Water replenishment device

Abstract

The objective is to provide a water supply device that makes it difficult for liquid to leak from the water supply port. [Solution] The water replenishment device 100 is equipped with a float 120 and a first magnet 124, and a water shut-off valve 136 attached to the first magnet 124 in the water replenishment pipe 130. A water replenishment port 135 for replenishing water in the liquid tank 7a is opened in a direction that the water shut-off valve 136 is attracted to by the first magnet 124. As the liquid level S in the liquid tank 7a rises, the float 120 rises, bringing the first magnet 124 closer to the water shut-off valve 136, and the attractive force of the first magnet 124 acts on the water shut-off valve 136. This attractive force causes the water shut-off valve 136 to be attracted toward the water replenishment port 135, so that the water replenishment port 135 can be stably closed. As a result, it is difficult for liquid to leak from the water replenishment port 135.

Description

Technical Field

[0001] The present invention relates to a water replenishing device, and more particularly to a water replenishing device that can hardly cause liquid leakage from a water replenishing port.

Background Art

[0002] In a water replenishing device including a main body (device main body) disposed in a case, a float configured to move up and down in accordance with the water level of the liquid filled in the case and disposed on the device main body, and a water replenishing plate disposed on the device main body and having a water replenishing port that opens into the case, there is known a water replenishing device in which the float and a water stop valve are mechanically connected via a connecting member (Patent Document 1). According to this water replenishing device, when the water level of the liquid drops, the downward movement of the float is transmitted to the water stop valve via the connecting member, and the water stop valve moves away from the water replenishing port. As a result, the water replenishing port is opened and water replenishment is started. When the water level of the liquid rises, the upward movement of the float is transmitted to the water stop valve via the connecting member, and the water stop valve is brought into contact with the water replenishing port. As a result, the water replenishing port is closed and water replenishment is stopped.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above-described conventional technology, there are parts that are mechanically connected in the structure for closing the water replenishing port, and the water stop valve is mechanically brought into contact with the water replenishing port. Therefore, due to variations in dimensional accuracy of each part and the influence of snagging between parts, it is impossible to reliably close (stop water) the water replenishing port with the water stop valve, and there is a problem that liquid leakage from the water replenishing port easily occurs.

[0005] The present invention was made to solve the above-mentioned problems, and aims to provide a water supply device that can make it difficult for liquid to leak from the water supply port. [Means for solving the problem]

[0006] To achieve this objective, the water replenishment device of the present invention comprises a device body disposed in a case filled with liquid, a float disposed in the device body and configured to move up and down in accordance with the water level of the liquid filled in the case, and a tubular water replenishment pipe disposed in the device body and having a water replenishment port opening into the case, wherein the water replenishment pipe is equipped with a shut-off valve configured to open and close the water replenishment port, the float is equipped with a first magnet configured to attract the shut-off valve by magnetic force, the water replenishment port is located between the first magnet and the shut-off valve in a top view of the device body, the first magnet is positioned to approach the shut-off valve as the float rises and to move away from the shut-off valve as the float descends, and closes the water replenishment port by approaching the shut-off valve and acting an attractive force on the shut-off valve in the direction toward the water replenishment port.

[0007] The water replenishment device of the present invention comprises a device body disposed in a case filled with liquid, a float disposed in the device body and configured to move up and down in accordance with the water level of the liquid filled in the case, and a tubular water replenishment pipe disposed in the device body and having a water replenishment port opening into the case, for replenishing water to the liquid filled in the case, wherein the water replenishment pipe is equipped with a shut-off valve configured to open and close the water replenishment port and at least a part of which is made of a magnet, the float is equipped with a third magnet configured to repel the shut-off valve by magnetic force, the water replenishment port is located on the opposite side of the shut-off valve from the third magnet in a top view of the device body, the third magnet is positioned to approach the shut-off valve as the float rises and to move away as the float descends, and closes the water replenishment port by approaching the shut-off valve and acting a repulsive force on the shut-off valve in the direction toward the water replenishment port. [Effects of the Invention]

[0008] According to the water supply device described in claim 1, the water supply pipe is equipped with a shut-off valve configured to open and close the water supply port, the float is equipped with a first magnet configured to attract the shut-off valve by magnetic force, the water supply port is located between the first magnet and the shut-off valve in a top view of the device body, the first magnet is positioned to approach the shut-off valve as the float rises and to move away as the float descends, and by approaching the shut-off valve and acting an attractive force toward the shut-off valve toward the water supply port, the water supply port is closed, so that the water supply port can be closed even when the float and the shut-off valve are not mechanically connected. Therefore, since there is no need for a part to mechanically connect the float and the shut-off valve, it is possible to reduce the influence of variations in the dimensional accuracy of each part involved in the closing operation of the water supply port and snagging between parts. As a result, it is possible to reduce the likelihood of liquid leakage from the water supply port.

[0009] Furthermore, the first magnet is positioned so that it approaches the shut-off valve as the float rises and moves away as the float descends. By approaching the shut-off valve and applying an attractive force toward the shut-off valve toward the water inlet, the water inlet is closed. Therefore, when the water inlet is closed by the shut-off valve, the distance between the shut-off valve and the first magnet is shorter than when the shut-off valve began to be attracted toward the water inlet by the first magnet. This makes it possible to increase the attractive force acting on the shut-off valve when it is closing the water inlet compared to when the shut-off valve began to be attracted toward the water inlet. As a result, the force with which the shut-off valve presses against the water inlet can be increased. This makes it easier to reliably close the water inlet and makes it less likely for liquid to leak from the water inlet.

[0010] According to the water supply device of claim 2, in addition to the effects of the water supply device of claim 1, the shut-off valve is movably disposed within the internal space of the water supply pipe, and a gap is formed between the bottom surface of the water supply pipe and the lowest end of the shut-off valve when the shut-off valve is in a water-stopping state that closes the water supply port. Therefore, when the shut-off valve moves away from the water supply port and the water supply port is opened, the shut-off valve can be moved (dropped) to the bottom surface of the water supply pipe by its own weight. Thus, the shut-off valve can be easily separated from the water supply port. As a result, the water supply port can be easily opened.

[0011] According to the water supply device of claim 3, in addition to the effects of the water supply device of claim 1 or 2, the bottom surface of the water supply pipe is sloped downward as it moves away horizontally from the water supply port, and the shut-off valve has a circular or ring-shaped cross-section when cut by a plane perpendicular to the axis of rotation on which the bottom surface of the water supply pipe rolls, and is configured to be able to roll on the bottom surface of the water supply pipe. Therefore, when the shut-off valve moves away from the water supply port and the water supply port is opened, the shut-off valve can be rolled toward the opposite side of the water supply port relative to the bottom surface of the water supply pipe. Thus, the shut-off valve can be moved to a position far from the water supply port and below the water supply port. As a result, it is difficult for the shut-off valve to return to the water supply port side due to the water flow of the liquid supplied to the water supply pipe. As a result, it is easier to maintain the open state (water supply state) of the water supply port.

[0012] According to the water supply device of claim 4, in addition to the effects of the water supply device of claim 1, the float is provided with a second magnet positioned above the first magnet and having opposite poles to the first magnet, the water supply port is located between the second magnet and the shut-off valve in a top view of the device body, the shut-off valve is at least partially composed of a magnet, the second magnet is positioned so as the float rises it moves away from the shut-off valve and as the float descends it moves closer to the shut-off valve, and the water supply port is opened by the second magnet acting as a repulsive force that moves away from the water supply port as it approaches the shut-off valve, so it is easier to reliably open the water supply port compared to cases where the water supply port is opened using the weight of the shut-off valve or by a mechanical method (such as a spring that biases in the opening direction). Therefore, it is possible to make it difficult for insufficient water supply to occur inside the case.

[0013] According to the water supply device described in claim 5, the water supply pipe is equipped with a shut-off valve configured to open and close the water supply port and at least a part of which is made of a magnet, the float is equipped with a third magnet configured to repel the shut-off valve by magnetic force, the water supply port is located on the opposite side of the shut-off valve from the third magnet when viewed from above the main body of the device, the third magnet is positioned so as the float rises and as the float descends the shut-off valve, and closes the water supply port by acting a repulsive force that is generated in the direction toward the water supply port as the magnet approaches the shut-off valve, so that the water supply port can be closed even when the float and the shut-off valve are not mechanically connected.Therefore, a part to mechanically connect the float and the shut-off valve is not required, and the effects of variations in the dimensional accuracy of each part involved in the closing operation of the water supply port and snagging between parts can be reduced.As a result, it is possible to reduce the likelihood of liquid leakage from the water supply port.

[0014] According to the water supply device of claim 6, in addition to the effects of the water supply device of claim 5, the float is provided with a fourth magnet positioned above the third magnet and having opposite poles to the third magnet, the water supply port is located on the opposite side of the shut-off valve from the fourth magnet when viewed from above the device body, the fourth magnet is positioned so as the float rises and as the float descends the shut-off valve, and the water supply port is opened by the fourth magnet moving away from the shut-off valve as it approaches the shut-off valve and acting an attractive force that moves away from the water supply port relative to the shut-off valve as it approaches the shut-off valve. Therefore, it is easier to reliably open the water supply port compared to cases where the water supply port is opened using the weight of the shut-off valve or by a mechanical method (such as a spring that biases in the opening direction). Thus, it is less likely to cause a shortage of water supply inside the case.

[0015] According to the water replenishment device of claim 7, in addition to the effects of the water replenishment device of claim 1 or 5, the float is configured to rise to a second position above the first position in which the shut-off valve can close the water replenishment port due to the magnetic force acting on the shut-off valve from the first magnet or the third magnet. Therefore, even if, for example, foreign matter is caught between the shut-off valve and the water replenishment port, resulting in insufficient closure of the water replenishment port by the shut-off valve, and water is added in excess of the water level when the float is in the first position, this condition (the state of excessive water replenishment) can be confirmed. Thus, it is possible to distinguish between cases where the water replenishment port is properly closed by the shut-off valve and cases where it is not.

