JPH09119389A - Enclosed compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent abnormal increase in discharge pressure with a simple structure and at low cost using high pressure even if the discharge pressure in a casing is increased. SOLUTION: A compression mechanism CF has a relief valve 6 which receives the high pressure of a discharge side and opens an intermediate pressure room 51 during compression to the lower pressure range of a suction side when the high pressure of the discharge side is over the setting pressure. The relief valve 6 has a valve seat on an opening 24 for opening the intermediate pressure room 51 to the suction side and a valve element 7 separating therefrom, an energizing body 9 for energizing the valve element 7 to the valve seat, and a high pressure room 61 for separating the valve element 7 against the energizing body 9 when high pressure is over the setting pressure. The opposite side of the valve seat of the valve element 7 is inserted into a through hole 43 made in a pressure bulkhead which divides a casing 1 into a high pressure side and a low pressure side and it has an opening at the high pressure side and the valve element 7 has a high pressure introducing hole 75 therein which extends to the high pressure room 61 from the end of the opposite side of the valve seat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic compressor mainly used in a refrigerator, an air conditioner or the like and having a casing equipped with a motor and a compression mechanism.

[0002]

2. Description of the Related Art Conventionally, as a hermetic compressor, for example, a casing is provided with a scroll compression mechanism, and one side of the compression mechanism is provided with a high pressure chamber in which a discharge port of the compression mechanism and an external discharge pipe are opened. There is a low pressure dome type scroll compressor in which the suction pipe is opened on the side and a low pressure chamber for arranging the motor is formed. With this structure, if the discharge pressure rises,
Accordingly, the bearing load and the motor torque required for compression increase, and for bearings that support the motor drive shaft, there is a problem that the oil film generated in the bearing becomes thin and the reliability of the bearing decreases. With respect to the above, there was a problem that the reliability of the motor was lowered because the load of the motor increased and the motor temperature increased.

As a measure for solving the problems associated with the increase in bearing load and motor torque under the condition of high discharge pressure, first, the bearing size is increased so that the minimum oil film thickness can be secured. It is conceivable that, as for the motor, it is conceivable to use an efficient and large-sized motor so that the temperature of the motor does not become too high.

However, the larger the size of the bearing and the motor, the higher the cost, and, in the normal operation, the larger size of the bearing, on the contrary, increases the frictional resistance and increases the mechanical loss. It causes a decline in ability.

Therefore, as a method for reducing the bearing load and the motor load under the condition of high discharge pressure, for example, there is a method of controlling the capacity as described in Japanese Patent Laid-Open No. 3-67083.

As shown in FIG. 6, in the scroll compressor capable of controlling the capacity, a compression mechanism CF including a fixed scroll B and an orbiting scroll C is installed in a casing A, and the casing A is fixed. The scroll B is divided into a high pressure chamber D and a low pressure chamber E, a discharge port F provided in the fixed scroll B is opened in the high pressure chamber D, and a discharge pipe G is opened. Although the suction pipe is opened, the low pressure gas sucked from the suction pipe is sucked into the compression mechanism CF and compressed, and then discharged from the discharge port F to the high pressure chamber D.

On the end plate B1 of the fixed scroll B,
A bypass hole J formed between the scrolls B and C, which opens in the middle of the compression stroke of the compression chamber H, and a bypass passage K that connects the bypass hole J to the suction side are formed, and the bypass hole in the end plate B1 is formed. A tubular portion that projects outward in the axial direction is integrally formed at a position facing J, and the tubular portion is a cylinder M that houses an unloader piston L that opens and closes the bypass passage K. Inside the cylinder M, a spring N for urging the piston L in a direction away from the bypass hole J is installed, and the piston L is
In the full load operation, the high pressure for overcoming the urging force of the spring N to seat the piston L in the bypass hole J acts as a back pressure, and in the unload operation, the low pressure acts as a back pressure. By pushing the piston L away from the bypass hole J by the urging force of the spring N and opening the bypass hole J communicating with the compression chamber H to communicate with the low pressure side, the compression operation is performed with a small capacity and the pressure receiving area and pressure are reduced. The gas load is reduced to reduce the bearing load and the motor torque.

