A steer-by-wire steering assembly

Abstract

A steer-by-wire assembly includes a motor assembly with at least one motor mounted in a housing, and a screw actuator configured to engage with a threaded portion of a steering shaft and move the steering shaft along a longitudinal axis. It also includes a rotor carrier sleeve operatively coupled between the at least one motor and the screw actuator, configured to rotate about the longitudinal axis, and a sensor assembly comprising 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 are mounted in a sensor housing fixed with respect to the steering shaft. The housing comprises a sensor channel for receiving the sensor housing and constrain the movement of the sensor housing and the steering shaft in a direction parallel to the longitudinal axis.

Description

[0001] A steer-by-wire steering assembly

[0002] Field

[0003] The technology relates to the field of automotive engineering, specifically to steering systems for vehicles. In particular, it focuses on steer-by-wire systems, which are electronic systems that replace traditional mechanical linkages between the steering wheel and the vehicle's wheels with electronic components and sensors.

[0004] The automotive industry has been continuously developing technology to assist users with various driving operations in vehicles, including steering. Powered steering systems have been introduced to assist drivers or even control the steering for them. As automotive technology advances, there is a growing trend towards fully automating vehicles, eliminating the need for user input. One critical aspect of autonomous vehicular control is autonomous steering, which typically requires steer-by-wire steering systems that can be controlled by control signals from a vehicle control unit.

[0005] A steer-by-wire system does not necessarily require a mechanical linkage between a user input, such as a steering wheel, and the steering linkage, such as a rack and pinion steering assembly. In some steer-by-wire implementations, no user input is needed because the system is fully controlled by an autonomous vehicle control unit. However, in the absence of user input, the vehicular systems of the autonomous vehicle need to be robust for the vehicle to be reliable. This may mean that the steer- by-wire systems have multiple redundancies to meet industrial safety standards, such as Automotive Safety Integrity Level (ASIL) C or D ISO 26262.

[0006] One such steer-by-wire system is shown in EP 3 819 190, which discloses a steer-by- wire actuation system with two steering motors and two electrical control units controlling the steering motors for controlling the rotation of the two steering motors. The two steering motors are connected to a ball screw, which interacts with a cooperating ball screw nut mounted on a shaft. A problem with the current steer-by-wire systems is that the steering shaft can rotate together with the ball screw, which means that the steering shaft may not always move linearly. The steering shaft must be prevented from rotating to ensure proper linear movement and steering control. Furthermore, the steering assembly must have a compact form to be easily incorporated into new vehicle form factors, which may have limited space for components.

[0007] Another problem with existing steer-by-wire systems for autonomous vehicles is that they are prototypes and have a large volume. This means that they are unsuitable for use in an industrialised manufacturing process for assembling autonomous vehicles with small form factors because the prototype steer-by-wire systems take up too much space. Additionally, existing steer-by-wire systems often involve complex mechanical components, such as ball screws and cooperating ball screw nuts, which can be bulky and contribute to the large volume of the system, making it unsuitable for industrialised manufacturing processes. Furthermore, the layout and packaging of existing steer-by- wire systems may not be optimised for space efficiency, resulting in a larger overall volume and making it difficult to integrate the system into autonomous vehicles with small form factors.

[0008] A steer-by-wire assembly typically comprises two motors, each with a stator and a common rotor. The rotor is coupled to a ball screw (screw actuator) which engages a threaded portion of the steering shaft. The steering shaft moves linearly along the steering shaft axis when one or both of the motors rotate. However, a problem with such systems is that the alignment of the electrical connections to the motors can be difficult. Additionally, long wires between the motors and the controller can receive and generate interference signals, which can negatively impact the performance and reliability of the system.

[0009] The prior art steer-by-wire systems, such as the one disclosed in EP 3 819 190, use wires to connect the motors to the controller. This can cause issues with electrical interference and vibrations damaging the wires. Furthermore, the alignment and assembly of the electrical connections can be challenging and time-consuming, leading to difficulties in the installation and maintenance process. In known systems the position of the steering shaft may be detected with a linear sensor. A problem with existing linear sensors is that the length of the linear sensor is quite long with respect to the actuator. This is because the linear sensor has to be the length of the full stroke (full wheel lock to full wheel lock) of the steering shaft. This increases the size of the actuator because the linear sensor needs to be mounted in protective housing.

[0010] In order to ensure the reliability and safety of steer-by-wire systems, redundancy is often incorporated into the design. One common approach to achieving redundancy is to use multiple motors to actuate the steering actuator. In such systems, if one motor fails, the other motor can continue to provide steering functionality, thereby maintaining the overall functionality of the steering system.

[0011] However, there are several problems associated with the prior art steer-by-wire systems that utilise multiple motors for redundancy. One issue is the potential for failure in the motor windings of the motors used in the steering assembly. Motor winding failures can occur due to various reasons, such as excessive motor winding temperature, manufacturing defects, or other factors that can lead to the degradation of the motor windings. If a failure occurs in the motor windings of one motor, the redundancy provided by the second motor may be compromised, potentially leading to a loss of steering functionality.

[0012] Another problem with prior art steer-by-wire systems is the possibility of multiple failures occurring in the motor windings of both motors. In such cases, the redundancy provided by the multiple motors may not be sufficient to maintain the functionality of the steering system, resulting in a complete loss of steering control.

[0013] Furthermore, the current designs with two motors may not provide enough redundancy to ensure the continuous functionality of the steer-by-wire steering assembly in all situations. This can pose a significant safety risk, as a loss of steering control can lead to accidents and other dangerous situations.

[0014] Summary According to a first aspect of the disclosure, a steer-by-wire steering assembly is provided, which includes a housing, a motor assembly with at least one motor mounted in the housing, a screw actuator configured to engage with a threaded portion of a steering shaft and move the steering shaft along a longitudinal axis when the screw actuator rotates, a rotor carrier sleeve operatively coupled between the at least one motor and the screw actuator and configured to rotate about the longitudinal axis, and a sensor assembly comprising 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 are mounted in a sensor housing fixed with respect to the steering shaft, and the housing comprises a sensor channel configured to receive the sensor housing and constrain the movement of the sensor housing and the steering shaft in a direction parallel to the longitudinal axis. This aspect provides the advantage of ensuring proper linear movement of the steering shaft and preventing its rotation.

[0015] Optionally in some examples, the sensor assembly is a linear displacement sensor assembly, providing the advantage of accurately measuring the linear displacement of the steering shaft.

[0016] Optionally in some examples, the sensor housing is configured to slide within the sensor channel, allowing for smooth movement of the sensor housing and steering shaft along the longitudinal axis.

[0017] Optionally in some examples, the sensor channel is located within a housing sleeve portion of the housing, providing additional protection to the sensor assembly.

[0018] Optionally in some examples, the steering assembly further comprises a mounting assembly fixed to the housing sleeve portion and comprising at least one elongate rail defining the sensor channel, providing a secure and stable mounting for the sensor assembly. Optionally in some examples, the mounting assembly further comprises fasteners configured to clamp the at least one elongate rail to an inner surface of the housing sleeve portion, ensuring a secure attachment of the mounting assembly to the housing.

[0019] Optionally in some examples, the sensor housing comprises a shaft engagement sleeve configured to mount around the steering shaft, providing a secure connection between the sensor housing and the steering shaft.

[0020] Optionally in some examples, the shaft engagement sleeve comprises a central bore configured to receive the steering shaft, allowing for easy installation and removal of the steering shaft.

[0021] Optionally in some examples, the sensor housing comprises a first housing engagement surface and a second housing engagement surface configured to engage respectively with first channel and second channel engagement surfaces of the sensor channel, ensuring proper engagement between the sensor housing and the sensor channel.

[0022] Optionally in some examples, the sensor channel comprises a first channel engagement surface configured to engage the first housing engagement surface when the screw actuator rotates in a first direction, and a second channel engagement surface configured to engage the second housing engagement surface when the screw actuator rotates in a second direction, providing a secure engagement between the sensor housing and the sensor channel during both directions of rotation.

[0023] Optionally in some examples, the sensor housing is mounted on the steering shaft using a set screw, press fit, or welding, providing a secure and reliable connection between the sensor housing and the steering shaft.

[0024] Optionally the steer-by-wire steering assembly further comprises a second sensor assembly comprising a second sensor portion and a second target portion configured to detect relative movement of the steering shaft with respect to the housing, providing redundancy and increased reliability in the detection of the steering shaft's movement. Optionally in some examples, the second sensor assembly is a linear displacement sensor assembly, providing accurate measurement of the linear displacement of the steering shaft.

[0025] Optionally in some examples, one of the second sensor portion and the second target portion are mounted in a second sensor housing fixed with respect to the steering shaft, ensuring a secure connection between the second sensor assembly and the steering shaft.

[0026] Optionally in some examples, the second sensor housing is configured to slide within a second sensor channel in the housing, allowing for smooth movement of the second sensor housing and steering shaft along the longitudinal axis.

[0027] Optionally in some examples, the first and second sensor assemblies are mounted at different positions on the steering shaft, providing increased accuracy and reliability in the detection of the steering shaft's movement.

[0028] Optionally the motor assembly comprises a first motor and a second motor, and the rotor carrier sleeve is operatively coupled between the first motor, the second motor, and the screw actuator, providing increased power and torque for the steering assembly.

[0029] Brief Description of the Drawings

[0030] Examples are described in more detail below with reference to the appended drawings. Figure 1 is a cross-sectional side view of a steer-by-wire steering assembly according to an example;

[0031] Figure 2 is a close-up cross-sectional view of the steer-by-wire steering assembly according to an example;

[0032] Figure 3 is a detailed cross-sectional view of the steer-by-wire steering assembly according to an example;

[0033] Figure 4 is a cross-sectional view of the sensor housing and sensor channel in engagement according to an example; Figure 5 is a perspective view of the sensor housing and sensor channel in engagement according to an example;

[0034] Figure 6 is a perspective view of the sensor housing mounted on the steering shaft without the housing according to an example;

[0035] Figure 7 is a schematic diagram of the steer-by-wire steering assembly including the controller and sensor assemblies according to an example

[0036] Figure 8 is another close-up cross-sectional view of a steer-by-wire assembly according to an example;

[0037] Figure 9 is a perspective cut-away view of a steer-by-wire assembly according to an example;

[0038] Figure 10 is a perspective view of some components of a steer-by-wire assembly according to an example;

[0039] Figure 11 is a perspective view of a rotor carrier sleeve of a steer-by-wire assembly according to an example;

[0040] Figure 12 is a detailed cross-sectional view of the steer-by-wire steering assembly according to an example;

[0041] Figure 13 is a cross-sectional view of a motor assembly connector according to an example;

[0042] Figure 14 is a schematic view of a linear displacement sensor assembly according to an example;

[0043] Figure 15a is a schematic view of another linear displacement sensor assembly according to an example;

[0044] Figure 15b is a schematic cross-sectional view of the linear displacement sensor assembly shown in Figure 15b;

[0045] Figure 16 is a schematic representation of the first and second plurality of motor windings and their arrangement according to an example; and

[0046] Figure 17 is a flowchart depicting the method of operating the steer-by-wire steering assembly.

[0047] Detailed Description The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practise the disclosure.

[0048] Figure 1 shows a cross-sectional side view of a steer-by-wire steering assembly 100 according to an example. The steer-by-wire steering assembly 100 includes a housing 102 and a motor assembly 206 comprising at least one motor 208 mounted in the housing 102. The steer-by-wire steering assembly 100 also includes a screw actuator 232 configured to engage with a threaded portion 234 of a steering shaft 118 and move the steering shaft 118 along a longitudinal axis 104 of the steer-by-wire steering assembly 100 when the screw actuator 232 rotates. The steering assembly 100 also includes a rotational sensor assembly 236 comprising a rotary sensor target 242 and a rotary sensor 240 configured to detect relative rotational movement of the rotary sensor target 242. The steering assembly 100 includes a housing 102 that encloses various components of the steering assembly 100. The housing 102 is designed to protect the internal components from external elements and provide structural support.

[0049] Figure 2 is a close-up cross-sectional view of the steer-by-wire steering assembly 100 according to an example. Figure 2 is a close-up cross-sectional view of the dotted boxed labelled A as indicated in Figure 1. The steer-by-wire steering assembly 100 includes a rotor carrier sleeve 216 operatively coupled between the at least one motor 208 and the screw actuator 232 and configured to rotate about the longitudinal axis 104. The steer-by-wire steering assembly 100 also includes a sensor assembly 238 comprising a sensor portion 244 and a linear displacement target portion 246 configured to detect relative movement of the steering shaft 118 with respect to the housing 102. The steering assembly 100 features a rotor carrier sleeve 216 with an end cup formation 4300 configured to receive the screw actuator 232. The end cup formation 4300 includes a sleeve inner threaded portion 4302 configured to engage with the rotary sensor target 242. The motor assembly 206 comprises at least one motor 208 mounted in the housing 102 and is responsible for rotating the screw actuator 232. The threaded portion 234 has a threaded portion length 1300. Figure 3 is a detailed cross-sectional view of the steer-by-wire steering assembly 100 according to an example. Figure 3 is a close-up cross-sectional view of the dotted boxed labelled B1 as indicated in Figure 1. The housing 102 comprises a sensor channel 302 configured to receive a sensor housing 316 and constrain the movement of the sensor housing 316 and the steering shaft 118 in a direction parallel to the longitudinal axis 104.

[0050] Figure 4 is a cross-sectional view of the sensor housing 316 and sensor channel 302 in engagement according to an example. Figure 4 is a cross-sectional view along the axis labelled C as indicated in Figures 1 and 3. The sensor housing 316 is configured to slide within the sensor channel 302 and includes a first housing engagement surface 318 and a second housing engagement surface 326 configured to engage respectively with first channel and second channel engagement surfaces 304, 324 of the sensor channel 302.

[0051] Figure 5 is a perspective view of the sensor housing 316 and sensor channel 302 in engagement according to an example. The sensor channel 302 is located within a housing sleeve portion 300 of the housing 102 and includes a mounting assembly 306 fixed to the housing sleeve portion 300 and comprising at least one elongate rail 308 defining the sensor channel 302.

[0052] Figure 6 is a perspective view of the sensor housing 316 mounted on the steering shaft 118 according to an example. The housing 102 is not shown in Figure 6 for the purposes of clarity. The sensor housing 316 comprises a shaft engagement sleeve 320 configured to mount around the steering shaft 118 and includes a central bore 322 configured to receive the steering shaft 118.

