Underwater robot walking wheel

Abstract

According to the underwater robot walking wheel, a bidirectional dynamic sealing barrier is formed through a two-stage back-to-back step sealing set, pressure self-adaptive balance is achieved in combination with a floating type sealing block, and the underwater robot walking wheel can resist electrochemical corrosion and is reliable in sealing; comprising a wheel shaft, a shaft body, a left shaft neck, a right shaft neck, a left shaft shoulder, a right shaft shoulder, a left shaft foot, a right shaft foot, a left fastening screw, a right fastening screw, an oil cavity, a left bearing sleeve, a right bearing sleeve, a left hub, a right hub, a left bearing, a right bearing, a left first baffle ring, a right first baffle ring, a left first step seal, a right first step seal, a left second step seal, a right second step seal and a left second baffle ring. The second right baffle ring, the left sealing block, the right sealing block, the first left inner side baffle ring, the first right inner side baffle ring, the first left inner step seal, the first right inner step seal, the second left inner step seal, the second right inner step seal, the second left inner side baffle ring, the second right inner side baffle ring, the sealing bolt hole and the sealing bolt are of a coaxial symmetry structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of underwater robots, and relates to an underwater robot walking wheel suitable for a deep water high-pressure environment. BACKGROUND

[0002] Currently, the underwater robot walking wheel is made by adding a sealing element based on a land walking wheel, and has certain defects, for example, a traditional single-stage seal has a sharp decline in sealing reliability in an underwater environment deeper than 300 meters (actual measurement data: a leakage rate > 3 mL / h at a depth of 500 meters) and is prone to failure; metal components are prone to electrochemical corrosion underwater; shaft deformation causes eccentric wear of the sealing surface; and unreasonable assembly gaps cause sand intrusion. SUMMARY

[0003] In view of the defects of the prior art, the application aims to provide an underwater robot walking wheel that is specifically suitable for a deep water environment, has a bidirectional dynamic sealing barrier formed by double-stage back-to-back Stellite seals, realizes pressure self-adaptive balance in combination with floating sealing blocks, and is resistant to electrochemical corrosion and has reliable sealing.

[0004] To solve the above problems, the application adopts the following technical scheme: An underwater robot walking wheel, characterized by comprising a wheel shaft, a shaft body, a left shaft neck, a right shaft neck, a left shaft shoulder, a right shaft shoulder, a left shaft foot, a right shaft foot, a left fastening screw rod, a right fastening screw rod, an oil cavity, a left bearing sleeve, a right bearing sleeve, a left wheel hub, a right wheel hub, a left bearing, a right bearing, a left first retainer ring, a right first retainer ring, a left first Stellite seal, a right first Stellite seal, a left second Stellite seal, a right second Stellite seal, a left second retainer ring, a right second retainer ring, a left sealing block, a right sealing block, a left first inner retainer ring, a right first inner retainer ring, a left first inner Stellite seal, a right first inner Stellite seal, a left second inner Stellite seal, a right second inner Stellite seal, a left second inner retainer ring, a right second inner retainer ring, a sealing bolt hole, and a sealing bolt, which are coaxially and symmetrically arranged. A left first retainer ring groove, a left first Stellite seal groove, a left second Stellite seal groove, and a left second retainer ring groove are arranged in the inner circle of the left shaft shoulder. A right first retainer ring groove, a right first Stellite seal groove, a right second Stellite seal groove, and a right second retainer ring groove are arranged in the inner circle of the right shaft shoulder. A left first inner retainer ring groove, a left first inner Stellite seal groove, a left second inner Stellite seal groove, and a left second inner retainer ring groove are arranged in the inner circle of the left sealing block. A right first inner retainer ring groove, a right first inner Stellite seal groove, a right second inner Stellite seal groove, and a right second inner retainer ring groove are arranged in the inner circle of the right sealing block. The diameter of the shaft body is greater than or equal to 5% to 50% (preferably 15%) of the diameters of the left shaft neck and the right shaft neck. The diameter of the left and right shoulder is 5% to 30% (preferably 12%) greater than the diameter of the left and right foot; The cross section of the left and right foot is runway-shaped; The cross section of the oil cavity shaft is symmetrically tapered, and the minimum diameter of the middle part of the oil cavity shaft is at least 1 mm; The cross section of the left and right bearing sleeve is symmetrically stepped, and the small-diameter part is interference-fitted with the outer ring of the left and right bearing (with an interference of 0.02 mm); The left and right bearings are respectively interference-fitted with the left and right journal (with an interference of 0.02 mm); The large-diameter inner side of the left bearing sleeve is provided with a left first blocking ring, a left first seal, a left second seal, and a left second blocking ring; The large-diameter inner side of the right bearing sleeve is provided with a right first blocking ring, a right first seal, a right second seal, and a right second blocking ring; The left sealing block is installed inside the left first blocking ring, the left first seal, the left second seal, and the left second blocking ring; The right sealing block is installed inside the right first blocking ring, the right first seal, the right second seal, and the right second blocking ring; The inner ring of the left and right hubs is uniformly distributed with not less than 3 reinforcing ribs; The sealing bolt hole penetrates the wall thickness of the oil cavity; The sealing bolt material of the left and right hubs, the left and right bearings, the left and right sealing blocks, and the sealing bolt hole is 304 stainless steel, UNS S2057 duplex stainless steel, or 18Ni 300 maraging steel; The left and right first and second seals are sealing elements composed of a slip ring and an O-ring; The sealing gasket of the sealing bolt is made of fluororubber or perfluoroether rubber.

