JP6388836B2 - Liquid level detector - Google Patents

Description

  The technology disclosed in the present specification relates to a liquid level detection device that detects a liquid level of a liquid.

  Patent Document 1 discloses a liquid level detection device including a float, a float arm, a magnet that is displaced with the operation of the float arm, a magnetic detection element that detects a magnetic change of the magnet, and a terminal. . A part of the terminal is exposed and covered with a resin coating, and a seal film is provided between the terminal and the coating. A V-shaped notch groove is formed at the apex where the front and rear surfaces of the plate-like terminal intersect with both side surfaces. The notch groove secures the thickness of the seal film and improves the liquid tightness of the seal film. As a result, it is possible to prevent liquid such as fuel from entering the inside.

JP 2014-98684 A

  In this type of liquid level detection device, the covering portion covering the terminal is formed by insert molding. That is, the covering portion is formed by filling the mold with resin while a part of the terminal is inserted into the mold. For this reason, when shaping | molding a coating | coated part, the external force from resin with which a metal mold | die is filled acts on the surface of a terminal. In the liquid level detection device of Patent Document 1, the seal film only covers the outer surface of the terminal. For this reason, when the covering portion is molded, the seal film may be peeled off from the surface of the terminal due to the flow of the resin filled in the mold.

  The present specification provides a technique for suppressing the sealing film from peeling off from the terminal when the covering portion is formed.

  A liquid level detection device disclosed in this specification includes a float, an arm member attached to the float, which converts a vertical motion of the float into a rotational motion, and a detection element that detects the rotational motion of the arm member. A terminal whose one end is electrically connected to the detection element, a resin covering portion covering a part of the terminal, and a covering portion of the terminal covered by the covering portion. And a sealing film for sealing between the two. A through hole is provided in the covering portion of the terminal, and a seal film is also provided in the through hole.

  In the above liquid level detection device, a seal film is also provided inside the through hole. The seal film provided on one surface is combined with the seal film provided on the other surface by the seal film provided inside the through-hole. For this reason, compared with the case where the sealing film is simply provided on the outer surface of the terminal, the resistance force increases against the external force that attempts to peel the sealing film from the terminal. Therefore, it can suppress that a sealing film peels from a terminal.

The figure which shows the whole structure of a liquid level detection apparatus. The II-II sectional view taken on the line of the detection part of the liquid level detection apparatus in FIG. The front view of the single-piece | unit of the primary molded product incorporated in a detection part (state after sealing film formation). FIG. 4 is a sectional view taken along line IV-IV of a terminal located in the center in FIG. The figure which combines and shows the perspective view (state before sealing film formation) of the primary molded article, and the enlarged part of the part A which is the part. The front view of the single-piece | unit of a primary molded product (state before sealing film formation). The VII-VII sectional view taken on the line of the terminal located in the center in FIG. VIII-VIII sectional view of the terminal located in the center in FIG.

  The main features of the embodiments described below are listed. The technical elements described below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Feature 1) The liquid level detection device disclosed in the present specification may further include a storage member that stores the detection element. In this case, the housing member may be covered with the covering portion. According to such a configuration, since the detection element is protected by both the housing member and the covering portion, it is possible to suitably suppress contact between the detection element and the liquid. In addition, when the liquid is a mixture, it is possible to suitably prevent the mixed liquid from coming into contact with the detection element by properly using the material corresponding to the permeability of each liquid in the covering portion and the accommodating member.

(Characteristic 2) In the liquid level detection device disclosed in the present specification, the terminal extends from the surface of the detection element in a direction away from the detection element, and the through hole is provided on the detection element side in the covering portion. It may be. According to such a configuration, if the covering portion is formed by flowing the resin from the detection element side toward the terminal side, the resistance force of the seal film can be increased on the upstream side of the resin flow. For this reason, it can suppress suitably that a sealing film peels from a terminal.

(Feature 3) In the liquid level detection device disclosed in this specification, the terminal may be a plate-shaped member. The covering portion of the terminal may have a narrow portion having a small size in the width direction orthogonal to the extending direction and the thickness direction of the terminal and a wide portion having a wide size in the width direction orthogonal to the extending direction and the thickness direction. And a narrow part and a wide part may be alternately arrange | positioned in the extending | stretching direction. According to such a configuration, since grooves are formed on both side surfaces of the terminal, the sealing film and the terminal can be firmly bonded. Thereby, it can suppress suitably that a sealing film peels from a terminal.

