JP2009273488A - Washing/drying machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize the whole of a washing/drying machine and to reduce its weight while suppressing the decline of the performance of a heat pump and preventing the malfunction of a compressor, the washing/drying machine being provided with a drying function by the heat pump. <P>SOLUTION: In a drying process, by driving a circulating fan 30 and the compressor 34, air inside a water tub 3 is circulated through an evaporator 32 and a condenser 33 inside a ventilation duct 26 in the order, to become hot air and is supplied into the water tub 3, and laundry is dried. A controller for operation-controlling the operation frequency of the inverter of the compressor 34 at a variable speed executes the control of operating the compressor 34 at ≤ a prescribed rotation number Rt (85 Hz) lower than the target maximum frequency Rmax (100 Hz) after the lapse of prescribed time T (30 minutes) from the start of the drying process. Thus, the outflow of oil from the compressor 34 is suppressed and a preferable oil surface height is maintained at all times. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a washing dryer having a drying function using a heat pump.

  For example, in household laundry dryers, in recent years, laundry dryers that perform a drying operation using a heat pump have been provided instead of those that perform a drying operation using a conventional drying heater (for example, Patent Document 1). This washing / drying machine has a heat pump (refrigeration cycle) in which a compressor, a condenser, a capillary tube, and an evaporator are connected in a closed loop by a refrigerant pipe, and the air in the washing tub is passed through the evaporator and the condenser in order. And a circulation circulation passage for drying to be returned to the washing tub. In this circulation circulation passage for drying, air (warm air) heated by a condenser is supplied into the washing tub and dehydrates the laundry, then cooled and dehumidified by an evaporator, and heated again by a condenser. Such a circulation is to be performed. Drying using this heat pump has advantages such as better energy efficiency and less wrinkles and shrinkage than drying using a heater.

  The control device for the washing and drying machine is configured to drive the motor of the compressor at a variable speed by, for example, inverter control (control of operating frequency). In this case, conventionally, at the start of operation of the compressor, as shown in FIG. 9, for example, the frequency is increased to 60 Hz over 1 Hz per second, that is, 1 minute (60 seconds), and the frequency 60 Hz is increased to 1 The control was performed such that the frequency was maintained for 1 minute and then increased by 1 Hz per second until the target maximum frequency (for example, 100 Hz) was reached. After the operating frequency of the compressor reaches the target maximum frequency, the upper limit of the temperature is detected based on the detection of the discharge temperature sensor that detects the discharge temperature of the compressor and the condenser temperature sensor that detects the outlet temperature of the condenser. Is detected, control is performed such that the operating frequency of the compressor is lowered by a certain value (5 Hz).

The heat pump compressor mechanism (the sliding part of the metal member) is lubricated in a state where it is immersed in the refrigeration oil. The refrigeration oil dissolves in the refrigerant. Easy compatible oils are generally employed. In this case, the refrigeration oil is circulated through the refrigerant pipe together with the refrigerant in a state of being mixed in the refrigerant. Further, as the compressor, one having an accumulator at the inlet is used, and by this accumulator, refrigerant (and refrigerating machine oil) can be buffered and temporarily stored, gas-liquid separation, foreign matter removal, etc. Yes.
JP 2006-87484 A

  By the way, since the above-mentioned washing / drying machine has a built-in heat pump, it causes an increase in size and weight in the height direction. Therefore, in a washing and drying machine equipped with this type of heat pump, while maintaining the performance as a heat pump, in particular, the compressor (accumulator) of the devices constituting the heat pump should be reduced in size and weight. Has been requested.

  Therefore, the present inventor, in the washing and drying machine provided with the above-described heat pump, firstly downsizes the frame (case) of the compressor in the height direction and secondly reduces the volume of the accumulator. Tried. However, it has been clarified that the following problems occur when the compressor frame and accumulator are downsized in order.

  That is, in a heat pump, if the amount of refrigeration oil enclosed is sufficient, the amount of oil flowing out of the compressor and the amount of oil returned to the compressor during the drying process (when the compressor is operating) are balanced. However, no trouble occurs in the operation of the compressor. However, when the first compressor frame is downsized, the amount of refrigeration oil enclosed decreases as a whole, and therefore, when a predetermined time (for example, 30 minutes) elapses from the start of the drying process, It happens that the amount of oil flowing out is greater than the amount flowing in. For this reason, the required oil level in the compressor cannot be ensured, and as a result, there arises a problem that the operation of the compressor is hindered.

