JP2003050151A - Level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a level detector which eliminates a dead zone, when a level is lowered, and which simplifies circuit. SOLUTION: The level detector 100 is provided with a permanent magnet 10, which is fixed and arranged at the prescribed position of a float 8 and many Hall ICs 51 to 5n , which are fixed and arranged on a board 4 along the vertical direction. The Hall ICs 51 to 5n are set to an electrical ON-state, when they nearly face the permanent magnet 10. A series resistance circuit 20, which is constituted by serially connecting resistances 201 to 20n installed, so as to correspond to the Hall ICs 51 to 5n in a one-to-one manner is provided on the output side of the Hall ICs 51 to 5n . When one Hall IC or a plurality of Hall ICs, adjacent in the up-and-down direction, are set at ON-state due to change in the level, a current is made to flow to a combined resistance up to the resistance 201 , facing the uppermost end Hall IC 51 from among all of the Hall ICs 51 to 5n from the resistance, corresponding to the uppermost end Hall IC from among the Hall ICs in the ON-state, and the level is detected, on the basis of the current amount of the combined resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detecting device, and more particularly, to a liquid level level of liquid fuel in a vehicle fuel tank, liquid in a liquid storage tank, kerosene in a petroleum stove, water in a bath or the like. The present invention relates to a liquid level detection device for detecting the water level of a river.

[0002]

2. Description of the Related Art Conventionally, as described in JP-A-7-260552 and Japanese Patent No. 3028176, a liquid level detecting device is provided with a plurality of magnets inside a float, and the magnets are electrically connected with the displacement of the float. There has been proposed a liquid level detection device that detects a liquid level based on a combination of magnetically sensitive switch groups such as Hall elements that are brought into a state.

[0003]

However, according to the above-mentioned prior art, since the plurality of magnets are provided in the float in the vertical direction, the vertical dimension of the float becomes long, and therefore, the liquid level. Lowers and the bottom of the float comes to the bottom of the tank,
There is a problem that a dead zone is generated which makes it impossible to detect a decrease in the liquid level thereafter. Further, since the liquid level is detected based on the change in the combination of the magnetically sensitive switch groups that are brought into conduction with the displacement of the float, the calculation processing circuit for calculating the above combination is operated. There is also a problem that the configuration becomes complicated.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a liquid level detecting device capable of eliminating the dead zone when the liquid level is lowered and simplifying the circuit. To do.

[0005]

A liquid level detecting device according to the present invention comprises a float which is allowed to move in the vertical direction following changes in the liquid level and a permanent magnet fixedly arranged at a predetermined position of the float. A plurality of Hall ICs fixedly arranged in the vertical direction on a substrate arranged on the liquid container side, each of which is arranged so as to be able to face a permanent magnet that moves vertically as the float moves vertically. , Hall ICs that are electrically turned on when they are substantially opposed to the permanent magnets, and one-to-one with each Hall IC on the output side of the multiple Hall ICs.
And a series resistance circuit configured by connecting resistances provided in correspondence with the above, and one hole I in accordance with a change in liquid level.
When a plurality of Hall ICs adjacent to each other in the vertical direction is in the ON state, the resistance corresponding to the uppermost Hall IC of the Hall ICs in the ON state is changed to the uppermost Hall IC of the plurality of Hall ICs. It is characterized in that a current is caused to flow through the combined resistance up to the opposing resistance, and the liquid level is detected by the amount of current of this combined resistance.

The Hall IC is a one-side magnetic field operating Hall I which is activated when the S pole or N pole of the permanent magnet approaches.
It is C.

A remaining amount warning circuit is connected to the series resistance circuit.

The float, the permanent magnet, and the large number of Hall ICs are arranged in the respective concave portions of a liquid container having a plurality of concave portions on the same horizontal plane, and one to one hole ICs are provided for each concave portion. Correspondingly, the series resistance circuits are provided and the plurality of series resistance circuits are connected in series, and the total combined resistance of the entire plurality of series resistance circuits is the total combined resistance of the series resistance circuits for each recess. A current is caused to flow through the total combined resistance obtained by combining in a plurality of series resistance circuits, and the liquid level is detected by the current amount of the total combined resistance.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view and a horizontal sectional view (a sectional view taken along the line BB in FIG. 1A) of the liquid level detecting device according to the first embodiment. FIG. 2 is a circuit of the liquid level detecting device. FIG. 3 is a circuit diagram of the Hall IC, FIG. 4 is a simplified circuit diagram for explaining the circuit operation of FIG. 2 in an easy-to-understand manner, and FIG. 5 is a timing chart for explaining the circuit operation of FIG. Show.

