US20080092586A1

US20080092586A1 - Refrigerating cycle device and sealed-type rotary compressor

Info

Publication number: US20080092586A1
Application number: US11/772,885
Authority: US
Inventors: Shoichiro Kitaichi; Toshimasa Aoki; Takeshi Tominaga; Koji Satodate
Original assignee: Toshiba Carrier Corp
Current assignee: Toshiba Carrier Corp
Priority date: 2005-01-04
Filing date: 2007-07-03
Publication date: 2008-04-24
Also published as: CN101094992A; WO2006073048A1; JPWO2006073048A1; JP4700624B2; KR20070086908A

Abstract

There is provided a pressure switching mechanism that switches one compressor mechanism in a sealed-type rotary compressor between regular compression operation and operation stop in accordance with the magnitude of load, and the pressure switching mechanism is equipped with a branch pipe which includes an open/close valve at the middle thereof and which communicates a high-pressure side of a refrigerating cycle to a second suction pipe, an auxiliary suction pipe connected to the suction pipe end part in an accumulator, a check valve which is mounted on either the auxiliary suction pipe or the suction pipe and checks a reverse flow of refrigerant into the accumulator, and a guide pipe which mounts and holds the suction pipe or the auxiliary pipe to the accumulator.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation Application of PCT Application No. PCT/JP2005/023031, filed Dec. 15, 2005, which was published under PCT Article 21(2) in Japanese.
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-000226, filed Jan. 4, 2005, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a refrigerating cycle device equipped with a sealed-type rotary compressor that switches one of multiple compressor mechanisms to operate or stop operating in accordance with the magnitude of load, and the sealed-type rotary compressor.
2. Description of the Related Art
A general sealed-type rotary compressor is configured in an in-casing high-pressure type, in which an electric motor and a rotary-type compressor mechanism that is linked to this electric motor are housed in a sealed casing, and gas compressed at the compressor mechanism is temporarily discharged into the sealed casing.
The compressor mechanism has an eccentric roller housed in a cylinder chamber formed in a cylinder, and the head end edge of a vane constantly comes elastically into contact with the circumferential surface of the eccentric roller. The cylinder chamber is divided into two chambers by the vane, and a suction unit communicates with one chamber, while a discharge unit communicates with the other chamber. A suction pipe is connected to the suction unit and the discharge unit is open to the sealed casing.
In recent years, a two-cylinder-type sealed rotary compressor, with two sets of compressor mechanisms set above and below, has been standardized. In this kind of a compressor, if there can be provided a compressor mechanism which constantly carries out compression operation and a compressor mechanism which can switch between compression operation and operation stop in accordance with the magnitude of load, the specifications are advantageously expanded.
For example, Jpn. Pat. Appln. KOKAI Publication No. 1-247786 (Patent Document 1) discloses a technique related to a compressor having two cylinder chambers and equipped with high-pressure introducing means for forcibly separating and holding a vane of either one of the cylinder chambers from a roller as required and pressurizing the cylinder chamber to interrupt compression action.
In addition, Japanese Patent No. 2803456 (Patent Document 2) discloses a technique related to a compressor having a bypass passage serving as means for introducing high pressure from a sealed container to a suction pipe, in which in one cylinder chamber a vane is brought in contact with a roller by the action of an elastic member even at the time of off-cylinder operation in which no compression action takes place and a compression chamber is constantly partitioned by the vane.

