JP2013190395A - Liquid level switch and liquid level detection system having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid level switch by simple structure, which can be used for liquid level detection by operating without depending on power, and a liquid level detection system having the same.SOLUTION: A liquid level switch 30 has: a first light guide member 41; a second light guide member 42 provided with a first end surface 42a oppositely arranged at an interval with a second end surface 41b of the first light guide member 41 so as to continuously guide light guided by the first light guide member 41; a magnet float 47 which is floated on fuel F in a fuel tank 10; and a light regulation magnet 45 which is moved so as to be inserted between the second end surface 41b of the first light guide member 41 and the first end surface 42a of the second light guide member 42 by movement of the magnet float 47.

Description

  The present invention relates to a liquid level switch provided in a fuel tank provided in a vehicle or the like, and a liquid level detection system having the liquid level switch.

  With the recent tightening of exhaust gas regulations, the number of vehicles using liquefied petroleum gas (LPG) or dimethyl ether (DME) instead of gasoline or light oil as a fuel is increasing. In such a fuel tank that stores LPG fuel or DME fuel, the maximum filling amount of fuel filled in the fuel tank for ensuring safety, that is, the upper limit value of the liquid amount in the fuel tank is set. It is prescribed. For example, when the fuel is LPG, the maximum filling amount is 85% of the fuel tank volume. Therefore, for example, Patent Literature 1 proposes a fuel filling system including an overfill prevention mechanism for preventing overfilling exceeding the maximum filling amount.

  A fuel filling system 801 of Patent Document 1 shown in FIG. 19 includes a fuel filling control device 802 for filling a fuel tank 805 provided in a vehicle. The fuel tank 805 is provided with a gas filling pipe 849 that communicates with the inside and outside of the fuel tank 805, and a gas filling pipe 849 disposed outside the fuel tank 805 has a filling nozzle of a fuel filling machine 821 to be described later. A quick coupling 848 capable of attaching and detaching 825 is provided, and an overfilling prevention device 830 is provided at the other end of the gas filling pipe 849 disposed inside the fuel tank 805. The overfill prevention device 830 closes the other end of the gas filling pipe 849 when the fuel in the fuel tank 805 reaches the maximum filling amount, and blocks the inflow of fuel into the fuel tank 805. Further, the fuel tank 805 is provided with a liquid level detection device 806 that detects a predetermined deceleration liquid level height, and the liquid level detection device 806 responds to the detection of the deceleration liquid level height. Outputs a signal containing liquid level information. A barcode 807 is affixed to the outer wall surface of the fuel tank 805, and container information representing a container form is written on the barcode 807.

  The fuel filling control device 802 includes a fuel filling machine 821 as a fuel supply means to which a hose 824 provided with a filling nozzle 825 at the tip is connected, and a filling control device 822 for driving and controlling the fuel filling machine 821. ing. Cables 826 and 827 are connected to the filling control device 822, and a connector 828 attached to the plug 815 of the above-described liquid level detection device 806 is provided at the tip of one cable 826, and the other cable. A barcode reader 829 for reading the barcode 807 described above is provided at the tip of 827. The filling control device 822 acquires the liquid level information and the container information via the cables 826 and 827, and detects the filling amount of the fuel filled in the fuel tank 805 based on these information. Based on this filling amount, the supply speed of the fuel supplied from the fuel filling machine 821 to the fuel tank 805 is controlled. As a result, the water hammer effect at the time of fuel supply speed change can be reduced and the filling time can be shortened.

JP 2009-138755 A

  However, in the fuel filling system 801 described above, since the liquid level can be detected even when the main power source of the vehicle is in the off state (ignition off state), the liquid level detecting circuit 851 provided in the vehicle is always powered. Since it must be connected to a standby power supply that can be supplied, there is a problem that power is supplied to the liquid level detection circuit 851 even when fuel is not supplied, and power is consumed unnecessarily. Further, since the liquid level detection circuit 851 is operated by electric power, it is necessary to have a configuration with an explosion-proof measure in order to use it for flammable fuel and the like, and there is a problem that the configuration becomes complicated. It was.

  The present invention aims to solve this problem. That is, an object of the present invention is to provide a liquid level switch having a simple configuration that can be used for liquid level detection by operating without depending on electric power, and a liquid level detection system having the switch.

  In order to achieve the above object, an invention described in claim 1 is a liquid level switch used for detecting a liquid level of a liquid in a liquid tank, and is guided by a first light guide member and the first light guide member. A second light guide member provided with a light incident surface disposed opposite to the light output surface of the first light guide member so as to continuously guide the emitted light; and in the liquid tank And a moving wall portion that is moved so as to be inserted between the light exit surface and the light incident surface by the movement of the float portion. Liquid level switch.

  The invention described in claim 2 is the invention described in claim 1, wherein one of the float part and the moving wall part has a magnetic force generating means, the other has a magnetic material, and the moving wall. The part is arranged in a space isolated from the liquid tank and is configured to be moved by a magnetic force generated between the part and the float part.

  The invention described in claim 3 is the invention described in claim 1 or 2, wherein the float portion is inserted between the light exit surface and the light entrance surface so that the movable wall portion is inserted between the light exit surface and the light entrance surface. The moving wall portion is configured to move at a predetermined rate with respect to a change in the liquid level of the liquid level tank.

  The invention described in claim 4 is the invention described in any one of claims 1 to 3, wherein at least one of the light exit surface of the first light guide member and the light entrance surface of the second light guide member. One surface is provided with a wavelength filter configured by arranging a plurality of filter portions that transmit light of different wavelengths in the moving direction of the moving wall portion.

  In order to achieve the above object, the invention described in claim 5 is a liquid level switch used for detecting a liquid level in a liquid tank. The light absorbing member disposed opposite to the one end surface of the light guide member, the float portion floated on the liquid in the liquid tank, and the one end surface of the light guide member by the movement of the float portion A moving wall portion that is moved so as to be inserted between the light absorbing member and the light guiding member when the moving wall portion is between one end surface of the light guiding member and the light absorbing member. And a light reflecting member provided on the moving wall so as to face the end face.

  In order to achieve the above object, the invention described in claim 6 is a liquid level detection system for detecting a liquid level in a liquid tank, wherein the incident light is in a state corresponding to the liquid level in the liquid tank. A liquid level switch that emits light; and a liquid level detection unit that detects light on the basis of the state of light emitted from the liquid level switch while entering light into the liquid level switch; A liquid level detection system, characterized in that the switch is constituted by the liquid level switch according to any one of claims 1 to 5.

  According to the first aspect of the present invention, the first light guide member and the light output surface of the first light guide member so as to continuously guide the light guided by the first light guide member. And a second light guide member provided with a light incident surface disposed opposite to each other, a float part floated on the liquid in the liquid tank, and a light exit surface of the first light guide member by movement of the float part Since the movable wall portion is moved so as to be inserted between the light incident surface of the second light guide member, the float portion is moved according to the liquid level of the liquid tank, The moving wall portion is inserted between the light exit surface of the first light guide member and the light entrance surface of the second light guide member. Therefore, depending on the insertion state of the moving wall portion, the first light guide member and the second light guide member are inserted. The state of the guided light can be changed. Therefore, the liquid is operated based on the change in the light state by operating to change the state of the light guided to the first light guide member and the second light guide member according to the liquid level regardless of the electric power. It can be used for position detection. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

  According to the second aspect of the present invention, at least one of the float part and the moving wall part has the magnetic force generating means, the other has the magnetic material, and the moving wall part is isolated from the liquid tank. Since the liquid in the liquid tank and the moving wall are separated from each other, for example, the liquid is moved in the liquid tank. Problems due to contact with the liquid in the liquid tank, such as wall sticking, can be suppressed.

  According to the third aspect of the present invention, the liquid level is such that the float portion is inserted between the light exit surface of the first light guide member and the light entrance surface of the second light guide member. Since the moving wall portion is configured to move at a predetermined rate with respect to the change in the liquid level of the tank, the state of the light guided to the first light guide member and the second light guide member is changed to the liquid in the liquid tank. It can be changed according to the change of the position, and can be used for detailed liquid level detection.

  According to the fourth aspect of the present invention, the plurality of filters that allow light of different wavelengths to pass through at least one of the light exit surface of the first light guide member and the light entrance surface of the second light guide member. Since the wavelength filter configured by arranging the portions in the moving direction of the moving wall portion is provided, the wavelength of the light guided to the first light guide member and the second light guide member according to the insertion degree of the moving wall portion (that is, , The light state) can be changed, and therefore, the light wavelength is changed according to a plurality of liquid levels, for example, compared with a configuration in which the light state is changed to a binary state (present or absent). Thus, it can be used for detailed liquid level detection. In addition, when the wavelength of light is used for detecting the liquid level, it is not easily affected by light attenuation or the like. For example, the intensity (luminance) of light traveling in the light guide member depending on the degree of insertion of the moving member between the light guide members. The accuracy of liquid level detection can be improved by detecting the wavelength of light, as compared with a configuration in which () is changed.

  According to the fifth aspect of the invention, one light guide member capable of guiding light in both directions, a light absorbing member disposed opposite to one end face of the light guide member, and a liquid A float part floated on the liquid in the tank, a moving wall part that is moved so as to be inserted between one end face of the light guide member and the light absorbing member by the movement of the float part, and the moving wall part is guided And a light reflecting member provided on the moving wall so as to face the one end surface of the light guide member when between the one end surface of the light member and the light absorbing member. By moving the float portion according to the liquid level, when the moving wall portion is between the one end face of the light guide member and the light absorbing member, the light emitted from the one end face of the light guide member is The light is reflected by the light reflecting member, is incident on the one end face, is guided in the reverse direction, and is transferred. When the wall portion is not between the one end face of the light guide member and the light absorbing member, the light emitted from the one end face of the light guide member is absorbed by the light absorbing member and is not incident on the one end face. Therefore, it is possible to change the state of the light guided back and forth to the light guide member according to the insertion state of the moving wall portion. Therefore, it operates so as to change the state of the light guided to the light guide member according to the liquid level regardless of the electric power, and can be used for the liquid level detection based on the change of the light state. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved. Moreover, since there is one light guide member, the size can be reduced.

  According to the invention described in claim 6, since the liquid level switch is configured by the liquid level switch according to any one of claims 1 to 5, according to the liquid level without depending on the electric power. The liquid level can be detected based on the change in the light state by operating to change the state of the light guided to the light guide member. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

It is sectional drawing which shows one Embodiment (Embodiment 1) of the liquid level switch of this invention, Comprising: (a) is a figure which shows the state which has the light control magnet with which a liquid level switch is provided in an allowable position, (b) ) Is a diagram showing a state in a restricted position. It is sectional drawing which shows other embodiment (Embodiment 2) of the liquid level switch of this invention. It is a front view of the optical filter member with which the liquid level switch of FIG. 2 is provided. It is sectional drawing which shows the state which has the light control magnet with which the liquid level switch of FIG. 2 is in an allowable position. It is sectional drawing which shows the state which has the light control magnet with which the liquid level switch of FIG. 2 is located in an intermediate position. It is sectional drawing which shows the state which has the light control magnet with which the liquid level switch of FIG. 2 is in a control position. It is sectional drawing which shows other embodiment (Embodiment 3) of the liquid level switch of this invention, Comprising: It is a figure which shows the state which has the light control magnet with which a liquid level switch is provided in an allowable position. It is sectional drawing which shows the state which the light control magnet with which the liquid level switch of FIG. 7 is located in the position of 30% of the distance between the said permissible position and a control position from a permissible position. It is sectional drawing which shows the state which the light control magnet with which the liquid level switch of FIG. 7 is located in the position of 60% of the distance between the said permissible position and a control position from a permissible position. It is sectional drawing which shows the state which has the light control magnet with which the liquid level switch of FIG. 7 is in a control position. It is a front view of the optical filter member with which the liquid level switch of FIG. 7 is provided. It is sectional drawing which shows other embodiment (Embodiment 4) of the liquid level switch of this invention, (a) is a figure which shows the state which has the light control magnet with which a liquid level switch is provided in an allowable position, b) is a figure which shows the state in a control position. It is a schematic block diagram of one Embodiment (Embodiment 5) of the fuel filling system of this invention. It is a figure explaining the connection relation of each component of the fuel filling system of FIG. (A) is a schematic block diagram of the light reception unit of the fuel filling system of FIG. 14, (b) is a figure which shows the output waveform in each part of a light reception unit. It is a flowchart which shows an example of the process (supply speed control process) which concerns on this invention which CPU of MPU of the fuel supply control apparatus of FIG. 14 performs. It is a figure explaining the connection relation of each component in other embodiment (Embodiment 6) of the liquid level detection system of this invention. It is a figure which shows the structure of the modification of the liquid level switch of FIG. It is a figure which shows the structure of the conventional fuel filling system.