[0053] Figure 7 is a schematic diagram of the steer-by-wire steering assembly 100 including the controller and sensor assemblies according to an example. The assembly includes a first motor 208 and a second motor 210, and the rotor carrier sleeve 216 is operatively coupled between the first motor 208, the second motor 210, and the screw actuator 232. The assembly also includes a first sensor assembly 238, e.g. a linear displacement sensor assembly 238 and a second sensor assembly 500 , e.g. a linear displacement sensor assembly 500 mounted at different positions on the steering shaft 118. Figure 7 also shows a rotational sensor assembly 236 with a rotary sensor 240 selected from one or more of an optical rotary sensor, a magnetic rotary sensor, a capacitive rotary sensor, an inductive rotary sensor, a Hall effect rotary sensor, and a resolver. The steering assembly 100 also includes a rotational sensor assembly 236 configured to detect relative rotational movement of the steering shaft 118 with respect to the housing 102. The rotational sensor assembly 236 comprises a rotary sensor 240 and a rotary sensor target 242.

[0054] Figure 8 is another close-up cross-sectional view of the steering assembly 100 according to an example. Figure 8 is a close-up cross-sectional view of the dotted boxed labelled B2 as indicated in Figure 2. In this view, the rotary sensor target 242 comprises a target threaded portion 4316 configured to engage with the sleeve inner threaded portion 4302 of the rotor carrier sleeve 216.

[0055] Figure 9 is a perspective cut-away view of the steering assembly 100 according to an example. The steering assembly 100 includes a motor assembly 206 with a first motor 208 and a second motor 210. The steering assembly 100 also features a screw actuator 232 mounted in the same radial plane 4318 as an outer bearing 4314 and the end cup formation 4300.

[0056] Figure 10 is a perspective view of some components of the steering assembly 100 according to an example. The components include a rotor carrier sleeve 216 with a key slot 4306 configured to receive a key element 4312, which is configured to engage an internal surface of an outer bearing 4314 and align and maintain the position of the rotor carrier sleeve 216 with respect to the outer bearing 4314.

[0057] Figure 11 is a perspective view of a rotor carrier sleeve 216 of the steering assembly 100 according to an example. The sleeve features an end cup formation 4300 with a cup shoulder portion 4308 configured to abut and position the outer bearing 4314. The sleeve also includes a sleeve outer threaded portion 4304 configured to engage with an outer locking nut 4310. Figure 12 is a detailed cross-sectional view of the steer-by-wire steering assembly 100 according to an example. Figure 12 is a close-up cross-sectional view of the dotted boxed labelled B3 as indicated in Figure 2. The steering assembly 100 includes a rotor carrier sleeve 216 operatively coupled between the first rotor 214 and the second rotor 220 and the screw actuator 232. A motor assembly connector 2300 is configured to provide mechanical connection and electrical connection to both the first motor 208 and the second motor 210. In some examples, the motor assembly connector 2300 is configured to provide mechanical connection and electrical connection to both the first stator 212 and the second stator 218.

[0058] Figure 13 is a cross-sectional view of a motor assembly connector 2300 according to an example. The motor assembly connector 2300 comprises a connector body 2302 mounted between the first stator 212 and the second stator 218. The connector body 2302 is made of metal or rigid plastic, ensuring high strength and durability. The motor assembly connector 2300 also includes at least one assembly window 2304 exposing one or more stator terminals from the first stator 212 or the second stator 218 for soldering or welding.

[0059] The motor assembly connector 2300 comprises electrical connection tracks 2320 configured to electrically connect each terminal of the first stator 212 and the second stator 218 to the first ECU 200 and / or the second ECU 202. The steering assembly 100 also includes a rotational sensor assembly 236 configured to detect relative rotational movement of the rotor carrier sleeve 216 or other rotating components 118 with respect to the housing 102, and a linear displacement sensor assembly 238 configured to detect relative linear movement of the steering shaft 118 with respect to the housing 102.

[0060] Figure 14 is a schematic view of a linear displacement sensor assembly 238 according to an example. The assembly includes a linear displacement sensor 244 with a linear displacement sensor length 1302 and a linear displacement target 246 configured to move between different positions along the linear displacement sensor length 1302. The linear displacement sensor 244 is configured to a detect linear position of the steering shaft 118 with respect to the housing 102 along the longitudinal axis 104. The linear displacement sensor length 1302 is less than the threaded portion length 1300. The spiral target guide track 1306 is wrapped circumferentially around the steering shaft 118 and mounted on a guide sleeve 1308.

[0061] Figures 15a and 15b are schematic views of another linear displacement sensor assembly 238 according to an example. This assembly includes a guide pin 1304 coupled to the linear displacement target 246 and configured to follow a target guide track 1306. The target guide track 1306 is spiral and has a length equal to the threaded portion length 1300. The spiral target guide track 1306 is located in a radial disc 1310 projecting circumferentially from the steering shaft 118 and mounted on a rotor carrier sleeve 216.

[0062] Turning back to Figure 1 , the steering assembly 100 will be discussed in more detail. Figure 1 shows a cross-sectional view of a steering assembly 100. The steering assembly 100 comprises a housing 102 and one or more components of the steering assembly 100 are mounted within the housing 102. The steering assembly 100 is generally elongate in construction and extends along the longitudinal axis 104. As discussed below, one or more components of the steering assembly 100 are aligned along the longitudinal axis 104.

[0063] The steering assembly 100 as shown in Figure 1 is coupled to a first tie rod 106 at a first steering assembly end 108 of the steering assembly 100. The steering assembly 100 is also coupled to a second tie rod 110 at a second steering assembly end 112 of the steering assembly 100.

[0064] The steering assembly 100 is coupled to the first tie rod 106 with a first tie rod coupling 114. The steering assembly 100 is also coupled to the second tie rod 110 with a second tie rod coupling 116. In some examples, both the first tie rod coupling 114 and the second tie rod coupling 116 are ball joints.

[0065] The steering assembly 100 comprises a steering shaft 118. The steering shaft 118 is configured to move in a linear direction along the longitudinal axis 104 with respect to the housing 102. In some examples, the longitudinal axis 104 of the steering shaft 118 is aligned with the longitudinal axis 104 of the steering assembly 100 e.g., coaxial with the longitudinal axis 104 of the steering assembly 100. In some other examples, the longitudinal axis of the steering shaft 118 extends in a direction parallel to the longitudinal axis 104 of the steering assembly 100.

[0066] A first bellow sleeve 120 and a second bellow sleeve 122 extend over and cover the steering shaft 118 respectively at the first steering assembly end 108 and the second steering assembly end 112. The first bellow sleeve 120 and the second bellow sleeve 122 protect the steering shaft 118 and the first and second tie rod couplings 114, 116 from dirt and debris. The first and second bellow sleeves 120, 122 are mounted to the housing 102 and permit relative movement of the first and second tie rods 106, 110 with respect to the housing 102 whilst maintaining a seal against the housing 102 and the first and second tie rods 106, 110.

[0067] The first and second tie rods 106, 110 are respectively connected to a first tie rod end (not shown) and a second tie rod end (not shown). The first and second tie rod ends are configured to be respectively pivotally connected to a first and second steering knuckle, for example this may be a ball-joint (not shown). The tie rods and steering knuckles are known and will not be discussed in any further detail.

[0068] As shown in Figure 1 , in some examples, the housing 102 comprises a plurality of different housing portions with differing diameters. The different housing portions in some examples are separate elements and mountable to each other. This may make assembly during manufacturing easier. For example, an ECU housing (not shown) is optionally mounted to the housing 102.

[0069] The housing 102 as shown in Figs 1 and 2 comprises a motor housing portion 124, a sensor housing portion 126 and a screw actuator housing portion 128. The motor housing portion 124 is connected to the screw actuator housing portion 128 and the screw actuator housing portion 128 is connected between the motor housing portion 124 and the sensor housing portion 126.

[0070] In some examples, the motor housing portion 124, the sensor housing portion 126 and the screw actuator housing portion 128 are a single unitary element. For example, the motor housing portion 124, the sensor housing portion 126 and the screw actuator housing portion 128 are cast or manufactured as a single component. In some other examples, the motor housing portion 124, the sensor housing portion 126 and the screw actuator housing portion 128 are separate housing elements and each of the motor housing portion 124, the sensor housing portion 126 and the screw actuator housing portion 128 are fastened together with e.g., bolts, welds, or any other suitable fastening means.

[0071] In some examples, the housing 102 comprises a first housing cap 130 connected to the motor housing portion 124 and a second housing cap 132 connected to the sensor housing portion 126. The first housing cap 130 and the second housing cap 132 in some examples are connected to the housing 102 via bolts or other screw fasteners. Preferably, the first housing cap 130 and the second housing cap 132 are removable from the housing 102. This means that the components of the steering assembly 100 are accessible if needed during maintenance of the steering assembly 100.

[0072] The housing 102 is mountable to a vehicle structure (not shown) e.g., a chassis via a first and second mounting connection (not shown) The first and second mounting connections comprise fastener holes (not shown) configured to receive screw fasteners such as bolts. However, each of the first and second mounting connections has two or more fastener holes. In this way the first and second mounting connections ensure that the steering assembly 100 is fixed to the vehicle structure. The first and second mounting connections with respect to the housing 102 can be modified depending on the form, size and shape of vehicle structure and the mounting locations on the vehicle structure. In some examples, there are preferably three or more mounting connections such that the steering assembly 100 is fixed in a plane with respect to the vehicle structure.

[0073] In some examples, the vehicle is an electric vehicle e.g., an electric car or electric truck. In some other examples, the vehicle is a vehicle with an internal combustion engine or any other type of motorised vehicle. The steering assembly 100 as discussed in reference to the accompanying Figs can be used with any suitable vehicle with at least one steerable wheel. In some examples, the steering assembly 100 is a steer-by-wire steering assembly 100. The term steer-by-wire means that there is no mechanical linkage between a user input e.g., a steering wheel (not shown) or control input device and the steering assembly 100. For example, the steering assembly 100 does not comprise a steering wheel connected to a rack and pinion mechanism (not shown).

[0074] Instead, control instructions are provided from one or more electronic control units (ECU) 200, 202 configured to control the steering assembly 100. As mentioned above, the first and second ECUs 200, 202 are mounted in an ECU housing (not shown). In some examples, the ECU housing is mounted to the housing 102. In some other examples, the ECU housing is mounted in a separate location to the steering assembly 100 or remote from the housing 102 connected by data and power connections to the steering assembly 100 as shown in the Figures.

[0075] The first and second ECUs 200, 202 optionally receive control instructions from a vehicle control unit (VCU) 204 (best shown in Figure 7). Data connections to and from the first and second ECUs 200, 202 have not been shown in the Figures for the purposes of clarity. In some less preferred examples, the steering assembly 100 is optionally configured to receive control instructions directly from the VCU 204 and there are no ECUs 200, 202.

[0076] Hereinafter reference to the steer-by-wire steering assembly 100 will be made using the term “steering assembly 100”.

[0077] In some examples, the steering assembly 100 is controlled in response to control instructions from a user input e.g., an electrically connected steering wheel. Alternatively other user input devices can be used with the steering assembly 100 e.g., a joystick, or any other suitable user input control device.

[0078] Additionally, or alternatively, the steering assembly 100 is controlled from control instructions received from the first or second ECUs 200, 202 or the VCU 204. For example, the steering assembly 100 is optionally a subassembly of an autonomous vehicle. However, even if the steering assembly 100 is used in an autonomous vehicle, it may be preferable to allow control of the steer-by-wire steering assembly 100 from a user input device e.g., an electrically connected steering wheel. This will permit user- controlled testing and review of the steering assembly 100 in an autonomous vehicle on the roads.

[0079] Turning to Figure 2, the steering assembly 100 will be discussed in more detail.

[0080] The steering assembly 100 comprises a motor assembly 206 having first motor 208 and a second motor 210. The first motor 208 and the second motor 210 are mounted within the motor housing portion 124. In some examples, the first motor 208 is controlled by the first ECU 200 and the second motor 210 is controlled by the second ECU 202. Additionally, or alternatively, either the first motor 208 and I or the second motor 210 is configured to receive control instructions from any of the first or second ECUs 200, 202 or the VCU 204. Reference hereinafter to the control of the steering assembly 100 is made in reference to the first ECU 200 and the second ECU 202 issuing control instructions to the first motor 208 and the second motor 210. The first ECU 200 is configured to issue control instructions to either the first motor 208 and I or the second motor 210. Similarly, the second ECU 202 is configured to issue control instructions to either the first motor 208 and I or the second motor 210. The first ECU 200 and the second ECU 202 can operate independently of each other or alternatively together in unison. This means that control functionality discussed in the present disclosure with respect to the first ECU 200 is applicable to the second ECU 202 as well.

[0081] In some preferred examples, the first ECU 200 is configured to control the first motor 208 and the second ECU 202 is configured to control the second motor 210. The first and second ECUs 200, 202 are connected with an ECU data connection 222 (best shown in Figure 7) and are configured to communicate an operational status to each other via the ECU data connection 222. The first and second ECUs 200, 202 are configured to transmit and receive fault states to either the other ECUs 200, 202 and I or the VCU 204. In this way, the first ECU 200 can determine whether there is a fault state with the second ECU 202 or the second motor 210 from system status messages sent from the second ECU 202. Similarly, the second ECU 202 can determine whether there is a fault state with the first ECU 200 or the first motor 208 from system status messages sent from the first ECU 200. In the event that e.g., the second ECU 202 or the second motor 210 experiences a fault or malfunction, the second ECU 202 either sends a system status message comprising a fault indication to the first ECU 200 or no system status message is sent. On receipt of the system status message comprising a fault indication or the first ECU 200 determining that no system status message has been received, the first ECU 200 determines that there is a fault or malfunction with the second ECU 202 or the second motor 210. Accordingly, the first ECU 200 assumes total control of the steering assembly 100 and the first ECU 200 issues control instructions to the first motor 208. In this way, the first ECU 200 and the first motor 208 can still operate the steering assembly 100 when either the second ECU 202 or the second motor 210 have failed. The second ECU 202 comprises a similar functionality to the first ECU 200 and is configured to assume total control of the steering assembly 100 if the second ECU 202 determines that either the first ECU 200 or the first motor 208 has failed.

[0082] The first motor 208 comprises a first stator 212 and a first rotor 214. The term “motor” means a set of motor windings mounted in a stator which are configured to rotate at least one rotor when energised. The first stator 212 comprises one or more motor windings configured to cause the first rotor 214 to rotate when energised. The first rotor 214 is mounted on a rotor carrier sleeve 216 and the rotor carrier sleeve 216 is configured to rotate when the first rotor 214 rotates. The first rotor 214 is fixed with respect to the rotor carrier sleeve 216. In some examples the first rotor 214 is press- fit onto the rotor carrier sleeve 216. In some alternative examples, a tolerance ring (not shown) is used instead of a press fit. A tolerance ring may be beneficial because a tolerance ring is easier to install with less force and this reduces the risk of surface damage to the rotor carrier sleeve 216 when assembled.

