JP4709692B2 - Dishwasher - Google Patents

Description

  The present invention relates to a dishwashing machine provided with a cleaning tank and a cleaning means for injecting cleaning water toward the dishes contained in the cleaning tank in the outer box, in particular, heated steam in the cleaning tank. The present invention relates to a dishwasher having a function of supplying food.

Household dishwashers use a washing pump to pump up washing water stored in a washing tank and spray it from an injection nozzle to wash off dishes. In addition, before the cleaning process is executed, a steam process of supplying heated steam into the cleaning tank is executed as a pre-washing process, which swells dirt stuck to tableware and improves the cleaning efficiency in the cleaning process. A dishwasher is provided. In order to perform such a steam process, conventionally, as seen in Patent Document 1, for example, a steam provided with a water storage chamber and a heater for heating water in the water storage chamber on the side surface of the cleaning tank in the outer box Arrangement of the generator is carried out.
JP-A-2-82930

  In recent dishwashers, it is required to increase the volumetric efficiency (ratio of the volume of the washing tank to the volume (outside dimension) of the outer box). For this reason, in the structure which arrange | positions a steam generator in the side surface of the washing tank in an outer case like the past, volume efficiency deteriorates and the problem that a washing tank becomes narrow compared with an external dimension comes out.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to realize a structure capable of performing a steam process for supplying heated steam into a cleaning tank without deteriorating volumetric efficiency. An object of the present invention is to provide a dishwasher that can achieve reduction in manufacturing cost and that can provide an effect such that supply of heated steam can be continued in a stable state.

The invention described in claim 1 is a dishwasher provided with cleaning means for spraying cleaning water toward the cleaning tank and the dishes accommodated in the cleaning tank in the outer box,
A steam generation unit that is formed in a closed container shape having a water supply port and a steam discharge port, and is disposed in a space between the bottom of the cleaning tank and the bottom of the outer box, and heats the steam generation unit in the space A heat source that can be disposed, a jet port formed in the cleaning tank so as to open in the tank, a water supply unit that supplies water into the steam generation unit through the water supply port in an operating state, and the water supply unit And detecting means for detecting the state in which all of the water supplied into the steam generating unit has evaporated, and a control means for operating the water supply means for a predetermined time each time the detecting means enters a detection state. ,
The steam generated in the steam generation unit is configured to be supplied from the steam discharge port into the cleaning tank through the jet port, and the operation time of the water supply unit controlled by the control unit is The configuration is such that the shorter the time from when the water is supplied into the steam generating unit until the detection means enters the detection state, the longer the time is.

  In a dishwasher provided with cleaning means for spraying cleaning water toward the cleaning tank and the dishes stored in the cleaning tank in the outer box, between the bottom of the cleaning tank and the bottom of the outer box There is a circumstance that there is a space (gap) that becomes a dead space. In the means according to claim 1, the steam generating unit formed in the shape of a sealed container having a water supply port and a steam discharge port, and a heat source capable of heating the steam generating unit are arranged in the space portion serving as the dead space. Therefore, there is no possibility that the presence of the steam generation unit and the heat source will cause a deterioration in volumetric efficiency related to the cleaning tank. In addition, the steam generated by heating the water supplied through the water supply means in such a steam generation unit is configured to be supplied into the cleaning tank through a spout formed so as to open in the cleaning tank. Therefore, as a result, a structure capable of performing a steam process for supplying heated steam into the cleaning tank can be realized without deteriorating volumetric efficiency.

  In this case, the control means, every time when the detection means is in the detection state, that is, every time when the water supplied into the steam generation unit by the water supply means at the time of execution of the steam process as described above, is in a state where all the water is evaporated. It has the structure which performs the water supply operation | movement which operates a water supply means only for predetermined time. In such a configuration, variation in the output of the heat source (in the case of an electric heater, variation due to fluctuations in the power supply voltage, etc.), or variation in the amount of water supplied per unit time by the water supply means (water supply performance) In particular, when the output of the heat source is relatively high, or when the amount of water supply per unit time is relatively low, the steam is supplied into the steam generation unit. Since water evaporates in a short time, a phenomenon occurs in which the temperature of the steam generation unit becomes higher than normal and the number of operations of the water supply means increases.

  Assuming that such a phenomenon occurs, it is necessary to select an expensive material having high heat resistance for the components and support structure of the steam generation unit, and an expensive one having excellent durability as a water supply means As a result, there is a problem in that the manufacturing cost increases. On the other hand, when the amount of water supply per unit time is relatively large, there is a problem that the degree of temporary temperature drop of the steam generation unit becomes large and the generation of heated steam becomes unstable. In addition, a part of the water supplied into the steam generation unit may be discharged from the steam discharge port of the steam generation unit into the cleaning tank without becoming water vapor. There is a danger of giving suspicious feelings.

