JP2018136203A - Liquid level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detector with which it is possible to arrange a circuit board for a holder with high accuracy.SOLUTION: There is provided a liquid level detector F comprising a circuit board 4, a holder 2 that holds the circuit board 4 and revolves in association with the motion of a float FL that moves following a liquid level, a terminal 5 having a contact 5A that is in contact with an electrode part 4A of the circuit board 4, and a frame 1 having a portion of the terminal 5 within. The holder 2 includes a board storage part 2A0 for arranging the circuit board 4 and a pair of hooks 2A1 that come in contact with two orthogonal sides 4B of the circuit board 4, the board storage part 2A0 being provided with two opposing parts 2A2, with its two sides 4C facing the orthogonal sides 4B of the circuit board 4 facing each other, at least one of the two opposing parts 2A2 being provided with a movement blocking part 2A4 for blocking movement in a direction perpendicular to the board surface direction of the circuit board 4.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a liquid level detection device that detects the level of fuel in a fuel tank of a vehicle.

  A conventional liquid level detection device rotates a circuit board with respect to a fixed contact fixed to a frame. The circuit board is held by a holder, and the liquid level is detected by rotating the holder around a rotation axis. It was to detect a change in resistance value associated with the fluctuation (see Patent Document 1).

Japanese Patent Laying-Open No. 2015-221716

  However, in the structure in which the circuit board is fixed to the holder, a structure in which three sides of the rectangular circuit board are fastened with hooks and one corner of the circuit board is pressed against a corner portion of the arrangement portion that stores the circuit board of the holder. However, when the hooks are present on the two opposite sides and the side located between the two sides, the hooks located on the two opposite sides press the circuit board against each other. As a result, there is a problem that misalignment occurs between the fixed contact and the circuit board, and it is difficult to obtain a desired detection accuracy.

  The present invention pays attention to the above-described problems, and provides a liquid level detection device capable of accurately arranging a circuit board with respect to a holder.

  The liquid level detection device F of the present invention is in contact with a circuit board, a holder that holds the circuit board and rotates with movement of a float that follows the liquid level, and an electrode portion of the circuit board. In a liquid level detection device comprising a terminal having a contact and a frame containing a part of the terminal, the holder includes a substrate storage portion for disposing the circuit board, and on two orthogonal sides of the circuit board. A pair of hooks in contact with each other, and the substrate storage portion includes two opposing portions opposed to two orthogonal sides of the circuit board, and at least one of the two opposing portions of the circuit board. A movement blocking unit for blocking vertical movement with respect to the plate surface direction is provided.

  The liquid level detection device of the present invention can provide a liquid level detection device capable of accurately arranging the circuit board with respect to the holder.

The perspective view of the liquid level detection apparatus of 1st embodiment of this invention. The front view of the liquid level detection apparatus of the embodiment. The front view of the flame | frame of the embodiment. The rear view of the flame | frame of the embodiment. Sectional drawing of the principal part before crimping the terminal of the embodiment. The perspective view of the holder of the embodiment. The perspective view which looked at the circuit board and holder of the embodiment from the back. The perspective view seen from the back of the holder which assembled | attached the circuit board of the embodiment. The perspective view which looked at the circuit board and holder of 2nd embodiment of the invention from the back. The perspective view seen from the back of the holder which assembled | attached the circuit board of the embodiment.

  Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the liquid level detection device F of the present invention includes a frame 1, a holder 2, a float arm 3, a circuit board 4, a terminal 5, a wiring cord (wiring) 6, And is used as a liquid level detection device for detecting the level of various liquids in a tank of a vehicle such as an automobile or motorcycle. Further, the liquid level detection device F is fixed to a fuel pump (not shown) made of synthetic resin or the like, an attachment stay, or the like.

  The frame 1 is made of a synthetic resin, for example, polyacetal, and integrally includes a base portion 11, a stopper 12, a hook portion 13, and a bearing portion 14 as shown in FIGS. Further, a part of the terminal 5 is built in the frame 1 by insert molding.

  The base part 11 has three rectangular openings 11A, 11B, and 11C. Each opening 11 </ b> A, 11 </ b> B, 11 </ b> C penetrates the holder 2 in the rotation axis direction. In the first and second openings 11A and 11B, the crimped portion 5B of the terminal 5 is exposed, and in the third opening 11C, the contact 5A of the terminal 5 is exposed.

