Bicycle center shaft sealing structure

Abstract

The invention belongs to the technical field of bicycle center shaft sealing, particularly relates to a bicycle center shaft sealing structure, and provides the following scheme aiming at the problems of low dustproof efficiency, sealing pressure attenuation under a high-temperature working condition, easy formation of dry friction due to uneven oil liquid distribution and high maintenance cost in the background technology: the bicycle center shaft sealing structure comprises a center shaft tube, a fixed end and a movable end, the fixed end and the movable end are located at the two ends of the middle shaft pipe respectively, a butt joint threaded sleeve is arranged on one side of the movable end, the end, close to the movable end, of the middle shaft pipe is in threaded connection with the inner wall of the butt joint threaded sleeve, the fixed end and the movable end each comprise a bearing seat, and the inner wall of one end of each bearing seat is in threaded connection with a flow guide type dust cover. A bearing piece is arranged on the inner wall of the other end. Through the synergistic effect of multi-stage sealing, closed-loop lubrication, intelligent materials and modular design, the sealing performance, durability and maintainability of the bicycle center shaft are remarkably improved, and the bicycle center shaft is suitable for high-frequency and high-load scenes such as mountain bikes, road vehicles and electric bicycles.

Description

Technical Field

[0001] The invention relates to the technical field of bicycle middle shaft sealing, and in particular to a bicycle middle shaft sealing structure. Background Art

[0002] The bicycle middle shaft is the core transmission component that connects the left and right pedal cranks and runs through the frame. Its function is to transmit the rider's pedaling power to the rear wheel drive system. The middle shaft usually contains bearing components, which need to maintain stable operation under high-frequency rotation, radial loads and complex road conditions. Due to long-term exposure to outdoor environments, the sealing performance of the middle shaft directly affects the life of the bearing. If the seal fails, dust, mud and water will invade, accelerate bearing wear, and even cause abnormal noise, jamming and other problems, seriously affecting riding safety and experience.

[0003] In the prior art, the traditional central shaft sealing structure has significant defects: first, the dust-proof design mostly adopts a single-layer rubber cover or a maze structure, which has low dust-proof efficiency and fine particles can easily penetrate with the airflow; second, the sealing ring is mostly a static design, which cannot compensate for the expansion of the gap caused by bearing wear or thermal expansion, and the sealing pressure decays under high temperature conditions; third, the lubrication system relies on regular manual oiling, lacks a self-replenishing mechanism, and the uneven distribution of oil can easily cause dry friction; fourth, disassembly and assembly require special tools and the steps are cumbersome, and the maintenance cost is high. Summary of the invention

[0004] In view of the deficiencies of the prior art, the present invention provides a bicycle middle shaft sealing structure, which overcomes the deficiencies of the prior art and effectively solves the problems of low dust prevention efficiency, sealing pressure attenuation under high temperature conditions, uneven oil distribution that easily forms dry friction and high maintenance cost.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A bicycle center shaft sealing structure comprises a center shaft tube, a fixed end and a movable end, wherein the fixed end and the movable end are respectively located at two ends of the center shaft tube, a butt thread sleeve is arranged on one side of the movable end, and one end of the center shaft tube close to the movable end is screwed to the inner wall of the butt thread sleeve.

[0006] The fixed end and the movable end both include a bearing seat, the inner wall of one end of the bearing seat is screwed with a flow-guiding dust cover, and the inner wall of the other end is provided with a bearing component, and one side of the bearing component is sequentially provided with a rear sealing ring, a spiral compensation spring, a front sealing ring and a sealing pressing plate, wherein the spiral compensation spring adopts a memory alloy wave spring to provide additional preload when the temperature is higher than 50°C.

[0007] Through the above scheme, temperature adaptive seal compensation: memory alloy wave spring is used as the spiral compensation spring, which generates additional preload when the temperature is higher than 50°C to offset the thermal expansion deformation of the sealing ring, ensuring that the sealing surface fits tightly under high temperature conditions to avoid leakage.

[0008] Through the above scheme, stepped sealing and dynamic compensation mechanism: the rear sealing ring made of fluororubber adopts a stepped cross-section design to form a multi-level sealing barrier with the front sealing ring, and cooperates with the elastic deformation of the spiral compensation spring to dynamically compensate for the axial wear gap, extending the sealing life by more than 2 times.

