Pure electric steering system of heavy-duty commercial vehicle

Abstract

The invention relates to a pure electric steering system of a heavy commercial vehicle. The pure electric steering system comprises a steering wheel, a large-torque pure electric redundant steering gear and a steering pull rod. The steering wheel is connected with the steering pull rod through the large-torque pure electric redundant steering gear. The large-torque pure electric redundant steering gear comprises an angle transmission input shaft mechanism, a sensor module, a mechanical transmission mechanism, a speed reducing mechanism module and a motor power control module. The motor power control module decelerates and increases the torque output by a motor through the speed reducing mechanism module arranged at the bottom of the large-torque pure electric redundant steering gear, then is connected with a mechanical transmission mechanism and outputs the torque from a steering sector gear arm shaft assembly, and the sensor module is connected with the system controller and collects rotation angle and torque signals. And a current vehicle speed signal of the vehicle is read through a CAN, output torque is controlled through a motor power control module, and power-assisted output of the vehicle under different steering working conditions is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile steering systems, and in particular to a pure electric steering system for a heavy-duty commercial vehicle. Background Art

[0002] Because heavy-duty commercial vehicles have complex operating conditions and large steering shaft loads, the steering system currently used is often a hydraulic power steering system, which is a constant-flow hydraulic system. When the vehicle has no steering requirements, it also needs to consume a certain amount of energy to drive the entire hydraulic system to operate, especially under high-speed conditions. As the engine speed increases, the flow of the oil pump increases rapidly, resulting in more energy consumption. In addition, the hydraulic power steering system components require additional steering pumps, oil storage tanks and corresponding transmission pipelines, which are complex to arrange and are prone to pipeline aging and leakage after long-term use.

[0003] On the other hand, with the demand for autonomous driving of vehicles, a steering system with an electronic control unit is needed to realize automatic steering of the vehicle. Therefore, heavy-duty commercial vehicles urgently need an intelligent steering system that meets the development needs of vehicle energy saving, automation and system simplification. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and propose a pure electric steering system for heavy-duty commercial vehicles. The system solves the problem of large torque transmission of pure electric steering gears through large torque pure electric redundant steering gears, reduces the energy consumption of the steering system, simplifies the system structure, and can achieve different power output characteristics according to the driver's control requirements and vehicle status. At the same time, the redundant setting can meet the requirements of L3 and above autonomous driving intelligent control.

[0005] In order to solve the problems in the above background technology, the present invention is implemented by the following technical solutions:

[0006] A pure electric steering system for a heavy-duty commercial vehicle comprises a steering wheel, a large-torque pure electric redundant steering gear and a steering tie rod; the steering wheel is connected to the steering tie rod via the large-torque pure electric redundant steering gear: the large-torque pure electric redundant steering gear comprises an angular transmission input shaft mechanism, a sensor module, a mechanical transmission mechanism, a reduction mechanism module and a motor power control module; the motor power control module reduces the speed of the motor output torque and increases the torque through the reduction mechanism module arranged at the bottom of the large-torque pure electric redundant steering gear, and then connects with the mechanical transmission mechanism and outputs from the steering sector arm shaft assembly; the sensor module is connected to a system controller to collect angle and torque signals, and reads the current vehicle speed signal via CAN; the output torque is controlled via the motor power control module to achieve power output for different steering conditions of the vehicle.

[0007] Preferably, the steering wheel is connected to the telescopic shaft via a steering column, the telescopic shaft is connected to the high-torque pure electric redundant steering gear, and the high-torque pure electric redundant steering gear is connected to the steering tie rod via a steering rocker arm.

[0008] Preferably, the angular transmission input shaft mechanism is an integrated arrangement of an angular transmission mechanism and a steering gear input shaft, comprising an input spline shaft, an input bevel gear, an output bevel gear and an angular transmission input shaft mechanism housing, the input spline shaft is connected to the input bevel gear via a pin shaft or a spline, the input bevel gear is meshed with the output bevel gear, and the output bevel gear is connected to the sensor module.

[0009] Preferably, the sensor module includes an angle torque sensor and a torsion bar, and the angle torque sensor is a dual-channel redundant arrangement; the upper end of the torsion bar is connected to the output bevel gear via a spline sleeve, and the lower end of the torsion bar is connected to the mechanical transmission mechanism.

