CN112455530B

CN112455530B - Angle transmission device, steering system and vehicle

Info

Publication number: CN112455530B
Application number: CN201910843426.6A
Authority: CN
Inventors: 陈晓波; 刘明; 丁广福; 王永令; 秦宬
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2022-06-10
Anticipated expiration: 2039-09-06
Also published as: CN112455530A

Abstract

The invention belongs to the technical field of vehicle steering, and particularly relates to an angle transmission device, a steering system and a vehicle, wherein the angle transmission device comprises a shell, a motor, a speed reducing mechanism, a first shaft, a second shaft, a third shaft, a torsion bar, a first bevel gear, a second bevel gear and a torque angle sensor, wherein the first shaft, the second shaft and the third shaft are rotatably supported in the shell; the speed reduction mechanism is connected between the motor and the third shaft. The angle transmission device can save a mechanism which has a complex structure and many parts and is used for selectively disconnecting and connecting, and reduce the complexity and the production cost of the structure of the angle transmission device.

Description

Angle transmission device, steering system and vehicle

Technical Field

The invention belongs to the technical field of vehicle steering, and particularly relates to an angle transmission device, a steering system and a vehicle.

Background

An existing angle transmission device of a steering system comprises a body, an input shaft assembly, an output shaft assembly and a power-assisted assembly are installed in the body, the input shaft assembly comprises a first installation support installed in the body, a torsion bar is installed in the first installation support, the torsion bar is sleeved with an input shaft, an output end of the input shaft is sleeved with a driving bevel gear, a steering sensor is connected with the torsion bar, the output shaft assembly comprises a second installation support installed in the body, an output shaft is installed on the second installation support, a driven bevel gear meshed with the driving bevel gear is installed on the output shaft, the power-assisted assembly comprises a power-assisted motor, a driving straight gear is installed on an output shaft of the power-assisted motor, and a driven straight gear meshed with the driving straight gear is further installed on the output shaft. The angle transmission device can realize the rotation assistance, automatic rotation and active alignment of the steering wheel by controlling the power-assisted motor.

The above-described angle drive has the following problems:

(1) in order to obtain torque detection, the input shaft and the drive bevel gear are necessarily required to be disconnected and form a relative rotation quantity, which is represented by the deformation quantity of the torsion bar fixed at the upper end and the lower end of the input shaft, so that a mechanism capable of being selectively disconnected and combined is required between the input shaft and the drive bevel gear, and the angle transmission device is complex in structure and high in cost.

(2) No limit structure is arranged between the two parts connected with the torsion bar, so that the torsion bar can be continuously deformed, and the torsion bar can be permanently deformed to cause failure of the torsion bar.

(3) Its reduction gears arranges the extension section at the output shaft, and the centre of output shaft does not set up bearing structure, and output shaft rotational stability is relatively poor, and life reduces. The speed reducing mechanism adopting the double straight gears has the problem that the size and the weight of the speed reducing mechanism are overlarge on the premise of ensuring that the speed ratio is proper and considering the structural strength of the double straight gears.

(4) The power-assisted motor adopts a permanent magnet brush direct current motor, oscillation and step-out are easy to generate when load suddenly changes, and the permanent magnet brush direct current motor has short service life and poor energy-saving property.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: aiming at the problem that the structure of the conventional angle transmission device is complicated because a mechanism capable of being selectively disconnected and combined is required between an input shaft and a driving bevel gear, the angle transmission device, a steering system and a vehicle are provided.

