CN215154991U

CN215154991U - Rack-assisted steer-by-wire system and rack-assisted steering device

Info

Publication number: CN215154991U
Application number: CN202120486344.3U
Authority: CN
Inventors: 张凯; 丁能根; 沈良纯; 邓伟文
Original assignee: Nanjing Jingweida Automobile Technology Co ltd
Current assignee: Nanjing Jingweida Automobile Technology Co ltd
Priority date: 2021-03-05
Filing date: 2021-03-05
Publication date: 2021-12-14
Anticipated expiration: 2031-03-05

Abstract

The utility model discloses a rack-assisted steer-by-wire system and a rack-assisted steering device, wherein the steering system comprises a steering wheel (7), a steering column (6), a steering gear (2), a tie rod (1) and a steering power-assisted device arranged on the steering gear (2); the power steering device (3) comprises a power steering device shell, a power steering motor (301), a power steering transmission mechanism arranged in the power steering device shell, a power steering gear shaft (310) and a rotation angle sensor (307) arranged on the outer side of the power steering gear shaft (310); the steering power assisting device shell is fixed with the steering gear shell (201), and the steering power assisting gear shaft (310) is in transmission fit with the steering gear rack (202). The utility model discloses simple structure, occupation space are little, with low costs, possess power assisted steering mode and drive-by-wire mode, can satisfy senior driving assistance system and autopilot system's the demand that turns to.

Description

Rack-assisted steer-by-wire system and rack-assisted steering device

Technical Field

The utility model belongs to the technical field of the auto steering technique and specifically relates to a rack helping hand formula a steering system and rack helping hand formula turn to device with drive-by-wire function is related to.

Background

An Electric Power Steering (EPS) technology is a new technology in the field of automobile Steering in the last decade, and has been developed greatly abroad, and the EPS is also a research hotspot in the domestic Steering system industry at present. The EPS platform based on can extend and develop the steer-by-wire system, do not have coherent and direct mechanical connection between steering wheel and the steering drive mechanism, can provide power assisted steering through steering wheel corner signal, moment of torsion signal, realize the motion control of relevant part through the electric signal route promptly. The EPS is used as a safety piece of an automobile, and the performance of the EPS is directly related to the safety reliability of automobile driving and the operation portability and sensitivity of a driver. When the automobile is steered under different automobile conditions, the electronic controller controls the power-assisted steering motor to provide required auxiliary power, so that the effects of stable operation, light steering and safe driving are achieved, and a driver can feel comfortable when driving. The product has the characteristics of compact structure, energy conservation, environmental protection and the like, and is a trend of the power-assisted steering development of automobiles. The electric power steering system is further classified into a column-type electric power steering system (C-EPS), a pinion-type electric power steering system (P-EPS), and a rack-type electric power steering system (R-EPS).

A tubular column type electric power steering system (C-EPS for short) is arranged on a tubular column at the lower side of a steering wheel, steering can be transmitted to a steering gear through a universal joint, a transmission shaft and other components, the transmission efficiency is low, and the response time is relatively slow; the pinion type electric power steering system (P-EPS for short) has a complex internal structure and a small transmission ratio design range, occupies a large space, is often arranged at the joint of a steering column and a steering gear, is close to a cab and an engine, and often gives way to the driving space and the engine arrangement; the conventional rack type electric power steering system (R-EPS) is limited by the limitation of insufficient transmission ratio required by spatial arrangement, and usually one part is damaged, so that the whole steering gear assembly and the whole tie rod assembly need to be replaced, so that the use cost is high.

With the continuous development of automotive electronics, smart car systems such as Advanced Driving Assistance Systems (ADAS) and Automatic Driving Systems (ADS) require shorter and better response time of a steering system, and can perform autonomous steering on a vehicle, that is, steering is applied to vehicle wheels without manually rotating a steering wheel. Meanwhile, the design of the automobile also pursues large driving space and smaller steering occupation space, and the new energy automobile can accommodate more sensors, power battery equipment and the like.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the purpose satisfies the steering demand of senior driving assistance system (ADAS) and Automatic Driving System (ADS), provides one kind and possesses drive-by-wire steering function, simple structure, with low costs, the high rack helping hand formula a steering system and turn to the device of security to solve the problem that prior art exists.

