Vehicular electrically-controlled hydraulic power steering system

Abstract

The invention relates to a vehicular electrically-controlled hydraulic power steering system, which comprises a steering oil pump, a steering control valve, a steering power cylinder, controllers, an oil tank, a vehicle speed sensor, a steering angular speed sensor, an oil outlet pipe, an oil return pipe and a bypass with valves. An oil outlet of the steering oil pump is connected with the oil outlet pipe and then connected with the oil return pipe through the steering control valve to be further connected into the oil tank. The vehicular electrically-controlled hydraulic power steering system is characterized in that two or more than two electromagnetic valves are parallelly connected in the bypass, and on and off of the valves are controlled by the controllers respectively. The two or more electromagnetic valves are parallelly connected to form an electromagnetic valve combination unit serving as the bypass, variable-flow control in various modes can be realized, and the whole running process can be provided with excellent power assistance.

Description

technical field [0001] The invention relates to an electronically controlled hydraulic power steering system for a vehicle, in particular to an electronically controlled hydraulic power steering system for a vehicle that can change the pressure and flow of fluid flowing into a rotary valve of a power steering gear. Background technique [0002] Currently, hydraulic power steering systems are widely used in automobiles, usually including hydraulic pumps, oil storage tanks, steering control valves, etc. Adjust the flow of hydraulic oil to control the steering system according to the driving state of the vehicle. During the steering process of the vehicle, the steering action is still completed by the driver, and the oil pressure of the power steering system only assists the steering, that is, the oil pressure is used to help the driver complete the steering action, making it light and labor-saving. In the prior art, when the vehicle is running at a low speed, the steering whe...

AI Technical Summary

Problems solved by technology

In the prior art, when the vehicle is running at a low speed, the steering wheel is easy to manipulate. When the vehicle speed is fast, the rotation speed of the steering oil pump also increases, resulting in an increase in the flow of hydraulic oil, which generates a large boost and makes the steering wheel rotate. If it is too light, it is easy to lose the sense of road, causing the problem of "floating" of the car, which reduces the safety performance of the car

[0003] Because the traditional hydraulic power steering system cannot effectively solve the contradiction between "lightness" and "spirit" in steering, and the mutual restriction between steering force and road feel, people propose an electronically controlled hydraulic power steering system to control the flow into the steering valve. For a good assist feel

Typical solutions include: Chinese patent 200320118460.1, titled "Automotive Electronically Controlled Hydraulic Power Steering System", uses a stepper motor to adjust the size of the throttle port of the bypass valve to control the flow of hydraulic oil entering the steering control valve. This improvement scheme can solve the problem of losing road sense when the car turns at high speed to a certain extent, but this form has complex structure, high cost, and is difficult to control; valve to adjust the size of the orifice of the bypass valve to control the flow of hydraulic oil, but this solution has higher requirements for the accuracy of the electromagnetic proportional valve itself, and more stringent requirements for the controller, and the needle valve is used in actual use. Often unable to withstand the high pressure, the phenomenon of opening instability occurs. In Chinese patent 200720034596.2, a DC motor is used to directly drive the oil pump. This structure adds a motor and other connection mechanisms to the original power steering. The structure is more complicated, and the DC motor It's not easy to control

[0004] The solutions above are still unsatisfactory for the reasons analyzed and need to be improved

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