BRIEF SUMMARY OF THE INVENTION

Note that, the compressor according to Patent Document 1 is functionally excellent, but in order to configure high-pressure introducing means, it includes a high-pressure introducing hole which communicates one cylinder chamber with the sealed casing, a two-stage restriction mechanism provided to a refrigerating cycle, and a bypass refrigerant pipe which is branched from the intermediate portion of this restriction mechanism, which communicates with a vane chamber of one side, and which is equipped with an electromagnetic open-close valve in the middle portion thereof.
That is, boring processing to provide the high-pressure introducing means to the compressor is required, and at the same time, the restrictor on the refrigerating cycle must be made into a two-stage restrictor. Furthermore, a bypass refrigerant pipe must be connected between this two-stage restrictor and the cylinder chamber to increase complication of the configuration, which adversely affects the cost.
Furthermore, in the compressor according to Patent Document 2, a bypass pipe connection process to bypass the discharge side and the suction side to the sealed container must be performed, and this adversely affects the cost. Further, because the vane is constantly brought elastically in contact with the roller even during the off-cylinder operation, there occurs a failure that the efficiency is lowered due to the presence of a little compression work or sliding loss.
In both techniques, when the high-pressure introducing means is operated and high pressure is introduced to a predetermined compressor mechanism, there is a fear that the high-pressure refrigerant flows backward from the suction pipe connected to the compressor to an accumulator. However, no specific structure to prevent backflow is described in either Patent Document.
The present invention is made on the basis of the above situation and an object of the present invention is to provide a refrigerating cycle device which has pressure switching means to one compressor mechanism that forms a sealed-type rotary compressor to enable switching between compression operation and operation stop in accordance with the magnitude of load, and which prevents backflow of the refrigerant to the accumulator and prevents detrimental thermal effect in providing the pressure switching means to secure reliability, and the sealed-type rotary compressor.
The present invention has been achieved in order to satisfy the object, and comprises: a sealed-type rotary compressor which houses an electric motor unit and multiple sets of rotary compressor mechanisms connected to the electric motor unit in a sealed casing, which suctions a refrigerant from an accumulator provided outside the sealed casing via suction pipes, respectively, to each of the compressor mechanisms, which compresses the refrigerant at each compressor mechanism, and then, discharges the refrigerant via a space in the sealed casing; a refrigerating cycle circuit composed of this sealed-type rotary compressor and refrigerating cycle components which are linked to communicate via a refrigerant pipe; and pressure switching means switching one of the compressor mechanisms in such a manner that low-pressure gas is guided to the compressor mechanism in the sealed-type rotary compressor to allow it to conduct regular compression operation or high-pressure gas is guided thereto to allow it to stop compression operation in accordance with the magnitude of load, wherein the pressure switching means comprises: a branch pipe, one end of which is connected to a high pressure side of the refrigerating cycle via an electromagnetic open-close valve and the other end of which is connected to a suction pipe which communicates the accumulator to the other compressor mechanism; an auxiliary suction pipe connected to an end part protruding to the inside of the accumulator of the suction pipe; a check valve which is mounted on the auxiliary suction pipe or the suction pipe and which checks reverse flow of refrigerant to the accumulator; and a guide pipe which mounts and holds the suction pipe or the auxiliary suction pipe to the accumulator.
And a sealed-type rotary compressor which houses an electric motor unit and multiple sets of rotary compressor mechanisms to be connected to this electric motor unit in a sealed housing, which suctions a refrigerant from an accumulator provided outside the sealed casing via suction pipes, respectively, to each of the compressor mechanisms, and which compresses the refrigerant in each compressor mechanism, and then, discharges the refrigerant via a space in the sealed casing, the compressor comprising pressure switching means having: a branch pipe, one end of which is connected to a high pressure side of the refrigerating cycle via an electromagnetic open-close valve and the other end of which is connected to a suction pipe which communicates the accumulator to the other compressor mechanism; an auxiliary suction pipe connected to an end part protruding to the inside of the accumulator of the suction pipe; a check valve which is mounted on the auxiliary suction pipe or the suction pipe and which checks reverse flow of refrigerant to the accumulator; and a guide pipe which mounts and holds the suction pipe or the auxiliary suction pipe to the accumulator.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a longitudinal cross-sectional view of a sealed-type rotary compressor and configuration diagram of a refrigerating cycle according to a first embodiment of the present invention.
FIG. 2 is an explodes perspective view of a first cylinder and a second cylinder according to the embodiment.
FIG. 3A is a front view with part of a second suction pipe partially shown in a cross section according to the embodiment.
FIG. 3B is a side view of the second suction pipe.
FIG. 4A is a front view showing the second suction pipe, a disassembled check valve and auxiliary suction pipe partially cut away.
FIG. 4B is a front view showing the reassembled condition of the second suction pipe, the check valve and the auxiliary suction pipe partially cut away.
FIG. 4C is a front view of part of a branch pipe according to the embodiment.
FIG. 5 is a front view of a subassembly according to the embodiment.
FIG. 6A is an exploded view of an accumulator according to the embodiment.
FIG. 6B is an assembled view of the accumulator according to the embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to drawings, an embodiment of the present invention will be described in detail as follows.
FIG. 1 is a cross-sectional view of a sealed-type rotary compressor C which configures a refrigerating cycle device and configuration diagram of a refrigerating cycle circuit R.
