JPH0932782A - Capacity controller for scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stop leakage of compressed gas on the way of compression when a bypass piston is seated on a spring washer, by covering front surfaces of the spring washer and a snap ring with rubber. SOLUTION: In the full-load operation, a bypass piston 56 is moved leftward, and the left end of the bypass piston 56 is seated on the right end surface of a spring washer 82. The left end surface of the spring washer 82 is brought in contact with the right end surface of a snap ring 102, the left end surface of the snap ring 102 is brought in contact with the left end surface of a ring groove 107, and a clearance is sealed by rubber GF for covering the front surfaces of the spring washer 82 and the snap ring 102. Compressed gas on the way of compression, allowed to flow from communication holes 89a, 89b through the clearance 106 between the outer peripheral surface of the bypass piston 56 and the inner peripheral surface of a cylinder 54 does not leak from the clearances among respective end surfaces of the bypass piston 56, the spring washer 82, the snap ring 102, and the ring groove 105.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacity control device for a scroll compressor incorporated in an air conditioner or the like.

[0002]

2. Description of the Related Art One example of a conventional scroll compressor is shown in FIGS. In FIG. 4, reference numeral 1 denotes a closed housing, which is composed of a cup-shaped main body 2 and a front case 6 fastened to the cup-shaped main body 2 by bolts (not shown). A main shaft 7 that penetrates through the front case 6 and extends into the closed housing 1 is provided with bearings 8 and 9 and is attached to the front case 6.
It is rotatably supported by.

A fixed scroll 10 is provided in a closed housing 1.
And an orbiting scroll 14 are provided. The fixed scroll 10 has an end plate 11 and a spiral wrap 12 erected on its inner surface.
And The orbiting scroll 14 includes an end plate 15 and a spiral wrap 16 erected on the inner surface thereof, and the spiral wrap 16 has substantially the same shape as the spiral wrap 12 of the fixed scroll 10. ing.

The orbiting scroll 14 and the fixed scroll 10 are eccentric to each other by the orbiting orbiting radius, and are meshed with each other at an angle of 180 ° as shown in the figure. Thus, the tip surface of the spiral wrap 12 is in close contact with the inner surface of the end plate 15, the tip surface of the spiral wrap 16 is in close contact with the inner surface of the end plate 11, and the side surfaces of the spiral wraps 12 and 16 are plural. A plurality of compression chambers 19a that come into line contact with each other at points and are substantially point-symmetric with respect to the center of the spiral.
, 19b are formed.

A drive bush 21 is provided inside a cylindrical boss 20 projecting from the center of the outer surface of the end plate 15 of the orbiting scroll 14.
Is rotatably fitted through a slewing bearing 23, and an eccentric pin 25 eccentrically provided on the inner end of the main shaft 7 is fitted in a hole formed in the drive bush 21.

A discharge port 29 is bored in the center of the end plate 11 of the fixed scroll 10 and communicates with the compression chambers 19a, 19 in the middle of compression at positions symmetrical with respect to the discharge port 29. A pair of bypass ports 33a and 33b are provided.

The capacity control block 50 is arranged so as to be in close contact with the outer surface of the end plate 11 of the fixed scroll 10, and the bolt 13 is formed in the bolt hole 3 formed in the cup-shaped body 2 and the capacity control block 50. The capacity control block 50 and the fixed scroll 10 are fixed to the cup-shaped main body 2 by penetrating the bolt hole 52 and screwing the tip thereof into the fixed scroll 10.

A seal member 5 such as an O-ring is embedded in a seal groove 4 formed on the outer peripheral surface of the capacity control block 50, and the seal member 5 is hermetically sealed on the inner peripheral surface of the cup-shaped main body 2. The inside of the hermetically sealed housing 1 is partitioned into a suction chamber 28 and a discharge cavity 31 by closely contacting with.

A discharge hole 53 communicating with the discharge port 29 is bored in the center of the capacity control block 50. The discharge hole 53 is provided on the rear surface of the capacity control block 50 together with the retainer 35 and the bolt 36.
It is adapted to be opened and closed by the discharge valve 30 fastened at.

