CN214524385U

CN214524385U - Gear reduction box for unmanned helicopter

Info

Publication number: CN214524385U
Application number: CN202120841091.7U
Authority: CN
Inventors: 郑锋
Original assignee: Military Research Technology And Industry Intelligent Technology Development Tianjin Co ltd
Current assignee: Military Research Technology And Industry Intelligent Technology Development Tianjin Co ltd
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2021-10-29
Anticipated expiration: 2031-04-22

Abstract

The utility model discloses a gear reduction box for unmanned helicopter relates to unmanned helicopter technical field, including the reduction box main part and rotate the gear shaft that sets up in reduction box main part one side, it is provided with hollow main shaft to rotate in the reduction box main part, and hollow main shaft exposes the part and is provided with oar hub central component, is provided with the hollow interior axle that passes from hollow main shaft in the reduction box main part, and hollow interior axle upper portion stretches out hollow main shaft and is provided with the installation component, is provided with equipment storehouse on the installation component, and the inside overhead of hollow main shaft is provided with the cable of being connected with overhead equipment storehouse. The utility model provides a use convenient reliable, and accommodation is wide, can avoid the rotor to shelter from a gear reduction box for unmanned helicopter of communication signal through the form in hollow main shaft upper portion overhead equipment storehouse.

Description

Gear reduction box for unmanned helicopter

Technical Field

The utility model relates to an unmanned helicopter technical field especially relates to a gear reduction box for unmanned helicopter.

Background

The pilotless airplane is an unmanned helicopter controlled by radio remote controller and program controller. The machine has no cockpit, but is provided with an automatic pilot, a program control device, a signal acquisition device and other equipment. The personnel on the ground, the naval vessel or the mother aircraft remote control station can track, position, remotely control, telemeter and digitally transmit the personnel through equipment such as a radar.

The current chinese utility model patent that the publication number of granting is CN205707383U discloses an unmanned helicopter, including fuselage, main rotor, tail rotor, steering wheel, engine and reducing gear box, the reducing gear box is connected with the engine, and unmanned helicopter still includes: the supporting component is arranged in the machine body; the landing gear is fixed at the bottom of the machine body; the thrust amplification mechanism is connected with the steering engine; the cooling device is connected with the reduction gearbox; and the fixing device is sleeved on the tail transmission shaft and is fixedly connected with the machine body.

Adopt above-mentioned technical scheme, make unmanned helicopter can the steady operation through installation fixing device on the tail transmission shaft, but because its communication equipment etc. all set up inside the fuselage to lead to the staff when tracking the location through the satellite, unmanned helicopter inside communication equipment can receive the rotor with satellite communication signal and shelter from, lead to the unstability of communication.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a gear reduction box for unmanned helicopter adopts the mode of wearing to establish the hollow interior axle support that links firmly with the gear reduction box main part in the hollow main shaft, sets up the rotor top with overhead equipment storehouse to can effectively avoid the rotor to shelter from the problem of communications facilities and satellite communication signal, improve the stability of communication.

The above technical purpose of the present invention can be achieved by the following technical solutions:

the gear reduction box comprises a reduction box main body and a gear shaft rotatably arranged on one side of the reduction box main body, wherein a hollow main shaft is rotatably arranged on the reduction box main body, a hub central component is arranged on the exposed part of the hollow main shaft, a hollow inner shaft penetrating through the hollow main shaft is arranged on the reduction box main body, the upper part of the hollow inner shaft extends out of the hollow main shaft and is provided with an installation component, an overhead equipment bin is arranged on the installation component, and a cable connected with the overhead equipment bin is arranged inside the hollow main shaft.

Through adopting above-mentioned technical scheme, support propeller hub central component through hollow main shaft, support the installation component with the fixed hollow interior axle that passes from hollow main shaft in reducing gear box main part lower part, install overhead equipment storehouse on the installation component, utilize the cable to carry out power supply and communication to overhead equipment storehouse inside, thereby make the rotor when rotatory, overhead equipment storehouse is located the rotor top, and relatively fixed with reducing gear box main part position, through this kind of mode, can effectively avoid the rotor to shelter from the problem of communication equipment and satellite communication signal when moving, improve the stability of communication.

The utility model discloses further set up to: the mounting assembly comprises a mounting seat in threaded connection with the upper end of the hollow inner shaft, and the overhead equipment bin is fixedly arranged on the mounting seat.

