JPH0326890A - Oil feeding device for scroll compressor - Google Patents

Abstract

PURPOSE:To obtain the oil feeding mechanism which is less independent of the pressure variation and temperature variation by preparing an oil flow rate valve from a tapered piston and a spring and making the piston from the material having the larger thermal expansion rate than that of a valve cylinder. CONSTITUTION:A spring 22 which is balanced with the pressure difference between a high pressure chamber 18 and a back surface chamber 17 is installed onto the edge surface on the back surface chamber side of a piston 26, and the piston 26 is shifted according to the balance between the pressure difference and the spring force, and the oil quantity which flows into the back surface chamber 17 from the high pressure chamber 18 is controlled by varying the nozzle gap C1 between the taper of the piston 26 and a valve cylinder 25. Further, the piston 26 is made of the material having the higher thermal expansion rate than that of the valve cylinder 25, and the diameter of the piston 26 is expanded and contracted according to the temperature, and the nozzle gap C1 is varied according to the temperature. ln other words, the variation of flow rate due to the pressure difference can be adjusted by the taper of the piston 26, and the variation of the flow rate due to the temperature variation can be adjusted by the thermal expansion and contraction of the piston 26, and the flow rate of the oil can be controlled by adjusting the nozzle gap C1, and the oil feeding device in which the flow rate variation is less for the pressure variation and temperature variation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an oil supply device for a scroll compressor used as a fluid compressor for refrigeration, air conditioning, etc.

The operating principle of a conventional scroll compressor will be explained with reference to FIG. A spiral wrap 1 having substantially the same shape is attached to an end plate 2 (sixth
(See figure) When the orbiting scroll 3 and the fixed scroll 4 on the top are engaged with each other with the wrap l inside, and the orbiting scroll 3 is rotated while preventing rotation, the orbiting scroll 3 and the fixed scroll 4 are surrounded by the orbiting scroll 3 and the fixed scroll 4. Compression chamber 5 (
5a, 5b, . . .> move toward the center while gradually reducing their volume, and the fluid sealed in the compression chamber 5 increases its pressure and is discharged from the discharge port 6.

Next, the basic structure of a scroll compression machine will be explained using FIG. 6. The orbiting scroll 3 and the fixed scroll 4 are engaged with each other with the wrap 1 inside, and a rotation prevention mechanism 8 is provided between the orbiting scroll 3 and the frame 7. A crankshaft 10, which is rotatably supported by a bearing 9 at the center of the frame 7, has one end engaged with the orbiting scroll 3, and is rotationally driven by a drive source 1l. The fluid sucked in from the suction port 12 is compressed in the compression chamber 5 and flows to the discharge pipe 14 via the discharge port 6, the discharge passage 13, and the space above the frame 7. Note that these compression mechanisms are housed in a closed container 15, and a high pressure chamber 18 in which lubricating oil 16 is stored is formed above the frame 7. Further, on the back surface of the orbiting scroll 3, a back chamber 17 is formed which is surrounded by the frame 7 and the fixed scroll 4 and separated from each other in terms of pressure.

In a scroll compression machine, in order to achieve efficient compression, the sealing performance of the gap Ca between the wrap 1 and end plate 2 of each of the orbiting scroll 3 and fixed scroll 4 that form the compression chamber 5 and the gap Cb between the wraps 1 must be improved. It is important to maintain the fluid seal by supplying an appropriate amount of lubricating oil into the compression chamber 5. Further, the pressure within the compression chamber 5 acts on the orbiting scroll 3 in a direction to separate it from the fixed scroll 4,
It is necessary that the back chamber 17 has a pressure that is balanced with the pressure in the compression chamber 5. If the back chamber 17 pressure is too high, the sliding resistance between the orbiting scroll 3 and the fixed scroll 4 will increase,
On the other hand, if it is too low, a gap Cc will be created between the orbiting scroll 3 and the fixed scroll 4, resulting in leakage of fluid in the compression chamber 5, resulting in a decrease in compression efficiency.

Referring to FIG. 7, a mechanism for adjusting the oil flow rate and pressure to the rear chamber l7 shown in section A of FIG. 6 will be explained. High pressure chamber 1 in the above frame 7
8 and a valve cylinder 20 communicating with the back chamber 17, one end of which faces the high pressure side and the other end of which faces the low pressure side, and a piston 2l inserted so as to be movable in the axial direction has a tapered passage. Spring 2 having a force that balances the pressure difference between chamber 18 and back chamber 17
An oil flow regulating groove configured to be supported by 2 is disposed. On the other hand, the fixed scroll 4 is provided with a pressure adjustment mechanism 23 that maintains a constant pressure in the back chamber 1.7 in communication with the back chamber 17 and the low pressure part 5c on the outer periphery of the compression chamber 5. When the pressure in the chamber 17 rises above a predetermined pressure, the pressure adjustment mechanism 23 is activated, and the oil in the back chamber 17 is transferred to the low pressure section 5.
It has a structure that leaks into c.

