Rotary Transmission Coupling with Non-Rotating Hydraulic Actuator
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Solution Overview
Problem
Existing four-wheel drive systems in vehicles require manual engagement and rely on wheel slippage to activate four-wheel drive mode, which is inefficient and not independently controllable.
Innovation Solution
A hydraulically operable rotary transmission coupling with a friction clutch and actuator assembly that allows independent control through external hydraulic pressure, eliminating the need for wheel slippage and manual engagement, featuring spigots for fluid supply and return and a non-rotating actuator body to manage clutch operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a speed differential pump arrangement is used to activate 4WD, then the system can automatically engage four-wheel drive based on wheel slippage detection, but 4WD is only actuated when actual slipping occurs which delays the response and reduces controllability
Solution Approach 1:
The patent applies preliminary action by using a remote pump that can be activated in advance or independently of wheel slippage detection. The pump can supply hydraulic pressure to engage the friction clutch before actual slipping occurs, allowing the system to proactively engage 4WD based on predicted conditions or driver input, thereby eliminating the response delay inherent in reactive slippage-based systems.
2Ease of operation
If a manual shift operated by the vehicle driver is used to engage 4WD, then the driver has direct control over four-wheel drive engagement, but the system requires manual intervention which reduces convenience and increases operational complexity
Solution Approach 1:
The patent extracts the hydraulic actuation mechanism from the manual shifting system by introducing a remote pump and hydraulic actuator assembly that can independently engage the friction clutch. This separates the clutch engagement function from the manual gear shift operation, allowing 4WD engagement to be controlled hydraulically either automatically or through simplified driver input, thereby reducing operational complexity while maintaining control.
3Adaptability or versatility
If the actuator body is allowed to rotate with the clutch housing, then the hydraulic actuator components are subject to rotational forces and complex loading conditions, but this complicates the bearing arrangement and reduces reliability
Solution Approach 1:
The patent introduces a non-rotating actuator body as an intermediary between the rotating clutch housing and the hydraulic piston. This non-rotating body is supported by bearings that interface with the rotating clutch housing, effectively mediating the rotational motion and converting it into linear piston movement. This arrangement protects the hydraulic components from rotational forces, simplifies the bearing arrangement, and enhances reliability by isolating the actuator mechanism from rotational dynamics.
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
Enables independent and efficient control of four-wheel drive without relying on wheel slippage, reducing the need for manual intervention and enhancing adaptability by using external hydraulic power to manage torque distribution to all wheels.
Implementation Method 1
a friction clutch for selectively coupling the rotary output to the rotary input and an actuator assembly responsive to hydraulic pressure
Implementation Method 2
a friction clutch for selectively coupling the rotary output to the rotary input
Data Source
Figure 1
Figure 2
Figure 3b
AI summary
A rotary transmission coupling (1) is disclosed for selectively providing drive to an output such as a driven wheel (115, 116) of a motor vehicle (100). The rotary transmission coupling (1) includes a friction clutch (2) and a hydraulic actuator assembly (20) that receives fluid at pressure from a remote pump (206, 216) controlled by an electronic control unit (202). The actuator assembly (20) includes a hydraulic actuator formed by a body (21) that slidingly supports a piston (25) used to operate the friction clutch (2). The body (21) is restrained from rotation by a number of spigots (24, 35, 36) that allow limited translation of the body (21) to accommodate tolerance build-up within a transmission assembly (123) of which the rotary coupling (1) forms a part. The hydraulic actuator is attached to a clutch cover (4) of the friction clutch (2) such that the reaction force from the hydraulic actuator is resisted solely by the clutch cover (4) and is not transferred to any other components of the rotary transmission coupling (1).