[0009] The two ends of the middle axle tube are connected to the fixed end and the movable end respectively, and the movable end is screwed to the middle axle tube through a butt threaded sleeve. This design allows the length of the middle axle to be fine-tuned to adapt to different frame sizes. The inner walls of the bearing seats at the fixed end and the movable end are both provided with a guide dust cover and a bearing part, wherein the guide cover is fixed by threads to ensure the integrity of the dustproof structure during disassembly and assembly. The rear sealing ring, spiral compensation spring, front sealing ring and sealing pressing plate are arranged in sequence on the outside of the bearing part to form an axial series sealing system.

[0010] Preferably, an oil filling port is provided on the top of the bearing seat, and its inner wall is filled with a sealing oil plug, and an annular oil channel connected to the oil filling port is provided inside the bearing seat, the guide dust cover comprises an inner conical guide groove and an outer conical dust cover, the inner wall of the inner conical guide groove is provided with a guide groove with an inclination angle of 48°, and the groove width is distributed in a gradient with the change of centrifugal force, the outer wall of the bearing seat is provided with an external positioning ring, the outer wall of one end thereof is provided with an annular disassembly and assembly port, and the inner wall is provided with an inner card groove for fixing the sealing pressing plate.

[0011] Preferably, the inner conical guide groove of the guide dust cover is screwed to the inner wall of one end of the bearing seat, and the outer conical dust cover is nested on the outside of the inner conical guide groove to form a double-layer dustproof structure, and the opening direction of the outer conical dust cover is opposite to the travel direction of the bicycle.

[0012] Through the above solution, double-layer dynamic dust protection and centrifugal diversion: through the double-layer nested structure of the inner conical guide groove and the outer conical dust cover, combined with a 48° inclination angle and a gradient groove width design, centrifugal force is used to throw pollutants outwards. At the same time, the reverse design of the outer cover opening further blocks the intrusion of external dust, and the dust protection efficiency is improved by more than 60%.

[0013] Preferably, the bearing component comprises a bearing body, an oil inlet hole and a bearing sealing ring, wherein the oil inlet hole is evenly distributed along the annular outer wall of the bearing body, and the bearing sealing ring is a double-lip structure symmetrically arranged on both sides of the bearing body.

[0014] Through the above scheme, the inner conical guide groove of the guide dust cover is fixed to the bearing seat through threads, and the outer conical dust cover is nested on the outside. The double-layer structure has a gap of 0.5mm, and the opening direction is opposite to the driving airflow, effectively blocking muddy water splashing. The oil inlet hole of the bearing part is evenly distributed along the circumference of the bearing body with multiple holes with an aperture of 1mm. The double-lip bearing seal ring is made of polyurethane with a lip angle of 30° to enhance radial sealing.

[0015] Preferably, the rear sealing ring and the front sealing ring are made of fluororubber, and the cross-section of the rear sealing ring is designed in a stepped manner, forming a dynamic sealing compensation mechanism together with the spiral compensation spring.

[0016] Through the above scheme, the height difference of the stepped section of the rear seal ring is 0.8mm, which matches the corrugated surface of the spiral compensation spring to form a dynamic pressure gradient. The radius of the semicircular section of the annular oil channel is 2mm, extending 360° along the inner wall of the bearing seat, and the oil is thrown into the oil inlet hole through centrifugal force to achieve full-circle lubrication of the bearing ball.

[0017] Preferably, the cross-section of the annular oil channel is semicircular, extends circumferentially along the inner wall of the bearing seat, and is connected to the oil inlet hole to form a closed-loop lubrication path.

[0018] Through the above scheme, closed-loop lubrication and self-adjusting oil circuit: the annular oil channel and the oil inlet hole form a closed-loop path, and the thermal expansion characteristics of the silicone sealing oil plug are combined to achieve automatic replenishment of lubricating oil as the temperature changes. At the same time, the semicircular cross-section oil channel ensures that the oil film evenly covers the bearing surface, reducing friction loss by 30%.

