Gearbox Mechanism Offset Divided Surfaces Absorb Positional Deviations
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Solution Overview
Problem
Conventional gearbox mechanisms experience positional deviations in the divided surfaces due to shaft projection deformations, leading to increased vibration and abnormal noise when the worm wheel rotates.
Innovation Solution
The gearbox mechanism is designed with offset divided surfaces and specific recess and projection shapes to absorb positional deviations, including semicircular and linear portions, and a stepped shaft projection and through-hole configuration to stabilize the worm wheel's rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tip of the shaft projection is staked to connect the divided bodies, then the divided bodies are connected, but the shaft projection deforms causing positional deviation in the divided surfaces
Solution Approach 1:
The shaft hole portion is designed with a semicircular cross-section and positioned offset from the axial center before assembly. This preliminary geometric configuration allows the shaft projection to be inserted and staked without causing positional deviation in the divided surfaces, as the semicircular shape accommodates the staking deformation while the offset position absorbs the resulting displacement.
2Ease of manufacture
If a through-hole and shaft projection are used to connect divided bodies, then assembly is simplified, but vibration and abnormal noise occur due to positional deviation
Solution Approach 1:
The shaft hole portion is pre-configured with a semicircular cross-section and an offset position relative to the axial center of the first gear. This preliminary geometric design anticipates the deformation that will occur during staking, allowing the shaft projection to be connected without causing positional deviation that would lead to vibration and abnormal noise during worm wheel rotation.
Solution Approach 2:
The invention converts the potentially harmful deformation of the shaft projection during staking into a beneficial feature. By positioning the shaft hole offset from the axial center and giving it a semicircular cross-section, the deformation is directed in a controlled manner that actually helps absorb positional deviations, thereby reducing vibration and abnormal noise instead of causing them.
3Strength
If the shaft projection is staked, then the divided bodies are firmly connected, but the shaft projection expands radially causing eccentricity
Solution Approach 1:
The shaft hole portion is designed with a semicircular cross-section and positioned offset from the axial center before the staking process. This preliminary configuration allows the shaft projection to expand radially during staking without causing eccentricity, as the semicircular shape and offset position provide a geometric framework that absorbs the expansion while maintaining proper alignment.
Data Source
AI summary
A gearbox includes a first divided body and a second divided body, and a shaft projection is formed on and a through-hole is formed in divided surfaces of the first divided body and the second divided body. A second recess on the second divided body side includes a second arc portion formed concentrically with an axis center of a worm wheel, and an upper linear portion and a lower linear portion which extend linearly toward the first divided body side from both ends of the second arc portion. A first recess on the first divided body side includes a first linear portion which extends linearly in a direction orthogonal to an intersecting direction, and an upper arc portion and a lower arc portion which are formed continuous to both ends of the first linear portion.