Valve Timing Controller Input Wall Deformation Control
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Solution Overview
Problem
Existing valve timing controllers for internal combustion engines face issues with deformation of the input wall during assembly, leading to increased supporting backlash, abrasion, noise, and reduced bearing life due to varying rigidity and distortion of the fitting recess.
Innovation Solution
A valve timing controller design featuring a cylindrical input wall with a thin-wall portion in the radial direction, arranged apart from the fitting recess, reduces circumferential deformation and enhances assembly fit and anti-wear quality, while maintaining bearing roundness and extending its lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the input wall is press-inserted into the bearing member to reduce supporting backlash, then the supporting backlash is reduced, but the input wall deforms due to varying rigidity caused by the fitting recess
Solution Approach 1:
The input wall is designed with a thin-wall portion at a specific location (opposite to the fitting recess) to create localized rigidity variation. This allows the press-fit to be applied uniformly while the thin-wall portion specifically counteracts the deformation tendency caused by the fitting recess, maintaining overall circularity and reducing input wall distortion.
Solution Approach 2:
The thin-wall portion is positioned in advance at the location opposite to the fitting recess to preemptively counteract the deformation that would occur during press-fit assembly. This preliminary structural arrangement creates a balancing effect that prevents the input wall from deforming into an elliptical shape during installation.
2Reliability
If the input wall is press-inserted into the bearing member, then the supporting backlash is reduced, but the fitting recess distorts causing assembly time increase and vibration
Solution Approach 1:
By adding the thin-wall portion at a specific location, the local rigidity is adjusted to prevent excessive deformation of the fitting recess during press-fit. This maintains the geometric accuracy of the fitting recess, enabling smooth and quick engagement with the joint member without distortion-induced assembly delays.
Solution Approach 2:
The thin-wall portion is pre-formed in the input wall before assembly to prevent fitting recess distortion during the press-fit process. This preliminary structural preparation ensures that the fitting recess maintains its original geometry, allowing the joint member to engage smoothly and quickly without vibration or assembly delays.
3Reliability
If the input wall is press-inserted into the bearing member, then the supporting backlash is reduced, but the bearing member roundness deteriorates reducing its lifetime
Solution Approach 1:
The thin-wall portion creates a localized rigidity feature that balances the overall structural rigidity of the input wall. This prevents excessive deformation transfer to the bearing member during press-fit, maintaining the bearing member's roundness and extending its service life while still achieving the goal of reducing supporting backlash.
Solution Approach 2:
The thin-wall portion is designed in advance to counteract the deformation tendency that would otherwise be transferred to the bearing member. By preemptively balancing the rigidity distribution, the input wall structure prevents deterioration of the bearing member's roundness, thereby protecting the bearing member's lifetime.
Data Source
AI summary
A valve timing controller has a shaft body as an output rotor, a torque generating system which generates the controlling torque outputted from the shaft body, and a planet carrier as an input rotor connected with the shaft body. A phase adjusting mechanism adjusts the relative rotational phase between a crankshaft and a camshaft according to the control torque inputted into the planet carrier from the shaft body. A bearing rotatably supports the planet carrier. The planet carrier forms a cylindrical input wall press-inserted in an inner circumference of the bearing. The input wall is provided with a fitting recess on its inner surface for engaging with the shaft body, the input wall is provided with a thin-wall portion of which thickness is reduced in a radial direction, and the fitting recess and the thin-wall portion are circumferentially arranged apart from each other.