[0010] Preferably, the mechanical transmission mechanism includes a ball screw, balls, nuts, a fan tooth arm shaft assembly, a mechanism housing and a sleeve; the ball screw and the nut are both provided with the balls; cylindrical bosses are provided at the upper and lower ends of the nut, and the upper and lower ends of the nut respectively cooperate with the sleeves provided at the upper and lower ends of the mechanism housing to guide the upper and lower end movements of the nut, and the upper end of the ball screw is connected to the lower end of the torsion bar through a gear or a spline.

[0011] Preferably, the reduction mechanism module includes a reducer housing, an output shaft gear, an intermediate shaft output gear, an intermediate shaft input gear and an input shaft gear, the input shaft gear is connected to the motor power control module, and the output shaft gear is connected to the lower end of the ball screw.

[0012] Preferably, the motor power control module includes a motor assembly, a motor output shaft and a controller module. The motor assembly is a dual-winding motor. The controller module has dual MCUs, dual power supplies and dual CAN interfaces, and is redundantly configured. The controller module is connected to the vehicle power supply and the vehicle CAN respectively through the dual power supplies and dual CAN interfaces; the motor output shaft is connected to the intermediate shaft input gear.

[0013] Compared with the prior art, the present invention has the following beneficial technical effects:

[0014] The high-torque pure electric redundant steering gear solves the problem of high torque transmission of the pure electric steering gear, reduces the energy consumption of the steering system, simplifies the system structure, and can achieve different power output characteristics according to the driver's control requirements and vehicle status. At the same time, the redundant setting can meet the needs of L3 and above autonomous driving intelligent control. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a structural principle diagram of the present invention;

[0016] Figure 2 It is a schematic diagram of the structure of the present invention;

[0017] Notes on the attached drawings:

[0018] 1. Steering wheel; 2. Steering column; 3. Telescopic shaft; 4. Steering rocker arm; 5. High-torque pure electric redundant steering gear; 51. Angular transmission input shaft mechanism; 511. Input spline shaft; 512. Input bevel gear; 513. Output bevel gear; 514. Angular transmission input shaft mechanism housing; 52. Sensor module; 521. Torsion bar; 522. Angular torque sensor; 53. Mechanical transmission mechanism; 531. Ball screw; 532. Ball; 533. Nut; 534. Fan gear arm shaft assembly; 535. Mechanism housing; 536. Sliding sleeve; 54. Speed ​​reduction mechanism module; 541. Speed ​​reducer housing; 542. Output shaft gear; 543. Intermediate shaft output gear; 544. Intermediate shaft input gear; 545. Input shaft gear; 55. Motor power control module; 551. Motor assembly; 552. Motor output shaft; 553. Controller module; 6. Steering rod. DETAILED DESCRIPTION

[0019] like Figure 1-Figure 2 As shown, a pure electric steering system for a heavy-duty commercial vehicle includes a steering wheel 1, a large-torque pure electric redundant steering gear 5 and a steering rod 6; the steering wheel 1 is connected to the steering rod 6 through the large-torque pure electric redundant steering gear 5: the large-torque pure electric redundant steering gear 5 includes an angular transmission input shaft mechanism 51, a sensor module 52, a mechanical transmission mechanism 53, a reduction mechanism module 54 and a motor power control module 55. The motor power control module 55 reduces the speed of the motor output torque and increases the torque through the reduction mechanism module 54 arranged at the bottom of the large-torque pure electric redundant steering gear 5, and then connects with the mechanical transmission mechanism 53 and outputs it from the steering sector gear arm shaft assembly 534. The sensor module 52 is connected to the system controller to collect the angle and torque signals, and reads the current vehicle speed signal through the CAN. The output torque is controlled by the motor power control module 55 to achieve the power output of different steering conditions of the vehicle.

[0020] The steering wheel 1 is connected to the telescopic shaft 3 through the steering column 2 , the telescopic shaft 3 is connected to the large-torque pure electric redundant steering gear 5 , and the large-torque pure electric redundant steering gear 5 is connected to the steering tie rod 6 through the steering rocker arm 4 .

[0021] The angular transmission input shaft mechanism 51 is an integrated arrangement of an angular transmission mechanism and a steering gear input shaft, and includes an input spline shaft 511, an input bevel gear 512, an output bevel gear 513 and an angular transmission input shaft mechanism housing 514. The input spline shaft 511 is connected to the input bevel gear 512 via a pin shaft or a spline, the input bevel gear 512 is meshed with the output bevel gear 513, and the output bevel gear 513 is connected to the sensor module 52.