(Embodiment 1)
Hereinafter, a liquid level switch showing an embodiment of the present invention will be described with reference to FIG.

  The liquid level switch 30 of this embodiment is attached to the fuel tank 10 of the vehicle and used for detecting the liquid level of the liquid fuel in the fuel tank 10, for example. The liquid level of the fuel in the fuel tank 10 is related to the liquid level in the fuel tank 10, and the liquid level can be detected by using the liquid level.

  The fuel tank 10 to which the liquid level switch 30 is attached is formed in a substantially box shape using a material having corrosion resistance for the fuel F accommodated therein, such as a metal material such as stainless steel. The part 10b is provided with an opening 10c that allows the inside and the outside of the fuel tank 10 to communicate with each other. The liquid level switch 30 is attached to the opening 10c of the fuel tank 10 so as to close the opening 10c.

  As shown in FIGS. 1A and 1B, the liquid level switch 30 includes a case 31, a pair of optical cable attachment portions 38 and 39, a first light guide member 41, a second light guide member 42, It has an upper support member 43, a lower support member 44, a light restricting magnet 45 as a moving wall portion, and a magnet float 47 as a float portion.

  The liquid level switch 30 (1) When the liquid level of the fuel F in the fuel tank 10 is less than a predetermined supply speed deceleration liquid level Ls, one of the pair of optical cable mounting portions 38, 39 is one optical cable mounting portion 38. (2) When the liquid level of the fuel F in the fuel tank 10 is equal to or higher than a predetermined supply speed decelerating liquid level Ls, the one optical cable mounting part 38 It is configured so that the light incident on is not emitted from the other optical cable mounting portion 39.

  The case 31 has a bottomed cylindrical case main body 32 and a case lid 36 attached to the case main body 32. The case main body 32 and the case lid 36 are made of a material having corrosion resistance with respect to the fuel F supplied to the fuel tank 10 such as a metal material such as stainless steel.

  The case main body 32 includes a cylindrical peripheral wall portion 32a, a bottom wall portion 32b provided so as to close the lower end portion of the peripheral wall portion 32a, a flange portion 32c provided at the periphery of the upper end portion of the peripheral wall portion 32a, and a peripheral wall. A partition wall portion 32d that partitions the inner space of the portion 32a in the axial direction S (vertical direction in FIG. 1), and these are integrally formed.

  In the case main body 32, an upper space 33 and a lower space 34 which are cut off from each other by the partition wall portion 32d are provided. A plurality of communication holes 35 that communicate the lower space 34 and the outside of the case body 32 are provided in a portion surrounding the lower space 34 in the peripheral wall portion 32 a and the bottom wall portion 32 b. Thereby, when the liquid level switch 30 is attached to the fuel tank 10, the lower space 34 is communicated with the space in the fuel tank 10, and the upper space 33 is isolated from the space in the fuel tank 10.

  The outer diameter of the peripheral wall 32a of the case body 32 is formed smaller than the diameter of the opening 10c of the fuel tank 10, and the outer diameter of the flange 32c is formed larger than the diameter of the opening 10c. Thus, the case 31 is inserted into the opening 10c of the fuel tank 10 from the bottom wall portion 32b side of the case 31, and the peripheral wall portion 32a and the bottom wall portion 32b are positioned in the fuel tank 10, and the flange portion 32c The fuel tank 10 is attached so as to close the opening 10c.

  The case lid 36 is formed in a disc shape having substantially the same diameter as the inner diameter of the peripheral wall portion 32a of the case main body 32, and is attached to the case main body 32 so as to close the upper end portion of the peripheral wall portion 32a. When the case lid 36 is attached to the case body 32, the upper space 33 in the case body 32 is sealed.

  The pair of optical cable attachment portions 38 and 39 is an optical connector to which an optical cable is attached. The pair of optical cable attachment portions 38 and 39 are disposed through the case lid 36.

  One optical cable attachment portion 38 connects between the optical cable and a first light guide member 41 described later so as to guide light from the optical cable attached thereto to the first light guide member 41 described later.

  The other optical cable attachment portion 39 connects between the optical cable and a second light guide member 42 described later so as to guide light from the second light guide member 42 described later to the optical cable attached thereto.

  The first light guide member 41 is formed in a substantially L-shaped prism shape using a light-transmitting material such as quartz glass or acrylic resin, and the L-shaped long side tip is tapered. A first end surface 41a (a surface facing upward in FIG. 1) formed in a plan view is provided, and a second end surface 41b (left in FIG. 1) having a square shape in plan view is provided at the tip of the L-shaped short side. And a reflection surface 41c that reflects the light incident on the first end surface 41a toward the second end surface 41b.

  The second light guide member 42 is formed in a substantially L-shaped prismatic shape using the same material as that of the first light guide member 41, and the first portion having a square shape in plan view is formed on the tip portion on the short side of the L shape. An end surface 42a (a surface facing right in FIG. 1) is provided, and an L-shaped long side tip is formed in a tapered shape, and is a second end surface 42b (a surface facing upward in FIG. 1) having a circular shape in plan view. ), And a reflection surface 42c that reflects light incident on the first end surface 42a toward the second end surface 42b is provided at the L-shaped corner.

  The first light guide member 41 and the second light guide member 42 are sandwiched and fixed vertically by an upper support member 43 and a lower support member 44 disposed in the upper space 33 of the case 31. The first end face 41 a of the first light guide member 41 is connected to one optical cable attachment portion 38, and the second end face 42 b of the second light guide member 42 is connected to the other optical cable attachment portion 39. In addition, the second end surface 41b (that is, the light exit surface) of the first light guide member 41 and the first end surface 42a (that is, the light incident surface) of the second light guide member 42 are disposed to face each other with a space therebetween. .

  The first light guide member 41 guides the light incident on the first end surface 41a to exit from the second end surface 41b, and the second light guide member 42 transmits the light incident on the first end surface 42a. The light is guided so as to be emitted from the second end face 42b. And since the 2nd end surface 41b of the 1st light guide member 41 and the 1st end surface 42a of the 2nd light guide member 42 are opposingly arranged at intervals, the 2nd end surface 41b of the 1st light guide member 41 is arranged. The light emitted from the light enters the first end face 42 a of the second light guide member 42. That is, the second light guide member 42 is spaced from the second end surface 41b (light exit surface) of the first light guide member 41 so that the light guided by the first light guide member 41 is continuously guided. A first end surface 42a (light incident surface) is provided so as to be opposed to each other.

  For example, a ferrite magnet is used as the light restricting magnet 45 and is formed in a cubic shape. That is, the light regulating magnet 45 itself is a magnetic force generating means, and is also a magnetic body. The light regulating magnet 45 is formed so that the size of one surface is a square that is slightly larger than the second end surface 41 b of the first light guide member 41. The light restricting magnet 45 is provided in a magnet moving space 46 formed by the upper support member 43, the lower support member 44, the second end surface 41 b of the first light guide member 41, and the first end surface 42 a of the second light guide member 42. The N pole and the S pole are accommodated in the axial direction S. The magnet moving space 46 is formed in a square columnar space that is substantially the same as the shape in which the two light restricting magnets 45 are stacked in the axial direction S so that the light restricting magnet 45 can only move in the axial direction S. .

  When the light restricting magnet 45 is located near the lower support member 44 shown in FIG. 1A (specifically, in the lower support member 44, that is, the allowable position P1), the second end face of the first light guide member 41 is provided. The light is allowed to travel in the magnet moving space 46 from 41b toward the first end face 42a of the second light guide member 42, and is positioned closer to the upper support member 43 shown in FIG. When located at a position between the second end surface 41b of the light guide member 41 and the first end surface 42a of the second light guide member 42, that is, the restriction position P2, the second end surface 41b of the first light guide member 41 is (2) The progress of light in the magnet moving space 46 toward the first end surface 42a of the light guide member 42 is restricted (blocked).

  The magnet float 47 is made of, for example, a molding material in which a magnetic material such as ferrite is mixed with a resin material such as polyethylene, and is formed into a cylindrical shape including bubbles inside so as to float on the fuel F. The magnetic poles are provided so that the N pole and the S pole are aligned in the axial direction. That is, the magnet float 47 itself is a magnetic force generating means, and is also a magnetic body. Of course, the magnet float 47 may have a configuration in which a magnet is embedded in a foamed resin material such as foamed nitrile rubber, in addition to such a configuration. The magnet float 47 is formed so that its diameter is slightly smaller than the diameter of the lower space 34 of the case body 32 so that it can move in the axial direction S within the lower space 34. The magnet float 47 is accommodated in the lower space 34 so that the same magnetic pole as the magnetic pole facing the lower space 34 of the light restricting magnet 45 is coaxial with the case body 32 and faces the upper space 33.

  In the liquid level switch 30, the light regulating magnet 45 is disposed in the upper space 33 (specifically, in the magnet moving space 46), and the magnet float 47 is disposed in the lower space 34 that is disconnected (isolated) from the upper space 33. The light regulating magnet 45 and the magnet float 47 are magnetic poles having the same polarity so that repulsive forces act on each other across the partition wall portion 32d (in this embodiment, the S poles are ) Are facing each other.

  Next, an operation (action) according to the present invention in the above-described liquid level switch 30 will be described with reference to FIGS.

  As shown in FIG. 1A, when the liquid level of the fuel F in the fuel tank 10 is low and there is no fuel F in the lower space 34 of the case 31, the magnet float 47 is positioned on the bottom wall portion 32b. Yes. At this time, since the light restricting magnet 45 is in the allowable position P1, the light emitted from the second end surface 41b of the first light guide member 41 passes through the magnet moving space 46 to the first end surface 42a of the second light guide member 42. Light can enter.

  When the liquid level of the fuel F in the fuel tank 10 rises and the fuel F flows into the lower space 34 from the communication hole 35, the magnet float 47 floats on the fuel F and reaches the liquid level of the fuel F in the fuel tank 10. Moved accordingly.

  As shown in FIG. 1B, when the liquid level of the fuel F in the fuel tank 10 reaches a predetermined supply speed deceleration liquid level Ls, the magnet float 47 has a position where the upper surface thereof abuts against the partition wall portion 32d. Moved to. At this time, the light restricting magnet 45 is moved to the restricting position P <b> 2 by the magnetic force with the magnet float 47, so that the light emitted from the second end surface 41 b of the first light guide member 41 is applied to the light restricting magnet 45. As a result, the light cannot enter the first end surface 42a of the second light guide member 42.

  Thereby, in the liquid level switch 30, when the liquid level of the fuel F in the fuel tank 10 is less than the supply speed deceleration liquid level Ls, the light is incident on the first light guide member 41 through the one optical cable attachment portion 38. The light is continuously guided to the first light guide member 41 and the second light guide member 42 and emitted from the second light guide member 42 to the outside through the other optical cable attachment portion 38.

  Further, when the liquid level of the fuel F in the fuel tank 10 reaches the supply speed deceleration liquid level Ls, the light incident on the first light guide member 41 through the one optical cable mounting portion 38 is the first light guide member. Although the light is guided to 41, it is blocked by the light restricting magnet 45, and is not continuously guided by the second light guide member 42, and is not emitted from the second light guide member 42 to the outside through the other optical cable mounting portion 38. .

  Accordingly, by using the liquid level switch 30 and entering light from one optical cable attachment portion 38 and determining the state of light emitted from the other optical cable attachment portion 38 (presence or absence of light), the fuel tank 10 The liquid level of the fuel F inside can be detected.

