Power device and control method for an electrically driven rotary cultivator

Abstract

The application discloses a power device and a control method of an electric rotary cultivator, and relates to the technical field of farming equipment. The power device comprises a walking power module, a power distribution module, a wheel edge reduction module, a locking execution assembly and a steering transmission module. The wheel edge reduction module comprises a first-stage planetary reduction mechanism. The first-stage planetary reduction mechanism is provided with a transmission gear ring. The transmission gear ring comprises an inner gear ring and an outer gear ring. The steering transmission module comprises a steering motor and a steering reduction chain. The steering reduction chain comprises a plurality of steering transmission units. Each steering transmission unit comprises two reversing gears. The rotating directions of the two reversing gears are opposite. The reversing gears are engaged with the outer gear ring of the transmission gear ring, so that the transmission gear rings on both sides rotate in opposite directions. The locking execution assembly comprises a locking disc and a locking unit. The locking unit clamps the locking disc, thereby forcing the transmission gear ring to stop rotating, so that the output half shafts on both sides are rigidly connected, and the steering reduction chain is synchronously locked under extreme working conditions.

Description

Technical Field

[0001] This invention relates to the field of agricultural equipment technology, specifically to a power unit and control method for an electric rotary tiller. Background Technology

[0002] Currently, traditional tracked tractors mostly use single-sided braking steering, which has a large turning radius, making driving inconvenient, especially in small fields and village roads. When traveling straight, the braking system needs to be constantly engaged, requiring frequent brake maintenance and replacement. Steering also requires the braking system to work in conjunction, and switching from steering mode requires stopping and restarting, resulting in complex control logic. Any misalignment can increase abnormal wear on mechanical components. When traveling straight, if there is a significant difference in load between the left and right tracks, the braking system can slip, causing uneven output speeds on both tracks, leading to mis-steering and wobbling during travel.

[0003] To address the aforementioned issues, Chinese invention patent application number 202411615872.9 discloses an active differential steering drive for tracked vehicles, comprising a housing, a main shaft, a first output half-shaft, a first planetary gear mechanism, a second output half-shaft, a second planetary gear mechanism, a steering input shaft, a first worm, a second worm, and a power input shaft. This design inputs power through the steering input shaft, which is then transmitted to the first and second worms via the gear set. The first and second worms mesh with the first and second worm gear teeth, respectively. The self-locking characteristic of the worm gears keeps the first gear ring stationary during straight-line travel. When turning is required, power is input through the steering input shaft, causing the first gear rings of the left and right first-stage planetary reduction mechanisms to rotate in opposite directions, achieving differential steering. This design eliminates traditional brake locking and friction braking devices.

[0004] However, the above solution still has the following shortcomings in practical applications: In this design, the self-locking action of the worm gear occurs at a single meshing point between the worm and the worm wheel teeth, which is a localized point locking. The locking force acts only on the first gear ring component, resulting in a short and concentrated locking path. When an external torque (such as the impact load generated when one wheel completely slips) acts on the first gear ring, this impact load is directly applied to the meshing surface of the worm gear, without any other transmission components to share or buffer it. This localized point locking method makes the locking capability entirely dependent on the performance of the worm gear friction pair, lacking redundancy and hierarchical protection. Secondly, the self-locking mechanism of worm gears is essentially frictional self-locking, with the locking force originating from the static friction between the worm wheel and the worm. When the external torque exceeds this threshold, the self-locking mechanism risks failure, and the worm wheel can reverse the direction of the worm. Under extreme conditions (such as simultaneous slippage of both wheels, complete suspension of a single wheel, or starting on a slope), when the external torque exceeds the self-locking threshold, the locking fails, and the rigid synchronization of the output half-shafts on both sides cannot be guaranteed.

[0005] Furthermore, when the external torque exceeds the self-locking threshold of the worm gear, the first gear ring rotates. This rotation drives the worm gear in the opposite direction, which in turn drives the steering input shaft to rotate. Unexpected rotation of the steering input shaft may cause malfunctions in the steering system, resulting in a sudden change in the vehicle's direction of travel, posing a safety hazard.

[0006] In extreme conditions requiring forced locking, this solution can only rely on the worm gear self-locking to maintain the stationary position of the first gear ring, while the steering input shaft remains free. Once the self-locking is broken, not only will the locking fail, but the steering system will also be reverse-driven, exacerbating the difficulty of getting out of trouble. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a power device and control method for an electric rotary tiller to ensure that the steering reduction chain locks synchronously under extreme working conditions.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a power unit for an electric rotary tiller, installed at the bottom of the chassis of an agricultural vehicle, comprising: The walking power module includes a walking motor for providing walking power, and a continuously variable transmission mechanism disposed on the output end of the walking motor, wherein a power input shaft is provided on the output end of the continuously variable transmission mechanism; The power distribution module includes a main reduction gear that is driven to the power input shaft, and a bridge main shaft that is driven to the main reduction gear. Wheel-side reduction modules are connected to both ends of the bridge main shaft; each wheel-side reduction module includes at least one planetary reduction mechanism, and the actuating end of the first-stage planetary reduction mechanism is connected to an output half shaft; the first-stage planetary reduction mechanism has a transmission gear ring, which includes an inner gear ring for constructing the planetary transmission system and an outer gear ring disposed on the outer periphery of the transmission gear ring. A steering transmission module includes a steering motor that provides steering power and a steering reduction chain that receives steering power. The steering reduction chain includes multiple meshing steering transmission units. Each steering transmission unit includes two reversing gears located at the end of the steering reduction chain. The two reversing gears rotate in opposite directions. The reversing gears mesh with the outer gear ring of the transmission gear ring so that the two sides of the transmission gear ring rotate in opposite directions. The locking actuator includes a locking disc and a locking unit for applying a braking force to the locking disc. The locking disc is located on a component in the steering reduction chain that can rotate synchronously with the steering motor's actuating end. The locking unit holds the locking disc by the braking force, thereby forcing the transmission gear ring to stop rotating, so that the output half shafts on both sides are rigidly connected.

[0009] By utilizing the meshing transmission relationship of each steering transmission unit in the steering reduction chain, the braking force is transmitted to the end reversing gear, forcing the transmission gear rings on both sides to stop rotating simultaneously. Because multiple transmission units share the braking force, the locking force is distributed along the steering reduction chain, no longer limited to a single meshing point, thus avoiding the problem of insufficient locking capacity caused by local point locking.