[0022] The sensor module 52 includes an angle torque sensor 522 and a torsion bar 521 . The angle torque sensor 522 is a dual-channel redundant setting. The upper end of the torsion bar 521 is connected to the output bevel gear 513 through a spline sleeve, and the lower end of the torsion bar 521 is connected to the mechanical transmission mechanism 53 .

[0023] The mechanical transmission mechanism 53 includes a ball screw 531, a ball 532, a nut 533, a fan gear arm shaft assembly 534, a mechanism housing 535 and a sleeve 536; the ball screw 531 and the nut 533 are both provided with a ball 532; the upper and lower ends of the nut 533 are provided with cylindrical bosses, and the upper and lower ends of the nut 533 are respectively matched with the sleeves 536 provided at the upper and lower ends of the mechanism housing 535 to guide the upper and lower ends of the nut 533. The upper end of the ball screw 531 is connected to the lower end of the torsion bar 521 through a gear or a spline.

[0024] The speed reduction mechanism module 54 includes a speed reducer housing 541, an output shaft gear 542, an intermediate shaft output gear 543, an intermediate shaft input gear 544 and an input shaft gear 545. The input shaft gear 545 is connected to the motor power control module 55, and the output shaft gear 542 is connected to the lower end of the ball screw 531.

[0025] The motor power control module 55 includes a motor assembly 551, a motor output shaft 552 and a controller module 553. The motor assembly 551 is a dual-winding motor. The controller module 553 has dual MCUs, dual power supplies and dual CAN interfaces, and is redundantly configured. The controller module 553 is connected to the vehicle power supply and the vehicle CAN through the dual power supplies and dual CAN interfaces respectively; the motor output shaft 552 is connected to the intermediate shaft input gear 544.

[0026] When the vehicle is operated by a driver, the driver first inputs a certain angle and torque through the steering wheel 1. The torque causes the input spline shaft 511 to rotate, and through the meshing of the input bevel gear 512 and the output bevel gear 513, the transmission reversal is achieved under the premise of ensuring constant speed; the output bevel gear 513 is connected to the upper end of the torsion bar 521 through a spline sleeve, and the lower end of the torsion bar 521 is connected to the ball screw 531 through a gear or a spline. When the torque drives the torsion bar 521 to rotate, the upper end of the torsion bar 521 deflects a certain angle relative to the ball screw 531. In this way, the angle torque sensor 522 collects the driver's steering angle and torque information, which will be transmitted to the controller module 553. At this time, combined with the vehicle CAN reading of vehicle speed, engine speed, yaw angular velocity and other message information, the target current is obtained through the power assist characteristic strategy preset in the motor power control module 55, and the output torque of the motor assembly 551 is controlled by the current to achieve power assist under different working conditions.

[0027] The output torque is transmitted to the speed reduction mechanism module 54 through the motor output shaft 552. The torque is respectively transmitted through the input shaft gear 545 and the intermediate shaft input gear 544 to achieve the first stage of speed reduction and torque increase, and then through the intermediate shaft output gear 543 and the output shaft gear 542 to achieve the second stage of speed reduction and torque increase. At this time, the output torque can generally reach 300N.m to 400N.m. All teeth of the gears of the speed reduction mechanism module 54 are made of lightweight and high-strength materials to reduce the rotational inertia of the transmission mechanism and improve the response of the system.

[0028] Then the output shaft gear 542 transmits the torque to the mechanical transmission mechanism 53, and the ball screw 531 rotates under the torque. The ball 532 arranged between the ball screw 531 and the nut 533 converts the rotational motion of the screw into the linear motion of the nut, thereby realizing the first-stage transmission of the ball screw 531 and the nut 533. On the one hand, the ball screw 531 structure adopts a larger number of steel balls 532 to share the transmission of the large torque, so that the force of each ball 532 is improved and the working life is extended. On the other hand, On the one hand, the upper and lower ends of the nut 533 are made into cylindrical bosses, and cooperate with the upper and lower sleeves 536 fixedly connected to the mechanism housing 535 to guide the upper and lower end movements of the nut 533 at the same time, which can ensure the precise guidance of the nut 533 and alleviate the wear of the ball 532 caused by the radial force of the screw. In addition, through the material matching of the sleeve 536 and the boss of the nut 533, the resistance of the nut 533 can be effectively improved to ensure a good lubrication effect, thereby effectively solving the problem that the ball screw 531 is difficult to withstand large torque transmission.

