A symmetrical magnetic fluid sealing device

Abstract

The purpose of the present invention is to provide a symmetrical magnetic fluid sealing device, including a shaft, a housing, a left outer pole shoe ring, a left inner pole shoe ring, an intermediate pole shoe ring, a right outer pole shoe ring, a right inner pole shoe ring, and a permanent magnet ring. The present invention designs the inner circular surface of the outer pole shoe as a truncated cone surface, and combines the left and right truncated cone surfaces opened at both ends of the inner circular surface of the intermediate pole shoe into a triangular structure, and the combined triangular structure cooperates with the triangular circular rings of the left and right inner pole shoes, thereby realizing a symmetrical magnetic fluid sealing device. The sealing device of the present invention reduces the component force of the magnetic field force in the circumferential direction by changing the shape of the inner ring surface of the pole shoe, thereby reducing the starting torque of the magnetic fluid sealing device.

Description

Technical Field

[0001] The invention belongs to the field of mechanical engineering sealing, and in particular relates to a symmetrical magnetic fluid sealing device. Background Art

[0002] Magnetic fluid seals are widely used in aerospace, machinery, petroleum and other industries due to their advantages of low friction, zero leakage and simple structure. However, in extremely low temperature rotary motion occasions, the extremely low working temperature will cause the viscosity of the magnetic fluid to increase or even solidify, which will cause the starting torque of the magnetic fluid seal device to be too large, seriously affecting the performance of the magnetic fluid seal device.

[0003] One method of reducing the starting torque of a magnetic fluid rotary sealing device is to heat the magnetic fluid to reduce its working viscosity and thus reduce the starting torque of the magnetic fluid seal when the shaft rotates, such as the sealing device described in Reference 1 (Patent No. CN201610860626.9). Although the above patent can solve the problem of starting torque of magnetic fluid sealing devices, it requires the introduction of a new heating system, which increases the complexity and cost of magnetic fluid sealing devices. Summary of the invention

[0004] The invention provides a novel magnetic fluid sealing device, which reduces the component force of the magnetic field force in the circumferential direction by changing the inner annular surface shape of the pole shoe, thereby reducing the starting torque of the magnetic fluid sealing device.

[0005] The technical solution of the present invention is as follows:

[0006] The symmetrical magnetic fluid sealing device comprises a shaft, a housing, a left outer pole shoe ring, a left inner pole shoe ring, an intermediate pole shoe ring, a right outer pole shoe ring, a right inner pole shoe ring, and a permanent magnet ring;

[0007] The left outer pole shoe ring, the middle pole shoe ring, and the right outer pole shoe ring are arranged on the inner wall of the outer shell from left to right in sequence, and the left and right side walls of the middle pole shoe ring are in contact with the right side wall of the left outer pole shoe ring and the left side wall of the right outer pole shoe ring respectively; the left and right ends of the inner circular surface of the middle pole shoe ring are respectively provided with a frustum surface I, the inner circular surface of the left outer pole shoe ring is a frustum surface II, and the inner circular surface of the right outer pole shoe ring is a frustum surface III; the frustum surface II and the frustum surface I on the left side of the middle pole shoe ring form a triangular ring groove I with a triangular cross section; the frustum surface III and the frustum surface I on the right side of the middle pole shoe ring form a triangular ring groove II with a triangular cross section;

[0008] The left inner pole shoe ring and the right inner pole shoe ring are respectively mounted on the outer circumferential surface of the shaft; the left inner pole shoe ring is arranged at a position corresponding to the position between the left outer pole shoe ring and the middle pole shoe ring, and a frustum surface IV and a frustum surface V are arranged on the outer circumferential surface; the frustum surface IV and the frustum surface V form a ring body with a triangular cross section, extending into the triangular ring groove I, the frustum surface IV and the frustum surface II correspond to each other and leave a gap, the gap is filled with magnetic fluid, and the frustum surface V corresponds to the frustum surface I on the left side of the middle pole shoe ring and leaves a gap;

