Robot Arm Gear-Decelerator Layout for Compact Elbow Assembly
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Solution Overview
Problem
The existing robot designs have a housing for the motor positioned offset to the outer side in the radial direction, increasing the distance between the decelerator's first axis and the motor's end portion, leading to an enlarged size of the robot arm.
Innovation Solution
A robot design where the motor is housed in a first arm, with a first gear rotating around a first axial center, a second gear rotating around a second axial center intersecting the first, and a decelerator that decelerates the input shaft's rotation and transmits it to an output shaft, with the second gear and input shaft rotating around the second axial center, allowing for a compact arm configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the housing that houses the second power transmission portion and supports the motor is attached at the position offset to the outer side in the radial direction with respect to the hollow hole of the decelerator, then the motor can be supported, but the distance between the first axis of the decelerator and the end portion of the motor is increased, leading to an increase in the size of the first member
Solution Approach 1:
The patent applies nesting by placing the motor (23) and its housing (29) inside the hollow hole (41) of the decelerator (27), and further nesting the second gear (37) and its housing (35) within the same hollow space. This nested arrangement allows multiple components to occupy the same spatial envelope, eliminating the need for offset positioning and reducing the overall robot arm size while maintaining proper motor support and power transmission functionality.
2Ease of operation
If the housing is detachably attached to the first member at a position offset to the outer side, then the power transmission mechanism can be engaged, but the robot arm requires more space for component arrangement
Solution Approach 1:
The patent utilizes the hollow hole (41) of the decelerator as a nesting space to accommodate the motor (23) and second gear (37) assemblies. By nesting these components within the existing decelerator structure rather than offsetting them externally, the patent achieves compact component arrangement that reduces robot arm length while maintaining detachable attachment capability for power transmission engagement.
3Power
If the motor is positioned on the opposite side to the first axis, then power transmission can be achieved, but the distance from the decelerator axis increases the overall component size
Solution Approach 1:
The patent nests the motor (23) and second gear (37) within the hollow hole (41) of the decelerator (27), allowing power transmission components to be arranged in a compact, concentrated manner. This nesting approach enables effective power transmission from the motor through the gears to the decelerator while minimizing the volume required for housing these components, as they share the same spatial envelope rather than being distributed across a larger volume.
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 design enables the downsizing of the robot arm by reducing the distance between the motor and decelerator axes, improving assemblability and reducing noise, while allowing for easier adjustment and assembly operations.
Implementation Method 1
a first gear (33) coupled to the rotation shaft (31) and configured to rotate around the first axial center (AxM), a second gear (37) configured to rotate, in conjunction with the first gear (33), around a second axial center (AxG) intersecting the first axial center (AxM)
Implementation Method 2
a decelerator (27) configured to decelerate rotation of an input shaft (47) and transmit the decelerated rotation to an output shaft (51)
Data Source
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AI summary
Object To provide a robot (1) and a method for manufacturing the robot (1) with which downsizing of an arm is possible. Solution to Problem A robot (1) includes a lower arm portion (9), an elbow portion (11) rotatably coupled to the lower arm portion (9), a motor (23) housed in the lower arm portion (9) and including a motor shaft (31) rotating around a motor axial center (AxM), a first gear 33 coupled to the motor shaft 31 and rotating around the motor axial center (AxM), a second gear (37) rotating, in conjunction with the first gear (33), around a gear axial center (AxG) intersecting the motor axial center (AxM), and a decelerator (27) configured to decelerate rotation of an input shaft (47) and transmit the decelerated rotation to an output shaft (51), the decelerator including the input shaft (47) configured to rotate, in conjunction with the second gear (37), around a decelerator axial center (AxR) coinciding with the gear axial center (AxG), and the output shaft (51) coupled to the elbow portion (11).