[0008]

However, when it is attempted to control the capacity of the scroll compressor to prevent an increase in the discharge pressure, a pressure sensor is installed outside the compressor to detect an abnormal increase in the discharge pressure. It is necessary to connect a pressure introducing pipe P for applying a back pressure to the unloader piston L as shown in FIG. 7, and to select and introduce a high pressure and a low pressure to the pressure introducing pipe P. Therefore, a large number of external parts such as a solenoid valve Q for switching the pressure is required, which not only complicates the piping structure but also raises the cost.

The present invention has been made in view of the above problems. Even if the discharge pressure in the casing rises, the high pressure is utilized to simplify the structure and increase the cost without increasing the cost. An object is to provide a hermetic compressor that can prevent abnormal rise.

[0010]

In order to achieve the above object, the invention according to claim 1 has a casing 1 in which a compression mechanism C is provided.
In the hermetic compressor having the F inside, the compression mechanism CF
Further, the relief valve 6 is provided to open the intermediate pressure chamber 51 in the middle of compression to the low pressure region on the suction side when the high pressure on the discharge side becomes higher than the set pressure and receives the high pressure on the discharge side. .

With the above construction, in the invention according to the first aspect, when the high pressure on the discharge side becomes equal to or higher than the set pressure, the discharged high pressure is directly applied to the relief valve 6 and the intermediate pressure during compression is reached. The pressure chamber 51 is operated so as to be opened to the low pressure region on the suction side, and the unloading operation is performed to prevent the discharge pressure from abnormally increasing. As a result, it is possible to prevent the discharge pressure from abnormally increasing without increasing the size of the motor and the bearings, thus making it possible to prevent the compressor from increasing in size and reduce the cost increase. The performance of can also be improved as compared with the case of enlarging the bearing.

According to a second aspect of the present invention, in the first aspect of the present invention, the compression mechanism CF comprises a fixed scroll 2 and an orbiting scroll 3 that define two symmetrical compression chambers, and a relief valve 6 is provided. Are provided corresponding to the intermediate pressure chambers 51, 51 of the respective systems.

With the above construction, according to the second aspect of the invention, even in the scroll type hermetic compressor having the two systems of compression chambers, the relief valve 6 is associated with the intermediate pressure chambers 51, 51 of the respective systems. Since the above is provided, the abnormal increase of the discharge pressure in each of the intermediate pressure chambers 51, 51 is favorably prevented without disturbing the pressure balance.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the relief valve 6 is seated in and separated from an opening 24 that opens the intermediate pressure chamber 51 to the suction side. And a biasing body 9 for biasing the valve body 7 toward the seating side.
And a high pressure working chamber 61 that separates the valve body 7 against the biasing body 9 when the high pressure exceeds a set pressure.

With the above construction, in the invention according to claim 3, the valve body 7 is provided with a force difference between the urging force of the urging body 9 and the pressure in the high pressure action chamber 61 for introducing the high pressure on the discharge side. Since it is possible to prevent an abnormal rise in discharge pressure with a simple structure that is operated by, it is not necessary to dispose parts outside the compressor in spite of performing capacity control, so the piping structure can be complicated. Also, since the number of parts is not increased, the cost can be reduced.

Further, even when the inside of the compression mechanism CF is in a liquid compression state, the abnormal high pressure of the intermediate pressure chamber 51 causes the valve body 7 to oppose the urging force of the urging body 9 and the intermediate pressure chamber 51 to the suction side. Since it is operated so as to open to the low pressure region of 1, the liquid compression can be avoided.

According to a fourth aspect of the present invention, in the third aspect of the invention, a through hole is provided in the pressure partition wall 4 for partitioning the non-seating side of the valve body 7 into the high pressure side and the low pressure side of the casing 1. Since the end face of the valve body 7 on the side opposite to the seating side is opened to the high pressure side, the high pressure introducing hole 75 extending from the end face on the side opposite to the seating side to the high pressure working chamber 61 is provided inside the valve body 7. is there.

