Rotary Joint Shielding for Accurate Angle Measurement
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Solution Overview
Problem
Existing rotary joints face accuracy issues in measuring rotation angles due to adherence of foreign substances to sensors, which are exposed to the oil passage.
Innovation Solution
A rotary joint design featuring a shield member and a magnet system, where the shield member protects the angle measurement unit from foreign substances, and the magnet allows for accurate angle measurement using a magnetic sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor is positioned to face the oil passage for rotation angle detection, then the rotation angle can be measured, but foreign substances adhering to the sensor reduce measurement accuracy
Solution Approach 1:
A shield member is introduced as an intermediary component between the rod and the angle measurement unit. This shield member includes a through-hole that allows the rod to pass through while preventing foreign substances in the oil passage from directly contacting the angle measurement unit, thus protecting the sensor from contamination while still enabling rotation angle detection
Solution Approach 2:
The angle measurement unit is divided into separate components: a rod that rotates with the shaft, a shield member with a through-hole that protects the sensor, and the angle measurement unit itself that remains stationary or rotates differently. This segmentation allows the rod to be exposed to the oil passage for rotation while the sensor remains protected
2Measurement precision
If a shield member is introduced to protect the angle measurement unit, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The shield member serves multiple functions simultaneously: it acts as a protective barrier against foreign substances, provides structural support for the angle measurement unit, and includes a through-hole that allows the rod to pass through while maintaining rotational capability. This multi-functionality reduces the need for additional separate components
Solution Approach 2:
The shield member combines the protective function with the structural housing function, integrating what could have been separate components into a single unified structure that simplifies assembly and reduces overall device complexity
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
Enables high-accuracy rotation angle measurement by preventing foreign substances from adhering to the angle measurement unit and magnet, thereby enhancing measurement precision.
Implementation Method 1
a magnet provided between the other end of the rod and an inner bottom surface of the shield member, in which the angle measurement unit measures a change in magnetic field generated from the magnet with a magnetic sensor provided on a surface facing an outer bottom surface of the shield member
Data Source
AI summary
A rotary joint capable of measuring a rotation angle with high accuracy includes: a flange; a rotor whose one end is connected with the flange and has a tubular shape; a shaft whose outer periphery is connected with an inner periphery of the rotor so that the shaft is rotatable about a central axis of the rotor as a rotation axis; and a rod whose one end is connected with the flange and is provided in an opening to extend from one end side of the shaft along the central axis; an angle measurement unit connected with the opening to extend from another end side of the shaft to another end of the rod and measures a rotation angle between the rod and the shaft with the central axis as the rotation axis; and a shield member formed in a cup shape.