[0083] The second motor 210 comprises a second stator 218 and a second rotor 220. The second stator 218 comprises one or more motor windings configured to cause the second rotor 220 to rotate when energised. The second rotor 220 is also mounted on the rotor carrier sleeve 216 and the rotor carrier sleeve 216 is configured to rotate when the second rotor 220 rotates. The second rotor 220 is also fixed with respect to the rotor carrier sleeve 216. In some examples, similarly the second rotor 220 is press-fit onto the rotor carrier sleeve 216. In some other examples, the first rotor 214 and the second rotor 220 are integral with the rotor carrier sleeve 216. In this example the first rotor 214, the second rotor 220 and the rotor carrier sleeve 216 are a unitary element.

[0084] In some other examples, the motor assembly 206 comprises only a first stator 212 which comprises a first set of motor windings and a second set of motor windings. The first stator 212 with first and second sets of motor windings is configured to rotate the first rotor 214 when either the first or second sets of motor windings are energised. In this example, there is only a single first rotor 214. Indeed, either the first set of motor windings or the second set of motor windings is configured to rotate the first rotor 214 when energised. In this example, the first motor 208 can be considered to be a combination of the first stator 212 with the first set of motor windings and the first rotor 214. The second motor 210 can be considered to be a combination of the first stator 212 with the second set of motor windings and the first rotor 214.

[0085] In another example, the motor assembly 206 comprises a first stator 212 which comprises a first set of motor windings and a second set of motor windings in combination with the first rotor 214 and the second rotor 220. The first stator 212 with the first set of motor windings is configured to rotate the first rotor 214 when energised. The first stator 212 with second set of motor windings is configured to rotate the second rotor 220 when energised. In this example, the first motor 208 can be considered to be a combination of the first stator 212 with the first set of motor windings and the first rotor 214. The second motor 210 can be considered to be a combination of the first stator 212 with the second set of motor windings and the second rotor 220.

[0086] In another example, the motor assembly 206 comprises a first stator 212 which comprises a first plurality of motor windings 3312 and a second plurality of motor windings 3314 in combination with the first rotor 214 and the second rotor 220. The first stator 212 with the first plurality of motor windings 3312 is configured to rotate the first rotor 214 when energised. The first stator 212 with second plurality of motor windings 3314 is configured to rotate the second rotor 220 when energised. In this example, the first motor 208 can be considered to be a combination of the first stator 212 with the first plurality of motor windings 3312 and the first rotor 214. The second motor 210 can be considered to be a combination of the first stator 212 with the second plurality of motor windings 3314 and the second rotor 220.

[0087] The first and second motors 208, 210 in other examples can have any suitable number of sets of motor windings e.g., two, three, four etc sets of motor windings with multiple phases e.g., 3 or 6 phases.

[0088] It should be noted that the previously discussed variations in the motor assembly 206 and the first and second motors 208, 210 and the arrangement of the first and second stators 212, 218 and the first and second rotors 214, 220 are applicable to any of the examples discussed in reference to the Figures.

[0089] The first and second motors 208, 210 in some examples are induction motors. In some other examples the first and second motors 208, 210 are any other suitable type of electric motor e.g., a brushless DC electric motor (BLDC), synchronous motor, 3 phase induction motor etc.

[0090] The preferred examples as shown in Figure 2 will now be discussed in more detail. That is, the first motor 208 comprising the first stator 212 and the first rotor 214 and the second motor 210 comprising the second stator 218 and the second rotor 220.

[0091] In this way, either the second motor 210 or the first motor 208 are configured to cause rotation of the rotor carrier sleeve 216. Accordingly, the second motor 210 or the first motor 208 are configured to provide a torque and rotational speed to the rotor carrier sleeve 216. For example, if one of the first motor 208 or the second motor 210 develops a fault, the other of the first motor 208 or the second motor 210 can still rotate the rotor carrier sleeve 216. A “fault” means anything relating to operation of the ECU, sensors, or motor. For example, the second ECU 202, the second motor 210 or one or more sensors develop a fault. The part of the steering assembly 100 comprising the second ECU 202 and the second motor 210 then shuts down and the first ECU 200 is configured to provide functionality by issuing control instructions to the first motor 208. This means that the steering assembly 100 is operational even if one of the first or second motor 208, 210 is not operational. Accordingly, this provides fail- operational redundancy. Whilst Figure 2 shows a first motor 208 and a second motor 210 in the steering assembly 100, in other examples there can be any suitable number of motors mounted within the motor housing portion 124. Furthermore, as previously mentioned there can be multiple motor windings. This means in some examples there can be one physical motor but multiple separate electrical motor circuits providing separate motor functionality. For example, there can be three motors, four motors etc. The first and second motors 208, 210 as shown in Figure 2 are adjacent to each other within the motor housing portion 124. A stator spacer (not shown) is optionally mounted on the steering shaft 118 to ensure that the first motor 208 and the second motor 210 do not interfere with each other when actuated. The stator spacer is not necessary though and not shown in the Figures.

[0092] In some examples the first stator 212 and the second stator 218 are press-fit into the motor housing portion 124. The press-fit provides an interference fit between the first stator 212 and the second stator 218 and the motor housing portion 124. This means that friction between the first stator 212, the second stator 218 and the motor housing portion 124 ensures that the first stator 212, the second stator 218 and the motor housing portion 124 are fixed with respect to each other.

[0093] As mentioned above, in some examples the first rotor 214 and the second rotor 220 are press-fit onto the rotor carrier sleeve 216. First and second rotors 214, 220 are separated on the rotor carrier sleeve 216 via an optional rotor spacer (not shown). The rotor spacer may also press-fit on the rotor carrier sleeve 216 between the first rotor 214 and the second rotor 220 to ensure separation between the first rotor 214 and the second rotor 220. The rotor spacer is not necessary though and not shown in the Figures.

[0094] The term “press-fit” used to describe the accompanying Figs provides connection between two components having an interference fit. This means that the connection between the two components generates sufficient frictional force that the two components are fixed with respect to each other. However, in some other examples, any other suitable means can be used for fixing two components with respect to each other e.g., a tolerance ring, welding, adhesive, bonding, bolting, interlocking features etc.

[0095] The rotor carrier sleeve 216 is an elongate tube which extends along the longitudinal axis 104. The rotor carrier sleeve 216 is rotatable about the steering shaft 118. The rotor carrier sleeve 216 is coaxial with the steering shaft 118. A first sleeve end 224 of the rotor carrier sleeve 216 is rotatably mounted to the housing 102 via a rotor carrier sleeve bearing 226. In some examples, the rotor carrier sleeve bearing 226 is press- fit onto the rotor carrier sleeve 216 and the rotor carrier sleeve bearing 226 is press-fit into a reciprocal bearing recess 228 in the first housing cap 130.

[0096] A second sleeve end 230 of the rotor carrier sleeve 216 is connected to a screw actuator 232. The screw actuator 232 is mounted in the screw actuator housing portion 128.

[0097] The screw actuator 232 is configured to engage with a threaded portion 234 on the steering shaft 118. When the screw actuator 232 rotates, the screw actuator 232 is configured to cause a linear displacement of the steering shaft 118 along the longitudinal axis 104. Depending on the direction of rotation of the screw actuator 232, the steering shaft 118 moves in a direction towards the first steering assembly end 108 or a direction towards the second steering assembly end 112. Accordingly, the torque, direction, and speed that the first and I or second motor 208, 210 rotate determines the speed, direction, and magnitude of the linear displacement of the steering shaft 118.

[0098] As shown in Figure 2 the screw actuator 232 is in some examples a ball screw actuator 232. In some other examples, the screw actuator 232 is a roller screw actuator (not shown) configured to engage the threaded portion 234. In some other examples, the screw actuator 232 is any suitable rotating mechanism configured to engage one or more parts of the groove of the threaded portion 234 whilst rotating.

[0099] In order for the first and second ECUs 200, 202 to determine the status of one or more components of the steering assembly 100, the steering assembly 100 comprises a plurality of sensors connected to the first and second ECUs 200, 202. The plurality of sensors each are configured to generate and send a signal which the first and I or second ECUs 200, 202 determine the linear displacement of the steering shaft 118 with respect to the housing 102.

[0100] The different sensor arrangements in the steering assembly 100 which provide sensor redundancy and allow a fail-operational arrangement will now be discussed.

[0101] In some examples sensor housing portion 126 comprises at least one rotational sensor assembly 236 configured to detect relative rotational motion of the rotor carrier sleeve 216 with respect to the housing 102 or the sensor housing portion 126.

[0102] As shown in Figure 2 the first rotational sensor assembly 236 is configured to detect rotational movement of the rotor carrier sleeve 216. In some alternative examples, the first rotational sensor assembly 236 is mounted to detect rotational movement of one or more of the other rotating components e.g., the first or second rotors 214, 220. The first rotational sensor assembly 236 comprises a rotary sensor 240 configured to detect relative rotational movement of a rotating sensor target 242. In some examples the rotary sensor 240 is a Hall sensor.

[0103] Alternatively, the at least one rotary sensor 240 is any other suitable sensor configured to detect relative movement of the rotor carrier sleeve 216 with respect to the housing 102. For example, the at least one rotary sensor 240 is an optical sensor configured to detect markings on the rotor carrier sleeve 216. In some other examples the at least one rotary sensor 240 is an inductive sensor (not shown) comprising a rotational target (not shown) mounted to the rotor carrier sleeve 216. The inductive sensor is configured to generate an EMF e.g., an Eddie current when the rotational target moves past a coil in the inductive sensor.

[0104] Linear displacement sensor assembly

[0105] In some examples the steering assembly 100 comprises at least one linear displacement sensor assembly 238 mounted on the steering shaft 118. The at least one linear displacement sensor assembly 238 is configured to detect relative linear movement or the position of the steering shaft 118 in a direction along the longitudinal axis 104 with respect to the housing 102. In some examples, the at least one linear displacement sensor assembly 238 is configured to continuously detect the linear displacement of the steering shaft 118 through the entire possible range of movement of the steering shaft 118. This means that the first or second ECU 200, 202 are configured to constantly determine the absolute linear displacement of the steering shaft 118 from the signal received from the at least one linear displacement sensor assembly 238.

[0106] In some examples, the linear displacement sensor assembly 238 is mounted on one side of the steering assembly 100. In some examples, the linear displacement sensor assembly 238 comprises a linear displacement sensor portion 244 and a linear displacement target portion 246. The linear displacement sensor portion 244 is configured to detect relative movement of the linear displacement target portion 246 thereto. In some examples the linear displacement target portion 246 is mounted on the steering shaft 118 and the linear displacement sensor portion 244 is mounted on the housing 102. In some other examples the linear displacement target portion 246 is mounted on the housing 102 and the linear displacement sensor portion 244 is mounted on the steering shaft 118.

[0107] In some examples, the linear displacement sensor assembly 238 comprises one or more of an optical sensor, a linear resistive sensor, a linear hall-effect sensor, linear voltage displacement transducer, linear potentiometer, a potentiometric linear transducer, or a hall-effect sensor.

[0108] In some examples, the linear displacement sensor portion 244 and the linear displacement target portion 246 are configured to provide a high degree of accuracy and reliability in detecting the relative movement of the steering shaft 118. The linear displacement sensor portion 244 may comprise a linear displacement sensor, such as a potentiometer, a Hall effect sensor, or an optical encoder, which is capable of detecting the position of the linear displacement target portion 246 relative to the linear displacement sensor portion 244. The linear displacement target portion 246 may be mounted on the steering shaft 118 or the sensor housing 316, depending on the specific configuration of the sensor assembly 238. The linear displacement sensor portion 244 and the linear displacement target portion 246 may be arranged in various configurations to optimise the performance of the sensor assembly 238. For example, the linear displacement sensor portion 244 may be mounted on the housing 102, while the linear displacement target portion 246 is mounted on the steering shaft 118 or the sensor housing 316. Alternatively, the linear displacement sensor portion 244 may be mounted on the steering shaft 118 or the sensor housing 316, while the linear displacement target portion 246 is mounted on the housing 102. In either configuration, the linear displacement sensor portion 244 and the linear displacement target portion 246 are arranged such that they can detect the relative movement of the steering shaft 118 with respect to the housing 102.

[0109] As shown in Figures 3 to 6, in some examples, one of the linear displacement sensor portion 244 and the linear displacement target portion 246 are mounted in a sensor housing 316 that is fixed with respect to the steering shaft 118. The sensor housing 316 may be configured to slide within a sensor channel 302 in the housing 102, which constrains the movement of the sensor housing 316 and the steering shaft 118 in a direction parallel to the longitudinal axis 104. This configuration ensures that the linear displacement sensor portion 244 and the linear displacement target portion 246 maintain a consistent and accurate alignment during the operation of the steer-by-wire steering assembly 100. One of the linear displacement sensor portion 244 and the linear displacement target portion 246 are mounted fully or partially in the sensor housing 316. This means that the linear displacement sensor portion 244 and the linear displacement target portion 246 can sit completely within the sensor housing 316 or partially protrude out of the sensor housing 316.

[0110] The sensor housing 316 may be mounted on the steering shaft 118 using various methods, such as a set screw, press fit, or welding. This allows the sensor housing 316 to be securely attached to the steering shaft 118, ensuring that the linear displacement sensor portion 244 and the linear displacement target portion 246 remain in the correct position relative to each other during the operation of the steer-by-wire steering assembly 100.

[0111] The use of a sensor housing 316 and a sensor channel 302 in the steer-by-wire steering assembly 100 provides several advantages. First, the sensor housing 316 and the sensor channel 302 help to protect the linear displacement sensor portion 244 and the linear displacement target portion 246 from damage due to external forces or debris. Second, the sensor housing 316 and the sensor channel 302 ensure that the linear displacement sensor portion 244 and the linear displacement target portion 246 maintain a consistent and accurate alignment during the operation of the steer-by-wire steering assembly 100 by preventing rotation of the steering shaft 118 about the longitudinal axis 104. Finally, the sensor housing 316 and the sensor channel 302 provide a simple and effective means for mounting the linear displacement sensor portion 244 and the linear displacement target portion 246 on the steering shaft 118, which simplifies the assembly and maintenance of the steer-by-wire steering assembly 100.

