Hermetic reciprocating compressor with axial motor

Abstract

The reciprocating compressor of the present invention comprises an assembly block (10) and a rotating shaft (20) having at least one inner axial flow passage (21), the inner axial flow passage (21) being connected to at least one inner radial flow passage (22a, 22b) or a cam (23), the cam (23) being connected to a connecting rod (24), the connecting rod (24) being connected to a movable piston (25) in a compression cylinder (26), the reciprocating compressor comprising an oil pump (C), and the reciprocating compressor comprising an axial flow motor having a rotor (30) having a magnet (31) and a stator (40) having a coil (41), the rotor (30) and the stator (40) being fixed to the shaft (20) and the assembly block (10), respectively, by bearings or a fixed structure.

Description

[Technical Field]

[0001] The present invention relates to a hermetic reciprocating compressor, preferably for use in a refrigeration system, having an axial electric motor as a drive source.

[0002] More specifically, the present invention relates to the bearing arrangements and rotor arrangements required for use and driving an axial motor in a hermetic reciprocating compressor in relation to the block and stator. The present invention also relates to a motor support structure for a reciprocating compressor, which supports the axial motor within the hermetic compressor housing. Furthermore, the present invention relates to a mounting structure for an extender element (including a lubricating oil pump) between the lower end of the rotating shaft of the axial motor and the rotor. [Background technology]

[0003] Conventionally, there are a wide range of reciprocating compressor structures widely used in refrigeration fluid compressors. Generally, the main purpose of a reciprocating compressor is to achieve alternate intake and discharge cycles of any working fluid. In the case of a refrigeration fluid compressor, the reciprocating compressor is equipped with a valve that operates in synchronization with the alternate intake and discharge cycles of the reciprocating compressor to allow the discharge fluid to reach a pressure higher than that of the intake fluid.

[0004] The functioning principle of refrigeration compressors based on reciprocating compressors is widely known in the art.

[0005] In principle, the driving force element capable of moving the movable piston consists of a radial flow driven electric motor, the structure of which is shown diagrammatically in prior art FIG.

[0006] In this regard, a radial flow driven electric motor is basically composed of a rotor and a stator, which are configured to exhibit electromagnetic interaction. There are known structures in which the rotor is circularly surrounded by the stator, and structures in which the stator is circularly surrounded by the rotor. In either structure, a rotating magnetic field between the rotor and the stator (see the exemplary arrows in Figure 1) is generated within the physical radial distance (space, clearance) between the rotor and the stator.

[0007] Of course, radially driven electric motors can easily be combined with reciprocating compressors.

[0008] On the other hand, with the recent technological advances in the motor field, axial flow driven motors have been optimized and are now more energy efficient than radial flow driven motors.The basic structure of an axial flow motor is shown in Figure 2, which shows the prior art.

[0009] Generally, an axial flow motor is basically composed of a rotor and a stator configured to exhibit electromagnetic interaction. Known structures include one in which the rotor is disposed above the stator, and another in which the stator is disposed above the rotor. In either structure, a rotating magnetic field (see the exemplary arrows in FIG. 2) between the rotor and the stator is generated within the physical gap (space, clearance) in the axial direction between the rotor and the stator.

[0010] U.S. Patent No. 2,797,857, published July 2, 1957, discloses a motor and compressor unit, and more particularly a hermetic motor-compressor unit for use in refrigeration systems. The motor is of the axial air gap type.

[0011] U.S. Patent Application Publication US2015 / 078532, published on July 4, 2015, discloses an apparatus for generating distributed x-rays, and in particular, an external hot cathode distributed x-ray apparatus in which a plurality of independent hot cathode electron transfer units are arranged via an external approach to generate x-rays and the focal position of an x-ray source device is changed in a predetermined sequence by cathode control or grid control, and a CT apparatus having the external hot cathode distributed x-ray apparatus is also disclosed.

[0012] U.S. Patent No. 4,401,419, published August 30, 1983, discloses a refrigerator motor-compressor having a housing containing a lubricant and a reciprocating compressor driven by a DC electric motor having a disk-shaped rotor and stator. The stator is positioned between the rotor's flux-blocking disks and carries an electronically commutated drive coil. Goniometric indicators detect the rotor's position and apply a signal to an AC generator that modulates a bridge circuit to provide the current flux to drive the rotor.

