JPH0218756Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an improvement of an automobile light control device that adjusts the brightness of illumination light that illuminates a panel board of a dash panel of an automobile.

[Technical background of the invention and its problems]

The first of its kind as a conventional automotive light control device.
The devices shown in FIGS. 4 and 15 are known.

This will be explained below.

1 is a printed circuit board motherboard on which a circuit pattern is printed, and electronic components 2 for an oscillation circuit, a power transistor 3 for a power driver circuit, and a variable resistor 4 for variable switching duty are soldered to the required circuits. .

A lead wire 5 from the motherboard 1 and a shaft 4a of the variable resistor 4 are led out from a case (not shown), and the lead wire 5 is connected to a power source and an illumination lamp. It controls the illuminance of the lighting lamp by varying the duty of oscillation switching.

In this way, conventional automotive light control devices used a variable resistor that was completed as a variable resistor, which resulted in a large case and required a large amount of installation space, which was inconvenient both in terms of cost and cost. was occurring.

In addition, there are drawbacks such as the fact that the power transistor of the power driver circuit is not heated properly, and the lead wires led from the motherboard require an intermediate connector to connect with the lead wires from the power supply and lighting lamps. Had to have.

[Purpose of invention]

The present invention aims to eliminate the above-mentioned drawbacks of conventional automotive dimmers.The terminal and the resistor of the variable resistor are integrally installed on the circuit board, and the variable resistor is slidably mounted on the case. In addition to being equipped with terminals, the outer shell of the connector is made, and the connector is formed with the terminals, eliminating the need for an intermediate connector, making it possible to realize miniaturization and cost reduction, and perfecting the heat dissipation of the power transistor to prevent failures. The purpose is to prevent such occurrences.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

Reference numeral 11 denotes a heat dissipation plate made of a metal with good thermal conductivity, which is bent into a U-shape, one side of which is formed into a terminal 11a, and a punched piece 11 at its base.
b is bent, and on the other side there is a bulge 1 that bulges left and right.
1c and an upwardly bent protrusion 11d, and a power transistor 12, which generates a large amount of heat, is mounted in the center with their heat dissipation surfaces overlapped.

13 is the motherboard which is a printed circuit board,
Round 13a and through hole 1 for terminal installation
3b is provided, and a resistance coating 14a of a variable resistor is installed on one surface thereof, and the surface thereof,
Alternatively, a circuit pattern is printed on the back surface, and electronic components 15 are attached by hand at required locations.

It should be noted that there is no problem even if the motherboard 13 is made of a material with poor thermal conductivity or has poor temperature characteristics such as the electronic components 15 mounted thereon having low heat resistance.

16 is a terminal board, and the terminal 11a of the heat sink 11
Similarly, a punch book 16b is provided at its base.

The terminal 11a of the heat sink 11 and the terminal plate 16 are inserted into the motherboard 13 so that the motherboard 13 is sandwiched between the punched pieces 11b and 16b, and the round 13a and the punched pieces 11b and 16b are soldered.

Further, the protruding piece 11d of the heat sink 11 is attached to the motherboard 1.
Insert into the through hole 13b of No. 3 and solder it.
The heat sink 11 and the terminal board 16 are thus attached to the motherboard 13, and the legs 12a of the power transistor 12 are also soldered to the circuit pattern of the motherboard 13.

Reference numeral 17 denotes a case made of an insulator such as plastic, and has an outer shell 17a of the connector on the back side, an insertion hole 17c in the partition wall 17b of the outer shell 17a, and a support rail 17d and an insertion hole 17e on the inner surface. Shafts 17f are respectively formed on the upper inner surface into which knobs 14c of variable resistors having sliding terminals 14b can be rotatably inserted.

After inserting this knob 14c into the shaft 17f,
When the motherboard 13 is inserted into the support rail 17d by inserting the terminals 11a and the terminal plate 16 from the insertion holes 17c toward the outer shell 17a, the bulges 11c fit into the insertion holes 17e and the motherboard 1
3 can be attached, and the outer part 17a, the terminal 11a, and the terminal plate 16 form a connector.

When the knob 14c is rotated from the outside, the sliding terminal 14b slides on the resistive coating 14a, and the resistance value can be made variable. Therefore, the duty of self-oscillation switching can be varied, and the illumination intensity can be varied. It is something that can be adjusted.

[Description of other embodiments]

Next, a second embodiment will be described with reference to FIGS. 6 to 9.

In the previous embodiment, the knob 14 was inserted from the side of the case 17.
The illuminance was adjusted by rotating the shaft 27a laterally, but in this embodiment, the shaft 27a is mounted on the upper surface of the upper case 27a.
4d protrudes and is rotated to adjust the illuminance, and a connector is formed on the upper surface of the lower case 27b.

Reference numeral 21 denotes a heat sink, which is bent into a U-shape as in the previous embodiment, and has a power transistor 22 attached to its center, a terminal 21a, and a punched piece 21b.
Although the projecting piece 21d is formed, its terminal 21a
is further bent downward.

Reference numeral 23 denotes a motherboard of a printed circuit board, which is provided with a variable resistance resistive film 24a, a circuit pattern, rounds 23a for terminal attachment, and through holes 23b, and the necessary electronic components 15 are soldered thereto.

