JP2012052911A - Liquid level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detector that is to be incorporated into a fuel pump module to be arranged within a fuel tank, is enhanced in fitting ease and in the ease of being inserted into the fuel tank by virtue of its smaller size, and is reduced in price by cutting back the number of components used and that of steps of the working process.SOLUTION: A liquid level detector that detects variations in liquid level in a fuel tank with a float floating on the liquid surface in the tank comprises: a fitting member disposed on a fuel pump module; a float arm oscillatablly fitted to a frame fitted to the fitting member and linked to the float; a movable contact disposed on and co-moving with the float arm; and an electroconductive pattern that causes the movable contact to slide, further provided with a circuit board fitted to the frame and a lead wire that sends the electricity, whose quantity varies with the sliding of the electroconductive pattern caused by the movable contact, of the circuit board to outside. A through hole penetrating both the frame and the circuit board is provided and the lead wire passing this through hole is connected to the electroconductive pattern and the movable contact.

Description

  The present invention relates to a liquid level detection device that is mounted on a fuel pump module that is held in an opening of a fuel tank that stores fuel and that sends the fuel out of the fuel tank, and detects a liquid level in the fuel tank. It is about.

  A conventional liquid level detecting device includes a float that floats on a fuel level in a fuel tank, a float arm that is assembled with the float, an arm holder that holds the float arm and includes a bearing portion that is a pivotal fulcrum of the float arm, and an arm holder The upper and lower frames that pivotally support the bearings, the circuit board that is fixed to the frame, and the contacts that slide on the circuit board. The float moves up and down due to liquid level fluctuations in the fuel tank. Accordingly, the contact point slides on the circuit board via the float arm, and the liquid level in the fuel tank is detected by outputting a signal corresponding to the liquid level. (For example, see Patent Document 1)

Japanese Patent No. 3981858

  The liquid level detection device is assembled in a fuel pump module and arranged in a fuel tank, and it is required to improve the ease of assembly, improve the ease of insertion into the fuel tank by downsizing, and reduce the cost. .

  However, in the above-described conventional example, since the upper frame is provided, the height direction is thick, there is a limit to downsizing, the number of parts increases, and the upper frame and the lower frame are fixed. There are problems such as time-consuming manufacturing due to welding work.

  The present invention has been made to solve the above-described problems, and provides a low-priced liquid level detection device by improving the insertability into a fuel tank by downsizing and reducing the number of parts and work processes. Is what you do.

  A liquid level detection device according to the present invention is provided in a fuel pump module for sending fuel out of a fuel tank, and detects a liquid level fluctuation in the fuel tank by a float floating on the liquid level in the fuel tank. In the detection device, an attachment member provided on the fuel pump module, a frame attached to the attachment member, a float arm that is swingably attached to the frame and connected to the float, and the liquid provided to the float arm A movable contact that cooperates with the float arm in accordance with surface fluctuation, a conductive pattern that slides the movable contact, a circuit board attached to the frame, and the movable contact slides on the conductive pattern A lead wire for sending the amount of electricity of the circuit board, which changes depending on In the overlapped part formed at the time of mounting the circuit board, a through hole is provided that penetrates both and penetrates the lead wire, and in the through hole portion, the lead wire is connected to the conductive pattern and the movable contact, Each is connected.

  According to the liquid level detection device of the present invention, the upper frame as in the conventional example is not required, and the lead wire is directly connected to the circuit board by inserting the lead wire from the through hole of the circuit board provided in the circuit board. , The terminal for connecting to the circuit board, and the terminal receiving part that holds the terminal can be abolished, the insertion into the fuel tank is improved by downsizing, the number of parts is reduced, and the work A liquid level detection device capable of reducing the number of processes can be provided.

It is an external appearance perspective view of the liquid level detection apparatus in Embodiment 1 of this invention. It is a disassembled perspective view of the liquid level detection apparatus in Embodiment 1 of this invention. It is the front view which looked at FIG. 2 in the arrow A direction. FIG. 4 is a rear view in FIG. 3. It is sectional drawing which looked at the VV line in FIG. 3 in the arrow direction. It is explanatory drawing at the time of attaching a liquid level detection apparatus to an attachment member, (a) is a state figure before attachment, (b) is a state figure after attachment.

Embodiments of the present invention will be described below with reference to the drawings.
In addition, the same code | symbol shows the same or an equivalent part between each figure.

Embodiment 1 FIG.
As shown in the drawing, the liquid level detection device in the first embodiment sandwiches the float arm 7 between the frame front opening 1c and the mounting member 10 disposed in the fuel pump module disposed in the fuel tank. The frame 1 is attached to the mounting member 10 with the back side of the frame back wall 1d exposed, and lead wires are inserted from the frame back wall 1d through the frame through hole and the circuit board through hole and directly into the circuit board 2. It is intended to be connected.

  In FIG. 1, the liquid level detection device is configured to be attached to an attachment member 10 disposed in a fuel tank (not shown), and the attachment member 10 is, for example, a sub tank that forms a fuel pump module (not shown). The attachment member 10 is a flat plate, but may be a curved surface.

