Hybrid Excavator Turning Control Safety Switch
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Solution Overview
Problem
In hybrid construction machines, when the engine stalls or the driver performs a key off maneuver during a turning operation, the turning motor loses control, leading to potential collisions or injuries due to uncontrolled rotational inertia of the upper turning body.
Innovation Solution
A turning control apparatus with a second switch (Key2) that maintains electric power supply to the hybrid control unit even when the primary switch (Key1) is off, allowing for zero speed control of the turning motor by the hybrid control unit, which also disregards operator inputs and forcibly stops the engine if stalled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the primary switch (Key1) is turned off to stop engine operation, then fuel efficiency is improved and engine emissions are reduced, but the turning motor loses control and the upper turning body becomes uncontrolled due to high rotational inertia
Solution Approach 1:
The patent introduces a second switch (Key2) as an intermediary component that mediates between the primary switch (Key1) and the hybrid control unit. When Key1 is off, Key2 can remain on to maintain power supply to the HCU, enabling it to continue controlling the turning motor and prevent uncontrolled motion from rotational inertia
Solution Approach 2:
The system performs preliminary action by maintaining power supply to the hybrid control unit through Key2 before the turning operation becomes dangerous. This allows the HCU to proactively control the turning motor to stop the upper turning body before uncontrolled collision occurs
2Use of energy by moving object
If electric power is blocked from the battery to the hybrid control unit during engine stop or key off, then power consumption is reduced, but the turning motor cannot be controlled and the upper turning body cannot be stopped safely
Solution Approach 1:
The patent applies local quality by selectively maintaining power supply only to the hybrid control unit through Key2 when needed for turning control, rather than supplying power to the entire system. This localized power maintenance enables safety control while minimizing overall power consumption
3Device complexity
If the hybrid control unit stops operation when power is blocked, then system complexity is reduced, but zero speed control of the turning motor cannot be maintained during engine stall or key off
Solution Approach 1:
The patent segments the power supply control into two independent paths: Key1 for normal operation and Key2 for safety control during turning. This segmentation allows the HCU to maintain zero speed control of the turning motor through Key2 even when Key1 is off, without requiring the entire control system to remain complexly operational
Data Source
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AI summary
A turning control apparatus for a hybrid construction machine according to the present invention may include an engine 10, an oil hydraulic pump 20, an electric energy storage device 30, an engine assistant motor 40, a turning motor 50, a power converter 60, a battery 300 mounted in a vehicle separately from the electric energy storage device, a hybrid control unit (HCU), an SMPS configured to apply operating electric power to the hybrid control unit (HCU) by being supplied with operating electric power from the battery 300, a first switch Key1 configured to switch a VKey_On path which supplies operating electric power from the battery to the SMPS when a key on signal of a driver is inputted, and a second switch Key2 configured to switch a VKey_Out path which allows operating electric power to be supplied from the battery to the SMPS when an operation of the first switch Key1 is stopped, in which the second switch Key2 is switched when it is confirmed that the turning motor 50 is being driven in a state in which an operation of the first switch Key1 is stopped.