CN-122003355-A - Steer-by-wire steering assembly

Abstract

A steer-by-wire steering assembly includes a motor assembly having at least one motor mounted in a housing, and a screw actuator configured to engage a threaded portion of a steering shaft and move the steering shaft along a longitudinal axis. It also includes a rotor-carrying sleeve operatively coupled between the at least one motor and the screw actuator configured to rotate about a longitudinal axis, and a sensor assembly including a sensor portion and a target portion configured to detect relative movement of the steering shaft with respect to the housing. One of the sensor portion and the target portion is mounted in a sensor housing that is fixed relative to the steering shaft. The housing includes a sensor channel for receiving the sensor housing and limiting movement of the sensor housing and the steering shaft in a direction parallel to the longitudinal axis.

Inventors

• C. MATTHEWS
• D Rojas
• T. Tarkane
• K. Kidd to Ford
• P. NELSON
• T.LI

Assignees

• 智控底盘系统科技有限公司

Dates

Publication Date

20260508

Application Date

20241004

Priority Date

20231009

Claims (17)

1. 1. A steer-by-wire steering assembly (100), comprising: A housing (102); A motor assembly (206), the motor assembly (206) comprising at least one motor (208) mounted in the housing (102); -a screw actuator (232), the screw actuator (232) being configured to engage with a threaded portion (234) of a steering shaft (118) and to move the steering shaft (118) along a longitudinal axis (104) upon rotation of the screw actuator (232); a rotor-carrying sleeve (216), the rotor-carrying sleeve (216) being operably coupled between the at least one motor (208) and the screw actuator (232) and configured to rotate about the longitudinal axis (104); A sensor assembly (238), the sensor assembly (238) comprising a sensor portion (244) and a target portion (246), the sensor portion (244) and the target portion (246) configured to detect relative movement of the steering shaft (118) with respect to the housing (102); wherein one of the sensor portion (244) and the target portion (246) is mounted in a sensor housing (316) that is fixed relative to the steering shaft (118), and The housing (102) includes a sensor channel (302), the sensor channel (302) configured to receive the sensor housing (316) and limit movement of the sensor housing (316) and the steering shaft (118) in a direction parallel to the longitudinal axis (104).
2. 2. The steer-by-wire steering assembly (100) according to claim 1, wherein the sensor assembly (238) is a linear displacement sensor assembly (238).
3. 3. The steer-by-wire steering assembly (100) of claim 1 or 2, wherein the sensor housing (316) is configured to slide within the sensor channel (302).
4. 4. A steer-by-wire steering assembly (100) according to any of claims 1-3, wherein the sensor channel (302) is located within a housing sleeve portion (300) of the housing (102).
5. 5. The steer-by-wire steering assembly (100) of claim 4, further comprising a mounting assembly (306), the mounting assembly (306) being secured to the housing sleeve portion (300) and including at least one elongated rail (308) defining the sensor channel (302).
6. 6. The steer-by-wire steering assembly (100) of claim 5, wherein the mounting assembly (306) further comprises a fastener (310), the fastener (310) configured to clamp the at least one elongated rail (308) to an inner surface of the housing sleeve portion (300).
7. 7. The steer-by-wire steering assembly (100) according to any one of claims 1-6, wherein the sensor housing (316) comprises a shaft engagement sleeve (320), the shaft engagement sleeve (320) being configured to be mounted around the steering shaft (118).
8. 8. The steer-by-wire steering assembly (100) of claim 7, wherein the shaft engagement sleeve (320) includes a central bore (322), the central bore (322) configured to receive the steering shaft (118).
9. 9. The steer-by-wire steering assembly (100) according to any one of claims 1-8, wherein the sensor housing (316) comprises a first housing engagement surface (318) and a second housing engagement surface (326), the first housing engagement surface (318) and the second housing engagement surface (326) being configured to engage with a first channel engagement surface (304) and a second channel engagement surface (324), respectively, of the sensor channel (302).
10. 10. The steer-by-wire steering assembly (100) of claim 9, wherein the sensor channel (302) includes the first channel engagement surface (304) and the second channel engagement surface (324), the first channel engagement surface (304) configured to engage the first housing engagement surface (318) when the screw actuator (232) rotates in a first direction, the second channel engagement surface (324) configured to engage the second housing engagement surface (326) when the screw actuator (232) rotates in a second direction.
11. 11. The steer-by-wire steering assembly (100) according to any one of claims 1 to 10, wherein the sensor housing (316) is mounted on the steering shaft (118) using a set screw, a press fit, or a weld.
12. 12. The steer-by-wire steering assembly (100) according to any one of claims 1 to 11, further comprising a second sensor assembly (500), the second sensor assembly (500) comprising a second sensor portion (244 b) and a second target portion (246 a), the second sensor portion (244 b) and the second target portion (246 a) configured to detect relative movement of the steering shaft (118) with respect to the housing (102).
13. 13. The steer-by-wire steering assembly (100) according to claim 12, wherein the second sensor assembly (500) is a linear displacement sensor assembly (238).
14. 14. The steer-by-wire steering assembly (100) according to claim 12 or 13, wherein one of the second sensor portion (244 b) and the second target portion (246 b) is mounted in a second sensor housing (502) that is fixed relative to the steering shaft (118).
15. 15. The steer-by-wire steering assembly (100) of claim 14, wherein the second sensor housing (502) is configured to slide within a second sensor channel (302) in the housing (102).
16. 16. The steer-by-wire steering assembly (100) according to any one of claims 12 to 15, wherein the first sensor assembly (238) and the second sensor assembly (500) are mounted at different locations on the steering shaft (118).
17. 17. The steer-by-wire steering assembly (100) according to any one of claims 1-16, wherein the motor assembly (206) comprises a first motor (208) and a second motor (210), and the rotor carrying sleeve (216) is operably coupled between the first motor (208), the second motor (210), and the screw actuator (232).

