JP2532441B2 - Load detection device for washing machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing machine for detecting the amount of clothes put in a washing tub, a dewatering tub, or a washing / dehydrating tub by arithmetic processing by an electronic control unit such as a microcomputer. The present invention relates to a load amount detection device.

2. Description of the Related Art Conventionally, many load amount detecting devices of a washing machine for detecting a load amount have been provided. For example, there is a load detection device disclosed in Japanese Patent Publication No. 61-22598. As shown in FIG. 7, this load amount detecting device includes a washing motor 2 for selectively driving a stirring blade and a washing / dehydrating tub as switching means 4a, 4a.
It is connected to the AC power source 1 via b, and the capacitor 3 is connected between the windings of the washing motor 2. Switching means 4a, 4b is a signal is sent from the control circuit 5 to the gate G _1, G _2, on based on the signal to turn off. A current transformer 6 is connected to the motor 2, and the output of the current transformer 6 is input to the control circuit 5. And the control circuit 5 uses the switching means 4a, 4
The washing motor 2 is started by controlling b, the current value of the washing motor 2 after a fixed time thereafter is detected, and the load amount is determined by the current value. According to this configuration, the current value detected as the load amount data changes due to the voltage fluctuation of the power supply 1, so that the load amount cannot be accurately detected.

Therefore, a load amount determining device for a washing machine disclosed in Japanese Patent Laid-Open No. 57-136484 is provided. That is, this load amount determination device detects the power supply voltage and corrects and determines the load amount based on the fluctuation of the detected power supply voltage.

Problems to be Solved by the Invention However, in the conventional configuration, the change in the motor current or voltage at the start-up and startup of the motor is detected. The load amount could not be detected.
In other words, since the characteristics of this motor affect the motor current and voltage when the motor is energized, the conventional detection method that detects the load when the motor is energized detects the load accurately without being affected by the characteristics of the motor. It was impossible.

In view of the above problems, it is an object of the present invention to improve detection accuracy without being affected by variations in motor characteristics.

Means for Solving the Problems In order to achieve the above object, a load detection device for a washing machine according to the present invention includes a motor for driving a washing / dehydrating tub or a stirring blade, and a main coil and an auxiliary coil of the motor. A connected capacitor, a triac connected between the motor and an AC power supply, control means for controlling the energization of the motor via the triac, and pulse generation for generating a pulse according to the capacitor voltage change The control means energizes the motor for a predetermined time, and determines the load amount based on the number of pulses from the pulse generating means within the OFF period immediately after that.

Action With the above configuration, the load amount is determined by detecting the number of pulses according to the motor capacitor voltage change when the motor is not energized, so it is possible to prevent variations in detection accuracy due to variations in motor characteristics and to detect only the number of pulses. Therefore, the control unit can also accurately determine the load amount with a simple configuration. When a command is given to the triac to stop the energization of the motor, it continues to be energized until the current of the AC power supply becomes zero due to the characteristics of the triac. Therefore, the capacitor voltage that is out of phase with the current of the AC power supply becomes a peak voltage when the current is zero, and the load amount can be accurately detected by detecting the attenuation after reaching the peak voltage.

Embodiments Embodiments of the present invention will be described below with reference to FIGS. 1 to 6.