(Feature 4) In the liquid level detection device disclosed in the present specification, the through hole may be provided in the wide portion and may extend in the thickness direction. According to such a configuration, the seal film portion covering one surface orthogonal to the thickness direction of the terminal and the seal film portion covering the other surface are portions of the seal film provided in the through hole. The area to be connected via the is increased. Therefore, the effect of preventing the sealing film from peeling off from the terminal can be enhanced.

(Feature 5) In the liquid level detection device disclosed in this specification, the minimum cross-sectional area of the terminal when the terminal is cut in a plane perpendicular to the extending direction within the range in which the through-hole is provided, the terminal is narrow. It may be larger than the cross-sectional area of the terminal when cut by a plane perpendicular to the extending direction at the part. According to such a configuration, since the magnitude of the electrical resistance is inversely proportional to the cross-sectional area, it is possible to prevent the terminal from suppressing heat generation and reducing mechanical strength.

  A liquid level detection device 10 according to an embodiment will be described with reference to the drawings. As shown in FIG. 1, the liquid level detection device 10 is used for detecting the fuel liquid level position of the fuel 52 stored in a fuel tank 50 of an automobile or the like. The liquid level detection device 10 includes a float 12, an arm member 14, and a detection unit 15 that are disposed in the fuel tank 50, a fuel meter 60 and a mold resin unit 20 that are disposed outside the fuel tank 50.

  A fuel pump unit 11 is disposed in the fuel tank 50. The fuel pump unit 11 is attached to the set plate 8 that closes the opening of the fuel tank 50. The fuel pump unit 11 sucks the fuel in the fuel tank 50 into the fuel pump unit 11, boosts the fuel, and discharges the fuel outside the fuel pump unit 11. The fuel discharged from the fuel pump unit 11 is supplied from the discharge port 6 to an internal combustion engine (not shown). When the fuel in the fuel tank 50 is supplied to the internal combustion engine, the liquid level of the fuel in the fuel tank 50 changes.

  The float 12 is formed of a material having a specific gravity smaller than that of the fuel 52. The float 12 floats on the fuel 52 in the fuel tank 50 and moves in the vertical direction according to the liquid level of the fuel 52. The float 12 is rotatably attached to the tip of the arm member 14. The base end of the arm member 14 is rotatably supported by the detection unit 15. When the float 12 moves in the vertical direction according to the fuel level in the fuel tank 50, the arm member 14 swings and rotates with respect to the detection unit 15.

  The arm member 14 is formed of a metal having resistance to a fuel such as stainless steel. The float 12 is attached to one end 14 a of the arm member 14. The other end 14 b of the arm member 14 is rotatably held by the detection unit 15.

  The detector 15 is attached to the fuel pump unit 11. The detector 15 is connected to a fuel meter 60 outside the fuel tank 50 by three wires 7 (that is, a power supply line, a ground line, and a signal line) that penetrate the set plate 8. The detection unit 15 is operated by a power source supplied from the outside, and detects the rotation angle of the arm member 14. The detection result of the detection unit 15 is input to the fuel meter 60 via the wire 7. The detailed configuration of the detection unit 15 will be described in detail later.

  The fuel meter 60 includes a CPU 64 and a display 62. The CPU 64 calculates the liquid level of the fuel 52 in the fuel tank 50 based on the detection result input from the detection unit 15 via the wire 7 (specifically, a signal line), and the calculated liquid level. From this, the amount of fuel stored in the fuel tank 50 is calculated. The CPU 64 displays the calculated fuel amount on the display 62. The indicator 62 is disposed in the driver's seat of the automobile. By displaying the amount of fuel in the fuel tank 50 on the display 62, the driver can appropriately grasp the amount of fuel in the fuel tank 50.

  Next, the detection unit 15 will be described in detail. As shown in FIG. 2, the detection unit 15 includes a primary molded product 17 and a mold resin unit 20 that covers the primary molded product 17.

