Active adjusting device and method for axial force of screw compressor

Abstract

The invention belongs to the technical field of screw compressors, and discloses a screw compressor axial force active adjusting device and a method thereof.The screw compressor axial force active adjusting device comprises a screw male rotor, a balance force set is arranged on one end face of the screw male rotor, and a gap is formed between the screw male rotor and the balance force set; the end, close to the balance force set, of the screw male rotor is sleeved with an angular contact bearing set, the end, close to the angular contact bearing set, of the screw male rotor is sleeved with an axial thrust disc, and the axial thrust disc abuts against the angular contact bearing set. The device is simple in overall structure, axial force can be adjusted through magnetic force, the magnitude of a magnetic field is changed by actively controlling the magnitude of current, and the magnitude of the axial force is changed; meanwhile, the mechanical adjusting structure is not in direct contact with the male rotor, sealing difficulty of rotor machining is reduced, and the using effect is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of screw compressors, and in particular, relates to a device and method for actively adjusting the axial force of a screw compressor. Background Art

[0002] In the field of screw compressors, the regulation of axial force has always been one of the key technical issues. During the operation of the screw compressor, a certain axial force will be generated due to the compression and exhaust process of the gas. If this axial force is too large or the direction is incorrect, it will cause serious wear on the male rotor and other components of the compressor, and even cause the compressor to fail and shut down.

[0003] During the gas compression process of the screw compressor, the rotor is subjected to a large axial force. The axial force is usually borne by the angular contact bearing, resulting in excessive force. The existing solution is usually to design a balancing piston at one end to reduce the axial load through the piston thrust. By adding an axial force force measuring element, the balancing piston oil pressure is actively adjusted to balance the axial force. In actual engineering, not only is it necessary to design an additional oil pump and hydraulic pipeline, but improper design of the balancing piston may also lead to problems such as excessive oil pressure and over-balancing.

[0004] A Chinese patent with application number CN2023115318482 discloses an axial force adjustment device for a screw compressor, which is used to adjust the axial force of the male rotor of the screw compressor. The axial force adjustment device for the screw compressor includes a first magnet and an adjusting piston. The first magnet is arranged at one end of the male rotor of the screw compressor. The adjusting piston includes a piston cylinder, an elastic member, a piston body, a piston pressure inlet and a piston pressure outlet. The piston cylinder includes a accommodating chamber, and the piston pressure inlet and the piston pressure outlet are relatively arranged on the piston cylinder. The elastic member and the piston body are sequentially arranged in the accommodating chamber of the piston cylinder, and the piston body includes a second magnet. The male rotor is arranged near the piston pressure outlet. The present application balances the axial force exerted on the male rotor by the magnetic repulsion of the first magnet and the piston body. The adjusting piston does not directly contact the male rotor, has a simple structure, reduces the difficulty of processing and sealing, and adjusts the magnetic repulsion by means of a piston, so that the adjustment is stable and does not change suddenly. However, in this patent, the balancing force is generated by setting the first magnet and the second magnet to repel each other, and the magnets are easily demagnetized during long-term use, which affects the generated balancing force. Furthermore, the size of the balancing force is adjusted by moving the second magnet, which has a complex structure and increases the production and debugging costs. Summary of the invention

[0005] The main technical problem to be solved by the present invention is to provide an active axial force adjustment device for a screw compressor and a method thereof, which can adjust the axial force by magnetic force, and change the size of the axial force by actively controlling the current size and thus changing the size of the magnetic field; at the same time, the mechanical adjustment structure does not directly contact the positive rotor, thereby reducing the sealing difficulty of the rotor processing.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: An active axial force adjustment device for a screw compressor and a method thereof, comprising a screw male rotor, a balancing force group is arranged at one end surface of the screw male rotor, a gap is arranged between the screw male rotor and the balancing force group, an angular contact bearing group is sleeved at one end of the screw male rotor close to the balancing force group, an axial thrust plate is sleeved at one end of the screw male rotor close to the angular contact bearing group, and the axial thrust plate is top-connected with the angular contact bearing group; The balancing force group comprises a support seat, on which an axial thrust magnetic bearing is adjustably mounted near the axial thrust disc, and a coil is wound around the axial thrust magnetic bearing near the axial thrust disc.

