Dual-Case Speed Reducer Layout for Compact Bucket Torque Transmission
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Solution Overview
Problem
Existing electric-powered construction machines face issues with reduced efficiency and increased risk of damage due to the arrangement of electric motors and speed reducers, either within the bucket or protruding from the arm, which affects torque transmission and size constraints.
Innovation Solution
A speed reducer design with a carrier holding two cases that rotate relative to it, each connected to a motor, allowing separate torque transmission to multiple members while minimizing size and protecting components from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electric motor and speed reducer are arranged inside the bucket, then the bucket volume is reduced, but the excavation efficiency decreases and the risk of damage increases
Solution Approach 1:
The speed reducer is extracted from the bucket and relocated to the arm structure. The patent describes that the speed reducer is mounted on the arm at a position away from the bucket, allowing the bucket to maintain its full volume and excavation capacity while the speed reducer performs its torque transmission function from a protected location.
2Volume of moving object
If the electric motor and speed reducer are located outside the bucket, then the bucket volume is maintained, but the components are more prone to contact with ground or structure
Solution Approach 1:
The arm structure serves as an intermediary between the bucket and the speed reducer. The speed reducer is mounted on the arm at a strategically chosen position that is away from the ground and structural contacts, using the arm as a protective intermediary structure to shield the components while maintaining functional connectivity to the bucket.
3Area of stationary object
If the electric motor for the arm and electric motor for the bucket are arranged adjacent to each other, then space is utilized, but a large region is occupied and components protrude significantly
Solution Approach 1:
The patent utilizes the axial dimension of the carrier along the rotation axis to position the first and second cases at different locations. Instead of arranging components side-by-side in the radial direction (which would cause protrusion), the cases are distributed along the axial direction, reducing the overall radial footprint and preventing significant protrusion from the arm.
4Volume of moving object
If the motor and speed reducer have a smaller size, then the overall size is reduced, but the desired torque cannot be transmitted
Solution Approach 1:
The first case and second case are nested within the same carrier structure, with both cases positioned within the axial length of the carrier. This nested arrangement allows the speed reducer to accommodate multiple gear reductions and torque transmission paths within a compact volume, maintaining torque transmission capability while reducing the overall size of the speed reducer assembly.
Data Source
AI summary
A speed reducer according to an embodiment includes: a carrier; a first case encircling an outer circumferential surface of the carrier between two end surfaces of the carrier, the first case being held by the carrier so as to rotate relative to the carrier; a second case encircling the outer circumferential surface of the carrier and held by the carrier at a different position than the first case so as to rotate relative to the carrier; a first reduction portion including a first input portion held by the carrier and configured to receive rotation input from a first side toward which one of the two end surfaces of the carrier faces; and a second reduction portion including a second input portion held by the carrier and configured to receive rotation input from a second side toward which another of the two end surfaces of the carrier faces.