Disc Brake Return Spring With Wear-Compensating Pad Separation
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Solution Overview
Problem
Disc brakes experience premature wear and overheating due to insufficient separation of brake pads from the disc, leading to residual torque and decreased vehicle performance, with existing solutions requiring complex machining and assembly for the elastic return spring design.
Innovation Solution
A disc brake design featuring an axial elastic return spring made from a single piece of material, with a "C"-shaped slide and stabilizing tab, that compensates for wear play by deforming plastically when the brake pad travels beyond the operating clearance, simplifying the manufacturing and assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the elastic return spring uses a complex hairpin shape with folded tabs to attach to the fixed support, then the attachment is secure, but the machining becomes difficult and assembly becomes complex
Solution Approach 1:
The elastic return spring is divided into distinct functional segments: a fixing portion with a blade for secure attachment to the fixed support, a connecting branch for attachment to the braking pad, and a plastically deformable section for wear compensation. This segmentation allows each part to be optimized independently for its specific function while simplifying the overall manufacturing process.
Solution Approach 2:
Instead of using a complex hairpin shape with folded tabs that requires broaching operations, the invention inverts the approach by using a simple blade-shaped fixing portion that can be directly machined or formed. The attachment security is achieved through the blade geometry and its fit into the housing notch, eliminating the need for complex folding and tab structures.
2Reliability
If the elastic return spring uses a hairpin shape with overlapping attachment portion, then the attachment is secure, but the assembly becomes complex when the housing comprises a slide
Solution Approach 1:
The spring structure is segmented into a fixing portion, connecting branch, and plastically deformable section. The fixing portion with its blade geometry is designed to work independently with the housing notch, while the connecting branch interfaces with the braking pad. This segmentation eliminates the overlapping issues inherent in hairpin designs and simplifies assembly when slides are present.
Solution Approach 2:
The invention inverts the traditional hairpin attachment approach by using a blade-shaped fixing portion that inserts into a machined notch in the housing. This inverted approach eliminates the need for complex tab folding and overlapping structures, thereby simplifying assembly especially when the housing includes slides for brake pad movement.
3Ease of operation
If the brake pad sliding is of insufficient quality or seized up, then the brake pad cannot separate from the disc, but the friction lining undergoes premature wear and overheating occurs
Solution Approach 1:
The plastically deformable section is pre-configured to become active when the brake pad stroke exceeds the operating clearance. This preliminary action ensures that even if the brake pad sliding is insufficient or seized, the spring will plastically deform to create additional separation distance, preventing premature wear and overheating of the friction lining.
Solution Approach 2:
The spring transitions from elastic deformation to plastic deformation when the brake pad stroke exceeds the operating clearance. This parameter change in the material behavior allows the spring to permanently elongate and maintain increased separation between the brake pad and disc, preventing harmful friction even when sliding is insufficient or seized.
4Manufacturing precision
If the brake pad stroke exceeds the operating clearance, then wear compensation is needed, but the elastic spring would require complex plastic deformation mechanisms
Solution Approach 1:
The spring is segmented into an elastic portion for normal operation and a plastically deformable section for wear compensation. This segmentation allows the majority of the spring to remain simple and elastic, while only a specific section is designed to undergo plastic deformation, simplifying the overall mechanism while achieving wear compensation.
Solution Approach 2:
Only the connecting branch or a specific section of the spring is designed to be plastically deformable, while the fixing portion and other sections remain elastically deformable. This local quality approach allows wear compensation functionality to be achieved in a localized area without making the entire spring complex.
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 effectively reduces wear and overheating, maintains constant operating clearance, and simplifies the manufacturing and assembly of the disc brake system, ensuring consistent braking performance and reducing the need for complex machining.
Implementation Method 1
the spring comprising at least one plastically deformable section, under the effect of an axial tensile force, forming said means for taking up the wear clearance, this plastically deformable section being shaped to be plastically elongated when the stroke of the braking pad to its active position is greater than the determined operating clearance
Implementation Method 2
said elastic return spring being of axial orientation and comprising at least one section of axial orientation which is elastically deformable by traction between a state of rest and a state of maximum elongation
Data Source
Figure 1
Figure 2~4
Figure 3A~5
AI summary
The invention relates to a disk brake of a motor vehicle comprising a brake disk, a stationary holder, a brake pad mounted such that it slides axially in the stationary holder, and at least one elastic return spring (48) for the elastic return of the brake pad (18) towards the idle position thereof. The elastic return spring (48) comprises a portion for fixing the spring to the stationary holder, which comprises a rigid fixing blade (200) received in a complementary machined part of the stationary holder of the disk brake.