  Further, in the heat pump, there is a circumstance that the refrigerant and oil remaining in the condenser and the evaporator are suddenly returned to the compressor side, particularly at the start of the drying process (at the start of operation of the compressor). . Second, when the accumulator is downsized, the liquid storage capacity is reduced, so that the return amount of the liquid refrigerant and oil increases at the start of the drying process (at the start of compressor operation), and is stored in the accumulator. The liquid refrigerant is sucked into the compressor without being exhausted, and as a result, the operation of the compressor may be hindered.

  The present invention has been made in view of the circumstances described above, and its purpose is to have a drying function by a heat pump, while suppressing deterioration of the performance of the heat pump and preventing malfunction of the compressor. An object of the present invention is to provide a washing / drying machine capable of reducing the overall size and weight.

  According to the test and research of the present inventor, when the compressor frame is downsized in the height direction and the amount of refrigeration oil is reduced, the rotational speed of the compressor after a certain time has elapsed since the start of the drying process. If it remains relatively high (the number of revolutions close to the target maximum number of revolutions), the amount of oil that flows out of the compressor may be greater than the amount that flows in, and the required oil level in the compressor This causes a problem that cannot be secured.

  A first washing / drying machine of the present invention includes a washing tub in which laundry is accommodated, a heat pump in which a compressor, a condenser, a decompression unit, an evaporator, and an accumulator are connected in a closed loop shape by a refrigerant pipe, An air circulation mechanism that circulates the air in the washing tub through the evaporator and the condenser in order and returns the air to the washing tub when performing a stroke; and a compressor that controls the operation of the compressor at a variable speed And a compressor control unit that controls the compressor to operate at a predetermined rotation speed lower than a target maximum rotation speed after a predetermined time has elapsed from the start of the drying process. However, it has characteristics.

  Further, according to the test and research by the present inventor, when the accumulator is downsized and the liquid storage capacity is reduced, the degree of increase in the rotational speed of the compressor at the start of the drying process (for example, about 4 minutes from the start of operation). It was confirmed that the return amount of the liquid refrigerant and oil increases to a level that cannot be accommodated by the accumulator.

  A second washing / drying machine of the present invention includes a washing tub in which laundry is stored, a compressor, a condenser, a decompression means, an evaporator, an accumulator connected in a closed loop by a refrigerant line, and a drying machine. An air circulation mechanism that circulates the air in the washing tub through the evaporator and the condenser in order and returns the air to the washing tub when performing a stroke; and a compressor that controls the operation of the compressor at a variable speed And at the beginning of the drying process, the compressor control means sets the rotation speed of the compressor to a moderate increase degree compared to the increase degree of the normal rotation speed. It is characterized in that control is performed to increase the target maximum rotational speed.

  According to the first washing / drying machine of the present invention, which has a drying function by a heat pump, the compressor is controlled at a target maximum rotational speed after a predetermined time has elapsed from the start of the drying process. Even if the compressor frame is downsized in the height direction and the amount of refrigeration oil is reduced, the compressor flows out from the compressor. The amount of oil and the amount of oil flowing in can be equalized, and the required oil level in the compressor can be maintained. As a result, the performance of the heat pump can be suppressed and the compressor can be downsized in the height direction while preventing the compressor from malfunctioning. As a result, the overall size and weight can be reduced. .

  According to the second washing / drying machine of the present invention, which has a drying function by a heat pump, the compressor control means sets the rotation speed of the compressor at the initial stage of the drying process to the normal rotation speed. Since the control is made to increase toward the target maximum rotational speed so that the degree of increase is more gradual than the degree of increase, the accumulator is downsized and the liquid storage capacity is reduced. Even in this case, the degree of increase in the rotational speed of the compressor at the start of the drying process can be made relatively small, and the return amount of the liquid refrigerant and oil can be suppressed to a level that can be accommodated by the accumulator. As a result, the accumulator can be reduced in size while suppressing the deterioration of the performance of the heat pump and preventing malfunction of the compressor, and as a result, the overall size and weight can be reduced.

(1) First Example Hereinafter, a first example in which the present invention is applied to a drum-type washing / drying machine will be described with reference to FIGS. FIG. 1 schematically shows the overall configuration of a drum-type washing / drying machine 1 according to this embodiment. Here, inside the outer box 2 of the washing / drying machine 1, a cylindrical water tank 3 is supported via an elastic support mechanism 4 (only a part of which is shown) in a state where the water tank 3 is inclined rearwardly.

  A cylindrical rotating tank (drum) 5 is rotatably supported in the water tank 3. The rotating tank 5 is configured to rotate around an inclined axis that extends in the front-rear direction and is inclined rearwardly downward. An opening 6 through which laundry is taken in and out is provided on the front surface of the rotating tub 5. A number of holes 7 (only part of which are shown) are formed in the peripheral wall portion of the rotating tub 5, and a plurality of baffles for stirring the laundry are formed on the inner surface of the peripheral wall portion of the rotating tub 5. 8 is provided. The rotating tub 5 functions as a washing tub, a dewatering tub, and a drying tub in which laundry is stored.