Liquid level detection device 100 according to the first embodiment
As shown in FIG. 1, while securing the sealing property so as not to leak the liquid inside the liquid container 1 to the peripheral portion of the mounting hole 1b provided in the top plate portion 1a of the liquid container 1 such as a vehicle fuel tank, It is attached and arranged inside the liquid container 1 to detect the liquid level of the liquid. Liquid level detection device 10
Reference numeral 0 includes a lid portion 2 that closes the mounting hole 1b of the top plate portion 1a of the liquid container 1, and a tubular portion 3 on the lower surface of the lid portion 2. The tubular portion 3 has a bottom plate portion 3 a arranged near the bottom plate portion 1 c of the liquid container 1, and a plurality of bottom plate portions 3 a that communicate between the inside of the tubular portion 3 and the liquid container 1 are provided. The communication holes 3b are formed, and when the liquid inside the liquid container 1 is in a stationary state (steady state), the liquid level of the liquid inside the tubular portion 3 is equal to that of the liquid container 1 due to the communication holes 3b. It matches the liquid level of the liquid inside. At the center of the inside of the tubular portion 3 in a plan view, a vertically long and slender substrate 4 is provided between the top plate portion 3c and the bottom plate portion 3a. A large number of Hall ICs 5 _{1 to} 5 _n are mounted on _one surface of the substrate 4 in the vertical direction at equal intervals, and an electronic circuit 6 is arranged on the other surface of the substrate 4. In addition, inside the tubular portion 3,
The top plate portion 3c and the bottom plate portion 3 of the tubular portion 3 are sandwiched so as to sandwich the substrate 4.
Two guide posts 7 are provided vertically and parallel to each other with a. Two guide posts 7
Are partially engaged with the notches 9 formed on the outer peripheral surface of the hollow cylindrical float 8, respectively.
The vertical movement of the float 8 due to the change of the liquid level is allowed while controlling the position on the horizontal plane. The substrate 4 is located inside the inner peripheral surface of the float 8 and is located at a predetermined position on the inner peripheral surface of the float 8, that is, each of the Hall ICs 5 _{1 to} 5 on the substrate 4.
_The permanent magnet 10 is fixedly arranged at a position _where it can face _n . The permanent magnet 10 has an N pole and an S pole in the vertical direction, and the Hall ICs 5 _{1 to} 5 _n are one-side magnetic field operating Hall ICs that operate when the S pole of the permanent magnet 10 approaches. preferable.

Liquid level detection device 1 having the above structure
At 00, the change in the liquid level of the liquid inside the liquid container 1 appears as a change in the liquid level of the liquid inside the tubular portion 3, and the change in the liquid level of the liquid inside the tubular portion 3 becomes Along with the change, the float 8 moves up and down while being guided by the two guide posts 7. When the float 8 moves up and down, the permanent magnet 10 fixedly arranged on the inner peripheral surface of the float 8 also moves up and down, and the Hall ICs 5 _{1 to} 5 _n facing the permanent magnet 10 sequentially change. .

Next, the configuration and operation of the circuit of the liquid level detecting device 100 will be described.

In the circuit of the liquid level detecting device 100 shown in FIG. 2, a common DC voltage is applied to the large number of Hall ICs 5 _{1 to} 5 _n located at equal intervals in the vertical direction as described above.

The circuit of each of the Hall IC 5 ₁ to 5 _n, is constructed as shown in FIG. 3, each hole IC 5 ₁ to 5
_n is a hall element 11, a regulator 12 that supplies a stabilized power supply to the hall element 11, an amplifier 13 that amplifies a weak output of the hall element 11, and an on / off operation by the output of the amplifier 13 to perform chattering. Schmitt trigger 14 having hysteresis characteristics for prevention
And a transistor (output stage) 15 which is turned on by the Hi level output of the Schmitt trigger 14 and turned off by the Lo level output.

Each Hall IC 5₁ ~ 5_n The Transis
The collector of the output terminal 15 (the output end of the output stage) is connected to the DC power supply.
Switching transistor 16 to which the mitter is connected₁ ~
16 _n Connected to the base of each of the switching
Transistor 16₁ ~ 16_nIs the corresponding Hall IC5₁
 ~ 5_n Since the base current does not flow when the
Turns off and the corresponding Hall IC5₁ ~ 5_n Is on
In the state, the base current flows to turn on.

