Dog Clutch Bypass for Variator Locking
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Solution Overview
Problem
Infinitely variable transmissions face challenges in controlling torque output variability, as existing dog clutches do not effectively lock the input and output rings to prevent continuously-varying torque, leading to inefficiencies in gear ratio changes.
Innovation Solution
A dog clutch system with a housing and piston configuration that engages and disengages with the input and output rings of a variable-ratio unit, utilizing hydraulic fluid and a spring mechanism to control the piston's movement between disengaged and engaged positions, allowing for the locking of input and output rings to produce a fixed torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dog clutch is used to lock the input and output rings of a variable-ratio unit, then the continuously-varying torque output can be prevented, but the existing dog clutch designs do not effectively lock the rings leading to transmission inefficiency
Solution Approach 1:
The patent employs a hydraulic piston mechanism to engage and disengage the dog clutch. Hydraulic fluid is supplied to the piston to move it into the engaged position, where it locks the input and output rings together. This hydraulic actuation provides reliable and effective locking while maintaining transmission efficiency through controlled engagement and disengagement.
2Adaptability or versatility
If the piston is moved to engage the output ring to lock the input and output rings, then a fixed torque output is produced, but the mechanism complexity increases with hydraulic fluid and spring components
Solution Approach 1:
The piston mechanism serves multiple functions: it engages and disengages the dog clutch, locks the input and output rings, and enables switching between continuously-varying and fixed torque output modes. The hydraulic system and spring work together to provide both actuation and maintaining of the engaged state, consolidating control functions into a single integrated mechanism.
Solution Approach 2:
The hydraulic fluid acts as an intermediary to transmit force to the piston, enabling controlled engagement of the dog clutch. The spring serves as a mechanical intermediary to maintain the piston in the engaged position and provide the necessary force to lock the rings. These intermediary elements facilitate the complex locking action without requiring direct mechanical linkage.
3Productivity
If the dog clutch fails to effectively prevent continuously-varying torque, then gear ratio changes are inefficient, but increasing the locking force may damage the variable-ratio unit
Solution Approach 1:
The dog clutch engagement is designed to be dynamic and controlled through hydraulic actuation. The piston can be smoothly engaged and disengaged by controlling hydraulic fluid supply, allowing the locking force to be applied gradually and uniformly. This dynamic engagement prevents sudden shock loads that could damage the variable-ratio unit while ensuring effective locking for efficient gear ratio changes.
Solution Approach 2:
The spring mechanism provides cushioning by maintaining constant contact force between the piston and the engagement surfaces. This pre-applied spring force ensures smooth engagement without impact shocks, protecting the variable-ratio unit from damage while enabling reliable locking when the clutch is engaged.
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 system effectively bypasses the variator to produce a fixed torque output, enhancing control over gear ratio changes and reducing variability, thereby improving transmission efficiency.
Implementation Method 1
a spring in the second cavity configured to exert a biasing force on the piston as the piston moves between the first and second positions
Implementation Method 2
Hydraulic fluid is provided to the first cavity to move the piston from the first position to the second position
Implementation Method 3
Hydraulic fluid is provided to the second cavity to exert a force to counteract the biasing force of the spring as the piston moves between the first and second positions
Data Source
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AI summary
A dog clutch operable to bypass a variator of a transmission is disclosed. The dog clutch includes a housing engaged with an input ring of the variator. The dog clutch also includes a piston engaged with the housing and movable from a first position in which the piston is disengaged from an output ring of the variator to a second position in which the piston is engaged with the output ring. The variator input ring and output ring are locked together when the dog clutch is in the second position to prevent the variator from producing continuously variable torque output. The variator is operable to produce continuously-variable torque output when the dog clutch is in the first position.