Lifter Assembly Bushing Support for Faster Valvetrain Actuation
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Solution Overview
Problem
Existing engine designs face challenges in fast actuation and oil control of lifter assemblies, particularly in valvetrain systems, which affect valve lift and lower operations.
Innovation Solution
A lifter assembly with an outer body and inner body configuration, featuring an oil port, latch ports, a pin assembly with a bushing and pin, and anti-rotation features to enhance fluid control and prevent rotation, allowing for improved load-bearing and actuation response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a traditional pin assembly is used in the lifter, then the structure is simple, but the pin bends under load and actuation response is slow
Solution Approach 1:
The pin assembly is segmented into multiple functional components: a pin body, a bearing assembly with inner and outer races, rolling elements, and a retainer. This segmentation allows each component to be optimized for its specific function - the bearing assembly handles radial loads to prevent pin bending, while the pin body maintains structural integrity, collectively improving actuation response.
2Reliability
If a bushing is added to support the pin, then pin alignment improves, but device complexity increases
Solution Approach 1:
The bushing is merged with the bearing assembly, where the outer race of the bearing serves as the bushing structure. This integration provides pin alignment and support functions without adding a separate, independent bushing component, thereby improving reliability while minimizing the increase in device complexity.
Solution Approach 2:
The bearing assembly is designed to perform multiple functions simultaneously: it supports the pin radially to prevent bending, provides alignment through the outer race acting as a bushing, and enables smooth actuation through rolling elements. This multi-functionality reduces the need for separate alignment components.
3Use of energy by moving object
If oil control features are added to the bushing, then fluid pressure efficiency improves, but manufacturing complexity increases
Solution Approach 1:
Oil control features such as oil holes and oil grooves are added only to specific localized areas of the bushing where fluid pressure application is most effective. This targeted approach improves fluid pressure efficiency for pin actuation while minimizing the impact on overall bushing manufacturing complexity compared to comprehensive oil control systems.
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
The solution enhances fluid pressure efficiency, reduces pin bending, and improves actuation response by supporting and aligning pins, enabling efficient switching between latched and unlatched positions.
Implementation Method 1
The bushing abuts the inner diameter of the pin passage... configured so that the rim is guided within the bore and is limited by the step
Implementation Method 2
The end wall can comprise a spring seating area. The pin assembly can comprise a spring biased against the spring seating area and the rim
Implementation Method 3
The bushing can be configured with an oil slot to fluidly communicate with the oil passage... enhances fluid pressure efficiency
Data Source
AI summary
A lifter assembly can comprise an outer body comprising an oil port and opposed latch ports. An inner body can comprise a roller assembly or tappet configured to lift and lower to follow a cam. The inner body comprises a pin passage comprising an inner diameter. A pin assembly is mounted in the pin passage. The pin assembly comprises a bushing abutting the inner diameter. The bushing comprises a pin port. A pin comprises a rim and a narrow end configured for sliding in the pin port.