[0016] According to the water replenishment device of claim 8, in addition to the effects of the water replenishment device of claim 1 or 5, the device body is equipped with a rotation restricting means that restricts the rotation of the float around the axis extending in the vertical direction, so that the rotation of the float around the axis can be restricted and the direction in which the float faces the water replenishment pipe can be maintained in a constant direction. Therefore, the distance between the first magnet or the third magnet and the shut-off valve at a water level of 1 can be kept substantially constant. As a result, the magnetic force of the first magnet or the third magnet can be stably applied to the shut-off valve. As a result, it is possible to make it difficult for insufficient water replenishment or leakage of liquid from the water replenishment port to occur. [Brief explanation of the drawing]

[0017] [Figure 1] This is a perspective view of a battery equipped with a water replenishment device according to the first embodiment. [Figure 2] This is a longitudinal cross-sectional view of the water replenishment device. [Figure 3] (a) is a partially enlarged cross-sectional view of the water supply device along the line IIIa-IIIa in Figure 2, (b) is a partially enlarged cross-sectional view of the water supply device at part IIIb in Figure 2, and Figure 3(c) is a partially enlarged cross-sectional view of the water supply device 100 in a state where the shut-off valve is attracted to the rear side by the first magnet. [Figure 4] (a) is a cross-sectional view of the water supply device when the float is at its lower limit in an underwater level condition, (b) is a cross-sectional view of the water supply device when the water level is at the upper limit of the appropriate water level condition, and (c) is a cross-sectional view of the water supply device when the float is at its upper limit (the float is in the second position) in an overwater level condition. [Figure 5] (a) is a cross-sectional view of the water replenishment device of the second embodiment in a state of insufficient water level where the float is at its lower limit, and (b) is a cross-sectional view of the water replenishment device in a state of appropriate water level where the water level is at the upper limit of the appropriate water level. [Figure 6] (a) is a cross-sectional view of the water replenishment device of the third embodiment in a state of insufficient water level where the float is at its lower limit, and (b) is a cross-sectional view of the water replenishment device in a state of appropriate water level where the water level is at the upper limit of the appropriate water level. [Figure 7] (a) is a cross-sectional view of the water replenishment device of the fourth embodiment in a state of insufficient water level where the float is at its lower limit, and (b) is a cross-sectional view of the water replenishment device in a state of appropriate water level where the water level is at the upper limit of the appropriate water level. [Figure 8] (a) is a cross-sectional view of the water replenishment device of the fifth embodiment in a state of insufficient water level where the float is at the lower limit; (b) is a cross-sectional view of the water replenishment device in a state of appropriate water level where the water level is at the upper limit of the appropriate water level; (c) is a cross-sectional view of the water replenishment device along the line VIIIc-VIIIc in (a); and (d) is a partial cross-sectional view of the water replenishment device along the line VIIId-VIIId in (b). [Figure 9] (a) is a partial cross-sectional view of the water replenishing device in the first modification, (b) is a partial cross-sectional view of the water replenishing device taken along line IXb-IXb of (a), and (c) is a partial cross-sectional view of the water replenishing device in the second modification.

Mode for Carrying Out the Invention

[0018] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a battery 1 including a water replenishing device 100 in the first embodiment. In FIG. 1, a part of the battery case 2 and the cell 7 is shown in cross section, and the water supply tank 3, the pipe 4, the valve 6, and the pipe 8 are schematically shown.

[0019] As shown in FIG. 1, the battery 1 is used as power for an industrial vehicle such as an automated guided vehicle, and includes a battery case 2 and a plurality (24 in this embodiment) of cells 7 disposed in the battery case 2. Each of the plurality of cells 7 is filled with a battery liquid composed of dilute sulfuric acid.

[0020] Water is supplied to each cell 7 via a pipe 4 connected from a water supply tank 3 installed outside the battery 1. A connection pipe 5 is connected to each of the cells 7. The connection pipe 5 forms a path for supplying the water supplied via the pipe 4 to other cells 7. A valve 6 for switching the stop or start of the supply of water from the water supply tank 3 is disposed in the pipe 4.

[0021] A water replenishing device 100 for supplying water to the liquid tank 7a of the cell 7 is disposed in the cell 7. The water replenishing device 100 is disposed at a liquid port 7b (see FIG. 2) that penetrates the liquid tank 7a of the cell 7.

[0022] A pipe 8 is connected to the most downstream cell 7 to which water is supplied from the water supply tank 3. Excess water that has passed through the water replenishing devices 100 disposed in all the cells 7 is recovered to the water supply tank 3 via the pipe 8.

[0023] Next, with reference to Figure 2, the water replenishment device 100 in the first embodiment will be described. Figure 2 is a longitudinal cross-sectional view of the water replenishment device 100. In Figure 2, the arrows U, D, F, B, L, and R directions are described as the upward, downward, forward, backward, left, and right directions of the water replenishment device 100, respectively (the same applies to Figures 3 to 9). In Figure 2, the hatching of the shut-off valve 136 is omitted to simplify the drawing (the same applies to the shut-off valves 136 and 636 in Figures 3(b), 3(c), 4, 8(a), 8(b), 9(b), and 9(c)).

[0024] As shown in Figure 2, the water replenishment device 100 is a device that, when the battery fluid in the liquid tank 7a of cell 7 decreases to the insufficient level described later (liquid level S (water level) drops), supplies water from the water supply tank 3 via the piping 4 and connecting pipe 5 to the liquid tank 7a of cell 7 (supplies water), and stops supplying water (shuts off) when the battery fluid in the liquid tank 7a of cell 7 increases to the appropriate level described later (liquid level S (water level) rises).

[0025] The water replenishment device 100 comprises a device body 110 fixed to the liquid tank 7a, a float 120 disposed within the device body 110 and configured to move up and down in accordance with the rise and fall of the liquid level S (water level) of the battery fluid in the liquid tank 7a, and a water replenishment pipe 130 disposed within the device body 110 and having a water replenishment port 135 formed therein.

[0026] The water supply device 100 can maintain a stable water-stopped state by blocking the water supply port 135 by applying the attractive force of the first magnet 124, which is disposed on the float 120, to the shut-off valve 136 disposed inside the water supply pipe 130.

[0027] The device body 110 comprises a cylindrical main body portion 111 whose outer surface is fitted into the liquid port 7b (see Figure 2) of the cell 7, and a cap 112 that covers the upper part of the main body portion 111 in an openable and closable manner. The main body portion 111 and the cap 112 are made of synthetic resin material, and the cap 112 is made of a light-transmitting material. The water replenishment device 100 also functions as a stopper to close the liquid port 7b due to the above configuration.

[0028] The main body portion 111 is provided with a hole 113a that penetrates in the vertical direction, and a guide portion 113 that protrudes from the radial inner circumferential surface side of the main body portion 111 toward the center.

[0029] The guide portion 113 has a rectangular cross-section. The guide portion 113 comprises an upper surface 113c that is flush with the upper surface of the main body portion 111, a counterbore hole 113b that is recessed downward from the upper surface 113c and communicates with the upper end of the hole 113a, and has an inner surface that is larger than the inner surface of the hole 113a, and a seating surface 113b1 that forms the bottom of the counterbore hole 113b. The height of the upper surface 113c is set to a height that creates a space between it and the lower surface of the cap 112 when the cap 112 is closed. The counterbore hole 113b has a circular cross-section.

[0030] Here, the hole 113a of the guide portion 113 will be described with reference to Figure 3(a). Figure 3(a) is a partially enlarged cross-sectional view of the water supply device 100 along the line IIIa-IIIa in Figure 2. In Figure 3(a), the rear side of the guide portion 113 is partially omitted from the illustration. The hole 113a of the guide portion 113 is a part that restricts the rotation of the float 120, which is inserted into the guide portion 113 so as to be vertically movable, around an axis parallel to the vertical direction. The cross-section of the hole 113a is rectangular.

[0031] The level gauge 121, described later, has a rectangular cross-section with an outer diameter smaller than the inner diameter of the hole 113a. The level gauge 121 is inserted into the hole 113a so as to be slidable in the vertical direction.

[0032] Let's return to Figure 2 for explanation. The float 120 is configured as a float and is a component that moves up and down in accordance with the water level of the battery fluid filled in the liquid tank 7a. The float 120 comprises a floating portion 122 that floats on the liquid surface S, a level gauge 121 extending above the floating portion 122, and an indicator portion 123 protruding from the outer surface of the level gauge 121. The floating portion 122, the level gauge 121, and the indicator portion 123 are made of synthetic resin. The floating portion 122 is cylindrical, and its outer diameter is set to be larger than the inner diameter of the hole 113a.

[0033] The level gauge 121 is set to a length such that a gap is formed between the upper surface of the float portion 122 and the lower surface of the main body portion 111 (guide portion 113) when its upper end surface is in contact with the lower surface of the cap 112 (when the float 120 is in the second position) (see Figure 4(c)).

[0034] A first magnet 124 is positioned on the front (front) side of the lower end (the side connected to the floating portion 122) of the level gauge 121. In this embodiment, a level gauge 121 is molded with a recess provided in advance so that the first magnet 124 can be positioned, and the first magnet 124 is bonded to the recessed portion.

[0035] The first magnet 124 is a flat, plate-shaped permanent magnet (a neodymium magnet in this embodiment) that extends in the vertical direction. In this embodiment, the first magnet 124 has an N pole and a S pole on its front and back sides in the thickness direction (front-to-back direction). At least the front surface of the first magnet 124 is coated with a fluororesin coating to improve corrosion resistance, sliding properties, and wear resistance.

[0036] The indicator portion 123 is for indicating the water level of the battery fluid filled in the fluid tank 7a, and is a circular disc shape when viewed from above. The outer diameter of the indicator portion 123 is set to be smaller than the inner diameter of the counterbore hole 113b, and larger than the inner shape of the hole 113a. When the level gauge 121 is inserted through the hole 113a of the guide portion 113, the indicator portion 123 is positioned above the seat surface 113b1 and is slidable inside the counterbore hole 113b. Therefore, when the level gauge 121 is inserted through the hole 113a of the guide portion 113, even if the water level of the battery fluid drops, the lower surface of the indicator portion 123 abuts against the seat surface 113b1, restricting the float 120 from moving below that position (lower limit of the float 120) (see Figure 4(a)).

[0037] The distance from the position where the indicator portion 123 protrudes from the outer surface of the level gauge 121 to the lower end of the level gauge 121 is set to be greater than the vertical length of the guide portion 113. Therefore, the float 120 can rise above the point where the upper surface of the indicator portion 123 is approximately flush with the upper surface 113c.