  On the front surface (the left surface in FIG. 1) of the water tub 3, an input port 9 for taking in and out the laundry is formed so as to surround the opening 6 of the rotating tub 5. An opening 10 corresponding to the charging port 9 is provided on the front surface of the outer box 2, and the charging port 9 and the opening 10 are water-tightly connected by a bellows 11. And the door 12 which opens and closes the opening part 10 (input port 9) is provided in the front surface of the outer box 2. As shown in FIG.

  A motor 13 made of, for example, an outer rotor type brushless motor is disposed at the rear of the water tank 3. The tip of the rotating shaft 13 a of the motor 13 penetrates the back surface of the water tank 3 and protrudes into the water tank 3, and is connected and fixed to the rear part of the rotating tank 5. With such a configuration, the rotating tub 5 is directly driven to rotate by the motor 13.

  A water pouring case 14 is provided on the ceiling of the outer box 2 so as to be located above the water tank 3. The water injection case 14 includes a detergent charging unit and a softening agent charging unit (not shown), and is connected to the water tank 3 via a water injection hose 15. A water supply valve 16 including an electromagnetic switching valve for supplying water from a water supply source (water supply in this case) into the water tank 3 is provided behind the water injection case 14.

  Although not shown in detail, the water supply valve 16 has one inlet port connected to the water supply and two switchable outlet ports, one of which is the water injection case through the water supply pipe. 14 to supply water into the water tank 3 through the water injection case 14. On the other hand, the other outlet port of the water supply valve 16 is connected to the water supply hose 17. The water supply hose 17 is provided so that water from a water supply source can be supplied into the water tank 3 after heat exchange (heating) is performed in a condenser portion described later.

  In addition, a drain port 18 is provided in the lower part of the water tank 3. A drain pipe 19 is connected to the drain port 18, and a drain valve 20 is provided in the middle of the drain pipe 19. The drain pipe 19 extends to the outside of the outer box 2 so that water in the water tank 3 is drained to a predetermined drainage place such as a washroom. Although not shown in detail, an air trap (not shown) communicating with the inside of the water tank 3 is provided at the lower rear surface of the water tank 3, and this air trap is placed in the outer box 2 via an air tube (not shown). Is connected to a water level sensor 21 (shown only in FIG. 4).

  An air supply port 22 and an exhaust port 23 are provided at the upper rear surface and upper front surface of the water tank 3, respectively. At this time, a plurality of vent holes 24 are provided on the rear wall portion of the rotating tub 5 in an annular shape corresponding to the air supply ports 22. In this case, since the air supply port 22 and the exhaust port 23 are located in the upper part of the water tank 3, washing water or the like does not enter the circulation ventilation path described below.

  As shown in FIG. 2, both ends of a circulation ventilation path constituting the air circulation mechanism 25 are connected to the air supply port 22 and the exhaust port 23 outside the water tank 3. The circulation ventilation path includes a ventilation duct 26 positioned below the water tank 3, an air supply duct 27 positioned at the rear of the water tank 3 and connecting the rear end of the ventilation duct 26 and the air inlet 22, and the front of the water tank 3. And an exhaust duct 28 connecting the exhaust port 23 and the front end of the ventilation duct 26.

  A circulation fan 30 driven by a fan motor 29 is provided at a rear portion in the ventilation duct 26. An evaporator (evaporator) 32 and a condenser (condenser) 33 constituting a heat pump 31 (described later) are arranged in this order from the front in the ventilation duct 26 upstream of the circulation fan 30. The evaporator 32 and the condenser 33 each have a well-known configuration in which refrigerant pipes are arranged in a meandering manner between the left and right heat transfer fins, and heat exchange is performed by the passage of air between the heat transfer fins. Is supposed to do.

  As a result, the circulation fan 30 is driven to rotate, so that the air in the water tank 3 (rotating tank 5) passes through the exhaust duct 28 from the exhaust port 23 as shown by arrows in FIGS. Then, the air reaches the ventilation duct 26, passes through the evaporator 32 and the condenser 33 in order, flows to the air supply duct 27, and is supplied to the rotary tank 5 through the air supply port 22 and the air vent 24. It has come to be.

