Compact Valve Timing Lock Pin via Radial Hydraulic Actuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional valve timing control apparatuses for internal combustion engines require a large space for the lock pin, limiting the freedom of layout due to the need for a large-diameter flange to accommodate the lock pin's retreat movement, which restricts the compact design and installation of the system.
Innovation Solution
The apparatus employs a lock mechanism with first and second lock members and a communication passage to establish fluid communication between lock concave portions, allowing the lock members to retreat against a biasing force, thereby minimizing the size of the lock pin and enhancing layout flexibility by eliminating the need for a large-diameter flange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large-diameter flange is integrally formed on the lock pin to accommodate hydraulic pressure for retreat movement, then the lock pin can be reliably unlocked, but the space required for the lock pin increases, causing limitation in layout
Solution Approach 1:
The lock pin is divided into two functional segments: a lock protrusion for engagement with the lock hole, and a separate pressure receiving surface on its lateral surface. This segmentation eliminates the need for a large flange by distributing functions to different parts of the lock pin structure.
Solution Approach 2:
The hydraulic pressure is applied not axially (through the lock pin length) but radially (on the lateral surface). This dimensional change in pressure application allows the lock pin to be shorter and smaller in volume while still achieving reliable unlocking.
2Volume of moving object
If the lock pin is made smaller to enhance layout freedom, then the valve timing control apparatus becomes more compact, but the hydraulic pressure may not be sufficient to overcome the biasing force for retreat movement
Solution Approach 1:
The lock pin is designed with a locally enlarged pressure receiving surface on its lateral surface, specifically positioned to receive hydraulic pressure. This local quality enhancement ensures sufficient force application area without increasing the overall lock pin volume.
Solution Approach 2:
The design changes the parameter of pressure application from axial to radial direction, and optimizes the surface area distribution on the lock pin to maximize the hydraulic force effectiveness while maintaining compact dimensions.
3Reliability
If the lock pin is positioned to maintain intermediate phase position for engine startability, then engine startability is enhanced, but the lock pin requires precise positioning and control mechanisms
Solution Approach 1:
The lock pin integrates multiple functions into a single component: it provides the locking action through its protrusion, receives hydraulic pressure for unlocking, and maintains the intermediate phase position. This merging reduces the need for separate control mechanisms.
Solution Approach 2:
The lock pin is designed to automatically engage with the lock hole at the intermediate phase position through its geometric configuration and spring biasing, without requiring complex active control systems. The system self-regulates the positioning through the interaction of the lock pin protrusion with the lock hole geometry.
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 design allows for a more compact and flexible layout of the valve timing control apparatus, enabling efficient operation and improved startability of the engine by maintaining the lock pin in an intermediate phase position between maximum phase-retard and phase-advance positions without the need for a large flange, thus enhancing engine performance and installation options.
Implementation Method 1
a hydraulic pressure that acts on a tip end portion of each of the first lock member and the second lock member, the hydraulic pressure being supplied separately from the working fluid pressure selectively supplied to the phase-advance hydraulic chambers and the phase-retard hydraulic chambers
Implementation Method 2
a communication passage formed in the vane rotor so as to extend along a circumferential direction of the vane rotor, the communication passage serving to always establish fluid communication between the first lock concave portion and the second lock concave portion and introduce the hydraulic pressure to allow the first lock member and the second lock member to retreat from the first lock concave portion and the second lock concave portion against the biasing force of the biasing member
Implementation Method 3
the first lock member and the second lock member being urged to project toward a side of the housing by a biasing member and allowed to retreat against a biasing force of the biasing member
Implementation Method 4
the vane rotor being rotatable relative to the housing toward a phase-advance side and a phase-retard side by a working fluid pressure that is selectively supplied to the phase-advance hydraulic chambers and the phase-retard hydraulic chambers and discharged therefrom
Data Source
AI summary
A valve timing control apparatus including a housing, a vane rotor rotatable relative to the housing toward a phase-advance side and a phase-retard side, a first lock member and a second lock member disposed on the vane rotor, a first lock concave portion disposed on the housing so as to be engaged with a tip end portion of the first lock member, a second lock concave portion disposed on the housing so as to be engaged with a tip end portion of the second lock member, and a communication passage formed in the vane rotor and serving to always establish fluid communication between the first and second lock concave portions.