JPS58160583A - Scroll type fluidic machine - Google Patents

Abstract

PURPOSE:To prevent overpressure in a back pressure chamber at transient operational time of a compressor and ensure supply of oil to slide contact surfaces, by communicating the back pressure chamber in the back part of a turning scroll to a space in an enclosed vessel through a communication hole equipped with a check valve automatically opened and closed by a pressure difference. CONSTITUTION:A communication hole 17 communicated to a space in an enclosed vessel from a back pressure chamber 12 is provided to a frame 4, and a valve body 18 prepared by a spring material is fixed to an outlet part by a fixing bolt 19. The body 18 is easily operated by a difference between pressures before and after the valve. Then under start, stop and defrost conditions, pressure in the chamber 12 tends to rise higher during a short time due to a difference between volumes of the chamber 12 and the vessel space, here the valve 18 provided to the frame 4 is suitably operated, and the pressure in the chamber 12 can be prevented from becoming a level above the pressure in the vessel. If the pressure is equalized, capability of an eccentric pump of a main shaft can supply sufficient amount of lubricating oil to each bearing or the like and smoothly slide the bearing or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a completely hermetic scroll type fluid machine used for refrigeration and air conditioning, and is particularly suitable for a scroll compressor that employs a method in which an orbiting scroll is pressed against a fixed scroll by self-pressure. be.

A conventional scroll compressor connects a compression mechanism section consisting of a fixed scroll 2, an orbiting scroll 3, and an anti-rotation member 7 to an electric element 5 via a frame 4 and a drive shaft 6, and connects them together with lubricating oil 13. is housed in a closed container 1. In such a compressor, as the drive shaft 6 rotates, gas is sucked in from the suction pipe 8, compressed, and discharged from the discharge boat 14. The compressed gas fills the container 9 and is sent out through the discharge pipe 10. Sufficient oil supply holes are provided in the drive shaft 6 because the lubricating oil is supplied to the sliding parts by a pump action such as a pressure difference. Further, the motion of the orbiting scroll is stabilized by providing a hole 11 that communicates the compression chamber with a back pressure chamber 12 and introducing an appropriate pressure into the back of the orbiting scroll.

Due to this configuration, when the compressor is operated continuously, all parts are provided with sufficient functionality, but on the other hand, when the compressor is started or stopped frequently, The pressure in the back pressure chamber 12 may become greater than the pressure in the container 9 when turning the container, entering defrosting operation, or vice versa during a so-called transitional period of operation. This is a phenomenon that occurs due to the difference in the size of the space, and when this phenomenon occurs, the oil pressure supplied to each sliding part is the opposite pressure difference, and the lubricating oil 13 in the lower part of the closed container is supplied. Problems such as missing parts and stiffness of sliding parts occur.

An object of the present invention is to prevent the pressure in the back pressure chamber from becoming larger than the pressure in the closed container during the transition period of compressor operation, and to ensure the oil supply function to each contact sliding surface. .

In the high-pressure vessel type hermetic scroll compressor shown in the conventional example, the method of supplying lubricating oil to the shaft, bearings, and scroll bell plate includes: 1. a pump action that acts as the main shaft rotates; 2. Adopts a dual lubrication method based on the pressure difference of the working gas itself. However, as a result of investigation under various operating conditions, it was found that the pressure difference in the second term has a negative effect on the lubricated surface within a few minutes.

Needless to say, this creates very severe conditions for the sliding parts, and also causes functional problems as a compressor, such as stiffness and seizure.

In order to prevent the occurrence of such negative differential pressure, a so-called back pressure chamber 12, which is normally on the oil drainage side with respect to each sliding part, is provided.
A communication hole is provided in the frame that communicates with the inner space 9' of the container, which is the oil supply side, and when a normal differential pressure is applied, the communication hole is cut off, and when a negative pressure difference is applied, the communication hole is cut off. We also decided to install a valve body that opens. With this configuration, even if there is a condition where a negative differential pressure acts on the sliding surface during the transient period of operation,
The valve function quickly removes the pressure imbalance between the chambers, and as with normal startup, the pump action described in item 1 above ensures that each sliding surface has sufficient lubricating oil. supply, and as a result, the reliability of the compressor is sufficiently improved.