First of all, the sealed-type rotary compressor C will be described. The reference number 1 designates a sealed casing. A compressor mechanism 2 is provided at a lower part of this sealed casing 1, and an electric motor unit 3 is provided at the upper part. These electric motor unit 3 and compressor mechanism 2 are linked via a rotary shaft 4.
For example, a brushless DC synchronous motor (or an AC motor or commercial motor) is used for the electric motor unit 3, which is configured with a stator 5 fixed to the inner surface of the sealed casing 1 and a rotor 6 arranged inside this stator 5 with a predetermined clearance and having the rotary shaft 4 inserted thereto. The electric motor unit 3 is electrically connected to an inverter which varies the operating frequency and a control unit which controls the inverter (both not illustrated).
The compressor mechanism 2 is equipped with a first cylinder 8A and a second cylinder 8B arranged vertically via an intermediate partition board 7 at the bottom of the rotary shaft 4. These first and second cylinders 8A and 8B are set in such a manner that they differ from each other in profile and dimensions and have the same inner diameter.
The size of the outer diameter of the first cylinder 8A is formed to be slightly larger than the size of the inner diameter of the sealed casing 1 and press-fitted to the inner circumferential surface of the sealed casing 1, and positioned and fixed by welding from the outside of the sealed casing 1. A main bearing 9 is laid on the top surface part of the first cylinder 8A, and is mounted and fixed to the cylinder 8A via a fixing bolt together with a valve cover “a”. A sub-bearing 11 is laid on the bottom surface part of the second cylinder 8B, and is mounted and fixed to the first cylinder 8A via a fixing bolt together with a valve cover “b”.
The sizes of the outer diameter of the intermediate partition board 7 and the sub-bearing 11 are larger to some extent than the size of the inner diameter of the second cylinder 8B, and the inner diameter position of the cylinder 8B deviates from the cylinder center. Consequently, part of the outer circumference of the second cylinder 8B protrudes in the radial direction from the outer diameter of the intermediate partition board 7 and the sub-bearing 11.
On the other hand, the rotary shaft 4 has its midway part and bottom end part rotatably pivoted between the main bearing 9 and the sub-bearing 11. Furthermore, the rotary shaft 4 passes through the inside of each of the cylinders 8A and 8B and is equipped integrally with two eccentric parts 4 a and 4 b formed with nearly 180° phase difference provided. The eccentric parts 4 a and 4 b have the same diameter and are assembled to be located in the inner diameter portions of the cylinders 8A and 8B. Eccentric rollers 13 a and 13 b having the same diameter are fitted to the circumferential surfaces of the eccentric parts 4 a and 4 b.
The first cylinder 8A and the second cylinder 8B have the top and bottom surfaces partitioned by the intermediate partition board 7, main bearing 9, and sub-bearing 11, and a first cylinder chamber 14 a and a second cylinder chamber 14 b are formed in the cylinders 8A and 8B, respectively. The cylinder chambers 14 a and 14 b are formed to have the same diameter and height, and the eccentric rollers 13 a and 13 b are eccentrically rotatably housed therein, respectively.
The size of height of each of the eccentric rollers 13 a and 13 b is formed to be the same as the size of height of each of the cylinder chambers 14 a and 14 b. Consequently, the eccentric rollers 13 a and 13 b have a 180° phase difference with each other, but are set to the identical excluded volume by eccentrically rotating in the cylinder chambers 14 a and 14 b.
FIG. 2 is a perspective view that shows the first cylinder 8A and the second cylinder 8B in a disassembled condition.
Vane chambers 22 a and 22 b which communicate with the cylinder chambers 14 a and 14 b are provided to the cylinders 8A and 8B. In the vane chambers 22 a and 22 b, vanes 15 a and 15 b are protrudably and retractably housed with respect to the cylinder chambers 14 a and 14 b. The vane chambers 22 a and 22 b include vane housing grooves 23 a and 23 b in which both sides of the vanes 15 a and 15 b can slidably move and longitudinal hole portions 24 a and 24 b provided integrally with the vane housing grooves 23 a and 23 b and housing rear end portions of the vanes 15 a and 15 b.
A lateral hole 25 that communicates the outer circumferential surface and the vane chamber 22 a is provided to the first cylinder 8A, in which a spring member 26 is housed. The spring member 26 is a compression spring which is allowed to intervene between the back-side end face of the vane 15 a and the inner circumferential surface of the sealed casing 1, imparts an elastic force (back pressure) to the vane 15 a, and brings this head end edge in contact with the eccentric roller 13 a.
Although no member other than the vane 15 b is housed in the vane chamber 22 b on the second cylinder 8B side, the head end edge of the vane 15 b is brought in contact with and released from the eccentric roller 13 b in accordance with the setting environment for the vane chamber 22 b as discussed later and the action of the pressure switching mechanism (means) K later discussed. The head end edge of each of the vanes 15 a and 15 b is formed in a semicircle as seen in the planar view, and can make line contact with circular-form circumferential walls, as seen in the planar view, of the eccentric rollers 13 a and 13 b, irrespective of the rotating angle of the eccentric roller 13 a.
In the event that the eccentric rollers 13 a and 13 b eccentrically rotate along the inner circumferential wall of the cylinder chambers 14 a, 14 b, the vanes 15 a and 15 b make reciprocating motion along the vane housing grooves 23 a and 23 b, and at the same time, make the vane rear end portion free to advance and retract from the longitudinal hole portions 24 a and 24 b. As described above, from the relationship between the dimensions and profile of the second cylinder 8B and the outer diameter dimensions of the intermediate partition board 7 and the sub-bearing 11, part of the profile of the second cylinder 8B is exposed to the inside of the sealed casing 1.
The portion exposed to the sealed casing 1 is designed to correspond to the vane chamber 22 b, and therefore, the vane chamber 22 b and the rear end portion of the vane 15 b are directly subject to pressure inside the casing. In particular, the second cylinder 8B and the vane chamber 22 b are of a fixed structure by itself and are not subject to any influence even if pressure inside the casing is exerted, but because the vane 15 b is slidably housed in the vane chamber 22 b and the rear end portion thereof is located in the longitudinal hole portion 24 b of the vane chamber 22 b, the vane 15 b is directly subject to the pressure inside the casing.
