Planetary Gear Bearing Layout for Compact Hand-Held Gear Units
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Solution Overview
Problem
Existing hand-held power tool transmission units are not compact or lightweight enough to provide high user comfort and efficiency, as they are limited by the size of the bearing unit and planet wheel, leading to friction losses and reduced durability.
Innovation Solution
A hand-held power tool transmission unit with a planetary gear stage featuring a roller bearing or needle bearing design, where the bearing unit is integrated with the planetary carrier and planet wheel, allowing for a compact and efficient gear system with a robust and precise transmission mechanism, independent of the planet wheel's diameter, and enabling a high transmission ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the bearing unit diameter is determined based on the planet wheel diameter in conventional designs, then the structure is simpler to design, but the transmission unit becomes larger and heavier, reducing user comfort
Solution Approach 1:
The patent changes the determining parameter for bearing unit diameter from planet wheel diameter to sun gear diameter. This parameter substitution allows the bearing unit to be sized based on the actual load requirements rather than the planet wheel size, resulting in a more compact and lighter transmission unit while maintaining structural integrity and performance
2Loss of energy
If conventional bearing units are used, then the design is easier to manufacture, but friction losses increase and efficiency decreases
Solution Approach 1:
The patent applies different quality requirements to different parts of the bearing unit. The bearing unit is designed with specific local characteristics including hardened running surfaces, optimized roller arrangements, and precision-machined contact areas. This localized quality enhancement reduces friction losses in critical areas while maintaining manufacturability through standardized bearing components
3Volume of moving object
If the bearing unit and planet wheel are designed independently, then manufacturing flexibility is improved, but the transmission unit size increases and compactness is reduced
Solution Approach 1:
The patent merges the bearing unit design with the planetary carrier structure. The bearing unit is integrated into the carrier assembly with optimized spatial arrangement, allowing the planet gears to rotate on their axes while the carrier rotates around the sun gear. This integration achieves compact packaging of the transmission unit while maintaining manufacturing flexibility through modular assembly of the planet gears, carrier, and bearing components
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 results in a compact, lightweight, and efficient hand-held power tool transmission unit with minimized friction losses, enhanced durability, and improved user comfort, providing a high level of operating convenience and efficiency.
Implementation Method 1
the at least one bearing unit is designed as a roller bearing... a particularly low-friction bearing unit and a particularly efficient planetary gear stage can be provided
Data Source
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AI summary
The invention relates to a hand-held machine tool gear unit having at least one planetary gear stage (12a, 14a, 16a), which comprises at least one planetary carrier (18a, 20a, 22a; 18b; 18c; 18d), at least one planet gear (24a-36a; 24b, 26b, 28b; 24c, 26c, 28c; 24d, 26d, 28d) mounted so as to rotate relative to said planetary carrier (18a, 20a, 22a; 18b; 18c; 18d), and at least one bearing unit (38a-46a; 38b, 40b, 42b; 38c; 38d) provided to mount said planet gear (24a-36a; 24b, 26b, 28b; 24c, 26c, 28c; 24d, 26d, 28d) such that it rotates relative to the planetary carrier (18a, 20a, 22a; 18b; 18c; 18d). According to the invention, the planet gear (24a-36a; 24b, 26b, 28b; 24c, 26c, 28c; 24d, 26d, 28d) comprises a bolt (48a-56a; 48b, 50b, 52b; 48c, 48d) which the bearing unit (38a-46a; 38b, 40b, 42b; 38c; 38d) mounts such that it can rotate in said planetary carrier (18a, 20a, 22a; 18b; 18c; 18d).