[0013] The problem with the prior art is that axial flow motors cannot be used in reciprocating compressors because they have a structure that is fundamentally different from that of radial flow motors. As a result, in order to provide an axial flow motor as a driving force element, the reciprocating compressor needs to undergo many technical adaptations (modifications, adjustments, improvements).

[0014] The prior art also has another problem. Unlike radial flow motors, which generate both a rotational force (torque) and a radial magnetic force on the rotor due to electromagnetic interaction between the stator and rotor, axial flow motors are subject to an axial magnetic attraction force between the rotor and stator in addition to the rotor's rotational magnetic force (torque). In other words, the rotating shaft connected to the rotor of an axial flow motor is prone to axial displacement in addition to rotational motion. Therefore, because of this additional vector of displacement force between the rotor and stator, axial flow motors are not applicable to reciprocating compressors. Consequently, the conventional configuration of a reciprocating compressor lacks mechanical elements that form an axial clearance for the shaft and rotor subset in the block and stator subset (a module consisting of the block and stator), nor does it have mechanical elements that can handle (suppress or prevent) axial movement of the rotating shaft during transportation and compressor operating conditions. Summary of the Invention

[0015] An object of the present invention is to provide a reciprocating compressor equipped with an axial flow motor.

[0016] This object is achieved by a reciprocating compressor having the following configuration: crankcase and, a rotating shaft including at least one inner axial channel (path, flow path), the inner axial channel being connected to at least one inner radial channel or cam; the cam is connected to a connecting rod, the connecting rod being connected to a movable piston within a compression cylinder; the reciprocating compressor includes an oil pump; The reciprocating compressor is The motor is an axial flow electric motor consisting of a rotor having a magnet and a stator having a coil. The rotor and the stator are fixed to the shaft and the rotor are fixed to the shaft and the stator are fixed to the shaft and the rotor are fixed to the stator by bearings or fixed members (fixed structures). crankcase is fixed at.

[0017] One of the advantages of the present invention is that it is possible to provide a reciprocating compressor equipped with an axial flow motor.

[0018] Advantageously, in the reciprocating compressor according to the invention, the stator crankcase and the rotor.

[0019] In addition, in the reciprocating compressor according to the present invention, the rotor crankcase and the stator.

[0020] Furthermore, in the reciprocating compressor according to the present invention, the rotor is fixed to the rotary shaft by the first fixing structure.

[0021] In the reciprocating compressor according to the present invention, the stator is fixed by the second fixing structure. crankcase is fixed at.

[0022] The reciprocating compressor according to the present invention has a lower region of the upper flange of the rotating shaft and crankcase and an axial bearing disposed between the upper region of the bearing.

[0023] The reciprocating compressor according to the present invention further comprises an axial bearing disposed between the rotor and the stator.

[0024] Furthermore, in the reciprocating compressor according to the present invention, the stator further includes a radial bearing arranged around the rotating shaft, and this radial bearing has an annular structure that protrudes from the stator and is arranged around a segment (part) of the rotating shaft.

[0025] The reciprocating compressor according to the present invention comprises: Extended bearing hub Further provided are:

[0026] Furthermore, the reciprocating compressor according to the present invention includes a rotor and Extended bearing hub and an axial bearing disposed between them.

[0027] The present invention also provides a reciprocating compressor having the following configuration: crankcase Top and crankcase Consists of the lower part crankcase Equipped with The aforementioned crankcase further has a first through hole and a second through hole, The reciprocating compressor is a rotating shaft having a first portion of the rotating shaft positioned in the first through hole and a second portion of the rotating shaft positioned in the second through hole, the rotating shaft includes an eccentric pin disposed between the first portion and the second portion; the eccentric pin connects to a connecting rod, the connecting rod connects to a movable piston within a compression cylinder; The reciprocating compressor includes an oil pump, The oil pump includes an axial flow motor having a rotor with magnets and a stator with electric coils, The rotor and the stator each have a rotating shaft and crankcase It is fixed to the bearing or fixed member (fixed structure).

[0028] Advantageously, in the reciprocating compressor according to the present invention, the rotor is fixed to the rotary shaft by the first fixing structure.

[0029] In the reciprocating compressor according to the present invention, the stator is fixed by the second fixing structure. crankcase is fixed at

[0030] The reciprocating compressor according to the present invention further includes a first hydrodynamic radial bearing formed in a space between the inner circumferential surface of the first through hole and the first portion of the rotary shaft.

