Rotary Encoder Torque Support for Thermal Expansion and Vibration
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Solution Overview
Problem
Existing fastening techniques for rotary encoders in electric motors suffer from concentricity errors, production tolerances, thermal expansion, and vibrations, leading to fatigue failures and consequential damage due to inadequate torsional rigidity and mechanical stress.
Innovation Solution
A fastening element with a ring and radially extending webs, featuring first and second recesses for threaded attachment, providing increased circumferential rigidity while allowing axial movement to compensate for thermal expansion and misalignment, manufactured from steel for robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fastening techniques are used to mount the encoder, then the encoder can be attached to the housing, but mechanical stresses increase leading to fatigue fractures
Solution Approach 1:
The fastening element is segmented into a ring component and multiple web components that extend radially outward. This segmentation allows each web to independently absorb and distribute mechanical stresses, preventing stress concentration at single attachment points and reducing the risk of fatigue fractures while maintaining reliable encoder mounting.
Solution Approach 2:
The web components are designed with flexible geometry that allows them to dynamically adapt to thermal expansion and misalignment forces. The webs can elastically deform to accommodate dimensional changes and position variations, thereby reducing mechanical stresses on the encoder mounting while maintaining reliable connection to the housing.
2Stability of the object's composition
If rigid connection is used to prevent encoder rotation, then torsional rigidity is achieved, but thermal expansion and vibrations cause fatigue failures
Solution Approach 1:
The fastening element's web components are designed with specific geometric parameters including length, width, and curvature that allow them to maintain torsional rigidity for preventing encoder rotation while simultaneously accommodating thermal expansion and vibration forces. The parameter optimization enables the structure to be both stable and durable under varying operating conditions.
3Ease of manufacture
If conventional mounting is used, then the encoder can be installed, but concentricity errors and tolerances lead to misalignment
Solution Approach 1:
The web components feature asymmetric geometry with varying thickness and curvature profiles that compensate for concentricity errors and manufacturing tolerances. The asymmetric design allows the fastening element to self-align with the encoder shaft, reducing misalignment issues while maintaining ease of installation through a straightforward mounting process.
4Force
If rigid fastening is used to support encoder housing, then torsional connection is achieved, but vibrations and thermal expansion cause fatigue fractures
Solution Approach 1:
The fastening element transitions from conventional planar mounting to a three-dimensional web structure that extends radially outward from the ring. This dimensional change creates multiple stress distribution paths through the web geometry, allowing the structure to maintain strong torsional connection forces while distributing vibrational and thermal stresses across multiple dimensions, thereby preventing fatigue fractures.
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a fastening element (1), in particular a torque support, for fastening a rotary encoder (21) with an encoder shaft to a housing (22), said fastening element comprising: a ring (2) by means of which the encoder shaft can be enclosed; at least two first recesses (3) by means of which the fastening element (1) can be fastened to the rotary encoder (21) or to the housing (22); at least two second recesses (4) by means of which the fastening element (1) can be fastened to the housing (22) or to the rotary encoder (21); and at least two bars (5) which each extend radially outwardly or inwardly from a connection region (6) of the ring (2) and which each comprise one of the second recesses (4), wherein each connection region (6) is located closer to one of two adjacent first recesses (3) in the positive peripheral direction (30), and each bar (6) extends towards the other of said two adjacent first recesses (3) in the negative peripheral direction (31). The invention also relates to a machine (23) comprising such a fastening element (1). In order to provide an improved fastening element (1) or an improved machine (23), according to the invention each additional bar (7) extends in the axial direction and each first recess (3) is located in the region of the axial end of the associated additional bar (7).