Hydraulic Control System for Transmissions with Parallel Planetary Gear Trains

Abstract

The invention relates to a hydraulic control system used for a speed changer of a parallel planetary gear train. The hydraulic control system comprises three bi-directional acting oil cylinders, four single-way acting oil cylinders, a shuttle valve, three external control two-position three-way slide valve, an external control two-position five-way stopping valve, two two-position three-way interlock valve and nine two-position three-way magnetic exchange valves. The hydraulic control system further comprises a main feeding oil pipe, a reverse-gear oil pipe, a forward-gear oil pipe, a manual control slide valve and an oil groove. According to the hydraulic control system, the manual control slide valve can be controlled in a manual mode to enable the speed changer to have a parking state, a backing up state, a neutral-gear state and a forwarding state; through different valve position combinations of various valves in the hydraulic control system, the speed changer can achieve eight forward gears and two reverse gears, and preset of gear changing in a changing process of the forward gears can be achieved. When a TCU loses efficacy completely, the emergency limp function of forward-gear D1 and reverse-gear R1 running is achieved.

Description

technical field [0001] The invention belongs to a hydraulic control system for a vehicle transmission, in particular to a hydraulic control system for a transmission of a vehicle parallel planetary gear train. Background technique [0002] Vehicle transmissions are divided into manual transmissions and automatic transmissions. Manual transmission can only be shifted by manual operation, while automatic transmission can realize automatic gear shifting; according to the structure, automatic transmission is divided into mechanical automatic transmission (AMT), power shift automatic transmission (AT), continuously variable transmission (CVT ) and several types of dual clutch transmission (DSG). At present, the automatic shift function of automatic transmission is generally realized by controlling the shift servo and execution system through the transmission electronic control unit (TCU); the shift servo and execution system can be divided into three types: electric, pneumatic a...

AI Technical Summary

Problems solved by technology

Full hydraulic control means that the control signal and servo execution process are all hydraulic. Since the driver's operation intention, engine and vehicle working status must be converted into hydraulic signals to control automatic transmission, the system is complicated, the control accuracy is low, and the response is low. Slow and high failure rate, it is no longer used in the automatic transmission control of modern vehicles; electro-hydraulic control uses solenoid valves as servo control components to control the actuators of the shift execution system to achieve automatic transmissions. At present, most vehicles use automatic transmissions This type of

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