  On the other hand, according to the means described in claim 1, the control means determines the operation time of the water supply means until the detection means is in a detection state after supplying water into the steam generation unit (supplied into the steam generation unit). Because the control is changed so that the longer the time (until all the water is evaporated) is, the longer it is, the variation in the output of the heat source and the amount of water supply per unit time by the water supply means Even if there is a variation of the above, there is no possibility that the time until the water supplied into the steam generating unit evaporates is inadvertently shortened. As a result, it is possible to prevent the occurrence of a phenomenon in which the temperature of the steam generating unit becomes higher than normal or a phenomenon in which the number of operations of the water supply means increases. This eliminates the need to select expensive materials with high heat resistance for the components and support structure of the steam generation unit, and eliminates the need to select expensive and highly durable water supply means. Cost reduction can be realized. In addition, it is possible to prevent a situation where the amount of water supply per unit time is relatively large, that is, a situation in which the degree of temporary temperature decrease of the steam generation unit becomes large, so that the generation of heated steam may become unstable. The supply of heated water vapor can be continued in a stable state. In addition, since a situation in which the amount of water supply per unit time is relatively increased can be prevented in advance, a part of the water supplied into the steam generation unit does not become steam, but the steam of the steam generation unit. The possibility of being discharged from the discharge port into the cleaning tank is reduced, and the generation of abnormal noise as described above can be prevented.

(First embodiment)
A first embodiment (corresponding to claims 1 and 2) in which the present invention is applied to a household dishwasher will be described below with reference to FIGS.

  FIG. 7 shows the external appearance of the dishwasher 11. In FIG. 7, the dishwasher 11 includes an outer box 13 in which a washing tank (indicated by reference numeral 12 in FIGS. 5 and 6) is installed, and the washing tank 12 is provided in front of the outer box 13. A lower door 14 and an upper door 15 provided to open and close the front opening, and an operation panel 16 provided below the lower door 14 are provided. The operation panel 16 is provided with various switches and a display unit.

  The lower door 14 is pivotally supported by the outer box 13 at the lower end portion thereof, and the upper door 15 is pivotally supported by the outer case 13 at the upper end portion thereof. It is configured to rotate. The lower door 14 and the upper door 15 are configured so that the closed state is held by a lock mechanism (not shown), and a push button 17 for unlocking the lock mechanism is provided on the front surface of the lower door 14. Is provided. With these configurations, the doors 14 and 15 are opened by pressing the push button 17 and pulling the lower door 14 forward. The upper door 15 is provided with an exhaust port 18 for discharging water vapor in the cleaning tank 12.

  FIG. 5 shows a vertical cross-sectional structure of the dishwasher 11, and FIG. 6 shows the appearance of the dishwasher 11 with the lower door 14 and the upper door 15 opened. 5 and 6, the upper and lower tableware baskets 19 a and 19 b are accommodated in the washing tank 12 so as to be able to be taken in and out. Note that at least the bottom wall portion of the cleaning tank 12 is formed of a synthetic resin.

  An injection nozzle 20 (corresponding to a cleaning means) for injecting cleaning water toward the tableware stored in the tableware baskets 19a and 19b is fixed to the back wall in the cleaning tank 12. The injection nozzle 20 has a configuration in which a plurality of injection holes 20b are formed on the front surface of a band-shaped hollow member 20a extending left and right along the inner wall of the cleaning tank 12. A cylindrical portion 21 extending to the lower portion of the cleaning tank 12 is integrally communicated with a middle portion of the hollow member 20a. In addition, two rotary spray nozzles 22 (corresponding to cleaning means) for spraying cleaning water toward the tableware stored in the tableware baskets 19a and 19b are provided on the left and right sides of the cleaning tank 12. It is provided side by side. These injection nozzles 22 have a structure that self-rotates in response to the washing water injection, and has a structure in which a plurality of injection holes 22b are formed on the upper surface of a hollow arm portion 22a, and the base end of the arm portion 22a. The part is rotatably connected to the arm support 23.

  A water reservoir 24 is formed in a recessed manner at the front (front side) of the bottom of the cleaning tank 12. The right part of the water storage part is formed in a shallow bottom, and a sheathed heater 25 for cleaning water heating and drying operation is disposed in the shallow bottom part. In addition, a removable residual filter 26 is disposed at the bottom (deep bottom) on the left side of the water reservoir 24, and a protective cover 27 made of a perforated plate is placed over the sheathed heater 25.

  In the space between the bottom of the cleaning tank 12 and the bottom of the outer box 13, a pump 28 that also serves as a cleaning pump and a drainage pump and a blower 29 are disposed. Although detailed description is omitted, the pump 28 includes a casing 30 that houses a cleaning impeller and a drain impeller (both not shown), and a pump motor (not shown) that rotationally drives the cleaning impeller and the drain impeller. And. When the pump motor rotates in the forward direction, for example, the pump 28 functions as a cleaning impeller and the drain impeller does not function. On the other hand, when the pump motor rotates in the reverse direction, the drain impeller functions and the cleaning impeller does not function. That is, the pump 28 is configured to be switchable between a state that functions as a cleaning pump and a state that functions as a drainage pump by switching the rotation direction of the pump motor.

  A cleaning discharge port (not shown) is provided in the upper portion of the casing 30, and the discharge port is connected to each lower portion of the arm support 23 and the cylindrical portion 21 through water distribution pipes 31 a and 31 b. ing. A drain outlet (not shown) is provided on the side of the casing 30, and a drain hose 32 is connected to the outlet. The drainage hose 32 is drawn out from the lower part of the rear side portion of the outer box 13 through a position higher than the highest water level in the cleaning tank 12.