With the above construction, in the invention according to claim 4, the discharge gas discharged to the high pressure side in the casing 1 partitioned by the pressure partition wall 4 is subjected to a high pressure from the high pressure introducing hole 75 formed in the valve body 7. When it is introduced into the chamber 61 and the discharge pressure becomes equal to or higher than the set pressure, that is, when the pressure on the high pressure side in the casing 1 becomes equal to or higher than the set pressure, the high pressure side via the high pressure introduction hole 75. As a result, high-pressure gas having a pressure equal to or higher than the set pressure is introduced into the high-pressure action chamber 61, and the valve body 7 can be easily operated.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. The hermetic compressor of this embodiment is
In the scroll compressor, a compression mechanism CF is provided inside the closed casing 1 and a motor (not shown) is provided below the casing 1, and the compression mechanism CF is
It consists of a fixed scroll 2 and an orbiting scroll 3. The scrolls 2 and 3 are arranged vertically opposite to each other via a frame 11, and the orbiting scroll 3 is interlocked with a drive shaft 12 of the motor, while the casing is also provided. A pressure partition wall 4 for partitioning the interior of the casing 1 into upper and lower parts is provided inside the fixed scroll 2 inside the fixed scroll 2, and a discharge port 22 formed in the fixed scroll 2 is penetrated through the pressure partition wall 4 in the upper side. To form the high pressure chamber 41 on the high pressure side where the external discharge pipe 13 is opened, and at the lower side of the high pressure chamber 41, the suction pipe 14 is opened, and the low pressure for arranging the motor is set. That is, the low-pressure chamber 42 on the side is partitioned and formed.

Therefore, the revolution scroll 3 revolves with respect to the fixed scroll 2 by the rotation of the drive shaft 12 accompanying the drive of the motor, and this revolution drive causes suction from the suction pipe 14 into the low pressure chamber 42. The sucked low pressure gas is sucked into the compression chamber 5 formed by the scrolls 21 and 31 of the scrolls 2 and 3, the sucked gas is compressed, and the compressed gas is discharged from the discharge port 22 to the high pressure. Room 4
1 is discharged to the outside of the casing 1 from the external discharge pipe 13.

In the scroll compressor described above, when the high-pressure pressure on the discharge side becomes equal to or higher than the set pressure in the compression mechanism CF, the high-pressure pressure on the discharge side is received and the intermediate pressure chamber in the middle of compression is being received. The relief valve 6 that opens 51 to the low pressure region on the suction side is provided.

That is, as shown in FIG. 2, the relief valve 6 is provided in the intermediate pressure chambers 51, 51 of the respective symmetrical systems of the compression chamber 5 formed by the fixed scroll 2 and the revolution scroll 3. A pair is provided correspondingly.

The structure of the relief valve 6 will be described in detail. As shown in FIGS. 3 and 4, the intermediate pressure chambers 51, 51 in the end plate 23 of the fixed scroll 2 are shown.
Is opened axially outward at a position corresponding to the relief valve 6
A cylinder 8 for accommodating the valve body 7 is formed. The cylinder 8 has a low-pressure hole portion 81 having a small diameter on the inner bottom side and above the low-pressure hole portion 81 and having a diameter larger than the diameter of the low-pressure hole portion 81. In diameter,
Forming a first step portion 83 into which the first seal ring 82 is press-fitted;
Further, a second step portion 84 having a diameter larger than that of the first step portion 83 is formed above the first step portion 83, and the second step portion 8 is formed.
The second seal ring 85 is press-fitted in the No. 4.

Further, the end plate 23 of the fixed scroll 2 has an opening 24 penetrating the low pressure hole 81 in the cylinder 8 and the intermediate pressure chamber 51, and the low pressure hole 81 has a diameter. The bypass passage 25 that extends in the direction and opens to the outer peripheral surface of the fixed scroll 2 so that the intermediate pressure chamber 51 can be opened to the suction side through the opening port 24, the low pressure hole portion 81, and the bypass passage 25. ing.

