Pump/motor-based parallel-series hybrid hydraulic excavator driving system

Abstract

The invention discloses a pump / motor-based parallel-series hybrid hydraulic excavator driving system, which comprises a movable arm driving cylinder, a mounting mechanism, an electric quantity storage unit, a hydraulic control element, a group of other actuating mechanism consisting of a bucket cylinder, a bucket arm cylinder and a travel hydraulic motor, an engine, a first motor and a variable displacement pump which are in coaxial mechanical transmission connection with the other actuating mechanism, and a second motor, a pump / motor, an electromagnetic clutch and a speed reducer which are in coaxial mechanical transmission connection with the mounting mechanism. The displacement pump is connected to the other actuating mechanism through a hydraulic main control valve; the first motor iselectrically connected with the electric quantity storage unit; the second motor is electrically connected with the electric quantity storage unit; the hydraulic control element is communicated with oil circuits of the movable arm driving cylinder, a parallel hybrid system, a series hybrid system and the other actuating mechanism. The efficiency of an energy recovery system is improved, the flowing flexibility of recoverable energy and the diversity of control modes are increased, and the cost is reduced.

Description

technical field [0001] The invention relates to the technology in the field of drive systems, in particular to an energy-saving drive system for a pump / motor-based hybrid hydraulic excavator. Background technique [0002] With the increasingly serious problems of energy shortage and environmental pollution worldwide, it is of great practical significance to study the energy saving of hydraulic excavators. The energy saving of hydraulic excavators has been widely concerned by the industry. During the working process of the hydraulic excavator, the up and down swing of the boom and the rotary motion of the boarding mechanism are relatively frequent, and because the inertia of each moving part is relatively large, a large amount of potential energy and energy will be released when decelerating and braking. This part of energy It is usually consumed on the valve port of the hydraulic valve, which not only wastes energy, but also leads to system heating and reduced component lif...

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Problems solved by technology

[0004] In this technical solution, the generator in the boom potential energy recovery scheme and the motor in the slewing braking energy recovery scheme are two different motors, which have high cost, complex structure, and large volume. At the same time, the recovery of all potential energy and braking kinetic energy Reuse has undergone multiple energy conversions from recoverable energy-hydraulic energy-mechanical energy-electrical energy-mechanical energy. The energy flow in the system is very complicated, which affects the energy recovery efficiency of the system.

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