JP5304296B2 - Liquid level detector - Google Patents

Description

  The present invention relates to a liquid level detection device including a float arm that changes a vertical motion associated with a change in the liquid level of a float to a rotational motion, and a detection unit that detects the liquid level in accordance with the rotational motion of the float arm. In particular, the present invention relates to a liquid level detection apparatus in which the detection unit is housed in a sealed state.

  The conventional liquid level detection device includes a float arm that changes the vertical movement accompanying the fluctuation of the liquid level of the float to a rotary motion, and a detection unit that detects the liquid level along with the rotary motion of the float arm, The detection unit was housed in a sealed state in the case (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 6-43008

  The shape of the fuel tank to which the liquid level detection device is fixed varies depending on factors such as the vehicle. In order to use the liquid level detection device for such various types of fuel tanks, for example, a certain vehicle In the fuel tank, the rotation range of the float arm is on the left side of the liquid level detection device, and in the fuel tank of another vehicle, the rotation range of the float arm is relative to the liquid level detection device. In order to be on the right side, dedicated mounting stays are prepared on the left and right, respectively, or the shape of the mounting portion of the liquid level detection device is formed exclusively on the left and right. These resulted in an increase in the number of parts and an increase in cost.

  Accordingly, the present invention focuses on the above-described problems, and an object thereof is to provide a liquid level detection device that can select the rotation range of the float arm from either the left or right side and that does not cause an increase in cost. To do.

The present invention provides a float arm that is mounted with a float that fluctuates up and down as the liquid level fluctuates and changes the vertical fluctuation of the float into a rotational motion, and a detection signal that indicates the liquid level as the float arm moves And a first and second case for housing the detection unit in a sealed state, the liquid level detection device being fixed to an attachment member provided in a fuel tank, A circuit board and a contact member constituting the detection unit are provided in the case, an attachment part fixed to the attachment member is provided in the second case, a contact portion between the first case and the second case, and a positioning part Are point-symmetric.

  According to the present invention, the positioning portion is provided with a contact portion for determining whether or not welding is appropriate when the first and second cases are fixed by welding.

  In the present invention, the positioning portion includes a pin and a hole into which the pin is inserted. The pin is provided in the first case, and the hole is provided in the second case.

  According to the present invention, it is possible to provide a liquid level detection device that can achieve the intended purpose, can select the rotational movement of the float arm from either the left or right side, and does not increase the cost. .

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 rear view of the 1st case of the embodiment. The front view of the 2nd case of the embodiment. The front view of the liquid level detection apparatus of the embodiment. Sectional drawing of the DD line in FIG.

  The liquid level detection device F of the present invention includes a float arm 1, a detection unit 2, an arm holder 3 that holds the float arm 1, a contact holder 4 that holds components of the detection unit 2, and a case 5 that houses the detection unit 2. It is mainly composed.

  The float arm 1 is made of metal, and one end of the float arm 1 is attached to a float 1a that floats on the liquid surface. The other end is held by the arm holder 3.

  The float 1a is made of a metal material that is not easily corroded, such as stainless steel, and fluctuates with the fluctuation of the liquid level. 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 rotates according to the fluctuation of the float 1 a and rotates around a rotation shaft 6 provided in the arm holder 3.

  The detection unit 2 outputs a detection signal indicating a liquid level in accordance with the rotational movement of the float arm 1, and in the present embodiment, is configured by a circuit board 2a and a contact member 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 contact member 2b is made of a conductive metal, has a plurality of contact points, and is fixed to the contact holder 4 by a contact arm 2c made of metal.

  As the float arm 1 rotates, the contact member 2b slides on the plurality of sliding electrodes via the arm holder 3, the contact holder 4 and the contact arm 2c, and outputs a detection signal indicating the liquid level. .

  The arm holder 3 is made of synthetic resin and includes a holding portion 3 a that holds the float arm 1 and a rotating shaft 6. The end of the rotating shaft 6 is fixed to the contact holder 4.

  The contact holder 4 is made of synthetic resin, and in this embodiment, holds the contact member 2b, which 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 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 7 which supports the rotating shaft 6 rotatably is provided. The bearing 7 is a through hole. In addition, the first case 8a includes a wall portion 9 that forms the housing portion 8 formed of a recess in the circuit board 2a. The wall portion 9 is formed without a break, and the end surface 9a of the wall portion 9 is a contact portion that contacts the second case 5b. The end face 9a is rectangular and has a point-symmetric shape.

