阅读说明：本技术 多冗余控制的故障安全式多回转快速切断执行机构 (Fail-safe multi-turn quick-cut-off actuating mechanism with multiple redundancy controls ) 是由 田中山 赖少川 杨昌群 王永飞 赵升吨 牛道东 张晨 宋林 郭瀚泽 于 2020-03-03 设计创作，主要内容包括：本发明公开了一种多冗余控制的故障安全式多回转快速切断执行机构,包括动力机构、动力切换机构、传动系统、复位机构和多冗余安全执行机构；动力机构带动传动系统实现行程输出；动力机构包括电力驱动系统和手动操作系统；动力切换机构用于实现电力驱动系统和手动操作系统之间的切换；复位机构带动传动系统实现行程复位；多冗余安全执行机构用于当电力驱动系统、复位机构失电时对其进行代替。本发明将“交流伺服直驱”和“多冗余伺服控制”的思想应用到传统电动执行器的设计过程中去,从而简化电动执行器的结构、优化电动执行器的使用过程、提高电动执行器的工作效率、降低电动执行器的能耗,同时提升电动执行器的故障安全性。(The invention discloses a multi-redundancy control fail-safe multi-rotation quick cut-off actuating mechanism, which comprises a power mechanism, a power switching mechanism, a transmission system, a reset mechanism and a multi-redundancy safety actuating mechanism, wherein the power mechanism is connected with the power mechanism; the power mechanism drives the transmission system to realize stroke output; the power mechanism comprises an electric drive system and a manual operation system; the power switching mechanism is used for realizing switching between an electric drive system and a manual operation system; the reset mechanism drives the transmission system to realize stroke reset; the multi-redundancy safety actuating mechanism is used for replacing the electric driving system and the reset mechanism when the electric driving system and the reset mechanism are powered off. The invention applies the ideas of alternating current servo direct drive and multi-redundancy servo control to the design process of the traditional electric actuator, thereby simplifying the structure of the electric actuator, optimizing the use process of the electric actuator, improving the working efficiency of the electric actuator, reducing the energy consumption of the electric actuator and simultaneously improving the fault safety of the electric actuator.)

1. The utility model provides a many redundant control's many gyration of fail safe formula cut off actuating mechanism fast which characterized in that:

the multi-redundancy safety actuator comprises a power mechanism, a power switching mechanism, a transmission system, a reset mechanism and a multi-redundancy safety actuator;

the power mechanism drives the transmission system to realize stroke output;

the power mechanism comprises an electric drive system and a manual operation system;

the power switching mechanism is used for realizing switching between an electric drive system and a manual operation system;

the reset mechanism drives the transmission system to realize stroke reset;

the multi-redundancy safety actuating mechanism is used for replacing the electric driving system and the resetting mechanism when the electric driving system and the resetting mechanism are powered off.

2. The fail-safe, multi-turn, quick disconnect actuator of claim 1, further comprising:

the transmission mechanism comprises a worm shaft (11), a worm wheel (39) and a worm wheel shaft (40), the worm shaft (11) is meshed with the worm wheel (39), and the worm wheel (39) is arranged on the worm wheel shaft (40).

3. A multiple redundancy controlled fail-safe multiple turn quick disconnect actuator as defined in claim 2 wherein:

the electric drive system comprises a first middle stator structure disc type alternating current servo main drive motor (14), and a power output end of the first middle stator structure disc type alternating current servo main drive motor (14) is fixedly connected with the worm shaft (11);

the reset mechanism comprises a first middle stator structure disc type alternating current servo reset motor (26), and the power output end of the first middle stator structure disc type alternating current servo reset motor (26) is fixedly connected with the worm shaft (11);

the multi-redundancy safety actuating mechanism comprises a second middle stator structure disc type alternating current servo main driving motor (17) and a second middle stator structure disc type alternating current servo reset motor (29);

the power output ends of the second middle stator structure disc type alternating current servo main driving motor (17) and the second middle stator structure disc type alternating current servo reset motor (29) are fixedly connected with the worm shaft (11).