In order to achieve the above purpose, the utility model adopts the technical scheme that:

a rack-assisted steer-by-wire system comprises a steering wheel, a steering column and a steering gear which are sequentially connected from top to bottom, wherein two ends of the steering gear are respectively connected with a tie rod; the steering gear comprises a steering gear shell and a steering gear rack, and a steering power assisting device is further mounted on the steering gear shell;

the power steering device comprises a power steering device shell, a power steering motor fixed on the power steering device shell, a power steering transmission mechanism arranged in the power steering device shell and in transmission fit with the power steering motor, a power steering gear shaft connected with the power steering transmission mechanism and a corner sensor arranged on the outer side of the power steering gear shaft; the steering power assisting device shell is fixed with the steering gear shell, and the steering power assisting gear shaft is in transmission fit with the steering gear rack.

Furthermore, a first section of tooth part and a second section of tooth part are arranged on the steering gear rack, and the first section of tooth part is in meshing transmission with a gear shaft connected to the lower end of the steering column; and the second section of tooth part is in meshed transmission with the tooth part on the power steering gear shaft.

In a preferred embodiment, the power steering gear is a worm gear. The worm gear and worm transmission mechanism comprises a worm gear and a worm, the worm is coaxially and fixedly connected with an output shaft of the power steering motor, the worm gear is coaxially fixed with the power steering gear shaft, and the power steering gear shaft is rotatably connected in the power steering device shell.

Further, the steering gear housing includes a main housing and a half-half housing that clamp and fixedly connect the steering gear housing, a second section tooth portion of the steering gear rack is located between the main housing and the half-half housing, and the steering gear rack is engaged with a tooth portion of the steering gear shaft rotatably connected in the main housing.

In a preferred embodiment, the first section of teeth is straight and meshes with a pinion shaft at the lower end of the steering column. The second section of tooth part is helical tooth and is meshed with the steering power-assisted gear shaft. In position, the second segment of the tooth portion is located in the middle of the steering rack.

Furthermore, a free gap adjusting device for maintaining a radial meshing position gap between the steering gear rack and the power steering gear shaft is further arranged on the half-half casing.

Still further, the free clearance adjusting device comprises a bearing bush seat movably arranged in the half-half shell along the radial direction of the steering gear rack, a nut in threaded connection with the half-half shell, and an elastic piece pre-tightened between the nut and the bearing bush seat; the bearing bush seat is positioned on the other side opposite to the steering power-assisted gear shaft, a bearing bush is arranged on the end face, facing the steering gear rack, of the bearing bush seat, and the bearing bush clamps the steering gear rack in the radial direction under the action of the pretightening force of the elastic piece.

Furthermore, a through hole is formed between the main shell and the half-half shell after the main shell and the half-half shell are matched, and the through hole is coaxially clamped and matched with the cylindrical surface of the steering gear shell; the axis of the output shaft of the power steering motor is parallel to the axis of the steering gear rack, and the axis of the power steering gear shaft is vertical to the axis of the steering gear rack; the main casing body with half ha fu casing passes through screw fixed connection, just the main casing body with be equipped with certain clearance between the fitting surface of half ha fu casing.

Further, the power steering gear shaft is rotatably connected in the main housing through a first bearing arranged at the lower part and a second bearing arranged at the upper part; the second bearing is fixed on the upper part of the main shell through a bearing seat, and the bearing seat is detachably connected with the main shell; the upper end surface of the bearing seat is also provided with a groove for accommodating the corner sensor, and the upper part of the power steering gear shaft penetrates through the end part of the bearing seat and is provided with a magnet matched with the corner sensor; the upper end of the bearing seat is also detachably connected with an upper cover of a corner sensor.

Further, the bearing seat comprises an upper seat body and a lower seat body which are matched and connected, the lower seat body is fixed with the main shell through a screw, and the upper seat body is fixed with the lower seat body through a screw; the second bearing is fixed between the upper seat body and the lower seat body, and the upper part of the steering power-assisted gear shaft is supported on the second bearing through a clamping nut in threaded connection; the upper cover of the rotation angle sensor is fixed with the upper seat body through screws.

