JPH0712060A - Scroll compressor - Google Patents

Abstract

PURPOSE:To provide a scroll compressor which can prevent deformation of an end plate caused when the inside of a pressure chamber is put under high pressure even in a full load condition. CONSTITUTION:A compression chamber 24 whose volume is reduced by turning motion is formed between a fixed scroll 1 and a turning scroll 2 meshed with each other, and a bypass hole 101 is arranged in a pressure chamber 102 so as to bypass gas through a bypass valve 105. In a scroll compressor to control capacity by returning the gas to a suction pipe 82 through a bypass pipe 103 while opening and closing the bypass valve 105 by control of pressure in the pressure chamber 102, an opening and closing valve 110 is arranged in the bypass pipe 103 so as to communicate/intercept the pressure chamber 102 and the suction pipe 82 with/from each other, and a communicating passage 111 smaller than a bypass hole 105 is arranged between the pressure chamber 102 and the compression chamber 24 in the middle of compression.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor used for refrigeration, air conditioning, etc., and more particularly to a capacity control type scroll compressor in which the back surface of a fixed scroll is kept at an intermediate pressure to suppress the deformation of the scroll.

[0002]

2. Description of the Related Art FIG. 3 is a view showing a conventional example of a conventional scroll type compressor. In the figure, C indicates a scroll type compression mechanism, 1 is a fixed scroll, 2 is a revolving scroll,
3 is a rotation prevention mechanism, 4 is an electric motor, 5 is a rotating shaft, 6 is a frame, and 8 is a hermetic housing.

Further, 11 is an end plate, 12 is a spiral wound body, and 13 is
Is a discharge board, 14 is a first discharge cavity, 17 is a discharge valve, 18 is a hole, 21 is an end plate, 22 is a spiral wound body, 23 is a boss, and 24 is a closed space. 31 is a partition wall, 5
Reference numeral 1 is an inlet hole, 52 is an oil supply hole, 53 is an eccentric pin, and 54 is a drive bush. Reference numeral 61 is a chamber, and 62 is an oil drain hole. Further, 71 is an upper bearing, 72 is a lower bearing, 73 is a swivel bearing, and 74 is a thrust bearing. Reference numeral 81 is a lubricating oil, 82 is a suction pipe, and 84 is a balance weight.

On the other hand, 101 is a bypass hole, 102 is a pressure chamber, 103 is a bypass pipe, 104 is a switching valve, 105 is a bypass valve, and 106 is a retainer. The bypass pipe 103 communicates with the suction pipe 82 and the discharge pipe 83 via the switching valve 104 outside the compressor.

In such a conventional scroll compressor,
Gas compression is performed as follows. That is, the rotation of the electric motor 4 is transmitted to the orbiting scroll 2 via the rotary shaft 5, the eccentric pin 53, the drive bush 54, and the orbiting bearing 73, and the orbiting scroll 2 is revolved while being prevented from rotating by the rotation preventing mechanism 3. To do. The gas enters the housing 8 through the suction pipe 82, and the electric motor 4
After being cooled, it is sucked into the plurality of closed spaces 24 from the suction passage 15 provided in the fixed scroll 1 through the suction chamber 16. Then, as the volume of the closed space 24 decreases due to the orbiting movement of the orbiting scroll 2, the compressed space reaches the central portion while being compressed, and pushes up the discharge valve 17 from the discharge port 13 and discharges it to the first discharge cavity 14. Then, it is discharged to the outside through the hole 18. The bypass hole 101 allows the gas in the process of being compressed from the closed space 24 to be bypassed to the suction pipe 82 via the pressure chamber 102 and the bypass pipe 103 as necessary to control the capacity of the compressor.

That is, the bypass pipe 103 and the discharge pipe 83
, The pressure chamber 102 has a high discharge pressure, the bypass valve 105 provided in the pressure chamber 102 is pressed against the end plate 11, the bypass hole 101 is closed, and all the gas in the closed space 24 is compressed. Is discharged from the discharge pipe 83 to be in a full load state.