In order to solve the above technical problem, in one aspect, an embodiment of the present invention provides an angular transmission device, including a housing, a motor, a speed reduction mechanism, a first shaft, a second shaft, a third shaft, a torsion bar, a first bevel gear, a second bevel gear, and a torque angle sensor for detecting torque and a rotation angle of the first shaft, where the speed reduction mechanism, the first shaft, the second shaft, the third shaft, the torsion bar, the first bevel gear, and the second bevel gear are disposed in the housing, the first shaft, the second shaft, and the third shaft are rotatably supported in the housing, a first end of the first shaft penetrates through the housing, the torsion bar is fixed between a second end of the first shaft and a first end of the third shaft, the first shaft, the torsion bar, and the third shaft are coaxially disposed, the first bevel gear is fixed at a second end of the third shaft, and a first end of the second shaft penetrates through the housing, the second bevel gear is fixed at the second end of the second shaft;

one of the first shaft and the second shaft is an input shaft, and the other shaft is an output shaft;

the speed reducing mechanism is connected between the motor and the third shaft, and the motor drives the third shaft to rotate through the speed reducing mechanism.

Optionally, the first end of the torsion bar is connected to the first shaft by a spline or a latch, and the second end of the torsion bar is connected to the third shaft by a spline or a latch.

Optionally, a first spline hole is formed in the first shaft, and a first external spline inserted into the first spline hole is formed at the first end of the torsion bar;

and a second spline hole is formed in the third shaft, and a second external spline which is inserted in the second spline hole is arranged at the second end of the torsion bar.

Optionally, a portion of the torsion bar located between the first external spline and the second external spline forms a reduced diameter section, an outer diameter of the reduced diameter section is smaller than outer diameters of the first external spline and the second external spline, and an annular gap is formed between an outer periphery of the reduced diameter section and an inner wall of the first splined hole to provide a deformation space of the torsion bar.

Optionally, a third external spline and a bolt limiting ring groove are arranged at the first end of the input shaft, and the input shaft is connected with a universal joint assembly at the lower end of the steering column through the third external spline and the bolt limiting ring groove.

Optionally, a key groove is formed at the first end of the third shaft, a key block inserted into the key groove is arranged at the second end of the first shaft, and a first stop position and a second stop position which are not overlapped are formed on the inner wall of the key groove;

When the torsion bar deforms to cause relative movement of the first shaft and the third shaft, the key block can rotate in the key groove within an angle range limited by the first stop position and the second stop position, and when the key block is in contact with the key groove at the first stop position or the second stop position, the first shaft and the third shaft are integrated and directly transmit steering torque to prevent further deformation of the torsion bar;

in the manual steering mode, when the key block is in contact with the key groove at the first stop or the second stop, the rotational resistance of the steering wheel is increased to indicate that the extreme position of steering is reached.

Optionally, the key block is a square block, and the cross section of the key groove is oblong or elliptical.

Optionally, the speed reducing mechanism includes a worm fixed or integrally formed on an output shaft of the motor and a worm wheel fixed or integrally formed on the third shaft, an outer casing of the motor is fixed to an outside of the housing, the output shaft of the motor penetrates into the housing, and the worm is engaged with the worm wheel.

Optionally, the housing includes a bottom shell and an end cover fixed on the bottom shell;

the first shaft is rotatably supported on the end cover through a first bearing;

The second shaft is rotatably supported on the bottom shell through a second bearing, and the second bearing is abutted with one side end face of the second bevel gear;

the third shaft is rotatably supported on the bottom shell through a third bearing and a fourth bearing, the third bearing is located on one axial side of the worm wheel, and the fourth bearing is abutted to one side end face of the first bevel gear.

Optionally, the torque angle sensor includes a magnetic ring, a magnetic ring housing, and a magnetic resistance, the magnetic ring is fixed on an outer circumference of the first shaft and rotates along with the first shaft, the magnetic ring housing is fixed on the housing, and the magnetic resistance is disposed around the magnetic ring and fixed in the magnetic ring housing.

According to the angle drive device of the embodiment of the present invention, the disconnected first shaft and third shaft are connected by the torsion bar, the first bevel gear is provided on the third shaft and engaged with the second bevel gear of the second shaft, and the torque and the rotation angle of the first shaft are detected by the torque angle sensor. Thus, the first bevel gear need not be selectively disengaged and engaged with the first shaft when detecting torque. The mechanism which has a complex structure and many parts and is used for selectively disconnecting and connecting can be saved, and the complexity and the production cost of the structure of the angle transmission device are reduced. The angle transmission device is suitable for electric steering power assistance and also suitable for automatic steering (electric steering) so as to realize the unmanned function.

