JP3717604B2 - Clothes dryer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a clothes dryer.
[0002]
[Prior art]
A domestic clothes dryer supplies dry hot air into a drum containing wet clothes, dehumidifies the air by cooling the wet hot air containing moisture evaporated from the clothes, and the dried air is heated by a heater. It is configured to reheat and circulate to the drum. The drum is rotated slowly about a horizontal axis, whereby the clothes in the drum are agitated and a uniform drying is performed. In general, such a clothes dryer is provided with a single motor for rotating a fan and a drum for generating a circulating air, respectively, and from the rotation shaft of the motor through a transmission mechanism such as a pulley and a V belt. Thus, the fan and drum are each driven to rotate at a predetermined rotational speed.
[0003]
[Problems to be solved by the invention]
In the clothes dryer, when a failure such as a short circuit occurs in the motor itself or the motor drive circuit, the motor stop control becomes impossible. For example, the user opens the door without noticing that the drum continues to rotate. In some cases, there was a problem that the clothes jumped out of the drum.
[0004]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a clothes dryer capable of reliably detecting a failure such as a motor short circuit with a simple configuration. .
[0005]
Means for Solving the Problem and Embodiment of the Invention
The present invention made to solve the above problems is a clothes dryer having a rotating drum,
a) a motor for rotating the drum;
b) drive control means for driving and controlling the motor;
c) a rotational speed detection means for detecting the rotational speed of the motor;
d) A motor detected by the rotation speed detection means within a first predetermined time during a period in which the motor is not controlled to rotate by the drive control means until the power is turned off after the drying operation is completed. Counting means for counting the number of rotations of
e) an abnormality detection means for determining whether or not the count value of the counting means exceeds a predetermined value;
f) notification means for notifying abnormality when the count value exceeds a predetermined value;
Equipped with a,
The counting means has a second predetermined time for the motor speed to drop sufficiently from the vicinity of the steady speed from the time when the drive control means controls to stop the rotation after the motor is driven to rotate. It is characterized in that counting of the rotation speed of the motor is started after waiting for this.
[0006]
Counting means, in a period in which the motor is not controlled to rotate by the drive control means to supply after the drying operation is finished is cut off, during a first predetermined time, obtained from the rotational speed detecting means motor The motor rotation (stop) status is grasped by counting pulse signals synchronized with the rotation. Normally, the motor should not rotate during this period, so the abnormality detection means compares the count value with a predetermined value, and if it exceeds the predetermined value, the motor rotates due to an abnormality such as a motor short circuit. Judge that there is. In response to this determination result, the notifying means issues a warning to the user visually or audibly. As a result, the user can recognize the abnormality and take appropriate measures such as shutting off the power.
[0007]
As described above, the abnormality detection means can detect abnormality in any period before and / or after the drying operation. However, for example, the operation start key is often operated immediately after the power is turned on by the user, and there is not always an opportunity to reliably detect the abnormality before the drying operation is started. For this reason, if abnormality detection is always performed at least after the drying operation, abnormality detection of the motor rotation can be reliably performed.
[0009]
Here, immediately after the drying operation is completed, since the motor is rotating at a substantially steady rotational speed, accurate abnormality detection cannot be performed unless the rotational speed is started after the rotational speed of the motor is appropriately reduced. . Therefore, the rotation speed is not counted until the second predetermined time has elapsed from the time when the motor rotation is controlled to be stopped, such as by interrupting the drive current supplied to the motor, and the second predetermined time has elapsed. The number of rotations of the motor within the first predetermined time is counted later. That is, since the second predetermined time is a margin time necessary for the motor rotation speed to sufficiently decrease from the vicinity of the steady rotation speed, it is appropriately determined in advance in relation to the predetermined value for determining the count value. .
[0010]
The predetermined value in the abnormality detecting means is determined in advance in consideration of not only the above conditions but also various situations. For example, even when the drive control of the motor is normal and the drum is originally stopped, there is a possibility that the user may apply force to intentionally rotate the drum. When the drum is rotated by an external force, the rotating shaft of the motor rotates through the V belt. However, when the drum is rotated by the user's force, the rotational speed of the motor does not become as high as that when driven by the drive control means. By setting an appropriate value that cannot be reached even if the drum is rotated, the motor is rotating when the motor is rotating due to an abnormality such as a short circuit or when the drum is intentionally rotated. The case can be distinguished.