[0010] Furthermore, the steering reduction chain includes a steering output shaft, a steering drive shaft, a rotation conversion transmission pair, and two side drive shafts, with multiple steering transmission units driven between the steering output shaft and the steering drive shaft; the steering output shaft is located on the actuating end of the steering motor; The input end of the rotation direction conversion transmission pair is connected to the steering drive shaft, and the two output ends of the rotation direction conversion transmission pair are respectively connected to the two side drive shafts. The rotation directions of the output ends of the rotation direction conversion transmission pair are opposite. The reversing gear is located on the side drive shaft. Through the above improvements, by setting the rotation direction conversion transmission pair, the unidirectional rotation of the steering drive shaft can be converted into the opposite rotation of the two side drive shafts, thereby driving the two transmission gear rings to rotate in opposite directions, realizing differential steering and stationary steering.

[0011] Furthermore, the steering transmission unit includes a steering drive wheel on the steering output shaft and a steering driven wheel on the steering transmission shaft. At least one steering reduction wheel meshes between the steering drive wheel and the steering driven wheel. Through the above improvements, by setting the steering reduction wheel, the power output by the steering motor is transmitted to the steering transmission shaft through a multi-stage gear pair, and then diverted to the two side transmission shafts by the rotational conversion transmission pair, and finally drives the reversing gear to drive the two side transmission gear rings to rotate in opposite directions.

[0012] Furthermore, the rotation direction conversion transmission pair includes a first bevel gear disposed at the end of the steering transmission shaft and a second bevel gear disposed on the side transmission shaft. The two second bevel gears are symmetrically disposed on both sides of the axis of the first bevel gear and rotate in opposite directions. Through the above improvement, since the two second bevel gears are located on both sides of the first bevel gear and form a symmetrical arrangement with opposite meshing transmission directions, under the meshing drive of the two second bevel gears, the two side transmission shafts obtain rotational motion in opposite directions, thereby driving the reversing gear to drive the transmission gear rings on both sides to rotate in opposite directions, realizing differential steering, shortening the power transmission path, and improving transmission efficiency.

[0013] Furthermore, the locking disc is coaxially disposed at the bottom of the steering output shaft or the steering transmission shaft. By placing the locking disc at the bottom of the steering output shaft or the steering transmission shaft, the entire steering reduction chain can be locked when locked, achieving synchronous locking of the steering mechanism. The locking execution component is integrated into the lower space of the input end of the steering reduction chain, without occupying additional space on the side or top of the transmission system. It can form an axial stacked layout with the steering motor and transmission wheel system, significantly reducing the lateral dimension of the steering transmission module and adapting to the overall design requirements of a flat bottom for the power unit.

[0014] Furthermore, the wheel-side reduction module also includes a two-stage planetary reduction mechanism. The planet carrier of the first-stage planetary reduction mechanism is connected to the sun gear of the second-stage planetary reduction mechanism, and the planet carrier of the second-stage planetary reduction mechanism is connected to the output half shaft. The two-stage planetary reduction can achieve a larger reduction ratio to meet the high torque output requirements of agricultural vehicles.

[0015] Furthermore, the continuously variable transmission (CVT) is equipped with a gear shifting mechanism and a braking mechanism. The gear shifting mechanism can switch between forward, neutral, and reverse gears, while the braking mechanism can brake the driving force in parking or emergency situations, thereby improving the vehicle's operational convenience and safety.

[0016] Furthermore, the two side drive shafts are coaxial and opposite to each other, and are arranged parallel to each other at the lower part of the output half shaft axis. The steering drive shaft is arranged parallel to the steering output shaft and extends vertically at the lower part of the output half shaft axis. The steering motor is coaxial with the steering output shaft and extends toward the axis of the output half shaft. Multiple steering transmission units are arranged in a coplanar manner to achieve a compact spatial layout of the steering transmission module, making the steering transmission module as a whole flat, which is beneficial to reducing the height of the power unit and adapting to the installation space at the bottom of the chassis.

[0017] Through the above improvements, the entire steering transmission module is arranged in the lower space below the output half shaft axis, forming a layered layout with the continuously variable transmission mechanism above. This avoids spatial interference between the steering transmission and the travel power transmission, significantly reduces the longitudinal height of the power unit, and ensures that the bottom is flat. At the same time, the coplanar arrangement of the steering transmission unit ensures that all gear pairs are on the same mounting plane.

[0018] Furthermore, the power input shaft extends vertically to the middle of the axis of the output half shafts on both sides and is set away from the steering transmission module. The continuously variable transmission mechanism extends in the same direction as the steering reduction chain, and the walking motor and the steering motor are arranged parallel to and opposite to each other, so that the walking power path and the steering power path are independent of each other and do not interfere with each other. At the same time, the center of gravity of the whole machine is in the middle, which is beneficial to the driving stability of the vehicle.

[0019] The present invention also provides a control method for the power unit of an electric rotary tiller, applied to the aforementioned power unit of the electric rotary tiller, comprising the following steps: Obtain vehicle operating status information, including the speed of the travel motor, the speed of the steering motor, and the speed difference or torque difference between the two output half shafts; Based on the operating status information, the current operating mode of the vehicle is determined. The operating mode includes straight driving mode, differential steering mode, stationary steering mode and forced locking mode. When the vehicle is determined to be in forced locking mode, the locking actuator is activated, causing the locking unit to apply braking force to the locking disc. The locking disc stops rotating, and through the linkage of the steering reduction chain, the reversing gear stops rotating, which in turn stops the transmission gear ring. The output half shafts on both sides output the same speed and torque, while the steering motor is forced to stop due to the locking of the steering reduction chain.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention features a coaxial locking disc on one of the moving components in the steering reduction chain. The locking disc locks the agricultural vehicle under extreme operating conditions, preventing rotation. This locks the steering reduction chain from the steering output shaft to the reversing gear, thus locking the transmission gear ring and simultaneously locking the steering reduction chain. At this point, the output half-shafts on both sides are rigidly connected, forcing them to operate with the same torque and speed, ensuring traction under extreme conditions. Simultaneously, the steering transmission module stops rotating, preventing the steering reduction chain from being reverse-driven when external force breaks the lock, thus preventing wheel or track slippage and worsening of ruts, and improving safety and reliability.