In another aspect, an embodiment of the present invention further provides a steering system, which includes the above-mentioned angle transmission device.

In still another aspect, embodiments of the present invention further provide a vehicle including the angular transmission device described above.

Drawings

FIG. 1 is a cross-sectional view of an angle drive provided by one embodiment of the present invention;

FIG. 2 is an exploded view of the first shaft, third shaft and torsion bar of the angular gear apparatus according to one embodiment of the present invention;

FIG. 3 is an enlarged view of a key block and keyway of an angle drive according to one embodiment of the present invention;

fig. 4 is an assembly view of a torque angle sensor and a first shaft of an angle drive according to an embodiment of the present invention.

The reference numerals in the specification are as follows:

1. a housing; 2. a motor; 3. a speed reduction mechanism; 31. a worm; 32. a worm gear; 4. a first shaft; 41. a first splined bore; 42. an annular gap; 43. a key block; 5. a second shaft; 6. a third axis; 61. a second spline hole; 62. a keyway; 7. a torsion bar; 71. a first external spline; 72. a second male spline; 73. a reducing section; 8. A first bevel gear; 9. a second bevel gear; 10. a torque rotation angle sensor; 101. a magnetic ring; 102. a magnetic ring is sleeved; 103. magnetic resistance; 20. A first bearing; 30. a second bearing; 40. a third bearing; 50. and a fourth bearing.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

As shown in fig. 1 to 4, an angle transmission device according to an embodiment of the present invention includes a housing 1, a motor 2, a speed reduction mechanism 3, a first shaft 4, a second shaft 5, a third shaft 6, a torsion bar 7, a first bevel gear 8, a second bevel gear 9, and a torque angle sensor 10 for detecting torque and a rotation angle of the first shaft 4, wherein the speed reduction mechanism 3, the first shaft 4, the second shaft 5, the third shaft 6, the torsion bar 7, the first bevel gear 8, and the second bevel gear 9 are disposed in the housing 1, the first shaft 4, the second shaft 5, and the third shaft 6 are rotatably supported in the housing 1, a first end of the first shaft 4 penetrates through the housing 1, the torsion bar 7 is fixed between a second end of the first shaft 4 and a first end of the third shaft 6, the first shaft 4, the torsion bar 7, and the third shaft 6 are coaxially disposed, the first bevel gear 8 is fixed at a second end of the third shaft 6, the first end of the second shaft 5 penetrates out of the shell 1, and the second bevel gear 9 is fixed at the second end of the second shaft 5. The speed reducing mechanism 3 is connected between the motor 2 and the third shaft 6, and the motor 4 drives the third shaft 6 to rotate through the speed reducing mechanism 3.

In one embodiment, the first shaft 4 is perpendicular to the second shaft 5, the first bevel gear 8 and the second bevel gear 9 are meshed orthogonally, and the electric power-assisted angle transmission device is an angle transmission with an input shaft and an output shaft intersecting angle of 90 degrees.

However, the electrically assisted angle drive may also be applied to angle drives of other angles, for example 120 degrees or 135 degrees, etc. At this time, the meshing angle of the first bevel gear 8 and the second bevel gear 9 is 120 degrees or 135 degrees.

The torque angle sensor 10 employs the TAS series.

As shown in fig. 4, the torque angle sensor 10 includes a magnetic ring 101, a magnetic ring housing 102, and a ring-shaped magnetic resistance 103, the magnetic ring 101 is fixed on the outer circumference of the first shaft 4 and rotates with the first shaft 4, the magnetic ring housing 102 is fixed on the housing 1, and the magnetic resistance 103 is disposed around the magnetic ring 101 and fixed in the magnetic ring housing 102.

The motor 2 is a brushless dc motor, for example, a 24V brushless dc motor. Compared with the traditional permanent magnet brush direct current motor, the permanent magnet brush direct current motor has longer service life and better energy saving property.