[0011]
In the clothes dryer, even if the notification means gives an abnormality notification, the user is not always around the clothes dryer. In view of this, it is preferable to include a power shut-off means that automatically shuts off the power immediately or after a predetermined time when an abnormality is detected by the abnormality detection means. As a result, even if the user does not perform an operation to shut off the power, the power is shut off immediately or after a certain time in the event of an abnormality, so that the drum can be prevented from continuing to rotate for a long time.
[0012]
According to a clothes dryer according to the present invention, abnormality of the motor rotation due to a short circuit or the like of repeatedly motor after operation Drying is detected. For this reason, abnormality detection is reliably performed, and it is possible to prevent the user from opening the door without noticing that the drum continues to rotate after the drying operation is completed.
[0013]
Further, a cycle of one drying operation is performed by controlling the rotation to be stopped from a state in which the motor is driven to rotate, and detecting an abnormality after a second predetermined time has elapsed since that time. During this, the motor rotation abnormality detection is always executed. For this reason, after an abnormality occurs, the abnormality can be detected quickly. Further, it is possible to prevent an abnormality notification from being made even though it is not abnormal, and the reliability of abnormality detection is also increased.
[0014]
Furthermore, if the power supply is automatically shut down even if the power shutoff operation is not performed after the abnormality is detected, it is possible to prevent the drum from continuing to rotate for a long time.
[0015]
【Example】
Hereinafter, an embodiment of a clothes dryer according to the present invention will be described with reference to FIGS. First, the overall configuration of the clothes dryer will be described with reference to a side longitudinal sectional view of FIG. In the center of the front surface of the machine casing 2 of the clothes dryer 1, a clothes insertion port 3 is provided, and the opening thereof is opened and closed by a door 4. A rear plate 5 is fixed to the rear surface of the machine frame 2, and an air inlet 6 for external air is formed in the approximate center of the rear plate 5. On the other hand, an air exhaust port 7 is formed on the lower surface of the machine casing 2. Inside the machine frame 2, an annular sheet metal drum support plate 8 is attached so as to surround the clothing insertion port 3, and a support plate 9 is installed in the rear side in a lateral direction with a predetermined distance from the rear plate 5. Yes. A fan casing 10 with a part cut away is fixed to the support plate 9, whereby the machine casing 2 is partitioned into a fan chamber 11 and a drying chamber 12.
[0016]
In the drying chamber 12, a horizontal shaft type drum 13 is supported on the drum support plate 8 via a felt or the like with the front opening facing the clothing insertion port 3, and the rear surface is rotatably supported by the main shaft 14. It is supported. An air outlet 15 covered with a lint filter 16 is formed on the rear surface of the drum 13, while an air intake port 17 is formed on the lower portion of the drum support plate 8 on the front surface. The support plate 9 is formed with a communication port 18 that allows the drying chamber 12 and the fan chamber 11 to communicate with each other. The seal member 19 is connected to the drum 13 and the support plate 9 so that the air flow from the air outlet 15 reaches the communication port 18 with certainty. It is attached between.
[0017]
In the fan chamber 11, a disk-shaped synthetic resin double-sided 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 plate 5 side are respectively radial. It is formed integrally with the front and back. A partition wall 21 is provided in the fan casing 10 so as to surround the double-sided fan 20, and the double-sided fan 20 is accommodated in a circular opening substantially at the center of the partition wall 21. 11 is divided 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 integrally formed on the periphery of the double-sided fan 20, while a concentric fixing groove that opens toward the cooling air passage 23 is formed on the inner periphery of the partition wall 21. The rotating groove of the double-sided fan 20 and the fixed groove of the partition wall 21 are loosely fitted in a non-contact state. That is, the rotation groove of the double-sided fan 20 and the fixing groove of the partition wall 21 form a labyrinth connection. For this reason, the air cannot be exchanged between the drying air passage 22 and the cooling air passage 23.
[0018]
A lower portion of the drying air passage 22 and the air intake port 17 formed in the drum support plate 8 are connected by a drying duct 24, and a heater 25 is disposed in the vicinity of the air intake port 17 inside thereof. The heater 25 is composed of, for example, a honeycomb-shaped positive temperature coefficient thermistor. A drain outlet 26 for discharging dehumidified water condensed in the drying duct 24 to the outside of the machine is provided at the lowermost part of the drying duct 24.
