JP6100140B2 - Liquid level detector - Google Patents

Description

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

  Patent Document 1 discloses a liquid level detection structure. The liquid level detecting mechanism includes an arm rotatably supported, a float attached to one end of the arm, and a balance weight attached to the other end of the arm.

JP-A-10-253426

  The arm converts the float that moves in the vertical direction as the liquid level fluctuates in the vertical direction into a rotational motion. For this reason, the arm is rotatably arranged at an angle at which the float can move in the vertical direction according to the fluctuation in the vertical direction of the liquid level. On the other hand, when the arm's rotatable angle increases, parts arranged around the arm and the float must be arranged away from the arm and the float so that the parts do not come into contact with the arm and the float. There is a possibility of becoming. In this specification, the technique which regulates the rotation angle of an arm member is provided.

  The liquid amount detection device disclosed in this specification includes a float, an arm member, and a weight member. The arm member is attached to the float, and converts the vertical motion of the float into a rotational motion. The weight member is attached to the arm member located on the opposite side of the float with respect to the rotation center of the arm member. The weight member has a restricting portion that restricts the rotation of the arm member.

  In the above liquid amount detection device, the weight member has a restricting portion that restricts the rotation of the arm member. Therefore, the rotation of the arm member can be restricted without arranging a dedicated member that restricts the rotation of the arm member. According to this configuration, it is possible to regulate the rotation angle of the arm member while suppressing the complicated structure of the liquid amount detection device.

  The fuel supply device disclosed in the present specification includes a fuel pump unit including a fuel pump that pumps fuel in a fuel tank, and the liquid amount detection device described above. The arm member is attached to the fuel pump unit.

  According to this configuration, since the rotation angle of the arm member can be restricted while suppressing the complexity of the structure of the liquid amount detection device, it is possible to suppress the complexity of the structure of the fuel pump unit. it can. As a result, as compared with the configuration in which the rotatable angle of the arm member is not restricted, the restriction on the position of the parts such as the fuel pump unit is relaxed.

The structure of a fuel supply system is shown. The II-II cross section of FIG. 1 is shown. The longitudinal section of a magnetic sensor unit is shown.

  First, the features of the embodiments described below are listed. Note that the features listed here are all independently effective.

(Feature 1) The liquid amount detection device may further include a magnetic sensor that outputs an analog signal corresponding to the rotational movement of the arm member. According to this configuration, the rotational movement of the arm member can be detected by the magnetic sensor. As a result, the amount of liquid can be detected using the detection result of the magnetic sensor.

(Feature 2) In the liquid amount detection device, the arm member includes a weight mounting portion extending from the weight member to the float side beyond the rotation center of the arm member, and a float mounting portion extending from the tip of the weight mounting portion to the float. You may have. The float attachment portion and the weight attachment portion may be made of different members. According to this configuration, the float attachment portion and the weight attachment portion can be made of different materials.

(Feature 3) The weight mounting portion may be made of a material having a density lower than that of the float mounting portion. According to this configuration, the arm member can be made relatively light. As a result, the buoyancy that the float receives can be reduced.

  As shown in FIG. 1, the fuel supply system 1 is a system for supplying fuel in a fuel tank 4 mounted on an automobile to an internal combustion engine (not shown). The fuel supply system 1 includes a fuel meter 60 and a fuel supply device 10. The fuel meter 60 is used for a display device of an automobile not shown. The fuel supply device 10 is disposed in the fuel tank 4. The fuel meter 60 and the fuel supply device 10 are electrically connected by a plurality of lines 52, 54, and 56.

  The fuel supply device 10 includes a fuel pump unit 12 and a fuel amount detection device 20. The fuel pump unit 12 is accommodated in the fuel tank 4. The fuel pump unit 12 is attached to a set plate 6 that closes the opening of the fuel tank 4. The fuel pump unit 12 includes a fuel pump (not shown). The fuel pump sucks the fuel in the fuel tank 4 into the fuel pump, boosts the pressure, and discharges the fuel outside the fuel pump. The fuel discharged from the fuel pump is supplied from the discharge port 14 to an internal combustion engine (not shown).

  The fuel amount detection device 20 includes a float 22, an arm member 24 fixed to the float 22, and a magnetic sensor unit 30 that detects the rotation angle of the arm member 24. The float 22 floats on the fuel in the fuel tank 4 and moves in the vertical direction according to the fuel level. The float 22 is rotatably attached to the tip of the arm member 24. The base end of the arm member 24 is rotatably supported with respect to the magnetic sensor unit 30. Therefore, when the float 22 moves up and down in accordance with the fuel level in the fuel tank 4, the arm member 24 swings and rotates with respect to the fuel pump unit 12.

  The arm member 24 includes a float attachment portion 24a and a base portion 24b. The float attachment portion 24a is made of a metal having resistance to a fuel such as stainless steel. The float attachment portion 24a is produced by bending a cylindrical rod-shaped member at an intermediate position. The float 22 is attached to the tip of the float attachment portion 24a. A base portion 24b is fixed to the base end of the float mounting portion 24a.

