JP7790895B2 - Dishwasher - Google Patents

Description

The present invention relates to a dishwasher equipped with a washing tub having a bottom wall and multiple side walls rising from multiple sides around the bottom wall, a dish basket that supports dishes stored in the washing tub, a washing nozzle provided in the washing tub, and a washing pump that supplies washing water from the washing tub to the washing nozzle.

Conventionally, dishwashers of this type are known to include a heating means for heating wash water, located in the space between the bottom wall of the washing tub and the dish basket (see, for example, Patent Document 1). In dishwashers equipped with such a heating means, the portion of the bottom wall of the washing tub facing the heating means is heated. If the washing tub is made of a resin material, thermal deterioration of the portion of the bottom wall of the washing tub facing the heating means will reduce the durability of the washing tub.

Here, it is also known that a cleaning tank is divided into an upper frame, a middle frame, and a bottom body, and these are then joined together to assemble the cleaning tank (see, for example, Patent Document 2). It is also conceivable to use this technology to form the bottom body, which is heated by the heating means, from a material with excellent heat resistance, thereby improving the durability of the cleaning tank.

However, with this system, the cleaning tank must be assembled by joining three parts - the upper frame, middle frame, and bottom frame - which makes assembly difficult, and there is also the risk of water leaks occurring due to poor joining of the three parts.

JP 2017-42263 A Japanese Patent Application Laid-Open No. 2005-334360

In light of the above, the present invention aims to provide a dishwasher that eliminates the problems of poor assembly workability and the risk of water leakage, while also ensuring the durability of the washing tub.

To solve the above problems, the present invention provides a dishwasher comprising a washing tub having a bottom wall and multiple side walls rising from multiple sides around the bottom wall, a dish basket for supporting dishes stored in the washing tub, a washing nozzle provided in the washing tub, a washing pump for supplying washing water in the washing tub to the washing nozzle, and a heating means for heating the washing water located in the space between the bottom wall of the washing tub and the dish basket. The washing tub, including the bottom wall and multiple side walls, is integrally molded from a resin material, and the thickness of at least the portion of the bottom wall facing the heating means is thicker than the thickness of each side wall.

According to the present invention, the cleaning tank is molded as a single unit from a resin material, eliminating the problems of poor assembly workability and the risk of water leaks that arise when assembling a cleaning tank by joining three parts. Furthermore, even if thermal degradation occurs in the portion of the bottom wall of the cleaning tank facing the heating means, by increasing the thickness of this portion, the time until this portion deteriorates to its usable limit can be extended, thereby ensuring the durability of the cleaning tank.

1 is a cutaway side view of a dishwasher according to an embodiment of the present invention. 2 is a cross-sectional plan view of a main part of the washing tub of the dishwasher according to the embodiment, taken along line II-II in FIG. 1 . FIG. 3 is an enlarged cross-sectional side view taken along line III-III in FIG. 2. 4 is an enlarged cross-sectional front view taken along line IV-IV in FIG. 2.

The dishwasher according to an embodiment of the present invention shown in Figure 1 is a built-in type that is installed in a system kitchen. It has a washing tub 2 that is stored in a body 1 with an open front and can be freely pulled out forward. The washing tub 2 has a bottom wall 21 and front, rear, and left and right side walls 22, 23, and 24 that rise from the four sides around the bottom wall 21, i.e., the front, rear, and left and right sides. A front lid 25 that closes the front of the body 1 is attached in front of the front side wall 22. A sealing lid 11 that closes the open top of the washing tub 2 is also provided at the top of the body 1.

Water is supplied to the washing tub 2 via a water supply hose from a water supply valve (not shown) located inside the machine body 1. The washing tub 2 also contains a dish basket 3, consisting of a lower basket 31 and an upper basket 32, which support the tableware W, and is equipped with a washing nozzle 4 that sprays washing water toward the dish basket 3. The washing nozzle 4 includes a lower nozzle 41 that extends horizontally below the washing tub 2 and is rotatable about a vertical axis at the longitudinal center, and a center nozzle 42 that extends upward and is erected at the longitudinal center of the lower nozzle 41. A nozzle guard frame 311 is erected at the center of the lower basket 31 to surround the center nozzle 42 and prevent the tableware W placed in it from interfering with the center nozzle 42.

A cleaning pump 5 is installed on the underside of the bottom wall 21 of the cleaning tank 2, and is connected to a cleaning water reservoir 211 recessed in the bottom wall 21. When the cleaning pump 5 is rotated forward, the cleaning water in the cleaning tank 2 is supplied to the cleaning nozzle 4 via the reservoir 211 and the cleaning pump 5, and when the cleaning pump 5 is rotated reversely, the cleaning water is drained from the cleaning tank 2.