  Here, the heat pump (refrigeration cycle) 31 will be described. As shown in FIG. 2, the heat pump (refrigeration cycle) 31 is a compressor (compressor) 34 disposed at the bottom front (see FIG. 1) in the outer box 2, the condenser 33, and a decompression means. The expansion valve 35, the evaporator 32, and the accumulator 36 are configured to be connected in a closed loop by a refrigerant pipe (pipe) 37. A heat pump (refrigeration cycle) 31 is filled with a required amount of refrigerant and refrigerator oil for lubricating the compressor 34. The refrigerating machine oil is circulated through the refrigerant pipe 37 together with the refrigerant while being mixed in the refrigerant.

  Among them, as schematically shown in FIG. 3, the compressor 34 has a compression mechanism 39 that is driven by a motor 38 and its rotating shaft 38a in a frame (case) 34a, and sucks it from an inlet 34b. The gas refrigerant is compressed to a high temperature and a high pressure and discharged from the outlet 34c. The compression mechanism 39 is lubricated in a state where it is immersed in refrigeration oil. Here, the height of the oil surface in the frame 34a is the minimum required reference height indicated by a broken line in FIG. It is desirable that the height is H or more, preferably 1.5 mm or more higher than the minimum reference height H. In this embodiment, the height of the compressor 34 is reduced to about 170 mm from the conventional 235 mm. Along with this, the amount of oil enclosed has also been reduced from the conventional 370 cc to 250 cc.

  The accumulator 36 is used for buffering and temporarily storing refrigerant (and refrigerating machine oil), gas-liquid separation, foreign matter removal, and the like. The refrigerant (gas refrigerant) and oil from the evaporator 32 are temporarily stored in the accumulator. The gas refrigerant is supplied to the inlet 34b of the compressor 34, and the oil is returned to the compressor 34 little by little. The accumulator 36 has a liquid storage capacity of 200 cc, for example.

  In the heat pump 31 configured as described above, during the drying operation, the compressor 34 is driven, so that the gas refrigerant discharged from the compressor 34 is condensed in the condenser 33 to be a liquid refrigerant. The liquid refrigerant is expanded by the expansion valve 35 to form a mist, and the mist refrigerant is vaporized by heat exchange with the outside air in the evaporator 32, sent to the accumulator 36, and the gaseous refrigerant is compressed by the compressor 34. Thus, the circulation is performed such that the discharge is performed at a high temperature and a high pressure.

  At this time, due to the circulation of the air accompanying the rotation driving of the circulation fan 30 described above, the air containing a large amount of steam by removing moisture from the laundry in the water tank 3 (the rotation tank 5) is contained in the ventilation duct 26. By cooling through the evaporator 32 portion, the vapor is condensed (or sublimated) and dehumidified, and the dehumidified air is heated by passing through the condenser 33 portion to become dry warm air, and again the rotating tank 5 It is supplied inside and used for drying laundry.

  FIG. 4 is a block diagram schematically showing the electrical configuration of the washing / drying machine 1 described above. Here, the washing / drying machine 1 is provided with a control device 40 that is configured mainly with a microcomputer and controls the whole. The control device 40 includes an operation input unit 41 for a user to make various settings and instructions, a water level sensor 21, a discharge temperature sensor 42 that detects the temperature of the outlet 34 c of the compressor 34, and the condenser 33. A condenser temperature sensor 43 for detecting the temperature, an evaporator inlet temperature sensor 44 for detecting the temperatures of the inlet portion and the outlet portion of the evaporator 32, an evaporator outlet temperature sensor 45, and the like are connected, and signals from these are input. It is like that.

  And the control apparatus 40 is the said water supply valve 16, the motor 13, the fan motor 29, the compressor 34, the expansion valve 35, via the drive circuit 46 according to the operation control program memorize | stored beforehand based on various input signals. The drain valve 20 and the like are controlled. At this time, the controller 40 controls the drive of the compressor 34 at a variable speed by, for example, inverter control. Thus, a washing process including washing, rinsing, dehydration and the like and a subsequent drying process are automatically executed by the control device 40.

  The control device 40 functions as a compressor control means for controlling the rotation speed (inverter operating frequency) of the compressor 34 at a variable speed during the drying process due to its software configuration. In the embodiment, the following control is performed as will be described later in the description of the operation (flowchart description).

  That is, when the drying process is started, the control device 40 starts up so as to gradually increase the rotation speed (operation frequency) of the compressor 34 in a certain time step (for example, 1 Hz is increased in 1 second), the target maximum The rotation speed is increased until reaching the rotation speed (target maximum frequency Rmax: 100 Hz, for example). Thereafter, for example, based on the detected temperature of the discharge temperature sensor 42 and the condenser temperature sensor 43 and the input current value of the compressor 34, the input current value becomes larger than a predetermined value, or the detected temperature of the temperature sensors 42, 43. When the temperature reaches a predetermined temperature, the operating frequency of the compressor 34 is controlled such that the operating frequency is decreased by, for example, 5 Hz.