  A cylindrical portion 33 is integrally communicated with the bottom portion of the casing 30, and this cylindrical portion 33 is connected to a lower end portion (residual filter 26 is disposed) of the water storage portion 24 via a connecting pipe 34 extending in the lateral direction. Communicated to the deep bottom). Although not shown, a cleaning suction port and a discharge suction port are formed at a position corresponding to the inside of the cylindrical portion 33 in the lower portion of the casing 30. On the other hand, the inside of the connecting pipe 34 is divided into a cleaning water channel and a drainage channel, the end of the cleaning water channel communicates with the cleaning suction port, and the end of the drainage channel communicates with the drainage suction port. Yes.

  In this case, when the pump 28 functions as a drainage pump, the wash water in the water storage section 24 passes through the drainage passage in the connection pipe 34 and is sucked into the casing 30 from the drainage suction port, and then the casing 30. Is discharged to the outside through a drainage hose 32 from a discharge outlet for drainage provided on the side of the drainage. On the other hand, when the pump 28 functions as a cleaning pump, the cleaning water in the water storage section 24 passes through the cleaning water channel in the connection pipe 34 and is sucked into the casing 30 from the cleaning suction port. The cleaning water sucked in this way is discharged from the cleaning discharge port provided in the upper part of the casing 30 to the water distribution pipes 31 a and 31 b and is injected into the cleaning tank 12 from the injection nozzles 20 and 22.

  The blower 29 is disposed in the vicinity of the sheathed heater 25 in the space between the bottom of the cleaning tank 12 and the bottom of the outer box 13. The blower 29 is composed of a fan and a fan motor (both not shown) housed in a casing 35, and the casing 35 is located near the sheathed heater 25 in the cleaning tank 12 via a blower pipe 36. It is communicated.

  A water supply port body 37 is provided at the center of the rear part of the bottom of the cleaning tank 12. The water supply port 37 is formed in a state in which the bottom portion of the cleaning tank 12 is vertically penetrated in an integrally formed manner, and the upper portion of the tubular portion 37a has a predetermined gap therebetween. It is comprised from the cover 37b to cover. Further, a water supply pipe 39 is connected to the lower part of the cylindrical portion 37a through a water supply valve 38. The water supply pipe 39 passes through the lower part of the rear portion of the outer box 13 and is drawn to the outside of the outer box 13, and the leading end of the water supply pipe 39 is a water supply source such as a water supply via a water supply hose (not shown). To be connected to.

  Now, a steam generation unit 40 related to the gist of the present invention is arranged in the space between the bottom of the cleaning tank 12 and the bottom of the outer box 13, and hereinafter, the steam generation unit 40 and related parts are arranged. The configuration will be described. The steam generation unit 40 is attached and fixed to the bottom of the cleaning tank 12, but in FIG. 5 where the arrangement state is shown, the steam generation unit 40 is shown in order to avoid complication of the drawing. The illustration of 40 mounting structures is omitted. However, the mounting and fixing structure will be described later with reference to another drawing (FIG. 13).

  That is, FIGS. 9, 10 and 11 show a perspective view and a longitudinal sectional view of the steam generation unit 40, respectively, and FIG. 12 shows a bottom view and a perspective view of the main body 41 of the steam generation unit 40, respectively. It is shown.

  9 to 12, the steam generation unit 40 is screwed with a rectangular lid portion 42 for closing the upper surface opening portion of the main body portion 41 formed in a flat rectangular (rectangular) container shape. It has a fixed structure. In this case, in the steam generation unit 40, a rectangular frame-shaped heat-resistant packing 43 is interposed on the entire circumference of the abutting portion between the main body portion 41 and the lid portion 42, so that the steam generation unit 40 can be compared with the width and depth dimensions. Thus, it is formed in a closed container shape having a relatively low height dimension. In addition, the main-body part 41 and the cover part 42 are formed by die-casting of aluminum which is a metal with good thermal conductivity, for example.

  The concave portion in the main body 41 functions as a heating tray 41a for generating heated steam, and the water supply port 44 and the steam discharge port 45 are in the lid 42 at a position facing the heating tray 41a from above. The portions 42 are formed in a state of being separated from each other in the longitudinal direction. The water supply port 44 and the steam discharge port 45 are each provided with a cylindrical body 44a and 45a integrally formed so as to protrude upward from the upper surface of the lid portion 42. In this case, the cylindrical body 44a The inner diameter (the diameter of the water supply port 44) is relatively small, whereas the cylindrical body 45a has a relatively large inner diameter (the diameter of the steam discharge port 45).

  In addition, at a position corresponding to the water supply port 44 on the lower surface of the lid portion 42, a partition wall portion 44b having a semicircular cross-section having a shape surrounding the water supply port 44 from the direction of the heating dish 41a is integrated so as to protrude downward. Is formed. Further, for example, four boss portions 46 used for mounting and fixing the steam generation unit 40 are integrally formed on the upper surface of the lid portion 42.