[0112] In some examples, the sensor channel 302 is located within the housing sleeve portion 300 of the housing 102. As can be seen from Figure 1 , the housing sleeve portion 300 projects from a side of the housing 102. The housing sleeve portion 300 may be designed to protect the linear displacement sensor assembly 238 and other components of the steer-by-wire steering assembly 100 from external factors, such as dust, debris, and moisture. The housing sleeve portion 300 may be made from a variety of materials, such as metals, plastics, or composites, depending on the specific requirements of the application. Indeed, the housing sleeve portion 300 may be made from the same material as the housing 102.

[0113] The sensor channel 302 may be integrally formed with the housing sleeve portion 300 or may be formed as a separate component that is attached to the housing sleeve portion 300. In some examples, the sensor channel 302 may be formed by a mounting assembly 306 that is fixed to the housing sleeve portion 300, as described in more detail below.

[0114] In some examples, the sensor channel 302 comprises a first channel engagement surface 304 and a second channel engagement surface 324. These engagement surfaces are configured to engage with corresponding first housing engagement surface 318 and second housing engagement surface 326 of the sensor housing 316. This engagement ensures that the sensor housing 316 and the steering shaft 118 are constrained in a direction parallel to the longitudinal axis 104, providing accurate and reliable detection of the steering shaft 118 movement.

[0115] The first channel engagement surface 304 may be configured to engage the first housing engagement surface 318 when the screw actuator 232 rotates in a first direction, while the second channel engagement surface 324 may be configured to engage the second housing engagement surface 326 when the screw actuator 232 rotates in a second direction. This engagement configuration ensures that the sensor housing 316 and the steering shaft 118 are constrained in both directions of movement, preventing the steering shaft 118 from rotating about the longitudinal axis 104.

[0116] In some examples, the sensor channel 302 may comprise additional engagement surfaces or features to further constrain the movement of the sensor housing 316 and the steering shaft 118. These additional features may include, for example, guide rails, grooves, or other structures that help to maintain the alignment and stability of the sensor housing 316 and the steering shaft 118 during operation.

[0117] In one example, the steer-by-wire steering assembly 100 includes a mounting assembly 306 that is fixed to the housing sleeve portion 300. The mounting assembly 306 comprises at least one elongate rail 308 that defines the sensor channel 302 when mounted to the housing sleeve portion 300. The elongate rail 308 may be made from a low friction hard wearing material, such as nylon, Delrin, PTFE (polytetrafluoroethylene), UHMW (ultra-high molecular weight polyethylene), acetal, aluminium, steel, titanium, or composite materials. The elongate rail 308 may also be coated with a low friction material, such as Teflon, silicone, graphite, molybdenum disulfide, polyurethane, or polyethylene, to reduce friction between the sensor housing 316 and the elongate rail 308 during operation.

[0118] In some examples, the mounting assembly 306 further comprises fasteners 310 configured to clamp the at least one elongate rail 308 to an inner surface of the housing sleeve portion 300. The fasteners 310 may include screws, bolts, or other suitable fastening devices. The fasteners 310 may comprise a projecting flange 314 which is configured to engage a shoulder portion 312 on the elongate rail 308. This engagement ensures a secure connection between the elongate rail 308 and the housing sleeve portion 300, preventing unwanted movement or dislodgement of the elongate rail 308 during operation. In some examples, the fasteners 310 are screw fasteners which are engaged with reciprocal threaded holes in the housing sleeve portion 300. The screw fasteners 310 can comprise a “T-shaped” cross section to provide the projecting flange 314.

[0119] The mounting assembly 306 may be configured to allow for easy installation and removal of the elongate rail 308, facilitating maintenance and replacement of the elongate rail 308 when necessary. This modular design can improve the overall reliability and serviceability of the steer-by-wire steering assembly 100.

[0120] The at least one elongate rail 308, when mounted to the housing sleeve portion 300, defines the sensor channel 302. The sensor channel 302 is configured to receive the sensor housing 316 and constrain the movement of the sensor housing 316 and the steering shaft 118 in a direction parallel to the longitudinal axis 104 as discussed above. This constraint ensures proper linear movement of the steering shaft 118 and prevents unwanted rotation of the steering shaft 118 during operation.

[0121] In some examples, the elongate rail 308 may be shaped to provide a smooth and continuous surface for the sensor housing 316 to slide along, minimising friction and wear between the sensor housing 316 and the elongate rail 308. This can improve the overall performance and lifespan of the steer-by-wire steering assembly 100.

[0122] The elongate rail 308 may also be designed to provide shock protection to the sensor assembly 238, preventing damage to the linear displacement sensor portion 244 and the linear displacement target portion 246 during operation. This can further enhance the reliability and durability of the steer-by-wire steering assembly 100.

[0123] In one example, the sensor target housing 316 includes a shaft engagement sleeve 320 that is configured to mount around the steering shaft 118. The sensor target housing 316 together with the shaft engagement sleeve 320 provides an anti-rotation device for the steering shaft 118. Since the sensor target housing 316 is configured to slide within a sensor channel 302, this prevents the steering shaft 118 from rotating and ensures proper linear movement along the longitudinal axis 104. In some examples, the shaft engagement sleeve 320 is designed to be mounted on the steering shaft 118 using various methods, such as a set screw, press fit, or welding. The shaft engagement sleeve 320 is fixed with respect to the steering shaft 118 so that when the steering shaft 118 moves, the sensor target housing 316 also moves accordingly. This configuration ensures that the sensor assembly 238 accurately detects the relative movement of the steering shaft 118 with respect to the housing 102.

[0124] The shaft engagement sleeve 320 may comprise a low friction material, such as nylon, Delrin, PTFE (polytetrafluoroethylene), UHMW (ultra-high molecular weight polyethylene), acetal, aluminium, steel, titanium, or composite materials, to reduce friction between the shaft engagement sleeve 320 and the sensor channel 302. This reduction in friction can improve the accuracy and reliability of the sensor assembly 238 and reduce wear on the components. However, this is optional because the shaft engagement sleeve 320 may not engage the sensor channel 302. In other words, in some examples, only the surfaces of the sensor target housing 316 engage the sensor channel 302.

[0125] In some examples, the shaft engagement sleeve 320 includes a central bore 322 that is configured to receive the steering shaft 118. The central bore 322 allows the steering shaft 118 to be inserted into the shaft engagement sleeve 320, ensuring a secure and stable connection between the steering shaft 118 and the sensor target housing 316.

[0126] The central bore 322 may be designed with a precise fit to the steering shaft 118, ensuring that the shaft engagement sleeve 320 remains securely attached to the steering shaft 118 during operation. This secure attachment helps maintain the accuracy and reliability of the sensor assembly 238 by preventing unwanted movement or rotation of the steering shaft 118 relative to the sensor target housing 316.

[0127] In summary, the shaft engagement sleeve 320 and central bore 322 provide a secure and stable connection between the steering shaft 118 and the sensor target housing 316, ensuring accurate and reliable detection of the relative movement of the steering shaft 118 with respect to the housing 102. In one example, e.g., as shown in Figures 3 to 6 the steer-by-wire steering assembly 100 comprises a dual sensor assembly configuration, which includes a first sensor assembly 238 and a second sensor assembly 500 (best shown in Figure 5). The dual sensor assembly configuration provides redundancy and increased reliability in detecting the relative movement of the steering shaft 118 with respect to the housing 102. This redundancy can help ensure the proper functioning of the steer-by-wire steering assembly 100 and reduce the risk of failure or malfunction.

[0128] In some examples, the first sensor assembly 238 and the second sensor assembly 500 are identical in design and function. Each sensor assembly 238, 500 comprises a linear displacement sensor portion 244, 244b and a linear displacement target portion 246, 246b configured to detect relative movement of the steering shaft 118 with respect to the housing 102. The linear displacement sensor portion 244, 244b and the linear displacement target portion 246, 246b may be mounted in a sensor housing 316 fixed with respect to the steering shaft 118. The sensor housing 316 may be configured to slide within a sensor channel 302 in the housing 102, as described in previous sections.

[0129] In one example, the first sensor assembly 238 and the second sensor assembly 500 are linear displacement sensor assemblies 238, 500 as previously discussed. The linear displacement sensor assemblies 238, 500 are configured to detect the linear movement of the steering shaft 118 along the longitudinal axis 104 when the screw actuator 232 rotates. The use of multiple linear displacement sensor assemblies 238, 500 provides accurate and precise measurement of the movement of the steering shaft 118, which is for the proper functioning of the steer-by-wire steering assembly 100. This also increases the redundancy of the steer-by-wire steering assembly 100.

[0130] In some examples, the first sensor assembly 238 and the second sensor assembly 500 are mounted at different positions on the steering shaft 118. This arrangement provides additional redundancy and reliability in detecting the relative movement of the steering shaft 118 with respect to the housing 102. By mounting the sensor assemblies 238 at different positions on the steering shaft 118, the steer-by-wire steering assembly 100 can continue to function even if one of the sensor assemblies 238 fails or malfunctions.

[0131] The first sensor housing 316 and a second sensor target housing 502 are both connected to the shaft engagement sleeve 320. The shaft engagement sleeve 320 is configured to mount around the steering shaft 118 as discussed previously. Each of the first sensor housing 316 and a second sensor target housing 502 are configured to slide within a sensor channel 302. For the purposes of clarity only one sensor channel 302 is labelled in the Figures. Nevertheless, both first sensor housing 316 and a second sensor target housing 502 are configured to limit the rotation of the steering shaft 118 about the longitudinal axis 104.

[0132] In some examples, the first sensor housing 316 and a second sensor target housing 502 are mounted diametrically opposite on the steering shaft 118. However, in other examples, the first sensor housing 316 and a second sensor target housing 502 can be mounted at different circumferential spacings around the steering shaft 118. E.g., at 90 degree, 120 degree angular separation. In other examples there can be any number sensor housing 316 mounted on the steering shaft 118 to prevent rotation thereof. In other examples, the first sensor housing 316 can comprise the linear displacement sensor assembly 238 and the second sensor target housing 502 does not contain a linear displacement sensor assembly 238. In this case, the second sensor target housing 502 is for aiding the anti-rotational functionality of the first sensor housing 316.

[0133] In summary, the dual sensor assemblies 238, 500 configuration and mounting in the steer-by-wire steering assembly 100 provide redundancy and increased reliability in detecting the relative movement of the steering shaft 118 with respect to the housing 102. The use of identical sensor assemblies 238 mounted at different positions on the steering shaft 118 ensures the proper functioning of the steer-by-wire steering assembly 100 and reduces the risk of failure or malfunction.

[0134] Rotation sensor assembly

[0135] The rotary sensor assembly 236 will now be discussed in more detail with respect to Figures 2, and 8 to 11. In one example, the steer-by-wire steering assembly 100 includes a rotor carrier sleeve 216 that is operatively coupled between the motor assembly 206 and the screw actuator 232. The rotor carrier sleeve 216 is configured to rotate about the longitudinal axis 104, enabling the transfer of rotational motion from the motor assembly 206 to the screw actuator 232. The rotor carrier sleeve 216 comprises an end cup formation 4300, which is configured to receive the screw actuator 232, such as a ball screw nut 232.

[0136] In some examples, the end cup formation 4300 of the rotor carrier sleeve 216 comprises a sleeve inner threaded portion 4302 and a sleeve outer threaded portion 4304. The sleeve inner threaded portion 4302 is configured to engage with the rotary sensor target 242, while the sleeve outer threaded portion 4304 is configured to engage with an outer locking nut 4310.

[0137] In one example, the rotary sensor target 242 comprises a target threaded portion 4316 that is configured to engage with the sleeve inner threaded portion 4302 of the rotor carrier sleeve 216. This engagement allows the rotary sensor target 242 to be securely mounted on the rotor carrier sleeve 216 and fix the screw actuator 232 with respect to the rotor carrier sleeve 216. The engagement between the sleeve outer threaded portion 4304 and the outer locking nut 4310 enables the clamping of the rotor carrier sleeve 216 to the outer bearing 4314, ensuring a secure and stable connection between these components.

[0138] Whilst the Figures show the rotary sensor target 242 mounted to the rotor carrier sleeve 216 via a screw thread, the rotary sensor target 242 can be mounted to the rotor carrier sleeve 216 via any suitable means. For example, the rotary sensor target 242 can be press fit into the end cup formation 4300 of rotor carrier sleeve 216. Alternatively, the rotary sensor target 242 can be welded or adhered to the end cup formation 4300 of rotor carrier sleeve 216.

[0139] Accordingly, the rotary sensor target 242 is configured to mount on the rotor carrier sleeve 216 and engage the screw actuator 232 between the rotary sensor target 242 and rotor carrier sleeve 216 and fix the screw actuator 232 with respect to the rotor carrier sleeve 216. In some examples, the rotor carrier sleeve 216 may comprise a key slot 4306 that is configured to receive a key element 4312. The key element 4312 is designed to engage the internal surface of the outer bearing 4314 and align and maintain the position of the rotor carrier sleeve 216 with respect to the outer bearing 4314.

[0140] In one example, the key element 4312 engages the key slot 4306 in the rotor carrier sleeve 216 and the screw actuator 232, keeping the screw actuator 232, the rotor carrier sleeve 216, and the outer bearing 4314 fixed with respect to each other. This configuration ensures proper alignment and positioning of the components within the steer-by-wire steering assembly 100, contributing to the overall stability and performance of the steering assembly 100.

[0141] The integration of the key slot 4306 and the key element 4312 in the rotor carrier sleeve 216 provides several advantages. For instance, it simplifies the assembly process by reducing the number of separate components required for alignment and positioning. Additionally, it enhances the overall stability and performance of the steer-by-wire steering assembly 100 by ensuring that the screw actuator 232, the rotor carrier sleeve 216, and the outer bearing 4314 remain fixed with respect to each other during operation.

[0142] The steer-by-wire steering assembly 100, in one or some examples, includes a rotational sensor assembly 236 that is designed to measure and detect the relative rotational movement of a rotary sensor target 242. The rotational sensor assembly 236 comprises a rotary sensor 240 and a rotary sensor target 242, which are configured to work together to detect the relative rotational movement of the rotary sensor target 242.

[0143] In one or some examples, the rotary sensor 240 may be selected from one or more types of rotary sensors, including but not limited to an optical rotary sensor, a magnetic rotary sensor, a capacitive rotary sensor, an inductive rotary sensor, a Hall effect rotary sensor, and a resolver. Each of these types of rotary sensors has its own unique advantages and characteristics, which may be suitable for different applications and requirements in the steer-by-wire steering assembly 100. Optical rotary sensors, for example, use light to detect the relative rotational movement of the rotary sensor target 242. These sensors are known for their high resolution and accuracy, making them suitable for applications where precise measurements are required.