As shown in FIGS. 5 and 6, a blind hole-shaped cylinder 54 is provided on one side of the discharge hole 53, and a cylinder 54 is formed on the other side.
A tapered cavity 55 is drilled in parallel with the cylinder 54.
And the rear end opening of the cavity 55 communicates with the suction chamber 28.

In the cylinder 54, as clearly shown in FIG.
The bypass piston 56 is built in via the piston rings 103 and 104 in a sealed and slidable manner.
The control pressure chamber 80 is limited to one side of the chamber and the chamber 81 is limited to the other side.
Communicates with the suction chamber 28. The bypass piston 56 is pushed toward the bottom of the cylinder 54 by the spring 83 interposed between the bypass piston 56 and the spring washer 82.

The spring washer 82 is fixed to the cylinder 54 by a snap ring 102 fitted in a ring groove 107 and set in the cylinder 54. The annular recessed groove 93 formed in the outer peripheral surface of the piston 56 is always communicated with the chamber 105 in the bypass piston 56 through the plurality of holes 94.

On the other hand, as shown in FIG. 5, a control valve 58 is fitted in the cavity 55, and a gap between the cavity 55 and the control valve 58 is provided along the outer peripheral surface of the control valve 58 along the axial direction. Atmospheric pressure chamber 6 by dividing by a plurality of O-rings 59, 60, 61, 62 installed with a gap
3. The low pressure chamber 64, the control pressure chamber 65 and the high pressure chamber 66 are limited.

The atmospheric pressure chamber 63 communicates with the atmosphere outside the housing 1 through a through hole 67 and a pressure guiding tube (not shown). Low pressure chamber 64
Is communicated with the suction chamber 28 through the through hole 68, and the control pressure chamber 65 is through the through hole 6
The control pressure chamber 80 communicates with the concave groove 70 and the through hole 71 shown in FIGS. 9, 8 and 9, and the high pressure chamber 66 communicates with the discharge cavity 31 through the through hole 72.

The control valve 58 has a discharge cavity 31.
It detects the high pressure HP inside the chamber and the low pressure LP inside the suction chamber 28, and generates a corresponding control pressure AP. As shown in FIGS. 8 and 9, a concave groove 7 is formed on the inner surface of the capacity control block 50.
0, 90, 91, first recess 86, second recess 87, third recess 8
8 is provided, and a seal groove 84 is provided in a land portion 57 surrounding these recesses 86, 87, 88.

A seal material 85 fitted in the seal groove 84
By closely contacting the outer surface of the end plate 11 of the fixed scroll 10, these first, second and third recesses 86, 87, 88 are sealed between the capacity control block 50 and the outer surface of the end plate 11. Moreover, it is partitioned by the sealing material 85.

The first recess 86 communicates with the control pressure chambers 65 and 80 through the through holes 69 and 71, and the second recess 87 through the bypass ports 33a and 33b formed in the end plate 11. Compression chamber during compression
19a, 19b and open to the cylinder 54 through the communication holes 89a, 89b. The third recess 88 communicates with the discharge hole 53 through the recess groove 90 and through the recess groove 91 and the communication hole 92. Communicating with the cylinder 54.

Therefore, the bypass ports 33a and 33b, the second recess 87, the communication holes 89a and 89b, the cylinder 54, and the chamber 81 communicate with the suction chamber 28 through a bypass passage.

The bypass ports 33a and 33b are compression chambers.
19a and 19b are placed in positions where they communicate with the compression chambers 19a and 19b until the compression stroke is completed and the volume of the gas is reduced to 50%.

Further, in FIG. 4, 24 is a thrust bearing,
26 is a rotation prevention mechanism such as Oldham link, 27 is a balance weight attached to the drive bush 21, 95
Is a chamber block, 100 is a balance weight attached to the main shaft 7, and 101 is a gas passage formed in the front case 6 so as to face the intake gas passage 99.

When the main shaft 7 is rotated, the orbiting scroll 14 is driven by the orbiting drive mechanism including the eccentric pin 25, the drive bush 21, the orbiting bearing 23, the boss 20, etc., and the orbiting scroll 14 is a rotation preventing mechanism. While being prevented from rotating by 26, the revolution radius, that is, the main shaft 7 and the eccentric pin
When the amount of eccentricity with 25 is taken as the radius, the orbital motion revolves on a circular orbit.

