Tripod CV Joint Journal Forging with Centering Edge
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Solution Overview
Problem
The manufacturing of tripod-type constant-velocity universal joints faces challenges in centering journal raw profiles due to difficulties in forming precise leading end corner portions, leading to increased weight, manufacturing steps, and costs, as well as complex forging conditions.
Innovation Solution
A method involving the use of a die with a relief portion at the leading end of the journal raw profile to hold and forge the journal, allowing it to adhere to the die's inner walls and form edge portions as centering references, reducing the need for additional turning and burring steps and simplifying the forging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional forging method is used to form journal raw profiles, then journals can be manufactured, but leading end corner portions cannot be precisely formed requiring additional turning and burring steps
Solution Approach 1:
The die is designed with pre-formed edge portions at the leading end corner of the journal raw profile that create centering references during forging. This preliminary formation of centering features eliminates the need for subsequent turning and burring operations to create these references, directly resolving the contradiction between precision and productivity.
2Manufacturing precision
If journal raw profile is enlarged to accommodate turning operations, then centering references can be formed, but weight of the component increases
Solution Approach 1:
Instead of uniformly enlarging the journal raw profile, the invention applies local quality by forming precise edge portions only at the leading end corner portions where centering references are needed. This localized approach maintains minimal material while achieving the required centering precision, eliminating the need for overall profile enlargement.
3Manufacturing precision
If strict forging conditions are imposed to form precise leading end corners, then centering references can be created, but forging process becomes complex
Solution Approach 1:
The die design incorporates self-service by including pre-formed edge portions that automatically create accurate centering references during the normal forging process. The forging operation itself generates the precise leading end corners without requiring additional control measures or complex forging conditions, as the die structure performs the centering reference formation function.
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 approach reduces the weight and number of manufacturing steps, lowers manufacturing costs, and facilitates the forging process by eliminating the need for strict forging conditions and subsequent centering reference formation, while ensuring reliable centering through edge portions formed during forging.
Implementation Method 1
a journal raw profile is forged with use of a die, in a state in which a relief portion is provided on a leading end side of the journal raw profile with use of the die
Data Source
AI summary
A tripod-type constant-velocity universal joint has a journal raw profile with reduced weight and a reduced number of manufacturing steps. A leading end corner portion of the journal raw profile is held with use of a die and forged. By the forging, at the part including an elliptically longitudinal side relatively on a leading end portion side of an outer peripheral surface of each of journals, edge portions reducing a lateral sectional area of each of the journals toward a leading end side thereof are formed, and tapered surfaces are formed on the leading end side of the edge portions. Centering on each of the journals is performed by causing two points on an elliptically longitudinal side of the edge portions to abut against a centering jig.