Liquid level detection device

Abstract

The liquid level detection device (1) comprises: a frame (3); a floating arm (5); a retaining frame (7) rotatably supported on the frame (3); a floating arm setting portion (11) configured such that when the floating arm (5) is set on the retaining frame (7), the first portion is elastically deformed and when the setting is completed, the first portion is restored, thereby setting the floating arm (5); a float (9) provided on the floating arm (5); and an elastic deformation preventing portion (13) preventing the elastic deformation of the first portion of the floating arm setting portion (11).

Description

Technical Field

[0001] The invention relates to a liquid level detection device. Background Art

[0002] Conventionally, there is known a fuel level sensor (level detection device) including a frame with a built-in Hall IC, a retaining frame with a built-in magnet and rotatably supported on the frame, a floating arm, and a float (see Japanese Patent Application Publication No. 2018-205137).

[0003] In a conventional liquid level detection device, a base end portion of a float arm is provided on a float arm installation portion of a holder, a tip end portion of the float arm extends from the holder, and a float is provided on the tip end portion of the float arm.

[0004] Furthermore, the conventional liquid level detection device detects the liquid level (height of the liquid surface) of the fuel by rotating the holder relative to the frame using the buoyancy that the float receives from the fuel.

[0005] In addition, in the conventional liquid level detection device, the float arm is installed on the holder by a snap-fit ​​method. That is, when the float arm is installed on the holder, a part of the float arm installation part is elastically deformed. Also, when the float arm is installed on the holder, a part of the float arm installation part is restored, thereby installing the float arm on the holder. Summary of the invention

[0006] Technical problem that the invention aims to solve

[0007] Incidentally, in the conventional liquid level detection device, in a normal use state of detecting the fuel liquid level, the float arm does not fall off from the retainer.

[0008] However, when a conventional liquid level detection device is installed on a fuel tank, an unexpected force may be applied to the float arm installation portion in an abnormal situation such as when the float arm or the float collides with the fuel tank.

[0009] In such an abnormal state, a part of the floating arm setting part is deformed, and the floating arm may fall off from the floating arm setting part. In order to prevent the floating arm from falling off from the floating arm setting part, it is considered to increase the strength of the floating arm setting part, or add a component for preventing the deformation of the floating arm setting part.

[0010] However, if the strength of the float arm installation portion is increased, the liquid level detection device becomes larger, or the assembly of the float arm to the holder is deteriorated due to an increase in insertion load, etc. In addition, if a component for preventing deformation of the float arm installation portion is added, the number of components constituting the liquid level detection device increases.

[0011] An object of the present invention is to provide a liquid level detection device that can prevent enlargement of the device, deterioration of assembly of a float arm to a holder, and increase in the number of device components, and can improve the holding strength of the float arm by the holder.

[0012] Technical solutions to the problem

[0013] The liquid level detection device involved in the present invention comprises: a frame; a floating arm; a retaining frame, which is rotatably supported on the frame; a floating arm setting part, which is set on the retaining frame, and the floating arm setting part is constructed to: set the floating arm by elastically deforming a first part when the floating arm is set on the retaining frame and restoring the first part when the floating arm has been set on the retaining frame; a float, which is set on the floating arm away from the retaining frame; and an elastic deformation preventing part, which is set on the frame and prevents elastic deformation of the first part of the floating arm setting part.

[0014] The elastic deformation preventing portion may be configured to prevent elastic deformation of the first portion of the floating arm installation portion when a rotation angle of the holder relative to the frame is within a predetermined rotation angle range.

[0015] The predetermined rotation angle range may be a rotation angle range other than a rotation angle range when the float arm is provided on the holder.

[0016] Effects of the Invention

[0017] According to the above configuration, it is possible to provide a liquid level detection device that can prevent an increase in size of the device, deterioration in assembly performance of the float arm to the holder, and an increase in the number of device components, and can improve the holding strength of the float arm by the holder. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a perspective view of the liquid level detection device according to the embodiment.

[0019] Figure 2 It is an exploded perspective view of the liquid level detection device according to the embodiment.

[0020] Figure 3 yes Figure 1 An enlarged view of part III in FIG.

[0021] Figure 4 It is a cross-sectional view of the liquid level detection device according to the embodiment.

[0022] Figure 5It is a perspective view of a frame of the liquid level detection device according to the embodiment.

[0023] Figure 6 It is a front view of the frame of the liquid level detection device involved in embodiment.

[0024] Fig. 7A The figure shows a state before the float arm is installed, and is a perspective view showing the holder and the float arm of the liquid level detection device according to the embodiment.

