JP3467076B2 - Refrigerator control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a refrigerator using a horizontal compressor, and more particularly to a controller for a refrigerator that has a simple structure and can accurately prevent a shortage of lubricating oil.

[0002]

2. Description of the Related Art A refrigeration cycle of a refrigerator comprises a compressor, a condenser, a pressure reducing device and an evaporator. In this compressor, an electric motor element chamber for accommodating the electric motor element and a compression element chamber for accommodating the compression element are formed side by side in a hermetically sealed container, which is disclosed in Japanese Utility Model Laid-Open No. 61-10992 and Japanese Patent Laid-Open No. 62-2849.
As shown in Japanese Patent Publication No. 76, a horizontal compressor is used which supplies lubricating oil by the pressure difference between both element chambers. This kind of compressor
When the number of rotations of the electric motor element increases, a shortage of lubricating oil may occur. That is, as the number of revolutions increases, the pressure difference between the two element chambers increases.On the one hand, the amount of oil discharged into the refrigeration cycle increases due to the rise of the lubricating oil surface, and on the other hand, the mechanism part slides due to the decrease of the lubricating oil surface. The moving surface runs out of oil and wear due to metal contact increases.

Conventionally, as a measure against a lack of lubricating oil in a compressor, a lubricating oil level detector is provided on the side of the compressor to prevent the lubricating oil from accumulating inside the compressor, as in the technique disclosed in Japanese Patent Laid-Open No. 5-203269. There is a method in which the amount is detected from the lubricating oil surface, and the rotation speed of the electric motor element is regulated based on the amount of the lubricating oil to prevent the lack of the lubricating oil when the rotation speed increases.

[0004]

However, the above-mentioned conventional method has the following drawbacks.

1) A lubricating oil level detector must be mounted outside the compressor, which increases the space occupied by the entire refrigerator.

2) If the detection method of the lubricating oil level detector is the float type, it is not possible to know the correct amount of lubricating oil when the state of the lubricating oil in the compressor is formed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a refrigerator control device which has a simple structure and accurately prevents a lack of lubricating oil.

[0008]

In order to achieve the above object, the first structure of the present invention is such that a hermetically sealed container has a motor element chamber for accommodating a motor element and a compression element chamber for accommodating a compression element. A compressor that is formed side by side and supplies lubricating oil by the pressure difference between both element chambers is used, and a condenser, a decompression device and an evaporator are added to this compressor to provide a refrigeration cycle. In the control device for a refrigerator that increases or decreases the rotation speed of the electric motor element based on the load, a control unit that restricts the rotation speed of the electric motor element based on the pressure difference is provided.

When the pressure difference exceeds a set value, the control unit may maintain the rotation speed of the electric motor element for a certain period of time and then reduce the rotation speed.

In the second configuration, the electric motor element chamber and the compression element chamber are connected by a bypass pipe, and a control unit for regulating the flow rate of the bypass pipe based on the pressure difference is provided.

[0011]

With the first configuration, the control section regulates the rotation speed of the electric motor element based on the pressure difference. Therefore, when the rotation speed of the electric motor element increases and the pressure difference increases based on the load of the refrigeration cycle, the rotation speed is regulated before the lack of lubricating oil occurs, and the rotation speed does not increase. As a result, the lack of lubricating oil does not occur, and wear due to metal contact is suppressed.

Since various load conditions occur during the operation of the refrigeration cycle, the rotation speed of the electric motor element constantly fluctuates, and the pressure difference constantly fluctuates accordingly. Therefore, the control unit frequently operates and the rotation speed frequently changes. If the set value of the pressure difference is set here and the rotational speed of the electric motor element is maintained for a certain period of time when the pressure difference exceeds the set value and then reduced, the change in the rotational speed is reduced and the control is stabilized.

In the second structure, there is a bypass pipe between the electric motor element chamber and the compression element chamber, and in this case, the control unit regulates the flow rate of the bypass pipe based on the pressure difference. To do.
Therefore, when the rotation speed of the electric motor element increases based on the load of the refrigeration cycle and the pressure difference increases, the opening degree is regulated (not fully closed) before the lack of lubricating oil occurs, and the pressure difference is reduced. . As a result, the lack of lubricating oil does not occur, and wear due to metal contact is suppressed. In this case, the number of revolutions is not regulated, so that it is possible to prevent an increase in the amount of oil discharged without changing the capacity of the compressor.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to FIGS.

