Radial Piston Pump Cover Retention Using A Single Retaining Ring

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Solution Overview

Problem

Existing radial piston pumps require multiple screws for securing covers, which increases assembly complexity, cost, and space requirements, and lacks efficient methods for cover retention under high pressure differentials.

Innovation Solution

A radial piston pump design utilizing a single retaining ring to secure all covers, combined with a housing that integrates the retaining ring, reducing the need for screws and simplifying assembly by using a press fit or thermal expansion for secure cover retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple screws are used to secure covers, then the cover is securely fastened under high pressure differentials, but the assembly complexity and manufacturing cost increase

Engineering Contradiction:
Improvecover retentionVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple screw connections for securing covers are merged into a single retaining ring component that circumferentially retains all covers, reducing the number of fastening elements from multiple screws to one integrated ring structure

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The retaining ring serves multiple functions simultaneously: it acts as a single fastening element replacing multiple screws, provides circumferential retention for all covers, and maintains seal integrity under pressure differentials through its continuous circular structure

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

2Reliability

If multiple screws are used to secure covers, then the cover is securely fastened, but the manufacturing cost increases due to additional parts and machining

Engineering Contradiction:
Improvecover retentionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple separate screw fastenings are combined into a single retaining ring component, reducing the total number of parts that need to be manufactured, inventoried, and assembled

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The complex screw connection system with multiple fastening points is extracted and replaced by a simpler retaining ring mechanism that achieves the same retention function with fewer components and less machining

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If multiple screws are used to secure covers, then the cover is securely fastened, but the radial space requirement increases

Engineering Contradiction:
Improvecover retentionVSAvoidradial space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

Multiple distributed screw connections are merged into a single circumferential retaining ring that provides continuous retention around the cover perimeter, eliminating the need for multiple discrete fastening points that would require radial space

Inventive Principle:
Principle #5Merging (Combining)

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 reduces component count, eliminates costly machining and assembly steps, and enhances assembly efficiency while maintaining cover position under high pressure differentials, thereby lowering manufacturing costs and improving design flexibility.

Implementation Method 1

A radial piston pump design utilizing a single retaining ring to secure all covers, combined with a housing that integrates the retaining ring, reducing the need for screws and simplifying assembly by using a press fit or thermal expansion for secure cover retention.

Methodology Applied
Scientific EffectPress fit:

Implementation Method 2

A radial piston pump design utilizing a single retaining ring to secure all covers, combined with a housing that integrates the retaining ring, reducing the need for screws and simplifying assembly by using a press fit or thermal expansion for secure cover retention.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

When the piston moves from the upper end position to the lower end position, a vacuum is created in the working chamber between the piston head and the cover, and the inlet valve opens into the working chamber, drawing in fresh gas.

Methodology Applied
Scientific EffectVacuum creation:

Implementation Method 4

After the piston reaches bottom dead center (BDC), the piston moves upwards again, the inlet valve closes, and the fluid, particularly gas, in the working chamber is compressed. In CO2 compressors, for example, the pressure in the working chamber rises to up to 140 bar.

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4337860B1Radial piston pump, and process for manufacturing a radial piston pump
Publication Date: 2025.09.17 THYSSENKRUPP DYNAMIC COMPONENTS GMBH
  • EP4337860B1 patent drawingFigure 1a~1b
  • EP4337860B1 patent drawingFigure 2~3
  • EP4337860B1 patent drawingFigure 4~5

AI summary

The invention relates to a radial piston pump comprising a drive shaft (1) with an eccentric (11), and comprising at least one piston-working chamber combination (2), the piston-working chamber combination (2) comprising a working chamber (21) and a piston (22). The radial piston pump comprises at least two piston-working chamber combinations (2, 2a, 2b,…) which extend radially from the drive shaft (1), each working chamber (21) being closed by a cover, the radial piston pump being equipped with at least one retaining ring for fastening all of the covers of the radial piston pump. The invention also relates to a process for manufacturing a radial piston pump.