JPH1043498A - Clothes dryer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the need of time for raising a temperature again since the temperature inside a drum is lowered too much at the time of turning OFF a heater so as to suppress heating in the case a room temperature is low. SOLUTION: When a substrate temperature is less than a reference temperature, until an exit temperature detected by an exit temperature sensor disposed near the air exit of the drum reaches a high limiter temperature TH, the three pieces of the heaters are turned ON and the temperature is raised (a) [I] period}. When the exit temperature reaches the temperature TH, the two heaters are turned ON an one heater is turned OFF. Thus, the exit temperature is gently lowered (a) [II] period}. When the exit temperature is lowered to TH-1 deg.C, the three heaters are turned ON again (a) [III] period}. When temperature rise continues even when one heater is turned OFF, all the heaters are turned OFF when the exit temperature reaches TH+4 deg.C (b)[III] period}. By such control, the range of temperature fluctuation is made small and the cloth damages of clothes are reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a clothes dryer.

[0002]

2. Description of the Related Art A household clothes dryer dries and dries by supplying dry hot air to a drum containing wet clothes and cooling the wet hot air containing moisture evaporated from the clothes. The air is reheated by a heater and circulated to the drum. The drum is rotated slowly about a horizontal axis, which causes the clothes in the drum to be agitated and an even drying to be performed.

In such a clothes dryer, ON / OFF control of a heater is performed in order to realize good drying. Conventionally known clothes dryers use, for example, two heaters composed of a positive temperature coefficient thermistor, and use two heaters based on a drum exit temperature detected by a temperature sensor provided near the exit of the drum. ON / OFF
Is controlled.

Specifically, both heaters are turned on until the drum outlet temperature reaches a predetermined temperature, and if the drum outlet temperature reaches a predetermined upper limit temperature, further increase in the temperature is suppressed. Then, both heaters are turned off.
When the temperature at the outlet of the drum falls to a predetermined lower limit temperature, the two heaters are turned on again to perform reheating. Also, when drying clothing made of fibers that are vulnerable to heat or a small amount of clothing, in particular, "low heater" can be selected for drying at low temperatures. When "low heater" is selected, one heater is used. Is always turned off, and the other heater is turned on / off to perform drying.

[0005]

However, according to the above-described heating control, there are the following problems when the ambient temperature of the clothes dryer, that is, the room temperature, is low. That is,
When the room temperature is low, the temperature of the outside air taken in to cool the circulating air inside the dryer is low, so that the temperature of the air sent to the heater also becomes relatively low. Therefore, when the drum outlet temperature reaches a predetermined upper limit temperature and the heater is turned off, cool air is supplied to the drum, so that the temperature in the drum rapidly decreases. That is, when the room temperature is low, the temperature drop after the heater is turned off is sharper than when the room temperature is high.

[0006] Although the outlet temperature sensor can detect that the drum outlet temperature has dropped to a predetermined lower limit temperature, if the temperature of the air circulated to the heater is low, the air is supplied into the drum even when the heater is turned on. The temperature of the air produced does not rise immediately. For this reason, the temperature in the drum temporarily drops significantly beyond the predetermined lower limit temperature. That is, although the heater ON / OFF should be controlled so that the drum outlet temperature falls within the range between the lower limit temperature and the upper limit temperature, the temperature inside the drum fluctuates more than this temperature range. Such a large fluctuation in temperature causes damage to clothes.

Further, once the temperature in the drum is too low, the rise in temperature after turning on the heater is slow, and it takes time to raise the temperature. For this reason, the amount of heat given to the clothes is relatively reduced, and the drying performance is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a clothes dryer with less damage to clothes and good drying efficiency even at a low room temperature. It is in.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a clothes dryer of the present invention sends hot air heated by a heater to a rotating drum containing clothes and passes through the inside of the drum. A clothes dryer for circulating the drying air to the drum after cooling and dehumidifying the air, wherein: a) first temperature detecting means for detecting an outlet temperature which is a temperature of hot air immediately after passing through the drum; b) room temperature The second is to detect the ambient temperature that is the temperature corresponding to
Temperature detecting means; c) determining means for determining whether the detected temperature of the first temperature detecting means has reached a predetermined temperature; d) a plurality of heaters for heating air supplied to the drum; E) heating control means for controlling energization of the heater, wherein when the ambient temperature detected by the second temperature detecting means is lower than a predetermined temperature, the outlet temperature is first set to the first temperature by the determining means. Until the predetermined temperature is reached, all of the plurality of heaters are energized.
When the predetermined temperature is reached, the power supply to at least one of the plurality of heaters is stopped, and the outlet temperature further rises to reach a second predetermined temperature set higher than the first predetermined temperature. When reaching, the power supply to all the heaters is stopped, and when the outlet temperature falls to a third predetermined temperature set to a temperature lower than the first predetermined temperature, all of the plurality of heaters are turned off. And a heating control means for energizing the current.

