Triple-shaft deflection gear for RWD vehicle floor height

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Solution Overview

Problem

Rear-wheel drive vehicles with front engines face challenges in lowering the vehicle floor while maintaining the existing angle of inclination of the motor-gear block, as conventional deflection gears require direct flanging to the transmission, leading to improper alignment of the cardan shaft.

Innovation Solution

A three-shaft deflection gear with conical gearing, where the input and output shafts are inclined relative to each other by 2 to 6°, allowing the cardan shaft to be lowered while maintaining the horizontal alignment of the motor-gear block, using conical gears that can be manufactured on conventional gear cutting machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If the deflection gear is flanged directly to the existing vehicle transmission, then the transmission output shaft is mounted at a lower level, but the cardan shaft experiences rotational irregularities and reduced service life due to improper alignment

Engineering Contradiction:
Improvevertical position of transmission output shaftVSAvoidservice life of cardan joints
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

A three-shaft deflection gear is introduced as an intermediary component between the transmission and the cardan shaft. This deflection gear includes an input shaft connected to the transmission output shaft, a center shaft, and an output shaft connected to the cardan shaft. The center shaft acts as a mediator to compensate for the angle of inclination, allowing the transmission output shaft to be mounted at a lower level while maintaining proper alignment of the cardan shaft, thereby eliminating rotational irregularities and extending service life.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Shape

If the cardan shaft is lowered to reduce vehicle floor height, then the vehicle floor can be lowered, but the angle of inclination of the motor-gear block must be changed

Engineering Contradiction:
Improveheight of vehicle floorVSAvoidangle of inclination of motor-gear block
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The power transmission path is segmented into three separate shafts (input shaft, center shaft, and output shaft) within the deflection gear. This segmentation allows each shaft to be independently angled to compensate for the lowered cardan shaft position. The center shaft is specifically angled relative to both the input and output shafts to maintain the original motor-gear block angle while accommodating the lowered floor height.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If conventional deflection gears are used with direct flanging, then the structure is simple, but the cardan shaft runs irregularly due to misalignment with the rear wheel axle

Engineering Contradiction:
Improvestructure of deflection gearVSAvoidsmooth running of cardan shaft
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The deflection gear is designed with specific local angular relationships between its shafts. The input shaft is angled at a first angle relative to the center shaft, and the output shaft is angled at a second angle relative to the center shaft. These locally optimized angular qualities ensure that the cardan shaft runs smoothly and is properly aligned with the rear wheel axle, while the overall structure remains relatively simple and can be integrated into existing transmissions.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2485911B1Redirecting transmission
Publication Date: 2013.09.18 OBERAIGNER WILHELM
  • EP2485911B1 patent drawingFigure 1~2

AI summary

The invention relates to a redirecting transmission for a rear-wheel-drive vehicle equipped with a front engine (1), which redirecting transmission (2) is intended for installation between a transmission (3) connected to the engine and a Cardan shaft (4). According to the invention, the redirecting transmission is designed as a triple-shaft transmission, wherein the input shaft (5) extends at an angle from the output shaft (6), which extends from the opposing or opposite side of the redirecting transmission relative to said input shaft (5), and the axes of said two shafts (5, 6) include an acute angle (A) of 2 to 6°, preferably 3 to 5°, in particular approximately 4°, located on the side of the output shaft (6).