JP7585752B2 - Flush toilet - Google Patents

Description

The disclosed embodiment relates to a flush toilet.

Conventionally, flush toilets that use flush water to clean the toilet body are known to be equipped with a pump that supplies flush water stored in a flush water tank to the toilet body. In such flush toilets, if the pump is operated when there is no flush water in the flush water tank, there is a risk that the pump's sealing structure (mechanical seal) will be damaged, causing water leakage, and otherwise adversely affecting pump performance.

For this reason, for example, some flushing machines are equipped with float switches at the top and bottom of the flushing water tank to detect the water level in the tank, and stop the pump when the float switch at the bottom of the flushing water tank detects a predetermined water level (see, for example, Patent Document 1).

In addition, for example, the water resistance that the pump experiences changes depending on whether there is cleaning water in the cleaning water tank or not, resulting in a difference in the value of the current flowing through the pump. Some pumps stop when it is determined that there is no cleaning water in the cleaning water tank due to the difference in the current value caused by such pump characteristics (for example, see Patent Document 2).

JP 2009-2075 A JP 2001-342989 A

However, among the conventional technologies mentioned above, those using upper and lower float switches are not preferable in terms of cost and miniaturization of the flush water tank because they have two float switches that are water level detection sensors.

In addition, devices that use differences in current values due to pump characteristics may erroneously detect the presence or absence of cleaning water in the cleaning water tank due to disturbances such as the amount of water in the cleaning water tank when the pump is running, the motor temperature, and individual variations in pump characteristics.

In addition, devices that utilize differences in current values due to pump characteristics compare the current value flowing through the pump with a threshold value to determine whether or not there is cleaning water in the cleaning water tank. When there is cleaning water in the cleaning water tank, the current value when the pump is rotated at a specified rotation speed or higher will always be above the threshold value when the threshold value is first set, so it can correctly determine that there is cleaning water. However, if the current value changes due to deterioration over time, it will be determined that there is no cleaning water. Specifically, the current value tends to gradually decrease over the course of years, for example. As a result, even when there is cleaning water, it will be determined that there is no cleaning water, and the pump will be stopped.

One aspect of the embodiment aims to provide a flush toilet that can accurately detect the presence or absence of flush water in the flush water tank while reducing the number of water level detection sensors.

A flush toilet according to one aspect of the embodiment is a flush toilet that is flushed with flush water, and is equipped with a toilet body, a flush water tank that stores flush water, a water supply unit that supplies flush water to the flush water tank, a pump that supplies flush water stored in the flush water tank to the toilet body, a control unit that controls the operation of the pump, a current value detection means that measures the value of current flowing through the pump, and a water level detection means that detects the water level in the flush water tank, and the control unit performs a first determination to determine the presence or absence of flush water in the flush water tank by comparing the water level detected by the water level detection means with a predetermined water level, and a second determination to determine the presence or absence of flush water in the flush water tank by comparing the current value measured by the current value detection means with a threshold value, and performs an abnormality determination of the threshold value based on the result of the first determination and the result of the second determination.

With this configuration, the water level (actual water level) in the flush water tank is detected by the water level detection means, and the presence or absence of flush water (water present/water absent) in the flush water tank is detected by the current value (pump current value) flowing through the pump, so the number of water level detection sensors such as float switches can be reduced. In addition, since the threshold abnormality determination is performed based on the judgment result of the first judgment, i.e., the water level in the flush water tank detected by the water level detection means, and the judgment result of the second judgment, i.e., the judgment result of whether water is present or absent obtained by comparing the pump current value with the threshold, erroneous detection of water presence/absence due to threshold abnormality can be suppressed, and water presence/absence detection can be performed with high accuracy. As a result, water presence/absence detection can be performed with high accuracy while reducing the number of water level detection sensors such as float switches.

The flush toilet described above is also characterized in that, in the first determination, the control unit starts toilet flushing when the water level is higher than the predetermined water level, and in the second determination, if the current value is lower than the threshold value, it determines that the threshold value is abnormal.

With this configuration, if the toilet flush is started when there is sufficient flush water in the flush water tank based on the water level (actual water level) detected by the water level detection means, but the determination result using the current value detection means is a water-absence determination, there is a high possibility that the current value detection means has made an erroneous determination. For this reason, if the pump current value is lower than the threshold in the second determination after the first determination, it is determined that the threshold is abnormal, making it possible to detect that the current threshold is abnormal.

