JPH0727064A - Scroll type compressor - Google Patents

Abstract

PURPOSE:To prevent overcompression by introducing gas of a high pressure part into a low pressure part by sliding a slider of a power variable mechanism so as to variably generate power suited for a low load operation, in the case of decreasing a condensation temperature and pressure by a low load at the time of operation in the winter season. CONSTITUTION:When a turning scroll 11 is turned relating to a fixed scroll 12, according to decreasing the volume of compression space partitioned between these scrolls, gas is compressed and delivered from a delivery port 13. Now when decreased a condensation temperature and pressure by a low load at the time of operation in the winter season or the like, a delivery pressure introduced from the delivery port 13 to a delivery pressure introducing hole 17 is increased larger than a total of case internal pressure introduced from an in-case introducing hole 22 and elastic force of a retaining spring 20. As a result, since a slider 19 of a power variable mechanism A is slid to open the delivery pressure introducing hole 17, both high and low pressure guide holes 23, 24 communicate through a communication hole 21 of the slider 19. Accordingly, gas of a high pressure part in the compression space is introduced into a low pressure part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll type compressor used as a compressor constituting a refrigerating cycle of an air conditioner, for example.

[0002]

2. Description of the Related Art For example, a compressor constituting a refrigeration cycle of an air conditioner has extremely low motion noise as compared with an ordinary rotary compressor, and a suction valve and a discharge valve are not required and the number of parts is small. There is a tendency for scroll-type compressors that are small in number and have good compression performance to be used frequently.

This type of scroll compressor accommodates an electric compressor main body in which a motor unit is connected to one end side of a rotating shaft and a compressor unit is connected to the other end side in a hermetically sealed case, and the hermetically sealed case of the hermetically sealed case is described. An oil sump portion for collecting lubricating oil is formed on the inner bottom portion.

The compression mechanism section comprises a fixed scroll and an orbiting scroll, and the spiral blades of each scroll are meshed with each other, and the blades and the end plate of each scroll form a compression space.

With the rotation of the rotating shaft, the orbiting scroll orbits, sucks a low-pressure gas refrigerant, which is the gas to be compressed, into the compression space, and compresses and discharges it by reducing the volume of the compression space. .

[0006]

By the way, a characteristic of such a scroll compressor is that the compression ratio is fixed due to its structure. In a climatically stable region where the annual temperature fluctuation is relatively small, it is easy to set standard conditions and it is not difficult to obtain the design compression ratio, but there are four seasons like Japan, and the annual temperature range is wide. If it is large, it will lead to disadvantages.

That is, the fluctuation of the outside air temperature causes the fluctuation of the condensing pressure and the condensing temperature, and has a great influence on the setting of the compression capacity of the compressor and the heat exchange capacity of the heat exchanger.
For example, a compressor designed with a standard compression ratio has a low condensing temperature and condensing pressure when the load is low in winter (low temperature), so that the compressor falls into an over-compressed state and the loss is remarkable.

As shown in the Mollier diagram of FIG. 3, under standard conditions, a to b is a compression step, b to c is a condensation step, c to d is a decompression step, and d to a is an evaporation step. At low temperature, once compressed from a to b, b to f
There is a pressure drop at the enthalpy and a difference in enthalpy occurs. With such a pressure drop, the condensation process from f to g under a low load is performed.

The work of the compressor at the compression ratio set under the standard conditions is i ₁ which is the enthalpy amount from a to b, but when the load is low, the enthalpy amount from b to f is the same. A certain Δi ₁ will be recorded as a loss.

The present invention has been made by paying attention to the above circumstances, and its purpose is to eliminate the disadvantage that the compression ratio is constant by making the best use of the characteristics of low vibration and low noise. The present invention intends to provide a scroll compressor capable of improving the compression performance by changing the capacity adapted to the initial designed compression ratio.

