JP2536227B2 - High-pressure dome type scroll compressor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high pressure dome type scroll compressor, and more particularly to a small and small capacity scroll compressor.

(Prior Art) Conventionally, a high-pressure dome type scroll compressor is disclosed in, for example, Japanese Patent Laid-Open No. 61-152983 and, as shown in FIG. 3, a first scroll (F) and a second scroll (S). ) And are arranged to face each other vertically via the frame (G), and a boss cylinder (B) is projectingly provided on the rear side of the center of the end plate (W) of the second scroll (S), and the drive shaft ( The pin portion (P) provided at the shaft end portion of (K) is inserted and the second scroll (S) is orbitally driven relative to the first scroll (F) as the drive shaft (K) rotates. I am trying.

Further, a seal ring (R) is provided on the rear surface side of the end plate (W) of the second scroll (S) and outside the boss cylinder (B) to radially seal the central portion of the rear surface and the outer peripheral portion of the rear surface of the end plate (W). ), The central portion of the back surface of the second scroll (S) is exposed to the high-pressure chamber (H), and the outer peripheral portion of the back surface is exposed to the low-pressure chamber (L). End plate (W)
The upper surface of the second scroll (F) is pressed against the thrust receiving surface (E) of the first scroll (F) to support the thrust bearing of the second scroll (S).

That is, by driving the second scroll (S) to revolve relative to the first scroll (F) by the drive rotation of the drive shaft (K), the compressed fluid sucked from the suction port is transferred to each scroll ( F) is compressed in the compression chamber formed between the spiral bodies (M) and (N) of (S), and is discharged from the discharge port (O).
For the separating force that tries to separate the scroll (S),
The high pressure acts on the central portion of the rear surface of the second scroll (S) to constantly increase the pressing force on the thrust receiving surface (E), and due to the difference from the separating force, the second force is applied by the pressing force. Scroll (S) to the thrust receiving surface (E)
It is always pressed against.

Therefore, even when the high pressure of the compressed fluid is low and the differential pressure of the low pressure is low, the repulsive force overcomes and the second scroll (S) is pressed against the thrust receiving surface (E). In addition, the diameter of the high pressure acting surface acting on the second scroll (S), that is, the seal ring (R) is set.

(Problems to be solved by the invention) However, as described above, the thrust receiving surface (E) of the second scroll (S) is applied to the thrust receiving surface (E) of the second scroll (S) by the pressing force of the high pressure acting on the high pressure acting surface. In the structure of pressing against and sealing, the sealing performance is not deteriorated even at the low differential pressure, that is, the scroll body (N) in the second scroll (S) and the end plate in the first scroll (F). Since it is necessary to set the pressing force so that leakage does not occur between (U) and (U), the pressing force is increased at a high differential pressure where the high pressure of the compressed fluid is high and the differential pressure with the low pressure is high. It is too strong, and each scroll (F) (S)
However, there is a problem that the relative orbital driving load becomes large, the operating efficiency of the compressor decreases, and the reliability of the thrust receiving surface (E) also decreases.

The object of the present invention is to operate regardless of the operating conditions, in other words, the operation can be performed without the thrust load exceeding a predetermined load in the entire operating range, the operation efficiency of the compressor can be improved, and the reliability of the thrust receiving surface can be improved. There is a point to be able to improve.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a compression element (5) including a first scroll (3) and a second scroll (4) in a closed casing (1). A high pressure dome type scroll compressor in which a motor (7) is installed and a discharge pipe (10) is opened in the casing (1), and a high pressure side pressure receiving surface (12) is provided on the back surface of the second scroll (4). And the low pressure side pressure receiving surface (15) are defined, and the pressing force due to the high pressure side pressure acting on the high pressure side pressure receiving surface (12) overcomes the separating force due to the internal pressure of the compression element (5), The second
First thrust receiving surface (16) for supporting the scroll (4)
And a second thrust receiving surface (17) for supporting the second scroll (4) when the separating force overcomes the pressing force, and the second scroll (4) is provided with the first thrust receiving surface. The high pressure side pressure receiving surface (12) has a high differential pressure between the high pressure and the low pressure within the operating range, while being interposed between the (16) and the second thrust receiving surface (17) via a predetermined gap. During the high differential pressure operation, the pressure receiving area is a pressing force with reference to the surface pressure acting on the first thrust receiving surface (16).

