CN112943615B

CN112943615B - Crankshaft and compressor

Info

Publication number: CN112943615B
Application number: CN202110188073.8A
Authority: CN
Inventors: 闫鹏举; 张心爱; 张大鹏; 黄纯浚
Original assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Current assignee: Gree Green Refrigeration Technology Center Co Ltd of Zhuhai
Priority date: 2021-02-18
Filing date: 2021-02-18
Publication date: 2022-05-27
Anticipated expiration: 2041-02-18
Also published as: CN112943615A

Abstract

The invention provides a crankshaft and a compressor, wherein the crankshaft comprises a long shaft, an eccentric part and a short shaft which are sequentially connected, the end surface of the short shaft is a thrust surface, an outer annular lubricating area and an inner annular lubricating area are arranged on the thrust surface, and the outer annular lubricating area is arranged around the inner annular lubricating area; the outer annular lubricating area is internally provided with a plurality of outer lubricating grooves which are arranged at intervals along the circumferential direction of the outer annular lubricating area; the inner annular lubrication area is internally provided with a plurality of inner lubrication grooves which are arranged at intervals along the circumferential direction of the inner annular lubrication area. When using, the thrust surface of bent axle and the fitting surface cooperation of cooperation part, when the bent axle rotated, the gas that lies in the thrust off-plate and lubricating oil got into between thrust surface and the fitting surface through a plurality of outer lubrication grooves and a plurality of interior lubrication grooves to form one deck fluid film, can avoid like this or reduced the contact and the direct friction of thrust surface and fitting surface, thereby reduced the wearing and tearing of bent axle and cooperation part, improved the performance of using the compressor of above-mentioned structure.

Description

Crankshaft and compressor

Technical Field

The invention relates to the technical field of compressors, in particular to a crankshaft and a compressor.

Background

During the operation of the rotor compressor, the eccentric part of the crankshaft is provided with a thrust surface, the thrust surface provides axial supporting force for the crankshaft assembly, and sliding friction is formed between the thrust surface of the crankshaft and the thrust block when the crankshaft rotates. The thrust surface not only bears the weight of the thrust surface but also bears the weight of the motor rotor at the upper end of the crankshaft, so that severe friction and abrasion exist between the thrust surface and the lower flange. Therefore, during the operation of the compressor, the abrasion between the thrust surface of the crankshaft and the thrust block is reduced, and the stable working state of the crankshaft is necessary to be ensured.

Disclosure of Invention

The invention provides a crankshaft and a compressor, which are used for reducing the abrasion of the crankshaft and a matching part.

In order to achieve the above object, according to one aspect of the present invention, there is provided a crankshaft comprising a long axis, an eccentric portion, and a short axis connected in this order, an end face of the short axis being a thrust face having an outer annular lubrication region and an inner annular lubrication region thereon, the outer annular lubrication region being disposed around the inner annular lubrication region; wherein the outer annular lubrication zone has a plurality of outer lubrication grooves therein, the plurality of outer lubrication grooves being spaced circumferentially of the outer annular lubrication zone; the inner annular lubrication area is internally provided with a plurality of inner lubrication grooves which are arranged at intervals along the circumferential direction of the inner annular lubrication area.

Further, the crankshaft is rotatably arranged, wherein two ends of the outer lubricating groove are respectively an outer oil inlet edge and an outer oil outlet edge, the outer oil inlet edge is located on the outer periphery of the thrust surface, and the outer oil outlet edge is located on the inner periphery of the outer annular lubricating area; in the rotation direction of the crankshaft, the oil outlet edge is positioned behind the oil inlet edge; the two ends of the inner lubricating groove are respectively an inner oil inlet edge and an inner oil outlet edge, the inner oil inlet edge is positioned on the outer periphery of the inner annular lubricating area, and the inner oil outlet edge is positioned on the inner periphery of the inner annular lubricating area; in the rotation direction of the crankshaft, the inner oil inlet edge is positioned behind the inner oil outlet edge.

Further, an outer peripheral edge of the thrust surface, an inner peripheral edge of the outer annular lubricating area, an outer peripheral edge of the inner annular lubricating area, and an inner peripheral edge of the inner annular lubricating area are concentric circles.

