2b is provided on the back of the lamp body 2 for inserting the connecting cord C, and one end of the branched portion of the connecting cord C is inserted through the opening 2b and positioned outside the lamp chamber S.

[0033] A temperature sensor 8 and a power connector 50 are provided at the end of the portion of the connection cord C that is exposed outside the lamp chamber S. The opening 2b is covered from the outside of the lamp body 2 by a back cover 3 which is formed in the shape of a box with an open front, and the power connector 50 and temperature sensor 8 are exposed outside the lamp chamber S and are located inside the back cover 3.

[0034] The temperature sensor 8 outputs its readings to the snow melting heater control unit 40. Based on the readings from the temperature sensor 8, the snow melting heater control unit 40 decides whether to supply or disconnect power to the heating element 6. Since the heating element 6 implements the snow melting function, the snow melting heater control unit 40 decides whether to turn the snow melting function of the vehicle light fixture 1 ON or OFF.

[0035] Regarding the power supply to the heat-generating element 6, a starting temperature T1 for starting the power supply and an upper limit temperature T2 for discontinuing the power supply are provided. For example, if the starting temperature T1 is 5 degrees and the upper limit temperature T2 is 15 degrees, then when the temperature sensor 8 measures 5 degrees or less, the power supply to the heat-generating element 6 will start, and when the temperature sensor 8 measures 15 degrees or more, the power supply to the heat-generating element 6 will be discontinued.

[0036] The temperature sensor 8 is located outside the lamp chamber S. Conventionally, when the snow melting function is switched ON / OFF by temperature, the temperature sensor is located near the lamp cover or in contact with the lamp cover. This is to measure the temperature of the lamp cover, which is the object heated by the snow melting function, more precisely. When the temperature of the lamp cover drops to a temperature at which snow accumulation or fogging is a concern, the snow melting function is turned ON. Then, when the temperature rises to a predetermined value, there is no longer any concern about fogging of the lamp cover, and the snow melting function is deemed unnecessary and is turned OFF. When the upper limit temperature T2 is reached, the power supply to the heating element 6 is cut off, and the snow melting function is turned OFF. This also serves as a safety device to prevent malfunctions such as burnout of the heating element or wires due to forgetting to turn it off.

[0037] However, on the other hand, if the temperature sensor is placed near the lamp cover, there was a problem in that the temperature sensor would detect the temperature rise caused by the lighting of the lamp light source or the heat generated by the heating element inside the lamp chamber, causing the snow melting function to turn off automatically. For example, if the snow melting function is designed to turn on when the ambient temperature is 5 degrees and then turn off when it rises to 15 degrees, the snow melting function will turn on when the lamp chamber temperature drops to 5 degrees, and then turn off when the lamp chamber temperature rises to 15 degrees due to the heat generated by the lamp light source and heating element, even if the outside temperature is 5 degrees. Since the snow melting function is turned off, the lamp chamber temperature will drop, and when the lamp chamber temperature drops to 5 degrees, the snow melting function will turn on again. Even if the outside temperature does not change, the measured temperature fluctuates, causing the snow melting function to repeatedly turn on and off, and in some cases it may not be able to perform properly.

[0038] Therefore, in the vehicle lighting fixture 1, the temperature sensor 8 is placed outside the lighting chamber S, and the power supply / disconnection of the heating element 6 can be switched based on a more accurate ambient temperature.

[0039] Furthermore, because the snow-melting heater unit 7 includes a temperature sensor 8 and a snow-melting heater control unit 40, the vehicle light fixture 1 can independently control its snow-melting function. In other words, instead of acquiring temperature information from a temperature sensor mounted on the vehicle, the snow-melting heater unit 7 is equipped with a temperature sensor 8 and includes a snow-melting heater control unit 40 that controls the power supply to the heating element 6 based on the measurement value of the temperature sensor 8. Therefore, by simply replacing the vehicle light fixture 1 and supplying power, the vehicle light fixture can be given a snow-melting function. Conventionally, vehicle light fixtures and snow-melting functions were separate products, such as attaching a film heater as a heating element to the vehicle light fixture. Moreover, the specifications required acquiring information from the vehicle's temperature sensor to switch the snow-melting function ON / OFF. In contrast, the vehicle light fixture 1 has a specification that integrates the light fixture and snow-melting function independently. The vehicle and the light fixture are connected by a connection cord C, and the snow-melting function operates independently simply by supplying power from the vehicle side. When the temperature sensor 8's reading drops to the starting temperature T1, power is supplied to the heating element 6. When the temperature rises to the upper limit temperature T2, the power supply to the heating element 6 is cut off. This is done independently of the vehicle's control system. The vehicle lighting fixture 1 is configured to operate as a vehicle lighting fixture with snow-melting function simply by being connected to a power source, regardless of the vehicle's specifications.

