JP2001343276A - Liquid level detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detecting device which can reduce the number of components and energize surely. 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 which holds the float arm 2 and is provided with a shaft part as the pivoting fulcrum of the float arm 2, a flame 3 which supports pivotally the shaft part of the arm holder 4, a circuit board 7 fixed to the flame 3, and a sliding member 61 which has collectively a slide contact 60 sliding on the circuit board 7 and is fixed to the arm holder 4. An arm segment 62 which stretch toward the circuit board 7 side without an end is installed in the sliding member 61, and the sliding contact 60 is installed on the arm segment 62.

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 provided in a fuel tank of a vehicle or the like, and more particularly to a liquid level detecting device characterized by sliding contacts sliding on a circuit board. is there.

[0002]

2. Description of the Related Art A conventional liquid level detecting device 1 is disclosed in
No. 029, and as shown in FIGS. 11 and 12, a float arm 2 having a float (not shown) attached to the tip which moves due to fluctuations in the liquid level can be pivoted to the main body frame 3 via an arm holder 4. To support.

[0003] A contact holding member 5 is fixed to an arm holder 4, and a sliding contact 6 is provided at the tip of the contact holding member 5 by caulking. 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 holding piece 4a is held from the upper open portion of the holding piece 4a. The float arm 2 is press-fitted while pushing the piece 4a, and the holding piece 4a
The float arm 2 is configured not to come out upward in FIG. 12 due to the elastic restoring force.

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, and a sliding contact is provided on the comb-shaped electrode. 6 is slidably grounded, and outputs a voltage variation corresponding to a variable resistance between the sliding contact 6 and the base end of the resistor to detect the liquid amount.

In such a liquid level detecting device 1, the bearing structure of the float arm 2 is such that a bearing fitting portion 8 is formed in the main body frame 3, and a two-stage cylindrical bearing having a different diameter is formed on the bearing fitting portion 8. The member 9 is rotatably fitted, and the bearing member 9, the arm holder 4 and the contact holding member 5 are overlapped with each other.
The end 12 obtained by bending the float arm 2 into an L-shape in a substantially right angle direction is inserted through the shaft hole 10 provided in the arm holder 4 and the shaft hole 11 provided in the base of the arm holder 4. A protrusion preventing member 13 is provided on the protruding penetrating end 12a.
And press-fit the push nut.

[0007] A flange-shaped engaging portion 14 formed by header processing on the outer periphery of the float arm 2 in the middle of the end portion 12 thereof.
The receiving surface 15 is formed at the edge of the shaft hole 11 of the arm holder 4, and the contact surface 16 is formed at a position where the bearing surface 9 contacts the bearing member 9. The arm holder 4 receives the locking portion 14 of the float arm 2 on the receiving surface 15 and assembles the float arm 2, the arm holder 4 and the contact holding member 5 so as not to rattle.

Therefore, when the push nut 13 is tightened, the locking portion 14 of the float arm 2 is received on the receiving surface 15,
The contact surface 16 of the arm holder 4 contacts the bearing member 9 and the bearing member 9 is fixed together with the arm holder 4 and the push nut 13 so that the float arm 2 and the bearing member 9 are joined together. It is a structure that rotates. Further, a force is always applied to the upper side of the arm holder 4 by a coil spring 17 electrically connected to the contact holding member 5. The upward force of the coil spring 17 is received by the stepped portion 8a of the bearing fitting portion 8 and the stepped portion 9a of the bearing member 9, so that the float arm 2 does not move upward together with the bearing member 9. Then, a part of the bearing member 9 projects from the main body frame 3, and the assembly of the float arm 2, the arm holder 4 and the bearing member 9 rotates with respect to the main body frame 3.

Reference numerals 18 and 19 denote terminals. One terminal 18 is connected to the circuit board 7, and the other terminal 19 is connected to the contact holding member 5 via the coil spring 17.

