JPH11182464A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a gall by reduction in tip clearance by setting a tooth height of a scroll shorter than other parts in the vicinity of a main flow of bypass gas. SOLUTION: The length, that is, a tooth height of a spiral lap 12 of a fixed scroll 10 and/or a spiral lap 16 of a turning scroll 14 in the vicinity of a main flow of bypass gas, is set shorter than other parts by about 20 μm in advance in an angle range of about 90 deg.. Thus, the occurrence of a gall between the tips of the spiral laps 12 and 16 and end plates 15 and 11 can be prevented since tip clearance in the vicinity of the main flow of the bypass gas can be prevented from becoming smaller than that of the other part at capacity control time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a scroll compressor.

[0002]

2. Description of the Related Art In a conventional capacity control scroll compressor of an internal bypass system, when the capacity is controlled, the temperature of the scroll rises in the vicinity of the main flow of a high-temperature bypass gas, thereby increasing the temperature of the scroll. Since the tooth length is extended, there is a possibility that the tip gap is reduced and galling occurs.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the gist of the present invention is to provide a capacity control scroll compressor of an internal bypass system with a scroll tooth height. A scroll compressor characterized in that it is shorter than the other part in the vicinity of the main flow of the bypass gas.

[0004]

1 to 3 show a preferred embodiment of the present invention. FIG. 1 is a longitudinal sectional view, FIG. 2 is a transverse sectional view taken along line BB of FIG. 1, and FIG. FIG. 5 is a cross-sectional view taken along line CC of FIG.

In FIG. 1, reference numeral 1 denotes a housing, which comprises a cup-shaped main body 2 and a front housing 6 fastened by bolts (not shown). The rotating shaft 7 penetrating the front housing 6 is rotatably supported by the front housing 6 via bearings 8 and 9.

A fixed scroll 1 is provided inside the housing 1.
0, the orbiting scroll 14 and the capacity control block 50 are provided. The fixed scroll 10 includes an end plate 11 and a spiral wrap 12 erected on the inner surface thereof. The orbiting scroll 14 has an end plate 15 and a spiral wrap 16 erected on its inner surface.
And

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 via a slewing bearing 23, and a rotary shaft 7 is provided in a slide groove 24 formed in the drive bush 21.
An eccentric drive pin 25 projecting eccentrically from the inner end of the slidably fitted.

The orbiting scroll 14 and the fixed scroll 10 are mutually eccentric by a predetermined distance as shown in FIG.
The teeth are displaced by 0 °. Thus, as shown in FIG. 1, the tip seal 17 embedded on the distal end face of the spiral wrap 12 is in close contact with the inner surface of the end plate 15, and the tip seal 18 embedded on the distal end face of the spiral wrap 16 is As shown in FIG. 2, a plurality of compression chambers 19a which are in close contact with the inner surface of the end plate 11 and which are in line contact at a plurality of locations and are substantially point-symmetric with respect to the center of the spiral. , 19b are formed.

As shown in FIG. 2, a discharge port 29 is formed in the center of the end plate 11 of the fixed scroll 10, and a pair of bypass ports 33a, 33b communicating with the compression chambers 191a, 19b in the middle of compression. Are drilled.

By arranging the capacity control block 50 close to the outer surface of the end plate 11 of the fixed scroll 10, the recesses 87 and 88 are limited. The fixed scroll is fixed by screwing the tip of a bolt 13 passing through the capacity control block 50 and the cup-shaped main body 2 into the end plate 11 of the fixed scroll 10.
10 and the capacity control block 50 are fastened to the cup-shaped main body 2.

The housing 1 is partitioned by bringing the outer peripheral surface of a flange 51 formed at the outer end of the capacity control block 50 into close contact with the inner peripheral surface of the cup-shaped main body 2.
Is limited to the discharge cavity 31, and the inside of the flange 51 is limited to the low-pressure chamber 28.

As shown in FIG. 3, a discharge hole 53 communicating with the discharge port 29 is formed in the center of the capacity control block 50. The discharge hole 53 is provided with a bolt on the outer surface of the capacity control block 50.
The discharge valve 30 fastened at 36 opens and closes.

A blind hole-shaped cylinder 54 is formed on one side of the discharge hole 53, and a blind hole-shaped cavity 55 is formed on the other side in parallel with the cylinder 54.
Are drilled respectively.

The control pressure chamber 80 is limited at the inner end of the piston 56 and the chamber 81 is limited at the other end by fitting a cup-shaped piston 56 in the cylinder 54 in a slidable manner.
This chamber 81 communicates with the suction chamber 28. And the cylinder
The 54 is provided with a communication hole 92 communicating with the discharge hole 53 and a communication hole 89 communicating with the recess 88.

The piston 56 is pushed toward the control pressure chamber 80 by a coil spring 83 interposed between the piston 56 and a spring receiver 82. An annular concave groove 93 formed in the outer peripheral surface of the piston 56 is always in communication with the chamber 81 via a plurality of holes 94.

On the other hand, a control valve 58 is provided in the cavity 55.
The control valve 58 senses the high pressure in the discharge cavity 31 and the low pressure in the low pressure chamber 28 and generates a control pressure corresponding to these.

As shown in FIG. 1, a thrust bearing 36 and an Oldham link 26 are interposed between the outer peripheral edge of the outer surface of the end plate 15 of the orbiting scroll 14 and the inner end surface of the front housing 6.