[0011]

In order to satisfy the above object, a scroll compressor of the present invention accommodates a compression mechanism portion consisting of a fixed scroll and an orbiting scroll in a hermetically sealed case, and each scroll has a spiral shape. The wing portions are meshed with each other, a compressed space is formed by these wing portions and the end plate portion of each scroll, the compressed gas is sucked, and the volume of the compressed space is reduced,
In a scroll compressor that compresses and discharges, a discharge port for guiding the compressed gas compressed to a predetermined pressure from the compression space into the sealed case is provided, and a discharge pressure introduction hole communicating with this discharge port is provided. One end of the switching hole is communicated with the discharge pressure introducing hole, the other end is closed, and a slider having a communication passage is movably accommodated in the switching hole, and the switching hole and the sealed case are connected to each other. The slider is moved and urged by the difference between the case internal pressure, which communicates with the case internal pressure introducing hole, and is guided therethrough via the case internal pressure introducing hole, and the discharge pressure introduced through the discharge pressure introducing hole. Department,
Each of the low pressure portions and the switching hole are communicated with each other by the high pressure guide hole and the low pressure guide hole.

[0012]

According to this structure, the high pressure guide hole and the low pressure guide hole are communicated with each other via the communication passage of the slider, depending on the position of the slider. Or it is blocked by a slider. Therefore, the capacity can be varied, and the pressure loss at a low load is suppressed to a minimum according to the setting of the standard condition.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below by applying a horizontal scroll type compressor as shown in FIG. 1 which is used in a refrigeration cycle circuit of an air conditioner, for example. In the figure, 1 is a closed case, and in this closed case,
In the figure, a support frame 2 is provided on the left side. The support frame 2 rotatably supports one end of a rotary shaft 3 extending in the horizontal direction.

The other end of the rotary shaft 3 is pivotally supported by a sub bearing 2A provided in the sealed case 1. A compression mechanism section 4 described later is connected to the support frame 2 side, and at other positions, an electric motor section 7 including a stator 5 and a rotor 6.
Is provided.

The compression mechanism section 4 includes the support frame 2
The orbiting scroll 11 is rotatably supported via the Oldham ring 10, and the fixed scroll 12 meshes with the orbiting scroll.

The Oldham ring 10 restricts the rotation of the orbiting scroll 11 so that only the orbiting motion is performed. The orbiting scroll 11 has an end plate portion 11a having a boss portion 11c that engages with the eccentric portion 3a of the rotary shaft 3, and a spiral wing portion 11b integrally provided on the upper surface side of the end plate portion 11a.
Consists of.

The fixed scroll 12 has an end plate portion 12a.
And a spiral wing 12 that is integrally projectingly provided on the lower surface of the end plate 12a and meshes with the wing 11b of the orbiting scroll 11.
b.

A pair of compression spaces S, S are formed by the end plate portions 11a, 12a and the blade portions 11b, 12b of the orbiting and fixed scrolls 11, 12, and a refrigerant gas as a compressed gas is supplied from the peripheral end side. It can be taken in, moved to the center side, and at the same time, its volume can be reduced to perform a compression action.

A discharge port 13 is provided through the central portion of the fixed scroll end plate portion 12a so as to communicate with the spiral center of the compression space S. A suction pipe 14 is provided so as to penetrate the closed case 1. This suction pipe 14
Also penetrates the fixed scroll end plate portion 12a, and its opening end faces the peripheral end portion of the compression space S. The suction pipe 14 extending to the outside communicates with an evaporator of a refrigeration cycle (not shown).

A discharge pipe 15 is connected to a portion of the closed case 1 on the side of the electric motor unit 7 and extends to the outside to communicate with a condenser of a refrigeration cycle (not shown). As shown enlarged in FIGS. 2A and 2B, a variable capacity mechanism A is provided.

That is, the end plate portion 12a of the fixed scroll 12 is provided with a pair of switching holes 16 and 16 along the plate thickness direction so that the discharge port 13 as the end plate axis is symmetrical.

These switching holes 16 are provided in the end plate portion 12a.
One end of each of them is communicated with the discharge port 13 via a discharge pressure introducing hole 17 which is a hole smaller than this. The other end of the switching hole 16 is opened on the peripheral surface of the end plate portion 12a, and a closing plug 18 is provided here to completely seal the opening end.