In the present invention, the high differential pressure operation is an operation under normal pressure operating conditions in the operating range, and the low differential pressure operation is mainly a defrost operation. The criticality with the differential pressure is clear.

An intermediate pressure may be applied to the low pressure side pressure receiving surface (15), but it is preferable to apply a low pressure.

(Operation) The high-pressure side pressure receiving surface (12) is based on the surface pressure that acts on the first thrust receiving surface (16) during high differential pressure operation where the differential pressure between the high pressure and low pressure increases within the operating range. The second scroll (4) has a first thrust receiving surface (16) and a second thrust receiving surface (1
Since it is interposed between the high pressure side of the second scroll (4) and the high pressure pressure of the compressed fluid, the high pressure side pressure receiving surface of the second scroll (4) is operated at a high differential pressure condition where the pressure difference from the low pressure is high. The pressing force due to the high-pressure side pressure acting on (12) becomes the separating force due to the internal pressure of the compression element (5), that is, the force for separating the second scroll (4) from the first scroll (3). After defeating, the second scroll (4) moves to the first
Thrust is supported only by the thrust receiving surface (16).

Further, when the high pressure of the compressed fluid becomes low and the differential pressure with the low pressure is low and the operation is performed under a low differential pressure condition, the separating force overcomes the pressing force, so the second scroll (4)
Is thrust supported only by the second thrust receiving surface (17).

That is, the above-mentioned pair of thrust receiving surfaces (16, 17) are provided, and the second scroll (4) is provided with these thrust receiving surfaces (1
6) A high pressure side pressure receiving surface (12) defined on the back surface of the second scroll (4) is provided between the high pressure pressure and the low pressure pressure within an operating range while being disposed with a predetermined gap between them. At the time of high differential pressure where the differential pressure becomes high, the first thrust receiving surface (16)
As a pressure receiving area which is a pressing force based on the surface pressure acting on the high pressure side pressure receiving surface (12), and the low pressure side pressure receiving surface (15) is lower than the high pressure side pressure. The pressure on the low pressure side is made to act, and when the differential pressure is high, the first pressure is applied.
The thrust receiving surface (16) is thrust-supported, and the second thrust receiving surface (17) is thrust-supported when the differential pressure is low. Just by the difference between the pressing force and the separating force, a large pressing force acts at the time of high differential pressure operation like when the pressing force is set to the pressure receiving area that overcomes the separating force at the time of low differential pressure in the past. There is no such thing.

That is, since it is not necessary to set the pressing force to the pressing force required at the low differential pressure, the pressing force is too strong at the high differential pressure, the thrust load increases, and the operation efficiency of the compressor decreases, Since the reliability of the thrust receiving surface (16) does not decrease, either thrust receiving surface (16) (17) with the proper pressing force for the second scroll (4) according to the operating conditions.
Can be supported by.

Furthermore, the separating force due to the internal pressure of the compression element (5) is
When the pressing force by the high pressure side pressure acting on the high pressure side pressure receiving surface (12) of the scroll (4) is overcome, and when operating under a low differential pressure condition, the first scroll (3) and the second scroll (4) ) With a predetermined gap, the seal of this gap can be sufficiently oil-sealed with the oil injected into the compression element, and a large amount of liquid refrigerant is sucked into the compression element to prevent overcompression. Even if there is a possibility that it will occur, the second scroll (4) is separated from the first scroll (3) by the predetermined gap, and the scrolls (3) and (4) are compressed through the predetermined gap. Since the liquid refrigerant can be forcibly discharged along with the action, liquid compression can also be avoided.

