JP2001343275A - Liquid level detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detecting device which can attach a circuit board precisely to a prescribed position of a main body flame. SOLUTION: This liquid level detecting device is equipped with a float arm 2 provided with a float which floats on a liquid surface, an arm holder 4 for holding the float arm 2, the main body flame 3 which is equipped wit the arm holder 4 pivotally, a circuit board 7 which is accommodated and fixed in a recessed part 43 of the flame 3 and has at least two parallel sides facing with each other, and a contact holding member 5 which has a slide contact 6 sliding on the circuit board 7 and is fixed to the arm holder 4. Plural protruding parts 24 against which one side 51 of the circuit board 7 abuts are disposed on a wall 44 forming the recessed part 43 of the flame 3. A trench part 25 is formed along the wall 44 on which the protruding parts 24 are formed. Elastic segments 47, 48 which abut against one side 52 parallel to the other side 51 of the circuit board 7 and press it against the protruding parts 24 side are installed in the flame 3.

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 fixing structure of a liquid level detecting device provided with a float.

[0002]

2. Description of the Related Art A conventional liquid level detecting device 1 is disclosed in
No. 029, and as shown in FIGS.
A float arm 2 provided with a float (not shown) that moves due to a change in the liquid level is attached to the body frame 3 so as to be rotatable.

[0003] The float arm 2 is rotatably supported by the main body frame 3 via an arm holder 4 which moves with the rotation of the float arm 2.

[0004] A contact holding member 5 is fixed to the arm holder 4, and a sliding contact 6 protrudes from the tip of the contact holding member 5. A pair of holding pieces 4a are formed on the upper part of the arm holder 4 for positioning the float arm 2 and the contact holding member 5 held by the arm holder 4, and the inner shape of the holding piece 4a is floated. The float arm 2 is formed into an arc surface so as to conform to the outer surface shape of the arm 2 and press-fits the float arm 2 into the arc surface while pushing and expanding the holding piece 4a from the upper open portion of the holding piece 4a. The arm 2 is configured not to come out upward.

The sliding contact 6 slides on a circuit board 7 made of ceramic provided on the main body frame 3 with a predetermined contact pressure.

The circuit board 7 has a band-shaped resistor (not shown) on its surface and comb-shaped electrodes (not shown) arranged along the band-shaped resistor. A predetermined contact is provided on the comb-shaped electrode. The sliding contact 6 is slid to ground by pressure, a current change corresponding to a variable resistance between the sliding contact 6 and the base end of the resistor is output, and the liquid amount is detected. The two sides of the circuit board 7 are in contact with the wall 3a provided on the other side, and the other two sides parallel to each of the two sides are made of an elastic piece 3b having a locking claw 3c.
It is fixed by pressing against the side.

Further, a bearing fitting portion 8 is formed on the main body frame 3, and a two-stage cylindrical bearing member 9 having a different diameter is rotatably fitted into the bearing fitting portion 8. The base of the arm holder 4 and the contact holding member 5 is superimposed on it, and the float arm 2 is inserted into the shaft hole 10 provided in the bearing member 9 and the shaft hole 11 provided in the base of the arm holder 4 in a direction substantially perpendicular to L.
The end 12 bent in the shape of a letter is inserted through the end 12
A push nut as a slip-off preventing member 13 is press-fitted into the through-end portion 12a that protrudes from the lower surface of the bearing member 9, and the float arm 2 is pulled down by the press-fitting of the push nut 13 to be crimped.

Reference numerals 14 and 15 denote terminals. One terminal 14 is connected to the circuit board 7, and the other terminal 15 is connected to the contact holding member 5 via a coil spring 16.

[0009]

However, in the case of such a liquid level detecting device, for example, in the process of dividing the motherboard of the circuit board to form the circuit board 7, burrs or the like are generated on the end face of the circuit board 7. When fixing the circuit board 7 to the main body frame 3, the burrs or the like hit the wall 3a, so that the mounting position is shifted and the circuit board 7 cannot be mounted at a proper position. That is, there is a concern that it is not possible to output an accurate current change corresponding to the variable resistance between the sliding contact 6 and the base end of the resistor.

