# US 2026/0097802 A1 · Steer-by-wire steering system

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- Number: US 2026/0097802 A1
- Document ID: US20260097802A1
- Status: Published application
- Kind: A1
- Application number: 19/349,583
- Filed: 2025-10-03
- Published: 2026-04-09
- Earliest claimed: 2024-10-08
- Assignees: Robert Bosch GmbH
- Applicants: Robert Bosch GmbH
- Inventors: Senthilkumar Thulasidass
- Web page: https://patentgrep.com/patent/US20260097802A1

## CPC

- B62D 5/001: {Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup}
- B62D 5/006: {power actuated}
- B62D 5/003: {Backup systems, e.g. for manual steering (B62D5/30 takes precedence)}
- B62D 5/005: {means for generating torque on steering wheel or input member, e.g. feedback}
- B62D 5/04: electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D 5/0409: {Electric motor acting on the steering column}
- B62D 5/0421: {Electric motor acting on or near steering gear}
- B62D 5/046: {Controlling the motor}
- B62D 5/0481: {monitoring the steering system, e.g. failures}
- B62D 5/0484: {for reaction to failures, e.g. limp home}
- B62D 6/008: {Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications}
- B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M)

## Abstract

A steer-by-wire steering system for a vehicle includes a steering wheel actuator and a rack actuator. The steering wheel actuator includes a first motor which is to be controlled via a first output stage. The rack actuator includes a second motor which is to be controlled via a second output stage. A signal and current interface is provided between the steering wheel actuator and the rack actuator that is set up such that the first output stage of the steering wheel actuator is to be controlled via the interface in order to cause passive braking of the first motor.

## Claims

### Claim 1

A steer-by-wire steering system for a vehicle, comprising:
a steering wheel actuator that includes a first motor configured to be controlled via a first output stage;
a rack actuator that includes a second motor configured to be controlled via a second output stage; and
a signal and current interface provided between the steering wheel actuator and the rack actuator,
wherein the signal and current interface is configured such that the first power stage of the steering wheel actuator is to be controlled via the signal and current interface to cause passive braking of the first motor.

### Claim 2 (depends on 1)

The steer-by-wire steering system according to claim 1, wherein an OR gate is provided in a communication link.

### Claim 3 (depends on 2)

The steer-by-wire steering system according to claim 2, wherein the OR gate is implemented by diodes.

### Claim 4 (depends on 1)

The steer-by-wire steering system according to claim 1, wherein a bridge circuit with high side switches and low side switches is provided in the first output stage, and wherein the low side switches are configured to be controlled to cause passive braking.

### Claim 5 (depends on 1)

The steer-by-wire steering system according to claim 1, wherein at least one switch is provided in the signal and current interface to trigger the control of the first output stage for passive braking of the first motor.

### Claim 6 (depends on 1)

The steer-by-wire steering system according to claim 1, wherein another channel is associated with the steering wheel actuator.

### Claim 7 (depends on 2)

The steer-by-wire steering system according to claim 2, wherein the communication link comprises signal lines for the following signals:
a limited power supply for passive damping,
a cosine rotor position sensor,
a sine rotor position sensor, and
ground.

### Claim 8 (depends on 7)

The steer-by-wire steering system according to claim 7, wherein the signal and current interface comprises a signal line for an additional PWM signal.

### Claim 9 (depends on 1)

A method for passively braking a first motor of a steering wheel actuator in the steer-by-wire steering system according to claim 1, wherein the first motor is configured to be controlled via the first output stage, the method comprising:
providing a signal via the signal and current interface between the steering wheel actuator and the rack actuator of the first output stage of the first motor so as to cause passive braking of the first motor.

### Claim 10 (depends on 9)

The method according to claim 9, wherein the first output stage comprises a bridge circuit of switches which include high side switches and low side switches, and wherein the low side switches of the first output stage are controlled for passive braking of the first motor.