Spline VVT Phase Adjusting Device with Differential Pitch
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Solution Overview
Problem
Existing spline VVT systems for regulating rotational phase between crankshaft and camshaft require complex hydraulic systems or continuous power supply for phase adjustment, which complicates engine design and increases energy consumption.
Innovation Solution
A transmission assembly with a tubular meshing member featuring splines of different pitches and/or groove directions, coupled with a bearing arrangement and actuation member, allows for axial displacement without rotating the meshing member, enabling flexible phase adjustment using a drive unit like a stepper motor, reducing power consumption and simplifying the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydraulic arrangements are used to apply hydraulic pressure on the piston fixed to the center wheel, then axial motion is imparted to the center wheel, but the system becomes complex with multiple rotating components
Solution Approach 1:
The patent replaces the hydraulic arrangement with a purely mechanical transmission assembly. The actuation member with different pitch splines mechanically converts rotational motion to axial displacement of the center wheel, eliminating the need for complex hydraulic systems with rotating components.
Solution Approach 2:
The invention changes the pitch parameter of the splines on the actuation member. By having different pitch values on different sides of the actuation member, a simple rotational input produces differential axial movement that translates to center wheel displacement, achieving the desired function through parameter variation rather than complex system architecture.
2Ease of operation
If a permanent-magnet rotary drum is attached to the center wheel and controlled by electromagnetic clutch, then phase difference is regulated, but continuous power supply is required whenever the engine is running
Solution Approach 1:
The patent employs periodic action by using a spring-loaded actuation member that is intermittently engaged. The spring stores energy and provides periodic engagement with the splined member, allowing phase adjustment only when needed rather than continuous power consumption. This converts continuous control into periodic, on-demand adjustment.
Solution Approach 2:
The invention introduces dynamic elements through the spring-loaded actuation mechanism. The spring allows the actuation member to dynamically engage and disengage from the splined member based on operational needs, enabling the system to transition between active control and passive maintenance states, thereby reducing overall energy consumption.
3Ease of operation
If the center wheel is displaced axially to rotate the inner wheel with respect to the outer wheel, then phase lag or lead is achieved, but the mechanism requires complex arrangements to impart axial displacement
Solution Approach 1:
The patent utilizes helical (curved) splines on the actuation member instead of straight splines. The helical geometry converts simple rotational movement of the actuation member into axial displacement, achieving phase adjustment through geometric conversion rather than complex mechanical arrangements. The curvature of the helical spline is key to the mechanism's simplicity and effectiveness.
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 solution provides a flexible and energy-efficient means to adjust the rotational phase between the crankshaft and camshaft, reducing power consumption and simplifying the system design by separating axial displacement from meshing member rotation, allowing rapid and accurate phase changes.
Implementation Method 1
a bearing arrangement (46) arranged between the meshing member (36) and the actuation member (48) so as to allow a transfer of an axial displacement of the actuation member (48) to the meshing member (36) and to allow a rotation of the meshing member (36) relative to the actuation member (48)
Implementation Method 2
at least a portion of the inner surface is provided with a first spline (42) and at least a portion of the outer surface is provided with a second spline (44). The first spline (42) and the second spline (44) do not have the same pitch in the same direction
Data Source
AI summary
The invention relates to a transmission assembly (34), for imparting a phase difference between an outer wheel and an inner wheel of a spline VVT. The assembly comprises a tubular meshing member (36) having an inner surface (38) and an outer surface (40), wherein at least a portion of the inner surface is provided with a first spline (42) and at least a portion of the outer surface is provided with a second spline (44). The first spline and the second spline do not have the same pitch in the same groove direction. The transmission assembly further comprises a bearing arrangement (46) and an actuation member (48). The bearing arrangement is arranged between the meshing member and the actuation member to allow a transfer of an axial displacement of the actuation member to the meshing member and allow a rotation of the meshing member relative to the actuation member.