CN213442759U

CN213442759U - Electric power steering system of large-scale commercial vehicle

Info

Publication number: CN213442759U
Application number: CN202022663850.3U
Authority: CN
Inventors: 王静; 李连祥; 钟玲玲; 袁鲁平; 向坤; 陈顺
Original assignee: Anhui Defu Steering System Inc
Current assignee: Anhui Defu Steering System Inc
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2021-06-15
Anticipated expiration: 2030-11-17

Abstract

The utility model discloses an electronic power assisted steering system of large-scale commercial car, including steering drive shaft, the knuckle arm, telescopic electronic power assisted steering device and steering electronic control unit, telescopic electronic power assisted steering device includes the input shaft of being connected with steering drive shaft, the big gear wheel that turns to with input shaft, with the steering pinion gear that turns to gear wheel meshing, the helping hand motor, the helping hand pinion of being connected with the helping hand motor, with the meshing of helping hand pinion and with the helping hand gear wheel of little gear wheel coaxial coupling, ball screw mechanism of being connected with the helping hand gear wheel and the outer pull rod that turns to that is connected with the knuckle arm with ball screw mechanism. The electric power steering system of the large commercial vehicle has high integration level, is convenient to arrange, and has no complex oil circuit and oil circuit accessories needing to be assembled; the steering function requirements of auxiliary driving and automatic driving can be met.

Description

Electric power steering system of large-scale commercial vehicle

Technical Field

The utility model belongs to the technical field of vehicle steering system, specifically speaking, the utility model relates to an electronic power assisted steering system of large-scale commercial car.

Background

The electric power-assisted steering system of the new energy bus is the development direction of pure electric, hydrogen energy and other new energy city public transport and highway bus steering systems, and is a steering execution part capable of realizing the complete automatic driving and advanced driving auxiliary functions of vehicles, such as vehicle queue driving, lane keeping function, lane changing auxiliary function and the like. The electric power-assisted steering system of the new energy bus can be applied to new energy city buses and highway buses with steering single-shaft loads not greater than 7500 kgf.

The existing new energy bus steering system is basically a hydraulic power-assisted steering system or an electric hydraulic power-assisted steering system, the oil ways of the two steering systems are difficult to arrange and install, the later maintenance cost is high, and certain environmental pollution can be caused due to the need of using hydraulic oil. In addition, these two hydraulic steering systems cannot fully meet the steering function requirements of driving assistance or automatic driving.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides an electronic power assisted steering system of large-scale commercial car, the purpose realizes the complete autopilot of vehicle and senior driving assistance function.

In order to realize the purpose, the utility model discloses the technical scheme who takes does: the electric power-assisted steering system of the large-scale commercial vehicle comprises a steering transmission shaft, a steering knuckle arm and a telescopic electric power-assisted steering device, wherein the telescopic electric power-assisted steering device comprises an input shaft connected with the steering transmission shaft, a steering large gear connected with the input shaft, a steering small gear meshed with the steering large gear, a power-assisted motor, a power-assisted small gear connected with the power-assisted motor, a power-assisted large gear meshed with the power-assisted small gear and coaxially connected with the steering small gear, a ball screw mechanism connected with the power-assisted large gear and a steering outer pull rod connected with the ball screw mechanism and connected with the steering knuckle arm.

The telescopic electric power steering assisting device further comprises a shell assembly, the assisting motor is arranged on the shell assembly, and the ball screw mechanism, the steering large gear, the steering small gear, the assisting small gear and the assisting large gear are located inside the shell assembly.

The ball screw mechanism comprises a screw connected with the steering gear wheel, a nut matched with the screw, a telescopic rod connected with the nut and a guide rod guiding the nut, and the telescopic rod is connected with the steering outer pull rod through a joint bearing.

The guide bar sets up two, be provided with two oilless axle sleeves on the nut, each guide bar passes an oilless axle sleeve respectively.