Sliding and sealing performance can be improved by supplying an appropriate amount of lubricating oil to the sliding parts and sealing parts of the orbiting scroll 3 and fixed scroll 4, but if too much lubricating oil is supplied, the lubrication will flow into the compression chamber 5. Oil gets mixed in, reducing compression efficiency or causing overload due to liquid compression.

Problems to be Solved by the Invention In order to obtain a force that balances the force acting in the direction in which the orbiting scroll 3 separates from the fixed scroll 4 due to the pressure in the compression chamber 5, the pressure in the back chamber 17 is maintained at an appropriate constant pressure. ,
It is also desirable to supply an appropriate amount of lubricating oil to the sliding parts and seal parts of the orbiting scroll 3 and the fixed scroll 4, that is, into the compression chamber 5.

However, the flow rate of lubricating oil is easily affected by pressure changes and temperature changes, and in particular, changes in temperature cause significant changes in the viscosity of the oil, which has a large effect on the flow rate.

The present invention provides an oil supply mechanism for a scroll compressor that is less dependent on temperature changes as well as pressure changes.

Means for Solving the Problems In order to solve the above problems, the first invention provides a tapered piston that is movable in the axial direction of the valve cylinder between the high pressure chamber and the back chamber. In addition to the oil flow valve, which is constructed by engaging a spring that expands and contracts depending on the pressure difference in the chamber, the piston is made of a material with a higher coefficient of thermal expansion than the valve cylinder, and the cross-sectional area of the nozzle restriction due to the thermal expansion of the piston is changed to adjust the oil flow rate. This configuration has a structure that reduces the temperature dependence of .

In addition to the above configuration, the second invention provides a throttle valve made of a material having a higher coefficient of thermal expansion than the valve cylinder and the piston in the valve cylinder at one end of the piston, so that the throttle valve can accommodate pressure changes and temperature changes. It has a stepped aperture configuration.

In addition to the above configuration, the third invention provides a heat-sensitive deformable body (for example, bimetallic material) with a throttle gap in the opening on either the high-pressure side or the low-pressure side of the piston, so that the opening changes according to temperature changes. The structure is such that the flow path area is changed to reduce the temperature dependence of the oil flow rate.

Function The function of the first invention is to change the noise gap between the piston and the valve cylinder by the taper of the piston, control the amount of lubricating oil flowing from the high pressure chamber to the back chamber, and to make the piston made of a material with a large coefficient of thermal expansion. By changing the nozzle gap according to the temperature change of the lubricating oil, the change in flow rate due to pressure difference is caused by a change in the flow path area due to the taper of the piston, and the change in flow rate due to temperature change is caused by thermal expansion and contraction of the piston. The flow rate of lubricating oil can be controlled by adjusting.

The action of the second invention is to change the nozzle gap between the valve cylinder and the valve cylinder by the taper of the piston, and to control the amount of lubricating oil flowing from the high pressure chamber to the back chamber. The throttle valve, which is made of

The function of the third invention is that the nozzle gap of the valve cylinder changes due to the taper of the piston, and the amount of lubricating oil flowing from the high pressure chamber to the back chamber is controlled. The amount of curvature changes depending on temperature changes, and the aperture gap changes. Therefore, the flow rate change due to the pressure difference is caused by a change in the flow path area due to the taper of the piston, and the flow rate change due to temperature change can be controlled by changing the throttle gap by the amount of curvature of the heat-sensitive deformable body.

EXAMPLE Hereinafter, an oil supply system for a scroll compressor machine according to a first example of the present invention will be described with reference to FIG.

FIG. 1 shows the configuration of the oil supply device. The frame 7 described in the above-mentioned basic configuration of the oil supply system for a scroll compressor machine has a valve cylinder 2 connected to the high pressure chamber 18 and the back chamber 7.
5, and a tapered piston 26 is inserted so as to be movable in the axial direction.A spring 22 is provided on the end surface of the piston 26 on the rear chamber side to balance the pressure difference between the high pressure chamber 18 and the rear chamber l7. The piston 26 moves in accordance with the balance between the pressure difference and the spring force, and the nozzle gap C1 between the taper of the piston 26 and the valve cylinder 25 changes to control the amount of oil flowing from the high pressure chamber 18 to the back chamber 17.

Furthermore, the piston 26 is made of a material with a higher coefficient of thermal expansion than the valve cylinder 25, so that the diameter of the piston 25 expands and contracts depending on the temperature.
The nozzle gap C1 also changes depending on the temperature.

In other words, the flow rate change due to pressure difference is caused by the taper of the piston 26, and the flow rate change due to temperature change is caused by the thermal expansion and contraction of the piston 26.The nozzle gap CI can be adjusted and the oil flow rate can be controlled. It is possible to obtain a lubricating device with little change in flow rate in response to both changes.

FIG. 2 shows an oil supply system for a scroll compressor machine according to a second embodiment of the present invention. A valve cylinder 30 is inserted into the frame 7 described in the above-mentioned basic configuration of the scroll compression device, communicating with the high pressure chamber 18 and the back chamber 17, and a tapered piston 31 is inserted so as to be movable in the axial direction. A spring 22 that balances the pressure difference between the high pressure chamber 18 and the back chamber 17 is provided on the rear chamber side end surface of the piston 31, and the piston 31 moves according to the balance between the pressure difference and the spring force, and the taper of the piston 3l and The nozzle clearance C3 with the valve cylinder 30 changes, and the high pressure chamber 1
8 to the back chamber l7.

