JPH0326425Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a remaining amount detection device for detecting the remaining amount in, for example, an automobile fuel tank.

[Prior art]

Generally, a fuel level warning light is installed in the driver's seat of a car to warn the driver that the remaining fuel level is low when the remaining level in the fuel tank falls below a predetermined level. A remaining amount detecting device is provided, and a thermistor is used as the sensor for detecting the presence or absence of fuel as a change in resistance.

As such a conventional remaining amount detection device, one shown in FIG. 4 is known.

In Fig. 4, reference numeral 1 denotes a casing made of stainless steel for rust prevention and installed in a fuel tank (not shown). It consists of a lid body 3 that covers the casing body 2,
The lid 3 is provided with oil passage holes 2A and 3A, and the lid 3 is provided with a bushing mounting hole 3B.
An explosion-proof mesh 4 is attached to the inner peripheral surface of the casing body 2, and a rubber bush 5 for fixing a lead wire, which will be described later, is fitted to the inner wall of the lid 3 through a bush mounting hole 3B. ing.

6 is a thermistor disposed inside the casing 1;
7A, 7B, 7C are lead wires that electrically connect the thermistor 6 (hereinafter referred to as lead wires 7A, 7B,
7C is collectively referred to as the "lead wire 7"), and as the lead wire 7, a signal wire called a Yumet wire (trade name) whose resistance changes little with respect to heat is used. Here, one end of the lead wire 7A is connected to a remaining amount alarm circuit (not shown), and the other end is connected to one end of the lead wire 7B via a soldered portion 8 within the rubber bush 5. Further, the other end of the lead wire 7B is directly connected to the side surface of the thermistor 6 via a soldered portion 9. Furthermore, lead wire 7C
One end is connected to the other side of the thermistor 6 via a soldering part (not shown), and the other end is connected to the bottom of the casing body 2 via a soldering part 10.

Incidentally, the casing 1 is attached to a fuel tank via a bracket, and is grounded together with the fuel tank, and is maintained at an earth potential.

In the remaining amount detection device configured as described above, changes in the oil level or remaining amount in the fuel tank are derived as changes in the resistance value by the thermistor 6, and when the remaining amount falls below a predetermined amount, a The remaining capacity warning light can be activated.

[Problem that the invention attempts to solve]

Now, since the fuel tank is a sealed container, depending on the surrounding humidity conditions, condensation may occur, moisture may accumulate in the fuel tank, and moisture may also get mixed into the gasoline, which is the fuel.

However, the lead wire 7 is connected to the soldered parts 8, 9, 10.
soldered, especially the soldered parts 9 and 10
are in direct contact with gasoline, so if electricity is applied to these soldered parts 9 and 10 with moisture in gasoline attached, the solder in the soldered parts 9 and 10 will be hydrolyzed and deteriorated. However, there is a problem that the lead wires 7B, 7C, etc. may be disconnected.

The present invention was devised in view of the above-mentioned problems caused by the use of a thermistor connected to a lead wire by soldering in the conventional remaining amount detection device. An object of the present invention is to provide a fuel tank remaining amount detecting device that uses an optical sensor consisting of a light receiving element, eliminates soldering means at the connection portion of a lead wire, and enables connection by crimping means.

[Means for solving problems]

In order to solve the above problems, the present invention includes a casing provided in a fuel tank, an explosion-proof mesh attached to the inner circumference of the casing, and a black resin cover provided on the inner surface of the explosion-proof mesh. a holder located within the casing and fixed to the casing, with a light emitting element and a light receiving element facing each other; and a terminal having one end attached to the holder and the other end protruding outside the casing; The fuel tank has a lead wire having one end crimped to the terminal and the other end extending outside the fuel tank.

[Effect]

Since gasoline, which is a fuel, is colored in a certain color, the light transmittance varies depending on the presence or absence of gasoline, and when the amount remaining in the fuel tank becomes low, the light receiving element becomes conductive. As a result, for example, the lamp,
Alarm means such as a buzzer can be activated.
On the other hand, since the lead wire is crimped to the terminal protruding from the holder to the outside of the casing, there is no risk of hydrolysis unlike conventional soldering methods, and sufficient water resistance measures against moisture intrusion can be taken. It can extend the lifespan. Moreover, by attaching an explosion-proof mesh to the inner circumference of the casing, the casing has an electrical explosion-proof structure, and by providing a black resin cover on the inner circumference of the explosion-proof mesh, light inside and outside the casing is This also blocks light from being reflected by the light emitting element.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 3.

