Unified Transmission Control for Variable Speed Vehicles

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Solution Overview

Problem

Self-propelled vehicles with separate control devices for speed and direction reversal can lead to operator handling errors, resulting in jerking or transmission issues, especially when equipped with nonprogressive clutch mechanisms, increasing costs due to the need for progressive clutch systems.

Innovation Solution

A transmission system with a single control device that selectively manages both variable speed drive and direction reversal, using a belt transmission and a mechanism that allows forward and reverse travel without jerking, even with nonprogressive clutches, by integrating a speed changing control device and a direction reversal mechanism into a shared control system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If separate control devices are used for speed changing and direction reversal, then each function can be controlled independently, but operator handling errors occur leading to jerking or transmission damage

Engineering Contradiction:

Improveindependent control of speed and directionVSAvoidrisk of operator handling errors

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent combines the speed changing control device and direction reversal control device into a single integrated control mechanism. This unified controller manages both functions simultaneously, eliminating the risk of operator handling errors that occur with separate controls while maintaining independent control capability through sequential actuation of speed and direction functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The control device is designed to perform multiple functions: it controls both the variable speed drive mechanism and the direction reversal mechanism. This multi-functional controller reduces complexity and eliminates the need for operators to coordinate multiple separate controls, thereby preventing handling errors.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If progressive clutch mechanisms are used to prevent jerking during direction reversal, then smooth operation is achieved, but vehicle cost increases

Engineering Contradiction:

Improvesmooth direction reversal without jerkingVSAvoidvehicle manufacturing cost

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

The control device is designed to automatically disengage the variable speed drive before actuating the direction reversal mechanism. This preliminary action ensures that the clutch operates under optimal conditions (with the variable speed drive disengaged), enabling smooth reversal without jerking even using simpler, less expensive non-progressive clutch mechanisms.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the operational state of the variable speed drive based on the control sequence. By automatically disengaging the variable speed drive during direction reversal operations, the system creates optimal dynamic conditions for clutch operation, achieving smooth reversal with less expensive clutch mechanisms.

Inventive Principle:

Principle #15Dynamics

3Reliability

If a single control device is used for both speed and direction control, then operator handling errors are prevented, but control device complexity increases

Engineering Contradiction:

Improveelimination of operator handling errorsVSAvoidcontrol device structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The single control device is designed with distinct operational phases or segments: one phase for speed changing and another phase for direction reversal. This segmentation allows the controller to manage multiple functions through a unified interface without requiring complex simultaneous coordination, reducing overall system complexity while maintaining reliability.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution simplifies operator control by using a single control device for speed and direction, preventing mishandling and jerking, while allowing wide-range speed variation and reducing costs by enabling the use of nonprogressive clutch mechanisms.

Implementation Method 1

a belt transmission between at least one drive pulley and one driven pulley

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8197368B2Transmission system for a self-propelled vehicle with variable travel speed, its control device, and vehicle equipped with such a transmission system

Publication Date: 2012.06.12 FRANCE REDUCTEURS SA

AI summary

A system for a self-propelled vehicle with variable travel speed, such as a mowing tractor, includes, between the primary driving shaft of the vehicle and an output shaft, such as the wheel drive shaft of the vehicle, at least one controlled variable speed drive with a belt and controlled mechanism for reversing the direction of travel of the vehicle, the primary driving shaft transmitting, via the variable speed drive, its motion to the input shaft of the reversal mechanism, itself able to directly or indirectly engage the output shaft, such as the wheel drive shaft of the vehicle, in such a way as to allow the vehicle to travel forward or in reverse respectively, at a variable travel speed. This transmission system is characterized in that the variable speed drive and the mechanism for reversing the direction of travel of the vehicle are controlled selectively from the same control device.