WO2016038815A1

WO2016038815A1 - Liquid surface detection device

Info

Publication number: WO2016038815A1
Application number: PCT/JP2015/004214
Authority: WO
Inventors: 宮川　功
Original assignee: 株式会社デンソー
Priority date: 2014-09-11
Filing date: 2015-08-21
Publication date: 2016-03-17
Also published as: JP6365155B2; JP2016057229A

Abstract

A liquid surface detection device detects the height of the liquid surface (12) of a liquid stored in a container (10) and is provided with a rotating body (50) that rotates so as to follow the liquid surface (12), a shaft part (31b) that is provided on a main body unit (31a) fixed to a container (10) side and supports the rotation of the rotating body (50), a pair of magnet units (52) that are fixed to the rotating body (50) so as to sandwich the shaft part (31b) and generate magnetic flux that penetrates the shaft part (31b), and a Hall element (71) that is disposed inside the shaft part (31b) and generates, through the Hall effect, a voltage corresponding to the magnetic flux from the magnet units (52) accompanying the rotation position of the rotating body (50). The application surface (71a) of the hall element (71) onto which the magnetic flux from the magnet units (52) is applied is set so as to be parallel to the direction of the external magnetic field generated outside the container (10).

Description

Liquid level detector

Cross-reference of related applications

This application is based on Japanese Patent Application No. 2014-185336 filed on September 11, 2014, the contents of which are incorporated herein by reference.

The present disclosure relates to a liquid level detection device that includes a non-contact Hall element and is suitable for use in detecting the liquid level in a fuel tank for a vehicle, for example.

As a conventional liquid level detection device, for example, the one described in Patent Document 1 is known. The liquid level detection device of Patent Document 1 is applied to a fuel tank for a vehicle, and a non-contact Hall element is used. Specifically, a hall element (magnetoelectric conversion element) is built in a shaft portion formed in a body constituting the main body portion of the liquid level detection device. A magnet holder is rotatably supported on the shaft portion. A pair of magnets are fixed to the magnet holder so as to sandwich the shaft portion, that is, the Hall element. Furthermore, the magnet holder is provided with an arm, and a float is connected to the tip of the arm.

In the liquid level detection device of Patent Document 1, the float moves up and down according to the change in the liquid level, and the magnet holder and the magnet rotate accordingly. Then, according to the rotation angle, the magnetic flux amount of the magnet passing through the Hall element changes, and the voltage generated in the Hall element changes (Hall effect). Therefore, in the liquid level detection device of Patent Document 1, the liquid level is detected by a change in voltage generated in the Hall element.

JP 2008-39613 A

Here, various devices are installed on the road surface on which the vehicle travels, and an external magnetic field may be generated from the road surface toward the vehicle by this device. However, in Patent Document 1, no consideration is given to such an external magnetic field from the road surface. If an external magnetic field is generated, an external magnetic field will be applied to the Hall element in addition to the magnetic field generated by the magnet. There is a risk of showing the detection result.

In view of the above, the object of the present disclosure is to provide a liquid level detection device that can suppress the influence of an external magnetic field from a road surface, or can detect a liquid level that is safe for the user. Is to provide.

In the first aspect of the present disclosure, the liquid level detection device detects the height of the liquid level of the liquid stored in the container,
A rotating body that rotates following the liquid level;
A shaft portion that is provided on the main body fixed to the container side and supports the rotation of the rotating body;
A pair of magnet portions that are fixed to the rotating body so as to sandwich the shaft portion and generate magnetic flux penetrating the shaft portion;
A hall element that is arranged inside the shaft part and generates a voltage due to the Hall effect in accordance with the magnetic flux from the magnet part associated with the rotational position of the rotating body,
The application surface to which the magnetic flux from the magnet portion of the Hall element is applied is set to be parallel to the direction of the external magnetic field generated outside the container.

According to this disclosure, the external magnetic field does not act so as to be orthogonal to the application surface of the Hall element, and thus the Hall element can be configured not to detect the external magnetic field. Therefore, the influence by the external magnetic field can be eliminated.