[0038] The indicator section 123 is set so that the upper surface of the indicator section 123 is approximately flush with the upper surface 113c, and the battery fluid level is at the upper limit of the appropriate level (a certain range of fluid level within which the electrodes arranged in the fluid tank 7a are not exposed to the battery fluid). If the indicator section 123 is above the upper surface 113c, it can be confirmed that the battery fluid level is at an excess level (a level where the battery fluid is filled in excess of the upper limit of the appropriate level).

[0039] Since the cap 112 is made of a light-transmitting material, it is easy to check whether the indicator portion 123 is above or below the upper surface 113c, even when the cap 112 is closed, when checking the height of the indicator portion 123.

[0040] The water supply pipe 130 is a tubular member for replenishing the liquid tank 7a with water supplied from the water supply tank 3. The water supply pipe 130 has an upper part 131 that extends in the left-right direction and is connected to connecting pipes 5 arranged on the left and right sides of the water supply device 100, and a lower part 132 that hangs down from the center of the upper part 131 in the left-right direction. The upper part 131 is a cylindrical portion that communicates with the connecting pipe 5 and supplies water supplied from the water supply tank 3 via the piping 4 and the connecting pipe 5 to the lower part 132.

[0041] Now, with reference to Figure 3(b), the lower part 132 of the water supply pipe 130 will be described. Figure 3(b) is a partially enlarged cross-sectional view of the water supply device 100 in part IIIb of Figure 2. Note that Figure 3(b) shows the state in which the shut-off valve 136 is blocking the water supply port 135.

[0042] The lower section 132 has a rectangular cross-section and comprises four side walls 133 extending in the vertical direction, and a bottom wall 134 connected to the lower ends of the four side walls 133 to form a bottom surface 134a. Furthermore, a spherical water stop valve 136 is movably disposed inside the lower section 132.

[0043] A water inlet 135 is formed at the lower end of the rear side wall 133, opening to the inside of the main body 111 and to the liquid tank 7a. A regulating portion 137 is formed on the side wall 133 above the water inlet 135, protruding inward from the inner surface of the side wall 133. An annular O-ring 138 is disposed on the inner surface of the side wall 133 along the water inlet 135. The bottom wall 134 is shaped such that the bottom surface 134a slopes downward as it moves away from the water inlet 135 from the rear to the front.

[0044] In this embodiment, the water supply port 135 is a circular through-hole that penetrates the water supply device 100 horizontally (in the front-to-back direction). Water supplied from the water supply tank 3 passes through the water supply port 135 and is supplied (replenished) to the liquid tank 7a (see Figure 4(a)).

[0045] The shut-off valve 136 is a component that is attracted toward the water supply port 135 by the first magnet 124, thereby closing the water supply port 135, and when the attractive force from the first magnet 124 decreases, it separates from the water supply port 135 and opens the water supply port 135. The shut-off valve 136 is a ferromagnetic component made of steel. The diameter of the shut-off valve 136 is set to be larger than the diameter of the O-ring 138. In addition, the shut-off valve 136 may be coated with a fluororesin or the like to prevent corrosion.

[0046] When the water supply port 135 is closed by the shut-off valve 136, a gap D1 is formed between the lowest point P1, which is the lowest part of the shut-off valve 136, and the bottom surface 134a of the lower part 132.

[0047] The regulating section 137 is formed such that, when the water supply port 135 is closed by the water shut-off valve 136, the uppermost point of the water shut-off valve 136 is in contact with it.

[0048] The O-ring 138 is a component that functions as a sealing material, deforming when pressed by the shut-off valve 136 when the shut-off valve 136 is attracted toward the water supply port 135, thereby creating a watertight (water-stopped) state for the water supply pipe 130. In this embodiment, the material of the O-ring 138 is fluororubber. The material of the O-ring 138 can be any material that is resistant to deterioration and corrosion by battery fluid. For example, in addition to fluororubber, nitrile rubber and fluororesin can be used. The diameter of the O-ring 138 is set to be larger than the inner diameter of the water supply port 135.

[0049] Next, the water supply and shut-off operations of the water supply device 100 will be explained with reference to Figures 3(c) and 4. Figure 3(c) is a partially enlarged cross-sectional view of the water supply device 100 in a state where the shut-off valve 136 is attracted to the rear side by the first magnet 124; Figure 4(a) is a cross-sectional view of the water supply device 100 in a state of insufficient water level where the float 120 is at its lower limit; Figure 4(b) is a cross-sectional view of the water supply device 100 in a state of appropriate water level where the water level (liquid surface S) is at the upper limit of the appropriate water level; and Figure 4(c) is a cross-sectional view of the water supply device 100 in a state of excess water level where the float 120 is at its upper limit (the float 120 is in the second position). Note that Figure 3(c) is a partially enlarged cross-sectional view of the water supply device 100 in the same part as Figure 3(b) (i.e., part IIIb). In Figure 4, a portion of the water supply device 100 in the front-to-back direction is omitted from the illustration (the same applies to water supply devices 200, 300, 400, and 500 in Figures 5 to 8).

[0050] Here, we define the state in which the battery fluid level is below the lower limit of the appropriate level as the under-level state, the state in which the battery fluid level is within the appropriate level range (from the lower limit to the upper limit of the appropriate level) as the appropriate level state, and the state in which the battery fluid level is above the upper limit of the appropriate level state as the over-level state. As shown in Figure 4(c), the state in which the upper end surface of the float 120 is in contact with the lower surface of the cap 112 (the state in which the float 120 is in the second position) is defined as the upper limit state within the over-level state. The inner surface of the counterbore hole 113b is marked with a scale in the vertical direction, and each state can be confirmed by the vertical positional relationship between the scale and the indicator part 123.

[0051] As shown in Figure 4(a), in the water replenishment device 100, when the float 120 is at its lower limit during a water level shortage, the upper end (upper tip) of the first magnet 124, which is installed on the level gauge 121, is located below the shut-off valve 136.

[0052] In the low water level state, the attractive force of the first magnet 124 is set to a magnitude that cannot resist the weight of the shut-off valve 136 (gravity acting on the shut-off valve 136) and thus cannot attract the shut-off valve 136. Therefore, in the low water level state, the shut-off valve 136 is separated from the water supply port 135 and positioned on the bottom surface 134a inside the water supply pipe 130. By separating the shut-off valve 136 from the water supply port 135 and opening the water supply port 135, water supplied from the water supply tank 3 passes through the water supply port 135 and is replenished in the liquid tank 7a.

[0053] The bottom surface 134a of the water supply pipe 130 slopes downward as it moves away from the water supply port 135 towards the front. This makes it easier to move the spherical shut-off valve 136 from the rear to the front on the bottom surface 134a, moving it horizontally (forward) away from the water supply port 135 and maintaining that distance. Therefore, when the water supplied from the water supply tank 3 passes through the water supply port 135 and is replenished in the liquid tank 7a, it becomes less likely that the shut-off valve 136 will be pushed back towards the water supply port 135 by the water flow. As a result, it becomes easier to maintain the open state of the water supply port 135, and water can be replenished stably.

[0054] Furthermore, when the water supply port 135 is closed by the shut-off valve 136, a gap D1 is formed between the lowest point P1, which is the lowest part of the shut-off valve 136, and the bottom surface 134a of the lower part 132. Therefore, when the shut-off valve 136 is separated from the water supply port 135 from that state, it is easier to move the shut-off valve 136 downward in the height direction from the water supply port 135 and maintain that separated position. Moreover, in order for the shut-off valve 136 to close the water supply port 135 from that state, it is necessary to lift the shut-off valve 136 upward in the height direction by the amount of the gap D1. Therefore, when the water supplied from the water tank 3 passes through the water inlet 135 and is replenished in the liquid tank 7a, even if the water flow of the supplied water causes the shut-off valve 136 to return to the horizontal side of the water inlet 135 (rear side), it is easier to maintain the open state of the water inlet 135, and water can be replenished stably.

[0055] When water is added to the liquid tank 7a in a low water level state, the float 120 rises as the water level rises. As the float 120 rises, the position of the upper end of the first magnet 124, which is installed on the level gauge 121, approaches the vertical position of the shut-off valve 136. As the distance between the vertical center of the first magnet 124 and the shut-off valve 136 decreases and the vertical position of the float 120 becomes higher than a predetermined position, the attractive force of the first magnet 124 acting on the shut-off valve 136 begins to attract the shut-off valve 136 against the weight of the shut-off valve 136.

[0056] The water stop valve 136, which has begun to be attracted by the first magnet 124, moves upward along the slope along the bottom surface 134a and closer to the water supply port 135, further reducing the distance from the vertical center of the first magnet 124. As a result, it becomes even easier for the valve to be attracted by the first magnet 124.

[0057] As shown in Figure 3(c), when the shut-off valve 136 approaches the water supply port 135 side due to the attractive force of the first magnet 124, it comes into contact with the O-ring 138. In this state, the position where the shut-off valve 136 and the O-ring 138 come into contact is located below the vertical center of the shut-off valve 136. If more water is added to the liquid tank 7a from this state, the float 120 rises (to the first position) and the first magnet 124 moves to an even higher position. When the shut-off valve 136 is attracted to the first magnet 124 to a sufficient extent that it can be held against its own weight, the shut-off valve 136 is lifted upward by a gap D1 as the first magnet 124 moves upward, while being attracted to the first magnet 124. That is, the shut-off valve 136 is lifted to a height that can close the water supply port 135. The shut-off valve 136 is attracted to the water inlet 135 side (rear side) by the first magnet 124, and the attractive force causes the shut-off valve 136 to press against the O-ring 138, thereby closing the water inlet 135 (see Figure 4(b)). In other words, the water inlet 135 is closed while the float 120 and the shut-off valve 136 are not mechanically connected. At this time, the uppermost point of the shut-off valve 136, which is the uppermost part, comes into contact with the lower surface of the regulating part 137.

[0058] As shown in Figure 4(b), when the water level (liquid surface S) of the water replenishment device 100 is at the upper limit of the appropriate water level, the upper surface of the indicator section 123 is flush with the upper surface 113c. At this time, the upper end of the first magnet 124 disposed on the level gauge 121 is located at approximately the same height as the shut-off valve 136.