A drying fan 6 is attached to the rear surface of the rear sidewall 23 of the washing tub 2. Air blown from the drying fan 6 is supplied into the washing tub 2 through an air supply duct 61 connected to the drying fan 6 and an air inlet 231 located at the bottom of the rear sidewall 23. Furthermore, a heater 7, which serves as a heating device for heating washing water, is located near the air inlet 231 in the space between the bottom wall 21 of the washing tub 2 and the lower basket 31, which serves as the dish basket 3, so that it is submerged below the water surface when water is supplied to the washing tub 2. Specifically, referring to Figure 2, a portion of the bottom wall 21 near the air inlet 231 is recessed downward over a predetermined range, and the heater 7 is positioned within this recess 212. A heat shield 213 is attached to the top surface of the bottom of the recess 212, facing the heater 7.

When the dishwasher's operation switch is turned on, water is first supplied to the washing tub 2. Detergent is mixed into this water from a detergent supply means (not shown) to produce wash water. When the water level in the washing tub 2 reaches a predetermined level, water supply is stopped. The wash water is then heated by the heater 7, and the washing pump 5 is rotated forward to spray the wash water from the washing nozzle 4, performing a washing process for a predetermined time to wash the tableware W held in the dish basket 3. After the washing process is completed, the washing pump 4 is rotated reversely to drain the wash water from the washing tub 2. Next, after water is supplied to the washing tub 2, the washing pump 4 is rotated forward to spray water from the washing nozzle 4, performing a rinsing process for a predetermined time to rinse the tableware W. After the rinsing process is completed, the washing pump 4 is rotated reversely to drain the water from the washing tub 2. Next, the air in the washing tub 2 is heated by the heater 7, and the drying fan 6 is driven to blow air into the washing tub 2, performing a drying process for a predetermined time to dry the tableware W with the blown air.

In this embodiment, the cleaning tank 2, including the bottom wall 21 and the front, rear, left, and right side walls 22-24, are integrally molded from a resin material such as polypropylene. This eliminates the problems of poor assembly workability and the risk of water leakage that arise when assembling a cleaning tank by joining the three components described above: the upper frame, middle frame, and bottom frame.

However, if the cleaning tank 2 is integrally molded from a resin material, even if a heat shield 213 is attached to the upper surface of the portion of the bottom wall 21 of the cleaning tank 2 facing the heater 7, it is not possible to fully prevent thermal deterioration of this portion. Therefore, durability becomes an issue.

In this embodiment, therefore, the thickness of at least the portion of the bottom wall 21 facing the heater 7, specifically the area of the bottom wall 21 indicated by A in Figures 3 and 4, is made thicker than the thickness of each of the side walls 22, 23, and 24 of the cleaning tank 2. For example, the thickness of each of the side walls 22, 23, and 24 is set to 2.5 mm, and the thickness of the area of the bottom wall 21 indicated by A is set to 3.0 mm. In this way, by making the thickness of the portion of the bottom wall 21 facing the heater 7 thicker, even if thermal degradation occurs in this area, the time until this area deteriorates to its usable limit can be extended, thereby ensuring the durability of the cleaning tank 2.

It is also possible to make the thickness of the bottom wall 21 3.0 mm throughout, but in this embodiment, the thickness of the area indicated by B in Figures 3 and 4, which is away from the area indicated by A on the bottom wall 21, is set to 2.5 mm, the same as the thickness of each side wall 22, 23, and 24, and the thickness of the area indicated by C in Figure 3, between the area indicated by A and the area indicated by B, gradually decreases from 3.0 mm to 2.5 mm.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to this. For example, while the above embodiment applies the present invention to a built-in dishwasher, the present invention can also be applied to a countertop dishwasher in which the washing tub does not have a front side wall rising from the front edge of the bottom wall, i.e., the front is open, and a front door is provided to open and close the front of the washing tub.

2...Washing tank, 21...Bottom wall, 22, 23, 24...Side walls, 3...Dish basket, 4...Washing nozzle, 5...Washing pump, 7...Heater (heating means).

Claims (1)

A dishwasher comprising: a washing tub having a bottom wall and a plurality of side walls rising from a plurality of sides around the bottom wall; a dish basket for supporting dishes stored in the washing tub; a washing nozzle provided in the washing tub; a washing pump for supplying washing water in the washing tub to the washing nozzle; and a heating means for heating the washing water, which is arranged in a space between the bottom wall of the washing tub and the dish basket.
The dishwasher is characterized in that the washing tank, including the bottom wall and a plurality of side walls, is integrally molded from a resin material, and the thickness of at least the part of the bottom wall facing the heating means is thicker than the thickness of each side wall.