Friction Damper With Prestressing Means For Force Control
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Solution Overview
Problem
Existing friction devices for controlling force in damping systems are unreliable due to dependence on the coefficient of friction of the materials used, leading to uncertainties in restored force and stability over time, and often operate in an 'all or nothing' manner without directional control.
Innovation Solution
A friction device with prestressing means that allows for precise control of force independently of friction coefficients, featuring a movable member with rotational or translational movement, and adjustable prestressing elements such as elastic washers and balls to manage friction torque, enabling directional control and damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If friction devices use normal pressure force to control force, then the force control is directly dependent on the coefficient of friction, but this leads to uncertainties about the restored force and its repetitiveness and stability over time
Solution Approach 1:
The invention changes the controlling parameter from friction-dependent normal pressure to prestressing force applied by elastic elements. The prestressing force is independently controllable and not dependent on friction coefficients, thereby improving the reliability and stability of the restored force over time.
Solution Approach 2:
Elastic prestressing elements (such as springs or elastomers) are introduced as intermediary components between the friction surfaces and the external loading system. These intermediaries provide controlled prestressing forces that decouple the force control from direct friction dependence, enhancing reproducibility and stability.
2Ease of operation
If friction devices operate with springs that pressurize friction elements, then the pressure is applied in one direction while suppressed in the other direction, but this creates an 'all or nothing' operation that does not allow control of the force
Solution Approach 1:
The invention transitions from a static binary operation mode to a dynamic continuous control mode. The prestressing elements allow gradual adjustment of the pressing force on friction surfaces, enabling proportional control in both directions of movement rather than abrupt engagement or disengagement.
Solution Approach 2:
The prestressing mechanism is designed to function effectively in both directions of relative movement between friction surfaces. The elastic elements can simultaneously provide prestressing force for both compression and tension operations, eliminating the need for direction-specific activation.
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 solution provides precise control of force and damping, reducing dependence on friction coefficients and eliminating 'all or nothing' operation, allowing for calibrated damping in one direction while enabling movement control in the opposite direction.
Implementation Method 1
said pressing forces are produced by prestressing means
Implementation Method 2
transform said external stress into a friction force
Implementation Method 3
the members are mobile, or potentially mobile, with respect to one another in a rotational movement and are associated with means for transforming rotational movement in rectilinear motion
Data Source
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AI summary
Friction device comprising at least two members (1, 15), one of which is mobile, or potentially mobile, in terms of relative displacement with respect to the other under the action of an external stimulus (P), and in which the relative displacement is liable to cause the relative displacement of two friction surfaces subjected to pressing forces, so as to convert the external stimulus (P) into a friction force and thus control the displacement of the mobile or potentially mobile member. The pressing forces are produced by prestressing means (17) and the members (1, 15) are designed such that they are able to act on the effects of the prestressing means (17) so as to use the resultant effect of the relative displacement of the mobile or potentially mobile member to reduce the pressing forces.