Of course, other operating voltages or other controllable motor types (e.g., permanent magnet synchronous motors) may perform the same function.

In one embodiment, as shown in fig. 1, the first shaft 4 is an input shaft and the second shaft 5 is an output shaft. The first end of the first shaft 4 (input shaft) is provided with a third external spline and a bolt limiting ring groove, and the first shaft 4 (input shaft) is connected with a universal joint assembly at the lower end of the steering column through the third external spline and the bolt limiting ring groove. The upper end of the steering column is connected with a steering wheel.

The torque angle sensor 10 detects the relative rotation angle range of the first shaft 4 and the torsion bar 2, converts the relative rotation angle range into a torque range according to the rigidity of the torsion bar 7, and when the electric control steering mode is switched into the manual steering mode, the first shaft 4 and the third shaft 6 rotate relatively, so that the torque input of the motor 2 can be judged when to be cut off according to the torque and the manual steering mode can take over the torque. The torque angle sensor 10 detects the rotation angle of the first shaft 4 at the same time, the rotation angle of the input shaft 1 corresponds to the angle position of the steering wheel, and the electric power-assisted angle transmission device after zero calibration can transmit the real-time rotation angle of the input shaft to a controller with a storage function, so that the controller can always determine the current angle position of the steering wheel.

A first end of the torsion bar 7 is connected with the first shaft 4 through a spline or a plug pin, and a second end of the torsion bar 7 is connected with the third shaft 6 through a spline or a plug pin.

In one embodiment, as shown in fig. 1 and 2, a first splined hole 41 is formed in the first shaft 4, and a first end of the torsion bar 7 is provided with a first external spline 71 inserted into the first splined hole 41. A second spline hole 61 is arranged in the third shaft 6, and a second external spline 72 inserted in the second spline hole 61 is arranged at the second end of the torsion bar 7.

In one embodiment, as shown in fig. 1 and fig. 2, a portion of the torsion bar 7 located at the first external spline 71 and the second external spline 72 forms a reduced diameter section 73, an outer diameter of the reduced diameter section 73 is smaller than outer diameters of the first external spline 71 and the second external spline 72, and an annular gap 42 is formed between an outer periphery of the reduced diameter section 73 and an inner wall of the first splined hole 41 to provide a deformation space of the torsion bar 7.

In an embodiment, as shown in fig. 3, a first end of the third shaft 6 is provided with a key slot 62, a second end of the first shaft 4 is provided with a key block 43 inserted into the key slot 62, and an inner wall of the key slot 62 is formed with a first stop and a second stop that are not coincident, and the first stop and the second stop correspond to a left-turn limit angle and a right-turn limit angle of the steering wheel. Within the angular range defined by the first and second stops (excluding the two end positions), the key block 43 is in clearance fit with the key slot 62. The design of this angular range is related to the stiffness profile of the torsion bar 7. In this angular range, both the first shaft 4 and the third shaft 6 are torque transmitting via the torsion bar 2, i.e. the first shaft 4 and the third shaft 6 rotate close to synchronously. Because the deformed stroke of the torsion bar 2 exists, the third shaft 6 actually lags behind the first shaft 4 by the degree of the lag determined by the signal transmission rate of the torque angle sensor 10, the processing time of the controller, and the response time of the motor 2.

In a manual steering mode, the first shaft 4 transmits hand input torque to the third shaft 6 through the torsion bar 7, the torque corner sensor 10 transmits detected angle signals to the controller, the controller outputs target current to the motor 2 according to a pre-calibrated power-assisted curve, the motor 2 drives the output shaft 1 through the speed reducing mechanism 3, the third shaft 6 and the torsion bar 7, and the sum of the hand input torque and the motor auxiliary torque is used as steering torque. Under the electric control steering mode, the upper layer inputs current signals corresponding to angles, angular speeds or direct torques to the motor 2, the motor 2 drives the input shaft 1 through the speed reducing mechanism 3, the third shaft 6 and the torsion bar 7, and the output torque of the motor 2 is directly used as the steering torque.

