JP5164467B2 - refrigerator - Google Patents

Description

  The present invention relates to a refrigerator.

  A conventional refrigerator is disclosed in Japanese Patent Laid-Open No. 10-103849 (Patent Document 1). This refrigerator is provided with a decompression storage chamber, and this decompression storage chamber is independent of other storage chambers and is not cooled, and is decompressed by sucking air with a vacuum pump. As a result, it is possible to store foods that do not require cooling but need to be dried and preserve moisture for a long period of time. Reduces power consumption by using a pressure sensor as a means for detecting air pressure in the decompression storage chamber, operating the vacuum pump when the detected pressure is higher than the specified pressure, and stopping the vacuum pump when the detected pressure is lower and operating intermittently. doing.

  Similarly, an example of depressurizing the storage space is disclosed in Japanese Patent Application Laid-Open No. 2004-20113 (Patent Document 2). In order to preserve food for a long period of time by storing the fresh air by controlling the air atmosphere in the food storage room to a low oxygen state, this refrigerator is independently provided with a decompression storage space in the storage room, and a vacuum pump is provided in the machine room. It is installed adjacent to the compressor. This vacuum pump discharges the air in the reduced pressure storage space through the exhaust pipe, and reduces the pressure to a predetermined pressure depending on the suction time of the vacuum pump and the opening degree of the exhaust pipe to make it a low oxygen state.

Japanese Patent Laid-Open No. 10-103849 JP 2004-20113 A

  However, the conventional example described above has the following problems.

  In Patent Document 1, the vacuum pump is controlled by the level of the pressure in the decompression storage chamber with respect to the predetermined pressure, but whether or not the predetermined pressure when the vacuum pump is turned on and the predetermined pressure when the vacuum pump is turned off is the same. The details are not clearly described, and there is a concern that the on / off repetition increases even if the vacuum pump can be intermittently operated. In addition, the specification of the pressure sensor that detects the pressure in the decompression storage chamber is not specified. In general, what is called a pressure sensor often indicates an analog output capable of being output in accordance with a sensed pressure, and such a sensor is expensive and difficult to use for a consumer product such as a refrigerator.

  Patent Document 2 is a method in which the pressure is reduced to a predetermined pressure depending on the suction time of the vacuum pump. However, when the capacity of the vacuum pump is constant, the pressure reduction speed is considered to be different depending on the volume of the vacuum storage space. When the user stores food in the vacuum storage space, the volume that can be sucked by the vacuum pump is apparently reduced as well as the difference in the original vacuum storage space volume. In other words, the vacuum storage space volume varies depending on the use situation, and it is difficult to always control to a predetermined pressure for a fixed suction time. Also, the method based on the opening degree of the exhaust pipe is considered to cause the same problem. However, Patent Document 2 does not disclose a method for solving the problem.

  An object of the present invention is to provide a decompression control method suitable for decompressing a storage room of a refrigerator.

The present invention, as described in claim 1, is a refrigerator comprising a storage chamber and a decompression means for depressurizing the storage chamber, and operates according to the degree of vacuum in the storage chamber and is higher than a predetermined pressure. has a pressure detecting means for detecting or lower, after said said pressure detecting means decompression means is operated detects that less than the predetermined pressure, by stopping the pressure reduction means after the elapse the first predetermined time after the pre-Symbol decompression means said pressure detecting means after the stop is detected that is higher than the predetermined pressure, time during which the pressure sensing means said pressure reducing means after stopping is required until it is detected that is higher than the predetermined pressure from passed a second predetermined time calculated in the refrigerator, characterized in Rukoto actuates said pressure reducing means based on. According to the present invention, the pressure can be reduced to a desired pressure without using a high sensor such as a pressure sensor. Further, when the pressure reducing means is operated each time the pressure detecting means is operated , it is necessary to operate the motor as much as that. However, there is a certain time width such as the first predetermined time or the second predetermined time. Accordingly, it is not necessary to operate the motor as much as that, so that the life of the motor can be extended. Also, fully sealed storage chamber trough Uno is impossible in reality, always leak occurs. The amount of change in leakage amount from a variety der Rukoto, pressure detection means vacuum means after stopping it is possible to longer second predetermined time longer the time until the operation.