  As described above, according to this embodiment, the first light guide member 41 and the light guided by the first light guide member 41 are continuously guided so as to guide the first light guide member 41. A second light guide member 42 provided with a first end surface 42a (light incident surface) disposed opposite to the two end surfaces 41b (light-emitting surface) with a gap therebetween, and a magnet float 47 floated on the fuel F in the fuel tank 10 And the light regulating magnet 45 moved so as to be inserted between the second end surface 41b of the first light guide member 41 and the first end surface 42a of the second light guide member 42 by the movement of the magnet float 47, Therefore, when the magnet float 47 is moved according to the liquid level of the fuel tank 10, the light restricting magnet 45 moves between the second end surface 41 b of the first light guide member 41 and the second light guide member 42. Inserted between first end face 42a Are, therefore, it is possible to change the state of the light is guided to the first light guide member 41 and the second light guide member 42 by the insertion state into between the light regulating magnets 45. Therefore, it operates so as to change the state of the light guided to the first light guide member 41 and the second light guide member 42 according to the liquid level regardless of the electric power, and based on the change of the light state. It can be used for liquid level detection. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

  Further, each of the magnet float 47 and the light regulating magnet 45 is composed of a magnet (magnetic force generating means, magnetic body), and the light regulating magnet 45 is disposed in the upper space 33 isolated from the fuel tank 10. And is moved by the magnetic force generated between the magnet float 47 and the fuel in the fuel tank 10 and the light restricting magnet are separated, for example, the light restricting magnet is fixed. It is possible to suppress problems caused by coming into contact with the fuel in the fuel tank.

  In the above-described embodiment, the light regulating magnet 45 is disposed in the upper space 33 isolated from the fuel tank 10, but the present invention is not limited to this. For example, instead of the light restricting magnet 45 and the magnet float 47, the light restricting member made of a non-translucent synthetic resin formed in the same shape as the light restricting magnet 45 and the same shape as the magnet float 47 are formed. A through-hole is provided at a location corresponding to the magnet movement space 46 in the partition wall portion 32d, and the light regulating member and the float are integrally moved by the connecting member through the through-hole. It is good also as a structure connected so that possible. In such a configuration, since the light regulating member and the float are connected to each other, it is not necessary to configure them with a member that generates a magnetic force. Even in such a configuration, the float is moved according to the liquid level of the fuel tank 10, so that the light regulating member becomes the second end surface 41 b of the first light guide member 41 and the first end surface of the second light guide member 42. Therefore, the state of the light guided to the first light guide member 41 and the second light guide member 42 can be changed depending on the insertion state of the light regulating member between them.

(Embodiment 2)
Hereinafter, the liquid level switch which shows other embodiment of this invention is demonstrated with reference to FIGS.

  As shown in FIG. 2, the liquid level switch 30 </ b> A includes a case 31, a pair of optical cable attachment portions 38 and 39, a first light guide member 41, a second light guide member 42, an upper support member 43, It has a support member 44, a light regulating magnet 45 as a moving wall portion, a magnet float 47 as a float portion, and an optical filter member 80 as a wavelength filter.

  Since the present embodiment is the same as the first embodiment except that the optical filter member 80 is newly added to the configuration of the first embodiment described above, the same parts as those of the first embodiment are denoted by the same reference numerals. Description is omitted.

  The liquid level switch 30A (1) When the liquid level of the fuel F in the fuel tank 10 is less than a predetermined first supply speed deceleration liquid level Ls1, one of the pair of optical cable mounting portions 38, 39 is attached to one optical cable. Red light and blue light included in the light incident on the part 38 are emitted from the other optical cable attachment part 39, and (2) the fuel level in the fuel tank 10 is equal to or higher than the first supply speed deceleration liquid level Ls1. And when it is less than a predetermined second supply speed deceleration liquid level Ls2 higher than the first supply speed deceleration liquid level Ls1, only the blue light contained in the light incident on one optical cable mounting portion 38 is used for the other optical cable. (3) When the liquid level of the fuel F in the fuel tank 10 is equal to or higher than a predetermined second supply speed decelerating liquid level Ls2, the light incident on one optical cable mounting part 38 is emitted from the mounting part 39. Optical cable attachment Not Idemitsu 9 is configured as.

  As shown in FIG. 3, the optical filter member 80 is formed in a film shape having the same shape as the first end surface 42 a of the second light guide member 42, and the optical filter member 80 is divided in half. A blue transmission filter portion 81 that transmits only blue light is provided in this portion, and a red transmission filter portion 82 that transmits only red light is provided in the other portion. The optical filter member 80 has a blue transmission filter portion 81 on the upper side and a red transmission filter portion 82 on the lower side, and the blue transmission filter portion 81 and the red transmission filter portion 82 are aligned in the axial direction S. 2 The light guide member 42 is provided on the first end surface 42a so as to be densely stacked.

  Next, the operation (action) according to the present invention in the above-described liquid level switch 30A will be described with reference to FIGS.

  As shown in FIG. 4, when the liquid level of the fuel F in the fuel tank 10 is low and there is no fuel F in the lower space 34 of the case 31, the magnet float 47 is located on the bottom wall portion 32b. At this time, since the light restricting magnet 45 is at the permissible position P1, all of the light emitted from the second end face 41b of the first light guide member 41 reaches the optical filter member 80 through the magnet moving space 46, and the light The light passes through the blue transmission filter portion 81 and the red transmission filter portion 82 of the filter member 80 and can enter the first end face 42 a of the second light guide member 42.

  When the liquid level of the fuel F in the fuel tank 10 rises and the fuel F flows into the lower space 34 from the communication hole 35, the magnet float 47 floats on the fuel F and reaches the liquid level of the fuel F in the fuel tank 10. Moved accordingly.

  Then, as shown in FIG. 5, when the liquid level of the fuel F in the fuel tank 10 reaches a predetermined first supply speed deceleration liquid level Ls1, the magnet float 47 has its upper surface approaching the partition wall 32d. Moved. At this time, the light restricting magnet 45 is moved to the intermediate position P3 between the allowable position P1 and the restricting position P2 by the magnetic force with the magnet float 47, and therefore the second end face 41b of the first light guide member 41. Of the light emitted from the light, the lower half light is blocked by the light restricting magnet 45 and cannot enter the first end surface 42 a of the second light guide member 42, and the upper half light passes through the magnet moving space 46. It reaches the optical filter member 80, passes through the blue transmission filter portion 81 of the optical filter member 80, and can enter the first end face 42 a of the second light guide member 42.

  Then, as shown in FIG. 6, when the liquid level of the fuel F in the fuel tank 10 reaches a predetermined second supply speed deceleration liquid level Ls2, the magnet float 47 reaches a position where the upper surface of the magnet float 47 abuts against the partition wall portion 32d. Moved. At this time, since the light restricting magnet 45 is moved to the restricting position P2 by the magnetic force between the magnet float 47, all of the light emitted from the second end face 41b of the first light guide member 41 is the light restricting magnet. The light is blocked by 45 so that light cannot enter the first end face 42 a of the second light guide member 42.

  Thereby, in the liquid level switch 30A, when the liquid level of the fuel F in the fuel tank 10 is less than the first supply speed deceleration liquid level Ls1, the light enters the first light guide member 41 through the one optical cable attachment portion 38. The blue light and the red light included in the light are selected by the optical filter member 80 and are sequentially guided to the first light guide member 41 and the second light guide member 42, so that the second light guide Blue light and red light are emitted from the member 42 to the outside through the other optical cable mounting portion 38.

  Further, when the liquid level of the fuel F in the fuel tank 10 is equal to or higher than the first supply speed deceleration liquid level Ls1 and less than the second supply speed deceleration liquid level Ls2, the first light guide member 41 is passed through one optical cable attachment portion 38. The light that has entered the first light guide member 41 and the second light guide member 42 are selected by the optical filter member 80, and only the blue light included in the light is selected. Only the blue light is emitted from the optical member 42 through the other optical cable attachment portion 38 to the outside.

  Further, when the liquid level of the fuel F in the fuel tank 10 becomes equal to or higher than the second supply speed deceleration liquid level Ls2, the light incident on the first light guide member 41 through the one optical cable attachment portion 38 is the first light. Although the light is guided to the light guide member 41, it is blocked by the light restricting magnet 45 and is not continuously guided by the second light guide member 42, and is externally passed from the second light guide member 42 through the other optical cable mounting portion 38. Is not emitted.

  Therefore, using the liquid level switch 30A, light is incident from one optical cable mounting portion 38 and light is emitted from the other optical cable mounting portion 38 (red light and blue light / blue light only / no light). Can determine the liquid level of the fuel F in the fuel tank 10 in a plurality of stages.

  As described above, according to this embodiment, the first light guide member 41 and the light guided by the first light guide member 41 are continuously guided so as to guide the first light guide member 41. A second light guide member 42 provided with a first end surface 42a (light incident surface) disposed opposite to the two end surfaces 41b (light-emitting surface) with a gap therebetween, and a magnet float 47 floated on the fuel F in the fuel tank 10 And the light regulating magnet 45 moved so as to be inserted between the second end surface 41b of the first light guide member 41 and the first end surface 42a of the second light guide member 42 by the movement of the magnet float 47, Therefore, when the magnet float 47 is moved according to the liquid level of the fuel tank 10, the light restricting magnet 45 moves between the second end surface 41 b of the first light guide member 41 and the second light guide member 42. Inserted between first end face 42a Are, therefore, it is possible to change the state of the light is guided to the first light guide member 41 and the second light guide member 42 by the insertion state into between the light regulating magnets 45. Therefore, it operates so as to change the state of the light guided to the first light guide member 41 and the second light guide member 42 according to the liquid level regardless of the electric power, and based on the change of the light state. It can be used for liquid level detection. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

  Further, each of the magnet float 47 and the light regulating magnet 45 is composed of a magnet (magnetic force generating means, magnetic body), and the light regulating magnet 45 is disposed in the upper space 33 isolated from the fuel tank 10. And is moved by the magnetic force generated between the magnet float 47 and the fuel in the fuel tank 10 and the light restricting magnet are separated, for example, the light restricting magnet is fixed. It is possible to suppress problems caused by coming into contact with the fuel in the fuel tank.

  Further, on the first end face 42a (light incident surface) of the second light guide member 42, a blue transmission filter portion 81 and a red transmission filter portion 82 that transmit light of different colors (that is, wavelengths) are arranged in the axial direction S ( In other words, since the optical filter member 80 arranged side by side in the movement direction of the light restricting magnet 45 is provided, the second end face 41b of the first light guide member 41 of the light restricting magnet 45 and the second light guide member 42 are arranged. The color (that is, the wavelength) of the light guided to the first light guide member 41 and the second light guide member 42 can be changed according to the degree of insertion between the first end surface 42a, and therefore, in a plurality of stages. Compared with a configuration in which the light wavelength is changed in accordance with the liquid level, for example, the light state is changed to a binary state (present or absent), it can be used for detailed liquid level detection. In addition, if the wavelength of light is used for liquid level detection, it is less susceptible to light attenuation and the like, for example, the degree of insertion of the light regulating magnet 45 between the first light guide member 41 and the second light guide member 42. Therefore, the liquid level detection accuracy can be improved as compared with a configuration in which the state (luminance) of light traveling in the light guide member is changed.

  In the above-described embodiment, the optical filter member 80 is provided on the first end surface 42a (light incident surface) of the second light guide member 42, but is not limited thereto. For example, the optical filter member 80 may be provided on the second end surface 41 b (light exit surface) of the first light guide member 41, or the first end surface 42 a of the second light guide member 42 and the first end surface of the first light guide member 41. It may be provided on both of the two end faces 41b, and provided on at least one of the first end face 42a of the second light guide member 42 and the second end face 41b of the first light guide member 41, as long as it is not contrary to the object of the present invention. It only has to be done.

(Embodiment 3)
Hereinafter, the liquid level switch which shows other embodiment of this invention is demonstrated with reference to FIGS.

  As shown in FIGS. 7 to 10, the liquid level switch 30 </ b> B includes a case 31, a pair of optical cable attachment portions 38 and 39, a first light guide member 41, a second light guide member 42, and an upper support member 43. A lower support member 44, a light regulating magnet 45 as a moving wall portion, an optical filter member 85 as a wavelength filter, a magnet float 90 as a float portion, and a spring 95 as a biasing member. ing.

  The present embodiment is the same as the first embodiment except that the optical filter member 85 and the spring 95 are newly added to the configuration of the first embodiment described above, and the magnet float 90 is used instead of the magnet float 47. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The liquid level switch 30B has a wavelength selected according to the liquid level of the fuel F in the fuel tank 10 out of the light incident on one of the pair of optical cable mounting portions 38 and 39. Light is emitted from the other optical cable mounting portion 39.

