Hydraulic Lawn Mower Transmission for Constant Blade Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lawn mowers face challenges in suppressing fuel consumption while maintaining output performance and integrating the transmission unit with the transmission case for improved assemblability.
Innovation Solution
A transmission unit with a first and second gear train, hydraulic clutches, and a hydraulic circuit integrated into the transmission case, allowing switching between rotation speeds to maintain a predetermined mowing-blade rotation speed and reduce fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine speed is kept constant to maintain the mowing-blade rotation speed, then the output performance is secured, but the fuel consumption increases
Solution Approach 1:
The patent applies dynamics by making the transmission system adjustable through multiple gear trains and clutches. The transmission ratio can be dynamically changed based on engine speed conditions, allowing the system to adapt between maintaining constant output speed or reducing input speed requirements, thereby resolving the contradiction between output stability and fuel consumption.
Solution Approach 2:
The patent changes the transmission ratio parameter by switching between different gear trains (first, second, third gear trains) with different reduction ratios. When the engine operates at lower speeds, a gear train with a smaller reduction ratio is selected, allowing the engine to operate at more fuel-efficient speeds while still achieving the required mowing-blade rotation speed.
2Ease of manufacture
If the transmission unit is integrated with the transmission case, then the assemblability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the transmission unit with the transmission case by forming the hydraulic circuit directly within the transmission case. The transmission case houses not only the mechanical transmission components (input shaft, output shaft, gear trains) but also the hydraulic control system, eliminating the need for separate external hydraulic units and improving assemblability.
Solution Approach 2:
The transmission case serves multiple functions: it acts as the housing for mechanical transmission components, the reservoir for hydraulic fluid, and the structure containing the hydraulic circuit. This multi-functionality reduces the number of separate components needed, simplifying the overall system while maintaining complex internal functionality.
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
The transmission unit achieves reduced fuel consumption while securing output performance by maintaining a constant mowing-blade rotation speed, with improved assemblability through integration with the transmission case.
Implementation Method 1
a hydraulic circuit that supplies hydraulic pressure to hydraulic chambers of the first clutch and the second clutch is formed in a transmission case
Data Source
AI summary
A transmission unit includes an input shaft to which motive power from a drive source is input, an output shaft, first and second gear trains provided between the input shaft and the output shaft, first and second clutches that respectively switch the first and second gear trains to a power transmission state or a non-power transmission state, and a transmission case. When the drive source is switched between first and second rotation speeds, the output shaft is rotationally driven at a predetermined rotation speed. Each of the first and second clutches is a hydraulic clutch. A hydraulic circuit that supplies hydraulic pressure to hydraulic chambers of the first and second clutches is formed in the transmission case.