JP6213288B2 - Liquid level detector - Google Patents

Description

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

  2. Description of the Related Art Conventionally, a liquid level detection device that detects a liquid level height of a liquid stored in a container is known. The liquid level detection device disclosed in Patent Document 1 is held by a fixed body fixed to a container, a rotating body that performs a rotational movement following a change in the liquid level, and a fixed body. A plurality of electrodes arranged in the rotational direction of the rotational movement, and a first contact and a second contact are provided. And the 1st contact and the 2nd contact are formed by the common arm part, and are formed so that it may connect with a different electrode, respectively.

JP 2003-322555 A

  In the liquid level detection device of Patent Document 1, it is understood that the first contact and the second contact slide with the contact start angle shifted in the rotation direction.

  Therefore, the present inventor sets the deviation of the contact start angle between the first contact and the second contact within the range of the electrode to be contacted, so that one of the contacts is attached due to adhesion of foreign matter to the electrode. The liquid level detection device that can detect the electric resistance even when the electrode does not contact the same electrode as the contact object was studied.

  However, in the liquid level detection device of Patent Document 1, since the first contact and the second contact are formed by a common arm portion, when one contact rides on the electrode due to a deviation of the contact start angle, the other contact Makes it difficult to come into contact with the electrode. Accordingly, it has been found that the purpose of contacting the same electrode cannot be achieved. In addition, when one contact rides on a foreign substance adhering to the electrode, the other contact is lifted, making it difficult for both contacts to come into contact with the electrode, making it impossible to detect the electrical resistance.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a liquid level detection device that accurately detects the liquid level height.

One of the disclosed inventions is a liquid level detection device for detecting the liquid level height of a liquid stored in a container, and follows a fixed body fixed to the container and a change in the liquid level height. A rotating body that performs a rotational motion, and a plurality of electrodes that are held by a fixed body, arranged in the rotational direction of the rotational motion, and that form a convex portion having a curvature in the rotational direction, and are electrically connected to each other, A curved convex first contact and a second contact that are elastically contacted with the electrode by being pressed against the electrode; and two arm portions that are held against the rotating body and can be elastically deformed independently. The liquid surface height is detected by an electrical resistance when at least one of the first contact and the second contact is elastically contacted with the electrode, and each arm portion is rotated in a rotational direction from a fixed end connected to the rotating body. Formed in the shape of a leaf spring extending to the free end along the first Point and the second contact being formed respectively on the free end of each arm portion, the first contact and the second contact for contacting the electrode of the object location in accordance with the rotational movement, the rotational direction contact start angle The displacement of the contact start angle is within the range of the electrode to be contacted.

  According to such an invention, in order to detect the liquid surface height by electric resistance, the first contact that is elastically contacted with the plurality of electrodes that are arranged in the rotational direction of the rotational motion and that form the convex portion having the curvature in the rotational direction; The second contact point slides with the contact start angle shifted in the rotation direction with respect to the electrode to be contacted. According to this, the peak of the force in the rotational direction that each contact receives from the electrode at the contact start angle is shifted. Accordingly, since the peak value and fluctuation of the sliding torque received by the rotating body due to this force are reduced, the rotating body smoothly rotates when the contact point slides, and the liquid level can be detected with high accuracy. In this case, since the first contact and the second contact are respectively formed on two arm portions that can be elastically deformed independently, even if they are located at different locations on the electrode, each of the electrodes is caused by independent elastic deformation. It can slide in an elastic contact state according to the shape. Since the deviation between the first contact and the second contact is set within the range of the electrodes to be contacted, the first contact and the second contact can simultaneously contact the same electrode, and one contact is an electrode. Even when riding on a foreign substance adhering to the electrode, the other contact may be able to contact the electrode. By the above, the liquid level detection apparatus which detects a liquid level height accurately can be provided by suppressing a contact failure.

  In addition, another aspect of the disclosed invention is characterized in that the deviation is ½ of the pitch in the array.

  When the deviation between the first contact and the second contact coincides with an integral multiple of the pitch of the array, the fluctuation waveform of the rotational force received from the electrode when each contact slides overlaps, and the deviation is 1 / When it is shifted by 2, the fluctuation waveform is most shifted. Therefore, in the present invention, by setting the deviation to ½ of the arrangement pitch, the peak value and fluctuation of the sliding torque received by the rotating body due to the force can be minimized.

  In addition, in another one of the disclosed inventions, the rotation direction includes an ascending rotation direction corresponding to a rotating motion following an increase in liquid level and a descending rotating direction corresponding to a rotating motion following descending. In addition, each of the arm portions is formed in a leaf spring shape extending from a fixed end connected to the rotating body to a free end on the descending rotation direction side along the rotation direction.

