A divergent split-tooth stepped magnetohydrodynamic rotary sealing device

Abstract

The object of the present invention is to provide a divergent split-tooth stepped magneto-fluid rotary sealing device, which comprises a shaft, a housing, a first pole shoe ring, a second pole shoe ring, a third pole shoe ring, a fourth pole shoe ring, a first sleeve, a second sleeve, a third sleeve, a first permanent magnet ring, a second permanent magnet ring, and a third permanent magnet ring. The sealing device of the present invention can not only improve the magnetic flux concentration effect so as to improve the pressure resistance of the magneto-fluid seal, but also effectively prevent the failure of the magneto-fluid seal caused by the action of centrifugal force, reduce the loss of magneto-fluid, and improve the reliability and service life of the seal.

Description

Technical Field

[0001] The present invention belongs to the field of mechanical engineering seals, and particularly relates to a divergent split-tooth stepped magnetic fluid rotary seal device. Background Art

[0002] Magnetic fluid, also known as ferrofluid or magnetic liquid, is a new type of functional material. In recent years, magnetic fluid has developed rapidly in the field of seals. Magnetic fluid sealing uses a permanent magnet to generate a magnetic field force in the sealing gap to firmly fix the magnetic fluid in the sealing gap, resisting the pressure difference on both sides, thereby achieving the sealing effect. Moreover, since there are strict requirements for sealing in many industrial applications, especially the requirement of zero leakage, which cannot be achieved by general traditional mechanical seals, magnetic fluid sealing can well solve the above problems. Magnetic fluid sealing technology has the advantages of zero leakage rate, no solid friction, long life, high reliability, etc. compared with traditional sealing technologies, and has been widely applied in various industries.

[0003] The sleeve stepped seal is to assemble the sleeve in a stepped manner, and process threads in the inner hole of the sleeve to form a threaded connection with the shaft, thereby forming a structure similar to a stepped shaft. That is, a new type of sealing method is formed by keeping the axial clearance between each pole shoe and its corresponding sleeve unchanged. Therefore, when saturated magnetic fluid is injected, it not only improves the pressure resistance of the original magnetic fluid seal, but also changes the leakage direction when the sealed medium leaks, increasing the length of the leakage path, thereby improving the pressure resistance of the seal.

[0004] For the seal devices described in Comparative Document 1 (patent with publication number CN10311B) and Comparative Document 2 (patent with publication number CN207740466U), although Document 1 solves the problem of rotary seal leakage in large gaps to a certain extent, due to the limitation of shaft processing conditions, the shaft shoulder height cannot be greater than 10% of the shaft diameter during design, and it cannot play a good pressure resistance effect in the axial clearance. The structure of Document 2 is a multi-stage disc magnetic fluid seal device, which can solve the problem of low pressure resistance performance of magnetic fluid seal devices to a certain extent. However, when the radial clearance is a small gap, the pressure resistance effect of the axial pole teeth is significantly reduced, making it difficult to successfully apply this sealing technology in fields such as high-speed and heavy-duty. Therefore, there is an urgent need for a structure with simple assembly, which can be used under working conditions with large radial runout, sufficient pressure-resistant sealing ability, a single number of permanent magnets, and obvious magnetic focusing effect. Summary of the Invention

[0005] The purpose of the present invention is to provide a divergent split-tooth stepped magnetic fluid rotary seal device, which can not only improve the magnetic focusing effect to enhance the pressure resistance of magnetic fluid seals, but also effectively prevent the failure of magnetic fluid seals caused by the action of centrifugal force, reduce the loss of magnetic fluid, and improve the reliability and life of the seal.

[0006] The technical solution of the present invention is as follows:

[0007] The divergent split-tooth stepped magneto - fluid rotary sealing device includes a shaft, a housing, a first pole shoe ring, a second pole shoe ring, a third pole shoe ring, a fourth pole shoe ring, a first sleeve, a second sleeve, a third sleeve, a first permanent magnet ring, a second permanent magnet ring, and a third permanent magnet ring;

[0008] The first pole shoe ring, the second pole shoe ring, the third pole shoe ring, and the fourth pole shoe ring are sequentially arranged at intervals on the inner wall of the housing from left to right. The first pole shoe ring, the second pole shoe ring, the third pole shoe ring, and the fourth pole shoe ring extend radially towards the outer circular surface of the shaft, leaving a gap between them and the outer circular surface of the shaft;

[0009] The first permanent magnet ring, the second permanent magnet ring, and the third permanent magnet ring are respectively arranged on the inner wall of the housing; the first permanent magnet ring is located between the first pole shoe ring and the second pole shoe ring, and both ends of the first permanent magnet ring are in contact with the first pole shoe ring and the second pole shoe ring respectively; the second permanent magnet ring is located between the second pole shoe ring and the third pole shoe ring, and both ends of the second permanent magnet ring are in contact with the second pole shoe ring and the third pole shoe ring respectively; the third permanent magnet ring is located between the third pole shoe ring and the fourth pole shoe ring, and both ends of the third permanent magnet ring are in contact with the third pole shoe ring and the fourth pole shoe ring respectively;

[0010] The first sleeve, the second sleeve, and the third sleeve are sequentially arranged at intervals on the outer circular surface of the shaft by means of thread fitting from left to right. The outer circular surfaces of the first sleeve, the second sleeve, and the third sleeve respectively correspond to the inner circular surfaces of the first permanent magnet ring, the second permanent magnet ring, and the third permanent magnet ring; the radial heights of the first sleeve, the second sleeve, and the third sleeve increase sequentially;

[0011] On the right end face of the first pole shoe ring, a concave surface Ⅰ is provided on the side close to the shaft; on the left end face of the second pole shoe ring, a concave surface Ⅱ is provided on the side close to the shaft;

