JP2013103054A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect detergent foam entering a hot air blowing passage to prevent failure of a washing machine.SOLUTION: In a washing machine, a foam detection sensor 70 provided in a hot air blowing passage 49 in the vicinity of a warm air blast port 51 formed in a lower portion of a back face of a water reception tank 33 includes a light emitting element 70b and a light-receiving element 70a arranged so as to face each other perpendicular to an axis center line of the hot air blowing passage 49 in the outside of the hot air blowing passage 49. Control means 57 stores a light emission current value which is to be a first setting light-receiving voltage, and compares a light-receiving voltage when the foam detection sensor 70 emits light at the light emission current value with a second setting light-receiving voltage larger than the first setting light-receiving voltage to detect the presence or absence of detergent foam, thereby allowing the detergent foam abnormally generated during washing to be detected, and the formation of the passage having a smooth inner wall without having a projection inside the hot air blowing passage 49 can prevent lint, foreign matters and the like from being attached thereto to prevent false detection caused by them.

Description

  The present invention relates to a washing machine having a clothes drying function.

  Conventionally, in this type of washing machine, in order to dry clothes, the warm air generated by the warm air generating means is sent from the air outlet provided in the water receiving tank through the warm air blowing path. A configuration has been proposed in which detergent bubbles that have entered the hot air blowing path during washing are detected by a pair of electrodes and are handled. (For example, refer to Patent Document 1).

  FIG. 9 shows a longitudinal sectional view of a conventional washing machine described in Patent Document 1. As shown in FIG.

  In FIG. 9, the rotating drum 131 for storing the laundry is rotatably disposed in the water receiving tank 133. A rotating shaft 134 is provided at the rotation center of the rotating drum 131, and a motor 135 is directly connected to the rotating shaft 134 to drive the rotating drum 131 to rotate. The water receiving tank 133 is elastically supported by the spring body 140 and the damper 141 from the washing machine body 139 so as to be swingable. One end of the drainage path 142 is connected to the lower part of the water receiving tank 133, and the other end of the drainage path 142 is connected to the water receiving tank 133. The washing water in the water receiving tank 133 is drained by connecting to a drain valve (not shown). The water supply valve 144 supplies water into the water receiving tank 133, and the water level detection means 146 detects the water level in the water receiving tank 133.

  The drying function includes a heater 147, a blower fan 148, and a hot air blowing path 149, and a hot air intake port 150 for taking in the air in the water receiving tank 133 is provided on the back of the upper surface of the water receiving tank 133. 151 is provided below the back surface of the water receiving tank 133, and the air in the water receiving tank 133 is heated and circulated in the direction of the solid arrow to dry the laundry. In addition, an overflow inlet 153 of the overflow drainage unit 152 is provided at the lower front part of the water receiving tank 133, and a pair of electrodes 154 are provided in the vicinity of the warm air blowing port 151 in the warm air blowing path 149. The lowest part of the overflow inlet 153 becomes the overflow surface 155, and the lowermost ends of the pair of electrodes 154 are at a position about 3 mm above the overflow surface 155.

  In the above configuration, when detergent bubbles are detected by a change in the resistance value between the electrodes during the washing process, the process proceeds to a process of eliminating the bubbles. This is a process in which the rotating drum 131 is rotated while draining to erase bubbles on the draft surface and the heater 147 and the blower fan 148 are operated to dry the surface while blowing bubbles to erase the bubbles. When the detergent foam is completely erased, the process returns to the washing process.

Japanese Patent Laying-Open No. 2005-143531

  However, in such a conventional washing machine, since the electrode for detecting detergent bubbles is provided in the hot air blowing path, the electrode is exposed to the air flowing out of the water receiving tank. At this time, since the air flowing out from the water receiving tub contains fine lint and lint generated from the laundry, it is inevitable that these foreign substances adhere to the electrodes.

  If lint or lint adheres between the electrodes, the lint or lint that adheres between the electrodes causes the resistance value between the electrodes to be less than that when the foam is not entering the hot air blowing path during the next wash. Because of the change, there was a problem of erroneously detecting that a bubble entered.