The valve body 7 of the relief valve 6 has a small diameter portion 71 which can be inserted into the low pressure hole portion 81 of the cylinder 8 and an outer peripheral surface which is in sliding contact with the inner peripheral surface of the second step portion 84 of the cylinder 8. A large diameter portion 72, and a protrusion 73 extending in the direction opposite to the small diameter portion 71 is formed in the central portion of the large diameter portion 72, and the protrusion 73 is formed in the through hole 43 formed in the pressure partition wall 4. The end surface of the protrusion 73 is inserted through the sealing material 44,
1, and a tapered convex portion 74 that can be seated on and separated from the opening 24 is formed in the central portion of the small diameter portion 71.

When the valve body 7 is inserted into the cylinder 8, the first seal ring 82 is press-fitted into the first step portion 83 of the cylinder 8 and the second seal ring 85 is press-fitted into the second step portion 84 of the cylinder 8. The valve body 7 is inserted into the cylinder 8 and the valve retainer 86 attached to the upper surface of the end plate 23 of the fixed scroll 2 prevents the valve body 7 from popping out.

The valve retainer 86 is formed in an annular shape so that the valve body 7 can move in the axial direction by a predetermined length so as to come into contact with only the outer peripheral portion of the large diameter portion 72. The body 9 is inserted, and the biasing body 9 is sandwiched between the large diameter portion 72 of the valve body 7 and the pressure partition wall 4, and the biasing body 9 is brought into pressure contact with the valve body 7 to open the valve body 7. It is possible to sit on the mouth 24.

Further, the small diameter portion 71 of the valve body 7 and the cylinder 8
The first seal ring 8 disposed between the first stepped portion 83
2 and seals the low pressure hole 81 and the small diameter portion 7 of the valve body 7.
The space formed by 1 and 2 is communicated with the low pressure region through the bypass passage 25, and the high pressure action chamber 61 is formed by the second step portion 84 and the valve body 7 as shown in FIGS. 3 and 4. There is the high pressure chamber 4 in the high pressure working chamber 61.
In order to introduce the high-pressure discharge gas of 1, the L-shaped high pressure that extends from the end face of the projection 73, which is the end face on the non-seating side of the valve body 7 opened to the high pressure chamber 41, into the high pressure action chamber 61 inside the valve body An introduction hole 75 is provided so that the high pressure chamber 41 can pass through the high pressure introduction hole 75.
Is introduced into the high pressure working chamber 61.

Further, in order to move the valve body 7 in the axial direction, as shown in FIG. 5, the valve body 7 acts on the urging force Fs of the urging body 9 and the end face of the projection 73 of the valve body 7. High pressure Hp that acts on the low pressure Lp that acts on the end surface of the large diameter portion 72 of the valve body 7
And the high pressure Hp introduced into the high pressure working chamber 61, the low pressure Lp acting on the end surface of the small diameter portion 71 of the valve body 7, and the upward pressure due to the intermediate pressure Mp act on the high pressure chamber. When the high pressure Hp in 41 is lower than the set pressure, the downward pressure of the valve body 7 overcomes the upward pressure, and when the high pressure Hp in the high pressure chamber 41 is equal to or higher than the set pressure, the valve body 7 so that the upward pressing force of 7 overcomes the downward pressing force, the urging force Fs of the urging body 9, the end surface area D1 of the projection 73, and the end surface area D of the small diameter portion 71.
2. The area D3 of the passage of the opening 24 and the area D4 of the end face of the large diameter portion 72 are set.