[0012] The concave surface Ⅰ corresponds to the left end face of the first sleeve. On the concave surface Ⅰ, multiple groups of pole teeth a and pole teeth b are alternately arranged at intervals along its radial direction; on the left end face of the first sleeve, multiple groups of pole teeth c and pole teeth d are alternately arranged at intervals along the radial direction. The pole teeth a and pole teeth b extend axially to the right, and the pole teeth c and pole teeth d extend axially to the left; the right end face of the pole tooth a corresponds to the left end face of the pole tooth c, leaving a gap therebetween, and magnetic fluid is filled in this gap; the right end face of the pole tooth b corresponds to the left end face of the pole tooth d, leaving a gap therebetween, and magnetic fluid is filled in this gap;

[0013] The concave surface II corresponds to the right end face of the first sleeve. Multiple sets of pole teeth e and pole teeth f are alternately arranged at intervals along the radial direction of the concave surface II. Multiple sets of pole teeth g and pole teeth h are alternately arranged at intervals along the radial direction of the left end face of the first sleeve. The pole teeth e and pole teeth f extend leftward along the axial direction, and the pole teeth g and pole teeth h extend rightward along the axial direction. The left end face of the pole tooth e corresponds to the right end face of the pole tooth g, with a gap therebetween, and the gap is filled with magnetic fluid. The left end face of the pole tooth f corresponds to the right end face of the pole tooth h, with a gap therebetween, and the gap is filled with magnetic fluid.

[0014] On the right end face of the second pole shoe ring, there is a concave surface III on the side close to the axis. On the left end face of the third pole shoe ring, there is a concave surface IV on the side close to the axis.

[0015] The concave surface III corresponds to the left end face of the second sleeve. Multiple sets of pole teeth i and pole teeth j are alternately arranged at intervals along the radial direction of the concave surface III. Multiple sets of pole teeth k and pole teeth l are alternately arranged at intervals along the radial direction of the left end face of the second sleeve. The pole teeth i and pole teeth j extend rightward along the axial direction, and the pole teeth k and pole teeth l extend leftward along the axial direction. The right end face of the pole tooth i corresponds to the left end face of the pole tooth j, with a gap therebetween, and the gap is filled with magnetic fluid. The right end face of the pole tooth k corresponds to the left end face of the pole tooth l, with a gap therebetween, and the gap is filled with magnetic fluid.

[0016] The concave surface IV corresponds to the right end face of the second sleeve. Multiple sets of pole teeth m and pole teeth n are alternately arranged at intervals along the radial direction of the concave surface IV. Multiple sets of pole teeth o and pole teeth p are alternately arranged at intervals along the radial direction of the left end face of the second sleeve. The pole teeth m and pole teeth n extend leftward along the axial direction, and the pole teeth o and pole teeth p extend rightward along the axial direction. The left end face of the pole tooth m corresponds to the right end face of the pole tooth o, with a gap therebetween, and the gap is filled with magnetic fluid. The left end face of the pole tooth n corresponds to the right end face of the pole tooth p, with a gap therebetween, and the gap is filled with magnetic fluid.

[0017] On the right end face of the third pole shoe ring, there is a concave surface V on the side close to the axis. On the left end face of the fourth pole shoe ring, there is a concave surface VI on the side close to the axis.

[0018] The concave surface V corresponds to the left end surface of the third sleeve, and multiple groups of pole teeth q and pole teeth r are arranged alternately along the radial direction on the concave surface V; multiple groups of pole teeth s and pole teeth t are arranged alternately along the radial direction on the left end surface of the third sleeve, and the pole teeth q and pole teeth r extend axially to the right, and the pole teeth s and pole teeth t extend axially to the left; the right end surface of the pole tooth q corresponds to the left end surface of the pole tooth s, and a gap is left between them, and the gap is filled with magnetic fluid; the right end surface of the pole tooth r corresponds to the left end surface of the pole tooth t, and a gap is left between them, and the gap is filled with magnetic fluid;

[0019] The concave surface VI corresponds to the right end surface of the third sleeve, and a plurality of groups of pole teeth u and pole teeth v are arranged alternately along the radial direction on the concave surface VI; a plurality of groups of pole teeth w and pole teeth x are arranged alternately along the radial direction on the left end surface of the third sleeve, and the pole teeth u and pole teeth v extend axially to the left, and the pole teeth w and pole teeth x extend axially to the right; the left end surface of the pole tooth u corresponds to the right end surface of the pole tooth w, and a gap is left between them, and the gap is filled with magnetic fluid; the left end surface of the pole tooth v corresponds to the right end surface of the pole tooth x, and a gap is left between them, and the gap is filled with magnetic fluid.

[0020] The magnetic fluid between the right end face of the pole tooth a and the left end face of the pole tooth c is distributed alternately with the magnetic fluid between the right end face of the pole tooth b and the left end face of the pole tooth d in the radial direction; the magnetic fluid between the left end face of the pole tooth e and the right end face of the pole tooth g is distributed alternately with the magnetic fluid between the left end face of the pole tooth f and the right end face of the pole tooth h in the radial direction;

[0021] The magnetic fluid between the right end face of the pole tooth i and the left end face of the pole tooth j is distributed alternately with the magnetic fluid between the right end face of the pole tooth k and the left end face of the pole tooth l in the radial direction; the magnetic fluid between the left end face of the pole tooth m and the pole tooth o is distributed alternately with the magnetic fluid between the left end face of the pole tooth n and the right end face of the pole tooth p in the radial direction;

[0022] The magnetic fluid between the right end face of pole tooth q and the left end face of pole tooth s is distributed alternately with the magnetic fluid between the right end face of pole tooth r and the left end face of pole tooth t in the radial direction; the magnetic fluid between the left end face of pole tooth u and the right end face of pole tooth w is distributed alternately with the magnetic fluid between the left end face of pole tooth v and the right end face of pole tooth x in the radial direction.

