JP2015102501A - Liquid level detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detection device which has the output changed in accordance with fluctuation of a float not to give discomfort to a driver.SOLUTION: A liquid level detection device F includes a float arm 6 having a float at one end part thereof, a holder 2 holding the float arm 6 and a magnet, a body part 1 supporting the holder 2 so as to make the holder 2 turnable, and a detection part for detecting displacement of the magnet. The holder 2 is provided with at least first and second contact parts 24, 25, and 26, and the body part 1 is provided with not only first and second stoppers 1e1 and 1e2 to be brought into contact with the first and second contact parts 24, 25, and 26 but also third and fourth stoppers 4d1 and 4e1 to be brought into contact with the holder 2 or the float arm 6 provided on the holder 2. A turning range defined by the third and fourth stoppers 4d1 and 4e1 is narrower than a turning range defined by the first and second stoppers 1e1 and 1e2, and the detection part detects displacement of the magnet in the turning range defined by the first and second stoppers 1e1 and 1e2.

Description

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

  A conventional liquid level detection device is disclosed in Patent Document 1, for example. The liquid level detection device includes a float arm having a float at the tip, a magnetoelectric conversion element that magnetically detects a movement position of the float arm, and outputs an electric signal at a liquid level corresponding to the movement position of the float. A non-contact type liquid level sensor having a memory for storing the output value of the liquid level. In this memory, the highest position and the lowest position of the set float are the lowest. It is written as the upper liquid level and the lowest liquid level, and the output values corresponding to the uppermost position and the lowermost position of the float are saturated in the area above the uppermost position and the area below the lowermost position, respectively. It is set.

Japanese Patent Laying-Open No. 2005-321263 (see in particular FIG. 2)

  The conventional liquid level detection device sets the output values corresponding to the uppermost position and the lowermost position of the float so as to saturate in the area exceeding the uppermost position and the area below the lowermost position, respectively. Even if it moves beyond the set reference value, the output value corresponding to the set reference value is continuously output. Therefore, the highest position and the lowest position of the float written in the memory are the reference position writing jigs. And the stopper is not used as the reference position for writing the float's uppermost position and lowermost position to the memory, so the float exceeds the uppermost position and the lowermost position and the float arm becomes the stopper. There was a case where it moved up or down until it contacted. Therefore, for example, even if the liquid fuel in the automobile fuel tank is lowered from the full tank state due to the consumption of the liquid fuel and the liquid level of the liquid fuel is lowered and the float is also lowered, in the region exceeding the lowest position. Since it is set so as to saturate, the output of the liquid level detection device does not change as the liquid level drops, which may give the driver a sense of discomfort.

  Therefore, the present invention focuses on the above-mentioned problems, and an object of the present invention is to provide a liquid level detection device in which the output changes as the float changes, and the driver does not feel uncomfortable.

  The liquid level detection device of the present invention includes a float arm having a float at one end, a holder that holds the float arm and a magnetic material, a main body that rotatably supports the holder, and a displacement of the magnetic material. A liquid level detecting device comprising: a detecting unit configured to detect at least a first and a second abutting unit provided on the holder; and a main unit configured to abut on the first and second abutting units. The first and second stoppers are provided, and third and fourth stoppers that are in contact with the holder or the float arm provided on the holder are provided. The rotation range defined by the third and fourth stoppers is The detection unit detects the displacement of the magnetic material in the rotation range defined by the first and second stoppers, which is narrower than the rotation range defined by the first and second stoppers.

  Further, third and fourth stoppers are provided on the cover fixed to the main body.

  With the configuration described above, the present invention can achieve the intended purpose, and can provide a liquid level detection device in which the output changes as the float changes, and the driver does not feel uncomfortable.

The top view of the liquid level detection apparatus of 1st Embodiment of this invention. Sectional drawing of the II-II line | wire in FIG. Sectional drawing of the III-III line in FIG. The top view of the liquid level detection apparatus which shows the float arm rotation range of the embodiment. The top view which removed the cover and the float arm of the liquid level detection apparatus of the embodiment. The top view which removed the cover and the float arm of the liquid level detection apparatus of the embodiment. The figure which shows the output of the detection element of the embodiment.

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

  The liquid level detection device F of the present invention is installed in a fuel tank (not shown) that stores liquid fuel such as gasoline.

  The liquid level detection device F mainly includes a float arm 6 having a float (not shown), a main body portion 1, a holder 2, a detection portion 3 and a cover 4.

