JPH031772Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a fuel level sensor for measuring the amount of fuel remaining in an automobile fuel tank.

(Prior Art) A float arm type variable resistance unit as shown in FIG. 8 has been commonly used as a fuel level sensor for automobiles. This allows the movement of the float 21 that follows vertical fluctuations in the fuel level to be transferred to the contact lever 2 via the float arm 22.
This is a mechanism that transmits information to the third party. Contact lever 23
Due to the movement of , contact 2 attached to the contact lever
4 is a wire-wound resistance type or thick film resistance type resistor 2
5, the resistance value changes. Further, in order to issue a warning to the driver when the remaining amount of fuel is low, a remaining amount warning sensor 26 as shown in FIG. 8 is attached to the support rod 27. This remaining amount warning sensor 26 is connected to a support rod 27 mounted with wheels 28 via a spring so that the distance between the fuel tank and the bottom of the tank is always maintained constant against deformations such as expansion and contraction of the fuel tank. It is attached to a mounting base 29. As described above, a fuel tank liquid level sensor using a float arm type variable resistance unit has a complicated structure incorporating various mechanisms.

(Problem to be solved by the invention) As shown in Figure 9, the float arm type variable resistance unit described above is a contact detection type that electrically detects the change in resistance value due to sliding contact between the lever contact and the resistor. Because of this structure, detection accuracy tends to deteriorate due to variations in manufacturing, a decrease in contact pressure due to wear of the sliding contact, an increase in contact resistance, etc. Furthermore, since the resistance wire is wound around the board, it is easily broken at the corners of the board, and also at the sliding portion of the lever contact. Furthermore, the float not only moves up and down, but also moves left and right depending on the inclination of the liquid level, and at this time friction occurs at the arm fulcrum, which may impede the smooth movement of the arm.

Furthermore, since the float arm type variable resistance unit detects vertical changes in the fuel level instead of the rotational movement of the float arm, the response is non-linear, and the degree of detection of the liquid level decreases particularly near the empty position. For this reason, it is necessary to separately provide a remaining amount warning sensor 26 attached to an independent support rod 27. Furthermore, as shown in FIG. 9, the structure of the contact has a large number of parts, such as a contact lever 24, a conductive spring 30, a contact base 31, and nuts that hold them down from above and below. Also, when there is a large amount of fuel on the bottom of a car's fuel tank,
It bends under the weight, and when the amount of fuel decreases, the bend returns to its original state. In addition, even a slight difference between the internal and external pressures causes the tank to deflect. Since the liquid level rises and falls with this deflection, the unit installed from the top of the tank has wheels 28 and support rods 2 as described above.
7. Requires parts such as springs and remaining amount warning sensor 26. The large number of these parts increases the cost of the unit.

In addition, the float arm type variable resistance unit has a complicated overall shape with branches as shown in Figure 8, and when it is installed in the fuel tank, it must be inserted through the mounting hole, making it difficult to assemble. Poor workability.

In addition, in recent automobiles, the shape and space of the trunk room, the location and space for storing the spare tire and the fuel tank have diversified due to changes in the shape of the car body due to compactness and aerodynamic design. Their shapes also tend to become more complex and diverse. Inside the fuel tank, the inside of the tank is divided into small chambers to prevent the sudden flow of fuel while driving, protect the fuel gauge float, reduce the noise of fuel flowing, and sometimes serve the role of reinforcing the outer wall of the tank. Flexibility in plate design is required. Furthermore, when installing the fuel pump inside the fuel tank, it is also necessary to secure the installation space. As the shapes and internal structures of fuel tanks tend to become more complex and diverse, the design of conventional float arm type variable resistance units becomes obstructive due to the large operating area of the float and arm, as shown in Figure 10. It's becoming a problem.

In addition, conventional fuel level warning sensors only turn on a warning light when the remaining fuel level falls below a predetermined level, but do not notify the driver of the remaining fuel level after the warning light lights up. This is causing unnecessary anxiety to drivers and has become a serious problem.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned problems, and the fuel level sensor for a fuel tank according to the present invention includes a column vertically disposed inside the fuel tank, a generatrix disposed on the strut along the vertical axis of the strut; a plurality of contact points disposed on the strut at predetermined intervals along the vertical axis of the strut; a plurality of resistors each connected between the contacts of a plurality of resistors, a float slidably fitted to the pillar, and a conductive sliding piece mounted on the float, and a conductive sliding piece mounted on the float in a vertical direction of the sliding piece. a sliding piece whose length is such that the two adjacent contacts are always connected to the bus bar, and which forms an electrically closed circuit by connecting the contacts and the bus bar; a pressing means for pressing the fuel tank against the support; a remaining amount warning means comprising a light emitting element connected between a predetermined contact among the plurality of contacts and ground; and a distance between the predetermined contact and the bottom surface of the fuel tank. a base member that mounts the support column on the fuel tank, and a spring that is mounted between the base member and the support column and presses the support column toward the bottom of the fuel tank. It has a spacing holding mechanism.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 to 7.