[0031] Furthermore, the reciprocating compressor according to the present invention further includes a second fluid dynamic pressure radial bearing formed in the space between the inner circumferential surface of the second through hole and the second portion of the rotary shaft.

[0032] In the reciprocating compressor according to the present invention, the stator further includes an axial bearing arranged around the rotating shaft, and the axial bearing is defined by an annular structure protruding from the stator and arranged around a rotating shaft segment (a part of the rotating shaft).

[0033] The reciprocating compressor according to the present invention has an eccentric pin and crankcase The bearing further includes an axial bearing disposed between the bearing and the upper portion.

[0034] Furthermore, the reciprocating compressor according to the present invention further comprises an axial bearing disposed between the bearing hub and the rotor.

[0035] Furthermore, in the reciprocating compressor according to the present invention, the rotor is located above the stator, and the rotor has a "Z"-shaped support structure for fixing it to the rotating shaft.

[0036] In addition, in the reciprocating compressor according to the present invention, the rotor and the stator are separated (separated) by a first axial clearance, and the rotor and crankcase are separated by a second axial clearance.

[0037] Furthermore, in the reciprocating compressor according to the present invention, a stator and crankcaseThe first clearance can be adjusted using a bushing disposed between the rotor and the rotating shaft or between the rotor and the rotating shaft.

[0038] Furthermore, in the reciprocating compressor according to the present invention, the second clearance is preferably adjustable by a bushing disposed between the rotor and the rotary shaft.

[0039] In the reciprocating compressor according to the present invention, the first clearance is formed by displacement of the rotor or the stator, and the second clearance is formed by displacement of the bushing or the fixed structure (fixed member).

[0040] Furthermore, the reciprocating compressor according to the present invention further comprises an oil pump provided in a flow path on the axial inside of the rotary shaft, or further comprises an oil pump provided in the rotor.

[0041] The reciprocating compressor according to the present invention further comprises fastening means for physically connecting the oil pump, the rotor, and the rotary shaft.

[0042] A further advantage of the method according to the invention is that it provides a simple and practical reciprocating compressor with significantly reduced dimensions in relation to radial engine reciprocating compressors, with independent adjustment of its axial clearance, which allows for easy industrial production and has a robust design for transportation and operation. [Brief explanation of the drawings]

[0043] The objects and advantages of the present invention will become apparent through the accompanying drawings and the following detailed description of the embodiments, which are given in a non-limiting sense.

[0044] FIG. 1 is a simplified diagram showing a prior art radial flow motor (axial flow motor).

[0045] FIG. 2 is a simplified diagram showing a conventional axial flow motor.

[0046] FIG. 3 is an internal side view of a first embodiment of a reciprocating compressor with an axial flow motor according to the present invention.

[0047] FIG. 4 is another internal side view of the first embodiment of the reciprocating compressor with an axial flow motor according to the present invention.

[0048] FIG. 5 is another internal side view of the first embodiment of the reciprocating compressor with an axial flow motor according to the present invention.

[0049] FIG. 6 is an internal side view of a second embodiment of a reciprocating compressor with an axial flow motor according to the present invention.

[0050] FIG. 7 is a diagram showing another possible configuration of the second embodiment of the reciprocating compressor with an axial flow motor according to the present invention.

[0051] FIG. 8 is a diagram showing possible modifications of the reciprocating compressor with an axial flow motor according to the present invention.

[0052] FIG. 9 is a diagram showing another modified example of the reciprocating compressor with an axial flow motor according to the present invention.

[0053] FIG. 10 is a diagram showing a further modified example of a reciprocating compressor with an axial flow motor according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0054] First embodiment FIG. 3 shows a first embodiment of a reciprocating compressor with an axial flow motor according to the present invention.

[0055] According to Figure 3, the reciprocating compressor is crankcase The motor includes a rotor 10, a rotary shaft 20, an oil pump C, and an axial flow electric motor having a rotor 30 and a stator 40 as main components.

[0056] crankcase 10 has at least one first vertical protrusion 11a and at least one second vertical protrusion 11b for fixing the stator 40. Furthermore, crankcase The rotating shaft 20 is inserted into the through hole 10 .