In the second aspect of the present disclosure, the liquid level detection device detects the height of the liquid level of the liquid stored in the container,
A rotating body that rotates following the liquid level;
A shaft portion that is provided on the main body fixed to the container side and supports the rotation of the rotating body;
A pair of magnet portions that are fixed to the rotating body so as to sandwich the shaft portion and generate magnetic flux penetrating the shaft portion;
A hall element that is arranged inside the shaft part and generates a voltage due to the Hall effect in accordance with the magnetic flux from the magnet part associated with the rotational position of the rotating body,
The direction of the orthogonal component perpendicular to the application surface to which the magnetic flux of the Hall element is applied is the same as the direction of the external magnetic field generated outside the container with respect to the magnetic flux generated by the magnet unit when the liquid level becomes the minimum side. It is set to become.

According to this disclosure, when the liquid level is at the minimum side, the magnetic element acts on the Hall element in a form in which the magnetic flux of the external magnetic field is added to the orthogonal component of the magnetic flux by the magnet portion with respect to the application surface. Therefore, as a detection result of the liquid level, the lower liquid level is detected. Therefore, even when there is an external magnetic field, it is possible to detect the liquid level on the safe side for the user.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawing
FIG. 1 is a front view showing a liquid level detection device in the first embodiment, 2 is a cross-sectional view showing a II-II portion in FIG. FIG. 3 is a front view showing the positional relationship between the magnet and the Hall element and the external magnetic field in the first embodiment. FIG. 4 is a graph showing the relationship between the amount of magnetic flux and the output of the Hall IC. FIG. 5 is a graph showing the relationship between the rotation angle of the magnet part and the liquid level in the first embodiment, FIG. 6 is a front view showing the positional relationship between the magnet and the Hall element in the comparative example, and the external magnetic field, FIG. 7 is a side view showing the positional relationship between the magnet and the Hall element in the comparative example, and the external magnetic field, FIG. 8 is a graph showing the relationship between the rotation angle of the magnet part and the liquid level in the comparative example, FIG. 9 is a front view showing the positional relationship between the magnet and the Hall element and the external magnetic field in the second embodiment, FIG. 10 is a graph showing the relationship between the rotation angle of the magnet unit and the liquid level in the second embodiment.

Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each mode, the other modes described above can be applied to the other parts of the configuration. Not only combinations of parts that clearly indicate that the combination is possible in each embodiment, but also a combination of the embodiments even if they are not clearly specified unless there is a problem with the combination. It is also possible.

(First embodiment)
The liquid level detection device 100 according to the first embodiment will be described with reference to FIGS. As shown in FIGS. 1 to 3, the liquid level detection device 100 is installed in a fuel tank 10 for storing vehicle fuel. The fuel tank 10 corresponds to the container of the present disclosure. The liquid level detection device 100 determines the height (liquid level) of the liquid level 12 of the fuel stored in the fuel tank 10 while being held by the fuel pump module 11 installed in the fuel tank 10. It is a device to detect. The liquid level detection device 100 includes a housing 20, a magnet holder 50, a float 60, a Hall IC 70, and the like.

The housing 20 forms the base of the liquid level detection device 100 and includes an inner case 21 and an outer case 31. The housing 20 is provided with three terminals 35a to 35c.

The inner case 21 is formed of a resin material such as polyphenylene sulfide (PPS) resin. The inner case 21 has a flat plate-like portion 21a formed in a flat plate shape, and a columnar portion 21b that protrudes circularly from the flat plate-like portion 21a. An element accommodation chamber 21c that accommodates the Hall IC 70 is provided in the cylindrical portion 21b.

The outer case 31 accommodates the inner case 21 by being formed so as to cover the outer side of the inner case 21. The outer case 31 is formed of a resin material such as PPS resin, like the inner case 21. The outer case 31 protrudes in a cylindrical shape from the outer main body 31a so as to cover the outer main body 31a fixed to the fuel tank 10 (on the container side) via the fuel pump module 11 and the columnar part 21b. And a shaft portion 31b. The outer main body 31a corresponds to the main body of the present disclosure.

