Axial Piston Dog Clutch Actuation
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Solution Overview
Problem
The existing vehicular power transmitting systems with a dog clutch and synchro-mesh mechanism face instability due to bending forces on the fork shaft, leading to potential deterioration of the oil seal's sealing function and performance.
Innovation Solution
A vehicular power transmitting system with a first piston disposed within the rotary shaft, a sleeve connected to the piston, a synchronizer ring in sliding contact with the clutch gear, and an actuator using a second piston to axially reciprocate the first piston, ensuring coaxial alignment and reducing bending forces, along with an elastic member like a coil spring for disengagement, and a hydraulic actuator for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the fork shaft is disposed radially outwardly of the rotary shaft with a cantilevered shift fork, then the dog clutch can be operated to switch between engaged and released states, but the fork shaft is subjected to bending forces causing deflection and instability
Solution Approach 1:
The invention inverts the conventional arrangement by moving the shift fork from a radial cantilever position to an axial position within the rotary shaft. Instead of the fork shaft extending radially outward, the shift fork now operates axially inside the rotary shaft, fundamentally changing the structural configuration to eliminate bending moments on the fork shaft.
Solution Approach 2:
The invention introduces a piston as an intermediary element between the actuator and the shift fork. The piston transmits the actuating force axially to the shift fork through the rotary shaft, eliminating the need for a radially extending fork shaft and its associated bending forces.
2Ease of operation
If the fork shaft is subjected to bending forces from thrust force, then the dog clutch can be actuated, but the oil seal's sealing function deteriorates and performance becomes unstable
Solution Approach 1:
The piston serves as an intermediary that transmits the actuating force axially through the rotary shaft to the shift fork, eliminating bending forces that would otherwise compromise the oil seal's sealing function and operational reliability.
Solution Approach 2:
The invention replaces the mechanical cantilevered fork shaft system with a hydraulic or pneumatic piston system that operates axially, substituting a force-prone mechanical structure with a more reliable pressure-driven actuation mechanism.
3Device complexity
If a radial fork shaft arrangement is used, then the structure is simple, but bending forces cause deflection and operational instability
Solution Approach 1:
The invention inverts the conventional radial fork shaft arrangement by repositioning the shift fork axially within the rotary shaft. This inversion transforms a simple but unstable radial structure into a more complex yet stable axial configuration that eliminates bending forces.
Solution Approach 2:
The shift fork and piston are nested within the rotary shaft, with the shift fork operating axially inside the rotary shaft's central passage. This nested arrangement consolidates multiple components into a compact, stable configuration that eliminates external bending forces.
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 configuration enhances the operational stability of the dog clutch, reduces the need for oil sealing members, and lowers manufacturing costs by minimizing component complexity and hydraulic pressure losses, while maintaining high efficiency and reliability.
Implementation Method 1
an elastic member disposed between an outer circumferential surface of the first piston and an inner circumferential surface of the rotary shaft to bias the first piston in a direction for disengagement of the internal teeth of the sleeve from the clutch gear
Implementation Method 2
an actuator including a second piston to axially reciprocate the first piston for thereby bringing the internal teeth of the sleeve into meshing engagement with the clutch gear through the synchronizer ring
Data Source
AI summary
A power transmitting system including: a first piston disposed within a center bore formed through the rotary shaft such that the first piston is axially reciprocable; a sleeve connected to the first piston and having internal teeth meshing with the external teeth of the rotary shaft so that the sleeve is rotated with the rotary shaft, and such that the sleeve is axially reciprocable together with the first piston according to axial movements of the first piston; a synchronizer ring supported in sliding contact with an outer circumferential tapered surface of the clutch gear such that the synchronizer ring is rotatable relative to the clutch gear; and an actuator including a second piston to axially advance the first piston for thereby bringing the sleeve's internal teeth into meshing engagement with the clutch gear through the synchronizer ring. The first piston and second piston are disposed coaxially with the rotary shaft.