JP2017090127A - Liquid level detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level detection device capable of reliably starting the detection of a liquid level height by preventing a damage of a float arm and the like after installed in a fuel tank.SOLUTION: A liquid level detection device 100 is installed inside a tank through an opening 91 of a fuel tank 90 in a state of being assembled to a sub-tank 30. The liquid level detection device 100 includes: a rotor 50; a housing 40; an attachment 60; and a return mechanism. The rotor 50 includes: a float 55; and a float arm 56, and rotates according to the height of the liquid level. The housing 40 rotatably supports the rotor 50. The attachment 60 support the housing 40 to the sub-tank 30, while allowing a displacement to two directions mutually opposed from a reference position, and displaces the housing 40 by inputting a load to the rotor 50. The return mechanism returns the housing 40 to the reference position when a load inputted to the rotor 50 is off-loaded.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a liquid level detection device that detects a liquid level height of a liquid stored in a container.

  Conventionally, as disclosed in, for example, Patent Document 1 and Patent Document 2, a liquid level detection device having a float and a float arm is known. Such a liquid level detection device is inserted into an opening provided in the fuel tank in a state of being assembled in a configuration such as an upper holder and a sub tank, and is disposed in the fuel tank.

JP 2012-181106 A JP-A-6-160156

  In the configuration disclosed in Patent Document 1, in the step of disposing the liquid level detection device in the fuel tank together with the sub-tank or the like, the float and the float arm having the protruding shape are arranged around the opening of the fuel tank and other fuel tanks. It becomes easy to contact built-in items. As a result, the float arm and the like were easily damaged and dropped due to contact with the periphery of the opening. In order to solve such problems, the inventor considered that it is effective to adopt a support structure that allows the displacement of the liquid level detection device with respect to the sub-tank to exhibit a buffering action.

  Here, Patent Document 2 discloses a support structure in which a lower holder that rotatably supports a float arm is supported with respect to the upper holder in a state where rotation about a boss portion is allowed. With such a support structure, the lower holder rotates in one specific direction by contact of the bottom reference rod with the bottom surface of the fuel tank, and the height of the lowest position of the float with respect to the bottom surface is kept constant. As described above, although the purpose is different, the lower holder of Patent Document 2 is also supported by the upper holder while being allowed to rotate.

  However, in the support structure of Patent Document 2, the lower holder is allowed to be displaced only in one specific direction in which the bottom reference rod is pushed up to compress the torsion coil spring. Therefore, even if the support structure of Patent Document 2 is adopted, it is difficult to exhibit the buffering action depending on the input direction of the load caused by the contact. As a result, damage such as a float arm could still occur.

  The present disclosure has been made in view of such problems, and the purpose thereof is to prevent damage to the float arm and the like, and can reliably start detection of the liquid level after being placed in the container. The object is to provide a liquid level detection device.

  In order to achieve the above object, the disclosed first aspect is arranged in the container through the opening (91) provided in the container (90) in a state assembled to the assembly (30, 230), A liquid level detection device for detecting the liquid level height of the liquid stored in the container, having a float part (55) floating on the liquid level and an arm part (56) to which the float part is attached, Rotating body (50) that rotates according to the height of the rotating body, a supporting body (40) that rotatably supports the rotating body, and a support that allows displacement in two opposite directions from a specific reference position (RP). A displacement permissive mechanism (60, 260) for supporting the body with respect to the assembly and displacing the support body by inputting a load to the rotating body, and when the load inputted to the rotating body is unloaded, the supporting body And a return mechanism (70, 270) for returning to a reference position. Are that the liquid level detecting device.

  The displacement allowance mechanism in this aspect allows the displacement of the support body in two opposite directions from a specific reference position. Therefore, even when a load is input to the float arm due to contact with the periphery of the opening in the process of inserting the liquid level detection device together with the assembly into the opening and placing them in the container, the displacement permissible mechanism is The support body can be displaced in the input direction of the generated load to exert a buffering action. Further, when the load input to the rotating body is unloaded, the support body can return to the reference position by the operation of the return mechanism, and can return to the state before the displacement. According to the above, damage to the float arm or the like is prevented, and the liquid level detection device arranged in the container can reliably start detection of the liquid level.

  Note that the reference numbers in the parentheses merely show an example of a correspondence relationship with a specific configuration in an embodiment described later, and do not limit the scope of the present invention.

It is a figure which shows typically a mode that the liquid level detection apparatus by 1st embodiment was arrange | positioned in the fuel tank. It is a perspective view which shows the structure of the liquid level detection apparatus by 1st embodiment. It is a perspective view which shows the structure of a liquid level detection apparatus. It is a perspective view which shows the structure of a liquid level detection apparatus. It is a longitudinal cross-sectional view which shows the structure of a liquid level detection apparatus. It is a figure which shows the condition where the float arm contacted the opening periphery in the insertion process. It is a figure which shows the condition where the float arm contacted the opening periphery in the insertion process. It is a perspective view which shows the structure of the liquid level detection apparatus by 2nd embodiment. It is a perspective view which shows the structure of a liquid level detection apparatus. It is a perspective view which shows the structure of a liquid level detection apparatus. It is a longitudinal cross-sectional view which shows the structure of a liquid level detection apparatus. It is a rear view which shows the structure of the liquid level detection apparatus by 3rd embodiment. It is a cross-sectional view which shows the structure of a liquid level detection apparatus. It is sectional drawing which shows the structure of a spring unit. It is a figure which shows the assembly process of a return mechanism. It is a figure which shows the state which the liquid level detection apparatus rotationally displaced.