  When the rotating body performs a rotational motion in the upward rotation direction, the rotational body performs a rotational motion against gravity, so that the rotational body is difficult to rotate smoothly as compared to the downward rotation direction. On the other hand, when the rotation direction of the rotating body is the direction from the fixed end to the free end, the free end of the arm portion is sandwiched between the fixed end and the electrode when each contact point runs on the electrode. Thus, since the degree of freedom is reduced, elastic deformation is difficult. Therefore, in this case, as compared with the case of the direction from the free end to the fixed end, the force in the rotational direction that each contact receives from the electrode increases, and the rotating body is difficult to rotate smoothly. In this respect, in the arm portion formed in the shape of a leaf spring extending from the fixed end connected to the rotating body to the free end on the descending rotation direction side along the rotation direction, the direction from the fixed end to the free end is The direction is the reverse of the upward rotation direction. Therefore, the rotating body can be prevented from being extremely difficult to rotate only in a specific direction, and can be rotated smoothly in both directions. As described above, the liquid level can be accurately detected.

It is a front view which shows the liquid level detection apparatus in 1st Embodiment. It is a front view which shows a part of fixed body and arrangement | positioning of several electrodes in 1st Embodiment. It is a cross-sectional perspective view which shows the rotation direction cross section about one electrode in FIG. It is sectional drawing which shows the rotation direction cross section for demonstrating the force which a contact receives from an electrode, Comprising: It is a figure which shows the case where a contact contacts at the vertex part of an electrode. It is sectional drawing which shows the rotation direction cross section for demonstrating the force which a contact receives from an electrode, Comprising: It is a figure which shows the case where a contact contacts in the convex part of an electrode. It is a front view which shows typically a mode that the contact in 1st Embodiment slides with respect to an electrode. It is a graph which shows typically sliding torque in a 1st embodiment. It is sectional drawing which shows the rotation direction cross section for demonstrating the position of each contact in state SA in FIG. It is sectional drawing which shows the rotation direction cross section for demonstrating the position of each contact in the state SB in FIG. It is sectional drawing which shows the rotation direction cross section for demonstrating the position of each contact in the state SC in FIG. It is a front view which shows typically a mode that the contact in 2nd Embodiment slides with respect to an electrode. It is sectional drawing which shows the rotation direction cross section for demonstrating the position of each contact in the rotation end in 3rd Embodiment. It is sectional drawing which shows the rotation direction cross section for demonstrating the position of each contact in the rotation end in 4th Embodiment. It is a front view which shows typically a mode that the contact in the modification 1 slides with respect to an electrode.

  Hereinafter, a plurality of embodiments of the present invention will be described with reference to 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 of the present invention is installed in a fuel tank 1 mounted on a vehicle. The fuel tank 1 stores fuel as a liquid, and the liquid level detection device 100 detects a liquid level height that is the height of the liquid level 1a of the fuel. The liquid level detection device 100 mainly includes a fixed body 10, a rotating body 30, a plurality of electrodes 40, and two arm portions 60a and 60b.

  The fixed body 10 includes a housing 12, an electrode side terminal 14, a contact side terminal 16, a substrate 18, a resistor 20, and the like. The housing 12 of the fixed body 10 is formed into a container shape and is fixed to the fuel tank 1 with a synthetic resin such as polyacetal resin or polyphenylene sulfide resin having excellent oil resistance, solvent resistance, and mechanical properties.

  The electrode-side terminal 14 is held by the housing 12 and is formed in a plate shape by a conductive material such as phosphor bronze. One end of the electrode-side terminal 14 is in contact with the substrate 18 and is electrically connected to the upper electrode 40a among the plurality of electrodes 40 described in detail later. The other end of the electrode side terminal 14 is electrically connected to an external device via the lead wire 22.

  The contact-side terminal 16 is held by the housing 12 and is formed in a plate shape by a conductive material such as phosphor bronze. One end of the contact-side terminal 16 is electrically connected to the sliding member 50 held by the rotating body 30 via the connection member 17. The other end of the electrode side terminal 14 is electrically connected to an external device via the lead wire 22.

  The substrate 18 is held in the housing 12 and is formed in a plate shape with ceramics or the like in order to hold the resistor 20 and the plurality of electrodes 40.

  As shown in detail in FIG. 2, the resistor 20 is formed in a thick strip shape by printing and baking a paste in which ruthenium oxide and glass frit are mixed on the substrate 18, and electrically connects the plurality of electrodes 40. Connect to.