[0007] The following is a further optimization of the above technical solution by the present invention: The screw male rotor comprises a rotor body directly connected to the motor, a rotor shaft is vertically arranged on one end surface of the rotor body close to the balancing force group, and the outer diameter of the rotor shaft is smaller than the diameter of the rotor body.

[0008] Further optimization: the angular contact bearing group is sleeved on the outer surface of the rotor shaft, and one end surface of the angular contact bearing group is in contact with the end surface of the rotor body.

[0009] Further optimization: the angular contact bearing group includes a plurality of angular contact bearings sleeved on the outer surface of the rotor shaft.

[0010] Further optimization: the axial thrust disc comprises a disc sleeve sleeved on the outer circumferential surface of the rotor shaft, and the disc sleeve and the outer circumferential surface of the rotor shaft are interference fit; A force-bearing plate is fixedly mounted on one end surface of the disc sleeve away from the angular contact bearing, and the force-bearing plate is sleeved on the outer circumferential surface of the rotor shaft by interference fit.

[0011] Further optimization: a placement groove in the shape of a ring is provided on the end surface of the support seat close to the axial thrust disc and close to the edge, a vertical adjustment ring is movably placed in the placement groove, a plurality of avoidance holes are provided in a ring array on the surface, and threaded holes are provided on the surface of the placement groove at positions corresponding to each avoidance hole; A second pin hole is provided at a middle position on the end surface of the support seat close to the axial thrust disc.

[0012] Further optimization: the axial thrust magnetic bearing comprises a flat plate which is adjustably mounted on the end surface of the support seat, through holes are provided at positions corresponding to the threaded holes on the flat plate, and a first pin hole is provided at a position corresponding to the second pin hole on the end surface of the flat plate close to the support seat; The through hole and the corresponding avoidance hole and threaded hole of the verticality adjustment ring are provided with fixing bolts; The same pin shaft is inserted into the first pin hole and the second pin hole.

[0013] Further optimization: a retaining ring is vertically arranged at the upper edge of one end surface of the plate away from the support seat, and a magnetic pole is vertically arranged at the position close to the retaining ring on one end surface of the plate away from the support seat; A wire groove is provided between the retaining ring and the magnetic pole; The coil is wound on the outer circumferential surface of the magnetic pole close to the retaining ring, and the magnetic pole is located in the wire slot at the same time.

[0014] The present invention also provides a method for actively adjusting the axial force of a screw compressor, based on the above-mentioned active axial force adjustment device for a screw compressor, comprising the following steps: S1: Connect one end of the screw male rotor to the motor of the screw machine, and install the other end to the angular contact bearing set, then sleeve the axial thrust plate on the other end of the screw male rotor and make it contact with one end face of the angular contact bearing set; S2: Fix the support seat on the compressor housing, put the verticality adjustment ring into the placement groove, position and install the axial thrust magnetic bearing on the support seat through the pin shaft, and thread the fixing bolts through the corresponding through holes and avoidance holes in sequence, and then thread them on the threaded holes and lock them; S3: Wrap the coil around the outer surface of the magnetic pole and put it into the wire slot. Both ends of the coil are electrically connected to the control system of the screw compressor to ensure that current can flow into the coil during operation. S4: During operation, the screw male rotor rotates to generate a rightward axial force F. At the same time, the angular contact bearing generates a thrust f2 in the opposite direction to the axial force F during the rotation process, thereby offsetting part of the axial force F. S5: Current is passed through the coil, and a magnetic field is generated under the joint action of the magnetic poles to form an attractive force f1 to the left. The attractive force f1 acts on the axial thrust disk, attracting the axial thrust disk to move to the left. The attractive force f1 offsets the remaining axial force F, and the adjustment is completed.