[0010]

In recent years, the liquid level detecting device 1 and the fuel pump, etc., provided in a fuel tank (not shown) are provided in the fuel tank as a combined unit. Due to the assembly problem associated with the unitization, the liquid level detection device 1 is also desired to be downsized. In the liquid level detecting device of the related art, since the sliding contact 6 is fixed to the contact holding member 5 by caulking, the number of components is large, and it is difficult to reduce the cost. In addition, since the fixing structure using the swaging is adopted, there is a limit in reducing the size of the liquid level detecting device. In addition, the conventional sliding contact 6
In this case, since the point of contact with the circuit board 7 is one point, if a foreign object is interposed between the sliding contact 6 and the circuit board 7,
There is a possibility that a current supply failure may occur. Therefore, an object of the present invention is to provide a liquid level detection device capable of reducing the number of components and performing reliable energization.

[0011]

In order to achieve the above object, the present invention provides a float arm having a float floating on a liquid surface, a shaft holding the float arm and serving as a pivot of the float arm. Arm holder, a frame supporting the shaft of the arm holder, a circuit board fixed to the frame, and a sliding contact sliding on the circuit board are integrally fixed to the arm holder. And a sliding member provided endlessly extending toward the circuit board, and the sliding contact is provided on the arm.

Also, a float arm having a float floating on the liquid surface, an arm holder holding the float arm and having a shaft serving as a pivot of the float arm, and a shaft of the arm holder A first frame having a first bearing portion for supporting, a second frame having a second bearing portion for supporting a shaft portion of the arm holder, a circuit board fixed to the first frame, A sliding member integrally having sliding contacts that slide on the circuit board and fixed to the arm holder, wherein the sliding member is provided with an arm piece extending endlessly toward the circuit board. The sliding contact is provided on the arm piece.

[0013] Further, a plurality of the sliding contacts are provided.

Further, the sliding contact is provided with a notch and divided into a plurality of parts.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid level detecting device according to the present invention includes a float arm 2 having a float floating on a liquid surface, and a shaft portion which holds the float arm 2 and is a pivot of the float arm 2. Arm holder 4 and arm holder 4
Frame 3, a circuit board 7 fixed to the frame 3, and a sliding contact 60 sliding on the circuit board 7.
Member 61 integrally fixed to arm holder 4
A sliding member 61 is provided with an arm 62 extending endlessly toward the circuit board 7 side.
Is provided. With this configuration,
It is possible to provide a liquid level detecting device that can reduce the number of parts and can achieve cost reduction.
Further, by forming the sliding contact 60 and the sliding plate 61 as a sliding member integrally, a liquid level detecting device capable of achieving downsizing in the contact direction of the sliding contact 60 is provided. can do.

Further, a float arm 2 having a float floating on the liquid surface, an arm holder 4 holding a float arm 2 and having a shaft portion which is a pivot of the float arm 2 and a shaft portion of the arm holder 4 A first frame 29 provided with a first bearing portion 31 for supporting the shaft 24, and a second frame provided with a second bearing portion 30 for supporting the shaft portion 24 of the arm holder 4.
The frame includes a frame, a circuit board 7 fixed to the first frame 29, and a sliding member 61 integrally having a sliding contact 60 sliding on the circuit board 7 and fixed to the arm holder 4. An arm 62 extending endlessly toward the circuit board 7 is provided on a moving member 61, and a sliding contact 60 is provided on the arm 62. With such a configuration, it is possible to provide a liquid level detection device capable of reducing the number of components and achieving cost reduction. Also,
By forming the sliding contact 60 and the sliding plate 61 integrally,
It is possible to provide a liquid level detection device that can achieve downsizing in the contact direction of the sliding contact 60.

Further, a plurality of sliding contacts 60 are provided. With such a configuration, it is possible to provide a liquid level detection device capable of reliably energizing the sliding contact 60 and the circuit board 7. Further, the contact pressure of the sliding contact 60 can be reduced, and a liquid level detecting device with good sliding durability can be provided.

Further, the sliding contact 60 is provided with a notch 63 and is divided into a plurality of parts. With this configuration, the number of the sliding contacts 60 can be easily increased only by forming the notch 63, so that a liquid level detecting device that can be manufactured at low cost can be provided.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 10 show an 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.