The liquid level detection apparatus according to Embodiment 1 is configured as shown in FIGS.
That is, the liquid level detection device holds a float 8 floating on a fuel level in a fuel tank (not shown), a float arm 7 coupled (connected) to the float 8, and the float arm 7 and the float 8. A push nut 9 (FIG. 1), an arm holder 3 having a bearing portion 3a which is a pivot point of the float arm 7, and holding the float arm 7 in a swingable manner, and a bearing portion 3a of the arm holder 3 will be described later. A frame 1 that is supported (supported) by a supporting portion 1f for arm holder bearings, and a circuit board that is fixed to the frame 1 as will be described later and is provided with conductive patterns 2b and circuit board through holes 2a and 2b. 2, a movable contact 4 slidably contacting on the circuit board 2, a conductive spring 5 for electrically connecting the movable contact 4 and the circuit board 2, and one end of the conductive spring A change in the amount of electricity by the movable contact 4 that is connected to one end of the conductive pattern 2b as described later and slides on the circuit board 2 in accordance with the liquid level change, for example, a change in electric current (electric signal) is sent to the outside. For example, the lead wires 6a and 6b are used.

The frame 1 has a frame front opening 1c and a frame rear wall 1d, and a circuit board fitting recess 1e for incorporating (fitting) the circuit board 2 is formed in the frame rear wall 1d. Yes.
The frame back wall 1d adjacent to the circuit board fitting recess 1e is provided with an arm holder bearing support 1f that supports (supports) the bearing 3a. By press-fitting the bearing portion 3a into the support portion 1f, the float arm 7 is supported rotatably (swingable) around the arm holder bearing portion support portion 1f while being fixed in the axial direction.

Further, circuit board pressing portions 1g and 11g project from the frame front surface opening 1c to which the circuit board 2 is assembled. When the circuit board 2 is assembled to the frame 1, the circuit board pressing portion 1g and 11g project. Secure it so that it does not come off.
In addition, as will be described later, the frame 1 includes a lead wire holding portion 1h, liquid level detection device holding rails 1j and 11j, a conductive spring mounting shaft 1s, lead wire frame through holes 1a and 1b, and the like.

  In addition, the movable contact 4 assembled | attached to the arm holder 3 is assembled | attached to the back surface of the arm holder 3 which is not shown in figure, and is fixed to the arm holder 3 by heat welding, for example.

The conductive pattern 2b, the movable contact 4, and the conductive spring 5 are connected as follows.
The arm holder bearing support portion 1 f provided on the frame 1 is connected to the bearing portion 3 a of the arm holder 3.
The arm holder 3 is fixed to be freely rotatable about the arm holder bearing support 1f, and then a conductive spring 5 for electrical conduction is connected in the vicinity of the arm holder bearing support 1f. At this time, one end 5a of the conductive spring 5 is connected to the movable contact 4 that slides on the circuit board 2, and the other end 5b is connected to the circuit board 2 as described later. 2b is inserted and temporarily fixed.

Next, connection and fixing of the lead wires 6a and 6b will be described.
The through-holes 1a and 1b of the frame and the through-holes 2a and 2b of the circuit board are formed when the circuit board 2 is overlapped and attached to the circuit board fitting recess 1e of the frame 1 as shown in FIG. They are respectively provided so that both penetrate through the same axis.

The lead wire 6a is inserted from the frame through hole 1a into the circuit board through hole 2a, and the lead wire 6b is inserted from the frame through hole 1b into the circuit board through hole 2b. In FIG. 2, each of them is connected and fixed by solder.
That is, the lead wires 6a and 6b are inserted into the frame through holes 1a and 1b and the circuit board through holes 2a and 2b, and then connected to lead wires and conductive springs provided in a part of the circuit board 2. Electrode patterns Ta and Tb (configured by part of the electrode pattern instead of the terminal) are connected by solder. At this time, the other end 5b of the conductive spring 5 is inserted from the circuit board through hole side and soldered to the frame through hole 1b and the circuit board through hole 2b through which the lead wire 6b is inserted, simultaneously with the lead wire 6b.
That is, the lead wire 6a is inserted from the frame through hole 1a to the circuit board through hole 2a, and is connected and fixed by the connecting electrode pattern Ta by solder. The lead wire 6b is inserted into the circuit board through hole 2b from the frame through hole 1b. At the same time, the other end 5b of the conductive spring is inserted into the frame through hole 1b from the circuit board through hole 2b and then connected to the conductive pattern Tb for connection. The connection is fixed by soldering.

  By configuring as described above, the terminals for holding the lead wires 6a and 6b and connecting to the circuit board 2 can be eliminated, and the terminal receiving part for holding the terminals can be eliminated at the same time. Reduction of work processes and downsizing can be realized.

  Further, the soldering process of soldering the conductive spring 5 and the circuit board 2 and the soldering of the lead wires 6a and 6b and the circuit board 2 is not necessary, and the soldering process can be integrated at a time.