When the high pressure discharged to the high pressure chamber 41 is lower than the set pressure, the high pressure working chamber 6
The high-pressure pressure introduced into 1 also becomes lower than the set pressure, and as shown in FIG. 3, the pressure of the high-pressure action chamber 61 is such that the urging force of the urging body 9 and the high-pressure pressure acting on the end surface of the protrusion 73 of the valve body 7 The urging force of the urging body 9 and the protrusion 7 of the valve body 7.
The valve body 7 is pressed downward by high pressure acting on the end surface of the valve 3, and the convex portion 74 of the valve body 7 is seated on the opening 24 to close the opening 24. At this time, the first step portion 8
The high pressure working chamber 61 is sealed by the first seal ring 82 arranged in No. 3 and the second seal ring 85 arranged in the second step portion 84.

When the high pressure discharged to the high pressure chamber 41 exceeds the set pressure, the high pressure above the set pressure is introduced into the high pressure working chamber 61, and as shown in FIG. Pressure becomes larger than the urging force of the urging body 9 and the high pressure acting on the end surface of the protrusion 73 of the valve body 7,
The high pressure of the high pressure action chamber 61 presses the valve body 7 upward to separate the convex portion 74 of the valve body 7 from the opening 24. At this time, the high-pressure action chamber 61 is sealed by the first seal ring 82 and the valve retainer 86, and the intermediate pressure chamber 51 of the compression chamber 5 passes through the open port 24, the low-pressure hole 81, and the bypass passage 25, and the inside of the casing 1. Is opened to the suction side low pressure region.

In the present embodiment, the set high pressure is set to 30K when the low pressure is 6K, the load operation is performed when the low pressure is 29K or less, and the unload operation is performed when 30K or more.

In the above embodiment, the two relief valves 6 are provided so as to correspond to the pair of compression chambers, but they may be provided only in one of the compression chambers. In this case, the pressure balance in the intermediate pressure chamber cannot be maintained, but the discharge pressure can be reduced by the merging of the compressed gas to prevent an abnormal increase in the discharge pressure, and the relief valve can be one, so that the cost can be reduced. Of.

[0034]

According to the first aspect of the invention, when the compression mechanism CF receives a high pressure on the discharge side above a set pressure, it receives the high pressure on the discharge side to generate an intermediate pressure during compression. Since the relief valve 6 that opens the chamber 51 to the low pressure region on the suction side is provided, when the high pressure on the discharge side becomes equal to or higher than the set pressure, the discharged high pressure is directly acted on the relief valve 6 to stop the compression. It is possible to prevent the abnormal increase of the discharge pressure by operating the intermediate pressure chamber 51 to open to the low pressure region on the suction side and performing the unloading operation. As a result, it is possible to prevent the discharge pressure from abnormally increasing without increasing the size of the motor and the bearings, thus making it possible to prevent the compressor from increasing in size and reduce the cost increase. The performance of can also be improved as compared with the case of enlarging the bearing.

According to the second aspect of the present invention, the compression mechanism CF is composed of the fixed scroll 2 and the revolution scroll 3 which define symmetrical two-system compression chambers, and the relief valve 6 is provided.
Since a pair is provided corresponding to the intermediate pressure chambers 51, 51 of the respective systems, even in the scroll type hermetic compressor having the compression chambers of the two systems, the intermediate pressure chambers 51, 51 of the respective systems are associated with each other. Since the relief valve 6 is provided as described above, an abnormal increase in the discharge pressure in each of the intermediate pressure chambers 51, 51 can be favorably prevented without disturbing the pressure balance.

According to the third aspect of the invention, the relief valve 6 opens the intermediate pressure chamber 51 to the suction side.
A valve element 7 which is seated on and away from the valve element, an urging element 9 which urges the valve element 7 toward the seating side, and a valve element 7 which is separated against the urging element 9 when the high pressure exceeds a set pressure. High pressure working chamber 61
Since the valve body 7 is provided with a simple structure in which the valve body 7 is operated by a difference in force between the urging force of the urging body 9 and the pressure in the high pressure action chamber 61 for introducing the high pressure on the discharge side, It is possible to prevent an abnormal rise in pressure, and it is not necessary to dispose parts outside the compressor in spite of performing capacity control, so the piping structure does not become complicated and the number of parts does not increase. Therefore, the cost can be reduced.