Then, the line contact portions of the spiral wraps 12 and 16 gradually move toward the center of the spiral, and as a result, the compression chamber
19a and 19b move toward the center of the spiral while reducing their volume. Along with this, the gas flows into the suction chamber 28 through the suction chamber 97 and the suction gas passage 99, and the spiral wrap.
It is taken into the compression chambers 19a, 19b from the outer end openings of 12 and 16 and is compressed while reaching the center. From here, the discharge valve 30 is pushed through the discharge port 29 and the discharge hole 53 to the discharge cavity 31. It is discharged and then discharged to the outside through the discharge gas passage 98 and the discharge chamber 96.

During the unloading operation of the compressor, the control pressure AP generated by the control valve 58 decreases. When this control pressure AP is introduced into the control pressure chamber 80 through the through hole 69, the concave groove 70, and the through hole 71, the bypass piston 56 is pushed by the restoring force of the spring 83 and occupies the position shown in FIG.

Thus, the communication holes 89a and 89b are opened,
Since the communication hole 92 communicates with the concave groove 93, the gas which is being compressed in the compression chambers 19a and 19b enters the chamber 81 through the bypass ports 33a and 33b, the second recess 87, and the communication holes 89a and 89b. . On the other hand, the compressed gas that came to the center of the vortex is the discharge port 29,
Discharge hole 53, third recess 88, recessed grooves 90, 91, communication hole 92, recessed groove
Since it enters the chamber 107 through the holes 93 and 94 and joins in the chamber 81 and is discharged to the suction chamber 28, the capacity of the compressor becomes zero.

During full load operation of the compressor, the control valve 58 generates a high control pressure AP. Then
This high control pressure AP enters the control pressure chamber 80 and the piston
Press the 56 inner end face. Thus, the piston 56 has a spring 83
Of the spring washer 82, that is, the position shown in FIG.

In this state, the communication holes 89a, 89b and the communication holes
Since 92 is closed by the bypass piston 56, all the gas that has been compressed in the compression chambers 19a and 19b and has come to the center of the vortex passes through the discharge port 29 and the discharge hole 53, and the discharge valve
It pushes open 30 and is discharged into the discharge cavity 31, maximizing the capacity of the compressor.

When reducing the capacity of the compressor, a control pressure AP corresponding to the reduction rate is generated in the control valve 58. When the control pressure AP acts on the inner end surface of the piston 56 via the control pressure chamber 80, the bypass piston 56 is stopped at a position where the pressing force by the control pressure AP and the elastic force of the spring 83 are balanced.

Therefore, the communication hole 89a is provided while the control pressure AP is low.
, 89b are opened, and the gas being compressed in the compression chambers 19a, 19b is discharged into the suction chamber 28 by an amount corresponding to the opening of the communication holes 89a, 89b, and the control pressure AP rises to increase the communication hole 89a, 89
When b is fully open, the compressor capacity is reduced to 50%. Further, when the control pressure AP rises, the communication hole 92 is opened, and when it is fully opened, the capacity of the compressor becomes zero. In this way, compressor capacity varies from 0% to 100%.

[0029]

In the above conventional device, as shown in FIG. 12, the length of the bypass piston 56,
The sizes and positions of the communication holes 89a, 89b, 92, 94 and the widths and positions of the piston rings 103, 104 are uniquely determined by the size of the capacity control block 50 and the opening / closing timing of the communication holes 89a, 89b, 92, 94.

Therefore, the spring washer 82 is inserted from the communication holes 89a and 89b.
The dimension L to the right end surface of the
The compressed gas in the middle of the compression passes from the communication holes 89a and 89 to the gap 106 between the outer peripheral surface of the bypass piston 56 and the inner peripheral surface of the cylinder 54, the gap between the spring washer 82 and the snap ring 102 and the inner peripheral surface of the cylinder 54, and the spring washer. There was a risk of leaking into the chamber 81 through the gap between the 82 and the snap ring 102 and reducing the performance of the compressor.

To address this, the bypass piston 56
It was proposed to insert a piston ring on the outer peripheral surface of the left end part of the, but in order to maintain the durability of this piston ring, it is necessary to make it wider than the width of the communication holes 89a, 89b. Since L is short, it is impossible due to layout restrictions.