[0144] Magnetic rotary sensors, on the other hand, use magnetic fields to detect the relative rotational movement of the rotary sensor target 242. These sensors are known for their robustness and ability to operate in harsh environments, making them suitable for applications where the steer-by-wire steering assembly 100 may be exposed to extreme conditions.

[0145] Capacitive rotary sensors use changes in capacitance to detect the relative rotational movement of the rotary sensor target 242. These sensors are known for their ability to operate in a wide range of temperatures and humidity levels, making them suitable for applications where the steer-by-wire steering assembly 100 may be exposed to varying environmental conditions.

[0146] Inductive rotary sensors use changes in inductance to detect the relative rotational movement of the rotary sensor target 242. These sensors are known for their ability to operate in the presence of dirt, dust, and other contaminants, making them suitable for applications where the steer-by-wire steering assembly 100 may be exposed to dirty or dusty environments.

[0147] Hall effect rotary sensors use changes in magnetic fields to detect the relative rotational movement of the rotary sensor target 242. These sensors are known for their ability to operate in a wide range of temperatures and are resistant to wear and tear, making them suitable for applications where the steer-by-wire steering assembly 100 may be exposed to varying temperatures and long-term use.

[0148] Resolver sensors use changes in the amplitude and phase of an input signal to detect the relative rotational movement of the rotary sensor target 242. These sensors are known for their high accuracy and ability to operate in harsh environments, making them suitable for applications where the steer-by-wire steering assembly 100 may be exposed to extreme conditions.

[0149] In one or some examples, the rotary sensor 240 is configured to detect the relative rotational movement of the rotary sensor target 242, which is mounted on the rotor carrier sleeve 216. The rotary sensor target 242 may comprise a target threaded portion 4316 that is configured to engage with the sleeve inner threaded portion 4302 of the rotor carrier sleeve 216. This engagement allows the rotary sensor target 242 to be fixed with respect to the rotor carrier sleeve 216, enabling the rotary sensor 240 to accurately detect the relative rotational movement of the rotary sensor target 242.

[0150] The detection of the relative rotational movement of the rotary sensor target 242 by the rotary sensor 240 provides valuable information about the position and movement of the steering shaft 118 in the steer-by-wire steering assembly 100. This information can be used to control the operation of the motor assembly 206 and the screw actuator 232, ensuring precise and accurate control of the steering shaft 118 and, ultimately, the steering of the vehicle.

[0151] The use of the rotational sensor assembly 236 in the steer-by-wire steering assembly 100 provides several advantages. For example, the ability to accurately detect the relative rotational movement of the rotary sensor target 242 allows for precise control of the steering shaft 118, improving the overall performance and safety of the vehicle. Additionally, the integration of the rotary sensor target 242 with the rotor carrier sleeve 216 and the screw actuator 232 reduces the overall size and complexity of the steering assembly 100, making it more compact and easier to manufacture and assemble.

[0152] In one example, the steer-by-wire steering assembly 100 comprises a screw actuator 232, an outer bearing 4314, and an end cup formation 4300, all mounted in the same radial plane 4318. This configuration allows for a more compact and efficient design, as the components are positioned in close proximity to one another, reducing the overall size and complexity of the steering assembly 100.

[0153] In some examples, the screw actuator 232 is mounted entirely within the end cup formation 4300 of the rotor carrier sleeve 216. The end cup formation 4300 is configured to receive the screw actuator 232 and provide a secure and stable connection between the screw actuator 232 and the rotor carrier sleeve 216. The outer bearing 4314 is mounted around the rotor carrier sleeve 216 and is positioned in the same radial plane 4318 as the screw actuator 232 and the end cup formation 4300. This arrangement allows for a more compact design, as the components are closely aligned and integrated with one another.

[0154] The end cup formation 4300 may comprise a cup shoulder portion 4308 configured to abut and position the outer bearing 4314. This configuration ensures that the outer bearing 4314 is properly aligned and maintained in position with respect to the rotor carrier sleeve 216, providing a stable and secure connection between the components.

[0155] In some examples, the screw actuator 232 is a ball screw nut 232 with a reduced length from 10 to 6 complete revolutions of engaging ball bearings. This reduction in length allows for sufficient force to still be transmitted between the ball screw actuator 232 and the threaded surface of the steering shaft 118, while also reducing the longitudinal length of the actuator. This reduced length contributes to the overall compactness and efficiency of the steer-by-wire steering assembly 100, as it allows for a smaller and more streamlined design.

[0156] As mentioned above, the ball screw nut 232 may be completely retained within the end cup formation 4300 of the rotor carrier sleeve 216, further contributing to the compactness of the steer-by-wire steering assembly 100. This configuration ensures that the ball screw nut 232 is securely held in place and properly aligned with the other components of the steer-by-wire steering assembly 100.

[0157] In some examples, the steer-by-wire steering assembly 100 may comprise additional features and components that further enhance the functionality and efficiency of the steer-by-wire steering assembly 100. These optional features may include various locking mechanisms, dual functionality components, and other elements that contribute to the reduction of size and complexity in the steering assembly 100.

[0158] The engagement between the rotary sensor target 242 and the rotor carrier sleeve 216 via their respective target threaded portion 4316 and sleeve inner threaded portion 4302 provides a locking engagement. This locking engagement secures the rotary sensor target 242 to the rotor carrier sleeve 216 and serves to fix the screw actuator 232 with respect to the rotor carrier sleeve 216. This dual functionality of the rotary sensor target 242 as both a sensor target and a locking nut for the screw actuator 232 helps reduce the overall size and complexity of the steering assembly 100.

[0159] In some examples, alternative locking mechanisms may be employed to secure the screw actuator 232 within the end cup formation 4300 of the rotor carrier sleeve 216. For instance, splines (not shown) on the outer surface of the end cup formation 4300 may be used to engage with corresponding splines on the screw actuator 232. Alternatively, a press fit or a threaded insert may be used to secure the screw actuator 232 within the end cup formation 4300.

[0160] Motor assembly connector

[0161] In one example, the motor assembly 206 of the steer-by-wire steering assembly 100 comprises a first motor 208 and a second motor 210, both mounted within the housing 102. The first motor 208 includes a first stator 212 and a first rotor 214, while the second motor 210 includes a second stator 218 and a second rotor 220. The motor assembly 206 may be designed to provide precise and efficient control of the steering shaft 118 movement, ensuring smooth and accurate steering performance.

[0162] In one example, the motor assembly connector 2300 is designed to provide both mechanical and electrical connections between the first stator 212 and the second stator 218 of the motor assembly 206. This configuration simplifies the assembly process and ensures proper alignment and secure connections between the stators. The motor assembly connector 2300 may comprise various features and components to facilitate these connections, as described in the following subsections.

[0163] In some examples, the motor assembly connector 2300 includes a connector body 2302 mounted between the first stator 212 and the second stator 218. The connector body 2302 may be made of metal or rigid plastic, ensuring high strength and durability. The use of such materials provides a robust and reliable connection between the motor stators, which is for the proper functioning of the steer-by-wire steering assembly 100. In one example, the motor assembly connector 2300 comprises at least one assembly window 2304 that exposes one or more stator terminals from the first stator 212 or the second stator 218 for soldering or welding. The assembly windows 2304 are positioned on the connector body 2302 and aligned with the stator terminals, facilitating easy access for the soldering or welding process. This design ensures secure electrical connections between the motor stators and the connector, reducing the risk of loose connections or disconnections and increasing the overall efficiency and reliability of the system.

[0164] In some examples, the motor assembly connector 2300 may comprise at least one temperature sensor configured to monitor the temperature between the first stator 212 and / or the second stator 218. The temperature sensors are aligned with the space between the stator coils, providing accurate temperature readings and ensuring safe operation and preventing overheating of the motor stators.

[0165] In one example, the motor assembly connector 2300 includes a first temperature sensor 2306 configured to detect the temperature of the first stator 212 and a second temperature sensor 2308 configured to detect the temperature of the second stator 218. These temperature sensors are integral with the motor assembly connector 2300 and connected to the first and second electronic control units (ECU) 200, 202, providing real-time temperature monitoring and control for the steer-by-wire steering assembly 100.

[0166] In some examples, the motor assembly connector 2300 may comprise at least one alignment tab 2310, 2312 configured to provide mechanical engagement between the motor assembly connector 2300 and the first stator 212 and the second stator 218. The alignment tabs ensure proper fit between the connector and motor stators, preventing incorrect assembly and maintaining proper alignment.

[0167] In one example, the alignment tabs include a first alignment tab 2310 mounted on the motor assembly connector 2300 and configured to align with a first tab recess on the first stator 212, and a second alignment tab 2312 mounted on the motor assembly connector 2300 and configured to align with a second tab recess on the second stator 218. The first alignment tab 2310 may have a different shape and / or orientation than the second alignment tab 2312, ensuring that the first stator 212, the second stator 218, and the motor assembly connector 2300 only fit together in one orientation. This arrangement simplifies the assembly process and reduces the risk of incorrect assembly or misalignment.

[0168] Overall, the motor assembly connector 2300 and its components play a role in the proper functioning of the steer-by-wire steering assembly 100. The connector ensures proper alignment, secure connections, and efficient operation of the system, while also providing additional features such as temperature monitoring and mechanical engagement. These features contribute to the overall reliability, safety, and performance of the steer-by-wire steering assembly 100.

[0169] In one example, the steer-by-wire steering assembly 100 includes electrical connection tracks 2320 that facilitate the transfer of electrical signals and power between various components of the assembly. The electrical connection tracks 2320 are best shown in Figure 4. These electrical connection tracks 2320 are designed to provide efficient and reliable communication between the motor assembly 206, the motor assembly connector 2300, and the electronic control units (ECUs) 200, 202.

[0170] In one example as shown in Figure 4, the motor assembly connector 2300 includes separate connector first stator terminals 2316 configured to respectively connect to different terminals of the first stator 212. This configuration ensures proper electrical connections between the first stator 212 and the motor assembly connector 2300, reducing the risk of loose connections or disconnections. Furthermore, the motor assembly connector 2300 includes separate connector second stator terminals 2318 configured to respectively connect to different terminals of the second stator 218. This configuration ensures proper electrical connections between the second stator 218 and the motor assembly connector 2300, reducing the risk of loose connections or disconnections.

[0171] In some examples, the motor assembly connector 2300 comprises electrical connection tracks 2320 that are configured to electrically connect each terminal of the first stator 212 and the second stator 218 to the first ECU 200 and / or the second ECU 202. The electrical connection tracks 2320 may be arranged in a specific configuration to ensure proper alignment and connection between the stator terminals and the ECUs. This configuration may be designed to minimise the length of connecting wires and reduce the potential for interference signals, thereby improving the overall efficiency and reliability of the electrical connections within the steer-by-wire steering assembly 100.

[0172] In some examples, the electrical connection tracks 2320 are printed tracks. The use of printed tracks offers several advantages over traditional wire connections. For instance, printed tracks can eliminate the need for additional wires or connectors, which can reduce the risk of loose connections or disconnections. Printed tracks also provide a more compact and streamlined design, allowing for a smaller and lighter steer-by-wire steering assembly 100.

[0173] Furthermore, printed tracks can increase the overall efficiency and reliability of the system by simplifying the electrical connections between terminal points. This simplification can reduce the likelihood of errors during assembly and operation, as well as decrease the time and effort required for assembly and maintenance.

[0174] In addition to these advantages, the use of printed tracks in the motor assembly connector 2300 may also allow for easier integration of other optional features, such as temperature sensors, alignment tabs, and assembly windows 2304. For example, the motor assembly connector 2300 may comprise at least one temperature sensor configured to monitor the temperature between the first stator 212 and / or the second stator 218. The temperature sensor may be integrated with the printed tracks, providing accurate temperature readings and ensuring safe operation of the steer-by-wire steering assembly 100.

[0175] In some examples, the motor assembly 206 can be assembled separately from the steer-by-wire steering assembly 100. This separate assembly can provide various advantages, such as simplifying the overall assembly process, reducing the risk of damage to the components during assembly, and allowing for easier maintenance and replacement of individual components. In one example as shown in Figure 4, the motor assembly 206 may comprise a cage 2314 or frame configured to hold the motor assembly connector 2300 in place with respect to the first and second stators 212, 218. The cage 2314 can provide additional support and stability to the motor assembly 206, ensuring proper alignment and secure connection between the first and second stators 212, 218 and the motor assembly connector 2300. The cage 2314 may be configured to mechanically engage the first and second stators 212, 218 and may surround the first stator 212 and the second stator 218. In some examples, the cage 2314 may comprise a plurality of rails extending parallel to the longitudinal axis 104 and mounted to the connector body 2302.

[0176] In one example, the method of assembling a steer-by-wire steering assembly 100 involves several steps to ensure proper alignment, secure connections, and efficient operation of the system. The method includes aligning and inserting the motor assembly connector 2300, soldering, or welding stator terminals, assembling the motor assembly 206, and mounting it in the housing 102.

[0177] In some examples, the first step of the assembly process involves aligning the first stator 212 and the second stator 218 with the motor assembly connector 2300. This alignment simplifies the assembly process and ensures proper positioning of the stators and the connector. Once the stators and the connector are aligned, the motor assembly connector 2300 is inserted into reciprocal terminals of the first stator 212 and the second stator 218. This insertion reduces the length of connecting wires and potential for interference signals, providing a more efficient and reliable connection between the stators and the connector.

[0178] In some examples, the method includes soldering or welding the stator terminals to the connector terminals through the assembly windows 2304. The assembly windows 2304 expose one or more stator terminals from the first stator 212 or the second stator 218 for soldering or welding, ensuring secure electrical connections between the stators and the connector. This step also provides a more compact and streamlined design, eliminating the need for additional wires or connectors and reducing the risk of loose connections or disconnections. In some examples, the motor assembly connector 2300 contains not only the three motor terminals, but also the according neutral point of a star winding configuration of each motor.

[0179] In some examples, the motor assembly connector 2300 contains on or more switching components, for examples but not limited to relays, to connect or disconnect motor terminals and windings from each other or from the ECU.

[0180] In some examples, the motor assembly connector 2300 contains also electrical components like, current sensors or temperature sensos.

[0181] In some examples, the method includes assembling the first stator 212, the second stator 218, and the motor assembly connector 2300 as a motor assembly 206. This assembly provides a rigid and stable subassembly for easy mounting in the housing 102. The motor assembly 206 may comprise additional components, such as temperature sensors, alignment tabs, and electrical connection tracks 2320, which further enhance the functionality and efficiency of the steer-by-wire steering assembly 100.

[0182] Once the motor assembly 206 is assembled, it is mounted into the housing 102 of the steer-by-wire steering assembly 100. This mounting ensures proper alignment and secure connections between the various components of the system, providing a robust and reliable steer-by-wire steering assembly 100.