  The mold resin portion 20 protects the primary molded product 17 (specifically, the magnetic detection element 16 accommodated in the primary molded product 17) from the fuel 52. The mold resin part 20 is formed of a resin material (for example, PPS). A recess 30 is formed on one surface (the upper surface in FIG. 2) of the mold resin portion 20. A magnet 32 is accommodated in the magnet accommodating portion of the cover 31 corresponding to the inside of the recess 30. The magnet 32 is held in the recess 30 so as to be rotatable around its rotation axis. The magnet 32 is connected to the arm member 14 and rotates according to the swinging rotation of the arm member 14. Accordingly, when the arm member 14 swings and rotates according to the fuel level in the fuel tank 50, the magnet 32 rotates in the recess 30 accordingly. The upper surface of the recess 30 is closed by a cover 31. That is, the upper surface of the recess 30 is closed by the cover 31 that houses the magnet 32. The mold resin part 20 is formed with an insertion port 21 into which one end of the wire 7 is inserted.

  The primary molded product 17 includes a magnetic detection element 16, a terminal 18, and a housing member 38. The magnetic detection element 16 is disposed at a position facing the magnet 32 and measures the magnitude of the magnetic field generated by the magnet 32. That is, the magnetic detection element 16 outputs a signal proportional to the magnetic flux density that passes through the magnetic detection element 16. The density of magnetic flux passing through the magnetic detection element 16 varies depending on the relative positional relationship between the magnet 32 and the magnetic detection element 16. For this reason, when the magnet 32 rotates in the mold resin portion 20 according to the swinging rotation of the arm member 14, the magnetic flux density passing through the magnetic detection element 16 changes and the signal output from the magnetic detection element 16 changes. . Thereby, the swinging rotation of the arm member 14 is detected, and the liquid level and the liquid amount of the fuel in the fuel tank 50 are specified. For the magnetic detection element 16, for example, a known sensor using a Hall IC can be used.

  One end of the terminal 18 is electrically connected to the magnetic detection element 16. A part of one end side of the terminal 18 is located inside the accommodating member 38, and the other part is located outside the accommodating member 38. A part of the terminal 18 located outside the housing member 38 is covered with the mold resin portion 20. The portion not covered with the mold resin portion 20 is located in the insertion port 21 of the mold resin portion 20. When one end of the wire 7 is inserted into the insertion port 21, the wire 7 and the terminal 18 are connected. The detailed configuration of the terminal 18 will be described in detail later.

  The housing member 38 is formed of a resin material (for example, epoxy resin). The magnetic detection element 16 and a part of the terminal 18 are accommodated inside the accommodating member 38. The terminal 18 protrudes from one end surface of the housing member 38. The outer peripheral surface of the housing member 38 is covered with the mold resin portion 20.

  In the present embodiment, the housing member 38 is provided in the mold resin portion 20, so that even when a mixed fuel (a fuel in which a plurality of types of fuel is mixed) is used as the fuel 52, the fuel 52 is added to the magnetic detection element 16. It can prevent suitably contacting. That is, the mold resin portion 20 and the housing member 38 can be formed of different materials according to the type of fuel, and the contact between the fuel 52 and the magnetic detection element 16 can be suitably prevented. For example, when the mold resin portion 20 is formed of PPS and the housing member 38 is formed of epoxy resin, PPS has low alcohol permeability, and epoxy resin has low gasoline permeability. For this reason, when the fuel 52 is a mixed fuel of gasoline and alcohol, the mold resin portion 20 can prevent alcohol from infiltrating, and the housing member 38 can prevent gasoline from infiltrating. As a result, such mixed fuel 52 can be suitably prevented from coming into contact with the magnetic detection element 16.

  Next, the terminal 18 will be described in detail. As shown in FIG. 3, the terminal 18 is formed of a plate-like member made of a conductive material. Three terminals 18 are provided corresponding to the three terminals of the magnetic detection element 16. Each terminal 18a, 18b, 18c is electrically connected to the magnetic detection element 16, and each of three wires 7 (power supply line, ground line, signal line) is connected thereto. For this reason, the magnetic detection element 16 and the fuel meter 60 are electrically connected by the terminal 18 and the wire 7, and a signal from the magnetic detection element 16 is transmitted to the fuel meter 60.

  As shown in FIG. 3, the terminals 18 a, 18 b and 18 c are provided so as to protrude from one end face of the housing member 38. Since the magnetic detection element 16 is accommodated in the accommodating member 38, it can be said that the terminals 18a, 18b, 18c extend from the magnetic detection element 16 side in a direction away from the magnetic detection element 16. Specifically, the terminal 18a is bent laterally at the proximal end portion 19b, and the distal end portion 19a extends upward. The terminal 18b extends linearly upward from the proximal end portion 19b to the distal end portion 19a without being bent. The terminal 18c is bent laterally (on the opposite side to the terminal 18a) at the base end portion 19b, and the tip end portion 19a extends upward. The tip portions 19a of the terminals 18a, 18b, and 18c are exposed to the outside from the mold resin portion 20 and protrude into the insertion port 21. The base end portion 19b of each terminal 18a, 18b, 18c is located inside the mold resin portion 20 and is covered with the mold resin portion 20 (see FIG. 2). As is apparent from FIG. 3, a seal film 22 is formed on the base end portion 19b of each terminal 18a, 18b, 18c.

