JP2016166742A - Liquid level detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detection device that make it possible to suppress deformation of a holder due to deformation of a float arm, and suppress reduction in reliability of an electric connection between a circuit substrate and a contact.SOLUTION: A liquid level detection device F comprises: a float arm 1 that has a float operative following a liquid level provided at one end, and a shank part provided in the other end; a holder 2 that includes a lock part holding the float arm 1, and rotates accompanied by a motion of the float arm 1; a frame 3 that rotatably supports the holder 2; a circuit substrate that is fixed in the holder 2 or frame 3; and terminals each provided with a contact that makes contact with an electrode part of the circuit substrate, and fixed in the frame 3 or holder 2. In the liquid level detection device, provided are: a guide rail part 36 that is provided in the frame 3 so as to run along a rotation trajectory of the holder 2; and a slide part 2E that is provided in the holder 2 so that holder 2 is movable along the guide rail part 36.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid level detection device for detecting the level of fuel in a fuel tank of an automobile.

  A conventional liquid level detection device holds a float arm that moves as the liquid level fluctuates and a circuit board, contacts that make sliding contact with a plurality of electrodes provided on the circuit board, and holds the contacts. And a frame that rotatably supports the float arm, and outputs an electrical signal in which a resistance value is changed by the contact of the contact with at least one of the plurality of electrodes as the float arm fluctuates. (For example, see Patent Document 1).

JP 2010-38550 A

    In recent years, as means for reducing costs, it has been proposed to reduce the diameter of the float arm to reduce raw material costs. However, by reducing the diameter of the float arm, the strength of the float arm is reduced, and the float arm is easily deformed. Due to the deformation of the float arm, the holder holding the float arm is deformed, affecting the contact state between the circuit board and the contact, and the reliability of the electrical connection between the circuit board and the contact. There was a problem that there was concern about the decline.

  Therefore, the present invention pays attention to the above-mentioned problems, and suppresses the deformation of the holder due to the deformation of the float arm, and the liquid level detection capable of suppressing the decrease in the reliability of the electrical connection between the circuit board and the contact point. A device is provided.

  The present invention includes a float arm that has a float that operates following the liquid level at one end and a shaft portion at the other end, a locking portion that holds the float arm, and a movement of the float arm. A holder that rotates, a frame that rotatably supports the holder by a bearing portion that rotatably supports the shaft portion, a circuit board that is fixed to the holder or the frame, and a frame that is fixed to the frame or the holder And a terminal provided with a contact point that contacts the electrode part of the circuit board, and a guide rail part provided on the frame so as to follow the rotation trajectory of the holder, and the holder A slide part provided on the holder is provided so as to be movable along the guide rail part.

  According to the present invention, the liquid level detection can achieve the intended purpose, suppress the deformation of the holder due to the deformation of the float arm, and suppress the decrease in the reliability of the electrical connection between the circuit board and the contact point. An apparatus can be provided.

The perspective view of the liquid level detection apparatus of 1st Embodiment of this invention. The perspective view of the flame | frame of the liquid level detection apparatus of the embodiment. The side view of the liquid level detection apparatus seen from the arrow X direction in FIG. The perspective view of the holder of the liquid level detection apparatus of the embodiment. The perspective view seen from the back side of the holder of the liquid level detection apparatus of the embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  The liquid level detection device F according to the embodiment of the present invention mainly includes a float arm 1, a holder 2, a frame 3, a circuit board 4, a terminal 5, and an electric cord 6.

  The float arm 1 is formed of an elongated hard steel wire, and includes a float (not shown) that operates following the liquid level at one end thereof, and is bent into a predetermined shape for mounting on the holder 2. In the present embodiment, in order to rotatably support the holder 2 on the frame 3, a shaft portion 1A is provided at the other end.

  In addition, the float which is not illustrated consists of a NBR / phenol foam, for example, has a cylindrical shape. The float floats on the liquid surface and operates following the liquid surface.

  The holder 2 rotates with the movement of the float arm 1, and is made of, for example, polyacetal resin, and includes a plate-shaped base portion 2 </ b> A and an L-shaped holding portion 2 </ b> B that sandwiches the bearing portion 34 of the frame 3. , Locking portions 2C1 and 2C2 that hold the float arm 1, a contact portion 2D that is brought into contact with the stopper portion 32 of the frame 3, and a slide portion 2E.

  The base 2 </ b> A holds the circuit board 4 on the side facing the frame 3. The circuit board 4 has the outer peripheral part of the circuit board 4 fixed by a plurality of hook parts 2A1 provided on the base part 2A. The circuit board 4 is disposed so that the electrode portions formed on the circuit board 4 face the frame 3. Further, locking portions 2C1 and 2C2 are provided on the opposite side of the base portion 2A from the side on which the circuit board 4 is provided, and the shaft portion 1A of the float arm 1 is inserted through the base portion 2A. An insertion hole 2A2 is provided.

