Cam Follower Retaining Member Eliminates Pin Caulking
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Solution Overview
Problem
The caulking process for assembling cam followers is costly and time-consuming, which is a significant drawback in the manufacturing of mechanical systems like injection pumps and valve actuators.
Innovation Solution
A mechanical system comprising a support element with a pin and a roller, where a retaining member blocks the translation of the pin, eliminating the need for caulking and providing an external guiding surface for sliding, and is assembled using adhesive means or fretting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pin ends are caulked to secure the pin in the tappet bores, then the mechanical connection is strong and reliable, but the manufacturing cost increases and the assembly time is extended
Solution Approach 1:
The invention extracts the caulking operation from the assembly process by using a retaining member that mechanically blocks pin translation without requiring plastic deformation of the pin ends. The retaining member's blocking geometry provides the securing function previously achieved through caulking, eliminating the time-consuming deformation step.
Solution Approach 2:
The retaining member acts as an intermediary element between the pin and the tappet bores. Instead of directly securing the pin through caulking, the retaining member mediates the connection by providing a geometric barrier that prevents pin displacement, thereby achieving reliable mechanical connection without the harmful caulking process.
2Strength
If the pin ends are caulked to create a mechanical connection, then the pin is securely retained in the tappet, but the manufacturing cost and assembly time increase
Solution Approach 1:
The invention removes the caulking step from the assembly sequence by employing a retaining member with blocking geometry that inherently secures the pin. The blocking features (such as protrusions fitting into recesses or geometric interlocking) provide the necessary retention strength without requiring time-consuming plastic deformation operations.
Solution Approach 2:
The retaining member is designed with pre-formed blocking geometry that automatically secures the pin upon assembly. This preliminary geometric configuration eliminates the need for subsequent caulking operations, as the retention function is already built into the retaining member's structure before assembly occurs.
3Productivity
If a retaining member is used instead of caulking to block pin translation, then the assembly time and cost are reduced, but additional components are required
Solution Approach 1:
The retaining member is merged with the tappet structure in many embodiments, where the retaining features are integrated into the tappet body or flanges rather than being separate components. This merging approach provides the pin-blocking function while minimizing the number of discrete parts, thereby reducing assembly complexity despite eliminating caulking.
Solution Approach 2:
The retaining member serves multiple functions: it blocks pin translation, provides guiding surfaces for the mechanical system, and in some embodiments, acts as a structural element of the tappet. This multi-functionality justifies the addition of the retaining member by consolidating several functions into a single component rather than requiring multiple separate parts.
Data Source
AI summary
A mechanical system forming one of a cam follower or a rocker arm, the mechanical system comprising: a support element, a pin extending between two opposite ends along a first axis and supported by the support element, and a roller mounted on pin, movable in rotation relative to the pin around the first axis and adapted to roll on a cam. The support element includes a bearing body adapted to receive pin, and an additional retaining member blocking the translation of pin back and forth, along first axis.