The electric power-assisted steering system of the large-scale commercial vehicle has the advantages of small number of parts, low cost, high integration level, convenient arrangement and no complex oil circuit and oil circuit accessories needing to be assembled; no hydraulic oil circuit exists, the oil leakage problem does not exist, and the environmental pollution is not caused; the steering function requirements of auxiliary driving and automatic driving can be met.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a schematic structural view of an electric power steering system of a large commercial vehicle according to the present invention;

FIG. 2 is a schematic diagram of the electric power steering system of the large commercial vehicle in a normal driving mode;

FIG. 3 is a schematic diagram of the electric power steering system of the large commercial vehicle operating in the intelligent driving mode;

FIG. 4 is a schematic diagram of the electric power steering system of the large commercial vehicle according to the present invention when the steering wheel is turned right;

FIG. 5 is a schematic diagram of the electric power steering system of the large commercial vehicle according to the present invention when the steering wheel is turned left;

FIG. 6 is a schematic structural view of a telescopic electric power steering apparatus;

fig. 7 is a schematic view of the internal structure of the telescopic electric power steering apparatus;

FIG. 8 is a schematic view of the engagement of the nut with the guide bar;

fig. 9 is a schematic structural view of the speed reducing mechanism;

labeled as: 1. a steering wheel; 2. a steering column; 3. a steering transmission shaft; 4. a steering electronic control unit; 5. a telescopic electric power steering apparatus; 501. a booster motor; 502. a telescopic rod; 503. an outer tie rod for steering; 504. a steering bull gear; 505. a steering pinion gear; 506. a booster pinion; 507. a power-assisted gearwheel; 508. a first housing; 509. a second housing; 510. a housing connection pipe; 511. a lead screw; 512. a nut; 513. an oilless shaft sleeve; 514. a guide bar; 516. an input shaft; 522. an input shaft; 6. a knuckle arm; 7. a tie rod; 8. and (7) wheels.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings, for the purpose of helping those skilled in the art to understand more completely, accurately and deeply the conception and technical solution of the present invention, and to facilitate its implementation.

It should be noted that, in the following embodiments, the "first" and "second" do not represent an absolute distinction relationship in structure and/or function, nor represent a sequential execution order, but merely for convenience of description.

As shown in fig. 1 to 9, the present invention provides an electric power steering system for a large commercial vehicle, comprising a steering wheel 1, a steering column 2, a steering transmission shaft 3, a knuckle arm 6 and a telescopic electric power steering device 5, wherein the telescopic electric power steering device 5 comprises a torque angle sensor, an input shaft 516 connected with the steering transmission shaft 3, a large steering gear 504 connected with the input shaft 516, a small steering gear 505 engaged with the large steering gear 504, a power motor 501, a small power gear 506 connected with the power motor 501, a large power gear 507 engaged with the small power gear 506 and coaxially connected with the small steering gear 505, a ball screw mechanism connected with the large power gear 507, and an outer steering rod 503 connected with the ball screw mechanism and connected with the knuckle arm 6, the outer steering rod 503 is rotatably connected with the knuckle arm 6 of one of the wheels, the knuckles of the two wheels are rotatably connected to a tie rod 7, and the tie rod 7 causes the two wheels to steer synchronously.

Specifically, as shown in fig. 1 to 7 and 9, the upper end of the steering column 2 is fixedly connected to the steering wheel 1, the lower end of the steering column 2 is fixedly connected to the upper end of the steering transmission shaft 3, the lower end of the steering transmission shaft 3 is fixedly connected to the input shaft 516, the steering large gear 504 is coaxially and fixedly connected to the input shaft 516, and the torque angle sensor is disposed on the input shaft 516. The steering pinion 505 is engaged with the steering bull gear 504 to form a speed increasing mechanism, and the diameter of the steering pinion 505 is smaller than that of the steering bull gear 504. The steering pinion 505 is coaxially and fixedly connected with the power-assisted gearwheel 507, the power-assisted pinion 506 is meshed with the power-assisted gearwheel 507 to form a speed reduction mechanism, the diameter of the power-assisted pinion 506 is smaller than that of the power-assisted gearwheel 507, the power-assisted pinion 506 is fixedly connected with a motor shaft of the power-assisted motor 501, and the axis of the power-assisted pinion 506 is spatially perpendicular to that of the input shaft 516. The telescopic electric power steering assisting device 5 further comprises a housing assembly, the assisting motor 501 is arranged on the housing assembly, and the ball screw mechanism, the steering large gear 504, the steering small gear 505, the assisting small gear 506 and the assisting large gear 507 are located inside the housing assembly. The housing assembly includes a first housing 508, a second housing 509, and a housing connection pipe 510, the housing connection pipe 510 has a housing structure with a certain length and a hollow interior, and the first housing 508 and the second housing 509 are respectively fixedly connected to opposite ends of the housing connection pipe 510 in a length direction. The power-assisted motor 501 is fixedly connected with the first housing 508, the input shaft 516 is rotatably arranged on the first housing 508, the steering large gear 504, the steering small gear 505, the power-assisted small gear 506 and the power-assisted large gear 507 are positioned inside the first housing 508, the telescopic rod 502 penetrates through the second housing 509, one end of the telescopic rod 502 is positioned inside the housing connecting pipe 510, and the other end of the telescopic rod 502 is positioned outside the second housing 509. The steering and power-assisted functions are respectively realized by adopting two pairs of gear pairs, and the steering pinion 505, the steering bull gear 504, the power-assisted pinion 506 and the power-assisted bull gear 507 are hyperboloid gears, so that the steering gear has the advantages of compact structure, high gear rigidity, stable transmission, small size of a relative gear and light weight.