  In the main body 41, the bottom of the heating pan 41a (corresponding to the inner bottom of the steam generating unit 40) is formed in a shape that is inclined downward from the water supply port 44 side toward the steam discharge port 45 side. Moreover, the step part 41b of the form which stood up from the other site | part is formed in the site | part which opposes the water supply port 44 from the bottom at the bottom part of the heating plate 41a, and the upper surface of this step part 41b is a center part of the heating plate 41a. The structure is inclined downward as it goes in the direction.

  A U-shaped sheathed heater 47 (corresponding to a heat source) is attached to and integrated with the bottom wall portion of the main body portion 41. The sheathed heater 47 is arranged along the periphery of the main body 41, and the power terminals 47a and 47a at both ends are connected to the outside from the side surface of the main body 41 (the surface on the stepped portion 41b side). It is protruding. The steam discharge port 45 is provided at a position substantially corresponding to the center of the arc-shaped bent portion of the sheathed heater 47, that is, a position corresponding to a portion where the heating energy by the sheathed heater 47 is most concentrated in the steam generating unit 40. It will be.

  A radiating fin 48 extending in the longitudinal direction is integrally provided at the center of the bottom of the heating dish 41a in the main body 41. In addition, a hole (not shown) reaching the inside of the heat radiating fin 48 is formed in the central portion of the outer bottom surface of the main body 41, and in one hole, the bottom temperature of the steam generating unit 40, that is, A thermistor 49 (corresponding to detection means) for detecting the temperature of the heating pan 41a is accommodated. Further, a tapping screw 51 for fixing a presser plate 50 for preventing the thermistor 49 from falling off is screwed into the other hole. Note that a plurality of heat radiation fins 52 arranged in a direction orthogonal to the heat radiation fins 48 are integrally formed on both sides of the heating pan 41 a in the main body 41.

  A pair of flange portions 53 and 54 are integrally formed on both sides of the main body portion 41 at a position corresponding to the vapor discharge port 45, and a thermal fuse 53 a and a flange portion 53 and 54 are respectively formed on the lower surfaces of the flange portions 53 and 54. 54a (shown only in FIG. 9) is attached in a heat transfer manner. The temperature fuses 53a and 54a are inserted in series in the power supply path to the sheathed heater 47.

  In the steam generation unit 40 configured as described above, when water is supplied from the water supply port 44 while the sheathed heater 47 is energized, the water flows into the heating dish 41a and is heated. Steam is generated, and the heated steam is discharged from the steam discharge port 45.

  As shown in FIG. 5, the steam generation unit 40 is in a horizontal state in the space between the bottom of the cleaning tank 12 and the bottom of the outer box 13 (the bottom of the heating dish 41a is from the water supply port 44 side to the steam discharge port 45 side. The power supply terminals 47a and 47a of the sheathed heater 47 are arranged on the control circuit unit 55 arranged at a position near the front in the space (the back side of the operation panel 16). On the other hand, the thermal fuses 53a and 54a are connected in series (connection lead wires are not shown).

  In this case, the water supply port 44 (particularly the cylindrical body 44a) of the steam generation unit 40 is connected to a water supply valve (reference numeral 67 in FIG. 3) via a tube 56 having flexibility and heat resistance of about 200 ° C. Indicated: equivalent to water supply means). Further, as shown in an enlarged view in FIG. 8, the cleaning tank 12 is provided with a spout 57 formed by a cylindrical member 57 a having a shape that vertically penetrates the bottom of the cleaning tank 12. The steam discharge port 45 (particularly, the cylindrical body 45a) of the steam generation unit 40 is flexible and has a temperature of about 200 ° C. with respect to the lower end portion (the portion protruding downward from the bottom portion of the cleaning tank 12) of the cylindrical member 57a. It is connected through a tube 58 having heat resistance.

  In this case, the protruding portion of the cylindrical member 57a into the cleaning tank 12 covers the upper end opening (that is, the jet outlet 57) of the cylindrical member 57a from above and is positioned below the upper end opening. A cover member 59 in which an opening 59a serving as a water vapor passage is formed is provided. The cover member 59 is fixed to the boss portion 12a erected integrally with the bottom portion of the cleaning tank 12 by screwing. At the time of screwing, the cylindrical member 57a is fastened together. It has a configuration. The cylindrical member 57 a includes a flange portion 57 b for preventing the separation, and an O-ring 57 c for sealing is interposed between the flange portion 57 b and the bottom portion of the cleaning tank 12.

  FIG. 13 is an exploded perspective view showing a structure for mounting and fixing an integrated body of the steam generating unit 40 and the sheathed heater 47, which will be described below. In FIG. 13, illustration of the thermal fuses 53a and 53b (see FIG. 9) attached to the steam generation unit 40 is omitted.

  That is, in FIG. 13, for example, a first support plate 60 (corresponding to a support member) formed by processing an iron plate has a rectangular frame portion 60a corresponding to the upper surface shape of the steam generation unit 40, and the rectangular frame portion 60a. The three arm portions 60b projecting outward from the three locations are integrally formed. The first support plate 60 is fixed to the upper surface of the steam generation unit 40 by screwing the rectangular frame portion 60 a to the four boss portions 46 included in the lid portion 42 of the steam generation unit 40.