According to the utility model discloses a rack power-assisted steering device, including the power steering device casing, fix on the power steering device casing power steering motor, set up in the power steering device casing and with the power steering motor transmission complex power steering transmission mechanism, with the power steering gear shaft that the power steering transmission mechanism links to each other and set up the corner sensor in the power steering gear shaft outside; the steering power-assisted device shell is used for being matched and fixed with the steering gear shell, and the steering power-assisted gear shaft is used for being in transmission fit with the steering gear rack; the steering power assisting device shell comprises a main shell and a half-half shell which are used for clamping and fixedly connecting the steering device shell.

The utility model discloses a rack helping hand formula drive-by-wire steering system, be used for coming driving motor to provide the helping hand that turns to with the controller that turns to the helping hand motor electricity and be connected through the setting, can make this steering system possess two kinds of mode at least: a power-assisted steering mode and a steer-by-wire mode.

A steering power-assisted mode: when a vehicle is in a driver operation driving mode, when a driver rotates a steering wheel to steer, a steering angle sensor outputs a steering angle signal, a controller is utilized to receive the steering angle signal, a target power-assisted steering torque is obtained through calculation according to the current steering wheel angle, a power-assisted steering motor of a power-assisted steering device is controlled to output a power torque, the power torque is transmitted to a power-assisted steering gear shaft after reaching the target power-assisted steering torque through the transmission of a power-assisted steering transmission mechanism, the torque of the power-assisted steering gear shaft is converted into the thrust of a steering gear rack, and a steering wheel is driven through tie rods connected to the left end and the right end of the steering gear rack, so that the power-assisted steering is realized;

steer-by-wire mode: when the vehicle is in a steer-by-wire mode, the vehicle control unit sends a steer-by-wire command to a vehicle CAN bus through a CAN message, the controller is used for receiving the CAN message and normally responding to the steer-by-wire quantity sent by the vehicle control unit to automatically apply steering, the controller drives the motor to output torque to drive the power-assisted steering transmission mechanism and the power-assisted steering gear shaft to rotate, the output torque is converted into thrust of a steering gear rack, and the tie rods connected to the left end and the right end of the steering gear rack drive the steering wheels to realize steer-by-wire.

The transmission mechanism of the power steering device of the utility model can adopt a worm gear transmission mechanism, and combines a gear shaft and a rack for transmission, the whole transmission ratio is large, the efficiency is high, the occupied space is small, and the power steering device can be arranged in the middle of a steering gear shell; meanwhile, the steering power assisting device adopts the matching of the shell in the Haff mechanism form and the axle hole of the steering gear shell, if a certain part in the steering power assisting device is damaged, the shell can be independently replaced, and the steering gear assembly and the tie rod assembly do not need to be replaced, so that the steering power assisting device has certain detachability and the use cost is reduced.

Due to the adoption of the technical scheme, the utility model discloses following beneficial effect has been reached:

1) the utility model discloses rack power-assisted steer-by-wire system can realize the steer-by-wire function, realizes independently turning to for the vehicle that possesses senior driving assistance system (ADAS) and Automatic Driving System (ADS).

2) The utility model discloses a power steering device has adopted the design of half mechanism, possesses certain independent replaceability, reduces consumer use cost.

3) The utility model discloses a steering power-assisted that rack helping hand formula steer-by-wire system produced directly acts on the steering gear rack, and the helping hand response is fast.

4) The utility model discloses a power steering device adopts worm gear, rack and pinion drive mechanism, simple structure, and is with low costs, and the drive ratio is big, easily satisfies drive-by-wire and power assisted steering torque demand with the motor of less moment of torsion.

Drawings

Fig. 1 is a layout view of a rack assist type steer-by-wire system according to an embodiment of the present invention.

Fig. 2 is another layout view of a rack-assist steer-by-wire system according to an embodiment of the present invention (excluding a steering wheel, a steering column, and a partial housing).

Fig. 3 is a perspective view of a steering assist device according to an embodiment of the present invention.

Fig. 4 is a front view of a steering assist device according to an embodiment of the present invention.

Fig. 5 is a sectional view a-a of fig. 4.

Fig. 6 is a sectional view B-B of fig. 4.

Fig. 7 is an enlarged view of a portion C in fig. 5.

Fig. 8 is a schematic view of an operating principle of a rack assist type steer-by-wire system according to an embodiment of the present invention.

