Self-locking structure of worm gear reducer

Abstract

The utility model discloses a kind of self-locking structure of worm gear reducer, including star wheel, drive shaft, power supply mechanism, worm wheel, worm, star wheel is fixedly connected with worm, worm wheel is engaged with worm. Star wheel contains first connecting part, first mounting part, second connecting part, first connecting part is fixedly connected with worm, first mounting part rotatably connected mounting seat, second connecting part outside is provided with a plurality of equidistant connecting blocks along circumference, connecting block is provided with slot hole, and top pin and compression spring are arranged in groove to form self-locking mechanism. Drive shaft includes chassis, pawl and second mounting part, and chassis front end is provided with pawl equidistantly, pawl is inserted between connecting block for driving star wheel rotation, and second mounting part rear end is provided with first connecting hole. Second connecting part is provided with the second connecting hole coaxial with it, two holes and connecting shaft are all hexagonal, and first hole diameter is less than second hole, and the connecting shaft of power supply mechanism is arranged in it to complete transmission.

Description

Technical Field

[0001] This utility model relates to a self-locking structure for a worm gear reducer. Background Technology

[0002] Manual slewing cranes are a type of light lifting equipment widely used in ships, docks, and other similar locations, particularly common on cargo ships in positions such as Suez Canal lighthouse cranes and fuel line cranes. These cranes are typically equipped with a hand-cranked slewing mechanism for manually rotating the boom in the horizontal plane. To ensure the boom remains stably positioned during lifting operations, especially under conditions of ship tilting or wind interference, most existing hand-cranked slewing mechanisms rely on the self-locking performance of a worm gear reducer for braking.

[0003] However, while traditional worm gear structures possess a certain degree of self-locking capability, their transmission efficiency is low when maintaining the self-locking state, typically only around 0.35 to 0.4, resulting in decreased energy utilization. This also necessitates significant manual labor during operation, severely impacting ease of use and efficiency. Furthermore, some manual rotary devices employ ratchet mechanisms for unidirectional braking. While this avoids some issues with reverse rotation and loss of control, manually disengaging the ratchet is required for reverse rotation, causing the device to completely lose its braking function in that state, posing a substantial safety hazard.

[0004] Therefore, there is still an urgent need in the existing technology for a new type of hand-cranked rotary structure that can improve transmission efficiency and achieve bidirectional braking while maintaining a high-efficiency self-locking function, in order to solve the technical problems of traditional structures in terms of efficiency, safety and ease of operation. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a self-locking structure for a worm gear reducer.

[0006] A self-locking structure for a worm gear reducer includes a star wheel, a drive shaft, a power supply mechanism, a worm wheel, and a worm. The star wheel is fixedly connected to the worm, and the worm wheel meshes with the worm. The star wheel includes a first connecting part, a first mounting part, and a second connecting part. The first connecting part is fixedly connected to the worm, the first mounting part is rotatably connected to a mounting base, and the second connecting part is connected to the drive shaft. Multiple connecting blocks are arranged in a circular array along the outer side wall of the second connecting part. Each connecting block is equidistant from the connecting blocks on both sides. A first slot is provided on the end face of both sides of the connecting block. A top pin is movably inserted in the first slot. A second slot is provided on the bottom surface of one side of the top pin. A compression spring is provided between the first slot and the second slot. The two ends of the compression spring abut against the bottom of the first slot and the second slot. In the naturally extended state of the compression spring, the top pin extends out of the first slot. The drive shaft includes a chassis, a pawl, and a second mounting part. The front end face of the chassis is provided with a plurality of pawls arranged equidistantly in a ring along its circumference near the edge. The pawls are inserted between two connecting blocks. The drive shaft is coaxially arranged with the star wheel. The rear end face of the second mounting part is provided with a first connecting hole. The connecting shaft of the power supply mechanism passes through the first connecting hole.

[0007] Furthermore, movable rollers are provided between the pawl and the connecting blocks on both sides.

[0008] Furthermore, the rear end face of the second connecting part is provided with a second connecting hole coaxial with the first connecting hole, and the diameter of the first connecting hole is smaller than the diameter of the second connecting hole.