[0059] When the water level is at the appropriate level, the water supply device 100 stops the water supply from the water tank 3 by closing the water supply port 135 with the shut-off valve 136. At this time, it can be confirmed through the light-transmitting cap 112 that the upper surface of the indicator part 123 is nearly flush with the upper surface 113c. Also, if a particular cell 7 is in a low water level state at this time, the indicator part 123 will be located below the upper surface 113c, so it can be determined that the water level is low by the scale on the inner surface of the counterbore hole 113b.

[0060] Here, the O-ring 138 may harden due to deterioration and become unable to deform sufficiently, or foreign matter may get caught between the water inlet 135 and the shut-off valve 136, resulting in insufficient closure of the water inlet 135. In this case, liquid leakage occurs even at the appropriate water level, and the water level rises further from the appropriate level. Although excess water is added to the liquid tank 7a above the appropriate water level, even in such a case (excessive water level), the water supply device 100 of this embodiment makes it difficult for liquid leakage from the water inlet 135 to occur any further.

[0061] If water is added in excess from the appropriate water level, the float 120 rises as the water level rises. As the float 120 rises, the position of the upper end of the first magnet 124, which is installed on the level gauge 121, moves above the shut-off valve 136.

[0062] At this time, as the float 120 moves upward, the shut-off valve 136 attempts to move upward as well. However, since the uppermost point of the shut-off valve 136 comes into contact with the lower surface of the regulating part 137, the shut-off valve 136 is restricted from moving upward from the contact position. As a result, even if the water level rises within the range of an excess water level condition, the shut-off valve 136 is less likely to come off the water supply port 135.

[0063] As shown in Figure 4(c), in the upper water level state (when the float 120 is in the second position), the water supply device 100 is configured such that the upper end of the first magnet 124, which is installed on the level gauge 121, is above the shut-off valve 136, and the vertical center of the first magnet 124 is below the shut-off valve 136.

[0064] In this embodiment, the distance between the vertical center of the first magnet 124 and the shut-off valve 136 is smallest when the vertical center of the first magnet 124 is at the same height as the shut-off valve 136. Since the front side of the first magnet 124 in the thickness direction (front-to-back direction) is set as the north pole and the rear side as the south pole, the smaller the distance from the center of the magnetic pole surface (in this embodiment, the front side of the first magnet 124), which is the magnetic pole (north or south pole) side, to the shut-off valve 136, the greater the attractive force with which the first magnet 124 attracts the shut-off valve 136. Therefore, the attractive force with which the first magnet 124 attracts the shut-off valve 136 is set to gradually increase as the float 120 moves upward when the vertical center of the first magnet 124 is below the shut-off valve 136, and to be largest when the vertical center is at the same height as the shut-off valve 136.

[0065] In the upper water level state, the upper end of the first magnet 124 is located above the shut-off valve 136, and its vertical center is located below the shut-off valve 136. Therefore, if water is added in excess of the appropriate water level state (considered an overwater level state), as the water level rises, the shut-off valve 136 approaches the vertical center of the first magnet 124. The smaller the distance between the vertical center of the first magnet 124 and the shut-off valve 136, the greater the force (attraction force) that the shut-off valve 136 receives from the entire first magnet 124. Thus, as the water level rises in the overwater level state, the force with which the first magnet 124 attracts the shut-off valve 136 can be increased. Therefore, even in the overwater level state, it is difficult to cause further leakage.

[0066] When the battery fluid in the fluid tank 7a decreases from an excess fluid level or an appropriate fluid level, the fluid level S of the water replenishment device 100 decreases. As the fluid level S decreases, the float 120 also decreases. When the float 120 decreases below the appropriate fluid level and the upper end of the first magnet 124 is positioned below the shut-off valve 136 (insufficient fluid level), the distance between the vertical center of the first magnet 124 and the shut-off valve 136 gradually increases as the float 120 decreases.

[0067] When the holding force of the first magnet 124, which holds the shut-off valve 136 against its own weight, can no longer withstand the weight of the shut-off valve 136, the shut-off valve 136 falls downward within the water supply pipe 130. As a result, the shut-off valve 136 is separated from the water supply port 135. Separated from the water supply port 135, the shut-off valve 136 falls to the bottom surface 134a and rolls forward on the downward-sloping bottom surface 134a. Since the shut-off valve 136 is separated from the water supply port 135, the water supply port 135 opens and water supply from the water supply port 135 begins. At this time, the water supply port 135 is opened with the float 120 and the shut-off valve 136 mechanically disconnected.

[0068] According to the water supply device 100 of the first embodiment, the water supply port 135 can be closed by the water stop valve 136, which is attracted to the water stop valve 136 by the first magnet 124, thereby stopping the supply of water from the water supply tank 3 to the liquid tank 7a of the cell 7. The water supply device 100 presses the water stop valve 136 against the water supply port 135 (O-ring 138) by the attractive force of the first magnet 124.

[0069] In the water supply device 100, the water supply port 135 is opened and closed with the float 120 and the shut-off valve 136 not mechanically connected. Therefore, in the structure for opening and closing the water supply port 135, a part for mechanically connecting the float 120 and the shut-off valve 136 is unnecessary. As a result, variations in the dimensional accuracy of each part involved in the opening and closing operation of the water supply port 135 (for example, the shut-off valve 136 and the first magnet 124) and the effects of snagging between parts can be reduced. Consequently, it becomes easier to open (supply water) and close (stop water) the water supply port 135 using the shut-off valve 136, and it becomes less likely to cause insufficient water supply due to delayed opening or non-opening of the water supply port 135, or liquid leakage due to the water supply port 135 not being closed.

[0070] In the water supply device 100 of the first embodiment, the cross-section of the hole 113a of the guide portion 113 is rectangular in shape and is slightly larger than the cross-section of the level gauge 121. Therefore, even if the level gauge 121 tries to rotate around an axis parallel to the vertical direction, the outer surface of the level gauge 121 comes into contact with the inner surface of the hole 113a, restricting rotation around the axis parallel to the vertical direction. Thus, the surface that the level gauge 121 faces relative to the water supply pipe 130 can be made to be approximately constant. As a result, the first magnet 124, which is arranged on the front (front) side of the level gauge 121, can always be positioned facing the water supply pipe 130 (shut-off valve 136). The magnitude of the attractive force that the first magnet 124 exerts on the shut-off valve 136 is correlated with the distance between the vertical center of the first magnet 124 and the shut-off valve 136. Therefore, it is easy to make the magnitude of the attractive force that the first magnet 124 exerts on the shut-off valve 136 approximately constant. Therefore, it becomes easier to maintain a stable, water-stopped state.

[0071] Next, with reference to Figure 5, the water replenishment device 200 in the second embodiment will be described. In the first embodiment described above, the case in which the float 120 is equipped with a first magnet 124 was described, but in the second embodiment, the case in which the float 220 is equipped with a second magnet 225 in addition to the first magnet 124 will be described.

[0072] Figure 5(a) is a cross-sectional view of the water replenishment device 200 of the second embodiment when the float 220 is at its lower limit in a low water level state, and Figure 5(b) is a cross-sectional view of the water replenishment device 200 when the water level (liquid surface S) is at the upper limit of the appropriate water level state. In Figures 5(a) and 5(b), in order to simplify the drawings, the hatching of the enlarged parts of the first magnet 124, the second magnet 225, and the shut-off valve 236 is omitted (the same applies to Figures 6 and 7). Note that parts that are the same as those described in the first embodiment are denoted by the same reference numerals and the following description is omitted (the same applies to Figures 6 to 9).

[0073] As shown in Figure 5, in the second embodiment, the water replenishment device 200 comprises a device body 110, a float 220 disposed within the device body 110 and configured to move up and down in accordance with the rise and fall of the liquid level S (water level) of the battery fluid in the liquid tank 7a, and a water replenishment pipe 230 disposed within the device body 110 and having a water replenishment port 235 formed therein.

[0074] The float 220 comprises a floating portion 122, a level gauge 121, and a marking portion 123 (not shown) that protrudes from the outer surface of the level gauge 121.

[0075] A first magnet 124 is positioned on the front (front) side of the lower end (the side connected to the floating portion 122) of the level gauge 121, and a second magnet 225 is positioned above the first magnet 124. In this embodiment, a level gauge 121 is molded with pre-formed recesses to accommodate the first magnet 124 and the second magnet 225, and the first magnet 124 and the second magnet 225 are bonded to these recesses.

[0076] The second magnet 225 is a flat, plate-shaped permanent magnet (a neodymium magnet in this embodiment) that extends in the vertical direction. In this embodiment, the second magnet 225 is configured such that its magnetic poles are opposite to those of the first magnet 124, with the front side in the thickness direction (front-to-back direction) set as the north pole and the rear side set as the south pole. At least the front surface of both the first magnet 124 and the second magnet 225 is coated with a fluororesin coating to improve corrosion resistance, sliding properties, and wear resistance.

[0077] The water supply pipe 230 is a tubular member for replenishing the liquid tank 7a with water supplied from the water supply tank 3. The water supply pipe 230 comprises an upper part 131 and a lower part 232 that is suspended from the center of the upper part 131 in the left-right direction.

[0078] The lower section 232 has a rectangular cross-section and comprises four side walls 233 extending in the vertical direction, and a bottom wall 234 connected to the lower ends of the four side walls 233 to form a bottom surface 234a. Furthermore, a plate-shaped water stop valve 236 is movably disposed inside the lower section 232.

[0079] A water inlet 235 is formed at the lower end of the rear side wall 233, opening to the inside of the main body 111 and to the liquid tank 7a. Above the upper end of the water inlet 235, a restricting portion 237 is formed connecting the two left and right side walls 233. A rectangular rubber packing 238 is provided on the inner surface of the side wall 233 along the water inlet 235. The bottom wall 234 has a substantially horizontal bottom surface 234a. In this embodiment, the water inlet 235 is a rectangular through-hole that penetrates the water supply device 200 in the horizontal direction (front-to-back direction).

[0080] The shut-off valve 236 is a component that closes the water supply port 235 by an attractive force acting toward it by the first magnet 124, and opens the water supply port 235 by a repulsive force acting toward it away from the water supply port 235 by the second magnet 225. The shut-off valve 236 is itself made of magnets. The magnetic pole of the shut-off valve 236 that faces the float 220 (the N pole in this embodiment) is set to be a different magnetic pole from the magnetic pole of the first magnet 124 that faces the shut-off valve 236, and to be the same as the magnetic pole of the second magnet 225 that faces the shut-off valve 236.

