Valve Timing Controller Offset Contact
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Solution Overview
Problem
Existing valve timing controllers experience reduced control performance due to intermittent torque transmission and increased friction resistance, leading to hysteresis and stick-slip phenomena, which affect the reciprocation of the movable body and ultimately the spool control valve.
Innovation Solution
The valve timing controller incorporates a linear solenoid with a movable core and output shaft that uses a concave surface on the output shaft to contact a sphere-shaped end face of the spool, offset in the radial direction, allowing for efficient torque transmission and reduced friction resistance, thereby minimizing hysteresis and stick-slip effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the spool contacts the output shaft with a sphere-shaped end face on a flat end surface, then the spool can be simply structured, but the torque transmission becomes intermittent and friction resistance increases
Solution Approach 1:
The patent applies spheroidality by changing the contact surface geometry from a flat surface to a curved surface. The output shaft is provided with a curved surface that contacts the sphere-shaped end face of the spool, enabling continuous torque transmission while maintaining simple structure. The curved surface allows the spool to maintain rotational contact throughout its reciprocation motion, eliminating the intermittent torque transmission that occurs with flat surface contact.
2Ease of operation
If the spool contacts the output shaft at the center axis position, then the alignment is simple, but the torque transmission efficiency is reduced and hysteresis increases
Solution Approach 1:
The patent applies asymmetry by offsetting the contact position from the center axis of the spool. The curved surface on the output shaft is positioned such that the sphere-shaped end face contacts it at a position offset from the spool's center axis. This asymmetric contact position improves torque transmission efficiency and reduces hysteresis in the reciprocation motion, while the curved surface geometry maintains alignment simplicity.
3Device complexity
If the movable body reciprocates from a static-friction state, then the structure is simple, but the friction resistance becomes large and stick-slip occurs
Solution Approach 1:
The curved surface contact geometry enables the spool to maintain continuous rotational motion during reciprocation, keeping the friction state dynamic rather than static. This continuous rotation prevents the movable body from starting from a static-friction state, thereby reducing friction resistance and eliminating stick-slip phenomena without requiring additional friction control structures.
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 control performance of the valve timing controller by ensuring continuous torque transmission and reducing friction resistance, eliminating hysteresis and stick-slip, resulting in improved controllability of the spool and valve timing.
Implementation Method 1
The coil generates a magnetic flux by being supplied with electricity. The magnetic flux passes through the cylindrical fixed core and the movable core.
Implementation Method 2
The magnetic flux generated by a coil passes through a movable core and a fixed core, thereby reciprocating an output shaft in an axial direction together with the movable core.
Data Source
AI summary
A valve timing controller has a control valve and a linear solenoid. The control valve is disposed in an interlocking rotor constructed by a vane rotor and a camshaft. The linear solenoid includes a movable member having an output shaft, and a bearing portion supporting the movable member to reciprocate and rotate. A spool of the control valve is contact with the output shaft. The output shaft contacts a sphere-shaped end surface of the spool, at a contact position offset in a radial direction from a center axis of the spool.