[0023] The polar teeth a are provided with 1-5, and the polar teeth c are provided corresponding to the polar teeth a15; the polar teeth b are provided with 1-5, and the polar teeth d are provided corresponding to the polar teeth b;

[0024] There are 1 - 5 of the described pole teeth e, and the g is provided corresponding to the pole teeth e; there are 1 - 5 of the pole teeth f, and the pole teeth h is provided corresponding to the pole teeth f;

[0025] There are 1 - 5 of the described pole teeth i, and the pole teeth k is provided corresponding to the pole teeth i; there are 1 - 5 of the pole teeth j, and the pole teeth l is provided corresponding to the pole teeth j;

[0026] There are 1 - 5 of the described pole teeth m, and the pole teeth o is provided corresponding to the pole teeth m; there are 1 - 5 of the pole teeth n, and the pole teeth p is provided corresponding to the pole teeth n;

[0027] There are 1 - 5 of the described pole teeth q, and the pole teeth s is provided corresponding to the pole teeth q; there are 1 - 5 of the pole teeth r, and the pole teeth t is provided corresponding to the pole teeth r;

[0028] There are 1 - 5 of the described pole teeth u, and the pole teeth w is provided corresponding to the pole teeth u; there are 1 - 5 of the pole teeth v, and the pole teeth x is provided corresponding to the pole teeth v.

[0029] The shaft is made of non - magnetic material.

[0030] There are annular grooves Ⅰ on the outer circumferential surfaces of the first pole shoe ring, the second pole shoe ring, the third pole shoe ring, and the fourth pole shoe ring, and sealing ring I is provided in the annular grooves Ⅰ.

[0031] The first permanent magnet ring, the second permanent magnet ring, and the third permanent magnet ring are axially magnetized permanent magnets; the magnetic field lines of the first permanent magnet ring and the second permanent magnet ring are in opposite directions, and the magnetic field lines of the first permanent magnet ring and the third permanent magnet ring are in the same direction.

[0032] The described divergent split - tooth stepped magneto - hydrodynamic rotary sealing device further includes a left bearing sleeve, a right bearing sleeve, a left bearing, and a right bearing. The left bearing sleeve and the right bearing sleeve are provided on the inner wall of the housing. The left bearing sleeve is located on the left side of the first pole shoe ring and contacts the left end face of the first pole shoe ring. The left bearing is provided in the left bearing sleeve, the inner ring of the left bearing is sleeved on the shaft, and the outer ring of the left bearing contacts the inner ring of the left bearing sleeve; the right bearing sleeve is located on the right side of the fourth pole shoe ring and contacts the right end face of the fourth pole shoe ring. The right bearing is provided in the right bearing sleeve, the inner ring of the right bearing is sleeved on the shaft, and the outer ring of the right bearing contacts the inner ring of the right bearing sleeve.

[0033] The described divergent split-tooth stepped magnetorheological fluid rotary seal device further includes a left spacer sleeve and a right spacer sleeve; an annular groove II is provided on the right end surface of the inner circular surface of the left bearing, the annular groove II is located on the right side of the left bearing, the left spacer sleeve is arranged in the annular groove II, and the right end surface of the left spacer sleeve contacts the left side wall of the first pole shoe ring; an annular groove III is provided on the right end surface of the inner circular surface of the right bearing, the annular groove III is located on the right side of the right bearing, the right spacer sleeve is arranged in the annular groove III, and the right end surface of the right spacer sleeve contacts the right side wall of the fourth pole shoe ring.

[0034] Annular grooves IV are provided on the outer circular surfaces of the left spacer sleeve and the right spacer sleeve, and sealing rings II are arranged in the annular grooves IV.

[0035] The applicable range of the present invention is relatively wide and can be applicable to rotating shafts with a radius of 10 to 300 mm.

[0036] The present invention adopts a divergent split-tooth stepped magnetorheological fluid rotary seal device with a unique structure. By adding a sleeve structure and changing the leakage path, an axial sealing gap is formed between the axial pole teeth of the sleeve and the pole teeth of the pole shoe. Permanent magnets are embedded between the pole shoes, and magnetorheological fluid is injected into the axial sealing gap formed between the pole shoe and the sleeve. Under the action of the permanent magnets, multiple "O"-shaped sealing rings are formed here to achieve the sealing effect and improve the sealing pressure resistance ability, thereby realizing a divergent split-tooth stepped magnetorheological fluid rotary seal device.

[0037] Most of the existing seal devices improve the pressure resistance value by reducing the sealing gap value, thereby reducing the magnetic resistance generated by the sealing gap, resulting in an increase in the magnetic flux density, and then the sealing pressure resistance value is improved. However, under heavy loads, large radial runout will definitely occur in the radial direction, resulting in the failure of the magnetorheological fluid seal. When designing the present invention, the material of the shaft is first changed to a non-magnetic material. According to the magnetic circuit theorem, the magnetic circuit goes from the N pole of the permanent magnet through the axial gap of the pole shoe to the sleeve and then returns to the S pole of the permanent magnet. Since the shaft of the present invention is made of non-magnetic material, when the magnetic circuit passes through the radial gap, the radial magnetic resistance increases sharply, and the magnetic circuit will pass through the axial gap more, so the magnetic flux concentrating effect of the axial gap will be more obvious.

[0038] The sleeve of the present invention is in threaded fit with the shaft. Compared with a stepped shaft, this can increase the axial height without increasing the stress concentration, thereby increasing the number of axial pole teeth and increasing the sealing pressure resistance value. Moreover, the way of staggering the split pole teeth of the present invention greatly improves the magnetic flux concentrating effect, effectively reduces the loss of the magnetorheological fluid volume, and also reduces the influence of the centrifugal force on the magnetorheological fluid. The present invention also has greatly improved self-healing of the magnetorheological fluid seal, greatly reduces the magnetorheological fluid that can be taken away when the magnetorheological fluid seal fails, further improves the pressure resistance ability and sealing reliability of the magnetorheological fluid seal under rotary sealing conditions, and expands its safe working range.

