Differential Case Welding Fixation via Circular Groove
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Solution Overview
Problem
Existing differential gear set assembly methods require complex structures for fixation by welding, leading to increased working costs and reduced accuracy.
Innovation Solution
A differential gear set case design that includes a carrier, cover, and ring gear, where the components are united by welding through a circular groove, eliminating the need for large bolts and allowing for a simple, symmetrical weld zone around the axis, enabling precise fitting and firm fixation without complex structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bolts are used for fastening the cover to the carrier, then the fixation is firm and reliable, but the bolts must be of large type and have sufficient strength to bear torque, increasing device complexity and manufacturing cost
Solution Approach 1:
The patent replaces the mechanical fastening system (bolts) with a welding system. The cover is welded to the carrier using arc welding or other welding methods, eliminating the need for large torque-bearing bolts. This substitution maintains fixation reliability while simplifying the fastening structure and reducing the number of components.
2Device complexity
If welding is used to fix the cover to the carrier, then the device structure is simplified, but complex structures are required on the case and cover to adapt for welding, increasing manufacturing complexity and cost
Solution Approach 1:
The patent incorporates welding preparation features (such as welding beads or protrusions) directly into the molding process of the carrier and cover. This preliminary action during molding eliminates the need for separate welding structure additions, simplifying manufacturing while enabling welding fixation. The welding features are integrated into the base design rather than added as complex separate structures.
3Strength
If large bolts are used to bear torque from the ring gear, then sufficient strength is achieved, but the bolt size and type increase, raising working cost
Solution Approach 1:
The patent replaces the mechanical bolt fastening system with a welding connection system. The welding joint directly transfers torque from the ring gear to the carrier without requiring large torque-bearing bolts. This substitution maintains sufficient strength for torque transmission while reducing component size and manufacturing cost.
4Ease of operation
If the case is divided into two pieces for convenience of carrying mechanisms, then assembly convenience is improved, but additional fastening structures are required, increasing device complexity
Solution Approach 1:
The patent replaces mechanical fastening (bolts) with welding to join the cover to the carrier. This substitution is particularly beneficial for two-piece cases, as welding provides a simple, direct connection method that does not require complex fastening structures. The welding approach maintains assembly convenience while reducing the complexity of joining mechanisms.
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
This design reduces the risk of bolt failure due to torque transmission, minimizes the need for precise alignment, and lowers production costs by allowing the use of optimal materials for each component, while maintaining a rotationally symmetrical weld zone to prevent thermal deformation issues.
Implementation Method 1
a weld metal joining the carrier, the cover and the ring gear together
Data Source
AI summary
A case for a differential gear set includes: a rotatable carrier having a cylindrical fitting face and a radially projecting flange having an axially directed butting face; a cover having a brim section so projecting axially as to fit on an outer periphery of the flange and so dimensioned as to align an end face of the brim section with the butting face; a ring gear fitting on the fitting face and having a back face in contact with the butting face; and a weld metal uniting the carrier, the cover and the ring gear together, wherein the butting face of the carrier, the end face of the cover and the back face of the ring gear are so dimensioned as to keep a circular groove exposed outward and reaching an interface between the back face and the butting face and the weld metal fills the groove.