Furthermore, the head end portion of the vane 15 b faces the second cylinder chamber 14 b and the vane head end portion is subject to the pressure inside the cylinder chamber 14 b. After all, the vane 15 b is configured to move in the direction from larger pressure to smaller pressure in accordance with the magnitude of pressures to which the head end portion and the rear end portion are subjected.
Fixing holes or screw holes through which the fixing bolts are inserted or threadably inserted are provided to each of the cylinders 8A and 8B, and a circular-arc form gas passage hole 27 is provided to the first cylinder 8A only. In particular, a holding mechanism 10, which energizes the vane 15 b in the direction to separate the vane 15 b from the eccentric roller 13 b by the force smaller than the differential pressure between the suction pressure guided to the cylinder chamber 14 b and the pressure inside the sealed casing 1 guided to the vane chamber 22 b, is provided in the vane chamber 22 b on the second cylinder 8B side.
For the holding mechanism 10, any of permanent magnet, electromagnet, or elastic body may be used. To discuss further, the holding mechanism 10 energizes and holds the vane 15 b in the direction to separate the vane 15 b from the eccentric roller 13 b with the force smaller than the differential pressure between the suction pressure exerted to the second cylinder chamber 14 b and the pressure inside the sealed casing 1 exerted to the vane chamber 22 b.
By providing a permanent magnet as the holding mechanism 10, the holding mechanism magnetically absorbs the vane 15 b constantly by a predetermined force. Alternatively, an electromagnet may be provided in place of the permanent magnet and magnetic absorption may be conducted as required. Alternatively, the holding mechanism 10 is made to be an extension spring, which is an elastic body. One end portion of the extension spring may be allowed to latch on the rear end portion of the vane 15 b and pulled and energized constantly with predetermined elastic force.
Again as shown in FIG. 1, a refrigerant pipe 18 which is a discharge port of compressed gas is connected to the top end of the sealed casing 1 that configures the sealed-type rotary compressor C. An outdoor heat exchanger 20 and an electronic expansion valve 21 which is an expansion mechanism are connected to this refrigerant tube 18 via a four-way switching valve 19 and connected to an accumulator 17 via an indoor heat exchanger 22, thereby configuring the refrigerating cycle circuit R.
A first suction pipe 16 a and a second suction pipe 16 b which communicate with the sealed-type rotary compressor C are connected to the accumulator 17 bottom portion. The first suction pipe 16 a passes through the sealed casing 1 and the first cylinder 8A side part and directly communicates with the inside of the first cylinder chamber 14 a. The second suction pipe 16 b passes through the second cylinder 8B side part via the sealed casing 1 and directly communicates with the inside of the second cylinder chamber 14 b.
In the refrigerating cycle circuit R configured in this way, the pressure switching mechanism (means) K to switch operation of the sealed-type rotary compressor C is provided. Now, the pressure switching mechanism K will be described in detail as follows.
The pressure switching mechanism K is equipped with a branch pipe 30, and an electromagnetic open-close valve 31 is provided to the midway portion thereof. The branch pipe 30 includes a first branch pipe 30A whose one end is connected to the midway part of the refrigerant pipe 18 that allows the compressor C to communicate with the four-way switching valve 19 and the other end connected to the electromagnetic open-close valve 31, and a second branch pipe 30B whose one end is connected to the electromagnetic open-close valve 31 and the other end connected to the midway part of the second suction pipe 16 b that allows the second cylinder chamber 14 b to communicate with the accumulator 17. The midway part of the second branch pipe 30B is provided to and supported by the accumulator 17 via a supporting tool 32.
The electromagnetic open-close valve 31 has its opening and closing controlled in accordance with electrical signals from the control unit. That is, the electromagnetic open-close valve 31 conducts the refrigerant from the refrigerant pipe 18 to the second suction pipe 16 b via the branch pipe 30 or interrupts circulation of the refrigerant.
The other end part of the second branch pipe 30B is connected to an end connector 33 provided in the midway part of the second suction pipe 16 b. The second suction pipe 16 b itself is inserted to the guide pipe 34 mounted on the accumulator 17, and connection processing such as brazing is provided at the bottom end c of the guide pipe 34.
The auxiliary suction pipe 35, the second suction pipe 16 b in the accumulator 17 penetrated portion, and the guide pipe 34 are formed perpendicularly with one another, and the auxiliary suction pipe 35 is placed side by side with the first suction pipe 16 a in the accumulator 17 and are adjusted so that the top end positions (height) thereof are aligned with each other.
A check valve 36 is inserted and mounted in the second suction pipe 16 b. The check valve 36 has functions to allow a refrigerant flow from the auxiliary suction pipe 35 to the end connector 33 portion between the second suction pipe 16 b and the branch pipe 30 as described later and conversely, block a refrigerant flow from the second suction pipe 16 b to the accumulator 17 via the auxiliary suction pipe 35.
In this way, the pressure switching mechanism K is configured by the second suction pipe 16 b connected to the second cylinder chamber 14 b, branch pipe 30, electromagnetic open-close valve 31, guide pipe 34, auxiliary suction pipe 35, and check valve 36. As discussed later, in accordance with the switching action of the pressure switching mechanism K, low-pressure suction pressure or high-pressure discharge pressure is guided to the second cylinder chamber 14 b equipped to the second cylinder 8B.
By the way, the configuration and assembly of the pressure switching mechanism K, assembly of the accumulator 17, and mounting of the pressure switching mechanism K to the accumulator 17 will be described later in further detail.
Next discussion is made on the action of the refrigerating cycle device with the above-mentioned sealed-type rotary compressor C.
(1) In the event that regular operation (full-capacity operation) is selected:
After closing the electromagnetic valve 31 which composes the pressure switching mechanism K, operating signals are sent to the electric motor unit 3 via an inverter, and the rotary shaft 4 is rotary-driven. In the compression mechanism 2, the eccentric rollers 13 a and 13 b eccentrically rotate in the cylinder chambers 14 a and 14 b, respectively. Because in the first cylinder 8A, the vane 15 a is pressed and energized constantly elastically by the spring member 26, the head end edge of the vane 15 a slidably comes in contact with the circumferential wall of the eccentric roller 13 a and divides the first cylinder chamber 14 a into two, a suction chamber and a compression chamber.