[0019]
A motor 27 is disposed at the bottom of the machine frame 2. The motor 27 applies a rotational force to the V-belt 32 wound around the outer peripheral surface of the drum 13 via a pulley 31, while a pulley 30 formed at the center of the cooling fan 20 b via a pulley 28 and a fan belt 29. Giving rotational force. In order to prevent the V belt 32 from slipping, the idler pulley 33 applies an appropriate tension to the V belt 32 when the drum rotates. A rotation sensor 34 for detecting the rotation speed of the motor 27 is attached to the pulley 28.
[0020]
Thus, during the drying operation, the drum 13 is rotated at a low speed and the double-sided fan 20 is rotated at a high speed by the rotational driving force of the motor 27. At the same time, the heater 25 is energized to heat the drying air. As a result, the wind generated by the rotation of the circulation fan 20 a circulates through the drying air path 22, the drying duct 24, and the drum 13, and deprives moisture from the clothing when the hot air passes through the drum 13. On the other hand, by the rotation of the cooling fan 20 b, outside air is introduced into the cooling air passage 23 from the intake port 6 and discharged from the exhaust port 7. At this time, the double-sided fan 20 itself is cooled by cold air. The hot air containing moisture after passing through the drum 13 is cooled by contacting the double-sided fan 20, and the condensed water flows down the inner wall of the drying air passage 22 and is discharged from the drain outlet 26.
[0021]
An outlet temperature sensor 35 for detecting the temperature of the air exhausted from the drum 13 is disposed in the vicinity of the air outlet 15 of the drum 13. The outlet temperature sensor 35 is composed of a thermal element such as a thermistor, for example. An operation panel 36 having various input keys and a display is provided below the front of the machine casing 2. A board case 37 made of synthetic resin is attached to the inside of the machine casing 2 behind the operation panel 36 with screws, and the board case 37 is a member having a large heat capacity that is not easily affected by a sudden change in the ambient temperature. The control board 38 comprised by is comprised internally. On the control board 38, a microcomputer (hereinafter referred to as “microcomputer”) described later, an ambient temperature sensor 39 for detecting the temperature of the control board 38 itself, and other various electrical components are mounted.
[0022]
FIG. 2 is a front view showing the appearance of the operation panel 36. On this operation panel 36, a power key 40 for turning on the power, a start key 41 for instructing start or pause of the drying operation, and a drying course such as “standard drying course” and “careful drying course” are selected. Input keys such as a course switching key 42 for heating and a heater 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 and an electronic buzzer 45 for confirming operation of the input keys and notifying abnormality are provided.
[0023]
Next, the electrical system configuration of the clothes dryer will be described with reference to FIG. At the center of the control is a microcomputer 50 comprising a CPU 51, ROM 52, RAM 53, timer 54, A / D converter 55, etc., and drying is performed by controlling each part described later in accordance with an operation program stored in the ROM 52 in advance. Run the operation. The microcomputer 50 includes an input key circuit 60 including input keys of the operation panel 36, a door switch 61 that detects opening / closing of the door 4, an LED lighting circuit 62 that drives the LED group 44 of the operation panel 36, an outlet temperature sensor 35, Atmospheric temperature sensor 39, rotation speed detection circuit 63 including rotation sensor 34, buzzer circuit 64 for driving electronic buzzer 45, power supply circuit 65 connected to commercial power supply, commercial power supply zero cross signal detection circuit for detecting zero cross point of commercial power supply 66, a motor 27, two heaters 25a, 25b, a load driving circuit 68 for driving an auto power off circuit (APO) 67 for automatically shutting off power supply after the drying operation is completed, a master clock signal Are connected to a clock oscillation circuit 69 for generating the signal and a reset circuit 70.
[0024]
Hereinafter, the processing operation of the microcomputer 50 will be described with reference to the flowcharts of FIGS. 4 to 6, focusing on the motor short circuit detection process that is a feature of the present invention.