[0025] Figure 7B The figure shows a state in which the float arm is being installed, and is a perspective view showing the holder and the float arm of the liquid level detection device according to the embodiment.

[0026] Fig. 8A It is a bottom view for explaining the structure of the holder of the liquid level detection device according to the embodiment.

[0027] Figure 8B 1 is a side view for explaining the structure of a retainer of a liquid level detection device according to an embodiment. Fig. 8A VIIIB view in the figure).

[0028] Fig.9A It is a bottom view showing a holder to which a float arm is assembled in the liquid level detection device according to the embodiment.

[0029] Fig. 9B 1 is a side view showing a retainer to which a float arm is assembled in the liquid level detection device according to the embodiment ( Fig.9A IXB view in the figure).

[0030] Fig.10 1 is a side view showing a state in which a load acts on the float arm in a direction intersecting with the swing direction in the liquid level detection device according to the embodiment (with Fig. 9B corresponding figure).

[0031] Fig.11 It is a front view of the liquid level detection device involved in embodiment.

[0032] Fig.12 is a front view of the liquid level detection device according to the embodiment, showing the retainer from Fig.11 The state shown is a diagram in which the state is rotated clockwise by a predetermined angle.

[0033] Fig.13 yes Fig.11 View in the XIII direction.

[0034] Fig.14 yes Fig.12 View in the XIV direction. DETAILED DESCRIPTION

[0035] Various embodiments will be described below with reference to the accompanying drawings.

[0036] like Figures 1 to 4 As shown, a liquid level detection device (liquid level sensor) 1 according to the embodiment is provided in, for example, a fuel tank (not shown) of a vehicle, and detects the height position (liquid level) of the liquid surface of the fuel in the fuel tank.

[0037] The liquid level detection device 1 includes a frame (frame; housing) 3, a float arm 5, a holder (rotation member) 7, and a float 9. The holder 7 is rotatably supported (installed) on the frame 3. The holder 7 is provided with a float arm installation portion 11, and the float arm 5 is installed on the float arm installation portion 11.

[0038] When the float arm 5 is installed in the holder 7 (the float arm installation portion 11), the first portion of the float arm installation portion 11 is elastically deformed. Also, when the float arm 5 is already installed in the holder 7 (the float arm installation portion 11), the first portion of the float arm installation portion 11 (the elastically deformed portion) is restored. Thus, the holder 7 is configured such that the float arm 5 is installed in the float arm installation portion 11. The float 9 is installed at the distal end of the float arm 5 away from the holder 7.

[0039] The base end of the float arm 5 is installed at the float arm installation portion 11. When the float arm 5 is installed at the float arm installation portion 11 of the holder 7, the holder 7 and the float arm 5 are integrated. When the holder 7 rotates relative to the frame 3, the float arm 5 also rotates together with the holder 7.

[0040] When the float arm 5 is installed on the float arm installation portion 11 of the holder 7, the distal end of the float arm 5 protrudes from the holder 7. The float 9 is installed on the float arm 5 at the distal end of the distal end of the float arm 5 protruding from the holder 7.

[0041] In addition, an elastic deformation prevention portion 13 is provided on the frame 3 of the liquid level detection device 1. The elastic deformation prevention portion 13 prevents the float arm 5 provided on the holder 7 from being separated from the holder 7.

[0042] The elastic deformation preventing portion 13 prevents elastic deformation of the first portion (the elastically deformed portion) of the floating arm installation portion 11. That is, in the frame 3, the elastic deformation preventing portion 13 prevents the floating arm 5 installed in the floating arm installation portion 11 from being elastically deformed to such an extent that the floating arm 5 is separated from the floating arm installation portion 11.

[0043] In addition, when the floating arm 5 is provided on the retaining frame 7 but the retaining frame 7 is not provided on the frame 3, the elastic deformation preventing portion 13 does not perform this function. Figure 2 , Figure 5In the figure, the elastic deformation preventing portion 13 is omitted.

[0044] In the liquid level detection device 1, the buoyancy of the float 9 from the liquid (fuel) causes the holder 7 to rotate relative to the frame 3. Then, by detecting the rotation angle of the holder 7 relative to the frame 3, the liquid level is detected.

[0045] The rotation angle of the holder 7 relative to the frame 3 is detected by using, for example, a magnet (not shown) provided on the holder 7 and a Hall element (not shown) provided on the frame 3 for detecting displacement of the magnet.

[0046] The elastic deformation preventing portion 13 is configured to prevent elastic deformation of the first portion of the floating arm installation portion 11 only when the rotation angle of the holder 7 relative to the frame 3 is within a predetermined rotation angle range.