Further, the outer lubricating groove is provided with a first outer spiral edge and a second outer spiral edge which are arranged at intervals, and the first outer spiral edge and the second outer spiral edge are both positioned between the outer oil inlet edge and the outer oil outlet edge; the inner lubricating groove is provided with a first inner spiral edge and a second inner spiral edge which are arranged at intervals, and the first inner spiral edge and the second inner spiral edge are both positioned between the inner oil inlet edge and the inner oil outlet edge.

Further, the angle β 1 of the first outer helical edge is 11 ° to 19 °, and the angle of the second outer helical edge is 11 ° to 19 °; and/or the angle beta 2 of the first inner spiral edge is 5-13 degrees, and the angle of the second inner spiral edge is 5-13 degrees.

Furthermore, the distance between two end points of the outer oil inlet edge is L, the depth of the outer lubricating groove is H, and L/H is more than or equal to 1.1 and less than or equal to 1.7.

Furthermore, the depth of the external lubricating groove is H, and H is more than or equal to 3 mu m and less than or equal to 20 mu m.

Further, the distance between two end points of the outer oil inlet edge is L, the radius of the outer oil inlet edge is r1, and L/r1 is more than or equal to 0.3 and less than or equal to 0.6.

Further, the thrust surface has an outer annular sealing surface and an inner sealing surface, wherein the inner annular lubrication zone is disposed about the inner sealing surface and the outer annular sealing surface is located between the inner annular lubrication zone and the outer annular lubrication zone.

Furthermore, the distance between the outer annular lubricating area and the inner annular lubricating area is w, and w is more than or equal to 2.5mm and less than or equal to 6 mm.

According to another aspect of the present invention, there is provided a compressor including the crankshaft as described above.

Further, the compressor also comprises a lower flange and a cover plate, wherein the lower end face of the lower flange is matched with the upper end face of the cover plate, the short shaft penetrates through the lower flange, and the thrust face is abutted to the upper end face of the cover plate.

The technical scheme of the invention is applied to provide a crankshaft, which comprises a long shaft, an eccentric part and a short shaft which are sequentially connected, wherein the end surface of the short shaft is a thrust surface, an outer annular lubricating area and an inner annular lubricating area are arranged on the thrust surface, and the outer annular lubricating area is arranged around the inner annular lubricating area; the outer annular lubricating area is internally provided with a plurality of outer lubricating grooves which are arranged at intervals along the circumferential direction of the outer annular lubricating area; the inner annular lubricating area is internally provided with a plurality of inner lubricating grooves which are arranged at intervals along the circumferential direction of the inner annular lubricating area. When using, the thrust surface of bent axle and the fitting surface cooperation of cooperation part, when the bent axle rotated, the gas that lies in the thrust off-plate and lubricating oil got into between thrust surface and the fitting surface through a plurality of outer lubrication grooves and a plurality of interior lubrication grooves to form one deck fluid film, can avoid like this or reduced the contact and the direct friction of thrust surface and fitting surface, thereby reduced the wearing and tearing of bent axle and cooperation part, improved the performance of using the compressor of above-mentioned structure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic view showing a partial structure of a compressor provided in an embodiment of the present invention;

FIG. 2 shows a partial enlarged view of FIG. 1;

FIG. 3 illustrates a schematic diagram of a thrust face of the crankshaft of FIG. 1;

FIG. 4 shows a partial enlarged view of FIG. 3;

FIG. 5 shows the relationship between the value of the groove width ratio L/r1 of the outer lubrication groove in FIG. 4 and the fluid film pressure;

FIG. 6 shows the relationship between the helix angle and the gas film thickness of the outer lubrication groove of FIG. 4;

FIG. 7 shows a relationship between the value of the groove width-to-depth ratio L/H of the outer lubrication groove in FIG. 4 and the air film rigidity;

FIG. 8 shows the relationship between the helix angle and the leakage of the outer lubrication groove of FIG. 4;

FIG. 9 shows the relationship between the helix angle and the average coefficient of friction of the inner lubrication groove in FIG. 4.