  The holding part 2B includes an end part 2B1 and a connecting part 2B2. The end 2B1 is parallel to the base 2A, and the connecting portion 2B2 connects the end 2B1 and the base 2A. The end portion 2B1 is provided with a second insertion hole 2B3 through which the shaft portion 1A of the float arm 1 is inserted.

  The bearing portion 34 of the frame 3 is disposed between the base portion 2A and the end portion 2B1, and the float arm 1 is connected to the first insertion hole 2A2, the second insertion hole 2B3, and the bearing hole 34A provided in the bearing portion 34. By inserting the shaft portion 1 </ b> A, the holder 2 is disposed so as to be rotatable with respect to the frame 3 with the shaft portion 1 </ b> A of the float arm 1 as the rotation center.

  The locking portions 2C1 and 2C2 include a first locking portion 2C1 and a second locking portion 2C2 on the surface side of the base 2A of the holder 2.

  1st latching | locking part 2C1 is provided in the center part of 2 A of base parts of the holder 2, and has comprised C shape so that the float arm 1 can be fitted from the plate | board surface direction of 2 A of base parts of the holder 2. As shown in FIG.

  The second locking portion 2C2 is used to prevent the float arm 1 from being detached from the first locking portion 2C1 after the float arm 1 is mounted on the first locking portion 2C1. It is configured to be elastically deformable in the direction. Accordingly, when the float arm 1 is fitted into the first locking portion 2C1, the second locking portion 2C2 is deformed downward so that the float arm 1 can be guided to the first locking portion 2C1, and the float arm 1 is After fitting into the locking portion 2C1, the second locking portion 2C2 returns to the original position, thereby acting to stop the float arm 1 at the engaging position of the first locking portion 2C1.

  The contact portion 2D extends from a part of the outer periphery of the base portion 2A so as to hang downward, and has contact surfaces 2D1 and 2D2 that contact first and second stoppers 32A and 32B (described later) of the frame 3, respectively. doing.

  The slide part 2E will be described later.

  The frame 3 is made of, for example, polyacetal resin and has a frame shape, and integrally includes a base portion 31, a stopper portion 32, a hook portion 33, a bearing portion 34, and a guide rail portion 36.

  The base portion 31 has three rectangular through holes 3A, 3B, and 3C. Two terminals 5 are exposed in the through holes 3A and 3B, respectively, and are exposed from the through holes 3A and 3B. The electrical cord 6 is crimped by the crimped portion 5B of the terminal 5 thus fixed electrically and physically. Further, the contact 5A of the two terminals 5 is exposed from the frame 3 through the through hole 3C.

  The stopper portion 32 includes a first stopper 32A and a second stopper 32B formed on the side surface of the base portion 31, and the rotation angle of the holder 2, that is, a float arm, between the first and second stoppers 32A and 32B. 1 operating range is defined. The second stopper 32B includes a recess 32B1 into which a projecting piece 2E1 described later of the slide portion 2E enters. By providing the recess 32B1, the contact surface 2D2 of the holder 2 can contact the second stopper 32B, and the rotation range of the holder 2 is not narrowed.

  Three hook portions 33 are provided and can be attached to an attachment member (not shown).

  The bearing portion 34 includes a bearing hole 34A through which the shaft portion 1A of the float arm 1 is inserted. The bearing portion 34 is located between the base portion 2A and the end portion 2B1 of the holder 2, and the shaft portion 1A is inserted through the first insertion hole 2A2, the bearing hole 34A, and the second insertion hole 2B3. The shaft portion 1 </ b> A is rotatably supported by the bearing portion 34, and the holder 2 is rotatably supported with respect to the frame 3.

  The guide rail portion 36 is formed between the first stopper 32 </ b> A and the second stopper 32 </ b> B on the side surface of the base portion 31 so as to follow the rotation locus of the holder 2. Further, the guide rail portion 36 is formed so as to be flush with the upper surface of the base portion 31. Thus, by forming the guide rail portion 36 to be flush with the upper surface of the base portion 31, the slide portion 2E formed on the holder 2 can be provided close to the base portion 2A of the holder 2, The strength of the slide part 2E can be ensured.

  The circuit board 4 is a component in which a conductor material and a resistance material are formed on an insulating substrate by printing and baking, and includes an electrode portion with which the terminal 5 contacts. In this embodiment, it is attached to the holder 2 and interlocks with the float that operates following the liquid level.

  The terminal 5 is made of, for example, a white material. The terminal 5 is affirmed by insert molding on the frame 3, and is integrally provided with a contact 5A and a caulking portion 5B.

  The contact 5A contacts the electrode part of the circuit board 4 and slides on the electrode part.

  The caulking portion 5B holds the electric cord 6 electrically and physically.

  The electric cord 6 is composed of two wires, a ground wire and an output signal wire, and has an oil-resistant cross-linked polyethylene coating.