[0010] In the above-mentioned clothes dryer, the heating control means, when the atmospheric temperature detected by the second temperature detecting means is higher than a predetermined temperature, sets the outlet temperature to the first predetermined temperature by the determining means. Until the temperature reaches the temperature, all of the plurality of heaters are energized, and the outlet temperature becomes the first temperature.
When the predetermined temperature is reached, the power supply to all the heaters is stopped, and when the outlet temperature decreases to reach the third predetermined temperature, all of the plurality of heaters are powered. .

In the above-mentioned clothes dryer, the first predetermined temperature is a value different depending on the operating conditions such as the atmospheric temperature, the elapsed time from the start of the operation, and the like, and the second predetermined temperature and the third predetermined temperature are different. Are characterized by values having a certain temperature difference with respect to the first predetermined temperature.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A clothes dryer according to the present invention includes two or more heaters, and energization of each heater is controlled by heating control means. When the ambient temperature detected by the second temperature detecting means is lower than a predetermined temperature, the determining means determines whether the outlet temperature detected by the first temperature detecting means is equal to three preset first, second and third temperatures. It is determined whether or not a predetermined temperature has been reached. Then, the heating control means determines the number of heaters to be energized based on the determination result.

For example, when the number of the heaters is three, the heating control means first energizes all of the three heaters until the outlet temperature first reaches the first predetermined temperature.
This causes the outlet temperature to rise. When the outlet temperature reaches the first predetermined temperature, the heating control unit stops energizing one of the three heaters and continues energizing the remaining two heaters. . When the room temperature is low, the temperature of the outside air that cools the hot air that has passed through the drum is low and the cooling effect is high. Therefore, only by stopping the power supply to one heater, the drum outlet temperature starts to gradually decrease. However, the rise of the outlet temperature may continue for some reason, for example, intake of outside air for cooling the circulating air is not smooth. In such a case, the outlet temperature is
When the predetermined temperature is reached, the heating control means stops supplying power to all the heaters. As a result, unheated air is supplied to the drum, so that the outlet temperature always starts to decrease. When the outlet temperature decreases to the third predetermined temperature,
The heating control means restarts heating by turning on the three heaters again.

Thereafter, by repeating the above control, the outlet temperature is usually in the range between the first predetermined temperature and the third predetermined temperature, and even when there is a problem in taking in outside air or the like. It falls in the range between the second predetermined temperature and the third predetermined temperature.

On the other hand, when the ambient temperature is equal to or higher than the predetermined temperature, the temperature of the outside air is high and the cooling effect is low. Even if the power supply to the power supply is stopped, the outlet temperature may continue to rise and exceed the second predetermined temperature.
This is not preferable from the viewpoint of safety as well as causing damage to the cloth. Therefore, when the ambient temperature is equal to or higher than the predetermined temperature, the judging means judges only whether or not the outlet temperature is equal to the first and third predetermined temperatures set in advance. The power supply to the heater is controlled based on the determination result.

For example, when the number of the heaters is three, the heating control means energizes all the three heaters until the outlet temperature reaches the first predetermined temperature, and the outlet temperature becomes the first temperature.
When the predetermined temperature is reached, the power supply to all the heaters is stopped. Then, when the outlet temperature falls to the third predetermined temperature, all three heaters are again energized.

[0017] In such a clothes dryer, the appropriate drying operation state can be changed depending on various conditions such as the amount of clothes, the type of fiber (easiness of drying), and room temperature. Therefore, the first predetermined temperature can be selected from different values according to the operating conditions such as the atmospheric temperature and the elapsed time from the start of operation, and the second predetermined temperature and the third predetermined temperature can be selected as the first predetermined temperature. In this case, if the temperature is set to a value having a certain temperature difference, the heating control can be performed so as to maintain the temperature in the drum almost constant near the appropriate temperature.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a clothes dryer according to the present invention will be described below with reference to FIGS. First, the overall configuration of the clothes dryer will be described with reference to a side vertical sectional view of FIG. In the center of the front of the machine frame 2 of the clothes dryer 1, a clothes inlet 3 is provided.
The opening is opened and closed by a door 4. A rear plate 5 is fixed to the back of the machine casing 2, and an intake port 6 for external air is formed substantially in the center of the rear plate 5. Meanwhile, machine frame 2
An air outlet 7 for air is formed on the lower surface of. In the machine frame 2, an annular sheet metal drum support plate 8 is attached so as to surround the clothes input port 3, and a support plate 9 is erected at a rear portion in a lateral direction with a predetermined interval from the rear plate 5. I have. A partly cut-out fan casing 10 is fixed to the support plate 9, whereby the inside of the machine frame 2 is divided into a fan chamber 11 and a drying chamber 12.

