Patent Application
20150056091
The present invention relates to a scroll compressor used for an air conditioner, a cooling device such as a refrigerator, a heat pump type water heater and a hot water heating system.
A conventional compressor used for an air conditioner and a cooling device generally includes a compression mechanism and an electric motor for driving the compression mechanism, and the compression mechanism and the motor are accommodated in a casing. In the compressor, refrigerant gas which returned from the refrigeration cycle is compressed by the compression mechanism, and the refrigerant gas is sent to a refrigeration cycle. When the refrigerant gas is compressed, a gas compression force is applied to the compression mechanism, and this load is supported by a journal bearing. Generally, an axial length of the journal bearing is increased, thereby reducing a surface pressure, and reliability of the journal bearing is secured. Especially in the case of an eccentric bearing, there is tendency that a diameter thereof is smaller than that of a main bearing and a length of the eccentric bearing is relatively increased, thereby reducing a surface pressure of the eccentric bearing (see patent document 1 for example). Here, a diameter of a main bearing member is defined as Dm, a length thereof is defined as Lm, a diameter of an eccentric bearing member is defined as De and a length thereof is defined as Le. Then, a relation Lm/Dm<Le/De is established in patent document 1. This is because the diameter De of the eccentric bearing member becomes small and as a result, Le/De becomes great . That is, a ratio (=Le/De) of the length and the diameter of the eccentric bearing member is made greater than a ratio (=Lm/Dm) of the length and the diameter of the main bearing member. According to this, reliability of both the bearing members and shafts is ensured.
There is also such a configuration that the length Lm of the main bearing member is increased to establish a relation Lm/Dm>Le/De (see patent document 2 for example). The length of the main bearing member is increased, thereby increasing a contact distance between the shaft and the bearing member, and inclination of the shaft is suppressed. That is, reliability of both the bearing members and shafts are ensured like patent document 1.
[Patent Document 1] Japanese Patent No.3731068
[Patent Document 2] Japanese Patent No.3152472
In the conventional configuration shown in patent document 1, however, when the compressor is operated in a state where the shaft inclines, the main bearing member and a main shaft, or the eccentric bearing member and an eccentric shaft come into contact with each other at edge portions of both ends of the bearing member, and they receive gas compression forces at the edge portions. Especially since the gas compression force is applied to the eccentric shaft, a bending amount in the eccentric shaft is increased and the eccentric shaft inclines greater than the main shaft. If a tilting phenomenon of a rotary scroll is generated, contact frequency at the edge portion of the eccentric bearing member becomes higher than contact frequency at the edge portion of the main bearing member. If contact at the edge portion is generated, since a contact area between the bearing member and the shaft is extremely small, a surface pressure becomes extremely high. Therefore, a local wear or abrasion is generated on the bearing member or the shaft. If the operation of the compressor is continued in this sate, the abrasion progresses and there is fear that reliability of the compressor is deteriorated.
According to the conventional configuration of patent document 2, since the main bearing member is long, inclination of the main shaft is suppressed by the main bearing member and inclination of the eccentric shaft is also suppressed. As a result, contact of the eccentric bearing member at the edge portion is resolved. Further, oil film is sufficiently formed between the main bearing member and the main shaft, oil film around the edge portion of the main bearing member receives a gas compression force, and there is a tendency that a surface pressure acting on the main bearing member and the main shaft is reduced. However, if a sliding area between the main bearing member and the main shaft becomes excessively large, since a viscosity loss is increased by oil, there is a problem that compression performance is deteriorated.
The present invention has been accomplished to solve the above-described conventional problems, and it is an object of the invention to provide an efficient scroll compressor realizing high reliability by suppressing local wear of a bearing member or a shaft and suppressing a viscosity loss.