  Hereinafter, a plurality of embodiments of the present disclosure will be described based on the drawings. In addition, the overlapping description may be abbreviate | omitted by attaching | subjecting the same code | symbol to the corresponding component in each embodiment. When only a part of the configuration is described in each embodiment, the configuration of the other embodiment described above can be applied to the other part of the configuration. In addition, not only combinations of configurations explicitly described in the description of each embodiment, but also the configurations of a plurality of embodiments can be partially combined even if they are not explicitly specified unless there is a problem with the combination. .

(First embodiment)
As shown in FIG. 1, the liquid level detection device 100 according to the first embodiment is disposed in a fuel tank 90 that stores fuel as a liquid. The liquid level detection device 100 detects the liquid level height of the fuel stored in the fuel tank 90 in a state where it is assembled to the sub tank 30 as a part of the fuel pump module 10. The detection result detected by the liquid level detection device 100 is output to an in-vehicle device such as a combination meter and notified to the driver.

  The fuel pump module 10 includes a sub tank 30, a flange 23, a fuel pump 25, a liquid level detection device 100, and the like.

  The sub tank 30 is formed in a bottomed cylindrical shape by a resin material or the like. The sub tank 30 functions as a container for collecting the fuel stored in the fuel tank 90 around the fuel pump 25 and immersing the suction port of the fuel pump 25 in the fuel. The sub tank 30 has a bottom wall 31 and a peripheral wall 33. The bottom wall 31 is pressed against the bottom of the fuel tank 90 against the flange 23 by a restoring force of a spring provided between the sub tank 30 and the flange 23.

  The peripheral wall 33 is erected in a cylindrical shape so as to surround the bottom wall 31. The peripheral wall 33 forms an opening opened upward. A part of the peripheral wall 33 forms a recessed portion 34 that is partially recessed toward the inner peripheral side. The recessed portion 34 forms an accommodating portion 35 that accommodates the liquid level detecting device 100. The recessed portion 34 supports the liquid level detection device 100. The recess 34 is provided with a bearing opening 37 and a pair of projections 38 as a configuration for detachably mounting the liquid level detection device 100.

  The bearing opening 37 is a through hole that penetrates the wall portion of the recessed portion 34 in the wall thickness direction. The bearing opening 37 is formed in a perfect circle shape. The bearing opening 37 is formed at a position closer to the opening than the bottom wall 31 in the axial direction of the sub tank 30. An outer peripheral side sealing groove 37 a is provided on the inner peripheral wall surface of the bearing opening 37. The outer peripheral side sealing groove 37a is an annular groove in which a part of the inner peripheral wall surface is recessed toward the outer peripheral side. The outer peripheral side seal groove 37a extends along the circumferential direction of the inner peripheral wall surface, and goes around the inner peripheral wall surface.

  The protrusion 38 protrudes in a cylindrical shape from the inner peripheral wall surface of the recessed portion 34. The protrusion 38 is provided at a position closer to the bottom wall 31 than the bearing opening 37. Each protrusion 38 is formed on each side with a center line CL (see FIG. 3) passing through the center of the bearing opening 37 interposed therebetween. The center line CL is an imaginary line along the axial direction of the sub tank 30.

  The flange 23 is formed in a disk shape from a resin material or the like. The flange 23 serves as a lid that closes the opening 91 provided on the ceiling of the fuel tank 90 from the outside. The fuel pump module 10 is inserted into the fuel tank 90 through the opening 91. The flange 23 is provided with a connector that is connected to an external in-vehicle device.

  The fuel pump 25 is formed in a cylindrical shape as a whole. The fuel pump 25 is held with respect to the sub tank 30 in a posture in which the suction port faces downward. The fuel pump 25 rotates the impeller by an electric motor, and discharges the fuel collected in the sub tank 30 toward the internal combustion engine.

  The liquid level detection device 100 is a sensor that enables detection of the liquid level height by outputting an electrical resistance value corresponding to the liquid level height. The liquid level detection device 100 detects the liquid level height of the space outside the sub tank 30 in the storage space formed by the fuel tank 90. As shown in FIGS. 1 to 5, the liquid level detection device 100 includes a rotating body 50, a housing 40, an attachment 60, and a return mechanism 70.

  The rotating body 50 rotates relative to the housing 40 in accordance with the liquid level. The rotating body 50 includes a float 55, a float arm 56, a contact plate 51, and the like. The float 55 is made of a material having a specific gravity smaller than that of the fuel. The float 55 can float on the liquid level of the fuel. The float arm 56 is formed by bending a thin metal rod (for example, about 2 to 3 mm in diameter) made of metal such as stainless steel at a plurality of locations. One end of the float arm 56 is inserted into an insertion hole provided in the housing 40. A float 55 is attached to the other end of the float arm 56.

  The contact plate 51 is formed in a plate shape from a resin material. The contact plate 51 is rotatably attached to the housing 40. The contact plate 51 operates integrally with the float arm 56, and converts the vertical movement of the float 55 following the liquid level into movement in the rotational direction. In the contact plate 51, a metal slider is attached to the back surface of the contact plate 51 that faces a resistance substrate 42 described later. The slider slides on the exposed surface of the resistance substrate 42 by the rotation of the contact plate 51.