[0010] The present invention has been made in view of this point,
A main object of the present invention is to provide a liquid level detecting device capable of accurately assembling a circuit board at a predetermined position of a main body frame.

[0011]

In order to achieve the above object, the present invention provides a float arm having a float floating on a liquid surface, an arm holder for holding the float arm, and a rotatable arm holder. A main body frame, a circuit board having at least two opposing sides parallel to each other and housed and fixed in a recess of the main body frame, and a contact fixed to the arm holder having a sliding contact sliding on the circuit board. A liquid level detecting device provided with a holding member, wherein a plurality of protrusions on one side of the circuit board are provided on a wall forming the recess of the main body frame, and a groove is formed along the wall on which the protrusion is provided. And an elastic piece is provided on the main body frame to contact the other side parallel to the one side of the circuit board and press the circuit board toward the protrusion.

Also, a float arm having a float floating on the liquid surface, an arm holder holding the float arm and having two shaft portions at a pivot point, and supporting the shaft portions of the arm holder respectively. A main body frame rotatably held by two spaced bearings, a circuit board having at least two opposing sides parallel to each other and housed and fixed in a concave portion of the main body frame; and a slide sliding on the circuit board. In a liquid level detection device having a contact holding member fixed to the arm holder and having a contact, a plurality of protrusions are provided on a wall of the main body frame that forms the recess, with one side of the circuit board abutting. An elastic piece is provided along the wall on which the protrusion is provided, and an elastic piece is provided on the body frame to abut on the other side parallel to the one side of the circuit board and press the circuit board toward the protrusion. Those digits.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid level detecting device 1 according to the present invention includes a float arm 2 having a float floating on a liquid surface, and a shaft portion 17 which holds the float arm 2 and is a fulcrum of rotation of the float arm 2. The main body frame 3 including the arm holder 4 provided, the two bearings 18 and 19 that support the shaft 17 of the arm holder 4, the circuit board 7 fixed to the main body frame 3, and the circuit board 7. And a contact holding member 5 having a sliding contact 6 to be slid and fixed to the arm holder 4. With this configuration, it is possible to provide the liquid level detection device 1 that can mount the circuit board 7 at a predetermined position of the main body frame 3.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show one embodiment of the present invention. The same and corresponding parts as those in the conventional example are denoted by the same reference numerals, and detailed description thereof will be omitted.

An example in which the present invention is applied to a liquid level detecting device 1 for a vehicle such as an automobile will be described. Liquid level detecting device 1 of the present invention
A float arm 2 interlocked with a float (not shown) floating on the liquid surface of a fuel tank (not shown), an arm holder 4 that moves with the rotation of the float arm 2, and a shaft 2 that supports a shaft 17 of the arm holder 4. A main body frame 3 having two bearing portions 18 and 19, a circuit board 7 fixed to the main body frame 3, and a sliding contact 6 sliding on the circuit board 7 are fixed to the arm holder 4. Contact holding member 5
And a terminal 20 electrically connected to the circuit board 7, and a lead wire 2 connecting the terminal 20 to an external circuit (not shown).
The sliding contact 6 slides on the circuit board 7 via the float, the float arm 2 and the arm holder 4 as the liquid level fluctuates, so that a resistor (not shown) provided on the circuit board 7 The resulting voltage fluctuations are
This is output to an external circuit (not shown).

The float arm 2 is in the form of a metal rod, and has a not-shown float at the end thereof which floats on the liquid surface. The other end 12 is bent.

The arm holder 4 is made of synthetic resin and has a holding portion 23 having a hole 22 through which the bent end portion 12 of the float arm 2 penetrates.
Is provided from both sides. The float arm 2 is positioned and fixed to the arm holder 4 by the holding portion 23 and the holding piece 4a.