A horizontal shaft type drum 13 is provided in the drying chamber 12.
Is supported by a drum support plate 8 via a felt or the like with the front opening facing the clothes input port 3, and the rear side is rotatably supported by a main shaft 14. An air outlet 15 covered with a lint filter 16 is formed on the back surface of the drum 13, while an air inlet 17 is formed below the drum support plate 8 on the front surface. The support plate 9 has a drying room 12
A communication port 18 is formed between the drum 13 and the support plate 9 so that the air flow from the air outlet 15 reaches the communication port 18 without fail. .

In the fan chamber 11, a disk-shaped double-sided synthetic resin fan 20 is fixed to the main shaft 14, and a circulation fan 20a located on the drying chamber 12 side and a cooling fan 20b located on the rear panel 5 side. Are radially and integrally formed on both sides. A partition 21 is provided in the fan casing 10 so as to surround the double-sided fan 20.
The two-sided fan 20 is accommodated in the substantially central circular opening, so that the two-sided fan 20 and the partition 21 combine to partition the inside of the fan chamber 11 into a drying air passage 22 and a cooling air passage 23. A concentric rotating groove that opens toward the drying air passage 22 is formed integrally with the periphery of the double-sided fan 20.
A concentric fixing groove that opens toward the cooling air passage 23 is formed in the inner peripheral edge of the first fan 1, and the rotating groove of the double-sided fan 20 and the fixing groove of the partition 21 are loosely fitted in a non-contact state with each other. I have. That is, the rotating groove of the double-sided fan 20 and the fixing groove of the partition 21 form a labyrinth connection. For this reason, air cannot be exchanged between the drying air passage 22 and the cooling air passage 23.

A lower portion of the drying air passage 22 and an air inlet 17 formed in the drum support plate 8 are connected by a drying duct 24, and a heater 25 is disposed near the air inlet 17 inside the drying duct 24. ing. This heater 25
Is composed of, for example, a honeycomb-shaped positive characteristic thermistor. At the bottom of the drying duct 24, the drying duct 24
A drain port 26 for discharging the dehumidified water condensed into the outside of the machine
Is provided.

A motor 27 is provided at the bottom of the machine casing 2. The motor 27 applies a rotational force to a V-belt 32 wound around the outer peripheral surface of the drum 13 via a pulley 31, and a pulley 28 formed at the center of the cooling fan 20 b via a pulley 28 and a fan belt 29. Giving rotational force. Further, in order to prevent the V-belt 32 from slipping, the idler pulley 33 is driven by the V-belt 32 during rotation of the drum.
Apply appropriate tension to A rotation sensor 34 for detecting the number of rotations of the motor 27 is attached to the pulley 28.

During the drying operation, the drum 13 is driven at a low speed by the rotational driving force of the
Are rotated at high speed, and simultaneously, the heater 25 is energized to heat the drying air. Thereby, the wind generated by the rotation of the circulation fan 20a circulates through the drying air passage 22, the drying duct 24, and the drum 13, and the hot air is
Desorbs moisture from clothing when passing through. On the other hand, the rotation of the cooling fan 20b causes the outside air to flow from the intake port 6 to the cooling air path 2.
3 and discharged from the exhaust port 7. At this time, the double-sided fan 20 itself is cooled by the cool air. The hot air containing moisture after passing through the drum 13 contacts the double-sided fan 20 and is cooled, and condensed water flows down the inner wall of the drying air passage 22 and is discharged from the drain port 26.

An outlet temperature sensor 35 for detecting the temperature of air exhausted from the drum 13 is disposed near the air outlet 15 of the drum 13. Outlet temperature sensor 3
Numeral 5 is composed of a thermosensitive element such as a thermistor. An operation panel 36 provided with various input keys and a display is provided below the front of the machine casing 2. A synthetic resin substrate case 37 is attached to the inside of the machine casing 2 behind the operation panel 36 with screws, and the substrate case 37 is a member having a large heat capacity that is not easily affected by a sudden change in ambient temperature. A control board 38 composed of On the control board 38, a microcomputer (hereinafter referred to as "microcomputer") described later, an atmosphere temperature sensor 39 for detecting the temperature of the control board 38 itself, and other various electric components are mounted.

