JPS622158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary hermetic compressor in which two compression mechanisms are arranged in parallel.

Conventionally, two compressors have been operated in parallel or on one side to control capacity, and two compression mechanisms have been installed in the same sealed container to achieve the same type of operation as the above-mentioned parallel and one-sided operation. A two-compressor system is being considered in which the capacity is controlled by operating the compressor. However, it was a problem because of the large vibration and noise.

The reason why vibration and noise occur in a rotary hermetic compressor is as follows. In this type of compressor, the gas inside the cylinder is compressed as the eccentrically rotating piston rotates, but when the compressed gas is released at a predetermined rotational position, the internal pressure of the cylinder drops rapidly. This change in internal pressure acts on the eccentric piston, resulting in torque fluctuations around the piston shaft. This torque fluctuation is transmitted to the sealed container via bearings and the like, causing vibration and noise. Specifically, the vibration is caused by the resultant force of the torque fluctuation, the electromagnetic force fluctuation accompanying the shaft rotational speed fluctuation of the electric mechanism that rotates the shaft, and the inertial force fluctuation. When the compressors are operated in parallel, the torque fluctuations overlap and the rotational vibration energy is doubled, which increases vibration propagation to the closed container and further increases noise dissipation.

In addition, as a rotary compressor designed to suppress such vibration and noise, a rotary compressor has been proposed in which two compression mechanisms are provided and the eccentric portions of the pistons are shifted by 180 degrees (Utility Model Opening in 1973). Publication No. 109207). According to this, a vibration suppressing effect can be obtained to some extent.

However, since both compression mechanisms rotate in the same direction, even if the eccentric portions are deviated by 180 degrees, the torque fluctuation forces of each compression mechanism overlap in the same direction, resulting in increased vibration and noise.

An object of the present invention is to suppress vibrations of a closed container due to torque fluctuations generated in a piston due to compression operation, and to reduce noise.

The hermetic compressor of the present invention includes a hermetic container, a cylinder, an eccentric piston rotating within the cylinder, and a partition vane, each arranged coaxially in parallel with each other and housed in the hermetic container, and in the direction of rotation of the piston. a pair of compression mechanisms with opposite sides to each other, a communication passage that communicates between the spaces in the cylinders of the pair of compression mechanisms in a region near the discharge hole, a communication passage control valve that opens and closes the roller communication passage, and each of the compression mechanisms. a piston position detection mechanism that detects the position of each of the pistons; and a communication control system when the positional relationship in which the rotation angles of both pistons are the same in opposite directions is broken in response to detection signals from these piston position detection mechanisms. It is equipped with a control valve control device that opens and operates the valve.

According to the configuration of this invention, since a pair of compression mechanisms with opposite rotational directions are installed coaxially in the same sealed container, the resultant force of each force that causes vibrations occurs around the shaft of each compression mechanism. However, the polarity is completely reversed and is transmitted to the sealed container. Therefore, the vibrations generated in the closed container from both compression mechanisms cancel each other out, resulting in low vibration and low noise. The resultant force of the forces that cause the vibration is the resultant force of the force due to the gas pressure fluctuation in the cylinder, the electromagnetic force fluctuation due to the shaft rotational speed fluctuation, and the inertial force fluctuation.

Additionally, if there is a difference in the rotation speeds of both compression mechanisms due to uneven loads on each compression mechanism, the vibration suppression effect due to the above-mentioned cancellation will be reduced, but as shown below, the rotation speeds must always match each other. can get. That is, when the rotational positions of the pistons of both compression mechanisms deviate, this is detected by the piston position detection signal and the communication passage control valve opens. Therefore, the pressure is instantly balanced so that there is no pressure difference in the cylinder interiors of both compression mechanisms. As a result, the load torque fluctuations become equal, the rotational speed becomes equal, and the positional relationship between both pistons gradually becomes equal, so that a complete vibration canceling effect can be obtained again. In this way, vibration suppression effects can always be obtained through vibration cancellation.

