JP2011064620A - Liquid level detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve miniaturization by shortening the length in the direction of the rotating axis of a float arm. <P>SOLUTION: A liquid level detector F includes the float arm 1 which is displaced by floating on a liquid surface, a circuit board 2a having a resistor, a sliding contact point 2b which slides on the circuit board 2a in accordance with the displacement of the float arm 1, and a case 5 for housing the circuit board 2a and the sliding contact point 2b in sealed condition. The liquid level detector F further includes a first holder 3 having a mounting portion 3a for holding the float arm 1 and the rotating axis 6, a packing 24 mounted on the rotating axis 6, a bearing portion 7 which rotatably supports the rotating axis 6 and is disposed in the case 5, a housing portion 25 being disposed at the opening of the bearing portion 7 and housing the packing 24, and a second holder 4 which holds the sliding contact point 2b and rotates with the rotating axis 6 by being fixed to the rotating axis 6, wherein a connecting portion 3b is disposed in the first holder 3, which connects the mounting portion 3a and the rotating axis 6 so that the mounting portion 3a is positioned outside of the housing portion 25. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid level detection device in which a detection unit is stored in a sealed state.

  A conventional liquid level detection device includes a float that floats on a liquid level, a float arm that is displaced by the float, a circuit board that includes a resistor, and a slide that slides on the circuit board as the float arm is displaced. It was provided with the case which accommodates the detection part which consists of a moving contact and the said circuit board and the said sliding contact in the airtight state (for example, refer patent document 1).

Japanese Patent Laid-Open No. 6-43008

  The conventional liquid level detection device is provided with a packing such as an oil seal around the rotation shaft serving as the rotation center of the float arm so that fuel or the like does not enter the sealed case. This packing was provided outside the case. Further, the float arm has one end of the float arm inserted into the rotation shaft in the direction of the rotation axis of the rotation shaft.

  Since the conventional liquid level detection device has a structure in which one end of the packing and the float arm is stacked in the rotation axis direction of the float arm, the liquid level detection device becomes longer in the rotation axis direction of the float arm. There has been a problem that the detection device becomes thick in the direction of the rotation axis of the float arm.

  When the liquid level detection device is increased in size, for example, when the liquid level detection device is thickened, there is a problem that it becomes difficult to put the liquid level detection device into the fuel tank when the liquid level detection device is put into the fuel tank. Therefore, downsizing of the liquid level detection device has been desired.

  Therefore, the present invention pays attention to the above-mentioned problems, and in the liquid level detection device in which the detection unit is housed in a sealed case, it is possible to reduce the length of the float arm in the rotation axis direction and to reduce the size. An object is to provide a liquid level detection device.

  The present invention includes a float that floats on a liquid surface, a float arm that is displaced by the float, a circuit board that includes a resistor, and a sliding contact that slides on the circuit board as the float arm is displaced, In a liquid level detection device comprising a case for housing the circuit board and the sliding contact in a sealed state, a first holder having a mounting portion for holding the float arm and a rotating shaft, and mounting on the rotating shaft A packing, a bearing that rotatably supports the rotating shaft and that is provided in the case, a storage that is provided in an opening of the bearing and that stores the packing, and holds the sliding contact A second holder fixed to the rotating shaft and rotating together with the rotating shaft, and connecting the mounting portion and the rotating shaft so that the mounting portion is positioned outside the storage portion The in which provided on the first holder.

  In the present invention, the storage portion is a wall formed around the opening.

  In the present invention, the wall has a cylindrical shape.

  In the present invention, the surface on which the mounting portion is provided faces in the circumferential direction of the case.

  According to the present invention, the intended purpose can be achieved, and in the liquid level detection device in which the detection unit is housed in a sealed case, the length of the float arm in the rotation axis direction can be shortened and the size can be reduced. A liquid level detecting device can be provided.

The front view of the liquid level detection apparatus of 1st Embodiment of this invention. Sectional drawing of the AA line in FIG. Sectional drawing of the BB line in FIG. The side view seen from the arrow C direction in FIG.

