Vehicle Transmission Snap Ring Retention Design
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Solution Overview
Problem
In vehicle transmissions, snap rings expanded during installation can exit their mounting grooves due to centrifugal forces during operation, preventing the actuation of friction element assemblies, which is a challenge as transmission designs become more complex and make it difficult to avoid using such snap rings.
Innovation Solution
The transmission design incorporates a mounting groove for the snap ring that allows it to expand and contract, with additional features like assembly and operational notches, or the use of snap ring keepers and secondary snap rings to prevent the snap ring from exiting, ensuring it remains in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a snap ring is expanded during installation, then the snap ring can be installed in the mounting groove, but the snap ring may exit the mounting groove due to centrifugal force during operation
Solution Approach 1:
A snap ring keeper is introduced as an intermediary component between the snap ring and the mounting groove. The keeper has a first engagement portion that engages the snap ring and a second engagement portion that engages the mounting groove, thereby preventing the snap ring from exiting the groove while allowing it to be expanded during installation
Solution Approach 2:
The retention function is segmented into two separate components: the snap ring provides initial retention, and the snap ring keeper provides additional retention during operation. This segmentation allows each component to perform its specific function without interfering with the other
2Ease of manufacture
If space is provided for the snap ring to expand during installation, then the snap ring can be installed, but the same space allows the snap ring to expand and exit during rotation
Solution Approach 1:
The snap ring keeper acts as a mediator that restricts the expansion of the snap ring during operation. The keeper's second engagement portion with the mounting groove prevents the snap ring from utilizing the expansion space that would otherwise allow it to exit during rotation
Solution Approach 2:
The snap ring keeper is pre-installed in the mounting groove before the snap ring is expanded and installed. This preliminary positioning creates a constraint that prevents the snap ring from exiting during operation, countering the harmful effect of centrifugal force before it can cause failure
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 allows for the installation of expanded snap rings and prevents them from moving once installed, ensuring the friction element assemblies can be properly actuated and maintained, even under high rotational speeds.
Implementation Method 1
The snap ring is installed into the mounting groove by expanding the snap ring and then allowing the snap to contract and enter the mounting groove
Implementation Method 2
When the friction element assembly associated with the snap ring rotates, a centrifugal force acts on the snap ring, which may cause the snap ring to expand
Data Source
AI summary
A vehicle transmission includes a transmission shaft, a friction element assembly mounted on the transmission shaft, a piston assembly for actuating the friction element assembly, a snap ring for retaining the friction element assembly and a mounting groove formed in the transmission shaft. The snap ring is installed into the mounting groove by expanding the snap ring and then allowing the snap to contract and enter the mounting groove. The mounting groove is located such that the snap ring could exit the mounting groove upon expansion of the snap ring due to a centrifugal force. Accordingly, various arrangements are provided to prevent the snap ring from leaving the mounting groove after installation.