Each switching transistor 16₁ ~
16_n Bias collector 17₁ ~ 17_n as well as
Enhancement type MOSFET 18₁ ~ 18_n The game
Connected. MOSFET 18₁ ~ 18_n Is
Switching transistor 16₁ ~ 16_n Is off
When it is turned off, the switching transistor 16 ₁ 
~ 16_n Is on, bias resistor 17₁ ~ 17_n 
Is turned on because a current flows through the gate and a positive voltage is applied to the gate.
It becomes a state.

The sources of the MOSFETs 18 ₁ to 18 _n are connected to each other and grounded via a resistor 19.
Further, the drain of the MOSFET 18 ₁ located at the uppermost end has a resistance 2 corresponding to the MOSFET 18 ₁ in a one-to-one relationship.
It is connected to the positive side output terminal 21 via 0 ₁ . Furthermore, M located just below the uppermost MOSFET 18 ₁
OSFET18 ₂ or later of each MOSFET18 ₂ ~18 _n
The drains, the resistance through the resistor 20 ₂ to 20 _n corresponding to the one-to-one to each MOSFET 18 ₂ ~ 18 _n, corresponding to the MOSFET 18 ₁ ~ 18 _n-1 of the upper adjacent 20
It is connected to the _{1 ~20 n-1.} The resistor 20 _n corresponding to the MOSFET 18 _n is located at the lowermost end is connected to the negative output terminal 23 via a resistor 22. Therefore, between the positive side output terminal 21 and the negative side output terminal 23, the MOSFET 18 _{1 at the} uppermost end to the MOSF at the lowermost end is connected.
A series circuit of resistors 20 _{1 to} 20 _n corresponding to the respective MOSFETs 18 ₁ to 18 _n up to ET 18 _n , that is, a series resistance circuit 20, is connected, and resistors 20 adjacent to each other are connected.
The drains of the MOSFETs 18 ₁ to 18 _n are connected between _{1 to} 20 _n .

The above-mentioned circuit portion in the entire circuit shown in FIG. 2 constitutes a liquid level detection circuit 101 for detecting the liquid level of the liquid inside the cylindrical portion 3. Next, the operation of the liquid level detection circuit 101 will be described with reference to the simplified circuit shown in FIG. 4 which is a simplified version of the liquid level detection circuit 101 and the timing chart of FIG.

The simplified circuit shown in FIG. 4 is provided with six switch elements S1 to S6 and resistors R1 to R6 corresponding to the switch elements S1 to S6 in a one-to-one manner, and the positive side output terminal 21 is provided with a liquid level. It is configured by connecting a meter M for displaying. Here, the switch elements S1 to S6 are the Hall ICs 5 _{1 to} 5 _n and the switching transistors 16 ₁ to in FIG.
16 _n , bias resistors 17 _{1 to} 17 _n, and MOSFET
18 ₁ to 18 _n are replaced and represented. Further, in the timing chart shown in FIG. 5, the substrate 4 is provided on the upper side, the switch elements S1 to S6 respectively corresponding to the six Hall ICs arranged on the substrate 4 at equal intervals in the vertical direction, and the Hall ICs. Permanent magnet 1 that can face
0, and the lower part shows the relationship between the vertical position of the permanent magnet 10 and the operating states of the switch elements S1 to S6. Each Hall IC is a permanent magnet 1
This is a one-sided magnetic field operation Hall IC that operates when the S pole or N pole of 0 approaches.

The six switch elements S1 to S6 have an operation pattern as shown in FIG. 5 with respect to the vertical position of the permanent magnet 10, that is, the liquid level, and the six switch elements S1 to S6.
1 to S6 are operation patterns in which only one of the switch elements is in the ON state (provisionally referred to as a single ON operation pattern) and operation patterns in which adjacent switch elements are in the ON state (probably referred to as a double ON operation pattern). ) 2
It has one operation pattern. In the simple ON operation pattern, current flows only to the switch element in the ON state in the simple circuit shown in FIG. 4, so that the entire simple circuit corresponds to the positive output terminal 21 from the meter M to the switch element. A meter drive current flows through the combined resistance from the resistance to the uppermost resistance (for example, when the switch element S4 is in the ON state, the combined resistance composed of the resistances R1 to R4), the switch element, and the negative output terminal 23, and this meter The drive current is uniquely determined by the resistance value of the combined resistance. On the other hand, in the double ON operation pattern, in the simple circuit shown in FIG. 4, the current flows only in the upper switch element of the two switch elements in the ON state. To the positive side output terminal 21, a combined resistance from the resistance corresponding to the upper switch element to the uppermost resistance (for example, when the switch elements S3 and S4 are in the ON state, a combined resistance composed of the resistors R1 to R3), the upper side. The meter drive current flows through the switch element and the negative output terminal 23, and this meter drive current is also uniquely determined by the resistance value of the combined resistance. Therefore, the combined resistance when the two switch elements are turned on can be represented by the following Table 1. In addition,
It goes without saying that the meter M may be either analog or digital type.