An embodiment of the invention is shown in the drawings. In the figure, 1 is a sealed container, and two electric mechanisms 26, 25 are configured by stators 2, 3 press-fitted into the container, and rotors 4, 5 fixed to shafts 6, 7 by shrink fitting, respectively. has been done. 8,9 is 2
Each compression mechanism of the table is shown. Of these compression mechanisms 8 and 9, the compression mechanism 8 is composed of a cylinder frame 10, a piston 12, and a partition wall 16. The cylinder inner chamber 18 is airtightly isolated from the tank chamber 24 by the bearing 14 and the partition wall 16, and is partitioned into a high pressure chamber and a low pressure chamber by a partition vane 20 which is pressed against the piston 12 by a spring 22. ing. The other compression mechanism 9 is also configured similarly to the compression mechanism 8. That is, the cylinder interior chamber 17 is airtightly isolated from the tank interior chamber 23 by the cylinder frame 11, piston 13, partition vane 19, and partition wall 16, and is partitioned into a high pressure chamber and a low pressure chamber. . The cylinder inner chamber 17 and the cylinder inner chamber 18 are configured to be separated as refrigerant passages. In the compression mechanism 8, the refrigerant is sucked through a suction pipe (not shown) and flows into the cylinder inner chamber 18, and its pressure increases as the piston 12 rotates due to the driving force of the electric mechanism 26. The refrigerant whose pressure has increased pushes open the discharge valve 28, is ejected into the tank interior 24, and further passes through the refrigerant passage of the electric mechanism 26 toward the discharge pipe 30. The flow path of the refrigerant in the other compression mechanism 9 is such that refrigerant is sucked in from a suction pipe independent of the suction pipe, flows into the cylinder inner chamber 17, and its pressure increases due to the rotation of the piston 13 by the driving force of the electric mechanism 25. Then, the discharge valve 27 is pushed open to reach the tank inner chamber 23 and to the discharge pipe 29. The lubrication means of the compression mechanisms 8, 9 are suitably constructed independently. The cylinder inner chamber 17 and the cylinder inner chamber 18 are defined by the partition wall 1 between the cylinder inner chamber high pressure side regions including the respective discharge holes 31 and 32.
They communicate through a communication path 33 provided at 6. This communication path 33 is connected to a magnetic member 34 that is set to be slidable.
The communication passage control valve 36 is configured to be closed by a communication passage control valve 36 consisting of a coil 36' that attracts the magnetic member 34, and a coil 36' that attracts the magnetic member 34. Furthermore, piston position detection mechanisms 38 and 39 which can be interlocked with the partition vanes 20 and 19 are provided. This piston position detection mechanism 38, 39
The permanent magnet members are fixed to partition vanes 20 and 19, and coils for detecting changes in the magnetic field of the permanent magnet members are arranged in cylinder frames 10 and 11. Furthermore, the detection signals from the piston position detection mechanisms 38 and 39 are transmitted to the terminal terminal 4.
0 and 41, input it to the comparator circuit 42 to create a comparison signal, guide it to the energization control circuit 43, control the current from the drive voltage source 44 according to the comparison signal, and apply it to the terminal terminal 37. , and is configured to control the communication passage control valve 36. Further, the electric mechanism 2 is arranged so that the pistons 12 and 13 of the compression mechanisms 8 and 9 rotate in opposite directions.
6 and 25 are designed and installed.

Next, the operation of this hermetic compressor will be explained.
First, when the two compression mechanisms 8 and 9 are rotating together, the pressure of the refrigerant flowing into the respective cylinder inner chambers 17 and 18 increases due to the compression action of the pistons 12 and 13, and the pressure remains constant. After that, the discharge valves 27 and 28 are opened and the pressure is discharged, and when the top dead center reaches the vicinity of the partition vane 19 and 20 points, the pressure suddenly decreases to almost the suction pressure. Correspondingly to the pressure changes in this series of processes, the pressure of the refrigerant acts on the eccentric pistons 12 and 13, resulting in a kind of load torque fluctuation, and at the same time the torque of the electric mechanisms 25 and 26. It can also cause fluctuations. This causes primary rotational vibration around the shaft of the compressor as in a conventional single compressor. In addition to this, rotational vibrations due to torque fluctuations of the secondary component of the rotational speed and further rotational vibrations due to electromagnetic torque fluctuations twice the power supply frequency occur simultaneously. Therefore, for example, if two conventional compressors are used in parallel for multi-air conditioning using a capacity control system, the rotational vibration energy of the compressor will be doubled, which will cause vibrations to the board and outer frame that fixes the compressor. This is a problem because the propagation becomes large and the noise dissipation correspondingly becomes very large. However, in the case of the compressor of this embodiment, since the compression mechanisms 8 and 9 are set to rotate in opposite directions, the load torque fluctuations caused by the respective refrigerant pressures cancel each other out and become small to the extent close to zero. Further, since the torque fluctuation of the second-order component of the rotational speed and the electromagnetic torque fluctuation are also in opposite phase, the combined fluctuation thereof is also extremely small. As a result, vibration and noise are significantly reduced.

