Differential Gear Assembly With Spherical Locking for Easy Assembly

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Solution Overview

Problem

Existing differential gear assemblies face a conflict between mechanical stability, ease of manufacture, and assembly, making them difficult to produce and assemble while maintaining lightweight and compact design.

Innovation Solution

A differential gear assembly comprising a ring-shaped gear with spherical contact surfaces and reception slots, a bevel gear unit supported on a cross shaft, and a bevel gear carrier with spherical contact surfaces, allowing for positive locking and easy assembly/disassembly without tools, while maintaining mechanical stability and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the differential gear assembly is designed as a single integrated component, then mechanical stability and strength are improved, but manufacturing complexity and assembly difficulty increase

Engineering Contradiction:
Improvemechanical stabilityVSAvoidassembly difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The differential gear assembly is divided into separate components: a ring-shaped gear, a bevel gear carrier, and a cross shaft. These segments can be manufactured independently using standard machining processes, then assembled together through the reception slots and positive locking mechanism, reducing overall manufacturing complexity while maintaining structural integrity

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the differential gear assembly uses multiple separate components, then ease of manufacture and assembly are improved, but mechanical stability and strength may deteriorate

Engineering Contradiction:
Improvemanufacturing easeVSAvoidmechanical stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The spherical contact surfaces on both the ring-shaped gear and bevel gear carrier create a curved, self-centering connection interface. This spherical geometry distributes loads more evenly across the contact area and provides inherent alignment, enhancing the mechanical stability of the assembled components while allowing them to remain separate manufacturable parts

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Weight of moving object

If the differential gear assembly is designed to be lightweight and compact, then vehicle fuel efficiency is improved, but mechanical strength and torque capacity may deteriorate

Engineering Contradiction:
Improveassembly weightVSAvoidtorque capacity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

By segmenting the assembly into separate components connected through reception slots, each part can be optimized for minimal weight while maintaining its structural function. The cross shaft can be slender, the bevel gear carrier can be thin-walled, and the ring-shaped gear can be lightweight, yet the assembly collectively withstands high torques through the distributed spherical contact surfaces

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4382772B1Differential gear assembly, drivetrain for a vehicle, method for assembling a differential gear assembly and method for disassembling a differential gear assembly
Publication Date: 2026.02.11 VOLVO CAR CORP
  • EP4382772B1 patent drawingFigure 1~2
  • EP4382772B1 patent drawingFigure 3~4
  • EP4382772B1 patent drawingFigure 5~7

AI summary

The disclosure relates to a differential gear assembly (20) comprising a ring-shaped gear (26) being rotatable around an axis (A) and a bevel gear unit (44) with four bevel gears (48a, 48b, 48c, 48d) being supported on a bevel gear carrier (46). Two bevel gears (48a, 48b, 48c, 48d) are additionally supported on a cross shaft (60). The ring-shaped gear (26) comprises at least two primary contact surfaces (38a, 38b) having a spherical shape and the bevel gear carrier (46) comprises at least two secondary contact surfaces (56a, 56b) having a spherical shape. Each of the secondary contact surfaces (56a, 56b) contacts an associated primary contact surface (38a, 38b). Moreover, two reception slots (40a, 40b) are arranged on the ring-shaped gear (26) and an end (62a, 62b) of the cross shaft (60) is received in each of the two reception slots (40a, 40b) such that the ends (62a, 62b) and the reception slots (40a, 40b) form a positive locking being effective in a circumferential direction of the ring-shaped gear (26). Additionally, a drivetrain for a vehicle comprising such a differential gear assembly (20), a method for assembling a differential gear assembly (20), and a method for disassembling a differential gear assembly (20) are explained.