  First and second projecting portions 11E and 11F project from the wall surface 11D on the terminal 5 side of the first and second openings 11A and 11B, respectively. The contact surface 11H of the first protrusion 11E is a surface with which an end of a wiring cord 6 described later contacts. As shown in FIG. 5, the first protrusion 11 </ b> E is provided on the placement surface 5 </ b> E of the wiring cord 6 and includes a guide surface 11 </ b> G at the end. The 2nd protrusion part 11F is provided in the back surface 5F of a mounting surface. The first protrusion 11E and the second protrusion 11F are opposed to each other with the terminal 5 interposed therebetween. The first and second projecting portions 11 </ b> E and 11 </ b> F serve as reinforcing portions that prevent the terminal 5 from being deformed.

  The stopper 12 is composed of a first stopper 12A and a second stopper 12B. As shown in FIGS. 3 and 4, the rotation angle of the holder 2, that is, a float, is formed between the first and second stoppers 12A and 12B. The operating range of the arm 3 is defined.

  Three hook portions 13 are provided and are engaged with the fuel pump, the mounting stay, or the like.

  The bearing portion 14 is provided on the outer peripheral portion of the frame 1, and includes a through hole 14 </ b> A through which the shaft portion 3 </ b> A of the float arm 3 is inserted and rotatably supported, and the holder 2 is rotatably supported. .

  The holder 2 holds the circuit board 4 and rotates the circuit board 4 in accordance with the movement of the float FL that operates following the liquid level. The holder 2 is made of synthetic resin, for example, polyacetal resin. As shown in FIGS. 6 and 7, the plate-shaped upper piece 2A, the lower piece 2B facing the upper piece 2A, the upper piece 2A, and the lower piece 2B. And 2C of connection parts which connect.

  The upper piece 2A includes a substrate housing portion 2A0 for arranging the circuit board 4, first and second locking portions 2D1 and 2D2 for holding the float arm 3, and the float arm 3 for the first and second locking portions 2D1. 2D2, a retaining portion 2D3 for preventing the slipping from 2D2, a contact portion 2E that makes contact with the stopper 12 of the frame 1, and an insertion portion 2F comprising a through hole through which the shaft portion 3A of the float arm 3 is inserted. I have.

  The substrate housing part 2A0 is arranged so that the electrode part 4A formed on the circuit board 4 is exposed on the surface. The board housing portion 2A0 includes two hooks 2A1 that come into contact with two orthogonal sides 4B of the circuit board 4. In addition, the substrate storage portion 2A0 includes two opposing portions 2A2 that face two opposite sides 4B of the circuit board 4 with which the two hooks 2A1 abut (opposite sides of the two sides 4B) and face two sides 4C. . In addition, the opposing portion 2A2 is provided with a plurality of positioning portions 2A3 that come into contact with the circuit board 4. Further, the board housing part 2A0 is provided with a movement blocking part 2A4 for blocking the movement in the vertical direction with respect to the plate surface direction of the circuit board 4.

  Each hook 2 </ b> A <b> 1 stops the movement in the vertical direction with respect to the plate surface direction of the circuit board 4 by locking the outer peripheral portion of the circuit board 4. Each hook 2A1 includes an elastic portion 2A11, and the elastic portion 2A11 presses the circuit board 4 against the opposing portion 2A2 side of the substrate storage portion 2A0 by the elastic force.

  Two positioning portions 2A3 are provided in each facing portion 2A2. The facing portion 2A2 has a semi-cylindrical shape and protrudes from each facing portion 2A2 in a direction parallel to the plate surface direction of the circuit board 4 stored in the substrate storage portion 2A0. The cross-sectional shape (the cross-sectional shape in the direction parallel to the plate surface direction of the circuit board 4) is an arc shape, and the contact area with the side 4C of the circuit board 4 can be suppressed. By providing this positioning part 2A3, there are many parts in contact between the side 4C of the circuit board 4 and the facing part 2A2 of the board storage part 2A0, and it is difficult to determine the position of the circuit board 4 with respect to the holder 2. By providing the portion 2A3, it is possible to easily position the circuit board 4 with respect to the holder 2 by minimizing the contact portion with the circuit board 4.