FIG. 2 is a front view showing the appearance of the operation panel 36. On the operation panel 36, a power key 40 for turning on the power, a start key 41 for instructing start and stop of the drying operation, and a drying course such as a "standard drying course" and a "slightly drying course" are selected. Input keys such as a course switching key 42 for selecting a heating intensity and a heating switching key 43 for selecting a heating intensity, and an LED for informing the selected course, the heating intensity, and the progress of the drying operation. A group 44, an electronic buzzer 45 for confirming operation of input keys and notifying an abnormality, and a display 46 for warning the clogging of the lint filter 16 are provided.

Next, the electrical configuration of the clothes dryer 1 will be described with reference to FIG. At the center of the control is the CPU 51,
ROM 52, RAM 53, timer 54, A / D converter 5
And a microcomputer 50 comprising a ROM 5 and the like.
The drying operation is performed by controlling each unit described below in accordance with an operation program stored in advance in Step 2. The microcomputer 50 includes an input key circuit 60 including input keys of the operation panel 36, a door switch 61 for detecting opening and closing of the door 4,
LED lighting circuit 62 for driving LED group 44 of operation panel 36, outlet temperature sensor 35, ambient temperature sensor 39,
A rotation speed detection circuit 63 including a rotation sensor 34, a buzzer circuit 64 for driving an electronic buzzer 45, a power supply circuit 65 connected to a commercial power supply, a commercial power supply zero-cross signal detection circuit 66 for detecting a zero-cross point of the commercial power supply, a motor 27, A load driving circuit 68 for driving the two heaters 25a and 25b and an automatic power-off circuit (APO) 67 for automatically shutting off power supply after the drying operation is completed;
Clock oscillation circuit 6 for generating a master clock signal
9, a reset circuit 70, and a current detection circuit 71 are connected.

FIG. 4 shows the outlet temperature T1 detected by the outlet temperature sensor 35 in the clothes dryer of this embodiment, and
Of the substrate temperature T2 detected by the ambient temperature sensor 39,
It is a figure which shows the change with respect to the drying operation time. Outlet temperature T
1 changes like the curve L1. That is, in the preheating period [i], the outlet temperature T1 gradually rises because the given amount of heat is used to increase the temperature of the dryer main body and the clothes containing much moisture. In the subsequent constant-rate drying period [ii], most of the applied heat is consumed for evaporating the moisture in the clothes, so that the outlet temperature T1 remains almost constant. In the reduced-rate drying period [iii], the supplied heat is consumed not only for evaporation of the water but also for the temperature rise of the clothes itself or the body of the dryer in which the water has been reduced, so that the outlet temperature T1 rises again.

In the decreasing rate drying period [iii], the outlet temperature T1 is equal to the high limiter temperature TH which is a predetermined upper limit temperature.
Normally, when the outlet temperature T1 falls within a predetermined temperature range, the outlet temperature T1 rises again when the outlet temperature T1 decreases to a lower limit temperature determined by a predetermined temperature difference α from the high limiter temperature TH, and so on. Back and forth between This is because ON / OFF control of the heater 25 as described later is performed.

On the other hand, the substrate temperature T2 changes as shown by a curve L2. That is, the substrate temperature T2 gradually rises for a while from the start of the operation, and changes to a substantially constant level after a certain period of time. This is because the control board 38 to which the ambient temperature sensor 39 is attached is a member having a large heat capacity which is affected by the ambient temperature itself but is not easily affected by the rapid change. This is because it almost depends on heat radiation of each electric component mounted on the board 38.

Hereinafter, in the clothes dryer having the above configuration, the ON / OFF control of the heater, which is a characteristic of the clothes dryer, will be mainly described.
The processing operation of the microcomputer 50 will be described with reference to the flowcharts of FIGS.

FIG. 5 is a flowchart showing the entire process of the drying operation. First, when the power key 40 is turned on (step S1), the microcomputer 50 receives a reset signal from the reset circuit 70 and performs an initial setting (step S2), thereby resetting various flags and variables. When the user puts the clothes in the drum 13 and presses the start key 41 (step S3), the microcomputer 5
0 indicates the initial target rotation speed of the motor 27, for example, 1150r.
pm and start the motor 27 (step S
4). Thereby, the rotation speed of the motor 27 rapidly increases to the target rotation speed, and the drum 13 and the double-sided fan 20 are rotated.
Rotates at a predetermined rotation speed determined by the respective reduction ratios.