[0032]

SUMMARY OF THE INVENTION The present invention has been invented to solve the above problems, and is characterized by the first aspect of the invention in which the surfaces of the spring washer and the snap ring are coated with rubber. Especially. Thus, in the first aspect of the present invention, when the bypass piston is seated on the spring washer, leakage of compressed gas during compression is prevented by the rubber on the surface of the spring washer and the snap ring.

The rubber can be composed of H-NBR which is durable to the R134a refrigerant.

The feature of the second invention resides in that rubber is attached to the end surface of the bypass piston on the side where the spring washer is seated.

According to the second aspect of the invention, however, when the bypass piston is seated on the spring washer, the rubber attached to the bypass piston comes into close contact with the spring washer to prevent leakage of compressed gas during compression.

[0036]

DETAILED DESCRIPTION OF THE INVENTION One embodiment of the present invention is shown in FIG. The surfaces of the spring washer 82 and the snap ring 102 are covered with rubber GF. If this rubber GF is made of H-NBR, which has durability against R134a refrigerant, R134a
When the refrigerant is compressed, its durability can be improved. Other configurations are the same as those of the conventional one shown in FIGS. 4 to 12,
Corresponding members have the same reference characters allotted.

During full load operation, however, the bypass piston 56 moves to the left and occupies the position shown in the figure, and the left end of the bypass piston 56 is seated on the right end surface of the spring washer 82. Then, the left end surface of the spring washer 82 abuts on the right end surface of the snap ring 102, and the left end surface of the snap ring 102 contacts the ring groove 10.
7 is abutted on the left side surface, and these gaps are sealed by the rubber washer GF covering the surfaces of the spring washer 82 and the snap ring 102.

Thus, the gap 106 between the outer peripheral surface of the bypass piston 56 and the inner peripheral surface of the cylinder 54 is formed from the communication holes 89a and 89b.
Compressed gas that has passed through the compressor is bypass piston 56
Between the left end face of the spring washer 82 and the right end face of the spring washer 82, the left end face of the spring washer 82 and the right end face of the snap ring 102, and the left end face of the snap ring 102 and the left side face of the ring groove 105. There is no.

During the unload operation, the bypass piston 56 moves to the right and its left end face separates from the right end face of the spring washer 82. Therefore, the compressed gas in the middle of compression is the same as the conventional one. Leakage occurs from the gap between the left end face and the right end face of the spring washer 82, the gap between the left end face of the spring washer 82 and the right end face of the snap ring 102, and the gap between the left end face of the snap ring 102 and the left side wall of the ring groove 107. Since the capacity of the compressor is surplus during the unload operation, this gas leakage does not have any adverse effect on the performance of the compressor.

A second embodiment of the present invention is shown in FIG. In the second embodiment, as shown in FIG. 2 (A), a rubber 130 is adhered to the left end surface of the bypass piston 56 by an adhesive, and the left end of the rubber 130 becomes thinner toward the outer peripheral side. The protrusion 130a is formed.

When the bypass piston 56 is seated on the spring washer 52 during full load operation, the protrusion 130a of the rubber 130 is deformed and the tip of the protrusion 130 protrudes in the circumferential direction, as shown in FIG. 2 (B). Outer peripheral surface of bypass piston 56 and cylinder
Seal the gap between the inner surface of 54.

As shown in FIG. 3, the rubber 131 has protrusions.
131a, 131b are provided, the projection 131a is fitted and inserted in the concave groove formed in the inner peripheral surface of the bypass piston 56, and the projection 131b is fitted and inserted in the concave groove formed in the outer peripheral surface of the bypass piston 56, The elastic force of the rubber 131 may be used to fix the rubber 131 to the bypass piston 56.

[0043]

According to the first aspect of the invention, since the surfaces of the spring washer and the snap ring are coated with rubber, when the bypass piston is seated by the bypass piston during full load operation, the spring washer contacts the snap ring and the snap ring. Abut the ring groove, and these gaps are sealed by the rubber covering the surface of the spring washer 82 and the snap ring.

Thus, the compressed gas in the middle of compression that has passed through the gap between the outer peripheral surface of the bypass piston and the inner peripheral surface of the cylinder has a gap between the bypass piston and the spring washer, a gap between the spring washer and the snap ring, and a snap ring. Since it does not leak from the gap between the ring groove and the ring groove, the performance of the compressor during full load operation can be improved.