The three terminals 35a to 35c are formed in a strip shape from a conductive material such as phosphor bronze. Each of the terminals 35a to 35c is disposed in the flat plate portion 21a and the outer main body portion 31a. Each terminal 35a to 35c is used for transmission of a detection signal such as a voltage in the Hall IC 70 between the Hall IC 70 and an external device (for example, a combination meter).

The magnet holder 50 includes a main body 51, a magnet 52, a yoke 53, a holder cover 54, and the like. The magnet holder 50 corresponds to the rotating body of the present disclosure.

The main body 51 is formed in a flat cylindrical shape by a resin material or the like. The cylindrical first end side in the axial direction is closed by the first wall 51a, and the cylindrical peripheral surface is the second wall 51b. A central hole 51c opened in the axial direction is formed in the central region of the main body.

The main body 51 is arranged so that the second end side (opening side) in the axial direction faces the housing 20, and the shaft portion 31b of the housing 20 is inserted into the center hole 51c. That is, the magnet holder 50 is rotatably supported with respect to the housing 20 by being externally fitted to the shaft portion 31b.

The magnets 52 are each formed in a circular arc shape and are a pair of permanent magnets that form an N pole and an S pole, and are accommodated inside the second wall portion 51 b of the main body portion 51. For example, a ferrite magnet is used as the magnet 52. The magnet 52 corresponds to the magnet unit of the present disclosure. The pair of magnets 52 are provided so that the N pole and the S pole face each other with the shaft portion 31b interposed therebetween by being held by a claw portion formed in the main body portion 51. As described above, the pair of magnets 52 generates the magnetic flux mfM (FIG. 2) that passes through the Hall IC 70 accommodated in the element accommodating chamber 21c from the N pole side toward the S pole side.

The yoke 53 is a flat cylindrical member formed of, for example, an iron material, and is interposed between the second wall portion 51 b and the magnet 52. That is, the yoke 53 is fixed to the inner peripheral surface of the second wall portion 51 b, and the magnet 52 is disposed on the inner peripheral side of the yoke 53. The yoke 53 forms a path for returning the magnetic flux mfM generated from the north pole side to the south pole side of the pair of magnets 52 from the south pole side to the north pole side.

The holder cover 54 has an oval shape in which two short sides bulge outward based on a rectangle, and covers the center hole 51c in the main body 51 so as to cover the outer surface of the first wall 51a. It is a cover to be attached to. The holder cover 54 is formed from a resin material having elasticity. For example, polyacetal resin is used as the resin material.

The float 60 is a floating member made of a material having a specific gravity smaller than that of a fuel such as foamed ebonite. The float 60 can float on the fuel liquid level 12. A float arm 65 is connected to the float 60. The float arm 65 is formed in a round bar shape from a magnetic material such as stainless steel. The first end side of the float arm 65 is inserted through a through hole 61 formed in the float 60. The second end side of the float arm 65 is supported by the magnet holder 50. A portion between the intermediate region of the float arm 65 and the second end side is routed so as to cross the outer surface of the holder cover 54. Therefore, the holder cover 54 is sandwiched between the first wall portion 51 a and the float arm 65.

The magnet holder 50 is rotated relative to the housing 20 integrally with the magnet 52 so as to follow the liquid level 12 by the float 60 and the float arm 65. Here, when the liquid level changes to the maximum side (FULL side), the magnet holder 50 is rotated clockwise in FIG. Therefore, when the liquid level is maximum (when FULL), the pair of magnets 52 has an N pole on the upper right and an S pole on the lower left, as shown in FIG. Conversely, when the liquid level changes to the minimum side (EMPTY side), the magnet holder 50 is rotated counterclockwise in FIG. Therefore, when the liquid level is minimum (EMPTY), the pair of magnets 52 has an N pole on the upper left and an S pole on the lower right as shown in FIG.

