JPH11236888A - Scroll compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessive compression by providing a second delivery port making contact with the outside surface opposite to the delivery port of the lap tip of a fixed scroll to the position corresponding to the position where one side of a pair of compression rooms nearest to the delivery port is communicated with the delivery room through the delivery port and communicating the other side with the delivery port nearly simultaneously. SOLUTION: The relation between a pair of compression rooms 12a, 12b nearest to a delivery port 15 and the delivery port 15, a second delivery port 15a is changed for the turning of a turning scroll 5. The second delivery port 15a is provided on the position corresponding to the position where one side compression room 12a of a pair of compression rooms 12a, 12b is communication with a delivery room 19 through the delivery port 15 and communication the other compression room 12b with the delivery room 19 nearly simultaneously. The diameter of the second delivery port 15a is formed equal or smaller to the thickness of the lap 4b on the part in which the outside surface of the lap 4b of a fixed scroll 4 is an involute curve and to larger than the clearance between the lap 4b tip of the fixed scroll 4 and the outside surface of the lap 5b of the turning scroll 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scroll compressor, and more particularly, to a pressure balance device for a pair of compression chambers.

[0002]

2. Description of the Related Art FIG. 6 is a longitudinal sectional view showing the structure of a conventional scroll compressor, and FIG. 7 is a plan view (A) of a fixed scroll of the conventional scroll compressor, showing a fixed scroll and a lead. The exploded perspective view (B) of a valve is shown. A conventional scroll compressor will be described with reference to FIGS.

[0003] The scroll compressor includes a compressor 2 and an electric motor 3 inside a sealed container 1. The compression section 2 is mainly composed of a fixed scroll 4, an orbiting scroll 5, a rotation preventing device, an orbiting drive shaft 7, a crankshaft 8, a main bearing 9, a metal bearing 10, and a shaft 11.

[0004] The compression section 2 is composed of a fixed scroll 4 having a spiral wrap 4b on a head plate 4a and a head plate 5a.
And a plurality of compression chambers 12, 12a, 12
An orbiting scroll 5 for forming b or the like is provided. Further, a shaft 11 for supporting the orbiting drive shaft 5c of the orbiting scroll 5 and forming a crankshaft 8 at the lower end for orbiting driving, a bearing 7 for supporting the crankshaft 8 and a center of the bottom surface of the fixed scroll 4 And a discharge port 15 which communicates with the central compression chamber 12 formed at the center.

In this configuration, when the shaft 11 is rotated by the rotation of the electric motor 3, the orbiting scroll 5 makes a revolving motion with respect to the fixed scroll 4 without rotating by the anti-rotation device, and the fixed scroll 4 and the orbiting scroll 5 mesh with each other. A pair of compression chambers 12 formed by
a and 12b sequentially move from the outer peripheral part to the central part, and the intake pipe 1
3, the volume of the refrigerant gas taken into the intake chamber 14 is reduced, and a compression action occurs. The compressed gas of the refrigerant enters the motor room 17 from the discharge port 15 provided at the center of the fixed scroll 4 through the communication path 16, and is guided to the outside through the discharge pipe 18.

By the way, the outer surface of the tip of the wraps 4a, 5a on the side of the discharge port 15 is formed not in an involute curve but in an arc shape, and the pair of compression chambers 12a, 12b
Immediately after the start of discharge, the discharge port 14 is opened only in one compression chamber 12a, and the other compression chamber 12b is provided between the tip of the wrap 4b of the fixed scroll 4 and the outer surface of the wrap 5b of the orbiting scroll 5. Refrigerant gas flows only from the gap.

In such a structure, the gap is small and the flow path resistance is large, so that the pressure in the compression chamber 12b is higher than that in the compression chamber 12a. For this reason, the pair of compression chambers 12a, 12
As for b, pressure imbalance occurs and there is a risk of overcompression.
Since the scroll compressor is a fixed displacement compressor in which the ratio between the suction volume and the compression completion state is constant, when the scroll compressor is operated at a pressure ratio smaller than the set pressure ratio, the pressure in the compression chamber 12 becomes higher than the discharge pressure. This causes a phenomenon of overcompression, which requires extra power for the compressor.

On the other hand, when the gap is increased, the thickness of the tip of the wrap 4b is reduced and the strength is reduced. As described above, the conventional scroll compressor has a problem that the compression efficiency and reliability may be reduced as described above.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention balances the pressure of a pair of compression chambers without reducing the wrap strength, reduces the flow path resistance and reduces overcompression. It is an object of the present invention to provide a scroll compressor that prevents the above problem.

