Segmented Transmission Wheel Press Fit for In-Situ Shaft Mounting
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Solution Overview
Problem
In the wood-processing industry, especially with large conveyors, mounting new transmission wheels on a shaft in situ is challenging due to exposure to elements and abrasive materials, requiring segmented wheels that achieve a tight press fit without damaging the shaft and ensuring reliable torque transmission, especially when the shaft cannot be removed.
Innovation Solution
A segmented transmission wheel design where the segments are welded together with a press fit, using incomplete sectors to minimize gap width and prevent end face contact, allowing for a strong shrink fit without keys and enabling easy replacement and maintenance, utilizing arc-welding to create a durable joint that can be ground out when worn.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the transmission wheel is divided into segments for in-situ mounting, then the ease of installation is improved, but the reliability of torque transmission deteriorates due to difficulty in achieving tight press fit
Solution Approach 1:
The transmission wheel is divided into multiple segments that can be mounted separately on the shaft in-situ. Each segment is designed with precise dimensions to achieve proper alignment and fit when assembled together on the shaft, enabling installation without removing the shaft from the machine.
Solution Approach 2:
The invention changes the physical state of the segments through thermal expansion and contraction during mounting. The segments are heated to expand their inner diameter for easier assembly, then cooled to contract and create a tight press fit on the shaft, ensuring reliable torque transmission.
2Strength
If arc-welding is used to join segments, then the strength of the joint is improved due to shrinkage force, but the risk of damaging the shaft surface increases
Solution Approach 1:
The invention introduces a sacrificial backing plate or shield between the welding arc and the shaft surface. This intermediary component absorbs the heat and spatter from arc-welding, protecting the shaft surface from damage while allowing the segments to be strongly joined together.
Solution Approach 2:
The invention creates a replica or model of the welding process using a test segment or sample first. By practicing the welding technique on a copy or test piece, the optimal parameters and protective measures can be established before performing the actual welding on the transmission wheel segments, preventing shaft surface damage.
3Reliability
If keys and keyways are used for torque transmission, then the reliability of power transmission is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts and eliminates the key and keyway components from the traditional power transmission design. Instead of using mechanical keys, the segments are directly pressed onto the shaft with sufficient friction and normal force to transmit torque, simplifying the structure and reducing manufacturing complexity.
Solution Approach 2:
The invention replaces the mechanical key-way system with a friction-based press fit system. The normal force from the press fit creates sufficient friction to transmit torque, substituting a simpler mechanical arrangement for the more complex keyed connection.
4Manufacturing precision
If the segments are made as complete sectors, then the manufacturing precision is improved, but the gap control between segments deteriorates
Solution Approach 1:
The invention introduces asymmetric features such as tapered edges or non-uniform gap distribution between segments. This asymmetry allows for controlled gap formation during assembly, enabling precise gap control while maintaining high manufacturing precision of individual segment components.
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 solution ensures a reliable, durable, and maintainable transmission wheel assembly that transmits full torque without keys, allowing for efficient replacement and minimizing manufacturing and maintenance costs by avoiding keyway creation and ensuring consistent power transmission.
Implementation Method 1
Arc-welding is a particularly advantageous joining method because the residual stresses of a wide weld shrink the joint and cause a particularly great force shrinking the gap left in the joint.
Implementation Method 2
the residual stresses of a wide weld shrink the joint and cause a particularly great force shrinking the gap left in the joint
Implementation Method 3
a press fit can transmit the entire load without a key
Data Source
Figure 1
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AI summary
A transmission wheel assembled of at least two segments (1) on a shaft (12), the inner arc surface (3) of which and the shaft (12) have essentially the same radius (R), and which segments' (1) outer surfaces (9) have profiled surfaces that transmit the power of the transmission wheel. Between the segments' (1) welded-together end faces (4) there are gaps on those sections of the end faces (4) that are not welded, which creates a press fit between the shaft (12) and the inner arc surface (3) of the transmission wheel. The weld connecting the transmission wheel segments' (1) end faces (4) is preferably incomplete, meaning that it does not reach the shaft (12).