As shown in fig. 1 to 8, the ball screw mechanism includes a screw 511 connected to the steering large gear 504, a nut 512 engaged with the screw 511, an expansion link 502 connected to the nut 512, and a guide rod 514 guiding the nut 512, and the expansion link 502 is connected to the outer tie rod 503 through a joint bearing. The casing connecting pipe 510 is a cylinder, the screw 511 and the casing connecting pipe 510 are coaxially arranged, the screw 511 is rotatably arranged inside the casing connecting pipe 510, the screw 511 and the steering gear 504 are coaxially and fixedly connected, the screw 511 and the nut 512 form a screw drive, the nut 512 is arranged inside the casing connecting pipe 510, the nut 512 is fixedly connected with one end of the telescopic rod 502, the telescopic rod 502 is a cylinder, and the telescopic rod 502, the screw 511 and the nut 512 are coaxially arranged. After the screw 511 rotates, the nut 512 drives the telescopic rod 502 to move along the axial direction synchronously, and the telescopic rod 502 drives the knuckle arm 6 to rotate through the outer steering pull rod 503, so that the deflection of the wheels is realized, and the steering of the vehicle is further realized.

The steering function is as follows: as shown in fig. 4, when the driver steers the steering wheel 1 to the right to steer the vehicle, the input shaft 516 is driven to rotate clockwise, the steering large gear 504 integrated with the input shaft 516 rotates clockwise, the steering small gear 505 is driven to rotate counterclockwise through gear engagement, and the steering small gear 505 is integrated with the lead screw 511, so that the lead screw 511 is driven to rotate counterclockwise and the nut 512 and the telescopic rod 502 are shortened inwards, thereby driving the wheels to rotate to the right; as shown in fig. 5, when the driver steers the steering wheel 1 to the left to steer the vehicle, the input shaft 516 is driven to rotate counterclockwise, the large steering gear 504 integrated with the input shaft 516 rotates counterclockwise, the small steering gear 505 is driven to rotate clockwise through gear engagement, and the small steering gear 505 and the ball screw 511 are integrated, so that the screw 511 is driven to rotate clockwise, the nut 512 and the telescopic rod 502 are extended outwards, and the wheels are driven to rotate to the left.

The number of turns of the steering wheel 1 can be adjusted by setting the gear ratio of the steering gear pair so as to adapt to the requirements of different vehicles on the number of turns of the steering wheel 1, the larger the gear ratio is, the smaller the number of turns of the steering wheel 1 is, and otherwise, the smaller the gear ratio is, the more the number of turns of the steering wheel 1 is. Since the steering gear pair is speed-increasing and torque-reducing, when the steering torque for the driver to operate the steering wheel 1 passes through the gear pair, the torque applied to the steering pinion 505 is reduced by the gear ratio, and therefore the gear pair is small in stress, long in service life, reliable and durable.

The power assisting function is as follows: as shown in fig. 4, when a driver steers the steering wheel 1 to steer the vehicle to the right, the input shaft 516 is driven to rotate clockwise, the torque angle sensor welded with the input shaft 516 sends the acquired steering force and steering angle signals to the steering electronic control unit 4(ECU), after the steering electronic control unit 4(ECU) processes and calculates the signals, the power-assisted motor 501 and the power-assisted pinion 506 rotate clockwise, the power-assisted gearwheel 507 is driven to rotate counterclockwise through gear engagement, and the power-assisted gearwheel 507 is also connected with the lead screw 511 into a whole, so that the lead screw 511 is driven to rotate counterclockwise, the nut 512 and the telescopic rod 502 are shortened inwards, and the wheels are driven to rotate to the right; as shown in fig. 5, when the driver steers the steering wheel 1 to turn the vehicle leftward, the input shaft 516 is driven to rotate counterclockwise, the torque angle sensor welded with the input shaft 516 sends the acquired steering force and steering angle signals to the steering electronic control unit 4(ECU), after the steering electronic control unit 4(ECU) processes and calculates the signals, the power-assisted motor 501 and the power-assisted pinion 506 rotate counterclockwise, the gear meshing drives the power-assisted gearwheel 507 to rotate clockwise, and the power-assisted gearwheel 507 is also connected with the lead screw 511, so that the lead screw 511 is driven to rotate clockwise, the nut 512 and the telescopic rod 502 extend outward, and the wheels are driven to rotate leftward.