  The present invention solves the above-mentioned conventional problems, and by detecting detergent bubbles by transmitting light such as infrared rays, failure caused by adhesion of bubbles generated during washing to electrical parts, lint and foreign matter It is intended to prevent false detection due to adhesion of the like.

  In order to solve the above-described conventional problems, a washing machine of the present invention includes a rotating drum for storing laundry, a water receiving tub in which the rotating drum is rotatably included, and a motor that rotationally drives the rotating drum. A heater for drying the laundry in the rotating drum, a blower fan for circulating the drying air in the drying process, a hot air blowing path for circulating the drying air, and a lower rear side of the water receiving tub A bubble detection sensor that is formed in the hot air blowing path and is connected to the hot air blowing path, and is provided in the warm air blowing path in the vicinity of the hot air blowing opening and detects detergent bubbles that have entered the hot air blowing path. And a drain valve for draining water in the water receiving tank, and a control means for controlling each step of washing, rinsing, dehydration, drying, etc. by controlling the motor, heater, blower fan, drain valve, etc. Comprising the foam detection sensor A light emitting element and a light receiving element are arranged outside the air blowing path so as to be opposed to the axis center of the warm air blowing path at right angles, and the control means sets a light emitting current value to be a first set light receiving voltage. Storing and comparing the light reception voltage when the foam detection sensor emits light with the light emission current value and a second set light reception voltage larger than the first set light reception voltage to detect the presence or absence of detergent bubbles It is what.

  This prevents detergent bubbles that occur abnormally during washing from penetrating deep into the hot air blowing path and sticking to electrical components such as heaters and fans, resulting in corrosion or electrical shorts. Can do.

  And since it can be set as the path | route of a smooth inner wall, without having a processus | protrusion in a warm air ventilation path | route like an electrode, there is no adhesion of a waste thread, a foreign material, etc., and the misdetection by these can be prevented.

  The washing machine of the present invention detects bubbles by light transmission such as infrared rays, so that the detergent bubbles generated during washing adhere to the electrical part, and malfunctions due to adhesion of lint, foreign matter, etc. Prevention can be realized.

1 is a longitudinal sectional view of a washing machine according to Embodiments 1 and 2 of the present invention. Longitudinal sectional view of the washing machine different from FIG. Partial sectional view of foam detection sensor part of the washing machine Partially block circuit diagram of the washing machine Front view of input setting means and display means of the washing machine Operation flowchart of washing machine according to embodiment 1 of the present invention Initialization flowchart of washing machine according to embodiment 1 of the present invention Operation flowchart of washing machine according to embodiment 2 of the present invention Vertical section of a conventional washing machine

  According to a first aspect of the present invention, there is provided a rotary drum for storing laundry, a water receiving tub in which the rotary drum is rotatably included, a motor for rotationally driving the rotary drum, and drying the laundry in the rotary drum. A heater for circulating air, a blower fan for circulating the drying air in the drying process, a hot air blowing path for circulating the drying air, and a hot air blowing path formed below the back surface of the water receiving tank. A hot air blowing port, a bubble detection sensor that is provided in the hot air blowing path in the vicinity of the hot air blowing port and detects detergent bubbles that have entered the hot air blowing path, and water in the water receiving tank. A drain valve for draining, and a control means for controlling each step of washing, rinsing, dehydration, drying, etc. by controlling the motor, heater, blower fan, drain valve, etc. The warm air is blown outside the wind blowing path. The light-emitting element and the light-receiving element are arranged so as to face each other at right angles to the axis center of the road, the control means stores a light-emitting current value that is a first set light-receiving voltage, and the bubble detection sensor is the light-emitting current value. By comparing the light reception voltage when light is emitted with the second set light reception voltage, which is larger than the first set light reception voltage, to detect the presence or absence of detergent bubbles, abnormally occurred during washing Detergent bubbles can be detected, and it can be a smooth inner wall path without protrusions in the hot air blowing path, so there is no sticking of lint or foreign matter, etc., preventing false detection due to these Can do.

