Variable-Speed Transmission with Progressive Clutch Control
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Solution Overview
Problem
Existing belt-controlled variable-speed drive transmissions for automotive engines, such as riding mower engines, cannot vary engine speed continuously from zero to maximum speed without premature wear and require constant force to maintain the clutch in a disengaged position, which is unsafe and inefficient.
Innovation Solution
A transmission system with a progressive friction clutch and a common control mechanism that acts on both the clutch and variable-speed drive unit, allowing continuous speed variation from zero to maximum speed without constant stress, using a multifunction cam to control the clutch, speed variation, and optional braking and direction reversal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-progressive clutch device is used in a belt-controlled variable-speed drive transmission, then the transmission can be simplified in structure, but the engine speed cannot be varied continuously from zero to maximum speed
Solution Approach 1:
The control mechanism is segmented into two distinct control elements: a first control element that operates the clutch device independently, and a second control element that operates the variable-speed drive unit independently. This segmentation allows the clutch and speed variation to be controlled separately, enabling continuous speed variation from zero while maintaining structural simplicity.
2Device complexity
If a single control element is used to control both the clutch device and the variable-speed drive unit, then the control mechanism is simplified, but the clutch device experiences premature wear due to constant stress in the disengaged position
Solution Approach 1:
The control mechanism is divided into two independent control elements instead of a single control element. The first control element operates the clutch device, while the second control element operates the variable-speed drive unit. This segmentation eliminates the need for the clutch to remain under constant stress to maintain disengagement, thereby preventing premature wear and improving reliability.
3Ease of operation
If the clutch device is kept in disengaged position by applying constant force through the control mechanism, then the transmission can be controlled from a single element, but the clutch experiences premature wear
Solution Approach 1:
The control system is segmented into two independent control elements, allowing the clutch to be disengaged without requiring constant applied force. The first control element releases the clutch completely when disengaged, eliminating continuous stress on the clutch components and preventing premature wear while maintaining ease of operation.
4Productivity
If a belt-controlled variable-speed drive unit is used, then continuous speed variation within a determined range is achieved, but the minimum speed is greater than zero
Solution Approach 1:
The transmission system is segmented into two independently controllable components: the clutch device controlled by the first control element and the variable-speed drive unit controlled by the second control element. This segmentation enables the clutch to be completely disengaged (achieving zero speed) while the variable-speed drive unit can still provide continuous speed variation within its operational range, combining both capabilities.
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
Enables continuous, progressive engine speed adjustment from zero to maximum speed with reduced wear and maintenance costs, similar to hydrostatic systems, while ensuring the engine remains stationary in case of control failure.
Implementation Method 1
at least one clutch device (7) of progressive type, preferably a friction clutch
Data Source
AI summary
The invention relates to a transmission, in particular between a drive shaft and a wheel driving shaft of an engine, in particular of an automotive engine, such as a riding mower engine, whereby this transmission is of the belt-controlled variable-speed drive unit type (2) combined with a clutch device (7).This transmission is characterized in that it is equipped with at least one progressive-type clutch device (7), preferably friction-based, and comprises a control mechanism (20) that is common to clutch device(s) (7) and to the variable-speed drive unit (2), whereby this control mechanism (20), in a first step, acts on the clutch device (7) to pass from the disengaged position, so-called of zero speed, to the engaged position that corresponds to the minimum operational speed of the variable-speed drive unit (2), then, in a second step, acts on the speed variation mechanism (6) of the variable-speed drive unit (2) to regulate as desired the speed of the engine that is equipped with such a variable-speed drive unit (2).