JP2005342424A - Dishwasher - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dishwasher in which the cavitation sound of a drain pump is small and drain time is short in the entire draining process. <P>SOLUTION: In the dishwasher, a control means for controlling water supplying, cleaning and drain process performs control so as to drive the drain pump for prescribed time by a first number of rotations first and drive the drain pump by a second number of rotations lower than the first number of rotations thereafter and sets the time of driving it by the first number of rotations corresponding to the time in which water is additionally supplied for the prescribed time after detecting a water level in a water level detection means in the water supplying process immediately before the draining process. In the dishwasher, in the draining process executed after the cleaning process of a washing process or a rinsing process, the time of driving the drain pump by the higher number of rotations is prolonged as a supply water amount is larger and thus the total drain time does not become different so much. Additionally, the time until the cavitation is longer when the supply water amount is larger and the cavitation sound does not become big during drive by the high number of rotations, it is useful for the dishwasher installed in a place where noise is disliked. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dishwasher for cleaning dishes by spraying water by rotationally driving a nozzle disposed in a washing tank.

  Conventionally, an example of the structure of this type of dishwasher is shown in FIG. In FIG. 6, a water supply means 22 for supplying water to the side surface of the cleaning tank 21 and a water level detection means 23 for detecting a plurality of water levels of the supplied water are provided. A cleaning nozzle 24 for injecting water, a cleaning pump 25 for supplying water under pressure toward the cleaning nozzle 24, and a drainage pump 26 for draining water out of the cleaning tank 21, and these are controlled on the side thereof. Control means 27 is provided (see, for example, Patent Document 1).

In the drainage process, the control means 27 measures the water level decrease time between the two water levels by the water level detection means 23 for detecting a plurality of washing water levels, thereby estimating the capacity of the drainage pump 26 and eliminating the flushing water. The amount of time that the air is mixed (hereinafter referred to as air biting) is predicted, and the rotational speed of the drainage pump 26 is reduced before that time, thereby preventing the air biting noise from increasing during drainage. Yes.
JP-A-3-215230

  In recent years, water saving has become important in dishwashers, and the washing water level has become considerably low. Since the water level detection means 23 for detecting a plurality of washing water levels according to the prior art has almost no difference in water level, it is difficult to implement. It has become. Also, from the viewpoint of cost, it is possible to make the water level detecting means of one point water level, for example, a float switch, etc. much cheaper, so this water level detecting method is almost adopted.

  However, in order to ensure the cleaning performance, the washing water level in the washing process must be set high, and the washing water level in the rinsing process must be set low, so that the water supply means 22 supplies water in the water supply process in the washing process, and the water level detection means Even after the one-point water level is detected at 23, additional water is supplied for a predetermined time to increase the amount of water supplied.

  However, when the number of revolutions of the drainage pump 26 is lowered from a high number of revolutions to a low number of revolutions in a certain time in the drainage process, the air biting noise of the drainage pump 26 increases due to the difference in the amount of supplied water after washing in the washing process. Or, conversely, there was a problem that the air biting noise was small and the drainage time was long.

  In view of the above-described conventional problems, an object of the present invention is to provide a dishwasher in which all the drainage steps have a low noise noise of a drainage pump and a short drainage time.

  To achieve the above object, a dishwasher according to the present invention is supplied to a washing tank, a water supply means for supplying water into the washing tank, a water level detection means for detecting the water level in the washing tank, and the washing tank. The water pump pressurizes and circulates the water through the nozzle in the washing tank, the drain pump that drains the water outside the washing tank, and the water level detection means, and the water supply means, the washing pump, and the drain pump as outputs. And a control means for controlling the water supply / washing / drainage process. The control means first drives the drainage pump at a first rotation speed for a predetermined time in the drainage process, and then a second lower than the first rotation speed. Controls to drive the drainage pump at the number of revolutions, and sets the time to drive at the first number of revolutions according to the time of additional water supply for a predetermined time after detecting the water level in the water supply process immediately before the drainage process. Configured to Than it is.

  According to the above configuration, when additional water is supplied in the washing process or the rinsing process and the water level is high, the draining process immediately after the draining process can take a long time to drain at a high rotational speed.

  According to the dishwasher of the present invention, in the drainage process performed after the washing process of the washing process or the rinsing process, the longer the time for driving the drainage pump at a higher rotational speed as the amount of supplied water increases, the total drainage time There is not much difference. In addition, as the amount of supplied water increases, the time until the air bites becomes longer, and the air biting noise does not increase during driving at a high rotational speed.