  In the second aspect of the invention, the control means resets and stores the light emission current value to be the first set light reception voltage at the end of the washing process when the foam detection sensor does not detect the detergent foam. By doing so, even if dirt or dust adheres to the inner and outer surfaces of the light emitting / receiving section and the transmissivity changes with time, it is automatically corrected during the process, so that bubbles can be detected reliably.

  In the third invention, when the control means detects the detergent foam by the foam detection sensor, the drain valve is operated to drain the water in the water receiving tank to a predetermined water level or all, and the heater and the blower fan are turned on. By operating continuously or intermittently during the operation of the drain valve and after the end of the operation, the detergent bubbles can be quickly removed from the tank or the hot air blowing path.

  In the fourth invention, since the light emitting element and the light receiving element of the bubble detection sensor have either the infrared wavelength region or the wavelength region of the visible light wavelength region as the main detection wavelength, a cheaper bubble detection sensor is realized. be able to.

  Hereinafter, embodiments of the invention will be described with reference to the drawings. Further, the present invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a washing machine according to Embodiment 1 of the present invention, and FIG. 2 is a longitudinal sectional view showing a configuration of a drying function in a section different from FIG.

  In FIG. 1, a rotating drum 31 is formed in a bottomed cylindrical shape, and a large number of water passage holes 32 are provided on the entire surface of the rotating drum 31, and are rotatably disposed in a water receiving tank 33. A rotation axis (rotation center axis) 34 is provided in the inclination direction at the rotation center of the rotary drum 31, and the axial center direction of the rotation drum 31 is inclined downward from the front side toward the back side. A motor 35 attached to the rear surface of the water receiving tank 33 is connected to the rotating shaft 34, and the rotating drum 31 is rotated in the forward and reverse directions. A plurality of protruding plates 36 for stirring clothes are provided on the inner wall surface of the rotating drum 31. Then, the opening provided on the upward inclined surface on the front side of the water receiving tub 33 is covered with a lid 37 so that it can be opened and closed. By opening the lid 37, the laundry can be taken in and out of the rotary drum 31 through the clothing doorway 38. I am doing so. Since the lid body 37 is provided on the upward inclined surface, the laundry can be carried out without bending the waist.

  The water receiving tub 33 is elastically supported by the spring body 40 and the damper 41 from the washing machine main body 39 so as to be swingable. One end of the drainage path 42 is connected to the lower part of the water receiving tub 33, The other end is connected to the drain valve 43 so that the washing water in the water receiving tank 33 can be drained in a timely manner. The water supply valve (water supply means) 44 supplies water into the water receiving tank 33 through the water supply path 45, and the water level detection means 46 detects the water level in the water receiving tank 33. In addition, a control device 56 is disposed in the lower part of the front surface in the washing machine main body 39.

  In the first embodiment, the rotation shaft 34 is provided at the rotation center of the rotary drum 31 in the inclination direction, and the axial center direction of the rotation drum 31 is inclined downward from the front side toward the back side. However, the rotating shaft 34 may be provided in the horizontal direction at the rotation center of the rotating drum 31, and the axial center direction of the rotating drum 31 may be disposed in the horizontal direction.

  In FIG. 2, as a drying function, a heater 47, a blower fan 48, and a hot air blowing path 49 are provided, and communicate with the warm air blowing path 49 to supply hot air intake 50 for taking in air in the water receiving tank 33. By providing the hot air blowing port 51 below the back of the water receiving tank 33, the air in the water receiving tank 33 is heated and circulated in the direction of the solid line arrow to dry the laundry. I am letting.

  Further, an overflow inlet 53 of the overflow drainage 52 is provided in front of the lower surface of the water receiving tank 33, and a bubble detection sensor 70, which will be described later with reference to FIG. Is provided. And the lowest part of this overflow inflow port 53 becomes the overflow surface 55, and the optical axis (it mentions later in FIG. 3) of the bubble detection sensor 70 exists in the position about 25 mm above this overflow surface 55.

  FIG. 3 is a partial cross-sectional view of the foam detection sensor unit of the washing machine according to Embodiment 1 of the present invention.

