Small diameter dual-axis magnetic fluid sealing device and assembly method

Abstract

The present invention relates to a small-diameter dual-axis magnetic fluid sealing device, comprising: an inner-axis magnetic fluid sealing device provided with an inner shaft, and an outer-axis magnetic fluid sealing device provided with an outer shaft; the outer-axis magnetic fluid sealing device and the inner-axis magnetic fluid sealing device are axially arranged in parallel; the inner-axis magnetic fluid sealing device comprises: an inner-axis transmission positioning seat sleeved outside the inner shaft and provided with a receiving hole penetrating with the right end, an inner-axis magnetic fluid sealing component arranged in the receiving hole, an inner-axis transmission bearing and a positioning mechanism; the outer shaft sleeved outside the inner shaft and the left end connected to the right end of the inner-axis transmission positioning seat. The small-diameter dual-axis magnetic fluid sealing device has a relatively small overall outer diameter, a simple magnetic field structure of the inner and outer shaft seals, and good magnetic field stability, and is suitable for vacuum equipment with small installation holes and small installation space.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic fluid sealing, in particular to a small-diameter double-axis magnetic fluid sealing device and an assembling method. Background Art

[0002] The function of a magnetic fluid sealing device is to transfer rotational motion into a sealed container, and it is often used for vacuum sealing. A general magnetic fluid sealing device can only input power through one transmission shaft. If two sets of power are required, two magnetic fluid sealing devices must be used, which is difficult to achieve on some equipment with limited space. A dual-axis magnetic fluid sealing device can transfer two sets of rotational motion from the atmosphere side to the vacuum side through a set of devices, and ensure vacuum sealing. The structure of a dual-axis magnetic fluid sealing device can be understood from a dual-axis magnetic fluid sealing device involved in the utility model of Chinese patent application 201420185965.8. In the dual-axis magnetic fluid sealing device, the inner diameters of the outer transmission bearing 22 and the outer shaft magnetic fluid sealing mechanism 32 are larger than the outer diameters of the inner transmission bearing 21 and the inner shaft magnetic fluid seal 31. The inner transmission shaft 11, the inner transmission shaft magnetic sealing component 31, the outer transmission shaft 12, the outer transmission shaft magnetic sealing component 32, and the coaxial housing 40 for installation of the two magnetic fluid sealing mechanisms are coaxially arranged inside and outside in sequence. The outer transmission bearing 22 is coaxially arranged on the outside of the inner transmission bearing 21. The inner diameters of the outer transmission bearing 22 and the outer transmission shaft magnetic sealing component 32 are larger than the outer diameters of the inner transmission bearing 21 and the inner transmission shaft magnetic sealing component 31. The inner diameter of the outer transmission bearing 22 is larger than the outer diameter of the inner transmission bearing 21. The outer ring of the inner transmission bearing 21 is positioned in the transmission inner cavity 60 of the outer transmission shaft 12. The outer ring positioning seat of the inner transmission bearing 21 is also the outer transmission shaft 12. When the magnetic fluid sealing magnetic field of the inner and outer transmission shafts is constructed and designed, the inner transmission shaft is Magnetic conductive materials, such as ferritic stainless steel, the closed sealing magnetic field of the inner shaft is between the inner shaft and the inner drive shaft magnetic sealing component 31, and the outer drive shaft is made of non-magnetic conductive materials; the outer shaft sealing requires adding a magnetic conductive material bushing and a positioning mechanism between the outer diameter of the outer drive shaft and the inner diameter of the outer drive shaft magnetic sealing component to construct a closed outer shaft magnetic field. The outer shaft sealing magnetic field structure is complex and requires the inner diameter of the shell 40 to be increased, thereby increasing the overall size; or the inner drive shaft is made of non-magnetic conductive materials and the outer drive shaft is made of magnetic conductive materials. The closed sealing magnetic field of the inner shaft is between the inner drive shaft sealing component 31 and the outer drive shaft 12, and the closed sealing magnetic field of the outer shaft is between the outer drive shaft magnetic sealing component 32 and the outer drive shaft 12; the non-magnetic conductive material of the inner drive shaft is usually made of austenitic stainless steel with low yield strength. In order to ensure the same inner shaft transmission torque, the inner drive shaft diameter needs to be increased a lot, thereby increasing the outer diameter of the overall structure. Therefore, it is an urgent problem to design a small-diameter dual-axis magnetic fluid sealing device and assembly method with a small overall outer diameter, simple inner and outer shaft sealing magnetic field structure, good magnetic field stability, and suitable for vacuum equipment with small installation holes and small installation space. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a small-diameter dual-axis magnetic fluid sealing device and an assembly method with a small overall outer diameter, simple inner and outer shaft sealing magnetic field structures, good magnetic field stability, and suitable for installing vacuum equipment with small vias and small installation spaces.