[0009] Furthermore, the cross-sections of the first connecting hole, the second connecting hole, and the connecting shaft are all hexagonal.

[0010] Furthermore, the outer wall of the first connecting part is provided with a keyway, and the first connecting part passes through the blind hole on the rear end face of the worm. The rotational degree of freedom between the first connecting part and the worm is limited by the flat key, and the axial degree of freedom is provided by the baffle.

[0011] Furthermore, the first mounting part and the second mounting part are rotatably connected in the mounting base via bearings.

[0012] Furthermore, the drive shaft and star wheel restrict axial degrees of freedom by setting baffles at the front and rear.

[0013] A hand-cranked rotary device for a crane using the above-mentioned self-locking structure includes a star wheel, a drive shaft, a drive handle, a slewing bearing, and a worm gear. The star wheel and the worm gear are fixedly connected. The slewing bearing includes an inner ring and an outer ring. The inner ring is fixedly connected to the crane base, and the outer ring is fixedly connected to the crane boom. A gear structure is provided on the outer side of the outer ring, and the gear structure meshes with the helical tooth structure on the surface of the worm gear. The star wheel includes a first connecting part, a first mounting part, and a second connecting part. The first connecting part is fixedly connected to the worm gear, the first mounting part is rotatably connected to the mounting base, and the second connecting part is connected to the drive shaft. The outer wall of the second connecting part is arranged with multiple connecting blocks in a circumferential array. Each connecting block is equidistant from the connecting blocks on both sides. The end faces of both sides of the connecting block are provided with a first slot. A top pin is movably inserted in the first slot. A second slot is provided on the bottom surface of one side of the top pin. A compression spring is provided between the first slot and the second slot. The two ends of the compression spring abut against the bottom of the first slot and the second slot. In the naturally extended state of the compression spring, the top pin extends out of the first slot. The drive shaft includes a chassis, a pawl, and a second mounting part. The front end face of the chassis is provided with a plurality of pawls arranged equidistantly in a ring along its circumference near the edge. The pawls are inserted between two connecting blocks. The drive shaft is coaxially arranged with the star wheel. The rear end face of the second mounting part is provided with a first connecting hole. The drive handle includes a rod, with a handle and a connecting shaft at each end, and the connecting shaft passes through the first connecting hole.

[0014] Furthermore, movable rollers are provided between the pawl and the connecting blocks on both sides.

[0015] Furthermore, the rear end face of the second connecting part is provided with a second connecting hole coaxial with the first connecting hole. The diameter of the first connecting hole is smaller than the diameter of the second connecting hole. The cross-sections of the first connecting hole, the second connecting hole, and the connecting shaft are all hexagonal.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following advantages: First, this structure replaces the traditional worm gear one-way self-locking method with a mechanical top pin and compression spring self-locking mechanism, which not only achieves a two-way self-locking function, but also greatly improves the transmission efficiency, reaching more than 0.85, which is far better than the efficiency level of only 0.35 to 0.4 of the traditional structure. This effectively reduces the burden of manual operation and improves the overall performance of the machine.

[0017] Secondly, the "unlock-transmission" separate structure design between the drive shaft and the star wheel allows the pawl to only perform the unlocking function, while the torque is entirely transmitted by the star wheel. This avoids the occurrence of jamming in the initial stage of operation, ensures the smoothness and efficiency of manual drive, and improves the structural reliability and ease of operation of the system.

[0018] Furthermore, the hexagonal connecting holes and shaft design ensure a more stable and reliable power transmission, preventing slippage. The stepped coaxial holes further enhance connection precision, guaranteeing overall structural stability and ease of assembly. Simultaneously, the rollers effectively reduce friction between structural components, extending the device's service life and improving maintenance intervals.

[0019] In addition, the entire self-locking mechanism is easy to install and has a compact structure. Through bearing support and baffle limiting design, it ensures the axial and radial stability of each component during operation, making it particularly suitable for use in lifting machinery and equipment with limited space and high reliability requirements.

