Starter Ring Gear Axial Elastic Shock Absorption
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Solution Overview
Problem
Existing starters for internal combustion engines face issues with shock absorption, leading to wear and breakage of the toothed crown wheel due to inadequate material properties and positioning, which results in non-homogeneous stresses on the teeth and displacement of the ring gear.
Innovation Solution
The solution involves a toothed ring gear connected to the starter casing via an elastic connection, where the toothed ring is made of steel and the elastic element is made of plastic, allowing for shock absorption and resistance to torque shocks, with a connecting element that positions the elastic element axially and maintains rotational connection, enabling standardized use across different starter sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the crown wheel is made of plastic material with elastomer pads, then the structure can be simplified, but the crown wheel suffers from wear and breakage due to inadequate shock absorption
Solution Approach 1:
The crown wheel assembly is segmented into distinct functional components: a steel crown wheel for structural integrity and tooth engagement, and separate elastomer damping pads for shock absorption. This segmentation allows each component to be optimized for its specific function, preventing the wear and breakage that occurs when a single material must perform both structural and damping functions.
Solution Approach 2:
The solution employs composite construction by combining steel crown wheel with elastomer damping pads. The steel provides the necessary strength and wear resistance for the toothing, while the elastomer material provides shock absorption capabilities. This composite approach resolves the contradiction by allowing each material to contribute its superior properties to the overall assembly.
2Manufacturing precision
If the crown wheel is rigidly fixed in the starter housing, then positioning is precise, but shocks cause wear and breakage of the toothing
Solution Approach 1:
Elastomer damping pads are installed between the crown wheel and the starter housing before operation begins. These pads are positioned to absorb shocks and vibrations that occur during normal operation, particularly during engine starting. The cushioning effect protects the toothing from wear and breakage while allowing the crown wheel to maintain its precise position through the damping action of the pads.
3Ease of operation
If axial play is maintained in the crown wheel, then displacement is allowed, but this causes non-homogeneous stresses on the teeth
Solution Approach 1:
The elastomer damping pads are designed with specific dimensional parameters and material properties that allow them to absorb axial play while maintaining homogeneous stress distribution. The pads are positioned and dimensioned to distribute loads evenly across the crown wheel teeth, converting the potentially harmful axial displacement into controlled elastic deformation of the damping material, thereby maintaining uniform stress distribution during operation.
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 configuration effectively absorbs torque shocks, preventing breakage of the toothed crown and maintaining the structural integrity of the starter, while minimizing radial volume and ensuring homogeneous stress distribution on the teeth.
Implementation Method 1
The elastic element able to absorb a torque shock transmitted to the crown
Data Source
Figure 1
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AI summary
The invention relates to an electric starter for an internal combustion engine comprising a housing, an electric motor comprising an inner shaft that is rotatably mobile in relation to the housing about a longitudinal axis, an output shaft driven by the inner shaft, and a reducer assembly rotatably connecting the inner shaft and the output shaft, said reducer assembly comprising a ring gear (46) fixed to the housing by means of an elastic connection. The elastic connection between the ring gear (46) and the housing comprises an elastic element (90) that is axially at a distance from the ring gear (46), and a rotatably connecting element (80) mounted axially between the ring gear (46) and the elastic element (90), the ring gear (46) being carried by the housing by means of the connection element (80), said elastic element (90) being able to absorb a coupling impact transmitted to the ring gear (46).