[0039] The present invention can effectively solve the problems of insufficient pressure resistance of the sealing device, low magnetic focusing effect, and serious loss of magnetic fluid under the condition of a large gap of the rotating shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic structural diagram of the sealing device described in the present invention.

[0041] The numbers and corresponding names marked in the figure are as follows:

[0042] 1 - shaft, 2 - housing, 3 - first pole shoe ring, 4 - second pole shoe ring, 5 - third pole shoe ring, 6 - fourth pole shoe ring, 7 - first sleeve, 8 - second sleeve, 9 - third sleeve, 10 - first permanent magnet ring, 11 - second permanent magnet ring, 12 - third permanent magnet ring, 13 - concave surface I, 14 - concave surface II, 15 - pole tooth a, 16 - pole tooth b, 17 - pole tooth c, 18 - pole tooth d, 19 - pole tooth e, 20 - pole tooth f, 21 - pole tooth g, 22 - pole tooth h, 23 - concave surface III, 24 - concave surface IV, 25 - pole tooth i, 26 - pole tooth j, 27 - pole tooth k, 28 - pole tooth l, 29 - pole tooth m, 30 - pole tooth n, 31 - pole tooth o, 32 - pole tooth p, 33 - concave surface V, 34 - concave surface VI, 35 - pole tooth q, 36 - pole tooth r, 37 - pole tooth s, 38 - pole tooth t, 39 - pole tooth u, 40 - pole tooth v, 41 - pole tooth w, 42 - pole tooth x, 43 - seal ring II, 44 - seal ring I, 45 - left bearing sleeve, 46 - right bearing sleeve, 47 - left bearing, 48 - right bearing, 49 - left spacer, 50 - right spacer. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention will be further described below with reference to the accompanying drawings.

[0044] As Figure 1 shown, the divergent split - tooth stepped magnetic fluid rotary sealing device includes a shaft 1, a housing 2, a first pole shoe ring 3, a second pole shoe ring 4, a third pole shoe ring 5, a fourth pole shoe ring 6, a first sleeve 7, a second sleeve 8, a third sleeve 9, a first permanent magnet ring 10, a second permanent magnet ring 11, and a third permanent magnet ring 12;

[0045] The first pole shoe ring 3, the second pole shoe ring 4, the third pole shoe ring 5, and the fourth pole shoe ring 6 are sequentially arranged at intervals on the inner wall of the housing 2 from left to right. The first pole shoe ring 3, the second pole shoe ring 4, the third pole shoe ring 5, and the fourth pole shoe ring 6 extend radially towards the outer circular surface of the shaft 1 and leave a gap with the outer circular surface of the shaft 1;

[0046] The described first permanent magnet ring 10, second permanent magnet ring 11, and third permanent magnet ring 12 are respectively arranged on the inner wall of the housing 2; the first permanent magnet ring 10 is located between the first pole shoe ring 3 and the second pole shoe ring 4, and both ends of the first permanent magnet ring 10 are in contact with the first pole shoe ring 3 and the second pole shoe ring 4 respectively; the second permanent magnet ring 11 is located between the second pole shoe ring 4 and the third pole shoe ring 5, and both ends of the second permanent magnet ring 11 are in contact with the second pole shoe ring 4 and the third pole shoe ring 5 respectively; the third permanent magnet ring 12 is located between the third pole shoe ring 5 and the fourth pole shoe ring 6, and both ends of the third permanent magnet ring 12 are in contact with the third pole shoe ring 5 and the fourth pole shoe ring 6 respectively;

[0047] The described first sleeve 7, second sleeve 8, and third sleeve 9 are sequentially arranged on the outer cylindrical surface of the shaft 1 at intervals by thread fitting from left to right. The outer cylindrical surfaces of the first sleeve 7, second sleeve 8, and third sleeve 9 respectively correspond to the inner cylindrical surfaces of the first permanent magnet ring 10, second permanent magnet ring 11, and third permanent magnet ring 12; the radial heights of the first sleeve 7, second sleeve 8, and third sleeve 9 increase sequentially;

[0048] On the right end face of the first pole shoe ring 3, on the side close to the shaft 1, there is a concave surface Ⅰ 13, and on the left end face of the second pole shoe ring 4, on the side close to the shaft 1, there is a concave surface Ⅱ 14;

[0049] The concave surface Ⅰ 13 corresponds to the left end face of the first sleeve 7. On the concave surface Ⅰ 13, multiple groups of pole teeth a 15 and pole teeth b 16 are alternately arranged at intervals along its radial direction; on the left end face of the first sleeve 7, multiple groups of pole teeth c 17 and pole teeth d 18 are alternately arranged at intervals along the radial direction. The pole teeth a 15 and pole teeth b 16 extend axially to the right, and the pole teeth c 17 and pole teeth d 18 extend axially to the left; the right end face of the pole tooth a 15 corresponds to the left end face of the pole tooth c 17, and there is a gap between them, and this gap is filled with magnetic fluid; the right end face of the pole tooth b 16 corresponds to the left end face of the pole tooth d 18, and there is a gap between them, and this gap is filled with magnetic fluid;

[0050] The concave surface Ⅱ 14 corresponds to the right end face of the first sleeve 7. On the concave surface Ⅱ 14, multiple groups of pole teeth e 19 and pole teeth f 20 are alternately arranged at intervals along its radial direction; on the left end face of the first sleeve 7, multiple groups of pole teeth g 21 and pole teeth h 22 are alternately arranged at intervals along the radial direction. The pole teeth e 19 and pole teeth f 20 extend axially to the left, and the pole teeth g 21 and pole teeth h 22 extend axially to the right; the left end face of the pole tooth e 19 corresponds to the right end face of the pole tooth g 21, and there is a gap between them, and this gap is filled with magnetic fluid; the left end face of the pole tooth f 20 corresponds to the right end face of the pole tooth h 22, and there is a gap between them, and this gap is filled with magnetic fluid;