Through adopting above-mentioned technical scheme, utilize threaded connection's mount pad and hollow interior epaxial end to be connected to make things convenient for the staff to carry out the dismantlement of hollow interior axle, improve the convenience that the device used.

The utility model discloses further set up to: the hollow inner shaft is provided with a clamping table in the upper end, the clamping table is clamped with an orientation seat, and a locking piece is fixedly connected between the orientation seat and the mounting seat.

By adopting the technical scheme, the clamping table is utilized to limit the orientation seat, and the mounting seat and the orientation seat are locked by the locking piece, so that the relative rotation between the mounting seat and the hollow inner shaft can be prevented, and the use reliability of the device is further improved.

The utility model discloses further set up to: the lower end of the hollow inner shaft extends out of the hollow main shaft and is fixedly connected with a fixing seat, the fixing seat is fixedly arranged on the bottom surface of the speed reducer main body, and an opening communicated with the inside of the hollow inner shaft is formed in the fixing seat.

By adopting the technical scheme, the hollow inner shaft is fixed by the fixing seat fixedly arranged on the reduction gearbox main body, so that the hollow inner shaft can not rotate along with the hollow main shaft to ensure the stability of the overhead equipment bin; on the other hand, make things convenient for the cable to penetrate inside the hollow main shaft from the reducing gear box main part outside, through this kind of mode, improve the convenience that the device used.

The utility model discloses further set up to: the upper portion of the hollow main shaft is formed with a first key groove, a spline which is in plug-in fit with the first key groove is fixed inside the hub central component, and a locking mechanism used for locking the hub central component is arranged on the hollow main shaft.

Through adopting above-mentioned technical scheme, utilize on the hollow main shaft first keyway and spline fit to carry on spacingly to propeller hub central member, utilize locking mechanism to lock propeller hub central member, through this kind of mode, make things convenient for the staff to carry out the dismantlement and the change of different grade type propeller hub central member, improve the suitability that the device used.

The utility model discloses further set up to: the locking mechanism comprises a tensioning sleeve which is sleeved on the upper portion of the hollow main shaft, a first inclined surface is formed on the upper portion of the hollow main shaft, a second inclined surface which is in butt fit with the first inclined surface is formed on the inner side of the tensioning sleeve, a butting platform which is in butt fit with the tensioning sleeve is formed inside the hub central component, and a main shaft nut which is in butt fit with the hub central component is in threaded connection with the upper end of the hollow main shaft.

Through adopting above-mentioned technical scheme, when carrying out the locking of propeller hub central component, only need to establish on the hollow main shaft with the tight cover that rises earlier until first inclined plane and second inclined plane butt cooperation, first keyway department is received with propeller hub central component cover again, until support tight platform and tight cover butt that rises, screw spindle nut from hollow main shaft upper end at last, thereby make spindle nut and the tight common cooperation of the cover that rises with propeller hub central component locking, through this kind of mode, when locking propeller hub central component, can prevent effectively that spindle nut from taking off, thereby improve the reliability that the device used.

The utility model discloses further set up to: the upper part of the spindle nut extends out of the hollow spindle and is fixedly provided with a bearing which is in running fit with the hollow inner shaft.

By adopting the technical scheme, the bearing fixedly arranged on the spindle nut is matched with the hollow inner shaft, so that the running stability of the hollow spindle can be improved, and meanwhile, the friction force between the hollow spindle and the hollow inner shaft can be effectively reduced, thereby preventing the hollow inner shaft and the hollow spindle from being abraded, and improving the use reliability of the device.

The utility model discloses further set up to: the gear shaft stretches out the partial shaping of gear box main part has the ladder platform, ladder platform department is fixed to be provided with the parallel key, the grafting is provided with the driving medium on the gear shaft, the shaping has the second keyway with the parallel key grafting complex on the driving medium, threaded connection has the stop nut with driving medium butt complex on the gear shaft. .

Through adopting above-mentioned technical scheme, utilize and cup joint second keyway and flat key and carry on spacingly to the driving medium, utilize limit nut to lock the driving medium to make the power input of device different, carry out the change of different grade type driving mediums, through this kind of mode, improve the suitability that the device used.

