Valve Timing Control Device Compact Configuration
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Solution Overview
Problem
Existing valve opening/closing timing control devices are bulky due to expanded components and increased load on bearings, leading to larger dimensions and potential wear issues, necessitating a more compact configuration that maintains smooth operation and effective lubrication.
Innovation Solution
A compact configuration utilizing a driving-side rotating body synchronized with a crankshaft, a driven-side rotating body, and a phase adjustment mechanism with an Oldham coupling, eccentric member, and strategically placed bearings and lubrication grooves to stabilize the rotational attitude and facilitate lubricant discharge, reducing dimensions and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bearing is disposed on the front case side to support the eccentric member, then the rotational support function is achieved, but the load on the front case increases and the device size increases
Solution Approach 1:
The bearing is relocated from the front case side to the rear side of the camshaft, changing the spatial arrangement from front-to-back support to rear-to-front support. This dimensional repositioning allows the bearing to support the eccentric member without increasing front case load or overall device size, as the bearing is now integrated into the rear structure rather than requiring front case expansion.
2Reliability
If the cover member or front case is expanded outward to support the eccentric member through a bearing, then the bearing support function is achieved, but the device dimensions increase
Solution Approach 1:
The bearing is nested within the rear structure of the camshaft assembly rather than requiring external expansion of the front case or cover member. The bearing is positioned in the rear portion and supports the eccentric member from behind, allowing the eccentric member to be accommodated within the existing device envelope without increasing the overall length or requiring case expansion.
3Power
If a large load acts on the gears, then the gear transmission function is achieved, but wear of tooth surfaces increases and lubrication becomes critical
Solution Approach 1:
Lubricating oil is supplied to the gear tooth surfaces before the gears engage under full load. The lubrication system is designed to deliver oil to the meshing points of the gears in advance, ensuring that a lubricating film is already present on the tooth surfaces when the large transmission loads are applied, thereby preventing wear and ensuring reliable operation under power transmission conditions.
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 configuration achieves a more compact size while ensuring smooth operation and effective lubrication, reducing wear and maintaining durability by stabilizing the rotational attitude and efficiently discharging lubricants, thus addressing the bulkiness and wear concerns of previous devices.
Implementation Method 1
an input gear configured to couple to the driving-side rotating body through an Oldham coupling
Implementation Method 2
the phase adjustment mechanism changing a position where the output gear and the input gear engage with each other by causing the eccentric axis to revolve with rotation of the eccentric member
Implementation Method 3
a cylindrically-shaped eccentric member that supports the input gear inside of the input gear so as to allow the input gear to rotate around the eccentric axis
Data Source
AI summary
A valve opening/closing timing control device that sets a relative rotation phase between a driving-side rotating body and a driven-side rotating body using a driving force of an electric actuator is compactly configured. The device is provided with: a first bearing disposed between an inner periphery of the driven-side rotating body and an eccentric member; a second bearing disposed between the eccentric member and an input gear on a side of the first bearing away from a camshaft in a direction along a rotational axis; and a front plate fixed to the driving-side rotating body on a side of the second bearing away from the camshaft. An Oldham coupling is disposed on the side away from the camshaft of both the first bearing and the second bearing in the direction along the rotational axis.