Further, when a low pressure is applied to the low pressure side pressure receiving surface (15), as compared with a case where an intermediate pressure is applied, the temperature rise of the compressed fluid sucked into the compression element (5) is eliminated, and the compression efficiency is improved. Can be eliminated.

(Example) The high-pressure dome type scroll compressor shown in Fig. 1 is applied to a refrigeration system. The first scroll (fixed to the frame (2) is fixed to the upper inside of the closed casing (1). 3) and the spiral wrap (3) of the first scroll (3)
a compression element (5) consisting of a second scroll (4) with a spiral wrap (4a) that fits with a) is installed, and a drive shaft (6) is provided below this compression element (5). It has a built-in motor (7).

An eccentric pin portion (6a) is provided at the upper end of the drive shaft (6), and the pin portion (6a) is projected to the center of the rear surface of the end plate (4b) of the second scroll (4). The second scroll (4) is revolvingly driven with respect to the first scroll (3) by the rotation of the drive shaft (6) by being inserted into the boss cylinder (4c) to be installed, and the scroll (3) (4) In the compression chamber defined between the inner surfaces of the wraps (3a) (4a) and the end plates (3b) (4b), the low pressure gas refrigerant sucked from the suction pipe (8) is compressed and compressed. Is discharged from the discharge hole (9) into the casing (1) and is discharged to the outside from an external discharge pipe (10) provided in the casing (1).

Further, the end plate (4b) of the second scroll (4)
On the back surface of the boss, between the radial outer position of the boss cylinder (4c) and the frame (2), a seal mainly made of metal that radially divides the back surface center area and the outer peripheral area of the end plate (4b). The central region is opened to the casing (1) through a ring (11), and the central region, that is,
A high-pressure side pressure receiving surface (12) is formed inside the seal ring (11), and the outer peripheral region is partitioned from the casing (1) by the frame (2) to form the frame (2). A low pressure chamber (14) communicating with the suction pipe (8) is provided through a communication hole (13) provided in the, and a low pressure side pressure receiving surface (15) is formed in the outer peripheral region.

In addition, in FIG. 1 and 2, (20) is the seal ring (1
This elastic body (20) is an elastic body mainly composed of an O-ring which is fitted in the bottom of a fitting groove (21) for fitting 1) and presses the seal ring (11) to the second scroll (4) side.
The sealing effect is enhanced by pressing with.
Further, as described above, instead of using the elastic body (20),
The seal ring (11) itself may be formed of an elastic material such as Teflon resin.

In addition, a pressing force (push-up) by the high pressure side pressure acting on the high pressure side pressure receiving surface (12) is applied to the outer periphery of the first scroll (3) facing the outer peripheral portion of the end plate (4b) of the second scroll (4). The force supporting the second scroll (4) when the force overcomes the separating force (pressing force) of the second scroll (4) with respect to the first scroll (3) by the internal pressure of the compression element (5). The first thrust receiving surface (16) is provided, and the first thrust receiving surface (16) is provided radially outward of the seal ring (11) so that the second
When the separating force (pressing force) overcomes the pressing force (pushing force) against the frame (2) facing the center of the outer peripheral area of the end plate (4b) of the scroll (4), the second scroll ( The second thrust receiving surface (17) for supporting 4) is provided. The first thrust receiving surface (16) is used for the second thrust
When supporting the scroll (4), a slight gap (20 to 60 μ, preferably 40 μ) is formed between the second thrust receiving surface (17) and the back surface of the second scroll (4). is there.

Thus, in the above configuration, the pressure receiving area of the high pressure side pressure receiving surface (12) defined by the seal ring (11) is the operating condition where the high and low differential pressure becomes a low differential pressure, such as during defrost operation. However, the thrust force acting on the first thrust receiving surface (16) is set to be optimal under normal operating conditions within the operating range. Even if
The thrust force will not become excessive.