  In FIG. 3, the foam detection sensor 70 is configured so that the detergent foam generated in the rotating drum 31 during the laundry stirring operation is generated in the hot air blowing path 49 from the hot air blowing port 51 provided below the back surface of the water receiving tank 33. , And comprises a light-emitting element 70b such as an infrared light-emitting diode and a light-receiving element 70a such as an infrared phototransistor. The above-described optical axis is perpendicular to the axial center of the hot air blowing path 49. The light emitting element 70b and the light receiving element 70a are arranged facing each other.

  The hot air blowing path 49 is formed of a material having transparency to the effective wavelengths of the light emitting element 70b and the light receiving element 70a around the optical axis, and by forming the thin portions 77a and 77b in the light receiving and emitting parts. Further, the permeability is increased. In normal operation, the inside of the hot air blowing path 49 between the light emitting element 70b and the light receiving element 70a is air, and the light transmittance is good. When the detergent bubbles enter here, the light is refracted and reflected by the bubbles and the permeability is lowered. For this reason, the output voltage of the light receiving element 70a decreases when the light emission amount of the light emitting element 70b is constant compared to the case of normal air. Thereby, the presence or absence of bubbles can be detected.

  The effective wavelengths of the light emitting element 70b and the light receiving element 70a are not limited to the infrared region, and may be detected in the visible light region. In that case, the hot air blowing path 49 is made of a material having transparency to the visible light region which is the effective wavelength of the light emitting element 70b and the light receiving element 70a around the optical axis. Furthermore, when the sensitivity of the light emitting element 70b and the light receiving element 70a is high, the opposing arrangement is not limited to the optical axis, and the optical axes of the light emitting element 70b and the light receiving element 70a may be shifted within a range in which the presence or absence of bubbles can be detected. . If the light emitting element 70b and the light receiving element 70a have the visible light region as the main detection wavelength, the cost of the bubble detection sensor 70 can be reduced. Further, if there is an allowable width for the deviation of the optical axis, it is not necessary to strictly manage the optical axis variation in manufacturing, and the productivity can be improved.

  FIG. 4 is a partial block diagram of the washing machine according to Embodiment 1 of the present invention.

  4, the control device 56 is configured as shown in the figure, and controls the operation of the motor 35, the drain valve 43, the water supply valve 44, the blower fan 48, the heater 47, and the like to wash, rinse, dehydrate, and dry. And a control means 57 comprising a microcomputer for sequentially controlling a series of processes.

  The control means 57 inputs information from the input setting means 58 for setting the driving course, etc., displays the information on the display means 59 based on the information, notifies the user, and starts the operation by the input setting means 58. Is set, the data from the water level detecting means 46 for detecting the water level in the water receiving tank 33 is input and the drain valve 43, the water supply valve 44, the blower fan 48, and the heater 47 are input via the load driving means 60. Control the operation of the washing, drying operation.

  At this time, the control means 57 controls the rotation of the motor 35 by controlling the inverter circuit 63 via the drive circuit 62 based on the information from the position detection means 61 that detects the position of the rotor of the motor 35. I have to. Although the motor 35 is a direct current brushless motor, although not shown, the motor 35 is composed of a stator having a three-phase winding and a rotor having a two-pole permanent magnet disposed on the ring. The stator has a three-phase winding. The first winding 35a, the second winding 35b, and the third winding 35c to be configured are wound around an iron core provided with a slot.

  The inverter circuit 63 is composed of a switching element composed of a parallel circuit of a power transistor (IGBT) and a reverse conducting diode. A series circuit of a first switching element 63a and a second switching element 63b, a series circuit of a third switching element 63c and a fourth switching element 63d, and a fifth switching element 63e and a sixth switching element 63f A series circuit is configured, and the series circuit of each switching element is connected in parallel.

  Here, both ends of the series circuit of the switching elements are input terminals, connected to a DC power source, and output terminals are respectively connected to connection points of two switching elements constituting the series circuit of the switching elements. The output terminal is connected to the U terminal, V terminal, and W terminal of the three-phase winding, and the U terminal, V terminal, and W terminal are connected by the on / off combination of two switching elements constituting the series circuit of the switching element. The three states are positive voltage, zero voltage, and release, respectively.

