Patent Application
20210054842
Embodiments described herein relate generally to a multi-cylinder rotary compressor and a refrigeration cycle apparatus comprising the rotary compressor.
Recently, a 3-cylinder rotary compressor is developed, in which three sets of refrigerant compression units are arranged in an axial direction of the rotary shaft to raise compression ability of the refrigerant. The rotary shaft used for a rotary compressor of this type comprises first to third crank portions which eccentrically rotate in a cylinder chamber of the refrigerant compression unit, and a pair of connection shafts provided across between the first crank portion and the second crank portion and between the second crank portion and the third crank portion, respectively.
With the above-described structure, in the 3-cylinder rotary compressor, the full length of the entire rotary shaft is increased and the distance between a pair of bearings which support the rotary shaft is elongated as compared to the case of 2-cylinder rotary compressors in which two sets of refrigerant compression units are arranged in the axial direction of the rotary shaft. Therefore, in order to suppress wobbling of the rotary shaft when rotating at high speed, it is necessary to raise the rigidity of the connection shafts located between the first to third crank portions, respectively.
Under these circumstances, to raise the rigidity of the connecting shaft portion of the rotary shaft, conventionally, there is an attempt in which the cross-sections of the connection shafts are formed into such a shape that a pair of circular arcs are combined together.
On the other hand, it is desirable in 3-cylinder rotary compressors that the eccentric direction of crank portions adjacent to each other should be shifted by 120° in the circumferential direction of the rotary shaft in order to suppress the fluctuation of torque, which may occur when the three sets of refrigerant compression units compress the refrigerant.
However, in a rotary shaft comprising connecting shaft portions whose cross-sections of the connection shafts are formed into such a shape that a pair of circular arcs are combined together, when the eccentric direction of crank portions adjacent to each other is set to be shifted by 120° in the circumferential direction of the rotary shaft, it is unavoidable that of two intersecting points of a pair of circular arcs, a difference occurs between the distance from the center of rotation of the rotary shaft to one intersecting point and the distance from the center of rotation of the rotary shaft to the other intersecting point.
As a result, the position of the center of gravity of the rotary shaft is shifted from the center of rotation of the rotary shaft towards the diametrical direction, and the balance of the rotary shaft deteriorates. The rotary shaft, when unbalanced, causes promotion of vibration of the 3-cylinder rotary compressor.
An object of the embodiments is to obtain a rotary compressor which can achieve less vibration and low noise by maintain the balance of the rotary shaft well while retaining the rigidity of the connecting shaft portion of the rotary shaft.
In general, according to one embodiment, a rotary compressor comprises:
a rotary shaft including a first journal portion supported by a first bearing, a second journal portion provided coaxial with the first journal portion and supported by a second bearing, first to third crank portions provided between the first journal portion and the second journal portion, arranged along an axial direction of the journal portions with intervals respectively therebetween and having circular cross sectional shapes whose eccentric directions are shifted in a circumferential direction of the journal portions, a first connection shaft provided across between the first crank portion and the second crank portion, and a second connection shaft provided across between the second crank portion and the third crank portion, which are integrated as one body, eccentric directions of adjacent pairs of the crank portions being shifted with respect to a rotation center of the journal portions in a circumferential direction within a range of 120°±10°;
ring-like rollers engaged with outer circumferential surfaces of the first to third crank portions, respectively;
a first cylinder body accommodating the respective roller engaged with the first crank portion, and the respective roller defining a first cylinder chamber which eccentrically rotates with the first crank portion;
a second cylinder body accommodating the respective roller engaged with the second crank portion, and the respective roller defining a second cylinder chamber which eccentrically rotates with the second crank portion;
a third cylinder body accommodating the respective roller engaged with the third crank portion, and the respective roller defining a third cylinder chamber which eccentrically rotates with the third crank portion;
a first intermediate partition plate interposed between the first cylinder body and the second cylinder body, in which a first connection shaft of the rotary shaft penetrates; and
a second intermediate partition plate interposed between the second cylinder body and the third cylinder body, in which a second connection shaft of the rotary shaft penetrates.
The first connection shaft of the rotary shaft has a cross sectional shape comprising a first outer surface formed in a position same as an outer circumferential surface of the first crank portion located on an opposite side to the eccentric direction of the first crank portion or a position shifted to a side of the rotation center of the rotary shaft as compared to the outer circumferential surface, at least a middle portion thereof being formed into an arc shape, a second outer surface formed in a position same as an outer circumferential surface of the second crank portion located on an opposite side to the eccentric direction of the second crank portion or a position shifted to a side of the rotation center of the rotary shaft as compared to the outer circumferential surface, at least a middle portion thereof being formed into an arc shape and a third outer surface formed across between the first outer surface and the second outer surface in a position shifted from the rotation center of the rotary shaft.
When, in a cross section normal to the axial direction of the rotary shaft of the first connection shaft, L1 represents a distance from an intersecting point located on one end side where the first outer surface and the second outer surface intersect each other when the first outer surface and the second outer surface are extended, to the rotation center of the rotary shaft, L2 represents a distance from an intersecting point located on an other end side where the first outer surface and the second outer surface intersect each other, to the rotation center of the rotary shaft, and L3 represents a distance from the third outer surface to the rotation center of the rotary shaft,
a relationship of L1>L3≥L2 is satisfied.