[0183] In some examples, the first motor 208 and the second motor 210 may be assembled separately from the steer-by-wire steering assembly 100. This separate assembly allows for easier maintenance and replacement of individual components, as well as increased flexibility in the overall design and configuration of the steer-by-wire steering assembly 100.

[0184] Overall, the method of assembling the steer-by-wire steering assembly 100 provides a streamlined and efficient process for constructing a reliable and high-performance steering system. The various components and steps involved in the assembly process ensure proper alignment, secure connections, and optimal functionality of the steer- by-wire steering assembly 100, resulting in a robust and dependable steering solution for various vehicle applications.

[0185] Alternative linear displacement sensor assembly

[0186] As shown in Figures 14 and 15a, in some examples, the linear displacement sensor length 1302 is less than the threaded portion length 1300. This reduced size of the linear displacement sensor 244 provides several advantages, such as eliminating the need for a long linear sensor, reducing the overall size of the housing 102, and the steer-by-wire steering assembly 100. The linear displacement target 246 is configured to move between different positions along the linear displacement sensor length 1302, allowing the linear displacement sensor 244 to accurately detect the linear movement of the steering shaft 118 with respect to the housing 102 in a direction parallel with the longitudinal axis 104. Additionally, or alternatively, the linear displacement sensor 244 is configured to accurately detect the linear position of the steering shaft 118 with respect to the housing 102 along the longitudinal axis 104.

[0187] In one example, the position of the linear displacement target 246 with respect to the linear displacement sensor 244 corresponds to a unique position of the steering shaft 118. This configuration ensures that the linear displacement sensor assembly 238 can accurately detect the position of the steering shaft 118 at any point along its movement, providing precise control and feedback for the steer-by-wire steering assembly 100.

[0188] In some examples, the linear displacement sensor assembly 238 may comprise a guide pin 1304 coupled to the linear displacement target 246 and configured to follow a target guide track 1306. The interaction between the guide pin 1304 and the target guide track 1306 enables the linear displacement target 246 to move accurately along the linear displacement sensor length 1302, ensuring precise detection of the position of the steering shaft 118.

[0189] In one example, the target guide track 1306 is spiral and has a length equal to the threaded portion length 1300. This spiral configuration of the target guide track 1306 provides several advantages, such as allowing for a reduced linear sensor size while maintaining accurate and absolute position measurement of the steering shaft 118. The spiral target guide track 1306 can be wrapped circumferentially around the steering shaft 118 and mounted on a guide sleeve 1308 as shown in Figure 14, or it can be located in a radial disc 1310 projecting circumferentially from the steering shaft 118 and mounted on a rotor carrier sleeve 216 e.g., as shown in Figure 15a. The guide sleeve 1308 as shown in Figure 3 is mounted on the rotor carrier sleeve 216.

[0190] In some examples, the guide pin 1304 is configured to move the linear displacement target 246 along the target guide track 1306 when the target guide track 1306 moves with respect to the guide pin 1304. This configuration ensures that the linear displacement target 246 accurately follows the movement of the steering shaft 118, allowing the linear displacement sensor 244 to precisely detect the position of the steering shaft 118 along its movement.

[0191] The guide pin 1304 and spiral target guide track 1306 interaction provides a compact and efficient solution for detecting the linear movement of the steering shaft 118 in the steer-by-wire steering assembly 100. This design allows for a smaller linear sensor that accurately measures the position of the steering shaft 118 without requiring the full stroke length, reducing the overall size of the housing 102 and the steer-by-wire steering assembly 100.

[0192] In some examples, the steer-by-wire steering assembly 100 may comprise alternative configurations of the linear displacement sensor assembly 238 to provide additional flexibility and adaptability to various applications and requirements. These alternative configurations may include different mounting options for the guide sleeve 1308 and radial disc 1310, as well as variations in the target guide track 1306 and guide pin 1304 movement.

[0193] In one example, the spiral target guide track 1306 may be wrapped circumferentially around the steering shaft 118 and mounted on a guide sleeve 1308 mounted on the rotor carrier sleeve 216. The guide sleeve 1308 may be configured to securely hold the target guide track 1306 in place while allowing for smooth and precise movement of the guide pin 1304 along the track. This configuration may provide a compact and efficient design for the linear displacement sensor assembly 238, as the guide sleeve 1308 may be easily integrated into the overall structure of the steer-by-wire steering assembly 100. In some examples, the rotor carrier sleeve 216 is extended to incorporate the guide sleeve 1308 mounted on the rotor carrier sleeve 216.

[0194] In another example as shown in Figures 15a and 15b, the spiral target guide track 1306 may be located in a radial disc 1310 projecting circumferentially from the steering shaft 118 and mounted on the rotor carrier sleeve 216. The radial disc 1310 may provide a stable and robust platform for the target guide track 1306, ensuring accurate and reliable movement of the guide pin 1304 along the track. This configuration may offer increased durability and resistance to external forces or vibrations, which may be particularly advantageous in high-performance or heavy-duty applications.

[0195] In some examples, the target guide track 1306 and guide pin 1304 may be configured to interact in various ways to achieve the desired movement of the linear displacement target 246 along the linear displacement sensor length 1302. For instance, the guide pin 1304 may be configured to move the linear displacement target 246 along the target guide track 1306 when the target guide track 1306 moves with respect to the guide pin 1304. This configuration may provide a direct and efficient means of translating the movement of the steering shaft 118 into the movement of the linear displacement target 246, ensuring accurate and responsive detection of the position of the steering shaft 118 by the linear displacement sensor 244.

[0196] In some examples, the target guide track 1306 may comprise additional features or modifications to further enhance the performance and functionality of the linear displacement sensor assembly 238. For instance, the target guide track 1306 may comprise multiple parallel tracks or channels, allowing for the guide pin 1304 to switch between different paths and provide redundancy or increased resolution in the detection of the position of the steering shaft 118. Alternatively, the target guide track 1306 may comprise variable pitch or curvature, enabling the linear displacement sensor assembly 238 to adapt to different steering shaft 118 movement profiles or operating conditions.

[0197] In some examples the ratio of the threaded portion length 1300 to the linear displacement sensor length 1302 is 8:1. In other examples the ratio of the threaded portion length 1300 to the linear displacement sensor length 1302 is 7:1 , 6:1 , 5:1 , 4:1 , 3:1 , 2:1 of any other suitable ratio to reduce the overall length of the linear displacement sensor length 1302.

[0198] In some examples, the spiral guide track 1306 mounted on the radial disc 1310 can be configured to be the rotary sensor target 242 of the rotational sensor assembly 236. This means that the spiral guide track 1306 can be dual purpose and used for both the rotational sensor assembly 236 and the linear displacement sensor assembly 238.

[0199] Overall, these alternative configurations of the linear displacement sensor assembly 238 may provide additional design options and flexibility for the steer-by-wire steering assembly 100, allowing it to be tailored to specific applications and requirements while maintaining the advantages of the reduced size and accurate position measurement provided by the linear displacement sensor 244.

[0200] Motor winding redundancy

[0201] In one example, the motor assembly 206 of the steer-by-wire steering assembly 100 comprises a first motor 208 and a second motor 210, both mounted within the housing 102. The first motor 208 includes a first stator 212 and a first rotor 214, while the second motor 210 includes a second stator 218 and a second rotor 220. The motor assembly 206 may be designed to provide precise and efficient control of the steering shaft 118 movement, ensuring smooth and accurate steering performance.

[0202] As shown in Figure 3, the steer-by-wire steering assembly 100 comprises a motor assembly 206, which includes a first motor 208 and a second motor 210. In one example, the first motor 208 has a first plurality of motor windings 3312, and the second motor 210 has a second plurality of motor windings 3314. The first and second plurality of motor windings 3312, 3314 are arranged in a specific phase arrangement to enable efficient and reliable operation of the steer-by-wire steering assembly 100.

[0203] In some examples, the first plurality of motor windings 3312 of the first motor 208 and the second plurality of motor windings 3314 of the second motor 210 each comprise at least three phase windings. These phase windings are arranged at different angular positions to ensure proper functioning and distribution of torque during the operation of the steer-by-wire steering assembly 100. The arrangement of the first and second plurality of motor windings 3312, 3314 in the first and second motors 208, 210 allows for the generation of a rotating magnetic field, which in turn drives the rotors of the motors and ultimately the rotor carrier sleeve 216.

[0204] In one example, as shown schematically in Figure 3, the first plurality of motor windings 3312 comprises a first phase winding 3300 arranged at 0 degrees, a second phase winding 3302 arranged at 120 degrees, and a third phase winding 3304 arranged at 240 degrees. Similarly, the second plurality of motor windings 3314 comprises a first phase winding 3306 arranged at 0 degrees, a second phase winding 3308 arranged at 120 degrees, and a third phase winding 3310 arranged at 240 degrees. This arrangement of phase windings in both the first and second plurality of motor windings 3312, 3314 ensures that the magnetic fields generated by the motors are properly aligned and synchronised, allowing for smooth and efficient operation of the steer-by- wire steering assembly 100.

[0205] The phase arrangement of the motor windings 3300, 3302, 3304, 3306, 3308, 3310 may also comprise more than three phases, such as four phases, five phases, or six phases, depending on the specific requirements and design of the steer-by-wire steering assembly 100. The use of additional phases can provide increased torque and power output, as well as improved fault tolerance and redundancy in the event of a fault in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310.

[0206] As mentioned above, the steer-by-wire steering assembly 100 may comprise a first ECU 200, a second ECU 202 and / or a VCU 204. Any of these control units 200, 202, 204 can perform the operation as described. Hereinafter the term "controller" 200 will be used but can refer to any of the first ECU 200, the second ECU 202 and I or the VCU 204. The controller 200, which is connected to the first plurality of motor windings 3312 of the first motor 208 and the second plurality of motor windings 3314 of the second motor 210, is configured to detect faults in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310 in both the first and second plurality of motor windings 3312, 3314. In the event of a fault in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310, the controller 200 can selectively energise corresponding fault-free windings in the other set of windings, allowing the faulty first motor 208 and the faulty second motor 210 to operate together to rotate the rotor carrier sleeve 216. This fault detection and selective energising feature of the controller 200 provides several advantages for the steer-by-wire steering assembly 100. First, it allows for continued operation of the assembly even in the presence of faults in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310, ensuring that the steering functionality is maintained and preventing potential safety hazards. Second, it enables the controller 200 to deenergise the faulting windings, preventing further damage to the first motor 208 and / or the second motor 210. Finally, the selective energising of fault-free windings allows for the efficient use of the available motor windings 3300, 3302, 3304, 3306, 3308, 3310, ensuring that the steer-by-wire steering assembly 100 operates at optimal performance levels even in the presence of faults.

[0207] The steer-by-wire steering assembly 100 includes a controller 200 that plays a role in the operation and functionality of the assembly. In one example, the controller 200 is connected to the first plurality of motor windings 3312 of the first motor 208 and the second plurality of motor windings 3314 of the second motor 210. The controller 200 is responsible for detecting faults in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310 in the first plurality of motor windings 3312 and the second plurality of motor windings 3314 and selectively energising corresponding fault-free windings in the other set of windings.

[0208] In some examples, the controller 200 is configured to detect faults in the motor windings 3300, 3302, 3304, 3306, 3308, 3310 by monitoring various parameters, such as abnormal current flow, voltage drop, overheating, open circuit, and phase imbalance. By monitoring these parameters, the controller 200 can identify potential issues in the motor windings 3300, 3302, 3304, 3306, 3308, 3310 and take appropriate action to maintain the functionality of the steer-by-wire steering assembly 100. This provides the advantage of accurately detecting various types of faults in the motor windings.

[0209] In one example, the controller 200 monitors the current flow in each motor winding 3300, 3302, 3304, 3306, 3308, 3310 and detects when there is an abnormal current flow in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310, indicating a possible short circuit fault. In another example, the controller 200 monitors the voltage across each motor winding 3300, 3302, 3304, 3306, 3308, 3310 and detects when there is a significant voltage drop, indicating a potentially faulty winding. In yet another example, the controller 200 measures the temperature of each motor winding 3300, 3302, 3304, 3306, 3308, 3310 and detects when a winding exceeds a certain threshold, indicating an overheating fault. In some examples, the controller 200 checks for a lack of continuity in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310, indicating an open circuit fault. In other examples, the controller 200 analyses the current flowing through each motor winding 3300, 3302, 3304, 3306, 3308, 3310 and detects when there is an imbalance, indicating a potential phase imbalance fault.

[0210] In some examples, the controller 200 is configured to deenergise the faulting windings to prevent further damage to the first motor 208 and / or the second motor 210. By deenergising the faulting windings, the controller 200 can help protect the motors from further damage and maintain the overall functionality of the steer-by-wire steering assembly 100.

[0211] In addition to detecting faults and deenergising faulting windings, the controller 200 may also selectively energise fault-free windings in the first plurality of motor windings 3312 and the second plurality of motor windings 3314. This selective energising allows the controller 200 to operate the faulty first motor 208 and the faulty second motor 210 together to rotate the rotor carrier sleeve 216, ensuring that the steer-by-wire steering assembly 100 continues to function even in the presence of faults in one or both motors.

[0212] The controller 200 may also be configured to continuously monitor the windings of both the first motor 208 and the second motor 210 and selectively energise fault-free windings as necessary to maintain the functionality of the steer-by-wire steering assembly 100. This continuous monitoring and selective energising of fault-free windings help ensure that the assembly 100 remains operational even when faults are present in the motor windings 3300, 3302, 3304, 3306, 3308, 3310, providing a more robust and reliable steer-by-wire steering system.

[0213] The method of operating the steer-by-wire steering assembly 100 involves a series of steps and processes that ensure the efficient and reliable functioning of the assembly, even in the presence of faults in the motor windings 3300, 3302, 3304, 3306, 3308, 3310. In one example, the method includes detecting if there is a fault in the windings of the first motor 208, checking if there is a fault in the windings of the second motor 210 if a fault is detected in the first motor 208, selectively energising a functional winding on the first motor 208 or the second motor 210 that corresponds to the faulting winding on the other motor, and operating the faulty first motor 208 and the faulty second motor 210 together to rotate the rotor carrier sleeve 216. The method may also include continuously monitoring the windings of both motors and selectively energising fault-free windings as necessary to maintain the functionality of the steer-by-wire steering assembly 100.