Further, a heater setting process for determining the energization state of the heater 25 according to the temperature condition or the like is performed (step S5), and then the energization to the heater 25 determined in step S5 is controlled. Heater driving process is performed (step S6). Then, other processes necessary for the drying operation are executed (step S7). For example, the microcomputer 50 receives a signal of an analog value proportional to the power supply current including the motor 27 and the heater 25 detected by the current detection circuit 71 and converts the signal into an A / D converter 55.
Is converted into a digital value, and the target rotation speed of the motor 27 is corrected so that this value becomes a predetermined value. Then, the phase of the power supplied to the motor 27 is adjusted so that the target rotational speed is obtained.

Such a heater 25 and motor 27
After performing the control of (1), it is determined whether or not the drying operation has been completed (step S8). If the drying operation has not been completed, the process returns to step S5, and the processes of steps S5 to S8 are repeatedly performed. The drying operation is ended, for example, when a predetermined operation time has elapsed since the start of drying, or when the difference between the outlet temperature T1 and the substrate temperature T2 reaches a predetermined temperature difference set in advance. When the drying operation is completed, heater 2
5 is turned off (step S9), and a cool-down operation is executed to cool the hot clothing to a temperature at which it can be easily taken out (step S10). When the cool-down operation has been completed, the motor 27 is stopped and all the processes are completed.

Next, the heater setting process in step S5 will be described with reference to FIG. 9 and the flowcharts of FIGS. FIG. 9 is a diagram showing a change in the outlet temperature T1.

In the heater setting process, first, the substrate temperature T2 detected by the ambient temperature sensor 39 is set to the reference temperature T0.
(For example, T0 = 40 ° C.) or more (step S12). The substrate temperature T2 is a temperature substantially proportional to room temperature. That is, the level of the room temperature is determined in step S12, and the purpose of this determination is to change the method of ON / OFF control of the heater 25 according to the level of the room temperature, as described later. In step S12, the substrate temperature T
If it is determined that 2 is equal to or higher than the reference temperature T0, a reference temperature flag KF is set (step S13). Conversely, if it is determined that the substrate temperature T2 is lower than the reference temperature T0, the reference temperature flag KF is reset. (Step S14). That is, the reference temperature flag KF is a flag indicating that the substrate temperature T2 is equal to or higher than the reference temperature T0.

Next, it is determined whether or not the high limiter flag HF is set (step S15). The high limiter flag HF is a flag indicating that a high limiter temperature TH described later has already been determined, and is reset at the time of initial setting. Therefore, immediately after the start of the drying operation, the high limiter flag HF is “0”, and the process proceeds to the high limiter temperature TH determination processing (step S16).

The high limiter temperature TH is selected from predetermined values according to the operating time t at that time, the substrate temperature T2, and the current I. FIG. 10 is an example of a table prepared for selecting the high limiter temperature TH. Such a table is stored in the ROM 52 in advance, and when the operation time t, the substrate temperature T2, and the current I are input, the corresponding value of the high limiter temperature TH is output. Here, the current I is a current value detected by the current detection circuit 71, and is supplied to the clothes dryer including a drive current for driving the motor 27 and a drive current for heating the heater 25. This is the value obtained by detecting the total power supply current.

After the determination of the high limiter temperature TH, the temperature gradient flag DF is reset (step S17). The temperature gradient flag DF is a flag indicating whether the temperature is controlled to rise or fall, and is defined as a rising direction when the temperature is "0". Note that the temperature gradient flag DF indicates the direction of control, and does not always coincide with the actual rise and fall of the outlet temperature T1.

Next, it is determined whether or not the outlet temperature T1 is equal to or higher than the previously determined high limiter temperature TH + 4 ° C. (step S18). That is, in this embodiment, the high limiter temperature TH + 4 ° C. is defined as the highest upper limit temperature. If the outlet temperature T1 is equal to or higher than the high limiter temperature TH + 4 ° C. in step S18, the outlet maximum temperature flag MF is set (step S19). For a while after the start of the drying operation, the outlet temperature T1 is the high limiter temperature TH.
Therefore, the process proceeds to step S20 with the outlet maximum temperature flag MF being reset.