After the lead wires 6a and 6b are inserted from the back side of the frame rear wall portion 1d, the lead wires 6a and 6b are hooked and held on the lead wire holding portion 1h disposed on the frame 1, so that the lead wires 6a and 6b are liquid surfaces in the fuel tank. It is possible to prevent disconnection and film tearing caused by contact with other parts due to vibration caused by

  The configuration of the liquid level detection device according to the present invention is such that when the parts such as the circuit board 2 and the arm holder 3 are assembled from the frame front opening 1c and are attached to the attachment member 10 provided in the fuel pump module, the frame The front opening 1c comes into contact with the attachment member 10, and the back side of the frame rear wall 1d is exposed.

  The lead wire 6a, 6b connection structure of the liquid level detection device according to the present invention is possible because the liquid level detection device is attached to the mounting member 10 with the back side of the frame rear wall portion 1d exposed as described above. It has a configuration.

  One end of the float arm 7 that holds the float 8 is inserted into a through hole (not shown) provided in the float 8 that floats on the fuel level in the fuel tank, and is prevented from being detached by a push nut 9. The other end of the other end is press-fitted and fixed to an arm holder 3 that is rotatably attached to an arm holder bearing support 1f disposed on the frame 1, and the liquid level in the fuel tank is changed. The accompanying vertical movement of the float 8 is transmitted to the arm holder 3 via the float arm 7 and to the movable contact 4 assembled to the arm holder 3.

  In the liquid level detection apparatus configured as described above, the float 8 detects the liquid level height, is transmitted to the movable contact 4 via the float arm 7, and is brought into sliding contact with the circuit board 2, thereby The liquid level in the tank is converted into an electric signal, which is output to the outside through the conductive spring 5 and the lead wires 6a and 6b.

  Next, the operation of mounting the liquid level detection device configured as described above on the mounting member 10 provided in the fuel pump module (not shown) will be described with reference to FIG.

The liquid level detection device holding rails 1j and 11j respectively disposed on the upper and lower sides of the frame 1 are liquid level detection device main body mounting guides 10a disposed on the upper and lower positions of the mounting member 10, respectively.
Is inserted until it abuts against the abutting portion 10b disposed in the guide.

  When the liquid level detection device holding rails 1j and 11j are inserted along the liquid level detection device main body mounting guide guide 10a, the claw portions 1k and 11k provided on the frame 1 are provided on the guide 10a. It contacts the locking portion 10c and is inserted while being elastically deformed inside.

At the same time that the liquid level detection device holding rails 1j and 11j are brought into contact with the contact portion 10b, the claw portions 1k and 11k that are inserted while being elastically deformed pass through the inside of the locking portion 10c to return to the original shape. At the same time, the claw portions 1k and 11k and the locking portion 10c come into contact with each other and the frame 1 is prevented from coming off.

  As described above, according to the embodiment of the present invention, it is possible to reduce the manufacturing cost by improving the insertability to the fuel tank by reducing the size, reducing the number of parts and the work process, and providing a low-cost liquid level detection device. It becomes possible.

DESCRIPTION OF SYMBOLS 1 Frame 1a, 1b Frame through-hole for lead wires 1c Frame front opening 1d Frame back wall 1e Circuit board fitting recess 1f Arm holder bearing support 1g, 11g Circuit board presser 1h Lead wire holding part 1j, 11j Rail for holding liquid level detection device 1k, 11k Claw part 1s Conductive spring mounting shaft 2 Circuit board 2b Conductive pattern 2a, 2b Circuit board through hole 3 Arm holder 3a Arm holder bearing part 4 Movable contact 5 Conductive spring 5a, 5b Conductive spring terminal 6 6a, 6b Lead wire 7 Float arm 8 Float 9 Push nut 10 Mounting member 10
10a Liquid level detection device main body mounting guide 10b Contact portion 10c Locking portion.

Claims (3)

In a liquid level detection device that is equipped in a fuel pump module for sending fuel out of a fuel tank and detects a liquid level fluctuation in the fuel tank by a float that floats on the liquid level in the fuel tank,
A mounting member provided in the fuel pump module, a frame attached to the mounting member, a float arm that is swingably attached to the frame and connected to the float, and provided in the float arm according to the liquid level fluctuation A movable contact that cooperates with the float arm, a conductive pattern that slides the movable contact, a circuit board attached to the frame, and the movable contact that changes as the movable contact slides on the conductive pattern Provided with a lead wire that sends out the amount of electricity of the circuit board to the outside, a through hole that penetrates both the lead wires through the overlapping portion formed when the circuit board is attached to the frame is provided. In the through hole portion, the conductive pattern and the movable contact are respectively connected to the lead wire; That the liquid level detection device.   2. The liquid level detection device according to claim 1, wherein an attachment surface side of the frame to which the float arm and the circuit board are attached is directly attached to the attachment member.   The liquid level detection device according to claim 2, wherein the frame is provided with a lead wire holding portion for holding the lead wire.

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