[0214] In some examples, the method begins with the detection of faults in the windings of the first motor 208. The controller 200 is configured to detect faults in one or more motor windings 3300, 3302, 3304, 3306, 3308, 3310 in the first plurality of motor windings 3312 and the second plurality of motor windings 3314. The controller 200 may employ various fault detection methods, such as monitoring abnormal current flow, voltage drop, overheating, open circuit, and phase imbalance. These methods help identify potential issues in the motor windings 3300, 3302, 3304, 3306, 3308, 3310, allowing for timely intervention and corrective action.

[0215] If a fault is detected in the windings of the first motor 208, the method proceeds to check if there is a fault in the windings of the second motor 210. This step ensures that the controller 200 has a comprehensive understanding of the current state of both motors, allowing for more informed decision-making regarding the selective energising of functional windings.

[0216] In the event that faults are detected in the windings of both the first motor 208 and the second motor 210, the controller 200 selectively energises a functional winding on the first motor 208 or the second motor 210 that corresponds to the faulting winding on the other motor. This selective energising process allows the steer-by-wire steering assembly 100 to continue functioning despite the presence of faults in the motor windings 3300, 3302, 3304, 3306, 3308, 3310. By leveraging the fault-free windings in the first plurality of motor windings 3312 and the second plurality of motor windings 3314, the controller 200 can ensure that each different phase can be energised, maintaining the functionality of the assembly.

[0217] Once the functional windings have been selectively energised, the controller 200 operates the faulty first motor 208 and the faulty second motor 210 together to rotate the rotor carrier sleeve 216. For example, the controller 200 may detect that the first phase winding 3300 of the first motor 208 is faulty. In this case the controller 200 will energise the first phase winding 3306 of the second motor 210 instead of the first phase winding 3300 of the first motor 208. This means that the first phase winding 3306 of the second motor 210 performs the function of the first phase winding 3300 of the first motor 208. This provides the advantage of maintaining the functionality of the steering assembly even when faults are detected in both the first plurality of motor windings 3312 and the second plurality of motor windings 3314.

[0218] Furthermore, the controller 200 may yet detect more faults e.g., the controller 200 may detect that the second phase winding 3308 of the second motor 210 is also faulty. In this case the controller 200 will energise the second phase winding 3302 of the first motor 208 instead of the second phase winding 3308 of the second motor 210. This means that the second phase winding 3302 of the first motor 208 performs the function of the second phase winding 3308 of the second motor 210.

[0219] The controller 200 can detect and selectively energise fault-free motor windings corresponding to the same phase as many times as needed. This may be important since multiple motor windings failing may be indicative of a major failure but selecting energising fault-free motor windings in order to continue to operate the steer-by-wire steering assembly 100 ensures a fail operational state such that the vehicle can be safely driven to a suitable location for maintenance. This coordinated operation of the faulty motors allows the steer-by-wire steering assembly 100 to continue functioning despite the presence of faults in the motor windings. The ability to operate faulty motors together provides a significant advantage in terms of reliability and resilience, ensuring that the assembly can continue to function even in the presence of faults. In some examples, the method may also include continuously monitoring the windings of both the first motor 208 and the second motor 210 and selectively energising fault- free windings as necessary to maintain the functionality of the steer-by-wire steering assembly 100. This continuous monitoring process allows the controller 200 to detect any new faults that may arise during operation and take appropriate corrective action by selectively energising the corresponding fault-free windings.

[0220] Additionally, the controller 200 may be configured to deenergise the faulting windings to prevent further damage to the first motor 208 and / or the second motor 210. This proactive approach to fault management helps protect the motors from further damage and prolongs the overall lifespan of the steer-by-wire steering assembly 100.

[0221] Accordingly, the controller 200 is configured to detect a fault in one or more motor windings 3300, 3302, 3304 in the first plurality of motor windings 3312 and a fault in the one or more windings 3306, 3308, 3310 in the second plurality of motor windings (3314). The controller 200 is then configured to selectively energise corresponding fault-free windings respectively in the one or more windings 3306, 3308, 3310 in the second plurality of motor windings 3314 and in one or more motor windings 3300, 3302, 3304 in the first plurality of motor windings 3312. This means that the controller 200 is configured to operate the first plurality of motor windings 3312 having a first faulty winding and the second plurality of motor windings 3314 having a second faulty winding together to rotate the rotor carrier sleeve (216).

[0222] In summary, the method of operating the steer-by-wire steering assembly 100 provides a robust and reliable approach to managing faults in the motor windings. By detecting faults, selectively energising functional windings, operating faulty motors together, and continuously monitoring the windings, the assembly can maintain its functionality and ensure a high level of performance even in the presence of faults.

[0223] Examples

[0224] First set of examples

[0225] Example 1 . A steer-by-wire steering assembly (100) comprising: a housing (102); a motor assembly (206) comprising at least one motor (208) mounted in the housing (102); a screw actuator (232) configured to engage with a threaded portion (234) of a steering shaft (118) and move the steering shaft (118) along a longitudinal axis (104) when the screw actuator (232) rotates; a rotor carrier sleeve (216) operatively 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) comprising a sensor portion (244) and a 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) are mounted in a sensor housing (316) fixed with respect to the steering shaft (118); and the housing (102) comprises a sensor channel (302) configured to receive the sensor housing (316) and constrain the movement of a sensor housing (316) and the steering shaft (118) in a direction parallel to the longitudinal axis (104).

[0226] Example 2. The steer-by-wire steering assembly (100) according to example 1 , wherein the sensor assembly (238) is a linear displacement sensor assembly (238).

[0227] Example 3. The steer-by-wire steering assembly (100) according to example 1 or 2, wherein the sensor housing (316) is configured to slide within the sensor channel (302).

[0228] Example 4. The steer-by-wire steering assembly (100) according to any one of examples 1 to 3, wherein the sensor channel (302) is located within a housing sleeve portion (300) of the housing (102).

[0229] Example s. The steer-by-wire steering assembly (100) according to example 4, further comprising a mounting assembly (306) fixed to the housing sleeve portion (300) and comprising at least one elongate rail (308) defining the sensor channel (302). Example 6. The steer-by-wire steering assembly (100) according to example 5, wherein the mounting assembly (306) further comprises fasteners (310) configured to clamp the at least one elongate rails (308) to an inner surface of the housing sleeve portion (300).

[0230] Example 7. The steer-by-wire steering assembly (100) according to any one of examples 1 to 6, wherein the sensor housing (316) comprises a shaft engagement sleeve (320) configured to mount around the steering shaft (118).

[0231] Example s. The steer-by-wire steering assembly (100) according to example 7, wherein the shaft engagement sleeve (320) comprises a central bore (322) configured to receive the steering shaft (118).

[0232] Example 9. The steer-by-wire steering assembly (100) according to any one of examples 1 to 8, wherein the sensor housing (316) comprises a first housing engagement surface (318) and a second housing engagement surface (326) configured to engage respectively with first channel and second channel engagement surfaces (304, 324) of the sensor channel (302).

[0233] Example 10. The steer-by-wire steering assembly (100) according to example 9, wherein the sensor channel (302) comprises a first channel engagement surface (304) configured to engage the first housing engagement surface (318) when the screw actuator (232) rotates in a first direction, and a second channel engagement surface (324) configured to engage the second housing engagement surface (326) when the screw actuator (232) rotates in a second direction.

[0234] Example 11. The steer-by-wire steering assembly (100) according to any one of examples 1 to 10, wherein the sensor housing (316) is mounted on the steering shaft (118) using a set screw, press fit, or welding.

[0235] Example 12. The steer-by-wire steering assembly (100) according to any one of examples 1 to 11 , further comprising a second sensor assembly (500) comprising a second sensor portion (244b) and a second target portion (246b) configured to detect relative movement of the steering shaft (118) with respect to the housing (102). Example 13. The steer-by-wire steering assembly (100) according to example 12, wherein the second sensor assembly (500) is a linear displacement sensor assembly (238).

[0236] Example 14. The steer-by-wire steering assembly (100) according to example 12 or 13, wherein one of the second sensor portion (244b) and the second target portion (246b) are mounted in a second sensor housing (502) fixed with respect to the steering shaft (118).

[0237] Example 15. The steer-by-wire steering assembly (100) according to example 14, wherein the second sensor housing (502) is configured to slide within a second sensor channel (302) in the housing (102).

[0238] Example 16. The steer-by-wire steering assembly (100) according to any one of examples 12 to 15, wherein the first and second sensor assemblies (238,500) are mounted at different positions on the steering shaft (118).

[0239] Example 17. The steer-by-wire steering assembly (100) according to any one of examples 1 to 16, wherein the motor assembly (206) comprises a first motor (208) and a second motor (210), and the rotor carrier sleeve (216) is operatively coupled between the first motor (208), the second motor (210), and the screw actuator (232).

[0240] Second set of examples

[0241] Example 1 . A steer-by-wire steering assembly (100) comprising: a housing (102); a motor assembly (206) comprising at least one motor (208) mounted in the housing (102); a screw actuator (232) configured to engage with a threaded portion (234) of a steering shaft (118) and move the steering shaft (118) along a longitudinal axis (104) when the screw actuator (232) rotates; a rotor carrier sleeve (216) operatively coupled between the at least one motor (208) and the screw actuator (232) and configured to rotate about the longitudinal axis (104); and a rotational sensor assembly (236) comprises a rotary sensor target (242) and a rotary sensor (240) configured to detect relative rotational movement of the rotary sensor target (242); wherein the rotary sensor target (242) is configured to mount on the rotor carrier sleeve (216) and fix the screw actuator (232) with respect to the rotor carrier sleeve (216).

[0242] Example 2. The steer-by-wire steering assembly (100) according to example 1 wherein the rotor carrier sleeve (216) comprises an end cup formation (4300) configured to receive the screw actuator (232).

[0243] Example s. The steer-by-wire steering assembly (100) according to example 2, wherein the end cup formation (4300) comprises a sleeve inner threaded portion (4302) configured to engage with the rotary sensor target (242).

[0244] Example 4. The steer-by-wire steering assembly (100) according to example 3, wherein the rotary sensor target (242) comprises a target threaded portion (4316) configured to engage with the sleeve inner threaded portion (4302) of the rotor carrier sleeve (216).

[0245] Example s. The steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the screw actuator (232) is a ball screw nut (232) mounted within the end cup formation (4300).

[0246] Example 6. The steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the rotor carrier sleeve (216) further comprises a key slot (4306) configured to receive a separate key element (4312).

[0247] Example 7. The steer-by-wire steering assembly (100) according to example 6, wherein the key element (4312) is configured to engage an internal surface of an outer bearing (4314) and align and maintain the position of the rotor carrier sleeve (216) with respect to the outer bearing (4314).

[0248] Example s. The steer-by-wire steering assembly (100) according to example 7, wherein the key element (4312) is configured to engage the screw actuator (232) and keep the screw actuator (232), the rotor carrier sleeve (216), and the outer bearing (4314) fixed with respect to each other.

[0249] Example 9. The steer-by-wire steering assembly (100) according to example 1 , wherein the motor assembly (206) comprises a first motor (208) and a second motor (210).

[0250] Example 10. The steer-by-wire steering assembly (100) according to example 9, wherein the first motor (208) comprises a first rotor (214) and a first stator (212), and the second motor (210) comprises a second rotor (220) and a second stator (218).

[0251] Example 11. The steer-by-wire steering assembly (100) according to example 1 , wherein the rotary sensor (240) is selected from one or more of an optical rotary sensor, a magnetic rotary sensor, a capacitive rotary sensor, an inductive rotary sensor, a Hall effect rotary sensor, and a resolver.

[0252] Example 12. The steer-by-wire steering assembly (100) according to example 2, wherein the screw actuator (232) is mounted in the same radial plane (4318) as an outer bearing (4314) and the end cup formation (4300).

[0253] Example 13. The steer-by-wire steering assembly (100) according to example 12, wherein the screw actuator (232) is a ball screw nut (232) that has a reduced length from 10 to 6 complete revolutions of engaging ball bearings.

[0254] Example 14. The steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the rotor carrier sleeve (216) further comprises a sleeve outer threaded portion (4304) configured to engage with an outer locking nut (4310). Example 15. The steer-by-wire steering assembly (100) according to example 14, wherein the outer locking nut (4310) is configured to clamp the rotor carrier sleeve (216) to the outer bearing (4314).

[0255] Example 16. The steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the rotary sensor target (242) is configured to lock the ball screw nut (232) in place within the end cup formation (4300).

[0256] Example 17. The steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the end cup formation (4300) comprises a cup shoulder portion (4308) configured to abut and position the outer bearing (4314).

[0257] Third set of examples

[0258] Example 1 . A steer-by-wire steering assembly (100) comprising: a housing (102); a motor assembly (206) mounted in the housing (102) comprising a first motor (208) having a first stator (212) and a first rotor (214), and a second motor (210) having a second stator (218) and a second rotor (220); a screw actuator (232) configured to engage with a threaded portion (234) of a steering shaft (118) and move the steering shaft (118) along a longitudinal axis (104) when the screw actuator (232) rotates; a rotor carrier sleeve (216) operatively coupled between the first rotor (214) and the second rotor (220) and the screw actuator (232); and a motor assembly connector (2300) configured to provide mechanical connection and electrical connection to both the first motor (208) and the second motor (210).

[0259] Example 2. The steer-by-wire steering assembly (100) according to example 1 , wherein the motor assembly connector (2300) comprises a connector body (2302) mounted between the first stator (212) and the second stator (218).

[0260] Example s. The steer-by-wire steering assembly (100) according to example 2, wherein the connector body (2302) is made of metal or rigid plastic. Example 4. The steer-by-wire steering assembly (100) according to any one of examples 1 to 3, wherein the motor assembly connector (2300) comprises at least one assembly window (2304) exposing one or more stator terminals from the first stator (212) or the second stator (218) for soldering or welding.

[0261] Example s. The steer-by-wire steering assembly (100) according to any one of examples 1 to 4, wherein the motor assembly connector (2300) comprises at least one temperature sensor (2306, 2308) configured to monitor the temperature between the first stator (212) and the second stator (218).

[0262] Example 6. The steer-by-wire steering assembly (100) according to example 5, wherein the at least one temperature sensor (2306, 2308) comprises a first temperature sensor (2306) configured to detect the temperature of the first stator (212) and a second temperature sensor (2308) configured to detect the temperature of the second stator (218).

[0263] Example 7. The steer-by-wire steering assembly (100) according to any one of examples 1 to 6, wherein the motor assembly connector (2300) comprises at least one alignment tab (2310, 2312) configured to provide mechanical engagement between the motor assembly connector (2300) and the first stator (212) and the second stator (218).

[0264] Example s. The steer-by-wire steering assembly (100) according to example 7, wherein the alignment tabs (2310, 2312) comprise a first alignment tab (2310) mounted on the motor assembly connector (2300) and configured to align with a first tab recess on the first stator (212), and a second alignment tab (2312) mounted on the motor assembly connector (2300) and configured to align with a second tab recess on the second stator (218).

