Telescoping Ball Nut Assembly for Compact Brake Packaging
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Solution Overview
Problem
There is a need in the automotive industry to reduce the packaging size and weight of brake systems, particularly in electric park brake and electromechanical brake systems, to accommodate other vehicle components and enhance overall vehicle efficiency.
Innovation Solution
A telescoping ball nut assembly is introduced, comprising an inner nut, an outer nut, and a screw with specific stop mechanisms and tracks that allow for multi-stage axial translation, reducing the overall length while maintaining functionality, and is configured to fit within small packaging spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional ball nut assembly is used, then the braking functionality is maintained, but the packaging space and weight are excessive
Solution Approach 1:
The patent implements a telescoping ball nut assembly where an inner ball nut is nested within an outer ball nut. The inner nut contains its own ball track and apply mechanism, while the outer nut provides additional travel capacity. This nested configuration allows the assembly to achieve the required braking stroke in a compact form factor, reducing packaging space while maintaining full braking functionality through the combined action of both nuts.
Solution Approach 2:
The ball nut assembly is segmented into multiple independent components: an inner ball nut with its own ball track and apply stop, an outer ball nut with separate ball track, and a common screw. Each segment can translate axially independently during the multi-stage apply operation, allowing the system to achieve total braking stroke through cumulative translation of segments rather than requiring a single long-travel component.
2Length of moving object
If the ball nut assembly length is reduced, then packaging space is freed, but the braking stroke capability may be compromised
Solution Approach 1:
The patent employs a dynamic, multi-stage apply mechanism where the transition from first stage to second stage is triggered by the interaction between the inner nut's apply stop and the screw's apply stop. During the first stage, the inner nut translates axially to initiate braking. When its apply stop engages the screw's apply stop, it triggers a transition where the outer nut begins its axial translation, cumulative with the inner nut's movement. This dynamic staging allows the compact assembly to achieve the required total braking stroke and force without increasing overall length.
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 telescoping ball nut assembly achieves a reduced overall length compared to conventional designs, enabling efficient packaging and maintaining the braking functionality, thus addressing the need for compactness and weight reduction in brake systems.
Implementation Method 1
The screw, the inner nut, and the outer nut each may comprise tracks and the telescoping ball nut assembly may comprise balls disposed within the tracks
Implementation Method 2
The tracks may helically wind around the screw, the inner nut, and the outer nut, respectively
Data Source
AI summary
A telescoping ball nut assembly comprising an inner nut, an outer nut, and a screw. The inner nut has a release stop located on or proximate to a first end thereof and an apply stop located on or proximate to a second end thereof, the first end opposing the second end. The outer nut has a release stop located on or proximate to an end thereof corresponding in orientation to the first end of the inner nut. The screw comprises an apply stop located on or proximate to an end thereof corresponding in orientation to the second end of the inner nut. Pivotal translation of the screw causes axial translation of the inner nut and/or the outer nut.