  The float arm 6 is made of a metal wire, and includes a float (not shown) that floats on the liquid surface of the liquid fuel in the fuel tank at one end, and is attached to the holder 2 at the other end. The end of the float arm 6 attached to the holder 2 is bent at a substantially right angle, and includes a first end 6a and a second end 6b. The first end 6a is on the end side of the float arm 6, and the second end 6b is on the center side of the float arm 6 from the first end 6a. The float arm 6 transmits the vertical movement of the float accompanying the fluctuation of the liquid level to the holder 2.

  The main body 1 is composed of a first resin body 11 and a second resin body 12.

  The first resin body 11 is made of a resin material such as polyacetal (hereinafter referred to as POM), and incorporates a plurality of terminals 1a by primary molding. A detection unit (magnetic detection element) 3 and an electronic component (noise absorbing capacitor or resistor) 5 are mounted on a portion of the terminal 1 a exposed from the first resin body 11.

  The first resin body 11 in which the detection unit 3 and the electronic component 5 are mounted on the terminal 1a is insert-molded by the second resin body 12 made of the same resin material as the first resin body 11, and the main body 1 is formed. . The first resin body 11 is hermetically sealed by the second resin body 12 together with the terminal 1a, the detection unit 3, and the electronic component 5.

  The main body portion 1 includes a first rotation support portion 1b on which the holder 2 is rotatably supported. The first rotation support portion 1 b is formed integrally with the second resin body 12. The 1st rotation support part 1b is carrying out the column shape, and protrudes in the holder 2 side provided with the magnet 2a. The columnar first rotation support portion 1 b includes a sliding surface having a circular cross-sectional shape perpendicular to the rotation axis S direction of the holder 2. In the main body portion 1 on the rotation axis S of the first rotation support portion 1b, the magnetic detection surface 3a of the magnetic detection element that is the detection portion 3 is disposed in a state of facing the magnet 2a.

  In addition, a positioning boss 1c is provided on the rear surface (opposite to the side where the holder 2 is provided) of the main body 1 to determine a position to be attached to, for example, a fuel pump or a mounting stay. And a hook 1d attached to a mounting stay or the like. Both the positioning boss 1c and the hook 1d are formed integrally with the second resin body 12.

  Further, the main body 1 is provided with a stopper 1e that regulates the rotation range of the holder 2. The stopper 1 e protrudes from the main body 1 toward the holder 2 and has a fan shape with the rotation axis S of the holder 2 as the center. The stopper 1e also serves as the first and second stoppers of the present invention. The stopper surface 1e1 of the stopper 1e is a first stopper, and the stopper surface 1e2 is a second stopper. A first contact portion 24 provided on the holder 2 described later contacts the stopper surface 1e1, and a second contact portion 25 contacts the stopper surface 1e2.

  The manufacturing method of the main-body part 1 inserts the several terminal 1a connected mutually into the 1st resin body 11 by primary shaping | molding, and divides the terminal 1a with a press after insert formation, A detection part is set to this divided | segmented terminal 1a. 3. The electronic component 5 is resistance welded or soldered, and the first resin body 11 is secondarily formed with the second resin body 12, and the main body 1 is completed by the manufacturing method described above.

  The holder 2 is made of a resin material such as POM, and the magnet 2a is fixed by insert molding.

  The magnet 2a is a magnetic body, and is made of, for example, a neodymium-ferrite material. The shape of the magnet 2a is a columnar shape with the rotation axis S of the holder 2 as the center. It has been subjected.

  The holder 2 includes a base portion 2b, a first rotation portion 2b2, a second rotation portion 2b3, a first arm attachment portion 21, second arm attachment portions 22, 23, and a first contact portion 24. And second contact portions 25 and 26. In the present embodiment, two second contact portions 25 and 26 are provided.

  The base portion 2b has a disk shape and is formed so as to spread in a radial direction about the rotation axis S of the holder 2 in a direction perpendicular to the rotation axis S direction of the holder 2.

  One first arm attachment portion 21 and two second arm attachment portions 22 and 23 are provided on the upper surface (the upper surface in FIG. 2) of the base portion 2b. The first and second arm attachment portions 21, 22, and 23 attach the float arm 6 for transmitting the movement of the float that operates in conjunction with the fluctuation of the liquid level to the holder 2. The positional relationship between the first arm attachment portion 21 and the second arm attachment portions 22, 23 is such that the first arm attachment portion 21 is positioned between the two second arm attachment portions 22, 23 and the rotation axis of the holder 2. The angle between the first arm attachment portion 21 and the second arm attachment portions 22 and 23 around S is substantially a right angle.