  In the present embodiment, two movement blocking units 2A4 are provided. One is between the two opposing portions 2A2, and the other is provided only in the opposing portion 2A2. In the present embodiment, the movement preventing portion 2A4 has a flat plate shape and projects in a direction parallel to the plate surface direction of the circuit board 4 accommodated in the substrate accommodating portion 2A0 from the facing portion 2A2. In the present embodiment, the movement prevention unit 2A4 is provided at a position corresponding to the two corners of the circuit board 4. The movement blocking unit 2A4 and the circuit board 4 may be in contact with each other, or may have a slight gap in consideration of a tolerance when the circuit board 4 is arranged in the board storage unit 2A0. By providing the movement preventing portion 2A4, it is possible to prevent movement in the vertical direction with respect to the plate surface direction of the circuit board 4. In the present embodiment, two movement blocking units 2A4 are provided, but the number of movement blocking units 2A4 may be one. Further, the position where the movement preventing portion 2A4 is provided may be the side 4C of the circuit board 4 instead of the corner of the circuit board 4.

  With the above configuration, the outer peripheral portion of the circuit board 4 is fixed by the plurality of hooks 2A1, and the movement in the vertical direction with respect to the plate surface direction of the circuit board 4 is blocked by the plurality of hooks 2A1 and the movement blocking section 2A4. Can do.

  The lower piece 2 </ b> B includes an insertion portion 2 </ b> B <b> 1 including a through hole through which the shaft portion 3 </ b> A of the float arm 3 is inserted.

  The connecting portion 2C connects the upper piece 2A and the lower piece 2B. The insertion part 2F of the upper piece 2A and the insertion part 2B1 of the lower piece 2B are connected.

  The bearing portion 14 of the frame 1 is sandwiched between the upper piece 2A and the lower piece 2B. The bearing portion 14 is sandwiched between the insertion portion 2F of the upper piece 2A and the insertion portion 2B1 of the lower piece 2B.

  The float arm 3 is made of a hard steel wire, and is bent into a predetermined shape so as to be attached to the holder 2 or matched to the fuel tank shape. A float FL is fixed to one end of the float arm 3. The float FL is made of NBR / phenol foam, floats on the liquid level of the fuel, etc., and operates following the liquid level. Further, a shaft portion 3A is provided at the other end. The shaft portion 3A passes through the through-hole 14A of the bearing portion 14 of the frame 1 and the two insertion portions 2F and 2B1 of the holder 2, so that the holder 2 is rotated about the shaft portion 3A of the float arm 3 as a rotation center. The frame 1 is supported so as to be rotatable.

  The circuit board 4 has a rectangular shape and is made of an insulating material such as alumina. On the surface thereof, an electrode portion 4A is provided, and a conductive material and a resistance material constituting the electrode portion 4A are formed on the circuit board 4 by printing and baking. The circuit board 4 is attached to the holder 2 and interlocks with a float FL that operates following the liquid level.

  The terminal 5 is made of, for example, a white material, and two terminals 5 are provided. Each terminal 5 includes an elastic piece 5D having a contact 5A that contacts the electrode part 4A of the circuit board 4, a crimping part 5B that holds the wiring cord 6, a covering crimping part 5B1, an elastic piece 5D, and a crimping part. The relay unit 5C that connects the 5B is provided integrally.

  The contact 5A is made of, for example, an alloy of palladium and nickel that contacts the electrode portion 4A of the circuit board 4 and slides on the electrode portion 4A. The elastic piece 5 </ b> D is formed such that the contact 5 </ b> A protrudes from the surface on the holder 2 side of the frame 1, and the contact 5 </ b> A is in contact with the circuit board 4.

  As shown in FIG. 3 to FIG. 5, the wiring cord 6 is composed of two wires, a ground wire and an output signal wire, and includes a conductor portion 6 </ b> A and a covering portion 6 </ b> B. Connected.