4. A multiple redundancy controlled fail-safe multiple turn quick disconnect actuator of claim 3, wherein:

the manual operation system comprises a hand wheel (1) and a speed reducer;

the speed reducer comprises a planetary gear set, the planetary gear set comprises a planetary gear set sun gear (3), planetary gear set planet pinions (5) and a planetary gear carrier (6), a hand wheel (8) is connected with the planetary gear set sun gear (3), the planetary gear set sun gear (3) is meshed with the planetary gear set planet pinions (5), and the planetary gear carrier (6) is matched with the planetary gear set planet pinions (5).

5. The fail-safe, multi-turn, quick disconnect actuator of claim 4, wherein:

the power switching mechanism comprises a clutch engaging sleeve (10) and a shifting fork (12), wherein the clutch engaging sleeve (10) is connected with a worm shaft (11) through a spline; the clutch engaging sleeve (10) can slide along the worm shaft (11) through splines, the planet gear carrier (6) can be combined with the clutch engaging sleeve (10) through the splines to transmit torque, and the shifting fork (12) is connected with the clutch engaging sleeve (10).

6. The fail-safe, multi-turn, quick disconnect actuator of claim 5, further comprising:

the worm gear brake further comprises an electromagnetic band-type brake electromagnet (32) and an electromagnetic band-type brake shoe brake (38), wherein the electromagnetic band-type brake shoe brake (38) is connected with the worm shaft (11).

7. The fail-safe, multi-turn, quick disconnect actuator of claim 6, further comprising:

the motor is characterized by further comprising a first disc type motor shell (7), a second disc type motor shell (15), a third disc type motor shell (18), a worm gear box (20), a fourth disc type motor shell (24), a fifth disc type motor shell (27) and a sixth disc type motor shell (30);

the first disc type motor shell (7) is connected with a third disc type motor shell (18) through a second disc type motor shell (15), a sixth disc type motor shell (30) is connected with a fourth disc type motor shell (24) through a fifth disc type motor shell (27), and the third disc type motor shell (18) and the fourth disc type motor shell (24) are both connected with a worm gear box (20);

the first intermediate stator structure disc type alternating current servo main driving motor (14) is arranged in a first disc type motor shell (7), the second intermediate stator structure disc type alternating current servo main driving motor (17) is arranged in a second disc type motor shell (15), the first intermediate stator structure disc type alternating current servo reset motor (26) is arranged in a fourth disc type motor shell (24),

and the second intermediate stator structure disc type alternating current servo reset motor (29) is arranged in a fifth disc type motor shell (27).

8. The fail-safe, multi-turn, quick disconnect actuator of claim 7, further comprising:

the worm wheel (39) and the worm wheel shaft (40) are arranged in the worm wheel and worm box (20).

9. The fail-safe, multi-turn, quick disconnect actuator of claim 8, further comprising:

the disc type alternating current servo main driving motor (14) with the first middle stator structure, the disc type alternating current servo main driving motor (17) with the second middle stator structure, the disc type alternating current servo reset motor (26) with the first middle stator structure and the disc type alternating current servo reset motor (29) with the second middle stator structure are completely the same in structure and comprise a disc type servo motor middle stator (49), a winding (50) and a permanent magnet group (51), wherein the winding (50) is installed on the disc type servo motor middle stator (49), and the permanent magnet group (51) is installed on a disc type servo motor rotor yoke (52).

Technical Field

The invention relates to the technical field of electric actuating mechanisms, in particular to a multi-redundancy control fault safety type multi-rotation quick cut-off actuating mechanism.

Background

With the rapid development of pipeline construction in China, the necessity of realizing the localization of key equipment of oil and gas pipelines is increasingly urgent. The localization of key equipment of the oil and gas pipeline is not only a national requirement, but also a requirement for reducing construction and operation costs of oil and gas transportation enterprises, and the localization of the key equipment of the oil and gas pipeline has important significance for reducing engineering cost, breaking monopoly and price barriers of foreign products, developing national industries and promoting the improvement of equipment levels of the oil and gas pipeline. With the increasing safety requirements in the process of automatic control of the process, especially the safety requirements of the petroleum and petrochemical system on the large-diameter valve are very urgent, and the operational reliability of the electric actuator as the terminal execution mechanism of the large-diameter valve control system will directly affect the performance level of the whole system and the system safety.