Subsequently, it is determined whether or not the temperature gradient flag DF is reset, that is, whether or not the temperature gradient is rising (step S20). Since the temperature gradient flag DF has been reset in step S17, the outlet temperature T
It is determined whether or not 1 is equal to or higher than the high limiter temperature TH (step S21). Here, since the outlet temperature T1 has not reached the high limiter temperature, step S27 (see FIG. 7)
Proceed to.

In step S27, it is determined whether or not the temperature gradient flag DF has been reset.
If it is determined that F has been reset, step S3
0, the process proceeds to S31, and if it is determined that the temperature gradient flag DF is set, the process proceeds to step S28. Until the outlet temperature T1 reaches the high limiter temperature TH for the first time, the temperature gradient flag DF continues to be reset in step S17, so the heater 1 flag is set in steps S30 and S31.
The heater 2 flag is set together. The heater 1 flag and the heater 2 flag indicate ON / OFF control of the first heater 25a and the second heater 25b, respectively.

In the heater driving process of step S6, which is performed after the heater 1 flag and the heater 2 flag are set in the heater setting process of step S5, as shown in the flowchart of FIG. Second
Power supply to the two heaters 25a and 25b is controlled. That is, in the heating heater driving process, first, it is determined whether or not the heater 1 flag is set (step S41). When the heater 1 flag is set, the first heater 25a composed of two thermistors is energized (step S42). When the heater 1 flag is reset, the first heater 25a is reset. Power supply to the heater 25a is stopped (step S43).

Next, it is determined whether or not the heater 2 flag has been set (step S44). When the heater 2 flag is set, the second heater 25b composed of one thermistor is energized (step S45). When the heater 2 flag is reset, the second heater 25b is reset. The power supply to the heater 25b is stopped (step S46). Therefore, step S30,
When both the heater 1 flag and the heater 2 flag are set in S31, the first and the second heater heater driving processes are performed.
Both of the second heaters 25a and 25b are turned on, and heating is performed by three thermistors.

When the heating is started as described above, heated air is supplied from the air inlet 17 into the drum 13, and the outlet temperature T1 rises (period [I] in FIG. 9A). Heater heater setting processing in step S5 and step S6
When the heater driving process is repeated, the first and second heaters 25a and 25b are energized through the same routine as described above until the outlet temperature T1 reaches the high limiter temperature TH. The state continues. Also, during this period, the high limiter flag HF is kept reset, and in step S16, the high limiter temperature TH corresponding to the current operation time t, substrate temperature T2 and current I is selected and updated. Is done.

When the operation proceeds through the preheating period and the constant-rate drying period to the reduced-rate drying period, and the outlet temperature T1 rises and reaches the high limiter temperature TH, the process proceeds from step S21 to S22 in the heater setting process. The high limiter flag HF is set (step S22), and the temperature gradient flag DF is set (step S2).
3). Since it is determined in step S27 that the temperature gradient flag DF has been set, next, the reference temperature flag KF
Is set (step S2).
8).

If it is determined in step S28 that the reference temperature flag KF is set, that is, if the substrate temperature T2 at that time is equal to or higher than the reference temperature T0, the process proceeds to steps S34 and S35, where the heater The 1 flag and the heater 2 flag are both reset. Thereby, in the heater driving process executed subsequently, the first and second heater driving processes are performed.
Heaters 25a and 25b are both turned off. That is, in this case, the outlet temperature T1 is equal to the high limiter temperature TH.
After it reaches, it surely turns downward.

On the other hand, if it is determined in step S28 that the reference temperature flag KF has been reset, that is, if the substrate temperature T2 at that time is lower than the reference temperature T0, the outlet maximum temperature flag MF is set. It is determined whether or not it has been performed (step S29). If it is determined in step S29 that the outlet maximum temperature flag MF has been reset, the outlet temperature T1 is set to the high limiter temperature + 4 ° C.
Since it can be determined that the temperature is less than the threshold, the heater 1 flag is set (step S32), and the heater 2 flag is reset (step S33). Accordingly, in the heater driving process that is subsequently performed, the first heater 25a
Is turned on, and the second heater 25b is turned off. That is, two of the three thermistors are ON
Is done.

When the outlet temperature T1 once reaches the high limiter temperature TH, the high limiter flag HF is set in step S22, so that in the subsequent heater setting process, the process proceeds from step S15 to S18. The high limiter temperature TH is not updated. That is, when the outlet temperature T1 first reaches the high limiter temperature TH, the high limiter temperature TH is fixed.