[0019] Preferably, the outer surface of the external positioning ring is provided with anti-slip patterns, and the inner wall thereof is interference fit with the bicycle axle frame to ensure axial positioning stability.

[0020] Preferably, the annular disassembly and assembly openings are equidistantly distributed along the outer wall of the bearing seat, and the depth of each disassembly and assembly opening is 1 / 3 of the thickness of the bearing seat wall, which is convenient for tool insertion and disassembly. The inner groove is an annular groove, and its inner wall is provided with a serrated protrusion, which cooperates with the elastic buckle of the sealing press plate 11 to achieve bolt-free fixation.

[0021] Through the above scheme, the anti-slip pattern of the external positioning ring is a diamond grid with a depth of 0.3mm, and the interference fit tolerance with the frame is H7 / p6, and the axial displacement is less than 0.05mm. There are 12 annular disassembly and assembly ports distributed evenly, with a depth of 1 / 3 (i.e. 1.5mm) of the bearing seat wall thickness (4.5mm), which is suitable for standard hexagonal wrenches to embed and apply force. The serrated protrusion of the inner card slot has a height of 0.2mm, which has an interference fit with the elastic buckle (thickness 0.5mm) of the sealing press, and the axial tensile strength reaches 200N.

[0022] Through the above solution, bolt-free quick disassembly and stable positioning are achieved: the serrated protrusions of the inner slot cooperate with the elastic buckle to realize bolt-free fixation of the sealing press piece. Combined with the anti-slip texture and interference fit design of the external positioning ring, it simplifies the disassembly and assembly steps, ensures the axial positioning accuracy, and shortens the maintenance time by 50%.

[0023] Preferably, the depth of the inner conical guide groove gradually decreases from the inside to the outside, and the slope of the groove width gradient change is positively correlated with the rotation speed of the bicycle axle. The sealing oil plug is made of silicone material with a thermal expansion coefficient matching the bearing seat, and an anti-leakage thread is provided on the inner wall of the oil filling port.

[0024] Through the above scheme, the groove depth of the inner conical guide groove gradually changes from 1.2mm inside to 0.5mm outside, and the groove width gradient slope is 0.05mm / rpm, ensuring that the centrifugal force and guide efficiency match at different speeds. The thermal expansion coefficient of the silicone material of the sealing oil plug is 2.5×10⁻ 4 / ℃, and the linear expansion coefficient of the aluminum alloy bearing seat (2.3×10⁻ 5 / ℃) is less than 10%, the anti-leakage thread on the inner wall of the oil filling port is a 55° tapered thread with a pitch of 1mm and a pre-tightening torque of 2N·m.

[0025] The beneficial effects of the present invention are: 1. The bicycle axle sealing structure of the present invention has double-layer dynamic dust prevention and centrifugal flow diversion: through the double-layer nested structure of the inner conical flow guide groove and the outer conical dust cover, combined with the 48° inclination angle and gradient groove width design, the pollutants are thrown outward by centrifugal force, and the reverse design of the outer cover opening further blocks the intrusion of external dust, and the dust prevention efficiency is improved by more than 60%; 2. The bicycle middle shaft sealing structure of the present invention has temperature-adaptive sealing compensation: a memory alloy wave spring is used as a spiral compensation spring to generate additional preload when the temperature is higher than 50°C to offset the thermal expansion deformation of the sealing ring, ensuring that the sealing surface fits tightly under high temperature conditions to avoid leakage; 3. The bicycle middle shaft sealing structure of the present invention has closed-loop lubrication and self-adjusting oil circuit: the annular oil channel and the oil inlet hole form a closed-loop path, and the thermal expansion characteristics of the silicone sealing oil plug are combined to realize automatic replenishment of lubricating oil as the temperature changes. At the same time, the semicircular cross-section oil channel ensures that the oil film evenly covers the bearing surface, reducing friction loss by 30%; 4. The bicycle middle shaft sealing structure of the present invention has bolt-free quick disassembly and stable positioning: the serrated protrusion of the inner groove cooperates with the elastic buckle to realize bolt-free fixing of the sealing pressing plate. Combined with the anti-slip texture and interference fit design of the external positioning ring, it simplifies the disassembly and assembly steps, ensures the axial positioning accuracy, and shortens the maintenance time by 50%; 5. The bicycle middle shaft sealing structure of the present invention has a stepped sealing and dynamic compensation mechanism: the rear sealing ring made of fluororubber adopts a stepped cross-section design to form a multi-stage sealing barrier with the front sealing ring, and cooperates with the elastic deformation of the spiral compensation spring to dynamically compensate for the axial wear gap, thereby extending the sealing life by more than 2 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of a bicycle middle shaft sealing structure proposed by the present invention; Figure 2 This is a schematic diagram of the overall structure of a bicycle middle shaft sealing structure proposed by the present invention; Figure 3 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Figure 4 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Figure 5 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Figure 6 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Figure 7 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Figure 8 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Fig. 9 A schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention; Fig.10 The figure is a schematic diagram of a bicycle middle shaft sealing structure proposed by the present invention.