Further, a slider 19 and a pressing spring 20 which is an elastic body are housed in the switching hole 16. The diameter of the slider 19 is very slightly smaller than the diameter of the switching hole 16 and the slider is freely movable along the axial direction of the switching hole, but there is almost no gas leakage between them. It has been incorporated.

A communication groove 21, which is a communication passage having a predetermined length, is provided on the peripheral surface of the slider 19 along the moving direction. Since the pressing spring 20 is provided between the fixed closing plug 18 and the movable slider 19,
The slider is elastically pressed and biased in the direction of closing the discharge pressure introducing hole 17.

The fixed scroll end plate portion 12a is provided with a case pressure introducing hole 22 for communicating the switching hole 16 portion for accommodating the pressing spring 20 and the inside of the closed case 1. It is adapted to be guided to the switching hole 16.

On the other hand, the fixed scroll end plate portion 12a is provided with a high pressure guide hole 23 which connects the high pressure portion located near the center of the compression space S and the switching hole 16 to each other. Further, a low pressure guide hole 24 is provided which connects the low pressure portion near the peripheral end of the compression space S and the switching hole 16.

The end surface of the slider 19 is the case pressure introducing hole 17
, The high-pressure guide hole 23 faces and communicates with the communication groove 21 provided in the slider.
The low pressure guide hole 24 is set so as to be closed by the peripheral surface of the slider.

For a reason to be described later, when the slider 19 presses the pressing spring 20 to contract the most and the end surface of the slider is separated from the case pressure introducing hole 17, the high pressure guide hole 23 and the low pressure guide hole 24 are provided. Both are set so as to communicate with the communication groove 21.

Then, the electric motor 7 is energized to turn the rotary shaft 3
When is rotated, the orbiting scroll 11 orbits. The low-pressure gas refrigerant that is the gas to be compressed is sucked directly from the suction pipe 15 to the circumferential end side of each compression space S.

With the orbiting movement of the orbiting scroll 11, the compression space S moves to the axial center side and the volume decreases, and the gas introduced therein is compressed. When the high pressure rises to a predetermined pressure, the discharge port 13 is closed to the closed case 1.
Is discharged inside.

The high-pressure gas fills the sealed case 1, and is further discharged from the discharge pipe 15 to a condenser which is an external refrigeration cycle constituent device. In particular, in a scroll compressor in which the compression ratio is set under standard conditions of summer operation, the condensing pressure is high during the operation at the same time. (The condensing pressure is equal to the case internal pressure, which is the internal pressure of the closed case 1.) Therefore, the discharge port 1 is compressed in the compression space S.
The gas pressure discharged from 3 tends to be lower than the case internal pressure, which is the condensation pressure. That is, case pressure>
The discharge pressure is reached.

At this time, as shown in FIG. 2A, the sum of the gas pressure in the case guided to the switching hole 16 through the case pressure introducing hole 22 and the elastic biasing force of the pressing spring 20 is
The discharge pressure becomes higher than the discharge pressure introduced from the discharge port 13 to the discharge pressure introducing hole 17, and the slider 19 moves to the discharge pressure introducing hole 17
The slide is urged to close.

The high pressure guide hole 23 communicating with the high pressure portion of the compression space S faces the communication groove 21 provided in the slider 19, while the low pressure guide hole 24 communicating with the low pressure portion is closed by the peripheral surface of the slider. .

Therefore, in the compression space S, the compression pressure gradually increases from the low pressure portion to the high pressure portion, and when the maximum pressure is reached, the normal compression action is performed in which the pressure is discharged from the discharge port 13.

In winter operation of the compressor,
The load becomes low and the condensing temperature and pressure decrease. Therefore, if there is no state change in the conventional compression mechanism, overcompression will occur as described above.

However, the compression mechanism portion 2 of the present invention operates as described below. That is, as shown in FIG. 2B, the discharge pressure introduced from the discharge port 13 to the discharge pressure introducing hole 17 is equal to the gas pressure in the case introduced through the case pressure introducing hole 22 and the elasticity of the pressing spring 20. It will be larger than the total with the power.