The liquid level detecting device 1 of the present invention includes a float arm 2 linked to a float (not shown) floating on the liquid level of a fuel tank (not shown), an arm holder 4 which moves with the rotation of the float arm 2, and a The main body frame 3 rotatably supports the arm holder 4, a circuit board 7 fixed to the main body frame 3, and a sliding contact 60 sliding on the circuit board 7, and fixed to the arm holder 4. A sliding plate 61 serving as a sliding member, a terminal 20 electrically connected to the circuit board 7, and a lead wire 21 connecting the terminal 20 to an external circuit (not shown). In addition, the sliding contact 60 slides on the circuit board 7 via the float, the float arm 2 and the arm holder 4, so that a voltage change caused by a resistor (not shown) provided on the circuit board 7 is caused by the lead wire 21. , And outputs to an external circuit (not shown).

The float arm 2 is in the form of a metal rod and has the above-mentioned float floating on the liquid surface at its tip. 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 with a holding piece 4a having a C-shaped cross section. The holding piece 4a is open horizontally as shown in FIG. The float arm 2 is positioned and fixed to the arm holder 4 by the holding portion 23 and the holding piece 4a.

As shown in FIG. 6, the float arm 2 is assembled to the arm holder 4 in the direction of the arrow.
That is, the end portion 12 of the float arm 2 is inserted into the hole 22 of the holding portion 23, and at the same time, is inserted through the opening 4b of the holding piece 4a of the arm holder 4, and the holding piece 4a is elastically deformed so that the float arm 2 is Assembled in

Further, there is provided two shaft portions 24 which are spaced apart from each other with the body portion 26 of the arm holder 4 interposed therebetween.
Are formed at both ends on the same axis in the arm holder 4, and the body portion 26 and the shaft portion 24 are cylindrical with a hole 27 penetrating at the center thereof. This shaft portion 24 is a pivot of the float arm 2. Further, the arm holder 4 is fixed with a sliding plate 61 provided with two sets of sliding contacts 60 each of which includes three contacts and slides on the circuit board 7. The sliding contact 60 is an endless arm piece 6 extending from both sides.
2 is held on the sliding plate 61 by the sliding contact 60
The sliding contact 61 and the sliding plate 61 are made of metal, and the sliding contact 60 and the sliding plate 61 are integrally formed by press working, and the sliding plate 61 is fixed to the arm holder 4 by the heat welding portion 4b.
The sliding contact 60 has two notches 63 near the sliding contact 60 of the arm piece 62, and three sliding contacts 60 are formed for one set of the arm piece 62. Further, the sliding plate 61 is provided with a plate-like portion 64 along the holding arm piece 25 of the arm holder 4, and as shown in FIG. 9, the arm piece 62 bent rightward in FIG. This is for obtaining a predetermined contact pressure when the moving contact 60 comes into contact with the circuit board 7 and is elastically deformed. Although not shown, each of the sliding contacts 60 has a U-shaped cross section, and is in contact with the circuit board 7.

Although not employed in this embodiment, the shape of the plate-like portion 64 is changed to the shape of the hole 4 formed in the holding arm piece 25 of the arm holder 4 to form the holding piece 4a.
The sliding plate 61 and the arm holder 4 may be positioned so that a part of the plate-like portion 64 is fitted into the hole 4c.

By forming in this manner, it is possible to provide a liquid level detecting device capable of reliably energizing the sliding contact 60 and the circuit board 7. In addition, sliding contact 6
The contact pressure of 0 can be reduced, and a liquid level detecting device with good sliding durability can be provided. Further, the number of the sliding contacts 60 can be increased only by providing the notch 63 in the arm piece 62, so that the manufacturing can be performed at low cost.
The plurality of sliding contacts 60 are not formed only by the notches 63, but may be formed by providing an uneven portion by press working.

Further, since the sliding contact 60 and the sliding plate 61 are formed integrally, compared with the conventional liquid level detecting device,
The thickness of the shaft portion 24 of the sliding contact 60 and the sliding plate 61 in the axial direction can be suppressed, and a thinner liquid level detecting device 1 can be provided.

The float arm 2 and the sliding plate 61 are fixed to a holding arm 25 protruding from the body 26 of the arm holder 4. The holding arm 25 projects in a direction perpendicular to the axial direction of the shaft portion 24.