  As illustrated in FIG. 1, the rotating body 30 includes a float 32, a rotating rod 34, and a rotating holder 36. As shown in FIG. 1, the float 32 is made of a material having a specific gravity smaller than that of a fuel such as foamed ebonite. The float 32 can float on the liquid level 1a of the fuel by buoyancy generated in the direction opposite to the gravity. The volume of the float 32 is set in consideration of the size of the fuel tank 1 and a sliding torque N described later.

  The rotating rod 34 is formed of a round bar-shaped core material using a metal material such as stainless steel. A float 32 is held at one end of the rotating rod 34. The other end of the rotating rod 34 forms a rotating shaft 34 a and is held by a rotating holder 36 and penetrates the housing 12 (not shown).

  The rotating holder 36 is made of a synthetic resin such as polyacetal resin or polyphenylene sulfide resin. The rotation holder 36 has a boss portion 36a that fixes the rotation shaft 34a of the rotation rod 34, and is held rotatably with respect to the fixed body 10 by the boss portion 36a.

  In this way, the rotating body 30 is held rotatably with respect to the fixed body 10, and performs a rotational motion following the change in the liquid level by the buoyancy generated in the float 32. The rotational direction DR of the rotator 30 includes an ascending rotational direction DRU corresponding to the rotational motion following the rise in the liquid level and a descending rotational direction DRD corresponding to the rotational motion following the descending. The rotating body 30 forms rotating ends 38a and 38b whose mechanical range is limited by a stopper (not shown), for example. The rotation ends 38a and 38b are set in each of the upward rotation direction and the downward rotation direction.

  As shown in detail in FIG. 2, the plurality of electrodes 40 are formed in a thick film by printing and baking a paste in which silver, palladium, and glass frit are mixed on the substrate 18. ing. The plurality of electrodes 40 are arranged on the surface of the substrate 18 in the rotational direction DR of the rotational movement with a gap therebetween. Further, when viewed from the front, each electrode 40 has a width outside the radial direction DD larger than that inside the radial direction DD of the rotational motion, and is formed in a fan shape like a donut cut. Further, the edge 42 where the plurality of electrodes 40 are spaced from each other is inclined with respect to the radial direction DD of the rotational motion.

  As shown in FIG. 3, the thickness of each electrode 40 gradually increases from the edge 42 toward the center of the electrode 40. Accordingly, the convex surface portion 44 having a curvature in the rotation direction DR of each electrode 40 is formed both inside and outside the radial direction DD. Since such a convex surface portion 44 is formed using, for example, the surface tension of the paste, there is no significant difference in curvature both inside and outside the radial direction DD. Therefore, on the outer side in the radial direction DD, a relatively flat portion is formed between the convex surface portions 44 at the edge portions 42 on both sides. And the apex part 46 where inclination becomes the smallest in the center of the electrode 40 is provided in the radial direction DD inner side and the radial direction DD outer side. In FIG. 3, the cross-sectional shape inside the radial direction DD is shown by a solid line, and the cross-sectional shape outside the radial direction DD is shown surrounded by a broken line.

  Further, as shown in FIG. 2, the portions of each electrode 40 on the outer side in the radial direction DD with respect to a contact point with a second contact 66b described later are arranged in parallel to each other, and each electrode 40 is arranged on the surface of the resistor 20. Each electrode 40 is electrically connected through the resistor 20.

  The two arm parts 60a and 60b constitute the main part of the sliding member 50 as shown in FIG. The sliding member 50 is formed in a U-shape, and includes a connecting portion 52 and two arm portions 60a and 60b formed on both sides sandwiching the connecting portion 52. The connecting portion 52 is formed integrally with each arm portion 60a-b by a conductive material such as phosphor bronze, and connects the two arm portions 60a-b and the rotating holder 36 of the rotating body 30. . Further, the connecting portion 52 is electrically connected to the contact-side terminal 16 via the connection member 17.

  In this way, the arm portions 60 a and 60 b are held with respect to the rotation holder 36 of the rotating body 30. And since the part except the 1st contact 66a and the 2nd contact 66b mentioned later among each arm part 60a-b is formed with electroconductive materials, such as phosphor bronze, each arm part 60a-b is respectively It is elastically deformable independently. Specifically, each arm part 60a-b is a plate extending from the fixed end 62a-b connected to the rotating body 30 to the free end 64a-b on the descending rotational direction DRD side along the rotational direction DR. It is formed in a spring shape. And the 2nd contact 66b arrange | positioned in radial direction DD outer side with respect to the 1st contact 66a and the 1st contact 66a, respectively is formed in the free end 64a-b side of each arm part 60a-b. Further, the first contact 66a and the second contact 66b are arranged along the radial direction DD.

