Hydraulic mechanical continuously variable transmission for loader

Abstract

The invention relates to a hydraulic mechanical continuously variable transmission for a loader and belongs to the technical field of mechanical transmission. The transmission comprises a planet gear a1, a planet gear a2, a planet gear a3, a planet gear a4, a closed transmission hydraulic unit, a high / low gear pair and a combined clutch, wherein the planet gear a1, the planet gear a2, the planet gear a3 and the planet gear a4 are arranged inside a box, the pure hydraulic transmission low gear starting or loader heap operation through the planet gear a1 and a clutch C1, the hydraulic mechanical power dividing, confluence and middle / low gear driving through the planet gear a2 and a clutch C2, the reverse gear is achieved through the planet gear a3 and an arrester B1, and the forward gear is achieved through the planet gear a4 and an arrester B2. A microcomputer control system controls the joint state of clutches and the discharge capacity of a variable pump, the forward reverse multistage continuous hydraulic mechanical continuously variable transmission which is in wide in range and high in efficiency is achieved, and the transmission is suitable to engineering vehicles such as wheel loaders.

Description

technical field [0001] The invention belongs to the technical field of mechanical transmission, and in particular relates to a hydraulic mechanical stepless transmission for a loader. Background technique [0002] At present, the existing ZL series wheel loaders mainly adopt two kinds of transmission system configuration schemes, both of which are hydraulic mechanical transmission. The engine is followed by a single turbo torque converter and four forward gears and four reverse gears (forward four gears or reverse three gears) or front three rear three fixed shaft power shift transmissions. The above two transmission schemes can meet the working requirements of the loader, such as automatically changing the speed and torque with the size of the load. At the same time, this change range is also very wide, which is more suitable for the loader's high-speed low-torque driving and low-speed high-torque operating conditions. , The flexible connection performance of the hydraulic...

AI Technical Summary

Problems solved by technology

However, hydromechanical transmission also has its prominent shortcomings, such as poor stress and lubrication conditions for the overrunning clutch in the twin-turbine torque converter, and poor reliability; the use of power internal split hydraulic mechanical transmission has large power loss, resulting in high efficiency. Low, narrow range of high-efficiency zone, so that the overall efficiency of the whole machine is low; at the same time, the planetary structure is complex, difficult to manufacture, and inconvenient to maintain

Moreover, there are problems that it cannot be adjusted according to the operating conditions of the loader, and the efficiency is very low when the loader starts and shovels.

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