JPH09152370A - Liquid level sensor and tank with sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly detect the quantity of a liquid at the inside even when a tank is tilted. SOLUTION: A cap 20 which is attached to the surface of a tank case 11 supports an interlocking member 40 so as to be movable up and down in a prescribed range, and a float is connected to the lower end of the interlocking member by a universal coupling 10 so as to be tiltable in many directions. In addition, a terminal metal fitting 50 by which a continuity state is changed over from an open state to a closed state when the interlocking member 40 is moved to the lowermost part is provided between the interlocking member 40 and the cap 20, and the continuity state can be connected electrically to the outside by a connector hood 40 installed at the cap 20. Even when a liquid level is tilted together with a tank 10, the float 30 follows a liquid level by its tilting operation so as not to be moved up and down as long as the quantity of a liquid is not changed, the continuity state of the terminal metal fitting is kept constant, and the liquid level can be detected correctly.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a liquid level sensor and a tank with a sensor.

[0002]

2. Description of the Related Art Conventionally, as this type of liquid level sensor, for example, one disclosed in JP-A-61-3013 is known. In FIG. 6, a liquid level sensor 2 attached to a tank case 1 has a rod-shaped upper and lower member 3 penetrating through a vertically penetrating through hole 2a, and a float 4 is supported at the lower end thereof, and a float 4 is supported at the upper end thereof. Has a contact sheet metal 5 attached thereto. Further, the upper and lower members 3 are longer than the through holes 2a and can be moved up and down by that amount, and when the upper and lower members 3 are located at the lowermost portion as shown in FIG. And the switch circuit 6 provided on the contact sheet metal 5 is changed from the open state to the closed state.

When the liquid level in the tank drops, the float 4
At the same time, the upper and lower members 3 are lowered to the lowermost position to close the switch circuit 6, and the lowering of the liquid level can be detected by an external indicator connected to the switch circuit.

[0004]

In the above-mentioned conventional liquid level sensor 2, as shown in FIG. 8, when the tank is tilted, the distance between the liquid level sensor 2 and the liquid surface facing directly below it changes, It was detected as if the amount of liquid in the tank had changed, and the accuracy of the detection result was a problem. For example, when a tank is used as a reservoir tank for brake fluid loaded on a vehicle or the like, when traveling on a sloping ground, it stores a regular amount of fluid in the tank,
In some cases, insufficient liquid volume was detected.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid level sensor and a tank with a sensor capable of accurately detecting the amount of liquid inside even if the tank is tilted.

[0006]

[Means for Solving the Problems and Functions / Effects]

<Invention of Claim 1> In order to achieve the above object, Claim 1
The invention according to, comprising a float that moves according to the liquid level of the liquid stored in the tank, in the one that detects the liquid level according to the position of the interlocking member that is connected to this float and moves in a predetermined direction, the float is It is characterized in that it is connected to the interlocking member so as to be tiltable in a direction different from its moving direction. <Invention of Claim 2> The invention according to Claim 2 is characterized in that, in the liquid surface sensor according to Claim 1, the float is connected to the interlocking member via a universal joint. <Invention of Claim 3> Further, in the invention according to Claim 3, in the liquid level sensor according to Claim 1 or 2, the interlocking member can be attached to the opening of the upper surface of the tank and the interlocking member in the vertical direction. A cap that movably supports is provided, and a connector portion provided with a pair of terminal fittings is integrally provided on the cap, and the movable contact comes into contact with the terminal fitting according to the movement of the interlocking member. It is characterized by <Invention of Claim 4> Furthermore, the invention according to Claim 4 is provided with a float that moves according to the liquid level of the liquid stored in the tank, and is located at the position of the interlocking member that is connected to this float and moves in a predetermined direction. In the tank provided with the liquid level sensor for detecting the liquid level accordingly, the float is characterized in that it is connected to the interlocking member so as to be tiltable in a direction different from the moving direction thereof.