  The first contact 66a and the second contact 66b are formed by melting a metal material containing 95% or more, preferably 99% or more, of gold by heat and bonding the metal material to each of the arm portions 60a and 60b. The first contact 66a and the second contact 66b have curved convex shapes toward the plurality of electrodes 40 on the fixed body 10 side of the arm portions 60a and 60b. The first contact 66 a and the second contact 66 b are electrically connected to each other through the connecting portion 52. And the 1st contact 66a and the 2nd contact 66b are elastically contacted with the electrode 40 by respectively pressing against the electrode 40 by elastic deformation of a leaf | plate spring shape.

  In this way, at least one of the first contact 66a and the second contact 66b and the electrode 40 are in elastic contact with each other, so that a circuit through the resistor 20 is provided between the electrode side terminal 14 and the contact side terminal 16. Is configured. When the rotator 30 rotates following the change in the liquid level, the sliding member 50 held by the rotator 30 slides, and the electrodes 40 to which the respective contacts 66a-b come into contact are slid. The electric resistance corresponding to the electrode 40 can be detected by changing the conductive path of the resistor 20. The two arm portions 60 a and 60 b have sufficiently small specific resistance with respect to the resistor 20.

  Hereinafter, such sliding of the sliding member 50 will be described in detail. First, attention is paid to sliding of one contact 66a or 66b. Each contact 66a-b slides relative to the electrode along the rotational direction DR corresponding to the rotational motion. Here, as an example, a case of sliding in the downward rotation direction DRD will be described. As shown in FIGS. 4 and 5, each contact 66 a-b slides while changing the elastic deformation state of the arm portions 60 a-b by the convex surface portion 44 of the electrode 40. For example, when contacting the vicinity of the edge portion 42 of the electrode 40 at a position corresponding to the rotational motion, the elastic deformation of the arm portions 60 a to 60 b is small, and the arm portions 60 a to 60 a are moved closer to the apex portion 46 of the electrode 40. The elastic deformation of b is in a large state. Each contact 66a-b contacts in a pressed state at any location of the electrode 40 while the arm portions 60a-b are elastically deformed according to the film thickness of the electrode 40, and is reliably electrically connected. It is like that. When each contact 66a-b slides and reaches the gap between the electrodes 40, contact with the next adjacent electrode 40 is started, and one contact 66a or 66b temporarily contacts the two electrodes 40. Immediately thereafter, the state is brought into contact with the next electrode 40. That is, the gaps between the electrodes 40 are set so that the curved convex contacts 66a-b do not directly contact the substrate, so that even when each contact 66a-b moves to the next electrode 40 by rotational movement. , It is always in contact with one or more electrodes 40.

  The force that each contact 66 a-b receives from the electrode 40 varies depending on the contact state with the electrode 40. As shown in FIG. 4, when the contacts 66 a-b are in contact with each other at the apex portion 46 of the electrode 40, the normal direction of the contact portion is substantially perpendicular to the rotation direction DR, and the contacts 66 a-b are perpendicular to the electrode 40. The rotational direction component PR of the pressure PN received as a drag force hardly occurs. Therefore, the force in the rotational direction DR that each contact 66a-b receives from the electrode 40 is only the frictional force F generated in the upward rotational direction DRU according to the pressure PN. On the other hand, as shown in FIG. 5, when each contact 66 a-b is in contact with the convex surface portion 44 of the electrode 40, the normal direction of the contact portion is an oblique direction, and each contact 66 a-b is a vertical drag from the electrode 40. There is a rotational direction component PR of the pressure PN. Accordingly, the force in the rotational direction DR that each contact 66a-b receives from the electrode 40 becomes the rotational direction component PR and the rotational direction component FR of the frictional force F. Note that the rotation direction component PR has the smallest angle formed between the normal direction of the contact point and the rising rotation direction DRU at the contact start point PS where contact with the next electrode 40 starts to be started. Become the largest. That is, the force in the rotational direction DR that each contact 66a-b receives from the electrode 40 has a peak that becomes the largest in the upward rotation direction DRU at the contact start point PS, and gradually decreases as each contact 66a-b approaches the apex 46. Become.

  Here, the case of sliding in the descending rotation direction DRD has been described as an example. However, even when sliding in the upward rotation direction DRU, the description can be applied with the rotation direction DR reversed.

  As shown in FIG. 6, the edge 42 is inclined with respect to the radial direction DD. The pitch in the arrangement of the plurality of electrodes 40 is a predetermined value PT. Further, the distance from the rotating shaft 34a to the first contact 66a is L1, and the distance from the second contact 66b is L2. Here, the pitch PT is defined as an angle between the contact start point PS of the electrode 40 and the contact start point PS of the next electrode 40 adjacent to the rotation axis 34a. Next to the contact start point PS of the electrode 40 by each electrode 40 whose width on the outer side of the radial direction DD is larger than the inner side of the radial direction DD corresponding to the length of the arc according to the distances L1 and L2. The angle formed by the contact start point PS of the electrode 40 with respect to the rotation axis 34a is set substantially equal at both the contact start point PS of the first contact 66a and the contact start point PS of the second contact 66b. .