[0022]

[Table 1]

Returning to the circuit shown in FIG. 2, the description will be continued.

The circuit shown in FIG. 2 includes, in addition to the liquid level detection circuit 101, a remaining amount warning circuit 102 for warning that the amount of remaining liquid in the liquid container 1 is low. . The remaining amount warning circuit 102 includes an operational amplifier 24 and an enhancement type MOSFET 25, and the input side of the operational amplifier 24 has a Hall IC 5 _n-1 located at a liquid level that should warn that the remaining amount is small. Corresponding resistor 20 _n-1 and upper resistor 2
The connection point 26 to 0 _n-2 and the negative side output terminal 23 are connected, and the output side of the operational amplifier 24 is a MOSFET.
It is connected to 25 gates. In addition, the output terminal 27,
A warning means (not shown) such as a warning light is connected to the device 28.

In the remaining amount warning circuit 102, when the remaining amount of the liquid in the cylindrical portion 3 is large, no current flows through the resistance between the inputs of the operational amplifier 24, so that the output of the operational amplifier 24 becomes Lo level. Therefore, the MOSFET 25 is kept in the off state, and the driving current does not flow to the warning means, and the warning operation is not performed. On the other hand, the remaining amount of liquid inside the tubular portion 3 becomes small, and the Hall IC 5 _n-1
When is turned on, a current flows through the resistor 20 _n-1 and a voltage is generated between the inputs of the operational amplifier 24. Therefore, the output of the operational amplifier 24 is inverted to the Hi level, so that the MOSFET 25 is switched to the on state and a warning is issued. A driving current flows through the means, and warning operation such as lighting of a warning lamp is performed.

As described above, according to the first embodiment
The liquid level detection device 100 follows the change of the liquid level and moves up.
The float 8 that is allowed to move downward and the float 8
The permanent magnet 10 fixedly arranged at a predetermined position and the liquid container 1
Is fixedly arranged along the vertical direction on the substrate 4 arranged on the side.
Hall IC5 consisting of many₁ ~ 5_n And each,
Permanent magnet 10 that moves up and down as the float 8 moves up and down
Is arranged so that it can face the
Hall IC5 that is turned on electrically₁ ~ 5 _n And many
Number of Hall IC5₁ ~ 5_n Hall ICs on the output side of
5₁ ~ 5_n And a resistor 20 provided in a one-to-one correspondence with₁ ~
20_n And a series resistance circuit 20 configured by connecting in series
Prepared, one Hall IC5 with liquid level change₁ ~ 5_n or
Is a plurality of Hall ICs that are vertically adjacent to each other₁ ~ 5_n Is o
Hall IC5 in ON state when in ON state₁ ~ 5
_n Hall IC5 at the top of the₁ ~ 5_n Resistance corresponding to
20₁ ~ 20_n From multiple Hall IC5₁ ~ 5_n The entire
Hall IC5 at the top of the₁ Resistance 20 facing₁ Well
Current is applied to the combined resistance at
To detect the liquid level. For this reason,
According to the liquid level detection device 100 according to the first embodiment,
Liquid level and combined resistance current amount using the permanent magnet 10 of
Since and can be corresponded to one to one almost,
The dead zone at the time of bell drop is eliminated and the circuit is simplified.
It

Further, since the Hall ICs 5 _{1 to} 5 _n are one-side magnetic field operating Hall ICs that operate when the S pole or N pole of the permanent magnet 10 approaches, the Hall ICs 5 _{1 to} 5 5 that are in the ON state redundantly. The number of _n can be suppressed to a minimum of two, and the liquid level section which is in the ON state due to overlap can be suppressed to a small value.

In addition, the remaining amount warning circuit 1 is connected to the series resistance circuit 20.
Since 02 is connected, the remaining amount warning circuit 102 does not have to be provided separately and independently from the liquid level detection circuit 101, and the entire circuit can be simplified.

FIG. 6 shows an attachment state diagram and a wiring diagram of the liquid level detection device 100 according to the second embodiment.

Liquid level detection device 100 according to the second embodiment
As shown in FIG. 6 (A), is a liquid level detecting device 100 for detecting the liquid level of the liquid in the liquid container 1 so-called saddle type tank having a plurality of recesses 1d on the same horizontal plane, and the first embodiment The liquid level detecting device 100 configured similarly to the liquid level detecting device 100 according to the embodiment is installed in each recess 1d, and as shown in FIG.
The series resistance circuit 20 of 0 is connected in series and is connected to the meter M.