[0004] The specific technical solution of the present invention is:

[0005] A small-diameter double-axis magnetic fluid sealing device comprises: an inner-axis magnetic fluid sealing device provided with an inner shaft, and an outer-axis magnetic fluid sealing device provided with an outer shaft; the outer-axis magnetic fluid sealing device and the inner-axis magnetic fluid sealing device are axially arranged in parallel; the inner-axis magnetic fluid sealing device comprises: an inner-axis transmission positioning seat sleeved outside the inner shaft and provided with a receiving hole penetrating with the right end, an inner-axis magnetic fluid sealing component arranged in the receiving hole, an inner-axis transmission bearing and a positioning mechanism; the outer shaft sleeved outside the inner shaft and the left end of which is connected to the right end of the inner-axis transmission positioning seat.

[0006] Preferably, the outer shaft magnetic fluid sealing device comprises: an outer shaft transmission positioning seat which is sleeved on the outside of the outer shaft and has a connecting flange on the right end, an outer shaft magnetic fluid sealing assembly, an outer shaft transmission bearing and a positioning mechanism arranged between the outer shaft and the outer shaft transmission positioning seat; a flange which is connected to the right end of the inner shaft transmission positioning seat is provided at the left end of the outer shaft; the outer diameter of the inner shaft transmission positioning seat is equal to the outer diameter of the outer shaft transmission positioning seat; the outer diameter of the flange is smaller than the outer diameter of the inner shaft transmission positioning seat and the outer diameter of the outer shaft transmission positioning seat.

[0007] Preferably, the outer shaft magnetic fluid sealing assembly comprises: an outer shaft sealing magnetic pole provided with a plurality of outer shaft sealing ring grooves which are connected with the outer side periphery and distributed along the axial direction of the outer shaft, an outer shaft sealing magnetic block installed in the outer shaft sealing ring groove, a plurality of outer shaft sealing annular grooves provided on the outer shaft side periphery and distributed along the axial direction of the outer shaft, an outer shaft sealing gap provided between the inner side periphery of the outer shaft sealing magnetic pole and the outer shaft, and a magnetic fluid placed in the outer shaft sealing gap; the outer diameter of the outer shaft sealing magnetic pole is adapted to the inner hole diameter provided on the outer shaft transmission positioning seat; an outer shaft sealing O-ring is provided between the outer side periphery of the outer shaft sealing magnetic pole and the inner hole side periphery of the outer shaft transmission positioning seat; the outer shaft sealing magnetic pole is an integral outer shaft sealing magnetic pole, or a split outer shaft sealing magnetic pole composed of a plurality of outer shaft sealing sub-magnetic poles distributed along the axial direction of the outer shaft, the outer shaft sealing ring groove is one less than the outer shaft sealing sub-magnetic pole and is located one-to-one between two adjacent outer shaft sealing sub-magnetic poles.

[0008] Preferably, the outer shaft transmission bearing and positioning mechanism include: an outer shaft left transmission bearing installed on the left side of the outer shaft magnetic fluid seal assembly, an outer shaft seal first positioning sleeve with two ends correspondingly pressing against the left end of the outer shaft seal magnetic pole and the right end of the outer ring of the outer shaft left transmission bearing, a fixing ring pressing against the left end of the outer ring of the outer shaft left transmission bearing and connected to the inner hole side of the outer shaft transmission positioning seat, an outer shaft shoulder provided on the outer shaft and pressing against the left end of the inner ring of the outer shaft left transmission bearing, and an outer shaft right transmission bearing installed on the right side of the outer shaft magnetic fluid seal assembly. A dynamic bearing, an outer shaft sealing second positioning sleeve whose two ends correspond to each other and press against the right end of the outer shaft sealing magnetic pole and the left end of the outer ring of the outer shaft left transmission bearing, a retaining ring arranged at the right end of the outer shaft transmission positioning seat and blocking the right end of the outer ring of the outer shaft right transmission bearing, a stepped extension connecting seat connected with the right end of the outer shaft at a small end, an outer shaft wave spring washer whose two ends correspond to each other and press against the right end of the inner ring of the outer shaft right transmission bearing and the large end of the stepped extension connecting seat; the connection between the small end of the stepped extension connecting seat and the right end of the outer shaft is located in the inner hole of the outer shaft right transmission bearing.