[0021] The deceleration transmission chain of the present invention uses multiple steering transmission units to drive or stop the transmission gear ring through mutual linkage. Starting from the steering output shaft, the locking path is longer, and the locking force is shared by multiple steering transmission units, resulting in higher reliability. At the same time, the locking disc can apply braking force through the locking unit. This braking force can be selected as surface clamping or geometric interference limiting to ensure locking stability and avoid steering operations under extreme conditions.

[0022] Furthermore, this invention adds a continuously variable transmission mechanism to the output end of the walking motor, which can achieve gear shifting and stepless speed change without interrupting power during operation. This ensures that the motor always works in the high-efficiency range, preventing the motor from overheating due to overload or excessive speed, thereby reducing power consumption.

[0023] Simultaneously, by adjusting the speed ratio of the steering motor and the travel motor, the turning arc of the vehicle can be controlled, allowing the wheels or tracks to turn close to the edge. This control method enables precise control of both differential steering and on-the-spot steering, thereby controlling the steering angle of agricultural machinery vehicles, making steering more continuous, and achieving continuous steering at any angle.

[0024] In addition, the main reduction transmission unit, bridge main shaft, wheel-side reduction unit, steering reduction chain, etc. of the present invention all adopt constant mesh transmission, without sliding elements, which reduces losses, improves reliability, eliminates the need for frequent maintenance, reduces wheel or track wear during steering and driving, and ensures that the wheels or tracks on both sides always maintain output, reducing the possibility of getting stuck and making full use of power. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the steering transmission module of the present invention; Figure 5 For the present invention Figure 4 Enlarged view of point B in the middle; Figure 6 This is a cross-sectional view of the present invention; In the diagram: 1. Walking motor; 2. Continuously variable transmission (CVT); 21. Power input shaft; 22. Gear shifting mechanism; 23. Braking mechanism; 3. Main reduction pair; 31. Driving bevel gear; 32. Driven bevel gear; 4. Bridge main shaft; 5. Wheel-side reduction module; 51. First-stage planetary reduction mechanism; 511. Transmission gear ring; 512. External gear ring; 52. Second-stage planetary reduction mechanism; 6. Output half shaft; 7. Steering motor; 8. Steering reduction chain; 81. Steering output shaft; 82. Steering transmission shaft; 83. Rotation direction conversion transmission pair; 831. First bevel gear; 832. Second bevel gear; 84. Side transmission shaft; 85. Reversing gear; 86. Steering driving wheel; 87. Steering driven wheel; 88. Steering reduction wheel; 9. Locking actuator; 91. Locking disc; 92. Locking unit; 10. Main housing; 11. Steering transmission housing; 12. Gearbox housing. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be understood that although the terms upper, middle, lower, top, one end, etc., appear in this document to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish the elements from each other for ease of understanding, and are not used to define any directional or sequential restrictions.

[0028] like Figures 1 to 6 As shown, a power unit for an electric rotary tiller, as an independent power pack, is installed at the bottom of the chassis of the agricultural vehicle, including: The walking power module includes a walking motor 1 for providing walking power, and a continuously variable transmission mechanism 2 set on the output end of the walking motor 1. The output of the continuously variable transmission mechanism 2 is provided with a power input shaft 21, and the walking power is output to the output half shafts 6 on both sides of the axis through the continuously variable transmission mechanism 2. The power distribution module includes a main reduction pair 3 that is driven and connected to the power input shaft 21, and a bridge main shaft 4 that is driven and connected to the main reduction pair 3. The bridge main shaft 4 is coaxially arranged with the output half shaft 6 and transmits power. Wheel-side reduction modules 5 are connected to both ends of the bridge main shaft 4. Each wheel-side reduction module 5 includes at least one planetary reduction mechanism 51. The actuating end of the first-stage planetary reduction mechanism 51 is connected to the output half shaft 6. The first-stage planetary reduction mechanism 51 has a transmission gear ring 511. The transmission gear ring 511 includes an inner gear ring for constructing the planetary transmission system and an outer gear ring 512 located on the outer periphery of the transmission gear ring 511. The outer gear ring 512 can be integrally formed on the outer periphery of the inner gear ring or connected by mechanical fixing. Thus, from the walking motor 1, the continuously variable transmission mechanism 2, the power input shaft, the main reduction pair 3 and the bridge main shaft 4, to the wheel-side reduction modules 5 and the output half shaft 6 on both sides of the axis, a positive walking power chain is formed. The steering transmission module includes a steering motor 7 that provides steering power and a steering reduction chain 8 that receives steering power. The steering reduction chain 8 includes multiple meshing steering transmission units. Each steering transmission unit includes two reversing gears 85 located at the end of the steering reduction chain 8. The two reversing gears 85 rotate in opposite directions. The reversing gears 85 mesh with the outer gear ring 512 of the transmission gear ring 511 so that the two transmission gear rings 511 on both sides rotate in opposite directions. The two reversing gears 85 are synchronously connected to the same stage steering transmission unit in the preceding sequence so as to synchronously rotate in opposite directions, thereby driving the transmission gear ring 511 corresponding to the output half shaft 6 to generate additional rotation in opposite directions, so as to realize the steering or turning around of the agricultural machinery. The locking actuator 9 includes a locking disc 91 and a locking unit 92 for applying braking force to the locking disc 91. The locking disc 91 is located on a component in the steering reduction chain 8 that can rotate synchronously with the actuating end of the steering motor 7. That is, the locking disc 91 is located on the first-stage steering transmission unit in the steering reduction chain 8. The locking unit 92 holds the locking disc 91 by the braking force, thereby forcing the steering reduction chain 8 to interrupt transmission. At this time, the transmission gear ring 511 stops rotating, so that the output half shafts 6 on both sides are rigidly connected. The output half shafts 6 on both sides cannot generate a speed difference, so as to maintain the same speed and torque.

[0029] In this embodiment, by setting a continuously variable transmission mechanism 2 between the walking motor 1 and the power distribution module, the gear is automatically matched according to the load, and continuous speed change can be achieved without interrupting the power, which improves the work efficiency and driving comfort. Thus, the walking motor always works in the high-efficiency range, preventing the walking motor from overheating due to overload or excessive speed, thereby reducing power consumption and realizing full power shifting and continuously variable transmission.