[0005] Further, the inner hole roundness of the left and right bearing sleeves and the left and right sealing blocks is ≤ IT5 level, the coaxiality is ≤ 0.02 mm, the inner wall surface roughness Ra is ≤ 0.1 μm, Rz is ≤ 0.5 μm, and the waviness is ≤ 0.05 μm (test standard ISO 1101).

[0006] Further, the hole axis of the sealing bolt hole and the normal angle of the oil cavity wall surface is ≤ 30°.

[0007] Further, the wheel shaft, left bearing sleeve, right bearing sleeve, left sealing block, and right sealing block are subjected to WC-17Co cladding, nitriding, and DLC coating (coating thickness: 2-5 um).

[0008] Further, the left shaft shoulder, right shaft shoulder, outer wall of the left sealing block, and outer wall of the right sealing block have a straightness of ≤0.01 mm / m and coaxiality of ≤0.02 mm.

[0009] Further, the outer wall of the left sealing block and the outer wall of the right sealing block have a sealing end roughness Ra of ≤0.05 um.

[0010] The left shaft shoulder and the right shaft shoulder have a sealing end roughness Ra of ≤0.05 um, a non-sealing end roughness Ra of ≤0.4 um, and a gradual transition polishing in the transition zone from the sealing end to the non-sealing end.

[0011] Further, the left sealing block and the right sealing block have a bore diameter / left shaft shoulder and right shaft shoulder of ≥1:16.

[0012] Further, the left shaft shoulder and the right shaft shoulder have an assembly gap of 0.01 mm to 0.03 mm (preferably 0.015 mm) with the inner hole of the left sealing block and the right sealing block.

[0013] Further, the left sealing block and the right sealing block have an assembly gap of 0.01 mm to 0.03 mm with the large diameter of the left bearing sleeve and the right bearing sleeve.

[0014] Further, the sliding ring of the left first Ster seal, right first Ster seal, left second Ster seal, right second Ster seal, left inner first Ster seal, right inner first Ster seal, left inner second Ster seal, and right inner second Ster seal is made of PTFE filled with copper powder or carbon fiber (test standard ASTM D638), and the O-ring is made of perfluoroether rubber, and the O-ring has a low-temperature compression permanent deformation rate of <8% and a water absorption expansion rate of <1% at -40°C according to the standard ASTM D395 method B.

[0015] Further, the left first Ster seal and the left second Ster seal, the right first Ster seal and the right second Ster seal, the left inner first Ster seal and the left inner second Ster seal, and the right inner first Ster seal and the right inner second Ster seal are arranged back-to-back.

[0016] Further, the left first Ster seal, right first Ster seal, left second Ster seal, right second Ster seal, left inner first Ster seal, right inner first Ster seal, left inner second Ster seal, and right inner second Ster seal have an axial compression rate (pre-compression amount) of 10% to 20%.

[0017] Further, the slip ring of the left first stator seal, the right first stator seal, the left second stator seal, the right second stator seal, the left inner first stator seal, the right inner first stator seal, the left inner second stator seal, and the right inner second stator seal is a 2- to 4-piece split structure (preferably a 3-piece split structure).