In the figure, 11 is made of stainless steel,
The casing 11 is a casing disposed in a fuel tank T shown in FIG.
2. The lid body 13 has oil holes 12A, 13A, and one side of the casing body 12 has two screw holes 12B, 12B and bush mounting holes 12C, 12C in the height direction. The holes are drilled alternately.

Further, an explosion-proof mesh 14 is provided inside the casing body 12 to provide an electrical explosion-proof structure, and a black, oil-resistant resin cover 15 is provided on the inner surface of the explosion-proof mesh 14. Here, the resin cover 15 blocks light from inside and outside the casing 11, and prevents light from being reflected by a light emitting element 17, which will be described later.The resin cover 15 is made of, for example, polyacetal resin to ensure oil resistance. , an oil passage hole 15A is bored corresponding to the oil passage hole 12A. Note that the explosion-proof mesh 14 and the resin cover 15 are not limited to being provided only on the inner periphery of the casing body 12, but may be provided on the inner periphery of the lid body 13.

Reference numeral 16 denotes a holder provided inside the casing 11, and as shown in FIG. 2, the holder 16 includes a rectangular substrate portion 16A and a pair of element mounting elements spaced apart and protruding from the surface side of the substrate portion 16A. Part 16B, 16
It consists of C. A light emitting element 17 made of, for example, a light emitting diode is provided in one element mounting part 16B, and a light receiving element 18 made of, for example, a phototransistor is provided in the other element mounting part 16C. It is placed opposite to. On the other hand, on the back side of the substrate part 16A of the holder 16, two light emitting element terminal pins 19, 19 are provided at the upper and lower positions in the height direction, respectively.
Terminal pins 20, 20 for the light receiving element are provided protrudingly (second
(see figure), each terminal pin 19, 20 is attached to the holder 16
The length is such that it projects outside the casing 11 when it is attached to the casing 11.

Here, the holder 16 has screw holes 12B, 12
Each terminal pin 1 is fastened to one side of the casing 11 by screws 21, 21 inserted in B.
9 and 20 protrude to the outside through the bush mounting holes 12C and 12C, and the bush mounting holes 12C and
Rubber bushes 22, 22 that insulate between the casing body 12 and 12C are fitted.

Further, 23 indicates a lead wire for a light emitting element, 24 indicates a lead wire for a light receiving element, and each of the lead wires 23,
Crimp terminals 25 and 26 are respectively provided on one end side of 24, and each crimp terminal 25 and 26 is connected to the terminal pin 1.
9 and 20 to be fixedly connected. Each of the lead wires 23 and 24 has a positive side and a negative side, and the crimp terminal 2
5 and 26 correspond to each terminal pin 19 and 2.
0, and the positive side of each lead wire 23, 24 is connected to the remaining amount alarm circuit 27 shown in Fig. 3, and the negative side is connected to the fuel tank T, and is connected to the ground potential. is maintained.

Further, the remaining capacity alarm circuit 27 includes a comparator 28 using an operational amplifier, a warning light 29 consisting of a light emitting diode provided on the output side of the comparator 28, and a power terminal 30 provided between the power terminal 30 and the ground. voltage dividing resistor
The non-inverting input terminal of the comparator ₂₈ is connected to _the connection point a between _{the voltage dividing resistors R 1 and R 2 .}
The inverting input terminal is connected to the connection point b between the voltage dividing resistors R ₃ and R ₄ . The light emitting element 17 is connected to a power terminal 30 via a lead wire 23, and the light receiving element 18 is connected via a lead wire 24 at the connection point b.

The present embodiment is configured as described above, and its operation will be described next.