[0030] Furthermore, the continuously variable transmission mechanism 2 is a CVT gearbox. CVT gearboxes have a mature structure, smooth transmission, and are suitable for the high-load operating conditions of agricultural vehicles.

[0031] Further reference Figure 1 In some embodiments, the continuously variable transmission 2 is equipped with a gear shifting mechanism 22 and a braking mechanism 23. The gear shifting mechanism 22 can switch between forward gear, neutral gear and reverse gear, and the braking mechanism 23 can brake the driving force in parking or emergency situations, thereby improving the vehicle's operational convenience and safety.

[0032] In the above embodiments, the CVT transmission, as well as the gear shifting mechanism 22 and the braking mechanism 23 thereon, are all mature technologies in the field, and will not be described in detail here.

[0033] As an explanation for steering by wheels or tracks: Taking a right turn as an example, firstly, the locking actuator 9 releases the locking disc 91, and outputs steering force through the steering motor 7 and steering reduction chain 8. An additional rotation is applied to the left transmission gear ring 511 in the same direction as the driving force, increasing the speed of the left gear ring and consequently increasing the speed of the left planetary carrier, thus accelerating the speed of the left output half-shaft 6. Conversely, an additional rotation is applied to the right transmission gear ring 511 in the opposite direction to the driving force, decreasing the speed of the right gear ring and consequently decreasing the speed of the right planetary carrier, thus slowing down the speed of the right output half-shaft 6. This creates a speed difference between the two output half-shafts 6, causing the vehicle to turn towards the side with the slower speed. By adjusting the speed ratio between the steering motor 7 and the travel motor 1, the speed difference between the output half-shafts 6 on both sides can be precisely controlled. At this time, the travel motor 1 still outputs power, which can realize large-angle steering of the wheels or tracks.

[0034] Furthermore, based on the curvature of the curve boundary, the output ratio of the steering motor 7 and the output ratio of the travel motor 1 are adjusted according to a preset ratio to achieve a specific turning arc, thereby enabling the vehicle to conform to the curve boundary and reduce track wear.

[0035] As an explanation for turning around on the spot using wheels or tracks: When the vehicle needs to make a U-turn, the travel motor 1 does not start, only the steering motor 7 starts. The power output by the steering motor 7 is transmitted to the reversing gears 85 on both sides via the steering reduction chain 8. Since the two reversing gears 85 rotate in opposite directions, the outer gear rings 512 of the transmission gear rings 511 on both sides are driven to produce rotations of equal magnitude but opposite directions.

[0036] At this time, there is no power input in the walking power chain, that is, the speed of the planet carrier in the planetary transmission system is proportional to the speed of the transmission ring gear 511. Since the speeds of the transmission ring gears 511 on both sides are equal in magnitude and opposite in direction, the speeds of the planet carriers on both sides are also equal in magnitude and opposite in direction. After being transmitted to the output half shaft 6 by the end planet carrier of the planetary transmission system, the output half shafts 6 on both sides obtain speeds of equal magnitude and opposite in direction, driving the wheels or tracks on both sides of the vehicle to move in opposite directions at the same speed, thereby realizing the vehicle turning around its own center point in place.

[0037] This on-the-spot U-turn method requires no braking assistance and has no turning radius limitation. It can turn in narrow fields or at the end of fields, significantly improving the maneuverability and flexibility of agricultural vehicles in small field operations.

[0038] In this embodiment, under extreme operating conditions, the steering reduction chain 8 is stopped from rotating by the locking actuator. After the locking disc 91 is engaged, the steering transmission unit coaxially connected to it first stops rotating. Since all levels of the steering transmission units in the steering reduction chain 8 are in constant mesh, the stop constraint is transmitted step by step along the meshing path, sequentially through the steering transmission shaft 82, the rotation direction conversion transmission pair 83, and the side transmission shaft 84 to the two reversing gears 85, so that the two reversing gears 85 are locked simultaneously. Then, through the meshing relationship between the external gear ring 512 and the reversing gear 85, the two transmission gear rings 511 are locked synchronously. In this state, the transmission gear ring 511 is fixed relative to the main housing 10. After the traveling power is input through the main reduction pair 3 and the bridge main shaft 4, it can only be output to the output half shaft 6 through a single path of the planetary carrier. The two output half shafts 6 thus obtain exactly the same speed and torque, achieving mechanical rigid synchronization.

[0039] Preferably, the locking disc 91 is positioned at the input end of the steering reduction chain 8. The locking force is distributed and borne through the meshing surfaces of the multi-stage steering transmission unit. Even if the external torque acts on the transmission gear ring 511, it will be gradually dissipated by each stage of the transmission pair, making it difficult to break through the braking constraint of the locking disc 91, and even more difficult to transmit in the reverse direction to the steering motor 7 along the steering reduction chain 8, thus avoiding accidental rotation of the steering motor 7. Even in extreme slippage conditions, the composite locking path formed by the locking disc 91 and the multi-stage transmission pair can still keep the transmission gear ring 511 stationary, ensuring synchronous output of the output half-shafts 6 on both sides, providing stable traction for the vehicle. After the vehicle leaves the extreme working condition, the controller releases the braking force of the locking unit 92, the locking disc 91 resumes free rotation, the steering reduction chain 8 reconnects to the steering power, and the vehicle resumes normal steering function.

[0040] By using the aforementioned locking actuator 9, power is prevented from being diverted to the steering mechanism, thus preventing the limited traction force from being decomposed into longitudinal and lateral components, further reducing the effective traction force, and even potentially causing deeper digging and deterioration of the vehicle's posture due to lateral slippage. Under extreme conditions, the locking actuator 9 forcibly locks the output half-shafts 6 on both sides, while simultaneously locking the steering reduction chain 8, concentrating all power on longitudinal traction, avoiding the loss of adhesion caused by steering, and maximizing the ability to get out of trouble.

[0041] Furthermore, the locking action can be performed during the transmission of walking power without interrupting the output of walking power. It can lock the vehicle immediately when slipping, getting stuck, or other dangerous situations occur, preventing the situation from worsening.

