Hollow Speed Reducer Axial Length Reduction
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Solution Overview
Problem
Existing hollow speed reducers for robots result in large-sized turning structures due to the size of the motor, making it difficult to downsize the axial length, and require additional speed reduction mechanisms to achieve high output, which complicates the structure further.
Innovation Solution
A hollow speed reducer with a center gear coaxial to the hollow hole, where small gears from multiple motors mesh with the center gear, allowing for equal distribution around the rotation axis to shorten the axial length and facilitate a high speed reduction ratio using planetary or wave gear mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single large motor is used to drive the hollow speed reducer, then the speed reduction ratio can be increased, but the axial length of the turning structure becomes large
Solution Approach 1:
The single large motor is segmented into multiple small motors arranged around the rotation axis. Each small motor drives a corresponding small gear that meshes with the center gear. This segmentation allows the axial length to be reduced while maintaining the required speed reduction ratio through the combined effect of multiple drive sources.
Solution Approach 2:
The drive configuration transitions from a single axial drive to a radial distribution of multiple drive sources around the rotation axis. By utilizing the circumferential dimension, the patent achieves high speed reduction ratio without increasing the axial length, as the multiple small motors are arranged in the radial plane rather than extending axially.
2Device complexity
If a single large motor is used, then the structure is simple, but the turning structure becomes large-sized
Solution Approach 1:
The single large motor is divided into multiple small motors, and the single large gear is segmented into multiple small gears. This segmentation allows compact arrangement around the rotation axis, reducing the overall volume of the turning structure while distributing the mechanical load across multiple smaller components.
Solution Approach 2:
The multiple small motors and small gears are arranged concentrically around the center gear, with each component nested within the radial space of the hollow speed reducer. This nested arrangement maximizes space utilization and minimizes the external dimensions of the turning structure.
3Power
If additional speed reducing mechanisms are attached to increase speed reduction ratio, then the output can be increased, but the structure becomes more complex
Solution Approach 1:
Multiple small motors and small gears are merged into a single integrated drive system that directly meshes with the center gear. This combining of multiple drive sources into one unified mechanism achieves high output without requiring separate speed reducing mechanisms, thereby avoiding additional structural complexity.
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 enables a compact turning structure, allows for continuous operation even if one motor fails, simplifies maintenance by eliminating the need for mechanical locks, and facilitates easier original point return operations.
Implementation Method 1
a planetary gear apparatus comprising a crankshaft (11), a pinion (12) formed with outer teeth at an outer periphery thereof, fitted to a crank portion (11a) of the crankshaft and eccentrically moved, and a case (13) an inner peripheral face of which is formed with inner teeth brought in mesh with the outer teeth of the pinion (12)
Implementation Method 2
the hollow speed reducer may be a wave gear speed reducer comprising a wave generator, a flex-spline and a circular spline
Data Source
Figure 1A~1B
Figure 1C
Figure 2A
AI summary
There is provided a speed reducer capable of shortening a length in an axial direction of a turning structure by arranging a plurality of small-sized motors. A hollow speed reducer 10 is a planetary gear apparatus comprising a crankshaft 11, a pinion 12 formed with outer teeth at an outer periphery thereof, fitted to a crank portion of the crank shaft 11 and eccentrically moved, and a case 13 an inner peripheral face of which is formed with inner teeth brought in mesh with the outer teeth of the pinion 12, in which an inner portion of the hollow speed reducer 10 is formed with a hollow hole, a center gear for an input of the hollow speed reducer 10 is provided at a position of the hollow hole, and small gears provided at output shafts of a plurality of motors are simultaneously brought in mesh with the center gear.