As described above, the substrate temperature T2 is equal to the reference temperature T0.
If one of the three thermistors that were previously ON is turned OFF when the temperature is lower than (for example, 40 ° C.), the temperature of the heated air supplied to the drum 13 from the air intake 17 decreases. . In particular, when the room temperature is low, the inlet 6
Since the temperature of the outside air taken in from the air is low, the cooling effect of the cooling fan 20b is high. Therefore, the outlet temperature T1 starts to decrease gradually (period [II] in FIG. 9A).

The outlet temperature T1 is equal to the high limiter temperature TH-1 ° C.
If the temperature falls below the threshold, the process proceeds from step S24 to S25, where the maximum outlet temperature flag MF is reset (step S25) and the temperature gradient flag DF is reset (step S26). In the following step S27, it is determined that the temperature gradient flag DF has been reset, and the process proceeds to steps S30 and S31, where the heater 1 flag and the heater 2
Set the flags together. As a result, in the heating heater driving process executed subsequently, both the first and second heating heaters 25a and 25b are turned on again.

When the substrate temperature T2 is equal to the reference temperature T0 (for example, 40
° C), as described above, when one of the three thermistors previously turned on is turned off, the outlet temperature T1 usually begins to drop. However, if an obstacle is placed outside the intake port 6 or if the intake is deteriorated due to dust or the like, the outlet temperature T1 does not decrease, and the temperature rise may be slowed down but continued to rise (FIG. 9 (b) [II] period). This allows
When the outlet temperature T1 reaches the high limiter temperature TH + 4 ° C,
In step S19, the outlet maximum temperature flag MF is set. Then, in step S29, it is determined that the outlet maximum temperature flag MF has been set, and the heater 1 flag and the heater 2 are set in order to prevent the outlet temperature T1 from further increasing.
The flag is reset together (steps S34, S3
5). Thereby, in the heater heater driving process executed subsequently, the first and second heaters 25a, 25b
Are both turned off. As a result, unheated cold air is supplied from the air inlet 17 to the drum 13, so that the outlet temperature T1 surely starts to decrease.

As described above, according to the heater setting process of FIGS. 6 and 7, when the substrate temperature T2 is lower than the reference temperature T0, the number of heaters is switched in the following procedure. (1) From the start of drying, the outlet temperature T1 is the high limiter temperature TH
(Period [I] in FIGS. 9A and 9B): Three heaters are turned on. (2) Period from when the outlet temperature T1 reaches the high limiter temperature TH to when it falls smoothly to the high limiter temperature TH-1 ° C. (period [II] in FIG. 9A): Two heaters are turned on.
I do. (3) A period until the outlet temperature T1 drops to the high limiter temperature TH-1 ° C. and then reaches the high limiter temperature TH again (the period [III] in FIG. 9A and the period [I] in FIG. 9B).
V] period): Three heaters are turned on.

When the outlet temperature T1 continues to rise in (2) and reaches the high limiter temperature TH + 4 ° C., the following control is performed instead of (2). (4) The period from when the outlet temperature T1 reaches the high limiter temperature TH to when it reaches the high limiter temperature TH + 4 ° C. (FIG. 9)
([II] period (b)): Two heaters are turned on. (5) A period from when the outlet temperature T1 reaches the high limiter temperature TH + 4 ° C. until it falls to the high limiter temperature TH-1 ° C. ((period [III] in FIG. 9B)):
FF.

On the other hand, when the substrate temperature T2 is equal to or higher than the reference temperature T0, the number of heaters is switched in the following procedure. (1) From the start of drying, the outlet temperature T1 is the high limiter temperature TH
Period until reaching: 3 heaters are turned on. (2) Period from when the outlet temperature T1 reaches the high limiter temperature TH until it falls to the high limiter temperature TH-1 ° C .: All heaters are turned off. (3) Period until the outlet temperature T1 drops to the high limiter temperature TH-1 ° C. and then reaches the high limiter temperature TH again: Three heaters are turned on.

That is, when the room temperature is low, if all the heaters 25 are turned off immediately after the outlet temperature T1 has reached the high limiter temperature TH, the outlet temperature T1 drops rapidly and the high limiter temperature TH- It quickly drops below 1 ° C. However, by turning on a part of the heater 25, the gradient of the temperature drop becomes gentle, and it becomes easy to maintain the outlet temperature T1 near the high limiter temperature TH. On the other hand, when the room temperature is high, if the outlet temperature T1 reaches the high limiter temperature TH, all the heaters 25 are turned off immediately so that the outlet temperature T1 does not greatly exceed the high limiter temperature TH. .

It should be noted that the above embodiment is merely an example, and it is apparent that modifications and modifications can be made as appropriate within the scope of the present invention.