Wherein the figures include the following reference numerals:

10. a long axis; 20. an eccentric portion; 30. a minor axis; 31. an outer annular seal surface; 32. an inner sealing surface; 40. an external lubrication groove; 41. an outer oil inlet edge; 42. the edge of the oil outlet; 43. a first outer helical edge; 44. a second outer helical edge; 50. an inner lubrication groove; 51. an inner oil inlet edge; 52. an inner oil outlet edge; 53. a first inner helical edge; 54. a second inner helical edge; 60. a lower flange; 70. and (7) a cover plate.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 to 9, an embodiment of the present invention provides a crankshaft, which includes a long shaft 10, an eccentric portion 20, and a short shaft 30 connected in sequence, an end surface of the short shaft 30 is a thrust surface, and the thrust surface has an outer annular lubrication region and an inner annular lubrication region, and the outer annular lubrication region is disposed around the inner annular lubrication region; wherein, a plurality of outer lubricating grooves 40 are arranged in the outer annular lubricating zone, and the plurality of outer lubricating grooves 40 are arranged at intervals along the circumferential direction of the outer annular lubricating zone; the inner annular lubrication region has a plurality of inner lubrication grooves 50 therein, and the plurality of inner lubrication grooves 50 are provided at intervals in the circumferential direction of the inner annular lubrication region.

Adopt this scheme, when using, the thrust face of bent axle and the fitting surface cooperation of cooperation part, when the bent axle rotated, and the gas that lies in the thrust face outward and lubricating oil got into between thrust face and the fitting surface through a plurality of outer lubrication grooves 40 and a plurality of interior lubrication grooves 50 to form one deck fluid film, avoided like this or reduced the contact and the direct friction of thrust face and fitting surface, thereby reduced the wearing and tearing of bent axle and cooperation part, improved the performance of the compressor that uses above-mentioned structure. Furthermore, the thrust surface is provided on the end surface of the stub shaft 30 instead of the end surface of the eccentric portion 20, so that the wear of the eccentric portion 20 can be reduced, and the compression effect is not affected.

Alternatively, both the outer lubrication groove 40 and the inner lubrication groove 50 are logarithmic spiral grooves. Namely, the outer lubrication groove 40 and the inner lubrication groove 50 extend along the logarithmic spiral respectively, which is beneficial to the flow of fluid and improves the lubrication effect.

In the present embodiment, the crankshaft is rotatably disposed, wherein the two ends of the outer lubrication groove 40 are an outer oil inlet edge 41 and an outer oil outlet edge 42, respectively, the outer oil inlet edge 41 is located at the outer periphery of the thrust surface, and the outer oil outlet edge 42 is located at the inner periphery of the outer annular lubrication region; in the rotation direction of the crankshaft, the outer oil outlet edge 42 is located behind the outer oil inlet edge 41; the two ends of the inner lubricating groove 50 are respectively an inner oil inlet edge 51 and an inner oil outlet edge 52, the inner oil inlet edge 51 is positioned on the outer periphery of the inner annular lubricating area, and the inner oil outlet edge 52 is positioned on the inner periphery of the inner annular lubricating area; the inner oil inlet edge 51 is located rearward of the inner oil outlet edge 52 in the rotational direction of the crankshaft. The lubricant or gas enters the outer lubricant groove 40 from the outer oil inlet edge 41 of the outer lubricant groove 40 and flows to the outer oil outlet edge 42, the outer lubricant groove 40 extends in the opposite direction (which can also be understood as the rotation direction) to the rotation direction of the crankshaft, which facilitates the fluid to enter the outer lubricant groove 40 and increase the fluid pressure, and then the fluid flows out from the periphery of the outer lubricant groove 40 to form a fluid film. Some of the fluid flowing out of the outer lubrication groove 40 flows from the inner oil inlet rim 51 of the inner lubrication groove 50 into the inner lubrication groove 50 and then to the inner oil outlet rim 52. The extending direction (which can also be understood as the rotation direction) of the inner lubrication groove 50 is opposite to the rotation direction of the crankshaft, and the fluid in the inner lubrication groove 50 flows out from the peripheral edge of the inner lubrication groove 50 to form a fluid film.

In the present embodiment, the outer peripheral edge of the thrust surface, the inner peripheral edge of the outer annular lubricating area, the outer peripheral edge of the inner annular lubricating area, and the inner peripheral edge of the inner annular lubricating area are concentric circles. Namely, the four peripheries are four circular rings with the same circle center and different diameters.