[0051] On the right end face of the second pole shoe ring 4, on the side close to the shaft 1, there is a concave surface III 23. On the left end face of the third pole shoe ring 5, on the side close to the shaft 1, there is a concave surface IV 24;

[0052] The concave surface III 23 corresponds to the left end face of the second sleeve 8. On the concave surface III 23, multiple groups of pole teeth i 25 and pole teeth j 26 are alternately arranged at intervals along its radial direction; on the left end face of the second sleeve 8, multiple groups of pole teeth k 27 and pole teeth l 28 are alternately arranged at intervals along the radial direction. The pole teeth i 25 and pole teeth j 26 extend axially to the right, and the pole teeth k 27 and pole teeth l 28 extend axially to the left; the right end face of the pole tooth i 25 corresponds to the left end face of the pole tooth j 27, and there is a gap between them, and this gap is filled with magnetic fluid; the right end face of the pole tooth k 26 corresponds to the left end face of the pole tooth l 28, and there is a gap between them, and this gap is filled with magnetic fluid;

[0053] The concave surface IV 24 corresponds to the right end face of the second sleeve 8. On the concave surface IV 24, multiple groups of pole teeth m 29 and pole teeth n 30 are alternately arranged at intervals along its radial direction; on the left end face of the second sleeve 8, multiple groups of pole teeth o 31 and pole teeth p 32 are alternately arranged at intervals along the radial direction. The pole teeth m 29 and pole teeth n 30 extend axially to the left, and the pole teeth o 31 and pole teeth p 32 extend axially to the right; the left end face of the pole tooth m 29 corresponds to the right end face of the pole tooth o 31, and there is a gap between them, and this gap is filled with magnetic fluid; the left end face of the pole tooth n 30 corresponds to the right end face of the pole tooth p 32, and there is a gap between them, and this gap is filled with magnetic fluid;

[0054] On the right end face of the third pole shoe ring 5, on the side close to the shaft 1, there is a concave surface V 33. On the left end face of the fourth pole shoe ring 6, on the side close to the shaft 1, there is a concave surface VI 34;

[0055] The concave surface V 33 corresponds to the left end face of the third sleeve 9. On the concave surface V 33, multiple groups of pole teeth q 35 and pole teeth r 36 are alternately arranged at intervals along its radial direction; on the left end face of the third sleeve 9, multiple groups of pole teeth s 37 and pole teeth t 38 are alternately arranged at intervals along the radial direction. The pole teeth q 35 and pole teeth r 36 extend axially to the right, and the pole teeth s 37 and pole teeth t 38 extend axially to the left; the right end face of the pole tooth q 35 corresponds to the left end face of the pole tooth s 37, and there is a gap between them, and this gap is filled with magnetic fluid; the right end face of the pole tooth r 36 corresponds to the left end face of the pole tooth t 38, and there is a gap between them, and this gap is filled with magnetic fluid;

[0056] The concave surface VI 34 corresponds to the right end face of the third sleeve 9. Multiple sets of pole teeth u39 and pole teeth v40 are alternately and spacedly arranged along the radial direction on the concave surface VI 34. Multiple sets of pole teeth w41 and pole teeth x42 are alternately and spacedly arranged along the radial direction on the left end face of the third sleeve 9. The pole teeth u39 and pole teeth v40 extend axially to the left, and the pole teeth w41 and pole teeth x42 extend axially to the right. The left end face of the pole tooth u39 corresponds to the right end face of the pole tooth w41, with a gap therebetween, and the gap is filled with magnetic fluid. The left end face of the pole tooth v40 corresponds to the right end face of the pole tooth x42, with a gap therebetween, and the gap is filled with magnetic fluid.

[0057] The magnetic fluid between the right end face of the pole tooth a15 and the left end face of the pole tooth c17 is distributed alternately with the magnetic fluid between the right end face of the pole tooth b16 and the left end face of the pole tooth d18 in the radial direction. The magnetic fluid between the left end face of the pole tooth e19 and the right end face of the pole tooth g21 is distributed alternately with the magnetic fluid between the left end face of the pole tooth f20 and the right end face of the pole tooth h22 in the radial direction.

[0058] The magnetic fluid between the right end face of the pole tooth i25 and the left end face of the pole tooth j27 is distributed alternately with the magnetic fluid between the right end face of the pole tooth k26 and the left end face of the pole tooth l28 in the radial direction. The magnetic fluid between the left end face of the pole tooth m29 and the pole tooth o31 is distributed alternately with the magnetic fluid between the left end face of the pole tooth n30 and the right end face of the pole tooth p32 in the radial direction.

[0059] The magnetic fluid between the right end face of the pole tooth q35 and the left end face of the pole tooth s37 is distributed alternately with the magnetic fluid between the right end face of the pole tooth r36 and the left end face of the pole tooth t38 in the radial direction. The magnetic fluid between the left end face of the pole tooth u39 and the right end face of the pole tooth w41 is distributed alternately with the magnetic fluid between the left end face of the pole tooth v40 and the right end face of the pole tooth x42 in the radial direction.

[0060] There are 1 - 5 pole teeth a15, and the pole teeth c17 are arranged corresponding to the pole teeth a15. There are 1 - 5 pole teeth b16 distributed, and the pole teeth d18 are arranged corresponding to the pole teeth b16.

[0061] There are 1 - 5 pole teeth e19, and the g21 are arranged corresponding to the pole teeth e19. There are 1 - 5 pole teeth f20, and the pole teeth h22 are arranged corresponding to the pole teeth f20.

[0062] There are 1 - 5 pole teeth i25, and the pole teeth k26 are arranged corresponding to the pole teeth i25. There are 1 - 5 pole teeth j27, and the pole teeth l28 are arranged corresponding to the pole teeth j27.