The present invention provides a scroll compressor in which a compression mechanism and a motor are accommodated in a hermetic container, the compression mechanism includes: a fixed scroll having a spiral lap rising from a paneling; a rotary scroll having a spiral lap also rising from a paneling, and meshing with the fixed scroll to form a plurality of compression chambers; a shaft; a main frame supporting the shaft; and a rotation-regulating mechanism for regulating an attitude of the rotary scroll, and in which an eccentric shaft is integrally formed on one end of the shaft, the eccentric shaft is fitted into an eccentric bearing member formed in the rotary scroll, a main shaft of the shaft is fitted into a main bearing member formed in the main frame, refrigerant compressed by the compression mechanism is discharged from a discharge port of the fixed scroll, wherein when a diameter of the main bearing member is defined as Dm and a length thereof is defined as Lm and a diameter of the eccentric bearing member is defined as De and a length thereof is defined as Le, a ratio (=Lm/Dm) of the length and the diameter of the main bearing member and a ratio (=Le/De) of the length and the diameter of the eccentric bearing member satisfy a relation Le/De≦Lm/Dm≦1.
According to this, it is possible to provide a scroll compressor realizing high reliability and high efficiency.
According to the present invention, it is possible to prevent so-called twisting in which when a shaft inclines, and the shaft comes into contact with the edge portions of both ends of the bearing member. That is, since it is possible to prevent a surface pressure from increasing, it is possible to suppress local wear of the bearing member and the shaft.
According to the invention, it is possible to ensure reliability of the bearing member, especially reliability of the eccentric bearing member without increasing a length of the main bearing member. That is, it is possible to reduce a viscosity loss generated if oil exists between the main bearing member and the main shaft, and high reliability can be realized.
A first aspect of the invention provides a scroll compressor in which a compression mechanism and a motor are accommodated in a hermetic container, the compression mechanism comprises: a fixed scroll having a spiral lap rising from a paneling; a rotary scroll having a spiral lap also rising from a paneling, and meshing with the fixed scroll to form a plurality of compression chambers; a shaft; a main frame supporting the shaft; and a rotation-regulating mechanism for regulating an attitude of the rotary scroll, and in which an eccentric shaft is integrally formed on one end of the shaft, the eccentric shaft is fitted into an eccentric bearing member formed in the rotary scroll, a main shaft of the shaft is fitted into a main bearing member formed in the main frame, refrigerant compressed by the compression mechanism is discharged from a discharge port of the fixed scroll, wherein when a diameter of the main bearing member is defined as Dm and a length thereof is defined as Lm and a diameter of an eccentric bearing member is defined as De and a length thereof is defined as Le, a ratio (=Lm/Dm) of the length and the diameter of the main bearing member and a ratio (=Le/De) of the length and the diameter of the eccentric bearing member satisfy a relation Le/De≦Lm/Dm≦1.
According to this configuration, it is possible to prevent so-called twisting in which when a shaft inclines, and the shaft comes into contact with the edge portions of both ends of the bearing member. That is, since it is possible to prevent a surface pressure from increasing, it is possible to suppress local wear of the bearing member and the shaft.
Further, according to this configuration, it is possible to ensure reliability of the bearing member, especially reliability of the eccentric bearing member without increasing a length of the main bearing member. That is, it is possible to reduce a viscosity loss generated if oil exists between the main bearing member and the main shaft, and high reliability can be realized.
According a second aspect of the invention, in the first aspect, a partition plate is provided in the hermetic container, the compression mechanism and the motor are accommodated in a lower low pressure chamber which is partitioned by the partition plate, and refrigerant compressed by the compression mechanism is discharged, through the discharge port of the fixed scroll, into an upper high pressure chamber which is partitioned by the partition plate.
According to this configuration, even when a tilting phenomenon of the rotary scroll is prone to be generated, it is possible to suppress local wear of the eccentric bearing member and the eccentric shaft.
According to a third aspect, in the first or second aspect, the ratio (=Le/De) of the length and the diameter of the eccentric bearing member is 0.5 or higher.
According to this configuration, it is possible to reduce a viscosity loss caused by oil, and to prevent twisting from generating.
