Magnetic fluid sealing structure with conical sealing gap

Abstract

The invention discloses a magnetofluid sealing structure with a conical sealing gap. The magnetofluid sealing structure comprises a conical shaft sleeve, a bearing assembly, a magnetofluid sealing assembly and a sealing cover assembly. And the size of the sealing gap can be flexibly adjusted by axially moving the magnetic conductive shaft sleeve, so that the sealing capability in practical application is convenient to adjust. Due to the design of the inclined sealing gap, the magnetic fluid is more uniformly distributed in the gap, the sealing pressure can be effectively improved, and leakage is prevented. A small hole is formed in the middle of each sealing magnetic pole, the pressure nitrogen is introduced, the pressure of the introduced nitrogen is gradually reduced from front to back, and the magnetic fluid sealing capacity of each magnetic pole is improved through introduction of the pressure nitrogen. According to the magnetofluid sealing structure with the conical sealing gap, the existing defects are overcome, the sealing gap is adjustable, and the sealing performance is effectively improved.

Description

Technical Field

[0001] The invention relates to a magnetic fluid sealing structure with a conical sealing gap. Background Art

[0002] A magnetic fluid seal is a device that uses magnetic fluid to form a sealing ring under the action of an external magnetic field. It has the advantages of low friction, long life, and zero leakage. Traditional magnetic fluid sealing devices usually adopt rectangular, triangular or trapezoidal tooth structures. The sealing gap is fixed and difficult to adjust, resulting in limited sealing pressure and unsatisfactory sealing effect in practical applications. In the prior art, although there are some improved magnetic fluid sealing structures, such as variable tooth width, multi-stage magnetic source and other designs, it is still difficult to adjust the sealing gap and the improvement of sealing performance is limited. Therefore, it is of great practical significance to develop a magnetic fluid sealing device that can flexibly adjust the sealing gap and improve the sealing performance.

[0003] In recent years, magnetic fluid sealing technology has made significant progress in the field of patents, but there are still some shortcomings. For example, the magnetic source staggered sleeve-type sealing device proposed by Patent No. 201811068685.8 optimizes the magnetic field distribution by staggering permanent magnets, thereby improving the sealing pressure resistance. However, its sealing gap adjustment is still relatively difficult and difficult to adapt to different working conditions, especially in situations where the sealing gap needs to be adjusted frequently. The existing design is not flexible enough. The new variable tooth magnetic fluid sealing structure designed by Patent No. 202210123456.7 optimizes the magnetic field distribution by changing the thickness and width of the pole teeth, significantly improving the sealing pressure, but its structure is complex, the processing is difficult, and the cost is high, making it difficult to promote in large-scale industrial applications.

[0004] Therefore, in order to solve the above problems, a magnetic fluid sealing structure with a conical sealing gap is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the existing defects and provide a magnetic fluid sealing structure with a conical sealing gap. The sealing gap is adjustable and the sealing performance is effectively improved.

[0006] To achieve the above object, the present invention provides the following technical solutions: a magnetic fluid sealing structure with a conical sealing gap, comprising a tapered sleeve, a bearing assembly, a magnetic fluid sealing assembly and a cover assembly;

[0007] The tapered sleeve is arranged on the outside of the rotating shaft, the bearing assembly is arranged on the upper end of the outer side of the rotating shaft, the magnetic fluid sealing assembly is arranged on the lower end of the outer side, and the cover assembly is respectively arranged on the upper end of the bearing assembly and the lower end of the magnetic fluid sealing assembly.

[0008] Preferably, the bearing assembly includes a first angular contact ball bearing and a second angular contact ball bearing, the first angular contact ball bearing and the second angular contact ball bearing are arranged at the upper end of the outer wall of the tapered sleeve, and the upper end of the first angular contact ball bearing is provided with a round nut for pre-tightening the bearing;

[0009] A bearing spacer is provided between the first angular contact ball bearing and the second angular contact ball bearing.

[0010] Preferably, a lip seal ring is provided at the lower end of the second angular contact ball bearing.