Description

Steer-by-wire steering assembly Technical Field The present technology relates to the field of automotive engineering, and in particular to steering systems for vehicles. In particular, it focuses on steer-by-wire systems, which are electronic systems that utilize electronic components and sensors instead of the traditional mechanical linkage between the steering wheel and the vehicle wheels. Background The automotive industry is continually developing techniques to assist users in performing various driving operations in a vehicle, including steering. Power steering systems have been introduced to assist drivers and even control steering for them. With the advancement of automobile technology, the realization of full automation of vehicles and the elimination of user input demands are on the growing trend. One key aspect of autonomous vehicle control is automatic steering, which typically requires a steer-by-wire steering system that can be controlled by control signals from a vehicle control unit. Steer-by-wire systems do not necessarily require mechanical linkage between a user input, such as a steering wheel, and a steering linkage, such as a rack and pinion. In some steer-by-wire embodiments, no user input is required because the system is fully controlled by the autonomous vehicle control unit. However, without user input, the vehicle system of an autonomous vehicle needs to be robust enough to make the vehicle reliable. This may mean that steer-by-wire systems have multiple redundancies to meet industry safety standards, such as class C or class D of the Automobile Safety Integrity Level (ASIL) of ISO 26262. EP 3 819 190 shows one such steer-by-wire system, which discloses a steer-by-wire actuation system having two steering motors and two electronic control units controlling the steering motors to control the rotation of the two steering motors. The two steering motors are connected to ball screws that interact with mating ball screw nuts mounted on the shaft. A problem with current steer-by-wire systems is that the steering shaft may rotate with the ball screw, which means that the steering shaft may not always be in linear motion. The steering shaft must be prevented from rotating to ensure proper linear motion and steering control. Furthermore, the steering assembly must have a compact form in order to be easily integrated into a new vehicle form factor that may have limited space for components. Another problem with existing steer-by-wire systems for autonomous vehicles is that they are prototype systems and are bulky. This means that they are not suitable for use in an industrial manufacturing process for assembling an autonomous vehicle with a small form factor, since the original steer-by-wire system takes up too much space. Additionally, existing steer-by-wire systems typically involve complex mechanical components, such as ball screws and mating ball screw nuts, which can be bulky and render the system unsuitable for use in an industrial manufacturing process. Furthermore, the layout and packaging of existing steer-by-wire systems may not be optimized for space efficiency, resulting in a large overall volume and making it difficult to integrate the system into an autonomous vehicle with a small form factor. A steer-by-wire steering assembly generally includes two motors, each having a stator and a common rotor. The rotor is coupled to a ball screw (screw actuator) that engages a threaded portion of the steering shaft. When one or both motors are rotated, the steering shaft moves linearly along the steering shaft axis. However, a problem with such a system is that alignment of the electrical connections of the motor may be difficult. Additionally, long wires between the motor and the controller may receive and generate interference signals, which may negatively impact the performance and reliability of the system. Prior art steer-by-wire systems, such as the system disclosed in EP 3 819 190, use wires to connect the motor to the controller. This can lead to problems with electrical interference and vibration damage to the wires. Furthermore, alignment and assembly of electrical connections can be challenging and time consuming, resulting in difficulties in the installation and maintenance process. In the known system, the position of the steering shaft is detectable by means of a linear sensor. A problem with existing linear sensors is that the length of the linear sensor is relatively long with respect to the actuator. This is because the linear sensor must have the length of the full steering shaft travel (from fully locked wheel to fully locked wheel). This increases the size of the actuator, as the linear sensor needs to be mounted in a protective housing. To ensure the reliability and safety of steer-by-wire systems, redundancy is often added to the design. One common way to achieve redundancy is to use multiple motors to actuate the steering actuators. In such systems, if one motor fai