Compact Transmission Nested Gear Stage for Single Wheel Drive
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Solution Overview
Problem
Existing compact transmissions with a preliminary gear stage increase installation space and require additional effort when used with electric motors, as they need to operate at high speeds to match the power density of hydraulic motors, leading to increased complexity and risk of contamination.
Innovation Solution
A compact transmission design with a frame-fixed gearbox carrier and a preliminary gear stage within the central recess, featuring a radially mounted internally toothed ring gear, externally toothed gears, and a radial seal to prevent lubricant escape, along with a peripheral collar for axial support and countersunk screws for secure attachment, allowing for efficient torque transmission and lubrication at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a preliminary gear stage is added to match the power density of hydraulic motors when using electric motors, then the power density is improved, but the installation space and device complexity increase
Solution Approach 1:
The preliminary gear stage is nested within the central recess of the existing gearbox carrier, utilizing the empty space that would otherwise be unused. The preliminary stage sun gear, intermediate gears, and ring gear are arranged concentrically within this recess, allowing the preliminary gear stage to be housed without increasing the overall axial length of the transmission assembly.
Solution Approach 2:
Instead of adding the preliminary gear stage in the axial direction (which would increase installation space), the design utilizes the radial dimension by arranging the preliminary stage components within the central recess of the gearbox carrier. The preliminary stage ring gear is firmly inserted into the gearbox carrier, while the sun gear and intermediate gears are positioned radially within the available space.
2Power
If a preliminary gear stage is added to match the power density of hydraulic motors when using electric motors, then the power density is improved, but the device complexity and risk of contamination increase
Solution Approach 1:
The preliminary gear stage is integrated with the main gearbox by firmly inserting the preliminary stage ring gear into the gearbox carrier. This merging eliminates the need for separate housings and mounting interfaces, reducing the number of parts and assembly steps. The preliminary stage intermediate gears are positioned within the central recess and mesh with both the sun gear and ring gear, creating a compact unified structure.
Solution Approach 2:
The gearbox carrier serves multiple functions: it supports the main stage ring gear on its outer side, firmly holds the preliminary stage ring gear within its central recess, and provides structural support for the entire transmission assembly. This multi-functionality reduces the need for additional components and simplifies the overall device structure.
3Strength
If the preliminary stage ring gear is firmly inserted into the gearbox carrier, then the structural integrity is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The preliminary stage ring gear is designed to be firmly self-inserted into the gearbox carrier without requiring additional fastening elements or complex assembly procedures. The firm insertion creates a stable structural connection that maintains integrity while simplifying the manufacturing and assembly processes.
Data Source
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AI summary
The invention relates to a compact transmission, which in particular is provided for use within a single-wheel drive unit. The compact transmission has a gear carrier that is fixed to the frame, which has a continuous central recess, and a main transmission, comprising an internally toothed ring gear, which is rotatably mounted on the outside of the gear carrier, externally toothed gears arranged in front of the one of the end faces of the gear carrier and meshing with the ring gear, and an input sun shaft. The compact transmission further has a transmission pre-stage, which is arranged within the central recess of the transmission carrier, and a pre-stage input shaft having an externally toothed pre-stage sun wheel, a pre-stage ring gear, and at least one pre-stage intermediate gear, preferably a plurality of pre-stage intermediate gears, that mesh with both the pre-stage sun wheel and with the pre-stage ring gear. According to the invention, an additional carrier is fastened to the transmission carrier, by means of which the pre-stage intermediate gears are held captively in the central recess of the transmission carrier.