[0009] The right inner pole shoe ring is arranged at a position corresponding to the position between the right outer pole shoe ring and the middle pole shoe ring, and a frustum surface VI and a frustum surface VII are arranged on the outer circumferential surface thereof; the frustum surface VI and the frustum surface VII form a ring body with a triangular cross section, extending into the triangular ring groove II, the frustum surface VI and the frustum surface III correspond to each other and leave a gap, the gap is filled with magnetic fluid, and the frustum surface VII corresponds to the frustum surface I on the right side of the middle pole shoe ring and leaves a gap;

[0010] The permanent magnet ring is sleeved on the shaft and located between the left inner pole shoe ring and the right inner pole shoe ring. The left and right end faces of the permanent magnet ring are in contact with the right end face of the left inner pole shoe ring and the left end face of the right inner pole shoe ring respectively.

[0011] The cone angles of the frustum surface II and frustum surface III are 30-60 degrees, and the cone angles of the frustum surface IV and frustum surface VI correspond thereto and are also 30-60 degrees.

[0012] The cone angle of the frustum surface I is 15°-40°, and the cone angles of the frustum surface V and frustum surface VII correspond thereto and are also 15°-40°.

[0013] The gap between the frustum surface IV and the frustum surface II is 0.05-3 mm; the gap between the frustum surface V and the frustum surface I on the left side of the middle pole shoe ring is 0.05-3 mm;

[0014] The gap between the frustum surface VI and the frustum surface III is 0.05-3 mm; the gap between the frustum surface VII and the frustum surface I on the right side of the middle pole shoe ring is 0.05-3 mm.

[0015] The permanent magnet ring is an axially magnetized permanent magnet.

[0016] The outer circumferential surfaces of the left outer pole shoe ring and the right outer pole shoe ring are provided with an annular groove I, and a sealing ring I is arranged in the annular groove; the inner circumferential surfaces of the left inner pole shoe ring and the right inner pole shoe ring are provided with an annular groove II, and a sealing ring II is arranged in the annular groove.

[0017] The left outer pole shoe ring is flush with the left end surface of the left inner pole shoe ring, and the right outer pole shoe ring is flush with the right end surface of the right inner pole shoe ring.

[0018] The symmetrical stepped magnetic fluid sealing device also includes two groups of magnetic isolation rings I and magnetic isolation rings II; the magnetic isolation ring I is arranged on the inner wall of the shell, respectively located on the left side of the left outer pole shoe ring and the right side of the right outer pole shoe ring; the magnetic isolation ring II is arranged on the outer circular surface of the shaft, respectively located on the left side of the left outer pole shoe ring and the right side of the right outer pole shoe ring.

[0019] The symmetrical magnetic fluid sealing device also includes a left bearing and a right bearing; the left bearing and the right bearing are respectively mounted on the shaft, the left bearing is arranged on the left side of the magnetic isolation ring at the left end; the right bearing is arranged on the right side of the magnetic isolation ring at the right end.

[0020] The present invention realizes a symmetrical magnetic fluid sealing device by designing the inner circular surface of the outer pole shoe as a truncated cone surface and combining it with the left and right truncated cone surfaces opened at both ends of the inner circular surface of the middle pole shoe into a triangular structure. The combined triangular structure cooperates with the triangular rings of the left and right inner pole shoes.

[0021] The present invention overcomes the problem of large starting torque of the existing sealing device at low temperature, and compared with the sealing device introducing heat source and related components, the present invention has simple structure and low cost.

[0022] The present invention can also reduce the influence of centrifugal force on the pressure resistance performance of the sealing device, improve the sealing reliability of the magnetic fluid seal, and expand its safe working range. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the sealing device described in the present invention.