According to a fourth aspect of the invention, in any one of the first to third aspects, the shaft includes a rotor, an auxiliary shaft is formed on the shaft located on a side opposite from the main shaft with respect to the rotor, and an auxiliary bearing member which supports the auxiliary shaft is placed in the hermetic container.
According to this configuration, the shaft is supported by two points, i.e., the main shaft and the auxiliary shaft. Therefore, it is possible to suppress the inclination of the shaft and to suppress a bending amount, and generation of twisting can further be prevented.
According to a fifth aspect of the invention, in any one of the first to fourth aspects, a clearance between the main bearing member and the main shaft, a clearance between the eccentric bearing member and the eccentric shaft, and a clearance between the auxiliary bearing member and the auxiliary shaft are 10/10,000 to 40/10,000 times of diameters of the main bearing member, the eccentric bearing member and the auxiliary bearing member, respectively.
According to this configuration, inclinations of the shafts of various portions and a bending amount can be absorbed by clearances of various portions and generation of twisting can be prevented.
According to a sixth aspect of the invention, in any one of the first to fifth aspects, the eccentric shaft includes a movable eccentric member.
According to this configuration, even when the clearances of the various portions are set widely, since the rotary scroll and the fixed scroll reliably have contact points during operation, it is possible to provide a scroll compressor having both high reliability and high efficiency.
An embodiment of the present invention will be described below with reference to the drawings. The invention is not limited to the embodiment.
An interior of the hermetic container 1 is partitioned by a partition plate 6 into an upper high pressure chamber 2 and a lower low pressure chamber 3. The compression mechanism 4, the motor 5 and an oil reservoir 9 in which oil 9a is stored are placed in the low pressure chamber 3.
A suction pipe 7 and a discharge pipe 8 are fixed to the hermetic container 1 by welding. The suction pipe 7 and the discharge pipe 8 are in communication with an exterior of the hermetic container 1, and are connected to members which configure a refrigeration cycle. Refrigerant gas is introduced into the hermetic container 1 from the exterior of the hermetic container 1 through the suction pipe 7, and compressed refrigerant gas is sent to outside of the hermetic container 1 from the high pressure chamber 2 through the discharge pipe 8.
A main frame 12 is fixed in the hermetic container 1 by welding or shrink fitting, and the main frame 12 pivotally supports a shaft 13. A fixed scroll 10 is fixed to the main frame 12 through a bolt. A rotary scroll 11 meshes with the fixed scroll 10, and the rotary scroll 11 is sandwiched between the main frame 12 and the fixed scroll 10. The main frame 12, the fixed scroll 10 and the rotary scroll 11 configure the scroll type compression mechanism 4.
If refrigerant gas is compressed, since pressure of the refrigerant gas is increased, pressure of the refrigerant gas is applied to the rotary scroll 11 in a direction separating away from the fixed scroll 10. Hence, the rotary scroll 11 receives pressure of the refrigerant gas by a thrust bearing 12t formed on the main frame 12. Since the rotary scroll 11 and the fixed scroll 10 are separated from each other by the pressure of the compressed refrigerant gas, chip seals are attached to lap tip ends of the rotary scroll 11 and the fixed scroll 10. According to this, leakage of refrigerant gas from gaps of the lap tip ends is suppressed, and high compression efficiency is realized.
A positional relation between the rotary scroll 11 and the fixed scroll 10 is restricted by a rotation-regulating mechanism 15 such as an Oldham ring. The rotation-regulating mechanism 15 prevents the rotary scroll 11 from rotating, and also guides the rotary scroll 11 so that it moves in a circular orbit manner. The rotary scroll 11 is eccentrically driven by fitting a movable eccentric member 14 over an eccentric shaft 13e provided on an upper end of the shaft 13. By this eccentric driving operation, a compression chamber 17 formed between the fixed scroll 10 and the rotary scroll 11 moves from an outer periphery toward a center of the fixed scroll 10 to reduce a capacity of the compression chamber 17, thereby carrying out a compressing operation.