[0010]

According to the present invention, a compressor and an electric motor are arranged in a sealed container, and the compressor is engaged with a fixed scroll having a spiral wrap and the fixed scroll. A swirl scroll having a spiral wrap and forming a plurality of pairs of compression chambers; and a shaft which supports a swivel drive shaft of the swirl scroll and forms a crankshaft at an upper end thereof and revolves. A scroll compressor comprising: a main bearing that supports the crankshaft; and a discharge port provided in the center of the fixed scroll, and a compression chamber and a discharge chamber having a normal discharge pressure near the discharge port. A position in which one of a pair of compression chambers closest to the discharge port corresponds to a position communicating with the discharge chamber through the discharge port, and a position in which the other compression chamber communicates with the discharge chamber almost simultaneously, and the fixed scroll. Outside of the wrap A second discharge port is provided between the end surface of the fixed scroll and the rear surface between the position which is the start point of the involute curve and the wrap tip, and which is in contact with the outer surface opposite to the discharge port of the wrap tip portion of the fixed scroll. To be.

Further, the diameter of the second discharge port is set to be equal to or smaller than the thickness of the wrap at a portion where the outer surface of the wrap of the fixed scroll has an involute curve.

The diameter of the second discharge port is made larger than the gap between the tip of the wrap of the fixed scroll and the outer surface of the wrap of the orbiting scroll.

On the other hand, a discharge valve for closing both the discharge port and the second discharge port is provided on the back side of the fixed scroll. Further, the discharge valve is a reed valve.

The reed valve is mounted on a straight line connecting the discharge port and the second discharge port, and a fulcrum is provided at an end of the reed valve on the discharge port side. Further, the length from the fulcrum of the reed valve is set to a length corresponding to the operating pressure difference between the discharge port to which the reed valve is mounted and the second discharge port.

Alternatively, the reed valve is mounted substantially at right angles to a straight line connecting the discharge port and the second discharge port, and a fulcrum is provided at an end of the reed valve.

The reed valve is provided for each of the discharge port and the second discharge port, and has the same length from the fulcrum of the reed valve to the discharge port and the second discharge port. Length.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail based on embodiments with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view showing the structure of the scroll compressor of the present invention, and FIG.
FIGS. 3A to 3L are explanatory views showing a state accompanying the turning motion of the scroll compressor according to the first embodiment of the present invention, FIG. 3 is an enlarged view of a main part in FIG. 2E, and FIG. 1A shows a plan view of a fixed scroll of a scroll compressor according to a first embodiment of the present invention, and FIG. Hereinafter, a first embodiment of the present invention will be described. Other than the basic configuration of the present embodiment, the configuration is the same as that of the conventional example shown in FIG. The same numbers are used for the same components.

A compression unit 2 and an electric motor 3 are vertically arranged in a sealed container 1.
And a plurality of pairs of compression chambers 12 having a spiral scroll wrap 4b and a fixed scroll 4 having a spiral wrap 4b and a spiral wrap 5b interlocking with the fixed scroll 4. , A rotating shaft 5 supporting the rotating drive shaft 7 of the rotating scroll 5 and forming a crankshaft 8 at an upper end thereof for revolving motion.
And a main bearing 9 that supports the crankshaft 8 to form a scroll compressor.

A discharge port 15 is provided at the center of the fixed scroll 4 and the compression chambers 12 and 1 are provided near the discharge port 15.
Discharge chambers 2a and 12b and a normal discharge pressure are provided.

Here, according to the present invention, the second discharge port 15a, which is in contact with the outer surface of the wrap 5b of the fixed scroll 4 opposite to the discharge port 15, is connected to a pair of compression chambers 12a closest to the discharge port 15. , 12b correspond to a position communicating with the discharge chamber 19 through the discharge port 15, and the other compression chamber 12b communicates with the discharge chamber 19 almost simultaneously, and the end plate 4a of the fixed scroll 4
And between the back. In this embodiment, in order to satisfy the above-mentioned condition, the second discharge port 15a is provided between the position where the outer surface of the wrap 4b of the fixed scroll 4 becomes the starting point 4b1 of the involute curve and the tip of the wrap 4b. . Further, the diameter of the second discharge port 15a is equal to or smaller than the thickness of the wrap 4b in a portion where the outer surface of the wrap 4b of the fixed scroll 4 is an involute curve, and the wrap 4b of the fixed scroll 4 is formed. It is formed larger than the gap s between the tip and the outer surface of the wrap 5b of the revolving scroll 5.