Reference numeral 1 denotes a mounting base for mounting on a fuel tank, and a strut guide 2 and a cover guide 3 are fixed to the lower surface of the mounting base 1. The strut guide 2 is a tubular body with a rectangular cross section, and long holes 4 are formed in two opposing sides. A column 5 vertically disposed on the fuel tank is inserted into the column guide 2 so as to be movable up and down.
A female thread is formed at a location corresponding to , and a suitable bolt 6 passes through the elongated hole 4 and is screwed into the female thread. Furthermore, a compression coil spring 7 is provided between the mounting base 1 in the strut guide 2 and the end of the strut 5.
is interposed to urge the support column 5 downward. The column 5 is made of magnetic material and is further provided with a generatrix 8 along the longitudinal axis of the column. The surface of the bus bar 8 slightly protrudes from the surface of the support column 5. Furthermore, a plurality of contact points S _o are arranged on the column 5 at predetermined intervals along the longitudinal axis, and also protrude slightly from the surface of the column. An equivalent resistor R is connected between each contact and forms an electric circuit with the bus bar 8 as shown in FIG. A float 9 is loosely fitted to the support column 5, and moves up and down according to changes in the liquid level in the fuel tank. A conductive sliding piece 10 is attached to the float 9.
A permanent magnet 11, which is a pressing means for pressing the sliding piece 10 against the pillar 5, that is, the bus bar 8 and the plurality of contacts S, is mounted on the back surface of the sliding piece 10. As mentioned above, in this embodiment, the support column 5 is made of a magnetic material, so the conductive sliding piece 10 is connected to the bus bar 8 and the contact point S by the magnetic force of the permanent magnet.
will be under pressure. The length of the sliding piece 10 along the longitudinal direction (vertical direction) of the support 5 is a length that always connects two adjacent contact points S to the bus bar 8 at the same time.

FIG. 5 shows an electric circuit according to the present invention, in which, as mentioned above, an equivalent resistor R is connected between a plurality of contacts S, and the entire circuit is adjusted depending on the position of the contact S connected to the bus bar 8. The resistance of the circuit changes. A light emitting diode 13 serving as a remaining amount warning means is connected between the contact point S _o-2 near the empty terminal and the ground (between AB in FIG. 5). Reference numeral 14 is a fuel gauge.

A cover 12 is slidably fitted into the cover guide 3 and surrounds the support column 5 and the float 9. A through hole 15 is formed at the bottom of the cover 9, and a filter 16 is provided in the hole.

The fuel level sensor of the present invention with the above configuration is the seventh
As shown in the figure, the support column 5 and the cover 12 are vertically mounted so as to contact the bottom surface of the fuel tank 18 by means of a compression coil spring 7 mounted between the support column 5 and the mounting base 1.

Next, the effect will be explained.

The fuel in the fuel tank is passed through the through hole 15 of the cover 12.
and enters the liquid level sensor through the filter 16. As a result, the float 9 is moved up and down along the column 5 in response to changes in the liquid level. The conductive sliding piece 10 mounted on the float 9 is pressed against the bus bar 8 and the contact S by the magnetic force of the permanent magnet 11 which tends to attract the support column 5. Therefore, the sliding piece 10
connects the contact S corresponding to the liquid level position to the bus bar 8. The length of the sliding piece 10 in the direction along the support is always the length that connects two adjacent contacts S to the bus bar 8 at the same time, so when the sliding piece 10 moves to the adjacent contact S, the electric circuit is connected. It will never be opened. In other words, the amount of liquid in the fuel tank can be displayed at all times. When the float is in the uppermost position, contacts S ₁ and S ₂ are connected to the bus bar 8 at the same time. The total resistance of the circuit at this time is R ₀ . When the liquid level then falls, contacts S ₂ and S ₃ are connected to bus bar 8 and the total resistance of the circuit becomes R ₀ +R ₁ . When the float 9 is at the lowest position, the total resistance of the circuit is R ₀ +R ₁ +...+R _o-2 +R _o-1 . in this way,
Since the resistance of the circuit changes as the liquid level changes, the current flowing through the circuit also changes as the liquid level changes. By passing this current through the level gauge, the amount of fuel in the fuel tank is measured.

Furthermore, since the light emitting diode 13 is connected between the contact S _o-2 near the empty terminal and the ground (between AB in Fig. 5), the contacts S _o-1 and S _o are connected to the bus bar 8. and the potential difference corresponding to the resistance R _o-2 is AB
During this period, a light emitting diode, or warning light, lights up. Next, when the fuel in the tank decreases further and the lowest contact S _o is connected to bus bar 8, the resistance
A potential difference equivalent to R _o-2 + R _o-1 is generated between AB, causing the light emitting diode to light up even brighter. This allows you to know the change in fuel in the tank after the warning light is turned on.

