Disc Brake Screw-Nut Layout for Even Brake Pad Thrust
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Solution Overview
Problem
Existing disc brakes have a complex and bulky structure due to the interface between the motor shaft and the nut, and the axial thrust on the brake pad is not well distributed, leading to potential tightening faults, especially with larger brake pads.
Innovation Solution
A disc brake design featuring a screw/nut system where the screw is fixed in translation and driven by a motor pinion, with a nut fixed in rotation and driven in translation, allowing for better distribution of axial thrust through two pistons, and a simplified structure with fewer parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the nut is driven by the motor shaft directly, then the structure is simpler, but the axial thrust is not well distributed on the brake pad
Solution Approach 1:
The patent divides the single actuation force into multiple forces by introducing two pistons that apply thrust at different locations on the brake pad. This segmentation of the thrust application points distributes the axial load more evenly across the brake pad surface, preventing localized stress concentrations that could cause tightening faults.
Solution Approach 2:
The patent introduces an intermediary mechanism (the two-piston system) between the motor shaft and the brake pad. This intermediary distributes the motor's rotational force through the screw-nut mechanism to multiple pistons, which then apply the thrust force at optimally distributed locations on the brake pad, improving force distribution without requiring direct motor-to-pad connection.
2Volume of moving object
If the interface between motor shaft and nut is reduced, then the footprint is smaller, but the structure becomes more complex
Solution Approach 1:
The patent inverts the traditional arrangement by having the screw rotate while the nut translates linearly, rather than the conventional approach where the nut rotates and the screw translates. This inversion allows the motor shaft to connect directly to the rotating screw, eliminating the need for a complex rotational interface at the nut and reducing the overall footprint while maintaining actuation functionality.
Solution Approach 2:
The screw-nut mechanism serves multiple functions simultaneously: it converts rotational motion to linear motion, provides mechanical advantage for force multiplication, and enables compact packaging by eliminating separate rotational interfaces. This multi-functionality reduces the overall system footprint while maintaining actuation capability.
3Device complexity
If the axial thrust is applied punctually at the end of the rod, then the structure is simpler, but the thrust force is not distributed over the entire brake pad
Solution Approach 1:
The patent segments the single punctual thrust application into multiple distributed thrust applications by using two separate pistons. Each piston applies force at a different location on the brake pad, creating a distributed force pattern that covers a larger area of the brake pad surface, improving contact uniformity and preventing localized stress concentrations.
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 design results in a more compact, cost-effective disc brake with improved distribution of axial thrust, reducing the risk of tightening faults and allowing for greater flexibility with larger brake pads.
Implementation Method 1
a screw/nut system where the screw is fixed in translation and driven by a motor pinion, with a nut fixed in rotation and driven in translation
Implementation Method 2
These pads are clamped against the disc by the action of one or more brake pistons... This clamping thus creates friction between the brake pads and the disc, which dissipates the kinetic energy of the wheel in the form of heat and achieves braking
Data Source
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AI summary
The invention relates to a disc brake (F) comprising a caliper (E) comprising, opposite each other, a fixed brake pad (P1) and a movable brake pad (P2), as well as a mechanism for actuating the movable brake pad (P2) comprising a screw/nut system and means for transmitting a rotational movement of a motor shaft (4) to the screw/nut system to actuate the movable brake pad (P2), said actuating mechanism being housed in a housing (L) in the caliper (E). The invention consists in that the screw (1) is mounted fixed in translation in said housing (L) and can be driven in rotation by the transmission means, the nut (2) mounted fixed in rotation in said housing (L) being able to be driven in translation along the screw (1) during rotation of the latter, said nut (2) carrying two pistons (9) bearing against the movable brake pad (P2).