Electronic Brake Ball Screw Guide for Stable Piston Coupling
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Solution Overview
Problem
Existing electronic brake devices for vehicles face challenges in converting rotary motion from an electric motor into linear motion of a piston effectively, leading to uncoupling issues between the nut and piston due to directional changes in rotational force, which affects the stability and efficiency of braking hydraulic pressure generation.
Innovation Solution
The electronic brake device incorporates a cylinder unit with a screw shaft, a nut unit with a flange part, a piston unit, and a guide member that restricts the rotation of the flange part, allowing the nut unit to move linearly while preventing uncoupling, and a washer unit with inclined threads to enhance coupling stability, thereby converting rotary motion into linear motion and maintaining hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ball screw unit is used to convert rotary motion to linear motion, then the conversion function is achieved, but uncoupling occurs between the nut and piston when directional changes happen
Solution Approach 1:
The device is divided into distinct functional modules: the ball screw unit for motion conversion, the guide member for motion constraint, and the coupling mechanism for connection. This segmentation allows each component to perform its specific function effectively while maintaining overall system reliability during directional changes.
Solution Approach 2:
A guide member is introduced as an intermediary component between the nut and piston. This guide member constrains the nut to linear motion only, preventing rotational movement that would cause uncoupling during directional changes, thereby maintaining coupling stability without significantly increasing overall device complexity.
2Adaptability or versatility
If the nut is allowed to rotate freely during reciprocating motion, then the ball screw unit can respond to directional changes, but coupling between the nut and piston is released
Solution Approach 1:
The guide member provides dynamic constraint that allows the nut to move linearly in response to directional changes while preventing rotational movement. This dynamic constraint maintains coupling stability during reciprocating motion without sacrificing the ability to respond to directional changes in the screw shaft rotation.
3Manufacturing precision
If a guide member is added to restrict nut rotation, then linear motion guidance is improved, but device complexity increases
Solution Approach 1:
The guide member serves multiple functions simultaneously: it guides the linear motion of the nut, restricts rotational movement, and maintains proper alignment between the nut and piston. This multi-functionality achieves precise motion guidance without proportionally increasing device complexity.
Solution Approach 2:
The guide member is integrated with the existing ball screw unit and piston assembly, combining multiple functions into a single component structure. This merging approach provides precise motion guidance while minimizing the increase in overall device complexity.
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 configuration improves noise, vibration, and harshness (NVH) performance, increases rigidity, reduces assembly complexity, and prevents uncoupling between the nut and piston, ensuring effective conversion of rotary motion to linear motion for stable braking hydraulic pressure generation.
Implementation Method 1
a ball screw unit is applied to the electric brake device, which includes a screw shaft that is axially coupled to the electric motor and is axis-rotated by a rotational force received from the electric motor and a nut that is coupled to the screw shaft with a ball interposed therebetween and moves in an axial direction of the screw shaft
Data Source
AI summary
Proposed is an electronic brake device of a vehicle including: a cylinder unit; a screw shaft provided in the cylinder unit, and axis-rotated by a rotational force received from a motor; a nut unit coupled to the screw shaft with a ball member interposed therebetween, reciprocates in an axial direction of the screw shaft according to a rotating direction of the screw shaft, and provided with a flange part on one side end portion thereof; a piston unit coupled to the nut unit, and moves in conjunction with the nut unit; a sleeve unit provided inside the cylinder unit, and guides the piston unit to be inserted and move therethrough; and a guide member provided inside the cylinder unit, restricts rotation of the flange part so that rotation of the nut unit is restricted, and guides movement of the flange part.