The traditional electric actuator mainly comprises a fixed shell, a motor, a speed reducer output shaft, a nut, a lead screw and a control system for controlling the motor to operate, the motor drives the speed reducer to operate through the control system, the speed reducer output shaft is connected with the lead screw, and the nut is rotated to realize straight stroke motion.

Disclosure of Invention

In order to solve the technical problems, the invention provides a multi-redundancy control fault safety type multi-rotation quick cut-off actuating mechanism, which applies the ideas of alternating current servo direct drive and multi-redundancy servo control to the design process of the traditional electric actuator, thereby simplifying the structure of the electric actuator, optimizing the use process of the electric actuator, improving the working efficiency of the electric actuator, reducing the energy consumption of the electric actuator and simultaneously improving the fault safety of the electric actuator.

The technical scheme for solving the problems is as follows: a fail-safe multi-turn quick-cut-off actuating mechanism with multiple redundancy controls is characterized in that:

the multi-redundancy safety actuator comprises a power mechanism, a power switching mechanism, a transmission system, a reset mechanism and a multi-redundancy safety actuator;

the power mechanism drives the transmission system to realize stroke output;

the power mechanism comprises an electric drive system and a manual operation system;

the power switching mechanism is used for realizing switching between an electric drive system and a manual operation system;

the reset mechanism drives the transmission system to realize stroke reset;

the multi-redundancy safety actuating mechanism is used for replacing the electric driving system and the resetting mechanism when the electric driving system and the resetting mechanism are powered off.

Furthermore, the transmission mechanism comprises a worm shaft, a worm wheel and a worm wheel shaft, wherein the worm shaft is meshed with the worm wheel, and the worm wheel is arranged on the worm wheel shaft.

Furthermore, the electric drive system comprises a first intermediate stator structure disc type alternating current servo main drive motor, and a power output end of the first intermediate stator structure disc type alternating current servo main drive motor is fixedly connected with the worm shaft.

The reset mechanism comprises a first middle stator structure disc type alternating current servo reset motor, and a power output end of the first middle stator structure disc type alternating current servo reset motor is fixedly connected with the worm shaft;

the multi-redundancy safety actuating mechanism comprises a second middle stator structure disc type alternating current servo main driving motor and a second middle stator structure disc type alternating current servo reset motor;

and the power output ends of the second intermediate stator structure disc type alternating current servo main driving motor and the second intermediate stator structure disc type alternating current servo reset motor are fixedly connected with the worm shaft.

Further, the manual operating system comprises a hand wheel and a speed reducer;

the speed reducer comprises a planetary gear set, the planetary gear set comprises a planetary gear set sun gear, planetary gear set planetary pinions and a planetary gear carrier, a hand wheel is connected with the planetary gear set sun gear, the planetary gear set sun gear is meshed with the planetary gears of the planetary gear set, and the planetary gear carrier is matched with the planetary pinions of the planetary gear set.

Furthermore, the power switching mechanism comprises a clutch engaging sleeve and a shifting fork, wherein the clutch engaging sleeve is connected with the worm shaft through a spline; the clutch engaging sleeve can slide along the worm shaft through a spline, the planet carrier can be combined with the clutch engaging sleeve through the spline to transmit torque, and the shifting fork is connected with the clutch engaging sleeve.

Further, the electromagnetic band-type brake further comprises an electromagnetic band-type brake braking electromagnet and an electromagnetic band-type brake shoe brake, wherein the electromagnetic band-type brake shoe brake is connected with the worm shaft.

The motor further comprises a first disc type motor shell, a second disc type motor shell, a third disc type motor shell, a worm gear box, a fourth disc type motor shell, a fifth disc type motor shell and a sixth disc type motor shell;

the first disc type motor shell is connected with the third disc type motor shell through the second disc type motor shell, the sixth disc type motor shell is connected with the fourth disc type motor shell through the fifth disc type motor shell, and the third disc type motor shell and the fourth disc type motor shell are both connected with the worm gear box;

the first intermediate stator structure disc type alternating current servo main driving motor is arranged in a first disc type motor shell, the second intermediate stator structure disc type alternating current servo main driving motor is arranged in a second disc type motor shell, the first intermediate stator structure disc type alternating current servo reset motor is arranged in a fourth disc type motor shell, and the second intermediate stator structure disc type alternating current servo reset motor is arranged in a fifth disc type motor shell.