The utility model discloses further set up to: the cable fixing device is characterized in that limiting tables are formed at two ends of the inner hollow shaft, L-shaped guide grooves are formed at two ends of the inner hollow shaft, two lantern rings are sleeved on a cable, guide pillars matched with the L-shaped guide grooves in a sliding mode are formed on the lantern rings, elastic pieces matched with the limiting tables in an abutting mode are arranged in the lantern rings, and a cable fastening mechanism is arranged inside the lantern rings.

Through adopting above-mentioned technical scheme, utilize guide pillar and L type guide slot to carry on spacingly to the lantern ring, utilize elastic component and spacing platform to apply the pretightning force and lock the lantern ring to the lantern ring, utilize cable fastening device to carry out the fixed of cable to effective prevention device is in the motion process hollow interior axle both ends cause wearing and tearing to the cable, thereby leads to the cable to become invalid, through this kind of mode, improves the reliability that the device used.

The utility model discloses further set up to: the cable fastening mechanism comprises a flexible holding ring fixedly arranged in a lantern ring, a first guide surface is formed on the flexible holding ring, a sliding ring is arranged in the lantern ring in a sliding mode, the elastic piece is fixedly arranged on the sliding ring, and a second guide surface in butt fit with the first guide surface is formed on the sliding ring.

By adopting the technical scheme, when the cable clamping device works, only the sleeve ring needs to be inserted into a cable and inserted into the hollow inner shaft, at the moment, the guide pillar slides along the L-shaped guide groove, when the elastic piece is abutted and matched with the limiting table, the elastic piece contracts and pushes the sliding ring to move towards the flexible clamping ring, and the flexible clamping ring is driven to clamp the cable under the action of the first guide surface and the second guide surface; at the moment, the guide post rotates along the L-shaped guide groove, so that the locking of the lantern ring is completed under the cooperation of the elastic pieces.

To sum up, the utility model discloses a beneficial technological effect does:

(1) the overhead equipment bin is arranged above the rotor wing by adopting a mode that a hollow inner shaft support fixedly connected with the main body of the reduction gearbox is penetrated in the hollow main shaft, so that the problem that the communication equipment and satellite communication signals are blocked by the rotor wing can be effectively avoided, and the communication stability is improved;

(2) the detachable mounting seat, the detachable hub central component and the transmission part are utilized, so that workers can conveniently replace the hub central components and the transmission parts of different types, the device can adapt to the hub central components of different power inputs and different blade quantities, and the use applicability of the device is improved;

(3) the bearing fixed on the spindle nut is used for improving the running stability of the hollow spindle and the abrasion between the hollow spindle and the hollow inner shaft, and the lantern ring and the cable fastening mechanism are used for fixing the cable, so that the abrasion of two ends of the hollow inner shaft to the cable is effectively prevented, and the use reliability of the device is improved in the mode.

Drawings

Fig. 1 is a schematic cross-sectional view of the overall structure of an embodiment of the present invention;

fig. 2 is a partially enlarged schematic view of a portion a of fig. 1, showing the structure of the mounting assembly and the cable fastening mechanism.

Reference numerals: 1. a main body of the reduction box; 2. a hollow main shaft; 3. a fixed seat; 4. a hollow inner shaft; 5. opening a hole; 6. a mounting seat; 7. clamping a platform; 8. an orientation base; 9. a locking member; 10. an overhead equipment bin; 11. a limiting table; 12. an L-shaped guide groove; 13. a cable; 14. a collar; 15. a guide post; 16. an elastic member; 17. a flexible clasping ring; 18. a first guide surface; 19. a slip ring; 20. a second guide surface; 21. a hub central member; 22. a first keyway; 23. a spline; 24. a tensioning sleeve; 25. a first inclined plane; 26. a second inclined plane; 27. a propping platform; 28. a spindle nut; 29. a bearing; 30. a gear shaft; 31. a bevel gear; 32. a stair step; 33. a flat bond; 34. a transmission member; 35. a second keyway; 36. and a limiting nut.

Detailed Description

The present invention will now be described more fully hereinafter with reference to the accompanying examples.

Referring to the attached figure 1, the gear reduction box for the unmanned helicopter comprises a reduction box main body 1, a hollow main shaft 2 is rotatably arranged inside the reduction box main body 1, a fixed seat 3 is fixed on the bottom surface of the outside of the reduction box main body 1, a hollow inner shaft 4 penetrating through the inside of the hollow main shaft 2 is fixed on the fixed seat 3, an opening 5 communicated with the inside of the hollow inner shaft 4 is formed in the fixed seat 3, and the upper portion of the hollow inner shaft 4 extends out of the hollow main shaft 2 and is provided with a mounting assembly.