As mentioned above, since the support column 5 is always pressed against the bottom surface of the fuel tank 18, the distance between the contact point S _o-2 to which the light emitting diode is connected and the tank bottom surface is always maintained constant, so that the bottom surface does not change. Even if there is a problem, the warning light can always be turned on when the remaining amount is at a certain level.

In this embodiment, the means for pressing the conductive sliding piece 10 against the bus bar 8 and the contact S is achieved by making the support 5 a magnetic material and mounting a permanent magnet on the back surface of the sliding piece. However, this can also be changed to the pressing means shown in FIG. The pressing means is a spring 17 interposed between the back surface of the sliding piece 10 and the float. With this configuration, the struts 5 do not need to be made of magnetic material.

(Effects of the invention) According to the invention, since the sliding piece slides on the generatrix and the contact point, a liquid level sensor is provided that does not cause resistance changes due to wear and does not have the risk of cutting the resistance wire. .

Furthermore, since the remaining amount warning means can be incorporated in the form of a single support, a liquid level sensor with a simple structure, a small number of parts, and an inexpensive price can be provided.

Furthermore, since the liquid level is detected by vertical movement of the float, the liquid level detection accuracy is high.
A liquid level sensor that requires less operating space is provided.

Furthermore, since the entire structure is in the form of a single column, a liquid level sensor that can be easily assembled to a fuel tank is provided.

Furthermore, since the cover is provided, a liquid level sensor that is not sensitive to sudden changes in the liquid level due to acceleration, deceleration, turning, etc. of the automobile is provided.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a fuel level sensor for an automobile fuel tank according to the present invention. FIG. 2 is a front view of the liquid level sensor of the present invention. FIG. 3 is a sectional view of the float seen from the - line in FIG. 2. FIG. 4 is a sectional view of the float similar to FIG. 3, and is a sectional view showing another embodiment. Fifth
The figure is an electrical circuit diagram used in the liquid level sensor of the present invention. FIG. 6 is a partial cross-sectional view showing the strut guide and strut portion of the liquid level sensor of the present invention. FIG. 7 is a sectional view showing the liquid level sensor of the present invention installed in a fuel tank. FIG. 8 is a perspective view of a conventional float arm type variable resistance liquid level sensor. FIG. 9 is a partial view showing a sliding contact portion of a conventional float arm type variable resistance liquid level sensor. FIG. 10 is a sectional view showing a conventional float arm type variable resistance liquid level sensor installed in a fuel tank. 1... Mounting base, 2... Pillar guide, 3...
...cover guide, 4...long hole, 5...post, 6...
...Bolt, 7...Compression coil spring, 8...Bus bar,
9...Float, 10...Sliding piece, 11...Permanent magnet, 12...Cover, 13...Light emitting diode, 14...Liquid level gauge, 15...Through hole, 16...
Filter, 17...Spring, 18...Fuel tank, S...Contact, R...Resistance.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A strut vertically disposed within a fuel tank, a generatrix disposed on the strut along the vertical axis of the strut, and a vertical axis of the strut. a plurality of contacts disposed at predetermined intervals on the pillar along the column; a plurality of resistors respectively connected between the plurality of contacts; and a float slidably fitted to the pillar. , a conductive sliding piece mounted on the float, the vertical length of the sliding piece being a length that always connects the two adjacent contacts to the bus bar; A sliding piece that forms an electrically closed circuit by connecting a bus bar; a pressing means that presses the sliding piece against the support; and a contact between a predetermined contact among the plurality of contacts and the ground. a remaining amount warning means comprising a light emitting element connected to the fuel tank; a base member for mounting the support on the fuel tank with a mechanism for maintaining a constant distance between the predetermined contact point and the bottom surface of the fuel tank; A fuel level sensor for an automobile fuel tank, comprising: a spacing mechanism comprising a spring mounted between the support and the support to press the support towards the bottom of the fuel tank. (2) Utility Model Registration In the liquid level sensor according to claim 1, the pressing means is mounted on the support made of a magnetic material and on the back surface of a conductive sliding piece mounted on the float. A liquid level sensor consisting of a permanent magnet. (3) Utility Model Registration The liquid level sensor according to claim 1, wherein the pressing means is a spring mounted between the conductive sliding piece and the float. (4) Utility Model Registration The liquid level sensor according to claim 1, wherein the liquid level sensor has a cover with a hole at the bottom. (5) Utility Model Registration The liquid level sensor according to claim 4, wherein the hole is provided with a filter.