  The base portion 24b is made of a resin having resistance to fuel (for example, PPS (that is, polyphenylene sulfide resin)). The base portion 24b is made of a material different from that of the float attachment portion 24a. Specifically, the base portion 24b is made of a light material, that is, a material having a lower density (mass per unit volume) than the float mounting portion 24a. Further, the float attachment portion 24a is made of a material having higher rigidity than the base portion 24b.

    The base portion 24b is formed in a flat plate shape. As shown in FIG. 2, an engaging portion 24d for engaging and fixing the float mounting portion 24a is disposed at the distal end portion (lower end portion of FIG. 2) of the base portion 24b. In FIG. 2, a part of the float attachment portion 24a is omitted. The base portion 24b is rotatably supported by the magnetic sensor unit 30 at a fulcrum portion 24c on the tip side of the base end.

  The fulcrum part 24c has a disk shape. The rotation center X of the arm member 24 coincides with the center of the fulcrum part 24c. As shown in FIG. 2, the magnet 26 is accommodated in the fulcrum part 24c. The magnet 26 is disposed in the base portion 24b by insert molding when the base portion 24b is formed, for example. The magnet 26 is a permanent magnet. The magnet 26 has a disk shape. The center of the magnet 26 coincides with the center of the fulcrum part 24c (ie, the rotation center X). The magnet 26 has an N pole in one semicircular portion and an S pole in the other semicircular portion. The magnet 26 rotates according to the swinging rotation of the arm member 24. As a result, the direction of the magnetic field generated by the magnet 26 varies according to the swinging rotation of the arm member 24.

  A weight 28 is fixed to the base end of the base portion 24b. The weight 28 is attached to the opposite side of the arm member 24 with respect to the float 22 with the rotation center X interposed therebetween. For this reason, the weight 28 functions as a counterweight for applying an upward force to the float 22. As a result, even if the buoyancy of the float 22 is small, the float 22 floats on the fuel level.

  The weight 28 protrudes from the base portion 24b toward the fuel pump unit 12 side. The weight 28 is disposed at a position where it can abut on the protrusions 16 and 18 projecting from the fuel pump unit 12 to the side where the fuel amount detection device 20 is disposed. The protrusions 16 and 18 may be made of the same material as the casing that covers the fuel pump of the fuel pump unit 12, for example, a resin, or may be made of a different material, for example, a metal material. The protrusions 16 and 18 may be formed integrally with the casing of the fuel pump unit 12 or may be formed separately. Specifically, when the arm member 24 rotates clockwise in FIG. 1, the rotation of the arm member 24 is restricted by the weight 28 coming into contact with the protrusion 18. Further, when the arm member 24 rotates counterclockwise in FIG. 1, the rotation of the arm member 24 is restricted by the weight 28 coming into contact with the protrusion 16. That is, the weight 28 functions as a restricting portion that restricts the swinging rotation of the arm member 24.

  The magnetic sensor unit 30 supports the arm member 24 rotatably. FIG. 3 is a cross-sectional view showing the cross section of the magnetic sensor unit 30 in the vertical direction passing through the rotation center X of FIG. As shown in FIG. 3, the magnetic sensor unit 30 includes a casing 32 and a magnetic sensor 40. The casing 32 is produced by molding a resin into a plurality of layers. The casing 32 has a receiving portion 34 that receives a portion of the fulcrum portion 24 c of the arm member 24 in which the magnet 26 is accommodated. The receiving part 34 has a cylindrical shape. A magnet 26 is disposed in the hollow portion of the receiving portion 34. The casing 32 rotates the arm member 24 when the fulcrum portion 24c of the arm member 24 is slidably engaged with the flange 36 of the receiving portion 34 in a state where the magnet 26 is disposed in the receiving portion 34. Supports freely.

  The casing 32 covers the magnetic sensor 40. The magnetic sensor 40 detects the rotational motion of the arm member 24 and outputs an analog signal corresponding to the amount of fuel stored in the fuel tank 4 to the fuel meter 60 based on the detection result (see FIG. 1). The magnetic sensor 40 is a magnetic sensor that detects the rotation angle of the arm member 24. For example, a known sensor using a Hall IC can be used. Specifically, the magnetic sensor 40 includes a Hall element 42 that detects the direction of the magnetic field of the magnet 26, and a capacitor 44 that is connected to the Hall element 42. The hall element 42 and the capacitor 44 are covered with a resin cover 46 of the casing 32.

  The magnetic sensor 40 is connected to the fuel meter 60 via a power supply line 52, an output line 54 and a ground line 56. The power supply line 52, the output line 54, and the ground line 56 pass through the set plate 6 and are connected to the fuel meter 60.

  The fuel meter 60 has a CPU 64 and a display 62. The CPU 64 supplies power to the fuel amount detection device 20, specifically the magnetic sensor 40, via the power supply line 52. An analog signal output from the magnetic sensor 40 is input to the CPU 64 via the output line 54. The CPU 64 specifies the amount of fuel stored in the fuel tank 4 using the analog signal input from the magnetic sensor 40, and displays the specified amount of fuel on the display 62. The CPU 64 and the display device 62 can be configured in the same manner as in a conventionally known fuel meter. In the CPU 64, the ground line 56 is grounded.

