Rotation Angle Detector Creepage Barrier
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Solution Overview
Problem
Conventional rotation angle detecting devices have a high assembly and parts cost due to a large number of components, and there is a risk of the filling member entering the wrong accommodating portion and hindering the rotation of the magnet or rotation member during the molding process.
Innovation Solution
A rotation angle detecting device with a creepage distance extending portion on the cylindrical metal member, which is formed integrally with the housing, prevents the filling member from entering the first accommodating portion by increasing the distance between the metal member and the housing, thus ensuring proper accommodation of the magnet and magneto-electric conversion element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the housing is formed integrally with the metal member through insertion molding, then the number of parts is reduced and assembly cost is lowered, but the filling member may enter the first accommodating portion and hinder rotation of the magnet or rotation member
Solution Approach 1:
The patent divides the housing into two separate accommodating portions: a first accommodating portion for the magnet/rotation member and a second accommodating portion for the magneto-electric conversion element. This segmentation prevents the filling member from entering the first accommodating portion while maintaining the integral formation of the housing and metal member through insertion molding, thus resolving the contradiction between part reduction and rotation functionality.
Solution Approach 2:
The patent introduces a partition wall as an intermediary structure between the first and second accommodating portions. This partition wall acts as a barrier that prevents the filling member from migrating from the second accommodating portion to the first accommodating portion, thereby protecting the rotation functionality while maintaining the cost benefits of integral housing formation.
2Reliability
If the filling member is used to hermetically seal the magneto-electric conversion element, then the protection of the conversion element is improved, but the filling member may be introduced between the metal member and housing to enter the first accommodating portion
Solution Approach 1:
The housing is segmented into two distinct accommodating portions separated by a partition wall. This segmentation ensures that the filling member, while performing its hermetic sealing function in the second accommodating portion, cannot migrate into the first accommodating portion, thus eliminating the harmful effect of filling member intrusion while maintaining hermetic sealing benefits.
3Manufacturing precision
If the second accommodating portion is filled with filling member to hold the magneto-electric conversion element, then the positioning and protection of the conversion element is improved, but the filling member may prevent accommodation of the magnet or hinder rotation
Solution Approach 1:
The patent employs segmentation by creating two separate accommodating portions within the housing. The second accommodating portion is filled with the filling member to achieve precise positioning and protection of the magneto-electric conversion element, while the partition wall prevents the filling member from entering the first accommodating portion, thereby ensuring that magnet accommodation and rotation operation are not hindered.
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 reduces the risk of assembly errors and costs by preventing the filling member from entering the wrong compartment, ensuring smooth rotation and reducing the overall cost of the device while maintaining the integrity of the components.
Implementation Method 1
a magneto-electric conversion element which is placed at the back of the rotation shaft and detects a change in the magnitude of a magnetic flux (the magnitude of a magnetic field) in association with the rotation operation of each of the magnets
Data Source
Figure 1
AI summary
Disclosed is a rotation angle detecting device wherein a filling member applied in a second housing section which houses an electromagnetic conversion element is prevented from entering a first housing section which houses a magnet. The rotation angle detecting device (1) is provided with: a rotating member (2); the magnet (3), which is fixed to the rotating member (2) and rotates with the rotation of the rotating member (2); a magnetism detecting package (4) that houses an electromagnetic conversion element (4a), which is disposed to face the magnet (3), and detects the intensity of the magnetic field of the magnet (3) by means of rotation of the magnet (3); a housing (5) having a first housing section (5b) that rotatably houses the rotating member (2), and a second housing section (5d) that houses the magnetism detecting package (4), with a partition (5f) as a reference; a filling member (10), with which the second housing section (5d) is filled such that the magnetism detection package (4) is hermetically housed and held; and a cylindrical metal member (11), which is provided in the first housing section (5b) such that the rotating member (2) is rotatably supported and a part (11a) of the metal member is exposed to the second housing section (5d). In the vicinity of a part (11a) of the metal member (11), said portion being exposed to the second housing section (5d), a creeping distance extending section (11b) that suppresses entry of the filling member (10) between the metal member (11) and the housing (5) is provided on a portion housed in the housing (5).