Further, the worm wheel and the worm wheel shaft are arranged in the worm wheel and worm box.

Further, the first intermediate stator structure disc type alternating current servo main driving motor, the second intermediate stator structure disc type alternating current servo main driving motor, the first intermediate stator structure disc type alternating current servo reset motor and the second intermediate stator structure disc type alternating current servo reset motor are completely the same in structure and comprise a disc type servo motor intermediate stator, a winding and a permanent magnet group, wherein the winding is installed on the disc type servo motor intermediate stator, and the permanent magnet group is installed on a disc type servo motor rotor yoke.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention uses a multi-redundancy servo control technology, and under the condition that a valve connected with the mechanism is opened, if a first middle stator structure disc type alternating current servo main driving motor or a first middle stator structure disc type alternating current servo reset motor fails due to an accident or other reasons, a second middle stator structure disc type alternating current servo main driving motor or a second middle stator structure disc type alternating current servo reset motor receives signal substitution work, so that casualties and property loss caused by accidents are avoided;

(2) the invention uses the disk type AC servo motor with the middle stator structure, the motor has compact structure, short axial size and small occupied volume, the motor adopts an iron-cored armature structure, the torque pulsation caused by tooth grooves of a common cylindrical motor is avoided, the torque output is stable, the motor has no hysteresis lag and eddy current loss, higher efficiency can be achieved, energy is saved, the inductance of a motor winding is small, and the motor has good reversing performance, two end surfaces of the motor winding are in contact with air gaps, heat dissipation is facilitated, the motor is in AC servo drive, the speed can be adjusted directly, and a complicated speed reducing mechanism is avoided;

(3) the invention designs the clutch to realize automatic and manual gear control, when the clutch is shifted to the right, the worm is only connected with the motor, at the moment, the clutch is electrically controlled, when the motor is powered off or is not powered on, the hand wheel and the planetary gear set can be connected with the nut by shifting the clutch to the left, thereby realizing manual control, and the adoption of the planetary gear set can save labor.

Drawings

Fig. 1 is a schematic front view of the present invention.

Fig. 2 is a schematic structural diagram of the front side of the hand wheel and the planetary reducer of the invention.

Fig. 3 is a front sectional view of the worm shaft of the present invention.

Figure 4 is a front cross-sectional view of the worm gear shaft of the present invention.

Fig. 5 is a front sectional view of a disc type ac servo motor of an intermediate stator structure according to the present invention.

The reference numbers in the figures illustrate: 1. a hand wheel, 2, a planet gear left end cover, 3, a planet gear set sun gear, 4, a first deep groove ball bearing, 5, a planet gear set planet pinion, 6, a planet gear carrier, 7, a first disk type motor shell, 8, a second deep groove ball bearing, 9, a first bolt group, 10, a clutch engaging sleeve, 11, a worm shaft, 12, a shifting fork, 13, a third deep groove ball bearing, 14, a first intermediate stator structure disk type alternating current servo main driving motor, 15, a second disk type motor shell, 16, a second bolt group, 17, a second intermediate stator structure disk type alternating current servo main driving motor, 18, a third disk type motor shell, 19, a third bolt group, 20, a worm gear box, 21, a fourth bolt group, 22, a fourth deep groove ball bearing, 23, a fifth deep groove ball bearing, 24, a fourth disk type motor shell, 25, a fifth bolt group, 26, a first intermediate stator structure disk type alternating current servo reset motor, 27. a fifth disk type motor housing, 28, a sixth bolt group, 29, a second intermediate stator structure disk type alternating current servo reset motor, 30, a sixth disk type motor housing, 31, a seventh bolt group, 32, an electromagnetic band-type brake electromagnet, 33, a disk type motor end cover, 34, an eighth bolt group, 35, a sixth deep groove ball bearing, 36, a ninth bolt group, 37, a first bearing end cover, 38, an electromagnetic band-type brake shoe brake, 39, a worm wheel, 40, a worm wheel shaft, 41, a flat key, 42, a seventh deep groove ball bearing, 43, a shaft sleeve, 44, a worm wheel and worm box top cover, 45, a ninth bolt group, 46, an eighth deep groove ball bearing, 47, a tenth bolt group, 48, a second bearing end cover, 49, a disk type servo motor intermediate stator, 50, a winding, 51, a permanent magnet group, 52 and a disk type servo motor rotor yoke.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.