In the drawings:

1-a tie rod; 2-a diverter; 3-a steering assist device; 4-a torque sensor; 5-a gear shaft; 6-a steering column; 7-a steering wheel;

201-a diverter housing; 202-a steering gear rack; 203-free gap adjustment means;

301-steering assist motor; 302-a coupling assembly; 303-worm; 304-a sealing cover; 305 — a controller; 306-upper cover of rotation angle sensor; 307-rotation angle sensor; 308-bearing seat; 309-tightening the nut; 310-a steering assist gear shaft; 311-a retainer ring; 312-a worm gear; 313 — a main housing; 314-needle bearings; 315-half-huff shell; 316-bearing bush seat; 317, bearing bush; 318-pre-tightening spring; 319 — seal pin; 320-a nut; 321-tightening the nuts; 322-O-ring.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and obviously, the described embodiments are only some embodiments, not all embodiments, of the present invention. Based on the embodiments of the present invention, all other embodiments obtained under the premise of equivalent changes and modifications by those skilled in the art should belong to the protection scope of the present invention.

Referring to fig. 1, the present embodiment provides a rack-assist steer-by-wire system, which includes a steering wheel 7, a steering column 6 and a steering gear 2, which are sequentially connected from top to bottom, wherein two ends of the steering gear 2 are respectively connected to tie rods 1; the steering gear 2 comprises a steering gear shell 201 and a steering gear rack 202, and the steering gear shell 201 is also provided with a power steering device 3; the power steering device 3 comprises a power steering device shell, a power steering motor 301 fixed on the power steering device shell, a power steering transmission mechanism arranged in the power steering device shell and in transmission fit with the power steering motor 301, a power steering gear shaft 310 connected with the power steering transmission mechanism, and a rotation angle sensor 307 arranged outside the power steering gear shaft 310; the power steering housing is fixed with the steering gear housing 201, and the power steering gear shaft 310 is in transmission fit with the steering gear rack 202. The utility model discloses in, in order to make a steering system and the function that turns to the device CAN realize the steer-by-wire, increased the controller 305 of being connected with the power assisted steering motor 301 electricity in the power assisted steering device casing in concrete use, controller 305 still with whole car CAN bus communication, and receive corner sensor 307, torque sensor 5's signal. Of course, the controller 305 is not limited to being provided in the steering assist device housing, and may be provided in other locations of the vehicle, without affecting the use of the rack assist type steer-by-wire system and the steering device.

The utility model provides a rack assist steering system, its power steering device 3 arranges at the middle part of steering gear 2, and the anterior arrangement of current vehicle steering gear is mostly engine or the great space of gearbox reservation usually, also can arrange in a flexible way other optional positions at steering gear casing 201 as required.

Referring to fig. 2, the steering rack 202 is provided with a first section of tooth portion 2021 and a second section of tooth portion 2022, and the first section of tooth portion 2021 is in meshing transmission with the gear shaft 5 connected to the lower end of the steering column 6; the second-stage teeth 2022 are in meshing transmission with the teeth on the steering gear shaft 310. In this embodiment, the gear shaft 5 is further provided with a torque sensor 4. The first-stage tooth portion 2021 is preferably straight tooth, and the second-stage tooth portion 2022 is preferably helical tooth. In position, the second segment of teeth 2022 in this embodiment is located in the middle of the steering rack 202.

Referring to fig. 3 to 6, in the present embodiment, the power steering transmission mechanism is a worm gear transmission mechanism. The worm gear and worm transmission mechanism comprises a worm wheel 312 and a worm 303, the worm 303 is coaxially and fixedly connected with an output shaft of the power steering motor 301 through a coupler 302, the worm 303 is supported in a shell of the power steering device through bearings at two ends, and a sealing cover 304 is arranged at one end far away from the power steering motor 301. The worm wheel 312 is coaxially fixed with the steering assisting gear shaft 310 and is in interference fit with the steering assisting gear shaft; the steering assist gear shaft 310 is rotatably coupled in the steering assist housing.

The steering power assisting device shell comprises a main shell 313 and a half-half shell 315 which clamp and fixedly connect the steering gear shell 201, the second section tooth part 2022 of the steering gear rack 202 is positioned between the main shell 313 and the half-half shell 315, and the steering gear rack 202 is meshed with the tooth part of the steering power assisting gear shaft 310 which is rotatably connected in the main shell 313. In order to ensure proper engagement, the half-huff housing 315 is further provided with a free gap adjusting device 203 for maintaining a gap between the steering gear rack 202 and the steering gear shaft 310 at a radially engaged position, in order to generate a radial thrust when the steering gear shaft 310 is engaged with the steering gear rack 202 during power assist.