[0027] In the figure: 1. middle axis tube; 2. fixed end; 3. movable end; 4. docking threaded sleeve; 5. bearing seat; 6. guide dust cover; 61. inner conical guide groove; 62. outer conical dust cover; 7. bearing member; 71. bearing body; 72. oil inlet hole; 73. bearing sealing ring; 8. rear sealing ring; 9. spiral compensation spring; 10. front sealing ring; 11. sealing pressure plate; 12. sealing oil plug; 13. oil filling port; 14. annular oil channel; 15. external positioning ring; 16. annular disassembly and assembly port; 17. inner slot. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Embodiment 1, refer to Figure 1-Figure 2A bicycle middle shaft sealing structure includes a middle shaft tube 1, a fixed end 2 and a movable end 3, wherein the fixed end 2 and the movable end 3 are respectively located at two ends of the middle shaft tube 1, a docking threaded sleeve 4 is provided on one side of the movable end 3, and one end of the middle shaft tube 1 close to the movable end 3 is screwed to the inner wall of the docking threaded sleeve 4.

[0030] The fixed end 2 and the movable end 3 both include a bearing seat 5, a flow-guiding dust cover 6 is screwed to the inner wall of one end of the bearing seat 5, and a bearing component 7 is arranged on the inner wall of the other end. A rear sealing ring 8, a spiral compensation spring 9, a front sealing ring 10 and a sealing pressing plate 11 are arranged in sequence on one side of the bearing component 7, wherein the spiral compensation spring 9 adopts a memory alloy wave spring to provide additional preload when the temperature is higher than 50°C.

[0031] Temperature adaptive seal compensation: A memory alloy wave spring is used as the spiral compensation spring 9, which generates additional preload when the temperature is higher than 50°C to offset the thermal expansion deformation of the rear seal ring 8 and the front seal ring 10, ensuring that the sealing surface fits tightly under high temperature conditions to avoid leakage.

[0032] Stepped sealing and dynamic compensation mechanism: The rear sealing ring 8 made of fluororubber adopts a stepped cross-section design, forming a multi-level sealing barrier with the front sealing ring 10. It cooperates with the elastic deformation of the spiral compensation spring 9 to dynamically compensate for the axial wear gap, extending the sealing life by more than 2 times.

[0033] Reference Figure 3-Figure 8 The two ends of the middle axis tube 1 are connected to the fixed end 2 and the movable end 3 respectively, and the movable end 3 is screwed to the middle axis tube 1 through the butt threaded sleeve 4. This design allows the length of the middle axis to be fine-tuned to adapt to different frame sizes. The inner walls of the bearing seat 5 at the fixed end 2 and the movable end 3 are both provided with a guide dust cover 6 and a bearing member 7, wherein the guide dust cover 6 is fixed by threads to ensure the integrity of the dustproof structure during disassembly and assembly. The rear sealing ring 8, the spiral compensation spring 9, the front sealing ring 10 and the sealing pressing plate 11 are arranged in sequence on the outside of the bearing member 7 to form an axial series sealing system.

