Toroidal CVT Trunnion Layout for Compact Lubrication Actuation
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Solution Overview
Problem
In toroidal continuously variable transmissions, the hydraulic actuator and lubricating oil passage configuration leads to an elongation of the shaft portion and cylinder in the direction along the axis, necessitating a reduction in size while maintaining effective lubrication.
Innovation Solution
The configuration includes first and second pistons attached to the trunnion's shaft portion, with a cylinder forming pressure chambers and lubricating oil passages that communicate through a relay passage between the pistons, allowing for a more compact design by optimizing the use of space along the axis and incorporating sealing members to manage lubrication and balance loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic actuator and inflow port of the lubricating oil passage are arranged side by side in a direction along an axis of the trunnion, then the lubrication function is achieved, but the shaft portion of the trunnion and the cylinder become long in the direction along the axis
Solution Approach 1:
The patent transitions from a one-dimensional axial arrangement to a two-dimensional planar arrangement by positioning the inflow port and hydraulic actuator side-by-side in the radial direction rather than end-to-end in the axial direction. This dimensional change allows the lubricating oil passage and hydraulic actuator to share the same axial space, thereby reducing the overall axial length of the shaft portion and cylinder while maintaining effective lubrication delivery to the power roller.
2Reliability
If the hydraulic actuator and inflow port of the lubricating oil passage are arranged side by side in a direction along an axis of the trunnion, then the lubrication function is achieved, but the cylinder becomes long in the direction along the axis
Solution Approach 1:
The patent merges the lubrication function and hydraulic actuation function into a single integrated spatial arrangement. By positioning the inflow port of the lubricating oil passage adjacent to the hydraulic actuator along the radial direction, both systems share the same axial envelope, allowing the cylinder to accommodate both functions without requiring extended axial length. This merging of functions reduces the cylinder's axial dimension while ensuring both lubrication and actuation perform their roles effectively.
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 reduces the size of the trunnion's shaft portion and cylinder in the axial direction while ensuring effective lubrication and load balance, preventing interference and unbalanced sealing pressures, and allowing for independent movement of pistons to absorb unbalanced loads.
Implementation Method 1
a hydraulic actuator is configured such that a piston including a piston main body portion and a boss portion is accommodating in a cylinder
Implementation Method 2
a lubricating oil passage is formed inside a shaft portion of the trunnion, and lubricating oil flowing through the lubricating oil passage is discharged toward the power roller
Data Source
AI summary
A toroidal continuously variable transmission includes: first and second pistons attached to a shaft portion of a trunnion so as to be externally fitted to the shaft portion, the first and second pistons being arranged so as to be lined up in a direction along a tilt axis; and a cylinder forming a first pressure chamber which makes the first piston move toward a first side in the direction along the tilt axis and a second pressure chamber which makes the second piston move toward a second side in the direction along the tilt axis. The cylinder includes a first lubricating oil passage, and the shaft portion of the trunnion includes a second lubricating oil passage. A third lubricating oil passage through which the first lubricating oil passage communicates with the second lubricating oil passage is formed between the first piston and the second piston.