Cam Follower Roller Insert Fixation via Centring Parts

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Solution Overview

Problem

Existing cam follower roller devices have complex assembly processes, which hinder efficient and simplified installation in applications like fuel injection pumps and rocker systems for internal combustion engines.

Innovation Solution

The cam follower roller device features a tappet body with abutting means and centring parts that axially support and radially centre an insert, along with retaining means formed by local plastic deformation to securely hold the insert and pin, simplifying assembly by reducing the axial distance and using symmetrical lugs and pins for alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional punching methods are used to fix the insert to the tappet housing, then the insert can be secured, but the assembly process becomes complex and time-consuming

Engineering Contradiction:
Improveinsert fixationVSAvoidassembly process
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the complex two-directional punching process and replaces it with a simplified retaining means system. The insert is secured using retaining means formed on the tappet housing that engage with corresponding features on the insert, eliminating the need for complex punching operations in both radial and axial directions while maintaining secure fixation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the fixation mechanism from mechanical punching (permanent deformation) to a retaining means system that uses controlled deformation and engagement features. This parameter change allows for simpler assembly while maintaining the reliability of insert fixation through proper engagement geometry and material selection.

Inventive Principle:
Principle #35Parameter changes

2Strength

If multiple punching operations are performed to secure the insert, then the insert is firmly fixed, but the manufacturing time and complexity increase

Engineering Contradiction:
Improveinsert fixation strengthVSAvoidassembly speed
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The retaining means are pre-formed on the tappet housing during manufacturing, so that during assembly, the insert simply needs to be positioned and the retaining means engage with it. This preliminary preparation eliminates the need for multiple punching operations during assembly, maintaining strong fixation while significantly improving assembly speed and productivity.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the insert is mounted without centring features, then the assembly is simpler, but the radial alignment precision deteriorates

Engineering Contradiction:
Improveassembly simplicityVSAvoidradial centre alignment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces centring features as intermediary elements between the tappet housing and the insert. These centring features guide the insert into proper radial alignment during assembly, ensuring precise positioning without requiring complex alignment procedures or additional adjustment steps, thus maintaining both simplicity and precision.

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

This design significantly simplifies the assembly process by providing a secure and precise mounting system for the insert and pin, enhancing the overall efficiency and reliability of the device in automotive and industrial applications.

Implementation Method 1

retaining means formed by local plastic deformation to axially retain the insert relative to the tappet housing

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3121436B1Cam follower roller device and associated manufacturing method
Publication Date: 2018.05.02 AB SKF SKF PATENT DEPARTMENT
  • EP3121436B1 patent drawingFigure 1~2
  • EP3121436B1 patent drawingFigure 3~4
  • EP3121436B1 patent drawingFigure 5

AI summary

The cam follower roller device comprises a tappet body 12 extending along an axis, an insert 18 mounted in said body, a pin 14 mounted at least on said insert, and a roller 16 mounted on said pin. The tappet body 12 comprises abutting means 22 extending from an inner surface 12c of said body and at least one centring part 26 protruding axially form said abutting means. The insert 18 is mounted axially against said abutting means 22, 24 and comprises at least one hole 46 inside which said centring part 26 extends. Retaining means 60 are provided on said centring part to axially retain the insert 18 against said abutting means.