  The housing 40 is formed of a resin material or the like. The housing 40 is attached to the attachment 60, and is supported by the sub tank 30 via the attachment 60. The housing 40 includes a plate support shaft 41 and stoppers 43 and 44. The housing 40 holds a resistance substrate 42.

  The plate support shaft 41 protrudes in a cylindrical shape from the main body portion of the housing 40 toward the outer peripheral side of the sub tank 30. The plate support shaft 41 forms an insertion hole through which one end of the float arm 56 is inserted. The plate support shaft 41 rotatably supports the rotating body 50 including the contact plate 51. The central axis of the plate support shaft 41 becomes the virtual rotation axis AL2 of the rotating body 50 (see FIG. 5). The plate support shaft 41 defines the rotation center of the rotating body 50.

  The stoppers 43 and 44 are formed on the edge of the housing 40, respectively. The stoppers 43 and 44 protrude from the main body portion of the housing 40 along the axial direction of the plate support shaft 41. The stoppers 43 and 44 are located on the rotation path of the float arm 56. The stoppers 43 and 44 regulate the rotation of the rotating body 50 by contacting the float arm 56. The stoppers 43 and 44 define the rotation range of the rotating body 50.

  The resistance substrate 42 forms a variable resistor together with the slider. A resistance pattern is formed on the surface of the resistance substrate 42 along the rotation path of the slider. When the slider 52 is displaced along the resistance pattern, the electrical resistance value indicated by the variable resistor increases or decreases. The in-vehicle device can acquire the current liquid level height based on the electric resistance value indicated by the variable resistor.

  The attachment 60 supports the housing 40 with respect to the sub tank 30. The attachment 60 can be displaced relative to the sub tank 30 in the clockwise direction and the counterclockwise direction along the circumferential direction of the bearing opening 37 (see FIG. 4). The attachment 60 has a locking portion 65 and a main body rotation shaft 61.

  The locking portion 65 is a standing wall protruding from the main body portion of the attachment 60 toward the housing 40. The locking portion 65 holds the housing 40 against the main body portion of the attachment 60 by engaging with a locking groove provided in the housing 40.

  The main body rotation shaft 61 is a shaft portion that protrudes in a columnar shape from the main body portion of the attachment 60 in a direction opposite to the locking portion 65. The main body rotation shaft 61 is fitted in the bearing opening 37. The main body rotation shaft 61 forms a slight clearance with the bearing opening 37 in order to realize a smooth rotational displacement of the attachment 60. The central axis of the main body rotation shaft 61 becomes the virtual rotation axis AL1 of the housing 40 (see FIGS. 3 and 5). The rotation axis AL1 of the housing 40 is along the rotation axis AL2 of the rotating body 50 and is substantially parallel to the rotation axis AL2. The main body rotation shaft 61 defines the rotation center of the housing 40. The rotation center of the housing 40 is set at the center of the main body of the attachment 60, and is defined at a position shifted in the radial direction of the plate support shaft 41 with respect to the rotation center of the rotating body 50.

  An inner peripheral seal groove 62, a spring groove 63, and a screw hole 64 are formed in the main body rotation shaft 61. The inner peripheral side seal groove 62 is provided in a region of the outer peripheral wall surface of the main body rotation shaft 61 that is in contact with the inner peripheral wall surface of the bearing opening 37. The inner peripheral side seal groove 62 is opposed to the outer peripheral side seal groove 37a in the radial direction. The inner peripheral seal groove 62 is an annular groove in which a part of the outer peripheral wall surface is recessed toward the inner peripheral side. The inner peripheral side seal groove 62 extends along the circumferential direction of the outer peripheral wall surface, and goes around the outer peripheral wall surface over the entire circumference. An O-ring 66 is accommodated in an annular space formed by the inner peripheral seal groove 62 and the outer peripheral seal groove 37a. The O-ring 66 is a seal member formed in a ring shape from a rubber material or the like. The O-ring 66 is slightly crushed by the inner peripheral side seal groove 62 and the outer peripheral side seal groove 37 a, thereby liquid-tightly sealing between the outer peripheral wall surface of the main body rotation shaft 61 and the inner peripheral wall surface of the bearing opening 37. doing.

  The spring groove 63 and the screw hole 64 are formed on the top surface 61 a of the main body rotation shaft 61. The top surface 61 a of the main body rotation shaft 61 protrudes to the inner peripheral side of the recessed portion 34. The spring groove 63 is formed by partially denting the top surface 61a. The spring groove 63 is a curved groove that passes through the center of the top surface 61a, and smoothly curves downward from the center of the top surface 61a toward the outer edge. The screw hole 64 is a cylindrical hole formed at the center of the top surface 61a. The screw hole 64 is provided at the bottom of the spring groove 63. The spring groove 63 and the screw hole 64 are elements for holding the return mechanism 70.

