eps of a large vehicle

Abstract

The invention discloses an EPS for a large vehicle. The EPS mainly comprises a mechanical drive mechanism, a power assist cylinder, a torque angle sensor, a safety valve, a steering wheel, a hydraulicpump, a servo motor, a controller and a steering wheel connection torque angle sensor, torque and angle information of the torque angle sensor is transmitted to the controller, the torque angle sensor is connected to the mechanical drive mechanism, one end of the mechanical drive mechanism is connected to the power assist cylinder, the power assist cylinder is connected to the safety valve, the safety valve is connected to the hydraulic pump, the hydraulic pump is connected with the servo motor, and the servo motor is also connected with the controller. The design of the EPS eliminates the requirement of the reverse transmission of a system, can be applied to the large vehicle, has reliable system reliability, saves energy, and meets the safety requirements of steering; the system can bematched with existing maturity hydraulic assisting actuators such as a large hydraulic recirculating ball steering machine.

Description

technical field [0001] The invention relates to the field of vehicles, in particular to an EPS of a large vehicle. Background technique [0002] The widely used EPS system is composed of torque sensor, controller, torque servo motor, worm gear reducer and steering mechanism at its core. The control ECU controls the output torque of the booster motor according to the status signal of the vehicle and the detected torque value of the torque sensor. The output of the motor is decelerated and increased by the reduction mechanism to complete the booster. The reduction mechanism is generally a worm gear reducer. Several typical The reduction ratio is 16.5:1 to 22.5:1. The deceleration mechanism has the ability of reverse transmission, so that when the power assist system fails, it can still be operated by hand to ensure the safe operation of the vehicle. The electric motor drives the hydraulic oil through the hydraulic pump. After the hydraulic oil is adjusted in the steering val...

AI Technical Summary

Problems solved by technology

The modified system cannot provide a large power assist, because when the assist power is greater, the system's own assist will increase accordingly, so that the system may self-lock when the assist system fails, which is not allowed in terms of vehicle safety

Therefore, it can only be applied to less than 1KW at present, and it is used for passenger cars or small commercial vehicles, and cannot be applied to large commercial vehicles that require high power assistance.

[0004] The hydraulically assisted EHPS system uses a motor to drive the hydraulic pump. The pressure on both sides of the booster cylinder is controlled through the torsion bar valve. By adjusting the state of the oil pump motor, the working pressure of the system is changed in stages, which overcomes the large energy consumption of the HPS system and the inability to adjust the booster. However, the pressure adjustment method of the overflow control still has a pressure loss, which leads to an increase in the energy loss of the system, and is also an important factor for the early aging of the hydraulic oil.

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