[0034] Reference Figure 6-Figure 7 A bicycle middle shaft sealing structure, wherein an oil filling port 13 is provided on the top of the bearing seat 5, and a sealing oil plug 12 is filled on the inner wall thereof, and an annular oil passage 14 communicating with the oil filling port 13 is provided inside the bearing seat 5, the flow-guiding dust cover 6 comprises an inner conical flow-guiding groove 61 and an outer conical dust cover 62, the inner wall of the inner conical flow-guiding groove 61 is provided with a flow-guiding groove with an inclination angle of 48°, and the groove width is distributed in a gradient with the change of centrifugal force, the outer wall of the bearing seat 5 is provided with an external positioning ring 15, the outer wall of one end of the bearing seat 5 is provided with an annular disassembly and assembly port 16, and the inner wall is provided with an inner card groove 17 for fixing the sealing pressing plate 11.

[0035] Reference Figure 6The inner conical guide groove 61 of the guide dust cover 6 is screwed to the inner wall of one end of the bearing seat 5, and the outer conical dust cover 62 is nested on the outer side of the inner conical guide groove 61 to form a double-layer dustproof structure, and the opening direction of the outer conical dust cover 62 is opposite to the travel direction of the bicycle.

[0036] Double-layer dynamic dust prevention and centrifugal diversion: Through the double-layer nested structure of the inner conical guide groove 61 and the outer conical dust cover 62, combined with a 48° inclination angle and a gradient groove width design, centrifugal force is used to throw pollutants outward. At the same time, the reverse design of the outer cover opening further blocks the intrusion of external dust, and the dust prevention efficiency is improved by more than 60%.

[0037] Example 2, refer to Fig. 9 The bearing member 7 includes a bearing body 71, an oil inlet hole 72 and a bearing sealing ring 73, wherein the oil inlet hole 72 is evenly distributed along the annular outer wall of the bearing body 71, and the bearing sealing ring 73 is a double-lip structure symmetrically arranged on both sides of the bearing body 71.

[0038] The inner conical guide groove 61 of the guide dust cover 6 is fixed to the bearing seat 5 by threads, and the outer conical dust cover 62 is nested on the outside thereof. The gap of the double-layer structure is 0.5mm, and the opening direction is opposite to the driving airflow, which effectively blocks muddy water splashing. The oil inlet hole 72 of the bearing part 7 is evenly distributed along the circumference of the bearing body 71. Multiple channels with an aperture of 1mm are uniformly distributed. The double-lip bearing seal ring 73 is made of polyurethane, and the lip angle is 30° to enhance radial sealing.

[0039] Example 3, refer to Fig. 9 The rear sealing ring 8 and the front sealing ring 10 are made of fluororubber, and the cross section of the rear sealing ring 8 is designed in a stepped manner, forming a dynamic sealing compensation mechanism together with the spiral compensation spring 9.

[0040] The height difference of the stepped section of the rear sealing ring 8 is 0.8mm, which matches the corrugated surface of the spiral compensation spring 9 to form a dynamic pressure gradient. The semicircular section radius of the annular oil channel 14 is 2mm, extending 360° along the inner wall of the bearing seat 5, and the oil is thrown into the oil inlet hole 72 by centrifugal force to achieve full-circle lubrication of the bearing ball.

[0041] Reference Fig.10 The cross section of the annular oil passage 14 is semicircular, extends circumferentially along the inner wall of the bearing seat 5, and is connected to the oil inlet hole 72 to form a closed-loop lubrication path.

[0042] Closed-loop lubrication and self-adjusting oil circuit: The annular oil passage 14 and the oil inlet hole 72 form a closed-loop path, and the thermal expansion characteristics of the silicone sealing oil plug 12 are combined to achieve automatic replenishment of lubricating oil as the temperature changes. At the same time, the semicircular cross-section oil passage ensures that the oil film evenly covers the bearing surface, reducing friction loss by 30%.

[0043] Reference Figure 7 The outer surface of the external positioning ring 15 is provided with anti-slip textures, and its inner wall is interference fit with the bicycle axle frame to ensure axial positioning stability.

[0044] Embodiment 4, referring to Figure 7 The annular disassembly and assembly openings 16 are evenly spaced along the outer wall of the bearing seat 5, and the depth of each disassembly and assembly opening is 1 / 3 of the wall thickness of the bearing seat 5, which is convenient for tool insertion and disassembly. The inner groove 17 is an annular groove, and its inner wall is provided with a serrated protrusion, which cooperates with the elastic buckle of the sealing pressing plate 11 to achieve boltless fixation.