  In this embodiment, after a predetermined time T (for example, 30 minutes) has elapsed from the start of the drying process, the compressor 34 is moved to a predetermined rotational speed (predetermined frequency Rt) lower than the target maximum rotational speed (frequency Rmax). : For example, 85 Hz) or less. That is, when the operation frequency of the compressor 34 is higher than the predetermined frequency Rt at the time when the predetermined time T has elapsed from the start of the drying process, control is performed to forcibly lower the operation frequency to the predetermined frequency Rt. is there. The predetermined time T and the predetermined frequency Rt at this time are obtained in advance experimentally or empirically.

  Next, the operation of the above configuration will be described with reference to FIGS. In the washing / drying machine 1 having the above-described configuration, for example, when a standard operation course is started, a washing process is first executed as known, and then a drying process is subsequently executed. In the drying process, as described above, the rotating tub 5 is rotated in both forward and reverse directions at a low speed, and the circulation fan 30 is driven by the fan motor 29. At the same time, the compressor 34 is driven and the heat pump 31 is operated.

  As a result, as indicated by arrows in FIGS. 1 and 2, the air in the water tank 3 (the rotating tank 5) reaches the ventilation duct 26 from the exhaust port 23 through the exhaust duct 28, and the evaporator 32 and the condenser 33. Then, the air flows through the air supply duct 27 and is supplied into the rotary tank 5 through the air supply port 22 and the air vent 24. At that time, in the ventilation duct 26, the air containing moisture is cooled by the evaporator 32 portion in the ventilation duct 26 and the vapor is condensed (or sublimated) to be dehumidified, and the dehumidified air is converted into the condenser 33 portion. The laundry in the rotating tub 5 is dried efficiently with less wrinkles and shrinkage by being heated and dried to become a relatively low temperature hot air.

  Although illustration and detailed explanation are omitted, in this drying process, for example, the opening degree of the expansion valve 35 is controlled based on the detected temperatures (detected temperature difference) of the evaporator inlet temperature sensor 44 and the evaporator outlet temperature sensor 45. Is called. In addition, this drying process is terminated when a set time (for example, 90 minutes) elapses from the start of the drying process or when a drying completion is detected by temperature detection.

  Here, in the heat pump 31 of the present embodiment, the compressor 34 is downsized in the height direction (changed from 235 mm to 170 mm) compared to the conventional one. Along with this, the amount of oil enclosed has also been reduced from the conventional 370 cc to 250 cc. For this reason, if the rotation speed (operating frequency) control similar to the conventional control is performed with respect to the compressor 34, the amount of oil flowing out of the compressor 34 is greater than the amount flowing in after a predetermined time has elapsed since the start of the drying process. Many things happen. As a result, it is not possible to ensure a minimum reference height H (or H + 1.5 mm) of the required oil level in the frame 34a of the compressor 34, and there is a possibility that the operation of the compressor 34 may be hindered.

  FIG. 5 shows the result of the experiment conducted by the present inventor in the washing / drying machine 1 equipped with the heat pump 31 from the start of the drying process when the rotation speed (operating frequency) control similar to that of the conventional compressor 34 is performed. The relationship between the fluctuation | variation of the operating frequency of the compressor 34 with the passage of time, and the fluctuation | variation of the oil level in the flame | frame 34a of the compressor 34 is shown. FIG. 5 also shows the refrigerant circulation flow rate after 30 minutes from the start of the drying process and the inlet density of the compressor 34.

  From this result, as time elapses from the start of the drying process, the amount of oil flowing out of the compressor 34 becomes larger than the amount flowing in, and the oil level in the frame 34a gradually decreases. After about 30 minutes, the oil level in the frame 34a became lower than the target height (minimum reference height H + 1.5 mm). However, if the operation of the heat pump 31 (compressor 34) is continued thereafter, the amount of oil returned to the compressor 34 increases, and a desirable oil level is obtained after about 55 minutes from the start of the drying process. It became so.

  At this time, at about 30 minutes after the start of the drying process, the rotational speed of the compressor 34 is relatively high (close to the target maximum frequency Rmax (100 Hz)). The operating frequency of the compressor 34 was lowered to 85 Hz or less after 55 minutes from the start of the drying process, that is, when the oil level was returned to the desired oil level.