  Hereinafter, a dishwasher according to an embodiment of the present invention will be described with reference to FIGS.

  In FIG. 1, a water supply means 3 having a water supply valve 2 for supplying water to the lower part of a cleaning tank 1 and a one-point water level detection type water level detection means 4 for detecting the water level of the supplied water are provided. A dish basket 5 for storing dishes, and a cleaning nozzle 6 is provided at the lower part of the dish basket 5. The cleaning nozzle 6 rotates and sprays water onto the dishes to wash the dishes. A heater 7 for heating the cleaning water is disposed below the cleaning nozzle 6. In order to detect the heating state of the heater 7, temperature detecting means 8 for detecting the temperature in the cleaning tank is provided so as to stick to the lower outer surface of the cleaning tank 1.

  A cleaning pump 9 is connected to the cleaning nozzle 6 to circulate water in the cleaning tank 1 through the cleaning nozzle 6. A drainage pump for draining water to the outside of the machine is shared with the washing pump 9, and functions as the washing pump 9 when the pump motor 10 rotates in the forward rotation direction. Switch) to function as a drainage pump 9.

  A control means 11 for controlling the water supply valve 2 and the pump motor 10 is provided next to the washing and draining pump 9. FIG. 2 is a circuit diagram showing the configuration of the control means 11. The same components as those in FIG.

  In FIG. 2, the control means 11 is usually constituted by a one-chip microcomputer (hereinafter referred to as a microcomputer), a read-only storage means ROM (not shown) storing a program therein, and a read / write storage means RAM (not shown). And a timer for measuring time as part of the program. Further, loads such as the water supply valve 2 and the heater 7 are driven by supplying a commercial AC power supply 13 by the power switching means 12 constituted by a bidirectional thyristor and a relay. In this embodiment, the pump motor 10 for driving the washing and draining pump 9 can easily control the rotation speed, and a large torque can be obtained at the time of starting and in a low speed region, so that a DC brushless motor is used.

  In order to drive the pump motor 10 composed of this DC brushless motor, the commercial AC power supply 13 is converted to DC by a DC power conversion circuit 14 including a rectifying diode bridge 14a, a noise preventing choke coil 14b, and a smoothing capacitor 14c. , Supplied to the inverter circuit 15. The inverter circuit 15 is constituted by a switching element of a direct current power source composed of a parallel circuit of a power transistor and a reverse conducting diode, and is connected to the pump motor 10. The pump motor 10 includes a stator having three-phase windings 10a (U phase), 10b (V phase), and 10c (W phase), and 2n pole (n is a natural number) permanent magnets on the ring. It is comprised from a rotor (not shown). Further, the current detection means 16 is connected to the negative voltage side of the inverter circuit 15, and the current flowing through the U, V, W phase lower arms of the inverter circuit 15 is detected, so that the output current of the inverter circuit 15, that is, the pump Each phase current of the motor 10 is detected.

  Here, the driving of the pump motor 10 by the control means 11 calculates the output current of the inverter circuit 15 from the output signal of the current detection means 16, and applies pulse width modulation (hereinafter referred to as PWM) to a predetermined frequency and a predetermined voltage according to the set rotational speed. The pump motor 10 can be driven at a set synchronous speed by controlling the output current phase with respect to the output voltage to be a reactive current according to the load of the pump motor 10.

  FIG. 3 is a diagram showing a control sequence of the dishwasher according to the present embodiment. The washing process 17 includes a water supply process 17a, a cleaning process 17b, and a drainage process 17c. The rinsing process includes rinsing 1 (18), rinsing 2 (19), and rinsing 3 (20), and the sequence shifts from the left end to the right. go. Further, the rinsing process will be described in detail. Rinse 1 (18) includes a water supply process 18a, a cleaning process 18b, and a drainage process 18c. Similarly, Rinse 2 (19) includes a water supply process 19a, a cleaning process 19b, and a drainage process 19c. The rinse 3 (20) includes a water supply process 20a, a cleaning process 20b, and a drainage process 20c.

