Hydraulic Rotator Vane Sealing and Axial Load Separation
Solution Overview
Problem
Conventional hydraulic rotators face challenges in achieving precise fit and strength to handle high mechanical demands, leading to difficulties in production and efficiency due to the need for high precision and robustness to prevent motor seizure under axial forces.
Innovation Solution
A hydraulic rotator design featuring a rotor with radially extending vanes and a stator with circumferential rims to guide and seal the vanes, allowing for a gap between the rotor and stator, which reduces production costs and internal leakage, and separates axial load bearing from the active interaction, using an axial bearing for load support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If high precision fit is implemented between rotor and stator to minimize internal leakage, then motor efficiency is improved, but manufacturing difficulty and cost increase
Solution Approach 1:
The interaction between rotor and stator is segmented into two distinct zones: a central active interaction zone with controlled gap for vanes, and peripheral contact zones at the ends for axial force handling. This segmentation allows each zone to be optimized independently - the central zone tolerates larger gaps reducing manufacturing precision requirements while the peripheral zones provide precise force transmission.
Solution Approach 2:
The vanes act as intermediary elements between the rotor and stator. Instead of requiring direct high-precision contact between rotor and stator surfaces, the vanes mediate the interaction by extending from the rotor to engage with the stator's circumferential track, allowing for tolerance compensation while maintaining hydraulic sealing.
2Loss of energy
If high precision fit is implemented between rotor and stator to minimize internal leakage, then motor efficiency is improved, but production cost increases
Solution Approach 1:
The interaction between rotor and stator is segmented into two distinct zones: a central active interaction zone with controlled gap for vanes, and peripheral contact zones at the ends for axial force handling. This segmentation allows each zone to be optimized independently - the central zone tolerates larger gaps reducing manufacturing precision requirements while the peripheral zones provide precise force transmission.
Solution Approach 2:
The vanes act as intermediary elements between the rotor and stator. Instead of requiring direct high-precision contact between rotor and stator surfaces, the vanes mediate the interaction by extending from the rotor to engage with the stator's circumferential track, allowing for tolerance compensation while maintaining hydraulic sealing.
3Reliability
If rotor and stator are dimensioned to cope with axial forces, then reliability is improved, but device complexity increases
Solution Approach 1:
The axial force handling function is extracted from the central active interaction zone and relocated to the peripheral end zones. The circumferential track and vanes are designed to handle radial and tangential forces, while the peripheral contact surfaces between rotor and stator specifically handle axial forces, separating the functions to simplify the overall design.
Solution Approach 2:
The interaction between rotor and stator is segmented into two distinct zones: a central active interaction zone with controlled gap for vanes, and peripheral contact zones at the ends for axial force handling. This segmentation allows each zone to be optimized independently - the central zone tolerates larger gaps reducing manufacturing precision requirements while the peripheral zones provide precise force transmission.
4Loss of energy
If vanes are made precise relative to stator chambers to minimize internal leakage, then motor efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The vanes are designed to be self-adjusting through their interaction with the circumferential track. As the rotor rotates and hydraulic pressure acts on the vanes, they automatically maintain optimal positioning within the track, compensating for manufacturing tolerances. The track geometry guides the vanes into correct angular positioning without requiring extremely tight manufacturing tolerances.
Solution Approach 2:
The vane-track interaction is designed to be dynamic rather than static. The vanes can move slightly within the circumferential track in response to hydraulic pressure variations and rotor position, allowing them to self-optimize their sealing contact. This dynamic adjustment capability reduces the need for high initial manufacturing precision.
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 design enhances precision and tolerance to external loads, improves motor efficiency, and reduces production costs by allowing less stringent alignment requirements, while maintaining robustness against axial forces.
Implementation Method 1
Vanes extend from the circumferential protrusion and are in operation driven by a pressure acting in chambers formed in the circumferential track
Implementation Method 2
A rotator includes a motor, typically a hydraulic vane motor, to provide the rotational movement
Implementation Method 3
a track is formed between the first and second circumferential rims, such that a gap exist between the external surface of the rotor and the inner circumferential surface
Data Source
Figure 1~1C
Figure 2~3A
Figure 4~7
AI summary
The invention relates to a hydraulic rotator (11) for rotating a tool with respect to a crane arm, the hydraulic rotator comprising a first attachment piece (12) for connection to a crane arm and a second attachment piece (13) for connection to a tool; and a stator (14) and a rotor (15), the rotor (15) being rotatably arranged inside the stator (14) to rotate around an axial axis (A), wherein the rotor (15) comprises vanes (18) that are biased to extend radially outwards from said rotor (15), and wherein the stator (14) comprises an inner circumferential surface (25) to receive said vanes (18), which inner circumferential surface (25) comprises at least two chambers (19a) arranged to receive each vane of said vanes (18) to a first extent, and at least two shallow portions (19b) arranged to receive each vane of said vanes (18) to a second extent, which is substantially less compared to said first extent, wherein said inner circumferential surface (25) is arranged to receive at least a tip portion of the vanes (18) throughout its whole periphery.