[0009] Preferably, the inner shaft magnetic fluid sealing assembly comprises: an inner shaft sealing pole provided with a plurality of inner shaft sealing ring grooves communicating with the outer side periphery, an inner shaft sealing magnetic block installed in the inner shaft sealing ring groove, a plurality of inner shaft sealing annular grooves provided on the inner shaft side periphery and distributed axially along the inner shaft, an inner shaft sealing gap provided between the inner side periphery of the inner shaft sealing pole and the inner shaft, and a magnetic fluid placed in the inner shaft sealing gap; the outer diameter of the inner shaft sealing pole is adapted to the diameter of the accommodating hole; an inner shaft sealing O-ring is provided between the outer side periphery of the inner shaft sealing pole and the side periphery of the accommodating hole; the inner shaft sealing pole is an integral inner shaft sealing pole, or a split inner shaft sealing pole composed of a plurality of inner shaft sealing sub-poles distributed axially along the inner shaft, the inner shaft sealing ring groove is one less than the inner shaft sealing sub-poles and is located one-to-one between two adjacent inner shaft sealing sub-poles.

[0010] Preferably, the inner shaft transmission bearing and positioning mechanism include: an inner shaft shoulder provided on the inner shaft and located in the accommodating hole, a plurality of inner shaft transmission bearings installed on the right side of the inner shaft shoulder, a nut whose left end presses against the inner ring of the rightmost inner shaft transmission bearing and is threadedly connected to the inner shaft, a first inner shaft seal positioning sleeve whose left end presses against the outer ring of the rightmost inner shaft transmission bearing, a second inner shaft seal positioning sleeve, an inner shaft wave spring washer, and a stabilizing bearing installed between the inner shaft and the stepped extension connecting seat; an inner shaft magnetic fluid seal assembly is installed on the left side of the inner shaft shoulder, and two ends of the inner shaft wave spring washer press against the left end of the inner shaft seal magnetic pole and the bottom surface of the accommodating hole in a one-to-one manner; two ends of the second inner shaft seal positioning sleeve press against the right end of the inner shaft seal magnetic pole and the outer ring of the leftmost inner shaft transmission bearing in a one-to-one manner.

[0011] Preferably, the outer shaft further comprises: a locking gland which presses against the outer ring of the stabilizing bearing and is connected to the right end of the stepped extending connecting seat.

[0012] Preferably, a connecting sealing O-ring and a positioning stop are provided between the right end of the inner shaft transmission positioning seat and the left end of the flange.

[0013] Preferably, the left end of the connecting flange is provided with a mounting sealing O-ring; and the connecting flange is provided with a plurality of connecting holes.

[0014] A method for assembling a small-diameter dual-axis magnetic fluid sealing device, wherein the small-diameter dual-axis magnetic fluid sealing device is the small-diameter dual-axis magnetic fluid sealing device described above, (1) pressing an inner shaft transmission bearing onto the inner shaft from the atmospheric side, positioning the inner ring of the inner shaft transmission bearing at the inner shaft shoulder and locking it with a nut, assembling the inner shaft seal second positioning sleeve, the inner shaft magnetic fluid sealing assembly and the inner shaft wave spring washer from the vacuum side. Assembling the inner shaft transmission positioning seat from the vacuum side to the atmospheric side, inserting the inner shaft seal second positioning sleeve from the atmospheric side to the vacuum side, connecting the sealing O-ring and the outer shaft, and locking the outer shaft and the inner shaft transmission positioning seat with screws, Ensure that the end faces of the outer shaft and the inner shaft transmission positioning seat are tightly fitted; (2) Insert the fixing ring on the outer shaft from the atmospheric side, press the outer shaft left transmission bearing from the atmospheric side, and position the inner ring of the outer shaft left transmission bearing at the outer shaft shoulder, then assemble the outer shaft seal first positioning sleeve, the outer shaft magnetic fluid seal assembly and the outer shaft seal second positioning sleeve, press the outer shaft right transmission bearing, assemble the outer shaft transmission positioning seat from the atmospheric side to the vacuum side and the retaining ring covers the outer ring of the outer shaft right transmission bearing, lock the fixing ring with screws, and then assemble the outer shaft wave spring washer and the stepped extension connection seat from the atmospheric side. Ensure that the stepped extension connection seat is tightly fitted with the end face of the outer shaft, and lock the stepped extension connection seat with screws; (3) Assemble the stabilizing bearing and locking cover on the inner shaft from the atmospheric side. The locking cover presses the outer ring of the stabilizing bearing and is locked with the stepped extension connection seat with screws.