Furthermore, in the flush toilet described above, the control unit is characterized in that, in the second judgment, if the current value is lower than the threshold value, the control unit supplies flush water to the flush water tank via the water supply unit, and if the time it takes for the water level detection means to detect the full water level is shorter than a predetermined time, it judges that an abnormality has occurred in the threshold value.

With this configuration, if the time it takes for the water level in the flush water tank to reach the full water level after the current value detection means has determined that there is no water, is shorter than a predetermined time (the time it takes for the flush water tank to become full after the toilet is flushed), it is determined that the current value detection means has not correctly determined whether or not there is flush water in the flush water tank, and an abnormality in the threshold is detected. This makes it possible to detect that the current threshold is abnormal.

The flush toilet described above further comprises a toilet flushing reception means for receiving toilet flushing operations from the user, and a limiting means for limiting input from the toilet flushing reception means during the period from when the toilet flushing starts until a predetermined condition is met, and the control unit is characterized in that, when the toilet flushing starts when the water level is lower than the predetermined water level in the first determination, and when the current value is higher than the threshold value in the second determination, it determines that an abnormality has occurred in the threshold value if the toilet flushing reception means receives a toilet flushing operation during the period when the limiting means is limiting input from the toilet flushing reception means.

With this configuration, after the current value detection means has determined that there is water, if the user's toilet flush operation is detected during the period in which the restriction means is restricting input from the toilet flush reception means, it is possible to determine that flush water is not flowing, for example, since it is presumed that the user will perform the toilet flush operation multiple times because flush water is not flowing, and it is possible to detect that the current threshold value is abnormal.

Furthermore, in the flush toilet described above, when the control unit determines that the threshold is abnormal, it executes a toilet flush and resets a new threshold according to the current value measured by the current value detection means associated with the toilet flush.

With this configuration, if an abnormality in the threshold is detected, a new threshold is reset according to the current pump current value, thereby preventing future false detections.

According to one aspect of the embodiment, the number of water level detection sensors can be reduced while accurately detecting the presence or absence of flush water in the flush water tank.

FIG. 1 is a diagram showing the general configuration of a flush toilet according to an embodiment. FIG. 2 is a diagram showing the overall configuration of a flush toilet. FIG. 3 is a diagram showing pump current values with and without water. FIG. 4 is an explanatory diagram of erroneous detection of water presence/absence. FIG. 5 is a flowchart illustrating an example of a processing procedure for controlling abnormality determination of a threshold value. FIG. 6 is a flowchart showing another example (part 1) of the processing procedure of the control for determining an abnormality in the threshold value. FIG. 7 is a flowchart showing another example (part 2) of the processing procedure of the control for determining an abnormality in the threshold value.

Below, an embodiment of the flush toilet disclosed in this application will be described in detail with reference to the attached drawings. Note that the present invention is not limited to the embodiment shown below.

First, referring to FIG. 1, an overview of the configuration of a flush toilet 1 according to an embodiment will be described. FIG. 1 is a diagram showing the overview of the configuration of a flush toilet 1 according to an embodiment. Note that FIG. 1 shows the flush toilet 1 in schematic form.

As shown in FIG. 1, the flush toilet 1 comprises a toilet body 10, a flush water tank 20, a water supply unit 40, a pump 50, and a control unit 60.

The toilet body 10 includes a rim water spout section 15 and a rim water conduit 16. The rim water spout section 15 is, for example, a water outlet that spouts flushing water into the bowl section 11 (see FIG. 2). The rim water conduit 16 is a flow path that circulates flushing water to the rim water spout section 15.

The cleaning water tank 20 stores cleaning water. The cleaning water tank 20 stores cleaning water supplied from a water supply source via a water supply line 41, for example. A water level detection means 30 is also provided in the cleaning water tank 20. The water level detection means 30 detects the water level of the cleaning water stored in the cleaning water tank 20.

The water supply unit 40 is, for example, an on-off valve provided in the water supply passage 41. The water supply unit 40 opens and closes the water supply passage 41 while the pump 50, described below, is operating, depending on the water level in the flush water tank 20. For example, when the water level in the flush water tank 20 falls below the full water level W0, that is, when a toilet flush starts and the pump 50 is operating, the water supply unit 40 opens and supplies flush water to the flush water tank 20. When the water level in the flush water tank 20 reaches the full water level W0, the water supply unit 40 closes and stops the supply of flush water to the flush water tank 20.

In this way, the flush toilet 1 is configured to supply water from the water source to the flush water tank 20 and replenish flush water while the toilet is being flushed (while the pump 50 is running). This allows the toilet to be flushed while flush water is being replenished, so the volume of the flush water tank 20 can be reduced, allowing for a more compact design.