Embodiments will be described below with reference to
More specifically, as shown in
When the air conditioner 1 is driven by a cooling mode, the four-way valve 3 switches over so that the first port 3a communicates to the second port 3b and the third port 3c communicates to the fourth port 3d. When the cooling mode operation of the air conditioner 1 is started, a high-temperature and high-pressure vapor-phase refrigerant compressed by the rotary compressor 2 is guided via the four-way valve 3 to the outdoor heat exchanger 4 which functions as a radiator (condenser).
The vapor-phase refrigerant guided to the outdoor heat exchanger 4 is condensed by heat exchange with the air, and it is transformed into a high-pressure liquid-phase refrigerant. The high-pressure liquid-phase refrigerant is depressurized while passing through the expansion device 5 and is transformed into a low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is guided to the indoor heat exchanger 6 which functions as a heat absorber (evaporator) and heat-exchanges with air while passing through the indoor heat exchanger 6.
As a result, the gas-liquid two-phase refrigerant takes heat from the air and evaporates to be transformed into a low-temperature and low-pressure vapor-phase refrigerant. The air passing through the indoor heat exchanger 6 is cooled by latent heat of the vaporization of the liquid-phase refrigerant and is sent as cool wind to a place to be air conditioned (cooled).
The low-temperature and low-pressure vapor-phase refrigerant which has passed the indoor heat exchanger 6 is guided to the accumulator 8 via the four-way valve 3. When a liquid-phase refrigerant portion which has not evaporated is contained in the refrigerant, the liquid-phase refrigerant and the vapor-phase refrigerant are separated from each other by the accumulator 8. The low-temperature and low pressure vapor-phase refrigerant, form which the liquid-phase refrigerant has been separated, is suctioned into the rotary compressor 2, where it is compressed again into a high-temperature and high pressure vapor-phase refrigerant, and then is discharged to the circulation circuit 7.
On the other hand, when the air conditioner 1 is driven by a heating mode, the four-way valve 3 switches over so that the first port 3a communicates to the third port 3c and the second port 3b communicates to the fourth port 3d. Thus, the high-temperature and high-pressure vapor-phase refrigerant discharged from the rotary compressor 2 is guided via the four-way valve 3 to the indoor heat exchanger 6, where the refrigerant heat-exchanges with the air passing through the indoor heat exchanger 6. In other words, the indoor heat exchanger 6 functions as a condenser.
As a result, the vapor-phase refrigerant passing though the indoor heat exchanger 6 is condensed by the heat exchange with the air, and transformed into a high-pressure liquid-phase refrigerant. The air passing through the indoor heat exchanger 6 is heated by the heat exchange with the vapor-phase refrigerant to be warm air and sent to the place to be air-conditioned (heated).
The high temperature liquid-phase refrigerant having passed the indoor heat exchanger 6 is guided to the expansion device 5 and depressurized while passing through the expansion device 5 and is transformed into a low-pressure gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant is guided to the outdoor heat exchanger 4, which functions as an evaporator, and is evaporated here by heat-exchanging with the air to be transformed into a low-temperature and low-pressure vapor-phase refrigerant. The low-temperature and low-pressure vapor-phase refrigerant having passed the outdoor heat exchanger 4 is suctioned into the rotary compressor 2 via the four-way valve 3 and the accumulator 8.
Then, a concrete structure of the rotary compressor 2 used for the air conditioner 1 will be described with reference to
The sealed container 10 includes a cylindrical circumferential wall 10a and is disposed stand up along the vertical direction. A discharge pipe 10b is provided in an upper end portion of the sealed container 10. The discharge pipe 10b is connected to the first port 3a of the four-way valve 3 via the circulation circuit 7. Furthermore, a lubricating oil for lubricating the compression mechanism unit 12 is reserved in a lower portion of the sealed container 10.
The electric motor 11 is accommodated in an axial middle portion of the sealed container 10 so as to be located above a surface level A of the lubricant oil. The electric motor 11 is the so-called inner rotor motor and comprises a stator 13 and a rotor 14. The stator 13 is fixed on an inner surface of the circumferential wall 10a of the sealed container 10. The rotor 14 is located to be coaxial with the sealed container 10 on a central axis O1 thereof and is surrounded by the stator 13.
The compression mechanism unit 12 is accommodated in the lower portion of the sealed container 10 to be immersed in the lubricant oil. As shown in
The first to third refrigerant compression units 15A, 15B and 15C are arranged in a single row along the axial direction of the sealed container 10 with intervals respectively therebetween. The first to third refrigerant compression units 15A, 15B and 15C include a first cylinder body 21a, a second cylinder body 21b and a third cylinder body 21c, respectively. The first to the third cylinder bodies 21a, 21b and 21c are set to have the same thickness along the axial direction of the sealed container 10, for example.
