Patent Application
20080092586
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.
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.
Referring now to drawings, an embodiment of the present invention will be described in detail as follows.
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 4a and 4b formed with nearly 180° phase difference provided. The eccentric parts 4a and 4b have the same diameter and are assembled to be located in the inner diameter portions of the cylinders 8A and 8B. Eccentric rollers 13a and 13b having the same diameter are fitted to the circumferential surfaces of the eccentric parts 4a and 4b.
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 14a and a second cylinder chamber 14b are formed in the cylinders 8A and 8B, respectively. The cylinder chambers 14a and 14b are formed to have the same diameter and height, and the eccentric rollers 13a and 13b are eccentrically rotatably housed therein, respectively.
The size of height of each of the eccentric rollers 13a and 13b is formed to be the same as the size of height of each of the cylinder chambers 14a and 14b. Consequently, the eccentric rollers 13a and 13b have a 180° phase difference with each other, but are set to the identical excluded volume by eccentrically rotating in the cylinder chambers 14a and 14b.
Vane chambers 22a and 22b which communicate with the cylinder chambers 14a and 14b are provided to the cylinders 8A and 8B. In the vane chambers 22a and 22b, vanes 15a and 15b are protrudably and retractably housed with respect to the cylinder chambers 14a and 14b. The vane chambers 22a and 22b include vane housing grooves 23a and 23b in which both sides of the vanes 15a and 15b can slidably move and longitudinal hole portions 24a and 24b provided integrally with the vane housing grooves 23a and 23b and housing rear end portions of the vanes 15a and 15b.
A lateral hole 25 that communicates the outer circumferential surface and the vane chamber 22a 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 15a and the inner circumferential surface of the sealed casing 1, imparts an elastic force (back pressure) to the vane 15a, and brings this head end edge in contact with the eccentric roller 13a.
Although no member other than the vane 15b is housed in the vane chamber 22b on the second cylinder 8B side, the head end edge of the vane 15b is brought in contact with and released from the eccentric roller 13b in accordance with the setting environment for the vane chamber 22b as discussed later and the action of the pressure switching mechanism (means) K later discussed. The head end edge of each of the vanes 15a and 15b 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 13a and 13b, irrespective of the rotating angle of the eccentric roller 13a.
In the event that the eccentric rollers 13a and 13b eccentrically rotate along the inner circumferential wall of the cylinder chambers 14a, 14b, the vanes 15a and 15b make reciprocating motion along the vane housing grooves 23a and 23b, and at the same time, make the vane rear end portion free to advance and retract from the longitudinal hole portions 24a and 24b. 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 22b, and therefore, the vane chamber 22b and the rear end portion of the vane 15b are directly subject to pressure inside the casing. In particular, the second cylinder 8B and the vane chamber 22b 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 15b is slidably housed in the vane chamber 22b and the rear end portion thereof is located in the longitudinal hole portion 24b of the vane chamber 22b, the vane 15b is directly subject to the pressure inside the casing.
Furthermore, the head end portion of the vane 15b faces the second cylinder chamber 14b and the vane head end portion is subject to the pressure inside the cylinder chamber 14b. After all, the vane 15b 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 15b in the direction to separate the vane 15b from the eccentric roller 13b by the force smaller than the differential pressure between the suction pressure guided to the cylinder chamber 14b and the pressure inside the sealed casing 1 guided to the vane chamber 22b, is provided in the vane chamber 22b 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 15b in the direction to separate the vane 15b from the eccentric roller 13b with the force smaller than the differential pressure between the suction pressure exerted to the second cylinder chamber 14b and the pressure inside the sealed casing 1 exerted to the vane chamber 22b.
By providing a permanent magnet as the holding mechanism 10, the holding mechanism magnetically absorbs the vane 15b 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 15b and pulled and energized constantly with predetermined elastic force.
Again as shown in
A first suction pipe 16a and a second suction pipe 16b which communicate with the sealed-type rotary compressor C are connected to the accumulator 17 bottom portion. The first suction pipe 16a passes through the sealed casing 1 and the first cylinder 8A side part and directly communicates with the inside of the first cylinder chamber 14a. The second suction pipe 16b passes through the second cylinder 8B side part via the sealed casing 1 and directly communicates with the inside of the second cylinder chamber 14b.