[0081] The shut-off valve 236 is configured so that each side is larger than each side of the rubber packing 238. The shut-off valve 236 is slidably positioned in the front-rear direction between the four side walls 233, the bottom wall 234, and the regulating portion 237. The shut-off valve 236 may be coated with a fluororesin or the like to prevent corrosion.

[0082] The rubber packing 238 is made of the same material and performs the same function as the O-ring 138 in the first embodiment. Each side of the rubber packing 238 is set to be larger than each side of the water inlet 235.

[0083] In the water replenishment device 200, when the float 220 is at its lower limit during a water level shortage (see Figure 5(a)), the vertical center of the second magnet 225, which is installed on the level gauge 121, is located at the vertical center of the shut-off valve 236.

[0084] The second magnet 225 is positioned such that the magnetic pole on the side facing the shut-off valve 236 is the same as the magnetic pole of the shut-off valve 236 that faces the second magnet 225. Therefore, in a low water level state, a repulsive force acts between the second magnet 225 and the shut-off valve 236. As a result, the shut-off valve 236 is moved away from the water supply port 235, the water supply port 235 is opened, and water supplied from the water supply tank 3 passes through the water supply port 235 and is replenished in the liquid tank 7a. In a low water level state, the water supply port 235 is opened due to the repulsive force from the second magnet 225 acting on the shut-off valve 236. That is, the water supply port 235 is opened when the float 220 and the shut-off valve 236 are mechanically disconnected.

[0085] When water is added to the liquid tank 7a in a low water level state, the float 220 rises as the water level rises. As the float 220 rises, the position of the upper end of the first magnet 124, which is installed on the level gauge 121, approaches the vertical position of the shut-off valve 236. As the distance between the vertical center of the first magnet 124 and the vertical center of the shut-off valve 236 decreases and the vertical position of the float 220 becomes higher than a predetermined position, the first magnet 124 acting on the shut-off valve 236 begins to attract the shut-off valve 236, overcoming the repulsive force of the second magnet 225 acting on the shut-off valve 236.

[0086] As the water stop valve 236 begins to be attracted by the first magnet 124, it moves closer to the water supply port 235 side, and the distance from the vertical center of the first magnet 124 becomes even smaller. As a result, it becomes even easier for the water stop valve 236 to be attracted by the first magnet 124.

[0087] As the shut-off valve 236 approaches the water supply port 235 side due to the attractive force of the first magnet 124, it comes into contact with the rubber packing 238. Since the shut-off valve 236 is attracted to the water supply port 235 side (rear side) by the first magnet 124, the attractive force causes the shut-off valve 236 to press against the rubber packing 238, closing the water supply port 235 (see Figure 5(b)). At this time, the water supply port 235 is closed with the float 220 and the shut-off valve 236 not mechanically connected. Note that the operation of the water supply device 200 in an overwater level state is the same as the operation of the water supply device 100 in an overwater level state, so the explanation is omitted.

[0088] When the battery fluid in the fluid tank 7a decreases from an excess fluid level or an appropriate fluid level, the float 220 is lowered as the fluid level S drops. When the float 220 is lowered below the appropriate fluid level and the lower end of the second magnet 225 is positioned below the vertical center of the shut-off valve 236 (insufficient fluid level), the distance between the vertical center of the second magnet 225 and the center of the shut-off valve 236 gradually decreases as the float 220 descends.

[0089] When the repulsive force acting on the shut-off valve 236 from the second magnet 225 becomes greater than the attractive force acting on the shut-off valve 236 from the first magnet 124, the shut-off valve 236 is separated from the water inlet 235 by the repulsive force acting on it from the second magnet 225. Separated from the water inlet 235, the shut-off valve 236 slides forward between the four side walls 233, the bottom wall 234, and the regulating section 237. As the shut-off valve 236 is separated from the water inlet 235, the water inlet 235 is opened and water supply from the water inlet 235 begins.

[0090] According to the water supply device 200 of the second embodiment, the water supply port 235 is opened and closed even when the float 220 and the shut-off valve 236 are not mechanically connected. This eliminates the need for a component to mechanically connect the float 220 and the shut-off valve 236 in the structure for opening and closing the water supply port 235. Therefore, variations in the dimensional accuracy of each component involved in the opening and closing operation of the water supply port 235 (for example, the shut-off valve 236, the first magnet 124, and the second magnet 225) and the effects of snagging between components can be reduced. As a result, it is easier to open (supply water) and close (stop water) the water supply port 235 using the shut-off valve 236, and it is less likely to cause insufficient water supply due to delayed opening or non-opening of the water supply port 235, or liquid leakage due to the water supply port 235 not being reliably closed.

[0091] Next, with reference to Figure 6, the water supply device 300 in the third embodiment will be described. In the second embodiment described above, the case in which the float 220 is positioned opposite the water supply port 235 of the water supply pipe 230 was described. In contrast, in the third embodiment, the case in which the float 320 is positioned on the opposite side from the direction opposite to the water supply port 235 of the water supply pipe 330 will be described.

[0092] Figure 6(a) is a cross-sectional view of the water replenishment device 300 of the third embodiment when the float 320 is at its lower limit in a low water level state, and Figure 6(b) is a cross-sectional view of the water replenishment device 300 when the water level (liquid surface S) is at the upper limit of the appropriate water level state. In addition to the parts that are the same as those described in the first embodiment, the parts that are the same as those described in the second embodiment are denoted by the same reference numerals and their descriptions are omitted below (the same applies to Figure 7).

[0093] As shown in Figure 6, the water replenishment device 300 comprises a device body 310 fixed to the liquid tank 7a, a float 320 disposed within the device body 310 and configured to move up and down in accordance with the rise and fall of the liquid level S (water level) of the battery fluid in the liquid tank 7a, and a water replenishment pipe 330 disposed within the device body 310 and having a water replenishment port 235 formed therein.

[0094] The device body 310 comprises a cylindrical main body portion 311 whose outer surface is fitted into the liquid port 7b (see Figure 2) of the cell 7, and a cap 112. The main body portion 311 is made of synthetic resin. The water supply device 300 also functions as a stopper to close the liquid port 7b due to the above configuration.

[0095] The main body portion 311 is provided with a hole 113a that penetrates in the vertical direction and a guide portion 313 that protrudes toward the center from the radially inner circumferential surface side of the main body portion 311. The guide portion 313 is configured identically to the guide portion 113 in the first and second embodiments, except that it is positioned on the front side of the main body portion 311.

[0096] The float 320 comprises a floating portion 122, a level gauge 121, and a marking portion 123. A third magnet 324 is disposed on the rear (rear) side of the lower end side (the side connected to the floating portion 122) of the level gauge 121, and a fourth magnet 325 is disposed above the third magnet 324. The float 320 of this embodiment is the float 220 of the second embodiment rotated 180° so that the front-rear direction is reversed. The third magnet 324 is configured identically to the first magnet 124 in the first and second embodiments, and the fourth magnet 325 is configured identically to the second magnet 225 in the second embodiment. Therefore, the third magnet 324 is set to have the rear side in the thickness direction as the south pole and the front side as the north pole, and the fourth magnet 325 is set to have the rear side in the thickness direction as the north pole and the front side as the south pole.

[0097] The water supply pipe 330 is configured identically to the water supply pipe 230 in the second embodiment, except that it is located behind the guide section 313. In the water supply device 300, when the float 320 is at its lower limit during a water level shortage (see Figure 6(a)), the vertical center of the fourth magnet 325, which is located on the level gauge 121, is positioned at the vertical center of the shut-off valve 236.

[0098] Since the magnetic pole of the fourth magnet 325 facing the shut-off valve 236 and the magnetic pole of the shut-off valve 236 facing the fourth magnet 325 are arranged to be different, an attractive force acts between the fourth magnet 325 and the shut-off valve 236 when the water level is low. As a result, the shut-off valve 236 moves away from the water supply port 235, the water supply port 235 is opened, and water supplied from the water supply tank 3 passes through the water supply port 235 and is replenished in the liquid tank 7a. When the water level is low, the water supply port 235 is opened by the attractive force from the fourth magnet 325 acting on the shut-off valve 236. That is, the water supply port 235 is opened when the float 320 and the shut-off valve 236 are not mechanically connected.

[0099] When water is added to the liquid tank 7a in a low water level state, the float 320 rises as the water level rises. As the float 320 rises, the position of the upper end of the third magnet 324, which is installed on the level gauge 121, approaches the vertical position of the shut-off valve 236. As the distance between the vertical center of the third magnet 324 and the vertical center of the shut-off valve 236 decreases and the vertical position of the float 320 becomes higher than a predetermined position, the shut-off valve 236 begins to repel the third magnet 324 due to the repulsive force acting between the shut-off valve 236 and the third magnet 324, which is resisting the attractive force of the fourth magnet 325 acting on the shut-off valve 236. The shut-off valve 236, which has begun to be repelled by the third magnet 324, moves closer to the water supply port 235.

[0100] As the shut-off valve 236 approaches the water supply port 235 side due to the repulsive force acting between it and the third magnet 324, it comes into contact with the rubber packing 238. The shut-off valve 236 is repelled by the third magnet 324 toward the water supply port 235 side (rear side), and this repulsive force causes the shut-off valve 236 to press against the rubber packing 238, closing the water supply port 235 (see Figure 6(b)). At this time, the water supply port 235 is closed with the float 320 and the shut-off valve 236 not mechanically connected. Note that the operation of the water supply device 300 in the excess water level state is the same as the operation of the water supply device 100 in the excess water level state, except that the force acting from the third magnet 324 on the shut-off valve 236 is a repulsive force, so the explanation is omitted.

[0101] When the battery fluid in the fluid tank 7a decreases from an excess fluid level or an appropriate fluid level, the float 320 is lowered as the fluid level S drops. When the float 320 is lowered below the appropriate fluid level and the lower end of the fourth magnet 325 is positioned below the vertical center of the shut-off valve 236 (insufficient fluid level), the distance between the vertical center of the fourth magnet 325 and the center of the shut-off valve 236 gradually decreases as the float 320 descends.