[0042] like Figure 3 As shown, in some embodiments, the main reduction pair 3 includes a driving bevel gear 31 and a driven bevel gear 32 that mesh with each other. The driving bevel gear 31 is coaxially fixedly installed on the output end of the power input shaft 21. The axis of the driven bevel gear 32 is perpendicular to the axis of the power input shaft 21. The output end of the driven bevel gear 32 is coaxially connected to the bridge main shaft 4, thereby realizing the reversal and deceleration of power. The walking power input along the axial direction of the power input shaft 21 is diverted and transmitted to both sides of the axial direction. The bridge main shaft 4 and the wheel-side reduction module 5 are coaxially arranged.

[0043] like Figure 2 and Figure 6 As shown, the wheel-side reduction module 5 further includes a two-stage planetary reduction mechanism 52. The planet carrier of the first-stage planetary reduction mechanism 51 is connected to the sun gear of the second-stage planetary reduction mechanism 52. The planet carrier of the second-stage planetary reduction mechanism 52 is connected to the output half-shaft 6. The two-stage planetary reduction can obtain a larger reduction ratio to meet the high torque output requirements of agricultural vehicles.

[0044] The first-stage planetary reduction mechanism 51 and the second-stage planetary reduction mechanism 52 respectively construct the planetary transmission system. Both include planetary gears, planet carriers, and sun gears. To further distinguish between the first-stage planetary reduction mechanism 51 and the second-stage planetary reduction mechanism 52: The first-stage planetary reduction mechanism 51 includes a first-stage sun gear, multiple first-stage planet gears, a first-stage planet carrier, and a first-stage ring gear. The first-stage planet gears are rotatably mounted on the first-stage planet carrier. The first-stage ring gear is the aforementioned transmission ring gear 511. The first-stage sun gear is connected to the end of the bridge main shaft 4. The first-stage planet gears mesh between the first-stage ring gear and the first-stage sun gear. The secondary planetary reduction mechanism 52 includes a secondary sun gear, multiple secondary planet gears, a secondary planet carrier, and a secondary ring gear. The secondary planet gears are rotatably mounted on the secondary planet carrier. The primary planet carrier has a drive shaft end, which is connected to the secondary sun gear. The secondary planet gears mesh between the secondary sun gear and the secondary ring gear. The secondary planet carrier is connected to one end of the output half-shaft 6, and the other end of the output half-shaft 6 extends out of the main housing 10.

[0045] The installation structure of the first-stage planetary reduction mechanism 51 and the second-stage planetary reduction mechanism 52 within the main housing 10 is a conventional technical method in the mechanical field, and will not be described in detail here.

[0046] Further reference Figure 4 and Figure 5 As shown, in some embodiments, the steering reduction chain 8 includes a steering output shaft 81, a steering transmission shaft 82, a rotation conversion transmission pair 83, and two side transmission shafts 84. The steering output shaft 81 is disposed on the actuating end of the steering motor 7. Multiple steering transmission units are driven between the steering output shaft 81 and the steering transmission shaft 82, that is, both the steering output shaft 81 and the steering transmission shaft 82 are provided with a steering transmission unit. The steering transmission units between the steering output shaft 81 and the steering transmission shaft 82 can be directly engaged, or multiple steering transmission units can be connected between the two. The input end of the rotation direction conversion transmission pair 83 is connected to the steering transmission shaft 82, and the two output ends of the rotation direction conversion transmission pair 83 are respectively connected to the two side transmission shafts 84. The rotation directions of the output ends of the rotation direction conversion transmission pair 83 are opposite. The reversing gear 85 is set on the side transmission shaft 84. By setting the rotation direction conversion transmission pair 83, the steering power from the steering motor 7 is received, and the unidirectional rotation of the steering transmission shaft 82 is converted into the opposite rotation of the two side transmission shafts 84, thereby driving the transmission gear rings 511 on both sides to rotate in opposite directions, realizing differential steering and stationary steering.

[0047] Furthermore, the reversing gear 85 is a cylindrical gear, and the external gear ring 512 of the transmission gear ring 511 is the external tooth that meshes with the cylindrical gear. The meshing method between the cylindrical gear and the external gear ring 512 is simple in structure, reliable in transmission, and easy to process and maintain.

[0048] Specifically, the rotational reversing transmission pair 83 is configured to receive steering power and has two output ends that rotate in opposite directions.

[0049] Further reference Figure 5 In some embodiments, the rotational reversing transmission pair 83 includes a first bevel gear 831 disposed at the upper end of the steering transmission shaft 82 and a second bevel gear 832 disposed on the side transmission shaft 84. The second bevel gear 832 is spaced apart from the transmission gear ring 511, and both second bevel gears 832 mesh with the first bevel gear 831. The two second bevel gears 832 are coaxial and symmetrically arranged about the axis of the first bevel gear 831, located on both sides of the axis of the first bevel gear 831, and meshing in opposite directions. After the power is diverted by the first bevel gear 831, the two side transmission shafts 84 obtain rotational motion in opposite directions under the meshing drive of the two second bevel gears 832, thereby driving the reversing gear 85 to drive the transmission gear rings 511 on both sides to rotate in opposite directions, thereby realizing differential steering.

[0050] In some embodiments, as a further implementation of the steering transmission unit, the steering transmission unit includes a steering drive wheel 86 disposed on the steering output shaft 81 and a steering driven wheel 87 disposed on the steering transmission shaft 82. At least one steering reduction wheel 88 meshes between the steering drive wheel 86 and the steering driven wheel 87. The steering drive wheel 86, the steering driven wheel 87 and the steering reduction wheel 88 are all cylindrical gears, which allows the steering transmission unit between the steering transmission shaft 82 and the steering output shaft 81 in the steering reduction chain 8 to be arranged in a flat manner. It does not require additional installation space to be reserved for cross-shaft transmission, effectively compressing the overall space occupied by the steering transmission module, ensuring the overall flat layout of the power unit, and adapting to the limited installation space at the bottom of the chassis.

[0051] Thus, the aforementioned driven steering wheel 87, driving steering wheel 86, steering reduction wheel 88, as well as the first bevel gear 831 and the second bevel gear 832 constitute a steering transmission unit, forming a multi-stage reduction transmission path. This allows the power output from the steering motor 7 to be transmitted to the steering transmission shaft 82 via a multi-stage gear pair, and then diverted by the rotational reversing transmission pair 83 to the two side transmission shafts 84, ultimately driving the reversing gear 85 to rotate the two side transmission gear rings 511 in the opposite direction.