The motor 5 is composed of a stator 5b fixed to an inner wall surface of the hermetic container 1, and a rotor 5a which is rotatably supported by an inner side of the stator 5b. The shaft 13 is coupled to the rotor 5a in a penetrating state. One of ends of the shaft 13 is a main shaft 13m, and the main shaft 13m is rotatably supported by a main bearing member 12m provided on the main frame 12. The other end of the shaft 13 is an auxiliary shaft 13s, and the auxiliary shaft 13s is rotatably supported by an auxiliary bearing member 16s provided on an auxiliary shaft plate 16.
Next, flow of refrigerant gas will be described. Refrigerant gas sucked from the suction pipe 7 is guided into the hermetic container 1, a portion of the refrigerant gas is supplied directly to the compression mechanism 4, other portion of the refrigerant gas cools the motor 5 and then, this refrigerant gas is supplied to the compression mechanism 4. According to this, the motor 5 is cooled, and control is performed such that winding temperature of the motor 5 does not exceed a predetermined value. Refrigerant gas supplied to the compression mechanism 4 is compressed by capacity variation of the compression chamber 17, and the refrigerant gas moves toward centers of the fixed scroll 10 and the rotary scroll 11. A discharge port 10a is formed in a central portion of the fixed scroll 10. The discharge port 10a is provided with a check valve 18 such as a reed valve and a float valve. If pressure reaches a predetermined value, the refrigerant gas pushes the check valve 18 open, the refrigerant gas flows into the high pressure chamber 2 and is sent from the discharge pipe 8 into the refrigeration cycle.
Next, flow of oil 9a will be described. An oil pickup 19 is attached to a lower end of the shaft 13, and an oil panel 20 is provided in the oil pickup 19. If the shaft 13 rotates, oil 9a in the oil reservoir 9 is sucked up by the oil panel 20 and then, the oil 9a flows upward in an oil passage 13i formed in the shaft 13. The oil passage 13i is formed in a state where it is eccentric with respect to a center of a rotation shaft, and a centrifugal force acts on the oil 9a. According to this, the oil 9a is guided to the main shaft 13m of the shaft 13 and to the end of the shaft 13. The oil 9a which reaches the main shaft 13m passes through a lateral hole 13h formed in the shaft 13, the oil 9a is supplied to a fitting portion between the main bearing member 12m and the main shaft 13m and the oil 9a functions as lubricant oil. Similarly, oil 9a which reaches the end of the shaft 13 is supplied to a fitting portion between an eccentric bearing member 11e and the eccentric shaft 13e, and the oil 9a functions as lubricant oil. The oil 9a which lubricated the fitting portions of the bearings reaches a back space 21 which is surrounded by the main frame 12 and a paneling of the rotary scroll 11. Thereafter, the oil 9a lubricates the thrust bearing 12t, the oil 9a is guided to an inner peripheral surface of the hermetic container 1 through an interior passage 12c of the main frame 12, passes through a notch and the like of the stator 5b and returns to the oil reservoir 9.
Configurations of the bearings according to the embodiment will be described below.
In the case of the journal bearing, generally, surface pressure is reduced by increasing a length thereof in its axial direction to ensure reliability. Especially, a gas compression force acts on the eccentric shaft 13e and bending is generated in the shaft 13 by a load of the gas compression force. Therefore, the shaft 13 comes into contact with edge portions of both ends of the eccentric bearing member 11e, and so-called twisting is prone to occur. If the twisting occurs, since a contact area between the eccentric bearing member lie and the eccentric shaft 13e becomes extremely small, surface pressure becomes extremely large, and local wear is generated in the eccentric bearing member 11e or the eccentric shaft 13e . If the operation of the compressor is continued in this state, there is fear that the wear progresses and reliability is deteriorated. This phenomenon is not limited to the eccentric bearing member 11e and the eccentric shaft 13e, and the same phenomenon may occur in the main bearing member 12m and the main shaft 13m.