  The return mechanism 70 is disposed inside the sub tank 30 and is located on the opposite side of the rotating body 50 with the wall portion of the recessed portion 34 interposed therebetween. The return mechanism 70 has a bar spring 71 and a mounting screw 73. The bar spring 71 is a spring member obtained by bending a round bar-shaped metal material. A central portion 71 c of the bar spring 71 is shaped to fit into the spring groove 63. The central portion 71 c is smoothly curved in accordance with the spring groove 63. In addition, the cross section of the central portion 71c is formed in a rectangular shape. A cylindrical mounting hole 72 through which the mounting screw 73 is inserted is formed in the central portion 71c. The mounting screw 73 fastens the tip portion protruding from the mounting hole 72 to the screw hole 64. The mounting screw 73 fixes the bar spring 71 in which the central portion 71 c is fitted in the spring groove 63 to the main body rotation shaft 61. The bar spring 71 assembled to the main body rotation shaft 61 prevents the main body rotation shaft 61 from falling off from the bearing opening 37.

  The bar spring 71 is arranged along the wall portion of the recessed portion 34 in a state where the bar spring 71 is curved in a U shape so as to make both end portions approach each other. Each end of the bar spring 71 is in contact with each projection 38 from the inside. The bar spring 71 applies a clockwise restoring force and a counterclockwise restoring force to the main body rotation shaft 61 by bending each section from the central portion 71c to each end. The bar spring 71 exhibits a function of pulling back the attachment 60 to a specific position (hereinafter referred to as a reference position) RP in which the opposing restoring forces in these two directions are balanced. The restoring force by the bar spring 71 also acts as a holding load HT that prevents the displacement from starting on the attachment 60 at the reference position RP. The holding load HT is a holding torque for holding the attachment 60 and the housing 40 at the reference position RP.

  Here, when the float arm 56 strongly collides with the stoppers 43 and 44, the float arm 56 is plastically deformed by the reaction force received from the stoppers 43 and 44, or rides on the stoppers 43 and 44. A load that is plastically deformed by a reaction force that the float arm 56 receives from the stoppers 43 and 44 is defined as a deformation load, and a load that the float arm 56 rides on each stopper 43 is defined as a climbing load. The holding load HT is set so that the displacement of the housing 40 is started in a state in which the load acting on the float arm 56 from the stoppers 43 and 44 is lower than both the deformation load and the riding load.

  The reference position RP in the first embodiment is an angular position in which the long side direction of the housing 40 formed in a substantially rectangular parallelepiped shape is along the axial direction of the sub tank 30 in the liquid level detection device 100 that rotates relative to the sub tank 30. (See FIG. 4). The liquid level detection apparatus 100 is assumed to detect the liquid level in a state where the two-direction restoring force applied by the return mechanism 70 is at the reference position RP in which the liquid level detection apparatus 100 is balanced.

  The attachment 60 and the return mechanism 70 described above are assembled to the sub tank 30 to allow rotational displacement of the housing 40 in two opposite directions from the reference position RP. Therefore, when a rotational force exceeding the holding load HT is generated in the attachment 60 due to the load input to the float arm 56 and the like, the attachment 60 is rotationally displaced in the load input direction together with the housing 40 and the rotating body 50. When the load that has been input to the float arm 56 or the like is unloaded, the return mechanism 70 returns the attachment 60 and the housing 40 to the reference position RP.

  Next, in the insertion step of inserting the fuel pump module 10 into the opening 91, the details of the buffering action in which the attachment 60 and the return mechanism 70 prevent the float arm 56 from being damaged will be described with reference to FIGS. This will be described with reference to FIG.

  As shown in FIG. 6, the rotating body 50 in the inserting step is rotated to an angular position where the float arm 56 is brought into contact with the stopper 43 by the action of gravity. In this state, first, the fuel pump module 10 is inserted into the opening 91 with the float 55 and the tip of the float arm 56 inserted in a posture in which the axial direction of the sub tank 30 is inclined with respect to the axial direction of the opening 91. Thereafter, the fuel pump module 10 is rotated clockwise so that the axial direction of the sub tank 30 is along the axial direction of the opening 91. At this time, the tip of the float 55 or the float arm 56 can come into contact with the periphery of the opening 91 of the fuel tank 90 from the inside.

  When contacting the periphery of the opening 91, the float arm 56 is pressed against the stopper 43 by a reaction force received from the periphery of the opening 91. When the moment around the main body rotation shaft 61 generated by the force input from the float arm 56 to the stopper 43 exceeds the holding load HT by the bar spring 71, the liquid level detection device 100 rotates counterclockwise from the reference position RP. In this way, the attachment 60 and the return mechanism 70 exhibit a buffering action that protects the float arm 56 and the like.

  When the sub tank 30 passes through the opening 91 and the load input to the float 55 or the float arm 56 is unloaded, the liquid level detection device 100 rotates clockwise and returns to the reference position RP. . By applying the holding load HT by the bar spring 71, the housing 40 and the attachment 60 can surely return to the reference position RP.

  In another situation shown in FIG. 7, the float arm 56 and the tip of the float arm 56 are in contact with the periphery of the opening 91 of the fuel tank 90 from the outside without being successfully inserted into the opening 91. In this case, due to the reaction force received from the periphery of the opening 91, the float arm 56 rotates to the angular position where it comes into contact with the stopper 44 and is pressed against the stopper 44. When the moment around the main body rotation shaft 61 generated by the force input to the stopper 44 exceeds the holding load HT by the bar spring 71, the liquid level detection device 100 rotates clockwise from the reference position RP. In this way, a buffering action for protecting the float arm 56 and the like is exhibited. Then, when the load input to the float 55 or the float arm 56 is unloaded by performing the insertion process again, the liquid level detection device 100 rotates counterclockwise and returns to the reference position RP.

