Composite Cradle Bearing Assembly for Low-Noise Swash Plate Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing roller cradle bearing assemblies for hydraulic axial piston units are costly and difficult to manufacture, with issues of swash plate bending, vibration, and noise due to the complexity and high tooling demands of metal components.
Innovation Solution
The cradle bearing assembly uses plastic or composite material for the ring-segments, with metal races embedded within, allowing for simpler geometric designs and reduced manufacturing costs through injection molding or 3D printing, and a timing mechanism to manage roller movement, distributing load and reducing friction and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal components are used for cradle bearing assembly, then strength and load-bearing capacity are improved, but manufacturing cost and tooling complexity increase
Solution Approach 1:
The patent employs composite construction by embedding metal races within plastic or composite material bodies. The metal races provide necessary strength and load-bearing capacity at contact points, while the plastic bodies reduce overall weight and manufacturing complexity. This composite approach resolves the contradiction by combining materials with complementary properties to achieve both high strength and cost-effectiveness.
Solution Approach 2:
The invention applies local quality by using metal only where structurally necessary - specifically at the raceways that contact rollers and bear loads. The non-critical portions of the ring-segments are made from cheaper plastic materials. This localized material selection optimizes the strength-to-cost ratio by concentrating expensive metal material only where mechanical performance is critical.
2Reliability
If hardened running surface is applied on swash plate, then wear resistance is improved, but manufacturing complexity and processing difficulty increase
Solution Approach 1:
The patent extracts the hardened running surface function from the swash plate itself and relocates it to separate, replaceable liner components. This allows the swash plate to remain simple and easy to manufacture, while the extracted liner components can be independently hardened or treated for wear resistance. This separation resolves the contradiction by removing the complex hardening process from the main swash plate manufacturing flow.
Solution Approach 2:
The invention changes the material parameter of the running surface from hardened metal (on swash plate) to alternative materials such as plastic composites or coated surfaces on liners. This parameter change allows achieving wear resistance through material selection rather than through complex thermal or chemical hardening processes, thereby reducing manufacturing complexity while maintaining reliability.
3Loss of energy
If unitized roller cradle bearing assembly is used, then friction is reduced, but device complexity and assembly difficulty increase
Solution Approach 1:
The patent segments the cradle bearing assembly into modular components: inner and outer ring-segments with embedded races, roller elements, and timing mechanisms. This segmentation allows each component to be manufactured and pre-assembled separately with optimized tolerances, reducing friction through precise fitting, while the modular nature simplifies final assembly and maintenance. The segmentation resolves the contradiction by enabling low-friction precision interfaces without requiring complex monolithic construction.
4Ease of manufacture
If plastic or composite material is used for ring-segments, then manufacturing cost is reduced, but load distribution capability may be compromised
Solution Approach 1:
The patent uses composite construction where plastic or composite material bodies are combined with embedded metal races. The plastic bodies provide cost-effective manufacturing and adequate load distribution over large areas, while the embedded metal races concentrate and handle high contact stresses at roller interfaces. This composite approach resolves the contradiction by allowing plastic materials to perform their strength function where applicable while using metal only where high contact strength is required.
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 solution reduces manufacturing costs, minimizes swash plate bending, and enhances durability by using composite materials for pressure distribution and damping, resulting in lower vibration and noise while maintaining stable support with a greater axial length-diameter ratio of rollers.
Implementation Method 1
The races on which the rollers run can thus simply be formed as a metal band, e.g. a pre-curved or planar steel band bent into final curvature when assembled to the respective inner or outer body of the respective ring-segment. Thus, the inner and outer ring-segments of the cradle bearing assemblies according to the invention are composite parts, wherein the geometric complex function is assumed by the plastic or composite reinforced plastic part and the heavy loaded function is assumed by metal parts of simple standard geometry.
Implementation Method 2
The plastic or composite material body is used for assembly, mounting tabs, and a timing mechanism while the metal races evenly distribute the load from the roller to the inner and outer plastic bodies which in turn dampen and distribute the load to the housing and the swash plate cradle surface, respectively.
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A bearing assembly having a metallic inner race, a metallic outer race, and a plurality of rollers positioned between the inner race and the outer race. A pad of non-metallic material is attached to the inner race and a bed of non-metallic material is attached to the outer race. A timing mechanism is mounted to the pad and the bed. Preferably the pad and bed are made of plastic and the inner race is embedded within the pad and the outer race is embedded within the bed.