The output torque can be changed by setting the gear ratio of the steering gear pair so as to adapt to the requirements of the steering torque of tires of vehicles with different loads, wherein the larger the gear ratio is, the larger the output torque is, and otherwise, the smaller the gear ratio is, the smaller the output torque is. The boosting gear pair is used for reducing speed and increasing torque, and the steering driving torque of the vehicle tire is basically provided by the motor through the boosting gear pair so as to reduce the steering burden of a driver.

As shown in fig. 8, the guide rods 514 are located inside the housing connecting tube 510, the axis of the guide rods 514 is parallel to the axis of the lead screw 511, two guide rods 514 are provided, and the included angle between the two guide rods 514 is 180 degrees. When the nut 512 is linearly reciprocated, the nut 512 is prevented from rotating in the circumferential direction by two guide rods 514. The nut 512 is provided with two oilless bushings 513, and each guide rod 514 passes through one oilless bushing 513. Two circular through holes are processed on the flange surface of the nut 512, each oilless shaft sleeve 513 is respectively installed in one circular hole through hole on the nut 512, the oilless shaft sleeve 513 is made of three layers of composite materials, and the two guide rods 514 respectively penetrate through the central holes of the two oilless shaft sleeves 513. The oilless bushing 513 is in small clearance fit with the guide rod 514, the two ends of the guide rod 514 are fixed, and when the screw receives a rotation moment, the two guide rods 514 restrain the moment in the circumferential direction of the nut 512. The outer circular surface of the guiding rod 514 is chrome-plated and hardened and then polished to ensure the rigidity and surface finish of the guiding rod 514, so that the guiding rod 514 has no bending deformation when keeping linear motion, and the friction coefficient of the oilless bushing 513 is low, thereby ensuring the smooth motion of the nut 512.

The electric power-assisted steering system of the large commercial vehicle with the structure has the following advantages:

1. the weight is light, and the application of the novel energy bus is more advantageous;

2. the whole vehicle is convenient to arrange, and the original vehicle steering gear arrangement scheme is adopted;

3. the product has high integration level and convenient installation, and does not have complex oil paths and oil path accessories which need to be assembled;

4. the steering is light, the noise is low, and the steering comfort and the active safety are high;

5. no hydraulic oil circuit exists, the oil leakage problem does not exist, and the environmental pollution is not caused;

6. different vehicle types can be matched quickly, and the best performance can be realized only by debugging the software setting of the steering electronic control unit 4;

7. the whole life cycle is maintenance-free, and fault diagnosis can be automatically and rapidly carried out;

8. the steering function requirements of auxiliary driving and automatic driving can be met;

9. the number of parts is small, and the cost is low;

10. the energy consumption is low, and the power-assisted motor 501 only works when the vehicle performs steering action;

11. the telescopic electric power steering assisting device 5 is of an integrated structure, the integration level is high, and the mechanical efficiency of the direct-acting telescopic structure is high.

The control method of the electric power steering system of the large-scale commercial vehicle comprises the following steps in a normal driving mode:

s11, after the vehicle is ignited, the steering electronic control unit 4 is electrified and prepares for work, and meanwhile, a vehicle running signal is obtained;

s12, when a driver rotates the steering wheel 1, the steering torque is transmitted to the telescopic electric power steering device through the steering column 2 and the steering transmission shaft 3, and the torque angle sensor collects the rotating torque and the rotating direction acting on the steering wheel 1 and the rotating angle signal of the steering wheel 1 and then sends the signals to the electronic steering control unit 4;

s13, the steering electronic control unit 4 processes the vehicle speed signal, the rotating torque and rotating direction signals on the steering wheel 1 and the rotating angle signal of the steering wheel 1, and outputs current and rotating direction signals to the power-assisted motor 501;

s14 and the input shaft 516 rotate, the power-assisted motor 501 rotates simultaneously, the telescopic rod 502 moves linearly, and the telescopic rod 502 drives the wheels to steer through the knuckle arm 6 and the tie rod 7.