The free play adjustment device 203 includes a shoe seat 316 movably disposed in the half-half. The pad holder 316 is located on the other side opposite to the power steering gear shaft 310, and a pad 317 is disposed on an end surface of the pad holder 316 facing the steering gear rack 202, and the pad 317 radially clamps the steering gear rack 202 under the pre-tightening force of the pre-tightening spring 318. In this embodiment, the bearing bush seat 316 and the half-half shell 315 is sealed by two O-rings 322, and the front end surface of the nut 320 and the rear end surface of the bearing bush seat 316 are sealed by one O-ring 322. Nut 320 is threadably connected to half-huff shell 315 and secured by a jam nut 321. The nut 320 has a central bore in which a sealing pin 319 is mounted, and a pre-tensioned spring 318 is located in the space formed between the shoe 316 and the nut 320. The initial bearing bush is in interference connection with the bearing bush seat 316, and the pretightening force of the pretightening spring 318 can act on the bearing bush seat to indirectly clamp the bearing bush and the rack 202 to counteract the radial thrust, so that the radial meshing position gap between the rack 202 and the gear shaft 310 is ensured; the O-shaped ring and the seal pin 319 in the sealing device can realize sealing, and the requirements of vehicle-scale dustproof and waterproof grades are met.

As shown in fig. 3, 6 and 7, a through hole is formed between the main housing 313 and the half-huff housing 315 after the main housing 313 and the half-huff housing 315 are matched, the through hole is coaxially clamped and matched with the cylindrical surface of the steering gear housing 201 and is fixedly connected with the cylindrical surface through a screw, and a certain gap δ is formed between the matching surfaces of the main housing 313 and the half-huff housing 315, and the gap δ can generate a certain pre-tightening force when the main housing 313 and the half-huff housing 315 are connected with the screw, so as to ensure that the power steering device 3 and the steering gear 2 are reliably fixed. In this embodiment, the axis of the output shaft of the steering assist motor 301 is parallel to the axis of the steering rack 202, and the axis of the steering assist gear shaft 310 is perpendicular to the axis of the steering rack 202. With this arrangement, the installation space can be saved to the maximum extent. In addition, the power steering device 3 adopts the main shell 313 and the half-half mechanism to be matched with the shaft hole of the steering gear shell 201, so that the power steering device has certain detachability, and if a certain part of the power steering device 3 is damaged, the power steering device can be independently replaced, thereby reducing the use cost of consumers. It should be noted that the housing of the power steering apparatus of the present invention is not limited to the form of clamping and fixing the main housing 313, the half-half steering gear 201 of the half mechanism to the steering gear 201, so that the structure is simpler.

Inside the steering assist device 3, a steering assist gear shaft 310 is rotatably coupled in a main housing 313 via a first bearing provided at a lower portion and a second bearing provided at an upper portion. The steering assist gear shaft 310 is provided with a limiting protrusion, and the worm wheel 312 is in interference fit with the steering assist gear shaft 310 and is limited by the upper retaining ring 311 and the lower limiting protrusion. The second bearing is fixed to the upper portion of main housing 313 through bearing housing 308, and bearing housing 308 is detachably connected to main housing 313; the upper end surface of the bearing seat 308 is also provided with a groove for arranging the rotation angle sensor 307, and the upper part of the power steering gear shaft 310 penetrates through the end part of the bearing seat 308 and is provided with a magnet matched with the rotation angle sensor 307; the upper end of the bearing block 308 is also detachably connected with an upper cover 306 of the rotation angle sensor.

The bearing block 308 comprises an upper seat body and a lower seat body which are connected in a matching manner, the lower seat body is fixed with the main shell 313 through a screw, and the upper seat body is fixed with the lower seat body through a screw; a second bearing on which the upper portion of the steering assist gear shaft 310 is supported by a union nut 309 that is screw-coupled is fixed between the upper and lower housing bodies; the upper cover 306 of the rotation angle sensor is fixed to the upper seat body by screws. In this embodiment, the first bearing is a needle bearing 314, and the second bearing is a deep groove ball bearing. Because the main housing 313, the lower housing of the bearing block 308, the upper housing, and the upper cover 306 of the rotation angle sensor are sequentially stacked and fixedly connected from bottom to top, the installation, maintenance, and detachment are very convenient.