The first intermediate partition plate 16 is interposed between the first cylinder body 21a and the second cylinder body 21b. An upper surface of the first intermediate partition plate 16 is overlaid on a lower surface of the first cylinder body 21a so as to cover an inner diameter portion of the first cylinder body 21a from below. A lower surface of the first intermediate partition plate 16 is overlaid on an upper surface of the second cylinder body 21b so as to cover an inner diameter portion of the second cylinder body 21b from above.
Further, a circular through hole 16a is formed in a central portion of the first intermediate partition plate 16. The through hole 16a is located between the inner diameter portion of the first cylinder body 21a and the inner diameter portion of second cylinder body 21b.
The second intermediate partition plate 17 is interposed between the second cylinder body 21b and the third cylinder body 21c. The upper surface of the second intermediate partition plate 17 is overlaid on a lower surface of second cylinder body 21b so as to cover the inner diameter portion of the second cylinder body 21b from below. The lower surface of the second intermediate partition plate 17 is overlaid on an upper surface of the third cylinder body 21c so as to cover an inner diameter portion of the third cylinder body 21c from above.
Further, a circular through hole 17a is formed in a central portion of the second intermediate partition plate 17. The through hole 17a is located between the inner diameter portion of second cylinder body 21b and the inner diameter portion of third cylinder body 21c.
The first intermediate partition plate 16 and the second intermediate partition plate 17 have the thicknesses T1 and T2, respectively, along the axial direction of the sealed container 10. According to the present embodiment, the thickness T1 of the first intermediate partition plate 16 is greater than the thickness T2 of the second intermediate partition plate 17.
The first bearing 18 is located on the first cylinder body 21a. The first bearing 18 includes a flange portion 23 projecting out towards an inner surface of the circumferential wall 10a of the sealed container 10. The flange portion 23 is stacked on the upper surface of the first cylinder body 21a so as to cover the inner diameter portion of the first cylinder body 21a from above.
According to the present embodiment, the flange portion 23 of the first bearing 18 is surrounded by a ring-shaped support frame 24. The support frame 24 is fixed to a predetermined position of the inner surface of the circumferential wall 10a of the sealed container 10 by, for example, such means as welding or the like.
A lower surface of the support frame 24 is overlaid on an upper surface of an outer circumferential portion of the first cylinder body 21a. The outer circumferential portion of the first cylinder body 21a is jointed to the support frame 24 through a plurality of first fastening bolts 25 (only one is shown).
Further, the flange portion 23 of the first bearing 18, the first cylinder body 21a, the first intermediate partition plate 16 and the second cylinder body 21b are stacked on one another along the axial direction of the sealed container 10 and connected together as an integral body through a plurality of second fastening bolts 26 (only one is shown).
The second bearing 19 is located under the third cylinder body 21c. The second bearing 19 includes a flange portion 27 projecting out towards the inner surface of the circumferential wall 10a of the sealed container 10. The flange portion 27 is stacked on a lower surface of the third cylinder body 21c so as to cover an inner diameter portion of the third cylinder body 21c from below.
The flange portion 27 of the second bearing 19, the third cylinder body 21c, the second intermediate partition plate 17 and the second cylinder body 21b are stacked on one another along the axial direction of the sealed container 10 and connected together as integral body through a plurality of third fastening bolts 28 (only one is shown).
Therefore, the first bearing 18 and the second bearing 19 are spaced apart from each other along the axial direction of the sealed container 10 and also the first to third cylinder bodies 21a, 21b and 21c, the first intermediate partition plate 16 and the second intermediate partition plate 17 are alternately disposed between the first bearing 18 and the second bearing 19.
According to the embodiment, the zone surrounded by the inner diameter portion of first cylinder body 21a, the first intermediate partition plate 16 and the flange portion 23 of the first bearing 18 defines the first cylinder chamber 30.
The zone surrounded by the inner diameter portion of the second cylinder body 21b, the first intermediate partition plate 16 and the second intermediate partition plate 17 defines the second cylinder chamber 31.
Further, the zone surrounded by the inner diameter portion of third cylinder body 21c, the second intermediate partition plate 17 and the flange portion 27 of the second bearing 19 defines the third cylinder chamber 32.
As shown in
In other words, the second intermediate partition plate 17 is thinner than the first intermediate partition plate 16, and thus the second cylinder chamber 31 and the third cylinder chamber 32 are maintained to be close to each other along the axial direction of the sealed container 10.
As shown in
Between the first discharge muffler 33 and the first bearing 18, a first silencer chamber 34 is formed. The first silencer chamber 34 is opened via a plurality of exhaust holes (not shown) made in the first discharge muffler 33 to inside of the sealed container 10.
A second discharge muffler 35 is attached to the second bearing 19. Between the second discharge muffler 35 and the second bearing 19, a second silencer chamber 36 is formed. The second silencer chamber 36 is communicated to the first silencer chamber 34 via a discharge passage (not shown) extending along the axial direction of the sealed container 10.
As shown in
The first journal portion 38 is located in an axial middle portion of the rotary shaft 20 and is rotatably supported by the first bearing 18. The rotor 14 of the electric motor 11 is connected to an upper end portion of the rotary shaft 20 protruding out from the first bearing 18.