  The on / off of the switching element is controlled by the control means 57 based on information from the three position detection means 61a, 61b, 61c comprising Hall ICs. The position detection means 61a, 61b, 61c are arranged on the stator so as to face the permanent magnets of the rotor at an electrical angle of 120 degrees.

  During one rotation of the rotor, the three position detectors 61a, 61b, 61c each output a pulse at an electrical angle of 120 degrees. The control means 57 detects when the signal state of any of the three position detection means 61a, 61b, 61c changes, and based on the signals of the position detection means 61a, 61b, 61c, the switching elements 63a-63f. By changing the on / off state, the U terminal, the V terminal, and the W terminal are brought into three states of positive voltage, zero voltage, and release, and the first winding 35a, the second winding 35b, and the third winding of the stator. The coil 35c is energized to generate a magnetic field, and the rotor is rotated.

  The switching elements 63a, 63c, and 63e are each controlled by pulse width modulation (PWM), for example, by controlling the energization ratio of high and low at a repetition frequency of 10 kHz to control the rotational speed of the rotor. The control means 57 detects the cycle every time the signal state of any of the three position detection means 61a, 61b, 61c changes, calculates the rotational speed of the rotor from that period, and sets it to the set rotational speed. The switching elements 63a, 63c, and 63e are PWM-controlled.

  The current detection means 64 includes a resistor 65 connected to one input terminal of the inverter circuit 63 and a current detection circuit 66 connected to the resistor 65, detects the input current value of the inverter circuit 63, and outputs the output. This is input to the control means 57. When the motor 35 is a direct current brushless motor, the torque is substantially proportional to the input current. Therefore, the torque of the motor 35 is detected by detecting the input current value of the inverter circuit 63 by the current detection circuit 66 connected to the resistor 65. can do.

  The cloth amount detection means 67 detects the amount of laundry in the rotary drum 31, and based on a signal from the current detection circuit 64 when the rotary drum 31 is raised to a predetermined rotation speed (for example, 200 r / min), The amount of laundry in the rotary drum 31 is detected.

  The commercial power supply 24 is connected to the inverter circuit 63 via a DC power supply conversion device including a diode bridge 68, a choke coil 69, and a smoothing capacitor 76. However, this is only an example, and the configuration of the motor 35, the configuration of the inverter circuit 63, and the like are not limited thereto.

  As described above, the bubble detection sensor 70 opposes the light emitting element 70b such as an infrared light emitting diode and the light receiving element 70a such as an infrared phototransistor on the optical axis perpendicular to the axial center of the hot air blowing path 49. Deploy. In normal operation, the inside of the hot air blowing path 49 between the light emitting element 70b and the light receiving element 70a is air, and the light transmittance is good. When bubbles enter here, light is refracted and reflected by the bubbles, and the transmittance is lowered. For this reason, the output voltage of the light receiving element 70a is lowered when the light emission amount of the light emitting element 70b is constant compared to the case of normal air. Thus, the presence or absence of bubbles can be detected by the bubble detection means 71.

  The light emission amount of the light emitting element 70 b is set by the pulse width modulation (PWM) of the control means 57 via the current adjustment circuit 72. For example, a pulse waveform with high and low energization ratios determined at a repetition frequency of 10 kHz is smoothed by the current adjustment circuit 72 and converted to direct current so that the light emitting element 70b emits light at a constant level. At this time, the driving of the light emitting element 70b may be pulse driving in which the peak value is constant at a set value. Since the internal resistance of the light receiving element 70a changes according to the degree of transmission of the hot air blowing path 49, it can be obtained as a voltage change by dividing the internal resistance with the control means 57. That is, when this built-in resistor is connected in series with the power supply voltage + side of the control means 57 so that the light receiving element 70a is on the power supply voltage reference (0V) side, the internal resistance of the light receiving element 70a is small when the transmittance is high. Since the internal resistance of the light receiving element 70a is large when the transmittance is low, the voltage across the light receiving element 70a increases. The storage unit 74 stores a pulse width modulation (PWM) energization ratio for setting the light emission amount of the light emitting element 70b, and reads and writes data from the control unit 57 as necessary.