Furthermore, the valve cylinder 30 and the piston 3 installed in the valve cylinder 30
The throttle valve 32, which is made of a material with a coefficient of thermal expansion greater than 1, expands and contracts due to changes in the temperature of the substitute oil 16, and the throttle gap C4 changes. Further, the throttle gap C4 communicates with the nozzle gap C through a flow path 33.

That is, the flow rate change due to a change in the pressure difference between the high pressure chamber 18 and the back chamber 17 is caused by the taper of the piston 31, and the flow rate change due to a temperature-dependent viscosity change of the lubricating oil l6 is caused by the throttle valve 32.
The flow rate of the lubricating oil can be controlled by adjusting the throttle gap C4 through thermal expansion and contraction of the lubricating oil, resulting in an oil supply system that exhibits little change in flow rate in response to both changes in pressure and temperature.

FIG. 3 shows an oil supply device for a scroll compressor machine in a third embodiment of the present invention. A high pressure chamber l8 is installed in the frame 7 described in the basic configuration of the scroll compressor described above.
A valve cylinder 40 is inserted and communicated with the rear chamber 17, and a tapered piston 41 is inserted so as to be movable in the axial direction.The end surface of the piston 41 on the rear chamber side is connected to the high pressure chamber 18 and the rear chamber l7. A spring 22 is provided to balance the pressure difference, and the piston 41 moves according to the balance between the pressure difference and the spring force, and the piston 4l
The nozzle interval C between the taper and the valve cylinder 40 changes, and the amount of oil flowing from the high pressure chamber 18 to the back chamber 17 is controlled.

Furthermore, a heat-sensitive deformable body (for example, a bimetal) 43 is disposed in the opening 42 at the end of the piston 41 with a throttle gap C6.
The amount of curvature changes depending on the temperature change of the oil, and the throttle gap C6 changes.

That is, the flow rate change due to a change in pressure difference between the high pressure chamber l8 and the back chamber 17 is due to the displacement of the taper due to the movement of the piston 41, and the flow rate change due to temperature change is due to the displacement of the amount of curvature of the heat-sensitive deformable body 43, and the flow rate change is due to the change in the amount of curvature of the heat-sensitive deformable body 43. By adjusting C6, it is possible to obtain an oil supply system that has little change in flow rate even with changes in both pressure and temperature.

FIG. 4 is a graph showing the temperature/flow rate characteristics of the oil supply system in each of the above embodiments. can respond to both pressure changes and flow rate changes, and the flow rate is approximately saturated above a certain temperature.

Effects of the Invention As described above, according to the present invention, the temperature dependence of the oil flow rate can be reduced.

As a result, the pressure in the back chamber can be maintained at an appropriate constant pressure, and an appropriate amount of lubricating oil can be supplied into the sliding and sealing parts of the orbiting scroll and the fixed scroll, that is, into the compression chamber. Effects such as prevention of overload due to compression can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the oil supply device for a scroll compressor machine according to the first embodiment of the present invention, FIG. 2 is a cross-sectional view of the oil supply device for a scroll compressor machine according to the second embodiment of the present invention, and FIG. Third actual slope of the present invention - - i Fig. 5 is a plan view of the compression section showing the basic principle of a scroll compression machine, Fig. 6 is a longitudinal sectional view showing the overall structure of the scroll compression machine, and Fig. 7 6 is a detailed sectional view of the conventional oil flow valve mechanism of the scroll compressor shown in FIG. 6. FIG. 17...Back chamber, l8...High pressure chamber, 2
5.30.40... Valve cylinder, 26.31.41.
...Piston, 22...Spring, 32...
...throttle valve, 42...opening, 43...
...Heat-sensitive deformable body.

Claims (3)

[Claims] (1) Two scroll bodies with wraps standing upright on the end plate are engaged with each other with the wraps inside, and one scroll rotates in conjunction with the other scroll body while being prevented from rotating, compressing the fluid. In a scroll compression machine that performs An oil supply device having a constant pressure valve therebetween, the oil flow valve being connected to a tapered piston movable in the axial direction of the valve cylinder, with one end facing a high pressure chamber and the other end facing a back chamber. and a spring that engages with the rear chamber-side end surface of the piston and expands and contracts in response to a pressure difference acting on each end surface, and the piston is made of a material having a higher coefficient of thermal expansion than the valve barrel. Oil supply system for scroll compressor machines. (2) A throttle valve made of a material with a higher coefficient of thermal expansion than the valve barrel and the piston is provided in the valve barrel on the high pressure side of the piston, and a nozzle throttle portion formed by the valve barrel and the piston is formed from the gap between the throttle valve. 2. The oil supply device for a scroll compressor machine according to claim 1, further comprising a flow path formed in the scroll compressor. (3) The oil supply device for a scroll compressor machine according to claim 1, wherein a heat-sensitive deformable body is provided with a throttle gap in the opening of either the high pressure side or the low pressure side of the oil flow valve.