  Therefore, in this embodiment, the operation frequency of the compressor 34 is controlled by setting the predetermined time T to 30 minutes, for example, and the predetermined frequency Rt to 85 Hz, for example. The flowchart of FIG. 6 shows the processing procedure of the rotation speed (frequency) control for the compressor 34 executed by the control device 40 in the drying process.

  That is, when the drying process is started, first, in step S1, the rotation speed (operating frequency) of the compressor 34 is set to a target maximum frequency Rmax (100 Hz) in a certain time step (for example, 1 Hz is increased in 1 second). Is raised. When the operating frequency of the compressor 34 reaches the target maximum frequency Rmax, thereafter, in step S2, the input current value of the compressor 34 reaches the upper limit value or the detected temperature of the discharge temperature sensor 42 reaches the upper limit value. Whether or not the temperature detected by the condenser temperature sensor 43 has reached the upper limit value is always monitored.

  Here, when any of the input current value, the discharge temperature, and the condenser temperature of the compressor 34 has reached the upper limit (Yes in step S2), the operation frequency of the compressor 34 is determined in the next step S3. The voltage is lowered by a certain value (for example, 5 Hz), and the process returns to step S2. If none of the input current value, discharge temperature, and condenser temperature of the compressor 34 has reached the upper limit (No in step S2), the frequency of the compressor 34 is set to a constant frequency Rt (for example, 85 Hz) in step S4. ) It is determined whether or not it is less than or equal to Rt or less (Yes), the process returns to step S2.

  When the frequency of the compressor 34 exceeds the fixed frequency Rt (No in step S4), in the next step S5, a fixed time T (for example, 30 minutes) from the start of operation of the compressor 34 (start of the drying process). ) Has passed. If the predetermined time T has not yet elapsed (No in step S5), the process returns to step S2. On the other hand, when the fixed time T has elapsed (Yes in step S5), the frequency of the compressor 34 is lowered to the fixed frequency Rt (85 Hz) in step S6, and the process returns to step S2.

  By such control, when a certain time T (30 minutes) has elapsed from the start of the drying process, the frequency of the compressor 34 can be suppressed to a certain frequency Rt (85 Hz) or less, that is, the oil level may be lowered. At a certain point in time, the operating frequency of the compressor 34 is forcibly lowered, the amount of oil flowing out is suppressed, and the amount of oil flowing out from the compressor 34 and the amount of oil flowing in are equalized. can do. Thereby, the preferable oil level height (minimum reference height H + 1.5 mm) in the frame 34a of the compressor 34 can always be maintained.

  Therefore, according to the present embodiment, it is possible to prevent a malfunction of the compressor 34 due to a decrease in the oil level of the oil in the frame 34a, while suppressing a decrease in the performance of the heat pump 31, and as a result. The compressor 34 can be downsized in the height direction, and as a result, the entire washer / dryer 1 can be reduced in size and weight. At this time, it is possible to prevent problems associated with downsizing of the compressor 34 by controlling the compressor 34 without adding a configuration, and it is possible to reduce the cost.

(2) Second Example and Other Examples Next, a second example of the present invention will be described with reference to FIGS. Also in this embodiment, the present invention is applied to a drum-type washing / drying machine, and the basic configuration of the washing / drying machine 1 is the same as that of the first embodiment. , The same reference numerals are attached, new illustrations and detailed descriptions are omitted, and only different points will be described below.

  The second embodiment differs from the first embodiment in the configuration of the accumulator 51 that constitutes the heat pump 31 and the control device 40 as compressor control means that controls the operation of the compressor 34 at a variable speed. This is a software configuration, that is, a method of controlling the compressor 34 in the drying process.

  That is, as shown in FIG. 7, the accumulator 51 of the present embodiment has a cylindrical container shape that can accommodate a liquid, and an inlet pipe into which refrigerant (and refrigeration oil) from the evaporator 32 flows into the upper end thereof. 52 is connected. In addition, a filter member 53 such as a wire net for removing foreign matter is provided in the upper part of the accumulator 51. An outlet pipe 54 serving as an outlet for the gas refrigerant is connected to an upper portion of the accumulator 51 (just below the filter member 53), extends downward and then bends, and is connected to an inlet portion 34b of the compressor 34. Further, the accumulator 51 is provided with an oil return hole 51a connected to the outlet pipe 54 at the lower end portion in order to return oil to the compressor 34 little by little.

  The accumulator 51 is smaller than the conventional one (and the accumulator 36 of the first embodiment), and the storage capacity of liquid (liquid refrigerant and oil) is reduced from 50 cc to 50 cc. Has been. In this case, the accumulator 51 is used so that the liquid level of the liquid (liquid refrigerant and oil) accommodated therein is lower than the connection portion of the outlet pipe 54. If the pressure exceeds the value, the liquid refrigerant correspondingly overflows from the outlet pipe 54 and is sucked into the compressor 26.