[0052] The braking torque provided by the locking unit 92 at the locking disc 91 is amplified step by step by the reduction ratios when reflected to the transmission gear ring 511. Therefore, the locking unit 92 only needs to provide a relatively small braking force at the front end of the steering output shaft 81 to obtain an amplified locking torque at the transmission gear ring 511, so that the transmission gear ring 511 can reliably stop rotating.

[0053] In this embodiment, the number and number of teeth of the steering reduction wheel 88 can be flexibly adjusted according to the overall layout space and steering ratio requirements, so that the power unit can be adapted to different models of electric rotary tillers and improve versatility. In this embodiment, in order to save space at the bottom of the agricultural vehicle, the number of steering reduction wheels 88 is one. By setting the steering reduction wheel 88, multi-stage reduction can be achieved between the steering output shaft 81 and the steering transmission shaft 82, while increasing the number of meshing points and improving the stability of the locking disc 91 in the locked state.

[0054] Further reference Figure 5 As one implementation of the locking disc 91 arrangement, the locking disc 91 is coaxially disposed at the bottom of the steering output shaft 81 or the steering transmission shaft 82. When locked, it locks the entire steering reduction chain 8, achieving synchronous locking of the steering mechanism. Through this improvement, the locking actuator 9 is integrated into the lower space of the input end of the steering reduction chain 8, eliminating the need for additional space on the side or top of the transmission system. It can form an axially stacked layout with the steering motor 7 or the steering reduction chain 8, reducing the lateral dimension of the steering transmission module and adapting to the requirement of a flat bottom. Simultaneously, the locking disc 91 is positioned close to the steering power input end, cutting off the braking force transmission path at the source during locking, preventing external forces from impacting the core components of the steering motor 7. Furthermore, the bottom mounting position facilitates the disassembly and maintenance of the locking unit 92, reducing the difficulty of later maintenance operations.

[0055] In a preferred embodiment, the steering output shaft 81 has an axial extension portion disposed away from the steering motor 7, and the locking disc 91 is coaxially disposed on the axial extension portion.

[0056] In this embodiment, when locking is required, the locking unit 92 applies braking force to the locking disc 91. This braking force is then transmitted to the reversing gear 85 at the end of the steering reduction chain 8 through the meshing transmission relationship of each steering transmission unit, forcing the transmission gear rings 511 on both sides to stop rotating simultaneously. Because multiple transmission units share the braking force, the locking force is distributed along the steering reduction chain 8, no longer limited to a single meshing point. This avoids the problem of insufficient locking capability caused by localized locking, improving the reliability of the locking. Simultaneously, the locking disc 91 acts directly on the follower component at the actuating end of the steering motor 7. Even with significant fluctuations in external torque, the braking force is applied at the input end, effectively preventing reverse drive on the steering motor 7 side and preventing malfunctions caused by accidental rotation of the steering input shaft. This ensures that the output half-shafts 6 on both sides remain rigidly synchronized under extreme conditions, thereby improving the stability and safety of the vehicle.

[0057] Optionally, the locking unit 92 is a caliper-type locking mechanism. When locking is required, the controller outputs a control signal to drive the caliper to grip the locking disc 91, relying on friction to achieve locking and prevent rotation. When unlocking is required, the caliper releases, and the locking disc 91 resumes free rotation. This structure has a fast response, sufficient locking force, and a simple and reliable control method, making it compatible with the overall vehicle electronic control system of electric rotary tillers.

[0058] The locking unit 92 mentioned above can be either electrically driven or hydraulically driven.

[0059] In other embodiments, the execution end of the locking unit 92 may also be provided with a geometric interference structure, such as a concave-convex structure, between it and the locking disk 91 to improve the stability in the locked state.

[0060] In some other embodiments, the locking unit 92 may also be a wet multi-plate clutch locking structure, which is a conventional technical means in the mechanical field and will not be described in detail here.

[0061] In some embodiments, the spatial arrangement of the walking power module relative to the wheel-side reduction module 5 is as follows: Two side drive shafts 84 are coaxial and opposite to each other, and are arranged parallel to each other below the axis of the output half shaft 6. The second bevel gear 832 at one end of the two side drive shafts 84 is close to the axial side of the power input shaft 21. Preferably, the axial direction of the steering drive shaft 82 is aligned with the axis of the power input shaft 21. The reversing gear 85 on the other end of the two side drive shafts 84, in mesh with the transmission gear ring 511, preferably has its axial dimension aligned with the axial dimension of the transmission gear ring 511. Therefore, the lower side drive shaft 84, steering drive shaft 82, first bevel gear 831 and second bevel gear 832, and steering transmission unit on steering drive shaft 82 can all share the lateral space with wheel-side reduction module 5. The steering drive shaft 82 is arranged parallel to the steering output shaft 81 and extends vertically to the lower part of the axis of the output half shaft 6. The steering motor 7 is coaxial with the steering output shaft 81 and extends toward the axis of the output half shaft 6. Multiple steering drive units are arranged in the same plane to achieve a compact spatial layout of the steering drive module, making the steering drive module as a whole flat, which helps to reduce the height of the power unit and adapt to the installation space at the bottom of the chassis.

[0062] The walking power module and the upper power distribution module form a layered layout, which avoids spatial interference between the steering reduction chain 8 and the walking power chain, and can greatly reduce the longitudinal height of the power unit, ensuring that the bottom is flat.

[0063] Combination Figure 1 In some embodiments, the spatial arrangement of the steering transmission module relative to the wheel-side reduction module 5 is as follows: The power input shaft 21 extends vertically to the middle of the axis of the output half shafts 6 on both sides and is set away from the steering transmission module. The continuously variable transmission mechanism 2 extends in the same direction as the steering reduction chain 8. The axes of the travel motor 1 and the steering motor 7 are parallel and arranged opposite to each other. That is to say, the travel motor 1 and the steering motor 7 extend in their respective relative directions, thereby reducing the space occupied in the height direction. The travel power path and the steering power path are independent of each other and do not interfere with each other. At the same time, the center of gravity of the whole machine is in the middle, which is conducive to the stability of vehicle driving.