On the other hand, when the bypass pipe 103 and the suction pipe 82 are made to communicate with each other, the pressure chamber 102 has a low suction pressure, and a part of the gas in the closed space 24 pushes up the bypass valve 105 from the bypass hole 101 to press the pressure chamber 102, Bypass pipe 10
After passing through 3, the intake pipe 82 is bypassed to be in an unload state.

[0008]

The conventional scroll compressor described above has the following problems. That is,
In the full load state, the pressure chamber 102 has a high pressure, so that the end plate 11 of the fixed scroll 1 has a concave shape of ten and several μm.
Deform to some extent. Therefore, there is a possibility that the inner surface of the end plate 11 comes into contact with the tip of the vortex winding body 12 of the orbiting scroll 2 to cause a so-called galling phenomenon.

Therefore, an object of the present invention is to provide a scroll compressor capable of preventing the deformation of the end plates caused by the high pressure in the pressure chamber even in the full load state.

[0010]

In order to solve the above-mentioned problems and to achieve the object, the present invention relates to a pair of fixed scrolls and orbiting scrolls meshed with each other, and the orbiting scrolls between the fixed scrolls and the orbiting scrolls. By the revolution revolving motion of the scroll, while forming a compression chamber whose volume decreases as it moves toward the center side, on the end plate of the fixed scroll,
A bypass hole for bypassing the gas in the compression chamber during compression to the pressure chamber formed on the back surface of the end plate via the bypass valve is provided, and the bypass valve is opened and closed by the pressure control in the pressure chamber to remove the bypassed gas. In a scroll compressor whose capacity is controlled by returning to a suction pipe via a bypass pipe, an opening / closing valve that connects and disconnects the pressure chamber and the suction pipe is provided in the bypass pipe, and the compression chamber and the compression in the middle of compression are provided. A communication passage smaller than the bypass hole is provided between the chamber and the chamber.

[0011]

As a result of taking the above-mentioned means, the following effects occur. That is, when the on-off valve is closed, all the gas in the closed space is compressed and discharged from the discharge pipe, and a full load state is set. Since the closed space and the pressure chamber communicate with each other through a narrow passage, the pressure in the pressure chamber becomes an intermediate pressure that changes according to the suction pressure. Therefore, when the suction pressure decreases during the compression operation, the gas in the pressure chamber flows back into the closed space through the hole provided in the bypass valve, and the intermediate pressure also decreases. For this reason,
Even in the full load state, the pressure in the pressure chamber becomes an intermediate pressure, and the deformation of the end plate of the fixed scroll becomes small.

[0012]

1 is a vertical sectional view of a scroll compressor according to an embodiment of the present invention. FIG. 2A is a cross-sectional view showing an enlarged pressure chamber. Note that, in FIG. 1, the same functional portions as those in FIG. 3 are denoted by the same reference numerals.

A scroll compression mechanism C is arranged in the upper part of the closed housing 8 and an electric motor 4 is arranged in the lower part thereof, which are interlockingly connected to each other by a rotary shaft 5.
The scroll-type compression mechanism C is a frame in which the fixed scroll 1, the orbiting scroll 2, a rotation preventing mechanism 3 such as an Oldham link which allows the revolution of the orbiting scroll 2 but prevents its rotation, the fixed scroll 1 and the electric motor 4 are locked. 6, an upper bearing 71 and a lower bearing 72 that pivotally support the rotary shaft 5, and an orbiting bearing 73 and a thrust bearing 74 that support the orbiting scroll 2.

The fixed scroll 1 includes an end plate 11 and a spiral scroll 1.
The end plate 11 is provided with a discharge board 13 and a discharge valve 17 for opening and closing the discharge board 13. Further, a first discharge cavity 14, a suction passage 15, and a suction chamber 16 are provided. Further, a hole 18 is formed in the partition wall 31 provided on the upper portion of the end plate 11. Orbiting scroll 2
Is composed of an end plate 21, a spiral wound body 22 and a boss 23, and a drive bush 54 is axially supported in the boss 23 via a swivel bearing 73. And this drive bush 5
4 is an eccentric pin 53 protruding from the upper end of the rotary shaft 5.
Is rotatably supported. Reference numeral 84 is a balance weight attached to the drive bush 54.
A plurality of closed spaces 24 are formed by engaging the fixed scroll 1 and the orbiting scroll 2 with each other.

