Excavator Swing Motor Parking Brake Control
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Solution Overview
Problem
Existing hydraulic excavator systems face challenges in rapidly stopping the upperstructure when relief pressure is lowered due to abnormalities in the swing motor driving circuit, leading to unsatisfactory swing speed reduction and increased wear damage on parking brakes.
Innovation Solution
The system incorporates a dual parking brake control unit, where the first unit applies braking force after a predetermined delay when the swing operation tool is connected to the pilot pump, and the second unit applies force after a shorter delay when the tool is disconnected, ensuring rapid stopping even under abnormal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the parking brake applies braking force immediately after the swing operation tool is disconnected from the pilot pump, then the upperstructure can be stopped rapidly even when relief pressure is reduced, but the wear damage of the parking brake increases
Solution Approach 1:
The system dynamically adjusts the delay time for applying braking force based on the connection state of the swing operation tool to the pilot pump. When disconnected (abnormal state), the delay is shortened to enable rapid stopping. When connected (normal state), the delay is extended to reduce brake wear. This dynamic adjustment resolves the contradiction between rapid stopping and brake wear protection.
2Object-affected harmful factors
If the parking brake applies braking force after a predetermined delay time, then the wear damage of the parking brake is suppressed, but the upperstructure cannot be stopped rapidly when relief pressure is reduced
Solution Approach 1:
The system uses feedback from the connection/disconnection state of the swing operation tool to the pilot pump to adjust the braking control. When the tool is disconnected, the system detects this state and shortens the delay time, enabling rapid stopping when relief pressure is reduced. This feedback mechanism allows the system to adapt braking behavior to actual operating conditions, resolving the contradiction between brake wear suppression and rapid stopping capability.
3Reliability
If the swing operation tool is disconnected from the pilot pump, then the system can respond quickly to abnormal conditions, but the delay time for applying braking force becomes insufficient when relief pressure is reduced
Solution Approach 1:
The system performs preliminary action by detecting the disconnection state of the swing operation tool in advance and preparing to apply braking force with a shortened delay time. This preliminary detection and preparation ensure that when relief pressure is reduced, the braking force is applied as quickly as possible, minimizing the loss of time while maintaining reliability in responding to abnormal conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables rapid and safe stopping of the upperstructure by applying braking force more quickly when relief pressure is reduced, reducing wear on brakes and improving braking functionality.
Implementation Method 1
a hydraulic pump (11), a swing motor (16) which is operated by pressure oil discharged from the hydraulic pump (11)
Implementation Method 2
a parking brake (29) which applies a braking force to the swing motor (16)
Implementation Method 3
a swing direction control valve (14) which controls a flow of the pressure oil supplied from the hydraulic pump (11) to the swing motor (16)
Data Source
Figure 1
Figure 2
AI summary
To rapidly stop a upperstructure even though a relief pressure is lowered due to an abnormality in a hydraulic device included in a swing motor driving circuit while it is intended to stop the upperstructure when a predetermined delay time has passed since a swing operation tool is brought back to a neutral position. According to the present invention, configuration is made so that there are provided: a first choke 34 for controlling a parking brake 29 to apply a braking force to a swing motor 16 when a predetermined delay time T has passed since a swing operation tool 15 is brought back to a neutral position in a state where the swing operation tool 15 is connected to a pilot pump 12; and an on-off valve 36 and a second choke 37 for controlling the parking brake 29 to apply a braking force to the swing motor 16 when a delay time t shorter than the predetermined delay time T has passed since the swing operation tool 15 is brought back to the neutral position and the swing operation tool 15 is disconnected from the pilot pump 12.