CROSS REFERENCE TO RELATED APPLICATION

This application claims benefit of priority to Japanese Patent Application No. 2020-144895, filed on Aug. 28, 2020, the entire content of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a flush toilet, and more particularly, to a flush toilet for discharging waste with flush water.

BACKGROUND OF THE INVENTION

Conventionally, as flush toilets for discharging waste with flush water, those that feed, under pressure, flush water that is stored in a storage tank to a toilet main body by a pump to perform toilet flushing are known, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2009-30405) and Patent Document 2 (Japanese Patent Laid-Open No. 2014-114627), for example.

A water supply unit that enables water to be supplied to the storage tank is provided at the storage tank of a conventional flush toilet as described above. The water supply unit is separated from the inside of the storage tank to prevent flush water in the storage tank from flowing backward.

However, with a conventional flush toilet as described above, in the case where a top surface of the storage tank is flat, if the storage tank is installed in a tilted manner due to manufacturing error of the toilet main body or assembly error of the storage tank and the toilet main body, for example, there is a problem that an air lock is formed on a tilted side. Accordingly, there is a problem that the amount of flush water stored in the storage tank is reduced or is varied depending on the volume of the air lock. Furthermore, when the air lock is formed in the storage tank, there is a problem that, when the flush water in the storage tank rises at the time of water supply to the storage tank, the air lock may be captured into the flush water, thereby making abnormal sounds. Accordingly, there is a demand to prevent generation of an air lock in the storage tank even in a state where the storage tank is tilted.

Accordingly, the present invention has been made in view of the problems of the conventional art and the demand as described above, and is aimed at providing a flush toilet that is capable of preventing an air lock that is due to tilting of a storage tank to thereby allow a greater amount of flush water to be stored in the storage tank and to prevent generation of abnormal sounds that are due to the air lock.

SUMMARY OF THE INVENTION

To solve the problems as described above, the present invention is a flush toilet for discharging waste with flush water, the flush toilet comprising: a toilet main body including a bowl configured to receive waste, and a discharge trap configured to discharge the waste in the bowl; and a tank device configured to supply flush water to the toilet main body, wherein the tank device includes a storage tank provided behind the toilet main body and above a floor surface, the storage tank being configured to store the flush water to be supplied to the toilet main body, the tank device further includes a water supply unit configured to supply the flush water to the storage tank, the storage tank includes a first upper surface, a second upper surface, and a third upper surface, the first upper surface including a water passage port through which the flush water supplied from the water supply unit flows into the storage tank, the second upper surface being lower than the first upper surface, and the third upper surface being provided between the first upper surface and the second upper surface and being lower than the second upper surface, and the storage tank further includes an air vent unit provided at the second upper surface, the air vent unit being configured to purge air from the storage tank. According to the present invention configured in the above manner, first, even if an air lock is formed inside the storage tank at the time of supply of water from the water supply unit to the storage tank, the water passage port provided in the first upper surface of the storage tank may function as an air vent port that facilitates escape of air of the air lock. Furthermore, flush water that is supplied from the water supply unit flows into the storage tank after passing through the water passage port in the first upper surface of the storage tank, and a water level in the storage tank is thereby raised. The entire upper surface of the storage tank is formed unevenly due to the first upper surface where the water passage port is provided, the second upper surface that is lower than the first upper surface, and the third upper surface that is lower than the second upper surface and that is provided between the first upper surface and the second upper surface. Accordingly, for example, when the water level, in the storage tank, that is lower than the third upper surface rises and reaches the third upper surface, and then, further rises to a height position between a height position of the third upper surface and a height position of the second upper surface, a state is reached where the air lock is easily formed between the water surface and the second upper surface. However, because the air vent unit is provided at the second upper surface of the storage tank, air in the storage tank can be purged by the air vent unit. Accordingly, the air lock between the water surface inside the storage tank and the second upper surface may be released to outside through the air vent unit. Accordingly, when the water level, in the storage tank, that is lower than the third upper surface rises and reaches the third upper surface and further rises to a height position between the height position of the third upper surface and the height position of the second upper surface, air of the air lock in the storage tank may be allowed by the air vent unit to easily escape. Therefore, thanks to the air vent unit as described above, generation of the air lock in the storage tank may be effectively prevented. Furthermore, generation of abnormal sounds due to the air lock inside the storage tank (such as abnormal sounds that are generated when the air lock inside the storage tank is captured during water supply, abnormal sounds that are generated at the time of deaeration of the air of the air lock from the water passage port (degassing sounds), and the like) may also be effectively prevented. Furthermore, the amount of flush water that is supplied from the water supply unit and stored in the storage tank may be prevented from being reduced or varied due to the air lock in the storage tank. Accordingly, a greater amount of flush water can be stored in the storage tank.