[0020] In summary, this invention not only improves the efficiency and stability of the rotary transmission system, but also significantly enhances self-locking safety and ease of operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the self-locking structure of a worm gear reducer; Figure 2 yes Figure 1 A schematic diagram of the AA direction; Figure 3 This is a schematic diagram of the star wheel; Figure 4 This is a partial sectional view of the star wheel; Figure 5 This is a schematic diagram of the drive shaft; Figure 6 This is a schematic diagram of the assembly of a slewing bearing and a crane; Figure 7 This is a schematic diagram of the drive handle. In the diagram, 1. Slewing bearing, 2. Inner ring, 3. Outer ring, 4. Worm gear, 5. Mounting base, 6. Star wheel, 7. Drive shaft, 8. Drive handle, 9. Roller, 10. Pad, 11. First connecting part, 12. First mounting part, 13. Second connecting part, 14. Chassis, 15. Second mounting part, 16. Pad, 17. Crane base, 18. Crane boom, 19. Rod, 20. Connecting shaft, 21. Handle, 22. Connecting block, 23. Spring, 24. Top pin, 25. Roller. Detailed Implementation

[0022] To enhance understanding of this utility model, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. These embodiments are only used to explain the present utility model and do not constitute a limitation on the scope of protection of the present utility model. Example

[0023] A self-locking structure for a worm gear reducer includes a star wheel 6, a drive shaft 7, a power supply mechanism, a worm wheel, and a worm 4. The star wheel 6 is fixedly connected to the worm 4, and the worm wheel meshes with the worm 4. The star wheel 6 includes a first connecting part 11, a first mounting part 12, and a second connecting part 13. The first connecting part 11 has a keyway on its outer side and is fixedly connected to the worm 4 by inserting a flat key into a blind hole at the rear end, with axial displacement restricted by a baffle. The first mounting part 12 is mounted in a mounting base 5 by bearings for rotatable connection. The second connecting part 13 is connected to the drive shaft 7, and its rear end face has a second connecting hole coaxial with the first connecting hole of the drive shaft 7. Both connecting holes have hexagonal cross-sections, with the diameter of the first hole being smaller than that of the second hole, for insertion into a connecting shaft 20.

[0024] The second connecting part 13 has multiple equidistantly distributed connecting blocks 22 on its outer side along the circumference. Each connecting block 22 has a first slot on both sides, and a top pin 24 is movably inserted into the slot. The bottom of the top pin 24 has a second slot, and a compression spring is provided between the two slots. The two ends of the compression spring abut against the bottom of the slot. In its naturally extended state, the top pin 24 extends out of the connecting block 22 to achieve self-locking and limiting. The drive shaft 7 includes a chassis 14, a pawl 10, and a second mounting part 15. The front periphery of the chassis 14 has multiple pawls 10, which are embedded between adjacent connecting blocks 22 for unlocking.

[0025] Drive shaft 7 rotates pawl 10 via manual or other power input. First, pawl 10 pushes roller 9 between connecting blocks 22 to press top pin 24, compressing the compression spring to unlock. Then, drive shaft 7 engages with the hexagonal hole of the second connecting part 13 of star wheel 6 through hexagonal connecting shaft 20, transmitting torque and driving worm 4 to rotate, thus enabling power output from the worm wheel. When star wheel 6 stops rotating, the compression spring causes top pin 24 to spring back into connecting block 22, achieving automatic mechanical locking and preventing worm 4 from reversing.

[0026] In one possible implementation, a movable roller 9 is provided between the pawl 10 and the connecting blocks 22 on both sides.

[0027] The roller 9 is installed between the pawl 10 and the connecting block 22. During the rotation and pushing of the pawl 10, the roller 9 rolls and pushes the top pin 24 to complete the unlocking, effectively reducing frictional resistance and ensuring smooth operation.

[0028] In one possible implementation, the outer wall of the first connecting part 11 is provided with a keyway, and the first connecting part 11 passes through the blind hole on the rear end face of the worm 4. The rotational degree of freedom is limited by the flat key, and the axial degree of freedom is limited by the baffle.