As shown in fig. 2, in the normal driving mode, the steering electronic control unit 4(ECU) collects and calculates various signals to drive the power-assisted motor 501, and the power-assisted motor 501 drives the telescopic mechanism to transmit push-pull force to achieve tire steering.

In the above step S11, the acquired vehicle travel signal includes the vehicle ready and the travel speed signal.

In the step S14, the input shaft 516 drives the telescopic rod 502 of the telescopic electric power steering (PP-EPS) to perform a linear reciprocating motion; the power-assisted motor 501 drives the telescopic rod 502 on the telescopic electric power-assisted steering device (PP-EPS) to do linear reciprocating motion through the speed reducing mechanism, so that the telescopic rod 502 obtains superposition of steering force from the steering wheel 1 and motor power assistance; the telescopic rod 502 reciprocates, and drives wheels to steer left and right through the knuckle arm 6 and the steering tie rod 7; the steering force of the wheels is mostly provided by the assist motor 501, and the steering force of the steering wheel 1 is small and adjusted to a comfortable state for the driver.

The control method of the electric power steering system of the large-scale commercial vehicle comprises the following steps in an intelligent driving mode:

s21, after the vehicle is ignited, the steering electronic control unit 4 is electrified and prepares for work, and meanwhile, a vehicle running signal is obtained;

s22, the Vehicle Control Unit (VCU) sends a steering control signal to the steering electronic control unit 4;

s23, the steering electronic control unit 4 processes the steering control signal, and outputs a current and a rotation direction signal to the assist motor 501;

s24 and the power-assisted motor 501 operate, the telescopic rod 502 moves linearly, and the telescopic rod 502 drives the wheels to steer through the knuckle arm 6 and the tie rod 7.

As shown in fig. 3, in the intelligent driving mode, a Vehicle Control Unit (VCU) directly sends signals of a steering angle, an angular velocity, a direction and the like to a steering Electronic Control Unit (ECU) 4, the steering electronic control unit 4(ECU) processes and calculates the signals to drive a power-assisted motor 501, and the power-assisted motor 501 drives a telescopic mechanism to transmit a push-pull force to achieve tire steering.

In the above step S21, the acquired vehicle travel signal includes the vehicle ready and the travel speed signal.

In the above step S22, the steering control signal includes a steering angle, an angular velocity, and a steering direction signal.

In the step S23, the assist motor 501 drives the telescopic rod 502 of the telescopic electric power steering apparatus (PP-EPS) to perform a linear reciprocating motion through the speed reduction mechanism; the telescopic rod 502 reciprocates, and drives wheels to steer left and right through the knuckle arm 6 and the steering tie rod 7; the steering force of the wheels is mostly provided by the assist motor 501, and the steering force of the steering wheel 1 is small and adjusted to a comfortable state for the driver.

The invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above-described manner. Various insubstantial improvements are made by adopting the method conception and the technical proposal of the utility model; or without improvement, the above conception and technical solution of the present invention can be directly applied to other occasions, all within the protection scope of the present invention.

Claims

1. The utility model provides an electronic power assisted steering system of large-scale commercial car, includes steering drive shaft and knuckle arm, its characterized in that still includes telescopic electronic power assisted steering device, telescopic electronic power assisted steering device include with the input shaft of steering drive shaft connection, with the steering gear wheel of input shaft connection, with the steering pinion of steering gear wheel meshing, helping hand motor, the helping hand pinion of being connected with helping hand motor, with the helping hand pinion meshing and with steering pinion coaxial coupling's helping hand gear wheel, the ball screw mechanism of being connected with the helping hand gear wheel and be connected with the ball screw mechanism and with the outer tie rod of turning to the knuckle arm connection.

2. The electric power steering system of a large commercial vehicle of claim 1, wherein the telescopic electric power steering assistance device further comprises a housing assembly, the power motor is disposed on the housing assembly, and the ball screw mechanism, the steering bull gear, the steering pinion gear, the power pinion gear and the power bull gear are disposed inside the housing assembly.

3. The electric power steering system of the large commercial vehicle according to claim 1, wherein the ball screw mechanism comprises a screw connected with the steering gear wheel, a nut matched with the screw, a telescopic rod connected with the nut, and a guide rod guiding the nut, and the telescopic rod is connected with the outer steering pull rod through a joint bearing.

4. The electric power steering system of the large commercial vehicle according to claim 3, wherein the number of the guide rods is two, two oilless bushings are arranged on the nut, and each guide rod passes through one oilless bushing.