[0057] The rotating shaft 20 has at least one inner axial channel (inner axial flow path, axial internal flow path) 21 for circulating lubricating oil, and the inner axial flow path 21 extends from the lower end to the upper end of the rotating shaft 20. Furthermore, the inner axial flow path 21 is connected to at least one inner radial flow path 22a, 22b for discharging lubricating oil, and the inner axial flow path 21 and the at least one inner radial flow path 22a, 22b are fluidly connected (communicate) with each other so that the lubricating oil flowing into the inner axial flow path 21 exits (is discharged) through the inner radial flow path 22a, 22b. Furthermore, a cam (crank pin) 23 connected to a connecting rod 24 is provided at the upper end of the rotating shaft 20, and the connecting rod 24 is also connected to a movable piston 25 in a compression cylinder 26.

[0058] The rotor 30 has a magnet 31 and is fixed to the rotating shaft 20 by a first fixing structure (fixing member) 32. The first fixing structure 32 can be any known fixing structure (a fixing structure using interference, welding, adhesive, screws, etc.). The first fixing structure 32 has the function of transmitting the movement of the rotor 30 to the rotating shaft 20.

[0059] The stator 40 has an electric coil 41 and is fixed by a second fixed structure 42. crankcase The second fixing structure 42 is made of any known fixing structure (fixing structure using interference, welding, adhesive, screws, etc.). The second fixing structure 42 is crankcase 10, the stator 40 has the function of keeping the position of the stator 40 stationary (not moving).

[0060] 3, the rotor 30 is disposed above the stator 40. In this state, an axial bearing 50a is provided to limit the relative axial displacement between the rotor 30 and the stator 40. The axial bearing 50a is disposed between the lower region of the upper flange of the rotating shaft 20 and the crankcase The axial bearing 50a (which may be configured as, for example, a plain bearing, a bearing made of a material with a low friction coefficient, or a bushing) not only assists the rotation of the rotating shaft 20, but also prevents the rotating shaft 20 from being displaced in the axial direction due to the magnetic attractive force that exists between the rotor 30 and the stator 40 when the motor is started.

[0061] 4, the stator 40 is positioned above the rotor 30. In this state, an axial bearing 50b is provided to limit the relative axial displacement between the rotor 30 and the stator 40. The axial bearing 50b is disposed between the rotor 30 and the stator 40 or between the rotor 30 and the annular structure 60.

[0062] Furthermore, the first embodiment of the present invention also includes a radial bearing that is integrated with the stator 40 and disposed around the rotating shaft 20. The radial bearing can be any type of bearing known in the art, such as a hydrodynamic bearing (in this case, a bearing in which a predetermined type of lubricant is supplied to a minimum clearance between axially aligned parallel surfaces), a hydrostatic bearing (in this case, a bearing in which a predetermined type of lubricant is force-fed under pressure between two axially aligned parallel surfaces), or a bushing made of a predetermined low-friction or self-lubricating material.

[0063] According to the present invention, the structure of the stator 40 can be used to form a radial bearing for the rotating shaft 20, so that the problems of eccentricity and misalignment of the rotating shaft 20 do not occur.

[0064] 3 and 4, the radial bearing is defined by an annular structure 60 that is integral with the stator 40 and disposed around the rotating shaft 20. More specifically, the annular structure 60 is disposed around a segment of the rotating shaft 20 in which the inner radial channel 22a is disposed.

[0065] Thus, the space formed between the annular structure 60 and the rotating shaft 20 segment is configured to retain a film of lubricating oil (from the inner radial passage 22a) to form a radial fluid dynamic bearing.

[0066] In this way, by using the structure of the stator 40 itself to form a fluid dynamic pressure radial bearing for the rotating shaft 20, a simpler and more compact structure can be achieved. crankcase It is possible to build 10.

[0067] As an option (alternative configuration), according to Figure 5, crankcase 10 is Extended bearing hub In this configuration, the stator 40 is disposed above the rotor 30. Furthermore, the rotor 30 and Extended bearing hub An axial bearing 50c is provided between the bearing 11c and the bearing 50.

[0068] Second embodiment FIG. 6 is a diagram showing a second embodiment of a reciprocating compressor with an axial flow motor according to the present invention.