  FIG. 5 is a front view of input setting means and display means of the washing machine according to Embodiment 1 of the present invention.

  In FIG. 5, the input setting means 58 includes a washing time setting switch 58a for setting a washing time, a rinsing frequency setting switch 58b for setting the number of rinsings, a dehydration time setting switch 58c for setting the dehydration time, and a drying time for setting the drying time. A setting switch 58d, a start / pause switch 58e, a power-on switch 58f, a power-off switch 58g, and the like are included. In addition, a first course setting switch 58h and a second course setting switch 58i are provided, and a drying setting switch 58j is further provided.

  The first course setting switch 58h is used to set the course to be operated. A course for performing a series of steps of washing, rinsing, dehydrating and drying, a course for performing each step of washing, rinsing and dehydration, and a drying step only. The course to be performed can be switched and set in the above order each time it is turned on.

  The second course setting switch 58i is used to switch between an automatic course, a rush course, a private course, a blanket course, a one-hour washing / drying course, and the like so that it can be switched in the above order each time it is turned on. Yes. The drying setting switch 58j is for setting a soft keep course in the drying process.

  The display means 59 includes a washing time display section 59a, a rinse count display section 59b, a dehydration time display section 59c, a drying time display section 59d, and a course setting display section 59e that displays the course set by the second course setting switch 58i. Etc. Further, it has a detergent amount display part 59f, a remaining time display part 59g, and a number display part 59h.

  About the washing machine comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  FIG. 6 is an operation flowchart of the washing machine according to the first embodiment of the present invention, and shows the operation when detergent bubbles are detected by the bubble detection sensor 70 during washing.

  Water is supplied and washing and stirring is started (step 101). In step 102, the foam detection flag Fb for temporarily storing the presence / absence of detection of detergent foam is set to 0, and the foam detection is temporarily disabled. In step 103, based on the PWM energization ratio stored in the storage unit 74, the light emitting element 70 b is caused to emit constant light and a light emission current value serving as a first set voltage is set. Next, in step 104, the voltage Vo between both ends of the light receiving element 70a for constant light emission of the light emitting element 70b is compared with the second set light receiving voltage Vs. If Vo> Vs is not satisfied (No in step 104), the presence of bubbles is present. It is determined that there is no washing, and the washing operation is continued. In step 105, the washing operation is terminated, and the process is normally completed (step 106). For example, if the power supply voltage of the control means is set to 5V, the second set light reception voltage Vs is set according to the transmittance due to actual bubbles, such as Vs = 3V. In step 104, if Vo> Vs (Yes in step 104), it is determined that bubbles have entered the hot air blowing path 49 from the hot air blowing port 51, and an abnormality processing sequence for erasing the bubbles is determined. to go into.

  In the abnormality processing sequence, first, the drain valve 43 is driven to start draining (step 107), and the rotating drum 31 is rotated (step 108) to promote the elimination of bubbles on the draft surface. Next, in step 109, the heater 47 and the blower fan 48 are operated to dry the surface while blowing the bubbles in the hot air blowing path 49 toward the water receiving tank 33, thereby eliminating the bubbles. When the water in the water receiving tank 33 is gradually removed and drainage is completed to a predetermined water level (step 110), the operations of the rotary drum 31, the heater 47, and the blower fan 48 are finished (step 111), and the bubble erasing process is performed. And the water is supplied to the previous water level and agitated (step 112).

  Thereafter, in step 113, the voltage Vo across the light receiving element 70a is measured again. If Vo> Vs is not satisfied (No in step 113), it is determined that there is no bubble and the erasure of the bubble is completed. Return to operation. In step 113, Vo> Vs (Yes in step 113), it is determined that the bubble has not been erased yet, and in step 114, the bubble erasing process has not been performed a predetermined N times (No in step 114). If it is determined, the bubble erasure processing operation from the start of drainage in step 107 to the water supply in step 112 is repeated, and if the bubble erasure is not performed even after performing N times a predetermined number of times in step 114 (Yes in step 114), the water receiving tank 33, draining water (step 115), setting the bubble detection flag Fb for temporarily storing the presence / absence of bubble detection to 1 (step 116), determining that further bubble erasure processing is impossible, The display is displayed as “U17” on the number display portion 59h of the display means 59 (step 117) to inform the user, and the process ends in this state (step 11). ).

