Tubular shaft splicing device capable of transmitting torque
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Solution Overview
Problem
Existing tubular shaft splicing devices face challenges in transmitting high torques without deformation and play, especially when connecting tubular shafts with round cross-sections, due to concentration of loads and risk of local deformation from cylindrical bolts or rivets.
Innovation Solution
The use of passing-through locking members with a rectangular or trapezium cross-section and conjugated locking holes reduces surface stress concentration by increasing contact surface area, and pairs of shaft and plate locking holes with U-shaped locking elements ensure secure torque transmission without play.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical bolts or rivets with circular holes are used to connect tubular shaft stretches, then the splicing device can be manufactured with simple geometry, but the contact between bolts and shaft is limited to specific points causing concentration of loads and local deformations
Solution Approach 1:
The patent changes the geometric parameters of the locking members from cylindrical to rectangular or trapezium cross-section, and the holes from circular to rectangular. This parameter change transforms the contact from point contact to surface contact, distributing loads over a larger area and preventing local deformations while maintaining manufacturing feasibility.
Solution Approach 2:
The patent applies local quality by creating different contact characteristics in different regions. The rectangular or trapezium cross-section of locking members provides extended contact surfaces at critical stress points, while the overall structure maintains simplicity. This localized geometric modification addresses stress concentration without complicating the entire design.
2Reliability
If a large number of cylindrical bolts or rivets are used to avoid local deformations, then stress distribution improves, but the device complexity and number of components increases
Solution Approach 1:
By changing the cross-sectional geometry of locking members to rectangular or trapezium, the patent achieves better stress distribution with fewer components. The extended contact surfaces of the non-circular geometry provide improved load distribution, reducing the number of locking members needed compared to cylindrical bolts.
Solution Approach 2:
The rectangular or trapezium locking members serve multiple functions: they provide mechanical connection, distribute loads over extended surfaces, prevent relative rotation between shaft stretches, and maintain structural alignment. This multi-functionality reduces the need for additional specialized components.
3Power
If splicing plates are pressed against end portions of tubular shaft stretches, then torque transmission is enabled, but deformation of splicing plates may occur leading to play or relative rotation under torsional stresses
Solution Approach 1:
The patent changes the cross-sectional geometry of locking members from cylindrical to rectangular or trapezium, creating extended contact surfaces that distribute torsional stresses more evenly across the splicing plates and shaft ends. This geometric modification prevents stress concentration and reduces deformation under torque loads.
Solution Approach 2:
The rectangular or trapezium cross-section introduces asymmetric geometry that provides superior mechanical interlocking and stress distribution compared to symmetric cylindrical shapes. The non-circular geometry creates inherent resistance to rotation and deformation, enhancing the strength of the splicing connection under torsional loads.
Data Source
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AI summary
The tubular shaft splicing device comprises adjacent first and second end portions (11, 21) of two tubular shaft stretches (10, 20), one or more splicing plates (30, 40) superimposed to opposite sides of the first and second end portions (11, 21) of the tubular shaft stretches, and passing-through locking members (51, 52) inserted in aligned locking holes (13, 14; 23, 24; 33, 34; 43, 44) formed in the first and second end portions (11, 21) of the tubular shaft stretches (10, 20) and in the one or more splicing plates (30, 40). The passing-through locking members have a rectangular or trapezium cross-section and the locking holes formed in the first and second end portions of the tubular shaft stretches and in the one or more splicing plates have a conjugated rectangular or trapezium shape, with two sides of the rectangular or trapezium shape being parallel to a longitudinal axis of the tubular shaft.