  FIG. 4 is an operation flowchart in the water supply process 17a, 18a, 19a, 20a of the microcomputer as the control means 11. First, when the process proceeds to the water supply process, the water supply valve 2 is driven in step S1, and it is determined whether or not the water level detecting means 4 is turned on in step S2, and the water supply valve 2 is continuously driven until turned on. When the water level detection means 4 is turned on, it is determined whether or not the washing process is in a step S3, and if it is a washing process, an additional water supply time Tm = 5 seconds is set in a step S4. If it returns to step S3 and it is other than a washing process, additional water supply time Tm = 0 second will be set by step S5.

  Next, the water supply valve 2 is continuously driven until the Tm seconds elapse in step S6. By the processes of steps S3 to S6, additional water is supplied for 5 seconds only in the washing process. Next, the additional water supply time Tm of this water supply process is memorize | stored at step S7, and also it transfers to the following washing | cleaning process at step S8.

  In the flowchart of FIG. 4, the additional water supply is performed only for the washing process for 5 seconds. However, in order to obtain the rinsing effect in the final rinsing 3 (20) of the rinsing process of FIG. In this case, what is necessary is just to set the value of the additional water supply time Tm according to the frequency | count of rinsing by step S5 of FIG.

  FIG. 5 is an operation flowchart in the draining process 17c, 18c, 19c, 20c of the microcomputer as the control means 11. First, when the process proceeds to the drainage process, the pump motor 10 is driven at 3000 [r / min] in step S9, and the value of Tm stored in the previous water supply process is read in step S10 to determine whether it is 5 seconds or longer. If it is 5 seconds or more, 20 seconds is set as the time t for driving the pump motor 10 at 3000 [r / min] in step S11. Returning to step S10, if it is less than 5 seconds, t is set to 10 seconds in step S12.

  Next, the pump motor 10 is continuously driven at 3000 [r / min] until t seconds elapse in step S13. Only when additional water is supplied for 5 seconds in the previous water supply process by the processes of steps S10 to S13, the time for driving the pump motor 10 at 3000 [r / min] becomes longer. Next, the rotational speed of the pump motor is reduced to 1500 [r / min] in step S14, and further, in step S15, the motor is continuously driven at 1500 [r / min] for a predetermined time, for example, 40 seconds, and the next water supply is performed in step S16. The process proceeds (in the case of rinse 3, the process is terminated).

  In the present embodiment, the drainage pump is integrated with the cleaning pump and shared, but it is also effective to use a separate pump.

By controlling the driving of the pump motor in the above operation, the time for driving the drainage pump at a higher rotational speed is increased as the amount of supplied water is increased, so there is not much difference in the total drainage time.
In addition, when the air is biting, the air biting sound does not increase because it is driven at a low rotational speed.

  In the dishwasher of the present invention, in the drainage process performed after the washing process of the washing process or the rinsing process, the longer the time for driving the drainage pump at a higher rotational speed as the amount of supplied water is larger, the more the total drainage time is reduced. There is no difference. In addition, as the amount of water supplied increases, the time until the air bites becomes longer, and the air biting noise does not increase during driving at a high rotational speed, so it is useful for dishwashers installed in places where noise generation is averse. .

The longitudinal cross-sectional view which shows schematic structure of the dishwasher of one Embodiment of this invention. The circuit diagram which shows the structure of the control means in the dishwasher. Explanatory drawing of the control sequence from the washing process of the dishwasher to a rinse process. The flowchart which shows the control procedure of the water supply process of the dishwasher. The flowchart which shows the control procedure of the drainage process of the dishwasher. The longitudinal cross-sectional view which shows schematic structure of the conventional dishwasher.

Explanation of symbols

1 Washing tank 3 Water supply means 4 Water level detection means 6 Washing nozzle 9 Washing pump (drainage pump)
10 Pump motor 11 Control means

Claims (1)

  A cleaning tank, a water supply means for supplying water into the cleaning tank, a water level detection means for detecting the water level in the cleaning tank, and the water supplied to the cleaning tank is pressurized and circulated through a nozzle in the cleaning tank. A cleaning pump for draining water out of the cleaning tank, and a control means for controlling the water supply / cleaning / drainage process with the water level detection means as an input and the water supply means, the cleaning pump and the drainage pump as an output. The control means controls to drive the drain pump at a first rotation speed for a predetermined time in the drainage process for a predetermined time, and then drives the drainage pump at a second rotation speed lower than the first rotation speed. A dishwasher configured to set the time for driving at the first rotational speed in accordance with the time of additional water supply for a predetermined time after the water level is detected by the water level detection means in the water supply step immediately before.

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