[0265] Example 9. The steer-by-wire steering assembly (100) according to example 8, wherein the first alignment tab (2310) has a different shape and / or orientation than the second alignment tab (2312). Example 10. The steer-by-wire steering assembly (100) according to any one of examples 1 to 9, wherein the motor assembly connector (2300) comprises electrical connection tracks (2320) configured to electrically connect each terminal of the first stator (212) and the second stator (218) to a first electronic control unit (ECU) (200) and / or a second ECU (202).

[0266] Example 11. The steer-by-wire steering assembly (100) according to example 10, wherein the electrical connection tracks (2320) are printed tracks.

[0267] Example 12. The steer-by-wire steering assembly (100) according to any one of examples 1 to 11 , further comprising a rotational sensor assembly (236) configured to detect relative rotational movement of the rotor carrier sleeve (216) or other rotating components (118) with respect to the housing (102).

[0268] Example 13. The steer-by-wire steering assembly (100) according to any one of examples 1 to 12, further comprising a linear displacement sensor assembly (238) configured to detect relative linear movement of the steering shaft (118) with respect to the housing (102).

[0269] Example 14. The steer-by-wire steering assembly (100) according to any one of examples 1 to 13, wherein the screw actuator (232) comprises a ball screw nut or a roller screw.

[0270] Example 15. The steer-by-wire steering assembly (100) according to any one of examples 1 to 14, wherein the first motor (208) and the second motor (210) can be assembled in the motor assembly (206) separately from the steer-by-wire steering assembly (100).

[0271] Example 16. A method of assembling a steer-by-wire steering assembly (100) according to any one of examples 1 to 15, comprising the steps of: aligning the first stator (212) and the second stator (218) with the motor assembly connector (2300); inserting the motor assembly connector (2300) into reciprocal terminals of the first stator (212) and the second stator (218); soldering or welding the stator terminals to the connector terminals through the assembly windows (2304); and assembling the first stator (212), the second stator (218), and the motor assembly connector (2300) as a motor assembly (206) mounting the motor assembly (206) into a housing (102) of the steer-by-wire steering assembly (100).

[0272] Example 17. A motor assembly (206) for a steer-by-wire steering assembly (100) comprising: a first motor (208) having a first stator (212) and a first rotor (214); a second motor (210) having a second stator (218) and a second rotor (220); and a motor assembly connector (2300) configured to provide mechanical connection and electrical connection to both the first motor (208) and the second motor (210).

[0273] Fourth set of examples

[0274] Example 1 . A steer-by-wire steering assembly (100) comprising: a housing (102); a motor assembly (206) comprising at least one motor (208) mounted in the housing (102); a screw actuator (232) configured to engage with a threaded portion (234) of a steering shaft (118) and move the steering shaft (118) along a longitudinal axis (104) when the screw actuator (232) rotates; wherein the threaded portion (234) has a threaded portion length (1300) along the longitudinal axis (104); and a linear displacement sensor assembly (238) having a linear displacement sensor (244) having a linear displacement sensor length (1302) and a linear displacement target (246) configured to follow movement of the steering shaft (118) and move between different positions along the linear displacement sensor length (1302) such that the linear displacement sensor (244) is configured to a detect linear position of the steering shaft (118) with respect to the housing (102) along the longitudinal axis (104), wherein the linear displacement sensor length (1302) is less than the threaded portion length (1300). Example 2. A steer-by-wire steering assembly (100) according to example 1 wherein the threaded portion length (1300) corresponds to the full stroke length of the steer- by-wire steering assembly (100).

[0275] Example s. A steer-by-wire steering assembly (100) according to any of the preceding examples wherein the position of the linear displacement target (246) with respect to the linear displacement sensor (244) when following movement of the steering shaft (118) corresponds to a unique position of the steering shaft (118).

[0276] Example 4. A steer-by-wire steering assembly (100) according to any of the preceding examples, further comprising a guide pin (1304) coupled to the linear displacement target (246) and configured to follow a target guide track (1306).

[0277] Example 5. A steer-by-wire steering assembly (100) according to example 4, wherein the target guide track (1306) is spiral and the target guide track (1306) is equal in length equal to the threaded portion length (1300).

[0278] Example 6. A steer-by-wire steering assembly (100) according to example 5, wherein the spiral target guide track (1306) is wrapped circumferentially around the steering shaft (118) and mounted on a guide sleeve (1308) mounted on a rotor carrier sleeve (216).

[0279] Example 7. A steer-by-wire steering assembly (100) according to example 5, wherein the spiral target guide track (1306) is located in a radial disc (1310) projecting circumferentially from the steering shaft (118) and mounted on a rotor carrier sleeve (216).

[0280] Example 8. A steer-by-wire steering assembly (100) according to any of examples 4 to 7, wherein the guide pin (1304) is configured to move the linear displacement target (246) along the target guide track (1306) when the target guide track (1306) moves with respect to the guide pin (1304). Example 9. A steer-by-wire steering assembly (100) according to any of the preceding examples wherein the linear displacement sensor (244) is fixed with respect to the housing (102).

[0281] Example 10. A steer-by-wire steering assembly (100) according to any of the preceding examples, further comprising a rotational sensor assembly (236) configured to detect relative rotational movement of the steering shaft (118) with respect to the housing (102).

[0282] Example 11. A steer-by-wire steering assembly (100) according to example 10, wherein the rotational sensor assembly (236) comprises a rotary sensor (240) and a rotary sensor target (242).

[0283] Example 12. A steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the motor assembly (206) comprises a first motor (208) and a second motor (210) mounted in the housing (102).

[0284] Example 13. A steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the screw actuator (232) comprises a ball screw nut or a roller screw.

[0285] Example 14. A steer-by-wire steering assembly (100) according to any of the preceding examples, further comprising a controller comprising a first electronic control unit (ECU) (200), a second ECU (202), a vehicle control unit (VCU) (204), and an ECU data connection (222).

[0286] Fifth set of examples

[0287] Example 1 . A steer-by-wire steering assembly (100) comprising: a housing (102); a motor assembly (206) comprises a first plurality of motor windings (3312) and a second plurality of motor windings (3314); a rotor carrier sleeve (216) operatively coupling the motor assembly (206) to a screw actuator (232) configured to engage with a threaded portion (234) of a steering shaft (118) and move the steering shaft (118) along a longitudinal axis (104) when the screw actuator (232) rotates; and a controller (200) connected to the first plurality of motor windings (3312) and the second plurality of motor windings (3314), the controller (200) being configured to detect a fault in one or more motor windings (3300, 3302, 3304,) in the first plurality of motor windings (3312) and a fault in the one or more windings (3306, 3308, 3310) in the second plurality of motor windings (3314), and to selectively energise corresponding fault-free windings in the other set of windings, wherein the controller (200) is configured to operate the first plurality of motor windings (3312) having a first faulty winding and the second plurality of motor windings (3314) having a second faulty winding together to rotate the rotor carrier sleeve (216).

[0288] Example 2. The steer-by-wire steering assembly (100) according to example 1 , wherein the motor assembly (206) comprises a first motor (208) having the first plurality of motor windings (3312) and a second motor (210) having the second plurality of motor windings (3314).

[0289] Example s. The steer-by-wire steering assembly (100) according to example 2, wherein the first motor (208) comprises a first rotor (214) and a first stator (212), and the second motor (210) comprises a second rotor (220) and a second stator (218).

[0290] Example 4. The steer-by-wire steering assembly (100) according to example 3, wherein the first rotor (214) and the second rotor (220) are mechanically coupled to the rotor carrier sleeve (216).

[0291] Example s. The steer-by-wire steering assembly (100) according to any one of examples 1 to 4, wherein the controller (200) is configured to deenergise the faulting windings in the first plurality of motor windings (3312) and the second plurality of motor windings (3314) to prevent further damage to the motor assembly (206).

[0292] Example 6. The steer-by-wire steering assembly (100) according to any one of examples 1 to 5, wherein the controller (200) is configured to detect faults in the motor windings (3300, 3302, 3304, 3306, 3308, 3310) based on at least one of abnormal current flow, voltage drop, overheating, open circuit, and phase imbalance. Example 7. The steer-by-wire steering assembly (100) according to any one of examples 1 to 6, wherein the screw actuator (232) is a ball screw or a roller screw.

[0293] Example s. The steer-by-wire steering assembly (100) according to any one of examples 1 to 7, wherein the steering shaft (118) is configured to move linearly along the longitudinal axis (104) when the screw actuator (232) rotates.

[0294] Example 9. The steer-by-wire steering assembly (100) according to any one of examples 1 to 8, the first plurality of motor windings (3312) and the second plurality of motor windings (3314) have the same motor winding arrangement.

[0295] Example 10. The steer-by-wire steering assembly (100) according to any one of examples 1 to 9, wherein the first plurality of motor windings (3312) and the second plurality of motor windings (3314) each comprise at least three phase windings arranged at different angles.

[0296] Example 11. The steer-by-wire steering assembly (100) according to example 10, wherein the first plurality of motor windings (3312) and the second plurality of motor windings (3314) each comprise more than three phase windings.

[0297] Example 12. The steer-by-wire steering assembly (100) according to any of the preceding examples, wherein the first plurality of motor windings (3312) and the second plurality of motor windings (3314) are mounted on the same stator (212).

[0298] Example 13. A method of operating a steer-by-wire steering assembly (100) according to any one of examples 1 to 12, the method comprising: detecting faults in one or more motor windings in the first plurality of motor windings (3312) and the second plurality of motor windings (3314) using the controller (200); selectively energising corresponding fault-free windings in the other set of windings; and operating the first plurality of motor windings (3312) having a first faulty winding and the second plurality of motor windings (3314) having a second faulty winding together to rotate the rotor carrier sleeve (216).

[0299] Example 14. The method according to example 13, further comprising deenergising the faulting windings in the first plurality of motor windings (3312) and the second plurality of motor windings (3314) to prevent further damage to the motor assembly (206).

[0300] Example 15. The method according to examples 13 or 14, wherein detecting faults in the motor windings (3300, 3302, 3304, 3306, 3308, 3310) comprises detecting faults based on at least one of abnormal current flow, voltage drop, overheating, open circuit, and phase imbalance.

[0301] Example 16. The method according to any one of examples 13 to 15, further comprising moving the steering shaft (118) linearly along the longitudinal axis (104) when the screw actuator (232) rotates.

[0302] Example 17. The method according to any one of examples 13 to 16, further comprising monitoring the windings of both the first plurality of motor windings (3312) and the second plurality of motor windings (3314) and selectively energising fault-free windings as necessary to maintain functionality of the steer-by-wire steering assembly (100).

[0303] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and / or groups thereof.

[0304] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element without departing from the scope of the present disclosure.

[0305] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe a relationship of one element to another element as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0306] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealised or overly formal sense unless expressly so defined herein.

[0307] It is to be understood that the present disclosure is not limited to the aspects described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and appended claims. In the drawings and specification, there have been disclosed aspects for purposes of illustration only and not for purposes of limitation, the scope of the disclosure being set forth in the following claims.

Claims

Claims1 . A steer-by-wire steering assembly (100) comprising: a housing (102); a motor assembly (206) comprising at least one motor (208) mounted in the housing (102); a screw actuator (232) configured to engage with a threaded portion (234) of a steering shaft (118) and move the steering shaft (118) along a longitudinal axis (104) when the screw actuator (232) rotates; a rotor carrier sleeve (216) operatively 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) comprising a sensor portion (244) and a 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) are mounted in a sensor housing (316) fixed with respect to the steering shaft (118); and the housing (102) comprises a sensor channel (302) configured to receive the sensor housing (316) and constrain the movement of a sensor housing (316) and the steering shaft (118) in a direction parallel to the longitudinal axis (104).

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. The steer-by-wire steering assembly (100) according to claim 1 or 2, wherein the sensor housing (316) is configured to slide within the sensor channel (302).

4. The steer-by-wire steering assembly (100) according to any one of claims 1 to 3, wherein the sensor channel (302) is located within a housing sleeve portion (300) of the housing (102).

5. The steer-by-wire steering assembly (100) according to claim 4, further comprising a mounting assembly (306) fixed to the housing sleeve portion (300) and comprising at least one elongate rail (308) defining the sensor channel (302).

6. The steer-by-wire steering assembly (100) according to claim 5, wherein the mounting assembly (306) further comprises fasteners (310) configured to clamp the at least one elongate rails (308) to an inner surface of the housing sleeve portion (300).

7. The steer-by-wire steering assembly (100) according to any one of claims 1 to 6, wherein the sensor housing (316) comprises a shaft engagement sleeve (320) configured to mount around the steering shaft (118).

8. The steer-by-wire steering assembly (100) according to claim 7, wherein the shaft engagement sleeve (320) comprises a central bore (322) configured to receive the steering shaft (118).

9. The steer-by-wire steering assembly (100) according to any one of claims 1 to 8, wherein the sensor housing (316) comprises a first housing engagement surface (318) and a second housing engagement surface (326) configured to engage respectively with first channel and second channel engagement surfaces (304, 324) of the sensor channel (302).

10. The steer-by-wire steering assembly (100) according to claim 9, wherein the sensor channel (302) comprises a first channel engagement surface (304) configured to engage the first housing engagement surface (318) when the screw actuator (232) rotates in a first direction, and the second channel engagement surface (324) is configured to engage the second housing engagement surface (326) when the screw actuator (232) rotates in a second direction.

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, press fit, or welding.

12. The steer-by-wire steering assembly (100) according to any one of claims 1 to 11 , further comprising a second sensor assembly (500) comprising a second sensor portion (244b) and a second target portion (246a) configured to detect relative movement of the steering shaft (118) with respect to the housing (102).

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. The steer-by-wire steering assembly (100) according to claim 12 or 13, wherein one of the second sensor portion (244b) and the second target portion (246b) are mounted in a second sensor housing (502) fixed with respect to the steering shaft (118).

15. The steer-by-wire steering assembly (100) according to claim 14, wherein the second sensor housing (502) is configured to slide within a second sensor channel (302) in the housing (102).

16. The steer-by-wire steering assembly (100) according to any one of claims 12 to 15, wherein the first and second sensor assemblies (238,500) are mounted at different positions on the steering shaft (118).

17. The steer-by-wire steering assembly (100) according to any one of claims 1 to 16, wherein the motor assembly (206) comprises a first motor (208) and a second motor (210), and the rotor carrier sleeve (216) is operatively coupled between the first motor (208), the second motor (210), and the screw actuator (232).

Images