When the torsion bar 7 deforms to cause relative movement between the first shaft 4 and the third shaft 6, the key block 43 can rotate in the key groove 62 within an angle range defined by the first stop position and the second stop position, and the steering system mechanical transmission causes a corresponding existing limit angle position of the steering wheel due to the mechanical angle limit of the rigid axle or the independent suspension knuckle position. When the steering wheel reaches the left and right limit positions, namely the key block 43 contacts with the key groove 62 at the first stop position or the second stop position, the first shaft 4 and the third shaft 6 are integrated and directly transmit steering torque to prevent further deformation of the torsion bar 7. In the manual steering mode, when the key block 43 is in contact with the key groove 62 at the first stop or the second stop, the rotational resistance of the steering wheel is increased to indicate that the extreme angular position of steering is reached.

At the limit angle position, in order to avoid motor 2 from continuously increasing output torque to cause motor 2 overload, soft limit angle calibration is carried out before the angular transmission device works, the angle calibration is consistent with the limit angle position existing in the mechanical angle limitation of the steering knuckle corresponding to the steering wheel, when the soft limit angle is reached, the damping effect of motor 2 is increased, and the great difference of the angle limit can be artificially sensed. In order to avoid damage caused by continuous deformation of the torsion bar 7 due to no soft limit before calibration, when the angle range is out of the angle range, the key block 43 and the key block 62 are in direct contact with each other to transmit steering torque and feed back sudden hand force to indicate that the angle range reaches the limit position, because the soft limit calibration is not carried out according to a normal flow, the overload condition of the motor 2 possibly exists at the limit position, and at the moment, the overload condition of the motor 2 is judged according to a preset overload current threshold value and a fault is reported.

In one embodiment, the key block 43 is a square block (rectangular block or square block), and the section of the key groove 62 is oblong (kidney-shaped) or oval. For example, when the key block 43 is a square block and the cross section of the key groove 62 is oblong, the width of the oblong cross section of the key groove 62 is larger than the length of the side of the square cross section of the key block 43, and the width of the oblong cross section of the key groove 62 is smaller than the length of the diagonal line of the square cross section of the key block 43. For another example, when the key block 43 is a square block and the cross section of the key groove 62 is an ellipse, the length of the minor axis of the ellipse cross section of the key groove 62 is longer than the side length of the square cross section of the key block 43, and the length of the minor axis of the ellipse cross section of the key groove 62 is shorter than the length of the diagonal line of the square cross section of the key block 43.

However, the key block 43 and the key groove 62 may have other more matching shapes. As long as the following conditions are satisfied:

the key block 43 is in clearance fit with the key groove 62 in an angle range defined by a first stop and a second stop (excluding two end positions), and when the key block 43 is in contact with the key groove 62 in the first stop or the second stop (when the steering wheel is turned left to reach the extreme angle position or when the steering wheel is turned right to reach the extreme angle position), the first shaft 4 is integrated with the third shaft 6 and directly transmits the steering torque.

In one embodiment, as shown in fig. 1, the speed reducing mechanism 3 is a worm gear speed reducing mechanism, the speed reducing mechanism 3 includes a worm 31 fixed or integrally formed on an output shaft of the motor 2 and a worm wheel 32 fixed or integrally formed on the third shaft 6, a housing of the motor 2 is fixed outside the housing 1, the output shaft of the motor 2 penetrates into the housing 1, and the worm 31 is engaged with the worm wheel 32.

The worm gear 32 and the third shaft 6 can be integrally machined after turning. Of course, the worm wheel 32 and the third shaft 6 may be made as separate bodies for convenient processing, and a flat key or a spline connection is made between the mating surfaces of the third shaft 6 and the worm wheel 32. The third shaft 6 is in accordance with the rotational angular speed of the worm wheel 32.

The worm 31 and the worm wheel 32 form a worm gear, i.e. a worm gear reducer. The rotational speed of the worm 31 is consistent with that of the rotor of the motor 2, the output shaft of the motor 2 and the worm 31 can be integrated, and the output shaft of the motor 2 and the worm 31 can be separated and connected through a coupling.