[0018] Further, the split cut of the slip ring of the left first stator seal, the right first stator seal, the left second stator seal, the right second stator seal, the left inner first stator seal, the right inner first stator seal, the left inner second stator seal, and the right inner second stator seal has a roughness Ra≤10μm, the internal friction pair is treated with laser micro-pits (pits 50μm in diameter, pit center spacing 8mm to 24mm), and the external contact surface is mirror-polished to Ra≤0.04μm, and the non-contact surface is Ra≤1.64μm.

[0019] Further, the depth of the left first stator seal groove, the left second stator seal groove, the right first stator seal groove, the right second stator seal groove, the left first inner stator seal groove, the left second inner stator seal groove, the right first inner stator seal groove, and the right second inner stator seal groove is 0.1mm to 0.3mm greater than the axial thickness of the corresponding stator seal slip ring, and the radial gap is ≤0.1mm.

[0020] Further, the sealing surface roughness of the left first stator seal groove, the left second stator seal groove, the right first stator seal groove, the right second stator seal groove, the left first inner stator seal groove, the left second inner stator seal groove, the right first inner stator seal groove, and the right second inner stator seal groove is Ra≤0.4μm, the non-sealing surface is Ra≤1.6μm, the inlet chamfer is 20° to 30° (R0.2 to 0.5mm), and the root radius is R0.1mm to 0.3mm (test standard ASME B46.1).

[0021] Further, the material of the left first stop ring, the right first stop ring, the left second stop ring, the right second stop ring, the left first inner stop ring, the right first inner stop ring, the left second inner stop ring, and the right second inner stop ring is wear-resistant polyoxymethylene, or bronze powder and glass fiber filled polytetrafluoroethylene, or bronze powder and carbon fiber filled polytetrafluoroethylene, or glass fiber filled polyether ether ketone, or carbon fiber filled polyether ether ketone, with a hardness ≥HRC50.

[0022] Further, the width of the left first stop ring, the right first stop ring, the left second stop ring, the right second stop ring, the left first inner stop ring, the right first inner stop ring, the left second inner stop ring, and the right second inner stop ring is not less than 1.2 times the thickness of the adjacent stator seal slip ring, and the width tolerance is ±0.05mm, and the gap between the stop ring groove is ≤0.1mm (H8 / f8 fit).

[0023] Furthermore, the width of the left first retaining ring groove, left second retaining ring groove, right first retaining ring groove, right second retaining ring groove, left first inner retaining ring groove, left second inner retaining ring groove, right first inner retaining ring groove, and right second inner retaining ring groove is 0.2mm to 0.5mm larger than the corresponding retaining ring, and the depth is consistent with the thickness of the corresponding retaining ring (depth tolerance ±0.02mm).

[0024] Furthermore, the beneficial effects of this invention are as follows: This invention resists physical corrosion and deep water pressure by selecting suitable anti-corrosion and pressure-resistant materials; it significantly improves bending stiffness by forming a diameter gradient design (shaft diameter ≥ 5% to 50% of journal diameter) through the integrated axle body, left / right journals, left / right shoulders, and racetrack-shaped axle feet; it prevents water intrusion and lubricant leakage by setting back-to-back step seals on the inner side of the bearing sleeve as the first bidirectional seal and back-to-back step seals on the inner ring of the sealing block as the second bidirectional seal; it forms an anti-extrusion mechanism by using the retaining ring on the inner side of the bearing sleeve and the inner ring of the sealing block, and resists load impact by controlling machining and assembly precision; and it achieves pressure balance inside and outside the oil cavity through step seals, sealing blocks, and sealing bolts (external pressure squeezes the sealing block to make the pressure inside and outside the oil cavity tend to be consistent), and is expected to achieve a leakage rate of <0.01mL / h under 60MPa hydrostatic pressure (ISO 5208 standard). Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the split structure of the present invention.

[0026] Figure 2 This is a schematic diagram of the cross-sectional runway-shaped structure of the left and right axle feet of the present invention.

[0027] Figure 3 This is a cross-sectional schematic diagram of the oil cavity, hub, and left and right axle shoulders of the present invention.

[0028] Figure 4 These are schematic cross-sectional views of the left and right bearing sleeves of the present invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings.