(Liquid volume detection method)
Next, the liquid amount detection method will be described. The CPU 64 supplies power to the magnetic sensor 40 during driving of the automobile. The magnetic sensor 40 outputs an analog signal corresponding to the direction of the magnetic field of the magnet 26. When the level of the fuel level in the fuel tank 4 changes, the float 22 moves in the vertical direction, and the arm member 24 rotates as the float 22 moves in the vertical direction. The magnet 26 rotates as the arm member 24 rotates. As a result, the direction of the magnetic field of the magnet 26 varies according to the rotation of the arm member 24, that is, the height of the liquid level of the fuel in the fuel tank 4. For this reason, the analog signal output from the magnetic sensor 40 correlates with the level of the fuel level in the fuel tank 4.

  When the analog signal output from the magnetic sensor 40 is input, the CPU 64 specifies the amount of fuel stored in the fuel tank 4 and displays the specified fuel amount on the display 50. Specifically, the CPU 64 specifies the fuel amount using a database or a function indicating the relationship between the analog signal output from the magnetic sensor 40 stored in the CPU 64 and the fuel amount. The database or function is specified in advance by executing an experiment or simulation and stored in the CPU 64.

(Effect of this embodiment)
In the fuel amount detection device 20 described above, the weight 28 functions as a counterweight with respect to the float 22 and also functions as a restricting portion that restricts the swinging rotation of the arm member 24. For this reason, it is not necessary to arrange | position a counterweight and a control part separately. According to this configuration, the rotation angle of the arm member 24 can be regulated while suppressing the structure of the fuel amount detection device 20 from becoming complicated. As a result, complication of the structure of the fuel supply device 10 can be suppressed. In addition, by appropriately regulating the swinging rotation of the arm member 24, it is possible to prevent the degree of freedom of arrangement of components such as the fuel supply device 10 from being suppressed.

  In the fuel amount detection device 20 described above, the arm member 24 is made of the float attachment portion 24a and the base portion 24b which are separate members. For this reason, the arm member 24 can be made of a plurality of materials.

  The base portion 24b is made of a lighter material, that is, a material having a lower density (mass per unit volume) than the float mounting portion 24a, while the float mounting portion 24a is compared with the base portion 24b. Thus, it is made of a material having high rigidity. According to this configuration, the lightweight arm member 24 can be produced while maintaining the rigidity required for the arm member 24. As a result, it is possible to prevent the detection error from occurring due to the deformation of the arm member 24. Moreover, when the arm member 24 becomes light, the buoyancy that should act on the float 22 can be reduced. That is, for example, the float 22 can be reduced in size as compared with the case where the entire arm member 24 is made of a relatively high density material such as SUS. When the float 22 is downsized, the float 22 is less likely to contact the bottom of the fuel tank 4 even when the remaining amount of fuel is reduced. As a result, the fuel amount detection device 20 can be used to appropriately detect the amount of fuel with a small remaining amount (that is, fuel near the bottom of the fuel tank 4).

  The technical elements described in this specification or the 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.

  For example, the sensor disposed in the fuel amount detection device 20 is not limited to the magnetic sensor 40. For example, the fuel amount detection device 20 may include a resistance type (contact type) sensor whose resistance value varies according to the movement of the float 22 in the vertical direction.

  Further, for example, the “liquid amount detection device” of the present specification detects not only the fuel amount detection device 20 that detects the fuel amount in the fuel tank 4 but also the liquid in the container, for example, the amount of water stored in the water storage tank. It may be a device that performs.

  In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

1: fuel supply system, 4: fuel tank, 6: set plate, 10: fuel supply device, 12: fuel pump unit, 16, 18: protrusion, 20: fuel amount detection device, 22: float 24: arm member, 24a: Float mounting part, 24b: Base part, 24c: Support point part, 26: Magnet, 28: Weight, 30: Magnetic sensor unit, 40: Magnetic sensor, 42: Hall element

Claims (5)

Float,
An arm member attached to the float for converting the vertical movement of the float into a rotational movement;
A weight member attached to the arm member located on the opposite side of the float with respect to the rotation center of the arm member,
The weight member protrudes from the arm member,
A liquid amount detection device in which the rotation of the arm member is regulated by the weight member moving with the rotation of the arm member and coming into contact with a member disposed at a position where the weight member can contact the weight member .   The liquid amount detection device according to claim 1, further comprising a magnetic sensor that outputs an analog signal according to the rotational movement of the arm member. The arm member includes a weight mounting portion extending from the weight member to the float side beyond the rotation center of the arm member, and a float mounting portion extending from the tip of the weight mounting portion to the float.
The liquid amount detection device according to claim 1, wherein the weight attachment portion and the float attachment portion are made of different members.   The liquid amount detection device according to claim 3, wherein the weight attaching portion is made of a material having a density lower than that of the float attaching portion. A fuel pump unit comprising a fuel pump for pumping the fuel in the fuel tank;
A liquid amount detection device according to any one of claims 1 to 4,
The fuel supply device, wherein the arm member is rotatably attached to the fuel pump unit.

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