[0024] The serial numbers and corresponding names in the figure are as follows:

[0025] 1-shaft, 2-housing, 3-left outer pole shoe ring, 4-left inner pole shoe ring, 5-middle pole shoe ring, 6-right outer pole shoe ring, 7-right inner pole shoe ring, 8-permanent magnet ring, 9-circular table surface I, 10-circular table surface II, 11-circular table surface III, 12-circular table surface IV, 13-circular table surface V, 14-circular table surface VI, 15-circular table surface VII, 16-sealing ring I, 17-sealing ring II, 18-left bearing, 19-right bearing, 20-magnetic isolation ring I, 21-magnetic isolation ring II, 22-end cover. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] like Figure 1 As shown, the symmetrical magnetic fluid sealing device comprises a shaft 1, a housing 2, a left outer pole shoe ring 3, a left inner pole shoe ring 4, an intermediate pole shoe ring 5, a right outer pole shoe ring 6, a right inner pole shoe ring 7, and a permanent magnet ring 8;

[0028] The left outer pole shoe ring 3, the middle pole shoe ring 5, and the right outer pole shoe ring 6 are arranged on the inner wall of the outer shell 2 from left to right in sequence, and the left and right side walls of the middle pole shoe ring 5 are in contact with the right side wall of the left outer pole shoe ring 3 and the left side wall of the right outer pole shoe ring 6 respectively; the left and right ends of the inner circular surface of the middle pole shoe ring 5 are respectively provided with a frustum surface Ⅰ9, the inner circular surface of the left outer pole shoe ring 3 is a frustum surface Ⅱ10, and the inner circular surface of the right outer pole shoe ring 6 is a frustum surface Ⅲ11; the frustum surface Ⅱ10 and the frustum surface Ⅰ9 on the left side of the middle pole shoe ring 5 form a triangular ring groove Ⅰ with a triangular cross section; the frustum surface Ⅲ11 and the frustum surface Ⅰ9 on the right side of the middle pole shoe ring 5 form a triangular ring groove Ⅱ with a triangular cross section;

[0029] The left inner pole shoe ring 4 and the right inner pole shoe ring 7 are respectively sleeved on the outer circumferential surface of the shaft 1; the left inner pole shoe ring 4 is arranged at a position corresponding to the position between the left outer pole shoe ring 3 and the middle pole shoe ring 5, and a frustum surface IV12 and a frustum surface V13 are arranged on the outer circumferential surface; the frustum surface IV12 and the frustum surface V13 form a ring body with a triangular cross section, extending into the triangular ring groove I, the frustum surface IV12 and the frustum surface II10 correspond to each other and leave a gap, the gap is filled with magnetic fluid, and the frustum surface V13 and the frustum surface I9 on the left side of the middle pole shoe ring 5 correspond to each other and leave a gap;

[0030] The right inner pole shoe ring 7 is arranged at a position corresponding to the right outer pole shoe ring 6 and the middle pole shoe ring 5, and a frustum surface VI14 and a frustum surface VII15 are arranged on the outer circumferential surface thereof; the frustum surface VI14 and the frustum surface VII15 form a ring body with a triangular cross section, extending into the triangular ring groove II, the frustum surface VI14 and the frustum surface III11 correspond to each other and leave a gap, the gap is filled with magnetic fluid, and the frustum surface VII15 and the frustum surface I9 on the right side of the middle pole shoe ring 5 correspond to each other and leave a gap;

[0031] The permanent magnet ring 8 is sleeved on the shaft 1 and is located between the left inner pole shoe ring 4 and the right inner pole shoe ring 7. The left and right end faces of the permanent magnet ring 8 are in contact with the right end face of the left inner pole shoe ring 4 and the left end face of the right inner pole shoe ring 7 respectively.

[0032] The cone angles of the frustum surface II 10 and the frustum surface III 11 are 30-60 degrees, and the cone angles of the frustum surface IV 12 and the frustum surface VI 14 correspond thereto and are also 30-60 degrees.

[0033] The cone angle of the frustum surface I9 is ​​15°-40°, and the frustum surface V13 and frustum surface VII15 correspond thereto, and the cone angles are also 15°-40°.