  The sealing film 22 is provided on the surface of the base end portion 19b of each terminal 18a, 18b, 18c, and seals between each terminal 18a, 18b, 18c and the mold resin portion 20. The sealing film 22 can be formed, for example, by applying a primer to the surface of each terminal 18a, 18b, 18c by using a syringe and drying at a high temperature. The primer is, for example, a sealing material such as hydrin rubber made into a liquid state with a solvent such as toluene. The sealing film 22 prevents fuel and the like from entering the mold resin portion 20 through the terminals 18a, 18b, and 18c.

  Here, a through hole 23 is formed in the base end portion 19b of each terminal 18a, 18b, 18c, and a seal film 22 is also formed in the through hole 23. In addition, since the structure of the part in which the sealing film 22 was formed in the terminals 18a, 18b, and 18c is the same, the terminal 18b will be described as an example here.

  As shown in FIG. 5, narrow portions 40a to 40d having small dimensions in the width direction (x direction) orthogonal to the extending direction (y direction) and the thickness direction (z direction) of the terminal 18 are provided at the base end portion of the terminal 18b. And the wide part 42a-42c with a large dimension of the width direction (x direction) is provided. As shown in FIGS. 7 and 8, the narrow portions 40a to 40d are thinner than the wide portions 42a to 42c. The narrow portions 40a to 40d and the wide portions 42a to 42c are alternately arranged in the extending direction of the terminal 18b. That is, in order from the housing member 38 side, the wide portion 42a is disposed next to the narrow portion 40a, and the narrow portion 40b is disposed next to the wide portion 42a. Hereinafter, the wide portion 42b, the narrow portion 40c, the wide portion 42c, and the narrow portion The part 40d is arranged. Since the wide portions 42a to 42c and the narrow portions 40a to 40d are alternately provided on the terminal 18b, V-shaped grooves 44 are formed on both side surfaces of the terminal 18b.

  As is clear from FIG. 5, the through hole 23 is formed in the wide portion 42 a located on the housing member 38 side (that is, the magnetic detection element 16 side). As shown in FIG. 7, the through-hole 23 extends the wide part 42a in the thickness direction and penetrates the wide part 42a. As shown in FIGS. 7 and 8, the width and thickness of the wide portion 42a are made larger than the width and thickness of the narrow portion 40b, respectively. For this reason, also in the wide part 42a in which the through-hole 23 was formed, the cross-sectional area is made larger than the cross-sectional area of the narrow parts 40a-40d. That is, the cross-sectional area of the terminal 18b when the terminal 18b is cut along the plane orthogonal to the extending direction in the wide portion 42a is the same as that of the terminal 18b when the terminal 18b is cut along the plane orthogonal to the extending direction at the narrow portions 40a to 40d. It is larger than the cross-sectional area. The magnitude of the electrical resistance is inversely proportional to the cross-sectional area of the terminal 18b. For this reason, by adjusting the cross-sectional area of the terminal 18b as described above, the through hole 23 prevents the terminal 18b from suppressing heat generation and lowering the mechanical strength.

  As apparent from FIGS. 3 and 4, the seal film 22 is formed on the portion of the terminal 18 b where the narrow portions 40 a to 40 d and the wide portions 42 a to 42 c are formed. As shown in FIG. 4, the sealing film 22 is also formed in the through hole 23 in the wide portion 42 a. For this reason, the seal film 22 formed on the surface of the terminal 18 b and the seal film 22 formed on the back surface of the terminal are connected by the portion 22 b located in the through hole 23 of the seal film 22.