As shown in FIGS. 1 and 2, the compressor 1 according to the present invention is a horizontal compressor, and mainly has a substantially cylindrical shape and has a rotary shaft placed horizontally (a hermetically sealed case). It is composed of a container 2 and a horizontal suction cup 3 attached to it. The interior of the compressor case 2 is partitioned in the axial direction by the partition plate 4 as a boundary. Compression element 5 in one compartment
Is accommodated in the other compartment, and the electric motor element 6 is accommodated in the other compartment. The compartment in which the compression element 5 is housed is the compression element chamber (A
The compartment in which the chamber; A) and the motor element 6 are housed is a motor element chamber (room B; B). The chamber A and the chamber B are communicated with each other through a through hole 7a provided in the axial direction of the rotary shaft 7. The chamber A includes a blade chamber 8, an oil pump plate 9, and a discharge cover 10.
Is provided. The oil pump plate 9 serves to circulate the lubricating oil O between the compression element 5 and the electric motor element 6. The discharge cover 10 is formed from below the opening of the through hole 7a so as to cover the front of the opening, and the upper side is open to the A chamber. A communication path for guiding the refrigerant in the chamber A to the outside of the compressor is provided on one side of the outer periphery of the cylinder 20, and a discharge pipe 11 is connected thereto, and a pipe 12 communicating with the horizontal suction cup 3 is provided on the other side of the outer periphery of the cylinder 20. Are connected. The horizontal suction cup 3 connected to the pipe 12 has a suction pipe 14 on the opposite side for sucking the refrigerant.
It is connected to the.

As a configuration shown in FIG. 1 and omitted in FIG. 2, the compression element chamber (A chamber) for accommodating the compression element 5 and the motor element chamber (B chamber) for accommodating the electric motor element 6 are
The pressure-sensitive tubes 15 and 16 are respectively inserted, and the pressure-sensitive tube 1
A low-voltage side sensor 17 or a high-voltage side sensor 18 is attached to each of 5 and 16. The outputs of the low voltage side sensor 17 and the high voltage side sensor 18 are connected to the control unit 19. The control unit 19 constitutes a control unit that regulates the rotation speed of the electric motor element 6 based on the pressure difference between the compression element 5 and the electric motor element 6.

FIG. 3 shows a refrigeration cycle of the heat pump type air conditioner. This refrigeration cycle is the compressor 1 of the present invention.
To a condenser, a decompression device and an evaporator. Specifically, the discharge pipe 11 and the suction pipe 14 of the compressor 1 are connected to the indoor heat exchanger 32 and the outdoor heat exchanger 33 via the four-way valve 31, and the indoor heat exchanger 32 and the outdoor heat exchanger 33 are connected. Are connected via an expansion valve 34. The control unit 19 is a control device that increases or decreases the rotation speed of the electric motor element based on the load of the refrigeration cycle, and includes an inverter device 35 that drives the electric motor element and the indoor fan 3.
6. The outdoor fan 37 and the expansion valve 34 can be controlled.

Next, the operation of the embodiment will be described.

FIG. 2 shows a state in which the compressor 1 is stopped. Since the lubricating oil O is contained in the compressor 1 and there is no pressure difference between the A chamber and the B chamber, the lubricating oil surface S formed by the lubricating oil O has the same height. FIG. 1 shows a state when the compressor 1 is operating. Room A and B during operation
Since there is a pressure difference with the chamber, the lubricating oil surfaces S _A and S _B formed by the lubricating oil O are different. On the other hand, looking at the flow of the refrigerant gas, the refrigerant gas compressed in the cylinder 20 passes through the discharge valve, and the electric motor element 6 is controlled for the purpose of suppressing heat generation of the electric motor element 6.
After being discharged to the side and passing through the electric motor element 6, it passes through the through hole 7a of the rotary shaft from the electric motor element 6 side to the compression element 5 side,
It reaches the other end of room B. The refrigerant gas passes through the through hole 7a of the rotary shaft 7, is regulated by the discharge cover 10 at the opening of the through hole 7a on the compression element 5 side, enters the chamber A above the discharge cover 10, and is frozen by the discharge pipe 11. Supplied to the cycle. Since the refrigerant gas flows as described above, the pressure in the chamber A is lower than that in the chamber B. The difference between the lubricating oil surfaces S _A and S _B is due to this pressure difference.

If the rotation speed of the electric motor element 6 is increased as it is, the lubricating oil surface S _A is further raised from the state shown in FIG. When the lubricating oil surface S _A exceeds or is close to the upper end of the discharge cover 10, the lubricating oil O is discharged to the refrigeration cycle together with the refrigerant gas through the discharge pipe 11. Therefore, in the case of the conventional configuration, the lubricating oil O in the compressor 1 runs short, metal contact is caused, and wear increases. To avoid this, the lubricating oil level S _A is necessary to decrease the lubricating oil level S _A before approaching the upper end of the discharge cover 10.