FIG. 4 is an overall flowchart from power-on to power-off. First, when the power key 40 is turned on (step S1), the microcomputer 50 receives a reset signal from the reset circuit 70 and executes an initial setting process (step S2), thereby resetting various flags and variables. . And the motor short circuit detection process mentioned later is repeatedly performed until the start key 41 is pressed (step S3).
[0025]
When the user stores the clothes in the drum 13 and presses the start key 41 (step S4), the microcomputer 50 sets the motor target rotation speed to, for example, 1150 rpm, starts the motor 27, and starts energizing the heater 25. Then, the drying operation is started (step S5). Simultaneously with the start of the drying operation, the timer A for counting the operation time is started (step S6). As a result, the rotational speed of the motor 27 rapidly increases to the target rotational speed, and the drum 13 and the double-sided fan 20 rotate at a predetermined rotational speed determined by their respective reduction ratios.
[0026]
Next, various processes for the drying operation are executed (step S7). That is, when the drying operation is started, the microcomputer 50 receives temperature data of analog voltage values from the outlet temperature sensor 35 and the atmospheric temperature sensor 39, and converts them into digital voltage values by the A / D converter 55. Based on the temperature data, a control signal is output to the load drive circuit 68 so that the two heaters 25a and 25b are appropriately turned ON / OFF.
[0027]
Thereafter, it is determined whether or not the drying operation has been completed (step S8). If not, the process returns to step S7 to repeat the process for the drying operation. In the drying operation, for example, when the timer A reaches a predetermined operation time, or the temperature difference detected by the outlet temperature sensor 35 and the atmospheric temperature sensor 39 reaches a predetermined temperature difference set in advance. When it is finished.
[0028]
After the drying operation is completed, a cool-down operation is performed in order to cool the clothing that has become hot to a temperature at which it can be easily taken out (step S9). In the cool-down operation, the energization to the heaters 25a and 25b is interrupted while the drive control of the motor 27 is continued. For example, when the detected temperature of the outlet temperature sensor 35 reaches a predetermined temperature, or a predetermined cool-down time. The cool-down operation is terminated when elapses.
[0029]
After the cool-down operation is completed, the motor 27 is turned off (step S10), and the timer A for counting the operation time is reset and then restarted (step S11). And a motor short circuit detection process is performed similarly to said step S3 (step S12). Thereafter, it is determined whether or not the timer A has reached a predetermined auto power off time (step S13). If not, it is further determined whether or not the power key 40 is turned off (step S14). ) When the timer A has reached a predetermined auto power-off time or when the power key 40 is turned off by the user, all the processes are terminated. If neither is true, the step returns to S12 and the motor short circuit detection process is repeatedly executed.
[0030]
In the flowchart of FIG. 4, the motor short-circuit detection process is executed after the power key 40 is turned on until the start key 41 is turned on, and after the cool-down operation in step S9 is completed. However, in addition to this, the motor short-circuit detection process can be performed in a period in which the motor 27 is controlled to stop. For example, after cool-down operation, so-called soft wrinkle operation may be performed to prevent clothes from wrinkling. Generally, in soft wrinkle operation, drum rotation for a relatively short time (for example, about 5 seconds) and drum stop for a long time (for example, about 55 seconds) are alternately performed. Since the motor 27 is controlled to stop even during the drum stop period of the soft wrinkle operation, a motor short-circuit detection process described in detail later can be executed.
[0031]
Next, the motor short circuit detection process in steps S3 and S12 will be described with reference to the flowchart of FIG. After the start of processing, first, the timer B for motor short circuit detection is started (step S20). When the timer B reaches 5 seconds (step S21), the timer B is reset and the timer starts again (step S21). Step S22). At the same time, the motor rotation number counter is reset to start counting (step S23). The motor rotation number counter is a counter that receives one pulse signal generated from the rotation number detection circuit 63 every time the motor 27 makes one rotation and counts this.
[0032]
When the timer B for motor short circuit detection reaches 5 seconds (step S24), the count value of the motor rotation number counter is compared with a predetermined motor rotation number determination threshold value (70 in this case) (step S25). . If the value of the motor rotation number counter is larger, the process proceeds to step S26, and error processing described later is executed.