The main body frame 3 is also made of a synthetic resin.
It comprises a frame 29 and a second frame 28. The second frame 28 is flat and has a window 39 as shown in FIG.
Is to expose a part of it. The first frame 29 has a box shape in which the side surface for housing the circuit board 7 is surrounded by a wall and has a bottom, as shown in FIG. The first and second
Each of the frames 29 and 28 includes first and second bearing portions 31 and 30 for receiving the shaft portion 24 of the arm holder 4 to rotatably support the arm holder 4. The holding arm piece 25 of the arm holder 4 including the float arm 2 and the sliding plate 61 is located between the first and second bearing portions 31 and 30.

The second frame 28 is provided with four elastic pieces 33 provided with locking claws 32, and the first frame 29 is similarly provided with four locking portions 34 with which the locking claws 32 engage. Is provided. The first frame 29 has four pins 3
5a and 35b are formed in a protruding manner, and the second frame 28 has holes 36a through which the pins 35a and 35b pass.
36b are provided. Insert the pins 35a and 35b into the holes 36
These are welding fixing portions that are welded and fixed after insertion into a and 36b.

The pin 35a and the hole 36a also serve as a positioning member. Therefore, since the positioning member also serves as the welding fixing portion as the fixing means, there is no need to separately provide the positioning member and the welding fixing portion, and the first and second frames 29 and 28 can be made smaller. The pin 35b and the hole 36b are provided in the vicinity of contact portions 41 and 42 described later.

The first and second frames 29 and 28 are assembled and fixed by temporarily fixing the engaging claws 32 and the engaging portions 34 provided on the first and second frames 29 and 28 respectively. This is completed by deforming the ends of the pins 35a and 35b exposed from the 36a and 36b by heat welding.

A pin 37 and a hole 38 provided in the vicinity of the first and second bearing portions 31 and 30 constitute a concave and convex fitting portion, and the pin 37 is provided on the first frame 29 and the second frame 28
The positioning of the frames 28 and 29 is performed by inserting the first and second bearings 31 and 30 in the vicinity of the first and second bearings 31 and 30, respectively. , 30 are not shifted.

The first frame 29 is provided with a cutout portion 40 in which a part of a wall (upper wall in FIG. 4) 29a surrounding the periphery of the circuit board 7 is cut out. At both ends of the cutout portion 40, there are provided contact portions 41 and 42 which contact the float arm 2 and regulate the rotation range. The notch 40 is the first
The guide portion 43 is configured in a state where the frame 29 and the second frame 28 are assembled. This guide part 43
Thereby, the movement of the float arm 2 in the rotation axis direction can be suppressed. As described above, the pin 35b and the hole 36b are provided near the contact portions 41 and 42. For this reason, even if the float moves due to fluctuations in the liquid level, the float arm 2 moves in the direction of the rotation axis and hits the guide portion 43, and even if force is applied to the first and second frames 29 and 28,
Pins 3 forming welding fixing portions near contact portions 41 and 42
By providing 5b and 36b, the rigidity of the first and second frames 29 and 28 is increased, and a strong frame structure in which the engagement between the locking claw 32 and the locking portion 34 is not released can be obtained. .

The circuit board 7 is made of ceramic, and has a conductor 44 and a resistor (not shown) arranged on the surface thereof in a comb-like shape. The circuit board 7 is fixed to the first frame 29. The first frame 29 is provided with a concave portion 45 for accommodating the circuit board 7, and is provided with elastic pieces 48, 49 having locking claws 46, 47 respectively locking on opposite sides of the rectangular circuit board 7. ing. The elastic pieces 48 and 49 provided with the locking claws 46 and 47 cause the circuit board 7 to
Pressed to the side and fixed.

The terminal 20 is made of metal and is formed by bending a plate-like member. The terminal 20 includes an elastic contact piece 20a that comes into contact with a land (not shown) connected to the conductor 44 of the circuit board 7. The tip of the contact piece 20a has a structure that branches into two and contacts the circuit board 7 at two points.

Further, a groove 20c for inserting and holding the end of the circuit board 7 is provided on the side surface, and the contact piece 20a is provided so as to be securely connected to the circuit board 7.