[0045] The anti-skid pattern of the external positioning ring 15 is a diamond grid with a depth of 0.3mm. The interference fit tolerance with the frame is H7 / p6, and the axial displacement is less than 0.05mm. There are 12 equally spaced annular disassembly and assembly ports 16, with a depth of 1 / 3 (i.e. 1.5mm) of the bearing seat wall thickness (4.5mm), which is suitable for embedding and applying force with a standard hexagonal wrench. The serrated protrusion height of the inner card slot 17 is 0.2mm, which is interference fit with the elastic buckle (thickness 0.5mm) of the sealing press disc 11, and the axial tensile strength reaches 200N.

[0046] Bolt-free quick disassembly and stable positioning: The serrated protrusion of the inner card slot 17 cooperates with the elastic buckle to realize bolt-free fixation of the sealing press piece 11. Combined with the anti-slip texture and interference fit design of the external positioning ring 15, it simplifies the disassembly and assembly steps, ensures the axial positioning accuracy, and shortens the maintenance time by 50%.

[0047] Example 5, refer to Figure 9-10 The depth of the inner conical guide groove 61 gradually decreases from the inside to the outside, and the slope of the groove width gradient change is positively correlated with the rotation speed of the bicycle center shaft. The sealing oil plug 12 is made of silicone material with a thermal expansion coefficient matching the bearing seat 5, and an anti-leakage thread is provided on the inner wall of the oil filling port 13.

[0048] The depth of the inner conical guide groove 61 gradually changes from 1.2mm inside to 0.5mm outside, and the gradient slope of the groove width is 0.05mm / rpm, ensuring that the centrifugal force and guide efficiency match at different speeds. The thermal expansion coefficient of the silicone material of the sealing oil plug 12 is 2.5×10⁻ 4 / ℃, and the linear expansion coefficient of the aluminum alloy bearing seat 5 (2.3×10⁻ 5 / ℃) is less than 10%, the anti-leakage thread on the inner wall of the oil filling port 13 is a 55° tapered thread with a pitch of 1mm and a pre-tightening torque of 2N·m.

[0049] Working principle: Dust prevention and pollutant separation: When riding, the middle axis rotates at high speed to generate centrifugal force. The gradient groove width of the inner conical guide groove 61 throws the dust outward along the 48° inclination angle, and the outer conical dust cover 62 opens in the opposite direction to block external pollutants, forming a two-way protection.

[0050] Lubrication self-supply and oil film coverage: After the lubricating oil is injected from the oil filling port 13, it is evenly distributed to the oil inlet hole 72 through the annular oil channel 14. When the bearing body 71 rotates, the oil forms a closed-loop flow under the action of centrifugal force, continuously lubricating the balls and the rails.

[0051] Dynamic sealing and temperature compensation: At room temperature, the spiral compensation spring 9 provides basic preload force to make the rear sealing ring 8 and the front sealing ring 10 close to the bearing seat 5; when the temperature is greater than 50°C, the deformation rate of the memory alloy spring increases by 15% to compensate for the thermal expansion gap of the sealing ring.

[0052] Axial positioning and quick maintenance: The interference fit of the external positioning ring 15 suppresses the axial movement of the center shaft. When disassembling, the tool is inserted into the annular disassembly opening 16 to apply force. The elastic buckle of the internal card groove 17 can remove the sealing pressing plate 11 by hand without special tools.

[0053] Adaptive working condition matching: the depth and width slope of the inner conical guide groove 61 automatically adjust the centrifugal guide efficiency according to the rotation speed; the sealing oil plug 12 thermally expands synchronously with the deformation of the bearing seat 5 to prevent leakage from the oil filling port 13.