In the present invention, the rotation speed of the electric motor element 6 is regulated based on the pressure difference. To this end, FIG.
An experiment was conducted by incorporating a sight glass (not shown) for checking the lubricating oil surface into the compressor 1 of 1. The results are shown in FIGS. 4 and 5. When the output voltage of the low voltage side sensor 17 is V _L and the output voltage of the high voltage side sensor 18 is V _H ,
The output voltage difference between the sensors is dV = _VH - _VL . 4 showing the relationship between the height L of the output voltage difference dV and the lubricating oil level S _A, L _MAX is the height at which the lubricating oil surface S _A is in the upper end of the discharge cover 10, L ₀ is at rest The height of the lubricating oil surface S,
dV _MAX is the output voltage difference corresponding to L _MAX , dV ₀ is the output voltage difference during stop, and dVs is the control start voltage. As shown in FIG. 4, the measurement point forms a curved straight line, and based on this straight line 41, the control start voltage d that allows control to be started before the lubricating oil surface S _A approaches the upper end of the discharge cover 10.
Vs can be defined.

Further, the pressure in the chamber _A is P _A , and the pressure in the chamber B is P
_{When B} , the pressure difference dP = P _B −P _A. In FIG. 5, which shows the relationship between the output voltage difference V and the pressure difference P, dP
_MAX is the pressure difference when the lubricating oil surface S _A is at the upper end of the discharge cover 10, and dP ₀ is the pressure difference during stop. As shown in FIG. 5, the relationship between the output voltage difference dV and the d pressure difference P is linear.

In the present invention, the low-pressure sensor 17 detects the pressure P _{A in the} A chamber at the voltage V _L , and the high-pressure sensor 18 detects the pressure P _{B in the} B chamber at the voltage V _H. The control unit 19 outputs the output voltage difference dV indicating the pressure difference P.
Becomes the control start voltage dVs, the regulation of the rotation speed of the electric motor element 6 is started. As a result, the rotation speed does not increase, and the oil discharge to the refrigeration cycle does not increase. Therefore,
Since lack of lubricating oil does not occur, wear due to metal contact is suppressed.

Next, the control operation during the heating operation of the heat pump type air conditioner of FIG. 3 will be described with reference to the flow chart of FIG. First, the four-way valve 31 is switched by the heating operation start command to enable the heating operation (step 1). The output voltage of each sensor 17, 18 is detected, and the output voltage difference dV is calculated (step 2). When the output voltage difference dV is smaller than the control start voltage dVs, the normal heating operation is performed (step 3). The lubricating oil surface S _A rises as the heating operation starts. The motor element 6 of the compressor 1 depending on the load of the refrigeration cycle
When the number of revolutions of increases, the lubricating oil surface S _A further increases,
Attempts to approach the upper end of the discharge cover 10. Output voltage difference d
When V becomes larger than the control start voltage dVs, the control unit 19 performs control for reducing the load on the compressor 1 (step 4). The contents of this control are to reduce the rotation speed of the electric motor element 6 of the compressor 1, increase the throttle amount of the expansion valve 34, and increase the air flow rate of the indoor fan 36. Expansion valve 34 throttling amount and indoor fan 36
The reason for increasing the air volume is to lower the temperature of the refrigerant in the indoor heat exchanger 32 to lower the discharge pressure of the compressor 1. This control is repeated until the output voltage difference dV becomes smaller than the control start voltage dVs.

Another embodiment will be described.

The structure of the compressor and the structure of the refrigeration cycle are the same as those in FIGS. 1 to 3, and the control contents of the control unit 19 follow the flow chart of FIG. In the control of the embodiment according to the flowchart of FIG. 6, it is possible to prevent the discharge oil of the refrigeration cycle from increasing, but the rotation speed may change frequently as shown in FIG. 7 depending on the load and capacity of the refrigeration cycle. Here, a represents the number of revolutions of the compressor, b represents a change in the output voltage difference, TA is a period during which the number of revolutions is regulated, TB is a period during normal operation, and TC is a period during which the load of the refrigeration cycle is high. , TD indicates a period during which the load is reduced.

The present embodiment eliminates this and stabilizes the rotation speed so that it does not change frequently. That is, the rotation speed is maintained for a certain period of time and then reduced. For this purpose, the control unit 19 uses the variable tr for time counting,
When the output voltage difference dV becomes larger than the control start voltage dVs with the hold setting time ts, the rotation speed at that time is maintained and the time count variable tr is counted from zero. When the variable tr reaches the hold setting time ts, the rotation speed is reduced.