The utility model also provides a control method of above-mentioned rack helping hand formula steer-by-wire system, control method is including turning to helping hand mode and steer-by-wire mode. When the vehicle is operated and driven by a driver, the steering system is in a steering-assisted mode, and when the vehicle is automatically driven, the steering system is in a steer-by-wire mode.

Referring to fig. 8, once the steering assist device 3 of the rack-assisted steer-by-wire system receives a steering wheel angle signal sent by a vehicle CAN bus or a torque signal sent by the torque sensor 4, the controller 305 calculates a target power-assisted steering torque according to the signal, and further controls the magnitude of the assist current of the power-assisted steering motor 301 to output a suitable motor torque, and the target power-assisted steering torque is realized by reducing the speed and increasing the torque through the worm 303 and the turbine 312. Further, the power-assisted steering torque is transmitted to the power-assisted steering gear shaft 310, the power-assisted steering gear shaft 310 is directly meshed with the steering gear rack 202, and finally the motor torque is converted into the thrust of the steering gear rack 202 to provide the power-assisted steering; the steering wheel angle sensor 307 can directly acquire the angle of the gear shaft 310 and indirectly acquire the steering movement stroke of the steering gear rack 202; the torque sensor 5 actually feeds back the torque magnitude of the steering gear assembly 2.

A steering power-assisted mode: when the rack-assist steer-by-wire system is in a fault-free steering mode, a driver rotates a steering wheel to steer when the vehicle is in a driver operation driving mode, the steering angle sensor 307 outputs a steering angle signal, the controller 305 receives the steering angle signal, calculates a target power-assisted steering torque according to a current steering wheel angle, controls a power-assisted steering motor 301 of the power-assisted steering device 3 to output a power torque, transmits the power torque to a power-assisted steering gear shaft 310 after the power torque reaches the target power-assisted steering torque through the transmission of a worm wheel 312 and a worm 303, converts the torque of the power-assisted steering gear shaft 310 into a thrust of a steering gear rack 202, and drives steering wheels through tie rods 1 connected to the left end and the right end of the steering gear rack 202 to realize power-assisted steering.

Steer-by-wire mode: when the vehicle is in a drive-by-wire mode (namely an automatic driving mode) obtained from a whole vehicle CAN bus, a whole vehicle VCU sends a drive-by-wire steering command to the vehicle CAN bus through a CAN message, the controller 305 receives the CAN message and normally responds to the drive-by-wire steering quantity sent by the whole vehicle VCU to autonomously apply steering, the controller 305 drives the motor 301 to output torque to drive the worm wheel 312, the worm 303 and the steering assisting gear shaft 310 to rotate, the output torque is converted into the thrust of the steering gear rack 202, and the steering wheel is driven through the tie rods 1 connected to the left end and the right end of the steering gear rack 202, so that the drive-by-wire steering is realized.

The utility model discloses a rack helping hand formula drive-by-wire steering system and steering device adopts ripe worm gear and rack and pinion transmission, and transmission efficiency is high, possesses more reliable steering and security to be applicable to the drive-by-wire steering system demands of vehicles such as senior driving assistance system (ADAS) and Automatic Driving System (ADS).

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention.

Claims

1. A rack-assisted steer-by-wire system is characterized by comprising a steering wheel (7), a steering column (6) and a steering gear (2) which are sequentially connected from top to bottom, wherein two ends of the steering gear (2) are respectively connected with a tie rod (1); the steering gear (2) comprises a steering gear shell (201) and a steering gear rack (202), and a steering power assisting device (3) is further mounted on the steering gear shell (201);

the power steering device (3) comprises a power steering device shell, a power steering motor (301) fixed on the power steering device shell, a power steering transmission mechanism arranged in the power steering device shell and in transmission fit with the power steering motor (301), a power steering gear shaft (310) connected with the power steering transmission mechanism, and a rotation angle sensor (307) arranged on the outer side of the power steering gear shaft (310); the steering power assisting device shell is fixed with the steering gear shell (201), and the steering power assisting gear shaft (310) is in transmission fit with the steering gear rack (202).