[0040] (Power supply) The power supply to the snow melting heater unit 7 will be explained in detail. The snow melting heater unit 7 has two power supply modes: a first power supply mode in which power is supplied directly from the vehicle battery VB, which is the vehicle's power source, and a second power supply mode in which power is supplied from a predetermined lighting power source (in this embodiment, the power supply circuit for the taillights). The two power supply modes will be explained using Figures 4 and 5.

[0041] Figure 4 is an explanatory diagram of the first power supply configuration. Figure 4(A) is a cross-sectional view of the vehicle lighting device 1 in the first power supply configuration. Figure 4(B) is a wiring diagram of the first power supply configuration.

[0042] As mentioned above, the connection cord C is an assembly consisting mainly of wires that connect components and has multiple branch sections. The power supply section 30, temperature sensor 8, power connector 50, snow melting heater control section 40, and lamp unit circuit 71 are connected to or provided at each of the multiple ends of the connection cord C.

[0043] In the first power supply configuration, that is, when the vehicle battery VB and the snow melting heater unit 7 are directly connected and the snow melting heater unit 7 is powered by the vehicle battery VB, the power connector 50 is connected to the power cable 60 that is connected to the vehicle battery VB.

[0044] The power cable 60 has one end connected to the vehicle battery VB and the other end is provided with a connector 61. By connecting the connector 61 to the power connector 50, the snow melting heater unit 7 is supplied with power directly from the vehicle battery VB.

[0045] As shown in Figure 4(B), in addition to the snow melting heater control unit 40, a lamp unit control unit 70 that controls the on / off switching of the lamp unit LU is located inside the lamp chamber S. The connection cord C of the snow melting heater unit 7 is connected to one of the power supply circuits of the lamp unit LU (in this embodiment, the power supply and ground for the tail lamp). The power cable 60 is equipped with a relay 62 and a fuse 63. When it receives an electrical signal from the circuit of the lamp unit LU, the relay 62 turns ON, and the snow melting heater unit 7 is connected to the vehicle battery VB, and power is supplied directly from the vehicle battery VB.

[0046] Figure 5 is an explanatory diagram of the second power supply configuration. Figure 5(A) is a cross-sectional view of the vehicle lighting fixture 1 in the second power supply configuration. Figure 5(B) is a wiring diagram of the second power supply configuration.

[0047] As shown in Figure 5, in the second power supply configuration in which the snow melting heater unit 7 is powered from the lamp power supply (in this embodiment, the tail lamp power supply), a short-circuit cap 80 is connected to the power connector 50. The short-circuit cap 80 has a short-circuit wire 81, which short-circuits two circuit wires connected to the power connector 50. Since the power connector 50 is connected to a branch line from the tail lamp power supply and a connection line to the snow melting heater control unit 40, when the two are connected by the short-circuit wire 81, the snow melting heater unit 7 is connected to the tail lamp power supply circuit and powered from the lamp power supply.

[0048] The first and second power supply configurations are determined by whether the power cable 60 or the short-circuit cap 80 is connected to the power connector 50. Depending on which is connected to the power connector 50, the power source for the snow melting heater unit 7 is selectively selected to be either the vehicle battery VB or the power circuit of the lamp unit LU.

[0049] In the second power supply configuration, the snow melting heater unit 7 is powered by the power supply circuit of the lamp unit LU, and operates as a lamp with a snow melting heater when the temperature sensor 8 reaches the starting temperature T1, in conjunction with the connected lamp unit LU (tail lamp in this embodiment).

[0050] In the past, when supplying power to a snow-melting heater unit, depending on the vehicle specifications, there was a problem that the current capacity of the power supply from the lamp unit was insufficient. In such cases, the vehicle lighting device 1 can solve this problem by supplying power from the vehicle battery VB by connecting the power cable 60 to the power connector 50 as a first power supply method.

