Planetary Gear Torsional Damper With Homogeneous Tooth Engagement
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Solution Overview
Problem
Existing torsional vibration dampers face issues with gear damage and reduced vibration damping performance due to dimension errors in the planetary gear unit, particularly when manufactured using conventional methods like cutout, which increase costs and time, and press working methods that result in uneven tooth engagement and potential damage.
Innovation Solution
A torsional vibration damper design and manufacturing method where the sun gear, ring gear, and planetary pinion gears are formed using press forming, with each tooth's thickness varied in the face width direction to ensure homogeneous engagement, reducing manufacturing costs and time while minimizing gear damage, and the remaining gears are formed using cutout methods to match the press-formed dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gears are manufactured by press working to reduce manufacturing cost and time, then productivity is improved, but manufacturing precision deteriorates due to plastic deformation creating rollover surfaces and droop surfaces
Solution Approach 1:
The patent applies local quality by making the tooth thickness non-uniform in a controlled manner. Specifically, the tooth thickness is made thinner at one end (where the rollover surface is formed) and thicker at the other end. This deliberate local variation compensates for the plastic deformation effects, ensuring homogeneous contact between mating gears while maintaining the benefits of press working manufacturing.
2Ease of manufacture
If gears are manufactured by press working, then ease of manufacture is improved, but reliability deteriorates due to uneven tooth contact and potential gear damage
Solution Approach 1:
The invention makes the tooth thickness vary locally along the face width direction, with the thickness being smaller at the end where the rollover surface is formed and larger at the opposite end. This local variation ensures that the contact between mating gears is homogeneous across the entire tooth surface, preventing localized stress concentrations and improving gear reliability while maintaining manufacturing simplicity.
3Manufacturing precision
If conventional cutout method is used to shape gear teeth, then manufacturing precision is improved, but productivity deteriorates due to increased manufacturing time and cost
Solution Approach 1:
The patent changes the tooth thickness parameter deliberately to be non-uniform along the face width direction. Instead of maintaining constant thickness as in conventional gears, the thickness is varied to compensate for press working deformation effects. This parameter change allows press working to produce gears with sufficient precision for homogeneous contact, thereby improving productivity without sacrificing the necessary manufacturing precision.
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 ensures homogeneous tooth engagement, reduces gear damage, and maintains vibration damping performance while lowering manufacturing costs and time by using press forming for key components and cutout for others, addressing the challenges of dimension errors and manufacturing inefficiencies.
Implementation Method 1
The input element and the output element are connected to each other through an elastic member so that the input element and the output element are rotated relatively to each other while deforming the elastic member by a pulsation of the torque of the engine
Implementation Method 2
a plurality of planetary pinion gears interposed between the sun gear and the ring gear to transmit a torque
Implementation Method 3
the inertia element is also oscillated by the pulsation of the torque of the engine. A inertia torque of the ring gear thus oscillated acts as a vibration suppressing torque
Data Source
AI summary
A torsional vibration damper that a torsional vibration damper having a planetary gear unit, and a manufacturing method of the torsional vibration damper for limiting damages on gears of the planetary gear unit due to dimension errors. In the planetary gear unit, at least one of a sun gear, a ring gear, and a set of planetary gears is/are formed by a press forming method. The gear formed by the press forming method is engaged with the remaining gears in such a manner that a thinner portion of each tooth is individually engaged with a thicker portion of the adjacent teeth of the remaining gears.