Balancing Shaft Partial Bearing Weight Reduction
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Solution Overview
Problem
Conventional balancer shafts for single or multi-cylinder engines face challenges in reducing total weight and moving masses while maintaining balance compensation, especially with increasing engine speeds.
Innovation Solution
The balancer shaft features a bearing with a radial running surface that extends only partially over the circumference, allowing for significant weight reduction and improved running smoothness, along with a supporting surface that enhances service life and adaptability to different applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a conventional full-circumference bearing is used, then the bearing provides complete support and reliability, but the weight of the balancer shaft increases
Solution Approach 1:
The bearing is segmented into a running surface extending only partially over the circumference (e.g., 120-180 degrees) rather than providing full 360-degree support. This segmentation reduces the bearing material and overall balancer shaft weight while maintaining sufficient support through strategic placement of the running surface and support surfaces at critical locations.
Solution Approach 2:
Instead of uniform bearing support around the entire circumference, the invention applies bearing surfaces locally where needed: a running surface at the location experiencing centrifugal force and support surfaces at opposite locations. This localized quality approach provides adequate support reliability only in the critical areas rather than uniformly throughout, reducing overall weight.
2Weight of moving object
If the bearing point is cut free to reduce weight, then weight savings are achieved, but the running smoothness may be compromised
Solution Approach 1:
The bearing point is segmented by removing material in non-critical areas while retaining the running surface and support surfaces. This creates a partially free-bearing structure that reduces weight while maintaining smooth operation through the preserved bearing surfaces at critical locations.
Solution Approach 2:
The bearing point structure transitions from uniform solid material to a locally optimized structure with bearing surfaces only where needed for smooth operation. The running surface ensures smooth operation during rotation, while support surfaces provide stability during shocks, vibrations, and start-stop conditions.
3Weight of moving object
If the running surface extends partially over the circumference, then weight is reduced, but the bearing coverage is decreased
Solution Approach 1:
Instead of providing full circumferential bearing coverage, the invention uses partial coverage with a running surface extending only over the necessary arc (e.g., 120-180 degrees) where centrifugal force acts. This partial action is sufficient for the application requirements while significantly reducing bearing material and weight.
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 configuration achieves a weight saving of 20 to 40% compared to conventional balancer shafts, maintains balance compensation, and ensures smooth operation and extended service life by optimizing the distribution of centrifugal forces and supporting surfaces.
Implementation Method 1
the resulting centrifugal force during the rotation of the balancer shaft to be in an area of the bearing that is encompassed by the partial running surface
Data Source
AI summary
The invention relates to a balancing shaft for a single- or multi-cylinder motor having at least one unbalanced weight section (21, 22; 23, 24) and at least one bearing point (16, 17), wherein the at least one unbalanced weight section (21, 22; 23, 24) is allocated to the bearing point (16, 17) and the bearing point has a radial contact surface (18) that extends only partially over a circumference of the bearing point (16, 17) and a centrifugal force resulting from the rotation of the balancing shaft (11) lies inside a region of the bearing point (16, 17) formed by the contact surface (18) extending partially over the circumference of the bearing point (16, 17), wherein at least one support surface (51) is provided that is provided partially over the circumference of the bearing point (16, 17) and separately from the contact surface (18).