  The first arm attachment portion 21 is for fixing the first end portion 6a of the float arm 6, and the second arm attachment portions 22, 23 are for fixing the second end portion 6b. In the present embodiment, only the second arm attachment portion 22 is used for fixing the float arm 6, and the second arm attachment portion 23 is not used. The first arm attachment portion 21 includes a through hole 21a. The first end portion 6a is inserted into the through hole 21a and the first end portion 6a is fixed. The second arm attachment portions 22 and 23 are concave portions 22b and 23b provided with openings 22a and 23a in a direction perpendicular to the rotation axis S. As shown in FIG. 2, the recesses 22 b and 23 b are arcs along the outer shape of the float arm 6, and the distance between the openings 22 a and 23 a is smaller than the diameter of the float arm 6, and the second end portion 6b is fixed.

  A holding portion 2b4 and a first rotating portion 2b2 for holding the magnet 2a are provided on the lower surface of the base portion 2b.

  The holding portion 2b4 has a cylindrical shape, and its lower side is narrowed to be smaller than the outer shape of the magnet 2a, and includes a first hole 2b5 through which the magnet 2a is exposed.

  The first rotating part 2b2 is provided below the holding part 2b4. The first rotating part 2b2 has a cylindrical shape, and the hole of the first rotating part 2b2 communicates with the first hole 2b5 of the holding part 2b4. The first rotating portion 2b2 is a sliding receiving surface in which a part of the inner peripheral surface of the cylindrical hole 2b5 slides with the cylindrical outer peripheral sliding surface of the first rotating support portion 1b of the main body portion 1. Thus, the holder 2 is rotatably supported.

  In addition to the 1st, 2nd arm attachment parts 21, 22, and 23, the 2nd rotation part 2b3 is provided in the upper surface of the base part 2b.

  The second rotating part 2b3 has a cylindrical shape and includes a second hole 2b6 through which the magnet 2a is exposed. The 2nd rotation part 2b3 is located above the 1st rotation part 2b2 on both sides of the magnet 2a in the rotation axis direction of the magnet 2a. The central axes of the cylindrical first rotation part 2b2 and the second rotation part 2b3 are on the same axis, and the rotation axis of the magnet 2a is also located on the same axis. In the second rotating portion 2b3, the outer periphery having a circular cross-sectional shape in the direction perpendicular to the rotating axis S direction of the magnet 2a is a sliding surface.

  The holder 2 is arranged so that the magnet 2 a of the holder 2 faces the magnetic detection surface 3 a of the detection unit 3 when the first rotation unit 2 b 2 is fitted to the first rotation support unit 1 b of the main body 1. The change in the magnetic pole of the magnet 2 a accompanying the rotation of the holder 2 can be detected by the detection unit 3. Moreover, the slidability of the holder 2 is improved by comprising the main-body part 1 and the holder 2 with the same resin material.

  A side surface of the base portion 2b of the holder 2 includes one first contact portion 24 that contacts the stopper 1e and two second contact portions 25 and 26. In the case of this embodiment, as shown in FIGS. 4 and 5, the stopper 1 e is located between the first contact portion 24 and the second contact portion 25, and the first contact portion 24 is The holder 2 is in contact with the stopper surface 1e1 which is the first stopper of the stopper 1e, and the second contact portion 25 is in contact with the stopper surface 1e2 which is the second stopper of the stopper 1e. Be regulated. The holder 2 can be rotated between the first contact portion 24 and the second contact portion 25 without the cover 4 being attached.

  The positional relationship between the first arm attachment portion 21 and the first contact portion 24 is such that the first arm attachment portion 21 and the first contact portion 24 pass through the rotation axis S of the holder 2 and rotate. It is provided on a line perpendicular to the axis S. That is, the first arm attachment portion 21 and the first contact portion 24 are provided at point-symmetric positions with the rotation axis S of the holder 2 as the center.

  Further, the second arm attachment portions 22 and 23 are provided between the first arm attachment portion 21 and the first contact portion 24, but the first arm attachment portion 21 is centered on the rotation axis S of the holder 2. The angle between the first contact portion 24 and the second arm attachment portions 22 and 23 is substantially a right angle. That is, the angle formed by the first arm attachment portion 21 and the second arm attachment portions 22 and 23 around the rotation axis S is substantially a right angle, and further, the second arm attachment portions 22 and 23 and the first contact portion The angle formed with the contact portion 24 is also a substantially right angle.