[0047] Further explanation, when the rotation angle of the retaining frame 7 (floating arm 5) is Figure 6 When the angle range indicated by the reference symbol θ1 is within the range of θ1, the elastic deformation prevention portion 13 performs this function. Figure 6 When the angle is within the range of the reference symbol θ2, the elastic deformation preventing portion 13 also performs this function.

[0048] On the other hand, when the rotation angle of the retainer 7 (floating arm 5) is Figure 6 When the angle is within the range of the reference symbol θ3, the elastic deformation preventing portion 13 does not perform this function.

[0049] in addition, Figure 6 The straight dashed lines L1, L2, L3, and L4 respectively indicate the imaginary positions of the central axes of the rod-shaped holder vicinity portion 15 of the floating arm 5 when the floating arm 5 rotates. The holder vicinity portion 15 of the floating arm 5 extends from the holder 7 in a short straight line. The dashed lines L1, L2, L3, and L4 pass through the rotational central axis C1 of the holder 7 (floating arm 5) with respect to the frame 3.

[0050] In addition, the holder 7 rotates between the one-dot chain line L1 and the one-dot chain line L4 relative to the frame 3. That is, the holder 7 rotates in the range from the one-dot chain line L1 through the one-dot chain lines L2 and L3 to the one-dot chain line L4 in the counterclockwise direction ( Figure 6 The frame 3 is rotated within a rotation angle range represented by angles θ1, θ2, and θ3. In addition, the frame 3 is not provided with elastic deformation prevention portions 13 at locations corresponding to the range represented by angle θ3.

[0051] The rotation range of the holder 7 relative to the frame 3 is limited by a pair of stoppers 19 (see Figure 1 , Figure 3) is limited. The holder 7 rotates relative to the frame 3 between the single-dot chain line L1 and the single-dot chain line L4. To further explain, the holder vicinity portion 15 of the floating arm 5 abuts against a pair of limit portions 19, respectively, so that the rotation range of the holder 7 (floating arm 5) is limited.

[0052] The predetermined rotation angle ranges θ1 and θ2 in which the elastic deformation preventing portion 13 exerts this function are rotation angle ranges other than the rotation angle range θ3 when the float arm 5 is installed in the float arm installation portion 11 installed in the holder 7 of the frame 3. The rotation angle range when the float arm 5 is installed in the float arm installation portion 11 may be, for example, a necessary minimum rotation angle range. That is, in the liquid level detection device 1, the predetermined rotation angle range in which the elastic deformation of the first portion of the float arm installation portion 11 is prevented is the rotation angle range θ1 and the rotation angle range θ2 other than the rotation angle range θ3 when the float arm 5 is installed in the holder 7.

[0053] In addition, Figure 6 In the figure, the rotation angle range θ3 is represented by an angle range of about 30°. If, for example, the minimum rotation angle range required when the floating arm 5 is set on the retaining frame 7 already set on the frame 3 is an angle range smaller than 30°, the angle range θ3 can be made smaller than Figure 6 The angle range shown is narrow. For example, the angle range θ3 may be narrowed to an angle range of about 10°. In this case, for example, at least one of the angle ranges θ1 and θ2 is expanded toward the angle range θ3.

[0054] In addition, the predetermined rotation angle at which the elastic deformation preventing portion 13 performs this function may also be within the rotation angle range when the frame 3 (liquid level detection device 1) is assembled to a tank containing a liquid (fuel) to be detected. Figure 1 In the state shown, the liquid level detection device 1 is arranged in the container. Figure 1 In the embodiment, the rotation angle of the retaining frame 7 or the floating arm 5 relative to the frame 3 becomes Figure 6 The rotation angle shown by the single-dot chain line L4, that is, Fig.11 , Fig.13 The status shown. Figure 1 In the state shown, the end of the floating arm 5 interferes with the fuel tank wall, contents, etc. and receives a reaction force. Fig.13 In FIG. 1 , only the elastic deformation preventing portion 13 is shown, and the display of the parts of the frame 3 other than the elastic deformation preventing portion 13 is omitted. Fig.14 Similarly, only the elastic deformation preventing portion 13 is shown.

