Compact EPB Actuator with Cycloidal Reducer
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Solution Overview
Problem
Existing electric parking brake actuators are complex, bulky, and unreliable, with high manufacturing costs and noise issues, and they often lack mechanical efficiency and consistency in locking forces under varying conditions.
Innovation Solution
A compact actuator for electric parking brakes featuring a cycloidal reduction assembly with a minimal number of parts, low manufacturing costs, and a simple structure, utilizing a toothed belt and pulley system with a cycloidal motion to achieve high transmission ratios and precise operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional gear assemblies (belt gears, worm gears, cylindrical gears, planetary gears) are used in parking brake actuators, then the actuator can achieve braking function, but the device becomes complex, bulky, and costly with assembly difficulties and noise issues
Solution Approach 1:
The patent combines the motor, reduction gear, and brake mechanism into a single integrated actuator assembly. The motor shaft directly connects to the reduction gear, which is integrated with the brake mechanism, eliminating the need for separate cable assemblies and multiple connection points. This merging reduces overall device complexity while maintaining operational reliability.
Solution Approach 2:
The actuator is divided into distinct functional modules: motor unit, reduction gear unit, and brake mechanism unit. Each module can be independently manufactured and assembled, simplifying the overall construction process and reducing assembly complexity while ensuring reliable operation of each component.
2Reliability
If traditional gear assemblies with multiple components are used, then braking function is achieved, but manufacturing costs increase and assembly precision requirements become higher
Solution Approach 1:
The reduction gear and brake mechanism are merged into a single integrated unit, reducing the total number of parts that need to be manufactured and assembled. This integration simplifies manufacturing processes and reduces quality control requirements while maintaining reliable braking function.
Solution Approach 2:
The reduction gear serves dual functions: it reduces motor speed and simultaneously provides the mechanical advantage needed for brake operation. This multi-functionality eliminates the need for separate braking mechanisms, simplifying manufacturing while ensuring reliable brake function.
3Force
If traditional actuator designs with many components are used, then braking capability is achieved, but the actuator becomes bulky and difficult to install in vehicle spaces
Solution Approach 1:
The brake mechanism is nested within the reduction gear housing, and the entire assembly is integrated with the motor unit. This nested arrangement allows the actuator to generate high locking forces while occupying minimal space, making it suitable for installation in constrained vehicle environments.
Solution Approach 2:
By merging the motor, reduction gear, and brake mechanism into a single compact assembly, the actuator achieves high locking force capability without requiring additional space for separate components, thus reducing overall actuator volume while maintaining force output.
4Reliability
If traditional gear assemblies are used, then braking function is achieved, but noise is generated and mechanical efficiency is reduced due to clearance and friction
Solution Approach 1:
The patent replaces traditional meshing gear systems with a direct-drive reduction mechanism that eliminates tooth meshing noise and vibration. The motor shaft directly connects to the reduction gear through a controlled mechanical linkage, reducing noise and vibration while maintaining reliable braking operation.
Solution Approach 2:
The actuator incorporates dynamic elements that allow for controlled movement and absorption of mechanical shocks and vibrations during operation. This dynamic design reduces noise and vibration transmission while ensuring consistent braking performance under varying operating conditions.
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 compact actuator provides reliable, efficient, and consistent operation with reduced elastic deformations and collateral loads, achieving high transmission ratios in a compact and economical design.
Implementation Method 1
a toothed belt (15) to a toothed pulley (16) arranged on a shaft (17) in input to the actuator (12)
Implementation Method 2
A compact actuator for electric parking brakes featuring a cycloidal reduction assembly with a minimal number of parts
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
An actuator for an electric parking brake, wherein the actuator comprises an electric motor (11) and a cycloidal reducer assembly (12) connected downstream of the electric motor (11), wherein said cycloidal reducer assembly (12) comprises an upper cover (19) and a lower cover (20) containing a cycloidal assembly, which are crossed by a shaft (17) carrying an eccentric formation (18) in an intermediate area thereof at said interposed central crown (26), characterised in that a central crown (26) is provided interposed between said upper cover (19) and lower cover (20) which are thus arranged in a pack, wherein said interposed central crown (26) is provided with inner teeth (30) facing a gear pair (31) having a diameter smaller than the internal diameter of the teeth (30), wherein, moreover, said gear pair (31) has a thickness not greater than that of the central crown (26) and is arranged therein, wherein said gear pair (31) with interposition of a bearing (32) is arranged on said eccentric formation (18) of the shaft (17) and is therefore driven to rotate the shaft (17) itself with cycloidal motion, wherein said gear pair (31) provides on its body through holes (33) within which pins (34) are arranged which extend from one side of a disc formation (28), which in turn extends from the other side downwards towards the lower cover (20) in a shaft extension (29). wherein said disc formation (28) and said shaft extension (29) make a real output shaft of the actuator.