[0063] The described pole teeth m29 are provided with 1 - 5 pieces, and the pole teeth o31 are arranged corresponding to the pole teeth m29; the pole teeth n30 are provided with 1 - 5 pieces, and the pole teeth p32 are arranged corresponding to the pole teeth n30;

[0064] The described pole teeth q35 are provided with 1 - 5 pieces, and the pole teeth s37 are arranged corresponding to the pole teeth q35; the pole teeth r36 are provided with 1 - 5 pieces, and the pole teeth t38 are arranged corresponding to the pole teeth r36;

[0065] The described pole teeth u39 are provided with 1 - 5 pieces, and the pole teeth w41 are arranged corresponding to the pole teeth u39; the pole teeth v40 are provided with 1 - 5 pieces, and the pole teeth x42 are arranged corresponding to the pole teeth v40.

[0066] The shaft 1 is made of non - magnetic material.

[0067] On the outer circumferential surfaces of the first pole shoe ring 3, the second pole shoe ring 4, the third pole shoe ring 5, and the fourth pole shoe ring 6, there are annular grooves Ⅰ, and sealing rings I44 are arranged in the annular grooves Ⅰ.

[0068] The first permanent magnet ring 10, the second permanent magnet ring 11, and the third permanent magnet ring 12 are axially magnetized permanent magnets; the magnetic force line directions of the first permanent magnet ring 10 and the second permanent magnet ring 11 are opposite, and the magnetic force line directions of the first permanent magnet ring 10 and the third permanent magnet ring 12 are the same.

[0069] The described divergent split - tooth stepped magneto - fluid rotary sealing device further includes a left bearing sleeve 45, a right bearing sleeve 46, a left bearing 47, and a right bearing 48. The left bearing sleeve 45 and the right bearing sleeve 46 are arranged on the inner wall of the housing 2. The left bearing sleeve 45 is located on the left side of the first pole shoe ring 3 and contacts the left end face of the first pole shoe ring 3. The left bearing 47 is arranged in the left bearing sleeve 45, the inner ring of the left bearing 47 is sleeved on the shaft 1, and the outer ring of the left bearing 47 contacts the inner ring of the left bearing sleeve 45; the right bearing sleeve 46 is located on the right side of the fourth pole shoe ring 6 and contacts the right end face of the fourth pole shoe ring 6. The right bearing 48 is arranged in the right bearing sleeve 46, the inner ring of the right bearing 48 is sleeved on the shaft 1, and the outer ring of the right bearing 48 contacts the inner ring of the right bearing sleeve 46.

[0070] The described divergent split-tooth stepped magnetohydrodynamic rotary sealing device further includes a left spacer sleeve 49 and a right spacer sleeve 50; an annular groove II is provided on the right end surface of the inner circular surface of the left bearing 47, the annular groove II is located on the right side of the left bearing 47, the left spacer sleeve 49 is arranged in the annular groove II, and the right end surface of the left spacer sleeve 49 contacts the left side wall of the first pole shoe ring 3; an annular groove III is provided on the right end surface of the inner circular surface of the right bearing 48, the annular groove III is located on the right side of the right bearing 48, the right spacer sleeve 50 is arranged in the annular groove III, and the right end surface of the right spacer sleeve 50 contacts the right side wall of the fourth pole shoe ring 6.

[0071] Annular grooves IV are provided on the outer circular surfaces of the left spacer sleeve 49 and the right spacer sleeve 50, and sealing rings II 43 are arranged in the annular grooves IV.