In the liquid surface detecting device 100 according to the second embodiment, each liquid surface detecting device 100 has a corresponding recess 1.
The liquid level of the liquid in d is detected, and different from the liquid level detection device 100 according to the first embodiment, different Hall ICs 5 _{1 to} 5 _n are turned on according to the liquid level, and this is turned on. The resistance value of the combined resistance of the series resistance circuit 20 changes according to the Hall ICs 5 _{1 to} 5 _n . Then, the meter drive current is determined by the resistance value of the total combined resistance obtained by adding the combined resistances of the liquid level detection devices 100.

Therefore, according to the liquid level detecting device 100 of the second embodiment, even if the saddle type tank 1 tilts and a difference occurs in the liquid level of the liquid in each recess 1d, the meter driving current is generated. The value can be substantially the same as the value when the saddle-shaped tank 1 is in the horizontal state, and the fluctuation of the display part such as the pointer of the meter M can be suppressed.

[0033]

According to the present invention, it is possible to eliminate the dead zone when the liquid surface level is lowered and to simplify the circuit.

[Brief description of drawings]

1A and 1B are a vertical sectional view and a horizontal sectional view (a sectional view taken along the line BB in FIG. 1A) of a liquid level detection device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of the liquid level detection device.

FIG. 3 is a circuit diagram of a Hall IC.

FIG. 4 is a simplified circuit diagram for easily explaining the circuit operation of FIG.

5 is a timing chart for explaining the circuit operation of FIG.

6A and 6B are a mounting state diagram and a wiring diagram of a liquid level detection device according to a second embodiment.

[Explanation of symbols]

100 liquid level detection device 1 liquid container 1d recess 4 substrate 5 ₁ to 5 _n Hall IC 8 float 10 permanent magnet 20 series resistor circuit 20 ₁ to 20 _n resistor 102 remaining amount warning circuit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tatsuo Hamano             5-22 22 Kanayama, Naka-ku, Nagoya-shi, Aichi             Inside Yajima Industry Co., Ltd. (72) Inventor Mitsuo Ukai             5-22 22 Kanayama, Naka-ku, Nagoya-shi, Aichi             Inside Yajima Industry Co., Ltd. (72) Inventor Toshihiko Itoigawa             5-22 22 Kanayama, Naka-ku, Nagoya-shi, Aichi             Inside Yajima Industry Co., Ltd. F term (reference) 2F013 AA05 BC02 CA18 CA21 CB01

Claims (4)

[Claims] 1. A float that is allowed to move in the vertical direction following a change in liquid level, a permanent magnet fixedly arranged at a predetermined position of the float, and a float on a substrate arranged on the liquid container side. A plurality of Hall ICs fixedly arranged along a direction, each of which is arranged so as to be opposed to a permanent magnet that moves up and down as the float moves up and down, and is electrically turned on when substantially facing the permanent magnet. Hall ICs, and each Hall IC on the output side of the multiple Hall ICs
A series resistance circuit configured by connecting resistances provided corresponding to pair 1 in series is provided, and one Hall IC or a plurality of Hall ICs vertically adjacent to each other is in an ON state due to a change in liquid level. At this time, a current is caused to flow through a combined resistance from the resistance corresponding to the uppermost Hall IC of the Hall ICs in the ON state to the resistance facing the uppermost Hall IC of all the plurality of Hall ICs. A liquid level detection device characterized by detecting the liquid level based on the amount of electric current. 2. The liquid level detection device according to claim 1, wherein the Hall IC is a one-side magnetic field operation Hall IC that operates when the S pole or the N pole of the permanent magnet approaches. 3. The liquid level detection device according to claim 1, wherein a remaining amount warning circuit is connected to the series resistance circuit. 4. The float, the permanent magnet, and the large number of Hall ICs are arranged in the respective concave portions of a liquid container having a plurality of concave portions on the same horizontal plane, and one pair is provided for a large number of Hall ICs for each concave portion. 1 is provided with the series resistance circuit and the plurality of series resistance circuits are connected in series, and is a total combined resistance of the whole plurality of series resistance circuits,
A current is caused to flow through the total combined resistance obtained by combining the individual combined resistances in the series resistance circuit for each recess in a plurality of series resistance circuits, and the liquid level is detected by the current amount of the total combined resistance. The liquid level detection device according to claim 1, 2, or 3.