The pump 50 pressurizes the flushing water in the flushing water tank 20. Specifically, the pump 50 pressurizes the flushing water stored in the flushing water tank 20 by drawing it in through the intake passage 51 from the intake port 51a disposed in the flushing water tank 20. The pump 50 discharges the pressurized flushing water through the discharge passage 52 to the rim water channel 16.

The control unit 60 controls the operation of the pump 50. The control unit 60 controls the operation of the pump 50 to supply flushing water to the toilet body 10. In other words, the control unit 60 controls the operation of the pump 50 to flush the toilet.

The flush toilet 1 also includes a current value detection means 70. The current value detection means 70 measures the value of the current flowing through the pump 50 while the pump 50 is operating.

However, in the case of a flush toilet 1 like this, which supplies flush water pressurized by a pump 50, if the pump 50 is driven when there is no flush water in the flush water tank 20, i.e., if the pump 50 is run dry, as described above, there is a risk that the pump performance will be adversely affected, for example, the sealing structure (mechanical seal) of the pump 50 will be damaged, causing water leakage.

For this reason, in this embodiment, the control unit 60 detects the presence or absence of cleaning water in the cleaning water tank 20 (hereinafter referred to as "water presence/absence detection"). The control unit 60 also detects the presence or absence of water using the value of the current flowing through the pump 50 measured by the current value detection means 70 (hereinafter referred to as "pump current value"). The control unit 60 determines the presence or absence of cleaning water in the cleaning water tank 20 based on the pump current value.

Next, the overall configuration of the flush toilet 1 will be described in detail with reference to Figure 2. Figure 2 is a diagram showing the overall configuration of the flush toilet 1. Note that Figure 2 also shows the flush toilet 1 in a schematic manner, just like Figure 1.

As shown in FIG. 2, the toilet body 10 of the flush toilet 1 is made of, for example, ceramic. The toilet body 10 comprises a bowl portion 11 and a drain trap pipe 12. Note that in FIG. 2, in order to simplify the illustration, some components of the toilet body 10, such as the toilet seat and the toilet lid that covers the toilet seat, are not shown. Also, while FIG. 2 shows a floor-standing toilet body 10 as an example, this is not limited to this and may be, for example, a wall-mounted toilet body.

The bowl portion 11 is connected to the above-mentioned rim water conduit 16 and is formed in a bowl shape capable of receiving waste. The bowl portion 11 includes a waste receiving surface 11a that receives waste, a rim portion 14 formed on the upper edge of the waste receiving surface 11a, and the above-mentioned rim water outlet portion 15.

The rim water spout 15 opens into the inner peripheral surface 14a of the rim portion 14 and is connected to the rim water conduit 16 described above. As a result, the rim water spout 15 spouts the flushing water supplied from the rim water conduit 16 onto the waste receiving surface 11a of the bowl portion 11, generating a swirling flow on the waste receiving surface 11a. Note that below, flushing water being spouted from the rim water spout 15 may be referred to as "rim water spouting."

The drain trap pipe 12 includes an inlet portion 12a, a trap ascending portion 12b, and a trap descending portion 12c. The inlet portion 12a is provided so as to be continuous with the bottom of the waste receiving surface 11a. The inlet portion 12a allows flush water from the bowl portion 11 to flow into the drain trap pipe 12. The trap ascending portion 12b is formed so as to extend obliquely upward from the inlet portion 12a. The trap descending portion 12c is formed so as to extend downward from the trap ascending portion 12b.

A drain pipe 17 is connected to the lower end of the trap descending portion 12c. In the flush toilet 1, when the toilet is flushed, flush water in the bowl portion 11 is drained into the drain pipe 17 via the inlet portion 12a, the trap ascending portion 12b, and the trap descending portion 12c of the drain trap pipe 12.

In addition, in the flush toilet 1, flush water accumulates in the drain trap pipe 12 and bowl portion 11 after the toilet flush has been performed. The flush water that accumulates in the drain trap pipe 12 and other parts is called "reserved water." In this way, when the drain trap pipe 12 and other parts are filled with reserved water, the reserved water functions as a seal, preventing odors and other issues from the drain pipe 17 from flowing back into the bowl portion 11.

Here, we will explain an example of the water level detection means 30 placed in the flush water tank 20. The water level detection means 30 is a water level detection sensor such as a float switch. Hereinafter, the water level detection means 30 will be referred to as a "float switch."