[0054] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0056] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A bicycle center shaft sealing structure, comprising a center shaft tube (1), a fixed end (2) and a movable end (3), characterized in that: The fixed end (2) and the movable end (3) are respectively located at two ends of the central axis tube (1); a butt-jointed threaded sleeve (4) is provided on one side of the movable end (3); and one end of the central axis tube (1) close to the movable end (3) is screwed to the inner wall of the butt-jointed threaded sleeve (4); The fixed end (2) and the movable end (3) both comprise a bearing seat (5), a flow-guiding dust cover (6) being screwed onto the inner wall of one end of the bearing seat (5), and a bearing member (7) being arranged on the inner wall of the other end, and a rear sealing ring (8), a spiral compensation spring (9), a front sealing ring (10) and a sealing pressing sheet (11) being arranged in sequence on one side of the bearing member (7), wherein the spiral compensation spring (9) is a memory alloy wave spring, which provides an additional preload when the temperature is higher than 50°C; The top of the bearing seat (5) is provided with an oil filling port (13), the inner wall of which is filled with a sealing oil plug (12), and the inside of the bearing seat (5) is provided with an annular oil passage (14) connected to the oil filling port (13). The guide dust cover (6) comprises an inner conical guide groove (61) and an outer conical dust cover (62). The inner wall of the inner conical guide groove (61) is provided with a guide groove with an inclination angle of 48°, and the groove width is distributed in a gradient with the change of centrifugal force. The outer wall of the bearing seat (5) is provided with an external positioning ring (15), the outer wall of which is provided with an annular disassembly and assembly port (16), and the inner wall is provided with an inner groove (17) for fixing the sealing pressing plate (11).

2. A bicycle middle shaft sealing structure according to claim 1, characterized in that: The inner conical guide groove (61) of the guide dust cover (6) is screwed to the inner wall of one end of the bearing seat (5), and the outer conical dust cover (62) is nested outside the inner conical guide groove (61) to form a double-layer dustproof structure, and the opening direction of the outer conical dust cover (62) is opposite to the travel direction of the bicycle.

3. A bicycle middle shaft sealing structure according to claim 1, characterized in that: The bearing member (7) comprises a bearing body (71), an oil inlet hole (72) and a bearing sealing ring (73), wherein the oil inlet hole (72) is evenly distributed along the annular outer wall of the bearing body (71), and the bearing sealing ring (73) is a double-lip structure and is symmetrically arranged on both sides of the bearing body (71).

4. A bicycle middle shaft sealing structure according to claim 1, characterized in that: The rear sealing ring (8) and the front sealing ring (10) are made of fluororubber, and the cross section of the rear sealing ring (8) is designed in a stepped manner, forming a dynamic sealing compensation mechanism together with the spiral compensation spring (9).

5. The bicycle middle shaft sealing structure according to claim 1, characterized in that: The annular oil channel (14) has a semicircular cross-section, extends circumferentially along the inner wall of the bearing seat (5), and is connected to the oil inlet hole (72) to form a closed-loop lubrication path.

6. A bicycle middle shaft sealing structure according to claim 1, characterized in that: The outer surface of the external positioning ring (15) is provided with anti-slip patterns, and the inner wall thereof is interference-fitted with the bicycle axle frame, thereby ensuring axial positioning stability.

7. The bicycle middle shaft sealing structure according to claim 1, characterized in that: The annular disassembly and assembly openings (16) are evenly spaced along the outer wall of the bearing seat (5), and the depth of each disassembly and assembly opening is 1 / 3 of the wall thickness of the bearing seat (5), so as to facilitate tool insertion and disassembly.

8. The bicycle middle shaft sealing structure according to claim 1, characterized in that: The inner groove (17) is an annular groove, the inner wall of which is provided with a sawtooth-shaped protrusion, which cooperates with the elastic buckle of the sealing pressing plate (11) to achieve bolt-free fixing.

9. The bicycle middle shaft sealing structure according to claim 1, characterized in that: The depth of the inner conical guide groove (61) gradually decreases from the inside to the outside, and the slope of the gradient change of the groove width is positively correlated with the rotation speed of the bicycle center shaft.

10. The bicycle middle shaft sealing structure according to claim 1, characterized in that: The sealing oil plug (12) is made of a silicone material having a thermal expansion coefficient matching that of the bearing seat (5), and an anti-leakage thread is provided on the inner wall of the oil filling port (13).

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