According to the first or fourth aspect of the invention, the float tilts in accordance with the relatively inclined liquid surface in the tank, and the support portion of the float in the interlocking member is always connected to the liquid surface in a normal line. It will be. By the way, since the distance between the point and the surface is the length of the normal line dropped from the point to the surface, the support portion of the interlocking member on the normal line of the liquid surface is always at the liquid level height (liquid level). It is possible to detect the increase and decrease of the liquid amount without any influence on the inclination of the liquid surface. Therefore, even if the same liquid level sensor is used for a tank of a vehicle, for example, there is no lack of accuracy in detecting the liquid level during traveling on a sloping ground as in the conventional case. According to the second aspect of the present invention, it is possible to easily realize a mechanism that causes the float to follow the liquid surface even when the tank is tilted in multiple directions.
Therefore, when used in a vehicle or the like, accuracy of liquid level detection is not limited to when the vehicle leans forward and backward, and when the vehicle leans left and right.

According to the third aspect, since the liquid level sensor and the connector are unitized in the cap,
By removing the mating connector fitted to the connector section and removing the cap from the tank, the entire unit can be taken out and maintenance work can be easily performed. Moreover, since the switch of the liquid level sensor is constructed by using the terminal fittings of the connector portion, there is an advantage that the structure of the entire unit is simplified.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to, for example, a vehicle brake fluid reservoir tank will be described below with reference to FIGS. As shown in FIG. 1, the tank 10 includes a tank case 11 that stores brake oil.
And a cap 20 capable of covering the opening formed on the upper surface of the tank case 11, and the cap 20 has a liquid level sensor for detecting the liquid level by a float 30 that moves according to the liquid level. There is.

As shown in FIG. 4, the tank case 11 is formed in a rectangular parallelepiped shape having a rectangular cross section, and has a circular opening 12 having the same diameter as the width of the upper surface wall. A cylindrical projecting portion 13 is provided on the periphery of the opening 12 and a male screw is formed on the outer peripheral surface thereof so as to be screwed with the cap 20. The cap 20 is formed in the shape of a cylindrical container larger than the protruding portion 13, and has an internal peripheral wall surface formed with a female screw that is screwed into the male screw, and its bottom (hereinafter, because it is located above, A through hole 22 is formed in the center of the upper wall 21 ″), and an interlocking member 40 that is connected to the float 30 can be inserted therethrough.

On the upper surface side of the upper wall 21, a wiring portion is projected and a pair of terminal fittings 50 are housed therein. A rectangular tubular connector hood 24 that opens laterally in a hood shape is integrally formed at the end of the upper surface wall 21 in the wiring portion, and a pair of terminal fittings 50 is provided therein. The terminal fitting 50 includes a male tab 51 and a fixed contact portion 52 extending to the opposite side thereof. The tab 51 is projected into the connector hood 24 and the fixed contact portion 52 is attached to the upper wall 2.
It is made to project in the cylindrical contact chamber 23 protrudingly provided at 1. A sub cap 25 is attached to the upper surface opening of the cylindrical contact chamber 23 so that the sub cap 25 does not come off even if the interlocking member 40 comes into contact therewith.

On the other hand, the interlocking member 40 is formed in a rod shape penetrating the inside of the through hole 22 and is movable in the axial direction without tilting. A circular plate 42, which is a movable contact having conductivity, is provided with a mounting clip 41 at the tip of the interlocking member 40.
When the interlocking member 40 is lowered to the lowermost part, the circular plate 42 short-circuits the fixed contact portions 52 of the pair of terminal fittings 50. Now, the float 30 is connected to the lower end side of the interlocking member 40 via a universal joint 60, and receives the buoyancy thereof. The universal joint 60 is configured such that a ball-shaped inner 62 freely slides and rotates in an outer 61. The outer 61 side is fixed to the lower end of the interlocking member 40, and the inner 62 side is the float described below. It is attached to the connecting rod 32 of 30.

The float 30 has a flat spherical shape with a short vertical dimension, and a connecting rod 32 erected on the upper side is connected to the lower end of the interlocking member 40 by the universal joint 60. The float 30 is formed into a flat sphere to have stability on the liquid surface, and the lower surface side is heavier than the upper surface side, so that the connecting rod 32 is in an upright posture on the liquid surface.
Further, the buoyancy of the float 30 is balanced with the weight of the connecting rods 32 in the upright posture so that the liquid surface is located at the center of the main body and is in an equilibrium state. Next, the operation of this embodiment having the above configuration will be described. The vehicle does not always travel on a flat road, but sometimes travels on an inclined surface. At this time, the tank 10 tilts together with the vehicle, and the liquid level in the tank relatively tilts as shown in FIG. Then, the float 30 tilts with the universal joint 60 as a fulcrum, and the float 30 is in a vertical posture with respect to the liquid surface, and the own weight and the buoyancy force are balanced. Since the amount of liquid in the tank 10 does not increase or decrease, the universal joint 60 serving as a fulcrum is located at the same height and keeps the interlocking member 40 in the same state as when traveling on a flat road. Conventionally, since there is no tilting portion due to the universal joint 60, the float 30 is moved from the position shown by the chain double-dashed line in FIG.
Shows a drop in the liquid level even though the liquid level has not dropped, causing a short circuit between the fixed contact portions 52, but this is not the case with the liquid level sensor of the present embodiment. .