  The liquid level detection device F of the present invention houses a float 1a, a float arm 1, a detection unit 2, a first holder 3 that holds the float arm 1, a second holder 4 that is fixed to the first holder 3, and a detection unit 2. The case 5 is mainly configured.

  The float 1a is made of a metal material that is not easily corroded, such as stainless steel, floats on the liquid surface, and is displaced along with the displacement of the liquid surface. In addition, the material of the float 1a is not limited to this embodiment, You may form with a synthetic resin etc.

  The float arm 1 is made of metal, and one end thereof is attached to the float 1a. The other end is held by the first holder 3.

  The float arm 1 rotates in accordance with the displacement of the float 1 a and rotates around the rotation shaft 6 provided in the first holder 3.

  An end portion 1b held by the first holder 3 of the float arm 1 is bent at a right angle with respect to the main portion 1c.

  The detection unit 2 outputs a detection signal indicating the liquid level with the rotational movement of the float arm 1, and in the present embodiment, is configured by a circuit board 2a and a sliding contact 2b.

  The circuit board 2a is a ceramic substrate, which is an insulating base material, provided with a resistor and a sliding electrode (not shown). A plurality of the sliding electrodes are provided, and each of the sliding electrodes is electrically connected to the resistor independently.

  The sliding contact 2b is made of a conductive metal, has a plurality of contact points, and is fixed to the second holder 4 by a contact arm 2c made of metal.

  As the float arm 1 rotates, the sliding contact 2b slides on the plurality of sliding electrodes via the first holder 3, the second holder 4, and the contact arm 2c, and indicates a liquid level. Is output.

  The first holder 3 is made of synthetic resin and includes a mounting portion 3a that holds the float arm 1, a rotating shaft 6, and a connecting portion 3b. The first holder 3 is fixed to the second holder 4 at the end of the rotating shaft 6. In addition, the packing 24 mentioned later is arrange | positioned so that the base of the rotating shaft 6 may be surrounded.

  The second holder 4 is made of a synthetic resin, and in this embodiment, holds the sliding contact 2b that is a part of the components of the detection unit 2 via the contact arm 2c.

  The case 5 includes a first case 5a and a second case 5b. The case 5 houses the circuit board 2a and the sliding contact 2b constituting the detection unit 2 in a sealed state.

  The first case 5a is made of a light-shielding synthetic resin that does not transmit light. And the bearing part 7 which supports the rotating shaft 6 rotatably is provided. The bearing portion 7 is a through hole. The first case 5a includes a wall portion 9 that forms a storage portion. The wall portion 9 is formed without a break.

  The first case 5a is integrally formed with a female connector portion 11 formed of a recess. Further, the terminal 12 is provided in the first case 5 a so as to be exposed from the connector portion 11. The other end of the terminal 12 is exposed in the housing portion of the first case 5a, and is electrically connected to the circuit board 2a by solder (not shown). The terminal 12 is electrically connected to a connector (not shown), and outputs a signal output from the detection unit 2 to the outside.

  Further, the first case 5a is provided with two pins 13a and 13b as positioning portions for determining the assembly position of the first case 5a and the second case 5b. The pin 13 a is provided on the protruding piece 14 protruding from the wall portion 9 of the first case 5 a, and the pin 13 b is provided on the connector portion 11.

  The second case 5b is made of a light-transmitting synthetic resin that transmits light. And the wall part 17 which forms a storage part is provided. The wall portion 17 is formed without a break.

  The end surfaces of the wall portions 9 and 17 of the first and second cases 5a and 5b are brought into contact with each other and welded with a laser to be in a sealed state.

  The second case 5b includes three attachment portions 18 that are fixed to an attachment member (not shown) provided in the fuel tank. One attachment portion 18 is provided at the center of the second case 5b and two attachment portions 18 are provided on the upper side in FIG. . This attachment part 18 is comprised by the leg part 18a which has elasticity, and the nail | claw part 18b provided in the front end side. In addition, the leg part 18a of the two attachment parts 18 provided in the upper side in FIG. 1 is provided in the flat plate part 19 which protruded and formed in the upper side in FIG. 1 from the 2nd case 5b. By hooking the claw portion 18b of the mounting portion 18 on the mounting member, the liquid level detection device F is fixed to the mounting member.

