Radial Piston Unit Housing Layout for Shorter Axial Length

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Radial piston units, particularly cam lobe and orbital motors, face challenges in reducing external dimensions, especially axial dimensions, while maintaining performance and operational characteristics, and require improvements in robustness, manufacturing costs, maintenance, and operational flexibility.

Innovation Solution

A hydrostatic radial piston unit design featuring a single-piece rear case with integrally formed annular flow passages and axial distribution channels, eliminating the need for a separate distributor element and seals, allowing for a more compact and flexible design by moving these components radially outward, which reduces axial length and manufacturing complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a separate distributor element is used to form annular flow passages and distribution conducts, then the hydraulic connections are achieved, but the axial length and device complexity increase

Engineering Contradiction:
Improveaxial lengthVSAvoidnumber of separate parts
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the distributor element with the rear case part into a single integrally formed component. The rear case part now directly forms both the annular flow passages and the distribution conducts that connect to timing holes, eliminating the need for a separate distributor element and reducing axial length while maintaining hydraulic functionality

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If multiple separate components (rear case part and distributor element) are used, then manufacturing is simplified, but assembly complexity and seal requirements increase

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

By integrating the distribution conducts and annular flow passages into the rear case part as a single component, the patent eliminates the need for assembly between separate distributor and case parts, removing seal requirements and simplifying both manufacturing and assembly processes

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If the distributor element is positioned radially inward, then space is saved, but the timing holes connection becomes more complex

Engineering Contradiction:
Improvespace utilizationVSAvoidconnection complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent redistributes the hydraulic pathways by having distribution conducts extend radially outward from the central axis to reach timing holes positioned on the periphery, utilizing radial space efficiently while maintaining simple axial connections through the cylinder block front face

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 operational flexibility, reduces wear, and improves controllability, while minimizing manufacturing and assembly costs, achieving a more compact and robust radial piston unit with reduced axial length and increased freedom of design.

Implementation Method 1

internal annular flow passages which are running in circumferential direction around the centre axis and are configured to be hydraulically connected to an inlet and an outlet of the radial piston unit. The internal annular flow passages are further connected to generally axial oriented internal distribution conducts

Methodology Applied
Scientific EffectHydraulic fluid flow: Hydraulic Press

Data Source

PatentEP4208639B1Hydrostatic radial piston unit
Publication Date: 2024.01.17 DANFOSS POWER SOLUTIONS (JIANGSU) CO LTD
  • EP4208639B1 patent drawingFigure 1~2
  • EP4208639B1 patent drawingFigure 3~4
  • EP4208639B1 patent drawingFigure 5

AI summary

Hydrostatic radial piston unit comprising a front case part accommodating a drive shaft via shaft bearing means so that the drive shaft can rotate around a central axis relative to the front case part. A rear case part is attached on one side to the front case part and closed on another side in order to define an internal volume. A cylinder block is disposed in the internal volume and attached to the drive shaft in a torque proof manner. Axially disposed timing holes in the cylinder block connect radially oriented working volumes in the cylinder block with a cylinder block front face that is arranged perpendicularly to the central axis and faces away from the front case part. Integrally within the rear case part internal annular flow passages are formed and are connected to an inlet and an outlet of the radial piston unit and running basically in circumferential direction around the central axis. Internal distribution conducts configured to hydraulically connect the internal annular flow passages with the cylinder block timing holes are integrally formed within the rear case part, too.