  Here, when the accumulator 51 is miniaturized in this way, the storage capacity of the liquid becomes small. Therefore, at the start of the drying process (when the operation of the compressor 34 starts), the compressor as in the conventional case (see FIG. 9). When the operation frequency 34 is controlled, the return amount of the liquid refrigerant (and oil) to the accumulator 51 increases to a level that cannot be accommodated by the accumulator 51, and the liquid refrigerant overflows and is sucked into the compressor 26. As a result, the operation of the compressor may be hindered. This is because refrigerant and oil remaining in the condenser 33 and the evaporator 32 when the heat pump 31 is stopped because the degree of increase in the rotational speed (operation frequency) at the start of operation of the compressor 34 is relatively rapid. However, it is because it tries to return to the compressor 34 side suddenly.

  Therefore, in this embodiment, the control device 40 sets the rotation speed (operating frequency) of the compressor 34 at the initial stage of the drying process to the rotation speed (operating frequency when the accumulator 36 having a large capacity) is used normally. ) Is controlled so as to increase toward the target maximum frequency Rmax so that the increase degree is more gradual (slower speed) than the increase degree.

  More specifically, in the first embodiment, a certain time step (for example, 1 Hz is increased in 1 second) from the start of the drying process until the operating frequency of the compressor 34 reaches the target maximum frequency Rmax (100 Hz). The operating frequency of the compressor 34 is increased. On the other hand, in the present embodiment, the operation frequency of the compressor 34 is increased in a predetermined time step (for example, 1 Hz is increased in 1 second). However, the operation frequency of the compressor 34 is When the intermediate frequency R1 (for example, 30 Hz) is reached, the first intermediate frequency R1 is maintained for a certain time (for example, 3 minutes).

  Then, after a certain period of time has elapsed, the operating frequency of the compressor 34 is also increased in a certain time step, and this time, when the second intermediate frequency R2 (for example, 60 Hz) is reached, for the certain period of time (for example, 3 minutes). 2 intermediate frequency R2 is maintained. Thereafter, the frequency of the compressor 34 is increased to the target maximum frequency Rmax (100 Hz) in a predetermined time step. After that, the same control as in the first embodiment (FIG. 6) is performed.

  The flowchart of FIG. 8 shows the processing procedure of the rotation speed (frequency) control for the compressor 34 executed by the control device 40 in the drying process in the present embodiment. When the drying process is started, first, in step S11, the rotation speed (operating frequency) of the compressor 34 is increased in a certain time step (for example, 1 Hz is increased in 1 second), and in step S12, It is determined whether the operating frequency of the compressor 34 has reached the first intermediate frequency R1 (30 Hz). If the first intermediate frequency R1 (30 Hz) has not been reached (No in step S12), the process returns to step S11.

  When the operating frequency of the compressor 34 reaches the first intermediate frequency R1 (30 Hz) (Yes in Step S12), the first intermediate frequency R1 is maintained for a certain time (for example, 3 minutes) in Step S13. Become so. Thereafter, in step S14, it is determined whether or not the operating frequency of the compressor 34 has reached the second intermediate frequency R2 (60 Hz). If not (No in step S14), in step S15. The operation frequency of the compressor 34 is increased by a certain time step.

  When the operating frequency of the compressor 34 reaches the second intermediate frequency R2 (60 Hz) (Yes in step S14), in step S16, the second intermediate frequency R2 is maintained for a certain time (for example, 3 minutes). Will be maintained. Thereafter, in step S17, the operating frequency of the compressor 34 is increased by a predetermined time step until the target maximum frequency Rmax (100 Hz) is reached. Although the description is omitted after the operating frequency of the compressor 34 reaches the target maximum frequency Rmax, the processes of Steps S2 to S6 similar to those described in the first embodiment are performed.

  By such control, the refrigerant remaining in the condenser 33 and the evaporator 32 is reduced at the rise of the drying process (at the start of operation of the compressor 34) by slowing the increase in the operation frequency of the compressor. And it can suppress that oil tries to return to the compressor 34 side suddenly. Therefore, at the beginning of the drying process, the return amount of the liquid refrigerant and oil increases, and the accumulator 51 overflows without being accommodated and the liquid refrigerant is prevented from being sucked into the compressor 34 in advance. Can do. After that, control equivalent to that in the first embodiment is performed on the compressor 34, so that the compressor 34 can be reduced in size and the amount of oil filled can be reduced. The preferable oil level height (minimum reference height H + 1.5 mm) in the frame 34a can always be maintained.

