Hydraulic Pump Switching for Stable Special Attachment Operation
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Solution Overview
Problem
In hydraulic drive systems for work machines like hydraulic excavators, the operation of special attachments is hindered by insufficient or unstable hydraulic fluid supply due to shared fluid sources with permanently installed actuators, leading to prioritization of other actuators and reduced operability during combined operations.
Innovation Solution
A selector valve is introduced to switch the hydraulic fluid source of special actuators from shared pumps to an additional independent pump, ensuring stable and sufficient fluid supply to special actuators, thereby improving their operability during combined operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If additional hydraulic actuator and permanently installed actuators share hydraulic fluid sources, then device complexity is reduced, but hydraulic fluid supply to additional actuator becomes insufficient or unstable during combined operation
Solution Approach 1:
The hydraulic system is segmented into multiple independent pump groups. The additional hydraulic actuator is assigned to a dedicated pump group rather than sharing a common pump, ensuring independent and stable hydraulic fluid supply. This segmentation resolves the contradiction by maintaining system simplicity while guaranteeing reliable fluid supply to the additional actuator during combined operations.
2Productivity
If multiple hydraulic actuators operate simultaneously from shared pumps, then productivity is improved, but hydraulic fluid distribution becomes unstable
Solution Approach 1:
The system segments hydraulic power sources into dedicated pump groups for different actuator types. This allows multiple actuators to operate simultaneously with stable fluid supply, as each group operates independently without competing for resources. The segmentation enables high productivity through combined operations while maintaining supply consistency.
Data Source
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AI summary
A hydraulic drive system includes a swing directional control valve 81 and a third boom directional control valve 82 that are connected to a third hydraulic pump 33. Furthermore, the hydraulic drive system includes: a second auxiliary directional control valve 84 that is connected to the third hydraulic pump 33, and is connectable with a second special hydraulic actuator 64 for driving special attachments; and a first selector valve 96 that is connected to the third hydraulic pump 33 upstream of the second auxiliary directional control valve 84, and is connectable with an additional hydraulic pump 97. The first selector valve 96 switches the hydraulic fluid source of the second special hydraulic actuator 64 connected to the second auxiliary directional control valve 84 at least between the third hydraulic pump 33 and the additional hydraulic pump 97. Operability for combined operation of a special attachment can be improved in the hydraulic drive system equipped in advance with an auxiliary directional control valve that is connectable with an additional hydraulic actuator for driving the special attachment.