This control is performed according to the flow chart of FIG. Steps 1 to 3 in FIG. 9 are almost the same as steps 1 to 3 in FIG. 6, and step 4 ′ is a step 4 in which a wait for the hold setting time ts is inserted. As a result of the control according to the flow chart of FIG. 9, as shown in FIG. 8, the rotation speed is reduced every hold setting time ts within the period TA, and the control is stable because there is no frequent change.

Next, an embodiment based on the second structure will be described.

As shown in FIG. 10, the compressor 1 is similar to the compressor 1 shown in FIGS. 1 and 2 in that the compressor case (closed container) 2, the horizontal suction cup 3, the partition plate 4,
Compression element 5, electric motor element 6, rotary shaft 7, blade chamber 8,
Oil pump plate 9, discharge cover 10, discharge pipe 11,
The pipe 12, the suction pipe 14, the pressure sensitive tubes 15 and 16, the low pressure side sensor 17, the high pressure side sensor 18, and the control unit 1.
9 and there is no pressure difference between the A chamber and the B chamber during stop, so that the lubricating oil surface S of the same height is formed as in the case of FIG. 2, and in the case of FIG. 1 during operation. Similarly to the above, the refrigerant gas flows to form the lubricating oil surfaces S _A and S _B. The difference is that a bypass pipe 91 is provided between the chamber A ( compression element 5) and the chamber B ( motor element 6). The bypass pipe 91 is provided with a control valve 92 capable of adjusting the opening degree, and the control unit 19 controls the opening degree of the control valve 92. The refrigeration cycle of FIG. 11 has a four-way valve 31, an indoor heat exchanger 32, an outdoor heat exchanger 33, an expansion valve 34, an inverter device 35, an indoor fan 36, and an outdoor fan 37, which are similar to those of the refrigeration cycle of FIG. The difference is that the control unit 19 controls the control valve 9 of the bypass pipe 91 of the compressor 1.
2 is to control the opening degree. It should be noted that this control is performed independently of the rotation speed regulation control in the above-described embodiment.

Now, in the configuration of FIG. 10 and FIG.
When the operation is started, the lubricating oil surface S _A rises. When the rotation speed of the electric motor element 6 of the compressor 1 increases due to the load of the refrigeration cycle, the lubricating oil surface S _A further rises, and the discharge cover 1
I try to get closer to the top of 0. When the output voltage difference dV between the output voltages of the sensors 17 and 18 becomes larger than the control start voltage dVs, the control unit 19 performs control for reducing the load on the compressor 1. The content of this control is to control the opening of the control valve 92 according to the pressure difference, as shown in FIG. Control valve 92 which is fully closed during normal operation
The refrigerant gas from the chamber B is opened by opening the bypass pipe 91.
Through room A. Therefore, the pressure difference is reduced.
As a result, the lack of lubricating oil does not occur, and wear due to metal contact is suppressed. In this case, the number of revolutions is not regulated, so that it is possible to prevent an increase in the amount of oil discharged without changing the capacity of the compressor.

The following embodiment uses a pressure difference sensor which directly detects the pressure difference.

As shown in FIG. 13, the compressor 1 is similar to the compressor 1 shown in FIGS. 1 and 2 in that the compressor case (closed container) 2, the horizontal suction cup 3, the partition plate 4,
Compression element 5, electric motor element 6, rotary shaft 7, blade chamber 8,
Oil pump plate 9, discharge cover 10, discharge pipe 11,
Although the pipe 12, the suction pipe 14, and the control unit 19 are included, the pressure sensitive pipes 15 and 16, the low-pressure side sensor 17, and the high-pressure side sensor 18 are not provided, and instead, the chamber A ( compression element 5) is used. ) And chamber B ( motor element 6) between the pressure difference sensor 93
Is provided.

The pressure difference sensor 93 is embedded in a through hole 94 penetrating the upper side (at least above the discharge cover 10) of the case 2 of the cylinder 20, and one side receives the pressure of the A chamber,
The other side receives the pressure in the B chamber and detects the pressure difference. An output line 95 of the pressure difference sensor 93 is drawn out through a thin tube 96 inserted in the compressor case 2. 14
6 is an enlarged view of a pressure difference sensor portion, which is a pressure difference sensor 93,
Through hole 94, output wire 95, thin tube 96, compressor case 2,
The partition plate 4, the cylinder 97 forming the blade chamber 8, the pipe 7 forming the shaft, the main bearing 98, the sub bearing 99, and the discharge cover 10 are shown.