The inner circumferential surface rotary contact position of the cylinder chamber 14 a of the eccentric roller 13 a aligns with the vane housing groove 23 a, and the space capacity of this cylinder chamber 14 a is maximized with the vane 15 a at the most retracted position. The refrigerant gas is suctioned from the accumulator 17 into the first cylinder chamber 14 a via the first suction pipe 16 a and the first cylinder chamber 14 a is filled with the refrigerant gas. With the eccentric rotation of the eccentric roller 13 a, the rotary contact position of the eccentric roller to the inner circumferential surface of the first cylinder chamber 14 a moves, and the volume of the partitioned compression chamber of the cylinder chamber 14 a decreases. That is, the gas previously guided to the first cylinder chamber 14 a is gradually compressed.
When the rotary shaft 4 continues to rotate, the compression chamber volume of the first cylinder chamber 14 a is further reduced and the gas is compressed, and the gas pressure is increased to a specified level, a discharge valve not illustrated is opened. The high-pressure gas is discharged into and fills the inside of the sealed casing 1 via the valve cover “a”. The high pressure gas is discharged from the refrigerant pipe 18 at the upper part of the sealed casing and is guided to, for example, the outdoor heat exchanger 20 via the four-way switching valve 19.
On the other hand, because the electromagnetic open-close valve 31 is closed in the pressure switching mechanism K, no discharge pressure (high pressure) is guided to the second cylinder chamber 14 b. Low-pressure evaporated refrigerant gas-liquid separated at the accumulator 17 is guided to the second cylinder chamber 14 b via the auxiliary suction pipe 35, the check valve 37, and the second suction pipe 16 b.
Consequently, the second cylinder chamber 14 b reaches the suction pressure (low-pressure) atmosphere, while the vane chamber 22 b is exposed to the inside of the sealed casing 1 and is under the discharge pressure (high pressure). In the above-mentioned vane 15 b, the head end portion thereof is placed under the low-pressure conditions, the rear end portion under the high-pressure conditions, and the differential pressure exists between the front and rear end portions.
By the influence of this differential pressure, the head end portion of the vane 15 b is pressed and energized against the holding force of the holding mechanism 10 so as to be in sliding contact with the eccentric roller 13 b. That is, the compression action takes place in the second cylinder chamber 14 b as well, in exactly the same manner as that conducted by the spring member 26 which presses and energizes the vane 15 a on the first cylinder chamber 14 a side.
After all, in the sealed-type rotary compressor C, compression action is carried out in both the first cylinder chamber 14 a and the second cylinder chamber 14 b. The high-pressure gas discharged from the sealed casing 1 via the refrigerant pipe 18 is guided to the outdoor heat exchanger 20 to be condensed and liquefied, adiabatically expanded by the electronic expansion valve 21, deprives heat-exchanged air of evaporative latent heat at the indoor heat exchanger 23, and carries out cooling function. The refrigerant after evaporation is guided to the accumulator 17, gas-liquid separated, and again suctioned from the first and second suction pipes 16 b and 16 b into relevant cylinder chambers 14 a and 14 b in the compressor C and circulate in the above-mentioned route.
(2) In the event that special operation (halved-capacity operation) is chosen:
When special operation (operation to halve the capacity) is chosen, the electromagnetic open-close valve 31 of the pressure switching mechanism K is opened. When the electric motor unit 3 is conducted and the rotary shaft 4 is rotary-driven, in the first cylinder chamber 14 a, regular compression action takes place as described above, the sealed casing 1 is filled with discharged high-pressure gas and high pressure is achieved inside the casing.
Part of the high-pressure gas discharged from the refrigerant pipe 18 is diverted to the branch pipe 30 and is directly introduced into the second cylinder chamber 14 b via the opened electromagnetic open-close valve 31 and the second suction pipe 16 b. Meanwhile, part of the high-pressure refrigerant tries to flow backward from the second suction tube 16 b in the accumulator 17 direction, but the reverse flow to the accumulator 17 is prevented by the check valve 36.
While the second cylinder chamber 14 b is under the discharge pressure (high-pressure) atmosphere, the vane chamber 22 b still remains under the same high-pressure condition as that in the casing. Consequently, the vane 15 b equipped to the second cylinder chamber 14 b has both front and back ends subjected to influence of high pressure, and there is no differential pressure between the front and back ends. The vane 15 b maintains the stop condition without moving at the position separated from the roller 13 b outer circumferential surface and no compression action takes place in the second cylinder chamber 14 b. After all, compression action in the first cylinder chamber 14 a only is effective, and operation with the capacity halved is conducted.
Furthermore, since the inside of the second cylinder chamber 14 b is under high pressure, no leak of compressed gas from the sealed casing 1 to the second cylinder chamber 14 b occurs and no loss caused by the leakage occurs, either. Consequently, operation with the capacity halved is enabled without degrading the compression efficiency.
For example, as compared to the case in which the rotating speed is adjusted so that the capacity with the excluded volume of the compressor mechanism 2 is halved, adopting the above-mentioned halved-capacity operation can conduct the halved-capacity operation with the same high rotating speed as that of regular operation maintained and the improved compression efficiency can be obtained.
The minimum capacity by minimum rotating speed established by the lubricity in the compression mechanism 2 can be lowered by varying the excluded volume to half, and the minimum capacity can be expanded to provide a refrigerating cycle device that enables finely-tuned temperature and humidity control. In the compressor R, with a simple construction only by omitting the spring member that energizes the vane 15 b, the volume can be varied, advantageous cost is achieved, superb manufacturing capability is achieved, and high efficiency is achieved.
