Friction Clutch Sensor Spring Lever Geometry
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Solution Overview
Problem
Conventional friction clutches experience undesired readjustment due to increasing release force with wear, leading to safety concerns and inefficient overtravel, as the characteristic curve of the disc spring can result in unwanted re-engagement.
Innovation Solution
A friction clutch design with a sensor spring that increases its force over the release path, featuring a crowned contact surface and a ball mechanism to change the lever geometry, ensuring the intersection point of release force and sensor spring force is outside the maximum release path, preventing undesired readjustment and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor spring force is increased to prevent unwanted readjustment, then readjustment stability improves, but the overtravel safety margin decreases
Solution Approach 1:
The dynamic lever length adjustment allows the sensor spring to provide appropriate force at different positions along the release path. During normal operation with sufficient overtravel, the lever remains relatively long, keeping sensor force moderate. Only when the plate spring approaches the maximum release path does the lever shorten significantly, increasing sensor force to prevent readjustment. This dynamic behavior maintains both safety margin and readjustment stability.
Solution Approach 2:
The crowned contact surface is pre-designed with specific geometric parameters (curvature radius, positioning) that automatically guide the lever length change sequence. This preliminary geometric configuration ensures that the lever lengthens appropriately during normal operation to maintain safety margins, while automatically shortening only when needed near the end of the release path to prevent readjustment, without requiring active control.
2Reliability
If the lever length of the sensor spring is shortened to increase sensor spring force, then readjustment prevention improves, but the release force characteristic curve changes unfavorably
Solution Approach 1:
The lever length is made dynamic through the crowned contact surface, automatically adjusting during the release path movement. This dynamic adjustment ensures that the lever is long during most of the release path to maintain favorable release force characteristics, and only shortens near the end to provide the necessary sensor force for readjustment prevention. This temporal separation of functions resolves the contradiction between release force quality and readjustment prevention.
Solution Approach 2:
The crowned contact surface geometry is pre-configured with specific curvature and positioning parameters that automatically control the lever length sequence. This preliminary geometric design ensures that the lever lengthens during normal release operation to maintain good release force characteristics, while automatically shortening only when the plate spring approaches the maximum release path, providing readjustment prevention without compromising overall release force quality.
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 design achieves increased overtravel and improved release force behavior by ensuring the sensor spring force intersects with the release force at a safe margin, preventing unwanted re-engagement and enhancing the safety of the friction clutch.
Implementation Method 1
A friction clutch design with a sensor spring that increases its force over the release path, featuring a crowned contact surface and a ball mechanism to change the lever geometry
Implementation Method 2
a ball mechanism to change the lever geometry, ensuring the intersection point of release force and sensor spring force is outside the maximum release path
Implementation Method 3
clutch disc with wear-prone friction linings
Data Source
Figure 1
Figure 2~3
Figure 4~7
AI summary
The invention relates to a friction clutch having: a counter-pressure plate and a cover connected thereto; a pressing plate connected for conjoint rotation to the cover by means of leaf springs and movable axially with respect to the counter-pressure plate against the force of the leaf springs; a disc spring that loads the pressing plate with a closing force against the counter-pressure plate at an operating point with the friction clutch engaged and which is supported on the cover and is actuated with a disengagement force during actuation of the friction clutch, overcoming the closing force, on plate spring tongues axially along a disengagement path; a clutch disc with wear-prone friction linings that can be tensioned between counter-pressure plate and pressing plate; and an adjusting device compensating for the wear, with a sensor spring that is arranged between cover and disc spring which yields axially depending on a disengaging force which increases based on wear and releases an adjusting ring, pre-tensioned in the circumferential direction on the opposing side, of a ramp system arranged between disc spring and cover for compensating a stop on the disc spring to be adjusted on the basis of wear. In order to ensure there is no undesired adjustment of the friction clutch for large disengagement paths and to achieve an excess travel relative to a maximum disengagement path of an undesired adjustment, a sensor spring force of the sensor spring acting against the disc spring is provided so as to increase across the disengagement path.