[0015] Compared with the prior art, the invention has the following beneficial effects: the outer shaft of the small-diameter dual-axis magnetic fluid sealing device is directly sleeved on the inner shaft, the inner shaft is provided with an inner shaft transmission bearing and an inner shaft magnetic fluid sealing assembly, the outer shaft transmission bearing and the outer shaft magnetic fluid sealing assembly are provided on the outer shaft, the outer shaft transmission bearing and the outer shaft magnetic fluid sealing assembly on the outer shaft are arranged side by side with the inner shaft transmission bearing and the inner shaft magnetic fluid sealing assembly on the inner shaft, the outer shaft transmission bearing is small in size, the outer diameter of the inner shaft transmission locating seat is equal to the outer diameter of the outer shaft transmission locating seat, the outer diameter of the flange is smaller than the outer diameter of the inner shaft transmission locating seat and the outer diameter of the outer shaft transmission locating seat, the inner shaft and the outer shaft are both made of magnetic conductive materials through which magnetic lines of force pass, the two magnetic fields are distributed side by side, and the directions of the N pole and the S pole of the magnetic block are both NS-SN or SN-NS; the overall outer diameter is small, the magnetic field structure of the inner and outer shaft seals is simple, the magnetic field stability is good, and it is suitable for vacuum equipment with small installation holes and small installation space. The inner ring and outer ring of the inner shaft transmission bearing, the inner ring and outer ring of the outer shaft left transmission bearing and the outer ring of the outer shaft right transmission bearing, and the outer ring of the stable bearing are all axially pressed and positioned, which is beneficial to ensure the coaxiality of the inner and outer shafts and reduce axial runout during operation, thereby improving the stability of the device. Compared with the utility model of the comparative document (Chinese patent application No. 201420185965.8), a dual-axis magnetic fluid sealing device is involved, including a coaxial housing 40, a magnetic sealing component 30, a transmission shaft 10 and a bearing 20. The magnetic sealing component 30 is arranged on both sides of the transmission shaft 10, and the bearing 20 is arranged at both ends of the magnetic sealing component 30. The transmission shaft 10 includes an inner transmission shaft 11 and an outer transmission shaft 12. The inner transmission shaft 11 penetrates the outer transmission shaft 12. The bearing 20 includes an inner transmission shaft bearing 21 and an outer transmission shaft bearing 22. The magnetic sealing component 30 includes an inner transmission shaft magnetic sealing component 31 and In the outer transmission shaft magnetic seal component 32), the magnetic fluid seal and transmission structure on the outer transmission shaft and the inner transmission shaft are arranged in a standard manner, that is, the two inner transmission bearings are arranged on both sides of the inner transmission shaft magnetic seal component, and the two outer transmission bearings are arranged on both sides of the outer transmission magnetic seal component. In this application, the arrangement of the magnetic fluid seal and transmission structure of the inner shaft is a cantilever structure, the inner shaft magnetic fluid seal component is on the vacuum side, and the inner shaft transmission bearing is on the atmosphere side; the arrangement of the magnetic fluid seal and transmission structure of the outer shaft is a standard structure, and the outer shaft magnetic fluid seal component is between the two transmission bearings. The inner shaft shoulder of the inner shaft is on the vacuum side, which is conducive to the inner shaft transmission bearing being pressed in from the atmosphere side to the vacuum side; the accommodating hole is provided at the right end of the inner shaft transmission positioning seat, which is conducive to the installation of parts from the vacuum side to the atmosphere side; the outer shaft shoulder of the outer shaft is on the vacuum side, which is conducive to the outer shaft transmission bearing being pressed in from the atmosphere side to the vacuum side; the retaining ring is at the right end of the outer shaft transmission positioning seat, which is conducive to the installation of parts from the atmosphere side to the vacuum side. A connecting flange with multiple connecting holes is convenient for connection with vacuum equipment; a sealing O-ring is installed at the left end of the connecting flange, which is convenient for sealing at the connection with the vacuum equipment.A stabilizing bearing is installed between the inner shaft and the stepped extension connecting seat, and the locking gland on the atmosphere side presses the outer ring of the stabilizing bearing and is connected to the right end of the stepped extension connecting seat. The connection between the small end of the stepped extension connecting seat and the right end of the outer shaft is located in the inner hole of the right transmission bearing of the outer shaft, which is conducive to the smooth rotation of the device and reduces axial runout. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] Figure 2 It is a schematic diagram of the structure of the inner shaft magnetic fluid sealing device and magnetic lines of force;

[0018] Figure 3 It is a structural schematic diagram of an outer shaft magnetic fluid sealing device and magnetic lines of force.

[0019] In the figure: inner shaft 1, outer shaft 2, accommodating hole 3, inner shaft transmission locating seat 4, connecting flange 5, outer shaft transmission locating seat 6, flange 7, outer shaft sealing ring groove 8, outer shaft sealing pole 9, outer shaft sealing magnetic block 10, outer shaft sealing annular groove 11, magnetic fluid 12, outer shaft sealing O-ring 13, outer shaft left transmission bearing 14, outer shaft sealing first locating spacer 15, fixing ring 16, outer shaft shoulder 17, outer shaft right transmission bearing 18, outer shaft sealing second locating spacer 19, retaining ring 20, stepped extension connecting seat 21, outer shaft wave spring Gasket 22, stabilizing bearing 23, locking gland 24, inner shaft sealing ring groove 25, inner shaft sealing pole 26, inner shaft sealing magnet block 27, inner shaft sealing annular groove 28, inner shaft sealing O-ring 29, inner shaft shoulder 30, inner shaft transmission bearing 31, nut 32, inner shaft sealing first positioning sleeve 33, inner shaft sealing second positioning sleeve 34, inner shaft wave spring washer 35, connecting sealing O-ring 36, installing sealing O-ring 37, connecting hole 38, inner shaft magnetic fluid sealing assembly 39, outer shaft magnetic fluid sealing assembly 40. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings.

