Force Sensor Stopper Shim Clearance Adjustment
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Solution Overview
Problem
High-sensitivity six-axis force sensors face challenges in accurately managing the distance between the force-receiving body and stopper due to extremely small displacement, which can lead to damage from excessive external forces.
Innovation Solution
The implementation of a force sensor design with a stopper mechanism that includes a first side surface and a second side surface with specific diameters, where a shim is used to adjust and accurately set the clearance between the stopper and the force-receiving body, ensuring precise protection and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stopper mechanism is provided to protect the diaphragm part from excessive external force, then the reliability of the force sensor is improved, but the device complexity increases due to the need to manage the distance between the force-receiving body and stopper with extremely high accuracy
Solution Approach 1:
A shim is introduced as an intermediary component between the stopper and the force-receiving body. The shim has a predetermined thickness that sets the clearance distance, allowing accurate control of the stopper clearance without requiring direct precision management between the stopper and force-receiving body. This mediator component simplifies the overall device complexity while maintaining reliable protection.
2Measurement precision
If the distance between the force-receiving body and stopper is managed with extremely high accuracy, then the sensitivity of the force sensor is improved, but the manufacturing precision requirements increase significantly
Solution Approach 1:
The shim is pre-manufactured with a predetermined thickness that corresponds to the desired clearance distance. By preparing the shim in advance with the correct dimensional specification, the complex task of managing the distance between the force-receiving body and stopper with extremely high accuracy during final assembly is avoided. The preliminary preparation of the shim transfers the precision requirement to a separate manufacturing step.
Solution Approach 2:
The shim acts as a mediator that encapsulates the precision requirement within its own dimensional specification. Instead of requiring the assembly process to achieve extremely high distance management accuracy, the shim's predetermined thickness serves as a built-in precision element that simplifies the overall manufacturing process while maintaining the required sensitivity.
3Duration of action of stationary object
If the clearance between the stopper and force-receiving body is set accurately, then the durability of the strain body is improved by preventing excessive deformation, but the ease of manufacture decreases due to the need for precise adjustment
Solution Approach 1:
The shim is pre-prepared with the correct thickness before assembly. This preliminary action ensures that when the shim is installed between the stopper and the force-receiving body, the clearance is automatically set to the predetermined accurate value. This eliminates the need for complex post-assembly adjustment procedures, thereby improving ease of manufacture while ensuring the strain body is protected from excessive deformation.
Solution Approach 2:
The shim serves as an intermediary adjustment element that simplifies the manufacturing process. Instead of requiring precise direct adjustment between the stopper and force-receiving body, the shim provides a simple insertion-based adjustment mechanism. This mediator component makes the assembly process easier while ensuring the clearance is set accurately to protect the strain body.
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 allows for accurate management of the stopper clearance, preventing excessive deformation and enhancing the sensor's sensitivity and durability by effectively limiting the displacement of the force-receiving body, thus protecting the strain body from damage.
Implementation Method 1
external force to be applied to a force-receiving body serving as a movable part is transmitted to, for example, a diaphragm part serving as a strain body, and deformation of the diaphragm part is converted into an electrical signal to thereby be detected
Data Source
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AI summary
In a force sensor, a cylindrical movable body 12 can be moved with respect to a cylindrical main body 11. A strain body 16 is fixed to the main body and the movable body, and can be deformed in accordance with the movement of the movable body. Strain sensors 26 are provided on the strain body. At least three circular openings 13 are provided in the circumferential surface of the movable body 12 at equal intervals. Stoppers 14 are respectively arranged inside the openings 13, and each of which includes a first side surface 14a having a first outer diameter smaller than an inner diameter of the opening 13, and a second side surface 14b having a second outer diameter smaller than the first outer diameter. Fixing members 15 fix the stoppers 14 to the main body 11.