[0055] Further explanation, such as Fig.13As shown in FIG. 1 , the floating arm 5 is engaged with the retaining frame 7 by snapping from the left direction, and is thus set in the floating arm setting portion 11. That is, the floating arm 5 moves to the right relative to the retaining frame 7 as shown by the arrow from the position shown by the double-dashed line, and is set in the retaining frame 7. Fig.13 In the state shown in FIG. 1 , even if the floating arm 5 moves to the right as shown by the arrow, the elastic deformation preventing portion 13 prevents the elastic deformation of the locking claw 17. Fig.13 In the state shown, the floating arm 5 cannot be installed in the floating arm installation portion 11. In fact, when the floating arm 5 is installed in the floating arm installation portion 11, the retaining frame 7 is rotated relative to the frame 3 to Figure 6 The angle range θ3 shown becomes Fig.14 Status shown.

[0056] If the floating arm 5 is already set on the retaining frame 7, the retaining frame 7 (floating arm 5) is Figure 6 The frame 3 is freely rotatable within a range between the dashed line L1 and the dashed line L4 shown.

[0057] In addition, when the floating arm 5 is set in the middle of the retaining frame 7, Fig.13 The latch claw 17 of the floating arm setting portion 11 shown in FIG. Fig.14 The position indicated by the double-dashed line is elastically deformed.

[0058] When the floating arm 5 is set on the retaining frame 7, Fig.14 As shown by the arrow in the middle, if a force (rotational torque shown by the arrow) is applied to the floating arm 5 in the rightward twisting direction, the floating arm 5 may be separated from the floating arm setting part 11 (fitting part). Fig.14 As shown by the two-dot chain line, the locking claw 17 is elastically deformed, which may cause the float arm 5 to be separated from the float arm setting portion 11 (fitting portion).

[0059] The frame 3 is provided with a protrusion (elastic deformation prevention portion) 13 for limiting the deflection of the snap claw 17 of the retainer 7. Fig.14 When the rotational moment indicated by the arrow in the middle acts on the floating arm 5, for example, Fig.13 As shown, if the floating arm 5 rotates to Figure 6 In the angle range θ1 or θ2 shown, the elastic deformation of the locking claw 17 is prevented by the elastic deformation preventing portion 13 .

[0060] in addition, Fig.12 , Fig.14 Indicates that the floating arm 5 is located at Figure 6 In this state, the latch claw 17 is in the range of the angle θ3 shown in FIG. Fig.14The elastic deformation is shown by the double-dashed line. Fig.13 In the middle, the floating arm 5 is Figure 6 The locking claw 17 is rotated to the position indicated by the dashed line L4 , and the locking claw 17 abuts against the elastic deformation preventing portion 13 , thereby preventing the elastic deformation of the locking claw 17 .

[0061] The liquid level detection device 1 is further described. Figure 2 As shown in FIG. 1 , the liquid level detection device 1 is provided with a terminal 21 and a holding member 23. The terminal 21 and the holding member 23 are respectively assembled to the frame 3. Figure 4 As shown, the terminal 21 is electrically connected to a lead wire 27 of a Hall element 25 provided inside the frame 3 . In addition, a detection line 29 held by the holding member 23 is connected to the terminal 21 , and the detection line 29 is led out from the upper part of the frame 3 .

[0062] like Figure 1 As shown in FIG. 1 , the base end of the floating arm 5 is connected to the retaining frame 7. The other end of the floating arm 5 is a free end, and a float 9 is fixed to the free end. Figure 4 , Figure 2 As shown, the holder 7 is formed in a circular shape (a low-height cylindrical shape) having an annular magnet 31 inside. The holder 7 is attached to the front surface side of the frame 3 and is supported so as to be rotatable.

[0063] like Figure 4 As shown in the figure, the holder 7 has a shaft recess 33 at the center portion of the rear surface side. The magnet 31 is arranged on the inner peripheral side of the shaft recess 33. In addition, on the rear surface side of the holder 7, a guide recess 35 is formed on the outer peripheral side of the magnet 31. In addition, the holder 7 has a pair of flange portions 37 at the edge portion of the rear surface side. These flange portions 37 are arranged at the upper and lower positions of the holder 7 and protrude toward the radial outer side.

[0064] As described above, in the liquid level detection device 1, the floating arm 5 swings as the float 9 moves following the liquid surface, and the holder 7 connected to the floating arm 5 rotates relative to the frame 3. Then, the Hall element 25 in the frame 3 detects the change in the magnetic flux of the magnet 31 of the holder 7, and the detection result is sent to the measuring unit (not shown) via the detection line 29. In the measuring unit, the liquid level is measured based on the detection result from the Hall element 25, and a warning is issued as needed. For example, the measuring unit issues a warning such as the exhaustion of fuel in the fuel tank.