In the present embodiment, the outer lubrication groove 40 has a first outer spiral edge 43 and a second outer spiral edge 44 which are arranged at intervals, and the first outer spiral edge 43 and the second outer spiral edge 44 are both located between the outer oil inlet edge 41 and the outer oil outlet edge 42; the inner lubrication groove 50 has a first inner spiral edge 53 and a second inner spiral edge 54 which are arranged at intervals, and the first inner spiral edge 53 and the second inner spiral edge 54 are both positioned between the inner oil inlet edge 51 and the inner oil outlet edge 52. Thus, the outer lubricating groove 40 and the inner lubricating groove 50 are both spiral grooves, which is beneficial to the fluid flowing from the periphery of the thrust surface to the middle of the thrust surface and improves the lubricating effect.

In this embodiment, the corner of the first outer helical edge 43Degree beta₁Is 11 degrees to 19 degrees, and the angle of the second outer spiral edge 44 is 11 degrees to 19 degrees; and/or the angle beta of the first inner helical edge 53₂Is 5 degrees to 13 degrees, and the angle of the second inner spiral edge 54 is 5 degrees to 13 degrees. The angle of the first outer spiral edge 43 is an angle between a tangent at any point on the first outer spiral edge 43 and a ray passing through a pole and the point, wherein the pole is a vertex of an angular coordinate in a polar coordinate system. The angle of the second outer helical edge 44 is the angle between the tangent at any point on the second outer helical edge 44 and the ray passing through the pole and the point, where the pole is the vertex of the angular coordinate in the polar coordinate system. The angle of the first inner spiral edge 53 is the angle between the tangent at any point on the first inner spiral edge 53 and the ray passing through the extreme point and that point. By the angle limitation, a fluid film is formed more favorably, and the lubricating effect is improved.

In the embodiment, the distance between two end points of the outer oil inlet edge 41 is L, the depth of the outer lubricating groove 40 is H, wherein L/H is more than or equal to 1.1 and less than or equal to 1.7. Specifically, L is the distance between two points AB in fig. 4.

In the embodiment, the depth of the external lubricating groove 40 is H, and H is more than or equal to 3 mu m and less than or equal to 20 mu m.

Further, the distance between two end points of the outer oil inlet edge 41 is L, the radius of the outer oil inlet edge 41 is r1, wherein L/r1 is more than or equal to 0.3 and less than or equal to 0.6.

In the present embodiment, the thrust surface has an outer annular sealing surface 31 and an inner sealing surface 32, wherein an inner annular lubrication region is provided around the inner sealing surface 32 and the outer annular sealing surface 31 is located between the inner and outer annular lubrication regions. The outer annular sealing surface 31 and the inner sealing surface 32 can play a role in sealing, and reduce fluid leakage.

In the embodiment, the distance between the outer annular lubricating area and the inner annular lubricating area is w, and w is more than or equal to 2.5mm and less than or equal to 6 mm. This ensures a good sealing effect.

Another embodiment of the present invention provides a compressor including the crankshaft described above.

Specifically, the compressor further includes a lower flange 60 and a cover plate 70, wherein a lower end surface of the lower flange 60 and an upper end surface of the cover plate 70 are engaged, the stub shaft 30 passes through the lower flange 60, and the thrust surface abuts against the upper end surface of the cover plate 70. When the compressor is used, the thrust surface of the crankshaft is matched with the matching surface of the cover plate 70, when the crankshaft rotates, gas and lubricating oil which are positioned outside the thrust surface enter the space between the thrust surface and the matching surface through the outer lubricating grooves 40 and the inner lubricating grooves 50, so that a layer of fluid film is formed, the contact and direct friction between the thrust surface and the matching surface are avoided or reduced, the abrasion of the crankshaft and the cover plate 70 is reduced, and the performance of the compressor using the structure is improved. Furthermore, the thrust surface is provided on the end surface of the stub shaft 30 instead of the end surface of the eccentric portion 20, so that the wear of the eccentric portion 20 can be reduced, and the compression effect is not affected.

To facilitate understanding of the present solution, the following is further described.