[0011] Preferably, the magnetic fluid sealing assembly includes a first pole shoe, a second pole shoe, a third pole shoe, a first permanent magnet, and a second permanent magnet;

[0012] The first pole shoe is provided at the lower end of the lip seal ring, the second pole shoe is provided at the lower end of the first pole shoe, and the third pole shoe is provided at the lower end of the second pole shoe;

[0013] The first permanent magnet is arranged between the first pole shoe and the second pole shoe, and the second permanent magnet is arranged between the second pole shoe and the third pole shoe;

[0014] A first magnetic isolation ring is provided between the first pole shoe and the lip seal ring; a second magnetic isolation ring is provided at the lower end of the third pole shoe.

[0015] Preferably, a first nitrogen channel is provided on the first magnetic isolation ring; a second nitrogen channel is provided on the first permanent magnet; a third nitrogen channel is provided on the second permanent magnet; and a fourth nitrogen channel is provided on the second magnetic isolation ring.

[0016] A first magnetic fluid injection port is provided on the first pole shoe; a second magnetic fluid injection port is provided on the second pole shoe; and a third magnetic fluid injection port is provided on the third pole shoe.

[0017] Preferably, the cover assembly includes an upper end cover, a shell and a lower end cover; the shell is arranged outside the bearing assembly and the magnetic fluid sealing assembly, the upper end cover is arranged on the upper end of the shell and is fastened by the upper end cover fixing screws; the lower end cover is arranged on the lower end and is fastened by the lower end cover fixing screws;

[0018] A cooling water space is provided in the shell, a cooling water inlet is provided on one side of the cooling water space, and a cooling water outlet is provided on the other side of the cooling water space.

[0019] Preferably, an O-ring is provided between the upper and lower ends of the inner wall of the tapered sleeve and the rotating shaft.

[0020] Preferably, a lubricating oil injection port is provided on the bearing spacer.

[0021] Preferably, a pressure detection channel is provided on the housing, and the pressure detection channel is connected to between the second angular contact ball bearing and the lip seal ring.

[0022] Compared with the prior art, the beneficial effects of the present invention are: the magnetic fluid sealing structure with a conical sealing gap has an adjustable sealing gap: by axially moving the magnetic sleeve, the size of the sealing gap can be flexibly adjusted, which is convenient for adjusting the sealing capacity in practical applications. Improved sealing performance: the inclined sealing gap design makes the distribution of the magnetic fluid in the gap more uniform, which can effectively increase the sealing pressure and prevent leakage. Introducing pressurized nitrogen in the middle of the sealing pole increases the sealing pressure: a small hole is opened in the middle of each sealing pole, and pressurized nitrogen is introduced. From front to back, the pressure of the introduced nitrogen gradually decreases, and the magnetic fluid sealing capacity of each pole is improved by the introduction of pressurized nitrogen. Simple structure: The structure is simple, easy to process and install, and suitable for the sealing needs of various rotating shafts. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 A cross-sectional view of a magnetic fluid sealing structure having a conical sealing gap according to the present invention;

[0025] Figure 2 It is a local detail diagram of the magnetic fluid sealing structure with a conical sealing gap of the present invention.

[0026] In the figure: 1, rotating shaft; 2, tapered sleeve; 3, upper end cover fixing screw; 4, upper end cover; 5, O-ring; 6, round nut; 7, first angular contact ball bearing; 71, second angular contact ball bearing; 8, bearing spacer; 9, lubricating oil injection port; 10, housing; 11, pressure detection channel; 12, lip seal; 13, first magnetic isolation ring; 131, second magnetic isolation ring; 14, cooling water outlet; 15, first pole shoe; 151, second pole shoe; 1 52. Third pole piece; 16. First permanent magnet; 161. Second permanent magnet; 17. Lower end cover fixing screw; 18. Lower end cover; 19. Cooling water inlet; 20. Cooling water space; 14. Cooling water outlet; 141. First nitrogen channel; 142. Second nitrogen channel; 143. Third nitrogen channel; 144. Fourth nitrogen channel; 145. First magnetic fluid injection port; 146. Second magnetic fluid injection port; 147. Third magnetic fluid injection port. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] See also Figure 1-2 A magnetic fluid sealing structure with a conical sealing gap includes a tapered sleeve 2, a bearing assembly, a magnetic fluid sealing assembly and a cover assembly; the tapered sleeve 2 is arranged on the outside of a rotating shaft 1, a bearing assembly is arranged on the upper end of the outer side of the rotating shaft 1, a magnetic fluid sealing assembly is arranged on the lower end of the outer side, and cover assemblies are respectively arranged on the upper end of the bearing assembly and the lower end of the magnetic fluid sealing assembly.

