Rocker Arm Grading Tool for Valve Lift Control
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Solution Overview
Problem
Roller rocker arms experience tolerance stack-up issues, leading to variations in valve lift, which can result in unstable engine performance, increased scrap rates, and high manufacturing costs due to the need for precise machining techniques.
Innovation Solution
A rocker arm grading system with a grading tool that includes a rocker arm jig, cam jig, and measuring devices to precisely measure the roller bearing position, allowing for sorting of rocker arms into grades to minimize valve lift variation, using a pivot peg, valve peg, cam pin, and wavelength emitting/detecting devices to determine the radius and distances, thereby controlling valve lift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If more precise manufacturing and machining techniques are used to reduce variation in the roller rocker arm, then manufacturing precision is improved, but manufacturing cost increases and scrap volume increases
Solution Approach 1:
The patent applies preliminary action by measuring and grading rocker arms during manufacturing before assembly. The grading tool measures the bearing surface radius and calculates valve lift values, allowing rocker arms to be sorted into different grades (A, B, C, D) based on their actual dimensions. This preliminary measurement and classification enables the use of standard manufacturing processes while still achieving precise control over final product variation through selective assembly.
2Manufacturing precision
If more precise manufacturing and machining techniques are used to reduce variation in the roller rocker arm, then manufacturing precision is improved, but scrap volume increases
Solution Approach 1:
The patent applies discarding and recovering by sorting rocker arms into different grades rather than discarding those outside tight tolerances. The grading system categorizes rocker arms by their measured bearing surface radius into groups (A: 0.00-0.02mm, B: 0.02-0.04mm, C: 0.04-0.06mm, D: 0.06-0.08mm deviation), allowing all parts to be utilized in appropriate applications. This recovers potentially usable components that would otherwise be scrapped, reducing material loss while maintaining manufacturing precision through selective matching.
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 system achieves precise control of roller rocker arm assembly positional tolerance, reducing valve lift variation by up to ±0.02 mm, enabling cost-effective sorting and matching of rocker arms to specific engine requirements, improving engine stability and reducing manufacturing expenses.
Implementation Method 1
At least one measuring device comprising a wavelength emitting device paired with a wavelength detecting device can be configured to measure the radius of the bearing surface with respect to the pivot peg
Data Source
AI summary
A rocker arm grading system can comprise a grading tool. The grading tool can be used with a rocker arm to measure aspects of the rocker arm and determine a resulting valve lift. The grading tool can comprise a rocker arm jig comprising a pivot peg and a valve peg. A cam jig can comprise a cam arm. A cam pin can be mounted in the cam arm. A rocker arm can be removably mounted to the rocker arm jig. The rocker arm can comprise a radius on a bearing surface. A cam edge of the cam pin can press against the bearing surface. At least one measuring device comprising a wavelength emitting device paired with a wavelength detecting device can be configured to measure the radius of the bearing surface with respect to the pivot peg.