Resin Upper Case Rotary Actuator with Metal Fastening
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Solution Overview
Problem
Conventional rotary actuators with metal upper cases face issues of increased mass, reduced fuel efficiency, and compromised sealing due to corrosion, leading to concerns about weight, vibration resistance, and size.
Innovation Solution
A rotary actuator design featuring a resin-made upper case, a metal lower case, and a metal case fastening member that fixes the controller board without the need for an insert nut, reducing weight and size while ensuring vibration resistance and improved sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal upper case is used to house the controller, then the structural strength is improved, but the mass increases and fuel efficiency decreases
Solution Approach 1:
The patent applies composite materials by combining resin for the upper case (to reduce weight) with metal fastening members (to provide necessary strength). This allows the controller housing to achieve both lightweight properties and structural integrity through material composition rather than using solid metal throughout.
Solution Approach 2:
The patent applies local quality by using metal only where structurally necessary - specifically in the fastening members that secure the controller board - while using resin for the main upper case body. This localized application of metal provides strength precisely where needed without unnecessarily increasing overall mass.
2Stability of the object's composition
If a metal upper case is used, then the structural integrity is maintained, but corrosion resistance deteriorates compromising sealing
Solution Approach 1:
The patent uses composite materials combining resin and metal components. The resin upper case provides inherent corrosion resistance to maintain sealing integrity, while metal fastening members provide structural support. This composite approach ensures both structural integrity and reliable sealing without the corrosion problems of solid metal construction.
Solution Approach 2:
The patent introduces resin as an intermediary material between the metal fastening members and the external environment. The resin upper case acts as a protective barrier that prevents direct exposure of metal components to corrosive elements, thereby maintaining both structural integrity and sealing reliability.
3Strength
If an insert nut is used to fix the controller board to the resin upper case, then the fixing strength is improved, but the device complexity and size increase
Solution Approach 1:
The patent merges the fastening function directly into the metal case fastening member itself. The board fixing member integrates the securing mechanism, eliminating the need for separate insert nuts. This consolidation reduces the number of components and simplifies the overall structure while maintaining fixing strength.
Solution Approach 2:
The metal case fastening member serves multiple functions: it fastens the upper case to the lower case and simultaneously provides the fixing structure for the controller board. This multi-functionality eliminates the need for separate insert nuts, reducing device complexity while maintaining necessary fixing strength.
4Weight of moving object
If a resin upper case is used, then the weight is reduced and fuel efficiency is improved, but the vibration resistance may be compromised
Solution Approach 1:
The patent uses composite materials where the resin upper case provides lightweight properties while metal fastening members provide vibration resistance. The combination allows the overall structure to achieve both reduced weight and adequate vibration resistance that would be difficult to obtain with resin alone.
Solution Approach 2:
The patent applies local quality by using metal components specifically at critical fastening points where vibration resistance is most needed, while maintaining resin construction for the main case body. This localized reinforcement provides vibration resistance precisely where required without significantly increasing overall weight.
Data Source
AI summary
A rotary actuator is used in a shift-by-wire system for a vehicle. The actuator includes a motor, a controller, an upper case, a lower case, a case fastening member, and a board fixing member. The controller controls the motor. The upper case is made from resin and houses the controller. The lower case houses the motor together with the upper case. The case fastening member is made from metal and fastens the upper case and the lower case to each other. The board fixing member fixes a board of the controller to the case fastening member.