Variable Two-Way Over-Running Clutch Eliminates Spinning Losses
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Solution Overview
Problem
Conventional transmission clutches, particularly planetary automatic transmissions, suffer from inefficiencies due to drag-related losses in wet clutches and abrupt gear shifts in switch-type clutches, leading to reduced efficiency, increased noise, vibration, and harshness.
Innovation Solution
A clutch assembly featuring a two-way over-running clutch with an inner and outer race, torque transmitting members, and an actuator that controls radial movement to selectively engage and disengage the clutch, eliminating spinning losses and allowing gradual torque transfer, thereby improving efficiency and reducing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wet clutches are used in planetary automatic transmissions, then smooth gear shifts are achieved through gradual torque transfer, but spinning losses occur when friction plates are disengaged
Solution Approach 1:
A one-way clutch mechanism is introduced as an intermediary between the input shaft and output shaft. This one-way clutch allows free rotation in one direction while preventing reverse rotation, thereby eliminating the need for friction plates to spin during disengagement while still enabling smooth torque transfer during engagement through gradual contact of friction surfaces.
Solution Approach 2:
The clutch assembly dynamically transitions between two operational states: an engaged state where friction plates contact to provide gradual torque transfer for smooth shifts, and a disengaged state where the one-way clutch mechanism takes over to prevent spinning losses while maintaining rotational freedom. This dynamic state change resolves the contradiction between smooth operation and energy loss.
2Loss of energy
If dog clutch or switch-type clutch arrangements are used, then efficiency is improved by eliminating spinning losses, but abrupt gear shifts occur due to lack of gradual energy dissipation
Solution Approach 1:
The invention merges two previously separate clutch mechanisms into a single integrated assembly: a one-way clutch for eliminating spinning losses and a friction plate clutch for providing gradual torque transfer. The friction plates are positioned between the input shaft and output shaft within the same housing as the one-way clutch, allowing both mechanisms to work together in coordinating fashion to achieve both efficiency and smooth operation.
3Loss of energy
If adequate spacing is provided between friction plates, then spinning losses are minimized, but shift time increases and packaging dimensions become larger
Solution Approach 1:
The clutch assembly is segmented into multiple friction plates arranged in a compact stack, with each plate contributing to the overall torque transfer capability. This segmentation allows the friction plates to be positioned close together without requiring excessive spacing, as the cumulative effect of multiple plates provides sufficient torque transfer while maintaining compact dimensions and rapid shift response.
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 clutch assembly enhances efficiency by eliminating spinning losses, provides smoother shifts, and reduces noise and vibration compared to conventional wet and switch-type clutch systems.
Implementation Method 1
The at least one cam has a ramped surface configured to contact the at least one torque transmitting member
Data Source
AI summary
A clutch assembly is provided that includes a first shaft, a second shaft, a housing, a two-way over-running clutch, and a friction clutch assembly. The two-way over-running clutch includes an inner race and an outer race. At least one torque transmitting member is disposed between the inner race and the outer race that selectively transfers torque from the inner race to the outer race. The inner race defines at least one cam that receives the torque transmitting member. An inner race actuator selectively controls lock-up of the two-way over-running clutch by moving the inner race relative to the first shaft and the outer race between a concentric position and at least one eccentric position.