Intermediate Gear Overlap Structure to Prevent Gear Jump-Out
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Solution Overview
Problem
Existing transmissions in heavy-duty vehicles face challenges in preventing unintended disengagement or gear jump-out of intermediate gears, particularly when torque is transferred, leading to potential mechanical failures and inefficiencies.
Innovation Solution
The transmission design incorporates an intermediate gear with primary and secondary intermediate parts that are axially offset, forming an overlap with primary teeth to prevent disengagement. This design ensures that the intermediate gear remains engaged, even under torque transfer conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional intermediate gear design is used, then the transmission structure is simpler, but the intermediate gear may unintentionally disengage or jump out when torque is transferred
Solution Approach 1:
The intermediate gear tooth is divided into two axially offset parts: a primary intermediate part that engages with the primary gear, and a secondary intermediate part that extends axially beyond the primary part. This segmentation allows each part to serve a specific function - the primary part for torque transfer and the secondary part for preventing disengagement, thereby resolving the contradiction between reliability and complexity.
Solution Approach 2:
The secondary intermediate part is designed to protrude axially beyond the primary intermediate part in advance, creating an overlap with the primary gear tooth before any disengagement can occur. This preliminary geometric configuration prevents unintended disengagement by physically blocking the disengagement path, ensuring engagement stability without requiring complex additional mechanisms.
2Reliability
If the intermediate gear is designed with disengagement prevention features, then gear jump-out is prevented, but the transmission becomes more complex
Solution Approach 1:
The disengagement prevention function is merged into the intermediate gear tooth structure itself by creating a secondary intermediate part that is axially offset from the primary intermediate part. This integrated design eliminates the need for separate disengagement prevention mechanisms, thereby maintaining reliability while minimizing additional complexity. The overlap between the secondary intermediate part and primary gear tooth provides inherent disengagement protection.
3Power
If the secondary intermediate part contacts the secondary gear, then torque transfer is enabled, but the intermediate gear may disengage without overlap
Solution Approach 1:
The solution moves from a single-dimensional engagement (primary intermediate part contacting primary gear) to a two-dimensional engagement configuration by adding the secondary intermediate part that extends axially. This axial offset creates an overlap in the axial dimension, enabling torque transfer to the secondary gear while simultaneously providing disengagement prevention through the geometric overlap, thus resolving the contradiction between power transmission and engagement stability.
Data Source
AI summary
A transmission includes a primary gear including primary teeth, each having a primary surface; a secondary gear including secondary teeth; an intermediate gear including intermediate teeth, each comprising a primary intermediate part having a primary intermediate surface and a secondary intermediate part having a secondary intermediate surface, where the primary intermediate part is axially offset from the secondary intermediate part. The intermediate gear is axially displaceable to an engaged position. The primary surface contacts the primary intermediate surface in a contact region and the secondary intermediate surface contacts one of the secondary teeth. In the engaged position, one primary tooth and one intermediate tooth form an overlap, radially inside the contact region, for preventing the intermediate gear from being displaced from the engaged position to a disengaged position.