[0015] The present invention adopts the above technical solution and has the following beneficial effects: 1. The present invention adopts the above technical solution, and sets a balancing force group that does not contact the screw male rotor to adjust and offset the axial force generated by the rotation of the screw male rotor. The structure is simple, easy to adjust and install, and the mechanical wear caused by contact use is reduced, which can extend the service life; 2. By winding a coil on the outer surface of the magnetic pole and passing current through the coil, a magnetic field is generated under the joint action of the magnetic poles, that is, an attractive force opposite to the axial force is generated. The size of the attractive force can be adjusted by changing the size of the current, thereby balancing the axial force and reducing the mechanical wear of the angular contact bearing caused by excessive axial force; 3. Furthermore, when the number of angular contact bearings is reduced, the remaining axial force can be balanced by simply increasing the coil current to increase the attractive force generated, thereby shortening the overall length of the screw male rotor and making the rotation more stable; 4. The principle of adjusting the balancing force by electromagnetism of the present invention can also be used on a variety of rotor structures, which is easier to realize universalization and has more obvious beneficial effects.

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a cross-sectional view of the overall structure in an embodiment of the present invention; Figure 2 Schematic diagram of the installation of coils in an axial thrust magnetic bearing according to an embodiment of the present invention; Figure 3 It is a force diagram of the overall structure in an embodiment of the present invention.

[0018] In the figure: 1. screw male rotor; 11. rotor body; 12. rotor shaft; 2. angular contact bearing group; 21. angular contact bearing; 3. axial thrust plate; 31. disk sleeve; 32. force plate; 4. balancing force group; 41. axial thrust magnetic bearing; 410. flat plate; 411. magnetic pole; 412. wire groove; 413. retaining ring; 414. through hole; 415. first pin hole; 42. coil; 43. pin shaft; 44. fixing bolt; 45. support seat; 450. placement groove; 451. threaded hole; 452. second pin hole; 46. verticality adjustment ring; 5. gap. DETAILED DESCRIPTION

[0019] like Figure 1-3 As shown: an active axial force adjustment device for a screw compressor comprises a screw male rotor 1, a balancing force group 4 is arranged at one end surface of the screw male rotor 1, a gap 5 is arranged between the screw male rotor 1 and the balancing force group 4, an angular contact bearing group 2 is sleeved at one end of the screw male rotor 1 close to the balancing force group 4, an axial thrust plate 3 is sleeved at one end of the screw male rotor 1 close to the angular contact bearing group 2, and the axial thrust plate 3 is in top contact with the angular contact bearing group 2; The balancing force group 4 comprises a support seat 45 , on which an axial thrust magnetic bearing 41 is adjustably mounted near the axial thrust disc 3 , and a coil 42 is wound around the axial thrust magnetic bearing 41 near the axial thrust disc 3 .

[0020] In this embodiment, the other end of the screw male rotor 1 is directly connected to the motor power output end of the screw air compressor, and the motor drives the screw male rotor 1 to rotate, thereby generating an axial force.

[0021] like Figure 3As shown, the screw male rotor 1 rotates to generate an axial force F to the right.

[0022] The screw male rotor 1 includes a rotor body 11 directly connected to the motor, and a rotor shaft 12 is vertically arranged on an end surface of the rotor body 11 close to the balancing force group 4 .

[0023] The outer diameter of the rotor shaft 12 is smaller than the diameter of the rotor body 11 .

[0024] The angular contact bearing assembly 2 is sleeved on the outer surface of the rotor shaft 12 , and one end surface of the angular contact bearing assembly 2 is in contact with the end surface of the rotor body 11 .

[0025] The angular contact bearing group 2 includes a plurality of angular contact bearings 21 sleeved on the outer surface of the rotor shaft 12, and the outer circumferential surfaces of the plurality of angular contact bearings 21 are fixedly mounted on the housing of the screw air compressor at the same time.

