Hybrid-type construction machine

Abstract

Provided is a hybrid-type construction machine capable of executing revolving operation with the same sense of operation as that of conventional construction machines, with an electrical storage device whose electrical storage quantity can be controlled to be within an appropriate range in view of operational life without increasing the capacity of the electrical storage device. The hybrid-type construction machine is provided with: an electric motor and a hydraulic motor for driving a revolving superstructure; an electrical storage device; and a controller for controlling charging and discharging of the electrical storage device. The controller includes: a memory unit storing, with regard to the electrical storage quantity of the electrical storage device, a discharge command region that is set in accordance with the revolving speed of the revolving superstructure; and a computing unit for computing an additional drive torque command value for the electric motor for increasing the powering amount of the electric motor in accordance with the electrical storage quantity of the electrical storage device when the electrical storage quantity of the electrical storage device has reached the discharge command region stored in the memory unit, and for outputting the additional drive torque command value to the electric motor in order to drive the revolving superstructure.

Description

technical field [0001] The present invention relates to a hybrid construction machine having a revolving body such as a hydraulic excavator, and more particularly to a hybrid construction machine having a revolving body including an electric motor for driving the revolving body and an electric storage device. Background technique [0002] In the past, the mainstream of construction machines with rotating bodies such as hydraulic excavators was to drive the hydraulic pump with the engine, and the hydraulic motor was rotated by the hydraulic pressure discharged from the hydraulic pump to drive the rotating body, which is an inertial body. However, in recent years, In order to improve the fuel efficiency of the engine, reduce the noise level, and reduce the amount of exhaust gas, etc., a hybrid system is proposed to drive the rotating body using both the electric motor and the hydraulic motor that are driven by receiving electric energy from the power storage device. machine (f...

AI Technical Summary

Problems solved by technology

[0010] In addition, if there is a large-capacity power storage device, although the above-mentioned energy management can be unnecessary, there is a disadvantage that as the capacity of the power storage device increases, the installation space of the power storage device in the construction machine increases, And the cost of construction machinery becomes high

[0011] In addition, even if energy management is implemented so that the storage capacity of the power storage device is within an appropriate range of use in consideration of the service life, since the mechanical operation mode is not specified, the energy consumed by the electric motor during acceleration driving The difference between the electric energy and the electric energy generated by the electric motor during deceleration driving, and the storage capacity of the electric storage device may exceed the appropriate range

In order to prevent this situation, it is considered to increase the capacity of the power storage device, but as mentioned above, it is not desirable to increase the capacity of the power storage device from the viewpoint of installation space and cost.

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