[0057]

As described above, according to the clothes dryer of the present invention, when the room temperature is low, when the drum outlet temperature reaches a predetermined high limiter temperature and is controlled so as to decrease the temperature. Even in this case, at least one heater is kept energized. As a result, the temperature at the outlet of the drum gradually decreases, so that it is easy to control the temperature to fall within a narrow range. As a result, damage to the cloth of the clothing can be suppressed. Further, since the temperature does not drop below the lower limit temperature, the temperature can be quickly raised at the time of the next temperature rise, and the drying performance does not deteriorate.

Further, even if the temperature continues to rise even when the power supply to the other heaters is stopped while leaving at least one heater, the drum outlet temperature is set to a temperature higher than the high limiter temperature. When the temperature reaches the set temperature, the power supply to all the heaters is stopped. For this reason, since the temperature in a drum falls reliably, damage to clothing can be prevented.

When the room temperature is high, the power supply to all the heaters is stopped when the drum outlet temperature reaches the predetermined high limiter temperature. For this reason, it is possible to reliably prevent the drum outlet temperature from becoming too high.

Further, by appropriately changing the high limiter temperature in accordance with the conditions such as the operation time, it is possible to perform appropriate drying in accordance with the room temperature, the amount of clothing, the type of fiber, and the like. It is possible to suppress and eliminate uneven drying.

[Brief description of the drawings]

FIG. 1 is a side longitudinal sectional view of a clothes dryer according to an embodiment of the present invention.

FIG. 2 is a front view showing the appearance of an operation panel of the clothes dryer.

FIG. 3 is an electrical configuration diagram of the clothes dryer.

FIG. 4 is a diagram showing changes in outlet temperature and substrate temperature with respect to operation time during a drying operation.

FIG. 5 is a flowchart of the entire process of the drying operation in the clothes dryer.

FIG. 6 is a flowchart of a heater setting process in the clothes dryer.

FIG. 7 is a flowchart of a heater setting process in the clothes dryer.

FIG. 8 is a flowchart of a heater driving process in the clothes dryer.

FIG. 9 is a diagram showing a change in outlet temperature when the room temperature is low.

FIG. 10 is a diagram showing an example of a table used for a high limiter temperature determination process.

[Explanation of symbols]

 13 Drum 25a First heater 25b Second heater 27 Motor 35 Outlet temperature sensor 39 Atmospheric temperature sensor 50 Microcomputer 60 Input key circuit 68 Load drive circuit

Claims (3)

[Claims] 1. A clothes dryer in which hot air heated by a heater is sent to a rotating drum containing clothes, the air passing through the drum is cooled and dehumidified, and then the drying air is circulated through the drum. a) first temperature detecting means for detecting an outlet temperature which is the temperature of hot air immediately after passing through the drum; b) second temperature detecting means for detecting an ambient temperature which is a temperature corresponding to room temperature.
Temperature detecting means; c) determining means for determining whether the detected temperature of the first temperature detecting means has reached a predetermined temperature; d) a plurality of heaters for heating air supplied to the drum; E) heating control means for controlling energization of the heater, wherein when the ambient temperature detected by the second temperature detecting means is lower than a predetermined temperature, the outlet temperature is first set to the first temperature by the determining means. Until the predetermined temperature is reached, all of the plurality of heaters are energized.
When the predetermined temperature is reached, the power supply to at least one of the plurality of heaters is stopped, and the outlet temperature further rises to reach a second predetermined temperature set higher than the first predetermined temperature. When reaching, the power supply to all the heaters is stopped, and when the outlet temperature falls to a third predetermined temperature set to a temperature lower than the first predetermined temperature, all of the plurality of heaters are turned off. And a heating control means for supplying a current to the clothes dryer. 2. The heating control means according to claim 1, wherein when the ambient temperature detected by said second temperature detecting means is equal to or higher than a predetermined temperature, the heating control means determines whether the outlet temperature reaches a first predetermined temperature by said determining means. All of the plurality of heaters are energized, and when the outlet temperature reaches the first predetermined temperature, the energization of all heaters is stopped, and the outlet temperature decreases to reach the third predetermined temperature. 2. The clothes dryer according to claim 1, wherein all of the plurality of heaters are energized when the heating is performed. 3. The first predetermined temperature is a value that differs according to operating conditions such as the ambient temperature and the elapsed time from the start of operation, and the second predetermined temperature and the third predetermined temperature are the first predetermined temperature. 3. The clothes dryer according to claim 1, wherein the clothes dryer has a value having a certain temperature difference with respect to the temperature.