Disc Brake Caliper Spring Configuration for Pad Detachment
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Solution Overview
Problem
Prior calipers for disc brakes experience residual braking torque and abnormal wear due to misaligned thrust forces, leading to noise and vibration issues during braking and retraction.
Innovation Solution
A caliper design incorporating a first thrust spring with axial and radial components to facilitate pad detachment, combined with a second thrust spring that counteracts friction forces between the pad and axial guide, ensuring axial motion without rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single thrust spring is used to push the pad away from the brake disc, then the pad can be detached in the release step, but the thrust force creates a torque that rotates the pad and causes abnormal wear
Solution Approach 1:
The single thrust spring is divided into two separate thrust springs: a first thrust spring that provides the main axial thrust to detach the pad from the brake disc, and a second thrust spring that applies a counteracting force to eliminate the rotational torque. This segmentation allows each spring to perform its specific function independently, resolving the contradiction between achieving pad detachment and preventing pad rotation.
Solution Approach 2:
The second thrust spring acts as an intermediary element that mediates the harmful rotational effect generated by the first thrust spring. By positioning the second spring's application point and direction appropriately, it creates a counter-torque that balances the rotational moment, thus preventing pad rotation while maintaining the detachment function.
2Ease of operation
If the thrust force is applied away from the rotation axis to detach the pad, then retraction is improved, but friction between the pad and axial guide generates a harmful torque
Solution Approach 1:
The harmful friction force between the pad and axial guide is converted into a beneficial balancing moment by the second thrust spring. Instead of trying to eliminate friction, the invention uses the second spring to create an equal and opposite moment that counteracts the friction-induced torque, thus converting the harmful effect into a balanced state that prevents pad rotation.
3Reliability
If plates or springs are added to exert thrust on the pads, then residual braking torque is reduced, but the device complexity increases
Solution Approach 1:
Both thrust springs are integrated into the same caliper structure and work together to achieve multiple functions: the first spring provides the primary detachment thrust, while the second spring simultaneously counteracts rotational torque. This multi-functional integration minimizes the increase in device complexity while achieving the desired improvement in residual braking torque elimination.
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
Significantly reduces residual braking torque and prevents pad jamming, maintaining efficient braking performance and minimizing wear, thus eliminating noise and vibration issues.
Implementation Method 1
a first thrust spring (48) which exerts a thrust F on the pad (20), said thrust having a first axial component Fa and a first radial component Fr
Implementation Method 2
the second thrust spring (68) being sized in such a way that the second axial component annuls the moment of the friction force exchanged between the pad and the axial guide
Data Source
AI summary
The invention relates to a caliper for disc brake comprising a caliper body which defines a housing compartment for an associated brake disc and houses at least one pair of pads arranged on opposite sides of the housing compartment along an axial direction. The caliper body comprises at least one thrust piston axially operable against the pad, at least one axial guide which supports and guides the pad in the axial direction and a first thrust spring which exerts a thrust on the pad. Said thrust has a first axial component, axially directed in a direction of approach to the pistons, and a first radial component, perpendicular to the axial direction. Advantageously, the caliper body comprises at least one compensation spring which exerts an axial thrust on the pad in a direction of approach to the pistons. The second axial component annuls the momentum given by the friction force exchanged between the pad and the axial guide with respect to the point of application of the first axial component on the pad.