Next, the present invention is a flush toilet for discharging waste with flush water, the flush toilet comprising: a toilet main body including a bowl configured to receive waste, and a discharge trap configured to discharge the waste in the bowl; and a tank device configured to supply flush water to the toilet main body, wherein the tank device includes a storage tank provided behind the toilet main body and above a floor surface, the storage tank being configured to store the flush water to be supplied to the toilet main body, the tank device further includes a water supply unit configured to supply the flush water to the storage tank, the storage tank includes a first upper surface and a second upper surface, the first upper surface including a water passage port through which the flush water supplied from the water supply unit flows into the storage tank, and the second upper surface being lower than the first upper surface, and the storage tank further includes an air vent unit provided at the second upper surface, the air vent unit being configured to purge air from the storage tank. According to the present invention configured in the above manner, first, even if an air lock is formed inside the storage tank at the time of supply of water from the water supply unit to the storage tank, the water passage port provided in the first upper surface of the storage tank may function as an air vent port that facilitates escape of air of the air lock. Furthermore, flush water that is supplied from the water supply unit flows into the storage tank after passing through the water passage port in the first upper surface of the storage tank, and a water level in the storage tank is thereby raised. The entire upper surface of the storage tank is formed unevenly due to the first upper surface where the water passage port is provided, and the second upper surface that is lower than the first upper surface. Accordingly, in a state where the water level inside the storage tank is lower than the second upper surface, a state is temporarily reached where the air lock is easily formed between the water surface and the second upper surface. However, because the air vent unit is provided at the second upper surface of the storage tank, air in the storage tank can be purged by the air vent unit. Accordingly, the air lock between the water surface inside the storage tank and the second upper surface may be released to outside through the air vent unit. Accordingly, when the water level, in the storage tank, that is lower than the second upper surface rises to close to the second upper surface, air of the air lock in the storage tank may be allowed by the air vent unit to easily escape. Therefore, thanks to the air vent unit as described above, generation of the air lock in the storage tank may be effectively prevented. Furthermore, generation of abnormal sounds due to the air lock inside the storage tank (such as abnormal sounds that are generated when the air lock inside the storage tank is captured during water supply, abnormal sounds that are generated at the time of deaeration of the air of the air lock from the water passage port (degassing sounds), and the like) may also be effectively prevented. Furthermore, the amount of flush water that is supplied from the water supply unit and stored in the storage tank may be prevented from being reduced or varied due to the air lock in the storage tank. Accordingly, a greater amount of flush water can be stored in the storage tank.

In the present invention, preferably, the storage tank has an asymmetrical shape in a left-right direction so as to include a large tank section and a small tank section, the large tank section being disposed on a large-capacity side of the storage tank when the storage tank is divided into two at a center in the left-right direction, and the small tank section being disposed on a small-capacity side of the storage tank when the storage tank is divided into two at the center in the left-right direction, and the first upper surface is located on an upper surface of the large tank section, and the second upper surface is located on an upper surface of the small tank section. According to the present invention configured in the above manner, because the storage tank has a shape that is asymmetrical in the left-right direction due to the large tank section and the small tank section, the amount of stored water in the large tank section and the amount of stored water in the small tank section are different in the left-right direction. Accordingly, the storage tank is in a state where the entire storage tank is easily tilted with outside of the large tank section with a large amount of stored water (large weight) lowered relative to the center of gravity of the storage tank and outside of the small tank section with a small amount of stored water (small weight) raised relative to the center of gravity of the storage tank. With such tilting of the entire storage tank, escape of air of the air lock especially at an upper part in the small tank section of the storage tank from the air vent unit at the upper surface (the second upper surface) of the small tank section may be facilitated. Accordingly, the air lock between the water surface in the small tank section of the storage tank and the second upper surface may be released to outside through the air vent unit. Accordingly, generation of the air lock inside the storage tank (especially inside the small tank section) may be effectively prevented by the air vent unit. Furthermore, generation of abnormal sounds due to the air lock inside the storage tank (such as abnormal sounds that are generated when the air lock inside the storage tank is captured during water supply, abnormal sounds that are generated at the time of deaeration of the air of the air lock from the water passage port (degassing sounds), and the like) may also be effectively prevented. Accordingly, generation of abnormal sounds due to the air lock inside the storage tank (such as abnormal sounds that are generated when the air lock inside the small tank section of the storage tank is captured during water supply to the storage tank, abnormal sounds that are generated at the time of deaeration of the air of the air lock inside the small tank section of the storage tank from the water passage port in the upper surface (the first upper surface) of the large tank section (degassing sounds), and the like) may also be effectively prevented. Furthermore, the amount of flush water that is supplied from the water supply unit and stored in the large tank section and the small tank section of the storage tank may be prevented from being reduced or varied due to the air lock in the storage tank (especially in the small tank section). Accordingly, a greater amount of flush water may be stored in the large tank section and the small tank section of the storage tank. Moreover, because the entire storage tank is allowed to have a shape that is asymmetrical in the left-right direction due to the large tank section and the small tank section of the storage tank, freedom may be increased in relation to design and layout of peripheral units to be arranged in the periphery of the storage tank of the tank device.

With the flush toilet of the present invention, an air lock that is due to tilting of the storage tank may be prevented, and thus, a greater amount of flush water may be stored in the storage tank, and also, generation of abnormal sounds that are due to the air lock may be prevented.