  The first case 5a is integrally formed with a connector portion 11 having a recess 10. Moreover, the terminal 12 is provided in the 1st case 5a. One end of the terminal 12 is exposed in the storage portion 8 of the first case 5a, and is electrically connected to the circuit board 2a by solder (not shown). Further, the other end of the terminal 12 is exposed in the concave portion 10 of the connector portion 11 and is electrically connected to a connector (not shown) to output a signal output from the detection portion 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. Further, a contact portion 15 rising from the protruding piece 14 is provided around the base of the pin 13a. The contact portion 15 is opposed to a contact portion provided in a second case 5b described later.

The second case 5b is made of a light-transmitting synthetic resin that transmits light. And the wall part 17 which forms the accommodating part 16 which consists of a recessed part is provided. The wall portion 17 is formed without a break, and the end surface 17a of the wall portion 17 is a contact portion that contacts the first case 5b. Incidentally, the end surface 17 a is in the form of which points symmetrically rectangular.

  The end surfaces 9a and 17a 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. Further, a projecting piece 21 and a contact portion 22 rising from the flat plate portion 19 are provided around each of the holes 20a and 20b on the side facing the pins 13a and 13b. The contact portion 22 is opposed to the contact portion 15 of the first case 5a.

  Each contact part 15 and 22 determines whether the amount of melt | dissolution of the 1st, 2nd case 5a, 5b when pressing the 1st, 2nd case 5a, 5b mutually and laser welding is appropriate. In this embodiment, when the contact portions 15 and 22 are in contact with each other, it can be determined that the end faces 9a and 17a are too melted.

  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 pin 13a and the pin 13b are provided in a point-symmetrical position, and the hole 20a and the hole 20b are also provided in a point-symmetrical position. Therefore, as shown in FIGS. 7 and 8, the first case 5 a can be assembled to the second case 5 b by rotating 180 °. In this case, by inserting the pin 13a into the hole 20b and the pin 13b into the hole 20a, the positions of the first case 5a and the second case 5b are determined, and the first case 5a and the second case 5b are Can be assembled.

  With the above configuration, one can be selected from the two assembling directions of the first and second cases 5a and 5b, and the rotation range of the float arm 1 can be selected from either one of both sides. In addition, it is possible to provide the liquid level detection device F that eliminates the need for a dedicated mounting stay or the like and does not increase the cost.

  Reference numeral 24 denotes a sealing member, which is mounted between the rotary shaft 6 and the bearing 7. In the present embodiment, the sealing member 24 is made of fluororubber, and the cross-sectional shape thereof is a V shape. By providing the sealing member 24, the rotating shaft 6 can be disposed in a watertight manner with respect to the bearing 7 of the first case 5a.

  In addition, by providing the pins 13a and 13b in the first case 5a and providing the holes 20a and 20b in the second case 5b, the holes 20a and 20b for accommodating the pins 13a and 13b are provided in the insertion portion 23 of the second case 5b. The liquid level detection device F can be reduced in size.

  The detection unit 2 can be used for a liquid level detection device F in which a case is housed in a sealed state.

F liquid level detector 1 float arm 1a float 2 detector 5a first case body 5b second case body 9a end face (contact portion)
13a, 13b Pin (positioning part)
15 Contact part 17a End surface (contact part)
20a, 20b hole (positioning part)
22 Contact area

Claims (3)

A float arm that is mounted with a float that fluctuates up and down as the liquid level fluctuates and changes the vertical fluctuation of the float into a rotational motion, and a detection signal that outputs the detection signal indicating the liquid level as the float arm rotates And a first and second case for housing the detection unit in a sealed state, and is a liquid level detection device fixed to an attachment member provided in a fuel tank , wherein the detection is performed on the first case. A circuit board and a contact member are provided, a mounting portion fixed to the mounting member is provided in the second case, and a contact portion between the first case and the second case and the positioning portion are point-symmetric. A liquid level detection device characterized by that.
  The liquid level detection device according to claim 1, wherein the positioning portion includes a contact portion that determines whether or not welding is appropriate when the first and second cases are fixed by welding. The liquid level detection device according to claim 1, wherein the positioning portion includes a pin and a hole into which the pin is inserted, the pin is provided in the first case, and the hole is provided in the second case. .

Images