According to the invention described in claim 2 of the present invention, in claim 1, the pressure reducing means is operated to detect that the pressure detecting means is lower than the predetermined pressure for the first predetermined time . It is in the refrigerator characterized by changing according to the time until. According to the present invention, when there is not much stored item in the storage chamber, the time from the operation of the decompression unit to the operation of the pressure detection unit is longer than the case where there is a stored item. By making the length longer, it is possible to approach the desired degree of vacuum.

According to the third aspect of the present invention, in the first or second aspect, the time until the pressure detecting unit is operated to detect that the pressure detecting unit is lower than the predetermined pressure is a third predetermined amount. In the refrigerator, the decompression means is stopped when the time is shorter than the time. According to the present invention, when evacuating, for example, when an object is clogged between the pipe connecting the storage chamber and the pump, which is a decompression means, it is determined that there is an abnormality and processing is performed. Can do.

According to a fourth aspect of the present invention, in the first or second aspect, the time until the pressure detecting means is operated and the pressure detecting means detects that the pressure is lower than the predetermined pressure is a fourth predetermined time. In the refrigerator, the decompression means is stopped when the time is longer than the time. According to the present invention, when evacuation is performed, if the amount of leakage in the storage chamber is severe, evacuation cannot be performed.

According to a fifth aspect of the present invention, in the refrigerator according to the third or fourth aspect , the decompression unit is stopped and an abnormality is notified.

According to the present invention as set forth in claim 6 , there is provided a refrigerator including a storage chamber, a vacuum pump for depressurizing the storage chamber, and a motor for driving the vacuum pump, the degree of vacuum in the storage chamber has a pressure detecting means for detecting whether higher or lower than a predetermined pressure and operates according to, after the pressure sensing means to operate the motor detects that less than the predetermined pressure, the first predetermined time after After that, the difference N0 between the initial rotational speed N0 of the motor when the vacuum pump is started and the current rotational speed N of the motor after the pressure detection means detects that the pressure is lower than the predetermined pressure. In the refrigerator, the motor is stopped when -N becomes equal to or greater than G. According to the present invention, the pressure reduction operation can be made more accurate by controlling the rotation of the motor using the deviation of the motor rotation speed after the pressure detection means is operated.

According to a seventh aspect of the present invention, in the refrigerator according to the sixth aspect , the motor is a DC motor.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the decompression control method suitable for decompressing the storage chamber of a refrigerator.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a front view of the refrigerator of the present embodiment.

  The refrigerator is constructed and arranged in the refrigerator compartment 2, the ice making compartment 3, the freezer compartment 4, and the vegetable compartment 5 from the top. The refrigerator compartment 2 and the vegetable compartment 5 are storage compartments in a refrigerated temperature zone, and the ice making compartment 3 and the freezer compartment 4 are storage compartments in a freezing temperature zone of 0 ° C. or less (for example, a temperature zone of about −20 ° C. to −18 ° C.). It is. Reference numeral 13 denotes an operation panel which is composed of a display LED 13a (not shown) and an operation switch (not shown).

  FIG. 2 is a front view of the inside of the refrigerator compartment 2 of FIG. Reference numeral 8 denotes a refrigeration room door switch that detects opening and closing of the refrigeration room door that closes the opening of the refrigeration room 2, and a low pressure room 6 that is a storage room is arranged at the lowermost stage of the refrigeration room 2. Here, the low pressure chamber refers to a chamber that can be depressurized from atmospheric pressure to less than atmospheric pressure by a depressurizing means (for example, a vacuum pump).

  FIG. 3 is a perspective view of the lowermost step portion of the refrigerator compartment 2 in FIG. 2, and FIG. 4 is a perspective view of the low pressure chamber 6. The low pressure chamber 6 has a low pressure chamber door 6a for opening / closing the food intake / outlet opening on the front surface, and a low pressure chamber door switch 9 detects opening / closing of the low pressure chamber door 6a. Reference numeral 7 denotes a vacuum pump, which is an operation / configuration in which the vacuum pump 7 and the low pressure chamber 6 are connected by a conduit 7a, and the air in the low pressure chamber 6 is sucked by the vacuum pump 7 through the conduit 7a. FIG. 5 is a diagram simply showing the connection from the vacuum pump 7 to the low pressure chamber 6. As shown in FIG. 5, a pressure switch 11 is built in the vacuum pump 7, and the pressure switch 11 is electrically connected to the low pressure chamber 6 through the conduit 7a so that the pressure in the low pressure chamber 6 can be detected.

