Valve Timing Controller Single-Row Planet Bearing
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Solution Overview
Problem
Existing valve timing controllers face challenges in minimizing abnormal noise and wear while being downsized, as they struggle to maintain precise engagement and balance under fluctuating cam torque, leading to potential tilting of the planet gear and associated noise and wear issues.
Innovation Solution
A valve timing controller design featuring a single-row planet bearing with spherical rolling elements and an elastic component that generates a restoring force, ensuring stable positioning of the planet gear through a thrust bearing and carefully positioned rolling contact point, which distributes the restoring force effectively to maintain balance and prevent tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-row planet bearing is used to support the planet gear, then smooth planet movement is achieved, but the device size increases
Solution Approach 1:
The planet bearing is divided into two functional parts: a radial bearing component that supports radial loads and enables smooth planet movement, and a thrust bearing component that supports axial loads. This segmentation allows the use of a simpler single-row structure instead of a complex double-row bearing, reducing device size while maintaining smooth operation.
Solution Approach 2:
The planet bearing is designed to perform multiple functions simultaneously - supporting both radial and axial loads - through the combination of the radial bearing portion and thrust bearing portion. This multi-functionality eliminates the need for separate bearing components, downsizing the overall device while maintaining reliable planet gear support.
2Stability of the object's composition
If the planet gear is supported from both sides in the axial direction, then stability is improved, but the device complexity increases
Solution Approach 1:
The axial support function is extracted from the planet bearing and assigned to a dedicated thrust bearing portion. This separation allows the radial bearing to focus on enabling smooth planet movement while the thrust bearing handles axial stability, reducing overall device complexity through functional specialization.
Solution Approach 2:
The thrust bearing portion acts as an intermediary component between the planet gear and the housing, providing axial support without requiring complex dual-sided support structures. This intermediary element simplifies the support system while maintaining planet gear stability.
3Reliability
If the rolling contact point is positioned to optimize force distribution, then abnormal noise and wear are restricted, but the manufacturing precision requirements increase
Solution Approach 1:
The outer wheel is designed with a specific contact angle at the rolling contact point, creating local geometric optimization. This local quality feature ensures optimal force distribution between the planet gear and outer wheel, restricting abnormal noise and wear while maintaining reasonable manufacturing tolerances through localized design rather than global precision requirements.
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 solution effectively restricts abnormal noise and wear by ensuring stable engagement and force balance across engagement portions, allowing the valve timing controller to be downsized without compromising performance, even under fluctuating cam torque conditions.
Implementation Method 1
The elastic component is interposed between the inner wheel and the planet carrier to generate a restoring force that biases the planet gear to the eccentric side through the planet bearing
Implementation Method 2
The planet bearing has a single row of spherical rolling elements arranged between an outer wheel and an inner wheel
Implementation Method 3
The driving rotor or the driven rotor has a thrust bearing part that supports the planet gear from one side in the axial direction
Implementation Method 4
The outer wheel is in contact with the spherical rolling element at a rolling contact point and defines a contact angle on the one side in the axial direction
Data Source
AI summary
A planet bearing has a single row of spherical rolling elements between an outer wheel and an inner wheel. A planet gear is supported by the outer wheel from a radially inner side. A planet carrier supports the inner wheel from a radially inner side. An elastic component is interposed between the inner wheel and the planet carrier. A driving rotor or a driven rotor has a thrust bearing part that supports the planet gear from one side in the axial direction. The outer wheel is in contact with the spherical rolling element at a rolling contact point and defines a contact angle on the one side in the axial direction.