Ball Ramp Assembly with Variable Pitch Grooves for Axial Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing axial setting devices for actuating multi-plate couplings in motor vehicle drivelines lack rapid reaction time and accurate control, particularly in differential assemblies requiring variable torque distribution for driving stability.
Innovation Solution
A ball ramp assembly with two discs, where each disc has circumferentially distributed ball grooves with varying depths, featuring a first groove portion with a steeper pitch and a second groove portion with a flatter pitch, allowing for quick axial displacement and precise control of the friction coupling, enabling rapid actuation and sensitive adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If non-linear control curves with initially steeper and then progressively flattening profile are used in ball grooves, then accurate coupling control in the second actuation phase is improved, but the reaction time in the first actuation phase is increased
Solution Approach 1:
The ball groove is segmented into two distinct portions: a first groove portion with a steeper pitch for rapid initial actuation, and a second groove portion with a progressively flattening profile for accurate control. This segmentation allows each portion to optimize for its specific function, resolving the contradiction between fast reaction and accurate control.
Solution Approach 2:
The groove profile transitions from a steeper pitch in the first portion to a progressively flattening profile in the second portion, creating a dynamic control characteristic that adapts to different actuation phases. This dynamic profile enables rapid initial movement followed by precise positioning.
2Loss of time
If a steeper groove pitch is used in the first groove portion, then the reaction time is reduced, but the control precision in the operating range is decreased
Solution Approach 1:
Different portions of the ball groove are assigned different pitch characteristics: the first groove portion has a steeper pitch optimized for rapid reaction, while the second groove portion has a progressively flattening profile optimized for precise control. This local differentiation of groove quality resolves the contradiction between speed and precision.
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 solution provides a short reaction time and accurate control of the friction coupling, ensuring efficient torque distribution and driving stability in motor vehicles by covering a greater axial setting path initially and allowing sensitive adjustment in the operating range.
Implementation Method 1
The ball ramp assembly comprises an axially supported disc and a disc which is axially displaceable relative thereto. Each two ball grooves positioned opposite one another form a pair and in each pair of ball grooves, a ball is held by which the discs axially support one another.
Implementation Method 2
a friction coupling for achieving a variable torque distribution between two driving axles of a differential drive
Data Source
AI summary
An axial setting device includes two discs which are centered on a common axis. One is axially supported and the other one is axially displaceable, and at least one is rotatingly drivable. The two discs on their end faces, each have a plurality of circumferential ball grooves. The ball grooves each comprise a depth which decreases in the same direction, and each pair of opposed ball grooves accommodates a ball. At least the ball grooves of one of the two discs, starting from the region of the greatest groove depth, comprise a first groove portion with a greater pitch and an adjoining second groove portion with a smaller pitch, wherein the first groove portion extends over a smaller circular-arch-shaped portion than the second groove portion.