The float switch 30 is positioned at the full water level W0, which is the predetermined water level in the flush water tank 20, and when the water level in the flush water tank 20 is at the full water level W0, it outputs a full water signal to the control unit 60 indicating that the water level is at the full water level W0. Note that the full water level W0 is the initial water level before the toilet is flushed, but the initial water level is not limited to the full water level W0.

The control unit 60 includes a processor (not shown), such as a central processing unit (CPU), and a storage device (not shown), such as a random access memory (RAM). The control unit 60 also controls the pump 50 based on signals input from the float switch 30 and the current value detection means 70.

The control unit 60, for example, controls the pump 50 to flush the toilet. At this time, the control unit 60 starts flushing the toilet when a full water signal is input from the float switch 30.

The pump 50 is, for example, a DC pump having a DC motor (not shown) as a drive source. Therefore, the current value detection means 70 that measures the value of the current (pump current value) flowing through the pump 50 measures, for example, the current value of the winding current of the DC motor. The current value detection means 70 is, for example, configured by a current detection circuit.

The flush toilet 1 also comprises a toilet flushing command receiving means 80 and a limiting means 90. The toilet flushing command receiving means 80 is operated by the user when the user wishes to flush the toilet. The toilet flushing command receiving means 80 is, for example, an operating lever or an operating remote control. The limiting means 90 limits input from the toilet flushing command receiving means during the period from the start of the toilet flush until the establishment of a predetermined condition.

Here, the control unit 60 detects the presence or absence of cleaning water in the cleaning water tank 20 (water presence/absence detection) to avoid driving the pump 50 when there is no cleaning water in the cleaning water tank 20. Furthermore, when performing water presence/absence detection, the control unit 60 determines the presence or absence of cleaning water in the cleaning water tank 20 based on the pump current value.

Figure 3 shows the pump current value when water is present and when water is not present. In Figure 3, the right side of the figure shows the pump current value when water is present, and the left side shows the pump current value when water is not present. In Figure 3, the vertical direction shows the current value (A), and the horizontal direction shows the time (seconds).

As shown in FIG. 3, when water is present, the resistance of the cleaning water when the pump 50 rotates is large, so the current value for rotating the pump 50 is large (high). On the other hand, when water is not present, the resistance of the cleaning water when the pump 50 rotates is small, so the current value for rotating the pump 50 is small (low). In the illustrated example, there is a difference d between the case with water and the case without water.

In water/water-absence detection, the presence or absence of flushing water in the flushing water tank 20 is determined based on whether the pump current value is higher or lower than a predetermined threshold value that has been set in advance. In this case, if the pump current value is higher than the threshold value, it is determined that there is water, and if the pump current value is lower than the threshold value, it is determined that there is no water. In this case, the threshold value is calculated based on the current value when the flushing water tank 20 is full of water, for example.

Here, in the case of the present embodiment, when detecting whether there is water or not by utilizing the difference in current value due to pump characteristics, the current value when the pump 50 is rotated at or above a predetermined number of revolutions if there is cleaning water in the cleaning water tank 20 will always be above the threshold value when the threshold value is initially set, so it is possible to correctly determine that there is cleaning water. However, if the current value changes due to deterioration over time, for example, it may be determined that there is no cleaning water, resulting in a false detection of whether there is water or not.

Figure 4 is an explanatory diagram of false detection of water/water not present. Note that Figure 4 shows patterns of false detection of water/water not present in a table. First, the pattern of false detection of no water will be explained. As shown in Figure 4, in a false detection of no water, if there is actually water in the flush water tank 20 before the toilet flush, it is an erroneous judgment result, and although there is flush water in the flush water tank 20, the pump 50 is stopped. As a result, the toilet cannot be flushed (the toilet cannot be flushed).

In addition, in the case of a false detection of no water, if there is actually no water in the flush water tank 20 before the toilet is flushed, the result is a judgment result that the threshold is abnormal. In this case, since there is no flush water in the flush water tank 20 to begin with, the toilet cannot be flushed (the toilet cannot be flushed). However, even if the judgment result is that there is no water, it is not a normal judgment.

Next, a pattern of false detection of water presence will be described. As shown in FIG. 4, in a false detection of water presence, if there is actually water in the flush water tank 20 before the toilet flushes, the result is a judgment result that the threshold is abnormal. In this case, the toilet can be flushed (the toilet can be flushed), but a normal judgment has not been made.