Referring to the attached drawing 2, the mounting assembly comprises a mounting seat 6 in threaded connection with the upper end of a hollow inner shaft 4, the mounting seat 6 is of a disc-shaped structure, a clamping table 7 is formed at the upper end of the hollow inner shaft 4, a positioning seat 8 is arranged at the clamping position of the clamping table 7 in a clamped mode, the positioning seat 8 is of a disc-shaped structure, a locking piece 9 is fixedly connected between the positioning seat 8 and the mounting seat 6, the locking piece 9 is a bolt, an overhead equipment bin 10 is arranged on the positioning seat 8, and the overhead equipment bin 10 is clamped and arranged between the positioning seat 8 and the mounting seat 6 and is locked and fixed on the mounting seat 6 through the locking piece 9.

The overhead equipment bin 10 is fixed by the mounting seat 6 which is in threaded connection with the hollow inner shaft 4, so that the overhead equipment bin 10 can be conveniently detached by a worker, and meanwhile, the mounting seat 6 which is detachably arranged also facilitates the mounting and the detachment of the hollow inner shaft 4; carry on spacingly to directional seat 8 through ka tai 7, further lock directional seat 8 and mount pad 6 through closure 9, can effectively prevent that mount pad 6 and hollow interior axle 4 from taking place relative rotation in the use, improve the stability of overhead equipment storehouse 10 installation, through this kind of mode, can effectively improve the convenience and the reliability that the device used.

4 inner wall both ends in the hollow are all moulded and are had spacing platform 11, 4 inner wall both ends in the hollow all moulded and have L type guide slot 12, the cable 13 with the inside intercommunication in overhead equipment storehouse 10 is worn to be equipped with in the hollow 4 inner wall, cable 13 cup joints and is provided with two lantern rings 14, two lantern rings 14 correspond respectively and set up in the hollow 4 both ends in, the shaping has the guide pillar 15 that slides the complex with L type guide slot 12 on the lantern ring 14 outer wall, be provided with in the lantern ring 14 with spacing 11 butt complex elastic component 16, elastic component 16 is made for the spring, the inside cable fastening device that is provided with of lantern ring 14.

The cable fastening device is including fixed flexible enclasping ring 17 that sets up in lantern ring 14 inside, flexible enclasping ring 17 is made for rubber materials, the shaping of flexible enclasping ring 17 outer wall downside has first spigot surface 18, the inside below of lantern ring 14 slides along its axis direction and is provided with sliding ring 19, sliding ring 19 is the echelonment structure, elastic component 16 is fixed to be set up on sliding ring 19 stretches out the terminal surface of lantern ring 14, the shaping of sliding ring 19 inner wall upper portion has with second spigot surface 20 butt complex second spigot surface 20.

When the cable clamp works, only the lantern ring 14 needs to penetrate into the cable 13, the lantern ring 14 is inserted into the hollow inner shaft 4, at the moment, the guide post 15 slides along the L-shaped guide groove 12, when the elastic piece 16 is abutted and matched with the limiting table 11, the elastic piece 16 contracts and pushes the sliding ring 19 to move towards the flexible enclasping ring 17, and under the action of the first guide surface 18 and the second guide surface 20, the inner wall of the flexible enclasping ring 17 enclaves the cable 13; at the moment, the guide post 15 rotates along the L-shaped guide groove 12, so that the locking of the lantern ring 14 is completed under the cooperation of the elastic piece 16, and by means of the mode, the cable 13 is effectively prevented from being worn by two ends of the hollow inner shaft 4 in the movement process of the device, the failure of the cable 13 is caused, and the use reliability of the device is improved.

Referring to the attached drawing 1, the exposed part of the upper end of the hollow main shaft 2 extending out of the reduction gearbox body 1 is provided with a hub central member 21 in an inserted manner, the upper part of the hollow main shaft 2 is formed with a first key groove 22, a spline 23 in inserted and matched with the first key groove 22 is fixed inside the hub central member 21, and the hollow main shaft 2 is provided with a locking mechanism for locking the hub central member 21.