[0034] The gap between the frustum surface IV12 and the frustum surface II10 is 0.05-3 mm; the gap between the frustum surface V13 and the frustum surface I9 on the left side of the middle pole shoe ring 5 is 0.05-3 mm;

[0035] The gap between the frustum surface VI14 and the frustum surface III11 is 0.05-3 mm; the gap between the frustum surface VII15 and the frustum surface I9 on the right side of the middle pole shoe ring 5 is 0.05-3 mm.

[0036] The permanent magnet ring 8 is an axially magnetized permanent magnet.

[0037] An annular groove I is provided on the outer circumferential surface of the left outer pole shoe ring 3 and the right outer pole shoe ring 6, and a sealing ring I16 is provided in the annular groove; an annular groove II is provided on the inner circumferential surface of the left inner pole shoe ring 4 and the right inner pole shoe ring 7, and a sealing ring II17 is provided in the annular groove.

[0038] The left end faces of the left outer pole shoe ring 3 and the left inner pole shoe ring 4 are flush with each other, and the right end faces of the right outer pole shoe ring 6 and the right inner pole shoe ring 7 are flush with each other.

[0039] The symmetrical stepped magnetic fluid sealing device also includes two groups of magnetic isolation rings I20 and magnetic isolation rings II21; the magnetic isolation rings I20 are arranged on the inner wall of the shell 2, respectively located on the left side of the left outer pole shoe ring 3 and on the right side of the right outer pole shoe ring 6; the magnetic isolation rings II21 are arranged on the outer circular surface of the shaft 1, respectively located on the left side of the left outer pole shoe ring 3 and on the right side of the right outer pole shoe ring 6.

[0040] The symmetrical magnetic fluid sealing device also includes a left bearing 18 and a right bearing 19; the left bearing 18 and the right bearing 19 are respectively mounted on the shaft 1, the left bearing 18 is arranged on the left side of the magnetic isolation ring 17 at the left end; the right bearing 19 is arranged on the right side of the magnetic isolation ring 17 at the right end.

Claims

1. A symmetrical magnetic fluid sealing device, comprising a shaft (1), a housing (2), a left outer pole shoe ring (3), a left inner pole shoe ring (4), an intermediate pole shoe ring (5), a right outer pole shoe ring (6), a right inner pole shoe ring (7), and a permanent magnet ring (8), characterized in that: The left outer pole shoe ring (3), the middle pole shoe ring (5), and the right outer pole shoe ring (6) are arranged on the inner wall of the housing (2) in sequence from left to right, and the left and right side walls of the middle pole shoe ring (5) are in contact with the right side wall of the left outer pole shoe ring (3) and the left side wall of the right outer pole shoe ring (6) respectively; the left and right ends of the inner circular surface of the middle pole shoe ring (5) are respectively provided with a frustum surface I (9), the inner circular surface of the left outer pole shoe ring (3) is a frustum surface II (10), and the inner circular surface of the right outer pole shoe ring (6) is a frustum surface III (11); the frustum surface II (10) and the frustum surface I (9) on the left side of the middle pole shoe ring (5) form a triangular ring groove I with a triangular cross section; the frustum surface III (11) and the frustum surface I (9) on the right side of the middle pole shoe ring (5) form a triangular ring groove II with a triangular cross section; The left inner pole shoe ring (4) and the right inner pole shoe ring (7) are respectively mounted on the outer circumferential surface of the shaft (1); the left inner pole shoe ring (4) is arranged at a position corresponding to the position between the left outer pole shoe ring (3) and the middle pole shoe ring (5), and a frustum surface IV (12) and a frustum surface V (13) are arranged on the outer circumferential surface; the frustum surface IV (12) and the frustum surface V (13) form a ring body with a triangular cross section, extending into the triangular ring groove I, the frustum surface IV (12) and the frustum surface II (10) correspond to each other and a gap is left, the gap is filled with magnetic fluid, and the frustum surface V (13) and the frustum surface I (9) on the left side of the middle pole shoe ring (5) correspond to each other and a gap is left; The right inner pole shoe ring (7) is arranged at a position corresponding to the right outer pole shoe ring (6) and the middle pole shoe ring (5), and a frustoconical surface VI (14) and a frustoconical surface VII (15) are provided on the outer circumferential surface thereof; the frustoconical surface VI (14) and the frustoconical surface VII (15) form a ring body with a triangular cross section, extending into the triangular ring groove II, the frustoconical surface VI (14) and the frustoconical surface III (11) correspond to each other and a gap is left, the gap is filled with magnetic fluid, and the frustoconical surface VII (15) and the frustoconical surface I (9) on the right side of the middle pole shoe ring (5) correspond to each other and a gap is left; The permanent magnet ring (8) is sleeved on the shaft (1) and is located between the left inner pole shoe ring (4) and the right inner pole shoe ring (7), and the left and right end faces of the permanent magnet ring (8) are in contact with the right end face of the left inner pole shoe ring (4) and the left end face of the right inner pole shoe ring (7) respectively; The cone angles of the frustum surface II (10) and frustum surface III (11) are 30-60 degrees, and the cone angles of the frustum surface IV (12) and frustum surface VI (14) correspond thereto and are also 30-60 degrees; The cone angle of the frustum surface I (9) is 15°-40°, and the cone angles of the frustum surface V (13) and frustum surface VII (15) correspond thereto and are also 15°-40°.