  For example, a second support plate 61 (corresponding to a support member) formed of a heat-resistant synthetic resin such as PBT (polybutylene terephthalate) is formed on a plurality of boss portions 12b integrally formed to protrude outside the bottom surface of the cleaning tank 12. On the other hand, it is fixed by screwing.

  The first support plate 60 is fixed by screwing to a plurality of boss portions (not shown) integrally projecting outside the bottom surface of the second support plate 61. In this case, since the heat from the steam generation unit 40 is transmitted to the second support plate 61 via the arm portion 60b of the first support plate 60, the heat conduction is present in the presence of the arm portion 60b and the second support plate. It is suppressed by the heat insulating function obtained by the plate 61. Further, when the first support plate 60 is fixed, the first heat shield plate 62 for shielding the radiant heat from the steam generating unit 40 is fastened together. The first heat shield plate 62 is connected to the steam generating unit 40. It is set as the shape which covers from the upper surface, a side surface, and a back surface. In addition, a second heat shield plate 63 configured to cover the steam generating unit 40 from the lower side is also prepared, and the second heat shield plate 63 is a plurality of protrusions integrally formed outside the bottom surface of the cleaning tank 12. The boss portions 12c are fixed by screwing.

  FIG. 3 schematically shows the electrical configuration of the dishwasher 11 by combining functional blocks. In FIG. 3, the operation of the dishwasher 11 is controlled by a control microcomputer 64 (corresponding to a control means) provided in the control circuit unit 55. The control microcomputer 64 includes switch signals from various switches 16 a provided on the operation panel 16, a water level detection signal from a water level switch 65 provided to detect the water level in the washing tank 12, and the washing tank 12. The temperature detection signal from the thermistor 66 provided to detect the internal temperature and the temperature detection signal from the thermistor 49 provided to detect the bottom temperature of the steam generation unit 40 are input. ing.

  The control microcomputer 64 includes a display unit 16b provided in the operation panel 16, a sheathed heater 25 for heating and drying operation of the cleaning water, a pump 28, and a blower based on the above input signals and a preset program. 29, the operation control of the water supply valve 38 for washing water, the sheathed heater 47 for steam generation, and the water supply valve 67 is executed.

The flowchart of FIG. 1 shows a part related to the gist of the present invention among the contents of control by the control microcomputer 64, and this will be described below together with related actions.
That is, FIG. 1 shows a steam process control routine performed prior to the cleaning process. In this control routine, the initial flag is first set to “1” (step S1), and then the sheathed heater 47 is set. Is energized (step S2).

  Thereafter, it is determined whether or not the elapsed time after the start of the steam process control routine has become, for example, 5 minutes or more, which is a time corresponding to the set duration of the steam process (step S3). In a state where 5 minutes or more have not elapsed, it is determined whether or not the temperature detected by the thermistor 49 (that is, the bottom temperature of the steam generation unit 40) has reached or exceeded a preset reference temperature (eg, 110 ° C.) (step S4). ).

  If the relationship of detected temperature <reference temperature is established, the process returns to step S3. However, if the relationship of detected temperature ≧ reference temperature is established, it is determined whether or not the initial flag is “1” (step S5). When the initial flag is “1” (that is, when the relationship of detected temperature ≧ reference temperature is established for the first time after the start of the steam process control routine), the water supply connected to the water supply port 44 of the steam generation unit 40 After step S6 for driving the valve 67 for a preset initial water supply time (for example, 1.5 seconds) and step S7 for resetting the initial flag to “0” are sequentially executed, the process returns to step S3. Note that after the first water supply operation is performed, the state in which all of the water supplied into the steam generating unit has evaporated is detected by determining “YES” in step S4.

  By driving the water supply valve 67 as described above, water is supplied into the steam generation unit 40 in a state heated to a reference temperature or higher, and the water flowing into the heating dish 41a is heated accordingly. Steam is generated, and the heated steam is supplied into the cleaning tank 12 from the steam discharge port 45 through the tube 58 and the jet outlet 57.

  When it is determined in step S5 that the initial flag is “0” (that is, when the first water supply into the steam generation unit 40 has been completed), the previous water supply operation execution time (for example, the water supply operation) Is set as a water supply interval TA (step S8), and thereafter, step S9 for determining the water supply time T by the following method is set. Execute.

  Specifically, the control microcomputer 64 stores a water supply time determination table as shown in FIG. This water supply time determination table is for determining the water supply time T using the previous water supply time (continuation time during the water supply operation) and the water supply interval TA determined in step S8 as parameters. Then, the water supply time T is determined using the water supply time determination table. In this case, in the water supply time determination table, the water supply time T is basically set to be longer as the water supply interval TA is shorter, and the water supply time T is shorter than the previous water supply time. The setting is shortened as time passes.

  After determining the water supply time T as described above, the water supply valve 67 is driven for the time T (step S10), and after that, for example, step S11 is waited until 10 seconds have elapsed, and then the process returns to step S3. .