The second journal portion 39 is provided to be coaxial with the first journal portion 38 so as to be located in a lower end portion of the rotary shaft 20. The second journal portion 39 is rotatably supported by the second bearing 19.
The first to third crank portions 40a, 40b and 40c are located between the first journal portion 38 and the second journal portion 39 and are arranged along the axial direction of rotary shaft 20 with intervals therebetween. As shown in
The first to third crank portions 40a, 40b and 40c are eccentric to a rotation center line O2 of the rotary shaft 20 which passes the center of rotation of the first journal portion 38 and the second journal portion 39. That is, as shown in
Further, eccentricity amounts e of the first to third crank portions 40a, 40b and 40c with respect to the rotary center line O2 of the rotary shaft 20 are equal to each other.
As shown in
The first connection shaft 41 is located between the first crank portion 40a and the second crank portion 40b and on a rotation center line O2 of the rotary shaft 20 and penetrates the through hole 16a of the first intermediate partition plate 16. The second connection shaft 42 is located between the second crank portion 40b and the third crank portion 40c and on the rotation center line O2 of the rotary shaft 20 and penetrates the through hole 17a of the second intermediate partition plate 17.
A ring-shaped roller 45 is engaged with an outer circumferential surface of the first crank portion 40a. The roller 45 follows the rotary shaft 20 so as to eccentrically rotate in the first cylinder chamber 30 and to bring a part of the outer circumferential surface of the roller 45 into contact slidably with an inner peripheral surface of an inner diameter portion of the first cylinder body 21a.
An upper end surface of the roller 45 is slidably in contact with a lower surface of the flange portion 23 of the first bearing 18. A lower end surface of the roller 45 is slidably in contact with an upper surface of the first intermediate partition plate 16. With this configuration, airtightness of the first cylinder chamber 30 is secured.
A ring-shaped roller 46 is engaged with an outer circumferential surface of the second crank portion 40b. The roller 46 follows the rotary shaft 20 so as to eccentrically rotate in the second cylinder chamber 31 and to bring a part of the outer circumferential surface of roller 46 slidably into contact with an inner peripheral surface of an inner diameter portion of the second cylinder body 21b.
An upper end surface of the roller 46 is slidably in contact with a lower surface of the first intermediate partition plate 16. A lower end surface of the roller 46 is slidably in contact with an upper surface of the second intermediate partition plate 17. With this configuration, airtightness of the second cylinder chamber 31 is secured.
A ring-shaped roller 47 is engaged with an outer circumferential surface of the third crank portion 40c. The roller 47 follows the rotary shaft 20 so as to eccentrically rotate in the third cylinder chamber 32 and to bring a part of the outer circumferential surface of the roller 47 slidably into contact with an inner peripheral surface of an inner diameter portion of the third cylinder body 21c.
An upper end surface of the roller 47 is slidably in contact with a lower surface of the second intermediate partition plate 17. A lower end surface of the roller 47 is slidably in contact with an upper surface of the flange portion 27 of the second bearing 19. With this configuration, airtightness of the third cylinder chamber 32 is secured.
According to this embodiment, the rollers 45, 46 and 47 have inner diameters greater than those of the first connection shaft 41 and the second connection shaft 42 of the rotary shaft 20.
As shown in
A first connection opening 51a is formed inside of the first cylinder body 21a so as to be communicated to the suction area R1 of the first cylinder chamber 30. The first connection opening 51a is opened in a side surface of the first cylinder body 21a. A second connection opening 51b is formed inside of the second cylinder body 21b so as to be communicated to the suction area R1 of the second cylinder chamber 31. The second connection opening 51b is opened in a side surface of the second cylinder body 21b. Ends of the first and second connection openings 51a and 51b are arranged along the axial direction of the sealed container 10 with an interval therebetween.
As shown in
The accumulator 8 comprises a first suction pipe 52a and a second suction pipe 52b which distribute the vapor-phase refrigerant from which the liquid-phase refrigerant has been separated, to the first to third cylinder chamber 30, 31 and 32 of the compression mechanism unit 12. The first and second suction pipes 52a and 52b penetrate the bottom portion of the accumulator 8 and are led outside the accumulator 8.
The first suction pipe 52a is curved into an elbow shape towards a circumferential wall 10a of the sealed container 10 under the accumulator 8. A distal end portion of the first suction pipe 52a penetrates the circumferential wall 10a of the sealed container 10 and is connected to the first connection opening 51a of the first cylinder body 21a.
The second suction pipe 52b is greater in diameter than the first suction pipe 52a and is curved into an elbow shape towards the circumferential wall 10a of the sealed container 10 under the first suction pipe 52a. A distal end portion of the second suction pipe 52b penetrates the circumferential wall 10a of the sealed container 10 and is connected to the second connection opening 51b of the second cylinder body 21b.
The second intermediate partition plate 17 which partitions the second cylinder chamber 31 and the third cylinder chamber 32 from each other comprises a refrigerant distribution opening 53 communicated to the second connection opening 51b of the second cylinder body 21b. The refrigerant distribution opening 53 is communicated to the third cylinder chamber 32 via an introduction path 54 formed in the third cylinder body 21c.