[0029] Finally, the up and down linear motion of the nut 533 drives the fan gear arm shaft assembly 534 to rotate, realizing the second stage transmission of the mechanical transmission mechanism 53, and drives the steering rocker arm 4 and the steering tie rod 6 to realize the steering of the steering wheel.

Claims

1. A pure electric steering system for a heavy commercial vehicle, characterized in that: The invention comprises a steering wheel (1), a large-torque pure electric redundant steering gear (5) and a steering tie rod (6); the steering wheel (1) is connected to the steering tie rod (6) via the large-torque pure electric redundant steering gear (5); the large-torque pure electric redundant steering gear (5) comprises an angular transmission input shaft mechanism (51), a sensor module (52), a mechanical transmission mechanism (53), a speed reduction mechanism module (54) and a motor power control module (55); the motor power control module (55) reduces the speed of the motor output torque and increases the torque through the speed reduction mechanism module (54) arranged at the bottom of the large-torque pure electric redundant steering gear (5), and then connects with the mechanical transmission mechanism (53) and outputs from the steering sector gear arm shaft assembly (534); the sensor module (52) is connected to the system controller to collect the angle and torque signals, and read the current vehicle speed signal through the CAN; the output torque is controlled through the motor power control module (55) to realize the power output of the vehicle under different steering conditions.

2. The pure electric steering system for heavy commercial vehicles according to claim 1, characterized in that: The steering wheel (1) is connected to the telescopic shaft (3) via a steering column (2); the telescopic shaft (3) is connected to the high-torque pure electric redundant steering gear (5); and the high-torque pure electric redundant steering gear (5) is connected to the steering tie rod (6) via a steering rocker arm (4).

3. The pure electric steering system for heavy commercial vehicles according to claim 1, characterized in that: The angular transmission input shaft mechanism (51) is an integrated arrangement of an angular transmission mechanism and a steering gear input shaft, comprising an input spline shaft (511), an input bevel gear (512), an output bevel gear (513) and an angular transmission input shaft mechanism housing (514); the input spline shaft (511) is connected to the input bevel gear (512) via a pin shaft or a spline; the input bevel gear (512) and the output bevel gear (513) are meshed; and the output bevel gear (513) is connected to the sensor module (52).

4. The pure electric steering system for heavy commercial vehicles according to claim 1, characterized in that: The sensor module (52) comprises an angle torque sensor (522) and a torsion bar (521), wherein the angle torque sensor (522) is a dual-channel redundant arrangement; the upper end of the torsion bar (521) is connected to the output bevel gear (513) via a spline sleeve, and the lower end of the torsion bar (521) is connected to the mechanical transmission mechanism (53).

5. The pure electric steering system for heavy commercial vehicles according to claim 1, characterized in that: The mechanical transmission mechanism (53) comprises a ball screw (531), a ball (532), a nut (533), a fan gear arm shaft assembly (534), a mechanism housing (535) and a sliding sleeve (536); the ball screw (531) and the nut (533) are both provided with the ball (532); the upper and lower ends of the nut (533) are provided with cylindrical bosses, the upper and lower ends of the nut (533) respectively cooperate with the sliding sleeves (536) provided at the upper and lower ends of the mechanism housing (535) to guide the upper and lower ends of the nut (533); the upper end of the ball screw (531) is connected to the lower end of the torsion bar (521) through a gear or a spline.

6. The pure electric power steering system for heavy commercial vehicles according to claim 1, characterized in that: The speed reduction mechanism module (54) comprises a speed reducer housing (541), an output shaft gear (542), an intermediate shaft output gear (543), an intermediate shaft input gear (544) and an input shaft gear (545); the input shaft gear (545) is connected to the motor power control module (55); and the output shaft gear (542) is connected to the lower end of the ball screw (531).

7. The pure electric steering system for heavy commercial vehicles according to claim 5, characterized in that: The motor power control module (55) comprises a motor assembly (551), a motor output shaft (552) and a controller module (553); the motor assembly (551) is a dual-winding motor; the controller module (553) is a dual MCU, dual power supply and dual CAN interface, and is redundantly configured; the controller module (553) is connected to the vehicle power supply and the vehicle CAN via the dual power supply and the dual CAN interface respectively; the motor output shaft (552) is connected to the intermediate shaft input gear (544).

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