  As a procedure for assembling the wiring cord 6 to the terminal 5, first, the wiring cord 6 is assembled so as to pass through the slit 11 </ b> I of the frame 1. At this time, the end portion of the wiring cord 6 is provided so as to abut against the contact surface 11H of the first protruding portion 11E provided on the mounting surface 5E side of the terminal 5. The slit 11I has a structure in which the wiring cord 6 is locked and is not easily removed. Further, even if the insertion amount of the wiring cord 6 into the frame 1 is too large and the end portion of the wiring cord 6 is lifted from the proper position, the wiring shown in FIG. The cord 6 can be led to an appropriate position. In this state, that is, at the position where the exposed wire portion 6A of the wiring cord 6 and the crimping portion 5B of the terminal 5 overlap, the crimping portion 5B can be deformed and crimped, and the terminal 5 and the wiring cord 6 are connected. The wiring cord 6 can be held on the mounting surface 5E of the terminal 5 while being in an electrically conductive state. In addition, the covering crimping portion 5B1 can be crimped at an appropriate position while deforming the covering portion 6B of the wiring cord 6, and a desired retaining strength of the wiring cord 6 can be obtained. It becomes.

  As described above, the present invention contacts the circuit board 4, the holder 2 that holds the circuit board 4 and rotates with the movement of the float FL that follows the liquid surface, and the electrode portion 4 </ b> A of the circuit board 4. In a liquid level detection device F including a terminal 5 having a contact 5A and a frame 1 in which a part of the terminal 5 is built, the holder 2 includes a substrate storage portion 2A0 in which the circuit substrate 4 is arranged and the circuit substrate 4. A pair of hooks 2A1 that come into contact with two orthogonal sides 4B of the circuit board 4, and the substrate storage portion 2A0 includes two opposing portions 2A2 that are opposed to two orthogonal sides 4B of the circuit board 4, and two opposing portions 2A2. By providing the movement blocking portion 2A4 that blocks the movement in the vertical direction with respect to the plate surface direction of the circuit board 4 on at least one of the facing portions 2A2, the circuit board 4 is accurately arranged with respect to the holder 2. It is possible to provide a possible liquid level detecting device F.

  Next, a second embodiment of the present invention will be described with reference to FIGS.

  In the present embodiment, the movement preventing portion 2A4 is formed integrally with one of the positioning portions 2A3 provided in a plurality of facing portions 2A2 of the holder 2 facing the two sides 4C of the circuit board 4. In the present embodiment, the movement preventing part 2A4 is provided in one positioning part 2A3, but the movement preventing part 2A4 may be provided in all positioning parts 2A3.

  With the above configuration, it is possible to provide the liquid level detection device F that can accurately arrange the circuit board 4 with respect to the holder 2. Further, by forming the positioning portion 2A3 and the movement blocking portion 2A4 integrally, the holder 2 can be formed in a smaller size compared to the case where the positioning portion 2A3 and the movement blocking portion 2A4 are formed separately.

  The above description exemplifies the present invention, and it goes without saying that various changes and modifications can be made without departing from the scope of the invention.

  The present invention is applicable to a liquid level detection device that detects the liquid level of various liquids in a tank.

F Liquid level detection device FL Float 1 Frame 2 Holder 2A Upper piece 2A0 Substrate storage part 2A1 Hook 2A2 Opposing part 2A3 Positioning part 2A4 Movement prevention part 2B Lower piece 2B1 Insertion part 2C Connection part 3 Float arm 3A Shaft part 4 Circuit board 4A Electrode Part 4B Side 4C Side 5 Terminal 5A Contact 5B Clamping part 5B1 Covering Clamping part 5C Relay part 5D Elastic piece 5E Mounting surface 5F Back surface 6 Wiring 6A Conducting part 6B Covering part 11 Base part 11A First opening part 11B Second opening Part 11C 3rd opening part 11D Wall surface 11E 1st protrusion part 11F 2nd protrusion part 11G Guide surface 11H Contact surface 11I Slit 12 Stopper 12A 1st stopper 12B 2nd stopper 13 Hook part 14 Bearing part 14A Protrusion part

Claims (2)

A circuit board; a holder that holds the circuit board and rotates with movement of a float that follows the liquid surface; a terminal that has a contact point that contacts the electrode part of the circuit board; In the liquid level detecting device, the holder includes a substrate storage unit for disposing the circuit board, and a pair of hooks that come into contact with two orthogonal sides of the circuit board. The storage portion includes two opposing portions facing two opposite sides of the circuit board opposite to each other, and at least one of the two opposing portions moves in a direction perpendicular to the plate surface direction of the circuit board. A liquid level detecting device provided with a movement blocking unit for blocking water. 2. A plurality of positioning portions that abut against the circuit board are provided at opposing portions facing the two sides, and at least one of the plurality of positioning portions is formed integrally with the movement preventing portion. The liquid level detection apparatus described.

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