(First embodiment)
In the above configuration, a first embodiment in which the pressure in the low pressure chamber 6 is reduced will be described below with reference to FIGS.

  FIG. 6 is a control block diagram. Reference numeral 10 is a refrigerator temperature sensor for detecting the temperature in the refrigerator compartment 2, reference numeral 12 is a microcomputer, reference numeral 13 a is a display LED incorporated in the operation panel 13, and reference numeral 7 b is a DC motor for driving the vacuum pump 7. The detection signals of the refrigerator compartment door switch 8, the low pressure compartment door switch 9, the refrigerator compartment temperature sensor 10, and the pressure switch 11 are input to the microcomputer 12, and output to the display LED 13a and the vacuum pump 7 (DC motor 7b) based on the control specifications described later. It is the structure which outputs a signal. The rotation speed signal 7c is a signal representing the motor rotation speed of the DC motor 7b, and the signal is fed back to the microcomputer 12.

  Next, the pressure reduction performance when the vacuum pump 7 is operated is shown in FIG. The abscissa indicates the operation time after the operation of the vacuum pump 7 in the atmospheric pressure state, and the ordinate indicates the pressure in the low pressure chamber 6. In this specification, the pressure value is a gauge pressure, and the unit is represented by kPa · G. Therefore, atmospheric pressure = 0 kPa · G, and a negative value at a lower pressure than that.

  When vacuum vessels having a volume of 5 L, 10 L, and 15 L were prepared and individually connected to the vacuum pump 7 and operated, according to experiments by the inventors, when the vacuum pump 7 was started to operate as shown in FIG. The pressure gradually decreased with time. Since the vacuum pumps have different volumes, that is, the amount of air to be sucked is different, the same vacuum pump 7 is used. Therefore, it is considered that the smaller the volume, the faster the pressure decreases.

  Here, a pressure reducing operation in the low pressure chamber 6 is considered. Although the volume of the low-pressure chamber 6 itself is determined, when the user stores food in the low-pressure chamber 6, the amount of air that can be sucked in the low-pressure chamber 6 is reduced, so that the substantial volume of the low-pressure chamber 6 is the same. It is. When the pressure reduction target pressure of the low pressure chamber 6 is set to −30 kPa · G, it is difficult to control only by the operation time of the vacuum pump 7. For example, when the operation time of the vacuum pump 7 is uniformly set to 60 seconds, the substantial volume in the low pressure chamber 6 may be 5 L, but if it is 15 L, it will not reach −20 kPa · G. Become.

  Therefore, pressure reduction control using the pressure switch 11 will be described. Since the pressure switch 11 uses an inexpensive one, as shown in FIG. 8, the pressure detection value is 1 when the pressure is lower than −20 kPa · G and turned on when the pressure is higher than −20 kPa · G. Use only points.

  FIG. 9 is a basic control flowchart when the pressure reducing operation is performed. The purpose of this flowchart is to determine the optimum operating time of the vacuum pump 7 by the pressure switch 11 and control the pressure reduction to the pressure reduction target pressure. Note that it is assumed that the pressure in the low pressure chamber 6 is around 0 kPa · G at the start of control (step S1).

  After step S1, in step 2, the open / close state of the refrigerator compartment door is determined. If the refrigerator compartment door is closed, the process proceeds to step 4 to operate the vacuum pump 7, and if it is open, the vacuum pump 7 is stopped. Since the operation sound is generated during the operation of the vacuum pump 7, the control is performed to stop the vacuum pump 7 so as not to be annoying when the user opens the refrigerator compartment door.