In one embodiment, as shown in fig. 1, the housing 1 includes a bottom shell 11 and an end cap 12 fixed to the bottom shell 11 by bolts. The first shaft 4 is rotatably supported on the end cover 12 through a first bearing 20; the second shaft 5 is rotatably supported on the bottom case 11 through a second bearing 30, and the second bearing 30 abuts against one side end face of the second bevel gear 9, so that the second bevel gear 9 is axially limited. The third shaft 6 is rotatably supported on the bottom case 11 through a third bearing 40 and a fourth bearing 50, the third bearing 40 is located on one axial side of the worm wheel 32, and the fourth bearing 50 is abutted against one side end face of the first bevel gear 8, so that the axial limit of the first bevel gear 8 is realized. The first shaft 4, the second shaft 5, and the third shaft 6 are supported by bearings, so that the first shaft 4, the second shaft 5, and the third shaft 6 can stably rotate.

The shell 11 is made into a split type, the worm wheel 32 is relatively large in diameter through bolted connection, the part above the worm wheel 32 is made into the end cover 12, the part below the worm wheel 32 is made into the bottom shell 11, and mounting hole sites are arranged on the frame through die casting and machining and are used for connecting the angle transmission device on the frame through bolts.

In one embodiment, the first bevel gear 8 and the second bevel gear 9 are straight bevel gears.

In a preferred embodiment, the motor 2, the speed reducing mechanism 3 and the torque and angle sensor 10 are all arranged at the input shaft end and are highly integrated, so that the output shaft end has a simple structure, and the maximum generalization of the output shaft structure is ensured.

In the angle transmission device of the embodiment of the invention, the motor 2 is a brushless direct current motor, the size is relatively small, the motor 2 is provided with a position control device such as a Hall sensor or a rotary transformer, the rotating speed, the position and the current signal of the motor 2 are interacted with the controller, the controllability of the angle, the rotating speed and the torque of the motor 2 is realized, the corresponding steering direction, the steering speed and the steering force are controllable, and finally the angle, the rotating speed and the steering force are output to the worm 31 through the motor 2. The controller limits the current, and meanwhile, the temperature sensor can be integrated to the brushless motor 7, so that the motor 2 is prevented from being burnt out by continuous large current under a large load or a limit position. The motor 2 and the speed reducing mechanism 3 have no locking structure, operability is guaranteed when abnormal faults such as abnormal power failure occur, the first shaft 4, the third shaft 6 and the second shaft 5 can be manually driven to rotate, and at the moment, the third shaft 6 drives the worm wheel 32, the worm 31 and the motor 2, so that the input torque is slightly increased. In addition, at this time, the limit structure of the key block 43 and the key groove 62 also plays a role of protecting the torsion bar 7, and the steering safety is improved. The controller can be integrated at the rear side cover end of the motor 2 or can be made into a split type independent from the shell of the motor 2. Therefore, the controller receiving the vehicle speed signal can control the output torque and the rotating speed of the motor 2, realize basic functions of assisting with speed, improving hand strength, actively returning to normal and the like, and continuously expand an upper layer perception and control system on the basis to realize the unmanned function of the vehicle. That is, the angle drive device is applicable to electric power steering assist, and also applicable to automatic steering (electric power steering) to realize an unmanned function.

According to the angle drive of the embodiment of the present invention, the first bevel gear 8 does not need to be selectively disengaged and engaged with the first shaft 4 when detecting the torque. The mechanism which has a complex structure and many parts and is used for selectively disconnecting and connecting can be saved, and the complexity and the production cost of the structure of the angle transmission device are reduced. The electric power-assisted angle transmission device of the embodiment is additionally provided with the motor (electric control), the torque and angle sensing device and the worm and gear speed reducing mechanism at the input position on the basis of the traditional angle transmission device. Since the angular transmission follows the input and output transmission ratio of 1, the above additional parts can also be added at the output position. That is, in another embodiment, the second shaft is an input shaft and the first shaft is an output shaft.