  In the present embodiment, the liquid level of the fuel F in the fuel tank 10 changes in the liquid level range U from the empty liquid level L0 to the full liquid level Lm. The air amount liquid level L0 is not in a state where the fuel tank 10 is completely empty, but in a state where some fuel F is contained.

  As shown in FIG. 11, the optical filter member 85 is formed in a film shape having the same shape as the first end surface 42 a of the second light guide member 42 as viewed from above, and as it goes from one end 85 a to the other end 85 b. The wavelength of light that can be transmitted is gradually increased. In other words, the optical filter member 85 is provided with a plurality of filter portions that transmit light of different wavelengths arranged in order so that the wavelength of light that can be transmitted from the one end 85a toward the other end 85b gradually increases. It has been. The optical filter member 85 has one end 85a on the upper side and the other end 85b on the lower side so that the one end 85a and the other end 85b are aligned in the axial direction S. Are densely stacked.

  In the optical filter member 85, the wavelength (wavelength range) of light that can pass through the optical filter member 85 changes according to the shielded ratio. In the present embodiment, the optical filter member 85 is configured to transmit light having a wavelength of 400 nm to 500 nm. For example, when 20% of the optical filter member 85 is shielded from the other end 85b side of the optical filter member 85, the wavelength range of light that can be transmitted is reduced by 20%, and light having a wavelength of 400 nm to 480 nm can be transmitted. When 40% is shielded, the wavelength range of light that can be transmitted is narrowed by 40%, and light with a wavelength of 400 nm to 460 nm can be transmitted. That is, the wavelength of light that can be transmitted according to the shielded ratio. The range is narrowed.

  As shown in FIG. 7 and the like, the magnet float 90 is made of a molding material in which a magnetic material such as ferrite is mixed with a resin material such as polyethylene, and has a cylindrical shape including bubbles inside so as to float on the fuel F. After the formation, the first portion 91 provided with magnetic poles so that the N pole and the S pole are aligned in the axial direction by the magnetization process, and a resin material such as polyethylene, for example, are floated on the fuel F. And a second portion 92 that is coaxially and integrally attached to the lower surface 91a of the first portion 91. The second portion 92 is formed in a cylindrical shape having a smaller diameter than the first portion 91. That is, the 1st part 91 is a magnetic force generation means and is also a magnetic body. The magnet float 90 is formed so that the diameter of the first portion 91 is slightly smaller than the diameter of the lower space 34 of the case body 32 so that the magnet float 90 can move in the axial direction S within the lower space 34. The magnet float 90 is accommodated in the lower space 34 coaxially with the case body 32 with the first portion 91 facing upward and the second portion 92 facing downward. Further, the first portion 91 is arranged such that the same magnetic pole as the magnetic pole facing the lower space 34 in the light restricting magnet 45 faces the upper space 33.

  Further, the magnet float 90 is accommodated in the lower space 34 so as to receive buoyancy in the liquid level range U of the fuel F in the fuel tank 10 (that is, the empty liquid level L0 to the full liquid level Lm).

  The spring 95 is a coil spring wound in a cylindrical shape whose outer diameter is substantially the same as the diameter of the lower space 34. The spring 95 is housed in the lower space 34 together with the magnet float 90, the second portion 92 of the magnet float 90 is inserted inside the spring 95, and the upper end thereof is in contact with the lower surface 91 a of the first portion 91 of the magnet float 90. The lower end of the casing 31 is disposed so as to be in contact with the bottom wall 32b of the case 31. The spring 95 biases the magnet float 90 upward or biases the magnet float 90 downward depending on the position of the magnet float 90. Specifically, when the buoyancy of the magnet float 90 and the weight of the magnet float 90 and the magnetic force (downward force) applied to the magnet float 90 are balanced, the spring 95 is in a neutral state in which no urging force is generated. When the downward force is larger, the spring 95 is compressed from the neutral state. Therefore, an urging force is generated to push up the magnet float 90. When the downward force is smaller than the buoyancy, the spring 95 is in the neutral state. Since it is in a more extended state, an urging force is generated so as to lower the magnet float 90.

  Here, the relationship between the biasing force of the spring 95, the buoyancy of the magnet float 90, the weight of the magnet float 90, and the magnetic force applied to the magnet float 90 will be described.

  The initial state is when the liquid level of the fuel F in the fuel tank 10 is the empty liquid level L0. The weight of the light regulating magnet 45 is w, the weight of the magnet float 90 is W, the spring constant of the spring 95 is k, the amount of displacement of the spring 95 in the initial state is a, and the liquid level of the fuel F (displacement from the initial state) X), y is the amount of displacement from the initial state of the magnet float 90, f is the magnetic force between the light restricting magnet 45 and the magnet float 90, and h is the buoyancy applied to the magnet float 90.

  Further, it is assumed that the weight w and the magnetic force f of the light restricting magnet 45 are balanced in the initial state. By doing so, the displacement amount (movement amount) of the light restricting magnet 45 becomes the same as the movement amount of the magnet float 90.

Since the buoyancy h applied to the magnet float 90 is related to the height of the float below the liquid level in the magnet float 90,
h = α (xy) (1)
(Α: constant)
Represented as:

A weight W and a magnetic force f are applied downward to the magnet float 90, and an urging force of a spring and a buoyancy h are applied upward. Since these are balanced, the relational expression of the force applied to the magnet float 90 Is
W + f = k (a−y) + α (xy) (2)
Represented as:

Since the liquid level x is 0 and the displacement amount y of the magnet float 47 is 0 in the initial state, from the above equation (2),
W + f = ka (3)
Is obtained.

From these equations (2) and (3), y = (α / (k + α)) x (4)
Is obtained.

  Therefore, in the above equation (4), by appropriately selecting k, the range of displacement of the magnet float 90 can be made smaller than the range of the fuel F liquid level change (ie, the liquid level range U). For example, when the height of the fuel F from the empty liquid level L0 to the full liquid level Lm is 150 mm, k is selected so that (α / (k + α)) in the above equation (4) is 0.1. By doing so, the displacement y of the magnet float 90 when the liquid level x changes from the empty liquid level L0 to the full liquid level Lm (that is, 150 mm) can be set to 15 mm.

  Then, by making the displacement range of the magnet float 90 the same as the distance between the allowable position P1 and the restricting position P2 of the light restricting magnet 45, the displacement of the magnet float 90, that is, the liquid level of the fuel F is determined. In response to the change, the light regulating magnet 45 can be moved within the moving range at a predetermined rate (specifically, the same rate as the rate from the empty liquid level L0 to the current liquid level with respect to the liquid level range U). . As a result, the light restricting magnet 45 is moved at a predetermined rate so as to be inserted between the second end surface 41 b of the first light guide member 41 and the first end surface 42 a of the second light guide member 42. The state of light (wavelength of light) guided to the light guide member 41 and the second light guide member 42 can be changed over the liquid level range U of the fuel F in the fuel tank 10.

  Next, the operation (action) according to the present invention in the above-described liquid level switch 30B will be described with reference to FIGS.

  As shown in FIG. 7, when the fuel F is in the empty liquid level L0 in the fuel tank 10, the magnet float 90 is at the farthest position from the partition wall 32d. At this time, since the light restricting magnet 45 is in the allowable position P1, all of the light emitted from the second end surface 41b of the first light guide member 41 reaches the optical filter member 85 through the magnet moving space 46, and the light Light having a wavelength of 400 nm to 500 nm transmitted through the filter member 85 can enter the first end face 42 a of the second light guide member 42.

  When the liquid level of the fuel F in the fuel tank 10 rises and the fuel F flows into the lower space 34 from the communication hole 35, the magnet float 90 floats on the fuel F, and the liquid of the fuel F in the fuel tank 10. It moves according to the place.

  Then, as shown in FIG. 8, when the liquid level of the fuel F in the fuel tank 10 reaches a liquid level that is 30% higher than the liquid level range L0 from the liquid level L0, the upper surface 91b of the magnet float 90 is It moves so that it may approach the partition wall part 32d. At this time, the light restricting magnet 45 is moved from the allowable position P1 to a position 30% above the distance between the allowable position P1 and the restricting position P2 by the magnetic force with the magnet float 90. Of the light emitted from the second end surface 41b of the light guide member 41, the light on the lower side 30% is blocked by the light restricting magnet 45 and cannot enter the first end surface 42a of the second light guide member 42, The upper 70% of the light reaches the optical filter member 85 through the magnet moving space 46, and the optical filter member 85 has a wavelength of 400 nm to 470 nm (that is, 70% from the shorter wavelength of the light selected by the optical filter member 85). Light) is transmitted through a portion for selecting the wavelength of light, and can enter the first end face 42 a of the second light guide member 42.

  As shown in FIG. 9, when the liquid level of the fuel F in the fuel tank 10 reaches a liquid level that is 60% higher than the liquid level range L0 from the empty liquid level L0, the upper surface 91b of the magnet float 90 is Furthermore, it moves so that it may approach the partition wall part 32d. At this time, the light restricting magnet 45 is moved from the permissible position P1 to a position 60% above the distance between the permissible position P1 and the restrictive position P2 due to the magnetic force with the magnet float 90. Out of the light emitted from the second end surface 41b of the light guide member 41, light on the lower side 60% is blocked by the light restricting magnet 45 and cannot enter the first end surface 42a of the second light guide member 42, The upper 40% of the light reaches the optical filter member 85 through the magnet moving space 46, and is 40 nm to 440 nm of the optical filter member 85 (that is, 40% of the light selected by the optical filter member 85 from the shorter wavelength). Light) is transmitted through a portion for selecting the wavelength of light, and can enter the first end face 42 a of the second light guide member 42.

  As shown in FIG. 10, when the liquid level of the fuel F in the fuel tank 10 reaches the full liquid level Lm, the magnet float 47 is moved to a position where the upper surface thereof abuts against the partition wall portion 32d. At this time, the light restricting magnet 45 is moved to the restricting position P <b> 2 by the magnetic force with the magnet float 47, so that the light emitted from the second end surface 41 b of the first light guide member 41 is applied to the light restricting magnet 45. As a result, the light cannot enter the first end surface 42a of the second light guide member 42.

  Thereby, in the liquid level switch 30B, when the liquid level of the fuel F in the fuel tank 10 is the empty liquid level L0, the light incident on the first light guide member 41 through the one optical cable attachment portion 38 is Light having a wavelength of 400 nm to 500 nm included in the light is selected by the optical filter member 85 and continuously guided to the first light guide member 41 and the second light guide member 42, and then from the second light guide member 42. The light selected through the other optical cable attachment portion 38 is emitted to the outside.

  Further, until the current liquid level of the fuel F in the fuel tank 10 reaches the full liquid level Lm, the light incident on the first light guide member 41 through the one optical cable mounting portion 38 is included in the light. Light having a wavelength corresponding to the liquid level of the fuel F is selected by the optical filter member 85 from light having a wavelength of 400 nm to 500 nm, and is continuously guided to the first light guide member 41 and the second light guide member 42. Thus, the selected light is emitted from the second light guide member 42 through the other optical cable attachment portion 38 to the outside.

  Further, when the liquid level of the fuel F in the fuel tank 10 becomes equal to or higher than the full liquid level Lm, the light incident on the first light guide member 41 through the one optical cable mounting portion 38 is the first light guide member. Although the light is guided to 41, it is blocked by the light restricting magnet 45, and is not continuously guided by the second light guide member 42, and is not emitted from the second light guide member 42 to the outside through the other optical cable mounting portion 38. .

  Therefore, the liquid level switch 30B is used to enter the light from one optical cable attachment portion 38 and determine the state of light emitted from the other optical cable attachment portion 38 (that is, the wavelength of light / no light). Thus, the liquid level of the fuel F in the fuel tank 10 can be detected in a plurality of stages.