As shown in FIG. 1, the control unit of the fully automatic washing machine in this embodiment is connected to an AC power source 1 and a washing motor 2 for selectively driving a stirring blade and a washing / dehydrating tub. A condenser 3 is connected between the main coil and the auxiliary coil of the washing motor 2. Capacitor 3 terminal and AC power supply 1
Semiconductor switching devices 4a and 4b, which are one of switching devices, are connected between them. Semiconductor switching device 4a,
4b is usually composed of a bidirectional 3-terminal thyristor (hereinafter referred to as a triac). When the triac 4a conducts, the washing motor 2 rotates forward, and when the triac 4a is turned off and the triac 4b is turned on, the washing motor 2 is rotated in the reverse direction.
The control circuit 5A receives instructions from the operation keys, a signal from the lid switch 50, the water level detection device 5B, etc., and the triacs 4a, 4b for driving the washing motor 2, the magnet 7 for the drain valve, and the triac 4c for driving the water supply valve 8. Controls 4d switching. The pulse generating means 5C detects the terminal voltage of the capacitor 3 of the washing motor 2 and generates a pulse according to the change of this voltage. The terminal voltage of the capacitor 3 has a correlation with the motor rotation speed, and during the rest period before conducting the triac 4a or 4b and then reversing the rotation,
The capacitor voltage attenuates according to the rotation speed. FIG. 2 shows a change in the terminal voltage of the condenser 3 when the washing motor is switched to the stirring blade side and the triac 4a or 4b for driving the washing motor 2 is turned off. A is the case where the load is small and the reduction rate of the motor rotation speed is small, and B
On the contrary, the load is large and the motor rotation speed decreases rapidly. During the normal rotation / reverse rotation control period of the washing motor 2, the triacs 4a and 4b are both in the off state, so the voltage across the terminals of the capacitor 3 should be O, but due to the rotation of the washing motor due to inertia, the main coil, An induced voltage is generated in the auxiliary coil, and the induced voltage decreases as the rotation speed decreases, and the waveform becomes as shown in FIG. When the load amount is large, the motor speed rapidly decreases and the capacitor voltage also decreases, so that the load amount such as the cloth amount can be detected. Moreover, even if an off command is output to the triac, the triac has a characteristic of maintaining the energized state until the current of the AC power supply 1 becomes zero. Therefore, even if an off command is issued to the triac, the motor 2 continues to be energized until the AC power supply 1 becomes zero, so that the terminal voltage of the capacitor 3 of the motor 2 reaches the peak voltage. That is, the inter-terminal voltage of the capacitor 3 reaches the peak voltage when the current of the AC power supply 1 is zero, and the timing of stopping the energization of the AC power supply 1 (the timing of issuing the OFF command to the triac) is the AC power supply 1 Since the voltage across the terminals of the capacitor 3 always reaches the peak voltage even when the current does not reach zero, the capacitor 3 starts discharging after reaching this peak voltage and the induced voltage also gradually decreases. The voltage waveform is as shown. In this way, be sure to use capacitor 3
Since the attenuation after the terminal voltage of has reached the peak voltage is detected, the detection accuracy can be improved.

FIG. 3 shows the details of the pulse generating means 5C. That is,
A resistor 501, a diode 502, and a photocoupler 503 series circuit are used as input sides, and are connected to both sides of the capacitor 3.
NPN the transistor emitter terminal of the photo coupler 503.
Connected to the base terminal of the transistor 504 and connected to Darlington. A resistor 505 is connected between the base and emitter of the transistor 504. Transistor 506 has a resistor of 50
It is connected to the base terminal of the PNP transistor via 6 and the signal output V ₀ is output to the collector resistance 509 of which the waveform is shown in FIG. FIG. 4 shows the capacitor terminal voltage V _c and the signal output V _{0. When} the capacitor voltage V _c becomes O, the signal output
V ₀ also becomes L ₀ level. The number of pulses of the capacitor voltage V _c is measured by detecting the change in the signal output, that is, the edge of the pulse.

Next, the flow of load amount determination will be described with reference to FIG. That is, after the initial setting in step 52, the water level is set low. Water supply is started in step 53, and it is determined in step 54 whether or not the set water level has been reached. When it is determined that the water level is the set water level in step 54, the water supply is stopped in step 55 and the stirring blades are rotated to start washing. The load amount is determined in step 26 while the forward and reverse inversions are stirred 20 to 30 times. There is no such judgment.
This is performed by measuring the number of pulses due to a change in the terminal voltage of the capacitor 3 while the washing motor 2 is at rest. Further, this load amount determination will be described in detail with reference to FIG. That is, when the load amount determination routine is entered, it is determined in step 551 whether the washing motor 2 is on or off. If the washing motor 2 is turned on whether the motor on time t _on has elapsed it is determined at step 552, and repeats the above operation to return to step 552 if not elapsed motor on time t _on. If the motor _on time t _on has elapsed, the washing motor is turned off in step 553, the counting time t is set to O, the number of pulses (the number of edges of the signal V ₀ ) N is set to O, and the process returns to step 551. If it is determined in step 551 that the washing motor 2 is off, step 554
Input the signal V ₀ with. This signal V ₀ is a pulse, so H
The signal input timing is at least 7 msec or less, and 2 to 4 msec is suitable. Then, the H or L signal is transferred to the temporary data P ₁ (step 555). Next, in step 556, it is determined whether or not the previous temporary data P _{0 and} this P ₁ are equal, and if they are not equal, one pulse number N is added in step 557. If they are equal, the data of P ₁ is replaced with P ₀ in step 558. After adding the pulse number N in step 557, the data is similarly replaced in step 558. After this, step 559
Then, it is determined whether or not the off time t _off of the washing motor 2 has passed. If not, the process returns to step 551 and the same control as above is performed. If the predetermined time has elapsed, the washing motor 2 is turned on in step 561, and then the counting time t is set to O in step 562, and the pulse number N within one motor _off time t _off is newly added to the integrated pulse number N ₁ . . After this, step 551
Return to and repeat the above operation. When the washing motor 2 is reversed, the washing motor 2 is repeatedly turned on and off, and the load amount is judged by the cumulative number of pulses N ₁ after the turning on and off a predetermined number of times, and the water level, water flow, washing time, rinsing time, Set the dehydration time and control the process.

