Integral Ring Gear Housing for Compact Planetary Motor-Reducer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional geared motors for motor vehicle disc or drum brake actuators lack compactness, robustness, and energy efficiency, and are not adequately protected against environmental dust and dirt, particularly in drum brake motorization.
Innovation Solution
A geared motor design featuring an electric motor, epicyclic gear train with a ring gear integral to the housing, and a planetary gear reduction system that provides a high gear ratio for low displacement with sufficient effort, while being housed in a casing for protection and ease of manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional pinion gears with external contacts are used in cascade, then the geared motor can be assembled with standard components, but the device occupies excessive space and lacks compactness
Solution Approach 1:
The patent merges the ring gear with the housing into a single integral component, eliminating the need for a separate ring gear part. This consolidation reduces the number of components and occupies less space while maintaining the planetary gear train's functional integrity.
Solution Approach 2:
The patent employs a planetary gear train with planet gears that rotate on journals and can translate axially between the collar and driven planet carrier. This dynamic configuration allows compact packaging of multiple moving components within the housing volume.
2Power
If high gear ratio is achieved through multiple pinion stages, then sufficient torque is obtained, but energy losses increase and efficiency decreases
Solution Approach 1:
The planetary gear train provides high gear ratio in a single stage through the arrangement of sun gear, planet gears, and ring gear, eliminating the need for multiple pinion stages. This reduces the number of meshing interfaces and associated energy losses while achieving the required torque multiplication.
Solution Approach 2:
The planet gears are pre-positioned on journals that allow controlled axial translation, enabling the gear train to engage and disengage smoothly. This preliminary positioning reduces impact losses and ensures continuous contact during operation.
3Reliability
If the geared motor mechanism is exposed to the environment, then the structure remains simple and accessible, but dust and dirt contaminate the mechanism reducing reliability
Solution Approach 1:
The ring gear is formed as an integral part of the housing, creating a sealed enclosure that protects the planetary gear train from environmental contamination. The housing structure itself becomes a functional component rather than just a protective shell.
Solution Approach 2:
The housing acts as a protective shell that encloses and seals the gear mechanism, preventing dust and dirt from entering while maintaining structural integrity and providing mounting surfaces for other components.
4Volume of moving object
If separate ring gear component is used, then assembly and manufacturing are simplified, but the overall device volume increases and compactness is reduced
Solution Approach 1:
The ring gear is formed integrally with the housing through casting or molding processes, eliminating the need for separate ring gear manufacturing and assembly operations. This consolidation reduces part count and assembly steps while maintaining the required gear geometry and tolerance.
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 solution offers improved energy efficiency, adaptability to various braking functions, and reduced production and maintenance costs, ensuring compatibility with modern vehicle control systems and allowing multiple motorization performance levels with the same actuator model.
Implementation Method 1
the reducer has an epicyclic gear train and comprises at least one ring gear internally toothed which is integral with the housing
Data Source
AI summary
The invention relates to a motor-reducer, in particular for powering an actuator of a disc or drum brake of a motor vehicle, for example in the context of a "dual-mode" drum brake. The invention also relates to a drum brake and to a braking device provided with same. The motor-reducer includes an electric motor, a reduction gear and a rotary output coupled with the electric motor via the reduction gear. Typically, the motor-reducer also includes a housing which contains the motor. The reduction gear has a planetary gearset and includes at least one internal gear ring which is secured to the housing and integrally formed with the housing.