Hydraulic Axial Translation Caliper Guide Pin Lubrication
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Solution Overview
Problem
Existing disc brake systems face issues with smooth sliding of guide pins, reliability of caliper motion, and the need for brake pad retraction springs, which affect braking force and consistency.
Innovation Solution
The implementation of a disc brake design featuring hydraulic axial translation with parallel cylindrical guide pins, annular hydraulic seals, and a direct hydraulic connection to the anchor bracket, eliminating the need for brake pad retraction springs and enhancing lubrication and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide pins are made larger and more rigid to improve stability, then reliability of caliper motion improves, but device complexity increases
Solution Approach 1:
The patent combines the guide pin structure with integrated lubrication channels and seals, merging multiple functions (guiding, lubrication, sealing) into a single component system. This reduces the need for separate lubrication systems and simplifies the overall device while maintaining reliability through the rigid guide pin structure.
Solution Approach 2:
The patent introduces hydraulic fluid as an intermediary substance that provides lubrication between the guide pins and caliper housing. This mediator reduces friction and wear, enabling smooth caliper motion while maintaining the rigidity and stability of the guide pin structure.
2Device complexity
If brake pad retraction springs are eliminated to simplify the device, then device complexity decreases, but reliability of pad retraction worsens
Solution Approach 1:
The patent replaces the mechanical spring-based retraction system with a hydraulic retraction mechanism. Hydraulic fluid pressure differential (higher pressure on the outboard side during braking) automatically pushes the caliper and brake pads back to the released position, eliminating the need for mechanical retraction springs while maintaining reliable pad retraction.
Solution Approach 2:
The patent uses hydraulic pressure differentials to achieve automatic brake pad retraction. The hydraulic system leverages the same fluid pressure that activates the brakes to also retract them, creating a self-contained retraction mechanism that eliminates mechanical springs and reduces device complexity.
3Device complexity
If guide pins lack lubrication to reduce device complexity, then device complexity decreases, but friction increases causing poor sliding
Solution Approach 1:
The patent introduces hydraulic fluid as a lubricating intermediary between the guide pins and caliper housing. The hydraulic fluid reduces friction and enables smooth sliding motion of the guide pins while being integrated into the existing brake fluid system, avoiding the need for separate lubrication components.
Solution Approach 2:
The hydraulic system serves dual purposes: it both actuates the brake pads and provides lubrication for the guide pins. The same brake fluid that transmits braking force also reduces friction in the guide pin interfaces, allowing the system to self-lubricate without additional complexity.
4Force
If hydraulic axial translation is added to augment braking force, then braking force increases, but device complexity increases
Solution Approach 1:
The patent merges the hydraulic actuation system with the caliper translation mechanism. The hydraulic fluid pressure differential simultaneously acts on the brake pads for braking force and on the caliper housing to provide axial translation motion. This integration augments braking force while avoiding the need for separate translation actuation components.
Solution Approach 2:
The hydraulic system performs multiple functions: it provides braking force through pad actuation, enables caliper axial translation for improved braking geometry, and lubricates guide pins. This multi-functionality augments braking capability while using the existing hydraulic infrastructure, minimizing additional device complexity.
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 ensures reliable and positive motion of the caliper, reduces vibration, and enhances braking force by lubricating guide pins with brake fluid, allowing for larger and more rigid pins, and eliminates the need for retraction springs, while providing efficient pad retraction and reduced natural vibration harmonics.
Implementation Method 1
Fluid pressure translation of the caliper along the pins is achieved by a hydraulic path including a selectively operable hydraulic pressure source, a primary hydraulic cylinder secured to the caliper and closed by a piston, and hydraulic fluid conduits coupling the source to the cylinder
Implementation Method 2
An additional pair of hydraulic cylinders, one formed in each of the housings, and a pair of annular hydraulic seals, each disposed within a hydraulic cylinder about one of the guide pins intermediate the free and bound ends thereof to form a hydraulic seal between a guide pin and the sidewall of the corresponding hydraulic cylinder
Implementation Method 3
This design ensures reliable and positive motion of the caliper, reduces vibration, and enhances braking force by lubricating guide pins with brake fluid
Implementation Method 4
The brake pads are moved inwardly toward one another so as to frictionally engage the opposed sides of the brake rotor. Such frictional engagement causes retarding or stopping of the rotational movement of the brake rotor
Data Source
AI summary
A disc brake having a caliper straddling a rotor; a fixed carrier, an actuator comprising a primary cylinder located in the caliper and closed by a piston; a guide arrangement including first and second pins for allowing the caliper to slide relative to the carrier on actuation, the first and second pins have a bound end fixed to the caliper and a free end respectively retained in first and second bores in the carrier by annular roll-back seals to define first and second auxiliary or secondary hydraulic cylinders. Inboard and outboard friction pads are positioned on opposite faces of the rotor by the piston and the caliper. In operation, the caliper, cylinder, and outboard brake pad are hydraulically moved to engage the outboard brake pad with the rotor while the primary cylinder hydraulically moves the inboard brake pad into engagement with the rotor to effect a brake application.