[0021] As attached Figure 1 , Attachment Figure 2 , Attachment Figure 3 As shown: a small-diameter double-axis magnetic fluid sealing device, comprising: an inner shaft magnetic fluid sealing device provided with an inner shaft 1, and an outer shaft magnetic fluid sealing device provided with an outer shaft 2; the outer shaft magnetic fluid sealing device and the inner shaft magnetic fluid sealing device are axially arranged in parallel; the inner shaft magnetic fluid sealing device comprises: an inner shaft transmission positioning seat 4 which is sleeved outside the inner shaft 1 and provided with a receiving hole 3 which penetrates the right end, an inner shaft magnetic fluid sealing component 39 arranged in the receiving hole 3, an inner shaft transmission bearing and a positioning mechanism; the outer shaft 2 is sleeved outside the inner shaft 1 and the left end is connected to the right end of the inner shaft transmission positioning seat 4.

[0022] In this embodiment, the outer shaft magnetic fluid sealing device includes: an outer shaft transmission positioning seat 6 which is sleeved on the outside of the outer shaft 2 and has a connecting flange 5 at the right end, an outer shaft magnetic fluid sealing assembly 40, an outer shaft transmission bearing and a positioning mechanism arranged between the outer shaft 2 and the outer shaft transmission positioning seat 6; a flange 7 which is threadedly connected to the right end of the inner shaft transmission positioning seat 4 is provided at the left end of the outer shaft 2; the outer diameter of the inner shaft transmission positioning seat 4 is equal to the outer diameter of the outer shaft transmission positioning seat 6; the outer diameter of the flange 7 is smaller than the outer diameter of the inner shaft transmission positioning seat 4 and the outer diameter of the outer shaft transmission positioning seat 6.

[0023] The outer shaft magnetic fluid sealing component includes: an outer shaft sealing magnetic pole 9 provided with an outer shaft sealing ring groove 8 that penetrates the outer side, an outer shaft sealing magnetic block 10 installed in the outer shaft sealing ring groove 8, a plurality of outer shaft sealing annular grooves 11 provided on the side of the outer shaft 2 and distributed along the axial direction of the outer shaft 2, an outer shaft sealing gap provided between the inner side of the outer shaft sealing magnetic pole 9 and the outer shaft 2, and a magnetic fluid 12 placed in the outer shaft sealing gap; the outer diameter of the outer shaft sealing magnetic pole 9 is matched with the inner hole diameter gap provided in the outer shaft transmission positioning seat 6; an outer shaft sealing O-ring 13 is installed between the outer side of the outer shaft sealing magnetic pole 9 and the inner hole side of the outer shaft transmission positioning seat 6; the outer shaft sealing magnetic pole is a split outer shaft sealing magnetic pole composed of two outer shaft sealing sub-poles distributed along the axial direction of the outer shaft, and the outer shaft sealing ring groove is located between the two outer shaft sealing sub-poles.

[0024] The outer shaft transmission bearing and positioning mechanism include: an outer shaft left transmission bearing 14 installed on the left side of the outer shaft magnetic fluid seal assembly, an outer shaft seal first positioning spacer 15 with two ends correspondingly pressing against the left end of the outer shaft seal magnetic pole 9 and the right end of the outer ring of the outer shaft left transmission bearing 14, a fixing ring 16 pressing against the left end of the outer ring of the outer shaft left transmission bearing 14 and being screwed with the inner hole side of the outer shaft transmission positioning seat 6, an outer shaft shoulder 17 provided on the outer shaft 2 and pressing against the left end of the inner ring of the outer shaft left transmission bearing 14, an outer shaft right transmission bearing 18 installed on the right side of the outer shaft magnetic fluid seal assembly, and two The outer shaft sealing second positioning sleeve 19 corresponds to the right end of the outer shaft sealing pole 9 and the left end of the outer ring of the outer shaft left transmission bearing 14, the retaining ring 20 is arranged at the right end of the outer shaft transmission positioning seat 6 and blocks the right end of the outer ring of the outer shaft right transmission bearing 18, the small end of the stepped extension connecting seat 21 is screwed to the right end of the outer shaft 2, and the two ends correspond to the outer shaft wave spring washer 22 that presses the right end of the inner ring of the outer shaft right transmission bearing 18 and the large end of the stepped extension connecting seat 21; the connection between the small end of the stepped extension connecting seat 21 and the right end of the outer shaft 2 is located in the inner hole of the outer shaft right transmission bearing 18.