Further, as shown in
A second discharge valve 57, which opens when the pressure of the compression area R2 of the second cylinder chamber 31 reaches a predetermined value, is provided in the first intermediate partition plate 16. A discharge side of the second discharge valve 57 is communicated to the first silencer chamber 34 via a discharge path (not shown) provided inside the first intermediate partition plate 16 and inside the first cylinder body 21a.
A third discharge valve 58, which opens when the pressure of the compression area R2 of the third cylinder chamber 32 reaches a predetermined value, is provided in the flange portion 27 of the second bearing 19. A discharge side of the third discharge valve 58 is communicated to the second silencer chamber 36.
In 3-cylinder rotary compressor 2 with such a structure discussed above, when the rotary shaft 20 is rotated by the electric motor 11, the rollers 45, 46 and 47 follow the first to third crank portions 40a, 40b and 40c and eccentrically rotate in the first to third cylinder chambers 30, 31 and 32, respectively. Thus, volumes of the suction area R1 and the compression area R2 of each of the first to the third cylinder chambers 30, 31 and 32 change, and the vapor-phase refrigerant in the accumulator 8 is suctioned into the suction areas R1 of the first to third cylinder chamber 30, 31 and 32 from the first and second suction pipes 52a and 52b.
The vapor-phase refrigerant suctioned into the suction area R1 of the first cylinder chamber 30 from the first suction pipe 52a is gradually compressed in the process that the suction area R1 transforms to the compression area R2. At the point when the pressure of the vapor-phase refrigerant reaches a predetermined value, the first discharge valve 56 opens to discharge the vapor-phase refrigerant compressed by the first cylinder chamber 30 to the first silencer chamber 34.
A part of the vapor-phase refrigerant guided to the second connection opening 51b of the second cylinder body 21b from the second suction pipe 52b is suctioned into the suction area R1 of the second cylinder chamber 30. The remaining vapor-phase refrigerant guided to the second connection opening 51b is suctioned to the suction area R1 of the third cylinder chamber 31 via the refrigerant distribution opening 53 of the second intermediate partition plate 17 and the introduction path 54 of the third cylinder body 21c.
The vapor-phase refrigerant suction into the suction area R1 of the second cylinder chamber 31 is gradually compressed in the process that the suction area R1 transform to the compression area R2. At the time when the pressure of the vapor-phase refrigerant reaches a predetermined value, the second discharge valve 57 opens to guide the vapor-phase refrigerant compressed by the second cylinder chamber 31 to the first silencer chamber 34 through a discharge path.
The vapor-phase refrigerant suctioned into the suction area R1 of the third cylinder chamber 32 is gradually compressed in the process that the suction area R1 transforms to the compression area R2. At the time when the pressure of the vapor-phase refrigerant reaches a predetermined value, the third discharge valve 58 opens to discharge the vapor-phase refrigerant compressed by the third cylinder chamber 32 to the second silencer chamber 36. The vapor-phase refrigerant discharged to the second silencer chamber 36 is guided to the first silencer chamber 34 through a discharge path.
In this embodiment, the eccentric directions of the first to third crank portions 40a, 40b and 40c are equally shifted in the circumferential direction of the rotary shaft 20. Therefore, there is an equal phase difference in the timing that the vapor-phase refrigerant compressed in each of the first to third cylinder chambers 30, 31 and 32 is discharged.
The vapor-phase refrigerant portions compressed in the first to the third cylinder chambers 30, 31 and 32 join together in the silencer chamber 34 and then it is discharged continually to the inside of the sealed container 10 from an exhaust hole of the first discharge muffler 33. The vapor-phase refrigerant discharged to the inside of sealed container 10 passes the electric motor 11 and then is guided from the discharge pipe 10b to the four-way valve 3.
On the other hand, in the 3-cylinder rotary compressor 2, the rollers 45, 46 and 47 eccentrically rotate in the first to third cylinder chambers 30, 31 and 32 and thus the volumes of the suction area R1 and the compression area R2 of each of the cylinder chambers 30, 31 and 32 change, thereby compressing the vapor-phase refrigerant.
Thus, a load created by the pressure change in the first to third cylinder chamber 30, 31 and 32 is applied to the rotary shaft 20 which eccentrically rotates the rollers 45, 46 and 47, and therefore the torque fluctuation is not avoidable from occurring to the rotary shaft 20. The torque fluctuation may cause vibration and noise of the 3-cylinder rotary compressor 2, and therefore should be suppressed as much as possible.
As shown in
It is generally desired that the torque fluctuation coefficient of the rotary compressor should be 50% or less. Therefore, in this embodiment, the eccentric directions of the first to third crank portions 40a, 40b and 40c are shifted in the circumferential direction of the rotary shaft 20 with respect to the rotation center line O2 of the rotary shaft 20 within a range of 110° to 130° (120°±10°), and particularly, the angle difference θ should be 120°, at which the torque fluctuation coefficient becomes minimum.
According to this embodiment, the second suction pipe 52b communicated to the accumulator 8 is connected to the second cylinder body 21b, and thus the vapor-phase refrigerant compressed by the second cylinder chamber 31 of the second cylinder body 21b is discharged to the discharge path in the first intermediate partition plate 16.