First, the oil level in the fuel tank T is L ₁ in Figure 3.
When the tank is full and the light-emitting element 17 and the light-receiving element 18 are immersed in the fuel as shown in , the light from the light-emitting element 17 does not pass through due to the coloring applied to the fuel, and the light-receiving element 18 is immersed in the fuel. is in a blocked state. In this state, the voltage at the connection point b due to the voltage dividing resistors R ₃ and R ₄ is determined by the voltage division ratio of these voltage dividing resistors R ₃ and R ₄ , and is it equal to the voltage at the connection point a due to the voltage dividing resistors R ₁ and R ₂ ? , or more, the output from the comparator 28 becomes zero or negative voltage, and the warning light 29 is turned on.
does not light up.

On the other hand, the oil level in the fuel tank T is L ₂ in Figure 3.
When the light emitting element 17 and the light receiving element 18 are exposed in the air, the light emitting element 17 becomes conductive due to the light from the light emitting element 17.
As a result, the voltage at connection point b becomes zero, and comparator 2
8 outputs a predetermined positive voltage, turns on the warning light 29, and warns the driver that the remaining amount in the fuel tank T is low.

However, in the remaining amount detection device according to this embodiment, the light emitting element 17 and the light receiving element 18 are placed in the holder 16.
and the holder 16 is provided in the casing 11,
The terminal pins 19, 20 are made to protrude outside the casing 11, and the terminal pins 19, 20 and the lead wires 23,
24 are fixedly connected by crimp terminals 25 and 26, there is no need to use soldering methods as in the prior art, and even if moisture is mixed in the gasoline, the fuel will not break. Since there is no fear of this, it is possible to ensure a water-resistant structure. On the other hand, since it uses a remaining amount detection method, it is not affected by the ambient temperature compared to a thermistor-based sensor, and does not fluctuate greatly depending on the surrounding conditions like a capacitance sensor, resulting in high accuracy. detection becomes possible. Furthermore, since a black oil-resistant resin cover 15 is provided on the inner peripheral side of the casing 11,
It exhibits light blocking and anti-reflection functions, making it possible to detect the remaining amount more reliably.

In the embodiment, the warning light 29 is used as an example of the warning means, but a warning buzzer may also be used. Moreover, although the holder 16 has been described as being fixed in the casing 11 so that the light emitting element 17 and the light receiving element 18 are arranged in the vertical direction, they may be fixed in the casing 11 so that they are arranged in the horizontal direction. Furthermore, it goes without saying that the remaining amount alarm circuit 27 is not limited to the circuit configuration of the embodiment.

[Effect of idea]

The fuel tank remaining amount detection device according to the present invention is as described in detail above, and includes a terminal provided on a holder for attaching a light emitting element and a light receiving element to the outside of the casing, and a lead wire is crimped to the terminal. Since the structure is fixed in place, there is no risk that the lead wire connection part will deteriorate or break due to moisture in the fuel, and a reliable connection can be maintained for a long period of time. An explosion-proof mesh is attached to the explosion-proof structure, and a black resin cover is provided on the inner surface of the explosion-proof mesh, so the resin cover has a light blocking function and anti-reflection function. The light emitting element and light receiving element enable more reliable detection of the remaining amount.

[Brief explanation of the drawing]

Figures 1 to 3 relate to embodiments of the present invention,
Fig. 1 is a longitudinal cross-sectional view of the remaining amount detection device, Fig. 2 is an external perspective view of the holder, Fig. 3 is a circuit configuration diagram of the remaining amount alarm circuit, and Fig. 4 is a longitudinal cross-section of the remaining amount detection device according to the conventional technology. It is a diagram. 11...Casing, 14...Explosion-proof mesh,
15...Resin cover, 16...Holder, 17...
Light emitting element, 18... Light receiving element, 19, 20... Terminal pin, 21... Screw, 23, 24... Lead wire, 25, 26... Crimp terminal, 27... Remaining amount alarm circuit, 29... Alarm light.

Claims (1)

[Scope of utility model registration request] A casing provided within the fuel tank, an explosion-proof mesh attached to the inner circumference of the casing, a black resin cover provided on the inner surface of the explosion-proof mesh, and a black resin cover located within the casing and fixed to the casing. a holder in which a light-emitting element and a light-receiving element are provided facing each other; a terminal having one end attached to the holder and the other end protruding outside the casing;
A fuel tank remaining amount detection device comprising a lead wire having one end crimped to the terminal and the other end extending outside the fuel tank.