[0064] from Figure 1 As can be seen, the travel motor 1 and the steering motor 7 are misaligned in the lateral direction. This is due to the number and size ratio of the transmission units inside the steering transmission unit and the continuously variable transmission mechanism 2. In some preferred embodiments, the travel motor 1 and the steering motor 7 can be arranged coaxially to further reduce the lateral dimension.

[0065] In the above embodiments, the walking power module and the steering transmission module are arranged in the same direction in the lateral space.

[0066] It is worth mentioning that the system also includes a main housing 10, with the wheel-side reduction module 5 housed within the main housing 10, and the end of the output half-shaft 6 extending out of the main housing 10. The steering transmission module has a steering transmission housing 11, with the steering motor 7 located outside the steering transmission housing 11. The steering output shaft 81 and the steering transmission shaft 82, as well as the steering transmission unit between them, are all located within the steering transmission housing 11. The continuously variable transmission mechanism 2 has a gearbox housing 12, with the transmission units inside the continuously variable transmission mechanism 2 all located within the gearbox housing 12. The travel motor 1 is located outside the gearbox housing 12. The steering transmission housing 11 and the gearbox housing 12 are located on the upper and lower sides of the wheel-side reduction module 5, and provide flat boundaries on the upper and lower sides. The bottom of the power unit is flat, which facilitates the vehicle chassis layout and improves the vehicle's passability.

[0067] Furthermore, the steering transmission housing 11 and the gearbox housing 12 are connected on the upper and lower sides of the main housing 10, allowing the entire power unit's walking power module, power distribution module, wheel-side reduction module 5, and steering transmission module to be integrated and installed into a complete and independent power pack. This pack can be directly hoisted and fixed to the preset mounting position at the bottom of the electric rotary tiller chassis, making it compatible with different chassis specifications and highly versatile. During final assembly, only the power output connection and electronic control interface connection need to be completed. When the power unit malfunctions, it can be directly replaced as a whole, reducing downtime for agricultural machinery and lowering usage and maintenance costs.

[0068] The present invention also provides a control method for the power unit of an electric rotary tiller, applied to the aforementioned power unit of the electric rotary tiller, comprising the following steps: Obtain vehicle operating status information, including the speed of the travel motor 1, the speed of the steering motor 7, and the speed difference or torque difference of the output half-shafts 6 on both sides; Based on the operating status information, determine the current operating mode of the vehicle. The operating modes include straight driving mode, differential steering mode, stationary steering mode and forced lock mode. The conditions for determining that the vehicle is in forced lock mode include: the speed difference between the two output half shafts 6 exceeds a preset threshold and the duration exceeds a preset time, or the torque of one output half shaft 6 is lower than a preset threshold and the torque of the other output half shaft 6 is higher than a preset threshold.

[0069] When the vehicle is determined to be in forced locking mode, the locking execution component 9 is activated, causing the locking unit 92 to apply braking force to the locking disc 91. The locking disc 91 stops rotating, and through the linkage of the steering reduction chain 8, the reversing gear 85 stops rotating, thereby stopping the transmission gear ring 511. The output half shafts 6 on both sides output the same speed and torque. At the same time, the steering motor 7 is forced to stop due to the locking of the steering reduction chain 8. After the locking unit 92 is activated, it confirms that the steering motor 7 has stopped by detecting the back electromotive force or current change of the steering motor 7 and sends a locking success signal.

[0070] When the vehicle is determined to be in differential steering mode, the speed ratio between the steering motor 7 and the travel motor 1 is controlled according to the preset turning arc parameters, so that the transmission gear rings 511 on both sides generate a speed difference that matches the turning arc.

[0071] The specific working method of the present invention will be described below in conjunction with five typical working conditions.

[0072] Operating Condition 1: Straight-line driving. The travel motor 1 is started, while the steering motor 7 is not. Power is distributed evenly to the output half-shafts 6 on both sides via the transmission mechanism, power input shaft 21, main reduction pair 3, bridge main shaft 4, and the first-stage and second-stage planetary reduction mechanisms 51 and 52 on both sides. At this time, the reversing gear 85 does not rotate, the outer gear ring 512 of the transmission gear ring 511 is stationary, and the output half-shafts 6 on both sides output the same speed and torque.

[0073] Operating Condition 2: Differential Steering. The travel motor 1 and steering motor 7 start simultaneously. The travel motor 1 provides travel power, and the steering motor 7 provides steering power. The steering power is transmitted via the steering output shaft 81, steering transmission unit, steering transmission shaft 82, first bevel gear 831, second bevel gear 832, side transmission shaft 84, and reversing gear 85 to the outer gear rings 512 of the two side transmission gear rings 511. Since the two side transmission shafts 84 are coaxial and oppositely positioned, the reversing gear 85 causes the outer gear rings 512 of the two side transmission gear rings 511 to rotate in opposite directions, while the travel power causes the inner gear rings of the two side transmission gear rings 511 to rotate in the same direction, thus forming differential steering. By adjusting the speed ratio of the steering motor 7 and the travel motor 1, the turning arc can be controlled, allowing the wheels or tracks to turn close to the edge. For example, based on the curvature of the curve boundary, the output ratio of the steering motor 7 and the output ratio of the travel motor 1 can be adjusted according to a preset ratio to achieve a specific turning arc.

[0074] Operating Condition 3: Turning in place. Only the steering motor 7 is started, and the travel motor 1 is not started. The steering power is transmitted to the outer gear ring 512 of the two transmission gear rings 511 via the steering reduction chain 8, causing the two transmission gear rings 511 to turn in opposite directions, while the inner gear ring remains stationary due to the lack of travel power input. The output power has the same speed but opposite direction, thus forming a turning in place.

[0075] Condition 4: Forced locking under extreme conditions. When the vehicle is unable to escape the obstacle, the locking unit 92 activates and brakes the locking disc 91. The steering output shaft 81, steering transmission unit, steering transmission shaft 82, first bevel gear 831, side transmission shaft 84, reversing gear 85, and transmission ring gear 511 all stop rotating, while the output half-shafts 6 on both sides rotate synchronously. At this time, the entire steering reduction chain 8 is locked, and the steering motor 7 stops rotating, achieving synchronous locking of the steering mechanism during locking. The output half-shafts 6 on both sides output at the same speed and torque. Under this condition, the vehicle maintains straight-line travel, with all power concentrated on longitudinal traction, avoiding the loss of adhesion and deepening of ruts caused by steering, thus maximizing the ability to escape from obstacles.

