Resolver Rotor Hexagon for Shaft Deformation
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Solution Overview
Problem
The existing emergency or safety turning devices in electric machines, such as robot drives, face issues with plastic deformation of the shaft end due to high surface loads, leading to unreliable tool engagement and potential failure, necessitating frequent tool application or shaft replacement.
Innovation Solution
The electrical machine incorporates a resolver with a rotor pin featuring an external polygon for increased active surface area, secured by a feather key connection, and a braking device with a locking mechanism to generate sufficient holding torque, allowing for non-destructive torque transmission and preventing deformation during emergency or safety rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the shaft end is directly provided with external hexagon or parallel wrench surfaces for manual rotation, then the emergency turning function is enabled, but the active surfaces undergo plastic deformation due to high surface loads
Solution Approach 1:
The patent extracts the emergency rotation function from the shaft end and relocates it to the resolver rotor. The external hexagon is now formed on the resolver rotor instead of the shaft end, separating the manual rotation interface from the high-stress shaft structure. This allows the shaft end to maintain its original function without deformation while the resolver rotor provides the emergency rotation capability.
Solution Approach 2:
The resolver rotor acts as an intermediary component between the handling tool and the machine shaft. Instead of applying torque directly to the shaft end, the tool engages the resolver rotor which then transmits the torque through its feather key connection to the shaft. This intermediary protects the shaft from direct high surface loads.
2Volume of moving object
If the shaft diameter is kept relatively small for compact design, then the machine size is reduced, but the active surfaces deform under high torque loads
Solution Approach 1:
The patent extracts the torque transmission interface from the shaft and relocates it to the resolver rotor. The external hexagon is now formed on the resolver rotor instead of the shaft end, separating the manual rotation interface from the high-stress shaft structure. This allows the shaft end to maintain its original function without deformation while the resolver rotor provides the emergency rotation capability.
Solution Approach 2:
The patent moves the emergency rotation interface from the axial dimension (shaft end) to the radial dimension (resolver rotor circumference). The external hexagon is now formed on the resolver rotor which has a larger effective diameter, providing better leverage and distributing the torque loads over a larger area, thereby preventing deformation.
3Device complexity
If the shaft end is used for emergency rotation, then the manual turning function is integrated, but the motor must be replaced when the shaft end deforms
Solution Approach 1:
The patent extracts the emergency rotation function from the shaft end and relocates it to the resolver rotor. The external hexagon is now formed on the resolver rotor instead of the shaft end, separating the manual rotation interface from the high-stress shaft structure. This allows the shaft end to maintain its original function without deformation while the resolver rotor provides the emergency rotation capability.
Solution Approach 2:
The patent creates a duplicate torque transmission path through the feather key connection between the resolver rotor and the shaft. This redundant connection ensures that the resolver rotor can effectively transmit torque to the shaft without requiring direct modification of the shaft end, thereby protecting the original shaft structure.
4Ease of operation
If the external hexagon is formed on the shaft end, then the handling tool can be applied directly, but the surface load causes deformation and loss of form-fitting engagement
Solution Approach 1:
The patent extracts the external hexagon from the shaft end and relocates it to the resolver rotor. This separates the tool engagement interface from the high-stress shaft structure, allowing the shaft end to maintain its original precision geometry while the resolver rotor provides the emergency rotation interface.
Solution Approach 2:
The resolver rotor acts as an intermediary component between the handling tool and the machine shaft. Instead of applying torque directly to the shaft end, the tool engages the resolver rotor which then transmits the torque through its feather key connection to the shaft. This intermediary protects the shaft from direct high surface loads.
Data Source
Figure 1
AI summary
The invention relates to an electrical machine (1) comprising, in a machine housing (2), a machine stator (15) and a machine rotor (16) on a machine shaft (4), the shaft end (7a) of which is led out of the machine housing (2) in the region of a housing space (9) for a bearing shield. The shaft end (7a) carries a nut (22) which can be rotated relative to an inner and/or outer axial stop (21a or 24) to manually rotate the machine shaft (7). If the machine has a resolver (21), a corresponding effective surface (26') for manually rotating the shaft can be provided also on a rotor journal (27) of the resolver (21).