Speed Reducer Stopper Structure for Crankshaft Hermetic Sealing
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Solution Overview
Problem
Conventional speed reducers with screw-type caps suffer from inadequate sealing, allowing lubricant intrusion due to gaps between male and female threads, which affects their hermeticity.
Innovation Solution
A speed reducer design featuring a carrier with a recess and a stopper mechanism that prevents crankshaft movement, utilizing a non-rotatable stopper with a smaller diameter than the crankshaft bearing to enhance sealing, and incorporating a sealing member in the through hole to maintain hermeticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw-type cap is used to prevent axial movement of the crankshaft, then the crankshaft is constrained effectively, but gaps between male and female threads cause insufficient sealing and lubricant intrusion
Solution Approach 1:
The invention extracts the sealing function from the threaded cap structure and implements it through a dedicated stopper component with sealing features. The stopper is pressed against the crankshaft end surface by elastic deformation of the carrier wall, creating a separate sealing mechanism that does not rely on thread gaps.
Solution Approach 2:
The carrier wall acts as an intermediary element that transmits elastic deformation force to press the stopper against the crankshaft. This intermediary mechanism enables sealing without requiring direct threaded contact between the cap and carrier, eliminating the sealing problem associated with thread gaps.
2Reliability
If a stopper with smaller diameter than the crankshaft bearing is used, then sealing performance is enhanced, but the stopper may not provide sufficient axial constraint force
Solution Approach 1:
The carrier wall is designed to elastically deform under operational loads, dynamically adjusting the pressing force applied to the stopper. This elastic deformation mechanism ensures that the stopper maintains adequate axial constraint force on the crankshaft while preserving the sealing interface, resolving the contradiction between sealing and constraint 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
The design achieves improved hermeticity by preventing lubricant intrusion and ensuring accurate attachment of the crankshaft bearing, enhancing the overall sealing performance of the speed reducer.
Implementation Method 1
a stopper disposed on the bottom surface of the recess and preventing the crankshaft from moving in a direction toward the bottom surface along a rotation axis of the crankshaft, the stopper having a first end surface and a second end surface opposing the first end surface in an axis direction extending along the rotation axis of the crankshaft
Implementation Method 2
incorporating a sealing member in the through hole to maintain hermeticity
Data Source
Figure 1
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AI summary
A speed reducer (1) according to one embodiment of the invention includes a carrier (24) having a recess (50) therein, a crankshaft (12) disposed in the recess (50), and a stopper (60) that is disposed on a bottom surface (51) of the recess and prevents the crankshaft (12) from moving in a direction along a rotation shaft (A2) of the crankshaft (12) toward the bottom surface (50).