In addition, during the transition period, the pressure in the back pressure chamber is higher than during steady operation, and even if the pressure in the back pressure chamber is made the same as the pressure inside the closed container, the force for pressing the orbiting scroll in the axial direction is maintained. .

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. The scroll large volume R-body machine has end plates 251, 31.
A fixed scroll 2, one of which is fixed, and an orbiting scroll 3, the other of which is movable, are offset by 1806 degrees from each other and are combined so that the wraps mesh with each other. A compression mechanism section is configured. For fixed scrolling,
A suction boat 8 is provided at the outer periphery, and a discharge boat 14 is provided at the center. Furthermore, this fixed scroll 2 is fixed to a frame 4, and the orbiting scroll 3 is supported so as to be slidable by this frame 4 and the fixed scroll 2. The orbiting scroll is provided with a boss portion 16 on the side opposite to the side on which the driving crank is inserted.
This center is set at an arbitrary distance from the center of the main shaft 6, and as the main shaft 6 rotates, the orbiting scroll 3 is given an orbiting motion having this distance as a radius. In order to allow the orbiting scroll 3 to rotate while always maintaining a constant phase angle with respect to the fixed scroll 2, an anti-rotation element 7 is provided. In order to ensure stable movement of the orbiting scroll, an appropriate gas pressure is applied from the compression chamber to the back pressure chamber 12 through the throttle 11. or,
A balance weight for balancing the unbalanced amount of the orbiting scroll 3 is disposed in the back pressure chamber 12. The boss portion 16 of the orbiting scroll is a sliding bearing. The frame-side bearing relative to the main shaft 6 is also a sliding bearing. The frame 4 is provided with a communication hole 17 communicating from the back pressure chamber 12 to the outside, and a valve body 18 made of a spring material is fixed to the outlet portion by a fixing port 19. This valve body 18 has a structure that allows it to be easily operated by a pressure difference between the front and rear sides of the valve. The main shaft 6 is provided with an eccentric hole 14 for supplying oil over the entire length of the main shaft in order to function as a pump by rotation. Further, an electric element 5 is disposed at the bottom of the main shaft 6, and all these elements are housed in a closed container 1 containing lubricating oil 13 to form a closed scroll compressor. ing.

The airtight container l is provided with a suction pipe 8 and a discharge pipe 10. Further, electric power is supplied to the electric element 5 from the outside through the non-metic terminal 15. The rotation of the rotor 5b rotates the main shaft 6, and the orbiting movement of the orbiting scroll 3 leads the working gas into the compression chamber through the suction boat 8, pressurizes it, and discharges it through the discharge boat 14. Then, the airtight container is filled and finally discharged to the outside of the machine through the discharge pipe 1o.6During normal operation, the pressure in the back pressure chamber 12 is reduced by the restrictor 11 provided on the orbiting scroll, the subvep bearing, etc. Due to the action of #1, the suction pressure and the discharge pressure are approximately the average value. Due to this pressure difference, sufficient lubricating oil is supplied to the sliding parts of the bottom bearing.

4, 5, and 6 show other embodiments of the valve body provided in the frame 4. FIG.

In Figure i@4, a valve chamber 24 is provided on the side of the closed container space 9, and a presser plate 21 is attached to the frame 4 by fastening means such as bolts or joining means. The valve plate 2o is disposed so as to suitably close the communication hole 16, and is configured to close the communication hole 16 by the valve spring 22. The presser plate 21 is provided with a back pressure chamber 1 when the valve plate 2o is in the open state.
An escape hole 23 is provided for communicating between the container 2 and the container interior space 9.

FIG. 5 shows a configuration in which a valve chamber is provided on the side of the inner space 9 of the container, a presser plate is fixed to the frame, and the communication hole 16 is closed by a spherical valve component 25 using a valve spring 22. The holding plate 21 is provided with a plurality of relief holes 23 similar to those shown in FIG. 4.