  The detection unit 3 detects a displacement of the magnetic material, and is a magnetic detection element such as a Hall IC, for example, and is electrically fixed to the terminal 1a by laser welding or resistance welding. Further, the detection unit 3 is supplied with power and transmits a detection signal by a lead wire 7 electrically connected to the terminal 1a. The detection unit 3 can detect the displacement of the magnet 2 a in the rotation range defined by the first and second contact portions 24 and 25.

  The cover 4 is made of a resin material such as POM. The cover 4 is fixed to the main body 1 and prevents the holder 2 from falling off. The cover 4 includes a second rotation support portion 4a, a base portion 4b, a top plate portion 4c, and first and second wall portions 4d and 4e.

  As shown in FIGS. 1 and 2, the cover 4 is composed of a base 4b, a top plate 4c, and first and second walls 4d and 4e, and as shown in FIG. Shape.

  The 2nd rotation support part 4a is provided in the top-plate part 4c so that it may protrude below in FIG. The second rotation support portion 4a has a cylindrical shape, and an inner peripheral surface thereof is a sliding receiving surface that slides with a sliding surface on the outer periphery of the second rotation portion 2b3. The 2nd rotation support part 4a supports the 2nd rotation part 2b3 so that rotation is possible. The liquid level detection apparatus F of this embodiment supports the holder 2 by the main body 1 and the cover 4 so as to be rotatable.

  The base 4 b has a flat plate shape, is fixed to the main body 1, and fixes the cover 4 to the main body 1. The base 4b and the main body 1 are fixed by appropriate means such as laser welding.

  The top plate portion 4c has a flat disk shape, and when the liquid level detection device F is viewed from the upper surface as shown in FIG. 1, the upper and lower portions in FIG. A second rotation support portion 4a is provided in the middle of the top plate portion 4c.

  The first and second wall portions 4d and 4e have an arc shape when the liquid level detection device F is viewed from above. The float arm 6 is exposed between the first and second wall portions 4d and 4e. The ends of the first and second wall portions 4d and 4e of the cover 4 correspond to the third and fourth stoppers 4d1 and 4e1 of the present invention. The third and fourth stoppers 4d1, 4e1 are in contact with the float arm 6 and define the rotation range of the holder 2.

  A fixing piece 4d2 is provided at the lower end of the first wall portion 4d (the portion in contact with the main body portion 1). The fixing piece 4d2 is also attached to the main body portion 1 by an appropriate means such as laser welding as in the base portion 4b. It is fixed.

  Thus, the first and second rotating portions 2b2 and 2b3 sandwiching the magnet 2a in the direction of the rotation axis S of the magnet 2a are provided in the holder 2, and the detection unit 3 is arranged in the direction of the rotation axis S of the magnet 2a. 1st rotation support part 1b which supports the 1st rotation part 2b2 of the holder 2 so that rotation is possible is provided in the main-body part 1, is fixed to the main-body part 1, and the 2nd of the holder 2 is arrange | positioned. The holder 2 is rotatably supported by the main body 1 and the cover 4 by a cover 4 including a second rotation support portion 4a that rotatably supports the rotation portion 2b3. The float arm 6 is attached to the holder 2 after the cover 4 is attached to the main body 1.

  1, 4, 5, and 6, the liquid level detection device F of the present invention has the first and second stoppers 4 d 1, 4 e 1 having a rotation range defined by the first, It is narrower than the rotation range defined by the second stoppers 1e1, 1e2.

  Next, a manufacturing method of the liquid level detection device F will be described. First, the writing operation of the output characteristics of the detection unit 3 is started. In FIG. 7, the vertical axis represents the output voltage in unit volts (V), and the horizontal axis represents the rotation angle of the float arm 6.

  In the writing operation, first, a manufacturing facility such as a jig is used to rotatably support the holder 2 on the main body 1.

  Secondly, as shown in FIG. 5, the first contact portion 24 of the holder 2 is brought into contact with the stopper surface 1e1, which is the first stopper, to determine the output characteristic start point 8a1 shown in FIG. In the present embodiment, the output voltage of the detection unit 3 is set to 0.5 V, and the output characteristic with the position rotated by 5 degrees is written in the detection unit 3. At the angle below this starting point 8a1, the output voltage is maintained at 0.5V.

  Third, as shown in FIG. 6, the second contact portion 25 of the holder 2 is brought into contact with the stopper surface 1e2 which is the second stopper, and the end point 8a2 of the output characteristic shown in FIG. 7 is determined. In the present embodiment, the output voltage of the detection unit 3 is set to 4.5 V, and the output characteristic with the position rotated by 90 degrees is written in the detection unit 3. At an angle equal to or greater than the end point 8a2, the output voltage is maintained at 4.5V.