In addition, a false water presence detection is an erroneous judgment result when there is actually no water in the flush water tank 20 before the toilet is flushed, and although there is no flush water in the flush water tank 20, the pump 50 rotates. However, because the pump 50 is running empty, the toilet cannot be flushed (the toilet cannot be flushed).

In this way, when detecting whether water is present or absent based on the pump current value, the impact is greater when a false detection of no water occurs when water is actually present, and when a false detection of water occurs when water is actually absent, as highlighted by diagonal lines in Figure 4. Of these, when a false detection of water occurs when water is actually absent, the pump 50 will run dry, and this has a greater impact.

For this reason, in this embodiment, the control unit 60 performs a threshold abnormality judgment in response to the above-mentioned threshold abnormality. In the threshold abnormality judgment, the control unit 60 performs a first judgment in which the water level detected by the float switch 30 is compared with a predetermined water level (for example, the full water level) to judge whether water is present or not. In addition, in the threshold abnormality judgment, the control unit 60 performs the first judgment, and then performs a second judgment in which the pump current value is compared with the threshold to judge whether water is present or not. The control unit 60 judges the threshold abnormality based on the judgment results of the first judgment and the second judgment.

Next, an example of a processing procedure for controlling abnormality determination of a threshold value by the control unit 60 will be described with reference to FIG. 5. FIG. 5 is a flowchart showing an example of a processing procedure for controlling abnormality determination of a threshold value.

As shown in FIG. 5, in determining whether the threshold is abnormal, the control unit 60 performs a first determination. That is, the control unit 60 compares the water level detected by the float switch 30 with a predetermined water level to determine whether water is present or not (step S101). If the control unit 60 determines that water is present in the processing of step S101 (step S101: Yes), it stores "water present" in a memory unit (not shown) (step S102), for example, and starts the toilet flushing operation (step S103).

If the control unit 60 determines that there is no water in the process of step S101 (step S101: No), it stores "no water" in the memory unit (step S104). The control unit 60 also starts the toilet flushing operation after the process of step S104 (step S103).

Then, the control unit 60 performs a second determination. That is, the control unit 60 compares the pump current value with a threshold value to determine whether water is present or absent, and determines whether the pump 50 is running dry (step S105). If the control unit 60 determines that the pump 50 is not running dry (step S105: No), it continues the toilet flushing operation (step S106). When the specified time has elapsed, the control unit 60 ends the toilet flushing operation (step S107).

If the control unit 60 determines in the processing of step S105 that the pump 50 is running dry (step S105: Yes), it stops the toilet flushing operation (step S108) and ends the toilet flushing operation (step S107).

Next, the control unit 60 supplies cleaning water to the cleaning water tank 20 via the water supply unit 40 (step S109).

The control unit 60 then determines whether water is present or absent at the start of the toilet flushing operation, for example, using the float switch 30 (step S110). If the control unit 60 determines that water is present in the processing of step S110 (step S110: Yes), it determines whether to stop the toilet flushing operation (step S111). If the control unit 60 determines that the toilet flushing operation should be stopped in the processing of step S111 (step S111: Yes), it counts this as an abnormality determination (step S112).

Next, the control unit 60 determines whether the abnormality determination count is equal to or greater than a specified number (step S113). If the control unit 60 determines that the abnormality determination count is equal to or greater than the specified number (step S113: Yes), it confirms a threshold abnormality (step S115). Note that if the control unit 60 determines in the processing of step S113 that the abnormality determination count is less than the specified number (step S113: No), it ends the abnormality determination processing.

When the control unit 60 determines that a threshold abnormality exists, it resets the threshold (step S116) and ends the abnormality determination process.

The control unit 60 determines that a threshold abnormality exists when the abnormality determination count is equal to or greater than a specified number of times, but may also determine that a threshold abnormality exists when the abnormality determination count is equal to one time, for example.

If the control unit 60 determines in the process of step S110 that there is no water (step S110: No), it resets the abnormality determination count (step S114). If the control unit 60 determines in the process of step S111 that the toilet flushing operation should not be stopped (step S111: No), it also resets the abnormality determination count (step S114). After the process of step S114, the control unit 60 returns to the abnormality determination count process.

According to the flush toilet 1 of the embodiment described above, the float switch 30 detects the water level (actual water level) in the flush water tank 20, and the presence/absence of water is detected by the pump current value, so the number of float switches 30 can be reduced. In addition, since the threshold abnormality determination is performed based on the result of the first determination, i.e., the actual water level detected by the float switch 30, and the result of the second determination, i.e., the presence/absence of water determination result obtained by comparing the pump current value with the threshold value, erroneous detection of the presence/absence of water due to threshold abnormality can be suppressed, and water presence/absence detection can be performed with high accuracy. For these reasons, water presence/absence detection can be performed with high accuracy while reducing the number of float switches 30.