  As described above, according to this embodiment, the first light guide member 41 and the light guided by the first light guide member 41 are continuously guided so as to guide the first light guide member 41. A second light guide member 42 provided with a first end surface 42a (light incident surface) disposed opposite to the two end surfaces 41b (light-emitting surface) with a gap therebetween, and a magnet float 47 floated on the fuel F in the fuel tank 10 And the light regulating magnet 45 moved so as to be inserted between the second end surface 41b of the first light guide member 41 and the first end surface 42a of the second light guide member 42 by the movement of the magnet float 47, Therefore, when the magnet float 47 is moved according to the liquid level of the fuel tank 10, the light restricting magnet 45 moves between the second end surface 41 b of the first light guide member 41 and the second light guide member 42. Inserted between first end face 42a Are, therefore, it is possible to change the state of the light is guided to the first light guide member 41 and the second light guide member 42 by the insertion state into between the light regulating magnets 45. Therefore, it operates so as to change the state of the light guided to the first light guide member 41 and the second light guide member 42 according to the liquid level regardless of the electric power, and based on the change of the light state. It can be used for liquid level detection. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

  Further, each of the magnet float 47 and the light regulating magnet 45 is composed of a magnet (magnetic force generating means, magnetic body), and the light regulating magnet 45 is disposed in the upper space 33 isolated from the fuel tank 10. And is moved by the magnetic force generated between the magnet float 47 and the fuel in the fuel tank 10 and the light restricting magnet are separated, for example, the light restricting magnet is fixed. It is possible to suppress problems caused by coming into contact with the fuel in the fuel tank.

  Further, the fuel in the fuel tank 10 is such that the magnet float 90 inserts the light regulating magnet 45 between the second end surface 41 b of the first light guide member 41 and the first end surface 42 a of the second light guide member 42. Since the light regulating magnet 45 is moved at a predetermined rate with respect to the change in the liquid level of F, the state of the light guided to the first light guide member 41 and the second light guide member 42 is determined as fuel. It can be changed according to the change of the liquid level of the fuel F in the tank 10, and can be used for detailed liquid level detection.

  In addition, a plurality of filter portions that transmit light of different wavelengths are provided on the first end surface 42a (light incident surface) of the second light guide member 42 from the one end 85a toward the other end 85b (that is, in the axial direction S). 2) Since the optical filter member 85 arranged in order so that the wavelength of light that can be transmitted is gradually increased is provided, the second end face 41b of the first light guide member 41 of the light regulating magnet 45 and the second The wavelength of light guided to the first light guide member 41 and the second light guide member 42 can be changed according to the degree of insertion between the light guide member 42 and the first end surface 42a. Compared with a configuration in which the light wavelength is changed in accordance with the liquid level, for example, the light state is changed to a binary state (present or absent), it can be used for detailed liquid level detection. In addition, if the wavelength of light is used for liquid level detection, it is less susceptible to light attenuation and the like, for example, the degree of insertion of the light regulating magnet 45 between the first light guide member 41 and the second light guide member 42. Therefore, the liquid level detection accuracy can be improved as compared with a configuration in which the state (luminance) of light traveling in the light guide member is changed.

  In the above-described embodiment, the optical filter member 85 is provided on the first end surface 42a (light incident surface) of the second light guide member 42. However, the present invention is not limited to this. For example, the optical filter member 85 may be provided on the second end surface 41 b (light exit surface) of the first light guide member 41, or the first end surface 42 a of the second light guide member 42 and the first end surface of the first light guide member 41. It may be provided on both of the two end faces 41b, and provided on at least one of the first end face 42a of the second light guide member 42 and the second end face 41b of the first light guide member 41, as long as it is not contrary to the object of the present invention. It only has to be done.

(Embodiment 4)
Hereinafter, a liquid level switch showing another embodiment of the present invention will be described with reference to FIG.

  As shown in FIGS. 12A and 12B, the liquid level switch 30C includes a case 131, an optical cable mounting portion 138, a light guide member 141, an upper support member 143, a lower support member 144, and a moving wall. A light regulating magnet 145 as a part and a magnet float 147 as a float part.

  The liquid level switch 30C (1) folds back the light incident on the optical cable attachment portion 138 when the liquid level of the fuel F in the fuel tank 10 is less than a predetermined supply speed deceleration liquid level Ls. Light emitted from the optical cable attachment portion 138, (2) When the liquid level of the fuel F in the fuel tank 10 is equal to or higher than the predetermined supply speed deceleration liquid level Ls, the light incident on the optical cable attachment portion 138 is absorbed internally. Thus, the optical cable attachment portion 138 is configured not to emit light.

  The case 131 has a bottomed cylindrical case main body 132 and a case lid 136 attached to the case main body 132. The case main body 132 and the case lid 136 are made of a material having corrosion resistance with respect to the fuel F supplied to the fuel tank 10 such as a metal material such as stainless steel.

  The case main body 132 includes a cylindrical peripheral wall portion 132a, a bottom wall portion 132b provided so as to close the lower end portion of the peripheral wall portion 132a, a flange portion 132c provided at the periphery of the upper end portion of the peripheral wall portion 132a, and a peripheral wall. A partition wall portion 132d that partitions the inner space of the portion 132a in the axial direction S (vertical direction in FIG. 12), and these are integrally formed.

  In the case main body 132, an upper space 133 and a lower space 134 that are cut off from each other by the partition wall 132d are provided. A plurality of communication holes 135 are provided in the portion surrounding the lower space 134 in the peripheral wall portion 132a and the bottom wall portion 132b to communicate the lower space 134 with the outside of the case body 132. Thus, when the liquid level switch 30C is attached to the fuel tank 10, the lower space 134 is communicated with the space in the fuel tank 10, and the upper space 133 is isolated from the space in the fuel tank 10.

  The outer diameter of the peripheral wall 132a of the case body 132 is formed smaller than the diameter of the opening 10c of the fuel tank 10, and the outer diameter of the flange 132c is formed larger than the diameter of the opening 10c. Accordingly, the case 131 is inserted into the opening 10c of the fuel tank 10 from the bottom wall portion 132b side of the case 131, and the peripheral wall portion 132a and the bottom wall portion 132b are positioned in the fuel tank 10, and the flange portion 132c The fuel tank 10 is attached so as to close the opening 10c.

  The case lid 136 is formed in a disc shape having substantially the same diameter as the inner diameter of the peripheral wall portion 132a of the case main body 132, and is attached to the case main body 132 so as to close the upper end portion of the peripheral wall portion 132a. When the case lid 136 is attached to the case body 132, the upper space 133 in the case body 132 is sealed.

  The optical cable attachment portion 138 is an optical connector to which an optical cable is attached. The optical cable attachment portion 138 is disposed through the case lid 136.

  The optical cable attachment portion 138 guides light from the optical cable attached thereto to a light guide member 141 described later, and guides the light from the light guide member 141 to the optical cable attached thereto, and the optical cable and the light guide member 141. Is connected.

  The light guide member 141 is formed in a substantially L-shaped prismatic shape using a light-transmitting material such as quartz glass or acrylic resin, and the L-shaped long side tip is tapered. A first end surface 141a (a surface facing upward in FIG. 12) having a circular shape in plan view is formed, and a second end surface 141b having a square shape in plan view (on the left side in FIG. And a reflection surface 141c that reflects the light incident on the first end surface 141a toward the second end surface 141b.

  The light guide member 141 is sandwiched and fixed vertically between an upper support member 143 and a lower support member 144 disposed in the upper space 133 of the case 131. The first end surface 141 a of the light guide member 141 is connected to the optical cable attachment portion 138. Further, the second end surface 141b of the light guide member 141 is disposed so as to be opposed to a light absorbing member 150, which will be described later. The second end surface 141b corresponds to one end surface in the claims.

  The light guide member 141 guides the light incident on the first end surface 141a to be emitted from the second end surface 141b, and guides the light incident on the second end surface 141b to be emitted from the first end surface 141a. Shine. That is, the light guide member 141 guides light in both directions.

  The light absorbing member 150 is made of, for example, a synthetic resin, and one surface thereof is a flat surface, and the other surface is a curved surface that closely overlaps the inner peripheral surface of the upper space 133, and the length thereof is the upper space. This is a plate-like member having a length substantially the same as the axial length of 133 and a width substantially the same as the width of a light regulating magnet 145 described later. The light absorbing member 150 is coated on one surface with a material that absorbs light, such as carbon black. The light absorbing member 150 is arranged so that the length direction thereof is parallel to the axial direction S, and one surface thereof is opposed to the second end surface 141b of the light guide member 141 with a space therebetween.

  The light reflecting member 160 is, for example, a plate-like member having a mirror surface process such as plating or polishing on one surface using a synthetic resin, a metal material, or the like. The light reflecting member 160 is formed so that the shape in plan view is the same as that of a light regulating magnet 145 described later. The light reflecting member 160 is configured to reflect the light incident on one surface thereof without being substantially attenuated. The light reflecting member 160 is provided in a light regulating magnet 145 described later.

  For example, a ferrite magnet or the like is used as the light regulating magnet 145 and is formed in a cubic shape. That is, the light regulating magnet 145 itself is a magnetic force generating means and is also a magnetic body. The light regulating magnet 145 has an N pole and an S pole in the magnet moving space 146 formed by the upper support member 143, the lower support member 144, the second end surface 141 b of the light guide member 141, and the light absorbing member 150. They are accommodated in the direction S. The magnet moving space 146 is formed in a square columnar space that is substantially the same as the shape in which the two light restricting magnets 145 are stacked in the axial direction S so that the light restricting magnet 145 can move only in the axial direction S. .

  The light reflecting member 160 is fixed to the surface of the light restricting magnet 145 facing the second end surface 141b of the light guide member 141 with the mirror-finished surface facing outward.

  When the light restricting magnet 145 is at a position close to the lower support member 144 shown in FIG. 12A (a position between the second end surface 141b of the light guide member 141 and the light absorbing member 150, that is, an allowable position Q1). The second end surface 141b of the light guide member 141 and the light reflecting member 160 face each other, and the light emitted from the second end surface 141b is reflected by the light reflecting member 160 and is incident on the second end surface 141b.

  Further, when the light restricting magnet 145 is at a position close to the upper support member 143 shown in FIG. 12B (a position between the upper support member 143 and the light absorbing member 150, that is, the restricting position Q2), the light restricting magnet 145 is guided. The second end surface 141b of the member 141 and the light absorbing member 150 face each other, and the light emitted from the second end surface 141b is absorbed by the light absorbing member 150 and is not incident on the second end surface 141b.

  The magnet float 147 is made of, for example, a molding material in which a magnetic material such as ferrite is mixed with a resin material such as polyethylene, and is formed into a cylindrical shape including bubbles inside so as to float on the fuel F. The magnetic poles are provided so that the N pole and the S pole are aligned in the axial direction. That is, the magnet float 147 itself is a magnetic force generating means and is also a magnetic body. The magnet float 147 is formed so that its diameter is slightly smaller than the diameter of the lower space 134 of the case main body 132 so that it can move in the axial direction S within the lower space 134. The magnet float 147 is accommodated in the lower space 134 so that the same magnetic pole as the magnetic pole facing the lower space 134 in the light restricting magnet 145 is directed to the upper space 133 and coaxial with the case main body 132.

  In the liquid level switch 30C, the light regulating magnet 145 is disposed in the upper space 133 (specifically, in the magnet moving space 146), and the magnet float 147 is disposed in the lower space 134 that is disconnected from the upper space 133. In addition, the light regulating magnet 145 and the magnet float 147 are opposed to each other with the same poles (in this embodiment, the S poles) so that repulsive forces act on each other across the partition wall 132d. Has been.

  Next, the operation (action) according to the present invention in the above-described liquid level switch 30C will be described with reference to FIGS. 12 (a) and 12 (b).

  As shown in FIG. 12A, when the liquid level of the fuel F in the fuel tank 10 is low and there is no fuel F in the lower space 134 of the case 131, the magnet float 147 is positioned on the bottom wall portion 132b. Yes. At this time, since the light restricting magnet 145 is at the allowable position Q1, the light emitted from the second end surface 141b of the light guide member 141 is reflected by the light reflecting member 160 and can enter the second end surface 141b. .

  When the liquid level of the fuel F in the fuel tank 10 rises and the fuel F flows into the lower space 134 from the communication hole 135, the magnet float 147 floats on the fuel F and reaches the liquid level of the fuel F in the fuel tank 10. Moved accordingly.

  Then, as shown in FIG. 12 (b), when the liquid level of the fuel F in the fuel tank 10 reaches a predetermined supply speed deceleration liquid level Ls, the magnet float 147 has a position where the upper surface thereof abuts against the partition wall 132d. Moved to. At this time, the light restricting magnet 145 is moved to the restricting position Q2 by the magnetic force with the magnet float 147, so that the light emitted from the second end surface 141b of the light guide member 141 is absorbed by the light absorbing member 150. Thus, it becomes impossible to enter the second end surface 141b.