Specifically, the helical grooves are arranged as shown in fig. 3 and 4, which include an inner helical groove (i.e., inner lubrication groove 50), an outer helical groove (i.e., outer lubrication groove 40), and so on. When the crankshaft rotates anticlockwise at high speed relative to the lower partition plate (namely the cover plate), the rotating direction of the double spiral grooves is right. The refrigerant gas and the lubricating oil move gradually from the outer diameter to the groove root along the spiral groove, the two-phase fluid consisting of the refrigerant and the lubricating oil is continuously compressed in the moving process, the pressure is continuously increased, and meanwhile, the fluid reaches the highest pressure value at the groove root due to the throttling effect generated by the sealing dam, so that two end faces are separated and a layer of extremely thin fluid film is formed. Due to the existence of hydrodynamic pressure, the bearing force between the thrust surfaces of the crankshaft is increased, and the pressure of the stator assembly on the crankshaft is reduced. And the two end surfaces are changed from a direct contact state to a non-contact state, so that the friction and the abrasion caused by the direct contact of the two end surfaces are reduced to a great extent, the service life of the crankshaft is prolonged, the fluid film has certain rigidity, the radial leakage of lubricating oil and a refrigerant can be prevented, the power consumption of the compressor is reduced, and the output of refrigerating capacity is increased.

Because of the existence of the spiral groove, a layer of fluid film with rigidity is formed between the thrust surface of the crankshaft and the end surface of the flange, and the bearing capacity and the rigidity of the film have a direct relation with the structural parameters of the spiral groove. When the crankshaft runs, the pretightening force of the lower flange screw and the hydrostatic pressure of the process medium form a closing force of the whole end face, and the closing force acts on the back face of the flange. The hydrodynamic pressure between the two end faces is the opening force of the two end faces and acts on the two sides of the crankshaft thrust face and the flange end face. When the crankshaft starts to operate, the rotating speed is low, the hydrodynamic pressure generated by the hydrodynamic grooves is low, the closing force is larger than the opening force, the two end faces are always in contact, the hydrodynamic pressure is increased along with the increase of the rotating speed, but the closing force is basically kept unchanged until the opening force is larger than the closing force, so that the lower flange moves axially, the gap between the two end faces is increased until the end face and the back face of the lower flange are balanced, a stable air film is formed between the end faces, and the effects of sealing and reducing the frictional wear between the end faces are achieved.

Fig. 3 shows a crankshaft thrust surface provided with hydrodynamic grooves, the rotational directions of which are set according to the rotational direction of the compressor crankshaft. As shown in the figure, if the rotation direction of the crankshaft is clockwise, the direction of the spiral groove is anticlockwise, so that the situation that gas gradually moves from the outer diameter to the root of the groove along the spiral groove in the high-speed operation process of the crankshaft can be guaranteed, the gas is continuously compressed in the moving process, the pressure is continuously increased, meanwhile, due to the throttling effect generated by the sealing dam, the gas reaches the highest value of the pressure at the root of the groove, the sealing end face is separated, and a gas film is formed, and the opening force is generated in the same way. The inside of the sealing dam is also provided with a series of spiral grooves which enable the fluid to rotate reversely, and the reverse spiral grooves play roles in reverse pumping and improving the pressure distribution of the matching surface, so that the capacity of opening the gap between the end face of the crankshaft and the contact surface of the flange is increased. The inner side of the reverse spiral groove is also provided with a section of sealing dam which generates resistance effect on the gas flow and increases the pressure of a gas film.

FIG. 4 is a schematic of a double helix flute helix angle and flute diameter. The angle of the spiral groove refers to the included angle between the tangent line at any point on the spiral curve and the line passing through the extreme point and the point. In this patent, the spiral angle of the outer lubrication groove (i.e., the angle of the first outer spiral edge 43 or the angle of the second outer spiral edge 44) ranges from 11 to 19 °, and the spiral angle of the inner lubrication groove (i.e., the angle of the first inner spiral edge 53 or the angle of the second inner spiral edge 54) ranges from 5 to 13 °. The range of the width-depth ratio L/H (the ratio of the groove width to the groove depth) of the outer spiral groove is 1.1-1.7, the width-depth ratio L/r1 of the outer spiral groove is 0.3-0.6, and the groove diameter of the outer spiral groove is selected according to the specific diameter of the end face of the crankshaft.

FIG. 5 is a graph showing the relationship between the ratio of the groove width to the groove depth of the outer spiral groove and the fluid film pressure. In the scheme, the depth of the outer spiral groove is 3-20 mu m, and when the width ratio of the outer spiral groove is 0.35-0.55, the fluid film pressure between the thrust surface of the crankshaft and the contact surface of the cover plate is obviously selected to be in other ranges, because the groove type of the outer spiral groove is structurally optimal in the range.

FIG. 6 is a graph showing the relationship between the angle of the external spiral and the thickness of the gas film. The application patent indicates that when the angle of the outer spiral groove is 12-18 degrees, the thickness of a fluid film between the thrust surface of the crankshaft and the end surface of the flange is obviously superior to that of other selected ranges, the thickness of the air film is 3-6 microns in the range of the spiral angle, and the air film has enough bearing capacity to push the two end surfaces away, so that the contact state of the two end surfaces is changed from direct contact to indirect contact, and the frictional wear between the end surfaces is reduced.

FIG. 9 is a graph of internal helix angle versus the average coefficient of friction between thrust surfaces. The application patent provides that when the inner spiral groove is at 6 degrees to 12 degrees, the average friction coefficient between the crankshaft thrust surface and the flange end surface reaches the minimum value, and in the angle range of the inner spiral groove, the reverse spiral grooves increase the capacity of opening the gap between the crankshaft end surface and the flange contact surface to the maximum value, so that the friction wear between the two end surfaces is the minimum, and the average friction coefficient between the end surfaces is the minimum.

FIG. 7 is a graph showing the relationship between the groove width-depth ratio L/H (ratio of groove width to groove depth) of the outer spiral groove and the gas film rigidity. In the patent, the rigidity of the fluid film formed by the bidirectional spiral groove of the thrust surface of the crankshaft is optimized when the width-depth ratio L/H of the external spiral groove is between 1.2 and 1.6.

The double-spiral groove structure provided by the scheme can enable a 3-5 mu m fluid film to be generated between the thrust surface and the contact surface of the partition plate when the crankshaft runs at a high speed, and the fluid film is not limited to an air film or a liquid film, but also can be a fluid film with coexistence of gas phase and liquid phase. Alternatively, the fluid film pressure reaches an optimum value when the ratio (groove width ratio) L/r1 of the groove width (linear distance between the points A and B) of the outer spiral groove to the groove diameter is between 0.35 and 0.55.

Alternatively, when the spiral angle (the angle between the tangent at any point on the spiral curve and the ray passing through the point) β of the outer spiral groove₁The thickness of the air film reaches the optimum value at 12 degrees to 18 degrees.

A fluid film is generated during the operation of the crankshaft, and the fluid film can change the direct contact state between the end faces into the indirect contact state, thereby reducing the friction and the abrasion between the two end faces. Alternatively, when the helix angle beta of the inner helical groove₂The friction coefficient between the crankshaft thrust surface and the contact surface of the partition plate is optimal at 6-12 degrees.

The fluid film has certain film rigidity, and when the groove width-depth ratio L/H (the ratio of the groove width to the groove depth) of the outer spiral groove is 1.2-1.6, the rigidity of the air film between the flange end face and the crankshaft thrust face is optimal. The presence of the fluid film can reduce leakage between the end faces, and when the angle of the external helix angle is 12.5 DEG to 16.5 DEG, the leakage between the end faces is the largest, and when the angle of the external helix angle is 17 DEG to 26 DEG, the leakage between the end faces is the optimum and the leakage amount is the smallest.

The spiral groove comprises an inner spiral groove and an outer spiral, and the friction coefficient between the thrust surface of the crankshaft and the contact surface of the partition plate is optimized when the radial distance w between the inner spiral groove and the outer spiral groove (the difference between the inner diameter r0 of the circle corresponding to the outer spiral groove and the outer diameter r2 of the circle corresponding to the inner spiral groove) is 2.5-6 mm.

The technical scheme includes that a logarithmic hydrodynamic groove is formed in a crankshaft thrust surface of a rotor compressor, the rotation direction of a spiral groove is set through the rotation direction of a crankshaft, gas enters the groove root through a spiral groove pump in the process of high-speed rotation of the crankshaft, a layer of microstructure gas film is formed between two end faces under the throttling action of a sealing dam, and the logarithmic spiral groove can be an arc groove, an L-shaped groove, a swallow-shaped groove, a U-shaped groove, a T-shaped groove and the like. The technical scheme of the invention applies to a two-stage compressor structure and can also be an implementation structure of a single-stage compressor.

The technical scheme of the invention solves the following technical problems: 1. aiming at a certain rotor type compressor, a crankshaft thrust part is designed at the contact surface of a crankshaft and a lower clapboard (namely a cover plate), so that the friction and the abrasion of the eccentric part of the crankshaft are reduced. 2. The two-way spiral groove structure is arranged on the thrust surface of the crankshaft, in the running process of the compressor, gas and lubricating oil in the pump body are pumped to the groove root under the action of the spiral groove through high-speed rotation of the crankshaft, the gas and the lubricating oil are accumulated at the groove root to form a layer of fluid film, and the fluid film has certain rigidity, so that frictional wear between two end surfaces can be reduced, and the bearing capacity of the end surface of the crankshaft can be improved. 3. Aiming at the problem that a bidirectional spiral groove structure is arranged on a thrust surface of a compressor, the width-diameter ratio (the ratio of the groove width to the groove diameter) of the spiral groove is found when the bearing capacity of a fluid film is optimal in the running process of the compressor. 4. The stability of a fluid film is considered, an optimal angle of an outer spiral groove (namely an outer lubricating groove) is selected, the thickness of a gas film between a thrust surface of a compressor crankshaft and a contact surface of a flange is most stable within the spiral angle range, and the fluid dynamic pressure effect of the spiral groove is optimal. 5. Considering the friction loss between the crankshaft thrust surface and the flange end surface, the optimal angle of the inner spiral groove (i.e. the inner lubrication groove) is selected, the friction coefficient between the crankshaft thrust surface and the flange contact surface is minimized in the angle, and the abrasion degree between the end surfaces is minimized. 6. And in the operation process of the compressor, leakage of refrigerant and lubricating oil between the thrust surface and the end surface of the cover plate is considered, an optimal outer spiral groove angle is selected, the leakage amount between the thrust surface and the end surface of the flange is minimum within the angle range, and the COP of the whole compressor is highest. COP is the ratio of the cooling capacity to the consumed power, which can also be understood as the efficiency of the compressor.

The scheme can produce the following beneficial effects:

1. this patent proposes to set up regular two-way fluid helicla flute structure on rotary compressor bent axle thrust surface, and through the high-speed operation of compressor, the root of helicla flute is inwards pumped to the outer gas of helicla flute and lubricating oil, and a section non-groove area outside the root becomes the sealed dam. The flow of the gas and the lubricating oil of the sealing dam generates a resistance effect, and the pressure of a gas film between the thrust surface and the bearing is increased.

2. The hydrodynamic groove is a logarithmic spiral groove structure with certain parameters, when the crankshaft rotates, the gas and the lubricating oil are pumped into the groove, the gas and the lubricating oil move along the groove root, and the fluid formed by the gas and the liquid flows in a decelerating way and is gradually compressed because of the obstruction of the sealing weir, the pressure of the fluid rises in the process, namely hydrodynamic pressure is generated, when the pressure reaches a certain value, the lower partition plate with flexible support is pushed away from the surface of the thrust surface of the crankshaft, so that a layer of extremely thin fluid film is always kept between the sealing surfaces, the formed fluid film can effectively separate the end surfaces to keep non-contact on one hand, the power loss of the compressor caused by frictional wear between the end surfaces is reduced, on the other hand, the two end surfaces which run relatively are cooled, the service life of the crankshaft is prolonged, and the overall efficiency of the compressor is improved.

3. In the process of high-speed operation of the crankshaft, a fluid film with certain rigidity is generated between the thrust surface of the crankshaft and the contact surface of the lower partition plate due to the double spiral grooves, the fluid film can effectively control leakage between the two end surfaces, leakage of lubricating oil and refrigerant is reduced, and the integral COP of the compressor is improved.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A crankshaft, characterized by comprising a long shaft (10), an eccentric part (20) and a short shaft (30) which are connected in sequence, wherein the end surface of the short shaft (30) is a thrust surface, the thrust surface is provided with an outer annular lubricating area and an inner annular lubricating area, and the outer annular lubricating area is arranged around the inner annular lubricating area; wherein the content of the first and second substances,

the outer annular lubricating zone is internally provided with a plurality of outer lubricating grooves (40), and the outer lubricating grooves (40) are arranged at intervals along the circumferential direction of the outer annular lubricating zone;

the inner annular lubricating area is internally provided with a plurality of inner lubricating grooves (50), and the inner lubricating grooves (50) are arranged at intervals along the circumferential direction of the inner annular lubricating area;

the crankshaft is rotatably provided, wherein,

the two ends of the outer lubricating groove (40) are respectively an outer oil inlet edge (41) and an outer oil outlet edge (42), the outer oil inlet edge (41) is positioned on the outer periphery of the thrust surface, and the outer oil outlet edge (42) is positioned on the inner periphery of the outer annular lubricating area; in the rotation direction of the crankshaft, the oil outlet edge (42) is positioned behind the oil inlet edge (41);

the two ends of the inner lubricating groove (50) are respectively an inner oil inlet edge (51) and an inner oil outlet edge (52), the inner oil inlet edge (51) is positioned on the outer periphery of the inner annular lubricating area, and the inner oil outlet edge (52) is positioned on the inner periphery of the inner annular lubricating area; in the rotation direction of the crankshaft, the inner oil inlet edge (51) is positioned behind the inner oil outlet edge (52).

2. The crankshaft of claim 1, wherein an outer periphery of said thrust surface, an inner periphery of said outer annular lubrication region, an outer periphery of said inner annular lubrication region, and an inner periphery of said inner annular lubrication region are concentric circles.

3. A crankshaft according to claim 1,

the outer lubricating groove (40) is provided with a first outer spiral edge (43) and a second outer spiral edge (44) which are arranged at intervals, and the first outer spiral edge (43) and the second outer spiral edge (44) are both positioned between the outer oil inlet edge (41) and the outer oil outlet edge (42);

the inner lubricating groove (50) is provided with a first inner spiral edge (53) and a second inner spiral edge (54) which are arranged at intervals, and the first inner spiral edge (53) and the second inner spiral edge (54) are both positioned between the inner oil inlet edge (51) and the inner oil outlet edge (52).

4. A crankshaft according to claim 3,

angle beta of said first outer helical edge (43)₁Is 11 DEG to 19 DEG, the angle of the second outer helical edge (44) is 11 DEG to 19 DEG; and/or the presence of a gas in the gas,

angle beta of the first inner helical edge (53)₂Is 5 DEG to 13 DEG, and the angle of the second inner spiral edge (54) is 5 DEG to 13 deg.

5. A crankshaft according to claim 1, characterized in that the distance between the two end points of the outer oil inlet rim (41) is L and the depth of the outer lubrication groove (40) is H, wherein L/H is more than or equal to 1.1 and less than or equal to 1.7.

6. A crankshaft according to claim 1, characterized in that the depth of the outer lubrication groove (40) is H, 3 μm ≦ H ≦ 20 μm.

7. A crankshaft according to claim 1, characterized in that the distance between the two end points of the outer oil inlet rim (41) is L, the radius of the outer oil inlet rim (41) is r1, wherein L/r1 is 0.3 ≤ L/r1 ≤ 0.6.

8. A crankshaft according to claim 1, characterized in that the thrust surface has an outer annular sealing surface (31) and an inner sealing surface (32), wherein the inner annular lubrication zone is arranged around the inner sealing surface (32) and the outer annular sealing surface (31) is located between the inner annular lubrication zone and the outer annular lubrication zone.

9. A crankshaft according to claim 1, wherein the spacing between the outer and inner annular lubrication regions is w, 2.5mm ≦ w ≦ 6 mm.

10. A compressor, characterized in that it comprises a crankshaft according to any one of claims 1 to 9.

11. The compressor of claim 10, further comprising a lower flange (60) and a cover plate (70), wherein a lower end surface of the lower flange (60) and an upper end surface of the cover plate (70) are mated, the stub shaft (30) passes through the lower flange (60), and the thrust surface abuts the upper end surface of the cover plate (70).