Here, the first intermediate partition plate 16 partitioning the first cylinder chamber 30 and the second cylinder chamber 31 from each other is formed thicker than the second intermediate partition plate 17 partitioning the second cylinder chamber 31 and the third cylinder chamber 32 from each other, and therefore a sufficient volume can be secured for the discharge path in the first intermediate partition plate 16.
At the same time, the second discharge valve 57 is provided for the first intermediate partition plate 16 located on the second cylinder chamber 31, and with this configuration, the length of the path from the second cylinder chamber 31 to the exhaust hole of the first silencer chamber 34 located in an uppermost portion of the compression mechanism unit 12 is short. Therefore, together with the large volume of the discharge path in the first intermediate partition plate 16, a discharge loss of the vapor-phase refrigerant, which may occur until the vapor-phase refrigerant compressed by the second cylinder chamber 31 reaches the first silencer chamber 34, can be suppressed to an extremely low level.
Further, the second intermediate partition plate 17 interposed between the second cylinder chamber 31 and the third cylinder chamber 32 is thinner than the first intermediate partition plate 16, and with this configuration, the distance from the second cylinder body 21b to which the second suction pipe 52b is connected, to the third cylinder chamber 32 can be shortened. Therefore, a suction loss of the vapor-phase refrigerant, which may occur until the vapor-phase refrigerant guided from the second suction pipe 52b to the second connection opening 51b of the second cylinder body 21b reaches the third cylinder chamber 32 through the refrigerant distribution opening 53 of the second intermediate partition plate 17 and the introduction path 54 of the third cylinder body 21c, can be suppressed to an extremely low level.
In addition, the second suction pipe 52b is connected to the second cylinder body 21b located on the third cylinder body 21c. With this configuration, the entire length of the second suction pipe 52b connecting the accumulator 8 and the compression mechanism unit 12 to each other can be shortened. As a result, a suction loss, which may occur while the vapor-phase refrigerant passing through the second suction pipe 32b can be suppressed to an extremely low level.
Thus, despite the structure that the second cylinder chamber 31 and the third cylinder chamber 32 commonly use the only one second suction pipe 52b, the vapor-phase refrigerant returned from the accumulator 8 can be efficiently compressed by the second cylinder chamber 31 and the third cylinder chamber 32, and then discharged to the inside of the sealed container 10.
Next, the dimensions and shapes of the rotary shaft 20 and the roller 46 of the compression mechanism unit 12 will be described.
As shown in
In this embodiment, the first connection shaft 41 provided over between the first crank portion 40a and the second crank portion 40b penetrates the first intermediate partition plate 16, which is thicker than the second intermediate partition plate 17, the length of the shaft thereof is longer than that of the second connection shaft 42.
Thus, the first connection shaft 41 is formed such that the cross sectional shape thereof taken along the direction normal to the rotation center line O2 of the rotary shaft 20 has approximately a leaf shape such as shown in
The first outer surface S1 is located on an opposite side to the eccentric direction of the first crank portion 40a with respect to the rotation center line O2 of the rotary shaft 20 and is slightly shifted to the side of the rotation center line O2 of the rotary shaft 20 as compared to the outer circumferential surface of the first crank portion 40a. Further, the first outer surface S1 is constituted by a cylindrical surface coaxial with the center C1 of the first crank portion 40a and a radius of the first outer surface S1 is greater than a radius of the first journal portion 38 and that of the second journal portion 39.
The second outer surface S2 is located on an opposite side to the eccentric direction of the second crank portion 40b with respect to the rotation center line O2 of the rotary shaft 20 and is slightly shifted to the side of the rotation center line O2 of the rotary shaft 20 as compared to the outer circumferential surface of the second crank portion 40b. Further, the second outer surface S2 is constituted by a cylindrical surface coaxial with the center C2 of the second crank portion 40b and a radius of the second outer surface S2 is greater than a radius of the first journal portion 38 and that of the second journal portion 39.
In this embodiment, one circumferential end of the first outer surface S1 and one circumferential end of the second outer surface S2 are formed to abut to each other, thus defining an edge portion 60 extending in the axial direction of the first connection shaft 41. The edge portion 60 can as well be referred to as an intersecting point between one end of the first outer surface S1 and one end of the second outer surface S2.
The third outer surface S3 is provided across between the first outer surface S1 and the second outer surface S2 on an opposite side to the edge portion 60 while interposing the rotation center line O2 of the rotary shaft 20 therebetween. That is, as shown in
The intersecting point P is located at one end of the approximately leaf shape along a direction of long shaft Z, which defines the cross sectional shape of the first connection shaft 41. Further, the edge portion 60 as the intersecting point is located in the other end the approximately leaf shape along the direction of the long shaft Z, which defines the cross sectional shape of the first connection shaft 41.
When, as shown in
L1>L3≥L2.