For example, when the integrated pulse number N ₁ is small and the load is large, process control such as increasing the washing time and rinsing time, changing the water level to a high value and strengthening the water flow, and conversely N ₁
As the amount of water increases, the process control such as shortening the washing and rinsing time, lowering the water level and weakening the water flow is performed. In addition, the load amount is determined by the cumulative number of pulses N _{1, the} number of pulses N obtained during one washing motor off time is statistic, and thus the load amount can be determined by more averaged data. It is possible to perform highly accurate detection with little variation.

Although the pulse is generated according to the change of the capacitor voltage of the motor in this embodiment, the pulse may be generated according to the change of the voltage induced in the winding of the washing motor, for example. It suffices to detect the portion affected by the induced voltage. Further, the load amount may be determined by the number of pulses generated according to the change in the induced voltage immediately after the motor that rotates the washing / dehydrating tub is turned on without being measured during the down time of the stirring blade. In this case, when the load amount is large, the pulse number is large, and when the load amount is small, the pulse number is small.

Further, in the present embodiment, the case of a fully automatic washing machine is shown,
Even in the two-tub type washing machine, the load amount can be similarly detected by counting the pulses according to the induced voltage changes of the washing motor of the washing machine and the dehydration motor of the dehydration tub.

EFFECTS OF THE INVENTION As is clear from the above embodiments, according to the present invention, the motor is driven for a certain period of time and the number of pulses generated according to the change in the capacitor voltage of the motor immediately after being turned off is measured to measure the load. Since the amount is detected, the load amount can be detected with high accuracy without being affected by the variation in the characteristics of the motor. In addition, since the induced voltage is converted into a pulse and the control means detects the load amount only by counting the number of pulses,
It is possible to simplify the configuration of the load amount detection unit, and particularly when the control means is configured by a microcomputer, a program that only counts the number of pulses is sufficient, and the load amount detection program can be sufficiently executed within the limited capacity of the control program. Can be added. In particular, as in the present invention, the induced voltage during the off-time of the motor generates an AC voltage, so that the pulse generating means has a simple structure, and is extremely effective as a load amount detecting device for an electronic washing machine. Also, when a command is given to the triac to stop energizing the motor, the current continues to flow until the current of the AC power supply becomes zero due to the characteristics of the triac, so the attenuation after the capacitor voltage reaches the peak voltage is the number of pulses. It is possible to detect, and it is possible to improve the load amount detection accuracy due to the attenuation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a load amount detecting device for a fully automatic washing machine and its control circuit in one embodiment of the present invention, and FIG. 2 is a view immediately after driving a motor to turn it off. FIG. 3 is a circuit diagram of the pulse generating means, FIG. 4 is a waveform diagram of an input / output portion of the pulse generating means, and FIGS. 5 and 6 are diagrams of the load amount detecting device. FIG. 7 is a flow chart showing control, and is a block diagram of a conventional load amount detecting device. 2 ... Washing motor, 3 ... Capacitor, 4a-4d ... Switching device, 5A ... Control circuit, 5C ... Pulse generating means.

Claims (1)

(57) [Claims] 1. A motor for driving a washing / dehydrating tub or a stirring blade, a capacitor connected between a main coil and an auxiliary coil of the motor, a triac connected between the motor and an AC power supply, A control means for controlling the energization of the motor through a triac; and a pulse generation means for generating a pulse according to the change in the capacitor voltage,
The load amount detection device for a washing machine, wherein the control unit energizes the motor for a predetermined time and determines the load amount based on the number of pulses from the pulse generation unit within an off period immediately after that.