Rotor Winding Wire Guidance for Commutator Machines
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Solution Overview
Problem
The existing methods for producing rotor windings in electrical machines face issues with wire guiding on connection lugs, leading to potential short circuits and torque ripple due to resilient expansion of wire eyelets and inadequate coil distribution.
Innovation Solution
The method involves guiding the winding wire between two pole teeth for a portion of coils, ensuring a sufficient wrap on connection lugs and reducing torque ripple by distributing coils with angular errors across two opposing pole teeth, and using a supporting ring for additional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the winding wire is directly guided from the slot to the connection lug of the lamination, then the wire guiding path is shortened, but the wire eyelet resiliently expands causing short circuits between adjacent connection lugs
Solution Approach 1:
The patent introduces an intermediary structure (the lamination with connection lug) between the winding wire and the slot. The winding wire is guided through the slot, around the connection lug, and back through the slot, creating a secure eyelet configuration. This intermediary path prevents direct contact between adjacent wires while maintaining electrical connection, thereby preventing short circuits between adjacent connection lugs.
2Reliability
If the winding wire is guided across a large circumferential area to the connection lug, then the wire can be securely connected, but the wire slips onto previous winding wires impeding further contacts
Solution Approach 1:
Instead of guiding the wire across the circumferential area to the connection lug and then back (the conventional path), the patent inverts the sequence by first passing the wire through the slot, then around the connection lug, and finally back through the same slot. This inverted path eliminates the problem of wire slippage onto previous winding wires while maintaining secure connection, thereby enabling continuous high-speed coil winding.
3Ease of manufacture
If the connecting wires are hooked at an acute angle on the connection lugs, then the wire eyelet is formed, but the eyelet resiliently expands reducing manufacturing precision
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming the wire eyelet through the hot staking process before the coil is installed and subjected to operational forces. The hot staking process melts the insulating varnish and fuses the wire to the connection lug, creating a rigidified eyelet structure. This preliminary strengthening prevents subsequent resilient expansion that would otherwise occur under mechanical stress, thereby maintaining manufacturing precision throughout the product lifecycle.
Data Source
AI summary
The invention relates to a method for producing the rotor winding of an electrical machine having at least four exciter poles in the stator (11) and having a commutator rotor (13) with a number of slots (N) and pole teeth (Z) which deviates from the number of exciter poles, and having a number of individual tooth coils (S) and laminations (L) which is at least twice as high as the number of pole teeth, wherein the individual tooth coils are wound, starting from the first coil (S1) onto in each case that pole tooth with the lowest angular error (Wf) in relation to a pole division (Pt). In order to permit non-critical guidance of the winding wire (17) in the region of the lamination connections, provision is made, at least in the case of a last-wound section (B) of the coils (S), preferably in the case of all of the coils, for the winding wire (17), with which contact is made by a lamination (L) in each case between two coils (S), to be fed from one side of the lamination (L) and guided away from the other side, and for at least one pole tooth (Z), but at most two pole teeth (Z) to be situated between the slot (N) from which the winding wire (17) of the lamination (L) is fed and the slot (N) at which said winding wire is guided away from the lamination (L).