  Thereby, in the liquid level switch 30C, when the liquid level of the fuel F in the fuel tank 10 is less than the supply speed deceleration liquid level Ls, the light incident on the light guide member 141 through the optical cable mounting portion 138 is guided. The light is reciprocated in the optical member 141 and guided to the outside through the optical cable attaching portion 138.

  Further, when the liquid level of the fuel F in the fuel tank 10 reaches the supply speed deceleration liquid level Ls, the light incident on the light guide member 141 through the optical cable mounting portion 138 is guided to the light guide member 141. However, the light is absorbed by the light absorbing member 150 and is not guided back and forth within the light guide member 141, and is not emitted from the light guide member 141 to the outside through the optical cable attachment portion 138.

  Therefore, by using the liquid level switch 30C, light is incident from the optical cable attachment portion 138, and the state of the light emitted from the optical cable attachment portion 138 (the presence or absence of light) is determined, whereby the fuel in the fuel tank 10 is determined. The liquid level of F can be detected.

  As described above, according to the present embodiment, the light guide member 141, the light absorbing member 150 disposed opposite to the second end surface 141 b (one end surface) of the light guide member 141, and the fuel tank 10 A magnet float 147 floated on the fuel F, a light regulating magnet 145 moved so as to be inserted between the second end surface 141b of the light guide member 141 and the light absorbing member 150 by the movement of the magnet float 147, and light Light provided on the light restriction magnet 145 so as to face the second end surface 141b of the light guide member 141 when the restriction magnet 145 is between the second end surface 141b of the light guide member 141 and the light absorbing member 150. The reflection member 160, and the magnet float 147 is moved in accordance with the liquid level of the fuel tank 10, so that the light regulating magnet is moved. When the light 145 is between the second end surface 141b of the light guide member 141 and the light absorbing member 150, the light emitted from the second end surface 141b of the light guide member 141 is reflected by the light reflecting member 160. When the light is incident on the second end surface 141b and guided in the reverse direction of the light guide member 141, and the light regulating magnet 145 is not between the second end surface 141b of the light guide member 141 and the light absorbing member 150. The light emitted from the second end surface 141b of the light guide member 141 is absorbed by the light absorbing member 150 and disappears without entering the second end surface 141b. Therefore, the second end surface 141b of the light regulating magnet 145 is lost. The state of light guided back and forth to the light guide member 141 (the presence or absence of light) can be changed according to the insertion state between the light absorbing member 150 and the light absorbing member 150. Therefore, it operates so as to change the state of the light guided to the light guide member 141 according to the liquid level regardless of the electric power, and can be used for the liquid level detection based on the change of the light state. . In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved. Moreover, since the number of the light guide member 141 is one compared with the above-mentioned Embodiment 1-3 provided with two light guide members, it can reduce in size.

  Further, each of the magnet float 147 and the light regulating magnet 145 is composed of a magnet (magnetic force generating means, magnetic body), and the light regulating magnet 145 is disposed in an upper space 133 isolated from the fuel tank 10. And is moved by the magnetic force generated between the magnet float 147 and the fuel in the fuel tank 10 and the light restricting magnet are separated, for example, the light restricting magnet is fixed. It is possible to suppress problems caused by coming into contact with the fuel in the fuel tank.

(Embodiment 5)
Hereinafter, a fuel filling system which is an embodiment of the liquid level detection system of the present invention will be described with reference to FIGS.

  This fuel filling system is a system that fills a fuel tank mounted on a vehicle with liquefied petroleum gas (LPG) fuel. When a user performs an automatic filling operation, fuel filling starts and fuel in the fuel tank is filled. When the liquid level reaches a predetermined supply speed decelerating liquid level Ls, the fuel supply speed to the fuel tank is gradually decreased, and the supply speed is reduced to 0 before reaching the maximum filling liquid level Lm of the fuel tank. That is, the fuel supply is stopped. Thereafter, the user supplies fuel by manual filling operation and fills up to the maximum filling liquid level Lm. The maximum filling liquid level Lm and the supply speed decelerating liquid level Ls are appropriately set according to the type of fuel, the configuration of the fuel tank, the configuration of the system, etc. In this embodiment, when the maximum filling liquid level Lm is reached, the fuel tank Is set to 85% of the fuel tank volume. Further, the filling amount of the fuel tank is set to 70% of the filling amount (that is, the maximum filling amount) at the maximum filling liquid level Lm at the supply speed deceleration liquid level Ls.

  As shown in FIGS. 13 and 14, the fuel filling system 1 includes a liquid amount measuring device 20 disposed in a fuel tank 10 mounted on a vehicle, a fuel supply device 50, and fuel supply as a liquid level detection means. And a control device 60.

  Both the fuel supply device 50 and the fuel supply control device 60 are accommodated in a casing 70 provided with a filling hose 71. The filling hose 71 accommodates a fuel supply pipe 72 inside thereof, and a filling nozzle 73 is provided at the tip thereof.

  The fuel tank 10 is formed in a substantially box shape, and the side wall 10a is provided with a filling port 11 for filling the fuel F therein. The filling port 11 is provided with a quick coupling 12, and a filling nozzle 73 provided at the tip of a filling hose 71 extending from the housing 70 can be easily attached or detached. Since the fuel tank 10 is formed in a substantially box shape, the amount of liquid in the fuel tank 10 is proportional to the liquid level (liquid level). Of course, the shape of the fuel tank 10 is arbitrary, and even in this case, the amount of liquid in the fuel tank 10 and the liquid level are related.

  The fuel tank 10 is provided with a fuel filling pipe 13. One end of the fuel filling pipe 13 is disposed in the filling port 11, and the other end is disposed in the fuel tank 10. The other end of the fuel filling pipe 13 is provided with an overfill prevention device (not shown) similar to the above-described conventional fuel filling system, and this device prevents filling of the fuel F exceeding the maximum filling liquid level Lm. doing. One end of the fuel filling pipe 13 is connected to the fuel supply pipe 72 and communicated with each other when the filling nozzle 73 is attached to the filling port 11.

  Further, the upper wall portion 10 b of the fuel tank 10 is provided with an opening portion 10 c that communicates the inside and the outside of the fuel tank 10. A liquid level switch 30 described later is attached to the opening 10c of the fuel tank 10 so as to close the opening 10c.

  The liquid amount measuring device 20 includes a pair of fuel tank side optical cables 21 and 22 arranged in the fuel tank 10, an optical connector socket 23 provided in the filling port 11 of the fuel tank 10, and a liquid level in the fuel tank 10. The above-described liquid level switch 30 for measuring the height is included.

  The pair of fuel tank-side optical cables 21 and 22 are well-known optical cables that include an optical fiber and a protective coating (sheath) that covers the periphery of the optical fiber and guides light incident on one end to the other end. The pair of fuel tank side optical cables 21 and 22 are routed on the outer surface of the fuel tank 10.

  One end 21 a of one fuel tank side optical cable 21 is connected to an optical connector socket 23 provided in the filling port 11 of the fuel tank 10, and the other end 21 b is connected to one optical cable attachment portion 38 of the liquid level switch 30. It is connected. The one fuel tank side optical cable 21 is provided so as to guide the light incident on one end 21a on the optical connector socket 23 side to one optical cable attachment portion 38 connected to the other end 21b.

  One end 22 a of the other fuel tank side optical cable 22 is connected to the optical connector socket 23, and the other end 22 b is connected to the other optical cable attachment portion 39 of the liquid level switch 30. The other fuel tank side optical cable 22 is provided so as to guide the light incident on the other end 22b from the other optical cable attachment portion 39 to the one end 22a on the optical connector socket 23 side.

  The liquid level switch 30 has the configuration of the first embodiment described above. Instead of the liquid level switch 30, the liquid level switch 30A of the second embodiment and the liquid level switch 30B of the third embodiment described above may be used. In this case, the configuration of the fuel supply control device 60 described later is changed in accordance with each liquid level switch.

  In the liquid quantity measuring device 20, one fuel tank side optical cable 21, one optical cable attachment portion 38, a first light guide member 41, a magnet moving space 46, a second light guide member 42, the other optical cable attachment portion 39, and The other fuel tank side optical cable 22 constitutes one optical path portion 48. This optical path portion 48 uses the light incident on one end 21a (hereinafter also referred to as “inlet end 21a”) of one fuel tank side optical cable 21 as an inlet end to the other fuel tank side optical cable as an outlet end. 22 is configured to be led to one end 22a (hereinafter also referred to as "exit end 22a").

  The fuel supply device 50 is configured by, for example, a pump that sucks up liquid, and is a device that sucks up fuel F from a fuel storage tank (not shown) provided in the ground and supplies the fuel F to the fuel tank 10. The fuel supply device 50 is connected to the fuel supply pipe 72 of the filling hose 71, and flows the fuel F sucked up from the fuel storage tank into the fuel supply pipe 72 at a specified supply speed. The fuel supply device 50 is electrically connected to a fuel supply control device 60 described later, and the supply speed of the fuel F is controlled by a control signal from the fuel supply control device 60.

  The fuel supply control device 60 includes a pair of control device side optical cables 61 and 62 arranged in the filling hose 71, an optical connector plug 63 provided in the filling nozzle 73 of the filling hose 71, a light emitting unit 64, and a light receiving unit. A unit 65 and a supply speed controller 66 are provided.

  The pair of control device side optical cables 61 and 62 are well-known optical cables that include an optical fiber and a protective coating (sheath) that covers the periphery of the optical fiber, and guides the light incident on one end to the other end. The pair of fuel tank side optical cables 21, 22 are routed in the filling hose 71.

  One end 61a of one control device side optical cable 61 is connected to an optical connector plug 63 provided in the filling nozzle 73 of the filling hose 71, and the other end 61b is connected to a light emitting unit 64 described later. The one control device side optical cable 61 is provided so as to guide the light incident on the other end 61b from the light emitting unit 64 to the one end 61a on the optical connector plug 63 side.

  One end 62a of the other control device side optical cable 62 is connected to the optical connector plug 63, and the other end 62b is connected to a light receiving unit 65 described later. The other control device side optical cable 62 is provided so as to guide the light incident on the one end 62a on the optical connector plug 63 side to the light receiving unit 65 connected to the other end 62b.

  When the filling nozzle 73 of the filling hose 71 is attached to the filling port 11 of the fuel tank 10, the optical connector plug 63 is fitted into the optical connector socket 23 provided in the filling port 11. When the optical connector plug 63 and the optical connector socket 23 are fitted, one end 61a of one control device side optical cable 61 and one end 21a of one fuel tank side optical cable 21 (that is, the inlet end of the optical path portion 48). 21a) is connected so as to be able to transmit light, and one end 62a of the other control device side optical cable 62 and one end 22a of the other fuel tank side optical cable 22 (that is, the outlet end 22a of the optical path section 48) transmit light. Connected as possible.

  The light emitting unit 64 includes, for example, a light emitting element such as an LED that outputs white visible light, a drive circuit that drives the light emitting element, and the like. In the present embodiment, the drive circuit periodically turns on and off the light emitting element so as to output pulsed light whose light amount changes at a constant period (hereinafter referred to as pulsed light (that is, periodic change light)). It consists of a repetitive pulse drive circuit. Of course, the drive circuit is not limited to this, and for example, is configured by a circuit that drives the light emitting element so as to continuously output a constant amount of light without a periodic change over a predetermined period. Also good.

  The light emitting unit 64 is connected to an output port PO1 of the MPU 67, which will be described later, and operates the drive circuit based on a control signal from the MPU 67 to output light from the light emitting element. The light emitting unit 64 is connected to the other end 61 b so that the output light is incident on the other end 61 b of the one control device side optical cable 61.

