Wheel Loader Transmission Control for Rapid Downshifting

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Solution Overview

Problem

Conventional wheel loaders require complex and time-consuming operations to shift to the lowest speed position for excavation, making it difficult for operators to quickly approach excavation sites efficiently, especially on flat ground.

Innovation Solution

A wheel loader equipped with a transmission control system that includes a shiftdown switch, speed sensor, and tilting angle detector, allowing for easy speed position changes with a single operation, either downshifting one speed position at a time or directly to the lowest speed position based on vehicle speed and inclination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the transmission is downshifted one speed position by each operation of the operation device, then the speed position can be changed step by step, but it takes too much time to reach the lowest speed position quickly

Engineering Contradiction:
Improvestep-by-step speed position changeVSAvoidtime to reach lowest speed position
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent implements dynamic shift control where the transmission control device automatically adjusts the shifting pattern based on real-time conditions. When the vehicle approaches the excavation object (detected by proximity sensors), the system dynamically switches from gradual one-step-downshifting to direct downshifting to the lowest speed position, optimizing both operational control and response time.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control system monitors vehicle speed, distance to excavation object, and current transmission speed position as variable parameters. Based on these parameters, the system dynamically determines the appropriate downshifting strategy - either incremental one-step changes or direct jumps to the lowest position - thereby adapting the shifting behavior to the specific operational context.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple operation devices are used for downshifting, then speed position control is possible, but the operation becomes complicated and difficult for unexperienced operators

Engineering Contradiction:
Improvespeed position control capabilityVSAvoidoperator complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent merges the functions of multiple operation devices into a single integrated shiftdown switch. This single switch communicates with a transmission control device that handles all the complex logic for determining when and how to downshift, consolidating multiple control functions into one user interface element while maintaining full speed position control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transmission control device performs self-service by automatically monitoring vehicle conditions (speed, position, distance to object) and autonomously determining the appropriate downshifting action. The operator simply operates the shiftdown switch, and the system self-manages the complex control logic, eliminating the need for the operator to understand or manage multiple operation devices.

Inventive Principle:
Principle #25Self-service

3Speed

If the vehicle travels at high speed with high speed position toward the excavation object, then arrival time is reduced, but the transmission must be changed to first speed just before the object

Engineering Contradiction:
Improvetraveling speed to excavation objectVSAvoidtime for final speed position change
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The system performs preliminary action by detecting the approach to the excavation object in advance using proximity sensors and distance measurement. Before the vehicle actually reaches the object, the transmission control device anticipates the need for downshifting and initiates the speed position change proactively, ensuring the transmission is already in the correct low-speed position when the vehicle arrives at the excavation site.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from proximity sensors and speed sensors to continuously monitor the vehicle's approach to the excavation object. This real-time feedback enables the transmission control device to make informed decisions about when to initiate downshifting, optimizing the timing to maintain high speed during approach while ensuring timely speed reduction before reaching the object.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3660356B1Work vehicle
Publication Date: 2022.07.13 HITACHI CONSTRUCTION MACHINERY CO LTD
  • EP3660356B1 patent drawingFigure 1
  • EP3660356B1 patent drawingFigure 2
  • EP3660356B1 patent drawingFigure 3~4A

AI summary

Provided is a wheel loader in which the speed position of the transmission can be easily changed with a small number of switches. The wheel loader 1 includes a tilting angle sensor 9 for detecting the tilting angle of the vehicle body. in case that the vehicle body is traveling on an uphill or a downhill with a transmission 33 in a higher speed position than the lowest speed position, and the tilting angle detected by the tilting angle sensor 9 is not smaller than a prescribed threshold value, a transmission control device 45 sends the transmission 33 a command to downshift the transmission 33 one speed position by each operation of a shiftdown switch 62.