In this embodiment, the angle difference θ between the eccentric directions of the first crank portion 40a and the second crank portion 40b is set to 1200, and thus a difference is created between L1 and L2 described above. Therefore, if, for example, the first connection shaft 41 is formed only by the first outer surface S1 and the second outer surface S2, the center of the first connection shaft 41 is eccentric by that difference from the rotation center line O2 of the rotary shaft 20. When the center of the first connection shaft 41 is eccentric, the position of the center of gravity of the connection shaft 41 is shifted off from the rotation center line O2 of the rotary shaft 20, and therefore the rotary shaft 20 is unbalanced.
However, the first connection shaft 41 of this embodiment comprises the third outer surface S3 provided across between the first outer surface S1 and the second outer surface S2 and the third outer surface S3 is located between the intersecting point P and the rotation center line O2. Therefore, the position of the center of gravity of the first connection shaft 41 can be moved to the side of the rotation center line O2 of the rotary shaft 20.
Note that the rigidity of the first connection shaft 41 is increased when setting L3 slightly greater than L2.
Furthermore, with an angle difference θ of 120°, the width dimension Tmax of the first connection shaft 41 crossing normal to the direction of the long shaft Z of the first connection shaft 41 can be increased as compared to the case where the angle difference θ is set to 180°.
As seen in
A distance D4 from the middle point of the rotary shaft 20 along the axial direction of the first crank portion 40a to the axial middle point of the second crank portion 40b is greater than the distance D1 from the axial middle point of the first cylinder chamber 30 to the axial middle point of the second cylinder chamber 31.
Further, as shown in
According to this embodiment, the first outer surface S1 of the first connection shaft 41 is slightly moved over to the side of the rotation center line O2 of the rotary shaft 20 as compared to the outer circumferential surface of the first crank portion 40a. Similarly, the second outer surface S2 of the first connection shaft 41 is slightly moved over to the rotation center line O2 of the rotary shaft 20 as compared to the outer circumferential surface of the second crank portion 40b. With this configuration, the roller 46 to be engaged with the outer circumferential surface of the second crank portion 40b can be guided from a first crank portion 40a side to the second crank portion 40b through the outer side of the first connection shaft 41.
Here, the axial length H1 of the roller 46 is greater than the length H3 of the first connection shaft 41, the lower end surface of the roller 46 abuts against the upper end surface of the second crank portion 40b when the roller 46 having passed the first crank portion 40a reaches the outer side of the first connection shaft 41. Therefore, it is difficult to move the roller 46 from the first connection shaft 41 to the direction of the second crank portion 40b as it is.
To solve this, in this embodiment, chamfers 61a and 61b are provided respectively on both opening edges formed along the axial direction of the inner diameter portion of the roller 46. With the chamfers 61a and 61b, the roller 46 has such a shape that the opening edges thereof are cut over the entire circumferences diagonally along a direction to increase the inner diameter.
Note that in this embodiment, all of the rollers 45, 46 and 47 are common parts, and therefore similar chamfers 61a and 61b are also provided in opening edges of the inner diameter portions of the other rollers 45 and 47.
Next, the operation of attaching the roller 46 to the outer circumferential surface of the second crank portion 40b of the rotary shaft 20 will be described with reference to
Here, the axial length H1 of the roller 46 is greater than the length H3 of the first connection shaft 41, and therefore if the roller 46 is moved to the outer side of the first connection shaft 41, the lower end surface of the roller 46 abuts against the upper end surface of the second crank portion 40b, and further the upper end surface of the roller 46 protrude slightly upward from the lower end surface of the first crank portion 40a.
Under these circumstances, it is difficult to move the roller 46 from the first connection shaft 41 to the direction of the second crank portion 40b. In this embodiment, the chamfers 61a and 61b are formed in the opening edges of the inner diameter portion of the roller 46. With this configuration, at the point when the roller 46 reaches the outer side of the first connection shaft 41, the roller 46 is inclined to the rotary shaft 20 as shown in
Thus, a part of the inner diameter portion of the roller 46, which faces the second outer surface S2 of the first connection shaft 41 is located lower than the first crank portion 40a, and further a gap g is created between the inner circumferential surface of the inner diameter portion of the roller 46 and the second outer surface S2 of the first connection shaft 41. Furthermore, an outer circumferential edge of the first crank portion 40a, which is located on the side of the first connection shaft 41 enters the chamfered portion 61a of the roller 46.
With this configuration, when the roller 46 is moved to the second crank portion 40b from the side of the first connection shaft 41, the state changes to engage the roller 46 with the outer circumferential surface of the second crank portion 40b.
According to the first embodiment, the angle difference θ between the eccentric directions of the first crank portion 40a and the second crank portion 40b is set within a range of 110° to 130° (120°±10°). With this setting, it is possible to secure a sufficient width dimension Tmax of the first connection shaft 41 while suppressing the torque fluctuation of the rotary shaft 20. Thus, the area of the cross section of the first connection shaft 41 along the direction normal to the axial direction of the rotary shaft 20 is increased.
Further, the length H3 of the first connection shaft 41 is less than the axial length H1 of the roller 46. Therefore, together with the increase in the area of the cross section of the first connection shaft 41, the rigidity of the first connection shaft 41 formed across between the first crank portion 40a and the second crank portion 40b can be strengthened.