  When the first contact 66a and the second contact 66b in the first embodiment slide, the contact start angle is shifted in the rotation direction DR with respect to the electrode 40 to be contacted at a position corresponding to the rotational motion. Here, the contact start angle indicates the rotation angle θ of the rotating body 30 at the contact start point PS. In particular, in the present embodiment, since the first contact 66a and the second contact 66b are arranged along the radial direction DD, the displacement of the contact start angle is simply caused by the contact start point PS of the first contact 66a and the second contact point. An angle formed by the contact start point PS of the contact 66b with respect to the rotation shaft 34a. The deviation is set to ½ of the pitch PT. In this case, the sliding torque N depending on the rotation angle θ of the rotating body 30 has a fluctuation waveform as shown in FIG. The sliding torque N is the torque that the rotating body 30 receives by the force in the rotation direction DR that each contact 66a-b receives from the electrode 40. That is, the sliding torque N is the sum of the moment M1 of the force in the rotational direction DR received by the first contact 66a from the electrode 40 and the moment M2 of the force in the rotational direction DR received by the second contact 66b from the electrode 40. As the sliding torque N increases, the rotational movement of the rotating body 30 is hindered.

  In the present embodiment, the timing at which the first contact 66a starts to contact the electrode 40 at a position corresponding to the rotational motion, and the timing at which the second contact 66b starts to contact the electrode 40 at the position corresponding to the rotational motion; Is shifted. For this reason, the peak value and the fluctuation of the sliding torque N are reduced by shifting the force peaks from each other. While the rotating body 30 slides by one pitch, the peak values PA and PB of the sliding torque N are dispersed twice. Specifically, at the position of each contact 66a-b corresponding to the state SA of FIG. 7 at the peak value PA where the sliding torque N is the largest, the first contact 66a contacts at the apex 46 as shown in FIG. The second contact 66b is in contact at the contact start point PS. That is, the state SA corresponds to the contact start angle at the second contact 66b. At the position of each contact 66a-b corresponding to the state SB of FIG. 7 at the peak value PB at which the other sliding torque N increases, as shown in FIG. 9, the first contact 66a contacts at the contact start point PS, The second contact 66 b is in contact with the apex portion 46. That is, the state SB corresponds to the contact start angle at the first contact 66a. Since the moment M2 at the second contact 66b is larger than M1 due to the relationship L2> L1, the peak value PA of the sliding torque N in the state SA and the state SB is larger than PB. In this way, the two arm portions 60a and 60b are elastically deformed independently, and even if the contacts 66a and 66b are at different positions, they are in contact with each other in a pressed state and are reliably electrically connected. It has become so.

  The deviation is set to ½ of the pitch PT, and is within the range of the electrode 40 to be contacted. Therefore, the first contact 66a and the second contact 66b are in contact with the same electrode 40 from the state SB to the state SA shown in FIG.

  As shown in FIG. 10, the first contact 66a and the second contact 66b are stopped in a state SC in contact with the same electrode 40 at both rotation ends 38a and 38b. When the electrical resistance corresponding to the rotation end 38a in the ascending rotation direction DRU is detected, the external device indicates the maximum liquid level, that is, the fuel in the fuel tank 1 is “FULL”. When the electric resistance corresponding to the rotation end 38b in the descending rotation direction DRD is detected, the external device indicates the minimum value of the liquid level, that is, the fuel in the fuel tank 1 is “EMPTY”. 8 to 10, the upper stage shows the position of the second contact 66b in the rotational direction DR cross section outside the radial direction DD, the lower stage shows the position of the first contact 66a in the rotational direction DR cross section inside the radial direction DD, The correspondence relationship in the radial direction DD is indicated by a one-dot chain line connecting the upper and lower stages. In FIG. 10, the alternate long and short dash line connecting the upper and lower stages also indicates the position of the rotation end 38b in the descending rotation direction DRD.

(Function and effect)
The operational effects of the first embodiment described above will be described below.