  That is, when it is detected that all of the water supplied to the steam generation unit 40 has evaporated, water is newly supplied into the heating dish 41a, thereby heating the steam into the cleaning tank 12. Supply will continue. Steps S3 and S4 are executed after a waiting time of 10 seconds has elapsed after the water supply valve is driven, that is, after the temperature detected by the thermistor 49 has been reliably lowered to 110 ° C. or less in accordance with the water supply to the heating pan 41a. Therefore, it is possible to prevent a situation where the water supply operation in step S10 is performed unnecessarily.

On the other hand, when 5 minutes or more have elapsed after the start of energization of the sheathed heater 47 (step S3: YES), the steam process control routine is terminated after executing step S12 of disconnecting the sheathed heater 47. In step S12, when the sheath heater 47 is disconnected, for example, when the temperature detected by the thermistor 49 rises to a temperature slightly lower than the reference temperature (when the water supplied to the steam generation unit 40 is all evaporated due to residual heat). (Expected timing)
In short, as shown in the timing chart of FIG. 4, in the control routine, the sheathed heater 47 is continuously energized for 5 minutes after the start, and in the energizing period, the inside of the heating pan 41 a of the steam generating unit 40. A water supply valve 67 for supplying water is intermittently driven every time T to perform a water supply operation, and according to this, heated steam is continuously supplied into the cleaning tank 12. In particular, the water supply time T by the water supply valve 67 is controlled to be longer as the water supply interval TA (elapsed time from the previous water supply operation) is shorter, and the water supply time during the previous water supply operation is shorter. It is shortened as the state is increased. In FIG. 4, the relationship between the temperature detected by the thermistor 49 and the reference temperature is also shown.

According to the configuration of the present embodiment described above, the following operations and effects can be achieved.
That is, as in the present embodiment, an injection nozzle 20 for injecting cleaning water into the outer tub 13 toward the cleaning tank 12 and the dishes stored in the tableware baskets 19a, 19b in the cleaning tank 12, and In the dishwasher 11 provided with 22, there is a circumstance that there is a space (gap) that becomes a dead space between the bottom of the washing tank 12 and the bottom of the outer box 13. In this embodiment, an integrated body of an aluminum steam generation unit 40 formed in a sealed container shape having a water supply port 44 and a steam discharge port 45 and a sheathed heater 47 capable of heating the unit 40 is referred to as the dead space. Therefore, the presence of the steam generation unit 40 and the sheathed heater 47 is not likely to cause a deterioration in volumetric efficiency related to the cleaning tank 12. In addition, the steam generated by heating the water supplied from the water supply port 44 in the steam generation unit 40 is supplied to the cleaning tank 12 through the steam discharge port 45 and the spout 57 opened in the cleaning tank 12. As a result, a structure capable of performing a steam process of supplying heated steam into the cleaning tank 12 to improve the cleaning efficiency without causing deterioration in volumetric efficiency. Can be realized.

  In the steam process as described above, since a large amount of heated steam can be supplied into the washing tank 12 in a short time, the swelling effect (and the peeling effect) of dirt stuck to the tableware is enhanced, and thereafter Thus, the cleaning efficiency in the cleaning process carried out in (1) can be greatly improved.

  In this case, the control microcomputer 64 in the control circuit unit 55 keeps the water supply means for a predetermined time each time when the water supplied to the steam generation unit 40 is all evaporated by the water supply valve 67 during the execution of the steam process. It is the structure which performs the water supply operation | movement which operates only, ie, the intermittent water supply operation | movement. In such a configuration, variations in the output of the sheathed heater 47 (variations due to fluctuations in the power supply voltage, etc.), or variations in the amount of water supplied per unit time by the water supply valve 67 (variations in water supply performance, tap water pressure, etc.) In particular, when the output of the sheathed heater 47 is relatively high or when the amount of water supplied per unit time is relatively small, the water supplied into the steam generating unit 40 is short. Since it evaporates over time, a phenomenon occurs in which the temperature of the steam generation unit 40 becomes higher than normal and the number of operations of the water supply valve 67 increases.

  In the present embodiment, the control microcomputer 64 has the water supply time T (the operation time of the water supply valve 67) in a state where all the water supplied into the steam generation unit 40 has evaporated after the water supply into the steam generation unit 40. Time, i.e., when the water supply interval TA is shorter, the control is performed so as to be longer. Therefore, the variation in the output of the sheathed heater 47 and the amount of water supplied per unit time by the water supply valve 67 are changed. Even when there is a variation, there is no possibility that the time until the water supplied into the steam generating unit 40 evaporates is inadvertently shortened.

  As a result, it is possible to prevent the occurrence of a phenomenon in which the temperature of the steam generation unit 40 becomes higher than normal and a phenomenon in which the number of operations of the water supply valve 67 increases. This eliminates the need to select an expensive material having high heat resistance for the components (heat resistant packing 43, etc.) and the support structure of the steam generating unit 40, and an expensive material having excellent durability as the water supply valve 67. Since there is no need to make a selection, the manufacturing cost can be reduced. In addition, it is possible to prevent a situation in which the amount of water supply per unit time is relatively large, that is, a situation in which the degree of temporary temperature decrease of the steam generation unit 40 is large, and thus the generation of heated steam becomes unstable. And the supply of heated steam can be continued in a stable state. Moreover, since the situation where the amount of water supply per unit time is relatively increased can be prevented in advance, a part of the water supplied into the steam generation unit 40 does not become steam, and the steam generation unit 40 The possibility of being discharged from the vapor discharge port 45 into the cleaning tank 12 is reduced, and the generation of such noise due to the discharge of water can be prevented.