  After operating the vacuum pump 7 in step S4, c time is integrated in step S5. The time c is for counting the accumulated operation time of the vacuum pump 7. Σc is a time required from 0 kPa · G to −20 kPa · G when the pressure switch 11 operates. Next, in step S6, a D time which is a first predetermined time is calculated. D time = Σc × coefficient, that is, the longer the accumulated operation time of the vacuum pump 7, the longer the D time. Next, in step S7, the state of the pressure switch 11 is determined. When the pressure switch 11 is not operating, that is, when the pressure switch 11 is on (pressure is −20 kPa · G or more), the process returns to step S2, and when the pressure switch is operated, that is, when it is off (pressure is less than −20 kPa · G). Proceed to step S8. In other words, steps S <b> 2 to S <b> 7 derive a D time corresponding to the accumulated operation time of the vacuum pump 7 until the pressure reaches −20 kPa · G after the operation of the vacuum pump 7 starts. Note that once it is determined in step S7 that the pressure switch is OFF, the D time set at the end is not changed until the end of the flowchart.

  Next, in step S8, d time is integrated. The d time is for counting the accumulated operation time of the vacuum pump 7 after the pressure becomes less than −20 kPa · G. Next, in step S9, Σd and D time are compared. If Σd is less than D time, the process returns to step S2, and if it is equal to or longer than the first predetermined time D time, the process proceeds to step S10 and the vacuum pump 7 is stopped. This is the end (step S11).

  With the control shown in FIG. 9, it is possible to control the target pressure to be reduced regardless of the substantial volume in the low pressure chamber 6. In other words, the time (Σc) from 0 kPa · G to -20 kPa · G corresponds to the pressure reduction speed, and the time (D time) required from -20 kPa · G to -30 kPa · G is calculated from the pressure reduction speed. That is why.

  Specifically, it is considered by applying to the decompression performance shown in FIG.

<When the volume is 15L>
Σc which is the time from 0 kPa · G to −20 kPa · G = about 75 seconds Σd (= D) which is the time from -20 kPa · G to −30 kPa · G = about 85 seconds 85 seconds ÷ 75 seconds = 1.13 ... Solution (1)
<In case of 10L capacity>
As in the case of the volume 15 L, Σc = about 50 seconds and Σd = about 60 seconds.
60 seconds ÷ 50 seconds = 1.20 ... Solution (2)
<In case of volume 5L>
As in the case of the volume 15L, Σc = about 30 seconds and Σd = about 30 seconds.
30 seconds ÷ 30 seconds = 1.00 ... Solution (3)
Here, if the average of the solutions (1) to (3) is taken and the coefficient in the flowchart of FIG. 9 is set to 1.1, the target pressure (−30 kPa) is almost reduced regardless of the substantial volume in the low pressure chamber 6. -It becomes possible to control to G).

  Next, the control after the inside of the low pressure chamber 6 has reached the pressure reduction target pressure (−30 kPa · G) will be described.

  After reaching −30 kPa · G, the low pressure state is basically maintained unless the user opens the low pressure chamber door 6a. However, it is not easy to make the space between the vacuum pump 7, the conduit 7a, and the low pressure chamber 6 completely sealed, and minute air leakage occurs. If air leaks from the outside of the low pressure chamber 6 to the inside, the pressure gradually increases and then returns to 0 kPa · G.

  FIG. 10 shows an image thereof. After the vacuum pump 7 is stopped, when the air leak is large, it returns to 0 kPa · G in an early time, and when the air leak is small, the time to 0 kPa · G becomes long. The inside of the low pressure chamber 6 is depressurized for the purpose of long-term storage of stored food. When the pressure returns to around 0 kPa · G, it is necessary to operate the vacuum pump 7 again to depressurize. For this purpose, it is necessary to detect that the pressure in the low pressure chamber 6 has risen to around 0 kPa · G. In addition, since it is considered that the amount of air leakage varies depending on the degree of completion of the low pressure chamber 6 and the like, it is necessary to detect that the amount of air leakage has risen to around 0 kPa · G regardless of the amount of air leakage.

