Brake Caliper Ball Screw Assembly for Low-Wear Motion Conversion
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Solution Overview
Problem
Existing brake systems face inefficiencies in converting rotary motion to linear motion, leading to high friction and wear, particularly during braking operations, due to the use of lead screws which result in sliding friction, and lack a reliable mechanism for applying and releasing braking forces effectively.
Innovation Solution
The implementation of a piston assembly with a ball screw assembly or ball ramp assembly that converts rotary motion into linear motion using rolling friction, reducing wear and increasing efficiency by utilizing a spindle that forms a lead screw with an interior surface, allowing for pre-load torque and angular articulation to manage uneven loads and facilitate smooth braking operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lead screw is used to convert rotary motion to linear motion in a brake piston, then the braking force can be applied, but sliding friction occurs leading to high wear and inefficiency
Solution Approach 1:
The patent replaces the traditional lead screw mechanism with a ball screw assembly that uses rolling friction instead of sliding friction. The ball screw assembly includes a ball nut and ball screw with recirculating balls that convert rotary motion to linear motion with significantly reduced friction and wear, while maintaining the ability to apply braking force effectively
Solution Approach 2:
The patent changes the friction parameter by introducing pre-load torque to the ball screw assembly. The pre-load torque eliminates backlash and ensures consistent contact between the ball nut and ball screw, optimizing the transition from rotary to linear motion while maintaining reliable braking force application
2Productivity
If a ball screw assembly is used to reduce friction, then wear is reduced and efficiency increases, but device complexity increases
Solution Approach 1:
The patent integrates the ball screw assembly within the existing piston cavity, nesting the ball nut and ball screw components inside the piston structure. This nested arrangement reduces the overall space required and minimizes the increase in device complexity while maintaining the efficiency benefits of rolling friction
Solution Approach 2:
The ball screw assembly serves multiple functions: it converts rotary motion to linear motion, reduces friction and wear through rolling contact, and provides pre-load torque to eliminate backlash. This multi-functionality justifies the increased complexity by delivering multiple performance improvements simultaneously
3Reliability
If pre-load torque is applied to manage uneven loads, then braking performance improves, but the force required to actuate the brake increases
Solution Approach 1:
The patent introduces a spring as an intermediary element that stores and releases energy to compensate for uneven loads during braking operation. The spring maintains consistent contact and force distribution in the ball screw assembly, improving braking performance consistency without requiring excessive actuation force
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 solution significantly reduces friction and wear by transitioning from sliding to rolling friction, enabling a more efficient and reliable application and release of braking forces, allowing for lighter components and smaller motors to be used while maintaining effective braking performance.
Implementation Method 1
The ball screw assembly and the lead screw are configured for the lead screw to move linearly followed by the ball screw assembly moving linearly to move the piston upon application of the brake
Data Source
AI summary
Disk brake systems including disk brake systems that are motor actuated are discussed. As a part of these brake systems, various piston assemblies are also discussed, including piston assemblies that include a piston; a spindle; a ball screw assembly within the piston, wherein the spindle forms a lead screw with an interior surface of the ball screw assembly and the ball screw assembly and the lead screw are configured for the lead screw to move linearly followed by the ball screw assembly moving linearly to move the piston upon application of the brake. Additional embodiments of piston assemblies that include ball ramp actuators are also discussed.