  As shown in FIG. 15A, the light receiving unit 65 includes a light receiving element 65a such as a phototransistor and a conversion circuit 65b that converts a signal output from the light receiving element 65a into a signal that can be input to the MPU 67. . In the present embodiment, the conversion circuit 65b includes a differentiation circuit 65b1 that outputs a signal indicating a change in received light, and a shaping circuit 65b2 that shapes the output waveform of the differentiation circuit 65b1, and the light receiving element 65a emits light. It is configured to output a state signal in which a single pulse having a small width is output when the light receiving state is changed to the light receiving state. FIG. 15B shows (i) the output waveform of the light receiving element 65a when receiving the pulsed light with the period T in the light receiving unit 65, (ii) the output waveform of the differentiating circuit 65b1, and (iii) shaping. An example of an output waveform (that is, a status signal) of the circuit 65b2 is shown. Of course, the conversion circuit is not limited to this, for example, a voltage level (for example, 0 V) indicating that the light receiving element receives light when the amount of received light is equal to or greater than a predetermined determination value. It may be configured by a circuit that outputs a state signal at a voltage level (for example, 5 V) indicating that the light receiving element is not receiving light when the value is less than the determination value.

  The light receiving unit 65 is connected to an input port PI of the MPU 67, which will be described later, and inputs a state signal indicating the state of received light to the MPU 67. The light receiving unit 65 is provided connected to the other end 62b so as to receive light emitted from the other end 62b of the other control device side optical cable 62.

  In the fuel supply control device 60, one control device side optical cable 61 and the light emitting unit 64 emit light to one end 21 a of one fuel tank side optical cable 21 of the liquid amount measurement device 20 (that is, the inlet end 21 a of the optical path portion 48). The other control device side optical cable 62 and the light receiving unit 65 are connected to one end 22a of the other fuel tank side optical cable 22 of the liquid amount measuring device 20 (that is, the optical path portion 48). A light receiving portion 69 for receiving the light emitted from the outlet end 22a) is formed.

  The supply speed control unit 66 includes a microcomputer (MPU) 67.

  The MPU 67 is composed of a known embedded microcomputer. The MPU 67 is a central processing unit (CPU) that performs various types of processing and control in accordance with a predetermined program, a ROM that is a read-only memory that stores processing programs and various information for the CPU, and various types of data. It has a RAM, which is a readable / writable memory that stores and has an area necessary for processing operations of the CPU.

  The light emitting unit 64 is connected to the output port PO1 of the MPU 67, and the CPU of the MPU 67 outputs a control signal for outputting or stopping the output of the pulse light from the light emitting unit 64 to the light emitting unit 64 through the output port PO1. To do. The fuel supply device 50 is connected to the output port PO2 of the MPU 67.

  The light receiving unit 65 is connected to the input port PI of the MPU 67, and the CPU of the MPU 67 receives the light receiving state (whether light is received) in the light receiving unit 65 based on the state signal from the light receiving unit 65 input to the input port PI. Is detected. Then, the CPU of the MPU 67 outputs a control signal for supplying the fuel F to the fuel supply device 50 through the output port PO2 at a supply speed corresponding to the light receiving state.

  Next, an example of processing (supply speed control processing) according to the present invention executed by the CPU of the MPU 67 described above will be described with reference to the flowchart shown in FIG.

  The CPU of the MPU 67 advances the process to step S110 shown in the flowchart of FIG. 16 at a predetermined timing (for example, every second).

  In step S110, the CPU outputs a control signal for outputting pulsed light having a constant period (eg, 1 ms (ie, frequency 1 kHz)) to the light emitting unit 64 through the output port PO1. When the light emitting unit 64 receives this control signal, the light emitting unit 64 outputs pulsed light having a constant period.

  In step S120, the light receiving state of the light receiving unit 65 is detected. Specifically, the CPU measures the pulse interval time included in the state signal input to the input port PI over a predetermined observation time (for example, 0.5 seconds), and calculates the period of the pulse. Then, the process proceeds to step S130.

  In step S130, the presence or absence of light reception in the light receiving unit 65 is determined. Specifically, when the interval time of the pulses included in the state signal calculated in step S120 is the same as that of the pulsed light emitted from the light emitting unit 64, the CPU determines that there is light reception and proceeds to step S140. (Y in S130), otherwise, it is determined that no light is received, and the process proceeds to step S150 (N in S130).

  In step S140, the supply rate of the fuel F is set to the maximum supply rate (for example, 10 [L / s]). Specifically, the CPU outputs a control signal for setting the supply rate of the fuel F to the maximum supply rate to the fuel supply device 50 through the output port PO2. The fuel supply device 50 supplies the fuel F at the supply speed indicated by the control signal, that is, the maximum supply speed. Then, the process proceeds to step S160.

  In step S150, the supply rate of the fuel F is gradually decreased to stop the supply of the fuel F, or when the supply rate is already 0 and the supply of the fuel F is stopped, the supply stop state is maintained. Specifically, the CPU gradually decreases the supply speed of the fuel F (for example, decelerates 1 [L / s] every second), and finally outputs a control signal for setting the speed to 0 at the output port PO2. To the fuel supply device 50. The fuel supply device 50 supplies the fuel F at a supply speed indicated by this control signal, that is, a speed at which the speed is gradually reduced from the maximum supply speed to zero. Alternatively, the fuel supply device 50 maintains this state when the fuel supply speed is already zero. Then, the process proceeds to step S160.

  In step S160, the CPU outputs a control signal for stopping the output of the pulsed light to the light emitting unit 64 through the output port PO1. The light emitting unit 64 stops the output of the pulsed light when receiving this control signal. And the process of this flowchart is complete | finished.

  Next, the operation (action) according to the present invention of the fuel filling system 1 described above will be described.

  When the filling nozzle 73 of the filling hose 71 is attached to the filling port 11 of the fuel tank 10 in order to supply the fuel F to the fuel tank 10 of the vehicle, the optical connector socket 23 and the optical connector plug 63 are fitted, The pair of fuel tank side optical cables 21 and 22 and the pair of control device side optical cables 61 and 62 are connected so as to be able to transmit light. Then, pulse light is output from the light emitting unit 64 at a predetermined timing (for example, every second) (S110).

  At this time, when the liquid level of the fuel F in the fuel tank 10 is less than the supply speed deceleration liquid level Ls, the light regulating magnet 45 of the liquid level switch 30 is positioned at the permissible position P1, and therefore the light output from the light emitting unit 64. The emitted light is emitted from one control device side optical cable 61, and one fuel tank side optical cable 21, one optical cable mounting portion 38, a first light guide member 41, a magnet moving space 46, a second light guide member 42, The light is guided to the light receiving unit 65 through the other control device side optical cable 62 through the other optical cable attachment portion 39 and the other fuel tank side optical cable 22 in order. That is, the pulsed light emitted from the light emitting unit 64 of the light emitting unit 68 is guided to the optical path unit 48 and received by the light receiving unit 65 of the light receiving unit 69.

  Thereby, the light receiving unit 65 outputs a received light, that is, a state signal including a pulse having the same cycle as the cycle of the pulsed light output from the light emitting unit 64, and the MPU 67 outputs the state signal pulse cycle and the light emitting unit. Assuming that the period of the 64 pulsed light is the same, it is determined that the light receiving unit 65 has received light, and the fuel F is supplied at the maximum supply speed (Y in S120 and S130, S140). Thereafter, the output of the pulsed light from the light emitting unit 64 is stopped (S160).

  Further, when the liquid level of the fuel F in the fuel tank 10 reaches the supply speed deceleration liquid level Ls, the light restriction magnet 45 of the liquid level switch 30 is positioned at the restriction position P2, so that the light output from the light emitting unit 64 is output. The emitted light is emitted from one control device side optical cable 61 and guided to one fuel tank side optical cable 21, one optical cable mounting portion 38, and the first light guide member 41, but the magnet moving space 46 The progress of the light is blocked by the light restricting magnet 45. That is, the pulsed light emitted from the light emitting unit 64 of the light emitting unit 68 is blocked in the middle of the optical path unit 48 and is not received by the light receiving unit 65 of the light receiving unit 69.

  Accordingly, the light receiving unit 65 outputs a state signal that does not include a pulse, and the MPU 67 assumes that the pulse period of this state signal (that is, an infinite period) and the period of the pulsed light of the light emitting unit 64 are not the same. Then, it is determined that there is no light reception by the light receiving unit 65, the supply speed is gradually decreased from the maximum supply speed to zero, and the supply of the fuel F is stopped (N in S120 and S130, S150). Thereafter, the output of the pulsed light from the light emitting unit 64 is stopped (S160).

  Further, when the filling nozzle 73 is detached from the filling port 11 due to an operation error or the like, the fitting between the optical connector socket 23 and the optical connector plug 63 is released. Thereby, the light which changes with the period different from the pulsed light output from the light emission units 64, such as light without a periodic change, such as an incandescent bulb light and sunlight, and the fluorescent lamp light, is sent to the other control device side optical cable 62. Incident light. That is, the pulsed light output from the light emitting unit 64 is not received by the light receiving unit 65, and the light that does not change periodically or the light that changes at a different period from the pulsed light is received.

  Accordingly, the light receiving unit 65 outputs a state signal that does not include a pulse or a state signal that includes a pulse having a period different from that of the pulsed light output from the light emitting unit, and the MPU 67 determines the pulse period of the state signal and the light emitting unit 64. Assuming that the period of the pulsed light is not the same, it is determined that no light is received by the light receiving unit 65, the supply speed is gradually reduced from the maximum supply speed to zero, and the supply of the fuel F is stopped (S120, N in S130, S150). Thereafter, the output of the pulsed light from the light emitting unit 64 is stopped (S160).

  As described above, the fuel filling system 1 of the present embodiment emits light to the liquid level switch 30 that emits the incident light in a state corresponding to the liquid level of the fuel F in the fuel tank 10 and the liquid level switch 30. And a fuel supply control device 60 for detecting the liquid level of the fuel F based on the state of the light emitted from the liquid level switch 30, and the liquid level switch 30 of the first embodiment described above. The liquid level switch 30 is used.

  As mentioned above, according to this embodiment, since the liquid level switch 30 is comprised by the liquid level switch 30 of Embodiment 1 mentioned above, according to the liquid level irrespective of electric power, the 1st light guide member 41 and The liquid level of the fuel F in the fuel tank 10 can be detected based on the change in the state of the light guided to the second light guide member 42 (the presence or absence of light). . In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

  In the present embodiment, the light emitting unit 64 emits pulsed light. However, the present invention is not limited to this, and the light emitting unit 64 emits a constant amount of light with no periodic state change. You may do. In this case, the conversion circuit of the light receiving unit 65, for example, has a voltage level (for example, 0V) indicating that light is received when the amount of received light is equal to or greater than a predetermined determination value, and no light is received when it is less than the determination value. The MPU 67 determines the light receiving state (light receiving presence / absence) based on the voltage level of the signal input to the input port PI.

  Further, in the present embodiment, the liquid level switch 30 of the first embodiment described above is provided. However, instead, the liquid level switch 30A of the second embodiment described above may be provided.

  In this configuration, the light receiving unit 65 (1) receives red light and blue light (that is, less than the first supply speed deceleration liquid level Ls1), and (2) receives blue light (that is, the first light Different status signals when the supply speed deceleration liquid level is Ls1 or more and less than the second supply speed deceleration liquid level Ls2, and (3) when no light is received (that is, the second supply speed deceleration liquid level Ls2 or more). Then, in the MPU 67, for example, (1) when receiving a status signal indicating that red light and blue light are received, the fuel F is supplied at the maximum supply speed, and (2) When the status signal indicating that the blue light is received is received, the fuel F is supplied at a predetermined intermediate supply speed slower than the maximum supply speed, and (3) the status signal indicating that the light is not received is received. When the supply speed is intermediate As zero velocity is gradually reduced from the sheet speed to stop the supply of the fuel F, for controlling the fuel supply device 50 as.

  Further, in the present embodiment, the liquid level switch 30 of the first embodiment described above is provided. However, instead, the liquid level switch 30B of the third embodiment described above may be provided.

  In the case of this configuration, the light receiving unit 65 is configured to output a status signal indicating the proportion of the wavelength range in which light is received in a predetermined wavelength range. Specifically, for example, when a predetermined wavelength range is 400 nm to 500 nm, a state signal indicating 100% is output when light in the wavelength range of 400 nm to 500 nm is received, and light in the wavelength range of 400 nm to 480 nm is output. When it receives light, it outputs a status signal indicating 80%, when it receives light in the wavelength range of 400 nm to 430 nm, it outputs a status signal indicating 30%, and when it does not receive light, it outputs a status signal indicating 0%. To be configured. In the MPU 67, when the ratio indicated by the received status signal is less than 30% (that is, less than the supply speed deceleration liquid level Ls), the fuel F is supplied at the maximum supply speed. The fuel supply device 50 is controlled so that the supply speed is gradually reduced every time it increases by 1%, and the supply speed becomes zero when the ratio indicated by the received status signal is 0%.