As shown in fig. 1, 2 and 3, the multiple redundancy control fail-safe multi-turn quick-cut-off actuator includes a hand wheel 1 connected to a planetary gear set sun gear 3 through a planetary gear left end cap 2, the hand wheel 1 connected to the planetary gear left end cap 2 through a first deep groove ball bearing 4, the planetary gear set sun gear 3 meshed with a planetary gear set planetary pinion 5, a planetary gear carrier 6 meshed with the planetary gear set planetary pinion 5, the planetary gear carrier 6 connected to a first disk motor housing 7 through a second deep groove ball bearing 8, the first disk motor housing 7 connected to the planetary gear left end cap 2 through a first bolt set 9, a clutch engaging sleeve 10 connected to a worm shaft 11, and the planetary gear carrier 6 connected to each other through a spline, a shift fork 12 connected to the clutch engaging sleeve 10, and a shift fork 12 connected to the first disk motor housing 7, the first disc motor housing 7 and the worm shaft 11 are coupled by a third deep groove ball bearing 13.

As shown in fig. 1 and fig. 3, a first intermediate stator structure disc ac servo main driving motor 14 is installed in the first disc motor housing 7, and the first intermediate stator structure disc ac servo main driving motor 14 is fixedly connected to the worm shaft 11. The first disc type motor shell 7, the first intermediate stator structure disc type alternating current servo main driving motor 14 and the second disc type motor shell 15 are connected through a second bolt group 16.

As shown in fig. 1 and fig. 3, a second intermediate stator structure disc ac servo main driving motor 17 is installed in the second disc motor housing 15, and the second intermediate stator structure disc ac servo main driving motor 17 is fixedly connected to the worm shaft 11. The second disk type motor shell 15, the second intermediate stator structure disk type alternating current servo main driving motor 17 and the third disk type motor shell 18 are connected through a third bolt group 19. The worm and gear box 20 is connected with the third disc type motor shell 18 through a fourth bolt group 21, the worm and gear box 20 is connected with the worm shaft 11 through a fourth deep groove ball bearing 22 and a fifth deep groove ball bearing 23, the worm and gear box 20 is connected with a fourth disc type motor shell 24 through a fifth bolt group 25, and the worm gear are meshed with the worm shaft 11.

As shown in fig. 1 and fig. 3, a first intermediate stator structure disc ac servo reset motor 26 is installed in the fourth disc motor housing 24, and the first intermediate stator structure disc ac servo reset motor 26 is fixedly connected to the worm shaft 11. The fourth disc type motor shell 24, the first intermediate stator structure disc type alternating current servo reset motor 26 and the fifth disc type motor shell 27 are connected through a sixth bolt group 28.

As shown in fig. 1 and 3, a second intermediate stator structure disc ac servo reset motor 29 is installed in the fifth disc motor housing 27, and the second intermediate stator structure disc ac servo reset motor 29 is fixedly connected to the worm shaft 11. The fifth disc type motor shell 27, the second intermediate stator structure disc type alternating current servo reset motor 29 and the sixth disc type motor shell 30 are connected through a seventh bolt group 31.

As shown in fig. 1, 3 and 4, the sixth disk motor housing 30, the electromagnetic band-type brake electromagnet 32 and the disk motor end cover 33 are coupled by an eighth bolt group 34, the sixth disk motor housing 30 is coupled with the worm shaft 11 by a sixth deep groove ball bearing 35, the sixth disk motor housing 30 is coupled with a first bearing end cover 37 by a ninth bolt group 36, and the electromagnetic band-type brake shoe brake 38 and the worm shaft 11 are tightly fitted. The worm wheel 39 is meshed with the worm shaft 11, the worm wheel 39 is connected with the worm wheel shaft 40 through a flat key 41, the worm wheel shaft 40 is connected with a worm wheel and worm box top cover 44 through a seventh deep groove ball bearing 42, the worm wheel 39 and a shaft shoulder of the worm wheel shaft 40 form axial positioning through a shaft sleeve 43, the worm wheel and worm box top cover 44 is connected with the worm wheel and worm box 20 through a ninth bolt group 45, the worm wheel shaft 40 is connected with the worm wheel and worm box 20 through an eighth deep groove ball bearing 46, and the worm wheel and worm box 20 is connected with a second bearing end cover 48 through a tenth bolt group 47.