  The control microcomputer 64 is configured to perform control to shorten the water supply time T when the water supply time at the previous water supply operation is short when the water supply time T is controlled by the water supply valve 67 as described above. Therefore, a situation where the water supply time T becomes unnecessarily long can be prevented.

  Further, the thermistor 49 necessary for performing the control as described above is configured to detect the bottom temperature of the steam generating unit 40, that is, the temperature of the heating dish 41a. Can be accurately detected, which is beneficial in efficiently performing the steam process as described above.

  According to the present embodiment, the water supply port 44 and the steam discharge port 45 of the steam generation unit 40 and the water supply valve and the discharge port 57 (not shown) are connected via the tubes 56 and 58 having flexibility and heat resistance. Therefore, the degree of freedom related to the arrangement of the steam generation unit 40 can be increased without being greatly affected by the positions of the water supply valve and the outlet 57 (not shown), and the piping structure for the steam generation unit 40 Can be simplified.

  In the present embodiment, the steam generation unit 40 includes a container-like main body 41 provided with a heating dish 41a and a lid 42 that hermetically closes the upper surface opening of the main body 41, and the lid 42 On the side (that is, the upper surface side of the steam generation unit 40), the water supply port 44 and the steam discharge port 45 provided with cylindrical bodies 44a and 45a are provided. For this reason, in particular, with respect to the vapor discharge port 45, the space between the cylindrical body 44a and the lower end portion of the cylindrical member constituting the jet outlet on the cleaning tank 12 side (the part protruding downward from the bottom of the cleaning tank 12). The connection by the tube 58 can be easily performed, and the flow of the heated steam through the tube 58 can be kept in a good state. Incidentally, assuming a structure in which the steam discharge port 45 is provided on the lower surface side of the steam generation unit 40, in this structure, the tube 58 has a U-shaped arrangement, so that dew condensation is formed in the middle part which is the lowermost part. The problem is that water tends to accumulate, and the flow of heated steam becomes worse. In addition, since the cylindrical bodies 44a and 45a should just be provided in the form orthogonal to the upper surface of the cover part 42, there is no possibility that the mold structure at the time of die-casting the cover part 42 will be complicated.

  The main body 41 of the steam generating unit 40 is formed in a flat rectangular (rectangular) container shape, and the recess in the main body 41 is configured to function as a heating pan 41a for generating heated steam, The heating dish 41 a has a shape extending in the longitudinal direction of the steam generation unit 40. Further, the water supply port 44 and the steam discharge port 45 are formed in a state of being spaced apart from each other in the longitudinal direction at a position facing the heating dish 41a from above, and the bottom of the heating dish 41a is the steam discharge port 45 from the water supply port 44 side. It is formed in the shape inclined downward as it goes to the side. Accordingly, since the water flowing into the heating dish 41a from the water supply port 44 spreads quickly over the entire heating dish 41a, the steam generation efficiency by the sheathed heater 47 located on the back side of the heating dish 41a is improved. As a result, a large amount of heated steam can be generated quickly. Further, since the heat radiating fins 48 and 52 are integrally formed on the heating pan 41a, it is useful for increasing the generation efficiency of the heating steam, and a reheating function of the generated heating steam can be obtained. .

  At the bottom of the heating pan 41a, a step portion 41b is formed in a portion that faces the water supply port 44 from below and rises from the other portion. The situation that scatters around is suppressed as much as possible. Therefore, it is useful in preventing a situation (a situation where the water supply port 44 is clogged) that scales due to calcium carbonate or the like contained in the heated water are generated around the water supply port 44. In addition, at a position corresponding to the water supply port 44 on the lower surface of the lid portion 42, a partition wall portion 44b having a semicircular cross-section having a shape surrounding the water supply port 44 from the direction of the heating dish 41a is integrated so as to protrude downward. Since it is formed, the partition wall portion 44b functions to suppress the situation where bump water is scattered around the water supply port 44, and can contribute to the prevention of scale generation as described above. In addition, since the upper surface of the step part 41b is formed in the structure inclined downward as it goes to the center part direction of the heating tray 41a, the water which flows in from the water supply port 44 can suppress jumping.

  The spout 57 provided for supplying the heated steam generated by the steam generating unit 40 into the cleaning tank 12 is formed by a cylindrical member 57a having a shape penetrating the bottom of the cleaning tank 12 in the vertical direction. Yes. In this case, the protruding portion of the cylindrical member 57a into the cleaning tank 12 covers the upper end opening (that is, the jet outlet 57) of the cylindrical member 57a from above, and is positioned below the upper end opening. Since the cover member 59 in which the opening 59a serving as a water vapor passage is formed is provided, there is no possibility that the cleaning water and bubbles in the cleaning tank 12 flow into the steam generation unit 40 through the jet outlet 57. It is possible to prevent the inside of the steam generation unit 40 from becoming dirty.