  The attachment 60 of the first embodiment described so far allows the displacement of the housing 40 in two opposite directions from the specific reference position RP. Therefore, even when a load is input to the float arm 56 that contacts the periphery of the opening 91 or the like in the insertion process of the fuel pump module 10, the attachment 60 displaces the housing 40 in the input direction of the load and exhibits a buffering action. obtain. Furthermore, if the input load is unloaded, the housing 40 can return to the reference position RP by the operation of the return mechanism 70 and return to the state before displacement. According to the above, damage to the float arm 56 and the like during the insertion process is prevented, and the liquid level detection device 100 arranged in the fuel tank 90 can reliably start detecting the liquid level.

  In addition, the attachment 60 in the first embodiment rotationally displaces the housing 40 and the like with respect to the sub tank 30. With such a configuration, for example, compared to a configuration in which the housing 40 is slid with respect to the sub tank 30, the reachable range of the displaced housing 40 can be within a narrow region, specifically, within the accommodating portion 35. Therefore, even if the attachment 60 is provided, the fuel pump module 10 can maintain a compact physique that can be disposed in the fuel tank 90 through the opening 91.

  Further, as in the first embodiment, if the axial direction of the main body rotation shaft 61 is along the axial direction of the plate support shaft 41, the housing 40 extends along the wall portion of the recessed portion 34 without leaving the sub tank 30. Displaces and exhibits a buffering effect. According to the above, the reachable range of the housing 40 can be accommodated in the accommodating portion 35. Therefore, even if the attachment 60 is added, the fuel pump module 10 can maintain a compact physique that can be inserted from the opening 91.

  Furthermore, in the first embodiment, the rotation centers of the housing 40 and the rotating body 50 are shifted from each other. With such a configuration, it is possible to avoid a situation in which the main body rotation shaft 61 and the plate support shaft 41 are overlapped in the axial direction and the rotating body 50 protrudes greatly from the wall surface of the recessed portion 34. Therefore, the fuel pump module 10 can maintain a compact physique that can be inserted from the opening 91.

  In addition, if the return mechanism 70 is arranged inside the sub tank 30 as in the first embodiment, the attachment 60 and the housing 40 can be arranged close to the wall portion of the recessed portion 34. Therefore, the fuel pump module 10 can maintain a compact physique that can be inserted from the opening 91.

  Further, the return mechanism 70 of the first embodiment applies a holding load HT to the housing 40. Therefore, the return mechanism 70 causes the restoring force exceeding the frictional force of the sliding portion between the main body rotation shaft 61 and the bearing opening 37 to act on the attachment 60 and causes the housing 40 displaced from the reference position RP by the external force to move to the reference position RP. Can be reliably returned. Therefore, the liquid level detection device 100 of the fuel pump module 10 disposed in the fuel tank 90 can detect the liquid level at the regular reference position RP.

  Furthermore, the holding load HT of the first embodiment is set so that the load acting on the float arm 56 does not exceed the riding load. Therefore, before the float arm 56 rides on the stoppers 43 and 44, the attachment 60 can start the displacement of the housing 40 to exert a buffering action. Therefore, a situation in which the float arm 56 rides on the stoppers 43 and 44 and the contact plate 51 and the plate support shaft 41 are deformed or damaged is reliably avoided.

  In addition, the holding load HT of the first embodiment is set so that the load acting on the float arm 56 does not exceed the deformation load. Therefore, before the float arm 56 is plastically deformed, the attachment 60 can start the displacement of the housing 40 to exhibit a buffering action. Therefore, the situation where the float arm 56 is deformed or damaged is reliably avoided.

  In addition, as in the first embodiment, the return mechanism 70 that uses the restoring force of the bar spring 71 has a configuration of the fuel pump module 10 as compared with a mode in which the housing 40 is returned to the reference position RP using, for example, an actuator or the like. Is difficult to complicate. Moreover, if it is the structure assembled | attached to the attachment 60 in the state which curved the bar spring 71, a strong restoring force will act also on the attachment 60 in the reference | standard position RP. Therefore, if the external force is removed, the housing 40 and the attachment 60 can be reliably returned to the reference position RP.

  Furthermore, in the first embodiment, since the return mechanism 70 is disposed inside the sub tank 30, the housing 40 can be easily accommodated in the accommodating portion 35. Therefore, even if the attachment 60 and the return mechanism 70 are added to the liquid level detection device 100, the fuel pump module 10 can maintain a compact physique that can be inserted from the opening 91.

  In the first embodiment described so far, the sub tank 30 corresponds to the “assembly”, the recessed portion 34 corresponds to the “partition wall”, the housing 40 corresponds to the “support”, and the plate support shaft. 41 corresponds to the “second shaft portion”. The float 55 corresponds to the “float part”, the float arm 56 corresponds to the “arm part”, the attachment 60 corresponds to the “displacement allowance mechanism”, and the main body rotation shaft 61 corresponds to the “first shaft part”. To do. The bar spring 71 corresponds to a “spring member”, and the fuel tank 90 corresponds to a “container”.