The slider 19 receives the gas pressure in the case and is biased by the slide to open the discharge pressure introducing hole 17. At this time, the high pressure guide hole 23 communicating with the high pressure portion of the compression space S faces the communication groove 21 provided in the slider 19, and the low pressure guide hole 24 communicating with the low pressure portion also faces the communication groove.

Therefore, the high pressure guide hole 23 and the low pressure guide hole 24 are communicated with each other through the communication groove 21, and the low pressure portion and the high pressure portion of the compression space S are directly communicated with each other. High-pressure release is achieved when the gas in the high-pressure portion is guided to the low-pressure portion and discharged from the discharge port 13.

The gas filled in the closed case 1 is discharged from the discharge pipe 15 at a pressure lower than that in the normal operation,
The capacity is adjusted to suit low load operation. This state continues, and when the discharge pressure becomes equal to the case internal pressure, the slider 19 stops moving. When the normal operation is resumed and the condensing pressure rises, the operation described above is performed.

As described above, the conditions for starting and ending the operation of the variable capacity mechanism A, which is a high pressure release at low load, can be freely determined by setting the initial design compression ratio (standard condition). .

The scroll compressor has been described as constituting a refrigeration cycle of an air conditioner.
The present invention is not limited to this, and can be used as a compressor for compressing another gas to be compressed. Further, the invention is not limited to the horizontal scroll compressor, and may be the same vertical model.

[0042]

As described above, according to the present invention, the discharge pressure introducing hole communicating with the discharge port, the switching hole having one end communicating with the discharge pressure introducing hole and the other end closed, and the switching hole. A slider housed in the operation hole, a case internal pressure introducing hole that communicates the switching hole with the closed case, a high-pressure guide hole that communicates the high pressure portion and the low pressure portion of the compression space with the switching hole, and Since a means for varying the capacity consisting of a low-pressure guide hole is provided, the characteristics of low vibration and low noise can be used as they are to eliminate the disadvantage of a constant compression ratio, and the capacity can be varied according to the initial designed compression ratio. However, there is an effect that the compression performance can be improved.

[Brief description of drawings]

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

FIG. 2A is a vertical cross-sectional view of the variable capacity mechanism in a normal operation state according to the embodiment. FIG. 6B is a vertical cross-sectional view of the variable capacity mechanism in the high pressure release state.

FIG. 3 is a Mollier diagram under standard conditions and low load.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sealed case, 12 ... Fixed scroll, 11 ... Orbiting scroll, 4 ... Compression mechanism part, S ... Compression space, 13 ... Discharge port, 16 ... Switching hole, 17 ... Discharge pressure introduction hole, 19
... slider, 21 ... communication groove, 20 ... elastic body, 17 ... case pressure introducing hole, 23 ... high pressure guide hole, 24 ... low pressure guide hole.

Claims (1)

[Claims] Claim: What is claimed is: 1. A hermetically-sealed case accommodates a compression mechanism section composed of a fixed scroll and an orbiting scroll, the spiral blades of each scroll are meshed with each other, and the scroll blade and the end plate of each scroll are compressed. In a scroll compressor that forms a space, sucks in the compressed gas, and compresses and discharges it by reducing the volume of the compression space, the compressed gas that has been communicated with the compression space and has been compressed to a predetermined pressure is introduced into a closed case. A discharge port that guides the discharge, a discharge pressure introducing hole that communicates with the discharge port, a switching hole that has one end communicating with the discharge pressure introducing hole, and the other end is blocked, A slider, which is movably accommodated and has a communication passage provided along the moving direction, communicates the switching hole with the inside of the closed case, and the case internal pressure guided to the switching hole through The case internal pressure introducing hole for moving and urging the slider by the difference between the discharge pressure introduced through the discharge pressure introducing hole, the high pressure portion of the compression space, the low pressure portion, and the switching hole are communicated with each other. A scroll compressor comprising a high-pressure guide hole and a low-pressure guide hole which are communicated with or cut off from each other via a communication path of the slider according to the position of the slider.