More specifically, since the eccentric bearing member 11e is more flat than the main bearing member 12m, tolerance with respect to the inclination of the eccentric bearing member 11e is increased. In other words, even if the eccentric shaft 13e inclines, the eccentric shaft 13e does not come into contact with the edge portions of the both ends of the eccentric bearing member 11e. To prevent contact at the edge portions of the both ends of the main bearing member 12m even if the main shaft 13m inclines, and to reduce, to the utmost, a viscosity loss of the main bearing member 12m caused by oil 9a, it is preferable that the ratio (=Lm/Dm) of the length and the diameter is set to 1 or less. This embodiment is based on the assumption that clearances between the bearing members 12m, 11e, 16s and the shafts 13e, 13m, 13s are set with a constant ratio with respect to the diameters, but under this condition, the more flat the bearing member becomes, the higher the tolerance with respect to inclination becomes. Therefore, contact at the edge portions of the both ends of the eccentric bearing member 11e is avoided. From the above reason, in this embodiment, a scroll compressor having both high reliability and high efficiency can be realized.
As described above, the partition plate 6 is provided in the hermetic container 1, and the partition plate 6 partitions the hermetic container 1 into the upper high pressure chamber 2 and the lower low pressure chamber 3. The compression mechanism 4 and the motor 5 are accommodated in the low pressure chamber 3, refrigerant gas compressed by the compression mechanism 4 is discharged, through the discharge port 10a of the fixed scroll 10, into the high pressure chamber 2 which is partitioned by the partition plate 6. In this case, since the compression mechanism 4 is placed in the low pressure chamber 3, the rotary scroll 11 receives a force basically in a direction separating away from the fixed scroll 10. Hence, when the compressor is actuated or when pressure is transited, balance of forces in the axial direction of the rotary scroll 11 is lost, and a tilting phenomenon is prone to be generated. In this embodiment, the ratio (=Le/De) of the length and the diameter of the eccentric bearing member 11e is smaller than the ratio (=Lm/Dm) of the length and the diameter of the main bearing member 12m. Hence, even if the tilting phenomenon is generated, contact at the edge portions of the both ends of the eccentric bearing member 11e is avoided. That is, in a low pressure type compressor in which the compression mechanism 4 is accommodated in the low pressure chamber 3, the effect of this embodiment is exerted more clearly, and local wear of the eccentric bearing member 11e and the eccentric shaft 13e is suppressed. Hence, it is possible to provide a scroll compressor having high reliability.
If the ratio (=Le/De) of the length and the diameter of the eccentric bearing member 11e is set to 0.5 or higher, it is possible to reduce the viscosity loss caused by the oil 9a and to prevent the twisting. If the ratio (=Le/De) of the length and the diameter of the eccentric bearing member lie becomes lower than 0.5, an oil film is not sufficiently formed between the eccentric bearing member 11e and the eccentric shaft 13e and as a result, the eccentric bearing member lie and the eccentric shaft 13e come into contact with each other. Hence, there is fear that not only performance but also reliability are deteriorated. For this reason, it is preferable that the ratio (=Le/De) of the length and the diameter of the eccentric bearing member lie is set to 0.5 or higher.
The shaft 13 is provided with the rotor 5a, the auxiliary shaft 13s is formed on the opposite side from the main shaft 13m through the rotor 5a, and the auxiliary bearing member 16s which supports the auxiliary shaft 13s is placed in the hermetic container 1. According to this, since the shaft 13 is supported by the two points, i.e., the main shaft 13m and the auxiliary shaft 13s, it is possible to suppress the inclination of the shaft 13 and the bending amount. That is, since the inclination of the main shaft 13m with respect to the main bearing member 12m and the inclination of the eccentric shaft 13e with respect to the eccentric bearing member 11e become small, it is possible to further prevent the twisting from generating.
As shown in
The present invention can be applied to small to large scroll compressors, and can be provided in an air conditioner such as a room air conditioner, a heat pump type water heater, a heat pump type hot water heater and a freezer which are products. According to this, it is possible to realize an energy-saving, environment-friendly and comfortable product.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-284176 | Dec 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/006641 | 11/12/2013 | WO | 00 |