[0029] Specifically, O-rings 5 ​​are provided between the upper and lower ends of the inner wall of the tapered sleeve 2 and the rotating shaft 1 . The tapered sleeve 2 and the rotating shaft 1 are tightly fitted to form a whole and rotate together, with the O-ring 5 passing therebetween.

[0030] Specifically, the bearing assembly includes a first angular contact ball bearing 7 and a second angular contact ball bearing 71. The first and second angular contact ball bearings 7 and 71 are mounted on the upper end of the outer wall of the tapered sleeve 2. A round nut 6 is mounted on the upper end of the first angular contact ball bearing 7 to pre-tighten the bearings. A bearing spacer 8 is positioned between the first and second angular contact ball bearings 7 and 71. A lubricating oil inlet 9 is provided on the bearing spacer 8.

[0031] Specifically, a lip seal 12 is provided at the lower end of the second angular contact ball bearing 71. A pressure detection channel 11 is defined in the housing 10 and connects between the second angular contact ball bearing 71 and the lip seal 12. The lip seal 12 protects the first and second angular contact ball bearings 7, 71, ensuring concentricity and providing safety by preventing media from entering the sealed area. It can also function as a separate seal in the event of a magnetic fluid seal failure.

[0032] Specifically, the magnetic fluid sealing assembly includes a first pole shoe 15, a second pole shoe 151 and a third pole shoe 152, a first permanent magnet 16 and a second permanent magnet 161; the first pole shoe 15 is arranged at the lower end of the lip sealing ring 12, the second pole shoe 151 is arranged at the lower end of the first pole shoe 15, and the third pole shoe 152 is arranged at the lower end of the second pole shoe 151; the first permanent magnet 16 is arranged between the first pole shoe 15 and the second pole shoe 151, and the second permanent magnet 161 is arranged between the second pole shoe 151 and the third pole shoe 152; a first magnetic isolation ring 13 is arranged between the first pole shoe 15 and the lip sealing ring 12; and a second magnetic isolation ring 131 is arranged at the lower end of the third pole shoe 152.

[0033] Specifically, the inner surfaces of the first pole shoe 15 , the second pole shoe 151 and the third pole shoe 152 have the same taper as the outer surface of the tapered sleeve 2 , forming a sealing gap with parallel end faces, and the magnetic sleeve 2 can move axially to adjust the sealing gap.

[0034] Specifically, the first pole shoe 15 , the second pole shoe 151 , the third pole shoe 152 and the tapered sleeve 2 are all made of a material with good magnetic conductivity.

[0035] Specifically, the sealing gap formed between the tapered sleeve 2 and the first pole shoe 15 , the second pole shoe 151 and the third pole shoe 152 is ensured to be at least about 0.2 mm to 1.5 mm to achieve the best sealing effect.

[0036] Specifically, the tapered sleeve 2 and the first pole shoe 15 , the second pole shoe 151 and the third pole shoe 152 have the same taper to ensure that the two end surfaces of the formed sealing gap are parallel.