Further, there is provided a shaft portion 17 which is positioned at two positions with the body portion 26 interposed therebetween, and this shaft portion 17 is provided on the arm holder 4.
Are formed at both ends on the same axis, and the body portion 26 and the shaft portion 17 are cylindrical with a hole 27 penetrating at the center thereof. This shaft portion 17 is a pivot of the float arm 2. Further, a contact holding member 5 having two sliding contacts 6 sliding on the circuit board 7 is fixed to the arm holder 4. The contact holding member 5 and the sliding contact 6 are made of metal, and the sliding contact 6 is fixed to the contact holding member 5 by caulking, and the contact holding member 5 is fixed to the arm holder 4 by a heat welding portion 4b. The sliding contact 6 may be formed by pressing the contact holding member 5 by pressing.

To assemble the float arm 2 to the arm holder 4, the end 12 of the float arm 2 is inserted into the hole 22 of the holding part 23, and the shaft of the end 12 held rotatably by the holding part 23 is connected. The rotation of the float arm 2 is prevented by rotating the shaft portion 17 about the center in the axial direction and elastically deforming the holding piece 4 a of the arm holder 4 to hold the float arm 2. By assembling as described above,
The float arm 2 can be easily assembled to the arm holder 4.

The main body frame 3 is made of a synthetic resin, and includes two frame members 28 and 29. Each of the frame members 28 and 29 is provided with an arm holder 4 for pivotally supporting the arm holder 4.
The bearing portions 18 and 19 for receiving the shaft portion 17 are provided.

The frame member 28 is provided with four elastic pieces 31 each having a locking claw 30, and the other frame member 29 has a locking portion 32 with which the locking claw 30 is engaged. Four are provided. The frame member 29 has two pins 33 protruding therefrom.
8 is provided with a hole 34 through which the pin 33 passes. The frame members 28 and 29 are assembled and fixed by engaging the locking claws 30 and the locking portions 32 provided on the frame members 28 and 29, respectively, and joining the ends of the pins 33 exposed from the holes 34 by heat welding. It is completed by deforming. In addition,
Reference numeral 35 denotes a positioning pin provided in the frame member 29, which is positioned in the positioning hole 36 provided in the frame member 28 to position the frame members 28 and 29. Reference numeral 37 denotes a window provided in the frame member 28, and exposes a part of the float arm 2 and the arm holder 4.

The frame structure 29 has a notch 38 whose part is cut out. This notch 38
At both ends, there are provided abutting portions 39 and 40 which abut against the float arm 2 and regulate the rotation range. Note that the arm holder 4 is not the float arm 2 but the contact portions 39 and 40.
To limit the rotation range. The notch 38 is provided between the frame component 28 and the frame component 2.
9 constitutes the guide portion 41. Since the movement of the float arm 2 in the rotation axis direction is suppressed by the guide portion 41, it is possible to prevent the float arm 2 from coming off the holding piece 4a.

The circuit board 7 is made of ceramic, and has two sets of opposing rectangular sides parallel to each other, and has a conductor 42 and a resistor (not shown) on its surface. This circuit board 7 is fixed to a frame structure 29. Frame structure 29
A concave portion 43 for accommodating the circuit board 7, a wall 44 forming a peripheral wall of the concave portion 43, and a protrusion 24 that contacts the circuit board 7 are appropriately provided inside the wall 44.
A groove 25 is formed along the line of FIG. By providing the projections 24 and the grooves 25, the circuit board 7 can be securely fixed at a predetermined position of the frame structure 29 constituting the main body frame 3 even when burrs or the like occur on the end face of the circuit board 7. Can be.

Further, the elastic piece 4 having locking claws 45, 46 for locking on opposing sides of the rectangular circuit board 7, respectively.
7 and 48, and one side 51 of the circuit board 7 is brought into contact with the projection 24 by the elastic pieces 47 and 48 having the locking claws 45 and 46. 51
The other side 52 parallel to the main body 3 can be pressed toward the protrusion 24 by the elastic pieces 47 and 48, and the circuit board 7 can be fixed without falling off from the main body frame 3. That is, the voltage fluctuation caused by the resistor (not shown) of the circuit board 7 can be reliably output, and the merchantability can be improved.