[0025] The inner shaft magnetic fluid seal assembly comprises: an inner shaft sealing pole 26 provided with an inner shaft sealing ring groove 25 which penetrates the outer side, an inner shaft sealing magnetic block 27 installed in the inner shaft sealing ring groove 25, a plurality of inner shaft sealing annular grooves 28 provided on the side of the inner shaft 1 and distributed along the axial direction of the inner shaft 1, an inner shaft sealing gap provided between the inner side of the inner shaft sealing pole 26 and the inner shaft 1, and a magnetic fluid 12 placed in the inner shaft sealing gap; the outer diameter is gap-matched with the diameter 3 of the accommodating hole; an inner shaft sealing O-ring 29 is provided between the outer side of the inner shaft sealing pole 26 and the side of the accommodating hole 3; the inner shaft sealing pole is a split inner shaft sealing pole composed of two inner shaft sealing sub-poles distributed along the axial direction of the inner shaft, and the inner shaft sealing ring groove is located between the two inner shaft sealing sub-poles.

[0026] The inner shaft transmission bearing and positioning mechanism include: an inner shaft shoulder 30 provided on the inner shaft 1 and located in the accommodating hole 3, two inner shaft transmission bearings 31 installed on the right side of the inner shaft shoulder 30, a nut 32 whose left end presses against the inner ring of one inner shaft transmission bearing 31 on the right side and is threadedly connected to the inner shaft 1, an inner shaft sealing first positioning sleeve 33 whose left end presses against the outer ring of one inner shaft transmission bearing 31 on the right side, an inner shaft sealing second positioning sleeve 34, an inner shaft wave spring washer 35, and a stabilizing bearing 23 installed between the inner shaft 1 and the stepped extension connecting seat 21; an inner shaft magnetic fluid sealing assembly is installed on the left side of the inner shaft shoulder 30, and two ends of the inner shaft wave spring washer 35 press against the left end of the inner shaft sealing magnetic pole 26 and the bottom surface of the accommodating hole 3 in a one-to-one manner; two ends of the inner shaft sealing second positioning sleeve 34 press against the right end of the inner shaft sealing magnetic pole 26 and the outer ring of one inner shaft transmission bearing 31 on the left side in a one-to-one manner.

[0027] The outer shaft 2 further comprises: a locking gland 24 which presses against the outer ring of the stabilizing bearing of the outer shaft 2 and is threadedly connected to the right end of the stepped extending connecting seat 21 .

[0028] A connecting sealing O-ring 36 and a positioning stop are provided between the right end of the inner shaft transmission positioning seat 4 and the left end of the flange 7 .

[0029] The left end of the connecting flange 5 is provided with a mounting sealing O-ring 37 ; the connecting flange 5 is provided with four connecting holes 38 .

[0030] A method for assembling a small-diameter dual-axis magnetic fluid sealing device, wherein the small-diameter dual-axis magnetic fluid sealing device is the above-mentioned small-diameter dual-axis magnetic fluid sealing device, (1) pressing an inner shaft transmission bearing 31 onto an inner shaft 1 from the atmospheric side, positioning the inner ring of the inner shaft transmission bearing 31 at the inner shaft shoulder 30 and locking it with a nut 32, assembling an inner shaft seal second positioning sleeve 34, an inner shaft magnetic fluid sealing assembly and an inner shaft wave spring washer 35 from the vacuum side. Assembling an inner shaft transmission positioning seat 4 from the vacuum side to the atmospheric side, inserting the inner shaft seal second positioning sleeve 34 from the atmospheric side to the vacuum side, connecting the sealing O-ring and the outer shaft 2, and locking the outer shaft 2 and the inner shaft transmission positioning seat 4 with screws, Ensure that the end faces of the outer shaft 2 and the inner shaft transmission positioning seat 4 fit tightly; (2) Insert the fixing ring 16 on the outer shaft 2 from the atmospheric side, press the outer shaft left transmission bearing 14 from the atmospheric side, and position the inner ring of the outer shaft left transmission bearing 14 at the shoulder of the outer shaft 2, then assemble the outer shaft sealing first positioning spacer 15, the outer shaft magnetic fluid sealing assembly and the outer shaft sealing second positioning spacer 19, press the outer shaft right transmission bearing 18, and assemble the outer shaft transmission positioning seat 6 and the retaining ring from the atmospheric side to the vacuum side. 20 Hold the outer ring of the outer shaft right transmission bearing 18, lock the fixing ring 16 with screws, and then assemble the outer shaft wave spring washer and the stepped extension connecting seat 21 from the atmospheric side. The stepped extension connecting seat 21 is ensured to fit tightly with the end face of the outer shaft 2, and the stepped extension connecting seat 21 is locked with screws; (3) Assemble the outer shaft 2 stabilizing bearing and locking cover on the inner shaft 1 from the atmospheric side. The locking cover presses against the outer ring of the outer shaft 2 stabilizing bearing and is locked with the stepped extension connecting seat 21 with screws.