In addition, if an abnormality in the threshold is detected, a new threshold is reset according to the current pump current value, thereby preventing future false detections.

Next, another example of the processing procedure for controlling the threshold abnormality determination by the control unit 60 will be described with reference to Figures 6 and 7. Figures 6 and 7 are flowcharts showing another example of the processing procedure for controlling the threshold abnormality determination.

First, the example shown in FIG. 6 will be described. The example shown in FIG. 6 differs from the example shown in FIG. 5 in that in the process of step S211 described below (the process of step S111 in the example of FIG. 5), it is determined whether or not to stop the toilet flushing operation, and whether or not the water supply time is shorter than a predetermined time.

As shown in FIG. 6, in determining whether the threshold is abnormal, the control unit 60 performs a first determination. That is, the control unit 60 compares the water level detected by the float switch 30 with a predetermined water level to determine whether water is present or not (step S201). If the control unit 60 determines that water is present in the processing of step S201 (step S201: Yes), it stores "water present" in a memory unit (not shown) (step S202), for example, and starts the toilet flushing operation (step S203).

If the control unit 60 determines that there is no water in the process of step S201 (step S201: No), it stores "no water" in the memory unit (step S204). The control unit 60 also starts the toilet flushing operation after the process of step S204 (step S203).

Next, the control unit 60 performs a second determination. That is, the control unit 60 compares the pump current value with a threshold value to determine whether water is present or absent, and determines whether the pump 50 is running dry (step S205). If the control unit 60 determines that the pump 50 is not running dry (step S205: No), it continues the toilet flushing operation (step S206). When the specified time has elapsed, the control unit 60 ends the toilet flushing operation (step S207).

If the control unit 60 determines in the processing of step S205 that the pump 50 is running idle (step S205: Yes), it stops the toilet flushing operation (step S208) and ends the toilet flushing operation (step S207).

Next, the control unit 60 supplies cleaning water to the cleaning water tank 20 via the water supply unit 40 (step S209).

Next, the control unit 60 determines whether water is present or absent at the start of the toilet flushing operation, for example, using the float switch 30 (step S210). If the control unit 60 determines that water is present in the processing of step S210 (step S210: Yes), it determines whether to stop the toilet flushing operation, and determines whether the water supply time is shorter than a predetermined time (step S211). Note that the predetermined time is, for example, the time it takes for the flush water tank 20 to become full when water is supplied to the tank after the toilet flush. If the control unit 60 determines that the toilet flushing operation is stopped in the processing of step S211 and the water supply time is shorter than the predetermined time (step S211: Yes), it counts this as an abnormality determination (step S212).

Next, the control unit 60 determines whether the abnormality determination count is equal to or greater than a specified number (step S213). If the control unit 60 determines that the abnormality determination count is equal to or greater than the specified number (step S213: Yes), it confirms a threshold abnormality (step S215). Note that if the control unit 60 determines in the processing of step S213 that the abnormality determination count is less than the specified number (step S213: No), it ends the abnormality determination processing.

When the control unit 60 determines that a threshold abnormality exists, it resets the threshold (step S216) and ends the abnormality determination process.

The control unit 60 determines that a threshold abnormality exists when the abnormality determination count is equal to or greater than a specified number of times, but may also determine that a threshold abnormality exists when the abnormality determination count is equal to one time, for example.

If the control unit 60 determines in the process of step S210 that there is no water (step S210: No), it resets the abnormality determination count (step S214). If the control unit 60 determines in the process of step S211 that the toilet flushing operation is not stopped and the water supply time is longer than the predetermined time (step S211: No), it also resets the abnormality determination count (step S214). After the process of step S214, the control unit 60 returns to the abnormality determination count process.

According to the flush toilet 1 of the embodiment described above, the float switch 30 detects the water level (actual water level) in the flush water tank 20, and the presence/absence of water is detected by the pump current value, so the number of float switches 30 can be reduced. In addition, since the threshold abnormality determination is performed based on the result of the first determination, i.e., the actual water level detected by the float switch 30, and the result of the second determination, i.e., the presence/absence of water determination result obtained by comparing the pump current value with the threshold value, erroneous detection of the presence/absence of water due to threshold abnormality can be suppressed, and water presence/absence detection can be performed with high accuracy. For these reasons, water presence/absence detection can be performed with high accuracy while reducing the number of float switches 30.