Therefore, in normal operating conditions within the operating range, that is, during high differential pressure operation, the pressing force due to the high pressure side pressure acting on the high pressure side pressure receiving surface (12) overcomes the separating force,
The second scroll (4) has the first thrust receiving surface (1
Since it is supported by 6), the pressing force does not increase at the time of high and low differential pressure, and the load of the revolution drive of the second scroll (4) does not increase.

Moreover, in the low differential pressure operation such as the defrost operation, the separation force of the second scroll (4) from the first scroll (3) by the internal pressure of the compression element (5) overcomes the pressing force. , The second scroll (4)
It is supported by the second thrust receiving surface (17) apart from the first thrust receiving surface (16), and even at a low differential pressure, the first and second scrolls ( The sealability between 3) and 4) does not deteriorate.

That is, a gap between the first thrust receiving surface (16) and the second thrust receiving surface (17), that is, one thrust receiving surface (16).
Or when supporting the second scroll (4) in 17),
The gap formed between the other thrust receiving surface (17 or 16) and the second scroll (4) is preferably about 20 to 60 μ.
When the second scroll (4) is supported by the second thrust receiving surface (17), the end plate (3b) of the first scroll (3) and the wrap of the second scroll (4) are 40 μm. Although it will be separated from the end face of (3b) in correspondence with the gap, it can be sufficiently oil-sealed by the lubricating oil injected into the compression element (5), and a tip seal (18) is provided. As a result, sufficient sealing performance can be secured.
Further, even when a large amount of liquid refrigerant may be sucked into the compression element to cause overcompression, the separating force due to the internal pressure of the compression element (5) causes the high pressure side pressure receiving surface of the second scroll (4) ( 12) overcomes the pressing force due to the high pressure side acting on
The second scroll (4) is separated from the first scroll (3) by the predetermined gap, and the liquid refrigerant is forcibly discharged through the predetermined gap along with the compression action of each scroll (3) (4). Therefore, liquid compression can be avoided.

As described above, when the differential pressure is low, the second thrust receiving surface (17)
Therefore, the pressure receiving area of the high pressure side pressure receiving surface (12) does not need to be an area capable of obtaining a pressing force that does not cause leakage in the compression element (5) at a low differential pressure. Since the high and low differential pressures can be set to be optimal under normal operating conditions where the differential pressure is high compared to when the differential pressure is low, even if the high and low differential pressure becomes the maximum differential pressure within the operating range, the first thrust The thrust load on the receiving surface (16) can be reduced, the compressor efficiency can be improved, and the reliability of the thrust receiving surface can be improved.

In the embodiment described above, the seal ring (1
Since the low pressure chamber (14) is provided in the outer peripheral region of 1), it is possible to prevent the temperature of the suction gas refrigerant sucked into the compression element (5) from rising during suction.

Although the low pressure chamber (14 is provided by communicating the outer peripheral region of the seal ring (11) with the suction pipe (8), an intermediate pressure is introduced to form an intermediate pressure chamber, and the low pressure side pressure receiving surface (15) Intermediate pressure may be applied to.

Further, although the tip seal (18) is provided on the wrap end surface of the second scroll (4), the tip seal (18) is not always necessary.