(Second embodiment)
The liquid level detection device 200 according to the second embodiment is a modification of the first embodiment. In the liquid level detection device 200, the configurations of the attachment 260 and the return mechanism 270 are different from those of the first embodiment. In addition, the configuration of the sub tank 230 is also different from that of the first embodiment. Hereinafter, the details of the sub tank 230 and the liquid level detection device 200 in the fuel pump module according to the second embodiment will be described with reference to FIGS. In FIG. 10, the detailed shapes of the rotating body and the housing are not shown.

  The sub tank 230 is provided with a support shaft 237 and a pair of protrusions 238. The support shaft 237 and each protrusion 238 are provided on the outer peripheral wall surface of the recessed portion 234. The support shaft 237 protrudes in a cylindrical shape from the wall portion of the recessed portion 234 toward the outer peripheral side. Each protrusion 238 protrudes in a cylindrical shape along the axial direction of the support shaft 237.

  Both the attachment 260 and the return mechanism 270 of the liquid level detection device 200 are provided outside the recessed portion 234. The attachment 260 is provided with a main body bearing portion 261, a spring groove 263, and a screw hole 264.

  The main body bearing portion 261 is formed in a cylindrical hole shape on the back surface of the main body portion of the attachment 260. The inner diameter of the main body bearing portion 261 is slightly larger than the outer shape of the support shaft 237. The attachment 260 is fastened to the sub tank 230 by a mounting screw 267 in a state where the main body bearing portion 261 is externally fitted to the support shaft 237. Thereby, the attachment 260 is supported by the sub tank 230 so as to be capable of rotational displacement. The central axis of the main body bearing portion 261 and the support shaft 237 is a virtual rotation axis AL1 of the housing 40 (see FIGS. 8 and 11).

  The spring groove 263 and the screw hole 264 are formed on the back surface of the main body portion of the attachment 260. The spring groove 263 and the screw hole 264 are located above the main body bearing portion 261 in the back surface of the main body portion. The spring groove 263 is a curved groove that is smoothly curved toward the lower side where each protrusion 238 is disposed. The screw hole 264 is a cylindrical hole provided at the bottom of the spring groove 263.

  The return mechanism 270 includes a bar spring 271 and a mounting screw 273 that are substantially the same as the bar spring 71 and the mounting screw 73 (see FIG. 4 respectively) of the first embodiment. A central portion 271 c of the bar spring 271 is curved in an arc shape and is fitted in the spring groove 263. The central portion 271 c is fixed to the spring groove 263 by a mounting screw 273. A cylindrical mounting hole 272 through which the mounting screw 273 is inserted is formed in the central portion 271c. The mounting screw 273 is inserted into the mounting hole 272 and screwed into the main body of the attachment 260. The mounting screw 273 fastens the bar spring 271 to the attachment 260. Also in the second embodiment, the restoring force of the bar spring 271 acts as a holding load HT on the attachment 260 at the specific reference position RP.

  Even in the second embodiment described so far, the same effects as in the first embodiment can be obtained, and the attachment 260 can exert a buffering effect by displacing the housing 40 in the input direction of the load to the float arm 56. . In addition, according to the unloading of the load, the housing 40 returns to the reference position RP. Therefore, damage to the float arm 56 and the like during the insertion process is prevented, and the liquid level detection device 200 disposed in the fuel tank 90 (see FIG. 1) can reliably start detection of the liquid level.

  In addition, the return mechanism 270 of the second embodiment is disposed outside the sub tank 230 together with the attachment 260. Therefore, it is not necessary to provide an opening in the wall portion of the recessed portion 234, and a sealing member such as an O-ring 66 (see FIG. 5) is not necessary. Therefore, the configuration related to the liquid level detection device 200 can be further simplified.

  In the second embodiment described so far, the sub tank 230 corresponds to the “assembly”, the support shaft 237 corresponds to the “first shaft portion”, and the recessed portion 234 corresponds to the “partition wall portion”. The attachment 260 corresponds to a “displacement allowing mechanism”, and the bar spring 271 corresponds to a “spring member”.

(Third embodiment)
The liquid level detection device 300 according to the third embodiment is another modification of the first embodiment. In the third embodiment, as shown in FIGS. 12 and 13, the configuration of the return mechanism 370 is different from that of the first embodiment. The return mechanism 370 includes an arm member 371 attached to the attachment 60 and a pair of spring units 372 attached to the sub tank 30.

  The arm member 371 is formed in a symmetrical shape with respect to the center line CL. The arm member 371 is provided with a mounting portion 371a and a bent arm portion 371b. The attachment portion 371a is formed in a circular plate shape. The diameter of the attachment portion 371 a is defined to be approximately the same as or slightly larger than the diameter of the main body rotation shaft 61. In the center of the mounting portion 371a, a perfect circular mounting opening 371c through which the mounting screw 373 is inserted is formed. The attachment portion 371a is fixed to the top surface 61a of the main body rotation shaft 61 by fastening of an attachment screw 373 inserted through the attachment opening 371c.

  Each bent arm portion 371b is provided with a straight portion 371d and a curved portion 371e. Each straight portion 371d extends from the mounting portion 371a to the left and right along the horizontal direction. Each curved portion 371e is further extended downward from the front end in the extending direction of each straight portion 371d. Each curved portion 371e is curved in a convex shape toward the outside where the spring unit 372 is located so as to come into contact with the spring unit 372, respectively. Each bending portion 371 e slides relative to the spring unit 372 due to the rotational displacement of the arm member 371.