An inlet hole 51 is provided at the lower end of the rotary shaft 5, and an oil supply hole 52 communicates with the upper part inside. The frame 6 is provided with a chamber 61 and an oil drain hole 62. A suction pipe 82 is provided on the side wall of the housing 8.

Further, the end plate 11 of the fixed scroll is provided with a bypass hole 101 and a pressure chamber 102. further,
The partition wall 31 is provided with a bypass pipe 103,
An on-off valve 110 is connected to this bypass pipe 103. The on-off valve 110 is connected to the suction pipe 82. The pressure chamber 102 is provided with a bypass pipe 103 through a bypass hole 101.
And the bypass hole 101 is connected to the bypass valve 10
It is covered by 5, and its movement is restricted by the retainer 106. On the other hand, as shown in FIG. 2A, the bypass valve 105 is provided with a communication hole 111 having a small diameter.

The scroll compressor configured as described above operates as follows. That is, when the electric motor 4 is driven to rotate, this rotation causes the rotation shaft 5, the eccentric pin 53,
It is transmitted to the orbiting scroll 2 via the drive bush 54 and the orbiting bearing 73, and the orbiting scroll 2 revolves around the axis while being prevented from rotating by the rotation preventing mechanism 3. Gas enters the housing 8 through the suction pipe 82, cools the electric motor 4, and then is sucked into the closed space 24 from the suction passage 15 through the suction chamber 16. Then, as the volume of the closed space 24 decreases due to the orbiting movement of the orbiting scroll 2, it reaches the center while being compressed, and pushes up the discharge valve 17 from the discharge port 13 and discharges it into the first discharge cavity 14, and then. , And is discharged to the outside through the holes 18.

The lubricating oil 81 stored in the bottom of the housing 8 is sucked up from the inlet hole 51 by the centrifugal force generated by the rotation of the rotary shaft 5, passes through the oil supply hole 52, and the lower bearing 72, the eccentric pin 53, and the upper bearing 71. After lubricating the rotation prevention mechanism 3, the slewing bearing 73, the thrust bearing 74, etc.,
The oil is discharged to the bottom of the housing 8 through the chamber 61 and the oil drain hole 62.

Next, the capacity control mechanism will be described. The bypass hole 101 allows the gas in the process of compression to be bypassed from the closed space 24 to the suction pipe 82 via the pressure chamber 102 and the bypass pipe 103 as necessary, thereby controlling the capacity of the compressor. Open the on-off valve 110 to open the bypass pipe 103
And the suction pipe 82 are communicated with each other, the pressure chamber 102 has a low suction pressure, and a part of the gas in the closed space 24 pushes up the bypass valve 105 from the bypass hole 101 to cause the pressure chamber 10 to flow.
2. After being bypassed by the suction pipe 82 through the bypass pipe 103, the unloading state is established.

On the other hand, the on-off valve 110 is closed and the bypass pipe 10 is closed.
When 3 is communicated with the discharge pipe 83, the pressure chamber 102 has a high discharge pressure, the bypass valve 105 provided in the pressure chamber 102 is pressed against the end plate 11, closes the bypass hole 101, and closes the sealed space 24. All gas is compressed and discharge pipe 8
It is discharged from No. 3, and becomes a full load state. At this time, the pressure of the pressure chamber 102 becomes an intermediate pressure MP determined below.

MP = LP (V _th / V) ^k (1) where LP is the suction pressure, V _th is the amount of displacement, V is the volume of the closed space 24 communicating with the bypass hole 101, and K is the adiabatic index. is there.