[0030] like Figures 1 to 4As shown, an underwater robot walking wheel includes an axle (1), axle body (2), left journal (3), right journal (4), left shoulder (5), right shoulder (6), left foot (7), right foot (8), left fastening screw (9), right fastening screw (10), oil chamber (11), left bearing sleeve (12), right bearing sleeve (13), left hub (14), right hub (15), left bearing (16), right bearing (17), left first retaining ring (18), right first retaining ring (19), left first seal (20), and right first seal (21). 1) Left second seal (22), right second seal (23), left second retaining ring (24), right second retaining ring (25), left sealing block (26), right sealing block (27), left first inner retaining ring (28), right first inner retaining ring (29), left inner first seal (30), right inner first seal (31), left inner second seal (32), right inner second seal (33), left second inner retaining ring (34), right second inner retaining ring (35), sealing bolt hole (36), sealing bolt (37), forming a coaxial symmetrical structure; The inner ring of the left shoulder (5) is provided with a left first retaining ring groove (38), a left first step seal groove (40), a left second step seal groove (42), and a left second retaining ring groove (44); The inner ring of the right shoulder (6) is provided with a right first retaining ring groove (39), a right first step seal groove (41), a right second step seal groove (43), and a right second retaining ring groove (45); The inner ring of the left sealing block (26) is provided with a left first inner retaining ring groove (46), a left first inner step seal groove (48), a left second inner step seal groove (50), and a left second inner retaining ring groove (52); The inner ring of the right sealing block (27) is provided with a right first inner retaining ring groove (47), a right first inner step seal groove (49), a right second inner step seal groove (51), and a right second inner retaining ring groove (53); The diameter of the shaft body (2) is ≥ 5% to 50% of the diameter of the left journal (3) and the right journal (4); The diameter of the left shaft shoulder (5) and right shaft shoulder (6) is ≥ 5% to 30% of the diameter of the left shaft foot (7) and right shaft foot (8); The cross-sections of the left axle foot (7) and the right axle foot (8) are in the shape of a runway; The axial section of the oil cavity (11) is a symmetrical cone shape, and the minimum diameter of the shaft body (2) in the middle of the axial section of the oil cavity (11) is at least 1 mm; the cross sections of the left bearing sleeve (12) and the right bearing sleeve (13) are symmetrical stepped, and the small diameter part is interference fit with the outer ring of the left bearing (16) and the right bearing (17) (interference amount 0.02 mm); The left bearing (16) and right bearing (17) are respectively interference-fitted with the left journal (3) and right journal (4) (interference amount 0.02mm); the left bearing sleeve (12) is fitted with the left first retaining ring (18), the left first step seal (20), the left second step seal (22), and the left second retaining ring (24) on the inner side of the large diameter; The right bearing sleeve (13) is fitted with a right first retaining ring (19), a right first step seal (21), a right second step seal (23), and a right second retaining ring (25) on the inner side of its large diameter. The left sealing block (26) is axially pressed against the end face of the sealing assembly composed of the left first retaining ring (18), the left first step seal (20), the left second step seal (22), and the left second retaining ring (24); The right sealing block (27) is axially pressed against the end face of the sealing assembly consisting of the right first retaining ring (19), the right first step seal (21), the right second step seal (23), and the right second retaining ring (25); The inner rings of the left wheel hub (14) and the right wheel hub (15) each have at least three reinforcing ribs evenly distributed. The sealing bolt hole (36) penetrates the wall thickness of the oil cavity (11); The axle (1), axle body (2), left journal (3), right journal (4), left shoulder (5), right shoulder (6), left foot (7), right foot (8), left fastening screw (9), right fastening screw (10), oil chamber (11), left bearing sleeve (12), right bearing sleeve (13), left hub (14), right hub (15), left bearing (16), right bearing (17), left sealing block (26), right sealing block (27), and sealing bolt hole (36) are described. The sealing bolt (37) is made of 304 stainless steel, UNS S2057 duplex stainless steel or 18Ni 300 maraging steel, which are the same materials as the axle. The left first seal (20), right first seal (21), left second seal (22), right second seal (23), left inner first seal (30), right first seal (31), left second seal (32), and right second seal (33) are all sealing components composed of slip rings and O-rings; The sealing gasket of the sealing bolt (37) is made of fluororubber or perfluoroether rubber.

[0031] like Figures 1 to 4As shown, further, the inner hole roundness of the left bearing sleeve (12), right bearing sleeve (13), left sealing block (26), and right sealing block (27) is ≤IT5 grade, coaxiality is ≤0.02mm, inner wall surface roughness Ra≤0.1μm, Rz≤0.5μm, and waviness is ≤0.05μm. When the external water pressure increases, the left sealing block (26) and right sealing block (27) move slightly towards the oil cavity, forcing the lubricating oil pressure to increase synchronously, thereby achieving dynamic pressure balance (loss <0.5Mpa).