  Therefore, the pressure increase is detected in the basic control flowchart shown in FIG. This flowchart is substantially the same control as the decompression control shown in the flowchart of FIG. 9, and only the direction of pressure change is reversed. That is, the optimal operation standby time of the vacuum pump 7 is determined by the pressure switch 11 and the purpose is to detect the arrival of the vicinity of 0 kPa · G (atmospheric target pressure). At the start of control (step S12), it is assumed that the pressure in the low pressure chamber 6 is around −30 kPa · G, and the low pressure chamber door 6a remains closed.

  After step S12, e time is integrated in step S13. The e time is for counting the stop time of the vacuum pump 7. Next, in step S14, a B time which is a second predetermined time is calculated. B time = Σe × coefficient, that is, the longer the stop time of the vacuum pump 7, the longer the B time. The coefficient is, for example, if the time Σe required from -30 kPa · G to -20 kPa · G takes 5 hours, and the second predetermined time B, which is the time from -20 kPa · G to less than 0 kPa · G, is 10 hours. The coefficient is 10 hours ÷ 5 hours = 2. Therefore, the second predetermined time B changes according to the time of Σe.

  The time from -30 kPa · G to -20 kPa · G at which the pressure switch 11 operates is Σe. Next, in step S15, the state of the pressure switch 11 is determined. When the pressure switch 11 is in operation, that is, off (pressure is less than −20 kPa · G), the process returns to step S13, and when the pressure switch is not operated, that is, on (pressure is −20 kPa · G or more), step S16 is performed. Proceed to In other words, Steps S13 to S15 derive a second predetermined time B according to the stop time of the vacuum pump 7 until the pressure reaches −20 kPa · G after the stop of the vacuum pump 7.

  Next, in step S16, the time b is integrated. The time b is for counting the stop time of the vacuum pump 7 after the pressure becomes −20 kPa · G or more. Next, in step S17, Σb is compared with the second predetermined time B, and if Σb is less than the second predetermined time B, the process returns to step S13, and if it is equal to or longer than the second predetermined time B, the process ends. (Step S18). And if it is more than B time, the vacuum pump 7 will be drive | operated after that.

  With the control shown in FIG. 11, it is possible to detect that the vicinity of 0 kPa · G (atmospheric target pressure) has been reached regardless of the amount of air leakage. That is, the time (Σe) from −30 kPa · G to -20 kPa · G when the pressure switch 11 operates corresponds to the leakage speed, and the time required from −20 kPa · G to around 0 kPa · G (B time) Is calculated from the leakage speed.

  As described above, the basic control flowchart of the decompression operation shown in FIG. 9 and the basic control flowchart of the pressure rise detection shown in FIG. 11 are used to further control the entire low pressure chamber 6 by adding conditions such as opening and closing of the low pressure chamber door 6a. The summary is the control flowchart shown in FIG. Hereinafter, this flowchart will be described.

  When the operation of the refrigerator is started (step S19), the pressure value flag P for determining the pressure in the low pressure chamber 6 is set to 0 (step S20). Next, it is determined whether the pressure value flag P is 0 or -30 (step S21). Here, the pressure value flag P is a control flag for storing whether the pressure in the low pressure chamber 6 is currently in the vicinity of 0 kPa · G or −30 kPa · G, and P = 0 indicates that the pressure is 0 kPa · G. In the vicinity, P = −30 means that the pressure is assumed to be −30 kPa · G.

  If it is determined in step S21 that P = 0, it is assumed that the inside of the low pressure chamber 6 is at atmospheric pressure (near 0 kPa · G), and the process proceeds to a process in the case where the low pressure chamber 6 is depressurized (step S22). Thereafter, up to S28). When it is determined that P = −30, it is assumed that the inside of the low pressure chamber 6 is at a low pressure (−30 kPa · G), and the process proceeds to a process for detecting a pressure increase (from step S29 to S31).