2. The rack-assist steer-by-wire system according to claim 1, wherein the steering rack (202) is provided with a first section of teeth (2021) and a second section of teeth (2022), and the first section of teeth (2021) is in meshing transmission with a gear shaft (5) connected to the lower end of the steering column (6); the second-section tooth part (2022) is in meshed transmission with a tooth part on the power steering gear shaft (310).

3. The rack-assist steer-by-wire system according to claim 1, wherein the power steering gear is a worm gear and worm gear, the worm gear and worm gear comprises a worm wheel (312) and a worm (303), the worm (303) is coaxially and fixedly connected with an output shaft of the power steering motor (301), the worm wheel (312) is coaxially and fixedly connected with the power steering gear shaft (310), and the power steering gear shaft (310) is rotatably connected in the power steering gear housing.

4. The rack assist by wire steering system according to claim 2, wherein the steering assist device housing includes a main housing (313) and a half-half housing (315) that clamp and fixedly connect the steering gear housing (201), the second-segment teeth (2022) of the steering gear rack (202) are located between the main housing (313) and the half-.

5. The rack-assist steer-by-wire system according to claim 4, wherein said half-half housing (315) is further provided with a free gap adjusting means (203) for maintaining a gap in a radial meshing position between said steering rack (202) and said steering assist gear shaft (310).

6. The rack-assist steer-by-wire system according to claim 5, wherein the free play adjusting means (203) comprises a shoe seat (316) movably provided in the half-half housing (315) in a radial direction of the steering rack bar (202), and an elastic member pre-tightened between the nut (320) and the shoe seat (316); the bearing bush seat (316) is located on the other side opposite to the power steering gear shaft (310), a bearing bush (317) is arranged on the end face, facing the steering gear rack (202), of the bearing bush seat (316), and under the action of the pre-tightening force of the elastic piece, the bearing bush (317) clamps the steering gear rack (202) in the radial direction.

7. The rack-assisted steer-by-wire system according to claim 4, wherein a through hole is formed between the main housing (313) and the half-shell (201; the axis of the output shaft of the power steering motor (301) is parallel to the axis of the steering gear rack (202), and the axis of the power steering gear shaft (310) is perpendicular to the axis of the steering gear rack (202); the main shell (313) is fixedly connected with the half-half shell (315) through screws, and a certain gap is formed between matching surfaces of the main shell (313) and the half-half shell (315).

8. The rack assist-type steer-by-wire system according to claim 4, wherein said steering assist gear shaft (310) is rotatably coupled in said main housing (313) through a first bearing provided at a lower portion and a second bearing provided at an upper portion; the second bearing is fixed on the upper part of the main shell (313) through a bearing seat (308), and the bearing seat (308) is detachably connected with the main shell (313); the upper end surface of the bearing seat (308) is also provided with a groove for arranging the rotation angle sensor (307), and the upper part of the power steering gear shaft (310) penetrates through the end part of the bearing seat (308) and is provided with a magnet matched with the rotation angle sensor (307); the upper end of the bearing seat (308) is also detachably connected with an upper cover (306) of the corner sensor.

9. The rack-assist type steer-by-wire system according to claim 8, wherein said bearing housing (308) comprises an upper housing and a lower housing which are cooperatively connected, said lower housing being fixed to said main housing (313) by a screw, said upper housing being fixed to said lower housing by a screw; the second bearing is fixed between the upper seat body and the lower seat body, and the upper part of the steering power-assisted gear shaft (310) is supported on the second bearing through a clamping nut (309) in threaded connection; the upper cover (306) of the rotation angle sensor is fixed with the upper seat body through screws.

10. A rack-assist type steering device is characterized by comprising a steering assisting device shell, a steering assisting motor (301) fixed on the steering assisting device shell, a steering assisting transmission mechanism arranged in the steering assisting device shell and in transmission fit with the steering assisting motor (301), a steering assisting gear shaft (310) connected with the steering assisting transmission mechanism and a corner sensor (307) arranged on the outer side of the steering assisting gear shaft (310); the steering power assisting device shell is used for being matched and fixed with a steering gear shell (201), and the steering power assisting gear shaft (310) is used for being in transmission fit with a steering gear rack (202); the steering power assisting device shell comprises a main shell (313) and a half-half shell (315) which are used for clamping and fixedly connecting the steering gear shell (201).