2. The symmetrical magnetic fluid sealing device according to claim 1, characterized in that: The gap between the frustum surface IV (12) and the frustum surface II (10) is 0.05 to 3 mm; the gap between the frustum surface V (13) and the frustum surface I (9) on the left side of the middle pole shoe ring (5) is 0.05 to 3 mm; The gap between the frustum surface VI (14) and the frustum surface III (11) is 0.05-3 mm; the gap between the frustum surface VII (15) and the frustum surface I (9) on the right side of the middle pole shoe ring (5) is 0.05-3 mm.

3. The symmetrical magnetic fluid sealing device according to claim 1, characterized in that: The permanent magnet ring (8) is an axially magnetized permanent magnet.

4. The symmetrical magnetic fluid sealing device according to claim 1, characterized in that: An annular groove I is provided on the outer circumferential surface of the left outer pole shoe ring (3) and the right outer pole shoe ring (6), and a sealing ring I (16) is provided in the annular groove; an annular groove II is provided on the inner circumferential surface of the left inner pole shoe ring (4) and the right inner pole shoe ring (7), and a sealing ring II (17) is provided in the annular groove.

5. The symmetrical magnetic fluid sealing device according to claim 1, characterized in that: The left end surfaces of the left outer pole shoe ring (3) and the left inner pole shoe ring (4) are flush with each other, and the right end surfaces of the right outer pole shoe ring (6) and the right inner pole shoe ring (7) are flush with each other.

6. The symmetrical magnetic fluid sealing device according to claim 1, characterized in that: It also includes two groups of magnetic isolation rings I (20) and magnetic isolation rings II (21); the magnetic isolation ring I (20) is arranged on the inner wall of the outer shell (2), respectively located on the left side of the left outer pole shoe ring (3) and on the right side of the right outer pole shoe ring (6); the magnetic isolation ring II (21) is arranged on the outer circumferential surface of the shaft (1), respectively located on the left side of the left outer pole shoe ring (3) and on the right side of the right outer pole shoe ring (6).

7. The symmetrical magnetic fluid sealing device according to claim 6, characterized in that: The invention also comprises a left bearing (18) and a right bearing (19); the left bearing (18) and the right bearing (19) are respectively mounted on the shaft (1); the left bearing (18) is arranged on the left side of the magnetic isolation ring I (20) and the magnetic isolation ring II (21) at the left end; and the right bearing (19) is arranged on the right side of the magnetic isolation ring I (20) and the magnetic isolation ring II (21) at the right end.

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