  According to the first embodiment, in order to detect the liquid level height by electric resistance, it is elastically contacted with the plurality of electrodes 40 that form the convex surface portion 44 that is arranged in the rotational direction DR of the rotational motion and has a curvature in the rotational direction DR. The first contact 66a and the second contact 66b slide with respect to the contact target electrode 40 while shifting the contact start angle in the rotation direction DR. According to this, the peak of the force in the rotational direction DR received by each contact 66a-b from the electrode 40 at the contact start angle is shifted. Therefore, since the peak values PA, PB and fluctuations of the sliding torque N received by the rotating body 30 by this force are reduced, the rotating body 30 rotates smoothly when the respective contacts 66a-b slide, and the liquid level The height can be detected accurately. In this case, the first contact 66a and the second contact 66b are formed on the two arm portions 60a and 60b that can be elastically deformed independently of each other. It can be slid in an elastic contact state according to the shape of the electrode 40 by elastic deformation. Since the deviation between the first contact 66a and the second contact 66b is set within the range of the electrode 40 to be contacted, the first contact 66a and the second contact 66b can simultaneously contact the same electrode 40, and Even when one contact 66a or 66b rides on a foreign substance attached to the electrode 40, the other contact 66a or 66b may be able to contact the electrode 40. By the above, the liquid level detection apparatus 100 which detects a liquid level height accurately can be provided by suppressing a contact failure.

  Further, when the deviation between the first contact 66a and the second contact 66b coincides with an integral multiple of the pitch PT of the arrangement, the fluctuation waveform of the force in the rotational direction DR received from the electrode 40 when each contact 66a-b slides is obtained. When the overlap and shift are shifted from the integral multiple by ½, the fluctuation waveform is most shifted. Therefore, in the first embodiment, by setting the deviation to ½ of the pitch PT of the arrangement, the peak values PA and PB and fluctuations of the sliding torque N received by the rotating body 30 due to the force can be minimized. it can.

  When the rotating body 30 rotates in the ascending rotation direction DRU, the rotating body 30 rotates against the gravity. Therefore, the rotating body 30 is difficult to rotate smoothly as compared with the case of the descending rotation direction DRD. On the other hand, when the rotation direction DR of the rotating body 30 is the direction from the fixed ends 62a to 62b of the arm portions 60a to 60b to the free ends 64a to 64b, The free ends 64a and 64b are in a state of being sandwiched between the fixed ends 62a and 62b and the electrode 40, and the degree of freedom is reduced, so that it is difficult to elastically deform. Therefore, in this case, the force in the rotational direction DR received by each contact 66a-b from the electrode 40 is larger than that in the direction from the free ends 64a-b to the fixed ends 62a-b, and the rotating body 30 rotates smoothly. It becomes difficult to do. In this regard, according to the first embodiment, the fixed end 62a-b connected to the rotating body 30 is shaped like a leaf spring extending from the fixed end 62a-b to the free end 64a-b on the descending rotational direction DRD side along the rotational direction DR. In the formed arm portions 60a-b, the direction from the fixed ends 62a-b to the free ends 64a-b is opposite to the upward rotation direction DRU. Therefore, the rotating body 30 can be prevented from being extremely difficult to rotate by the specific direction DRU or DRD, and both the directions DRU and DRD can be rotated smoothly. As described above, the liquid level can be accurately detected.

  In addition, according to the first embodiment, the first contact 66a and the second contact 66b are stopped in contact with the same electrode 40 at the rotation ends 38a to 38b where the rotational motion of the rotating body 30 is limited. It is possible to reliably detect the electrical resistance by preventing the contact points 66 a and 66 b from coming into contact with the electrode 40. Therefore, the maximum value or the minimum value of the liquid level corresponding to the rotation ends 38a and 38b can be reliably detected.

  Further, according to the first embodiment, the edge 42 where the plurality of electrodes 40 are spaced from each other is inclined with respect to the radial direction DD of the rotational motion. According to this, it can manufacture easily only by changing the pattern printing of the electrode 40.

  Further, according to the first embodiment, the rotator 30 has the float 32 that floats on the liquid level 1 a of the fuel, and performs the rotational motion by the buoyancy generated in the float 32. According to this, since the volume of the float 32 can be set small as the peak values PA and PB of the sliding torque N become small, the maximum liquid level height from the maximum value to the minimum value can be detected. The range can be expanded.

(Second Embodiment)
As shown in FIG. 11, the second embodiment of the present invention is a modification of the first embodiment.

  In the liquid level detection device 200 of the second embodiment, the edge 242 where the plurality of electrodes 240 are mutually spaced is arranged along the radial direction DD of the rotational motion.

  Further, the first contact 266a and the second contact 266b are shifted from each other in the rotational direction DR. Specifically, the first contact 266a and the second contact 266b formed on the free ends 64a-b side of the respective arm portions 260a-b by the two arm portions 260a-b being displaced from each other in the rotational direction DR, It will shift | deviate to the rotation direction DR mutually. That is, if the contact start angle is shifted relative to the electrode 240 to be contacted, the timing is shifted. Therefore, the contact points 266a and 266b may be shifted in the rotation direction.