[0069] According to Figure 6, the reciprocating compressor is crankcase Upper portion 100a and crankcase Has a lower portion 100b crankcase 100, a rotating shaft 200 having a rotating shaft first portion 200a and a rotating shaft second portion 200b, an oil pump C, and an axial flow motor mainly composed of a rotor 300 and a stator 400.

[0070] crankcase The shaft 100 has a first through-hole 120a and a second through-hole 120b for receiving the first portion 200a and the second portion 200b of the rotating shaft, respectively.

[0071] The rotating shaft 200 has an eccentric pin (crank pin) 230 disposed between the first portion 200a and the second portion 200b, and the eccentric pin 230 is connected to a connecting rod 240, which is connected to a movable piston 250 inside a compression cylinder 260.

[0072] The rotor 300 has a magnet 310 and is fixed to the rotating shaft 200 by a first fixing structure 320. The first fixing structure 320 can be any known fixing structure (welding, adhesive, screws, etc.). The first fixing structure 320 has the function of transmitting the movement of the rotor 300 to the rotating shaft 200.

[0073] The stator 400 has an electric coil 410 and is supported by a second fixed structure 420. crankcase 100, and the second fixing structure 420 is made of any known fixing structure (welding, adhesive, screws, etc.). crankcase It has the function of keeping the position of the stator 400 stationary (unmoving) relative to the rotor 100.

[0074] 6, the space between the inner circumferential surface of the first through hole 120a and the first rotating shaft portion 200a receives a film of lubricating oil, forming a first hydrodynamic pressure radial bearing 500a. Similarly, the space between the inner circumferential surface of the second through hole 120b and the second rotating shaft portion 200b also receives a film of lubricating oil, forming a second hydrodynamic pressure radial bearing 500b. These bearings can prevent early wear of the rotating shaft 200, the first through hole 120a, and the second through hole 120b.

[0075] 6, in the second embodiment of the present invention, an axial bearing 600 is provided to stabilize the axial distance between the rotor 300 and the stator 400. Therefore, the axial bearing 600 is crankcase It can be attached between the upper portion 100a.

[0076] Optionally, an axial bearing 600 may be mounted between the bearing hub 700 and the rotor 300 .

[0077] Furthermore, in the second embodiment of the present invention, a radial bearing is provided that is integrated with the stator 400 and arranged around the rotating shaft 200. The radial bearing can consist of any type of bearing known in the art, for example a hydrodynamic bearing (in this case a bearing with some supply of lubricant in a minimal gap between axially aligned parallel surfaces) or a hydrostatic bearing (in this case a bearing with some forced supply of lubricant injected under pressure between two axially aligned parallel surfaces), or it can consist of a bushing made of some low-friction or self-lubricating material.

[0078] According to the present invention, the structure of the stator 400 can be used to form a radial bearing for the rotating shaft 200, so that the problem of the rotating shaft 200 becoming eccentric or misaligned can be prevented.

[0079] 6 and 7, the radial bearing is defined by an annular structure 610 that is integrated with the stator 400 and arranged around the rotating shaft 200. More specifically, the annular structure 610 is arranged around a portion of the rotating shaft 200 (the portion (segment) where the inner radial flow passage 222a is arranged).

[0080] Therefore, the space formed between the annular structure 610 and the above-mentioned portion (segment) of the rotating shaft 200 can retain a film of lubricating oil (from the inner radial flow path 222a), forming a radial fluid dynamic bearing.

[0081] 7 is a diagram showing the configuration of a modified example of the second embodiment, in which the motor is located above the cylinder.

[0082] Configuration applicable to the first and second embodiments The present invention also provides a configuration applicable to the first and second embodiments.

[0083] Referring to FIG. 8, in a configuration in which the rotor 30,300 is above the stator 40,400, the rotor 30,300 has a "Z"-shaped (Z-shaped) support structure A for fixing to the rotating shaft 20,200.

[0084] According to FIG. 9, the rotors 30, 300 and the stators 40, 400 are 1 Axial clearance (spacing) F 1 The rotation axis 20,200 and crankcase 10,100 is the 2 Axial clearance F 2 The first clearance F1 and the second clearance F2 can be adjusted by using a bush B disposed between the rotor 30, 300 and the rotary shaft 20, 200. 1 Clearance F 1 is caused by the rotor 30, 300 being displaced on the bush B or by the stator 40, 400 crankcase Formed by displacement on 10,100, 2 Clearance F 2 is formed by displacing the bushing B on the axis of rotation 20,200.