  In the process for the pressure reducing operation, first, the low pressure chamber door switch 9 determines the open / closed state of the low pressure chamber door 6a (step S22). If it is determined in step S22 that the low pressure chamber door 6a is in the open state, it is not necessary to enter the pressure reducing operation of the low pressure chamber 6, time A is cleared (step S23), and the flow returns to step S22 to return to the low pressure chamber door 6a. The determination of the open / close state is continued, and the low pressure chamber door 6a is waited for to be closed. If it is determined in step S22 that the low pressure chamber door 6a is in the closed state, the process waits until time A has elapsed (step S24). Here, the A time is a standby time for determining that the low pressure chamber 6 has not been operated to some extent by the user. In the first place, the purpose of reducing the pressure of the low pressure chamber 6 is to maintain the freshness of food and to store it for a long time. For example, when the user repeatedly opens and closes the low pressure chamber door 6a within a short period of time to prepare food. It is not necessary to perform the decompression operation, and it is effective to provide the time A in order to avoid frequent operations and to maintain the life of the vacuum pump 7.

  If the time A has elapsed, Σc and Σd are cleared in step S25, and the open / close state of the low pressure chamber door 6a is determined by the low pressure chamber door switch 9 (step S26). If it is determined in step S26 that the low pressure chamber door 50 is in the open state, it is not necessary to enter the pressure reducing operation of the low pressure chamber 6, and the process returns to step S23 to wait for the low pressure chamber door 6a to be closed again.

  If it is determined in step S26 that the low pressure chamber door 6a is closed, the process proceeds to step S2, and thereafter, the same control as in the basic control flowchart of the pressure reducing operation described in FIG. The internal pressure is controlled to -30 kPa · G. However, step S27 is added. In step S27, the determination of the refrigerating room temperature sensor 10 is provided. If the temperature is high (8 ° C. or higher), the vacuum pump 7 is stopped (step S3). If the temperature is low (less than 8 ° C.), the process proceeds to step S4. This is to prevent the vacuum pump 7 from being operated at a high temperature for the purpose of improving the reliability.

  The vacuum pump 7 is stopped (step S10), the process proceeds to step S28, the pressure value flag P is set to -30, the fact that the pressure has become -30 kPa · G is stored, and the process returns to step S21.

  If it is determined in step S21 that P = −30, after Σb is cleared (step S29), the open / close state of the low pressure chamber door 6a is determined by the low pressure chamber door switch 9 (step S30).

  If it is determined in step S30 that the low pressure chamber door 6a is in the closed state, the process proceeds to step S13, and thereafter, the same control as the basic control flowchart for detecting the pressure rise described in FIG. It is detected that the pressure in the chamber 6 has risen to around 0 kPa · G.

  In step S31, the pressure value flag P is set to 0, the fact that the pressure is in the vicinity of 0 kPa · G is stored, and the process returns to step S21.

  If it is determined in step S30 that the low pressure chamber door 6a is open, the pressure in the low pressure chamber 6 is instantaneously returned to 0 kPa · G, so that P = 0 is set in step S31, and the flow returns to step S21.

  FIG. 13 is a time chart showing an example of the control flowchart operation of FIG.

With the above control, even when an inexpensive pressure switch 11 is used, the vacuum pump 7 is operated / stopped after a time calculated after the pressure switch 11 is switched on / off, so that the vacuum pump 7 is frequently operated / stopped repeatedly. The pressure reduction target pressure and the atmospheric target pressure can be controlled regardless of the substantial volume in the low pressure chamber 6 and the amount of air leakage.
(Second embodiment)
Next, an example of a response when the surroundings of the low pressure chamber 6 are abnormal will be described.

  For example, depending on the type of food stored in the low pressure chamber 6 by the user, food is clogged at the connection between the conduit 7a and the low pressure chamber 6 when the vacuum pump 7 is operated, or the inside of the conduit 7a is clogged by sucking into the conduit 7a. An abnormality such as

  For example, if a part of the vinyl bag completely closes the connection between the conduit 7a and the low pressure chamber 6, the low pressure chamber 6 will not be depressurized even if the vacuum pump 7 is operated. It is more convenient to inform the user that he / she is doing.

  When such an abnormality occurs, the amount of air that can be sucked by the vacuum pump 7 is approximately the amount inside the conduit 7a, and its volume is very small compared to the volume of the low-pressure chamber 6. When the vacuum pump 7 is operated, it is considered that the inside of the conduit 7a is depressurized to −30 kPa · G in a very short time as assumed from the graph of the depressurization performance of FIG. That is, the pressure switch 11 is also turned off (less than −20 kPa · G) in a very short time.