Further, even when the inside of the compression mechanism CF is in a liquid compression state, the abnormal high pressure of the intermediate pressure chamber 51 causes the valve body 7 to oppose the urging force of the urging body 9 and the intermediate pressure chamber 51 to the suction side. Since it is operated so as to open to the low pressure region of 1, the liquid compression can be avoided.

According to the invention described in claim 4, the valve body 7
The non-seating side of the valve body 7 is inserted into the through hole 43 provided in the pressure partition wall 4 that divides the inside of the casing 1 into the high pressure side and the low pressure side, and the end face of the valve body 7 on the non-seating side is opened to the high pressure side. , The inside of the valve body 7 from the end surface on the non-seating side to the high pressure working chamber 6
1. Since the high pressure introduction hole 75 extending to 1 is provided, the discharge gas discharged to the high pressure side in the casing 1 partitioned by the pressure partition wall 4 is introduced into the high pressure action chamber 61 from the high pressure introduction hole 75 formed in the valve body 7. Then, when the discharge pressure becomes equal to or higher than the set pressure, that is, when the pressure on the high pressure side in the casing 1 becomes equal to or higher than the set pressure, the pressure higher than the set pressure is supplied from the high pressure side through the high pressure introduction hole 75. The high pressure gas is the high pressure working chamber 61.
The valve body 7 can be easily operated.

[Brief description of the drawings]

FIG. 1 is a partial vertical sectional view showing an embodiment of a hermetic compressor of the present invention.

FIG. 2 is a top view of the fixed scroll in the same embodiment as seen from above, showing a state in which a valve element is inserted into only one cylinder.

FIG. 3 is a cross-sectional view of an essential part of the present invention, showing a load state.

FIG. 4 is a cross-sectional view of a main part of the present invention, showing a state in which an intermediate pressure is communicated with a low pressure side in an unload state.

FIG. 5 is an explanatory view showing a state of pressure acting on the valve body of the relief valve according to the present invention.

FIG. 6 is a partial vertical sectional view showing a conventional scroll compressor.

FIG. 7 is an explanatory diagram showing a state of piping connected to a conventional scroll compressor.

[Explanation of symbols]

 1 Casing CF Compression mechanism 2 Fixed scroll 24 Opening port 3 Revolution scroll 4 Pressure partition wall 43 Through hole 51 Intermediate pressure chamber 6 Relief valve 61 High pressure action chamber 7 Valve body 75 High pressure introduction hole 9 Energizer

Claims (4)

[Claims] 1. A hermetic compressor in which a compression mechanism (CF) is installed in a casing (1), wherein the compression mechanism (CF).
When the high pressure on the discharge side exceeds the set pressure, the high pressure on the discharge side is received and the intermediate pressure chamber (5
A hermetic compressor provided with a relief valve (6) for opening 1) to a low pressure region on the suction side. 2. A compression mechanism (CF) comprises a fixed scroll (2) and an orbiting scroll (3) which define symmetrical two-system compression chambers, and a relief valve (6) comprises an intermediate pressure of each system. The hermetic compressor according to claim 1, wherein a pair is provided so as to correspond to the chambers (51) (51). 3. A relief valve (6) has a valve body (7) which is seated on and away from an opening (24) which opens the intermediate pressure chamber (51) to the suction side, and the valve body (7) is seated on the seating side. And a high pressure action chamber (6) that separates the valve body (7) against the biasing body (9) when the high pressure exceeds a set pressure.
1) The hermetic compressor according to claim 1 or 2, further comprising: 4. A valve body (7) having a non-seating side inserted into a through hole (43) provided in a pressure partition wall (4) for partitioning the inside of the casing (1) into a high pressure side and a low pressure side, While opening the end face of the valve body (7) opposite to the seating side to the high pressure side,
Inside the valve body (7), the high pressure working chamber (6
4. A high pressure introduction hole (75) extending to 1) is provided.
A hermetic compressor as described.