Pivot Joint Pin-Groove Coupling to Minimize Hydraulic Tipping Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic devices experience tipping torque due to varying pressure fields between the drum plate and sleeves, leading to increased friction and potential wear, which limits their maximum operational speed.
Innovation Solution
The implementation of multiple pin-groove couplings with adjustable groove widths allows for a plurality of pivot axes at equiangular distances, enabling the barrel plate and shaft to maintain relative positions where the centerlines of barrel plate ports fluctuate within the range of sleeve openings, thereby minimizing tipping torque and allowing higher maximum speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single key-way coupling is used between the drum plate and shaft, then the drum plate can rotate with the shaft, but varying pressure fields cause tipping torque that increases friction and wear
Solution Approach 1:
The single key-way coupling is segmented into multiple pin-groove couplings distributed around the drum plate. Each pin-groove coupling creates an independent pivot axis, dividing the single coupling function into multiple distributed coupling points that collectively reduce tipping torque through geometric distribution.
Solution Approach 2:
The solution transitions from a single-plane key-way coupling to a three-dimensional arrangement of multiple pivot axes distributed around the drum plate periphery. This spatial distribution in multiple dimensions allows the system to counteract tipping torque more effectively by creating balanced support points.
2Adaptability or versatility
If the groove width is increased to allow pin movement, then kinematic conflicts are mitigated, but manufacturing precision requirements increase
Solution Approach 1:
The groove width is designed to be dynamically adjustable within specific tolerance ranges, allowing the pin to move freely within the groove to accommodate varying operational conditions. This dynamic dimensioning provides adaptability while maintaining manufacturability through standardized tolerance specifications.
3Force
If multiple pin-groove couplings are implemented, then tipping torque is minimized, but device complexity increases
Solution Approach 1:
Multiple pin-groove couplings are merged into a unified structural arrangement where the pins and grooves are integrated into the drum plate and shaft assembly. This merging approach reduces the need for separate coupling components while achieving the force distribution benefits of multiple pivot axes.
Data Source
AI summary
A hydraulic device (1) comprises a housing (2) and a shaft (3) which is rotatable about a first axis of rotation (4). The shaft (3) has a flange (8), a partly spherical portion (16) and a plurality of pistons (9), which are fixed to the flange (8). The device (1) also has a plurality of cylindrical sleeves (11), wherein each sleeve (11) has a sleeve bottom (13) comprising a sleeve opening (14) including a centreline (23). The sleeves (11) cooperate with the pistons (9) to form respective compression chambers (12) of variable volume. A barrel plate (15) is mounted on the partly spherical portion (16) and has barrel plate ports (21) including respective centrelines (22). The sleeves (11) are rotatable about a second axis of rotation (19) which intersects the first axis of rotation (4) by an acute swash angle. The barrel plate (15) is coupled to the shaft (3) in rotational direction thereof by means of a plurality of pin-groove couplings creating a plurality of pivot axes (24) about the second axis of rotation (19). The widths of the grooves (18) allow the pins (17) to move within the respective corresponding grooves (18) in rotational direction about the second axis of rotation (19) under operating conditions. The relative position of the shaft (3) and the barrel plate (15) in rotational direction about the second axis of rotation (19) is adapted such that under operating conditions each centreline (22) of the respective barrel plate ports (21) fluctuates in rotational direction about the second axis of rotation (19) with respect to the centreline (23) of the corresponding sleeve opening (14) within a range in which the centreline (23) of the sleeve opening (14) lies.