[0037] Specifically, a first nitrogen channel 141 is provided on the first magnetic isolation ring 13; a second nitrogen channel 142 is provided on the first permanent magnet 16; a third nitrogen channel 143 is provided on the second permanent magnet 161; and a fourth nitrogen channel 144 is provided on the second magnetic isolation ring 131. The nitrogen channels are located in the gaps and at both ends of adjacent pole shoes. The nitrogen pressure can be dynamically adjusted, which enables the magnetic fluid sealing component to maintain a stable pressure state and improve the sealing ability. A first magnetic fluid injection port 145 is provided on the first pole shoe 15; a second magnetic fluid injection port 146 is provided on the second pole shoe 151; and a third magnetic fluid injection port 147 is provided on the third pole shoe 152. The magnetic fluid is injected through the first magnetic fluid injection port 145, the second magnetic fluid injection port 146, and the third magnetic fluid injection port 147 and reaches the sealed gap formed between the top of the pole tooth and the shaft sleeve, achieving a sealing effect.

[0038] Specifically, the first permanent magnet 16 and the second permanent magnet 161 are made of neodymium iron boron, and a channel is provided in the circumferential direction for nitrogen to flow in.

[0039] Specifically, the cover assembly includes an upper end cap 4, a housing 10, and a lower end cap 18. The housing 10 is positioned outside the bearing assembly and magnetic fluid seal assembly. The upper end cap 4 is positioned at the upper end of the housing 10 and secured with upper end cap fixing screws 3. The lower end cap 18 is positioned at the lower end and secured with lower end cap fixing screws 17. A cooling water space 20 is provided within the housing 10. A cooling water inlet 19 is positioned on one side of the cooling water space 20, and a cooling water outlet 14 is positioned on the other side. The housing 10 is made of a non-magnetic material.

[0040] Specifically, the cooling water outlet 14 also serves as a total outlet for the first nitrogen channel 141, the second nitrogen channel 142, the third nitrogen channel 143, the fourth nitrogen channel 144, the first magnetic fluid injection port 145, the second magnetic fluid injection port 146, and the third magnetic fluid injection port 147. The specific implementation method is to respectively set a thin tube from the cooling water outlet 14 to each branch, which can ensure that nitrogen and magnetic fluid can be injected without affecting the cooling water circulation.

[0041] Specifically, the tapered sleeve 2 and the rotating shaft 1 are matched through an O-ring 5 seal. When the rotating shaft 1 moves, the tapered sleeve 2 rotates together with the rotating shaft 1; the first angular contact ball bearing 7 and the second angular contact ball bearing 72 are installed back to back, with a bearing spacer 8 in between; the bearing spacer 8 is provided with a lubricating oil injection port 9 for convenient injection of bearing lubricating oil; the round nut 6 is located above the first angular contact ball bearing 7 and the second angular contact ball bearing 72, and plays a pre-tightening role; the lip seal 12 is located between the first angular contact ball bearing 7 and the second angular contact ball bearing The lip seal 12 is located below the second angular contact ball bearing 72, and a pressure detection channel 11 is provided between the lip seal 12 and the second angular contact ball bearing 72; the magnetic fluid sealing assembly is located below the second angular contact ball bearing 72 and the lip seal 12, and is the sealing component that is first contacted by the sealed medium; the first pole shoe 15 and the second pole shoe 151 are connected in series and are located above the third pole shoe 152, and the first permanent magnet 16 and the second permanent magnet 161 are respectively provided between adjacent pole teeth, and the first magnetic isolation ring 13 and the second magnetic isolation ring 131 are respectively located above the first pole shoe 15 and below the third pole shoe 152.

[0042] This magnetic fluid sealing structure has a conical sealing gap, and the sealing gap is adjustable: by axially moving the magnetic sleeve, the size of the sealing gap can be flexibly adjusted, which is convenient for adjusting the sealing capacity in actual applications. Improved sealing performance: The inclined sealing gap design makes the distribution of the magnetic fluid in the gap more uniform, which can effectively increase the sealing pressure and prevent leakage. Introducing pressurized nitrogen in the middle of the sealing pole increases the sealing pressure: a small hole is opened in the middle of each sealing pole, and pressurized nitrogen is introduced. From front to back, the pressure of the introduced nitrogen gradually decreases. By introducing pressurized nitrogen, the magnetic fluid sealing capacity of each pole is improved. Simple structure: The structure is simple, easy to process and install, and suitable for the sealing needs of various rotating shafts.