[0026] The angular contact bearing 21 can support the screw male rotor 1, and when the screw male rotor 1 rotates, it provides a radial force and a thrust f2 in the opposite direction to the axial force F, so as to balance the axial force generated by the rotation of part of the screw male rotor 1. The greater the axial force, the more angular contact bearings 21 are required, thereby improving the rotation stability of the screw male rotor 1.

[0027] like Figure 1 As shown, the axial thrust disk 3 includes a disk sleeve 31 sleeved on the outer circumferential surface of the rotor shaft 12 , and the disk sleeve 31 is interference fit with the outer circumferential surface of the rotor shaft 12 .

[0028] One end of the disc sleeve 31 contacts the adjacent angular contact bearing 21 .

[0029] A force-bearing plate 32 is fixedly mounted on one end surface of the disk sleeve 31 away from the angular contact bearing 21 , and the force-bearing plate 32 is sleeved on the outer circumferential surface of the rotor shaft 12 by interference fit.

[0030] In this embodiment, the axial thrust disk 3 is made of magnetic material.

[0031] The support seat 45 is fixedly installed at the end position of the shell of the screw air compressor.

[0032] An annular placement groove 450 is provided on the end surface of the support seat 45 close to the axial thrust plate 3 and close to the edge.

[0033] A verticality adjustment ring 46 is movably placed in the placement groove 450. In this embodiment, the verticality adjustment ring 46 is made of soft metal material and can fine-tune the position of the axial thrust magnetic bearing 41 to ensure the parallelism between the axial thrust magnetic bearing 41 and the axial thrust disk 3, that is, to ensure that the axial clearance between the axial thrust magnetic bearing 41 and the axial thrust disk 3 is consistent.

[0034] The surface of the verticality adjustment ring 46 has a plurality of avoidance holes in an annular array.

[0035] The surface of the placement groove 450 is provided with threaded holes 451 at positions corresponding to each avoidance hole.

[0036] A second pin hole 452 is formed at a middle position on the end surface of the support seat 45 close to the axial thrust plate 3 .

[0037] The axial thrust magnetic bearing 41 includes a flat plate 410 adjustably mounted on an end surface close to a support seat 45 .

[0038] Through holes 414 are formed on the plate 410 at positions corresponding to the threaded holes 451 .

[0039] A first pin hole 415 is formed on the end surface of the flat plate 410 close to the support seat 45 and at a position corresponding to the second pin hole 452 .

[0040] The through hole 414 and the corresponding avoidance hole and threaded hole 451 are provided with fixing bolts 44, that is, the fixing bolts 44 pass through the through hole 414 and the avoidance hole and are threadedly connected in the threaded hole 451. Such a design can fix the axial thrust magnetic bearing 41 on the support seat 45.

[0041] The same pin shaft 43 is inserted into the first pin hole 415 and the second pin hole 452. The pin shaft 43 is used to position the axial thrust magnetic bearing 41 and the support seat 45 when installing, so that the axial thrust magnetic bearing 41 remains concentric with the axial thrust disk 3 after installation.

[0042] A retaining ring 413 is vertically arranged at the upper edge of one end surface of the flat plate 410 away from the supporting seat 45 .

[0043] A magnetic pole 411 is vertically arranged on an end surface of the flat plate 410 away from the support seat 45 and close to the retaining ring 413 .

[0044] A wire groove 412 is provided between the retaining ring 413 and the magnetic pole 411 .

[0045] The coil 42 is wound around the outer circumferential surface of the magnetic pole 411 close to the retaining ring 413 , and the magnetic pole 411 is located in the wire slot 412 .

[0046] A gap 5 is provided between the magnetic pole 411 and the force-bearing plate 32 , that is, the axial thrust magnetic bearing 41 is not in direct contact with the force-bearing plate 32 , thereby reducing the degree of abrasion and increasing the service life.