As shown in FIG. 15, the pressure difference sensor includes a silicon substrate 15 having a diffusion resistance layer 152 on a pedestal 151.
3 is joined to form a silicon diaphragm 154, and a cylindrical main body case 155 that houses these is formed.
Small holes 156 and 157 communicating with both sides of the silicon diaphragm 154 are provided at both ends of the. Body case 155
A seal member 158 is provided between the outer periphery of the through hole 94 and the through hole 94, and collars 159 are fitted from both sides of the through hole 94 and fixed by adhesion or the like.

Direct detection of the pressure difference by the pressure difference sensor can be used for any of the controls of the three compressors 1 described above. In this case, since the sensor is housed inside the compressor 1, space is saved. Further, as compared with the case where the pressure difference is calculated after detecting the two pressures, the calculation is unnecessary.
The pressure difference sensor need not be of the diaphragm type as in this embodiment, and may be any one that detects the pressure difference between the A chamber and the B chamber.

[0037]

The present invention exhibits the following excellent effects.

(1) In the invention of claim 1, since the rotation speed of the electric motor element is regulated based on the pressure difference, it is possible to accurately prevent the lack of lubricating oil with a simple structure.
This will improve the reliability of the refrigeration cycle.

(2) In the second aspect of the invention, the control with high stability is realized by maintaining the rotation speed for a certain period of time.

(3) In the third aspect of the invention, since the pressure difference is alleviated by bypassing, not only can the lubricating oil shortage be accurately prevented with a simple structure, but also compression It can be performed without changing the ability of the machine.

[Brief description of drawings]

FIG. 1 is a sectional view of a compressor according to a first embodiment of the present invention during operation.

2 is a cross-sectional view of the compressor of FIG. 1 during a stop.

FIG. 3 is a block diagram of a refrigeration cycle showing an embodiment of the first invention of the present invention.

FIG. 4 is a characteristic diagram showing the relationship between the output voltage difference and the height of the lubricating oil surface in the compressor.

FIG. 5 is a characteristic diagram showing a relationship between an output voltage difference and a pressure difference in the compressor.

FIG. 6 is a flow chart showing an operation during a heating operation of the heat pump type air conditioner according to the first embodiment of the present invention.

FIG. 7 is a control timing diagram according to the first embodiment of the present invention.

FIG. 8 is a control timing diagram according to another embodiment of the first aspect of the present invention.

FIG. 9 is a flow chart showing an operation during heating operation of the heat pump type air conditioner according to another embodiment of the first aspect of the present invention.

FIG. 10 is a sectional view of the compressor according to the second embodiment of the present invention during operation.

FIG. 11 is a block diagram of a refrigeration cycle showing an embodiment of the second invention of the present invention.

FIG. 12 is a control diagram of a control valve opening degree according to an output voltage difference.

FIG. 13 is a sectional view of the compressor during operation showing another embodiment common to the first and second inventions.

FIG. 14 is a partially enlarged view of FIG.

FIG. 15 is a cross-sectional view of a pressure difference sensor.

[Explanation of symbols]

2 closed container 5 compression elements 6 Electric motor elements 17 Low pressure side sensor 18 High voltage side sensor 19 Control unit A compression element room (A room) B Electric motor element room (Room B)

Claims (3)

(57) [Claims] 1. A compressor in which an electric motor element chamber for accommodating an electric motor element and a compression element chamber for accommodating a compression element are formed side by side in a sealed container and a lubricating oil is supplied by a pressure difference between the element chambers is used. In a refrigerator control device that is provided in a refrigerator that constitutes a refrigeration cycle by adding a condenser, a pressure reducing device, and an evaporator to this compressor, and that increases or decreases the rotation speed of the electric motor element based on the load of the refrigeration cycle. A control device for a refrigerator, comprising: a control unit that regulates a rotation speed of the electric motor element based on the pressure difference. 2. The control of the refrigerator according to claim 1, wherein when the pressure difference exceeds a set value, the control unit reduces the rotation speed of the electric motor element after maintaining the rotation speed for a certain period of time. apparatus. 3. A compressor is provided in which a motor element chamber for accommodating an electric motor element and a compression element chamber for accommodating a compression element are formed side by side in a hermetic container, and a lubricating oil is supplied by a pressure difference between the element chambers. In a refrigerator control device that is provided in a refrigerator that constitutes a refrigeration cycle by adding a condenser, a pressure reducing device, and an evaporator to this compressor, and that increases or decreases the rotation speed of the electric motor element based on the load of the refrigeration cycle, , The above motor element
The chamber and the compression element chamber connected by a bypass pipe, the control device of the refrigerator, characterized in that it comprises a control unit for regulating the flow rate of the bypass pipe on the basis of the pressure difference.