In addition, if the toilet flush is started when there is sufficient flush water in the flush water tank 20 based on the actual water level detected by the float switch 30, and the determination result using the current value detection means is that there is no water, there is a high possibility that the current value detection means has made an erroneous determination. For this reason, if the pump current value is lower than the threshold in the second determination after the first determination, it is determined that there is an abnormality in the threshold, and it is possible to detect that the current threshold is abnormal.

In addition, if the time it takes for the water level in the flush water tank 20 to reach the full water level after the current value detection means has determined that there is no water, is shorter than a predetermined time (the time it takes for the flush water tank 20 to become full after the toilet is flushed), then the current value detection means has not correctly determined whether or not there is flush water in the flush water tank 20, and so it is determined that there is an abnormality in the threshold. This makes it possible to detect that the current threshold is abnormal.

In addition, if an abnormality in the threshold is detected, a new threshold is reset according to the current pump current value, thereby preventing future false detections.

Next, the example shown in FIG. 7 will be described. The example shown in FIG. 7 differs from the example shown in FIG. 6 in that it includes the processing of steps S315 to S317, which will be described later.

As shown in FIG. 7, in determining whether the threshold is abnormal, the control unit 60 performs a first determination. That is, the control unit 60 compares the water level detected by the float switch 30 with a predetermined water level to determine whether water is present or not (step S301). If the control unit 60 determines that water is present in the processing of step S301 (step S301: Yes), it stores "water present" in a memory unit (not shown) (step S302), for example, and starts the toilet flushing operation (step S303).

If the control unit 60 determines that there is no water in the process of step S301 (step S301: No), it stores "no water" in the memory unit (step S304). The control unit 60 also starts the toilet flushing operation after the process of step S304 (step S303).

Then, the control unit 60 performs a second determination. That is, the control unit 60 compares the pump current value with a threshold value to determine whether water is present or absent, and determines whether the pump 50 is running dry (step S305). If the control unit 60 determines that the pump 50 is not running dry (step S305: No), it continues the toilet flushing operation (step S306). When the specified time has elapsed, the control unit 60 ends the toilet flushing operation (step S307).

If the control unit 60 determines in the processing of step S305 that the pump 50 is running idle (step S305: Yes), it stops the toilet flushing operation (step S308) and ends the toilet flushing operation (step S307).

Next, the control unit 60 supplies cleaning water to the cleaning water tank 20 via the water supply unit 40 (step S309).

The control unit 60 then determines whether water is present or absent at the start of the toilet flushing operation, for example, using the float switch 30 (step S310). If the control unit 60 determines that water is present in the processing of step S310 (step S310: Yes), it determines whether to stop the toilet flushing operation, and determines whether the water supply time is shorter than a predetermined time (step S311). Note that the predetermined time is, for example, the time it takes for the flush water tank 20 to become full when water is supplied to the tank after flushing the toilet. If the control unit 60 determines that the toilet flushing operation is stopped in the processing of step S311 and that the water supply time is shorter than the predetermined time (step S311: Yes), it counts this as an abnormality determination (step S312).

If the control unit 60 determines in the process of step S310 that there is no water (step S310: No), it determines whether or not a reception operation has been performed in the toilet flush reception means during the reception prohibition time set by the restriction means (step S315). If the control unit 60 determines in the process of step S315 that a reception operation has been performed (step S315: Yes), it counts this as an abnormality determination (step S312).

The control unit 60 then determines whether the abnormality determination count is equal to or greater than a specified number (step S313). If the control unit 60 determines that the abnormality determination count is equal to or greater than the specified number (step S313: Yes), it confirms a threshold abnormality (step S318). Note that if the control unit 60 determines in the processing of step S313 that the abnormality determination count is less than the specified number (step S313: No), it ends the abnormality determination processing.

When the control unit 60 determines that a threshold abnormality exists, it resets the threshold (step S319) and ends the abnormality determination process.

The control unit 60 determines that a threshold abnormality exists when the abnormality determination count is equal to or greater than a specified number of times, but may also determine that a threshold abnormality exists when the abnormality determination count is equal to one time, for example.

If the control unit 60 determines in the process of step S311 that the toilet flushing operation is not stopped and that the water supply time is longer than the predetermined time (step S311: No), it resets the abnormality determination count (step S314). If the control unit 60 determines in the process of step S315 that no reception operation has been performed (step S315: No), it resets the abnormality determination count (step S317). After the processes of steps S314 and S317, the control unit 60 returns to the abnormality determination count process.