[0032] like Figures 1 to 4 As shown, further, the angle between the hole axis of the sealing bolt hole (36) and the normal of the wall surface of the oil cavity (11) is ≤30°.

[0033] like Figures 1 to 3 As shown, the wheel axle (1), left bearing sleeve (12), right bearing sleeve (13), left sealing block (26), and right sealing block (27) are further subjected to WC-17Co cladding, nitriding, and DLC coating treatment (coating thickness 2-5um).

[0034] like Figures 1 to 4 As shown, further, the straightness of the outer wall of the left shoulder (5), the right shoulder (6), the left sealing block (26), and the right sealing block (27) is ≤0.01mm / m, and the coaxiality is ≤0.02mm.

[0035] like Figures 1 to 4 As shown, further, the roughness Ra of the sealing end of the outer wall of the left sealing block (26) and the outer wall of the right sealing block (27) is ≤0.05μm.

[0036] like Figures 1 to 4 As shown, further, the outer wall sealing end roughness Ra≤0.05μm of the left shoulder (5) and right shoulder (6) is Ra≤0.4μm, and the transition area from the sealing end to the non-sealing end is polished with gradient polishing.

[0037] like Figures 1 to 4 As shown, further, the diameter of the left sealing block (26) and the right sealing block (27) / the ratio of the left shoulder (5) and the right shoulder (6) is ≥1:16.

[0038] like Figures 1 to 4 As shown, the inner hole assembly clearance between the left shoulder (5), right shoulder (6) and the left sealing block (26), right sealing block (27) is 0.01mm to 0.03mm.

[0039] like Figures 1 to 4 As shown, the large diameter assembly clearance between the left sealing block (26), the right sealing block (27) and the left bearing sleeve (12), the right bearing sleeve (13) is 0.01 mm to 0.03 mm.

[0040] like Figures 1 to 4 As shown, furthermore, the slip ring materials of the left first slip seal (20), right first slip seal (21), left second slip seal (22), right second slip seal (23), left inner first slip seal (30), right inner first slip seal (31), left inner second slip seal (32), and right inner second slip seal (33) are PTFE filled with copper powder or carbon fiber, and the O-rings are made of perfluoroether rubber. The O-rings are tested according to standard ASTM D395 method B and have a low-temperature compression set of <8% and a water absorption swelling rate of <1% at -40℃.

[0041] like Figures 1 to 4 As shown, the left first seal (20) and the left second seal (22), the right first seal (21) and the right second seal (23), the left inner first seal (30) and the left inner second seal (32), and the right inner first seal (31) and the right inner second seal (33) are all arranged back to back.

[0042] like Figures 1 to 4 As shown, the axial compression ratio (pre-compression amount) of the left first seal (20), right first seal (21), left second seal (22), right second seal (23), left inner first seal (30), right inner first seal (31), left inner second seal (32), and right inner second seal (33) is 10% to 20%.

[0043] like Figures 1 to 4 As shown, the slip rings of the left first slip seal (20), right first slip seal (21), left second slip seal (22), right second slip seal (23), left inner first slip seal (30), right inner first slip seal (31), left inner second slip seal (32), and right inner second slip seal (33) are 2 to 4-lobed split structures (preferably 3-lobed split structures).

[0044] like Figures 1 to 4 As shown, further, the roughness Ra of the slip ring split cut of the left first stator seal (20), right first stator seal (21), left second stator seal (22), right second stator seal (23), left inner first stator seal (30), right inner first stator seal (31), left inner second stator seal (32), and right inner second stator seal (33) is ≤10μm, the internal friction pair is treated with laser micro-pits (pit diameter 50μm, pit center distance 8mm to 24mm), the external contact surface is mirror polished with Ra≤0.04μm, and the non-contact surface with Ra≤1.64μm.

[0045] like Figures 1 to 4As shown, further, the depths of the left first step seal groove (40), left second step seal groove (42), right first step seal groove (41), right second step seal groove (43), left first inner step seal groove (48), left second inner step seal groove (50), right first inner step seal groove (49), and right second inner step seal groove (51) are 0.1 mm to 0.3 mm greater than the axial thickness of the corresponding step seal slip ring, and the radial clearance is ≤0.1 mm.