  The mold resin portion 20 described above is formed by insert molding using the primary molded product 17 as an insert material. That is, the mold resin portion 20 is molded by filling the mold with molten resin in a state where a part of the primary molded product 17 is inserted into the mold. When the molten resin is filled in the mold, an external force is generated to peel off the sealing film 22 from the terminal 18 due to the flow of the molten resin. Here, a through hole 23 is formed in the terminal 18, and the seal film 22 is also formed in the through hole 23. For this reason, the sealing film 22 is firmly fixed to the terminal 18 at the portion 22 b formed in the through hole 23, and is prevented from being peeled off from the terminal 18. Further, since the V-shaped groove 44 is formed on the surface of the terminal 18, the terminal 18 and the seal film 22 are firmly coupled also by the groove 44. This also suppresses the sealing film 22 from being peeled off from the terminal 18.

  When the mold resin portion 20 is molded, if the molten resin is filled into the mold so that the molten resin flows from the housing member 38 side of the primary molded product 17 toward the tip of the terminal 18, the molten resin and the terminal 18 are filled. Means contact from the narrow portion 40a and the wide portion 42a side. A through hole 23 is formed in the wide portion 42a, and the bonding strength between the terminal 18 and the seal film 22 is enhanced. For this reason, the connection between the terminal 18 and the seal film 22 can be firmly maintained during the period in which the molten resin is filled in the mold.

  In the liquid level detection device 10 described above, the terminal 18 and the sealing film 22 are firmly coupled, and the sealing film 22 is prevented from peeling off from the terminal 18 when the mold resin portion 20 is molded. For this reason, the space | interval between the terminal 18 and the mold resin part 20 is favorably sealed, and the magnetic detection element 16 and the fuel 52 are preferably suppressed from contacting each other. Thereby, the magnetic detection element 16 can be operated normally over a long period of time.

  The above-described embodiment is an embodiment that embodies the present invention, and the present invention is not limited to such a form. For example, in the above-described embodiment, only one through hole 23 is provided in the terminal 18, but a plurality of through holes may be formed in the terminal. Further, the shape of the terminal 18 and the cross-sectional shape of the through hole can be changed as appropriate.

  Further, in the above-described embodiment, the signal from the magnetic detection element 16 is directly input to the fuel meter 60, and the liquid level of the fuel 52 in the fuel tank 50 is specified in the fuel meter 60 and stored in the fuel tank 50. The amount of fuel being used was calculated. However, the fuel amount may be calculated by the detection unit 15 from the detection signal of the magnetic detection element 16, and a signal corresponding to the calculated fuel amount may be output to the fuel meter 60.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Further, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Moreover, the technique illustrated in this specification or the drawings achieves a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

6: Discharge port 7: Wire 8: Set plate 10: Liquid level detection device
11: Fuel pump unit 12: Float 14: Arm member 15: Detection unit 16: Magnetic detection element 17: Primary molded product 18: Terminal 19a: Tip portion 19b of each terminal: Base end portion 20 of each terminal: Mold resin portion 21 : Insert 22: Seal film 23: Through hole 30: Magnet holder
31: Cover 32: Magnet
36: Flange 38: Housing member 40: Narrow part 42: Wide part 44: Groove 50: Fuel tank 52: Liquid level 60: Fuel meter 62: Indicator 64: CPU

Claims (4)

Float,
An arm member attached to the float for converting the vertical motion of the float into a rotational motion;
A detection element for detecting the rotational movement of the arm member;
A terminal having one end electrically connected to the detection element;
A resin coating portion covering a part of the terminal;
Provided in a covering portion covered with the covering portion of the terminal, and a sealing film that seals between the terminal and the covering portion, and
A through hole is provided in the covering portion of the terminal, and the seal film is also provided in the through hole.
The terminal is a plate-shaped member,
The covering portion of the terminal has a narrow portion having a small size in the width direction orthogonal to the extending direction and the thickness direction of the terminal, and a wide portion having a wide size in the width direction orthogonal to the extending direction and the thickness direction. And
The narrow portion and the wide portion are alternately arranged in the extending direction,
The liquid level detection device , wherein the through hole is provided in the wide portion and extends in the thickness direction . A storage member for storing the detection element;
The liquid level detection device according to claim 1, wherein the housing member is covered with the covering portion. The terminal extends in a direction away from the detection element from the surface of the detection element;
The liquid level detection device according to claim 1, wherein the through-hole is provided on the detection element side in the covering portion. The minimum cross-sectional area of the terminal when the terminal is cut along a plane orthogonal to the extending direction within the range in which the through hole is provided is when the terminal is cut along a plane orthogonal to the extending direction at the narrow portion The liquid level detection device according to any one of claims 1 to 3, wherein the liquid level detection device is equal to or larger than a sectional area of the terminal.

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