On the other hand, on the back side of the fixed scroll 4, a reed valve 20 as a discharge valve for closing both the discharge port 15 and the second discharge port 15a, and the discharge port 15 and the second discharge port 15a are provided. Attach on a straight line that connects
In order to provide “a” at the end of the reed valve 20 on the discharge port 15 side, it is fixed with a screw. Further, the length from the fulcrum 20a of the reed valve 20 is x to the discharge port 15, respectively.
Assuming that y is up to the second discharge port 15a, and that the operating pressures of the discharge port 15 and the second discharge port 15a to which the reed valve 20 is attached are p1 and p2, x * is based on the fulcrum 20a. The length is set to correspond to the operating pressure difference so that p1 = y * p2.

Next, the operation of the present invention will be described.
As shown in FIGS. 2A to 2L, the orbiting scroll 5
The relationship between the pair of compression chambers 12a and 12b closest to the discharge port 15 and the relation between the discharge port 15 and the second discharge port 15a sequentially changes, and a series of operations is repeated. Then, referring to FIG. 3, which is an enlarged view of a main part of FIG. 2E, one of the pair of compression chambers 12a, 12b corresponds to a position where one of the compression chambers 12a and 12b communicates with the discharge chamber 19 through the discharge port 15, and the other. The second discharge port 15a is provided at a position where the compression chamber 12b communicates with the discharge chamber 19 at substantially the same time, so that the discharge start timings substantially coincide. For this reason, the pressures in the pair of compression chambers 12a and 12b are balanced.

The diameter of the second discharge port 15a is
Since the outer surface of the wrap 4b of the fixed scroll 4 is equal to or smaller than the thickness of the wrap 4b in a portion where the wrap 4b is an involute curve, the second discharge port is limited only immediately after the start of discharge. 15a can be opened. Since the gap between the tip of the wrap 4b of the fixed scroll 4 and the outer surface of the wrap 5b of the orbiting scroll 5 is formed larger, the pressure balance between the pair of compression chambers 12a and 12b can be maintained almost simultaneously. The strength of the wraps 4b, 5b does not change.

On the other hand, the reed valve 20 is connected to the discharge port 1
5 and the second discharge port 15a are mounted on a straight line, and the fulcrum 20a is connected to the reed valve 20 on the second discharge port 15a side.
Since it is provided at the end, the reed valve 20 can be shared. Further, when the length of the reed valve 20 from the fulcrum 20a is set to a length corresponding to the operating pressure difference between the discharge port 15 to which the reed valve 20 is attached and the second discharge port 15a, each reed valve 15 Can be operated at substantially the same timing.

FIG. 5 shows a plan view (A) of a fixed scroll of a scroll compressor according to a second embodiment of the present invention, and an exploded perspective view (B) of the fixed scroll and an over-compression preventing device. In this case, the reed valve 20 is mounted substantially at right angles to a straight line connecting the discharge port 15 and the second discharge port 15a, and a fulcrum 20a is provided at an end of the reed valve 20. The reed valves 20 and 21 are provided for each of the discharge port 15 and the second discharge port 15a, and the fulcrum 20a and 21a of the reed valves 20 and 21 are connected to the discharge ports 15 and 21a.
And the length up to the second discharge port 15a are the same. The operation and effect are the same as those of the first embodiment, but the pressure difference between the operations of the respective reed valves 20 and 21 can be further reduced. On the other hand, the reed valve 20,
21 may be the same, but in this case, the operation timings are made substantially the same, and the number of parts can be reduced.

[0026]

According to the present invention, a compression section and an electric motor are arranged in a sealed container, and the compression section is swirled by engaging a fixed scroll having a spiral wrap and the fixed scroll with each other. A revolving scroll having a plurality of pairs of compression chambers having a wound wrap, a shaft for supporting a revolving drive shaft of the revolving scroll, forming a crankshaft at an upper end thereof, and revolving; A scroll compressor comprising a main bearing that supports a crankshaft, a discharge port in the center of the fixed scroll, and a discharge chamber having a normal discharge pressure and the compression chamber in the vicinity of the discharge port. The second discharge port that is in contact with the outer surface of the fixed scroll wrap tip portion opposite to the discharge port, at a position where one of a pair of compression chambers closest to the discharge port communicates with the discharge chamber through the discharge port. Supported and compressed on the other There almost simultaneously the discharge chamber and communicating located, and was set to be provided between the back and the end plate of the fixed scroll. As a result, it is possible to provide a scroll compressor in which the pressure in the pair of compression chambers is balanced without lowering the wrap strength, the flow path resistance is reduced, and overcompression is prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a configuration of a scroll compressor according to a first embodiment of the present invention.