Claims

1. A divergent split-tooth stepped magnetohydrodynamic rotary sealing device, comprising a shaft (1), a housing (2), a first pole shoe ring (3), a second pole shoe ring (4), a third pole shoe ring (5), a fourth pole shoe ring (6), a first sleeve (7), a second sleeve (8), a third sleeve (9), a first permanent magnet ring (10), a second permanent magnet ring (11), and a third permanent magnet ring (12), characterized in that: The first pole shoe ring (3), the second pole shoe ring (4), the third pole shoe ring (5), and the fourth pole shoe ring (6) are sequentially arranged at intervals on the inner wall of the housing (2) from left to right. The first pole shoe ring (3), the second pole shoe ring (4), the third pole shoe ring (5), and the fourth pole shoe ring (6) extend radially towards the outer circular surface of the shaft (1), leaving a gap between them and the outer circular surface of the shaft (1); The first permanent magnet ring (10), the second permanent magnet ring (11), and the third permanent magnet ring (12) are respectively arranged on the inner wall of the housing (2). The first permanent magnet ring (10) is located between the first pole shoe ring (3) and the second pole shoe ring (4), and both ends of the first permanent magnet ring (10) are in contact with the first pole shoe ring (3) and the second pole shoe ring (4) respectively. The second permanent magnet ring (11) is located between the second pole shoe ring (4) and the third pole shoe ring (5), and both ends of the second permanent magnet ring (11) are in contact with the second pole shoe ring (4) and the third pole shoe ring (5) respectively. The third permanent magnet ring (12) is located between the third pole shoe ring (5) and the fourth pole shoe ring (6), and both ends of the third permanent magnet ring (12) are in contact with the third pole shoe ring (5) and the fourth pole shoe ring (6) respectively; The first sleeve (7), the second sleeve (8), and the third sleeve (9) are sequentially arranged at intervals on the outer circular surface of the shaft (1) by screw fit from left to right. The outer circular surfaces of the first sleeve (7), the second sleeve (8), and the third sleeve (9) respectively correspond to the inner circular surfaces of the first permanent magnet ring (10), the second permanent magnet ring (11), and the third permanent magnet ring (12). The radial heights of the first sleeve (7), the second sleeve (8), and the third sleeve (9) increase sequentially; On the right end face of the first pole shoe ring (3), a concave surface Ⅰ (13) is provided on the side close to the shaft (1). On the left end face of the second pole shoe ring (4), a concave surface Ⅱ (14) is provided on the side close to the shaft (1); The concave surface I (13) corresponds to the left end face of the first sleeve (7). Multiple groups of pole teeth a (15) and pole teeth b (16) are alternately arranged at intervals along the radial direction of the concave surface I (13); multiple groups of pole teeth c (17) and pole teeth d (18) are alternately arranged at intervals along the radial direction of the left end face of the first sleeve (7). The pole teeth a (15) and pole teeth b (16) extend rightward along the axial direction, and the pole teeth c (17) and pole teeth d (18) extend leftward along the axial direction; the right end face of the pole tooth a (15) corresponds to the left end face of the pole tooth c (17), with a gap therebetween, and this gap is filled with magnetic fluid; the right end face of the pole tooth b (16) corresponds to the left end face of the pole tooth d (18), with a gap therebetween, and this gap is filled with magnetic fluid; The concave surface II (14) corresponds to the right end face of the first sleeve (7). Multiple groups of pole teeth e (19) and pole teeth f (20) are alternately arranged at intervals along the radial direction of the concave surface II (14); multiple groups of pole teeth g (21) and pole teeth h (22) are alternately arranged at intervals along the radial direction of the left end face of the first sleeve (7). The pole teeth e (19) and pole teeth f (20) extend leftward along the axial direction, and the pole teeth g (21) and pole teeth h (22) extend rightward along the axial direction; the left end face of the pole tooth e (19) corresponds to the right end face of the pole tooth g (21), with a gap therebetween, and this gap is filled with magnetic fluid; the left end face of the pole tooth f (20) corresponds to the right end face of the pole tooth h (22), with a gap therebetween, and this gap is filled with magnetic fluid; On the right end face of the second pole shoe ring (4), a concave surface III (23) is provided on the side close to the shaft (1), and on the left end face of the third pole shoe ring (5), a concave surface IV (24) is provided on the side close to the shaft (1); The concave surface III (23) corresponds to the left end face of the second sleeve (8). Multiple groups of pole teeth i (25) and pole teeth j (26) are alternately arranged at intervals along the radial direction of the concave surface III (23); multiple groups of pole teeth k (27) and pole teeth l (28) are alternately arranged at intervals along the radial direction of the left end face of the second sleeve (8). The pole teeth i (25) and pole teeth j (26) extend rightward along the axial direction, and the pole teeth k (27) and pole teeth l (28) extend leftward along the axial direction; the right end face of the pole tooth i (25) corresponds to the left end face of the pole tooth j (26), with a gap therebetween, and this gap is filled with magnetic fluid; the right end face of the pole tooth k (27) corresponds to the left end face of the pole tooth l (28), with a gap therebetween, and this gap is filled with magnetic fluid; The described concave surface Ⅳ (24) corresponds to the right end face of the second sleeve (8). Multiple sets of pole teeth m (29) and pole teeth n (30) are alternately arranged at intervals along the radial direction of the concave surface Ⅳ (24); on the left end face of the second sleeve (8), multiple sets of pole teeth o (31) and pole teeth p (32) are alternately arranged at intervals along the radial direction. The pole teeth m (29) and pole teeth n (30) extend leftward along the axial direction, and the pole teeth o (31) and pole teeth p (32) extend rightward along the axial direction; the left end face of the pole tooth m (29) corresponds to the right end face of the pole tooth o (31), with a gap therebetween, and this gap is filled with magnetic fluid; the left end face of the pole tooth n (30) corresponds to the right end face of the pole tooth p (32), with a gap therebetween, and this gap is filled with magnetic fluid; On the right end face of the described third pole shoe ring (5), on the side close to the shaft (1), there is a concave surface Ⅴ (33), and on the left end face of the described fourth pole shoe ring (6), on the side close to the shaft (1), there is a concave surface Ⅵ (34); The described concave surface Ⅴ (33) corresponds to the left end face of the third sleeve (9). Multiple sets of pole teeth q (35) and pole teeth r (36) are alternately arranged at intervals along the radial direction of the concave surface Ⅴ (33); on the left end face of the third sleeve (9), multiple sets of pole teeth s (37) and pole teeth t (38) are alternately arranged at intervals along the radial direction. The pole teeth q (35) and pole teeth r (36) extend rightward along the axial direction, and the pole teeth s (37) and pole teeth t (38) extend leftward along the axial direction; the right end face of the pole tooth q (35) corresponds to the left end face of the pole tooth s (37), with a gap therebetween, and this gap is filled with magnetic fluid; the right end face of the pole tooth r (36) corresponds to the left end face of the pole tooth t (38), with a gap therebetween, and this gap is filled with magnetic fluid; The described concave surface Ⅵ (34) corresponds to the right end face of the third sleeve (9). Multiple sets of pole teeth u (39) and pole teeth v (40) are alternately arranged at intervals along the radial direction of the concave surface Ⅵ (34); on the left end face of the third sleeve (9), multiple sets of pole teeth w (41) and pole teeth x (42) are alternately arranged at intervals along the radial direction. The pole teeth u (39) and pole teeth v (40) extend leftward along the axial direction, and the pole teeth w (41) and pole teeth x (42) extend rightward along the axial direction; the left end face of the pole tooth u (39) corresponds to the right end face of the pole tooth w (41), with a gap therebetween, and this gap is filled with magnetic fluid; the left end face of the pole tooth v (40) corresponds to the right end face of the pole tooth x (42), with a gap therebetween, and this gap is filled with magnetic fluid; The described shaft (1) is made of non-magnetic material; On the outer circumferential surfaces of the described first pole shoe ring (3), second pole shoe ring (4), third pole shoe ring (5), and fourth pole shoe ring (6), there are annular grooves Ⅰ, and sealing rings I (44) are arranged in the annular grooves Ⅰ.