When the maximum capacity is required, the predetermined capacity is secured by two-cylinder operation, and a wide range of capacity can be secured with one compressor. That is, by controlling the opening and closing of the electromagnetic open-close valve 31 in accordance with the operation mode, the required capacity can be easily obtained.
Next, the configuration and assembly of pressure switching mechanism K, assembly of the accumulator 17, and mounting of the pressure switching mechanism K to the accumulator 17 will be discussed in detail as follows.
FIG. 3 is a partial sectional view and bottom view of the second suction valve 16 b; FIG. 4, a view to explain the configuration and the assembly of the second suction pipe 16 b, auxiliary suction pipe 35, and check valve 36; FIG. 5, an enlarged view of the assembled second suction pipe 16 b, auxiliary suction pipe 35 and check valve 35; and FIG. 6, an assembly illustration of the accumulator 17 and partial sectional view of the assembled accumulator 17.
First of all, the second suction pipe 16 b will be described with reference to FIG. 3.
The second suction pipe 16 b includes a portion connected too the accumulator 17 via the guide pipe 34 and a portion communicated with the second cylinder chamber 14 b that passes through the sealed casing 1 and is formed in the second cylinder 8B. The portion connected to the accumulator 17 is directed perpendicularly and the portion communicated with the second cylinder chamber 14 b is directed horizontally, and the midway part is folded nearly at 90°.
A bent portion 37 is formed at the portion of the second suction pipe 16 b folded at 90°. The bent portion 37 protrudes (distance: H) downwards from the portion extended in the horizontal direction to be formed in an R shape, and the end connector 33 is provided to this bent portion 37. The end-connector 33 is located in a range distributed 45° each up and down with the line L as a center drawn in the horizontal direction from the bend center point O of the bent portion 37.
That is, as the processing sequence, the second suction pipe 16 b is in a straight state in the beginning, and at first, the end connector 33 is formed, for example, by bulging or burring using oil pressure. As shown in FIG. 3B only, a stepped portion 33 d formed at the base end of the end connector 33 is formed by post-processing after providing the end connector 33.
Next, the second suction pipe 16 b is bent and the bent portion 37 is formed. At this time, providing the end connector 33 at the above-mentioned location can prevent effects at the time of processing the bent portion 37 from being exerted to the end connector 33 and no deformation occurs.
In addition, the portion of the second suction pipe 16 b extended in the perpendicular direction is formed into an expanded pipe, and this expanded pipe portion 38 is located at the position separated at least by α (2 mm) from the top end of the end connector 33. The expanded pipe portion 38 can be formed by bulging simultaneously with the end connector 33, and carrying out pipe expanding with the size α separated can prevent effects at the time of pipe expanding from being exerted to the end connector 33 and no deformation occurs.
By forming this kind of second suction pipe 16 b and mounting it to the accumulator 17 together with the bent portion 37, the accumulator 17 fixing position can be lowered by the protruded portion H only. That is, the mounting height of the accumulator 17 integrally assembled with the compressor C can be reduced to achieve compactness.
In particular, as shown in FIG. 4A, the check valve 36 includes a ball-form valve disc 40, a valve holder 41 that houses this valve disc 40, and a valve casing 42 which hold the valve holder 41 and whose bottom end part composes a valve seat portion k. The valve holder 41 is formed by folding a thin sheet material, and at the bottom end thereof, a valve hole not illustrated is provided. The valve disc 40 is housed in the valve holder 41 displaceably only in the vertical direction and opens and closes the valve hole in accordance with its position.
The top end of the valve holder 41 is opened and is equipped with a leaf part f folded inwards. This leaf part f is hooked on a latch portion g mounted on the side of the valve casing 42, and the valve holder 41 is suspended to the valve casing 42. The check valve 36 configured in this way has its dimensions set in such a manner that it can be inserted into the expanded pipe portion 38 formed in the second suction pipe 16 b in a tight state.
A positioning stepped portion h, in which a bottom end m subject to pipe expanding of the auxiliary suction pipe 35 is inserted, is provided to the top end portion of the valve casing 42 and a hole portion i is further provided thereto in a linked manner. Consequently, in the valve casing 42, the hole portion i is penetrated and provided along the center axis that encompasses the top-end positioning stepped portion h to the bottom end face. By the way, in FIG. 4A, the horizontal portion of the second suction pipe 16 b is illustrated in a straight form and the bent portion 37 is omitted.
As shown in FIG. 4B, the preassembled check valve 36 is housed in the expanded pipe portion 38 of the second suction pipe 16 b, and the bottom end m of the auxiliary suction pipe 35 is connected to the top end of the expanded pipe portion 38. Specifically, the valve disc 40 is inserted in the valve holder 41 and the valve holder 41 is latched to the valve casing 42 to assemble the check valve 36, and the pipe-expanded bottom end m of auxiliary suction pipe 35 is inserted to the positioning stepped portion h of the valve casing 42.
Then, the check valve 36 is inserted from the top end of the expanded pipe portion 38 of the second suction pipe 16 b. As described above, since the outer diameter of the check valve 36 and the inner diameter of the expanded pipe portion 38 are set to the tight dimensions, the check valve 36 does not drop straight to the bottom end of the expanded pipe portion 38. When the top end of the check valve 36 and the top end of the second suction pipe 16 b are aligned to each other, insertion of the check valve 36 into the expanded pipe portion 38 is stopped.
Thereafter, high-frequency brazing will be performed to the connection d where the top end of the expanded pipe portion 38, the top end of the check valve 36, and the bottom end m of the auxiliary suction pipe 35 are located at the same position. Consequently, the top end of the second suction pipe 16 b, the top end of the check valve 36, and the bottom end m of the auxiliary suction pipe 35 are integrally linked.
