Motor driven CVT (continuously variable transmission) electro-hydraulic control system

Abstract

The invention discloses a motor driven CVT (continuously variable transmission) electro-hydraulic control system comprising a driving wheel hydraulic cylinder, a driven wheel hydraulic cylinder, a speed ratio control loop and a clamping force control loop, wherein the speed ratio control loop and the clamping force control loop are connected in parallel on the driving wheel hydraulic cylinder andthe driven wheel hydraulic cylinder. The speed ratio control loop and the clamping force control loop are connected in parallel on two main oil ways of the driving wheel hydraulic cylinder and the driven wheel hydraulic cylinder, respectively control speed ratio and clamping force, are associated with each other without interference and can realize the accurate regulation of any speed ratio and clamping force within a specified range; because a direct current motor is used for driving a CVT hydraulic pump to work, throttle loss, overflow and unloading loss are avoided; and in addition, betterideal power matching of the motor and the hydraulic cylinders of an execution component can be obtained. Moreover, the control system has the advantages of long service life, high reliability, low production cost, small size and light weight and can realize high integration.

Description

technical field [0001] The invention relates to a metal belt type continuously variable transmission, which belongs to the field of continuously variable speed transmission, in particular to a motor-driven CVT electro-hydraulic control system. technical background [0002] Continuously variable transmission is an ideal transmission mode, which has been the goal pursued by people since the birth of automobiles. The metal belt continuously variable automatic transmission can automatically and continuously change the speed ratio according to the driving conditions of the vehicle, so that the engine works according to the best fuel economy curve or the best power curve. Compared with the conventional variable speed transmission, it can significantly improve the fuel economy of the car, improve the power and ride comfort of the car, and reduce the emission pollution of the engine. [0003] In the prior art, most of the automotive metal belt continuously variable transmissions ar...

AI Technical Summary

Problems solved by technology

like figure 1 As shown, the oil pump 1a in the system is driven by the engine. As long as the engine is working, the oil pump 1a and the hydraulic system will work. Especially at present, most of them are gear pumps, which belong to quantitative pumps. In order to ensure the response speed of speed regulation, A certain flow rate must be guaranteed. In order to ensure the clamping force of the hydraulic cylinder on the cone-metal belt, a sufficient pressure must be ensured. Energy loss is inevitable, which is the inherent feature and shortcoming of this pressurization and speed regulation system

In addition to the above-mentioned shortcomings, the electro-hydraulic control system CVT also has the following disadvantages: 1. The oil pump 1a in the electro-hydraulic control system is driven by the engine. A large throttling loss; if the engine speed is low, it will cause the effective range of the pressure valve to be adjusted to decrease, affecting the performance of the continuously variable transmission; 2. The speed ratio control and clamping force control in the electro-hydraulic control system exist The defects of mutual involvement and mutual interference; 3. The clamping force is mainly controlled by the slide valve 2a (proportional valve), but the slide valve is expensive, easy to wear, poor in anti-pollution ability, and poor in economy when operating under low load

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