[0102] When the attractive force acting on the shut-off valve 236 from the fourth magnet 325 becomes greater than the repulsive force acting on the shut-off valve 236 from the third magnet 324, the shut-off valve 236 is separated from the water inlet 235 by the attractive force acting on it from the fourth magnet 325. Separated from the water inlet 235, the shut-off valve 236 slides forward between the four side walls 233, the bottom wall 234, and the regulating section 237. As the shut-off valve 236 is separated from the water inlet 235, the water inlet 235 is opened and water supply from the water inlet 235 begins.

[0103] According to the water supply device 300 of the third embodiment, the water supply port 235 is opened and closed even when the float 320 and the shut-off valve 236 are not mechanically connected. This eliminates the need for a component to mechanically connect the float 320 and the shut-off valve 236 in the structure for opening and closing the water supply port 235. Therefore, variations in the dimensional accuracy of each component involved in the opening and closing operation of the water supply port 235 (for example, the shut-off valve 236, the third magnet 324, and the fourth magnet 325) and the effects of snagging between components can be reduced. As a result, it is easier to open (supply water) and close (stop water) the water supply port 235 using the shut-off valve 236, and it is less likely to cause insufficient water supply due to delayed opening or non-opening of the water supply port 235, or liquid leakage due to the water supply port 235 not being reliably closed.

[0104] Next, with reference to Figure 7, the water supply device 400 in the fourth embodiment will be described. In the third embodiment described above, the case in which the float 320 is equipped with a fourth magnet 325 capable of attracting the shut-off valve 236 was described, but in contrast, the fourth embodiment will describe the case in which the fourth magnet 325 is not provided.

[0105] Figure 7(a) is a cross-sectional view of the water replenishment device 400 of the fourth embodiment when the float 420 is at its lower limit in a low water level state, and Figure 7(b) is a cross-sectional view of the water replenishment device 400 when the water level (liquid surface S) is at the upper limit of the appropriate water level state. In addition to the parts that are the same as those described in the first and second embodiments, the parts that are the same as those described in the third embodiment are denoted by the same reference numerals and their descriptions are omitted below.

[0106] As shown in Figure 7, the water replenishment device 400 comprises a device body 310, a float 420 disposed within the device body 310 and configured to move up and down in accordance with the rise and fall of the liquid level S (water level) of the battery fluid in the liquid tank 7a, and a water replenishment pipe 430 disposed within the device body 310 and having a water replenishment port 435 formed therein.

[0107] The float 420 comprises a floating portion 122, a level gauge 121, and a marking portion 123. A third magnet 324 is disposed on the rear side of the lower end of the level gauge 121 (the side connected to the floating portion 122). The float 420 of this embodiment is the float 320 of the third embodiment with the fourth magnet 325 omitted.

[0108] The water supply pipe 430 is configured identically to the water supply pipe 330 in the third embodiment, except for the configuration of the lower part 432. In the water supply device 400, when the float 320 is at its lower limit during a water level shortage (see Figure 7(a)), the upper end (upper tip) of the third magnet 324 disposed on the level gauge 121 is located below the shut-off valve 436.

[0109] The lower section 432 has a rectangular cross-section and comprises four side walls 433 extending vertically, and a bottom wall 434 connected to the lower ends of the four side walls 433 to form a bottom surface 434a. Furthermore, a rectangular plate-shaped water stop valve 436 is rotatably supported on the bottom wall 434.

[0110] A water supply port 435 is formed at the lower end of the rear side wall 433, opening to the inside of the main body 311 and to the liquid tank 7a. A rectangular rubber packing 438 is provided on the inner surface of the side wall 433 along the water supply port 435. In this embodiment, the water supply port 435 is a rectangular through-hole that penetrates the water supply device 400 in the horizontal direction (front-to-back direction).

[0111] A projection 433a is formed on the upper side wall 433 of the water supply port 435, projecting inward, and a shaft portion 439 is formed on the lower bottom wall 434 of the water supply port 435, which pivotally supports one end of the shut-off valve 436. The bottom surface 434a of the bottom wall 434 is parallel to the horizontal direction. A rising portion 437 is formed on the bottom surface 434a, projecting upward.

[0112] The shut-off valve 436 is a component that, due to the repulsive force acting toward the water supply port 435 by the third magnet 324, closes the water supply port 435, and then opens the water supply port 435 by moving away from it due to its own weight. The shut-off valve 436 is itself made of a magnet. When the water supply port 435 is closed by the shut-off valve 436, the magnetic pole of the shut-off valve 436 that faces the float 420 (the S pole in this embodiment) is set to be the same magnetic pole as the magnetic pole of the third magnet 324 that faces the shut-off valve 436. The shut-off valve 436 may be coated with a fluororesin or the like to prevent corrosion.

[0113] The shut-off valve 436 is set to have an outer diameter larger than the inner diameter of the rubber packing 438. The shut-off valve 436 is pivotally supported on the shaft portion 439 and is rotatable around an axis extending in the left-right direction of the shaft portion 439.

[0114] The riser portion 437 is the part that raises the other end of the shut-off valve 436 upward from the bottom surface 434a when the shut-off valve 436 is opening the water supply port 435. The distance from the shaft portion 439 to the riser portion 437 is made smaller than the longitudinal length of the shut-off valve 436. Because the riser portion 437 raises the shut-off valve 436 upward from the bottom surface 434a, when the repulsive force of the third magnet 324 acts on the shut-off valve 436, it is made easier to rotate the shut-off valve 436 in the direction of rotation towards the water supply port 435 around the axis of the shaft portion 439.

[0115] The rubber packing 438 is a component that has the same function as the O-ring 138 and is made of the same material as the O-ring 138. The inner shape of the rubber packing 438 is set to be larger than the inner shape of the water inlet 435.

[0116] The operation of the water supply device 400 in the fourth embodiment is the same as that of the water supply device 300 in the third embodiment, except for the operation in which the water supply port 435 is opened by the weight of the shut-off valve 436. Therefore, a description of the operation other than the opening of the water supply port 435 will be omitted.

[0117] In a low water level state, the repulsive force acting between the third magnet 324 and the shut-off valve 436 is set to a magnitude that cannot repel the shut-off valve 436 against its own weight (gravity acting on the shut-off valve 436) (i.e., the shut-off valve 436 cannot be rotated around the shaft 439 toward the water supply port 435). Therefore, in a low water level state, the shut-off valve 436 is separated from the water supply port 435 by its own weight. By separating the shut-off valve 436 from the water supply port 435 and opening the water supply port 435, water supplied from the water supply tank 3 passes through the water supply port 435 and is replenished in the liquid tank 7a.

[0118] According to the water supply device 400 of the fourth embodiment, the protruding portion 433a protrudes inward from the lower side wall 433 of the water supply port 435. Therefore, in the water-stopping state in which the shut-off valve 436 closes the water supply port 435, the other end of the shut-off valve 436 is inclined inward into the water supply pipe 430. As a result, the repulsive force acting between the third magnet 324 and the shut-off valve 436 becomes smaller than in the water-stopping state, and when the shut-off valve 436 tries to separate from the water supply port 435 (rubber packing 438), the weight of the shut-off valve 436 makes it easier to rotate the shut-off valve 436 around the axis of the shaft portion 439 (clockwise in Figure 7(a)). As a result, the water supply port 435 can be opened more easily.

[0119] When the battery fluid in the fluid tank 7a decreases from an excess fluid level or an appropriate fluid level, the float 420 is lowered as the fluid level S drops. When the float 420 is lowered below the appropriate fluid level and the upper end of the third magnet 324 is positioned below the shut-off valve 436 (insufficient fluid level), the distance between the vertical center of the third magnet 324 and the center of the shut-off valve 436 gradually increases as the float 420 descends.

[0120] When the repulsive force acting between the third magnet 324 and the shut-off valve 436 causes the holding force that holds the shut-off valve 436 against its own weight to become insufficient to support the weight of the shut-off valve 436, the shut-off valve 436 separates from the water supply port 435. As a result, the water supply port 435 opens, and water supply from the water supply port 435 begins.

[0121] In the fourth embodiment of the water supply device 400, the shut-off valve 436 is pivotally supported on the shaft portion 439, and the water supply port 435 is opened and closed by the rotation of the shut-off valve 436 around the axis of the shaft portion 439. This makes it more difficult to slide the shut-off valve 436 against the inner surface of the water supply pipe 430 compared to the third embodiment of the water supply device 300, in which the water supply port 235 is opened and closed by the free movement of a plate-shaped shut-off valve 236 toward the water supply port 235. Therefore, it is easier to operate the shut-off valve 436 between the bottom wall 434 and the side wall 433 on the water supply port 435 side. This makes it less susceptible to variations in the dimensional accuracy of each component involved in the opening and closing operation of the water supply port 435 (for example, the shut-off valve 436 and the third magnet 324) and the effects of snagging between components. As a result, the water supply port 435 can be easily opened (supplied) and closed (stopped) by the water stop valve 436, making it less likely for water supply to be insufficient due to delayed or non-opening of the water supply port 435, or for liquid leakage to occur due to the water supply port 435 not being reliably closed.

[0122] Next, with reference to Figure 8, the water replenishment device 500 in the fifth embodiment will be described. In the first embodiment described above, the case in which the float 120 operates only in the vertical direction was described, but in the fifth embodiment, the case in which the float 520 operates in the front-back direction in addition to the vertical direction will be described.

[0123] Figure 8(a) is a cross-sectional view of the water replenishment device 500 of the fifth embodiment when the float 520 is at its lower limit in a low water level state; Figure 8(b) is a cross-sectional view of the water replenishment device 500 when the water level (liquid surface S) is at the upper limit of the appropriate water level state; Figure 8(c) is a cross-sectional view of the water replenishment device 500 along the line VIIIc-VIIIc in Figure 8(a); and Figure 8(d) is a cross-sectional view of the water replenishment device 500 along the line VIIId-VIIId in Figure 8(b). In Figures 8(a) and 8(b), the hatching of the level gauge 121 and pin 525 is omitted in order to simplify the drawings.

[0124] As shown in Figure 8(a), in the fifth embodiment, the apparatus body 510 comprises a cylindrical body portion 511 whose outer surface is fitted into the liquid port 7b of the cell 7, and a cap 112 that can be opened and closed to cover the upper part of the body portion 511.