In order to deepen understanding in the following description, the rotation angle θ of the magnet holder 50 is defined as follows. That is, as shown in FIG. 3, the vertical downward position of the Hall element 71 is set to a position of 0 ° of the rotation angle θ. Further, a rotation angle that is counterclockwise from the 0 ° position is plus (+ θ), and a rotation angle that is clockwise is minus (−θ). Further, the range that can be taken by the rotation angle θ in the liquid level detection device 100 is a predetermined range that is less than ± 90 °, and this range is a use range (FIG. 5).

The Hall IC 70 is a detection element that detects the relative angle of the magnet holder 50 with respect to the housing 20. The Hall IC 70 includes a Hall element 71 provided in a plate-like IC substrate, three lead wires 72 provided on the Hall element 71, and the like.

The hall element 71 is formed in a flat plate shape and is disposed inside the shaft portion 31 b so as to be sandwiched between the pair of magnets 52. Specifically, the Hall element 71 is accommodated in the element accommodating chamber 21c provided in the cylindrical portion 21b that is inside the shaft portion 31b. As shown in FIG. 3, the plate surfaces (both plate surfaces) of the flat Hall element 71 are application surfaces 71 a to which the magnetic flux mfM from the magnet 52 is applied. Each lead wire 72 extends from the hall element 71 and is connected to each terminal 35a to 35c.

The Hall element 71 (Hall IC 70) is subjected to the action of a magnetic field by the magnet 52 in a state where a voltage is applied, and thereby depends on the density of the magnetic flux mfM passing from one application surface 71a by the Hall effect (that is, proportional). ) Generate voltage. As shown in FIG. 3, the voltage generated by the Hall element 71 changes according to the magnitude of the component orthogonal to the application surface 71 a with respect to the actual magnetic flux mfM generated by the magnet 52. Hereinafter, the magnetic flux component orthogonal to the application surface 71a is defined as an acting magnetic flux mfMv. The voltage generated in the Hall element 71 is output as a signal indicating the detection result via each lead wire 72, each terminal 35a to 35c, and is measured by an external device.

In the present embodiment, the application surface 71a of the Hall element 71 is the following with respect to the shaft portion 31b in a state where the housing 20 (outer body portion 31a) is fixed to the fuel pump module 11 (position defined state). It is arranged like this. That is, the application surface 71a is disposed in the element storage chamber 21c so as to be parallel to a virtual surface including the axial line of the shaft portion 31b and the vertical direction (vertical direction) line. In other words, as shown in FIGS. 1 and 3, the Hall element 71 is disposed such that the application surface 71 a is parallel to the vertical line.

In the liquid level detection device 100 configured as described above, the reciprocating motion of the float 60 that moves up and down following the fuel liquid level 12 is converted into a rotational motion by the float arm 65 held by the magnet holder 50. Are transmitted to these

integral elements

50, 65. Therefore, the magnet holder 50 follows the liquid level of the fuel stored in the fuel tank 10 and rotates relative to the housing 20. Due to the relative rotation of the magnet holder 50, the acting magnetic flux mfMv acting on the Hall element 71 changes, whereby the output voltage V output from the Hall element 71 changes.

Generally, as shown in FIG. 4, the output voltage V of the Hall element 71 is proportional to the amount of magnetic flux. In the present embodiment, as shown in FIG. 5, the output voltage V from the Hall element 71 with respect to the rotation angle θ of the magnet holder 50 is a sin waveform output. In the range of use of the rotation angle θ, the output voltage V with respect to the rotation angle θ has a substantially linear relationship.

The maximum position of the rotation angle θ in the use range is a position when the float 60 moves toward the minimum side of the liquid surface 12 and the magnet holder 50 rotates to the maximum counterclockwise, and is the point E (EMPTY point). ) The output voltage V at the point E displays, for example, an E scale (EMPTY scale) on the display unit (fuel remaining amount meter).

Further, the minimum position of the rotation angle θ in the use range is a position when the float 60 moves toward the maximum side of the liquid surface 12 and the magnet holder 50 rotates to the maximum in the clockwise direction, and the F point (FULL) Point). The output voltage -V at the point F displays, for example, the F scale (FULL scale) on the display unit (fuel remaining amount meter).