[0065] like Figure 5 and Figure 6 As shown, the frame 3 has a rotation recess 39 on its front surface side for rotatably accommodating the holder 7. The rotation recess 39 is formed in a circular shape in the front view. A shaft 41 is protrudingly provided on the rotation center axis C1 of the rotation recess 39, and the Hall element 25 is provided on the shaft 41.

[0066] like Figure 4 , Figure 5 As shown in the figure, a locking groove 43 is formed in the inner peripheral portion of the rotating recess 39 on the frame 3 along the circumferential direction. In addition, a pair of insertion holes 45 are formed at the front surface side of the frame 3 at the opposite positions of the edge of the rotating recess 39. These insertion holes 45 are formed at the left and right positions of the frame 3 across the rotating recess 39, and are respectively connected to the locking groove 43. In addition, a guide protrusion 47 is formed in the bottom of the rotating recess 39 in the circumferential direction so as to surround the periphery of the shaft portion 41.

[0067] like Fig. 7A , 7B As shown, a floating arm installation portion (arm fixing portion) 11 is provided on the holder 7. The floating arm 5 is fixed to the holder 7 via the floating arm installation portion 11. The floating arm 5 fixed to the holder 7 passes through the rotation center axis C1 of the holder 7. In addition, the rod-shaped floating arm 5 fixed to the holder 7 extends in a direction orthogonal to the rotation center axis C1.

[0068] The floating arm installation portion 11 includes a locking hole 49, a holding portion 51, and a locking portion 53. The locking hole 49 is formed by a hole portion formed to penetrate the holding frame in the front and rear directions, and is formed at a part of the peripheral edge of the holding frame 7. A locking end 55 bent at a right angle is provided at one end, that is, the base end of the floating arm 5. The locking end 55 is inserted into the locking hole 49.

[0069] like Fig. 8A , 8B As shown, the holding portion 51 is formed on the front surface side of the holder 7. The holding portion 51 has a holding piece 57 protruding laterally. A holding groove 59 is formed between the holding piece 57 and the front surface of the holder 7. The base end vicinity of the floating arm 5 is fitted into the holding groove 59 from the side.

[0070] A retaining protrusion 61 is formed at the edge of the retaining piece 57 of the retaining portion 51 and protrudes toward the surface side of the retaining frame 7. The retaining protrusion 61 is formed at a position closer to the tip end side of the floating arm 5 than the rotation center axis C1 of the retaining frame 7. The retaining protrusion 61 gradually protrudes more as it moves away from the locking hole 49. Figure 8B As shown, the tip portion of the holding projection 61 of the holding piece 57 is inclined at an inclination angle θs toward the tip side of the floating arm 5 in a side view relative to the inner surface of the holding piece 57 on the holder 7 side.

[0071] The holding projection 61 has a guide surface 63 on the opening side of the holding groove 59 and a holding surface 65 on the inner side of the holding groove 59. The guide surface 63 is provided as an inclined surface that gradually inclines toward the surface of the holding frame 7 as it goes toward the front side in the insertion direction of the floating arm 5 into the holding groove 59. The holding surface 65 is provided as an inclined surface that gradually inclines toward the surface side of the holding frame 7 as it goes toward the rear side in the insertion direction of the floating arm 5 into the holding groove 59, that is, toward the opening side of the holding groove 59.

[0072] The locking portion 53 is formed on the side of the holding portion 51 opposite to the locking hole 49. The locking portion 53 has a claw portion 67 protruding toward the front side of the holding frame 7. The claw portion 67 locks the peripheral surface of the floating arm 5 inserted into the holding groove 59 of the holding portion 51. The locking portion 53 is formed as a cantilever flexible arm structure connected to a part of the edge of the holding frame 7 and extending along the edge of the holding frame 7 (see Fig. 7A , 7B ). As a result, the locking portion 53 is easily elastically deformed, so that the claw portion 67 can be easily displaced. In addition, the locking portion 53 and the claw portion 67 constitute the above-mentioned locking claw 17.

[0073] In order to assemble the holder 7 to the frame 3, the holder 7 is inserted into the rotation recess 39 while the flange portion 37 of the holder 7 is aligned with the insertion hole 45 of the frame 3. Then, the flange portion 37 passes through the insertion hole 45, and the shaft portion 41 of the frame 3 is inserted into the shaft recess 33 of the holder 7. In addition, the guide protrusion 47 of the frame 3 enters the guide recess 35 of the holder 7.

[0074] Next, the holder 7 inserted into the rotation recess 39 is rotated so that the locking hole 49 is arranged upward. Thus, the flange 37 of the holder 7 enters the locking groove 43 of the frame 3 and prevents the holder 7 from being separated from the rotation recess 39 of the frame 3.