  Therefore, in the control flowchart shown in FIG. 14, when such an abnormality occurs, control is performed to notify the user of the abnormality.

  FIG. 14 is based on the basic control flowchart of the decompression operation of FIG. The control is started (step S32), and it is determined in step S7 that the pressure switch 11 is off (pressure minus less than −20 kPa · G). Then, in step S33, the accumulated operation time (Σc) of the vacuum pump 7 and the third time. A certain E time (for example, 5 seconds) is compared. If .SIGMA.c.gtoreq.E time, the process proceeds to step S8. If .SIGMA.c <E time, the vacuum pump 7 is stopped (step S34), the display LED 13a on the operation panel 13 is blinked (step S35), and an abnormality occurs in the user. Notify that

  Next, there is also an abnormality that is not clogged and cannot be sucked at all. For example, when the conduit 7a is cracked or a gap is formed between the main body of the low pressure chamber 6 and the low pressure chamber door 6a, the pressure cannot be reduced at all even if the vacuum pump 7 is operated. Even in such a case, it is more convenient to inform the user of the abnormality.

  Therefore, in the control flowchart shown in FIG. 15, when such an abnormality occurs, control is performed to notify the user of the abnormality. FIG. 15 shows a different determination method for step S33 in the control flowchart of FIG.

  In FIG. 15, in step S38, the accumulated operation time (Σc) of the vacuum pump 7 is compared with the F time which is a fourth predetermined time. If Σc ≧ F time, after the vacuum pump 7 is stopped (step S34), the display LED 13a of the operation panel 13 is blinked (step S35) to notify the user that an abnormality has occurred.

  For example, when the volume of the low pressure chamber 6 is 15 L, the time to reach −20 kPa · G after the operation of the vacuum pump 7 is about 75 seconds from the graph of the pressure reduction performance of FIG. The 75 seconds is a time corresponding to Σc in the control flowchart of FIG. 15. If the F time is set to 75 seconds, it can be determined whether or not the pressure reducing operation can be normally performed. Can be notified. In an actual refrigerator, it is better to set the F time to 150 seconds with a margin of, for example, twice the 75 seconds.

By the above control, even when an abnormality related to the decompression operation occurs, it can be detected and notified to the user, so that it is easy to use.
(Third embodiment)
Up to now, the method for controlling the pressure when performing the pressure reducing operation by the integrated operation time of the pressure switch 11 and the vacuum pump 7 has been described, but it is expected that the detection value of the pressure switch 11 varies. Therefore, a method for further improving the accuracy of pressure control will be described.

  First, FIG. 16 shows the relationship between the rotational speed of the DC motor 7b and the pressure during operation of the vacuum pump 7. According to the experiments by the inventors, the motor rotation speed was highest at atmospheric pressure (0 kPa · G), and the rotation speed decreased as the pressure decreased. This is presumably because the load applied to the DC motor 7b is the smallest in the atmospheric pressure state. Generally, in a DC motor, if the applied voltage is constant, the magnitude of the load and the rotational speed are in an inversely proportional relationship.

  The motor rotational speed of the DC motor 7b can be detected by the rotational speed signal 7c. In the present embodiment, pressure control with motor rotational speed information added will be described below.

  FIG. 17 is a control flowchart during the decompression operation. This flowchart is also based on the basic control flowchart of the decompression operation of FIG.

  After starting the control (step S39), when the operation of the vacuum pump 7 is started (step S4), the motor initial rotational speed N0 of the DC motor 7b obtained from the rotational speed signal 7c is stored in step S40. Note that the initial rotational speed N0 is stored only once immediately after the operation of the vacuum pump 7 is started, and thereafter N0 is held.

  Thereafter, after it is determined in step S9 that Σd ≧ D time, the motor current rotational speed N of the DC motor 7b is stored (step S41), and then the deviation between the initial rotational speed N0 and the current rotational speed N is calculated and G (Step S42). If the deviation is less than G, the process returns to Step S2, and if the deviation is G or more, the vacuum pump 7 is stopped (Step S10).