In addition, the embodiment of the invention also provides a steering system which comprises the angle transmission device of the embodiment.

In addition, the embodiment of the invention also provides a vehicle which comprises the angle transmission device of the embodiment.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. An angle transmission device is characterized by comprising a shell, a motor, a speed reducing mechanism, a first shaft, a second shaft, a third shaft, a torsion bar, a first bevel gear, a second bevel gear and a torque and angle sensor for detecting the torque and the rotation angle of the first shaft, the speed reducing mechanism, the first shaft, the second shaft, the third shaft, the torsion bar, the first bevel gear and the second bevel gear are arranged in the shell, the first shaft, the second shaft and the third shaft are rotatably supported in the shell, the first end of the first shaft penetrates out of the shell, the torsion bar is fixed between the second end of the first shaft and the first end of the third shaft, the first shaft, the torsion bar and the third shaft are coaxially arranged, the first bevel gear is fixed at the second end of the third shaft, the first end of the second shaft penetrates out of the shell, and the second bevel gear is fixed at the second end of the second shaft;

the first shaft is an input shaft, and the second shaft is an output shaft;

the speed reducing mechanism is connected between the motor and a third shaft, and the motor drives the third shaft to rotate through the speed reducing mechanism;

a key groove is formed in the first end of the third shaft, a key block inserted in the key groove is arranged at the second end of the first shaft, and a first stop position and a second stop position which are not overlapped are formed on the inner wall of the key groove;

When the torsion bar is deformed to cause relative movement of the first shaft and the third shaft, the key block can rotate in the key slot within an angle range limited by the first stop position and the second stop position, and when the key block is in contact with the key slot at the first stop position or the second stop position, the first shaft and the third shaft are integrated and directly transmit steering torque to prevent further deformation of the torsion bar;

in the manual steering mode, when the key block is in contact with the key groove at the first stop position or the second stop position, the rotation resistance of the steering wheel is increased to indicate that the extreme steering position is reached.

2. The angle drive of claim 1, wherein the first end of the torsion bar is connected to the first shaft by a spline or a cross pin, and the second end of the torsion bar is connected to the third shaft by a spline or a cross pin.

3. The angle drive of claim 1, wherein the first shaft has a first splined bore formed therein, and the first end of the torsion bar has a first external spline received in the first splined bore;

4. The angle drive of claim 3, wherein the portion of the torsion bar located between the first and second external splines forms a reduced diameter section having an outer diameter smaller than the outer diameter of the first and second external splines, and an annular gap is formed between the outer periphery of the reduced diameter section and the inner wall of the first splined bore to provide a space for deformation of the torsion bar.

5. The angle drive of claim 1, wherein the first end of the input shaft is provided with a third external spline and a bolt-limiting ring groove, and the input shaft is connected to the gimbal assembly at the lower end of the steering column via the third external spline and the bolt-limiting ring groove.

6. The angle drive of claim 1, wherein the key block is a square block and the keyway has an oblong or oval cross-section.

7. The angle drive of claim 1, wherein the speed reduction mechanism includes a worm fixed to or integrally formed on an output shaft of the motor, a housing of the motor being fixed to an outside of the housing, the output shaft of the motor penetrating into the housing, and a worm wheel fixed to or integrally formed on the third shaft, the worm being engaged with the worm wheel.

8. The angle drive of claim 7, wherein the housing includes a bottom shell and an end cap secured to the bottom shell;

9. The angle drive of claim 1, wherein the torque angle sensor includes a magnetic ring fixed to an outer periphery of the first shaft and rotating with the first shaft, a magnetic ring housing fixed to the housing, and a magnetic reluctance disposed around the magnetic ring and fixed within the magnetic ring housing.

10. A steering system comprising an angle drive as claimed in any one of claims 1 to 9.

11. A vehicle, characterized by comprising an angle drive according to any one of claims 1 to 9.