Transmission-Mounted Resolver Layout for Low-Cost Motor Speed Sensing
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Solution Overview
Problem
Existing work vehicles face challenges in detecting the rotation speed of a motor generator at a low cost, requiring efficient and cost-effective methods.
Innovation Solution
The work vehicle incorporates a resolver configured to measure the rotation speed of the motor generator, housed in a transmission case with a wall section supporting the resolver's stator, allowing detection without a special interlocking mechanism, and utilizing supports and gaps for cooling and easy installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a special interlocking mechanism is provided to connect the rotary shaft and rotor, then the detection reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The rotary shaft itself serves as the interlocking mechanism by directly rotating the rotor through its own rotation, eliminating the need for separate interlocking components. The rotary shaft's rotation automatically drives the rotor,实现ing self-service functionality.
Solution Approach 2:
The rotary shaft performs dual functions: it transmits mechanical power and simultaneously serves as the interlocking mechanism for the rotor. This multi-functionality reduces the need for additional specialized components.
2Temperature
If the resolver is positioned far from the wall section, then the cooling effect is improved, but the space required increases
Solution Approach 1:
Instead of increasing the radial distance from the wall section for cooling, the design utilizes the axial dimension by creating gaps between the resolver and wall section in the axial direction. This dimensional shift allows effective cooling while maintaining compact radial spacing.
Solution Approach 2:
The cooling approach is segmented into multiple gaps created at different locations around the resolver, allowing distributed cooling pathways that are more effective than a single large distance while occupying minimal space.
3Temperature
If multiple supports are provided at dispersed locations, then the cooling efficiency and workability are improved, but the manufacturing complexity increases
Solution Approach 1:
The support structure is divided into multiple discrete supports positioned at dispersed locations around the resolver. Each support creates its own cooling gap, and the segmented approach allows for standardized manufacturing of individual supports that are then assembled in a pattern.
Solution Approach 2:
Each support location provides localized cooling functionality tailored to the specific thermal conditions at that position around the resolver. The dispersed supports create locally optimized cooling pathways without requiring a complex overall structure.
4Ease of operation
If the stator is joined from the side opposite to the wall section, then the ease of assembly is improved, but the structural complexity increases
Solution Approach 1:
Instead of joining the stator from the conventional side (the side where the wall section is located), the design inverts the assembly approach by joining from the opposite side. This reversal of the joining direction allows for easier access during assembly without requiring complex internal fastening mechanisms.
Data Source
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AI summary
A rotation speed of a motor generator can be detected at a low cost in a work vehicle in which the motor generator is joined to a transmission that changes the speed of motive power from an engine to output it to travel devices. A transmission case 13 housing a transmission has a wall section 37a through which rotary shafts 21a and 22a of motor generators 21 and 22 are inserted. Rotors 41a and 42a of resolvers 41 and 42, which detect the rotation speed of the motor generators 21 and 22, are fitted onto the respective rotary shafts 21a and 22a. Stators 41b and 42b of the resolvers 41 and 42 are supported by the wall section 37a.