Hydrostatic Rotary Table Feeding Manifold for Eccentric Load Compensation

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Solution Overview

Problem

Hydrostatic rotary tables face tilting issues and reduced precision when handling eccentric or decentred loads due to variable fluid film thickness, leading to potential damage and increased complexity and cost in existing feeding systems.

Innovation Solution

A system with a feeding manifold and adjustable flow rate means, where fluid pressures in each pocket are adjusted sinusoidally based on the load's angular position, maintaining a constant fluid film thickness using a limited number of proportional valves and sensors to control a high number of hydrostatic pockets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If each pocket is fed independently with proportional valves and sensors to compensate for eccentric loads, then the fluid film thickness can be maintained constant, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvefluid film thickness uniformityVSAvoidfeeding system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple pockets into feeding groups, where each group shares common supply and return channels. This merging approach reduces the number of independent control systems needed while maintaining adequate fluid film thickness across all pockets, even under eccentric loads.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a universal feeding manifold that serves multiple pockets simultaneously. The manifold is designed to distribute pressurized fluid to multiple pockets through shared channels, allowing a single control system to manage multiple pockets rather than requiring individual control for each pocket.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a high number of proportional valves and sensors are used to control each pocket individually, then operational precision under eccentric loads is maintained, but constructional and management costs increase

Engineering Contradiction:
Improveoperation reliability under eccentric loadsVSAvoidconstructional cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple pockets into feeding groups with shared fluid channels, reducing the total number of proportional valves and sensors required. This grouping strategy maintains operational reliability by ensuring adequate fluid supply to all pockets while significantly reducing constructional complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies partial control action by using fewer control elements (valves and sensors) than the total number of pockets. The feeding manifold design provides sufficient fluid distribution with less than one control element per pocket, achieving acceptable performance without the excessive complexity of full individual control.

Inventive Principle:
Principle #16Partial or excessive action

3Manufacturing precision

If the fluid pressure is increased to prevent tilting under eccentric loads, then the supporting film thickness is maintained, but the risk of contact and damage to guiding surfaces increases

Engineering Contradiction:
Improvetable level stabilityVSAvoidrisk of guiding surface damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating feeding groups where fluid pressure can be optimized for specific regions. The manifold design allows different sections of the rotary table to receive appropriately pressurized fluid based on local load conditions, maintaining film thickness without requiring uniformly high pressure across all pockets.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces the feeding manifold as an intermediary between the fluid source and individual pockets. The manifold acts as a pressure distribution medium that smooths out pressure variations and prevents localized pressure spikes that could cause guiding surface damage, while still maintaining adequate film thickness.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Ensures precise and reliable operation of hydrostatic rotary tables under eccentric loads by maintaining a constant fluid film thickness, reducing tilting and operational complexity while minimizing constructional and management costs.

Implementation Method 1

the lower fifth wheel is provided with a plurality of hydrostatic pressure pockets, arranged regularly spaced apart along a peripheral circumference of said lower fifth wheel and fed with the pressurised fluid. This fluid, which is typically oil, is forced into each pocket and in a gap created by respective guiding surfaces of said fifth wheels, that face and are opposite one another, so as to form the aforesaid supporting film.

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Increase

Implementation Method 2

each pocket of the lower fifth wheel is fed independently, the oil being supplied at a suitable pressure in function of the eccentricity of the load. The feeding system thus comprises for each pocket at least a proportional valve, or other device suitable for adjusting a pressure and/or a flow rate of the oil

Methodology Applied
Scientific EffectHydraulic pressure control: Pressure Increase

Data Source

PatentEP2067569B1System and method for feeding pressurized fluid to hydrostatic rotary tables
Publication Date: 2010.06.30 PAMA SPA
  • EP2067569B1 patent drawingFigure 1
  • EP2067569B1 patent drawingFigure 2~4
  • EP2067569B1 patent drawingFigure 3~5

AI summary

A system for feeding with a pressurised fluid a hydrostatic rotary table (2) for a machine tool, said hydrostatic rotary table (2) comprising first fifth-wheel means (3) provided with a plurality of hydrostatic pockets (T1, T2, ..., T12) fed with said pressurised fluid for supporting second fifth-wheel means (4) rotating around a rotation axis (B) and arranged for supporting an element (20), comprises a plurality of feeding units (S1, S2, S3) connected to each hydrostatic pocket (T1, T2, ..., T12) by respective hydraulic resistances (R1,1, R1,2, R1,3,..., R12,3), each feeding unit (S1, S2, S3) being arranged for providing said fluid with a respective feeding pressure (P1, P2, P3) that is adjustable in function of an angular position (φ) of said element (20) with respect to a reference axis (X) of said hydrostatic rotary table (2), said element (20) being arranged on said second fifth-wheel means (4) in a decentred manner in relation to said rotation axis (B).