[0075] In order to assemble the floating arm 5 on the retaining frame 7, as shown in FIG. Fig. 7A As shown, the locking end 55 formed at the base end of the float arm 5 is inserted into the locking hole 49 of the retainer 7 .

[0076] Then, if Figure 7B As shown in FIG. 4 , the floating arm 5 is rotated with the locking end 55 inserted into the locking hole 49 as a fulcrum. Then, the base end vicinity of the floating arm 5 is inserted into the holding groove 59 of the holding portion 51 from the side. Fig.9A , 9B As shown, the base end vicinity of the float arm 5 is held by the holding portion 51, and the peripheral surface is locked by the claw portion 67 of the locking portion 53. Thus, the base end side of the float arm 5 is fixed to the holder 7.

[0077] Here, the holding protrusion 61 formed on the holding piece 57 of the holding portion 51 gradually increases in protrusion amount as it moves away from the locking hole 49. Therefore, when the floating arm 5 is inserted into the holding groove 59, the holding piece 57 is gradually lifted up from the locking hole 49 side by the floating arm 5 rotating with the locking end 55 as a fulcrum. In addition, the holding protrusion 61 has a guide surface 63 composed of an inclined surface that gradually inclines toward the surface of the retainer 7 as it moves toward the front side of the insertion direction of the floating arm 5 into the holding groove 59. Therefore, when the floating arm 5 is inserted into the holding groove 59, the guide surface 63 contacts the floating arm 5, and the holding piece 57 is smoothly lifted up. Therefore, by rotating the floating arm 5 with the locking end 55 as a fulcrum, the floating arm 5 can be easily inserted into the holding groove 59 of the holding portion 51 with a small force.

[0078] The locking portion 53 is formed into a cantilever flexible arm structure connected to a part of the edge of the holder 7 and extending along the edge of the holder 7. The locking portion 53 can easily displace the claw portion 67 by elastic deformation. Therefore, when the floating arm 5 is inserted into the holding groove 59 of the holding portion 51, the locking portion 53 of the cantilever flexible arm structure is elastically deformed smoothly, and the peripheral surface of the floating arm 5 inserted into the holding groove 59 is locked by the claw portion 67.

[0079] like Fig.10 As shown, the floating arm 5 held by the retaining frame 7 may contact surrounding components during assembly, and a load F may be applied in a direction intersecting the swing direction of the floating arm 5. If such a load F is applied to the floating arm 5, Fig.10 As shown by the two-dot chain line, the displacement amount of the floating arm 5 gradually increases toward the distal end side.

[0080] In the liquid level detection device 1 according to the embodiment, the retaining protrusion 61 is provided at a position on the tip side of the float arm 5 with respect to the rotation center axis C1 of the holder 7 in the edge portion of the retaining piece 57 of the retaining portion 51, the retaining protrusion 61 gradually increasing in protrusion amount as it moves away from the locking hole 49. Therefore, even if the retaining piece 57 is lifted by applying a load F in a direction intersecting the swinging direction of the float arm 5, it is possible to suppress the float arm 5 from coming out of the retaining groove 59 of the retaining piece 57.

[0081] In addition, in the liquid level detection device 1, the holding portion 51 has the holding protrusion 61 at the edge of the holding piece 57, and the holding protrusion 61 has the holding surface 65 composed of an inclined surface that gradually inclines toward the surface of the retainer 7 toward the opening side of the holding groove 59. Therefore, even if the load F is applied in a direction intersecting the swing direction of the float arm 5 to lift the holding piece 57, the inclination angle of the holding surface 65 with respect to the surface of the retainer 7 is unlikely to become an angle that opens in the direction in which the float arm 5 is separated from the retainer 7. Therefore, it is possible to further suppress the float arm 5 engaged with the claw portion 67 of the engaging portion 53 from being separated from the holding groove 59.

[0082] In the liquid level detection device 1 according to the embodiment, the float arm 5 is rotated with the locking end 55 inserted into the locking hole 49 as a fulcrum and is fitted into the holding groove 59 of the holding portion 51. Thus, the float arm 5 can be locked by the holding protrusion 61 of the holding piece 57 and the claw 67 of the locking portion 53 and fixed to the holder 7.