  The steam generation unit 40 in a state where the sheathed heater 47 is embedded in an embedded state is provided with the first support plate 2 and the first support plate 2 configured to suppress heat conduction with respect to the attachment site in the outer box 13 (outside the bottom surface of the cleaning tank 12). Since it is attached via the second support plate 61, it is possible to effectively prevent a situation where at least the bottom wall portion is adversely affected by heat with respect to the cleaning tank 12 formed of synthetic resin. In addition, since the first heat shield plate 62 and the second heat shield plate 63 for shielding the radiant heat from the steam generating unit 40 are provided, it is possible to prevent a situation in which an adverse effect due to the radiant heat occurs.

  The steam discharge port 45 of the steam generation unit 40 is provided at a position corresponding to the portion where the heating energy by the sheathed heater 47 is most concentrated in the unit 40, so that the steam generated in the heating dish 41 a is discharged from the steam. The final heating can be performed in the vicinity of the outlet 45, and heated steam having a high momentum can be discharged from the vapor discharge port 45.

(Second Embodiment)
FIG. 14 shows a second embodiment (corresponding to claim 3) of the present invention in which a change is made to the first embodiment. Hereinafter, only portions of the second embodiment different from the first embodiment will be described. explain.
That is, in this second embodiment, the control microcomputer 64 determines the water supply time T in each water supply operation by the water supply valve 67, and the water supply time determination table as shown in FIG. The water supply operation is determined based on the water supply time determination table as shown in FIG. 14B during the third and subsequent water supply operations (the water supply time during the first water supply operation is the first implementation. 1.5 seconds as in the example). That is, the control microcomputer 64 performs the control for shortening the water supply time T in the new water supply operation as the water supply time T in the previous water supply operation is shorter, and the water supply operation by the water supply valve 67 is performed a predetermined number of times. The configuration starts when the number of times becomes three or more.

  According to the present embodiment having such a configuration, it is possible to finely control the water supply time T during each water supply operation, which is beneficial for continuing the supply of heated steam in a stable state.

(Other embodiments)
The present invention is not limited to the embodiments described above and shown in the drawings. For example, the following modifications or expansions are possible.
In the above-described embodiment, the bottom portion of the heating dish 41a is formed to have a structure that is inclined downward as it goes from the water supply port 44 side to the steam discharge port 45 side. Therefore, when the steam generation unit 40 itself is arranged obliquely, the inclined structure as in this embodiment is not necessary.

  Although the sheathed heater 47 is provided integrally with the steam generating unit 40, it is needless to say that it may be provided separately. In addition, although the steam generation unit 40 is made of aluminum, it may be made of other metal or ceramic.

The flowchart which shows the control content by the control microcomputer in 1st Example of this invention. The figure which shows an example of the table for water supply time determination Functional block diagram showing electrical configuration Timing chart for action explanation Vertical section of a dishwasher Perspective view showing the appearance of the dishwasher with the door open The perspective view which shows the external appearance of the dishwasher in the state which closed the door Enlarged longitudinal section of the main part Perspective view of steam generation unit Vertical section of steam generation unit Bottom view of the steam generator unit body A perspective view of the main body of the steam generating unit Exploded perspective view showing the mounting and fixing structure of the steam generating unit FIG. 2 equivalent diagram showing a second embodiment of the present invention.

Explanation of symbols

  11 is a dishwasher, 12 is a washing tank, 13 is an outer box, 20 is an injection nozzle (cleaning means), 22 is a rotary injection nozzle (cleaning means), 40 is a steam generating unit, 41 is a main body, and 41a is heated Plate, 42 lid portion, 43 heat resistant packing, 44 water supply port, 45 steam outlet, 47 sheath heater (heat source), 49 thermistor (detection means), 55 control circuit unit, 56 tube, 57 Indicates a jet port, 64 indicates a control microcomputer (control means), and 67 indicates a water supply valve (water supply means).

Claims (3)

In the dishwasher provided with cleaning means for spraying cleaning water toward the cleaning tank and the dishes accommodated in the cleaning tank in the outer box,
A steam generation unit formed in a closed container shape having a water supply port and a steam discharge port, and disposed in a space between the bottom of the cleaning tank and the bottom of the outer box;
A heat source disposed in the space so as to heat the steam generation unit;
A spout formed in the cleaning tank so as to open in the tank;
Water supply means for supplying water through the water supply port into the steam generation unit in an operating state;
Detecting means for detecting a state in which all of the water supplied into the steam generating unit is evaporated by the water supply means;
Control means for operating the water supply means for a predetermined time each time the detection means enters a detection state;
With
The steam generated in the steam generation unit is configured to be supplied from the steam discharge port to the cleaning tank through the jet port,
The control means performs control to change the operation time of the water supply means so that the operation time after the water supply to the steam generation unit is increased as the time until the detection means enters the detection state is shorter. And dishwasher.   The said control means performs control which shortens the operation time of the said water supply means in the new water supply operation, so that the operation time of the said water supply means in the last water supply operation is short. Dishwasher. The dishwasher according to claim 2,
The said control means starts the control which shortens the said water supply operation time, when the frequency | count of implementation of the water supply operation | movement by the said water supply means becomes more than predetermined number, The dishwasher characterized by the above-mentioned.

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