Automotive Actuator Evoloid Gearing for Compact High-Ratio Drive
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Solution Overview
Problem
Existing actuators for automotive applications require a compact design to fit cramped installation conditions while achieving high transmission ratios, often relying on multi-stage gear systems that are heavy and noisy.
Innovation Solution
Implementing a single-stage evoloid gearing system where the electric motor's drive shaft directly meshes with an evoloid pinion, which acts on the actuating element, and optionally includes additional gear stages with spur or helical gears, allowing for reduced size and weight, improved efficiency, and lower noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional actuator design with separate housing and actuator unit is used, then assembly and disassembly require multiple steps and tools, but this increases manufacturing complexity and time consumption
Solution Approach 1:
The housing and actuator unit are merged into a single integrated component where the actuator unit is directly formed as part of the housing structure. This eliminates the need for separate assembly steps and fastening elements, allowing the entire actuator to be produced as one piece while maintaining functional separation between the housing and actuator components.
2Ease of operation
If the actuator rod is held in a recess with clearance, then the rod can move freely, but this creates play and reduces positioning precision
Solution Approach 1:
The connection between the actuator rod and housing transitions from a static clearance fit to a dynamic interference fit. During assembly, the rod is inserted with sufficient force to deform the elastic material of the housing recess, creating an interference connection that eliminates play. The elastic material allows for controlled deformation and recovery, maintaining both mobility and precision.
Solution Approach 2:
The physical state of the housing recess material changes from rigid to elastic during the assembly process. By heating or mechanically softening the elastic material temporarily, the rod can be inserted easily, and upon cooling or recovery, the material returns to its original state creating a tight interference fit that eliminates clearance while maintaining rod functionality.
3Manufacturing precision
If the actuator rod is pressed tightly against the housing bottom, then positioning is accurate, but this creates stress concentration and potential damage
Solution Approach 1:
The housing recess is designed with varying local properties: the bottom surface has higher stiffness to provide accurate positioning, while the walls transitioning to the opening have increased elasticity to absorb assembly stresses. This gradient in material properties or structural thickness allows the rod to be securely positioned without concentrating damaging stresses at any single location.
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 design achieves a more compact and lightweight actuator with higher efficiency and reduced noise, enabling high transmission ratios and manual reset capability, suitable for applications like locking mechanisms in electric vehicles.
Implementation Method 1
The actuator rod (33) is pressed into the housing (31) until the bottom (32) of the recess (38) engages the actuator rod (33). The recess (38) is formed in an elastic material such that the recess (38) yields elastically to compressive force applied to the actuator rod (33).
Data Source
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AI summary
The invention relates to applications, in particular for motor vehicle closing devices. The basic design of the motor vehicle has an electric motor (1) and an actuating element (5) which is acted upon by the electric motor (1) directly or indirectly via a powertrain (2, 3, 4). The powertrain (2, 3, 4) is provided with at least one Evoloid toothing (2, 3). According to the invention, a drive shaft (1') of the electric motor (1) is equipped with an Evoloid pinion (2) which meshes with an Evoloid output gear (3) at the input of the powertrain (2, 3, 4), thereby directly producing the Evoloid toothing (2, 3).