Multi-part Roller Tappet Guide Cylinder Constriction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-part roller tappets face challenges in maintaining the outer geometry and dimensions of the guide cylinder when attaching a cup-shaped sleeve, and they are not easily adaptable to varying installation lengths and distances between the camshaft and pump element, leading to increased moving mass and potential deformation.
Innovation Solution
A multi-part roller tappet design featuring a guide cylinder with a cylindrical constriction and a constriction groove allows for precise attachment of the cup-shaped sleeve without altering the guide cylinder's geometry, enabling adaptation to different lengths and accommodating thermal and component-induced deformations through a press-fit joint that maintains the outer dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wall thickness of the guide cylinder is increased to avoid deformation during attachment, then the structural strength is improved, but the moving mass of the roller tappet increases
Solution Approach 1:
The guide cylinder features a localized constriction region with reduced wall thickness positioned at the attachment area, while the rest of the cylinder maintains sufficient wall thickness for strength. This local modification allows the cup-shaped sleeve to be attached without requiring the entire cylinder to have increased wall thickness, thus avoiding unnecessary mass increase while maintaining structural integrity.
2Stability of the object's composition
If the cup-shaped sleeve is attached axially outside the constriction, then the constriction region is protected from deformation, but the attachment location is restricted and may not be suitable for all installations
Solution Approach 1:
The guide cylinder is segmented into distinct functional regions: a constriction region with reduced wall thickness for attachment, and a main body region maintaining original dimensions. The constriction groove is stamped inside the constriction to provide a precise attachment location that protects the constriction region while allowing flexible installation configurations.
3Measurement precision
If the guide cylinder is made with precise fit in the housing receptacle, then the guidance precision is improved, but the susceptibility to thermal and component-induced deformations increases
Solution Approach 1:
The guide cylinder incorporates a constriction with specific dimensional parameters that allow controlled expansion during operation. This constriction acts as a deformation absorption zone that accommodates thermal and component-induced changes while maintaining the precise fit in the housing receptacle, thus protecting the overall guidance precision.
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 ensures precise fit and adaptability, preventing deformation in the guide cylinder while allowing for expansion without increasing friction, thus maintaining the component's stiffness and preventing seizing in the housing receptacle.
Implementation Method 1
the radial ring of the cup-shaped sleeve is attached to the inner casing of the constriction groove
Implementation Method 2
the guide cylinder has a cylindrical constriction, a constriction groove is stamped inside the constriction of the guide cylinder
Implementation Method 3
irrespective of thermal and component-induced deformations
Data Source
AI summary
A roller tappet, in particular for a high-pressure fuel pump, is provided that is guided in the direction of the longitudinal axis thereof in a housing receptacle and is driven translatably in the longitudinal direction by cams of a camshaft. The roller tappet has a tappet body. This tappet body has a tappet skirt, a pump piston contact point (9), and a rotatably mounted roller (4), by which the roller tappet is supported on the camshaft. The tappet body has a guide cylinder (1), which is mounted in the housing receptacle and on which the roller (4) is supported, and a cup-shaped sleeve (7) having the pump piston contact point (9), which cup-shaped sleeve is supported in the guide cylinder (1) by a radial ring (8). A cylindrical constriction (5) is formed in the guide cylinder (1) in the region of the radial ring support.