[0043] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A magnetic fluid sealing structure with a conical sealing gap, characterized in that: It comprises a tapered shaft sleeve (2), a bearing assembly, a magnetic fluid sealing assembly and a cover assembly; The tapered sleeve (2) is arranged on the outside of the rotating shaft (1); the bearing assembly is arranged on the upper end of the outer side of the rotating shaft (1); the magnetic fluid sealing assembly is arranged on the lower end of the outer side; and the cover assembly is respectively arranged on the upper end of the bearing assembly and the lower end of the magnetic fluid sealing assembly.

2. The magnetic fluid sealing structure with a conical sealing gap according to claim 1, characterized in that: The bearing assembly comprises a first angular contact ball bearing (7) and a second angular contact ball bearing (71), wherein the first angular contact ball bearing (7) and the second angular contact ball bearing (71) are arranged at the upper end of the outer wall of the tapered sleeve (2), and a round nut (6) for pre-tightening the bearing is provided at the upper end of the first angular contact ball bearing (7); A bearing spacer (8) is provided between the first angular contact ball bearing (7) and the second angular contact ball bearing (71).

3. The magnetic fluid sealing structure with a conical sealing gap according to claim 2, characterized in that: A lip seal ring (12) is provided at the lower end of the second angular contact ball bearing (71).

4. The magnetic fluid sealing structure with a conical sealing gap according to claim 3, characterized in that: The magnetic fluid sealing assembly comprises a first pole shoe (15), a second pole shoe (151), a third pole shoe (152), a first permanent magnet (16), and a second permanent magnet (161); The first pole shoe (15) is provided at the lower end of the lip seal ring (12), the second pole shoe (151) is provided at the lower end of the first pole shoe (15), and the third pole shoe (152) is provided at the lower end of the second pole shoe (151); The first permanent magnet (16) is arranged between the first pole shoe (15) and the second pole shoe (151), and the second permanent magnet (161) is arranged between the second pole shoe (151) and the third pole shoe (152); A first magnetic isolation ring (13) is provided between the first pole shoe (15) and the lip seal ring (12); and a second magnetic isolation ring (131) is provided at the lower end of the third pole shoe (152).

5. The magnetic fluid sealing structure with a conical sealing gap according to claim 4, characterized in that: A first nitrogen channel (141) is provided on the first magnetic isolation ring (13); a second nitrogen channel (142) is provided on the first permanent magnet (16); a third nitrogen channel (143) is provided on the second permanent magnet (161); and a fourth nitrogen channel (144) is provided on the second magnetic isolation ring (131). A first magnetic fluid injection port (145) is provided on the first pole shoe (15); a second magnetic fluid injection port (146) is provided on the second pole shoe (151); and a third magnetic fluid injection port (147) is provided on the third pole shoe (152).

6. The magnetic fluid sealing structure with a conical sealing gap according to claim 5, characterized in that: The sealing cover assembly comprises an upper end cover (4), a housing (10) and a lower end cover (18); the housing (10) is arranged outside the bearing assembly and the magnetic fluid sealing assembly, the upper end cover (4) is arranged at the upper end of the housing (10) and is fastened by an upper end cover fixing screw (3); the lower end cover (18) is arranged at the lower end and is fastened by a lower end cover fixing screw (17); A cooling water space (20) is provided in the housing (10), and a cooling water inlet (19) is provided on one side of the cooling water space (20), and a cooling water outlet (14) is provided on the other side.

7. The magnetic fluid sealing structure with a conical sealing gap according to claim 1, characterized in that: An O-ring (5) is provided between the upper and lower ends of the inner wall of the tapered sleeve (2) and the rotating shaft (1).

8. The magnetic fluid sealing structure with a conical sealing gap according to claim 2, characterized in that: The bearing spacer (8) is provided with a lubricating oil injection port (9).

9. The magnetic fluid sealing structure with a conical sealing gap according to claim 6, characterized in that: A pressure detection channel (11) is provided on the housing (10), and the pressure detection channel (11) is connected to between the second angular contact ball bearing (71) and the lip seal ring (12).

Images