Welded Housing Positioning Device Axial Play Control
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Solution Overview
Problem
Existing positioning devices face challenges in maintaining a precise axial play to prevent output wheel jamming due to heat expansion and temperature differences, which requires tight manufacturing tolerances and limited temperature ranges, increasing costs and reducing operational flexibility.
Innovation Solution
A positioning device with a housing comprising two welded parts, featuring integrally formed bearing points and a gearing system with an output shaft and wheel, where the axial play is predetermined by adjusting the outer and inner distances between bearing points and surfaces, allowing the output wheel to shift and interact with both bearing surfaces, ensuring the Hall-sensor can detect rotary position without jamming, and using methods like laser or ultrasound welding to achieve this configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manufacturing tolerances of individual constituent parts are reduced to achieve precise axial play, then the axial play precision is improved, but the manufacturing costs substantially increase
Solution Approach 1:
The housing is divided into two separate parts (first housing part and second housing part) that are welded together. The bearing is split between these two housing parts, with each housing part containing one bearing element. This segmentation allows the axial play to be adjusted by controlling the distance between the two housing parts through welding, rather than requiring tight tolerances on all individual components.
Solution Approach 2:
The invention changes the approach from controlling axial play through component dimensions to controlling it through the distance between housing parts. By making the housing parts adjustable relative to each other during welding, the axial play parameter can be precisely controlled without requiring tight manufacturing tolerances on the individual housing parts or bearing components.
2Reliability
If the axial play is increased to prevent jamming of the output wheel, then the reliability is improved, but the sensing precision of the Hall-sensor deteriorates
Solution Approach 1:
The invention introduces a dynamic, adjustable axial play that can be precisely controlled within a narrow range. By allowing adjustment of the distance between the two housing parts during welding, the system achieves an optimal balance between preventing jamming (requiring sufficient axial play) and maintaining sensor precision (requiring limited axial play variation).
Solution Approach 2:
The axial play parameter is controlled by adjusting the distance between the two housing parts rather than by fixing component dimensions. This allows for precise control of the axial play within a narrow tolerance range (e.g., 0.02-0.05mm), which is sufficient to prevent jamming while maintaining Hall-sensor detection accuracy.
3Device complexity
If the operating temperature range is restricted to maintain axial play within tolerance, then the manufacturing complexity is reduced, but the adaptability deteriorates
Solution Approach 1:
By segmenting the housing into two adjustable parts, the invention decouples the thermal expansion issues from the axial play control. The welding joint between the two housing parts can accommodate thermal expansion and contraction, allowing the positioning device to operate across a wider temperature range without requiring complex compensation mechanisms or restricting the operating temperature range.
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 solution allows for a cost-effective production of positioning devices with reduced manufacturing tolerances and expanded temperature ranges, ensuring reliable operation by maintaining the axial play within a close tolerance range and preventing output wheel jamming.
Implementation Method 1
a permanent magnet and a Hall-sensor are usually fixed to the end face of the output shaft and to the housing respectively. Here, the permanent magnet serves as transducer for the Hall-sensor that can sense the rotary position of the output shaft at a sensing distance.
Implementation Method 2
a positioning device for mechanically actuating a component comprises a housing with a first housing part and with a second housing part, which are welded to one another via an axial welded connection
Data Source
AI summary
A positioning device for mechanically actuating a component may include a housing with first and second housing parts welded to one another via an axial welded connection. The first and second housing parts may have integrally formed first and second bearing points, respectively, of a bearing within the housing. The positioning device may also include a gearing fixed in the housing, the gearing having an output shaft penetrating the second housing part and being drive-connectable with the component outside the housing, and an output wheel non-rotationally fixed on the output shaft and rotatably mounted in the bearing. The positioning device may further include a rotary position detector with a permanent magnet and a Hall sensor, the permanent magnet being arranged on a gear wheel of the output shaft or on the output shaft at an end face of the output shaft, and the Hall sensor being arranged on the first housing part. End faces of the first and second bearing points may interact axially with first and second bearing surfaces, respectively, of the output wheel located opposite each other. The bearing may have a predetermined axial play defined by a difference between an outer axial distance between the first and second bearing points and an inner axial distance between the first and second bearing surfaces.