The terminal 20 is made of metal and is formed by bending a plate-like member. The terminal 20 is a resilient contact piece 20 a that comes into contact with a land (not shown) of the circuit board 7.
It has. The distal end of the contact piece 20a has a structure that branches into two and reliably contacts the circuit board 7 at two points.

Reference numeral 20b denotes a stopper for preventing the terminal 20 from being detached from the main body frame 3, which is locked by a locking portion 49 provided on the frame structure 29 so that the terminal 20 connected to the circuit board 7 does not come off. 20c is the conductive wire 2 of the lead wire 21.
A first fixing portion for fixing the portion 1a and electrically connecting the terminal 20 to the terminal 20, and a second fixing portion 20d for fixing the covering portion 21b of the lead wire 21, which deforms both the first and second fixing portions. Is fixed. With such a configuration, the terminal 20 can be connected to an external circuit (not shown), and the terminal 20 can be electrically connected to the lead wire 21 without using solder.

The connection between the terminal 20 and the circuit board 7 is performed by mounting the circuit board 7 on the main body frame 3 in advance and connecting the terminal 20 to the terminal accommodating portion 50 provided on the main body frame 3 in the direction of arrow C in FIG. insert. As a result, it is possible to easily connect without using solder, and it is possible to reduce work labor,
An inexpensive liquid level detection device can be provided.

In this embodiment, the circuit board 7 is rectangular, but may be square. Further, a trapezoid may be used as long as at least two opposing sides are parallel. Further, the support structure of the arm holder 4 to the main body frame 3 is not limited to the above-described embodiment, and may be freely set as appropriate.

[0029]

As described above, according to the present invention, it is possible to provide a liquid level detecting device which can achieve the intended purpose and can accurately assemble a circuit board at a predetermined position of a main body frame. .

[Brief description of the drawings]

FIG. 1 is a top view of one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a sectional view taken along line BB in FIG. 1;

FIG. 4 is a top view of the embodiment with the frame structure removed.

FIG. 5 is a top view of a conventional example.

FIG. 6 is a sectional view taken along line DD in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid-level detection apparatus 2 Float arm 3 Main frame 4 Arm holder 4a Holding piece 5 Contact holding member 6 Sliding contact 7 Circuit board 12 End part 17 Shaft part 18, 19 Bearing part 20 Terminal 23 Holding part 24 Projection 25 Groove 28 , 29 Frame component 43 Recess 44 Wall 47, 48 Elastic piece 51 One side 52 Other one side

Claims (2)

[Claims] 1. A float arm having a float floating on a liquid surface, an arm holder for holding the float arm, a main body frame rotatably provided with the arm holder, and housed and fixed in a recess of the main body frame. A liquid substrate having at least two opposing sides parallel to each other, and a contact holding member having sliding contacts that slide on the circuit board and fixed to the arm holder. A plurality of protrusions are provided on a wall forming the recess of the frame so that one side of the circuit board abuts, a groove is provided along a wall provided with the protrusion, and the one side of the circuit board is provided on the main body frame. A liquid surface detecting device provided with an elastic piece which abuts on the other side parallel to the above and presses the circuit board toward the protrusion. 2. A float arm having a float floating on a liquid surface, an arm holder holding the float arm and having two shaft portions at a pivot point, and each supporting a shaft portion of the arm holder. A main body frame rotatably held by two spaced bearings, a circuit board having at least two opposing sides parallel to each other and housed and fixed in a concave portion of the main body frame; and a slide sliding on the circuit board. In a liquid level detection device having a contact holding member fixed to the arm holder and having a contact, a plurality of protrusions are provided on a wall of the main body frame that forms the recess, with one side of the circuit board abutting. Providing a groove along the wall provided with the protrusion,
A liquid level detecting device, wherein an elastic piece is provided on the main body frame to abut on the other side parallel to the one side of the circuit board and press the circuit board toward the protrusion.