  In this embodiment, the time from the start of operation of the compressor 34 to the target maximum frequency Rmax (7 minutes 40 seconds) seems to be slightly longer than the conventional time (2 minutes 40 seconds) shown in FIG. However, when viewed from the time required for the entire drying process (for example, 90 minutes), it is only a very short time, and does not cause a problem as a reduction in the capacity of the heat pump 31.

  As a result, according to the present embodiment, it is possible to prevent the liquid refrigerant from being sucked into the compressor 34 and causing a malfunction due to the downsizing of the accumulator 51 while suppressing the deterioration of the performance of the heat pump 31. Therefore, the accumulator 51 can be reduced in size. At this time, in combination with the downsizing of the compressor 34 in the height direction, the washing and drying machine 1 as a whole can be more effectively reduced in size and weight. In this case as well, it is possible to prevent problems associated with the downsizing of the accumulator 51 by controlling the compressor 34 without adding another configuration, and the cost can be reduced.

  In the second embodiment, the compressor 34 is controlled to maintain the frequency at the intermediate frequencies R1 and R2 twice before reaching the target maximum frequency Rmax (100 Hz). The intermediate frequency may be provided in three or more stages. Further, the time for maintaining the intermediate frequency is not limited to 3 minutes, and may be 1 minute, 2 minutes, or 4 minutes or more. Furthermore, instead of maintaining the frequency at the intermediate frequency, control may be performed such that the degree of frequency increase until reaching the target maximum frequency Rmax is lowered, for example, 1 Hz is increased every 2 seconds.

  And the capacity of the accumulator, the height dimension of the compressor 34, the operating frequency (the number of revolutions) of the compressor 34, the predetermined frequency Rt, the target maximum frequency Rmax, the amount of refrigeration oil enclosed, Specific numerical values such as the time required for the process are merely examples, and an optimal numerical value may be set on the manufacturer side according to the actual machine. Also as a configuration of the heat pump, another decompression means such as a capillary tube can be employed instead of the expansion valve. In addition, the present invention is not limited to a drum-type washing / drying machine, and can be applied to all washing / drying machines having a drying function using a heat pump. To get.

1 shows a first embodiment of the present invention, and is a longitudinal side view schematically showing an overall configuration of a washing / drying machine. The figure which shows typically the structure of a heat pump and an air circulation mechanism. Schematic diagram of compressor and accumulator Block diagram schematically showing the electrical configuration centering on the controller The figure which shows the experimental result which investigated the relationship between the fluctuation | variation of the operating frequency of a compressor, and the fluctuation | variation of the oil level height when the operating frequency control similar to the past was performed regarding a small compressor Flow chart showing the processing procedure of frequency control of the compressor in the drying process The figure which shows the 2nd Example of this invention and shows the structure of an accumulator roughly 6 equivalent diagram The figure which shows a prior art example and shows the relationship between the time passage in the initial stage of the drying process and the operating frequency of the compressor

Explanation of symbols

  In the drawings, 1 is a washing / drying machine, 5 is a rotating tub (washing tub), 25 is an air circulation mechanism, 26 is a ventilation duct, 27 is an air supply duct, 28 is an exhaust duct, 30 is a circulation fan, 31 is a heat pump, 32 is an evaporator, 33 is a condenser, 34 is a compressor, 35 is an expansion valve (decompression means), 36 and 51 are accumulators, 37 is a refrigerant pipe, and 40 is a control device (compressor control means).

Claims (2)

A laundry tub in which laundry is stored;
A heat pump in which a compressor, a condenser, a decompression means, an evaporator, and an accumulator are connected in a closed loop by a refrigerant line;
An air circulation mechanism that circulates the air in the washing tub through the evaporator and the condenser in order and returns the air to the washing tub when performing the drying process;
Compressor control means for controlling the operation of the compressor at a variable speed,
The compressor control means performs control so that the compressor is operated at a predetermined rotation speed lower than a target maximum rotation speed after a predetermined time has elapsed from the start of the drying process. Machine. A laundry tub in which laundry is stored;
A heat pump in which a compressor, a condenser, a decompression means, an evaporator, and an accumulator are connected in a closed loop by a refrigerant line;
An air circulation mechanism that circulates the air in the washing tub through the evaporator and the condenser in order and returns the air to the washing tub when performing the drying process;
Compressor control means for controlling the operation of the compressor at a variable speed,
In the initial stage of the drying process, the compressor control means directs the rotational speed of the compressor toward the target maximum rotational speed so that the rotational speed is moderately increased compared to the normal rotational speed. Washing and drying machine characterized by performing control to raise the

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