  The slide portion 2 </ b> E provided on the holder 2 is provided on the holder 2 so that the holder 2 can move along the guide rail portion 36 of the frame 3. In the present embodiment, the slide portion 2E is composed of a protruding piece 2E1 protruding along the plate surface direction of the base 2A at the lower end of the contact portion 2D and a part of the base 2A facing the protruding piece 2E1. The slide portion 2E sandwiches the guide rail portion 36 of the frame 3 between the protruding piece 2E1 and a part of the base 2A facing the protruding piece 2E1. When the slide part 2E moves along the guide rail part 36, the holder 2 can be prevented from being lifted.

  Further, the slide portion 2E, in particular, the protruding piece 2E1 is not located at a projection portion in the longitudinal direction of the rotation axis of the holder 2 of the circuit board 4 (in other words, the normal direction to the plate surface of the base portion 2A of the holder 2). It is provided as follows. This is because when the circuit board 4 is stored and fixed in the base 2A of the holder 2, the circuit board 4 is fixed to the base 2A of the holder 2 from the normal direction of the plate surface of the base 2A without being blocked by the protruding piece 2E1. Therefore, the work of assembling the circuit board 4 to the holder 2 is facilitated. If the protruding piece 2E1 is located even at a part of the projection portion of the circuit board 4 in the longitudinal direction of the rotation axis of the holder 2, the circuit board 4 is used to avoid the protruding piece 2E1 when the circuit board 4 is assembled to the holder 2. 4 will be fixed from the diagonal direction with respect to the plate | board surface direction of 2 A of base parts, workability | operativity is bad and there exists a possibility of reducing productivity.

  Further, the holder 2 includes a projecting portion 2E2 on an opposing surface facing the guide rail portion 36 of the base portion 2A constituting the slide portion E. The projecting portion 2E2 prevents the hook portion 2A1 holding the circuit board 4 of the base portion 2A from coming into contact with the frame 3.

  As described above, the liquid level detection device F of the present invention includes a float arm 1 that includes a float that operates following the liquid level at one end and a shaft portion 1A at the other end, and holds the float arm 1. A holder 2 that includes a stop 2C and rotates with the movement of the float arm 1, a frame 3 that rotatably supports the holder 2, a circuit board 4 that is fixed to the holder 2 or the frame 3, and a frame 3 or In the liquid level detection device F provided with the terminal 5 provided with the contact 5A that is fixed to the holder 2 and is in contact with the electrode portion of the circuit board 4, the frame 3 is provided along the rotation locus of the holder 2. By providing the guide rail portion 36 and the slide portion 2E provided on the holder 2 so that the holder 2 can move along the guide rail portion 36, the float arm 1 is changed. By suppressing deformation of the holder 2, it is possible to provide a liquid level detecting device F, which can suppress the reduction in reliability of electrical connection between the circuit board 4 and the contact point 5A.

  In addition, the circuit board 4 is fixed to the holder 2 and the slide portion 2E is not positioned at a projection portion in the longitudinal direction of the rotation axis of the holder 2 of the circuit board 4, so that the circuit board 4 is assembled to the holder 2. Workability is not impaired.

  Further, the holder 2 is provided with a projecting portion 2E2 on at least one facing surface of the slide portion 2E facing the guide rail portion 36, so that the holder 2 and the frame 3 other than the guide rail portion 36 and the slide portion 2E contact each other. It is possible to prevent the holder 2 from rotating and to maintain good rotation of the holder 2.

  In the embodiment, the circuit board 4 is fixed to the holder 2 and the terminals 5 are fixed to the frame 3. However, the invention is not limited to the embodiment, and the circuit board 4 is attached to the frame 3. It may be fixed and the terminal 5 may be fixed to the holder 2. In this case, the circuit board 4 needs to be electrically connected to the electric cord 6 and the terminals 5 need to be fixed to the holder 2 while being electrically connected to each other.

  INDUSTRIAL APPLICABILITY The present invention can be used for a liquid level detection device that detects the level of fuel in a fuel tank of an automobile.

F liquid level detection device 1 float arm 1A shaft portion 2 holder 2C1 first locking portion 2C2 second locking portion 2E slide portion 2E1 protruding piece 2E2 protruding portion 3 frame 4 circuit board 5 insert terminal 5A contact 6 electric cord 34 bearing Part 36 Guide rail part

Claims (3)

A holder provided with a float that operates following the liquid level at one end and a shaft portion at the other end, and a locking portion that holds the float arm and that rotates with the movement of the float arm A frame that rotatably supports the holder by a bearing portion that rotatably supports the shaft portion, a circuit board that is fixed to the holder or the frame, and a circuit that is fixed to the frame or the holder and that is the circuit And a terminal provided with a contact point that contacts the electrode part of the substrate, a guide rail part provided on the frame so as to follow a rotation trajectory of the holder, and the holder includes the guide rail part And a slide portion provided on the holder so as to be movable along the liquid level. The liquid level detection device according to claim 1, wherein the circuit board is fixed to the holder, and the slide portion is not positioned at a projection portion in a longitudinal direction of a rotation axis of the holder. 3. The liquid level detection device according to claim 1, wherein the holder has a projecting portion provided on a facing surface of a slide portion facing the guide rail portion. 4.

Images