Utilize spline 23 and first keyway 22 to carry on spacingly to propeller hub central member 21 to with the cooperation of locking mechanism realize the dismantlement setting of propeller hub central member 21, thereby can ensure under the state that the main shaft is not changed, change many blades rotor systems such as 2 paddles, 3 paddles, 4 paddles of different specifications, improve the suitability that the device used.

The locking mechanism comprises a tensioning sleeve 24 which is sleeved on the upper portion of the hollow main shaft 2, the tensioning sleeve 24 is of a circular ring structure, a first inclined surface 25 is formed on the upper portion of the hollow main shaft 2, a second inclined surface 26 which is in butt joint with the first inclined surface 25 and is matched with the first inclined surface 25 in a butt joint mode is formed on the inner side of the tensioning sleeve 24, a butt joint platform 27 which is in butt joint with the tensioning sleeve 24 is formed inside the hub central member 21, a main shaft nut 28 which is in butt joint with the hub central member 21 is in threaded connection with the upper end of the hollow main shaft 2, and a bearing 29 (marked in figure 2) which is in running fit with the hollow inner shaft 4 is fixedly arranged on the upper portion of the main shaft nut 28 and extends out of the hollow main shaft 2.

When the hub central member 21 is locked, the tensioning sleeve 24 is sleeved on the hollow main shaft 2 until the first inclined surface 25 is abutted against and matched with the second inclined surface 26, the hub central member 21 is sleeved on the first key groove 22 until the abutting table 27 is abutted against the tensioning sleeve 24, and finally the main shaft nut 28 is screwed from the upper end of the hollow main shaft 2, so that the main shaft nut 28 and the tensioning sleeve 24 are matched together to lock the hub central member 21, and by the mode, the main shaft nut 28 can be effectively prevented from loosening while the hub central member 21 is locked; on the other hand, the hollow spindle 2 is supported by the bearing 29 matched with the hollow inner shaft 4 to improve the operation stability, and meanwhile, the abrasion of the hollow inner shaft 4 and the hollow spindle 2 is effectively reduced, so that the use reliability of the device is improved.

The gear shaft 30 extending into the interior of the reduction gearbox body 1 is rotatably arranged on one side of the reduction gearbox body 1, the bevel gear 31 meshed with the gear shaft 30 is fixedly arranged on the part, extending into the reduction gearbox body 1, of the hollow spindle 2, the step table 32 is formed on the part, extending out of the reduction gearbox body 1, of the gear shaft 30, the flat key 33 is fixedly arranged at the position of the step table 32, a transmission piece 34 is arranged on the gear shaft 30 in an inserted mode, the transmission piece 34 can be a gear or a belt wheel, a second key groove 35 in inserted mode with the flat key 33 is formed in the transmission piece 34, and the gear shaft 30 is in threaded connection with a limit nut 36 in abutted fit with the transmission piece 34.

The transmission piece 34 is limited by the sleeving second key groove 35 and the flat key 33, and the transmission piece 34 is locked by the limiting nut 36, so that the transmission piece 34 can be quickly detached and replaced according to an external power source, for example, when the power input source is a motor, a gear can be used as the transmission piece 34; when the power input source is a belt reduction box type, a belt wheel can be adopted as the transmission part 34, and the applicability of the gear reduction box can be further improved by the mode.

The working principle of the embodiment is as follows: supporting a hub central component 21 and a rotor wing system through a hollow main shaft 2, supporting a mounting assembly through a hollow inner shaft 4 which is fixed with the lower part of a speed reducer main body 1 and penetrates through the hollow main shaft 2, fixing an overhead equipment bin 10 on the mounting assembly, and supplying power and communicating with the inside of the overhead equipment bin 10 through a cable 13 which penetrates through the hollow inner shaft 4, so that when the rotor wing rotates, the overhead equipment bin 10 is positioned above the rotor wing and is fixed relative to the position of the speed reducer main body 1; meanwhile, the detachable hub central member 21 enables the device to adapt to rotor systems with different specifications, and the detachable transmission piece 34 enables the device to adapt to power sources with different specifications; through this kind of mode, can effectively avoid rotor to shelter from the problem of communications facilities and satellite communication signal when operation, improve the stability of communication.

The above, only do the preferred embodiment of the present invention, not limit the protection scope of the present invention according to this, so: all equivalent changes made according to the structure, shape and principle of the utility model are covered within the protection scope of the utility model.