Here, the liquid level detection device 100 may be affected by an external magnetic field generated outside the fuel tank 10. The external magnetic field can be generated from, for example, various devices provided on a travel path on which the vehicle travels, and magnetic field generating components. Various devices and magnetic field generating components include, for example, road heaters embedded in roads in cold districts, coils for chargers for non-contact charging of batteries such as electric vehicles and hybrid vehicles, embedded in roads There are equipment for transportation infrastructure and railway lines for trains. As the magnetic flux mfO of the external magnetic field, for example, in the present embodiment, as shown in FIG. 3, it is assumed that the magnetic field goes to the liquid level detection device 100 in the vertical direction from the road surface.

In the present embodiment, as described above, the application surface 71a of the Hall element 71 is parallel to the vertical line. That is, the application surface 71a of the Hall element 71 is parallel to the direction of the external magnetic field. Therefore, the external magnetic field does not act so as to be orthogonal to the application surface 71a of the Hall element 71, so that the Hall element 71 can be configured not to detect the external magnetic field. Therefore, the influence by the external magnetic field can be eliminated.

As a comparative example, as shown in FIGS. 6 and 7, when the application surface 71a of the Hall element 71 is orthogonal to the direction of the external magnetic field, the acting magnetic flux mfMv generated in the Hall element 71 is The direction and the direction of the external magnetic field are aligned on the same line. As shown in FIG. 6, when both directions are opposite, the output voltage V output from the Hall element 71 is subtracted from the original output voltage V by a voltage due to an external magnetic field as shown in FIG. It will be.

In other words, when the rotation angle θ is originally at the point E and the E scale should be displayed, the display shows that the position of the liquid level 12 is shifted to a higher side than the actual level, such as “there is still some fuel”. End up. Therefore, the display for fuel replenishment is delayed for the user, and there is a possibility of causing a gas shortage. In this embodiment, occurrence of such a situation can be prevented.

(Second Embodiment)
A liquid level detection device 100A of the second embodiment is shown in FIG. The second embodiment is different from the first embodiment in that the direction of the application surface 71a of the Hall element 71 is changed, and the magnetic flux mfMv applied by the magnet 52 to the Hall element 71 when the liquid level 12 is at the minimum side. Is the same as the direction of the magnetic flux mfO of the external magnetic field.

Specifically, the application surface 71a of the Hall element 71 is arranged so as to face the horizontal direction with respect to the shaft portion 31b. Further, when the position of the rotation angle θ of 0 ° is the left side position of the hall element 71 in the horizontal direction and the liquid level 12 is at the minimum side, as shown in FIG. The south pole is on the upper right. Therefore, when the magnet holder 50 rotates with the liquid surface 12 facing the minimum side, the magnetic flux mfM by the magnet 52 goes from the region on the generation side of the external magnetic field to the region on the opposite side across the Hall element 71. That is, here, the magnetic flux mfM is directed to the upper right. Therefore, the orthogonal component orthogonal to the application surface 71a, that is, the actual working magnetic flux mfMv with respect to the Hall element 71 is directed upward with respect to the magnetic flux mfM. Therefore, the direction of the acting magnetic flux mfMv is the same as the direction of the magnetic flux mfO of the external magnetic field.

In addition, the position of the float arm 65 is set so that the maximum position and the minimum position of the liquid surface 12 can be obtained based on the position of 0 ° of the rotation angle θ.

In this embodiment, since the direction of the acting magnetic flux mfMv is the same as the direction of the magnetic flux mfO of the external magnetic field, the magnetic flux mfO of the external magnetic field is applied to the working magnetic flux mfMv. Therefore, as shown in FIG. 10, the output voltage V takes a form in which the output voltage V increases (broken line in FIG. 10) when there is no external magnetic field (solid line in FIG. 10). In the present embodiment, the position where the rotation scale θ is at the E point and the E scale should be displayed is a display in which the position of the liquid level 12 is shifted to a lower side than the actual position. Therefore, it is possible to speed up the display for replenishing fuel to the user, and it is possible to avoid a situation where the user runs out of gas.