  That is, in this control flowchart, it is determined that the pressure reduction target pressure has been reached when the two conditions of the operation time of the vacuum pump 7 and the motor rotation speed are satisfied. The set value of G is set to G = 140 r / min, for example, from the graph of FIG.

  By the above method, a pressure reducing operation with higher accuracy is possible.

It is a front view of the refrigerator of one embodiment of the present invention. It is a front view of the refrigerator compartment part of the refrigerator of FIG. It is a cross-sectional perspective view of the lowest space part of the refrigerator compartment of FIG. It is a perspective view of the low pressure chamber of the refrigerator compartment of FIG. It is the figure which showed simply the connection of a vacuum pump, a conduit | pipe, and a low pressure chamber. It is a control block diagram in this embodiment. It is a figure which shows the pressure reduction performance of a vacuum pump. It is a figure which shows the detected value and ON / OFF logic of a pressure switch. It is a basic control flowchart figure at the time of pressure reduction operation. It is the image figure which showed the pressure rise by an air leak. It is a basic control flowchart figure at the time of a pressure rise. It is a control flowchart figure of the whole low pressure chamber. It is a time chart figure which shows an example of the operation | movement of FIG. It is a control flowchart figure which detects an example of abnormality occurrence at the time of pressure reduction operation. It is a control flowchart figure which detects an example of abnormality occurrence at the time of pressure reduction operation. It is the figure which showed the relationship between a pressure and the motor rotation speed of a vacuum pump. It is a control flowchart figure including the motor rotation speed information of a vacuum pump at the time of pressure reduction operation.

Explanation of symbols

2 Refrigerating room 3 Ice making room 4 Freezing room 5 Vegetable room 6 Low pressure room 6a Low pressure room door 7 Vacuum pump 7a Conduit 7b DC motor 7c Revolution signal 8 Refrigerating room door switch 9 Low pressure room door switch 10 Refrigerating room temperature sensor 11 Pressure switch 12 Microcomputer 13 Operation panel 13a Display LED

Claims (7)

A refrigerator equipped with a storage room and a decompression means for decompressing the storage room,
Pressure detecting means that operates according to the degree of vacuum in the storage chamber and detects whether the pressure is higher or lower than a predetermined pressure;
After operating the pressure reducing means and detecting that the pressure detecting means is lower than the predetermined pressure, the pressure reducing means is stopped after a first predetermined time has elapsed,
After detecting that the pressure detecting means is higher than the predetermined pressure after stopping the pressure reducing means, based on the time required to detect that the pressure detecting means is higher than the predetermined pressure after stopping the pressure reducing means. The refrigerator characterized in that the decompression means is operated after the calculated second predetermined time has elapsed.   2. The refrigerator according to claim 1, wherein the first predetermined time is changed according to a time until the pressure detecting unit is operated to detect that the pressure detecting unit is lower than the predetermined pressure. 3. The pressure reducing means according to claim 1, wherein when the time until the pressure detecting means is operated to detect that the pressure detecting means is lower than the predetermined pressure is shorter than a third predetermined time, the pressure reducing means is stopped. Refrigerator. 3. The pressure reducing means according to claim 1, wherein when the time until the pressure detecting means is operated and the pressure detecting means detects that the pressure detecting means is lower than the predetermined pressure is longer than a fourth predetermined time, the pressure reducing means is stopped. Refrigerator.   5. The refrigerator according to claim 3, wherein the decompression unit is stopped and an abnormality is notified. A refrigerator including a storage chamber, a vacuum pump for decompressing the storage chamber, and a motor for driving the vacuum pump,
Pressure detecting means that operates according to the degree of vacuum in the storage chamber and detects whether the pressure is higher or lower than a predetermined pressure;
After the motor is operated and the pressure detecting means detects that the pressure is lower than the predetermined pressure, the initial rotational speed N0 of the motor when the vacuum pump is started after the first predetermined time has elapsed and the The refrigerator is characterized in that the motor is stopped when a difference N0-N from the current rotational speed N of the motor after the pressure detecting means detects that the pressure is lower than the predetermined pressure becomes equal to or greater than a predetermined G.   The refrigerator according to claim 6, wherein the motor is a DC motor.

Images