[0125] The main body portion 511 is provided with a hole 513a that penetrates in the vertical direction and a guide portion 513 that protrudes toward the center from the radially inner circumferential surface side of the main body portion 511. The hole 513a of the guide portion 513 is a portion that restricts the rotation of the float 520, which is inserted into the guide portion 513 so as to be able to move up and down and in the front and back directions, around an axis parallel to the vertical direction.

[0126] The cross-section of the guide portion 513 is rectangular. The hole 513a is an elongated hole that penetrates vertically and extends in the front-to-back direction, with a rectangular cross-section. The guide portion 513 comprises a front wall surface 513a1 that forms the front (front) side of the hole 513a, a rear wall surface 513a2 that forms the rear (back) side, and side wall surfaces 513a3 that connect the front wall surface 513a1 and the rear wall surface 513a2 and form the left and right sides of the hole 513a.

[0127] Each side wall surface 513a3 has a groove 513d formed thereon that is the same shape and in the same position, recessed in the left-right direction. The groove 513d comprises a first groove 513d1 extending upward from the lowest end of the groove 513d, a second groove 513d2 connected to the upper end of the first groove 513d1 and extending inclined forward and upward, and a third groove 513d3 connected to the upper end of the second groove 513d2 and extending inclined forward and upward. The angle at which the second groove 513d2 inclins forward is set to be greater than the angle at which the third groove 513d3 inclins forward.

[0128] The float 520 comprises a floating portion 122, a level gauge 121, and a pin 525 fitted into the level gauge 121. The floating portion 122, the level gauge 121, and the pin 525 are made of synthetic resin.

[0129] The level gauge 121 is a rectangle with a width smaller than the distance between opposing side walls 513a3 of the hole 513a. The level gauge 121 is inserted into the hole 513a so as to be slidable in the vertical and horizontal directions. The pin 525 is a cylindrical member that penetrates the level gauge 121 in the horizontal direction. The pin 525 is slidably fitted into the groove 513d.

[0130] In the water replenishment device 500, when the float 520 is at its lower limit during a water level shortage (see Figure 5(a)), that is, when the pin 525 is in contact with the lower end of the first groove 513d1, the upper end of the first magnet 124 disposed on the level gauge 121 is located below the shut-off valve 136.

[0131] When water is added to the liquid tank 7a in an underwater water level state, the float 520 rises as the water level rises, and the pin 525 is positioned at the upper end of the first groove 513d1. As the float 520 rises, the vertical position of the upper end of the first magnet 124, which is installed on the level gauge 121, approaches the vertical position of the shut-off valve 136. When the pin 525 is positioned at the upper end of the first groove 513d1, the first magnet 124 and the shut-off valve 136 are separated in the front-rear direction, so the shut-off valve 136 is not attracted by the attractive force of the first magnet 124.

[0132] As more water is added to the liquid tank 7a from this state, the float 520 rises, and the pin 525 slides along the second groove 513d2 and is guided forward. At this time, the distance between the vertical center of the first magnet 124 and the shut-off valve 136 decreases, and when the vertical position of the float 520 becomes higher than a predetermined position, the attractive force of the first magnet 124 acting on the shut-off valve 136 begins to attract the shut-off valve 136 against its own weight. As the float 520 rises further from the position where the shut-off valve 136 begins to be attracted, the shut-off valve 136 is lifted upward in the height direction by the gap D1 while being attracted to the first magnet 124. When the float 520 is in this position (first position), the shut-off valve 136 is attracted to the water inlet 135 side (rear side) by the first magnet 124, pressing the O-ring 138 and closing the water inlet 135 (see Figure 8(b)).

[0133] As shown in Figure 8(b), when the water level (liquid surface S) of the water supply device 500 is at the upper limit of the appropriate water level, the pin 525 is located at the boundary between the second groove 513d2 and the third groove 513d3 (see Figure 8(d)). At this time, the upper end of the first magnet 124, which is installed on the level gauge 121, is located at approximately the same height as the shut-off valve 136. When the water level is appropriate, the shut-off valve 136 closes the water supply port 135, thus stopping the supply of water from the water tank 3 (shutting off the water).

[0134] The upper surface of the side wall 513a3 is marked with an area where the tip of the level gauge 121 is located when the water level is within the appropriate range. Therefore, by visually confirming that the upper end of the level gauge 121 is located within that area through the light-transmitting cap 112, it is possible to determine that the water level is within the appropriate range.

[0135] Here, we will explain how leakage from the water inlet 135 is unlikely to occur even in an overwater level state. When water is added in excess from the appropriate water level state, the float 520 rises as the water level rises, and the pin 525 slides in the third groove 513d3 and is guided forward. At this time, the distance between the vertical center of the first magnet 124 and the shut-off valve 136 becomes even smaller, and the attractive force of the first magnet 124 acting on the shut-off valve 136 becomes even greater than in the appropriate water level state. Since the shut-off valve 136 is attracted to the water inlet 135 side (rear side) by the first magnet 124 with an attractive force greater than in the appropriate water level state, it can press the O-ring 138 and make it easier to further close the water inlet 135.

[0136] When the battery fluid in the fluid tank 7a decreases from an excessive or appropriate level, the fluid level S of the fluid replenishment device 500 decreases. As the fluid level S decreases, the float 520 also decreases, and the pin 525 is guided into the third groove 513d3 and the second groove 513d2, causing the float 520 to move to the rear. When the float 520 is lowered below the appropriate level, and the upper end of the first magnet 124 is positioned below the shut-off valve 136, the distance between the vertical center of the first magnet 124 and the shut-off valve 136 gradually increases as the float 520 decreases.

[0137] When the holding force of the first magnet 124, which holds the shut-off valve 136 against its own weight, can no longer withstand the weight of the shut-off valve 136, the shut-off valve 136 falls downward within the water supply pipe 130. As a result, the shut-off valve 136 is separated from the water supply port 135. Since the shut-off valve 136 is separated from the water supply port 135, the water supply port 135 opens and water supply from the water supply port 135 begins.

[0138] According to the water supply device 500 of the fifth embodiment, as the float 520 moves up and down, the pin 525 slides along the second groove 513d2 and is guided forward or backward, so that the distance between the first magnet 124 and the shut-off valve 136 in the front-rear direction can be made smaller or larger. Therefore, the attractive force with which the first magnet 124 attracts the shut-off valve 136 can be reliably changed. As a result, the opening and closing of the water supply port 135 (O-ring 138) by the shut-off valve 136 in accordance with the up and down movement of the float 520 can be reliably achieved.

[0139] According to the water supply device 500 of the fifth embodiment, even when the float 520 rises in an excess water level state, the pin 525 slides on the third groove 513d3 and is guided forward, so that the force with which the first magnet 124 attracts the shut-off valve 136 can be made even greater than in the appropriate water level state. Therefore, the force that closes the water supply port 135 (O-ring 138) with the shut-off valve 136 can be made greater. Therefore, it is made even less likely for liquid to leak from the water supply port 135.

[0140] Although the present invention has been described above based on embodiments, it can be easily inferred that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention.

[0141] In the embodiments described above, the battery 1 was described as being used in industrial vehicles such as automated guided vehicles, but the battery 1 may also be used in industrial vehicles such as forklifts or general vehicles such as automobiles.

[0142] In the embodiments described above, the case in which the battery 1 has 24 cells 7 was explained, but the number of cells 7 in the battery 1 is not limited to this. The battery 1 may have multiple or single cells 7 other than 24.

[0143] In the embodiments described above, the level gauge 121 was described as having a rectangular cross-section (transverse plane) when cut by a plane perpendicular to the vertical direction. However, the cross-section of the level gauge 121 may also be elliptical or polygonal.

[0144] In the embodiments described above, the magnets of floats 120, 220, 320, 420, and 520 (the first magnet 124, the second magnet 225, the third magnet 324, and the fourth magnet 325) were described as being flat plates of constant thickness. However, each magnet may be shaped such that its thickness increases as it goes downwards, or each magnet may be cylindrical, cylindrical, truncated cone, or annular with respect to the center of the level gauge 121.

[0145] In the embodiments described above, the water supply devices 100, 200, 300, 400, and 500 were described in a case where they did not have a means for separating the shut-off valves 136, 236, and 436 from the water supply ports 135, 235, and 435. However, the water supply devices 100, 200, 300, 400, and 500 may also be equipped with a means for separating. In this case, the means for separating may consist of a spring that biases the shut-off valves 136, 236, and 436 toward the direction away from the water supply ports 135, 235, and 435 (forward), or the function of the means for separating may be provided by an O-ring 138 or rubber packings 238, 438. The force exerted by the separation means to separate the shut-off valves 136, 236, and 436 is set to be smaller than the magnetic force (attraction or repulsion) acting on the shut-off valves 136, 236, and 436 from the first magnet 124 or the third magnet 324.

[0146] In the embodiments described above, the case in which an O-ring 138 or rubber packing 238, 438 is arranged along the water inlet 135, 235, 435 has been described, but a rubber-like cylinder may be fitted inside the inner circumferential surface of the water inlet 135, 235, 435. In this case, the water inlet 235, 435 in the second, third, and fourth embodiments are circular in shape, and the shut-off valves 236, 436 are hemispherical in shape so that at least a part of the surface facing the water inlet 235, 435 is fitted into the water inlet 235, 435.

[0147] In each of the above embodiments, the water replenishment devices 100, 200, 300, 400, and 500 were described in a state of excess water level where the vertical center of the first magnet 124 or the third magnet 324 is below the shut-off valves 136, 236, and 436. As the water level rises, the distance between the vertical center of the first magnet 124 or the third magnet 324 and the shut-off valves 136, 236, and 436 decreases, and the force with which the first magnet 124 or the third magnet 324 attracts or repels the shut-off valves 136, 236, and 436 increases. In contrast, the water replenishment devices 100, 200, 300, 400, and 500 may be configured such that, in an excess water level state where the vertical center of the first magnet 124 or the third magnet 324 is below the shut-off valves 136, 236, and 436, the magnitude of the force with which the first magnet 124 or the third magnet 324 attracts or repels the shut-off valves 136, 236, and 436 remains approximately constant even as the water level rises.