[0031] In the description of the present invention, it is necessary to understand that the terms "left", "right", "up", "down", "horizontal", "top", "bottom", "inside", "outside", "circumferential", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In addition to the above-mentioned embodiments, within the scope disclosed in the claims and the specification of the present invention, the technical features or technical data of the present invention can be reselected and combined to form new embodiments, which can be achieved by those skilled in the art without creative work. Therefore, these embodiments that are not described in detail in the present invention should also be regarded as specific embodiments of the present invention and within the protection scope of the present invention.

Claims

1. A small diameter dual-axis magnetic fluid sealing device, comprising: An inner shaft magnetic fluid sealing device is provided with an inner shaft, and an outer shaft magnetic fluid sealing device is provided with an outer shaft; the characteristic is that the outer shaft magnetic fluid sealing device and the inner shaft magnetic fluid sealing device are axially arranged in parallel; the inner shaft magnetic fluid sealing device comprises: an inner shaft transmission positioning seat sleeved outside the inner shaft and provided with a receiving hole penetrating with the right end, an inner shaft magnetic fluid sealing component arranged in the receiving hole, an inner shaft transmission bearing and a positioning mechanism; the outer shaft sleeve is outside the inner shaft and the left end is connected with the inner shaft transmission positioning seat; the inner shaft transmission bearing and the positioning mechanism comprise: an inner shaft shoulder arranged on the inner shaft and located in the receiving hole, a plurality of inner shaft transmission bearings installed on the right side of the inner shaft shoulder, a nut with the left end pressing against the inner ring of the rightmost inner shaft transmission bearing and threadedly connected with the inner shaft, a first inner shaft sealing positioning sleeve with the left end pressing against the outer ring of the rightmost inner shaft transmission bearing, a second inner shaft sealing positioning sleeve, an inner shaft wave spring washer, and a stable bearing installed between the inner shaft and the stepped extension connection seat.

2. The small-diameter dual-axis magnetic fluid sealing device according to claim 1 is characterized in that: The outer shaft magnetic fluid sealing device comprises: an outer shaft transmission positioning seat which is sleeved outside the outer shaft and has a connecting flange at the right end, an outer shaft magnetic fluid sealing component, an outer shaft transmission bearing and a positioning mechanism which are arranged between the outer shaft and the outer shaft transmission positioning seat; a flange which is connected to the right end of the inner shaft transmission positioning seat is provided at the left end of the outer shaft; the outer diameter of the inner shaft transmission positioning seat is equal to the outer diameter of the outer shaft transmission positioning seat; and the outer diameter of the flange is smaller than the outer diameter of the inner shaft transmission positioning seat and the outer diameter of the outer shaft transmission positioning seat.

3. The small diameter dual-axis magnetic fluid sealing device according to claim 2 is characterized in that: The outer shaft magnetic fluid sealing assembly comprises: an outer shaft sealing magnetic pole provided with a plurality of outer shaft sealing ring grooves penetrating the outer side periphery and distributed along the axial direction of the outer shaft, an outer shaft sealing magnetic block installed in the outer shaft sealing ring groove, a plurality of outer shaft sealing annular grooves provided on the outer shaft side periphery and distributed along the axial direction of the outer shaft, an outer shaft sealing gap provided between the inner side periphery of the outer shaft sealing magnetic pole and the outer shaft, and a magnetic fluid placed in the outer shaft sealing gap; the outer diameter of the outer shaft sealing magnetic pole is adapted to the inner hole diameter provided on the outer shaft transmission positioning seat; an outer shaft sealing O-ring is provided between the outer side periphery of the outer shaft sealing magnetic pole and the inner hole side periphery of the outer shaft transmission positioning seat.

4. The small diameter dual-axis magnetic fluid sealing device according to claim 3 is characterized in that: The outer shaft transmission bearing and positioning mechanism include: an outer shaft left transmission bearing installed on the left side of the outer shaft magnetic fluid seal assembly, an outer shaft seal first positioning spacer with two ends correspondingly pressing against the left end of the outer shaft seal magnetic pole and the right end of the outer ring of the outer shaft left transmission bearing, a fixing ring pressing against the left end of the outer ring of the outer shaft left transmission bearing and connected to the inner hole side of the outer shaft transmission positioning seat, an outer shaft shoulder provided on the outer shaft and pressing against the left end of the inner ring of the outer shaft left transmission bearing, and an outer shaft right transmission shaft installed on the right side of the outer shaft magnetic fluid seal assembly. The outer shaft of the second shaft seal positioning sleeve has two ends correspondingly pressing against the right end of the outer shaft seal magnetic pole and the left end of the outer ring of the outer shaft left transmission bearing; a retaining ring is arranged at the right end of the outer shaft transmission positioning seat and blocks the right end of the outer ring of the outer shaft right transmission bearing; a stepped extension connecting seat with a small end connected to the right end of the outer shaft; an outer shaft wave spring washer with two ends correspondingly pressing against the right end of the inner ring of the outer shaft right transmission bearing and the large end of the stepped extension connecting seat; the connection between the small end of the stepped extension connecting seat and the right end of the outer shaft is located in the inner hole of the outer shaft right transmission bearing.