A balance weight 27 is fixed to the drive bush 21 and a balance weight 37 is fixed to the rotary shaft 7 in order to balance the dynamic imbalance caused by the revolving orbiting motion of the orbiting scroll 14.

A pipe fitting 40 is fastened to the upper portion of the cup-shaped main body 2 by bolts 41. A gas suction passage 42 and a gas discharge passage 43 are provided between the pipe fitting 40 and the upper outer peripheral surface of the cup-shaped main body 2. Limited.
The gas suction passage 42 communicates with the low-pressure chamber 28 through a gas suction port 44, and the gas discharge passage 43 communicates with the discharge cavity through a hole 45.
It communicates with 31.

When the rotating shaft 7 is rotated during the full load operation, the orbiting scroll 14 is driven via the eccentric drive pin 25, the slide groove 24, the drive bush 21, the orbiting bearing 23, and the boss 20, and the orbiting scroll is rotated. 14 is Oldham Link
The orbital revolving motion is stopped while its rotation is prevented by 26.

Then, the line contact portions on the side surfaces of the spiral wraps 12 and 16 gradually move toward the center of the spiral, and as a result,
The compression chambers 19a and 19b move toward the center of the spiral while reducing their volumes.

Accordingly, the gas sucked into the low-pressure chamber 28 through the gas suction passage 42 and the gas suction port 44 flows from the opening limited by the outer peripheral ends of the spiral wraps 12 and 16 to the compression chambers 19a and 19a. After being taken into the inside 19b and gradually being compressed, it reaches the central chamber 22, through which the discharge valve 29 is pushed through the discharge port 29 and the discharge hole 53 to be discharged to the discharge cavity 31, then the hole 45 and the gas discharge passage. It is discharged to the outside via 43.

During the unload operation of the compressor, the control valve 58 generates a low control pressure. When this control pressure is introduced into the control pressure chamber 80, the piston 56 is pushed by the restoring force of the coil spring 83. It occupies the position shown in FIG.

Thus, the gas being compressed in the compression chambers 19a and 19b enters the chamber 81 via the bypass ports 33a and 33b, the recesses 87 and 88, and the communication hole 89. On the other hand, the compressed gas flows from the center chamber 22 to the discharge port 29, the discharge hole 53, the communication hole 92, the concave groove 93,
These enter the chamber 81 through the hole 94, and merge into the chamber 81, and flow into the low-pressure chamber 28 through the concave groove 84 formed by cutting out the outer peripheral surface of the end plate 11 of the fixed scroll 10.

During the full load operation of the compressor, the control valve 58 generates a high control pressure. When the high control pressure enters the control pressure chamber 80, the piston 56 resists the elastic force of the coil spring 83. And the outer end of the spring
Since the contact holes 82 are in contact with each other, both the communication hole 89 and the communication hole 92 are closed by the piston 56.

When the capacity of the compressor is reduced, a control pressure corresponding to the reduction rate is generated at the control valve 58. When this control pressure acts on the inner end face of the piston 56 via the control pressure chamber 80, the piston 56 stops at a position where the pressing force due to the control pressure and the elastic force of the coil spring 83 are balanced.

Accordingly, while the control pressure is low, only the communication hole 89 is opened, and the gas being compressed in the compression chambers 19a and 19b is discharged into the low-pressure chamber 28 by an amount corresponding to the degree of opening of the communication hole 89.
Further, as the control pressure increases, the communication hole 92 opens, and when the opening degree increases and the communication hole 92 is fully opened, the capacity of the compressor becomes zero.

During unload operation, that is, during capacity control, high-temperature bypass gas passes through the chamber 81 of the cylinder 56 and passes through the low-pressure chamber 28.
Since the temperature of the spiral wraps 12 and 16 near the main flow of the bypass gas rises and thermally expands, the gap between the front end and the inner surfaces of the end plates 15 and 11, that is, the chip gap, It is smaller than that of other parts.

Therefore, in the present invention, the length of the spiral wrap 12 of the fixed scroll 10 or the spiral wrap 16 of the orbiting scroll 14 near the main flow of the bypass gas, that is, the tooth height of about 90 ° is used. Within the angle range 20 times more than the other parts in advance
μ is shortened.

Thus, at the time of capacity control, it is possible to prevent the tip gap near the main flow of the bypass gas from becoming smaller than that of the other parts, so that the tips of the spiral wraps 12, 16 and the inner surfaces of the end plates 15, 11 can be prevented. This can prevent galling from occurring.

[0031]

According to the present invention, since the tooth length of the scroll is made shorter in the vicinity of the main flow of the bypass gas than in other portions, it is possible to prevent the chip gap near the main flow of the bypass gas from becoming small during capacity control. Therefore, galling can be prevented from occurring between the tip of the spiral wrap and the inner surface of the end plate.

[Brief description of the drawings]

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

FIG. 2 is a transverse sectional view taken along line BB of FIG.

FIG. 3 is a transverse sectional view taken along line CC of FIG. 1;

[Explanation of symbols]

 1 Housing 28 Low-pressure chamber 31 Discharge cavity 44 Gas inlet 10 Fixed scroll 11 End plate 12 Spiral wrap 14 Orbiting scroll 15 End plate 16 Spiral wrap 50 Capacity control block 54 Cylinder 56 Piston 19a, 19b Compression chamber 33a, 33b Bypass port

Claims (1)

[Claims] 1. A scroll compressor according to claim 1, wherein the length of the scroll is shorter in the vicinity of the main flow of bypass gas than in other portions.