As shown in fig. 1, fig. 3 and fig. 5, the first intermediate stator structure disc type ac servo main driving motor 14, the second intermediate stator structure disc type ac servo main driving motor 17, the first intermediate stator structure disc type ac servo reset motor 26 and the second intermediate stator structure disc type ac servo reset motor 29 have the same structure, and mainly include a disc type servo motor intermediate stator 49, a winding 50 mounted on the disc type servo motor intermediate stator 49, and a permanent magnet group 51 mounted on a disc type servo motor rotor yoke 52.

The working principle of the invention is as follows:

(1) the specific principle that the worm wheel shaft is driven to rotate by the first middle stator structure disc type alternating current servo main driving motor 14, the second middle stator structure disc type alternating current servo main driving motor 17, the first middle stator structure disc type alternating current servo reset motor 26 and the second middle stator structure disc type alternating current servo reset motor 29 is as follows:

by energizing the winding 50 of the disc-type servo motor intermediate stator 49, the disc-type servo motor rotor yoke 52 is rotated after the energization of the winding 50 of the disc-type servo motor intermediate stator 49, so as to drive the worm shaft 11 to rotate synchronously, and further drive the worm wheel 39 meshed with the worm shaft, and the worm wheel 39 drives the worm shaft 40 connected with the worm shaft in a key manner. When the first intermediate stator structure disc type alternating current servo main driving motor 14, the second intermediate stator structure disc type alternating current servo main driving motor 17, the first intermediate stator structure disc type alternating current servo reset motor 26 and the second intermediate stator structure disc type alternating current servo reset motor 29 drive the worm shaft 11, the worm wheel 39 and the worm wheel shaft 40 to move, the electromagnetic band-type brake electromagnet 32 is powered off and separated from the electromagnetic band-type brake shoe brake 38, when the first intermediate stator structure disc type alternating current servo main driving motor 14, the second intermediate stator structure disc type alternating current servo main driving motor 17, the first intermediate stator structure disc type alternating current servo reset motor 26 and the second intermediate stator structure disc type alternating current servo reset motor 29 stop moving, the electromagnetic band-type brake electromagnet 32 is powered on and is in band-type with the electromagnetic band-type brake shoe brake 38, the worm shaft 11 and the electromagnetic band-type brake shoe brake 38 stop rotating together, thereby effecting worm shaft 40 braking.

(2) The invention adopts the specific principle that the multi-redundancy servo control realizes the fault safety as follows:

when the first intermediate stator structure disc type alternating current servo main driving motor 14 and the first intermediate stator structure disc type alternating current servo reset motor 26 are failed due to an accident or other reasons, the second intermediate stator structure disc type alternating current servo main driving motor 17 and the second intermediate stator structure disc type alternating current servo reset motor 29 start to work, and therefore the failure safety is achieved.

(3) The specific principle of the automatic gear switching and the manual gear switching is as follows:

when the shifting fork 12 is positioned to the left, the clutch joint sleeve 10 is only connected with the worm shaft 11 through a spline, the worm shaft 11 rotates to drive the worm shaft 11, the gear is controlled by a motor at the moment, when the electromagnetic band-type brake electromagnet 32 is de-energized, the shifting fork 12 is moved upwards, so that the manual control mode is switched, at the moment, the hand wheel 1 is rotated, the hand wheel 1 drives the planetary gear set sun gear 3 to rotate, the planetary gear set sun gear 3 drives the planetary gear set planetary pinion 5 to rotate, the planetary gear set planetary pinion 5 drives the planetary gear carrier 6 to rotate, the planetary gear carrier 6 is connected with the clutch joint sleeve 10 through a spline, the clutch joint sleeve 10 is connected with the worm shaft 11 through a spline, the worm shaft 11 rotates to drive the worm wheel 39 and the worm wheel shaft 40 to rotate, and therefore.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structures or equivalent flow transformations made by using the contents of the specification and the drawings, or applied directly or indirectly to other related systems, are included in the scope of the present invention.