Motor Case Hub Groove Locking for Secure Shaft Retention
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Solution Overview
Problem
Conventional motor case assemblies face issues with detachment of the shaft due to insufficient connection strength, leading to malfunction and low production yield due to inaccurate laser welding and size precision problems.
Innovation Solution
A motor case assembly design featuring a shaft with a groove and a lower section, where an external force is applied to the hub section to securely connect the shaft with the motor case, enhancing the connection strength and maintaining assembly size stability through a U-shaped or V-shaped annular groove and intrusion mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is used to connect the shaft and motor case, then the connection strength is improved, but the manufacturing precision deteriorates due to difficulty in controlling the welding position within the focusing range
Solution Approach 1:
The patent applies preliminary action by pre-forming a groove structure on the shaft surface before connection. This groove serves as a predetermined positioning feature that guides the hub section during assembly, ensuring the shaft is correctly positioned within the laser welding focusing range before welding occurs. The groove structure is created in advance to prevent positioning errors during the actual connection process.
Solution Approach 2:
The groove structure acts as an intermediary element between the shaft and hub section. It provides a mechanical guide that facilitates accurate positioning of the shaft relative to the hub, enabling the laser welding process to maintain precise focus on the welding position. The groove mediates the interface between components, ensuring proper alignment before the welding action takes place.
2Strength
If laser welding is used to connect the shaft and motor case, then the connection strength is improved, but the production yield deteriorates due to penetration damage when welding position is not accurately controlled
Solution Approach 1:
The groove structure is pre-formed on the shaft to establish a predetermined welding path and positioning reference. This preliminary feature ensures that during assembly and welding, the shaft is automatically positioned within the safe welding focusing range, preventing laser beam penetration damage. The groove structure is created in advance to eliminate positioning variability that causes welding defects.
3Ease of manufacture
If insert injection molding or punching or riveting is used to connect the shaft and hub, then the ease of manufacture is improved, but the connection strength deteriorates when rotational torque exceeds external torque
Solution Approach 1:
The connection structure is segmented into distinct functional zones: the groove structure for positioning and mechanical interlocking, the hub section for providing connection force, and the shaft for rotational function. This segmentation allows each component to perform its specific function optimally, with the groove providing precise positioning and the hub providing sufficient connection strength to resist rotational torque.
Solution Approach 2:
The connection mechanism combines mechanical interlocking (groove structure) with material deformation (intrusion body formed by hub section). This composite approach integrates multiple connection mechanisms - the groove provides structural interlocking while the intrusion body creates metallurgical or plastic bonding, resulting in a connection that can withstand high rotational torques.
4Strength
If the hub section tightly hoops the connection end of the shaft through external force, then the connection strength is improved, but the device complexity increases due to the intrusion mechanism
Solution Approach 1:
The connection structure incorporates dynamic characteristics through the intrusion body mechanism. The hub section is designed to deform plastically under external force, intruding into the groove to create a permanent mechanical lock. This dynamic forming process transforms the connection from a simple fit to a strongly bonded joint, with the deformation occurring during assembly and then stabilizing to provide continuous connection strength.
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 enhanced connection strength prevents shaft detachment and stabilizes the assembly size, increasing production yield and ensuring reliable operation.
Implementation Method 1
The contact sections between an outer circumference of the shaft 12 and the outer side 1111 in adjacency to the perforation 113 are laser welded (or fused) with each other. That is, a laser device 13 is used to generate a laser beam to fuse the outer circumference of the shaft 12 and the outer side 1111 in adjacency to the perforation 113 with each other to form a fusion section 115.
Data Source
AI summary
A motor case assembly includes a shaft and a motor case. The shaft has a connection end formed with a groove. The motor case has a perforation for assembling and connecting with the shaft. A hub section protrudes a rim of the perforation and has a forced outer face and an inner face surrounding the connection end and the groove of the shaft. An external means is used to apply an external force to the hub section so as to make the hub section tightly hoop the connection end of the shaft. By means of the external force, the inner face of the hub section is partially intruded into the groove of the shaft to form an intrusion body connected with the groove under a top wall inner face of the motor case. Therefore, the motor case and the shaft are securely connected with each other without easy detachment.