Disc Brake Caliper Worm-Gearbox Integration for Reduced Axial Size

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Solution Overview

Problem

Existing disc brake calipers are cumbersome due to their large axial dimensions, particularly in motorcycles, where reduced width and maneuverability are constrained by the side-by-side arrangement of the piston and worm-nut screw assembly and gearbox, which cannot be effectively minimized.

Innovation Solution

The integration of gearbox components with the thrust device, using a single thrust bearing to support both the worm and gearbox, reduces the axial size by eliminating unnecessary components and simplifying assembly, allowing for a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the piston and worm-nut screw assembly and gearbox are arranged side-by-side, then the braking function is achieved, but the axial dimensions of the caliper become large

Engineering Contradiction:
Improvebraking functionVSAvoidaxial dimensions
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent merges the thrust device and gearbox into a single integrated unit. The thrust bearing serves dual purposes: supporting the worm of the thrust device and supporting the gearbox. This consolidation eliminates the need for separate support structures and reduces the axial space required for housing both components side-by-side, thereby resolving the contradiction between maintaining braking function and reducing axial dimensions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The gearbox is positioned within the space occupied by the thrust device housing. The thrust bearing is strategically placed to support both the worm (part of the thrust device) and the gearbox simultaneously. This nested arrangement allows the gearbox to occupy space that would otherwise be wasted, effectively nesting one functional element within another and reducing the overall axial footprint while maintaining both braking and motion transmission functions.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If separate support structures are used for the worm and gearbox, then the components are well-supported, but the assembly becomes complex and occupies more space

Engineering Contradiction:
Improvecomponent supportVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thrust bearing is designed as a universal support element that performs multiple functions simultaneously. It supports the worm of the thrust device and also supports the gearbox, eliminating the need for separate support structures. This multi-functionality reduces assembly complexity by decreasing the number of components and simplifying the support system, while maintaining reliable support for both the worm and gearbox.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly reduces the axial dimensions of the caliper, enhancing maneuverability and reducing the overall size of the assembly, while maintaining effective motion transmission and braking performance.

Implementation Method 1

said worm being rotatably supported by a thrust bearing adapted to support said worm and to apply for said worm an axial reaction

Methodology Applied
Scientific EffectThrust bearing support: Ball Bearing

Implementation Method 2

said worm being operatively connected to a gearbox; at least part of said gearbox being rotatably supported by said thrust bearing

Methodology Applied
Scientific EffectGear reduction: Gear

Data Source

PatentEP3969773B1Brake caliper for disc brake
Publication Date: 2023.04.19 FRENI BREMBO SPA
  • EP3969773B1 patent drawingFigure 1
  • EP3969773B1 patent drawingFigure 2
  • EP3969773B1 patent drawingFigure 3

AI summary

A brake caliper for a disc brake comprising: • - a caliper body (2) adapted to straddle a brake disc to apply a braking action on a vehicle; • - said caliper body comprising at least one thrust device housing (4) which accommodates a thrust device (5) adapted to apply a bias on at least one brake pad to abut said at least one brake pad against the braking surfaces of said brake disc; wherein • - said thrust device (5) is operatively connected to a translating screw nut (9); operatively connected to a worm (10); said translating screw nut (9) is operatively connected to a worm (10); said worm (10) is operatively connected to a gearbox (11); and wherein • - said worm (10) is rotatably supported by a screw thrust bearing (12) adapted to support in rotatable manner said worm (10) and to apply for said worm (10) an axial reaction, i.e. a direct reaction prevalently along said axial direction (A-A); • - at least part of said pressure gearbox (11) placed near and operatively connected to said worm (10) is rotatably supported by at least one gearbox thrust bearing (12) adapted to support in rotatable manner said at least one part of said reduction gear (11) and apply for said at least one part of said reduction gear (11) a radial reaction, that is a direct reaction prevalently along said radial direction (R-R); said thrust bearing (12) comprises at least one radially inner slewing ring (14, 15); and wherein said gearbox (11) comprises an epicyclic gear (20); and wherein said epicyclic gear (20) comprises a fixed gear or an internally toothed body (17) which cooperates with at least one planet gear (18), and wherein said at least one planet gear (18) is rotatably supported about at least one planet gear pin (21); and said at least one planet gear pin (21) is operatively connected to said at least one radially inner slewing ring (15) so as to transmit A brake caliper for a disc brake comprising: • - a caliper body (2) adapted to straddle a brake disc to apply a braking action on a vehicle; • - said caliper body comprising at least one thrust device housing (4) which accommodates a thrust device (5) adapted to apply a bias on at least one brake pad to abut said at least one brake pad against the braking surfaces of said brake disc; wherein • - said thrust device (5) is operatively connected to a translating screw nut (9); operatively connected to a worm (10); said translating screw nut (9) is operatively connected to a worm (10); said worm (10) is operatively connected to a gearbox (11); and wherein • - said worm (10) is rotatably supported by a screw thrust bearing (12) adapted to support in rotatable manner said worm (10) and to apply for said worm (10) an axial reaction, i.e. a direct reaction prevalently along said axial direction (A-A); • - at least part of said pressure gearbox (11) placed near and operatively connected to said worm (10) is rotatably supported by at least one gearbox thrust bearing (12) adapted to support in rotatable manner said at least one part of said reduction gear (11) and apply for said at least one part of said reduction gear (11) a radial reaction, that is a direct reaction prevalently along said radial direction (R-R); said thrust bearing (12) comprises at least one radially inner slewing ring (14, 15); and wherein said gearbox (11) comprises an epicyclic gear (20); and wherein said epicyclic gear (20) comprises a fixed gear or an internally toothed body (17) which cooperates with at least one planet gear (18), and wherein said at least one planet gear (18) is rotatably supported about at least one planet gear pin (21); and said at least one planet gear pin (21) is operatively connected to said at least one radially inner slewing ring (15) so as to transmit the action of said gearbox (11) to said worm (10) by means of said at least one radially inner slewing ring (15).