Rotary Hydraulic Machine Seal System Preventing Ring Rotation
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Solution Overview
Problem
Rotary hydraulic motors with radial pistons suffer from rapid wear of o-rings due to alternating rotation of the main ring, necessitating frequent shutdowns for replacement, and lack flexibility in power sizing.
Innovation Solution
The design incorporates a seal system with a first ring, second ring, and o-ring, where the first and second rings are interference-fitted to prevent rotation, and a compensating chamber to distribute forces, reducing friction and wear, and allows for sizing adjustments for various power ratings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the main ring is allowed to rotate freely in the supply conduit, then the seal can accommodate cylinder oscillation, but the o-ring suffers rapid wear due to alternating rotation
Solution Approach 1:
The seal is divided into multiple functional rings: a first ring that rotates with the cylinder to accommodate oscillation, a second ring that remains stationary to prevent o-ring wear, and an o-ring that seals between them. This segmentation allows each component to perform its specific function without suffering the drawbacks of the prior art.
Solution Approach 2:
The first and second rings act as intermediary elements between the oscillating cylinder and the stationary supply conduit. The first ring accommodates the motion, the second ring provides a stable mounting point, and together they protect the o-ring from direct exposure to alternating rotation.
2Productivity
If the motor operates continuously without shutdowns, then productivity increases, but seal wear accumulates requiring frequent maintenance
Solution Approach 1:
The seal design proactively prevents wear by constraining the rotation of the second ring and distributing the mechanical stress away from the o-ring. This preliminary protective action eliminates the need for frequent shutdowns and replacements, enabling continuous operation.
3Device complexity
If the cylinder block has fixed housing seatings arranged in a star fashion, then the structure is simple and robust, but the machine cannot be easily sized for different power ratings
Solution Approach 1:
The housing seatings are made rotatable relative to the cylinder block, transforming the static star-shaped arrangement into a dynamic configuration. This allows the angle and position of the seatings to be adjusted according to different power requirements while maintaining the simple robust structure.
Solution Approach 2:
The ability to rotate the housing seatings provides more configurability than a fixed arrangement, allowing the same basic structure to be adapted to various power ratings by simply changing the angular positions rather than redesigning the entire cylinder block.
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 significantly increases the service life of the seal ring and reduces the need for reconditioning, enabling continuous operation and adaptable power sizing.
Implementation Method 1
The first ring and the second ring are interference-fitted to one another and to the supply conduit in such a way as to prevent rotation with respect to the supply conduit
Implementation Method 2
a compensating chamber to distribute forces, reducing friction and wear
Data Source
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AI summary
A rotary hydraulic machine with radial pistons comprising: a rotating shaft (2); a cylinder-housing body (3), having a plurality of housing seatings (4) arranged radially at equal distances from the rotation axis (R) of the rotating shaft (2); a cylinder (5) housed in each of said plurality of housing seatings (4) and rotating relative to the same around an axis (C) concentric with said rotation axis (R) of the rotating shaft (2); a piston (6) slidable in each cylinder (5) and coupled to a crank (7) of the rotating shaft (2); a supply conduit (12), for each cylinder (5), provided with a seal (120) arranged to enable a sealed connection between the supply conduit (12) and the respective cylinder (5). Each seal (120) comprises: a first ring (121), arranged at an end of the supply conduit (12) and placed in contact with the cylinder (5); a second ring (122), concentric to the first ring (121) and interposed between the supply conduit (12) and the first ring (121), wherein the second ring (122) is coupled by interference with the first ring (121) and is inserted by interference into the supply conduit (12) in such a way as to prevent a rotation of the first ring (121) with respect to the supply conduit (12) around a common axis (X).