Robot Wrist Brake Layout for Compact Arm Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The braking device in existing robots protrudes in the axial direction from the rotary electric machine body, hindering the downsizing of the arm.
Innovation Solution
A robot design with a first arm and a second arm rotatably coupled, featuring a first motor with a first gear and a first brake device housed in the first arm, where the brake device faces the motor perpendicularly, and includes a third gear that rotates in conjunction with the first gear at a position separated from a second gear, with a gap between them, allowing for parallel and offset axial centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the braking device protrudes in the axial direction from the rotary electric machine body, then the braking function is achieved, but the arm size increases
Solution Approach 1:
The brake device is repositioned from an axial protrusion to a lateral arrangement. The brake shoe is positioned to engage the gear tooth surface radially, and the brake arm extends perpendicular to the motor axis, transforming the braking mechanism from an axial to a radial/lateral configuration. This dimensional change allows the brake to function without increasing the motor's axial length.
Solution Approach 2:
The brake device components are nested within the existing motor housing structure. The brake shoe is positioned inside the motor housing to engage the gear teeth, and the brake arm is arranged within the available lateral space. This nesting approach integrates the braking function into the existing motor envelope without requiring additional axial space.
2Device complexity
If the third gear is positioned close to the second gear, then the structure is compact, but gear wear increases due to potential contact
Solution Approach 1:
A gap is intentionally maintained between the third gear (brake gear) and the second gear (decelerator gear). This gap acts as a protective intermediary space that prevents direct contact and wear between the gears while the brake is engaged. The gap ensures that the brake shoe engages only the intended gear tooth surface without causing detrimental interference with adjacent gears.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Object To downsize an arm. Solution to Problem A robot (1) includes a wrist portion (15) and a flange portion (17). The robot (1) includes a motor (23) housed in the wrist portion (15) and including a first gear (35) that rotates around a motor axial center (AxM1). The robot (1) includes a decelerator (25) that decelerates rotation of a second gear (39) and transmits the decelerated rotation to an output shaft (43), the decelerator (25) including the second gear (39) that rotates, in conjunction with rotation of the first gear (35), around a decelerator axial center (AxR1) parallel to the motor axial center (AxM1) and offset from the motor axial center (AxM1), and the output shaft (43) coupled to the flange portion (17). The robot (1) includes a brake device (27) that brakes the rotation of the first gear (35), the brake device (27) being housed in the wrist portion (15) to face the motor (23) in a direction perpendicular to the motor axial center (AxM1), and including a third gear (51) that rotates around a brake axial center (AxB1) parallel to the motor axial center (AxM1) and the decelerator axial center (AxR1) and offset from each of the motor axial center (AxM1) and the decelerator axial center (AxR1), and rotates in conjunction with the first gear (35) at a position separated from the second gear (39).