  As shown in FIGS. 12 to 14, the pair of spring units 372 are provided separately from the arm member 371. Each spring unit 372 is arranged on each side of the arm member 371. Each spring unit 372 is located below the center of the attachment portion 371a and faces each other. The vertical positions of the spring units 372 are aligned with each other. Each spring unit 372 includes a spring housing 372a, a coil spring 372b, a contact portion 372c, an adjuster 372d, and the like.

  The spring housing 372a is formed in a quadrangular prism shape. The spring housing 372a is fixed to the wall portion of the recessed portion 34 in a posture in which the axial direction is along the horizontal direction. A through hole is formed in the spring housing 372a along the axial direction. The accommodation space formed by the through hole has a substantially cylindrical shape. In the accommodation space, the coil spring 372b is accommodated while being compressed in the axial direction. The coil spring 372 b is a spring member in which a metal is formed in a spiral shape, and causes a restoring force to act on the arm member 371.

  The contact portion 372c is attached to an end portion located on the inner side among both end portions of the coil spring 372b. The contact portion 372c is formed in a hemispherical shape and is pressed against the outer edge of the curved portion 371e by a coil spring 372b. The contact portion 372c applies an urging force from the coil spring 372b to the arm member 371.

  The adjuster 372d is a columnar member that closes the opening located outside of the two openings formed in the spring housing 372a. The adjuster 372d holds the outer end of the coil spring 372b. A male screw portion is formed on the outer peripheral surface of the adjuster 372d, and is screwed with a female screw portion formed on the inner peripheral surface of the spring housing 372a. According to the step of rotating the adjuster 372d in the circumferential direction within the spring housing 372a, the position of the adjuster 372d in the axial direction is adjusted. As a result, the force applied from the spring unit 372 to the arm member 371 can be adjusted by increasing or decreasing the amount of contraction of the coil spring 372b.

  As shown in FIG. 15, when assembling the return mechanism 370, the arm member 371 is pushed between a pair of spring units 372. Accordingly, the arm member 371 is disposed between the pair of spring units 372 while expanding the contact portion 372c, and is fixed to the top surface 61a of the main body rotation shaft 61 that has passed through the bearing opening 37.

  As shown in FIG. 16, the liquid level detection device 300 assembled to the sub tank 30 as described above can be rotationally displaced about the rotation axis AL1 (see FIG. 13). Therefore, when a load is applied to the float arm 56 (see FIGS. 6 and 7), a buffering action is exhibited by the rotational displacement of the attachment 60 and the housing 40. Then, when the arm member 371 rotates together with the attachment 60, the urging force that acts on the curved portions 371e from the left and right spring units 372 becomes uneven. As a result, the attachment 60 and the housing 40 are pulled back to the reference position RP where the urging force of each spring unit 372 balances between the left and right by being rotated by the arm member 371.

  As in the third embodiment described so far, even if the spring unit 372 is provided separately from the arm member 371 and is held by the sub tank 30, the same buffering effect as that of the first embodiment is exhibited. Is done. Further, according to the urging force by the pair of spring units 372, the housing 40 and the attachment 60 can surely return to the reference position RP. Therefore, also in the third embodiment, damage to the float arm 56 and the like during the insertion process is prevented, and the liquid level detection device 300 can reliably start detection of the liquid level.

  In addition, in the third embodiment, the holding load HL applied to the arm member 371 at the reference position RP from the left and right can be adjusted by each adjuster 372d. Therefore, the return mechanism 370 can set an optimum holding load HL that can achieve both the prevention of damage to the float arm 56 and the like and the reliable return to the reference position RP. In the third embodiment described so far, the coil spring 372b corresponds to a “spring member”.

(Other embodiments)
Although a plurality of embodiments have been described above, the present disclosure is not construed as being limited to the above-described embodiments, and can be applied to various embodiments and combinations without departing from the scope of the present disclosure. it can.

  In the first modification of the first embodiment, a motor is provided in place of the bar spring as a configuration for returning the position of the housing and the attachment to the reference position. The motor can rotate the output shaft by utilizing a part of the electric power supplied to drive the fuel pump. The rotation of the output shaft of the motor is transmitted to the main body rotation shaft of the attachment via a gear for deceleration. The motor can return the angular position of the attachment and the housing to the reference position by appropriately rotating the output shaft. As described above, the return to the reference position may be realized by a configuration or mechanism different from the spring member.

  In the above-described embodiment, the attachment is a mechanism that allows only rotational displacement along the wall surface of the recessed portion by defining a rotational axis AL1 parallel to the rotational axis AL2 of the rotating body. However, the rotation axis of the attachment may be defined in the vertical direction along the axial direction of the sub tank, or may be defined in the horizontal direction along the liquid level, for example.

  Further, the attachment may be a mechanism that allows sliding displacement in two opposite directions along the vertical direction or the horizontal direction. Furthermore, the attachment may be a mechanism that allows both sliding displacement and rotational displacement.

  In the above embodiment, the main body rotation shaft of the attachment and the plate support shaft of the housing are shifted from each other along the wall surface of the recessed portion. However, if the thickness of the liquid level detection device is allowed, the main body rotation shaft and the plate support shaft may be arranged side by side in the axial direction.

