Separated pilot overflow valve with built-in main control level

By designing a separate pilot relief valve built into the main control stage, the problems of complex structure and poor sealing in the existing technology are solved, achieving flexible flow control and stable unloading effect. It is suitable for the dual pump system of truck-mounted cranes, reducing manufacturing costs and improving the service life of the equipment.

CN224414002UActive Publication Date: 2026-06-26XUZHOU AMCA HYDRAULICS TECHNOLOGY CO LTD
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Patent Information

Application Number
CN202521865096.8
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2025-09-01
Publication Date
2026-06-26
Estimated Expiration
2035-09-01

AI Technical Summary

Technical Problem

Existing pilot-operated relief valves have complex structures, many parts, and poor sealing when adapted to the dual-pump system of truck cranes, resulting in high manufacturing costs, difficult assembly, and short service life. They cannot meet the switching requirements of winch operation between high-speed operation and heavy-load steady speed.

Method used

Design a separate pilot relief valve with built-in main control stage, including pilot stage structure and main control stage structure. It adopts direct-acting relief valve and unloading valve stem. Pilot control pressure oil is provided through pilot stage. The built-in valve stem of main control stage unloads the main oil circuit of another main pump. The structure is simple and flexible and suitable for dual pump system.

Benefits of technology

It achieves flow control with simple structure, large unloading capacity and high stability, reduces manufacturing costs, improves equipment service life and versatility, and meets the operational needs of truck-mounted cranes under different loads.

✦ Generated by Eureka AI based on patent content.
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Abstract

A separated pilot overflow valve with a built-in main control level comprises a pilot level structure and a main control level structure which are connected with a double-pump system, and the pilot level structure provides pilot control pressure oil for the main control level structure; the pilot level structure comprises a valve body, a throttling plug, an adjustable overflow valve, an oil inlet cavity I and an oil return cavity I; the main control level structure comprises a valve body II, an unloading valve rod, a plug, a spring, a signal cavity II, a signal cavity III and an oil return cavity II, the oil inlet cavity I is directly connected with the signal cavity III, and the signal cavity I is connected with the signal cavity III through a pipeline. The double-pump system is provided with the pilot level structure and the main control level structure, the oil inlet cavities of the two structures are connected with the two constant delivery pumps of the double-pump system respectively, the pilot level outputs pilot pressure to control the main control level to act, the main control level unloads a main oil way of the other main pump, and the double-pump system is more flexible in structural layout, larger in unloading amount and more stable in unloading. And moreover, the structure is relatively simple, and the manufacturing cost is low.
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