In order to prevent thermal deformation caused by brazing of the valve seat portion k of the valve casing 42 in the check valve 36, it is preferable to perform brazing while cooling by immersing the lower part of the brazed portion (linked portion d) in water, or by other cooling means. For the cooling means, in addition to water immersion, water or inert gas may be allowed to flow to the inside.
As shown in FIG. 4C, a second branch pipe 30B is prepared. Almost all the portion of the second branch pipe 30B is in the vertical state, and it is slanted at the bottom and is bent in the horizontal direction at the bottom end portion. This horizontal end part is inserted into the end connector 33 provided in the second suction pipe 16B and connected by high-frequency brazing.
In this case, since the stepped portion 33 d is formed in the end connector 33, by inserting the end portion of the second branch pipe 30B into the end connector 33 and by striking it against the stepped portion 33 d, the second branch pipe 30B can be positioned and brazed without occurrence of dislocation.
Since the location of the end connector 33 in the second suction pipe 16 b is separated far away from the valve seat portion k of the check valve 36 which has already been assembled in the expanded pipe portion 38, no thermal effect is exerted at the time of brazing the second branch pipe 30B to the end connector 33. Note that, in the event that any thermal effect is suspected, it is desirable to carry out brazing while inert gas such as nitrogen gas is allowed to flow inside.
By the foregoing processing and formation, as shown in FIG. 5, there is obtained a sub-assembly 43 which houses the check valve 36 in the second suction pipe 16 b and connects to integrate the auxiliary suction pipe 35 with the second branch pipe 30B as described above.
On the other hand, the accumulator 17 is configured with a top cup 17A and a bottom cup 17B which are integrally connected after fitting a filter assembly 45 into a nearly intermediate portion in the axial direction as shown in FIGS. 6A and 6B. The refrigerant pipe 18 extended from the compressor C via refrigerating cycle component devices such as the outdoor heat exchanger 20 is connected to the top cup 17A. The first suction pipe 16 a and the guide pipe 34 are mounted on the bottom cup 17B with part of these pipes inserted in the accumulator 17.
That is, the first suction pipe 16 a is formed by being bent nearly in an L form of a vertical portion and a horizontal portion. The straight portion passes through the bottom cup 17B and the top end portion is extended to the filter assembly 45 inside the accumulator 17. The portion protruding downwards from the bottom cup 17B is extended in the horizontal direction towards the compressor C.
The guide pipe 34 is partially inserted into the inside of the accumulator 17 and another part is protruded downwards from the accumulator 17. A top end opening portion n in the accumulator 17 is bent inwards in advance to restrict the opening amount.
The refrigerant pipe 18, the first suction pipe 16 a, and the guide pipe 34 are all brazed to the accumulator 17 along the circumferential surface of the penetrated portion of the accumulator 17, and the sealed condition of the accumulator is not impaired. This completes assembly of the accumulator 17.
The sub-assembly 43 including the second suction pipe 16 b and the like is brought face-to-face to the lower part of the guide pipe 34 in the assembled accumulator 17, and with the top end of the auxiliary suction pipe 35 applied to the bottom end of the guide pipe 34, the auxiliary suction pipe 35 is inserted into the guide pipe 34.
By moving the sub-assembly 43 upwards as it is, the whole auxiliary suction pipe 35 is inserted into the guide pipe 34, and the brazed positions d of the auxiliary suction pipe 35, the check valve 36, and the second suction pipe 16 b are brought in contact with the restricted top-end opening portion n of the guide pipe 34, thereby restricting further elevation.
In the accumulator 17, the auxiliary suction pipe 35 stands upright vertically, and is parallel to the first suction pipe 16 a, and the top end positions of the two pipes are nearly aligned. In addition, the expanded pipe portion 38 of the second suction pipe 16 b is fitted in the guide pipe 34 and the bottom end of the guide pipe 34 and the bottom end position of the expanded pipe portion 38 are nearly aligned.
With the position of the sub-assembly 43 tentatively held, the bottom end of the guide pipe 34 and the bottom end of the expanded pipe portion 38 are brazed along the circumferential surfaces (portion of the reference character c of FIG. 1). The second suction pipe 16 b (sub-assembly 43) is mounted on the accumulator 17 via the guide pipe 34, and assembly of the second suction pipe 16 b equipped with the check valve 36 to the accumulator 17 is completed. It is preferable to separate the brazed position and the valve seat portion k of the check valve 36 by 10 mm or more, and more preferably 20 mm or more. In addition, it is preferable to braze with inert gas such as nitrogen gas allowed to flow inside to prevent oxidation and at the same time to achieve cooling.
Because the check valve 36 is fabricated independently from the accumulator 17, the check valve 36 is not subject to the effect of direct heat when the accumulator 17 is assembled. Furthermore, since the check valve 36 is separated from the brazed position d between the second suction pipe 16 b and the auxiliary suction pipe 35 as well as from the brazed position of the end connector 33 provided to the second branch pipe 30B and the second suction pipe 16 b, the check valve 36 is subject to only a small heat effect, and it is possible to braze while cooling by cooling means. Consequently, high assembly accuracy can be maintained for the check valve 36 and the check valve 36 can be operated in a remarkably smooth manner.
Note that, although the expanded pipe portion 38 is formed in the second suction pipe 16 b to house the check valve 36 in the embodiment, the present invention is not limited to this, and a configuration to house the check valve in the auxiliary suction pipe 35 may be adopted. In addition, one end of the first branch pipe 30A may be connected to the sealed casing.
Furthermore, the present invention is not limited to the above-mentioned embodiment as it is, but in the working stages, the constituent elements may be modified and embodied without departing from the spirit and the scope of the invention. It is possible to form various inventions by suitably combining multiple constituent elements disclosed in the above-mentioned embodiment.
According to the present invention, various advantages are exhibited, such that operation can be switched in accordance with the sizes of load to expand the range of use, the reverse flow of refrigerant to the accumulator can be reliably prevented to improve the refrigerating cycle efficiency, and the detrimental thermal effects can be prevented to thereby maintain the reliability.