[0083] Here, the amount of protrusion of the holding protrusion 61 formed on the holding piece 57 of the holding portion 51 gradually increases as it moves away from the locking hole 49. That is, when a load F is applied in a direction intersecting the swing direction of the floating arm 5, the amount of protrusion of the holding protrusion 61 gradually increases in a direction in which the displacement of the floating arm 5 increases. Thus, it is possible to suppress the floating arm 5 from coming out of the holding groove 59 when the load F is applied to the floating arm 5 in a direction intersecting the swing direction.

[0084] In addition, the amount of protrusion of the holding projection 61 gradually increases as it moves away from the locking hole 49. According to this structure, when the floating arm 5 is inserted into the holding groove 59, the floating arm 5 is smoothly inserted into the holding groove 59 from the locking hole 49 side. Therefore, by rotating the floating arm 5 with the locking end 55 inserted into the locking hole 49 as a fulcrum, the floating arm 5 can be easily held on the holding portion 51 with a small force.

[0085] In addition, the holding projection 61 has a holding surface 65 that is inclined toward the surface side of the retaining frame 7 toward the opening side of the holding groove 59. Therefore, even if the load F is applied in a direction intersecting the swing direction of the floating arm 5 and the holding piece 57 is deformed, the inclination angle of the holding surface 65 is unlikely to become an angle that opens in the direction in which the floating arm 5 is separated from the retaining frame 7 with respect to the surface of the retaining frame 7. Therefore, it is possible to further suppress the floating arm 5 from coming out of the holding groove 59.

[0086] The locking portion 53 is a cantilevered flexible arm structure extending from the retaining frame 7. Therefore, when the floating arm 5 inserted into the retaining groove 59 contacts, the locking portion 53 is easily bent. Since the locking portion 53 has a cantilevered flexible arm structure, the floating arm 5 can be easily inserted into the retaining groove 59 with less force, and can be retained by the retaining portion 51.

[0087] Here, the elastic deformation preventing portion 13 is further described in detail. The elastic deformation preventing portion 13 is formed in an arc column shape. The cross-sectional shape of the elastic deformation preventing portion 13 that is orthogonal to the extension direction of the center of the arc extension is a rectangle. Further, the elastic deformation preventing portion 13 is formed as: a rectangle of a specified plane is drawn, and when the above-mentioned rectangle is rotated by a specified angle around the rotation axis, a three-dimensional shape represented by the trajectory of the above-mentioned rectangle. Here, the specified angle of rotation is, for example, 20°. In addition, the above-mentioned rotation axis is separated from the above-mentioned rectangle by a specified distance and extends parallel to a specified one of the four sides of the above-mentioned rectangle. Moreover, the elastic deformation preventing portion 13 is arranged on the frame 3 in a manner that the above-mentioned rotation axis is consistent with the rotation center axis C1 of the retaining frame 7 (floating arm 5). In addition, the elastic deformation preventing portion 13 is integrally formed with the frame 3.

[0088] In addition, the elastic deformation preventing portion 13 protrudes from the inner surface of the rotation recess 39 toward the rotation center axis C1 side of the retainer 7 (floating arm 5). Figure 6 As shown in FIG. 1 and FIG. 2 , when viewed in the extension direction of the rotation center axis C1, the elastic deformation preventing portion 13 is provided at two locations. The positions of the elastic deformation preventing portions 13 provided at the two locations in the extension direction of the rotation center axis C1 are consistent with each other. The position of the buckle claw 17 in the extension direction of the rotation center axis C1 in the normal state is arranged at a position that does not interfere with the elastic deformation preventing portion 13. That is, Fig.14 In a normal use state where the rotational moment indicated by the middle arrow does not act on the floating arm 5 , the elastic deformation preventing portion 13 and the locking claw 17 are separated from each other in the extending direction of the rotation center axis C1 and do not interfere with each other.

[0089] like Figure 1 As shown, the central axis of the floating arm 5 is at Figure 6 In the state shown by the dotted line L4 in the middle, the liquid level detection device 1 is set in the fuel tank (not shown). At this time, even if the float 9 hits the edge of the open part of the fuel tank, Fig.14 The rotational moment indicated by the middle arrow acts on the float arm 5, and the locking claw 17 also hits the elastic deformation preventing portion 13. Thus, the deformation of the locking claw 17 is suppressed, and the float arm 5 is prevented from being separated from the float arm setting portion 11.

[0090] When the liquid level detection device 1 is already installed in the fuel tank, no abnormally large force is applied to the float arm 5 and the float 9. Figure 6 Even within the range of the angle θ3 shown, the float arm 5 will not be separated from the float arm installation portion 11 .