  By writing output characteristics to the detection unit 3 in a state where the first and second contact portions 24 and 25 of the holder 2 are in contact with the first stopper 1e1 and the second stopper 1e2, a conventional float is obtained. As compared with the case where the output characteristic is written to the detection unit 3 after the arm is incorporated, the characteristic variation can be suppressed. Further, when writing the output characteristics to the detection unit 3, it is not necessary to assemble the float or the float arm 6, and the equipment for writing the output characteristics can be downsized.

  The above start point 8a1 and end point 8a2 are connected to obtain an arbitrary output characteristic. In the present embodiment, the output characteristic is such that the start point 8a1 and the end point 8a2 are straight lines.

  Next, the cover 4 is fixed to the main body 1 and the float arm 6 is attached to the holder 2 to complete the liquid level detection device F.

  By mounting the float arm 6, the float arm 6 comes into contact with the third stopper 4d1, and is set as a measurement start point 8b1 of the output characteristic of the detection unit 3. The measurement start point 8b1 is approximately 0.73 V, and is a position where the holder 2 is rotated 10 degrees. In addition, the float arm 6 abuts on the fourth stopper 4e1, and is set as a measurement start point 8b2 of the output characteristic of the detection unit 3. This measurement start point 8b1 is approximately 4.27V, and is a position where the holder 2 is rotated 90 degrees.

  As described above, as shown in FIG. 7, the output is reliably changed with respect to the movement of the float or the float arm 6 in the rotation range from the measurement start point 8b1 to the measurement end point 8b2. The liquid fuel in the fuel tank of the automobile is saturated in the region exceeding the lowest position even when the liquid fuel level drops and the float also drops due to the consumption of the liquid fuel from the full tank state. Therefore, the output of the liquid level detection device does not change as the liquid level is lowered, and there is no possibility that the driver will feel uncomfortable.

  Further, even when a force is applied to the float or the float arm 6 to rotate beyond the measurement start point 8b1 or the measurement end point 8b2, the detection unit 3 can reliably change the output.

  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. In the first embodiment, as shown in FIG. 1, the float arm 6 extends from the liquid level detection device F toward the upper side in FIG. 1. For example, the float arm 6 detects the liquid level toward the lower side in FIG. It is also possible to extend from the device F. In this case, the float arm 6 is attached to the holder 2 by the first arm attachment portion 21 and the second arm attachment portion 23, and between the first contact portion 24 and the second contact portion 26 of the holder 2. The holder 2 is assembled to the liquid level detection device F so that the stopper 1e is positioned at the bottom, and the float arm 6 may be provided from between the lower side of the first wall portion 4d and the second wall portion 4e in FIG. .

  In the first embodiment, the first wall portion 4d and the second wall portion 4e of the cover 4 are the third and fourth stoppers 4d1, 4e1, but the main body portion 1 is provided with the third and fourth stoppers. It may be provided.

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

F liquid level detection device 1 main body 1a terminal unit 1b first rotation support 1c positioning boss 1d hook 1e stopper 1e1 stopper surface 1e2 stopper surface 2 holder 2a magnet 2b base 2b2 first rotation unit 2b3 second rotation unit 2b4 Holding portion 2b5 First hole 2b6 Second hole 21 First arm attachment portion (arm attachment portion)
21a Through hole 22 Second arm attachment part (arm attachment part)
22a opening 22b recess 23 second arm mounting portion 23a opening 23b recess 24 first contact portion 25 second contact portion 26 second contact portion 3 detection portion (magnetic detection element)
3a Magnetic detection surface 4 Cover 4a 2nd rotation support part 4b Base part 4c Top plate part 4d 1st wall part 4d1 3rd stopper 4e 2nd wall part 4e1 4th stopper 5 Electronic component 6 Float arm 6a 1st end part 6b Second end portion 7 Lead wire 11 First resin body 12 Second resin body S Rotating shaft

Claims (2)

A float arm provided with a float at one end; a holder for holding the float arm and a magnetic material; a main body that rotatably supports the holder; and a detection unit for detecting displacement of the magnetic material. In the liquid level detection device,
The holder is provided with at least first and second contact portions, the main body portion is provided with first and second stoppers that contact the first and second contact portions, and the holder or the holder is provided with The third and fourth stoppers that contact the provided float arm are provided, and the rotation range defined by the third and fourth stoppers is narrower than the rotation range defined by the first and second stoppers. The detection unit detects a displacement of the magnetic material in a rotation range defined by the first and second stoppers. The liquid level detection apparatus according to claim 1, wherein the third and fourth stoppers are provided on a cover fixed to the main body.

Images