FIG. 6 shows the valve chamber 24 in the back pressure chamber 129111 of the frame 4.
The holding plate 21 is fixed to the frame 4, and a relief hole 23 is provided in a part of the holding plate 21. The valve plate 24 has appropriate strength and spring force against deformation of the plate spring material, and under normal conditions,
It is configured to close the escape hole 23 of the presser plate 21.

FIG. 7 shows the valve chamber 2 in the container internal space 91IIl of the frame 4.
4, the press plate 21 is formed into a cylindrical shape, a screw thread is provided on the outside of the press plate 21, and an escape hole 23 is formed in a part of the press plate 21. By housing the valve spring 22 in the cylindrical holding plate 21 and screwing it to the frame 4, the communication hole 16 can be suitably closed by the valve plate 20.

The embodiment shown in FIGS. 3 to 7 includes a valve plate 20, a valve spring 2
2. There are only a few examples of the combinations of the holding plate 21 and the position of the valve chamber 24, and there are many combinations and variations thereof, and those with the same operation and effect are not included in the present invention. include.

According to an embodiment of the present invention, a back pressure chamber 12 is provided in a part of the frame.
A small diameter hole that conducts the airtight container and the internal space of the sealed container through the valve body.
By having nine configurations, when the pressure inside the back pressure chamber becomes higher than the pressure inside the container, the valve opens immediately to prevent a pressure difference between the chambers.

Generally, hermetic compressors used for air conditioning are started and stopped, and during heating operation, the cycle is automatically controlled to maintain high thermal efficiency. The operating condition is maintained. When entering and exiting this defrosting state, the suction pressure and discharge pressure change instantaneously at 0 or more, and during startup, shutdown, and defrosting states, the back pressure chamber and container Due to the difference in volume with the internal space, the pressure inside the back pressure chamber tends to increase for a short time, but at this time, the valve installed in the frame operates appropriately and the pressure exceeds the internal pressure of the container. It is possible to prevent this from happening. When the pressure is equalized, sufficient lubricating oil is supplied to each bearing etc. by the eccentric pumping capacity of the main shaft, and high reliability of the sliding parts of the bearing temple can be maintained. When the compressor is in normal operating condition without transients, the pressure inside the container is maintained at its highest during discharge, so the nine valve bodies installed in the frame are in a sufficiently sealed state due to the high pressure difference, and the back The pressure in the pressure chamber and the pressure inside the container will never reach equilibrium pressure,
Therefore, the amount of lubricating oil commensurate with the load is supplied to sliding parts such as bearings due to the pressure difference.For air conditioning scroll compressors, each sliding part is Since the parts are supplied with lubricating oil, high reliability is maintained.

As described above, according to the present invention, it is possible to provide a scroll-type fluid machine in which there is no stiffness between the shaft, the bearing, or other sliding contact surfaces due to insufficient supply of lubricating oil.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing a conventional hermetic scroll compressor, FIG. 2 is a plan view showing a compression mechanism, FIG. 3 is a front sectional view showing an embodiment of the present invention, and FIG. Figure, Figure 5, Figure 6
FIG. 7 and FIG. 7 are sectional views of essential parts showing various modifications of the check valve mounting portion. 1...Airtight container, 2...Fixed scroll, 3...
Orbiting scroll, 4...Frame, 5...Electric element, 6...Main shaft, 7...Rotation prevention mechanism element, buttock...
Suction port, 10...Discharge pipe, 12...Back pressure chamber, 13...Lubricating oil, 17...Communication hole, 18...Valve body. ′! A1 Port 1 Fig. 2 Fig. 3 Fig. I Fig. 4 Fig. 5 Fig. 7

Claims (1)

[Claims] The scroll compression mechanism consisting of an involute trap is fixed to the frame, and is housed in a sealed container together with an electric element and lubricating oil. The stable movement of the orbiting scroll is ensured by applying self-pressure to its back, and A scroll-type fluid machine with a refueling hole, characterized in that it has a communication hole that connects the back pressure chamber at the back of the orbiting scroll and the space inside the closed container, and a check valve that automatically opens and closes depending on the pressure difference above the communication hole. Scroll type fluid machine.