(Effects of the Invention) As described above, the present invention internally includes the compression element (5) including the first scroll (3) and the second scroll (4) and the motor (7) in the closed casing (1). In the high pressure dome type scroll compressor in which the discharge pipe (10) is opened in the casing (1), the high pressure side pressure receiving surface (12) and the low pressure side pressure receiving surface (15) are provided on the back surface of the second scroll (4). ) And the pressing force by the high pressure side acting on the high pressure side pressure receiving surface (12) overcomes the separating force by the internal pressure of the compression element (5), the second scroll (4) A first thrust receiving surface (16) for supporting the second scroll receiving surface (16) and a second thrust receiving surface (17) for supporting the second scroll (4) when the separating force overcomes the pressing force. The scroll (4) is attached to the first thrust receiving surface (16) and the second thrust receiving surface (17). While interposing via a predetermined gap between,
The high pressure side receiving surface pressure (12) is based on the surface pressure acting on the first thrust receiving surface (16) during high differential pressure operation in which the differential pressure between the high pressure and the low pressure in the operating range becomes high. Since the pressure receiving area is the pressing force, the first thrust receiving surface (16) thrust-supports when the differential pressure is high, and the second thrust receiving surface (17) supports thrust when the differential pressure is low. The pressing force to be pressed against the first thrust receiving surface (16) at the time of pressure does not need to be set to the pressing force required at the time of low differential pressure, and can be optimized under the normal operating condition of high differential pressure. Therefore, even if the high and low differential pressure becomes the maximum in the operating range, the thrust force will not be too strong and the thrust load will not become excessive. Therefore, the compressor efficiency can be improved and the thrust receiving surface ( The reliability of 16) and 17) can be improved.

Furthermore, the separating force due to the internal pressure of the compression element (5) is
When the pressing force by the high pressure side pressure acting on the high pressure side pressure receiving surface (12) of the scroll (4) is overcome, and when operating under a low differential pressure condition, the first scroll (3) and the second scroll (4) ) With a predetermined gap, the seal of this gap can be sufficiently oil-sealed with the oil injected into the compression element, and a large amount of liquid refrigerant is sucked into the compression element to prevent overcompression. Even if there is a possibility that it will occur, the second scroll (4) is separated from the first scroll (3) by the predetermined gap, and the scrolls (3) and (4) are compressed through the predetermined gap. Since the liquid refrigerant can be forcibly discharged along with the action, liquid compression can also be avoided.

[Brief description of drawings]

FIG. 1 is a partially omitted sectional view showing an embodiment of the compressor of the present invention, FIG. 2 is an enlarged sectional view of a main part, and FIG. 3 is an explanatory view of a conventional example. (1) …… Hermetic casing (3) …… First scroll (4) …… Second scroll (5) …… Compression element (7) …… Motor (9) …… Discharge pipe (12) …… High pressure side Pressure receiving surface (15) …… Low pressure side pressure receiving surface (16) …… First thrust receiving surface (17) …… Second thrust receiving surface

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-2-9973 (JP, A) JP-A-60-204991 (JP, A) JP-A-63-61786 (JP, A) Actual development Sho-62- 173577 (JP, U)

Claims (2)

(57) [Claims] 1. A hermetic casing (1) is internally provided with a compression element (5) having a first scroll (3) and a second scroll (4) and a motor (7), and the casing (1). A high pressure dome type scroll compressor having a discharge pipe (10) opened in a high pressure side pressure receiving surface (1) on the back surface of the second scroll (4).
2) and the low pressure side pressure receiving surface (15) are defined, and the pressing force by the high pressure side pressure acting on the high pressure side pressure receiving surface (12) overcomes the separating force by the internal pressure of the compression element (5). At this time, when the first thrust receiving surface (16) supporting the second scroll (4) and the separating force overcome the pressing force,
A second thrust receiving surface (17) for supporting the second scroll (4) is provided, and the second scroll (4) is provided with the first thrust receiving surface (16) and the second thrust receiving surface (17). While interposing a predetermined clearance between the first thrust receiving surface pressure (12) and the first thrust receiving surface pressure (12) during high differential pressure operation in which the differential pressure between the high pressure and the low pressure in the operating range increases. A high-pressure dome-type scroll compressor characterized by having a pressure-receiving area that serves as a pressing force based on the surface pressure acting on the surface (16). 2. The high pressure dome type scroll compressor according to claim 1, wherein a low pressure is applied to the low pressure side pressure receiving surface (15).