Aircraft Carbon Brake Rear Disc Rivet Structure for Puck Protection
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Solution Overview
Problem
The existing methods for attaching pucks to the rear disc of an aircraft carbon brake system are prone to damage and require delicate positioning, as the rivet insertion process can be challenging and may result in carbon damage during braking.
Innovation Solution
A rivet design with a cylindrical rod and a head featuring a conical base and a circular cylindrical portion is used, where the rivet is inserted through holes in both the rear disc and the puck, with the cylindrical head acting as a guide and increasing the bearing surface to reduce pressure on the carbon, and a fillet connecting the head's surfaces to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional rivet with a head resting on a conical shoulder is used, then the puck can be secured to the rear disc, but the bearing surface is limited and high caulking pressures can damage the carbon
Solution Approach 1:
The rivet head is transformed from a two-dimensional conical base contact to a three-dimensional cylindrical surface contact. The cylindrical portion of the rivet head fits into a cylindrical recess in the rear disc, providing a circumferential bearing surface that distributes pressure around the entire perimeter of the rivet, rather than concentrating it at a single conical contact point.
2Ease of manufacture
If the rivet rod is inserted into a deep hole with a conical shoulder, then the puck can be attached, but positioning the rivet is delicate and difficult
Solution Approach 1:
The cylindrical recess is pre-formed in the rear disc at the correct position and depth. The rivet head's cylindrical portion is designed to fit into this pre-prepared recess, which guides the rivet into proper alignment during insertion. This preliminary preparation of the receiving structure eliminates the need for delicate manual positioning during assembly.
3Reliability
If a conical shoulder hole is used for rivet insertion, then the rivet can be secured, but the rivet head can lose tension and damage the carbon
Solution Approach 1:
The cylindrical recess acts as an intermediary structure between the rivet head and the carbon brake disc. It provides a positive mechanical fit that maintains constant compressive tension on the rivet, preventing the head from lifting or losing tension. The recess walls constrain the rivet head laterally, ensuring continuous contact and force transmission to the carbon disc without allowing excessive movement or tension loss.
Data Source
AI summary
A rear disc of a stack of aircraft carbon brake discs intended to rest against one end of the torque tube of the brake on which the disc stack is threaded, the support being provided by pucks secured to the rear disc by rivets, each inserted into a through hole in the rear disc and a hole opposite one of the pucks. According to the invention, each rivet has a cylindrical rod inserted into the holes of the rear disc and the puck and having an end deformed against the puck, and a head having a circular cylindrical portion with a conical base having an outer peripheral surface connected to a conical surface of the base by a fillet, and the disc through hole has a first portion adapted to receive the rod of the adjusting rivet, a second portion adapted to receive the circular cylindrical portion of the head of the adjusting rivet, and a transition conical portion adapted to receive the conical base of the rivet head.