Hydraulic Cylinder Buffer Sleeve Sealing Mechanism
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Solution Overview
Problem
Existing hydraulic oil cylinder buffer mechanisms for large cylinder diameters and long strokes face issues with high manufacturing precision requirements and frequent failures due to the small fitting space between the buffer sleeve and buffer inner hole, leading to operational inefficiencies and production bottlenecks in construction machinery like excavators.
Innovation Solution
A hydraulic oil cylinder buffer system with a throttling oil channel and sealing surface mechanism, where the buffer sleeve forms a sealing surface with the rodless cavity end surface, creating a one-way valve that restricts oil passage through a narrow throttling oil channel, providing reliable buffering and reducing manufacturing precision needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a small buffer sleeve is used to block the oil-returning passage, then the buffer effect is achieved, but the fitting precision requirement becomes extremely high and failures occur frequently
Solution Approach 1:
The buffer mechanism is segmented into two independent parts: the buffer sleeve (movable component) and the buffer inner hole (fixed component). The buffer sleeve is designed to slide along the piston rod rather than fit tightly within a fixed hole. This segmentation allows each component to be manufactured independently with lower precision requirements, while still achieving reliable buffering through their coordinated interaction during piston rod retraction.
Solution Approach 2:
Instead of making the buffer sleeve fit tightly within a fixed buffer inner hole (traditional approach), the invention inverts the relationship by making the buffer sleeve slide along the piston rod with a loose fit. The buffering function is achieved not through tight fitting but through the controlled interaction between the buffer sleeve's end face and the piston rod's end face, combined with oil pressure differential. This inversion dramatically reduces manufacturing precision requirements.
2Ease of operation
If the buffer sleeve repeatedly inserts into the buffer inner hole at high speed under huge load, then the buffering function is performed, but the piston rod tilts and buffer insertion failures occur
Solution Approach 1:
The buffer mechanism transitions from a static tight-fit design to a dynamic sliding design. The buffer sleeve is designed to slide freely along the piston rod during normal operation and only engages for buffering when the piston rod approaches the end of its retraction stroke. This dynamic design allows the buffer sleeve to accommodate high-speed movements and huge loads without requiring precise alignment, eliminating the tilt and insertion failure problems.
Solution Approach 2:
The piston rod acts as an intermediary element between the buffer sleeve and the cylinder head. The buffer sleeve slides along the piston rod, using it as a guide and support, rather than directly inserting into the cylinder head. This intermediary relationship provides mechanical guidance that prevents tilting under load and ensures reliable engagement during buffering events.
3Device complexity
If a compression spring is used as buffer device, then the structure is simple, but the spring cannot obtain sufficient elasticity and will be damaged under high pressure
Solution Approach 1:
The invention replaces the mechanical spring buffer with a hydraulic buffer mechanism. The buffer sleeve, when engaged, traps hydraulic oil between itself and the piston rod end face, creating a hydraulic pressure differential that provides the buffering force. This hydraulic approach leverages the incompressibility of oil to provide strong, reliable buffering capability that can withstand high pressures without the structural limitations of a spring, while maintaining relatively simple device architecture.
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
The solution ensures reliable buffering under high load and frequency conditions, extends the service life of the hydraulic oil cylinder, and simplifies production by reducing manufacturing precision requirements, thereby enhancing the production capacity of construction machinery.
Implementation Method 1
a throttling oil channel, extending axially and linearly between the piston rod additional section and the buffer sleeve... the throttling oil channel provides an oil passage for the hydraulic oil in the buffer oil cavity to flow to a side of the rodless cavity oil-passing hole
Implementation Method 2
the first end surface of the buffer sleeve forms a sealing surface with the rodless cavity end surface arranged in the rodless cavity, so as to block the oil passage
Implementation Method 3
The hydraulic oil in the buffer oil cavity being pushed by the piston has a higher oil pressure and may press the first end surface of the buffer sleeve against the rodless cavity sealing end surface tightly
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A hydraulic oil cylinder has a buffer sleeve (4), a rodless cavity sealing end face (1-2) and at least one throttle oil channel (3-1). The buffer sleeve (4) is sleeved on an additional section (3a) of a piston rod in the rodless cavity (2-2) and axially slidable along the additional section (3a) of the piston rod. The rodless cavity sealing end face (1-2) is provided in an oil cylinder cavity between a rodless cavity oil passing hole (1-1) and the termination of the rodless cavity end face of the piston for the retraction process of the piston rod (3), and enables to block the buffer sleeve (4) and attach to the first end surface (4-1) of the buffer sleeve thereby forming a sealing surface. The hydraulic oil at the side of the sealing surface adjacent to the piston (6) can flow to the rodless cavity oil passing hole (1-1) via the throttle oil channel (3-1) when the piston (6) moves from the position, where the first end face (4-1) of the buffer sleeve is attached to the rodless cavity sealing end face (1-2) and the sealing surface is formed, to the position where the piston (6) retracts to the termination during the retraction process of the piston rod (3). The hydraulic oil cylinder has the advantages of simple machining of the buffer structure and good effects. A hydraulic buffer system, an excavator and a concrete pump truck with the above hydraulic oil cylinder are also disclosed.