26 is a terminal plate, and a punched piece 26b is provided at the base of the terminal plate.

The terminal 21a of the heat sink 21 and the terminal board 26 sandwich the motherboard 23 between the punched pieces 21b and 26b, and the protruding piece 21d of the heat sink 21 is inserted into the through hole 23b of the motherboard 23 to remove the punched piece 21.
b, 26b, the round 23a, the protrusion 21b and the through hole 23b are attached by hand, the heat sink 21 and the terminal board 26 are attached to the motherboard 23, and the legs 22a of the power transistor 22 are soldered to the motherboard 23, as in the previous embodiment. It is similar to

The case 27 that accommodates such a motherboard 23 is formed of an upper case 27a and a lower case 27b, and the upper case 27a has a shaft bearing hole 27c into which a shaft 24d of a rotating piece 24c provided with a sliding terminal 24b is inserted. , an engagement hole 27e is formed that engages with a protrusion 27d of the lower case 27b to be in a closed state.

In addition to the protrusion 27d, the lower case 27b includes:
The outer shell part 27f of the connector, the terminal 21a,
An insertion hole 27g into which the terminal plate 26 is inserted is provided on the lower surface.

The shaft 24 is inserted into the bearing hole 27c of the upper case 27a.
d, and then insert the terminal 21a and the terminal plate 26 into the insertion hole 2.
7g and insert the motherboard 23 into the lower case 27
b, and when the upper case 27a and the lower case 27b are overlapped and the protrusion 27d and the engagement hole 27e are engaged to be in the closed state, the rotary piece 24c of the variable resistor is rotatably supported. , the sliding terminal 24b has a resistive coating 2
4a, the resistance value can be made variable.

Therefore, a knob is attached to the shaft 24d, and the illuminance can be adjusted by rotating the knob.

Furthermore, a third embodiment in which the variable resistor is of a sliding type will be explained with reference to FIGS. 10 to 13.
This example is the same as the second one except for the parts explained below.
There is no difference from the embodiment.

The resistance coating 24a of the variable resistance provided on the motherboard 23 is formed in a linear shape, and a linear guide hole 27h is formed in the upper case 27a.

The operating knob 24e provided with a variable resistance sliding terminal 24b can be inserted into the guide hole 27h and slid linearly along the guide hole 27h, and can adjust the illuminance by changing the resistance value. It is possible.

The present invention is not limited to those shown in the embodiments, and can be modified in various ways, such as providing a connector at a position other than the position described above, or making the case have a shape other than a housing shape.

[Effect of idea]

As described in the present invention, a variable resistor is installed on a board on which electronic components are mounted, and it functions as a variable resistor by assembling it, without using a completed variable resistor. Therefore, the volume is reduced compared to a conventional variable resistor using a completed variable resistor, and the circuit can be made denser, and the size can be reduced, and the installation space can be reduced.

Since the resistor can have a unique resistance curve, it is also possible to match the operating state and illuminance adjustment.

Furthermore, by providing the connector terminals directly on the board,
Since the connector is formed together with the case, there is no need to attach the lead wires by hand and solder the connectors to the lead wires as in the conventional case, and therefore parts costs and assembly costs can be reduced.

Moreover, since the connector and variable resistor terminals do not need to be soldered, which was a major factor in reducing reliability in the past, reliability is greatly improved.

In addition, the power transistor that generates a large amount of heat in the power driver circuit is attached to a heat sink, and a space is formed between the heat sink and the board, so air flows through this space and cools the heat sink and power transistor. is carried out well, and the temperature rise can be reduced.

At the same time, this space prevents heat from the heat sink and power transistor from being transmitted to the board, allowing the use of boards and electronic components with low heat resistance, which leads to cost reduction. It has many features such as the ability to

[Brief explanation of the drawing]

1 to 5 show a first embodiment of the present invention, FIGS. 6 to 9 show a second embodiment, and FIGS. 10 to 13 show a third embodiment. Figures 6 and 10
The figure is an exploded perspective view, Figure 2 is a perspective view of the back side of the motherboard, Figures 3, 7, and 11 are assembled views of the motherboard, Figures 4 and 5, Figures 8 and 9,
FIGS. 12 and 13 are perspective views from opposite sides in an assembled state, and FIGS. 14 and 15 are perspective views from opposite sides of a conventional automotive light control device. 11, 21... Heat sink, 11a, 21a... Terminal,
12, 22...power transistor, 13, 23...
Motherboard, 14a, 24a... Resistance film of variable resistance, 14b, 24b... Sliding terminal, 15... Electronic component, 16, 26... Terminal board, 17... Case, 27a
...Upper case, 27b...Lower case, 17a, 27f
...outer part of the connector, 17c, 27g...insertion hole for the terminal board.

Claims (1)

[Scope of Claim for Utility Model Registration] A heat sink to which a power transistor is attached and a portion of which is formed as a terminal; most of the heat sink is separated and attached at both ends; and a slider of a variable resistance is attached to the slider. a substrate on which a resistor for controlling a moving power transistor, electronic components, and terminals are attached to a circuit pattern; a sliding terminal of the variable resistor is slidably accommodated in the resistor together with the substrate; A case forming a connector; and a variable resistance operator rotatably or slidably supported on the connector, and the terminal attached to the board is a male terminal of the connector. Automotive light control device.