That is, the intermediate pressure is determined depending on the suction pressure, and when the suction pressure is lowered during the compression operation, the pressure chamber 1 is opened from the communication hole 111 provided in the bypass valve 105.
The gas in 02 flows back into the closed space 24, and the intermediate pressure also drops.

Therefore, in the present embodiment, in the full load state, the pressure in the pressure chamber 102, which was conventionally high, becomes an intermediate pressure, and the end plate 11 of the fixed scroll 1 is made.
Can be suppressed to be small.

The present invention is not limited to the above embodiment. That is, since the communication hole 111 of the bypass valve 105 is for communicating the pressure chamber 102 and the closed space 24, for example, as shown in FIG. 2B, the bypass valve 105 of the end plate 11 of the fixed scroll 1 is provided. A thin cutout groove 112 may be provided in the valve seat portion. Further, as shown in FIG. 2C, a communication hole 113 may be provided near the bypass hole 101 of the end plate 11 of the fixed scroll 1. Furthermore, it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0025]

According to the present invention, the bypass pipe and the suction pipe are connected through the on-off valve to control the capacity,
Since the narrow passage that connects the closed space and the pressure chamber is provided, the back surface of the fixed scroll can be maintained at the intermediate pressure even in the full load state. For this reason,
The deformation of the end plate of the fixed scroll can be suppressed to a small level, and the occurrence of so-called galling between the inner surface of the end plate of the fixed scroll and the tip of the spiral scroll of the orbiting scroll is prevented, and the reliability of the scroll compressor is improved. It becomes possible to improve. In addition, a switching valve has been conventionally required, but it is an on-off valve, so the cost is reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a scroll compressor according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing the vicinity of a bypass hole of the same apparatus, in which (a) shows an example, (b) shows a modified example, and (c) shows another modified example. Fig.

FIG. 3 is a vertical sectional view showing a conventional scroll compressor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed scroll 2 ... Orbiting scroll 3 ... Rotation prevention mechanism 4 ... Electric motor 5 ... Rotating shaft 6 ... Frame 8 ... Sealed housing 11, 21 ... End plate 12, 22 ... Spiral roll 13 ... Discharge board 14 ... 1st Discharge cavity 17 ... Discharge valve 18 ... Hole 23 ... Boss 24 ... Closed space 31 ... Partition wall 51 ... Inlet hole 52 ... Oil supply hole 53 ... Eccentric pin 54 ... Drive bush 61 ... Chamber 62 ... Oil discharge hole 71 ... Upper bearing 72 ... Lower bearing 73 ... Orbiting bearing 74 ... Thrust bearing 81 ... Lubricating oil 82 ... Suction pipe 84 ... Balance weight 101 ... Bypass hole 102 ... Pressure chamber 103 ... Bypass pipe 105 ... Bypass valve 106 ... Retainer 110 ... Open / close valve 111, 113 ...
Communication hole 112 ... Notch groove

Claims (3)

[Claims] 1. A compression chamber in which a pair of fixed scrolls and an orbiting scroll are meshed with each other, and a volume of the compression chamber is reduced between the fixed scroll and the orbiting scroll by the revolution orbiting motion of the orbiting scroll. Along with the formation of the fixed scroll, the end plate of the fixed scroll is provided with a bypass hole for bypassing the gas in the compression chamber in the middle of the compression chamber to the pressure chamber formed on the back face of the end plate through a bypass valve, and by controlling the pressure in the pressure chamber. In a scroll compressor that controls the capacity by opening and closing the bypass valve and returning the bypassed gas to the suction pipe through the bypass pipe, an opening / closing valve that connects and disconnects the pressure chamber and the suction pipe to the bypass pipe. In addition, a communication passage smaller than the bypass hole is provided between the pressure chamber and the compression chamber in the middle of compression. Crawling compressor. 2. The scroll compressor according to claim 1, wherein the communication passage is provided in the bypass pipe. 3. The scroll compressor according to claim 1, wherein the communication passage is provided in an end plate of the fixed scroll.