  Each spring member of the above embodiment applies a holding load due to a set load to an attachment or the like at a reference position. However, as long as reliable return to the reference position can be realized, the return mechanism may be configured not to apply a holding load. For example, if the configuration uses a coil spring that is compressed in the circumferential direction to apply a restoring force, the holding load can be eliminated. Moreover, although the return mechanism of the said embodiment applied the load to the attachment, the structure which applies a load to a housing may be sufficient.

  The holding load in the above embodiment is set so that the force acting on the float arm from the stopper does not exceed the riding load and the deformation load. Such climbing load and deformation load differ depending on the specifications of the liquid level detection device depending on the thinness of the float arm, the protruding amount of each stopper, the rigidity and strength of the plate support shaft, and the like. Therefore, it is desirable that the holding load is appropriately set so as not to exceed both the riding load and the deformation load assumed in the liquid level detection device. According to such a setting, a situation such as dropping of the rotating body is surely prevented.

  In the liquid level detection device of the above embodiment, the angular position of the rotating body is detected by a variable resistor. However, the liquid level detection device may be configured to detect the angular position of the rotating body using a magnet and a magnetoelectric conversion element. Further, the resistance substrate constituting the variable resistor may be held in a rotating configuration such as a contact plate instead of the housing.

  The liquid level detection device of the above embodiment is inserted into the opening of the fuel tank in a state where it is assembled to the sub tank of the fuel pump module. However, the configuration in which the liquid level detection device is assembled is not limited to the sub tank. For example, the liquid level detection device may be inserted into the opening of the fuel tank in a state assembled to a bracket or the like formed of a metal plate material.

  In the above, the example which applied this invention to the liquid level detection apparatus which detects the residual amount of a fuel was demonstrated. However, the application target of the present invention is not limited to the liquid level detection device that measures the remaining amount of fuel, but is provided in a container for other liquids mounted on the vehicle, such as brake fluid, engine coolant, and engine oil. It may be a liquid level detection device. Furthermore, the present invention is applicable not only to vehicles but also to liquid level detection devices provided in liquid containers provided in various consumer devices and various transport machines.

HT, HL Holding load, RP reference position, 30, 230 Sub tank (assembled body), 34, 234 Recessed part (partition wall part), 237 Support shaft (first shaft part), 40 Housing (support body), 41 Plate support Shaft (second shaft portion), 43, 44 Stopper, 50 Rotating body, 55 Float (float portion), 56 Float arm (arm portion), 60, 260 Attachment (displacement allowance mechanism), 61 Main body rotation shaft (first shaft) Part), 70,270 return mechanism, 71,271 bar spring (spring member), 372b coil spring (spring member), 90 fuel tank (container), 91 opening, 100, 200, 300 Liquid level detection device

Claims (11)

The liquid level height of the liquid which is arrange | positioned in the said container through the opening (91) provided in the container (90) in the state assembled | attached to the assembly | attachment body (30,230), and is stored by this container is detected. A liquid level detection device,
A rotating body (50) having a float part (55) floating on the liquid level and an arm part (56) to which the float part is attached, and rotating according to the height of the liquid level;
A support (40) for rotatably supporting the rotating body;
Displacement allowance for supporting the support relative to the assembly while allowing displacement in two opposite directions from a specific reference position (RP), and displacing the support by input of a load to the rotating body Mechanism (60, 260);
A liquid level detection apparatus comprising: a return mechanism (70, 270) for returning the support to the reference position when the load input to the rotating body is unloaded.   The liquid level detection device according to claim 1, wherein the displacement allowance mechanism rotationally displaces the support relative to the assembly by input of a load to the rotating body.   The axial direction of the first shaft portion (61, 237) defining the rotation center of the support body is along the axial direction of the second shaft portion (41) defining the rotation center of the rotation body. The liquid level detection apparatus described.   The liquid level detection device according to claim 3, wherein the rotation center of the support body is defined at a position shifted in a radial direction of the second shaft portion with respect to the rotation center of the rotation body. The assembly is provided with partition walls (34, 234) for supporting the support,
The liquid level detection device according to claim 1, wherein the return mechanism is disposed on the opposite side of the rotating body with the partition wall interposed therebetween.   The liquid level detection apparatus according to any one of claims 1 to 5, wherein the return mechanism generates a holding load (HT, HL) that hinders the start of displacement of the support at the reference position.   The liquid level detection device according to claim 6, wherein the support has a stopper (43, 44) that defines a rotation range of the rotating body by contact with the arm portion. When the load that the arm portion in contact with the stopper rides on the stopper is a riding load,
The liquid level detection device according to claim 7, wherein the holding load is set so that displacement of the support is started in a state where a load acting on the arm portion from the stopper is lower than the climbing load. . When the load that plastically deforms due to the reaction force received from the stopper by the arm portion in contact with the stopper is a deformation load,
The liquid level detection according to claim 7 or 8, wherein the holding load is set so that displacement of the support is started in a state where a load acting on the arm portion from the stopper is lower than the deformation load. apparatus.   10. The liquid level detection device according to claim 1, wherein the return mechanism returns the support to the reference position by a restoring force of a spring member (71, 271, 372 b).   The liquid level detection device according to claim 10, wherein the spring member applies a restoring force to the support body at the reference position.

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