Claims

1. A refrigerating cycle device, comprising:

a sealed-type rotary compressor which houses an electric motor unit and multiple sets of rotary compressor mechanisms connected to the electric motor unit in a sealed casing, which suctions a refrigerant from an accumulator provided outside the sealed casing via suction pipes, respectively, to each of the compressor mechanisms, which compresses the refrigerant at each compressor mechanism, and then, discharges the refrigerant via a space in the sealed casing;

a refrigerating cycle circuit composed of this sealed-type rotary compressor and refrigerating cycle components which are linked to communicate via a refrigerant pipe; and

pressure switching means switching one of the compressor mechanisms in such a manner that low-pressure gas is guided to the compressor mechanism in the sealed-type rotary compressor to allow it to conduct regular compression operation or high-pressure gas is guided thereto to allow it to stop compression operation in accordance with the magnitude of load,

wherein the pressure switching means comprises:

a branch pipe, one end of which is connected to a high pressure side of the refrigerating cycle via an electromagnetic open-close valve and the other end of which is connected to a suction pipe which communicates the accumulator to the other compressor mechanism;

an auxiliary suction pipe connected to an end part protruding to the inside of the accumulator of the suction pipe;

a check valve which is mounted on the auxiliary suction pipe or the suction pipe and which checks reverse flow of refrigerant to the accumulator; and

a guide pipe which mounts and holds the suction pipe or the auxiliary suction pipe to the accumulator.

2. The refrigerating cycle device according to claim 1,

wherein the suction pipe includes an end connector unit bulge-forming processed to connect the branch pipe, and an extended tube part to mount the check valve, and the auxiliary suction pipe is integrally linked to the extended tube part.

3. The refrigerating cycle device according to claim 1,

wherein the suction pipe has a bent part protruded downward from a connection portion with the compressor mechanism.

4. The refrigerating cycle device according to claim 2,

5. A sealed-type rotary compressor which houses an electric motor unit and multiple sets of rotary compressor mechanisms to be connected to this electric motor unit in a sealed housing, which suctions a refrigerant from an accumulator provided outside the sealed casing via suction pipes, respectively, to each of the compressor mechanisms, and which compresses the refrigerant in each compressor mechanism, and then, discharges the refrigerant via a space in the sealed casing, the compressor comprising pressure switching means having: