An integrated dry oil-free screw main unit and its gear box

Abstract

The present invention discloses an integrated dry oil-free screw main unit and its gearbox, which belongs to the technical field of compressor oil mist treatment. The gearbox in the integrated dry oil-free screw main unit includes a gearbox housing and an input shaft, wherein a gear transmission group is installed inside the gearbox housing, one end of the input shaft is fixedly connected to the output end of the driving mechanism, and the other end of the input shaft extends into the gearbox housing, which drives the screw rotors in the high-pressure head and the low-pressure head through the gear transmission group; the supporting bearing, the primary separator, and the centrifugal impeller are located inside the gearbox housing, and are sequentially mounted on the outside of the input shaft along the flow direction of the oil mist channel, wherein the centrifugal impeller is fixedly connected to the input shaft. By integrating the oil mist treatment mechanism inside the gearbox, this solution can efficiently treat the oil mist in the gearbox and prevent the oil mist in the gearbox from infiltrating into the oil-free rotor compression chamber.

Description

Technical Field

[0001] The invention relates to the technical field of compressor oil mist treatment, and more specifically to an integrated dry oil-free screw main unit and a gear box thereof. Background Art

[0002] In the field of dry oil-free screw compressors, the air compression process in the screw rotor is oil-free, but the bearings and gears outside the rotor compression chamber need oil lubrication, so a variety of sealing structures are used in the design to prevent oil from entering the oil-free compression chamber. Since there is no oil lubrication during the air rotor compression process, the volumetric efficiency of the dry oil-free screw compressor is very low. The volumetric efficiency of the compressor can be improved by increasing the rotor speed. Therefore, the rotor speed of the dry oil-free screw compressors on the market is basically over 10,000 revolutions. As a result, the transmission gears in the speed change gearbox and the rotor precision synchronous gears in the main engine will form a large amount of oil mist during operation due to the high-speed extrusion of the lubricating oil film and the high-speed centrifugal impact splashing. If these oil mists cannot be effectively treated, they will leak out and cause environmental pollution. In addition, the increase in the oil temperature inside the gearbox will cause positive pressure inside the gearbox. When the gearbox is in a positive pressure state, the oil mist may penetrate into the oil-free rotor compression chamber through the sealing component, causing the compressed air to be contaminated.

[0003] If the oil mist of the gearbox is discharged directly into the atmosphere, it will cause air pollution; it will also cause a reduction in the system lubricating oil, which will have an adverse effect on subsequent lubrication. The existing gearbox oil mist treatment method generally sets an oil mist treatment device connected to the gearbox outside. This treatment method requires an external power source, such as electricity, compressed air, etc. On the other hand, due to the complexity of the external equipment, the size of the compressor main unit will increase and the cost will be higher.

[0004] For example, the Chinese patent with application number 2022219008217 discloses an electric oil mist collector for a dry screw air compressor, which includes a recovery box, an oil mist filter element and a fan. The recovery box has an oil mist air inlet, and the oil mist filter element is arranged in the recovery box. The oil mist filter element is connected to the oil mist air inlet and is used to communicate with the dry screw main engine through the oil mist air inlet. The bottom of the recovery box has an oil return port, which is used to communicate with the main engine oil tank. The oil mist filter element is used to filter the oil mist and form oil droplets, so that the oil droplets are recovered into the main engine oil tank through the oil return port. The top of the recovery box has an exhaust port, and the fan is arranged in the recovery box so that the clean air in the recovery box is discharged to the atmosphere through the exhaust port. Although this application can effectively solve the oil mist treatment problem of the dry compressor, it can better prevent the oil mist from entering the gas compression chamber or the atmosphere through the body sealing structure. However, this application still belongs to the oil mist processor connected to the gearbox.

[0005] For another example, the Chinese patent application number is 2010202686484, which discloses an oil mist separation device for an oil-free screw compressor gearbox, which includes a shell and an oil mist separation core, the oil mist separation core is installed in the cavity of the shell, and the shell is provided with a purified air outlet communicating with the shell cavity, and the shell is also provided with a pressurized air inlet channel and an oil mist inlet communicating with the compressor exhaust pipeline, one end of the oil mist inlet is communicated with the inner cavity of the gearbox, and the other end is communicated with the pressurized air inlet channel, a nozzle is installed in the pressurized air inlet channel, the nozzle extends into the air inlet of the inner joint, a gap of 2-3 mm is provided between the nozzle and the air inlet of the inner joint, the gap is communicated with the oil mist inlet, and the air outlet of the inner joint is communicated with the air inlet of the oil mist separation core; an oil drain hole communicating with its inner cavity is also provided on the shell, and the oil drain hole is communicated with the oil receiving pipe. This application uses the compressed air generated by the compressor itself as power, and generates negative pressure around the nozzle through high-speed injection to suck the oil mist into the filter element. However, this application also belongs to the oil mist processor connected to the gear box.

[0006] For another example, the Chinese patent application number is 2023206179255. This application discloses an oil mist separation device for a compressor gearbox, which includes a primary separation cylinder, a centrifugal motor is fixedly connected to the left side of the primary separation cylinder, a rotating shaft is fixedly connected to the output end of the centrifugal motor, the rotating shaft is rotatably connected to the inside of the primary separation cylinder, at least one centrifugal blade is fixedly connected to the surface of the rotating shaft, at least one reinforcement ring is fixedly connected to the middle of the centrifugal blade, and a through hole is opened on the surface of the reinforcement ring. A separation ring plate is fixedly connected to the inside of the primary separation cylinder, and at least one oil leakage hole is opened on the surface of the separation ring plate. An annular cavity is formed between the separation ring plate and the inner wall of the primary separation cylinder, and a wind-blocking arc plate is fixedly connected to the inner surface of the separation ring plate. A connecting pipe is fixedly connected to the right side of the primary separation cylinder. A secondary separation cylinder is fixedly connected to the right end of the connecting pipe. This application sets up a two-stage separation cylinder to reduce the separation pressure of the secondary separation cylinder, which is conducive to improving the recovery efficiency of oil mist, but this application also belongs to an oil mist processor connected to the gearbox. Summary of the invention

[0007] 1. Technical problems to be solved

[0008] In view of the technical problem that in the prior art, an oil mist treatment device connected to the gearbox is usually required to be arranged outside the gearbox, resulting in a large compressor host and the need for external connection, the present invention provides an integrated dry oil-free screw host and its gearbox. By integrating the oil mist treatment mechanism inside the gearbox, the solution can efficiently treat the oil mist in the gearbox and prevent the oil mist in the gearbox from penetrating into the oil-free rotor compression chamber through the sealing component.

[0009] 2. Technical solution

[0010] In order to achieve the above object, the technical solution provided by the present invention is:

[0011] The first aspect of the present invention provides an integrated dry oil-free screw main engine gearbox, which includes a gearbox housing and an input shaft, a gear transmission mechanism is installed inside the gearbox housing, one end of the input shaft is fixedly connected to the output end of the driving mechanism, and the other end of the input shaft extends into the gearbox housing, which drives the screw rotors in the high-pressure head and the low-pressure head to move through the gear transmission group; the supporting bearing, the primary separator, and the centrifugal impeller are all installed inside the gearbox housing, and are sequentially mounted on the outside of the input shaft along the flow direction of the oil mist channel, wherein the centrifugal impeller is fixedly connected to the input shaft.

[0012] Furthermore, the primary separator includes a separator outer ring and a separator inner ring, the input shaft is sleeved inside the separator inner ring and there is a gap between the input shaft and the separator inner ring; the separator outer ring and the separator inner ring are fixedly connected by a plurality of parallel and spaced baffles, a baffle channel is formed between adjacent baffles, and a first oil collecting tank connected to the baffle channel is provided in the separator outer ring, and the first oil collecting tank is connected to the oil collecting tank of the gear box air inlet.

[0013] Furthermore, the separator outer ring and the separator inner ring are fixedly connected by a plurality of parallel and spaced baffles, a baffle channel is formed between adjacent baffles, and a first oil collecting tank connected to the baffle channel is provided in the separator outer ring, and the first oil collecting tank is connected to the oil collecting tank of the gear box air inlet.

[0014] Furthermore, the deflector plates include a deflector main plate extending along the axial direction of the input shaft, and deflector baffles are arranged on both sides of the deflector main plate at staggered intervals, and the inner side surface thereof and the outer side surface of the deflector baffle form a V-shaped groove, and the opening of the V-shaped groove is 40 to 60°, and the deflector baffles of adjacent deflector main plates are staggered with each other along the axial direction of the input shaft.

[0015] Furthermore, the first oil collecting groove includes a radial oil collecting groove and a plurality of axial oil collecting grooves perpendicular to the radial oil collecting groove and arranged in a ring shape and in parallel. The axial oil collecting groove extends along the axial direction of the input shaft and passes through the outer ring of the separator and is connected to the deflection channel. The radial oil collecting groove extends along the circumferential direction of the outer ring of the separator and connects the plurality of axial oil collecting grooves.

[0016] Furthermore, one end of the primary separator is in contact with the outer ring of the support bearing, and the other end of the primary separator is axially fixed by a retaining ring.

[0017] Furthermore, at least two limit blocks are provided on the outer side of the primary separator and are spaced apart along the circumferential direction thereof, and the limit blocks are installed in the oil collecting tank of the air inlet of the gear box.

[0018] Furthermore, the centrifugal impeller includes a coaxially arranged impeller inner ring and an upper ring piece, the input shaft is sleeved inside the impeller inner ring and fixedly connected to the impeller inner ring; one end of the impeller inner ring extends radially to form a lower ring piece; the upper ring piece is located at the other end of the impeller inner ring, and an annular impeller air inlet groove is formed between the two; a plurality of impeller blades distributed along annular intervals are provided between the lower ring piece and the upper ring piece.

[0019] Furthermore, a secondary separator is provided inside the gearbox on one side of the input shaft, and the exhaust end of the centrifugal impeller is connected to the intake end of the secondary separator through an exhaust connection hole.

[0020] Furthermore, it also includes a gland for confining the secondary separator inside the gearbox housing, and a gland adjustment port corresponding to the exhaust connection hole is opened on one side of the top of the gland, wherein the diameter of the gland adjustment port facing the exhaust connection hole can be adjusted.

[0021] Furthermore, the top of the gland is provided with two shell connecting holes symmetrically arranged along the circumferential direction, and the shell connecting holes are waist-shaped holes.

[0022] Furthermore, the oil collecting tank of the secondary separator is communicated with the oil collecting tank of the gear box air inlet.

[0023] Furthermore, the secondary separator is a precision oil separator core.

[0024] A second aspect of the present invention provides an integrated dry oil-free screw main unit, comprising a high-pressure die head, a low-pressure die head and the above-mentioned gear box.

[0025] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0026] (1) The present invention integrates the oil mist treatment function inside the gearbox by sequentially mounting the support bearing, the primary separator, and the centrifugal impeller on the outside of the input shaft along the flow direction of the oil mist channel. Specifically, the centrifugal impeller rotates with the input shaft, driving the oil mist flow in the gearbox, and the primary separator separates the gas with a large amount of oil mist to reduce the content of oil mist particles in the gas, thereby not only achieving the treatment of oil mist, but also eliminating the need for an external air source or other power source, thereby increasing the efficiency of machine use and reducing costs. At the same time, the compressor main unit does not require an external oil mist treatment device, making it more simple and beautiful. In addition, the amount of oil mist treated by the centrifugal impeller is large, so that the oil mist in the gearbox is kept at a low level.

[0027] (2) The present invention further adds a secondary separator downstream of the centrifugal impeller to separate the oil mist of the gearbox again, so that the separated gas is cleaner. Furthermore, the oil mist separated by the primary separator and the secondary separator flows back to the gearbox, reducing the loss of lubricating oil. The oil mist treatment system circulates inside the gearbox and is not directly discharged into the atmosphere, preventing environmental pollution.

[0028] (3) The present invention further optimizes the design of the oil mist flow channel between the centrifugal impeller and the secondary separator. The gland not only fixes the secondary separator in the gear box housing, but also has a gland adjustment port on its outer wall. The air inlet diameter of the gland adjustment port can be adjusted. The oil mist passes through the centrifugal impeller, the gland adjustment port, and the secondary separator in sequence, thereby controlling the slight difference between the air intake and exhaust volume of the gear box, thereby maintaining the interior of the gear box in a slight negative pressure state, thereby preventing the oil mist from escaping and leaking. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the three-dimensional structure of the integrated dry oil-free screw main unit in an embodiment of the present invention.

[0030] Figure 2 In the embodiment of the present invention Figure 1 Schematic cross-sectional view at AA in the middle.

[0031] Figure 3 It is a schematic diagram of the three-dimensional structure of the primary separator in an embodiment of the present invention.

[0032] Figure 4 It is a cross-sectional schematic diagram of a primary separator in an embodiment of the present invention.

[0033] Figure 5 Schematic diagram of the three-dimensional structure of the centrifugal impeller in an embodiment of the present invention.

[0034] Figure 6 Schematic diagram of the cross-sectional structure of the centrifugal impeller in the embodiment of the present invention.

[0035] Figure 7 It is a schematic diagram of the three-dimensional structure of the gland in an embodiment of the present invention.

[0036] Figure 8 In the embodiment of the present invention Figure 2 Schematic cross-sectional view at the middle BB.

[0037] Fig. 9 In the embodiment of the present invention Figure 8 Enlarged schematic diagram of the Z point in the middle.

[0038] Description of labels:

[0039] 1. Input shaft;

[0040] 2. The first driving gear;

[0041] 3. Gearbox housing; 301. Exhaust connection hole; 302. First connecting oil groove; 303. Second connecting oil groove;

[0042] 4. High-pressure handpiece; 401. First branch;

[0043] 5. Low pressure head; 502. Second branch;

[0044] 6. Centrifugal impeller; 601. Upper ring piece; 602. Impeller blade; 603. Impeller inner ring; 604. Lower ring piece; 605. Input shaft connecting hole;

[0045] 7. Primary separator; 701. baffle plate; 7011. baffle main plate; 7012. baffle plate; 702. first oil collecting groove; 7021. radial oil collecting groove; 7022. axial oil collecting groove; 703. separator inner ring; 704. separator outer ring; 705. stop block;

[0046] 8. Secondary separator;

[0047] 9. Sealing cover plate;

[0048] 10. gland; 101. gland adjustment port; 102. shell connection hole;

[0049] 11. Support bearing;

[0050] 12. Oil mist inlet;

[0051] 13. Oil mist exhaust port. DETAILED DESCRIPTION

[0052] In order to further understand the content of the present invention, the present invention is described in detail in conjunction with the accompanying drawings and embodiments.

[0053] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportion relationship or adjustment of the size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and so on quoted in this specification are only for the convenience of description, and are not used to limit the scope of implementation. The change or adjustment of their relative relationship should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0054] The present invention provides an integrated dry oil-free screw main engine gearbox, referring to Figure 1, Figure 2 As shown, a gear transmission group is installed inside the gearbox housing 3, one end of the input shaft 1 is fixedly connected to the output end of the driving mechanism, and the other end of the input shaft 1 extends into the gearbox housing 3, which drives the screw rotors in the high-pressure head and the low-pressure head to move through the gear transmission group. The support bearing 11, the primary separator 7, and the centrifugal impeller 6 are all installed inside the gearbox housing 3, and are sequentially mounted on the outside of the input shaft 1 along the flow direction of the oil mist channel, wherein the centrifugal impeller 6 is fixedly connected to the input shaft 1.

[0055] In the gearbox for the dry screw main unit, the above-mentioned driving mechanism generally adopts a driving motor, and the output end of the driving motor is fixedly connected to the end of the input shaft 1 located outside the gearbox housing 3, thereby driving the input shaft 1 to rotate, and then providing input power for the dry screw main unit. The gear transmission group includes a first driving gear 2, and the first driving gear 2 is fixedly sleeved on the outside of the input shaft 1. The first driving gear 2 meshes with other gears to transmit power to the screw rotors in the low-pressure head 4 and the high-pressure head 5, thereby providing power for the screw rotor to compress air. It should be understood that there are many specific implementation methods for the first driving gear 2 to transmit power to the screw rotor. The specific structure of the first driving gear 2 transmitting power to the low-pressure head 4 and the high-pressure head 5 is selected as the existing technology and will not be described in detail here.

[0056] In dry screw compressors, refer to Figure 2 As shown, the gearbox housing 3 is provided with an oil mist inlet 12 and an oil mist exhaust port 13, and a connected oil mist flow channel is formed between the oil mist inlet 12 and the oil mist exhaust port 13. For specific flow direction, refer to Figure 2 The flow trajectory indicated by f.

[0057] It should be understood that the oil mist inlet 12 and the oil mist exhaust 13 are provided in the gearbox, and the oil mist inlet 12 refers to the oil mist inlet, and the oil mist inlet 12 is not necessarily limited to the starting point of the oil mist channel inside the gearbox, and the oil mist inlet 12 is located upstream of the support bearing 11 in the input shaft 1 along the flow direction of the oil mist channel. The oil mist exhaust 13 refers to the gas discharge port after separation by the oil mist primary separator, and the oil mist exhaust 13 is not necessarily the end point of the oil mist channel inside the gearbox; the oil mist exhaust 13 is located downstream of the centrifugal impeller 6 along the flow direction of the oil mist channel.

[0058] The integrated dry oil-free screw main engine gearbox, wherein the oil mist treatment process is as follows: the centrifugal impeller 6 rotates together with the input shaft 1, and the centrifugal impeller 6 rotates to generate negative pressure, which can drive the oil mist body inside the gearbox to flow without the need for an external air source or other power. The primary separator 7 separates the oil mist flowing through here. In addition, since the primary separator 7 is located between the centrifugal impeller 6 and the support bearing 11, the oil mist flowing through the support bearing 11 is unseparated flowing oil mist, which can have a good lubrication and cooling effect on the support bearing 11, greatly improving the service life of the support bearing 11.

[0059] As a preferred embodiment of the primary separator 7, Figure 3 , Figure 4 As shown, the primary separator 7 includes a separator outer ring 704 and a separator inner ring 703 which are coaxially arranged, the input shaft 1 is sleeved inside the separator inner ring 703 and there is a gap between the input shaft 1 and the separator inner ring 703; the separator inner ring 703 and the separator outer ring 704 are fixedly connected by a plurality of parallel and spaced baffles 701, a baffle channel is formed between adjacent baffles 701, a first oil collecting groove 702 which is connected to the baffle channel is provided in the separator outer ring 704, and the first oil collecting groove 702 is connected to the oil collecting groove of the gearbox air inlet 12. More specifically, a first connecting oil groove 302 is provided in the inner wall of the gearbox housing 3, and the two ends of the first connecting oil groove 302 are respectively connected to the first oil collecting groove 702 and the oil collecting groove of the gearbox air inlet 12. By opening the first connecting oil groove 302 in the inner wall of the gearbox housing 3 , the lubricating oil collected in the first connecting oil groove 302 will not be blocked by the outer ring of the support bearing 11 , and can smoothly flow back to the oil collecting groove of the gearbox air inlet 12 .

[0060] Further preferably, reference Figure 4 As shown, the plurality of baffles 701 all include a baffle main plate 7011 extending along the axial direction of the input shaft 1, and baffle baffles 7012 are arranged on both sides of the baffle main plate 7011 at staggered intervals, and the inner side surface thereof and the outer side surface of the baffle baffle 7012 form a V-shaped groove, and the opening of the V-shaped groove is 40-60°. The opening direction of the above-mentioned V-shaped groove is consistent, and when installed, the opening of the V-shaped groove between the baffle baffle 7012 and the baffle main plate 7011 is arranged directly in the direction of oil mist flow, so as to achieve a better separation effect on the oil mist.

[0061] It should be understood that there are multiple implementations of arranging the baffle plates 7012 of the baffle plates 7011 on both sides of the baffle plates 7011. For example, the baffle plates 7012 can be symmetrically arranged on both sides of the baffle plates 7011, and the baffle plates 7012 in adjacent baffle plates 7011 are staggered along the axis direction of the input shaft 1; or the cross connection points between the baffle plates 7012 and the baffle plates 7011 can also be arranged at intervals along the axis direction of the input shaft 1. Further, the baffle plates 7012 can be flat plates or curved plates, and the baffle plates 7011 can be flat plates, curved corrugated plates or curved plates, or other existing baffle plates with baffle functions can also be used.

[0062] Furthermore, 5 to 7 mutually staggered baffles 7012 are arranged between two adjacent baffle main boards 7011 along the axial direction of the input shaft 1, and correspondingly, 3 to 4 baffles 7012 are arranged on one side of each baffle main board 7011. An oil mist baffle channel with multiple S-shaped bends is formed between the corresponding baffle baffles 7012 between the adjacent baffle main boards 7011, so that the oil mist flowing therethrough changes its flow direction multiple times, thereby increasing the number of oil mist separations and extending the separation distance, so that the oil mist is separated more thoroughly.

[0063] The oil mist separation process of the primary separator 7 is as follows: when the oil mist passes between adjacent baffle main boards 7011, under the dual effects of gravity and the baffle 701 structure, it collides with the baffle plate 7012 to change its flow direction, and the oil mist particles collide and fold, causing the oil mist particles to increase in size. The increased oil mist particles will be adsorbed inside the V-shaped groove while the gas continues to flow, thereby separating the oil mist particles from the gas, and these oil mist particles will gather in the first oil collecting tank 702 connected to the baffle 701.

[0064] Regarding the preferred embodiment of the first oil collecting tank 702, refer to Figure 3 , Figure 8 As shown, the first oil collecting groove 702 includes a radial oil collecting groove 7021 and a plurality of axial oil collecting grooves 7022 which are perpendicular to the radial oil collecting groove 7021 and arranged in parallel and at intervals. The axial oil collecting groove 7022 extends along the axis of the input shaft 1 and penetrates the separator outer ring 704 and is connected with the baffle channel. The radial oil collecting groove 7021 extends along the circumferential direction of the separator outer ring 704 and is connected with the plurality of axial oil collecting grooves 7022. The oil mist particles in the V-shaped groove in the baffle plate 701 are collected into the axial oil collecting groove 7022 under the action of gravity, and the oil droplets in the axial oil collecting groove 7022 are then collected into the oil collecting groove of the gearbox air inlet through the radial oil collecting groove 7021, and finally flow into the gearbox to realize the oil mist circulation.

[0065] More preferably, the baffle plate 701 is a metal baffle plate, which can not only improve the oil mist separation efficiency, but also achieve lifelong maintenance-free, thereby reducing the production and use costs.

[0066] Regarding the preferred embodiment of the installation of the preliminary separator 7, one end of the primary separator 7 is in contact with the outer ring of the support bearing 11, and the retaining ring is preferably an elastic retaining ring. The gearbox housing 3 is correspondingly provided with a groove for placing the above retaining ring. One end of the primary separator 7 is in contact with the outer ring of the support bearing 11 to achieve axial fixation of one end of the primary separator 7, thereby reducing the number of grooves opened inside the gearbox housing 3. More specifically, the other end of the primary separator 7 and the other end of the support bearing 11 are axially fixed by a retaining ring, and the retaining ring is preferably an elastic retaining ring.

[0067] Further preferably, at least two stop blocks 705 are arranged at intervals along the circumferential direction of the primary separator 7 in the middle and outer sides thereof, and the stop blocks 705 are installed in the oil collecting groove of the air inlet of the gear box, so as to limit the axis of the primary separator 7 to be parallel to the axis of the oil collecting groove of the air inlet. Specifically, the stop blocks 705 are arranged on the outer wall of the separator outer ring 704.

[0068] In some embodiments, reference Figure 5 , Figure 6 As shown, the centrifugal impeller 6 includes a coaxially arranged impeller inner ring 603 and an upper ring piece 601, and the input shaft 1 is sleeved on the impeller inner ring 603 and fixedly connected to the impeller inner ring 603; wherein, one end of the impeller inner ring 603 extends along the radial outer ring to form a lower ring piece 604; the upper ring piece 604 is located at the other end of the impeller inner ring 603, and an annular impeller air inlet groove is formed between the two; a plurality of impeller blades 602 distributed along annular intervals are provided between the lower ring piece 604 and the upper ring piece 601.

[0069] As the centrifugal impeller 6 rotates, a gas flow channel is formed between the multiple impeller blades 602, and the air in the gas flow channel moves outward under the action of centrifugal force, thereby generating a vacuum in the center of the centrifugal impeller 201. Under the action of the vacuum, the oil mist is sucked into the impeller air inlet groove, and the sucked oil mist is turned 90° at the entrance of the impeller blade 602 and enters the gas flow channel formed by the blades. Under the action of the impeller blade 602, it obtains kinetic energy and pressure energy and continues to move along the oil mist channel. It should be noted that by designing the air inlet groove of the centrifugal impeller 6 to be annular, not only can the oil mist be sucked in more evenly and stably, but also the support bearing 11 located upstream of it along the flow direction of the oil mist can be more fully lubricated, and the primary separator 7 can separate more efficiently.

[0070] It should be noted that the centrifugal impeller 6 not only drives the oil mist of the gear box housing 3 to be oriented, but also when the oil mist passes through the centrifugal impeller 6, the oil mist particles are thrown toward the inner wall of the gear box housing 3 under the action of the centrifugal force of the impeller blades 602, thereby separating the oil mist again; the separated oil mist flows downward along the inner wall surface of the housing and returns to the oil collecting tank of the gear box air inlet 12.

[0071] It should be noted that the air volume of the centrifugal impeller 6 is very large, far greater than the amount of oil mist generated, so the oil mist concentration inside the gearbox housing 3 will be maintained in a relatively low range, greatly reducing the impact of the oil mist problem on the screw compression cavity.

[0072] In other embodiments, regarding the preferred implementation mode in which the input shaft 1 is sleeved on the impeller inner ring 603 and fixedly connected to the impeller inner ring 603, the impeller inner ring 603 is provided with two keyways symmetrically distributed along the circumferential direction of its inner wall, the input shaft 1 is provided with corresponding keyways, and the impeller inner ring 603 and the input shaft 1 are transmission connected via two flat keys symmetrically distributed along the circumferential direction, thereby realizing that the input shaft 1 drives the centrifugal impeller 6 to rotate.

[0073] Furthermore, the end of the centrifugal impeller 6 is also installed at the end of the input shaft 1 through a connecting bolt, so as to further improve the connection stability between the centrifugal impeller 6 and the input shaft 1. Specifically, an internal threaded hole along the axial direction of the input shaft 1 is provided at one end of the input shaft 1 connected to the centrifugal impeller 6, and accordingly, an input shaft connecting hole 605 for the connecting bolt to pass through is provided at the center of the lower ring plate 604, and the hole diameter of the input shaft connecting hole 605 is smaller than the outer diameter of the input shaft 1. The connecting bolt passes through the input shaft connecting hole 605 to lock the lower ring plate 604 on the lower ring plate 604, thereby increasing the stability of the connection between the two, and there is no need to add an additional shoulder on the input shaft 1 to limit the axial position of the centrifugal impeller.

[0074] In the gearbox housing 3, in order to seal the open end of the installation cavity for installing the input shaft, a sealing cover plate 9 is arranged opposite to the installation cavity of the input shaft 1 inside the gearbox, and is used to seal the opening of the gearbox housing 3. After removing the sealing cover plate 9, the centrifugal impeller 6 can be removed.

[0075] As a further preference of any of the above embodiments, a secondary separator 8 is further provided inside the gearbox on one side of the input shaft 1, and the exhaust end of the centrifugal impeller 6 is connected to the intake end of the secondary separator 8 through the exhaust connecting hole 301, and the oil mist flows through the centrifugal impeller 6 and the secondary separator 8 in sequence, and then reaches the oil mist exhaust port 13.

[0076] Specifically, refer to Figure 2 , Figure 8As shown, specifically, a mounting cavity for mounting the secondary separator 8 is provided inside the gearbox housing 3; the mounting cavity is provided in parallel with the mounting cavity for the input shaft 1, and correspondingly, the secondary separator 8 is provided in parallel with the axis of the centrifugal impeller 6. The two mounting cavities are connected through an exhaust connection hole 301, and specifically, the exhaust connection hole 301 is perpendicular to the above two mounting cavities, so that the intake and exhaust are smoother and the efficiency is increased.

[0077] For the installation method of the secondary separator 8, refer to Figure 2 , Figure 7 As shown, it also includes a gland 10 for confining the secondary separator 8 in the gearbox housing 3, the gland 10 includes a coaxially arranged gland top and a gland bottom; the gland top is fixedly connected to the gland bottom; the gland bottom is a hollow cylinder; the diameter of the gland top is larger than the diameter of the gland bottom, and the top of the gland 10 is provided with two shell connecting holes 102 symmetrically arranged along the circumferential direction. The fasteners pass through the shell connecting holes 102 to fix the gland 10 on the outer surface of the gearbox housing 3, and the end of the gland bottom away from the top contacts with the secondary separator 8, thereby confining the secondary separator 8 in the gearbox housing 3, and the secondary separator 8 can be removed by removing the gland 10. Specifically, a gland regulating port 101 corresponding to the exhaust connection hole 301 is provided on one side of the gland bottom, the gland regulating port 101 is connected with the inner wall of the gland bottom, the end of the gland bottom close to the gland top is a blind end, the gas enters the gland bottom through the gland regulating port 101, and the other end of the gland bottom away from the gland top is the exhaust end; the gas flows out from the exhaust connection hole 301, where the gas flow direction turns 90 degrees, and then enters the secondary separator 8. More specifically, the outer diameter of the gland bottom matches the inner diameter of the secondary separator 8 installation cavity, so that the gland top can better seal the installation cavity of the secondary separator 8.

[0078] In order to further improve the integration of the gearbox, the air inlet diameter of the gland regulating port 101 can be adjusted, and the oil mist passes through the centrifugal impeller 6, the gland regulating port 101, and the secondary separator 8 in sequence. Specifically, the gland regulating port 101 has the same diameter as the connecting exhaust hole 301. By adjusting the installation angle of the gland 10 along the circumferential direction, the gland regulating port 101 and the connecting exhaust hole 301 are staggered at a certain angle, thereby reducing the exhaust volume of the centrifugal impeller 6. When the air intake of the centrifugal impeller 6 remains unchanged and the exhaust volume is slightly reduced, the gearbox can be placed in a slightly negative pressure state. At the same time, the relative area of ​​the gland regulating port 101 is reduced, which will speed up the flow rate of the gas passing through here. The faster the flow rate, the better the separation effect will be when passing through the subsequent secondary separator 8, so that the oil mist separation is more thorough.

[0079] Regarding the way to adjust the air inlet diameter of the gland adjustment port 101, specifically, the shell connection hole 102 is a waist-shaped hole. By designing the shell connection hole 102 as a waist-shaped hole, the installation position of the fastener in the shell connection hole 102 can be adjusted along its arc direction, that is, the installation position of the shell connection hole 102 relative to the gearbox shell 3 can be adjusted along the circumferential direction. By adjusting the installation position of the shell connection hole 102 along the circumferential direction, the gland adjustment port 101 can be rotated slightly along the circumferential direction, driving the gland adjustment port 101 and the central axis of the connecting exhaust hole 301 to be staggered at a small angle, and the staggered angle is preferably 3-6°, thereby achieving the adjustment of the area facing the gland adjustment port 101 and the connecting exhaust hole 301, and then controlling the slight difference between the intake and exhaust volume of the gearbox.

[0080] After passing through the primary separator 7 and the centrifugal impeller 6, when it reaches the secondary separator 8, most of the oil mist particles in the oil mist have been removed, and only a very small part of the oil mist particles escape with the gas. The gas containing a small amount of oil mist is separated again by the secondary separator 8, which reduces the workload of the secondary separator 8 and thus prolongs the service life of the secondary separator 8. In order to further improve the efficiency of oil mist separation, the secondary separator 8 is a precision oil separation core. Under the action of the secondary separator 8, the oil mist and the gas are completely separated, and the clean gas is discharged through the oil mist exhaust port 13, and the clean gas flows in the internal exhaust pipe.

[0081] In order to realize the recycling of the oil mist separated by the secondary separator 8, a second connecting oil groove 303 is opened on the inner wall of the gear box housing 3. The second connecting oil groove 303 is located directly below the secondary separator 8 and is connected to the oil collecting groove of the gear box air inlet 12. The lubricating oil separated by the secondary separator 8 falls under the action of gravity and is collected in the second connecting oil groove 303, and finally flows into the inner cavity of the gear box, thereby realizing the recycling of the lubricating oil in the gear box.

[0082] The present invention also provides an integrated dry oil-free screw main unit comprising the gear box described in any of the above embodiments, Fig. 9 As shown, the main engine also includes a high-pressure head 4 and a low-pressure head 5, and the oil mist exhaust port 13 of the gear box blows toward the gear shaft in the high-pressure head 4 and the gear shaft in the low-pressure head 5 respectively. Fig. 9 In the flow trajectory indicated by f, the gas is divided into at least two branches after flowing out through the oil mist exhaust port 13, wherein the first branch 401 blows toward the gear shaft of the high-pressure head 4, and the second branch 501 blows toward the gear shaft in the low-pressure head 5.

[0083] During the operation of the traditional dry screw compressor main engine, the gears inside the gear box will form a large amount of oil mist and generate positive pressure due to the high-speed extrusion of the lubricating oil film and the splashing of high-speed centrifugal impact. The oil mist with positive pressure is easy to leak into the screw compression chamber through the sealing structure at the gear shaft of the low-pressure head 4 and the high-pressure head 5. By blowing clean air to the gear shaft of the low-pressure head 4 and the high-pressure head 5, not only can the oil mist on the gear shaft be blown away to prevent the oil mist from gathering here, but also prevent the local oil mist from being unable to participate in the oil mist separation and promote the circulation of the oil mist; it can also further prevent the oil mist from entering the head from here and polluting the compressed air.

[0084] The present invention and its embodiments are described schematically above, and the description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by it and designs a structural method and an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, they shall all fall within the protection scope of the present invention.

Claims

1. An integrated dry oil-free screw main engine gearbox, characterized in that: The gearbox comprises a gearbox housing (3) and an input shaft (1); a gear transmission group is installed inside the gearbox housing (3); one end of the input shaft (1) is fixedly connected to the output end of a driving mechanism, and the other end thereof extends into the gearbox housing (3) and drives the screw rotors in the high-pressure head and the low-pressure head to move through the gear transmission group; a support bearing (11), a primary separator (7) and a centrifugal impeller (6) are all installed inside the gearbox housing (3) and are sequentially mounted on the outside of the input shaft (1) along the flow direction of the oil mist channel, wherein the centrifugal impeller (6) is fixedly connected to the input shaft (1).

2. The integrated dry oil-free screw main engine gearbox according to claim 1, characterized in that: The primary separator (7) comprises a separator outer ring (704) and a separator inner ring (703) which are coaxially arranged; the input shaft (1) is sleeved inside the separator inner ring (703) and there is a gap between the input shaft (1) and the separator inner ring (703); the separator outer ring (704) and the separator inner ring (703) are fixedly connected via a plurality of baffles (701) which are arranged in parallel and spaced apart; a baffle channel is formed between adjacent baffles (701); a first oil collecting groove (702) which is connected to the baffle channel is provided in the separator outer ring (704); the first oil collecting groove (702) is connected to the oil collecting groove of the gear box air inlet (12).

3. The integrated dry oil-free screw main engine gearbox according to claim 2, characterized in that: The baffle plates (701) each comprise a baffle main plate (7011) extending in the axial direction of the input shaft (1), baffle baffles (7012) arranged at staggered intervals are provided on both sides of the baffle main plate (7011), and the inner side surface thereof and the outer side surface of the baffle baffle (7012) form a V-shaped groove, and the opening of the V-shaped groove is 40 to 60 degrees; And / or the first oil collecting groove (702) includes a radial oil collecting groove (7021) and a plurality of axial oil collecting grooves (7022) perpendicular to the radial oil collecting groove (7021) and distributed in parallel and at intervals, the axial oil collecting groove (7022) extending along the axial direction of the input shaft (1) and penetrating the separator outer ring (704), and being connected to the deflection channel, and the radial oil collecting groove (7021) extending along the circumferential direction of the separator outer ring (704) and being connected to the plurality of axial oil collecting grooves (7022).

4. The integrated dry oil-free screw main engine gearbox according to any one of claims 1 to 3, characterized in that: One end of the primary separator (7) is in contact with the outer ring of the support bearing (11), and the other ends of the primary separator (7) and the support bearing (11) are axially fixed by a retaining ring; And / or the outer side of the primary separator (7) is also provided with at least two limit blocks (705) spaced apart along its circumferential direction, and the limit blocks (705) are installed in the oil collecting tank of the gear box air inlet (12).

5. The integrated dry oil-free screw main engine gearbox according to any one of claims 1 to 3, characterized in that: The centrifugal impeller (6) comprises an impeller inner ring (603) and an upper ring piece (601) which are coaxially arranged; the input shaft (1) is sleeved inside the impeller inner ring (603) and fixedly connected to the impeller inner ring (603); one end of the impeller inner ring (603) extends radially to form a lower ring piece (604); the upper ring piece (601) is located at the other end of the impeller inner ring (603), and an annular impeller air inlet groove is formed between the two; and a plurality of impeller blades (602) distributed along an annular interval are provided between the lower ring piece (604) and the upper ring piece (601).

6. The integrated dry oil-free screw main engine gearbox according to claim 5, characterized in that: A secondary separator (8) is also provided inside the gear box on one side of the input shaft (1), and the exhaust end of the centrifugal impeller (6) is connected to the intake end of the secondary separator (8) through an exhaust connection hole (301).

7. The integrated dry oil-free screw main engine gearbox according to claim 6, characterized in that: It also includes a gland (10) for confining the secondary separator (8) inside the gearbox housing (3), and a gland adjustment port (101) corresponding to the exhaust connection hole (301) is provided on one side of the bottom of the gland, wherein the diameter of the gland adjustment port (101) facing the exhaust connection hole (301) can be adjusted.

8. The integrated dry oil-free screw main engine gearbox according to claim 7, characterized in that: The top of the gland is provided with two shell connecting holes (102) symmetrically arranged along the circumferential direction, and the shell connecting holes (102) are waist-shaped holes.

9. The integrated dry oil-free screw main engine gearbox according to claim 5, characterized in that: The oil collecting tank of the secondary separator (8) is in communication with the oil collecting tank of the air inlet of the gear box; And / or the secondary separator (8) is a precision oil separator core.

10. An integrated dry oil-free screw main unit, characterized in that: It comprises a high-pressure head (4), a low-pressure head (5) and a gear box as claimed in any one of claims 1 to 9.

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