This will be explained with reference to FIGS. 2 to 4. The force acting on the compression mechanism 9 in FIG. 1 is as shown in FIG. 2 in the θ direction around the shaft 7. Curve A is the fluctuating force of gas pressure, curve B is the fluctuating force of electromagnetic force due to the fluctuation of the rotation speed of shaft 7, and curve C is
is the fluctuating force of the inertial force, and the resultant force is curve D (note that one revolution of the shaft 7 is 360°).

On the other hand, the force acting on the compression mechanism 8 is because the rotational direction θ' of the shaft 6 is opposite to that of the compression mechanism 9.
As shown in FIG. 3, in the θ direction around the shaft 6, a force that is completely opposite in positive and negative to the acting force from the compressor 9 acts. Curves A' to D' are curves A to D in Figure 2.
Shows the power corresponding to

Therefore, the vibration excited in the closed container 1 is
As shown in FIG. 4, the acting force from the compression mechanism 9 (curve E) and the acting force from the compression mechanism 8 (curve F)
This occurs because the positive and negative polarities are inversely related to each other around the axes of the shafts 6 and 7.
In this case, the magnitude of the gas pressure fluctuation force acting on both compression mechanisms 8, 9 is large, and each compression mechanism 8,
When the rotational speeds of the compressors 9 and 9 are equal, the acting forces E and F completely cancel each other out, and as a result, the vibration of the compressor follows the curve G.
As shown in , the noise is significantly reduced.

However, due to differences in the load conditions of the refrigeration cycle, a difference appears in the refrigerant pressure of the two compression mechanisms 8 and 9, and a difference in the rotational speed of the compression mechanisms 8 and 9. With respect to load torque fluctuations, there may be cases where the offsetting effect becomes worse and even becomes larger. In contrast, the refrigerant pressure on the high pressure side of each cylinder inner chamber 17, 18 is
If the pistons 2 and 13 are always kept equal until the end of the discharge process, the pistons 12 and 13, respectively.
It is possible to maintain the load torque due to the pressure applied to the two in opposite phases and in a substantially equal state. As a result,
Since the rotation speeds are approximately equal and the rotation speeds are close to synchronous, the resulting load torque fluctuations have a large canceling effect and can be significantly reduced.

In this embodiment, each cylinder inner chamber 1
Since the positional relationship of the pistons 12 and 13 is different while there is a pressure difference between the high-pressure side regions of the partition vanes 1 and 18,
A displacement difference of 9 and 20 occurs, and furthermore, the detection signals of the respective piston position detection mechanisms 38 and 39 and the comparison signal of the comparison circuit 42 are different, and correspondingly,
The current flowing through the current flowing control circuit 43 is determined. Further, in accordance with this drive current, the communication passage 33 is controlled to open by the communication passage control valve 36, and the pressure is instantly balanced so that there is no pressure difference between the respective cylinder inner chambers 17, 18. As a result, the load torque fluctuations become equal, so that the rotational speeds become equal and at the same time, the positional relationship between the pistons 12 and 13 gradually becomes equal. As a result, each piston 1
The load torque fluctuations due to the refrigerant pressure applied to the refrigerant pressures 2 and 13 are approximately equal in magnitude and have opposite phases, so that the combined load torque fluctuations are significantly reduced. Correspondingly, the secondary torque fluctuation components and electromagnetic torque fluctuations are also approximately equal in magnitude,
Since the phases are opposite, the combined load torque fluctuation also becomes very small. Further, since the communication path changes in each cylinder inner chamber 17, 18 according to the pressure difference on the high pressure side, it becomes possible to suppress a decrease in volumetric efficiency as much as possible.