If the rubber is made of H-NBR having durability against the R134a refrigerant, the durability of the scroll compressor for compressing the R134a refrigerant gas can be improved.

If a rubber is attached to the end face of the bypass piston on the side where the spring washer is seated, when the bypass piston is seated on the spring washer during full load operation, the rubber seals the gap between the bypass piston and the spring washer. You can

When the bypass piston is seated on the spring washer and the tip of the rubber is made to protrude in the circumferential direction, the gap between the outer peripheral surface of the bypass piston and the inner peripheral surface of the cylinder is formed by the tip of the rubber. Can be sealed.

[Brief description of drawings]

1A and 1B show a first embodiment of the present invention, in which FIG. 1A is a longitudinal sectional view, FIG. 1B is a perspective view of a spring washer, and FIG. 1C is a perspective view of a snap ring.

FIG. 2 shows a second embodiment of the present invention, in which (A) is a state in which the bypass piston is separated from the spring washer, and (B) is a longitudinal sectional view showing a state in which the bypass piston is seated on the spring washer. Is.

FIG. 3 shows a third embodiment of the present invention, (A) is a longitudinal sectional view, and (B) is a perspective view of rubber.

FIG. 4 is a vertical sectional view of a conventional scroll compressor.

5 is a cross-sectional view taken along the line DD of FIG.

6 is a cross-sectional view taken along the line EE of FIG.

7 is a view taken along the arrow F of FIG.

FIG. 8 is a view taken along the line BB in FIG.

9 is a perspective view taken along the line EE of FIG.

10 is a cross-sectional view taken along the line AA of FIG. 7.

11 is a cross-sectional view taken along the line GG in FIG. 7.

FIG. 12 is an enlarged vertical sectional view of the capacity control device.

[Explanation of symbols]

 54 Cylinder 58 Control valve 83 Spring 82 Spring washer 102 Snap ring 89a, 89b Bypass passage 81 Suction chamber GF Rubber

Claims (4)

[Claims] 1. A fixed scroll and an orbiting scroll, each of which has a spiral wrap erected on an end plate, are meshed with each other to form a compression chamber between the scrolls, and the orbiting scroll is provided to the fixed scroll. A gas is sucked from the suction chamber into the compression chamber by the orbiting motion, and the compressed gas is discharged from the discharge port provided at the center of the end plate of the fixed scroll, and compressed to the end plate of the fixed scroll. A bypass port communicating with a compression chamber in the middle is provided, a bypass passage communicating this bypass port with the suction chamber, a cylinder having the bypass passage opened, and a slidable fit in the cylinder to open the opening. A bypass piston that opens and closes, a spring that biases the bypass piston in one direction, and a spring that is installed in the cylinder to support the spring. In addition, in a scroll compressor having a spring washer on which the bypass piston is seated, and a capacity control device including a snap ring for fixing the spring washer to the cylinder, the surface of the spring washer and the snap ring is coated with rubber. A capacity control device for a scroll compressor characterized in that 2. The capacity control device for a scroll compressor according to claim 1, wherein the rubber is made of H-NBR having durability against a R134a refrigerant. 3. A fixed scroll and an orbiting scroll, each of which has a spiral wrap provided upright on the end plate, are meshed with each other to form a compression chamber between the scrolls, and the orbiting scroll is revolved around the fixed scroll. By moving the suction chamber, the compressed gas is sucked into the compression chamber, and the compressed gas is discharged from the discharge hole provided in the center of the end plate of the fixed scroll. A bypass passage communicating with the suction chamber, a cylinder having the bypass passage opened, and a bypass piston slidably fitted in the cylinder to open and close the opening. A spring for urging the bypass piston in one direction, and a spring installed in the cylinder for supporting the spring and A scroll compressor provided with a capacity control device comprising a spring washer on which a bypass piston is seated, wherein a rubber is attached to an end surface of the bypass piston on the seating side of the spring washer. 4. A displacement control device for a scroll compressor, characterized in that when the bypass piston is seated on the spring washer, the tip end portion of the rubber can be pushed out in the circumferential direction.