5. The small-diameter dual-axis magnetic fluid sealing device according to any one of claims 1 to 4, characterized in that: The inner shaft magnetic fluid sealing assembly comprises: an inner shaft sealing magnetic pole provided with a plurality of inner shaft sealing ring grooves penetrating with the outer side periphery, an inner shaft sealing magnetic block installed in the inner shaft sealing ring groove, a plurality of inner shaft sealing annular grooves provided on the inner shaft side periphery and distributed along the axial direction of the inner shaft, an inner shaft sealing gap provided between the inner side periphery of the inner shaft sealing magnetic pole and the inner shaft, and a magnetic fluid placed in the inner shaft sealing gap; the outer diameter of the inner shaft sealing magnetic pole is adapted to the diameter of the accommodating hole; an inner shaft sealing O-ring is provided between the outer side periphery of the inner shaft sealing magnetic pole and the side periphery of the accommodating hole.

6. The small diameter dual-axis magnetic fluid sealing device according to claim 5 is characterized in that: The shaft magnetic fluid seal assembly is installed on the left side of the inner shaft shoulder, and the two ends of the inner shaft wave spring washer press against the left end of the inner shaft seal magnetic pole and the bottom surface of the accommodating hole one by one; the two ends of the inner shaft seal second positioning spacer press against the right end of the inner shaft seal magnetic pole and the outer ring of the leftmost inner shaft transmission bearing one by one.

7. The small-diameter dual-axis magnetic fluid sealing device according to claim 6 is characterized in that: The outer shaft also includes a locking gland which presses against the outer ring of the stabilizing bearing and is connected to the right end of the stepped extending connecting seat.

8. The small-diameter dual-axis magnetic fluid sealing device according to any one of claims 1 to 4, characterized in that: A connecting sealing O-ring and a positioning stop are provided between the right end of the inner shaft transmission positioning seat and the left end of the flange.

9. The small-diameter dual-axis magnetic fluid sealing device according to any one of claims 2 to 4, characterized in that: The left end of the connecting flange is provided with an installation sealing O-ring; the connecting flange is provided with a plurality of connecting holes.

10. A method for assembling a small-diameter dual-axis magnetic fluid sealing device, wherein the small-diameter dual-axis magnetic fluid sealing device is the small-diameter dual-axis magnetic fluid sealing device according to any one of claims 1 to 9, wherein: (1) Press the inner shaft transmission bearing into the inner shaft from the atmospheric side, locate the inner ring of the inner shaft transmission bearing at the inner shaft shoulder and tighten it with a nut, assemble the inner shaft seal second positioning sleeve, the inner shaft magnetic fluid seal assembly and the inner shaft wave spring washer from the vacuum side. Assemble the inner shaft transmission positioning seat from the vacuum side to the atmospheric side, insert the inner shaft seal second positioning sleeve from the atmospheric side to the vacuum side, connect the sealing O-ring and the outer shaft, and tighten the outer shaft and the inner shaft transmission positioning seat with screws. Ensure that the end faces of the outer shaft and the inner shaft transmission positioning seat are tightly fitted; (2) Insert the fixing ring on the outer shaft from the atmospheric side, press the outer shaft left transmission bearing from the atmospheric side, and position the inner ring of the outer shaft left transmission bearing at the outer shaft shoulder, then assemble the outer shaft seal first positioning sleeve, the outer shaft magnetic fluid seal assembly and the outer shaft seal second positioning sleeve, press the outer shaft right transmission bearing, assemble the outer shaft transmission positioning seat from the atmospheric side to the vacuum side and the retaining ring covers the outer ring of the outer shaft right transmission bearing, lock the fixing ring with screws, and then assemble the outer shaft wave spring washer and the stepped extension connection seat from the atmospheric side. Ensure that the stepped extension connection seat is tightly fitted with the end face of the outer shaft, and lock the stepped extension connection seat with screws; (3) Assemble the stabilizing bearing and locking cover on the inner shaft from the atmospheric side. The locking cover presses the outer ring of the stabilizing bearing and is locked with the stepped extension connection seat with screws.

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