[0051] Furthermore, conventionally, specifications for power supply from the lamp unit and specifications for power supply from the vehicle battery were different, with different specifications for circuits, connection cords, lamp units, etc. In the vehicle lighting fixture 1, the power source for the snow melting heater unit 7 can be changed simply by swapping the power cable 60 / short-circuit cap 80 connected to the power connector 50, regardless of the specifications of the vehicle in which it is installed. In the vehicle lighting fixture 1, the power source for the snow melting heater unit 7 can be selectively selected while keeping the specifications of the circuits, connection cords, and lamp units the same.

[0052] (Continuity check) As mentioned above, the snow melting heater unit 7 is connected to the lamp unit LU (tail lamp in this embodiment) which supplies power. The snow melting heater control unit 40 is configured to supply power to the heating element 6 for a predetermined time (a few seconds to about 20 seconds) when the lamp unit LU is electrically connected and power is supplied, regardless of the measurement value of the temperature sensor 8.

[0053] Therefore, by connecting the short-circuit cap 80 to the power connector 50 and setting the vehicle lighting fixture 1 to the second power supply mode, power is supplied to the taillights, and power is also supplied to the snow melting heater unit 7. Immediately after the power supply is started, power is supplied to the heating element 6 for a predetermined time, causing the current value to change. If the heating element 6 is not conducting, there is no change in the current value. With the above configuration, the snow melting heater unit 7 can perform a continuity check based on the change in current.

[0054] Conventionally, when the snow melting function could be switched ON / OFF depending on the temperature, there was a problem in that it was not possible to directly check the current continuity of the snow melting heater using a tester or similar device. In contrast, the snow melting heater unit 7 allows for continuity checks during the shipping inspection.

[0055] (modified version) Figure 6 is a cross-sectional view of vehicle lighting fixture 1A, which is a modified example of vehicle lighting fixture 1. Components with equivalent configurations are denoted by the same reference numerals and their descriptions are omitted.

[0056] Vehicle lighting fixture 1A has the same configuration as vehicle lighting fixture 1, except that the snow melting heater control unit 40A is fixed to the back cover 3, and the temperature sensor 8A is mounted as an electronic component in the snow melting heater control unit 40A of the snow melting heater unit 7A.

[0057] By positioning the snow melting heater control unit 40A outside the lamp chamber S, the external dimensions of the vehicle lamp 1A can be reduced. This allows for miniaturization and weight reduction of the lamp. The snow melting heater control unit 40A is not limited to the back cover; it can be positioned on the vehicle body side or the lamp side, as long as there is a fastening location. Thus, the snow melting heater control unit 40 can be positioned both inside and outside the lamp chamber S.

[0058] Since the temperature sensor 8A is mounted as an electronic component in the snow melting heater control unit 40A, which is located outside the lamp chamber S, it is not affected by the temperature rise inside the lamp chamber S and can measure the outside air temperature. By being mounted in the snow melting heater control unit 40A, which is located outside the lamp chamber S, its location is fixed and stable.

[0059] The configuration of this disclosure is not limited to rear lamps, but is also suitable for headlights and marker lights equipped with snow-melting functions for use in cold climates.

[0060] Although preferred embodiments of the present invention have been described above, these embodiments are merely examples of the present invention, and it is possible to combine them based on the knowledge of those skilled in the art, and such forms are also included within the scope of the present invention. [Explanation of symbols]

[0061] 1: Vehicle lighting fixtures 6: Heat-generating components 7: Snow melting heater unit 8: Temperature sensor 40: Snow melting heater control unit (control unit) 50: Power connector 60: Power cable 80: Short-circuit cap C: Connection cord S: Lamproom

Claims

1. A heating element that generates heat when power is supplied, a temperature sensor, a control unit that controls the power supply to the heating element based on the temperature sensor's measurement, a power supply, and a connecting cord connected to the control unit to supply power. Equipped with, The control unit is located inside or outside the lamp chamber. The aforementioned connecting cord is arranged so that at least a portion of it is exposed outside the lamp chamber, and the temperature sensor is provided on the portion of the connecting cord that is exposed outside the lamp chamber. The aforementioned connection cord is selectively connected to the vehicle power supply or the lighting power supply to receive power. A snow-melting heater unit for vehicle lighting fixtures, characterized by the following features.

2. The aforementioned connection cord has a power connector at its end. By connecting a power cable connected to the vehicle power supply, or a cap that short-circuits the circuit of the power connector, to the power connector, it is possible to selectively connect to either the vehicle power supply or the lighting power supply. The snow melting heater unit according to feature 1.

3. The control unit performs a control to supply power to the heat-generating element for a predetermined time when power supply to the control unit is started. A snow melting heater unit according to claim 1 or 2.

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