Injection-Molded Magnetic Target for Precise Shaft Position Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brake systems with ESP and ABS functionality face challenges in accurately detecting the rotational position of motor shafts due to the complexity of attaching permanent magnets, which requires precise positioning and adhesive or press-fit methods, leading to increased manufacturing and assembly steps, tolerance chains, and component eccentricities.
Innovation Solution
A magnetic measuring device with a plastic-bonded permanent magnet molded directly onto the body, eliminating the need for separate cups and adhesives, allowing for a more accurate and stable attachment, reduced tolerance chains, and the use of cheaper magnetic materials, while enabling non-contact detection of rotational movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent magnet is attached to the motor shaft using a cup with adhesive or press-fit methods, then the permanent magnet can be secured to the shaft, but the manufacturing and assembly process becomes complex with increased manufacturing steps, tolerance chains, and component eccentricities
Solution Approach 1:
The patent merges the permanent magnet attachment function directly into the motor shaft by forming a recess in the shaft that receives the permanent magnet. This eliminates the separate cup component and its associated adhesive or press-fit attachment methods, thereby reducing assembly complexity while maintaining reliable magnet attachment.
2Manufacturing precision
If a cup is used to accommodate the permanent magnet and secure it to the motor shaft, then the permanent magnet can be positioned with high precision, but the number of components and assembly steps increases
Solution Approach 1:
The positioning function previously provided by the cup is now integrated directly into the motor shaft through a recess formed in the shaft. This eliminates the need for a separate cup component while maintaining precise permanent magnet positioning, thereby simplifying manufacturing without sacrificing positioning accuracy.
3Object-generated harmful factors
If a cup with base is used as magnetic insulation between the permanent magnet and the motor shaft, then leakage of the effective magnetic field into the motor shaft is reduced, but the device complexity and component count increase
Solution Approach 1:
The magnetic insulation function is integrated directly into the motor shaft by forming a non-magnetic recess in the shaft that receives the permanent magnet. This eliminates the need for a separate cup with base to provide magnetic insulation, thereby reducing component count while maintaining effective magnetic field containment.
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 approach simplifies the assembly process, improves positioning accuracy, reduces component costs, and enhances the design flexibility for subsequent assembly processes, enabling efficient detection of rotational or translational movements in motor-pump units and other applications.
Implementation Method 1
A plastic-bonded permanent magnetic material is molded onto the body as an axial extension and forms a free end of the body as a permanent magnet
Implementation Method 2
a permanent magnet that is connected to the body in a rotationally fixed manner and moves with the body. A plastic-bonded permanent magnetic material is molded onto the body as an axial extension and forms a free end of the body as a permanent magnet
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a sensor (16) for a magnetic measuring device (20) for detecting a rotational or translational movement of a body (10), said sensor comprising a permanent magnet (16A) which is connected to the body (10) for conjoint rotation and which moves with the body (10). The invention also relates to a method for fastening such a sensor (16) to a body (10), and to a magnetic measuring device (20) for contactlessly detecting a rotational movement of a body (10) using such a sensor (16). Plastic-bonded permanent magnet material is injection-moulded onto the body (10), acting as an extension thereof, and forms a free end of the body (10) acting as a permanent magnet (16A).