[0029] The torque transmission between the star wheel 6 and the worm gear 4 is achieved through a keyway, while a baffle is used to prevent the star wheel 6 from slipping axially, ensuring its positional stability during transmission.

[0030] In one possible implementation, the first mounting part 12 and the second mounting part 15 are rotatably connected in the mounting base 5 via bearings.

[0031] The bearing support ensures that the star wheel 6 and drive shaft 7 maintain a low-friction, high-precision motion state during rotation, which helps to improve the overall operating efficiency and service life of the machine.

[0032] In one possible implementation, the drive shaft 7 and the star wheel 6 restrict axial degrees of freedom by setting baffles at the front and rear.

[0033] By setting baffles in front of and behind the drive shaft 7 and star wheel 6, their range of movement in the axial direction is limited, ensuring that they remain axially stable under stress and preventing dislocation or structural loosening.

[0034] It should be noted that the toroidal worm 4 of the slewing bearing is made of 42CrMo material and undergoes nitriding treatment to improve the hardness of the worm 4. The end of the worm 4 has a flat keyway and a shaft hole.

[0035] To improve transmission efficiency, the lead angle of the worm 4 of the slewing bearing 17 when meshing with the outer ring 3 of the slewing bearing 1 is generally between 20° and 28°, which can make the transmission efficiency of the slewing bearing reach more than 0.85; while for slewing bearings with self-locking performance, the lead angle of the worm 4 when meshing with the outer ring 3 of the bearing is generally ≤5°.

[0036] During operation, the contact angle between the star wheel 6, roller 9, and the inner wall of the mounting base 5 should generally be between 5.71° and 6.84° to ensure the passive braking performance of the hand-cranked rotary device.

[0037] Star wheel 6 and mounting base 5 should generally be hardened, and roller 9 should be carburized to ensure the braking strength of the hand-cranked rotary device.

[0038] Each connecting block 22 of the star is equidistant from the connecting blocks 22 on both sides to ensure bidirectional braking of the manual rotation device.

[0039] The mounting base 5, star wheel 6, and drive shaft 7 are generally lubricated with low-viscosity gear oil instead of grease to ensure the braking performance of the hand-cranked rotary device. Example

[0040] A hand-cranked slewing device for a crane with a self-locking structure, as described in Application Embodiment 1, includes a star wheel 6, a drive shaft 7, a drive handle 8, a slewing bearing 1, and a worm gear 4. The star wheel 6 and the worm gear 4 are fixedly connected. The slewing bearing 1 includes an inner ring 2 and an outer ring 3. The inner ring 2 is fixedly connected to the crane base 17, and the outer ring 3 is connected to the boom. A gear structure is provided on the outer side of the outer ring 3 and meshes with the helical gear structure of the worm gear 4. The star wheel 6 consists of a first connecting part 11, a first mounting part 12, and a second connecting part 13, with the same structure as described above. The drive shaft 7 includes a chassis 14, a pawl 10, and a second mounting part 15, with the same structure as described above. The drive handle 8 has a rod part 19, with handles 21 and a connecting shaft 20 at both ends. The connecting shaft 20 passes through the first and second connecting holes of the star wheel 6, forming a power input path.

[0041] The operator drives the drive shaft 7 to rotate via the drive handle 8. The pawl 10 first unlocks the top pin 24, and then engages with the star wheel 6 through the connecting shaft 20 to form a power transmission path, so that the star wheel 6 drives the worm gear 4, and then the worm gear 4 engages with the outer ring 3 gear of the slewing bearing 1 to complete the slewing control of the crane boom 18. After the rocking stops, the top pin 24 automatically resets and inserts into the connecting block 22 under the action of the compression spring, realizing bidirectional mechanical self-locking.

[0042] In one possible implementation, a movable roller 9 is provided between the pawl 10 and the connecting blocks 22 on both sides.

[0043] The pawl 10 pushes the roller 9 to roll, causing the top pin 24 to press in and complete the unlocking action, forming a complete closed loop of unlocking-driving-self-locking, ensuring smooth and reliable hand-cranking operation.