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 16b that allows the second cylinder chamber 14b 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 16b 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 16b. The second suction pipe 16b 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 16b 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 16a 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 16b. 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 16b and the branch pipe 30 as described later and conversely, block a refrigerant flow from the second suction pipe 16b 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 16b connected to the second cylinder chamber 14b, 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 14b 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 13a and 13b eccentrically rotate in the cylinder chambers 14a and 14b, respectively. Because in the first cylinder 8A, the vane 15a is pressed and energized constantly elastically by the spring member 26, the head end edge of the vane 15a slidably comes in contact with the circumferential wall of the eccentric roller 13a and divides the first cylinder chamber 14a into two, a suction chamber and a compression chamber.
The inner circumferential surface rotary contact position of the cylinder chamber 14a of the eccentric roller 13a aligns with the vane housing groove 23a, and the space capacity of this cylinder chamber 14a is maximized with the vane 15a at the most retracted position. The refrigerant gas is suctioned from the accumulator 17 into the first cylinder chamber 14a via the first suction pipe 16a and the first cylinder chamber 14a is filled with the refrigerant gas. With the eccentric rotation of the eccentric roller 13a, the rotary contact position of the eccentric roller to the inner circumferential surface of the first cylinder chamber 14a moves, and the volume of the partitioned compression chamber of the cylinder chamber 14a decreases. That is, the gas previously guided to the first cylinder chamber 14a is gradually compressed.
When the rotary shaft 4 continues to rotate, the compression chamber volume of the first cylinder chamber 14a 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 14b. Low-pressure evaporated refrigerant gas-liquid separated at the accumulator 17 is guided to the second cylinder chamber 14b via the auxiliary suction pipe 35, the check valve 37, and the second suction pipe 16b.
Consequently, the second cylinder chamber 14b reaches the suction pressure (low-pressure) atmosphere, while the vane chamber 22b is exposed to the inside of the sealed casing 1 and is under the discharge pressure (high pressure). In the above-mentioned vane 15b, 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 15b is pressed and energized against the holding force of the holding mechanism 10 so as to be in sliding contact with the eccentric roller 13b. That is, the compression action takes place in the second cylinder chamber 14b as well, in exactly the same manner as that conducted by the spring member 26 which presses and energizes the vane 15a on the first cylinder chamber 14a side.
After all, in the sealed-type rotary compressor C, compression action is carried out in both the first cylinder chamber 14a and the second cylinder chamber 14b. 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 16b and 16b into relevant cylinder chambers 14a and 14b 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 14a, 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 14b via the opened electromagnetic open-close valve 31 and the second suction pipe 16b. Meanwhile, part of the high-pressure refrigerant tries to flow backward from the second suction tube 16b 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 14b is under the discharge pressure (high-pressure) atmosphere, the vane chamber 22b still remains under the same high-pressure condition as that in the casing. Consequently, the vane 15b equipped to the second cylinder chamber 14b 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 15b maintains the stop condition without moving at the position separated from the roller 13b outer circumferential surface and no compression action takes place in the second cylinder chamber 14b. After all, compression action in the first cylinder chamber 14a only is effective, and operation with the capacity halved is conducted.
Furthermore, since the inside of the second cylinder chamber 14b is under high pressure, no leak of compressed gas from the sealed casing 1 to the second cylinder chamber 14b 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 15b, 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.
First of all, the second suction pipe 16b will be described with reference to
The second suction pipe 16b includes a portion connected too the accumulator 17 via the guide pipe 34 and a portion communicated with the second cylinder chamber 14b 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 14b 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 16b 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 16b 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
Next, the second suction pipe 16b 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 16b 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 16b 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
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 16b 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
As shown in
Then, the check valve 36 is inserted from the top end of the expanded pipe portion 38 of the second suction pipe 16b. 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 16b 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 16b, 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
In this case, since the stepped portion 33d 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 33d, 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 16b 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
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
That is, the first suction pipe 16a 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 16a, 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 16b 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 16b 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 16a, and the top end positions of the two pipes are nearly aligned. In addition, the expanded pipe portion 38 of the second suction pipe 16b 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
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 16b 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 16b, 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 16b 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-000226 | Jan 2005 | JP | national |
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.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP05/23031 | Dec 2005 | US |
| Child | 11772885 | Jul 2007 | US |