Reference numeral 20d denotes a stopper for preventing the terminal 20 connected to the circuit board 7 from coming off, which is locked by a locking portion 52 provided on the first frame 29. 20e is the conductive wire 2 of the lead wire 21.
A first fixing portion for fixing the portion 1a and electrically connecting to the terminal 20 is provided. A second fixing portion 20f for fixing the covering portion 21b of the lead wire 17 is provided.
20f is also deformed and 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 first frame 29 in advance, and connecting the terminal 20 to the terminal housing 53 provided on the first frame 29 in the direction of the arrow in FIG. Insert

With the above configuration, the first and second frames 2
First and second bearing portions 31 and 30 for receiving the shaft portion 24 are provided in each of the first and second bearing portions 31 and 3.
0, the arm holder 4 is held, and the first and second bearings 3 are held.
By arranging the float arm 2 and the sliding plate 61 between the first and the second 30, it is possible to provide the liquid level detecting device 1 which is thinner than the conventional one. In addition, the sliding contact 60 and the sliding plate 61
Are formed integrally, the axial thickness of the shaft portion 24 of the sliding contact 60 and the sliding plate 61 can be reduced,
A thinner liquid level detection device 1 can be provided. Further, the shaft portion 24 is provided separately, and the first and second bearing portions 3 are provided.
By holding both sides at 1, 30, the arm holder 4
The effect that the center of rotation of the rotating shaft is hardly blurred can be obtained.

In this embodiment, since the axial direction of the bent end portion 12 is set so as to be substantially orthogonal to the axial direction of the shaft portion 24, the first and second bearing portions 31 are provided. ,
30 can be reduced, and a thinner liquid level detecting device can be provided. Note that any angle may be set as long as the axial direction of the shaft portion 12 intersects the axial direction of the shaft portion 24.

The sliding contact 60 and the sliding plate 61 of the present invention are used.
Is not limited only to the arm holder 4 support structure of the present embodiment, but may be applied to a liquid level detection device to which the arm holder 4 support structure shown in the conventional example is applied.

[0043]

As described above, according to the present invention, an initial object can be achieved, the number of parts can be reduced, and a liquid level detecting device capable of performing reliable energization is provided. be able to.

[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 a second frame and an arm holder removed.

FIG. 5 is a side view of the embodiment.

FIG. 6 is a top view of the float arm and the arm holder of the embodiment.

FIG. 7 is a back view of the float arm and the arm holder of the embodiment.

FIG. 8 is a sectional view taken along line CC in FIG. 6;

FIG. 9 is a side view of the arm holder of the embodiment.

FIG. 10 is a rear view of the arm holder and the sliding holding member of the embodiment.

FIG. 11 is a top view of a conventional example.

FIG. 12 is a sectional view taken along line DD in FIG. 11;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 liquid level detecting device 2 float arm 3 main body frame 4 arm holder 5 contact holding member 6, 60 sliding contact 7 circuit board 24 shaft portion 28 second frame 29 first frame 30 second bearing portion 31 first bearing portion 61 sliding member (sliding plate) 62 arm piece 63 notch 64 plate-shaped part

Claims (4)

[Claims] 1. A float arm having a float floating on a liquid surface, an arm holder having a shaft that holds the float arm and is a pivot of the float arm, and a shaft of the arm holder. A supporting frame,
A circuit board fixed to the frame, and a sliding member integrally having sliding contacts sliding on the circuit board and fixed to the arm holder, wherein the sliding member is provided on the circuit board side. A liquid level detecting device, comprising: an arm piece extending endlessly toward the arm; and the sliding contact is provided on the arm piece. 2. A float arm having a float floating on a liquid surface, an arm holder holding the float arm and having a shaft serving as a pivot of the float arm, and a shaft of the arm holder. A first frame having a first bearing portion that supports the first frame; a second frame having a second bearing portion that supports the shaft portion of the arm holder;
A circuit board fixed to the frame; and a sliding member integrally having sliding contacts sliding on the circuit board and fixed to the arm holder, wherein the sliding member faces the circuit board side. A liquid surface detecting device, comprising: an arm piece extending endlessly; and the sliding contact provided on the arm piece. 3. The liquid level detecting device according to claim 1, wherein a plurality of said sliding contacts are provided. 4. The liquid level detecting device according to claim 3, wherein the sliding contact is provided with a notch and divided into a plurality of parts.