[0046] like Figures 1 to 4 As shown, further, the sealing surface roughness Ra≤0.4μm and the non-sealing surface roughness Ra≤1.6μm of the left first sealing groove (40), left second sealing groove (42), right first sealing groove (41), right second sealing groove (43), left first inner side sealing groove (48), left second inner side sealing groove (50), right first inner side sealing groove (49), and right second inner side sealing groove (51) are respectively. The inlet chamfer is 20° to 30° (R0.2 to 0.5mm) and the root fillet is R0.1mm to 0.3mm.

[0047] like Figures 1 to 4 As shown, the materials of the left first retaining ring (18), right first retaining ring (19), left second retaining ring (24), right second retaining ring (25), left first inner retaining ring (28), right first inner retaining ring (29), left second inner retaining ring (34), and right second inner retaining ring (35) are wear-resistant polyoxymethylene, or polytetrafluoroethylene filled with bronze powder and glass fiber, or polytetrafluoroethylene filled with bronze powder and carbon fiber, or polyether ether ketone filled with glass fiber, or polyether ether ketone filled with carbon fiber, with a hardness ≥ HRC50.

[0048] like Figures 1 to 4 As shown, further, the width of the left first retaining ring (18), right first retaining ring (19), left second retaining ring (24), right second retaining ring (25), left first inner retaining ring (28), right first inner retaining ring (29), left second inner retaining ring (34), and right second inner retaining ring (35) is not less than 1.2 times the thickness of its adjacent step seal slip ring, and the width tolerance is ±0.05mm, and the gap with the corresponding retaining ring groove is ≤0.1mm (H8 / f8 fit).

[0049] like Figures 1 to 4As shown, further, the width of the left first retaining ring groove (38), the left second retaining ring groove (44), the right first retaining ring groove (39), the right second retaining ring groove (45), the left first inner retaining ring groove (46), the left second inner retaining ring groove (52), the right first inner retaining ring groove (47), and the right second inner retaining ring groove (53) is 0.2 mm to 0.5 mm larger than the corresponding retaining ring, and the depth is consistent with the thickness of the corresponding retaining ring (depth tolerance ±0.02 mm).

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An underwater robot walking wheel, characterized by comprising a wheel axle (1), axle body (2), left journal (3), right journal (4), left shoulder (5), right shoulder (6), left foot (7), right foot (8), left fastening screw (9), right fastening screw (10), oil cavity (11), left bearing sleeve (12), right bearing sleeve (13), left hub (14), right hub (15), left bearing (16), right bearing (17), left first retaining ring (18), right first retaining ring (19), left first seal (20), right first seal (21). 21) Left second seal (22), right second seal (23), left second retaining ring (24), right second retaining ring (25), left sealing block (26), right sealing block (27), left first inner retaining ring (28), right first inner retaining ring (29), left inner first seal (30), right inner first seal (31), left inner second seal (32), right inner second seal (33), left second inner retaining ring (34), right second inner retaining ring (35), sealing bolt hole (36), sealing bolt (37), forming a coaxial symmetrical structure; The inner ring of the left shoulder (5) is provided with a left first retaining ring groove (38), a left first step seal groove (40), a left second step seal groove (42), and a left second retaining ring groove (44); The inner ring of the right shoulder (6) is provided with a right first retaining ring groove (39), a right first step seal groove (41), a right second step seal groove (43), and a right second retaining ring groove (45); The inner ring of the left sealing block (26) is provided with a left first inner retaining ring groove (46), a left first inner step seal groove (48), a left second inner step seal groove (50), and a left second inner retaining ring groove (52); The inner ring of the right sealing block (27) is provided with a right first inner retaining ring groove (47), a right first inner step seal groove (49), a right second inner step seal groove (51), and a right second inner retaining ring groove (53); The diameter of the shaft body (2) is ≥ 5% to 50% of the diameter of the left journal (3) and the right journal (4); The diameter of the left shaft shoulder (5) and right shaft shoulder (6) is ≥ 5% to 30% of the diameter of the left shaft foot (7) and right shaft foot (8); The cross-sections of the left axle foot (7) and the right axle foot (8) are in the shape of a runway; The axial section of the oil cavity (11) is a symmetrical cone shape, and the minimum diameter of the shaft body (2) in the middle of the axial section of the oil cavity (11) is at least 1 mm; the cross sections of the left bearing sleeve (12) and the right bearing sleeve (13) are symmetrical stepped, and the small diameter part is interference fit with the outer ring of the left bearing (16) and the right bearing (17); The left bearing (16) and the right bearing (17) are respectively interference-fitted with the left journal (3) and the right journal (4); The left bearing sleeve (12) is fitted with a left first retaining ring (18), a left first step seal (20), a left second step seal (22), and a left second retaining ring (24) on the inner side of its large diameter. The right bearing sleeve (13) is fitted with a right first retaining ring (19), a right first step seal (21), a right second step seal (23), and a right second retaining ring (25) on the inner side of its large diameter. The left sealing block (26) is installed inside the left first retaining ring (18), the left first step seal (20), the left second step seal (22), and the left second retaining ring (24); The right sealing block (27) is installed inside the right first retaining ring (19), the right first step seal (21), the right second step seal (23), and the right second retaining ring (25); The inner rings of the left wheel hub (14) and the right wheel hub (15) each have at least three reinforcing ribs evenly distributed. The sealing bolt hole (36) penetrates the wall thickness of the oil cavity (11); The axle (1), axle body (2), left journal (3), right journal (4), left shoulder (5), right shoulder (6), left foot (7), right foot (8), left fastening screw (9), right fastening screw (10), oil chamber (11), left bearing sleeve (12), right bearing sleeve (13), left hub (14), right hub (15), left bearing (16), right bearing (17), left sealing block (26), right sealing block (27), and sealing bolt hole (36) are described. The sealing bolt (37) is made of the same material as the axle: 304 stainless steel, UNS S2057 duplex stainless steel, or 18Ni 300 maraging steel. The left first seal (20), right first seal (21), left second seal (22), right second seal (23), left inner first seal (30), right first seal (31), left second seal (32), and right second seal (33) are all sealing components composed of slip rings and O-rings; The sealing gasket of the sealing bolt (37) is made of fluororubber or perfluoroether rubber.