[0091] In addition, when the liquid level detection device 1 replaces the float arm 5, the liquid level detection device 1 is removed from the fuel tank. Figure 6When the angle θ3 is within the range shown, the float arm 5 can be easily removed from the holder 7 and installed in the holder 7 .

[0092] The liquid level detection device 1 is provided with an elastic deformation prevention portion 13 that prevents elastic deformation of a portion of the float arm installation portion 11. This prevents the device from becoming larger and having more parts, and improves the holding strength of the float arm 5 in the holder 7.

[0093] That is, if the locking claw 17 is made stronger, the strength can be improved, but the device will be larger, resulting in poor assembly of the float arm 5 to the holder 7. In addition, if a component is provided separately to prevent the elastic deformation of the locking claw 17, the number of components of the device will increase. In contrast, in the liquid level detection device 1, since the elastic deformation prevention portion 13 is integrally provided on the frame 3, it is possible to prevent the device from being larger and the number of components of the device from being increased, and the holding strength of the holder 7 for the float arm 5 can be improved.

[0094] In a liquid level detection device that does not include the elastic deformation preventing portion 13 as in the embodiment, Fig.14 When the rotational torque indicated by the middle arrow is applied to the floating arm 5, the buckle claw 17 will react as follows: Fig.14 Due to the elastic deformation shown by the two-dot chain line, there is a possibility that the float arm 5 will fall off from the retainer 7.

[0095] In the liquid level detection device 1, when the rotation angle of the holder 7 relative to the frame 3 is only within the predetermined rotation angle range θ1, θ2, the elastic deformation prevention portion 13 is configured to prevent a portion of the floating arm installation portion 11 from being elastically deformed. Thus, the floating arm 5 can be installed on the holder 7 in a state where the holder 7 is installed on the frame 3.

[0096] Alternatively, the elastic deformation preventing portion 13 may be configured to prevent elastic deformation of a portion of the floating arm installation portion 11 regardless of the rotation angle of the retainer 7 relative to the frame 3. In this case, the retainer 7 may be installed on the frame 3 after the floating arm 5 is installed on the retainer 7.

[0097] In the liquid level detection device 1, the predetermined rotation angle range for preventing elastic deformation of a part of the float arm installation portion 11 is the rotation angle range θ1 and the rotation angle range θ2, except for the rotation angle range θ3 when the float arm 5 is installed in the holder 7. Thus, the elastic deformation of a part of the float arm installation portion 11 can be more reliably prevented, and the float arm 5 installed in the holder 7 is less likely to fall off the holder 7.

[0098] In the liquid level detection device 1, the predetermined rotation angle ranges θ1 and θ2 that prevent elastic deformation of a part of the float arm installation portion 11 are angles when the frame 3 (liquid level detection device 1) is assembled to a tank as a liquid level detection object. Thus, when the liquid level detection device 1 is assembled to a fuel tank, even if an excessive load is applied to the float arm installation portion 11 due to the float 9 accidentally hitting the fuel tank, the float arm 5 can be prevented from being detached from the float arm installation portion 11.

[0099] Although specific embodiments have been described, these embodiments are presented only by way of example and are not intended to limit the scope of the invention. In fact, the novel embodiments described herein may be embodied in a variety of other forms. In addition, various omissions, substitutions, and changes may be made to the forms of the embodiments described herein without departing from the gist of the present invention. The accompanying claims and their equivalents are intended to cover such forms or modifications that fall within the scope and gist of the present invention.

Claims

1. A liquid level detection device (1), characterized in that: have: Framework (3); Floating arm (5); A retaining frame (7), the retaining frame (7) being rotatably supported on the frame (3); a floating arm setting portion (11), the floating arm setting portion (11) being set on the retaining frame (7), the floating arm setting portion (11) being configured to set the floating arm (5) by elastically deforming a first portion when the floating arm (5) is set on the retaining frame (7) and restoring the first portion when the floating arm (5) has been set on the retaining frame (7); a float (9), the float (9) being disposed on the floating arm (5) away from the retaining frame (7); and an elastic deformation preventing portion (13), the elastic deformation preventing portion (13) being arranged on the frame (3) and preventing the elastic deformation of the first portion of the floating arm setting portion (11), The elastic deformation preventing portion (13) is configured to prevent elastic deformation of the first portion of the floating arm setting portion (11) when the rotation angle of the retaining frame (7) relative to the frame (3) is within a predetermined rotation angle range (θ1, θ2).

2. The liquid level detection device (1) according to claim 1 is characterized in that: The predetermined rotation angle range (θ1, θ2) is a rotation angle range excluding a rotation angle range (θ3) when the floating arm (5) is installed on the retaining frame.

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