(Other embodiments)
In the first embodiment, in the state in which the housing 20 (outer body portion 31a) is fixed to the fuel pump module 11 (position-regulated state), the direction of the application surface 71a of the Hall element 71 is set to the shaft portion 31b. By setting them relatively, the application surface 71a was made parallel to the direction of the external magnetic field. However, with respect to the one in which the Hall element 71 is set in a predetermined direction with respect to the shaft portion 31b, the orientation of the housing 20 (outer main body portion 31a) is adjusted and fixed to the fuel pump module 11, thereby applying the application surface. 71a may be parallel to the direction of the external magnetic field.

In each of the above embodiments, the external magnetic field is assumed to be directed from the road surface to the liquid

level detection devices

100 and 100A in the vertical direction, for example. On the other hand, if an external magnetic field directed in the horizontal direction is assumed, the relative positional relationship (structure) of the Hall element 71 and the magnet 52 in each of the above embodiments is rotated by 90 degrees. It becomes possible to respond by setting.

Further, in each of the above embodiments, the liquid level detection device of the present disclosure is applied to one that detects the liquid level 12 of the fuel in the fuel tank 10 for a vehicle. However, the present invention is not limited to this. You may apply to what detects liquid levels, such as oil or ATF for torque converters.

Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

A liquid level detection device for detecting the height of a liquid level (12) of a liquid stored in a container (10),
A rotating body (50) that rotates following the liquid surface (12);
A shaft portion (31b) provided on a main body portion (31a) fixed to the container (10) side and supporting the rotation of the rotating body (50);
A pair of magnet portions (52) that are fixed to the rotating body (50) so as to sandwich the shaft portion (31b) and generate magnetic flux (mfM) that penetrates the shaft portion (31b);
Hall element which is arranged inside the shaft part (31b) and generates a voltage due to the Hall effect according to the magnetic flux (mfM) from the magnet part (52) accompanying the rotational position of the rotating body (50). (71)
The application surface (71a) to which the magnetic flux (mfM) from the magnet part (52) of the Hall element (71) is applied is parallel to the direction of the external magnetic field generated outside the container (10). Liquid level detection device set to.
The direction of the Hall element (71) relative to the shaft portion (31b) is set relatively, so that the application surface (71a) is parallel to the direction of the external magnetic field (mfO). The liquid level detection apparatus described.
The direction of the said main-body part (31a) with respect to the said container (10) is set relatively, The said application surface (71a) is parallel to the direction of the said external magnetic field (mfO). Liquid level detection device.
A liquid level detection device for detecting the height of a liquid level (12) of a liquid stored in a container (10),
A rotating body (50) that rotates following the liquid surface (12);
A shaft portion (31b) provided on a main body portion (31a) fixed to the container (10) side and supporting the rotation of the rotating body (50);
A pair of magnet portions (52) that are fixed to the rotating body (50) so as to sandwich the shaft portion (31b) and generate magnetic flux (mfM) that penetrates the shaft portion (31b);
Hall element which is arranged inside the shaft part (31b) and generates a voltage due to the Hall effect according to the magnetic flux (mfM) from the magnet part (52) accompanying the rotational position of the rotating body (50). (71)
Application surface (mfM) of the Hall element (71) is applied to the magnetic flux (mfM) generated by the magnet part (52) generated when the liquid level (12) is at the minimum side ( 71. The liquid level detection device set so that the direction of the orthogonal component (mfMv) orthogonal to 71a) is the same as the direction of the external magnetic field generated outside the container (10).
The application surface (71a) is orthogonal to the direction of the external magnetic field,
The direction of the magnetic flux (mfM) by the magnet part (52) is set so as to go from the region on the generation side of the external magnetic field to the region on the opposite side across the Hall element (71). The liquid level detection apparatus described in 1.
Mounted on the vehicle,
The liquid level detection device according to any one of claims 1 to 5, wherein the external magnetic field is a magnetic field generated from a device provided on a travel path on which the vehicle travels.