According to the flush toilet 1 of the embodiment described above, the float switch 30 detects the water level (actual water level) in the flush water tank 20, and the presence/absence of water is detected by the pump current value, so the number of float switches 30 can be reduced. In addition, since the threshold abnormality determination is performed based on the result of the first determination, i.e., the actual water level detected by the float switch 30, and the result of the second determination, i.e., the presence/absence of water determination result obtained by comparing the pump current value with the threshold value, erroneous detection of the presence/absence of water due to threshold abnormality can be suppressed, and water presence/absence detection can be performed with high accuracy. For these reasons, water presence/absence detection can be performed with high accuracy while reducing the number of float switches 30.

In addition, if the toilet flush is started when there is sufficient flush water in the flush water tank 20 based on the actual water level detected by the float switch 30, and the determination result using the current value detection means is that there is no water, there is a high possibility that the current value detection means has made an erroneous determination. For this reason, if the pump current value is lower than the threshold in the second determination after the first determination, it is determined that there is an abnormality in the threshold, and it is possible to detect that the current threshold is abnormal.

In addition, if the time it takes for the water level in the flush water tank 20 to reach the full water level after the current value detection means has determined that there is no water, is shorter than a predetermined time (the time it takes for the flush water tank 20 to become full after the toilet is flushed), then the current value detection means has not correctly determined whether or not there is flush water in the flush water tank 20, and so it is determined that there is an abnormality in the threshold. This makes it possible to detect that the current threshold is abnormal.

In addition, after the current value detection means has determined that there is water, if the user's toilet flush operation is detected during the period in which the limiting means 90 is restricting input from the toilet flush reception means 80, it can be presumed that the user will perform the toilet flush operation multiple times because flush water is not flowing, and it can be determined that flush water is not flowing and it can be detected that the current threshold value is abnormal.

In addition, if an abnormality in the threshold is detected, a new threshold is reset according to the current pump current value, thereby preventing future false detections.

In the above embodiment, the flush toilet is a so-called full pump type, in which flush water pressurized by the pump 50 is supplied to the rim water discharge section 15 of the toilet body 10 to flush the toilet, but this is not limited to this. For example, the flush toilet may be a so-called hybrid type, which further includes a jet water discharge section and generates a siphon effect by the water discharged from the jet water discharge section.

In this case, for example, by providing a switching valve downstream of the pump 50 and controlling the switching valve with the control unit 60, it is possible to select whether the cleaning water pressurized by the pump 50 is supplied to the rim water conduit 16 leading to the rim water spout section 15 or to the jet water conduit leading to the jet water spout section.

Further advantages and modifications may readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof.

1 Flush toilet 10 Toilet body 20 Flush water tank 30 Water level detection means (float switch)
50 Pump 60 Control unit 70 Current value detection means 80 Toilet flush reception means 90 Limiting means

Claims (4)

A flush toilet that is flushed with flush water,
The toilet bowl body,
A cleaning water tank for storing cleaning water;
A water supply unit that supplies flush water to the flush water tank;
a pump that supplies flush water stored in the flush water tank to the toilet body;
A control unit for controlling the operation of the pump;
a current value detection means for measuring a current value flowing through the pump;
and a water level detection means for detecting the water level in the flush water tank,
said control unit makes a first determination to determine the presence or absence of flush water in the flush water tank by comparing the water level detected by the water level detection means with a predetermined water level which is a water level at which the water level detection means detects the presence of flush water in the flush water tank, and a second determination to determine the presence or absence of flush water in the flush water tank by comparing the current value measured by the current value detection means with a threshold value, and makes an abnormality determination for the threshold value based on the result of the first determination and the result of the second determination. 2. The flush toilet according to claim 1, wherein, in the first determination, the control unit compares the water level detected by the water level detection means with the predetermined water level to determine that there is flush water in the flush water tank and commences toilet flushing, and, in the second determination, if the current value is lower than the threshold value, determines that there is an abnormality in the threshold value. The flush toilet according to claim 2, wherein, in the second determination, the control unit supplies flush water to the flush water tank by the water supply unit if the current value is lower than the threshold value, and determines that there is an abnormality in the threshold value if the time it takes for the water level detection means to detect the full water level is shorter than a predetermined time. The flush toilet according to any one of claims 1 to 3, wherein when the control unit determines that the threshold value is abnormal, it executes a toilet flush, and resets a new threshold value according to the current value measured by the current value detection means associated with that toilet flush .

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