Toroidal CVT Trunnion Oil Passage Layout for Shorter Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In toroidal continuously variable transmissions, the hydraulic actuator and lubricating oil passage configuration lead 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 shaft, with a cylinder forming pressure chambers and lubricating oil passages that communicate through a third passage between the pistons, allowing for a more compact design by overlapping oil and pressure passages, and utilizing 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 the direction along the axis of the trunnion, then the lubrication function is achieved, but the shaft portion and cylinder become long in the axial direction
Solution Approach 1:
The patent repositions the inflow port of the lubricating oil passage from an axial arrangement to a radial arrangement on the cylindrical surface of the shaft portion. This dimensional change allows the lubricating oil passage to communicate with the hydraulic actuator through the wall thickness of the shaft portion rather than through axial extension, thereby reducing the axial length while maintaining the lubrication function.
Solution Approach 2:
The lubricating oil passage is formed as a through-hole penetrating the shaft portion radially, with the inflow port positioned on the cylindrical surface. This nested configuration allows the lubrication system to be integrated within the shaft portion structure itself, eliminating the need for separate axial extensions and reducing overall component length.
2Length of stationary object
If the shaft portion and cylinder are reduced in size in the axial direction, then the compactness is improved, but the lubricating oil passage configuration becomes more difficult
Solution Approach 1:
By moving the lubricating oil passage configuration from the axial dimension to the radial dimension, the patent enables the use of standard cylindrical machining operations to create the through-hole. This approach simplifies manufacturing compared to creating complex axial passages in a compacted structure, as radial holes can be drilled or bored through the shaft portion wall thickness using conventional methods.
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 shaft portion and cylinder while maintaining effective lubrication and load balance, preventing interference and unbalanced sealing pressures, and allowing for efficient transmission ratio adjustments.
Implementation Method 1
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
Implementation Method 2
The shaft portion includes a second lubricating oil passage through which the lubricating oil flows toward the power roller
Data Source
Figure 1
Figure 2
Figure 3~4
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.