Compact Rotation Actuator With Integrated Thrust Bearing Seal
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Solution Overview
Problem
Existing rotation actuators with flat structures face challenges in minimizing the center axis dimension due to the need for multiple bearings and lack of a compact seal mechanism to prevent grease outflow.
Innovation Solution
A rotation actuator design featuring an inner-rotor-type motor with a reduction gear mechanism, utilizing a planetary gear system and a sliding bearing that functions as both a thrust support and seal to reduce the number of bearings and prevent grease leakage, thereby minimizing the center axis dimension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple bearings are used to support the rotating shaft on the motor side, then the rotating shaft is adequately supported, but the center axis dimension of the motor portion increases
Solution Approach 1:
The patent combines the functions of multiple bearings into a single bearing structure. The first bearing simultaneously provides radial support and thrust support for the rotating shaft, eliminating the need for separate thrust bearings and reducing the center axis dimension while maintaining adequate support reliability.
Solution Approach 2:
The first bearing is designed as a multi-functional component that performs both radial support and thrust support functions. This universal bearing structure reduces the total number of bearings needed and minimizes the center axis dimension of the motor portion while ensuring reliable shaft support.
2Reliability
If multiple thrust bearings are disposed to receive thrust on the rotation output member, then thrust is adequately supported, but the device becomes less compact in the center axis direction
Solution Approach 1:
The patent merges the thrust support function into the existing bearing structures. The first bearing on the rotating shaft and the second bearing on the rotation output member both provide thrust support capabilities, eliminating the need for additional dedicated thrust bearings and achieving a more compact center axis dimension.
Solution Approach 2:
The bearings in this invention are designed as universal components that simultaneously handle radial loads and thrust loads. This multi-functionality allows adequate thrust support while maintaining a compact device structure with reduced center axis dimension.
3Reliability
If a seal mechanism is incorporated to prevent grease outflow, then grease retention is improved, but the device becomes more complex and larger
Solution Approach 1:
The patent integrates the seal function directly into the bearing structures. The bearing assemblies incorporate sealing capabilities as an inherent feature, combining the support and sealing functions into unified components. This reduces device complexity and avoids adding separate seal mechanisms that would increase the overall size.
Solution Approach 2:
The bearing structures are designed as multi-functional components that simultaneously provide mechanical support and sealing functions. This universal design prevents grease outflow while maintaining a simple and compact device structure without requiring additional dedicated seal mechanisms.
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
The design achieves a more compact rotation actuator with reduced center-axis dimensions and effective grease retention, enhancing the actuator's flattening and operational efficiency.
Implementation Method 1
a first bearing mounted between the first fixed member and the rotating shaft, the first bearing rotatably supporting the rotating shaft on the first fixed member
Implementation Method 2
a second bearing mounted between the second fixed member and the leading-end part of the rotating shaft, the second bearing rotatably supporting the rotating shaft on the second fixed member
Implementation Method 3
a third bearing mounted between the second fixed member and the rotation output member, the third bearing rotatably supporting the rotation output member on the second fixed member
Implementation Method 4
a reduction gear mechanism incorporated between the first fixed member and the second fixed member, the reduction gear mechanism reducing a rotation of the rotating shaft and transmitting a reduced rotation to the rotation output member
Data Source
Figure 1(a)~1(c)
Figure 2
AI summary
A rotation actuator (1) is equipped with a motor (2) and a reduction gear (3) disposed adjacent to each other. Both shaft end portions of a rotating shaft (5), which passes through the center of the motor (2) and reducer (3), are rotatably supported through first and second rolling bearings (14,15) by first and second fixed discs (11,12) that are mutually fastened and fixed. A rotation output plate (4) is supported through a third rolling bearing (18) in the outer peripheral surface of the second fixed disc (12). A sliding ring (19) is mounted between the rotation output plate (4) and the first fixed disc (11). The sliding ring (19) functions as a thrust bearing for the rotation output plate (4) and also functions as a sealing mechanism for preventing grease from flowing from the reducer gear (3) to the outside. A flat rotation actuator can be achieved.