[0033]
As described above, since the motor short-circuit detection process is performed during a period in which the motor 27 is controlled to be turned off, the motor 27 is normally in a stopped state. Further, when the motor short circuit detection process is performed immediately after the cool-down operation time has ended (or immediately after the control of the motor 27 is shifted from rotation to stop in the soft wrinkle operation), the motor 27 is in the vicinity of the steady rotation speed at the start of the process. Although it is rotating, the rotation speed is lowered during the elapse of 5 seconds in step S21, and the rotation speed is sufficiently low in the process of step S24.
[0034]
Therefore, when the count value of the motor rotation number is large in step S25, it can be determined that the state is different from the state that can be normally assumed, that is, the motor 27 is rotating abnormally. As described above, the motor rotation speed determination threshold value in step S25 is determined according to the degree to which the rotation speed of the motor 27 is decelerated during the standby period of 5 seconds or the drum 27 is intentionally turned by the user. The rotational speed when rotating is taken into consideration, and is set to an appropriate value in advance.
[0035]
Next, the error processing in step S26 will be described with reference to the flowchart of FIG. In error processing, the drive control of the motor 27 is stopped by setting the motor ON signal to zero (step S30), and the current supplied to the heaters 25a and 25b is cut off to stop heating (step S31). . In the motor short circuit detection as described above, since the motor 27 is controlled to be always turned off, the process of step S30 has no meaning in practice, but is common to various other abnormality detections (not described). The process of step S30 is executed as an error processing routine.
[0036]
Furthermore, the LED lighting circuit 62 is driven, and each of the LEDs of “10 minutes remaining”, “Drying 1” to “Drying 2”, “Weaker switching weak”, and “Standard drying course” is displayed as a display operation when an abnormality occurs. Is also blinked (step S32). Then, the auto power off time until the auto power off circuit (APO) 67 is activated is set to a short value (step S33). For example, when the drying operation is completed normally, the auto power off time is set to 5 minutes, and when an abnormality occurs, the auto power off time is set to about 1 minute. In step S14 of FIG. 4, the power is shut off when the auto power off time has elapsed. Therefore, when the error generation process is performed, even if the user is not around the clothes dryer and the power key 40 is not turned off, the power is quickly shut down by the auto power off process.
[0037]
Further, in the processing of FIG. 6, the user is notified of the abnormality by blinking the LED, but further, the buzzer circuit 64 may be driven to alert the user with the warning sound of the electronic buzzer 45. good.
[0038]
Note that the above-described embodiment is an example, and it is obvious that modifications and corrections can be made as appropriate within the scope of the present invention.
[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 an appearance of an operation panel of the clothes dryer.
FIG. 3 is an electrical configuration diagram of the clothes dryer.
FIG. 4 is a flowchart showing the entire processing of the clothes dryer.
FIG. 5 is a flowchart showing a control operation of a motor short circuit detection process of the clothes dryer.
FIG. 6 is a flowchart showing a control operation of error processing of the clothes dryer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 13 ... Drum 27 ... Motor 34 ... Rotation sensor 50 ... Microcomputer 62 ... LED lighting circuit 63 ... Rotation speed detection circuit 64 ... Buzzer circuit 68 ... Load drive circuit

Claims (3)

In a clothes dryer having a rotating drum,
a) a motor for rotating the drum;
b) drive control means for driving and controlling the motor;
c) a rotational speed detection means for detecting the rotational speed of the motor;
d) The motor detected by the rotation speed detection means within a first predetermined time during a period in which the motor is not controlled to rotate by the drive control means until the power is turned off after the drying operation is completed. Counting means for counting the number of rotations of
e) an abnormality detection means for determining whether or not the count value of the counting means exceeds a predetermined value;
f) notification means for notifying abnormality when the count value exceeds a predetermined value;
Equipped with a,
The counting means has passed a second predetermined time for the motor speed to drop sufficiently from the vicinity of the steady speed from the time when the drive control means controls to stop the rotation after the motor is driven to rotate. A clothes dryer characterized by starting counting of the number of rotations of the motor after waiting to be performed. 2. The clothes dryer according to claim 1, wherein the predetermined value in the abnormality detection means is set to a value that cannot be reached even if the user intentionally rotates the drum . The clothes dryer according to claim 1, further comprising a power shut-off means for automatically shutting off the power immediately or after a predetermined time when an abnormality is detected by the abnormality detection means .

Images