As a result, wobbling of the shaft of the rotary shaft 20, which may occur during the operation of the 3-cylinder rotary compressor 2 can be suppressed and the vibration and noise of the 3-cylinder rotary compressor 2 can be suppressed to a low level.
Further, the first connection shaft 41 has a cross sectional shape defined by the first outer surface S1, the second outer surface S2 and the third outer surface S3, the position of the center of gravity of the first connection shaft 41 can be moved as much as possible to the side of the rotation center line O2 of the rotary shaft 20.
Therefore, the rotary shaft 20 is well balanced and in this respect as well, wobbling of the shaft of the rotary shaft 20 can be suppressed, thus contributing to the reduction of the vibration of the 3-cylinder rotary compressor 2.
According to this embodiment, the first outer surface S1 of the first connection shaft 41 is constituted by a cylindrical surface coaxial with the center C1 of the first crank portion 40a and the second outer surface S2 is constituted by a cylindrical surface coaxial with the center C2 of the second crank portion 40b. With this structure, the rigidity of the first connection shaft 41 can be raised while enabling the roller 46 to be engaged with the outer circumferential surface of the second crank portion 40b guided to the second crank portion 40b through the outer side of the first connection shaft 41 from the direction of the first crank portion 40a.
In addition, the third outer surface S3 of the first connection shaft 41 is constituted by a cylindrical surface coaxial with the first journal portion 38 of the rotary shaft 20. With this structure, when the first crank portion 40a, the second crank portion 40b and the first journal portion 38 are subjected to a cutting process using, for example, a lathe, the first outer surface S1, the first outer surface S2 and the third outer surface S3 each can be cut by the same process.
Therefore, the workability for the rotary shaft 20 is improved and accordingly, the production cost of the rotary shaft 20 can be reduced.
In this embodiment, in consideration of the workability in the installation of the roller 46, the first outer surface S1 is moved to the side of the rotation center line O2 of the rotary shaft 20 as compared to the outer circumferential surface of the first crank portion 40a, and also the second outer surface S2 is formed in a position close to the rotation center line O2 of the rotary shaft 20 as compared to the outer circumferential surface of the second crank portion 40b in the partial position. However, the embodiments are not limited to this structure.
For example, the first outer surface S1 may be formed on the same surface as that of the outer circumferential portion of the first crank portion 40a, and the second outer surface S2 may be formed on the same surface as that of the outer circumferential surface of the second crank portion 40b.
According to this embodiment, the distance D4 from the middle point of the rotary shaft 20 along the axial direction of the first crank portion 40a to the axial middle point of the second crank portion 40b is greater than the distance D1 from the axial middle point of the first cylinder chamber 30 to the axial middle point of the second cylinder chamber 31.
With this configuration, while moving the roller 46 from the direction of the first crank portion 40a towards the second crank portion 40b through the outer side of the first connection shaft 41, it is difficult for the roller 46 to be caught on the first connection shaft 41. Thus, the roller 46 can be moved easily, and the workability for installing the roller 46 on the rotary shaft 20 can be improved.
Further, in this embodiment, the distance D3 from the middle point of rotary shaft 20 along the axial direction of the second crank portion 40b to the axial middle point of the third crank portion 40c is less than the distance D2 from the axial middle point of the second cylinder chamber 31 to the axial middle point of the third cylinder chamber 32. With this configuration, if the compression of the vapor-phase refrigerant may cause deformation of the rotary shaft 20 from the first bearing 18 and the second bearing 19 as starting points, the bending stress acting on the rotary shaft 20 can be reduced.
As a result, wobbling of the shaft of the rotary shaft 20, regional abrasion of the rollers 46 and 47, and degradation in the sealing performance, which may be caused by being brought into contact with the shaft, can be prevented, thereby making it possible to obtain a high-performance and high-reliability 3-cylinder rotary compressor 2.
In the embodiment, the third outer surface S3 of the first connection shaft 41 is provided on a longitudinal one side of the substantially leaf shape with respect to the rotation center line O2 of the rotary shaft 20. However, the present embodiments are not limited to such a configuration. For example, a pair of third outer surfaces S3 each constituted by a cylindrical surface coaxial with the first journal portion 38 may be provided to respective longitudinal end portions of the first connection shaft 41, and the edge portion 60 may be omitted.
In addition, the first outer surface S1 and the second outer surface S2 of the first connection shaft 41 need not necessarily be curved into an arc shape over the entire circumference. It suffices if at least an intermediate portion of the first outer surface S1 and an intermediate portion of the second outer surface S2, which define Tmax, are curved in an arc shape.
Further, the embodiment is discussed in connection with examples of a general type rotary compressor, in which the vane follows eccentric rotation of the roller and reciprocate to advance to the cylinder chamber and retract to the direction away from the cylinder chamber, but the embodiment are similarly applicable to the so-called swing-type rotary compressor in which, for example, a vane integrally projects outwards from the outer circumferential surface of the roller in the diametrical direction.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
This application is a Continuation Application of PCT Application No. PCT/JP2018/012424, filed Mar. 27, 2018, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2018/012424 | Mar 2018 | US |
| Child | 17033363 | US |