  Further, the second case 5b is provided with two holes 20a and 20b as positioning portions for determining the assembly position of the first case 5a and the second case 5b. The holes 20a and 20b are provided in the insertion portion 23 serving as a positioning portion that determines the attachment position between the liquid level detection device F and the attachment member. The hole 20 a is provided in the protruding piece 21 protruding from the second case 5 b, and the hole 20 b is provided in the flat plate portion 19.

  By inserting the pin 13a constituting the positioning portion into the hole 20a and inserting the pin 13b into the hole 20b, the positions of the first case 5a and the second case 5b can be determined, and the position at the time of laser welding is determined. It is possible to prevent positional displacement when the two first cases 5a and the second case 5b are welded.

  The first case 5 a is provided with a storage portion 25 that stores the packing 24 attached to the rotary shaft 6. The storage portion 25 is a cylindrical wall and is provided outside the first case 5a so as to surround the opening of the bearing portion 7 formed of a through hole.

  The packing 24 is mounted between the rotary shaft 6 and the storage unit 25. In the present embodiment, the sealing member 24 is made of fluororubber, has a ring shape, and has a V-shaped cross section. By providing the sealing member 24, the rotating shaft 6 can be disposed in a watertight manner with respect to the bearing portion 7 of the first case 5a.

  The mounting portion 3a for holding the float arm 1 of the first holder 3 includes a mounting plate portion 3a1 having a mounting surface, a through hole 3a2 through which an end 1b of the float arm 1 passes, and an outer periphery of a main portion 1c of the float arm 1. The through-hole 3a1 and the locking part 3a2 are arranged on the mounting surface of the mounting plate part 3a1 so as to face the peripheral direction of the case 5 instead of the case 5 side. Is formed. The mounting portion 3 a is located outside the storage portion 25, and the mounting plate portion 3 a 1 of the mounting portion 3 a is positioned on the case 5 side from the root of the rotating shaft 6 with respect to the axial direction of the rotating shaft 6. is doing.

  By configuring as described above, it is possible to provide the liquid level detection device F that can shorten the length of the float arm 1 in the rotation axis direction and can be downsized.

  Moreover, the float arm 1 can be easily fixed to the mounting part 3a because the surface on which the mounting part 3a is mounted faces in the circumferential direction of the case 5 that is opposite to the case 5 side.

  It can be used for a liquid level detection device in which the detection unit is housed in a sealed state.

F liquid level detector 1 float arm 1a float 2 detector 2a circuit board 2b sliding contact 3 first holder 3a mounting portion 3b connecting portion 4 second holder 5 case 6 rotating shaft 7 bearing portion 24 packing 25 storage portion

Claims (4)

A float that floats on a liquid surface; a float arm that is displaced by the float; a circuit board that includes a resistor; a sliding contact that slides on the circuit board as the float arm is displaced; and the circuit board; In a liquid level detection device including a case for storing the sliding contact in a sealed state, a first holder including a mounting portion for holding the float arm and a rotating shaft, and a packing mounted on the rotating shaft; A rotating shaft that rotatably supports the rotating shaft, a bearing portion provided in the case, a storage portion that is provided in an opening of the bearing portion and stores the packing, and that holds the sliding contact and is attached to the rotating shaft. A second holder that is fixed and rotates together with the rotary shaft, and a connecting portion that connects the mounting portion and the rotary shaft so that the mounting portion is positioned outside the storage portion. Liquid level detecting device, characterized in that provided on the holder.
The liquid level detection device according to claim 1, wherein the storage portion is a wall formed around the opening. The liquid level detection device according to claim 2, wherein the wall has a cylindrical shape. The liquid level detection device according to claim 1, wherein a surface on which the mounting portion is provided faces in a circumferential direction of the case.

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