Cam-Actuated Clutch Pressure Plate for Reduced Engine Braking
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Solution Overview
Problem
Existing clutches in vehicles lack an effective mechanism to automatically reduce torque transmission when the driving wheel speed exceeds the engine rotation speed, leading to excessive engine braking effects.
Innovation Solution
A clutch design featuring a first cam profile integral with the driven member and a second cam profile integral with the pressure plate, which generates an axial thrust to move the pressure plate away from the driven member, reducing torque transmission without the need for an axial stop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If cam profiles are used to generate axial movement of the pressure plate away from the driven member to reduce torque transmission, then the engine braking effect is reduced, but the axial stroke is limited by an axial stop causing impact loads
Solution Approach 1:
The patent introduces an elastic member (spring) as an intermediary between the pressure plate and the driven member. This elastic member absorbs the impact energy when the pressure plate moves away from the driven member, replacing the rigid axial stop with a compliant element that gradually absorbs the shock rather than creating a sudden impact load.
Solution Approach 2:
The elastic member is pre-installed in the system to provide cushioning before any impact occurs. When the cam profiles generate axial movement of the pressure plate, the elastic member is already in place to absorb the resulting motion, preventing the harmful impact that would occur without this pre-positioned cushioning element.
2Loss of energy
If the pressure plate is moved away from the driven member to reduce torque transmission, then the coupling loss is prevented, but the axial movement requires additional space and structural complexity
Solution Approach 1:
The patent combines multiple functions into the pressure plate assembly: the pressure plate itself, the elastic member for cushioning, and the cam profile interaction for axial movement generation. By merging these elements into a integrated assembly, the design achieves the required axial movement capability while minimizing additional structural complexity and space requirements.
Solution Approach 2:
The system uses dynamic interaction between the cam profiles to generate the necessary axial movement of the pressure plate. Rather than requiring a complex mechanical linkage or motorized actuation system, the dynamic geometry of the cam profiles automatically produces the axial motion needed to prevent coupling loss when driving wheel speed exceeds engine speed.
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 effectively reduces the engine braking effect by allowing the clutch to slip slightly, thereby limiting the torque transmitted and preventing undesirable effects such as coupling loss between driven discs and the driven member.
Implementation Method 1
a first cam profile integral with the driven member, and coacting with a second cam profile integral with the pressure plate. The first cam profile and the second cam profile are configured so that, if a torque is transferred from the driven member toward the drive input member, the driven member rotates relative to the pressure plate about the axis of the clutch and the rotation movement between the driven member and the pressure plate generates, by means of the first cam profile and the second cam profile, an axial thrust on the pressure plate
Implementation Method 2
The pressure plate is elastically stressed toward the driven member to compress the first discs and the second discs against one another
Implementation Method 3
a pressure plate that presses the friction discs against one another, so that they transmit the torque from the drive input member to the driven member by friction
Data Source
AI summary
A clutch (1) includes a housing (3) connected to a drive input member (5). First friction discs (7) are mounted in the housing and rotate therewith. Second friction discs (9) are mounted on a driven member (11). A pressure plate (13) is elastically stressed toward the driven member to compress the first and the second friction discs (7, 9) against one another. Cam profiles (31, 33) integral with the driven member and with the pressure plate, generate a thrust to move the driven member and pressure plate away from each other when it is necessary to reduce the pressure exerted by the pressure plate on the first and second friction discs. An angular stroke limiter limits the relative rotation between the driven member and the pressure plate and thereby limits the movement of the pressure plate away from the driven member).