2. The divergent split-tooth stepped magnetic fluid rotary sealing device according to claim 1, characterized in that: The magnetorheological fluid between the right end face of the pole tooth a (15) and the left end face of the pole tooth c (17) is staggeredly distributed in the radial direction with the magnetorheological fluid between the right end face of the pole tooth b (16) and the left end face of the pole tooth d (18); the magnetorheological fluid between the left end face of the pole tooth e (19) and the right end face of the pole tooth g (21) is staggeredly distributed in the radial direction with the magnetorheological fluid between the left end face of the pole tooth f (20) and the right end face of the pole tooth h (22). The magnetorheological fluid between the right end face of the pole tooth i (25) and the left end face of the pole tooth j (26) is staggeredly distributed in the radial direction with the magnetorheological fluid between the right end face of the pole tooth k (27) and the left end face of the pole tooth l (28); the magnetorheological fluid between the left end face of the pole tooth m (29) and the pole tooth o (31) is staggeredly distributed in the radial direction with the magnetorheological fluid between the left end face of the pole tooth n (30) and the right end face of the pole tooth p (32). The magnetorheological fluid between the right end face of the pole tooth q (35) and the left end face of the pole tooth s (37) is staggeredly distributed in the radial direction with the magnetorheological fluid between the right end face of the pole tooth r (36) and the left end face of the pole tooth t (38); the magnetorheological fluid between the left end face of the pole tooth u (39) and the right end face of the pole tooth w (41) is staggeredly distributed in the radial direction with the magnetorheological fluid between the left end face of the pole tooth v (40) and the right end face of the pole tooth x (42).

3. The divergent split-tooth stepped magnetorheological fluid rotary sealing device according to claim 1, characterized in that: The pole tooth a (15) is provided with 1 - 5, and the pole tooth c (17) is arranged corresponding to the pole tooth a (15); the pole tooth b (16) is distributed with 1 - 5, and the pole tooth d (18) is arranged corresponding to the pole tooth b (16). The pole tooth e (19) is provided with 1 - 5, and the pole tooth g (21) is arranged corresponding to the pole tooth e (19); the pole tooth f (20) is provided with 1 - 5, and the pole tooth h (22) is arranged corresponding to the pole tooth f (20). The pole tooth i (25) is provided with 1 - 5, and the pole tooth k (27) is arranged corresponding to the pole tooth i (25); the pole tooth j (26) is provided with 1 - 5, and the pole tooth l (28) is arranged corresponding to the pole tooth j (26). The pole tooth m (29) is provided with 1 - 5, and the pole tooth o (31) is arranged corresponding to the pole tooth m (29); the pole tooth n (30) is provided with 1 - 5, and the pole tooth p (32) is arranged corresponding to the pole tooth n (30). The pole tooth q (35) is provided with 1 - 5, and the pole tooth s (37) is arranged corresponding to the pole tooth q (35); the pole tooth r (36) is provided with 1 - 5, and the pole tooth t (38) is arranged corresponding to the pole tooth r (36). The pole tooth u (39) is provided with 1 - 5, and the pole tooth w (41) is arranged corresponding to the pole tooth u (39); the pole tooth v (40) is provided with 1 - 5, and the pole tooth x (42) is arranged corresponding to the pole tooth v (40).

4. The diverging split-tooth stepped magnetohydrodynamic rotary sealing device according to claim 1, characterized in that: The described first permanent magnet ring (10), second permanent magnet ring (11) and third permanent magnet ring (12) are axially magnetized permanent magnets; the magnetic field lines of the first permanent magnet ring (10) and the second permanent magnet ring (11) are in opposite directions, and the magnetic field lines of the first permanent magnet ring (10) and the third permanent magnet ring (12) are in the same direction.

5. The diverging split-tooth stepped magnetohydrodynamic rotary seal device according to claim 1, characterized in that: It further includes a left bearing sleeve (45), a right bearing sleeve (46), a left bearing (47) and a right bearing (48). The left bearing sleeve (45) and the right bearing sleeve (46) are arranged on the inner wall of the housing (2). The left bearing sleeve (45) is located on the left side of the first pole shoe ring (3) and contacts the left end face of the first pole shoe ring (3). The left bearing (47) is arranged in the left bearing sleeve (45). The inner ring of the left bearing (47) is sleeved on the shaft (1), and the outer ring of the left bearing (47) contacts the inner ring of the left bearing sleeve (45). The right bearing sleeve (46) is located on the right side of the fourth pole shoe ring (6) and contacts the right end face of the fourth pole shoe ring (6). The right bearing (48) is arranged in the right bearing sleeve (46). The inner ring of the right bearing (48) is sleeved on the shaft (1), and the outer ring of the right bearing (48) contacts the inner ring of the right bearing sleeve (46).

6. The divergent split-tooth stepped magneto-fluid rotary sealing device according to claim 5, characterized in that: It further includes a left spacer sleeve (49) and a right spacer sleeve (50). An annular groove II is provided on the right end of the inner end face of the left bearing (47). The annular groove II is located on the right side of the left bearing (47). The left spacer sleeve (49) is arranged in the annular groove II, and the right end face of the left spacer sleeve (49) contacts the left side wall of the first pole shoe ring (3). An annular groove III is provided on the left end of the inner end face of the right bearing (48). The annular groove III is located on the right side of the right bearing (48). The right spacer sleeve (50) is arranged in the annular groove III, and the right end face of the right spacer sleeve (50) contacts the right side wall of the fourth pole shoe ring (6).

7. The divergent split-tooth stepped magnetohydrodynamic rotary sealing device according to claim 6, characterized in that: Annular grooves IV are provided on the outer cylindrical surfaces of the left spacer sleeve (49) and the right spacer sleeve (50), and sealing rings II (43) are arranged in the annular grooves IV.

Images