Claims

1. The utility model provides a gear reduction box for unmanned helicopter, includes reduction box main part (1) and rotates gear shaft (30) that set up in reduction box main part (1) one side, its characterized in that: the reduction gearbox is characterized in that a hollow main shaft (2) is rotatably arranged on the reduction gearbox main body (1), a hub central component (21) is arranged at the exposed part of the hollow main shaft (2), a hollow inner shaft (4) penetrating through the hollow main shaft (2) is arranged on the reduction gearbox main body (1), the upper part of the hollow inner shaft (4) extends out of the hollow main shaft (2) and is provided with an installation component, an overhead equipment bin (10) is arranged on the installation component, and a cable (13) connected with the overhead equipment bin (10) is arranged inside the hollow main shaft (2).

2. The gear reducer for the unmanned helicopter of claim 1, wherein: the mounting assembly comprises a mounting seat (6) in threaded connection with the upper end of the hollow inner shaft (4), and the overhead equipment bin (10) is fixedly arranged on the mounting seat (6).

3. The gear reducer for the unmanned helicopter of claim 2, wherein: the hollow inner shaft (4) is provided with a clamping table (7) at the upper end, the clamping table (7) is provided with an orientation seat (8) in a clamping manner, and a locking piece (9) is fixedly connected between the orientation seat (8) and the mounting seat (6).

4. The gear reducer for the unmanned helicopter of claim 1, wherein: the lower end of the hollow inner shaft (4) extends out of the hollow main shaft (2) and is fixedly connected with a fixing seat (3), the fixing seat (3) is fixedly arranged on the bottom surface of the speed reducer main body (1), and a hole (5) communicated with the inside of the hollow inner shaft (4) is formed in the fixing seat (3).

5. The gear reducer for the unmanned helicopter of claim 1, wherein: a first key groove (22) is formed in the upper portion of the hollow main shaft (2), a spline (23) which is in plug-in fit with the first key groove (22) is fixed inside the hub central component (21), and a locking mechanism used for locking the hub central component (21) is arranged on the hollow main shaft (2).

6. The gear reducer for the unmanned helicopter of claim 5, wherein: locking mechanism is including cup jointing setting at hollow main shaft (2) upper portion tight cover (24) that rises, hollow main shaft (2) upper portion shaping has first inclined plane (25), tight cover (24) inboard shaping has with first inclined plane (25) butt cooperation side second inclined plane (26) rises, hub central member (21) inside shaping has with rise tight cover (24) butt complex to tight platform (27), hollow main shaft (2) upper end threaded connection has with hub central member (21) butt complex spindle nut (28).

7. The gear reducer for the unmanned helicopter of claim 6, wherein: the upper part of the spindle nut (28) extends out of the hollow spindle (2) and is fixedly provided with a bearing (29) which is rotationally matched with the hollow inner shaft (4).

8. The gear reducer for the unmanned helicopter of claim 1, wherein: the gear shaft (30) stretch out the part shaping of gear box main part (1) and have step platform (32), step platform (32) department is fixed to be provided with parallel key (33), it is provided with driving medium (34) to peg graft on gear shaft (30), the shaping has second keyway (35) with parallel key (33) grafting complex on driving medium (34), threaded connection has and driving medium (34) butt complex stop nut (36) on gear shaft (30).

9. The gear reducer for the unmanned helicopter of claim 1, wherein: limiting tables (11) are formed at two ends of the inner portion of the hollow inner shaft (4), L-shaped guide grooves (12) are formed at two ends of the hollow inner shaft (4), two lantern rings (14) are sleeved on the cable (13), guide pillars (15) matched with the L-shaped guide grooves (12) in a sliding mode are formed on the lantern rings (14), elastic pieces (16) matched with the limiting tables (11) in an abutting mode are arranged in the lantern rings (14), and a cable fastening mechanism is arranged inside the lantern rings (14).

10. The gear reducer for the unmanned helicopter of claim 9, wherein: the cable fastening mechanism comprises a flexible enclasping ring (17) fixedly arranged inside a lantern ring (14), a first guide surface (18) is formed on the flexible enclasping ring (17), a sliding ring (19) is arranged inside the lantern ring (14) in a sliding mode, an elastic piece (16) is fixedly arranged on the sliding ring (19), and a second guide surface (20) in butt fit with the first guide surface (18) is formed on the sliding ring (19).