[0148] In this case, in an excess water level state, the first magnet 124 or the third magnet 324 is set so that its thickness becomes thinner towards the center in the vertical direction, or its central part in the vertical direction is curved towards the rear, so that the magnitude of the force that attracts or repels the water stop valves 136, 236, 436 remains approximately constant even when the water level rises.

[0149] In the first and fifth embodiments described above, the shut-off valve 136 was described as being spherical, but the shut-off valve 136 may also be conical or frustoconical. In this case, the water inlet 135 and the O-ring 138 are formed in a circular shape, the bottom surface of the conical or frustoconical shut-off valve 136 is set to be larger than the inner diameter of the water inlet 135, and the bottom surface 134a is a plane perpendicular to the vertical direction of the water supply device 100,500, or a surface that slopes downward as it moves away from the water inlet 135.

[0150] Furthermore, for example, the shut-off valve 136 may be cylindrical. This form will be described as the first modified example (water supply device 600) with reference to Figures 9(a) and 9(b). Figure 9(a) is a partial cross-sectional view of the water supply device 600 in the first modified example, and Figure 9(b) is a partial cross-sectional view of the water supply device 600 along the line IXb-IXb in Figure 9(a). Note that Figure 9(a) shows a cross-section corresponding to that in Figure 3(b).

[0151] As shown in Figures 9(a) and 9(b), the water supply device 600 includes a water supply pipe 630 in place of the water supply pipe 130 in the first and fifth embodiments. The water supply pipe 630 comprises an upper part 131 and a lower part 632 that is suspended from the center of the upper part 131 in the left-right direction. The lower part 632 has a rectangular cross-section and comprises four side walls 633 that extend in the vertical direction and a bottom wall 134 that is connected to the lower ends of the four side walls 633 and forms a bottom surface 134a. Furthermore, a cylindrical water stop valve 636 is disposed inside the lower part 632 so as to be rotatable on the bottom surface 134a.

[0152] A protruding curved portion 633a is formed at the lower end of the rear side wall 633, which protrudes to the rear and has a circular arc cross-section. A water supply port 635 is formed in this protruding curved portion 633a, which opens to the inside of the main body 111 and to the liquid tank 7a. A roughly rectangular rubber packing 638 is disposed on the inner surface of the protruding curved portion 633a, along the inner surface of the protruding curved portion 633a.

[0153] In this embodiment, the water supply port 635 is a rectangular through-hole that penetrates the water supply device 600 horizontally (front-to-back direction). The shut-off valve 636 is made of the same material as the shut-off valve 136. The diameter of the shut-off valve 636 is set to be approximately the same as the diameter of the rubber packing 638 (diameter of the arc portion), and its length in the left-to-right direction is set to be greater than the length of the rubber packing 638 in the left-to-right direction. In addition, the length of the shut-off valve 636 in the left-to-right direction is set to be slightly less than the distance between the left-to-right side walls 633 facing each other.

[0154] The rubber packing 638 is a component that has the same function as the O-ring 138 and is made of the same material as the O-ring 138. The inner shape of the rubber packing 638 is set to be larger than the inner shape of the water inlet 635.

[0155] According to the water supply device 600, since the shut-off valve 636 is cylindrical, its mass can be made larger than that of a spherical shut-off valve of the same radius. Therefore, when attempting to separate the shut-off valve 636 from the water supply port 635 in a low water level condition, it is made easier to separate the shut-off valve 636 from the water supply port 635.

[0156] In the first and fifth embodiments described above, the case in which the bottom surface 134a slopes downward as it moves away from the water supply port 135 was explained, but the bottom surface 134a may also be a plane perpendicular to the vertical direction.

[0157] In the first and fifth embodiments described above, the case in which a gap D1 is formed between the lowest end of the shut-off valve 136 and the bottom surface 134a when the water supply port 135 is closed by the shut-off valve 136 was described, but it is also possible that no gap D1 is formed.

[0158] In the second, third, and fourth embodiments described above, the case in which all of the shut-off valves 236, 436 are magnets was explained, but it is also possible for only a part of the shut-off valves 236, 436 to be magnets.

[0159] In the third and fourth embodiments described above, the third magnet 324 and the fourth magnet 325 were described as being configured identically to the first magnet 124 and the second magnet 225. However, the magnets may differ from the first magnet 124 and the second magnet 225 in terms of length, thickness, or shape.

[0160] In the fourth embodiment described above, the shut-off valve 436 is pivotally supported on the inner surface side of the water supply pipe 430. However, the shut-off valve 436 may also be pivotally supported on the outer surface side of the water supply pipe 730. In this case, the water supply port 435 opens on the front (front) side of the water supply pipe 730. This form will be described as a second modified example (water supply device 700) with reference to Figure 9(c). Figure 9(c) is a partial cross-sectional view of the water supply device 700 in the second modified example. Note that parts that are the same as those described in the water supply device 400 are denoted by the same reference numerals and their descriptions are omitted below.

[0161] The lower part 732 of the water supply pipe 730 of the water supply device 700 is provided with an overhang 740 that extends forward and outward from the side wall 733 on the side opposite (front) to the side facing the float 120. The front side wall 733 is provided with a recess 733b that is recessed to the rear. The water supply port 435, a projection 433a, and a rubber packing 438 are disposed in the recess 733b of the side wall 733, and the overhang 740 is provided with a rising portion 437 and a shaft portion 439. The shut-off valve 436 is pivotally supported on the shaft portion 439 and is capable of opening and closing the water supply port 435. In this case, a structure that closes the water supply port 435 by the shut-off valve 436 can be provided on the outer surface of the water supply pipe 730, so that structure can be added after the water supply pipe 730 has been manufactured. Therefore, the water supply device 700 can be easily manufactured.

[0162] In the fifth embodiment described above, the water replenishment device 500 is provided with a pin 525 and a groove 513d as guide means for reducing or increasing the distance between the first magnet 124 and the shut-off valve 136 in the front-rear direction. However, the water replenishment device 500 may also be provided with a bent portion formed by curving or bending the lower side of the level gauge 121 toward the rear, instead of the pin 525 and groove 513d, and the shape of the main body portion 511 (guide portion 513) is formed so that the float 520 is guided back and forth along the shape of the bent portion. [Explanation of Symbols]

[0163] 7a Liquid tank (case) 100,200,300,400,500,600,700 Water refilling device 110,310,510 Main unit of the device 113a, 513a Holes (rotation restricting means) 120, 220, 320, 420, 520 floats 121 Level gauge (pillar section) 124 The First Magnet 130,230,330,430,630,730 Water supply pipe 134a Bottom 135, 235, 435, 635 Water supply inlets 136,236,436,636 Water stop valve 225 The second magnet 324 The Third Magnet 325 The Fourth Magnet D1 Gap

Claims

1. A water replenishment device comprising: a device body disposed in a case filled with liquid; a float disposed in the device body and configured to move up and down in accordance with the water level of the liquid filled in the case; and a tubular water replenishment pipe disposed in the device body and having a water replenishment port opening into the case, for replenishing water to the liquid filled in the case, The water supply pipe is equipped with a shut-off valve configured to open and close the water supply port, The float is equipped with a first magnet configured to attract the water stop valve by magnetic force, The water supply port is located between the first magnet and the shut-off valve in a top view of the main body of the device. The water supply device is characterized in that the first magnet is positioned so as the float rises, it approaches the shut-off valve and moves away from it as the float descends, and by approaching the shut-off valve, it applies an attractive force to the shut-off valve in a direction toward the water supply port, thereby closing the water supply port.

2. The shut-off valve is movably disposed within the internal space of the water supply pipe, The water supply device according to claim 1, characterized in that a gap is formed between the bottom surface of the water supply pipe and the lowest end of the water stop valve when the water stop valve is in a water-stopping state that closes the water supply port.

3. The bottom surface of the water supply pipe is sloped downward as it moves away horizontally from the water supply port. The water supply device according to claim 1 or 2, characterized in that the shut-off valve has a circular or ring-shaped cross-section when cut by a plane perpendicular to the rotating axis that rolls across the bottom surface of the water supply pipe, and the bottom surface of the water supply pipe is configured to roll.

4. The float comprises a second magnet positioned above the first magnet and having its magnetic poles facing opposite directions from the first magnet. The water supply port is located between the second magnet and the shut-off valve when viewed from above the main body of the device. The aforementioned water stop valve is composed of a magnet in at least part of it. The water supply device according to claim 1, wherein the second magnet is positioned so as the float rises, it moves away from the shut-off valve and so as the float descends, and the magnet moves towards the shut-off valve and acts a repulsive force toward the shut-off valve that moves away from the water supply port, thereby opening the water supply port.

5. A water replenishment device comprising: a device body disposed in a case filled with liquid; a float disposed in the device body and configured to move up and down in accordance with the water level of the liquid filled in the case; and a tubular water replenishment pipe disposed in the device body and having a water replenishment port opening into the case, for replenishing water to the liquid filled in the case, The water supply pipe is configured to open and close the water supply port and includes a shut-off valve that is at least partly made of a magnet. The float is equipped with a third magnet configured to repel the water shut-off valve by magnetic force, The water supply port is located on the opposite side of the third magnet from the water shut-off valve when viewed from above the main body of the device, The water supply device is characterized in that the third magnet is positioned so as the float rises, it approaches the shut-off valve and moves away from it as the float descends, and closes the water supply port by acting a repulsive force on the shut-off valve in a direction toward the water supply port as it approaches the shut-off valve.

6. The float comprises a fourth magnet positioned above the third magnet and having its magnetic poles facing opposite directions from the third magnet. The water supply port is located on the opposite side of the fourth magnet from the water shut-off valve when viewed from above the main body of the device, The water supply device according to claim 5, wherein the fourth magnet is positioned so as the float rises, it moves away from the shut-off valve and so as the float descends, and the magnet acts as an attractive force on the shut-off valve, moving away from the water supply port, thereby opening the water supply port.

7. The water supply device according to claim 1 or 5, characterized in that the float is configured to be able to rise to a second position above a first position in which the water stop valve can close the water supply port due to the magnetic force acting on the water stop valve from the first magnet or the third magnet.

8. The water replenishment device according to claim 1 or 5, characterized in that the device body is provided with rotation restricting means for restricting the rotation of the float about an axis extending in the vertical direction.

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