[0085] The bush B is an annular (sliding) part disposed between the rotor 30, 300 and the shaft 20, 200. 1 Clearance F 1 Regardless of the formation of 2 Clearance F 2 It is possible to form

[0086] No. 2 Clearance F 2 specifies the displacement range of the shaft (for example, 0.1 to 0.5 mm). The clearance F1 is (F 2 = 0) This is to prevent the axis from becoming stuck or from experiencing a very large displacement, which can cause problems during transportation. No. 2 Clearance F 2 When formed, the clearance F2 without changing No. 1 Clearance F 1 (between the rotor and stator) can be adjusted.

[0087] According to Figure 10, the cone-shaped oil pump C The oil pump can be provided in the inner axial passage 21 of the rotating shaft 20, 200 or in the rotor 30, 300. Thus, the amount of oil intake is optimized. C The oil pump also functions as an interface for physical contact between the rotor 30, 300 and the rotating shaft 20, 200, ensuring the fixation of these elements and transmitting the movement of the rotor 30, 300 to the rotating shaft 20, 200. C can be mounted under interference with the rotating shaft 20,200.

[0088] In addition to the embodiments described above, the concepts and ideas of the present invention may be applied to other devices or applications that use the present invention, such as in air compressors.

[0089] Although the present invention has been described in connection with certain preferred embodiments, it is not intended that the invention be limited to the specific embodiments described above. It is intended that the present invention cover all possible alternatives, modifications, and equivalents that are within the spirit and scope of the invention, as defined by the claims.

Claims

1. A reciprocating compressor, Crankcase (10) and a rotating shaft (20) having at least one internal axial flow passage (21); the inner axial flow passage (21) is connected to at least one inner radial flow passage (22a, 22b) or a crank pin (23); The crank pin (23) is connected to a connecting rod (24), and the connecting rod (24) is connected to a movable piston (25) in a compression cylinder (26); The reciprocating compressor further comprises an oil pump (C); The reciprocating compressor is The motor further includes an axial flow motor having a rotor (30) having a magnet (31) and a stator (40) having a coil (41), the rotor (30) is fixed to the rotating shaft (20) by a bush (B), the stator (40) is fixed to the crankcase (10) by a fixing structure (42), and the bush (B) is located inside the rotor (30) when viewed in the radial direction of the rotating shaft (20); the rotor (30) is located between the crankcase (10) and the stator (40), and the rotor (30) and the stator (40) are separated by a first axial clearance (F1); the bush (B), which is disposed between the rotor (30) and the rotating shaft (20), and the crankcase (10) are separated by a second axial clearance (F2a), and the second axial clearance (F2a) is formed at a position higher than the first axial clearance (F1); A reciprocating compressor, characterized in that the first axial clearance (F1) and the second axial clearance (F2a) are adjustable using the bush (B).

2. A reciprocating compressor, Crankcase (10) and a rotating shaft (20) having at least one internal axial flow passage (21); the inner axial flow passage (21) is connected to at least one inner radial flow passage (22a, 22b) or a crank pin (23); The crank pin (23) is connected to a connecting rod (24), and the connecting rod (24) is connected to a movable piston (25) in a compression cylinder (26); The reciprocating compressor further comprises an oil pump (C); The reciprocating compressor is The motor further includes an axial flow motor having a rotor (30) having a magnet (31) and a stator (40) having a coil (41), the rotor (30) is fixed to the rotating shaft (20) by a bush (B), the stator (40) is fixed to the crankcase (10) by a fixing structure (42), and the bush (B) is located inside the rotor (30) when viewed in the radial direction of the rotating shaft (20); the stator (40) is located between the crankcase (10) and the rotor (30), and the rotor (30) and the stator (40) are separated by a first axial clearance (F1); the rotating shaft (20) and the crankcase (10) are separated by a second axial clearance (F2b), and the second axial clearance (F2a) is formed at a position higher than the first axial clearance (F1); The reciprocating compressor, characterized in that the first axial clearance (F1) and the second axial clearance (F2b) are adjustable using the bush (B) disposed between the rotor (30) and the rotating shaft (20).

3. 3. The reciprocating compressor according to claim 1, wherein the stator (40) is fixed to the crankcase (10) by the fixing structure (42).

