Crank Angle Detection Device With Metal Pulsar Ring
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Solution Overview
Problem
Conventional crank angle detection devices face challenges in improving detection accuracy due to the difficulty in increasing the number of convex portions formed integrally with the outer circumferential face of the ACG rotor.
Innovation Solution
A crank angle detection device featuring a metal-plate-made pulsar ring with a larger outer diameter than the ACG rotor, where the convex portions are formed on the pulsar ring and bent towards the ACG rotor, allowing for easier formation and increased number of detection features, enhancing detection accuracy with a magnetic sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If convex portions are formed integrally with the outer circumferential face of the ACG rotor, then the structural integrity is maintained, but the number of convex portions cannot be increased to improve detection accuracy
Solution Approach 1:
The invention separates the pulsar ring from the ACG rotor, making them independent components. The pulsar ring with convex portions can be manufactured separately and then attached to the ACG rotor. This segmentation allows the convex portions to be increased in number without compromising the structural integrity of the ACG rotor, thereby improving crank angle detection accuracy while maintaining ease of manufacture.
2Measurement precision
If the outer diameter of the pulsar ring is increased to allow more convex portions, then detection accuracy improves, but the device length in axial direction increases
Solution Approach 1:
The invention utilizes the radial dimension by increasing the outer diameter of the pulsar ring to accommodate more convex portions for improved detection accuracy. The pulsar ring is designed with a larger outer diameter than the ACG rotor, allowing the convex portions to be arranged in a circumferential pattern that enhances detection precision without extending the axial length of the overall device.
3Measurement precision
If convex portions are bent toward the axial direction to face the magnetic sensor, then detection accuracy increases, but the axial length increases
Solution Approach 1:
The invention optimizes the bending angle and orientation of the convex portions to face the magnetic sensor positioned at the outer circumference of the pulsar ring. By adjusting the parameter of convex portion orientation (bending toward the radial direction to face the sensor), detection accuracy is maximized while minimizing the axial length extension.
4Ease of manufacture
If the pulsar ring is made separately from the ACG rotor, then the convex portions can be easily formed with pressing, but the device complexity increases
Solution Approach 1:
The invention divides the system into two main segments: the ACG rotor and the pulsar ring. The pulsar ring is manufactured separately with convex portions formed by pressing, which is easier than forming integral convex portions on the ACG rotor. The pulsar ring is then attached to the ACG rotor, creating a modular assembly that improves manufacturability while adding only one additional component to the system.
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 solution significantly improves crank angle detection accuracy by allowing for more convex portions to be easily formed and detected, reducing axial length, and effectively utilizing space in the crank case, while minimizing detection errors.
Implementation Method 1
a magnetic sensor arranged at an outer circumference of the pulsar ring and configured to detect the detected portion
Data Source
AI summary
Provided is a crank angle detection device that includes an ACG rotor supported by an end of a crank shaft and configured to rotate integrally with the crank shaft, a metal-plate-made pulsar ring including a ring-shaped plate portion and a detected portion that includes a plurality of convex portions formed at an outer circumference of the ring-shaped plate portion, and being configured to rotate integrally with the ACG rotor with the ring-shaped plate portion fixed to the ACG rotor, and a magnetic sensor arranged at an outer circumference of the pulsar ring and configured to detect the detected portion. Such a crank angle detection device is capable of detecting a crank angle with high accuracy.