  Also in the second embodiment, the first contact 266a and the second contact 266b slide with the contact start angle shifted in the rotation direction DR with respect to the electrode 240 to be contacted at a position corresponding to the rotational motion. And since the shift | offset | difference of a contact start angle is in the range of the electrode 240 of contact object, it becomes possible to show | play an effect according to 1st Embodiment.

  Further, according to the second embodiment, the first contact 266a and the second contact 266b are displaced from each other in the rotational direction DR. According to this, it can manufacture easily only by changing arm part 260a-b.

(Third embodiment)
As shown in FIG. 12, the third embodiment of the present invention is a modification of the first embodiment.

  In the liquid level detection device 300 of the third embodiment, the first contact 66a and the second contact 66b are stopped in contact with different electrodes 40 at the rotation ends 338a to 338b where the rotational movement of the rotating body 30 is restricted. To do. That is, it stops in the state shown in FIG. In FIG. 12, the upper stage shows the position of the second contact 66b in the rotational direction DR cross section outside the radial direction DD, and the lower stage shows the position of the first contact 66a in the rotational direction DR cross section inside the radial direction DD. The correspondence relationship of DD is indicated by a one-dot chain line connecting the upper and lower stages. In FIG. 12, the alternate long and short dash line connecting the upper stage and the lower stage also indicates the position of the rotation end 338b in the downward rotation direction DRD.

  Also in the third embodiment, the first contact 66a and the second contact 66b slide with the contact start angle shifted in the rotation direction DR with respect to the electrode 40 to be contacted at a position corresponding to the rotational motion. And since the shift | offset | difference of a contact start angle is in the range of the electrode 40 of contact object, it becomes possible to show | play an effect according to 1st Embodiment.

  Further, according to the third embodiment, the first contact 66a and the second contact 66b are stopped in contact with the different electrodes 40 at the rotation ends 338a-b where the rotational motion of the rotating body 30 is limited. According to this, by avoiding the contact start angle at which each contact 66a-b receives the force in the rotational direction DR received from the electrode 40, the contact point 66a-b smoothly reaches the rotation end 338a or 338b and corresponds to the rotation end 338a-b. The maximum value or the minimum value of the liquid level can be reliably detected.

(Fourth embodiment)
As shown in FIG. 13, the fourth embodiment of the present invention is a modification of the first embodiment.

  In the liquid level detection device 400 according to the fourth embodiment, the second contact 66b disposed outside the first contact 66a in the radial direction DD of the rotational motion is the rotation end 438a-b where the rotational motion of the rotating body 30 is limited. In FIG. 3, the operation stops at the apex portion 46 of the electrode 40. That is, it stops in the state shown in FIG. In FIG. 13, the upper stage shows the position of the second contact 66b in the rotational direction DR cross section outside the radial direction DD, and the lower stage shows the position of the first contact 66a in the rotational direction DR cross section inside the radial direction DD. The correspondence relationship of DD is indicated by a one-dot chain line connecting the upper and lower stages. In FIG. 13, the alternate long and short dash line connecting the upper stage and the lower stage also indicates the position of the rotation end 438b in the downward rotation direction DRD.

  Also in the fourth embodiment, the first contact 66a and the second contact 66b slide with the contact start angle shifted in the rotation direction DR with respect to the electrode 40 to be contacted at a position corresponding to the rotational motion. And since the shift | offset | difference of a contact start angle is in the range of the electrode 40 of contact object, it becomes possible to show | play an effect according to 1st Embodiment.

  Further, according to the fourth embodiment, the second contact 66b disposed on the outer side in the radial direction DD of the rotational motion with respect to the first contact 66a is an electrode at the rotational ends 438a-b where the rotational motion of the rotating body 30 is restricted. It stops at the apex portion 46 of 40. According to this, the second contact 66b having a large influence on the sliding torque N received by the rotating body 30 avoids the contact start angle at which the force in the rotational direction DR received from the electrode 40 is peaked, thereby smoothly rotating the rotating end. It reaches 438a or 438b, and the maximum value or the minimum value of the liquid level corresponding to the rotation ends 438a and 438b can be reliably detected.

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

  Specifically, as a first modification example related to the first to fourth embodiments, as shown in FIG. 14, in the same electrode 40, the contact point between the first contact 66 a and the contact point with the second contact 66 b A step 48 that is shifted in the rotational direction DR may be provided therebetween. In this case, even if the first contact 66a and the second contact 66b are arranged along the radial direction DD, the first contact 66a and the second contact 66b are electrodes to be contacted at positions corresponding to the rotational motion. With respect to 40, it slides by shifting the contact start angle in the rotation direction DR.