<Other Embodiments> The present invention is not limited to the above embodiments. For example, the following embodiments are also included in the technical scope of the present invention.
Other than the following, various modifications can be made without departing from the scope of the invention. (1) As shown in FIG. 5, the interlocking member 70 is movable up and down within the tubular portion of the upper wall of the tank case. The interlocking member 70 is formed in a dish shape with a concave wall 71 and has a short-circuit piece 73 on the upper side edge so as to short-circuit between the pair of terminal fittings 50 provided in the tank when positioned below. It has become. The float 75 is formed in a substantially hemispherical shape having a spherical surface on the lower surface side, and a connecting rod 77 erected on the upper side is connected to the concave wall 71 of the interlocking member 70. At the lowermost end of the concave wall 71, a through hole 72 is formed which spreads from the inner side to the outer side, and the distal end of the connecting rod 77 is penetrated therethrough, and a fastener 79 is attached to the distal end.
It is attached so that it does not come off. Also, the connecting rod 7
7, a lower surface side of the concave wall 71 is provided with a receiving surface wall 78 formed in a concave shape corresponding to the outer surface of the concave wall 71,
The concave wall 71 is sandwiched between the fastener 79 and the float 7
5 can be tilted in multiple directions. According to this structure, the interlocking member 70 can be formed compactly in the vertical direction, and it can be applied to a small tank in the vertical direction. (2) In the present embodiment, only when the liquid level is lowered is detected, but, for example, the interlocking member is connected to a differential transformer or the like to continuously detect the change in the liquid level. May be. (3) In this embodiment, the cap 2 is used as a unit.
Although the liquid level sensor is configured to 0, it is not always necessary to provide the liquid level sensor on the cap, and the liquid level sensor may be directly attached to the tank.
However, when the cap is provided as in the present embodiment, the assembling and maintenance are easy. Moreover, if the connector hood is provided as in this embodiment, the output of the liquid level sensor can be easily connected to the display circuit as in this embodiment.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tank including a liquid level sensor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which the tank is tilted and a float follows the tilt.

FIG. 3 is a cross-sectional view showing a state in which the liquid level in the tank is lowered.

4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a sectional view of a tank provided with a liquid level sensor having another structure of a tilting portion of a float as another embodiment.

FIG. 6 is a partial cross-sectional view showing a conventional liquid level sensor.

FIG. 7 is a partial cross-sectional view showing an operation of a conventional liquid level sensor due to a decrease in liquid level.

FIG. 8 is a schematic cross-sectional view showing the operation of a conventional liquid level sensor depending on the tank inclination.

[Explanation of symbols]

 10 ... Tank 11 ... Tank case 20 ... Cap 24 ... Connector 30 ... Float 40 ... Interlocking member 50 ... Terminal metal fitting 60 ... Universal joint

Claims (4)

[Claims] 1. A float comprising a float that moves according to a liquid level of a liquid stored in a tank, and detects the liquid level according to the position of an interlocking member that is connected to the float and moves in a predetermined direction. Is connected to the interlocking member so as to be tiltable in a direction different from the moving direction thereof. 2. The liquid level sensor according to claim 1, wherein the float is connected to the interlocking member via a universal joint. 3. A cap that can be attached to an opening on the upper surface of the tank and that supports the interlocking member so as to be movable in the vertical direction is integrally provided with a connector portion provided with a pair of terminal fittings. The liquid level sensor according to claim 1 or 2, wherein the movable contact contacts the terminal fitting according to the movement of the interlocking member. 4. A float provided with a liquid that moves according to the liquid level of the liquid stored in the tank, and a liquid level sensor that detects the liquid level according to the position of an interlocking member that is connected to the float and moves in a predetermined direction. In the above tank, the float is connected to the interlocking member so as to be tiltable in a direction different from the moving direction thereof.