FIGS. 2 (a) to (l) are explanatory diagrams showing a state accompanying a turning motion of the scroll compressor according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a main part in FIG. 2 (e).

FIG. 4 shows a plan view (A) of the fixed scroll of the scroll compressor according to the first embodiment of the present invention, and an exploded perspective view (B) of the fixed scroll and the reed valve.

FIG. 5 shows a plan view (A) of a fixed scroll of a scroll compressor according to a second embodiment of the present invention, and an exploded perspective view (B) of the fixed scroll and a reed valve.

FIG. 6 is a longitudinal sectional view showing a configuration of a conventional scroll compressor.

FIG. 7 shows a plan view (A) of a fixed scroll of a conventional scroll compressor, and an exploded perspective view (B) of the fixed scroll and a reed valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing container 2 Compression part 3 Electric motor 4 Fixed scroll 4a End plate 4b Lap 4b1 Starting point of involute curve 5 Orbiting scroll 5a End plate 5b Lapping 7 Orbital drive shaft 8 Crankshaft 9 Main bearing 10 Metal bearing 11 Shaft 12 Compression chamber 12a, 12b One pair Compression chamber 13 Intake pipe 14 Intake chamber 15 Discharge port 15a Second discharge port 16 Communication path 17 Motor chamber 18 Discharge pipe 19 Discharge chamber 20 Reed valve 20a Support point 21 Reed valve 21a Support point

Claims (9)

[Claims] 1. A compressor and an electric motor are arranged in a sealed container,
A fixed scroll having a spiral wrap; a rotating scroll having a spiral wrap to form a plurality of pairs of compression chambers; A rotating shaft that supports the orbiting drive shaft of the orbiting scroll, forms a crankshaft at the upper end thereof, and revolves; and a main bearing that supports the crankshaft; a discharge port is provided at the center of the fixed scroll; In a scroll compressor provided with the compression chamber and a discharge chamber having a normal discharge pressure near the discharge port, one of a pair of compression chambers closest to the discharge port communicates with the discharge chamber through the discharge port. Corresponding to the position, the other compression chamber communicates with the discharge chamber at substantially the same time, and the fixed scroll moves between the position where the outer surface of the wrap of the fixed scroll is the starting point of the involute curve and the tip of the wrap. A scroll discharge compressor provided with a second discharge port between the end plate and the rear surface of the fixed scroll, the second discharge port being in contact with an outer surface of the fixed scroll wrap distal end opposite to the discharge port. 2. The method according to claim 1, wherein a diameter of the second discharge port is equal to or smaller than a thickness of the fixed scroll at a portion where an outer surface of the wrap is an involute curve. 2. The scroll compressor according to 1. 3. The method according to claim 1, wherein the diameter of the second discharge port is larger than the gap between the wrap end of the fixed scroll and the outer surface of the wrap of the orbiting scroll. Item 3. A scroll compressor according to Item 2. 4. The scroll compressor according to claim 1, wherein a discharge valve for closing both the discharge port and the second discharge port is provided on a back side of the fixed scroll. 5. The scroll compressor according to claim 4, wherein said discharge valve is a reed valve. 6. The reed valve is mounted on a straight line connecting the discharge port and the second discharge port, and a fulcrum is provided at an end of the reed valve on the discharge port side. Item 5
The scroll compressor as described. 7. The reed valve from a fulcrum to a length corresponding to an operating pressure difference between the discharge port to which the reed valve is attached and a second discharge port. 5
Or the scroll compressor according to claim 6. 8. The reed valve according to claim 5, wherein the reed valve is mounted substantially at right angles to a straight line connecting the discharge port and the second discharge port, and a fulcrum is provided at an end of the reed valve. The scroll compressor according to claim 6. 9. The reed valve is provided for each of the discharge port and the second discharge port, and the length from the fulcrum of the reed valve to the discharge port and the second discharge port is the same. 9. The scroll compressor according to claim 8, wherein the scroll compressor has a length.