2. The underwater robot's walking wheel according to claim 1, characterized in that, The inner hole roundness of the left bearing sleeve (12), right bearing sleeve (13), left sealing block (26), and right sealing block (27) is ≤IT5 grade, coaxiality is ≤0.02mm, inner wall surface roughness Ra≤0.1μm, Rz≤0.5μm, and waviness is ≤0.05μm.

3. The underwater robot's walking wheel according to claim 1, characterized in that, The angle between the axis of the sealing bolt hole (36) and the normal of the wall surface of the oil cavity (11) is ≤30°.

4. The underwater robot's walking wheel according to claim 1, characterized in that, The wheel axle (1), left bearing sleeve (12), right bearing sleeve (13), left sealing block (26), and right sealing block (27) are subjected to WC-17Co cladding, nitriding, and DLC coating treatment (coating thickness 2-5um).

5. The underwater robot's walking wheel according to claim 1, characterized in that, The straightness of the outer walls of the left shoulder (5), right shoulder (6), left sealing block (26), and right sealing block (27) is ≤0.01mm / m, and the coaxiality is ≤0.02mm.

6. The underwater robot's walking wheel according to claim 1, characterized in that, The roughness Ra of the sealing end of the outer wall of the left sealing block (26) and the outer wall of the right sealing block (27) is ≤0.05μm.

7. The underwater robot's walking wheel according to claim 1, characterized in that, The outer wall sealing end roughness Ra≤0.05μm and the non-sealing end roughness Ra≤0.4μm of the left shoulder (5) and right shoulder (6) are respectively subjected to gradient polishing.

8. The underwater robot's walking wheel according to claim 1, characterized in that, The bore diameter of the left sealing block (26) and the right sealing block (27) / the ratio of the left shoulder (5) and the right shoulder (6) is ≥1:

16.

9. The underwater robot's walking wheel according to claim 1, characterized in that, The assembly clearance between the left shoulder (5), right shoulder (6) and the inner hole of the left sealing block (26), right sealing block (27) is 0.01mm to 0.03mm.

10. The underwater robot's walking wheel according to claim 1, characterized in that, The large-diameter assembly clearance between the left sealing block (26), the right sealing block (27) and the left bearing sleeve (12), the right bearing sleeve (13) is 0.01mm to 0.03mm.

