An active steering system for an articulated bus is provided. In an assisted steering mode, a hydraulic turntable assists in the steering action of the articulated bus. While the articulated bus is linearly driven at a high speed or the lane-changing action is performed, the assisted steering mode can provide stable driving performance. In the assisted steering mode, a better steering trajectory is achieved while a cornering action of the articulated bus is performed. By collecting the information about the driving velocity, the position of the transmission gear and the position of the steering wheel, a steering force applied to the front frame and the trailer frame is calculated. Moreover, if the control unit judges that the angle of the hydraulic turntable is optimal, a locking force is generated to assure the optimal angle of the articulated bus. The assisted steering mode also supports the action of reversing the articulated bus. When the articulated joint is adjusted to an optimal trajectory, the articulated bus is reversed to the designated position.

A steering assistance actuator for a vehicle includes a actuator shaft, a torque sensor, a motor, a drive mechanism and a drive housing. The actuator shaft is rotatable about a first axis. The actuator shaft includes an integral torque sensor. The motor has an output shaft rotatable about a second axis. The second axis is substantially parallel to the first axis. The drive mechanism is disposed between and drivingly connects the motor and the steering column. The drive mechanism provides a speed reduction from the motor to the actuator shaft. The drive housing encloses the torque sensor and the drive mechanism and is separate from a steering gear. The drive housing also has a mounting feature to which a housing of the motor is fixed. The drive housing also has a first bearing and a second bearing rotatably supporting the actuator shaft in the drive housing.

A steering assistance actuator for a vehicle includes a actuator shaft, a torque sensor, a motor, a drive mechanism and a drive housing. The actuator shaft is rotatable about a first axis. The actuator shaft includes an integral torque sensor. The motor has an output shaft rotatable about a second axis. The second axis is substantially parallel to the first axis. The drive mechanism is disposed between and drivingly connects the motor and the steering column. The drive mechanism provides a speed reduction from the motor to the actuator shaft. The drive housing encloses the torque sensor and the drive mechanism and is separate from a steering gear. The drive housing also has a mounting feature to which a housing of the motor is fixed. The drive housing also has a first bearing and a second bearing rotatably supporting the actuator shaft in the drive housing.

A vehicle and vehicle drive apparatus having a hydraulic pump and a first and second hydraulic motor, each disposed on a center section, is disclosed. A main housing having a housing cover contains the hydraulic pump and the first and second hydraulic motors, which in turn drive first and second motor shafts, respectively. The first and second motor shafts are enclosed in first and second motor shaft housings, respectively, and the main housing combined with the housing cover and the first and second motor shaft housings form a sealed sump. The main housing has mounted thereon a pinion shaft, a pinion gear and a steering rack meshed with the pinion gear. A first steering arm is rotatably mounted to the first motor shaft housing and connected to the steering rack and a second steering arm is rotatably mounted to the second motor shaft housing and connected to the steering rack.

A vehicle and vehicle drive apparatus having a hydraulic pump and a first and second hydraulic motor, each disposed on a center section, is disclosed. A main housing having a housing cover contains the hydraulic pump and the first and second hydraulic motors, which in turn drive first and second motor shafts, respectively. The first and second motor shafts are enclosed in first and second motor shaft housings, respectively, and the main housing combined with the housing cover and the first and second motor shaft housings form a sealed sump. The main housing has mounted thereon a pinion shaft, a pinion gear and a steering rack meshed with the pinion gear. A first steering arm is rotatably mounted to the first motor shaft housing and connected to the steering rack and a second steering arm is rotatably mounted to the second motor shaft housing and connected to the steering rack.

An electric-control multimode steering valve comprises: a flow distributing and collecting valve, a first electromagnetic valve, and a second electromagnetic valve. A valve body comprises four groups of paired valve oil ports. First oil ports of the first and second electromagnetic valves are in communication with a first group. Second oil ports of the first and second electromagnetic valves are in communication with a second group. A third oil port of the first electromagnetic valve is in communication with a flow collecting port of the flow distributing and collecting valve. A first flow distributing port of the flow distributing and collecting valve and a third oil port of the second electromagnetic valve are in communication with a third group. A second flow distributing port of the flow distributing and collecting valve and the third oil port of the second electromagnetic valve are in communication with a fourth group.

An electric-control multimode steering valve comprises: a flow distributing and collecting valve, a first electromagnetic valve, and a second electromagnetic valve. A valve body comprises four groups of paired valve oil ports. First oil ports of the first and second electromagnetic valves are in communication with a first group. Second oil ports of the first and second electromagnetic valves are in communication with a second group. A third oil port of the first electromagnetic valve is in communication with a flow collecting port of the flow distributing and collecting valve. A first flow distributing port of the flow distributing and collecting valve and a third oil port of the second electromagnetic valve are in communication with a third group. A second flow distributing port of the flow distributing and collecting valve and the third oil port of the second electromagnetic valve are in communication with a fourth group.

A hydraulic steering system, comprising a steering pump and a plurality of digital steering cylinder assemblies. Each digital steering cylinder assembly includes a steering cylinder and a digital hydraulic valve configured to selectively communicate a rodless cavity of the steering cylinder with one of the steering pump and a return oil circuit, and communicate a rod cavity of the steering cylinder with the other of the steering pump and the return oil circuit. A controller can be configured to emit a digital pulse signal to a motor and cause the digital hydraulic valve to move towards a first working position or a second working position. A mechanical feedback structure can be configured to be driven by a piston rod of the steering cylinder when the valve core of the digital hydraulic valve moves towards the first working position or the second working position, so as to drive the digital hydraulic valve to return to a neutral position. The system can improve the control precision and the response speed of the steering system.

A hydraulic steering system, comprising a steering pump and a plurality of digital steering cylinder assemblies. Each digital steering cylinder assembly includes a steering cylinder and a digital hydraulic valve configured to selectively communicate a rodless cavity of the steering cylinder with one of the steering pump and a return oil circuit, and communicate a rod cavity of the steering cylinder with the other of the steering pump and the return oil circuit. A controller can be configured to emit a digital pulse signal to a motor and cause the digital hydraulic valve to move towards a first working position or a second working position. A mechanical feedback structure can be configured to be driven by a piston rod of the steering cylinder when the valve core of the digital hydraulic valve moves towards the first working position or the second working position, so as to drive the digital hydraulic valve to return to a neutral position. The system can improve the control precision and the response speed of the steering system.

Steering systems and related methods are disclosed. An example apparatus includes a vehicle frame and a steering linkage assembly including a drag link having a first end and a second end opposite the first end. The apparatus further including at least one of: a hydraulic power assist system to couple to the vehicle frame, the hydraulic power assist system to couple to the first end of the drag link via a first pitman arm; or an electric power assist system to couple to the vehicle frame, the electric power assist system to couple to the first end of the drag link via a second pitman arm, the first pitman arm different than the second pitman arm to enable the first pitman arm and the second pitman to have a common pitman to hardpoint connection with the drag link of the steering linkage assembly.