Hydraulic drive system for traveling work machine

The hydraulic drive system for excavators addresses hunting and workability issues by dynamically adjusting motor capacities based on load thresholds, ensuring efficient high-speed travel and maintaining workability across varying ground conditions.

JP7764736B2Active Publication Date: 2025-11-06KOBELCO CONSTR MASCH CO LTD
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Patent Information

Application Number
JP2021184753
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2021-11-12
Publication Date
2025-11-06
Estimated Expiration
2041-11-12

AI Technical Summary

Technical Problem

Existing hydraulic drive systems for traveling work machines, such as excavators, face issues with hunting and reduced workability when switching from straight-line to curved travel due to varying traveling loads and ground conditions, leading to inefficient high-speed travel.

Method used

A hydraulic drive system with a controller that switches motor capacities between first and second capacities based on preset thresholds, maintaining appropriate torque and preventing hunting by adjusting motor displacement according to pump load fluctuations, regardless of ground conditions or material.

Benefits of technology

The system ensures high-speed travel and suppresses hunting, maintaining workability by adapting motor displacement to ground conditions and material variations, preventing excessive torque and fluctuations.

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Abstract

To provide a hydraulic drive device of a trave-type work machine capable of suppressing deterioration in workability during curved advancing regardless of a material of the portion of the traveling device in contact with the ground and the condition of the ground.SOLUTION: In a hydraulic drive device of a trave-type work machine, when a travel state is switched from a straight advancing state to a curved advancing state, a controller 70 maintains a motor capacity to a second capacity when a pump load is less than a first switching threshold, and switches the motor capacity from the second capacity to a first capacity when the pump load is equal to or higher than the first switching threshold. In a state where the motor capacity is set to the first capacity, when the travel state is the curved advancing state, the controller 70 maintains the motor capacity at the first capacity. When the travel state is switched from the curved advancing state to the straight advancing state, the controller 70 maintains the motor capacity to the first capacity when the pump load is equal to or higher than a second switching threshold, and switches the motor capacity from the first capacity to the second capacity when the pump load is less than the second switching threshold.SELECTED DRAWING: Figure 3
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