  In addition, in the operation of the heater 47 and the blower fan 48 in step 109, it is possible to eliminate bubbles or dry the surface even if both the heater 47 and the blower fan 48 are operated or only the heater is intermittently operated. Power consumption can be reduced by performing intermittently. Further, if the heater 47 and the blower fan 48 are operated for a certain period of time after draining to the predetermined water level in step 110, it is possible to obtain a further bubble erasing effect.

  FIG. 7 is an initialization flowchart of the washing machine according to the first embodiment of the present invention, and shows the setting of the initial value for causing the light emitting element 70b to emit constant light.

  In FIG. 7, in step 201, the light emitting element 70b is caused to emit constant light with a PWM energization ratio corresponding to, for example, 10 mA. This value is arbitrarily determined depending on the performance of the light emitting element 70b and the like and does not need to be 10 mA, but is a value lower than the set value that will be stored after these processes. In step 202, the voltage Vo across the light receiving element 70a for the constant light emission of the light emitting element 70b is compared with the first set light receiving voltage 1.0 ± 0.1V. This value is arbitrarily determined depending on the performance of the light receiving element 70a, the degree of transmission of the hot air blowing path 49, etc., and need not be 1.0 ± 0.1 V, but the voltage across the light receiving element 70a when there is a bubble A lower value that can be distinguished from Vo. When Vo> 1.0 ± 0.1 V, the light emission current is small, so the PWM energization ratio is increased and the light emission current of the light emitting element 70b is added (step 203). If Vo = 1.0 ± 0.1V, it is determined that the initial setting is completed, and the PWM energization ratio at that time is stored in the storage means 74 (step 204).

  This operation may be performed before the washing machine is shipped from the factory, but may be automatically performed every time the washing process starts.

  As described above, the bubble detection sensor 70 includes the light emitting element 70b and the light receiving element 70a that are disposed outside the hot air blowing path 49 and opposed to the axial center of the hot air blowing path 49 at right angles. 57 stores the light emission current value that is the first set light reception voltage, the light reception voltage when the bubble detection sensor 70 emits light at the light emission current value, and the second set light reception voltage that is greater than the first set light reception voltage, , And by detecting the presence or absence of detergent bubbles, it is possible to detect the detergent bubbles that occur abnormally during washing, and the smooth inner wall has no protrusions in the hot air blowing path 49. Since it can be a route, there is no adhesion of lint, foreign matter, etc., and erroneous detection due to these can be prevented.

  Further, when detergent foam is detected by the foam detection sensor 70, the drain valve 43 is operated to drain the water in the water receiving tank 33 to a predetermined level or all, and the heater 47 and the blower fan 48 are connected to the drain valve. By operating continuously or intermittently during and after the operation, the detergent foam can be quickly removed from the tank or the hot air blowing path.

  Moreover, since the light emitting element 70b and the light receiving element 70a of the bubble detection sensor 70 have either the infrared wavelength region or the wavelength region of the visible light wavelength region as the main detection wavelength, a cheaper bubble detection sensor can be realized. Can do.

(Embodiment 2)
FIG. 8 is an operation flowchart of the washing machine according to the second embodiment of the present invention, and shows a process of correcting the secular change of the foam detection accuracy during washing.

  In FIG. 8, Step 101 to Step 104, Step 105 to Step 106, and Step 107 to Step 118 are the same as those in the first embodiment shown in FIG.

  Immediately before the end of the washing operation, if the bubble detection flag Fb is 1 in step 301, bubbles are still present, and the aging change in the bubble detection accuracy may not be corrected correctly, so correction is not performed (step 306). In step 105, the washing operation is terminated and the process is terminated (step 106).

