Energy recovery system with reservoir and variable release

Abstract

An oscillating energy recovery system (50) for a machine (10) is disclosed. The swing energy recovery system may have a pump (58) configured to pressurize fluid, a motor (49) driven by a flow of pressurized fluid from the pump and configured to receive pressurized fluid discharged from the motor and select An energy recovery arrangement (104) is selectively supplied to the motor. A selector valve (120), fill valve (122), and drain valve (124) may be selectively used to fill and drain the at least one reservoir (108, 110). The swing energy recovery system may also have a pressure relief valve (146) associated with the motor and a controller (100) in communication with the energy recovery arrangement and the pressure relief valve. The controller may be configured to selectively adjust the setting of the pressure relief valve based on operating conditions of the energy recovery arrangement.

Description

technical field [0001] The present invention relates generally to hydraulic systems, and more particularly to an oscillating energy recovery system with variable release. Background technique [0002] Oscillating excavation machines such as hydraulic excavators and front shovels require significant hydraulic pressure and flow to move material from the digging position to the dumping position. These machines direct high-pressure fluid from an engine-driven pump through a swing motor to accelerate a loaded work tool at the beginning of each swing, and then restrict fluid flow away from the motor at the end of each swing to slow and stop the work tool. [0003] One issue associated with such hydraulic arrangements concerns efficiency. In particular, the fluid exiting the swing motor at the end of each swing is under relatively high pressure due to deceleration of the loaded work tool. Unless recovered, the energy associated with high pressure fluid is wasted. Additionally, t...

AI Technical Summary

Problems solved by technology

[0005] While the hydraulic control system of the '852 patent can help improve the efficiency of swing machines in some situations, it is not ideal

In particular, some of the pressurized fluid leaving the swing motor may still have useful energy wasted during the draining of the reservoir described in the '852 patent.

Additionally, the '852 patent is only provided for a single relief pressure setting, which can be problematic in some circumstances, such as those involving reservoir failure

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