[0044] Working principle: In this device, the input end of the drive shaft 7 is provided with an internal hexagonal hole, the diameter of which is designed to be slightly smaller than the corresponding internal hexagonal hole diameter of the star wheel 6 by 0.3-0.5mm, forming a "gap-type coaxial insertion structure". When the operator rotates the drive shaft 7 by hand crank, due to the fit gap between the drive shaft 7 and the star wheel 6, the drive shaft 7 will not immediately drive the star wheel 6 to rotate during the initial rotation. Instead, its pawl 10 first acts on the roller 9 between the connecting blocks 22, causing it to press against the top pin 24, thereby compressing the compression spring and completing the mechanical unlocking process of the star wheel 6.

[0045] During this process, the pawl 10 is only responsible for the unlocking action and does not bear the transmission load, thus avoiding the jamming problem between the drive shaft 7 and the star wheel 6. As the unlocking is completed, when the hand crank continues to apply force, the hexagonal hole of the drive shaft 7 and the hexagonal hole of the star wheel 6 gradually mesh and engage, thus truly beginning to transmit torque. The star wheel 6 then drives the worm gear 4, completing the rotation of the entire machine.

[0046] This design effectively separates the unlocking and transmission mechanisms. The pawl 10 of the drive shaft 7 is dedicated to "unlocking," while the star wheel 6 acts as the "main force transmission component" to complete torque transmission. This structural arrangement improves the smoothness of the overall transmission, avoids structural jamming in the initial stage of rotation, and ensures smooth operation during bidirectional rotation, thus enhancing the practicality and operability of the entire hand-cranked rotary mechanism.

[0047] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A self-locking structure for a worm gear reducer, characterized in that, The system includes a star wheel, a drive shaft, a power supply mechanism, a worm gear, and a worm. The star wheel and the worm are fixedly connected, and the worm gear meshes with the worm. The star wheel includes a first connecting part, a first mounting part, and a second connecting part. The first connecting part is fixedly connected to the worm. The first mounting part is rotatably connected to a mounting base. The second connecting part is connected to the drive shaft. Multiple connecting blocks are arranged in a circular array along the outer side wall of the second connecting part. Each connecting block is equidistant from the connecting blocks on both sides. The end faces of both sides of the connecting block are provided with a first slot. A top pin is movably inserted into the first slot. A second slot is provided on one side of the bottom surface of the top pin. A compression spring is provided between the first slot and the second slot. The two ends of the compression spring abut against the bottom of the first slot and the second slot. In the naturally extended state of the compression spring, the top pin extends out of the first slot. The drive shaft includes a chassis, a pawl, and a second mounting part. The front end face of the chassis is provided with a plurality of pawls arranged equidistantly in a ring along its circumference near the edge. The pawls are inserted between two connecting blocks. The drive shaft is coaxially arranged with the star wheel. The rear end face of the second mounting part is provided with a first connecting hole. The rear end face of the second connecting part is provided with a second connecting hole coaxial with the first connecting hole. The diameter of the first connecting hole is smaller than the diameter of the second connecting hole. The cross-sections of the first connecting hole, the second connecting hole, and the connecting shaft are all hexagonal. The connecting shaft of the power supply mechanism passes through the first connecting hole and the second connecting hole.

2. The self-locking structure according to claim 1, characterized in that, Movable rollers are provided between the claw and the connecting blocks on both sides.

3. The self-locking structure according to claim 1, characterized in that, The outer wall of the first connecting part is provided with a keyway. The first connecting part passes through the blind hole on the rear end face of the worm. The rotational degree of freedom between the first connecting part and the worm is limited by a flat key, and the axial degree of freedom is provided by a baffle.

4. The self-locking structure according to claim 1, characterized in that, The first mounting part and the second mounting part are rotatably connected in the mounting base by bearings.

5. The self-locking structure according to claim 1, characterized in that, The drive shaft and star wheel restrict axial freedom by setting baffles at the front and rear.

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