  In step 301, if the bubble detection flag Fb is not 1, there is no bubble, so the sequence for aging correction is entered. In step 302, the light emitting element 70b emits light with a light emission current value corresponding to the PWM energization ratio stored in the storage means 74. In step 303, the voltage Vo across the light receiving element 70a with respect to the constant light emission of the light emitting element 70b is compared with the first set light receiving voltage 1.0 ± 0.1V. Here, if there is no dirt on the inner surface of the hot air blowing path 49 and the transmittance does not change, Vo = 1.0 ± 0.1 V (Yes in step 303), it is determined that the setting is completed, and the PWM at that time The energization ratio is stored in the storage means 74 (step 305), and the aging correction process is terminated.

  On the other hand, when the permeability is reduced due to adhesion of dirt on the inner surface of the hot air blowing path 49, Vo becomes higher than 1.0 ± 0.1V. When the voltage is higher than 1.0 ± 0.1 V (No in step 303), the next detection accuracy can be improved by performing correction by increasing the light emission current value. That is, in step 304, the PWM energization ratio is increased and the light emission current of the light emitting element 70b is added so that Vo = 1.0 ± 0.1V. Then, a new PWM energization ratio when this is satisfied is stored in the storage means 74 (step 305), and the aging correction process is terminated.

  Although this operation has been described in the case where it is performed immediately before the end of the washing operation, the value of the foam detection flag Fb is stored in the storage means 74, and the previous value of the foam detection flag Fb is stored from the storage means 74 at the start of the next washing. May be read out and corrected after the determination.

  As described above, at the end of the washing process when the detergent detection bubble is not detected by the foam detection sensor, the light emission current value that is the first set light reception voltage is reset and stored again. Even if dirt or dust adheres to the inner and outer surfaces of the air blowing path 49 and the transmittance changes over time, the correction is automatically made in the process, so that bubbles can be detected reliably.

  As described above, the washing machine according to the present invention detects the detergent bubbles with the light emitting element and the light receiving element arranged opposite to the outside of the hot air blowing path, and performs the defoaming operation to thereby electrically Since the parts can be protected, the present invention can be applied to devices using various detergents, for example, washing machines.

DESCRIPTION OF SYMBOLS 31 Rotating drum 33 Water receiving tank 35 Motor 43 Drain valve 47 Heater 48 Blower fan 49 Hot air blowing path 51 Hot air blowing port 57 Control means 70 Bubble detection sensor 70a Light receiving element 70b Light emitting element

Claims (4)

A rotating drum for storing laundry; a water receiving tub that rotatably includes the rotating drum; a motor that rotationally drives the rotating drum; and a heater for drying the laundry in the rotating drum; A blower fan that circulates the drying air in the drying process, a hot air blowing path for circulating the drying air, and a hot air blowing port that is formed below the back surface of the water receiving tank and communicates with the warm air blowing path; A foam detection sensor that is provided in the hot air blowing path near the hot air blowing port, detects a detergent foam that has entered the hot air blowing path, and a drain valve that drains the water in the water receiving tank, Control means for controlling each step of washing, rinsing, dehydration, drying, etc. by controlling the motor, heater, blower fan, drain valve, etc., the foam detection sensor is located outside the hot air blowing path And the axis of the hot air blowing path The light-emitting element and the light-receiving element are arranged to face each other, and the control unit stores a light-emitting current value that is a first set light-receiving voltage, and the bubble detection sensor emits light at the light-emitting current value. A washing machine that detects the presence or absence of detergent bubbles by comparing a light reception voltage with a second set light reception voltage that is higher than the first set light reception voltage. 2. The control means according to claim 1, wherein at the end of the washing process when no detergent foam is detected by the foam detection sensor, the light emission current value to be the first set light reception voltage is reset and stored again. Washing machine. When the foam detection sensor detects the detergent foam, the control means operates the drain valve to drain the water in the water receiving tank to a predetermined water level or all, and the heater and the blower fan are operating the drain valve. The washing machine according to claim 1, wherein the washing machine is operated continuously or intermittently after the operation ends. The washing machine according to any one of claims 1 to 3, wherein the light-emitting element and the light-receiving element of the foam detection sensor have an infrared wavelength region or a wavelength region of a visible light wavelength region as a main detection wavelength.

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