11. The underwater robot's walking wheel according to claim 1, characterized in that, The slip rings of the left first slip seal (20), right first slip seal (21), left second slip seal (22), right second slip seal (23), left inner first slip seal (30), right inner first slip seal (31), left inner second slip seal (32), and right inner second slip seal (33) are made of PTFE filled with copper powder or carbon fiber. The O-rings are made of perfluoroether rubber. The O-rings are tested according to standard ASTM D395 method B and have a low-temperature compression set of <8% and a water absorption swelling rate of <1% at -40℃.

12. The underwater robot's walking wheel according to claim 1, characterized in that, The left first seal (20) and left second seal (22), right first seal (21) and right second seal (23), left inner first seal (30) and left inner second seal (32), and right inner first seal (31) and right inner second seal (33) are all arranged back to back.

13. The underwater robot's walking wheel according to claim 1, characterized in that, The axial compression ratio (pre-compression amount) of the left first seal (20), right first seal (21), left second seal (22), right second seal (23), left inner first seal (30), right inner first seal (31), left inner second seal (32), and right inner second seal (33) is 10% to 20%.

14. The underwater robot's walking wheel according to claim 1, characterized in that, The slip rings of the left first stator (20), right first stator (21), left second stator (22), right second stator (23), left inner first stator (30), right inner first stator (31), left inner second stator (32), and right inner second stator (33) are 2 to 4-lobed split structures.

15. The underwater robot's walking wheel according to claim 1, characterized in that, The roughness of the slip ring split cut of the left first slip seal (20), right first slip seal (21), left second slip seal (22), right second slip seal (23), left inner first slip seal (30), right inner first slip seal (31), left inner second slip seal (32), and right inner second slip seal (33) is Ra≤10μm. The internal friction pair is treated with laser micro-pits (pit diameter 50μm, pit center distance 8mm to 24mm). The external contact surface is mirror-polished with Ra≤0.04μm and the non-contact surface with Ra≤1.64μm.

16. The underwater robot's walking wheel according to claim 1, characterized in that, The depths of the left first step seal groove (40), left second step seal groove (42), right first step seal groove (41), right second step seal groove (43), left first inner step seal groove (48), left second inner step seal groove (50), right first inner step seal groove (49), and right second inner step seal groove (51) are 0.1 mm to 0.3 mm greater than the axial thickness of the corresponding step seal slip ring, and the radial clearance is ≤0.1 mm.

17. The underwater robot's walking wheel according to claim 1, characterized in that, The sealing surface roughness Ra≤0.4μm and the non-sealing surface roughness Ra≤1.6μm of the left first sealing groove (40), left second sealing groove (42), right first sealing groove (41), right second sealing groove (43), left first inner sealing groove (48), left second inner sealing groove (50), right first inner sealing groove (49), and right second inner sealing groove (51) are respectively. The inlet chamfer is 20° to 30° (R0.2 to 0.5mm) and the root fillet is R0.1mm to 0.3mm.

18. The underwater robot's walking wheel according to claim 1, characterized in that, The materials of the left first retaining ring (18), right first retaining ring (19), left second retaining ring (24), right second retaining ring (25), left first inner retaining ring (28), right first inner retaining ring (29), left second inner retaining ring (34), and right second inner retaining ring (35) are wear-resistant polyoxymethylene, or polytetrafluoroethylene filled with bronze powder and glass fiber, or polytetrafluoroethylene filled with bronze powder and carbon fiber, or polyether ether ketone filled with glass fiber, or polyether ether ketone filled with carbon fiber, with a hardness ≥ HRC50.

19. The underwater robot's walking wheel according to claim 1, characterized in that, The width of the left first retaining ring (18), right first retaining ring (19), left second retaining ring (24), right second retaining ring (25), left first inner retaining ring (28), right first inner retaining ring (29), left second inner retaining ring (34), and right second inner retaining ring (35) is not less than 1.2 times the thickness of its adjacent step seal slip ring, and the width tolerance is ±0.05mm, and the gap with the corresponding retaining ring groove is ≤0.1mm (H8 / f8 fit).

20. The underwater robot's walking wheel according to claim 1, characterized in that, The width of the left first retaining ring groove (38), left second retaining ring groove (44), right first retaining ring groove (39), right second retaining ring groove (45), left first inner retaining ring groove (46), left second inner retaining ring groove (52), right first inner retaining ring groove (47), and right second inner retaining ring groove (53) is 0.2 mm to 0.5 mm larger than the corresponding retaining ring, and the depth is consistent with the thickness of the corresponding retaining ring (depth tolerance ±0.02 mm).

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