Cam Follower Roller Pin Local Tempering for Caulking
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Solution Overview
Problem
The existing surface induction hardening method for cam follower roller device pins is expensive and results in hardness heterogeneity, limiting the ability to effectively caulk pin ends for secure mechanical connection with the tappet body.
Innovation Solution
A through-hardening and local tempering method is applied, where the entire pin is hardened and then only the pin ends are tempered to reduce their hardness, allowing for caulking and reducing production costs while maintaining necessary hardness for the central portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface induction hardening is applied to the pin, then the central portion hardness is improved, but the manufacturing cost increases and hardness heterogeneity occurs
Solution Approach 1:
The patent applies local tempering to the pin ends after through-hardening, creating different hardness zones: the central portion maintains high hardness for wear resistance, while the pin ends are locally tempered to reduce hardness for caulking operations. This resolves the contradiction by achieving the required hardness distribution without expensive surface induction hardening.
Solution Approach 2:
The patent changes the tempering temperature parameter locally: the central portion is tempered at a lower temperature to maintain hardness, while the pin ends are tempered at a higher temperature to reduce hardness for caulking. This parameter differentiation eliminates the need for expensive surface hardening while achieving the desired hardness distribution.
2Strength
If surface induction hardening is applied to the pin, then the central portion hardness is improved, but hardness heterogeneity is generated
Solution Approach 1:
The patent deliberately creates local quality differences through controlled tempering: the central portion is tempered at lower temperature to maintain high hardness, while pin ends are locally tempered at higher temperature to reduce hardness. This controlled heterogeneity achieves both wear resistance and caulking capability, resolving the contradiction between hardness improvement and uniformity requirements.
Solution Approach 2:
The patent segments the pin into two functional zones with different hardness requirements: the central portion for wear resistance and the pin ends for caulking. Through selective tempering, each zone receives appropriate heat treatment, achieving the desired hardness distribution without the heterogeneity problems of surface induction hardening.
3Ease of manufacture
If the entire pin is hardened, then the manufacturing cost is reduced, but the pin ends cannot be effectively caulked
Solution Approach 1:
The patent applies local tempering to the pin ends after through-hardening, creating different hardness zones: the central portion maintains high hardness for wear resistance, while the pin ends are locally tempered to reduce hardness for caulking operations. This resolves the contradiction by achieving the required hardness distribution without expensive surface induction hardening.
Solution Approach 2:
The patent performs through-hardening of the entire pin first, then applies preliminary local tempering to the pin ends before caulking operations. This sequence ensures the pin ends have the appropriate hardness for effective caulking while maintaining the cost advantage of through-hardening.
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 method enables cost-effective production of pins with secure mechanical connection to the tappet body, reducing hardness heterogeneity and enhancing the mechanical stability of the cam follower roller device.
Implementation Method 1
applying a through-hardening treatment and a through-tempering treatment to obtain the pin with a predetermined hardness
Implementation Method 2
applying a local tempering treatment in which only pin ends of the hardened pin are tempered in order to reduce the hardness of said pin ends relative to the hardness of the remainder of the pin
Implementation Method 3
the pin ends may be tempered with induction heating during the local tempering treatment step
Data Source
Figure 1
Figure 2~3
AI summary
The method for manufacturing a pin (14) for cam follower roller device (10) comprises the following successive steps of: - applying a through-hardening treatment (102) and a through-tempering treatment to obtain the pin (14) with a predetermined hardness, and - applying a local tempering treatment in which only pin ends (14b, 14c) of the hardened pin (14) are tempered in order to reduce the hardness of said pin ends (14b, 14c) relative to the hardness of the remainder of the pin.