On the other hand, when the multi-refrigeration cycle is stopped and only one of the refrigeration cycles is operated, it is necessary to stop one of the compression mechanisms 8 and 9 accordingly. In this case, it is necessary to block the communication passage 33 to stop the flow of refrigerant between the respective cylinder inner chambers 17 and 18. In this embodiment, one compression mechanism 8
When the compression mechanism 8 stops, the detection signal of the piston position detection mechanism 38 corresponding to the stopped compression mechanism 8 becomes zero, and the energization control circuit 43 is configured so that the output of the energization control circuit 43 in this case also becomes zero. . The communication passage control valve 36 is then turned OFF, and the communication passage 33 is designed to be closed. Therefore, there is no movement of refrigerant from the compressor mechanism 9 in operation to the compressor mechanism 8 in a stopped state, and the compressor is operated in the same manner as a conventional compressor alone. Note that the same applies when only the compression mechanism 8 is operated. Therefore,
Although the load torque fluctuation for one compressor occurs, the rotational vibration becomes small because the inertia term of the entire compressor is large enough to correspond to that for two compressors. As a result, the vibration of the system and the corresponding noise can also be reduced.

As described above, in the hermetic compressor of the present invention, a pair of compression mechanisms with opposite rotational directions are arranged coaxially and installed in the same closed container, so vibrations generated around the shafts of each compression mechanism are The resultant force of each of the causes is transmitted to the sealed container with completely opposite polarity. Therefore, the vibrations generated in the closed container from both compression mechanisms cancel each other out, resulting in low vibration and low noise. The resultant force of the forces that cause the vibration is the resultant force of the force due to the gas pressure fluctuation in the cylinder, the electromagnetic force fluctuation due to the shaft rotational speed fluctuation, and the inertial force fluctuation.

Additionally, if there is a difference in the rotation speeds of both compression mechanisms due to uneven loads on each compression mechanism, the vibration suppression effect due to the above-mentioned cancellation will be reduced, but as shown below, the rotation speeds must always match each other. can get. That is, when the rotational positions of the pistons of both compression mechanisms deviate, this is detected by the piston position detection signal and the communication passage control valve opens. Therefore, the pressure is instantly balanced so that there is no pressure difference in the cylinder interiors of both compression mechanisms. As a result, the load torque fluctuations become equal, so the rotational speed becomes equal, and the positional relationship between both pistons gradually becomes equal, again achieving a complete vibration canceling effect. In this way, there is an effect that a vibration suppressing effect can always be obtained by vibration cancellation.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of one embodiment of the present invention, Fig. 2 is an explanatory diagram of the calculated value of the force acting on one compression mechanism, and Fig. 3 is an illustration of the calculated value of the force acting on the other compression mechanism. The explanatory diagram, FIG. 4, is also an explanatory diagram of vibrations excited in the closed container. 1... Airtight container, 8, 9... Compression mechanism, 10,
11...Cylinder, 12,13...Piston, 2
5, 26...Electric mechanism, 33...Communication path, 36...
...Communication passage control valve, 38, 39...Piston position detection mechanism, 42...Comparison circuit, 43...Electrification control circuit.

Claims (1)

[Scope of Claims] 1. Comprised of a sealed container, a cylinder, an eccentric piston rotating within the cylinder, and a partition vane, each of which is arranged coaxially in parallel and housed in the sealed container, and the rotational directions of the pistons are mutually aligned. a pair of opposite compression mechanisms; a communication passage that communicates between the spaces in the cylinders of the pair of compression mechanisms in a region near the discharge hole; a communication passage control valve that opens and closes the communication passage; a piston position detection mechanism that detects the position of each piston, and a communication passage control valve that detects the positional relationship in which the rotation angles of both pistons are opposite to each other and have the same magnitude in response to detection signals from these piston position detection mechanisms. A hermetic compressor equipped with a control valve control device that opens and operates the compressor. 2. The communication path control valve is composed of an electromagnet, and the piston position detection mechanism is composed of a permanent magnet member that communicates with the partition vane of each compression mechanism and a coil that detects a change in the magnetic field of this permanent magnet member, and The seal according to claim 1, wherein the valve control device comprises a comparison circuit that compares the outputs of both the piston position detection mechanisms, and an energization control circuit that energizes the control valve control device in accordance with the output of the comparison circuit. mold compressor.