[0047] The present invention also provides a method for actively adjusting the axial force of a screw compressor, based on the above-mentioned active axial force adjustment device for a screw compressor, comprising the following steps: S1: Connect one end of the screw male rotor 1 to the motor, and install the other end to the angular contact bearing group 2 of the housing, then sleeve the axial thrust plate 3 on the other end of the screw male rotor 1 and make it contact with one end surface of the angular contact bearing group 2; S2: The support seat 45 is fixedly installed on the compressor housing, and then the vertical adjustment ring 46 is placed in the placement groove 450, and the axial thrust magnetic bearing 41 is positioned and installed on the support seat 45 through the pin shaft 43, and the fixing bolt 44 is sequentially passed through the corresponding through hole 414 and the avoidance hole, and then threadedly connected to the threaded hole 451 and locked; S3: Wrap the coil 42 around the outer surface of the magnetic pole 411 and put it into the wire slot 412. Both ends of the coil 42 are electrically connected to the control system of the screw compressor to ensure that current can flow into the coil 42 during operation. S4: During operation, the screw male rotor 1 rotates to generate a rightward axial force F. At the same time, the angular contact bearing 21 generates a thrust f2 in the opposite direction to the axial force F during the rotation process, thereby offsetting part of the axial force F. S5: Current is passed through the coil 42, and a magnetic field is generated under the joint action of the magnetic pole 411 to form an attractive force f1 to the left. The attractive force f1 acts on the axial thrust disk 3, attracting the axial thrust disk 3 to move to the left. The attractive force f1 offsets the remaining axial force F, and the adjustment is completed.

[0048] When in use, when the attraction force f1 offsets part of the axial force F, the axial load of the angular contact bearing 21 is reduced, that is, the bearing wear caused by the excessive axial force F is reduced.

[0049] When the number of angular contact bearings 21 is reduced, that is, the thrust f2 generated by the angular contact bearing group 2 is reduced, the attraction f1 generated can be increased simply by increasing the current of the coil 42, thereby shortening the overall length of the screw male rotor 1 and reducing the cost of use.

[0050] In addition to this embodiment, when the diameter of the screw male rotor 1 changes, thereby causing the generated axial force F to change, it is only necessary to change the current passed through the coil 42 to adjust the generated attraction force f1 to match the corresponding axial force F, which is simple to adjust and highly universal. Furthermore, the current flowing through the coil 42 is stable, that is, the generated magnetic field is stable, and the generated attraction f1 is stable, so that the entire device can be used stably, and the size of the balanced regulating force is stable and does not change suddenly, thereby improving the use effect.

[0051] At the same time, the active axial force adjustment device for the screw compressor can also be used for adjusting the balancing force of various rotor structures such as the female rotor, thereby increasing its wide application.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An active axial force adjustment device for a screw compressor, comprising a screw male rotor (1), characterized in that: A balancing force group (4) is provided at one end surface of the screw male rotor (1), a gap (5) is provided between the screw male rotor (1) and the balancing force group (4), an angular contact bearing group (2) is sleeved on one end of the screw male rotor (1) close to the balancing force group (4), an axial thrust plate (3) is sleeved on one end of the screw male rotor (1) close to the angular contact bearing group (2), and the axial thrust plate (3) is in top contact with the angular contact bearing group (2); The balancing force group (4) comprises a support seat (45), on which an axial thrust magnetic bearing (41) is adjustably mounted near the axial thrust disc (3), and a coil (42) is wound around the axial thrust magnetic bearing (41) at a position near the axial thrust disc (3).

2. The active axial force adjustment device for a screw compressor according to claim 1, characterized in that: The screw male rotor (1) comprises a rotor body (11) directly connected to the motor, a rotor shaft (12) being vertically arranged on an end surface of the rotor body (11) close to the balancing force group (4), and an outer diameter of the rotor shaft (12) being smaller than a diameter of the rotor body (11).

3. The active axial force adjustment device for a screw compressor according to claim 2, characterized in that: The angular contact bearing group (2) is sleeved on the outer surface of the rotor shaft (12), and one end surface of the angular contact bearing group (2) is in contact with the end surface of the rotor body (11).

4. The active axial force adjustment device for a screw compressor according to claim 3, characterized in that: The angular contact bearing group (2) comprises a plurality of angular contact bearings (21) sleeved on the outer surface of the rotor shaft (12).