[0076] The above embodiments can be combined or substituted with each other. Without departing from the concept of the present invention, the technical features in each embodiment can be flexibly combined according to the actual application scenario.

[0077] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A power unit for an electric rotary tiller, installed at the bottom of the chassis of an agricultural vehicle, characterized in that, include: The walking power module includes a walking motor (1) for providing walking power, and a continuously variable transmission mechanism (2) provided on the output end of the walking motor (1), wherein the output end of the continuously variable transmission mechanism (2) is provided with a power input shaft (21). The power distribution module includes a main reduction gear (3) that is driven to the power input shaft (21), and a bridge main shaft (4) that is driven to the main reduction gear (3); Wheel-side reduction modules (5) are connected to both ends of the bridge main shaft (4); each wheel-side reduction module (5) includes at least one-stage planetary reduction mechanism (51), the actuating end of the first-stage planetary reduction mechanism (51) is connected to an output half shaft (6); the first-stage planetary reduction mechanism (51) has a transmission gear ring (511), the transmission gear ring (511) includes an inner gear ring for constructing a planetary transmission system, and an outer gear ring (512) disposed on the outer periphery of the transmission gear ring (511); The steering transmission module includes a steering motor (7) that provides steering power and a steering reduction chain (8) that receives steering power. The steering reduction chain (8) includes a plurality of meshing steering transmission units. Each steering transmission unit includes two reversing gears (85) located at the end of the steering reduction chain (8). The two reversing gears (85) rotate in opposite directions. The reversing gears (85) mesh with the outer gear ring (512) of the transmission gear ring (511) so that the two sides of the transmission gear ring (511) rotate in opposite directions. The locking actuator (9) includes a locking disc (91) and a locking unit (92) for applying braking force to the locking disc (91). The locking disc (91) is located on a component in the steering reduction chain (8) that can rotate synchronously with the actuating end of the steering motor (7). The locking unit (92) holds the locking disc (91) by the braking force, thereby forcing the transmission gear ring (511) to stop rotating, so that the output half shafts (6) on both sides are rigidly connected.

2. The power unit of an electric rotary tiller according to claim 1, characterized in that: The steering reduction chain (8) includes a steering output shaft (81), a steering transmission shaft (82), a rotation conversion transmission pair (83), and two side transmission shafts (84). Multiple steering transmission units are driven between the steering output shaft (81) and the steering transmission shaft (82). The steering output shaft (81) is located on the operating end of the steering motor (7). The input end of the rotation direction conversion transmission pair (83) is connected to the steering transmission shaft (82), and the two output ends of the rotation direction conversion transmission pair (83) are respectively connected to the two side transmission shafts (84), and the rotation directions of the output ends of the rotation direction conversion transmission pair (83) are opposite. The reversing gear (85) is provided on the side transmission shaft (84).

3. The power unit of an electric rotary tiller according to claim 2, characterized in that: The steering transmission unit includes a steering drive wheel (86) on the steering output shaft (81) and a steering driven wheel (87) on the steering transmission shaft (82). At least one steering reduction wheel (88) meshes between the steering drive wheel (86) and the steering driven wheel (87).

4. The power unit of an electric rotary tiller according to claim 3, characterized in that: The rotation direction conversion transmission pair (83) includes a first bevel gear (831) disposed at the end of the steering transmission shaft (82) and a second bevel gear (832) disposed on the side transmission shaft (84). The two second bevel gears (832) are symmetrically disposed on both sides of the axis of the first bevel gear (831) and rotate in opposite directions.

5. The power unit of an electric rotary tiller according to claim 1, characterized in that: The locking disc (91) is coaxially disposed at the bottom of the steering output shaft (81) or the steering transmission shaft (82).

6. The power unit of an electric rotary tiller according to claim 1, characterized in that: The wheel-side reduction module (5) also includes a secondary planetary reduction mechanism (52). The planet carrier of the primary planetary reduction mechanism (51) is connected to the sun gear of the secondary planetary reduction mechanism (52) via a transmission. The planet carrier of the secondary planetary reduction mechanism (52) is connected to the output half shaft (6).

7. The power unit of an electric rotary tiller according to claim 1, characterized in that: The continuously variable transmission (2) is equipped with a gear shifting mechanism (22) and a braking mechanism (23).

8. The power unit of an electric rotary tiller according to claim 2, characterized in that: The two side drive shafts (84) are coaxial and opposite to each other, and are arranged parallel to the lower part of the axis of the output half shaft (6). The steering drive shaft (82) is arranged parallel to the steering output shaft (81) and extends vertically to the lower part of the axis of the output half shaft (6). The steering motor (7) is coaxial with the steering output shaft (81) and extends toward the axis of the output half shaft (6). The multiple steering drive units are arranged in a coplanar manner.

9. The power unit of an electric rotary tiller according to claim 8, characterized in that: The power input shaft (21) extends vertically to the middle of the axis of the output half shafts (6) on both sides and is set away from the steering transmission module. The continuously variable transmission mechanism (2) extends in the same direction as the steering reduction chain (8), and the walking motor (1) and the steering motor (7) are arranged parallel to each other and opposite to each other.

10. A control method for the power unit of an electric rotary tiller, applied to the power unit of the electric rotary tiller according to any one of claims 1 to 9, characterized in that, Includes the following steps: Obtain vehicle operating status information, which includes the speed of the walking motor (1), the speed of the steering motor (7), and the speed difference or torque difference of the output half shafts (6) on both sides; Based on the operating status information, the current operating mode of the vehicle is determined. The operating mode includes straight driving mode, differential steering mode, stationary steering mode and forced locking mode. When the vehicle is determined to be in the forced locking mode, the locking execution component (9) is activated, so that the locking unit (92) applies braking force to the locking disc (91). The locking disc (91) stops rotating and, through the linkage of the steering reduction chain (8), the reversing gear (85) stops rotating, thereby stopping the transmission gear ring (511). The output half shafts (6) on both sides output the same speed and torque. At the same time, the steering motor (7) is forced to stop due to the locking of the steering reduction chain (8).

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