Motor Case Relay Terminal Layout for Work Vehicle Inverters

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Solution Overview

Problem

Existing work vehicles face challenges in ensuring appropriate connection and efficient power transmission between motors and inverters, leading to complex structures and potential water ingress issues.

Innovation Solution

The work vehicle incorporates relay terminals on the outer periphery of the case facing the motor in a radial direction, connecting motors and inverters closely, with motors positioned to overlap relay terminals, and power wires kept short to simplify the structure and prevent water ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the inverter is provided outside the case and connected to the motor through long power wires, then the motor and inverter can be spatially separated for easier installation, but the structure becomes complex and the risk of contact failure due to water ingress increases

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidpower wire length

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent introduces a relay terminal as an intermediary component mounted on the case exterior. The relay terminal serves as a connection interface between the motor (inside the case) and the inverter (outside the case), eliminating the need for long power wires running through the vehicle interior. This mediator approach simplifies the overall structure while maintaining spatial separation for installation flexibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the relay terminal is positioned far from the motor, then the inverter can be placed in a more convenient location, but the power wire length increases and structural efficiency decreases

Engineering Contradiction:

Improveinverter placement flexibilityVSAvoidpower wire length

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The relay terminal is strategically positioned on the exterior surface of the case at a location that optimizes the connection to the motor while allowing the inverter to be mounted in convenient locations. By utilizing the three-dimensional space around the case, the system achieves short power wire lengths without compromising inverter placement flexibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of operation

If the relay terminal protrudes upward from the case, then the terminal may be more accessible for connection, but the floor height must be increased and water ingress risk increases

Engineering Contradiction:

Improveterminal accessibilityVSAvoidwater ingress risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

Instead of making the relay terminal protrude upward from the case (which would increase accessibility but also water ingress risk and floor height requirements), the patent positions the relay terminal on the lateral exterior surface of the case. This inverted approach to terminal positioning maintains accessibility while eliminating the harmful effects of upward protrusion.

Inventive Principle:

Principle #13The other way round (Inversion)

4Power

If the motor and relay terminal are not positioned close to each other, then the motor can be optimally positioned for power transmission, but the power wire length increases and contact failure risk increases

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidcontact failure risk

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent merges the relay terminal positioning with the motor positioning by locating the relay terminal on the case exterior in close proximity to the motor's radial direction. This combined positioning approach ensures short power wire lengths, maintaining both power transmission efficiency and reliability by minimizing the distance between the motor and relay terminal.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4606609A1Work vehicle

Publication Date: 2025.08.27 KUBOTA CORP

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AI summary

Provided is a work vehicle having a motor configured to supply power to a travel device, and in which the motor and an inverter are appropriately connected. The work vehicle includes motors 21 and 22 configured to supply power to the travel device, a case 12 housing the motors 21 and 22, and an inverter provided outside the case 12 and configured to operate the motors 21 and 22. The work vehicle further includes relay terminals 75 and 76 provided on an outer periphery of the case 12, and connected to the motors 21 and 22 and the inverter and connecting the motors 21 and 22 and the inverter to each other. The relay terminals 75 and 76 are provided on the outer periphery of the case 12 at portions facing the motors 21 and 22 in a radial direction of shafts 21a and 22a of the motors 21 and 22.