  As described above, by using the liquid level switch 30A of the second embodiment or the liquid level switch 30B of the third embodiment instead of the liquid level switch 30 of the first embodiment, more detailed liquid level detection can be performed. In addition, since the liquid level is detected based on the wavelength of light, it is less susceptible to light attenuation and the like, and the liquid level detection accuracy can be improved compared to a configuration that changes the light state (luminance). it can.

(Embodiment 6)
Hereinafter, a fuel filling system which is another embodiment of the liquid level detection system of the present invention will be described with reference to FIG.

  As shown in FIG. 17, the fuel filling system 2 includes a liquid amount measuring device 20A disposed in a fuel tank 10 mounted on a vehicle, a fuel supply device 50, and a fuel supply control device 60 as a liquid level detecting means. And have.

  The present embodiment is the same as the fifth embodiment except that in the configuration of the fifth embodiment described above, the liquid amount measuring device 20 is replaced by the liquid amount measuring device 20A. Are denoted by the same reference numerals and description thereof is omitted.

  The liquid amount measuring device 20A includes an optical connector socket 23 provided in the filling port 11 of the fuel tank 10, a pair of fuel tank side optical cables 24 and 25, a common optical cable 26, a light separating member 27, and the inside of the fuel tank 10. And the above-described liquid level switch 30C for measuring the liquid level height.

  The pair of fuel tank side optical cables 24 and 25 and the common optical cable 26 are provided with an optical fiber and a protective coating (sheath) covering the periphery thereof, and guide light emitted to one end to emit light to the other end. It is an optical cable. The pair of fuel tank side optical cables 24 and 25 and the common optical cable 26 are routed on the outer surface of the fuel tank 10.

  One end 24a of one fuel tank side optical cable 24 is connected to an optical connector socket 23 provided in the filling port 11 of the fuel tank 10, and the other end 24b is connected to an input terminal 27a of a light separating member 27 described later. Has been. The one fuel tank side optical cable 24 is provided so as to guide the light incident on the one end 24a on the optical connector socket 23 side to the light separating member 27 connected to the other end 24b.

  One end 25a of the other fuel tank side optical cable 25 is connected to the optical connector socket 23, and the other end 25b is connected to an output terminal 27b of a light separating member 27 described later. The other fuel tank side optical cable 25 is provided so as to guide the light incident on the other end 25b from the light separating member 27 to the one end 25a on the optical connector socket 23 side.

  One end 26a of the common optical cable 26 is connected to an input / output terminal 27c of a light separation member 27, which will be described later, and the other end 26b is connected to an optical cable attachment portion 138 of the liquid level switch 30C. The common optical cable 26 guides the light incident on the one end 26a on the light separating member 27 side to the optical cable attaching portion 138 connected to the other end 26b, and is input to the other end 26b on the optical cable attaching portion 138 side. It is provided so as to guide the light to the light separating member 27 connected to the one end 26a.

  The light separating member 27 includes, for example, a polarizing beam splitter, a quarter-wave plate, and the like, and outputs light incident on the input terminal 27a from the input / output terminal 27c and enters the input / output terminal 27c. The light emitted is emitted from the output terminal 27b.

  The liquid level switch 30C has the configuration of the fourth embodiment described above.

  In the liquid amount measuring device 20A, one fuel tank side optical cable 24, a light separating member 27 (from the input terminal 27a to the input / output terminal 27c), a common optical cable 26 (from one end 26a to the other end 26b), an optical cable mounting portion 138, a guide Optical member 141 (from one end 141a to the other end 141b), magnet moving space 146, light reflecting member 160, light guide member 141 (from the other end 141b to one end 141a), optical cable mounting portion 138, common optical cable 26 (from the other end 26b) One end 26a), the light separating member 27 (from the input / output terminal 27c to the output terminal 27b), and the other fuel tank side optical cable 25 constitute one optical path portion 48A. The optical path portion 48A uses the light incident on one end 24a (hereinafter also referred to as “inlet end 24a”) of one fuel tank side optical cable 24 as an inlet end to the other fuel tank side optical cable as an outlet end. 25 is led to one end 25a (hereinafter also referred to as "exit end 25a").

  About the operation | movement (action) which concerns on this invention of the fuel filling system 2 of this embodiment, it is the same as that of the fuel filling system 1 of Embodiment 5 mentioned above.

  As described above, the fuel filling system 2 of the present embodiment emits light to the liquid level switch 30C that emits the incident light in a state corresponding to the liquid level of the fuel F in the fuel tank 10, and to the liquid level switch 30C. And a fuel supply control device 60 that detects the liquid level of the fuel F based on the state of the light emitted from the liquid level switch 30C, and the liquid level switch 30C is the same as that of the above-described fourth embodiment. The liquid level switch 30C is used.

  As described above, according to the present embodiment, since the liquid level switch 30C is configured by the liquid level switch 30C of the above-described fourth embodiment, the liquid level switch 30C reciprocates according to the liquid level regardless of the power. The liquid level of the fuel F in the fuel tank 10 can be detected based on the change of the light state. In addition, since it operates without depending on electric power, no explosion-proof measures are required, and a simple configuration can be achieved.

  In the first embodiment described above, the light restricting magnet 45 as the moving wall portion and the magnet float 47 as the float portion are both configured by the magnetic force generating means for generating a magnetic force. It is not a thing. For example, in the configuration of the first embodiment, a light regulating member 45 ′ made of a magnetic material such as iron is provided in place of the light regulating magnet 45, and a spring 97 is newly provided to suspend and hold the light regulating member 45 ′. The liquid level switch 30D shown in FIG. 18 may be used.

  In this liquid level switch 30D, the same operation (action) as in the first embodiment can be obtained.

  That is, when the level of the fuel F in the fuel tank 10 is low and there is no fuel F in the lower space 34 of the case 31, the magnet float 47 is positioned on the bottom wall portion 32b. At this time, since the light restricting magnet 45 is in the allowable position P1 ′ near the upper support member 43, the light emitted from the second end face 41b of the first light guide member 41 passes through the magnet moving space 46 to the second light guide member. Light can enter the first end surface 42a of 42.

  When the liquid level of the fuel F in the fuel tank 10 rises and the fuel F flows into the lower space 34 from the communication hole 35, the magnet float 47 floats on the fuel F and reaches the liquid level of the fuel F in the fuel tank 10. Moved accordingly.

  When the liquid level of the fuel F in the fuel tank 10 reaches a predetermined supply speed deceleration liquid level Ls, the magnet float 47 is moved to a position where the upper surface thereof abuts against the partition wall portion 32d. At this time, the light restricting member 45 ′ is attracted downward by the magnetic force between the magnet float 47 and moved to the restricting position P2 ′ closer to the partition wall 32d. Therefore, the second end face of the first light guide member 41 The light emitted from 41b is blocked by the light restricting magnet 45 and cannot enter the first end surface 42a of the second light guide member 42.

  In this way, the magnet float 47 is configured by magnetic force generation means, and the light regulating member 45 ′ is disposed in the upper space 33 separated from the fuel tank 10, and 45 ′ is configured by a magnetic material, and the light regulating member The member 45 ′ may be configured to be moved by a magnetic force generated between the member 45 ′ and the magnet float 45. On the other hand, in the configuration of the first embodiment, the light restricting magnet 45 is configured by a magnetic force generating means, and a float portion made of a material containing a magnetic body is provided instead of the magnet float 47. Also good. The same applies to Embodiments 2 to 4.

  In the first embodiment described above, the light regulating magnet 45 and the magnet float 47 themselves are magnetic force generating means. However, the present invention is not limited to this, and a combination of a member having no magnetic force and a magnet having magnetic force is used. These may be configured. The same applies to Embodiments 2 to 4.

  Although Embodiment 5 and 6 mentioned above demonstrated the fuel filling system for vehicles which fills the fuel tank mounted in the vehicle with fuel, it is not limited to this. For example, a liquid level meter that is provided in a fuel filling system that fills a fuel tank installed in a factory or home, or a liquid tank that contains liquid, and detects and displays the liquid level in the liquid tank. An apparatus or the like may be used, and a system (including an apparatus) to which the present invention is applied is arbitrary as long as the object of the present invention is not violated. In addition, the fuel to be filled is not limited to liquefied petroleum gas (LPG), for example, liquefied gas such as dimethyl ether (DME), liquid hydrogen, and liquefied methane, fuel that becomes liquid at room temperature and normal pressure (kerosene, gasoline, etc.), As long as the object of the present invention is not violated, the type is arbitrary.

  In addition, embodiment mentioned above only showed the typical form of this invention, and this invention is not limited to embodiment. That is, various modifications can be made without departing from the scope of the present invention.

1, 2 Fuel filling system (Liquid level detection system)
10 Fuel tank (liquid tank)
20, 20A Liquid volume measuring device 30, 30A, 30B Liquid level switch 31 Case 41 First light guide member 41a First end surface 41b Second end surface (light exit surface)
41c Reflective surface 42 Second light guide member 42a First end surface (light incident surface)
42b Second end face 42c Reflective surface 45 Light restricting magnet (moving wall, magnetic force generating means)
46 Magnet movement space 47 Magnet float (float part, magnetic force generation means)
50 Fuel supply device 60 Fuel supply control device (liquid level detection means)
80 Optical filter member (wavelength filter)
81 Blue transmission filter part (filter part)
82 Red transmission filter part (filter part)
85 Optical filter member (wavelength filter)
90 Magnet float (float part, magnetic force generation means)
30C Liquid level switch 131 Case 141 Light guide member 141a First end surface 141b Second end surface (one end surface)
141c Reflective surface 145 Light restricting magnet (moving wall, magnetic force generating means)
146 Magnet moving space 147 Magnet float (float part, magnetic force generating means)
150 Light Absorbing Member 160 Light Reflecting Member F Fuel (Liquid)
L0 Empty liquid level P1 Permissible position P2 Restricted position P3 Intermediate position Q1 Permissible position Q2 Restricted position Ls Supply speed deceleration liquid level Lm Maximum filling liquid level, full liquid level Ls1 First supply speed deceleration liquid level Ls2 Second supply speed deceleration Liquid level

Claims (6)

In the liquid level switch used to detect the liquid level in the liquid tank,
A first light guide member;
A second light guide provided with a light incident surface arranged opposite to the light output surface of the first light guide member so as to continuously guide the light guided by the first light guide member. An optical member;
A float that floats on the liquid in the liquid tank;
A moving wall portion moved so as to be inserted between the light exit surface and the light entrance surface by the movement of the float portion;
A liquid level switch characterized by comprising: One of the float part and the moving wall part has a magnetic force generating means, the other has a magnetic body,
2. The moving wall portion is disposed in a space isolated from the liquid tank and is configured to be moved by a magnetic force generated between the floating wall portion and the float portion. Liquid level switch as described.   The float moves the moving wall at a predetermined rate with respect to a change in the liquid level of the liquid level tank so that the moving wall is inserted between the light exit surface and the light entrance surface. The liquid level switch according to claim 1, wherein the liquid level switch is configured to be made to be configured.   At least one of the light exit surface of the first light guide member and the light entrance surface of the second light guide member has a plurality of filter portions that allow light of different wavelengths to pass in the moving direction of the moving wall portion. The liquid level switch according to any one of claims 1 to 3, wherein a wavelength filter arranged side by side is provided. In the liquid level switch used to detect the liquid level in the liquid tank,
One light guide member capable of guiding light in both directions;
A light-absorbing member disposed opposite to the one end surface of the light guide member,
A float that floats on the liquid in the liquid tank;
A moving wall portion that is moved so as to be inserted between one end surface of the light guide member and the light absorbing member by movement of the float portion;
A light reflecting member provided on the moving wall portion so as to face the one end surface of the light guide member when the moving wall portion is between the one end surface of the light guide member and the light absorbing member;
A liquid level switch characterized by comprising: In the liquid level detection system that detects the liquid level in the liquid tank,
A liquid level switch for emitting the incident light in a state corresponding to the liquid level in the liquid tank;
Liquid level detection means for detecting the liquid level based on the state of light emitted from the liquid level switch and entering light into the liquid level switch;
The liquid level switch is configured by the liquid level switch according to any one of claims 1 to 5.

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