5. The active axial force regulating device for a screw compressor according to claim 4, characterized in that: The axial thrust disc (3) comprises a disc sleeve (31) sleeved on the outer circumferential surface of the rotor shaft (12), the disc sleeve (31) and the outer circumferential surface of the rotor shaft (12) being in interference fit; A force-bearing plate (32) is fixedly mounted on one end surface of the disc sleeve (31) away from the angular contact bearing (21), and the force-bearing plate (32) is sleeved on the outer circumferential surface of the rotor shaft (12) with an interference fit.

6. The active axial force regulating device for a screw compressor according to claim 5, characterized in that: An annular placement groove (450) is provided on the end surface of the support seat (45) close to the axial thrust disc (3) and close to the edge thereof, a verticality adjustment ring (46) is movably placed in the placement groove (450), a plurality of avoidance holes are provided in an annular array on the surface of the verticality adjustment ring (46), and a threaded hole (451) is provided on the surface of the placement groove (450) at a position corresponding to each avoidance hole; A second pin hole (452) is provided at a middle position on the end surface of the support seat (45) close to the axial thrust disc (3).

7. The active axial force regulating device for a screw compressor according to claim 6, characterized in that: The axial thrust magnetic bearing (41) comprises a plate (410) which is adjustably mounted on an end surface close to the support seat (45), a through hole (414) is provided at a position on the plate (410) corresponding to the threaded hole (451), and a first pin hole (415) is provided at a position on the end surface of the plate (410) close to the support seat (45) and corresponding to the second pin hole (452); A fixing bolt (44) is disposed in the through hole (414), the corresponding avoidance hole of the verticality adjustment ring (46), and the threaded hole (451); The first pin hole (415) and the second pin hole (452) are plugged with the same pin shaft (43).

8. The active axial force regulating device for a screw compressor according to claim 7, characterized in that: A retaining ring (413) is vertically arranged at an upper edge position of an end surface of the flat plate (410) away from the support seat (45), and a magnetic pole (411) is vertically arranged at a position close to the retaining ring (413) on an end surface of the flat plate (410) away from the support seat (45); A wire groove (412) is provided between the retaining ring (413) and the magnetic pole (411); The coil (42) is wound on the outer circumferential surface of the magnetic pole (411) close to the retaining ring (413), and the magnetic pole (411) is simultaneously located in the wire groove (412).

9. A method for actively adjusting the axial force of a screw compressor, based on the device for actively adjusting the axial force of a screw compressor according to claim 8, characterized in that: The following steps are involved: S1: Connect one end of the screw male rotor (1) to the motor of the screw machine, and install the other end to the angular contact bearing assembly (2). Then, sleeve the axial thrust plate (3) on the other end of the screw male rotor (1) and make contact with one end surface of the angular contact bearing assembly (2). S2: The support seat (45) is fixedly mounted on the compressor housing, and then the verticality adjustment ring (46) is placed in the placement groove (450), and the axial thrust magnetic bearing (41) is positioned and mounted on the support seat (45) through the pin shaft (43), and the fixing bolt (44) is sequentially passed through the corresponding through hole (414) and the avoidance hole, and then threadedly connected to the threaded hole (451) and locked; S3: Winding the coil (42) around the outer surface of the magnetic pole (411) and placing it in the wire slot (412), and electrically connecting the two ends of the coil (42) to the control system of the screw compressor to ensure that current can flow into the coil (42) during operation; S4: During operation, the screw male rotor (1) rotates to generate a rightward axial force F. At the same time, the angular contact bearing (21) generates a thrust f2 in the opposite direction to the axial force F during the rotation process, thereby offsetting a part of the axial force F. S5: Current is passed through the coil (42), and a magnetic field is generated under the joint action of the magnetic poles (411) to form an attractive force f1 to the left. The attractive force f1 acts on the axial thrust disk (3), attracting the axial thrust disk (3) to move to the left. The attractive force f1 offsets the remaining axial force F, and the adjustment is completed.

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