  As a second modification regarding the first to fourth embodiments, the deviation between the first contact 66a and the second contact 66b may be other than 1/2 of the pitch PT in the array. For example, the deviation may be 1/2 or less of the pitch PT in the array.

  As a third modification related to the first to fourth embodiments, the difference between the distance L1 and the distance L2 is defined as ΔL, and when the distance L1 is set first, the difference ΔL is set small. According to this, the moment M2 is reduced, and the sliding torque N can be reduced as a whole.

  As a fourth modification related to the first to fourth embodiments, the difference between the distance L1 and the distance L2 is defined as ΔL, and when the distance L2 is set first, the difference ΔL is set large. According to this, the moment M1 is reduced, and the sliding torque N can be reduced as a whole.

  As a fifth modified example related to the first to fourth embodiments, the present invention is applied to a liquid level detecting device in a container such as other fluids mounted on a vehicle, for example, brake fluid, engine cooling water, engine oil and the like. Also good. 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 devices.

  100, 200, 300, 400 Liquid level detection device, 1 Fuel tank (container), 1a Liquid level, 10 Fixed body, 30 Rotating body, 32 Float, 38a-b, 338a-b, 438a-b Rotating end, 40, 240 electrode, 42, 242 edge, 44 convex surface, 46 apex, 60a-b, 260a-b arm, 62a-b fixed end, 64a-b free end, 66a, 266a first contact, 66b, 266b first 2 contacts, PT pitch, DR rotation direction, DRU ascending rotation direction, DRD descending rotation direction, DD radial direction

Claims (9)

A liquid level detection device for detecting a liquid level height of a liquid stored in a container (1),
A fixed body (10) fixed to the container;
A rotating body (30) that performs a rotational movement following the change in the liquid level,
A plurality of electrodes (40, 240) held by the fixed body, arranged in a rotational direction (DR) of the rotational motion, and forming a convex surface portion (44) having a curvature in the rotational direction;
Curved convex first contacts (66a, 266a) and second contacts (66b, 266b) that are electrically connected to each other and pressed against the electrodes to elastically contact the electrodes are formed, and the rotating body And two arm portions (60a-b, 260a-b) that are independently elastically deformable.
The liquid level is detected by an electrical resistance when at least one of the first contact and the second contact is in elastic contact with the electrode,
Each of the arm portions is formed in a leaf spring shape extending from a fixed end (62a-b) connected to the rotating body to a free end (64a-b) along the rotational direction,
The first contact and the second contact are formed on the free end side of each arm part,
The first contact and the second contact slide with respect to the electrode to be contacted at a position corresponding to the rotational movement, with a contact start angle shifted in the rotation direction, and the contact start angle shift is The liquid level detection device is within the range of the electrode to be contacted.   The liquid level detection device according to claim 1, wherein the deviation is ½ of a pitch (PT) in the array. The rotational direction includes an upward rotational direction (DRU) corresponding to the rotational motion following the increase in the liquid level, and a downward rotational direction (DRD) corresponding to the rotational motion following the downward movement.
Each said arm portion, from said fixed end, a liquid according to claim 1 or 2, characterized in that it is formed in the in the rotation direction extends to the free end of the descending rotational direction plate spring Surface detection device.   The said 1st contact and the said 2nd contact stop in the state which contacted the same said electrode in the rotation end (38a-b) where the said rotational motion is restrict | limited, Any one of Claim 1 to 3 characterized by the above-mentioned. The liquid level detection device according to claim 1.   The said 1st contact and the said 2nd contact stop in the state which contacted with the said different electrode in the rotation end (338a-b) where the said rotational motion is restrict | limited, respectively. The liquid level detection device according to claim 1.   The second contact disposed on the outer side in the radial direction (DD) of the rotational movement with respect to the first contact is a vertex (46) of the electrode at a rotational end (438a-b) where the rotational movement is limited. The liquid level detection device according to claim 1, wherein the liquid level detection device is stopped at the point. The first contact (66a) and the second contact (66b) are arranged along the radial direction of the rotational movement,
The liquid level detection device according to any one of claims 1 to 6, wherein an edge (42) in which the plurality of electrodes (40) are spaced from each other is inclined with respect to the radial direction. . The edge (242) where the plurality of electrodes (240) are spaced from each other is disposed along the radial direction of the rotational movement,
The liquid level detection device according to any one of claims 1 to 6, wherein the first contact (266a) and the second contact (266b) are shifted from each other in the rotation direction.   The said rotary body has the float (32) which floats on the liquid level (1a) of the said liquid, and performs the said rotational motion with the buoyancy which arises in the said float, The any one of Claim 1 to 8 characterized by the above-mentioned. The liquid level detection apparatus described in 1.

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