4. 2. The reciprocating compressor according to claim 1, further comprising an axial bearing (50a) disposed between a lower region of the upper flange of the rotating shaft (20) and an upper region of the crankcase (10).

5. The reciprocating compressor according to claim 2, further comprising an axial bearing (50b) disposed between the bushing (B) of the rotor (30) and the stator (40).

6. 3. The reciprocating compressor according to claim 1, wherein the stator (40) further comprises a radial bearing arranged around the rotating shaft (20), the radial bearing being defined by an annular structure (60) protruding from the stator (40) and arranged around a portion of the rotating shaft (20).

7. 3. The reciprocating compressor according to claim 2, wherein the crankcase (10) further comprises an extended bearing hub (11c), the extended bearing hub (11c) extending in the axial direction of the rotating shaft (20), and the rotating shaft (20) extending through the extended bearing hub (11c).

8. 8. The reciprocating compressor according to claim 7, further comprising an axial bearing (50c) disposed between the bushing (B) of the rotor (30) and the extended bearing hub (11c).

9. A reciprocating compressor, a crankcase (100) consisting of an upper crankcase (100a) and a lower crankcase (100b); the crankcase (100) further has a first through hole (120a) and a second through hole (120b); The reciprocating compressor is a rotating shaft (200) having a rotating shaft first portion (200a) positioned in the first through hole (120a) and a rotating shaft second portion (200b) positioned in the second through hole (120b), the rotating shaft second portion (200b) having an inner radial flow passage (222a); the rotating shaft includes a crank pin (230) disposed between the first portion (200a) and the second portion (200b); the crank pin (230) is connected to a connecting rod (240), the connecting rod (240) is connected to a movable piston (250) in a compression cylinder (260); The reciprocating compressor includes an oil pump (C), The reciprocating compressor is An axial flow motor comprising a rotor (300) having magnets (310) and a stator (400) having electric coils (410), the rotor (300) is fixed to the rotating shaft (200) by a bush (B), the stator (400) is fixed to the crankcase (100) by a fixing structure (420), and the bush (B) is located inside the rotor (300) when viewed in the radial direction of the rotating shaft (200); the rotor (300) and the stator (400) are separated by a first axial clearance (F1); the bush (B) disposed between the rotor (300) and the rotating shaft (200) and a radial bearing defined by an annular structure (610) disposed around a portion of the rotating shaft (200) where the inner radial flow passage (222a) is located are separated by a second axial clearance (F2c); the first axial clearance (F1) is adjustable between the rotor (300) and the stator (400) by slidingly fitting the rotor (300) together with the bush (B) onto the rotating shaft (200); The reciprocating compressor is characterized in that the second axial clearance (F2c) is adjustable between the bush (B) and the annular structure (610).

10. The reciprocating compressor according to claim 9, characterized in that the stator (400) is fixed to the crankcase (100) by the fixing structure (420).

11. 10. The reciprocating compressor according to claim 9, further comprising a first fluid dynamic radial bearing (500a) formed in a space between an inner circumferential surface of the first through hole (120a) and the first portion (200a) of the rotary shaft.

12. 10. The reciprocating compressor according to claim 9, further comprising a second fluid dynamic radial bearing (500b) formed in a space between an inner circumferential surface of the second through hole (120b) and the second portion (200b) of the rotary shaft.

13. 10. The reciprocating compressor according to claim 9, wherein the crankcase upper portion (100a) has a bearing hub (700), the first through hole (120a) is formed in the bearing hub (700), and the reciprocating compressor further comprises an axial bearing (600) arranged between the bearing hub (700) and the crank pin (230).

14. The reciprocating compressor according to claim 9, characterized in that the radial bearing is arranged around the rotating shaft (200), and the annular structure (610) protrudes from the stator (400) and is arranged around a portion of the rotating shaft (200).

15. The reciprocating compressor according to any one of claims 1 to 14, characterized in that the first axial clearance (F1) is formed by displacement of the rotor (30, 300) or the stator (40, 400), and the second axial clearances (F2a, F2b, F2c) are generated by displacement of the bush (B).

16. The reciprocating compressor according to any one of claims 1 to 15, characterized in that it comprises an oil pump (C) having a conical shape provided in an inner axial flow passage (21) of the rotating shaft (20, 200) or an oil pump having a conical shape provided in the rotor (30, 300).

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