Braking Device With Centrifugal Elastic Element And Limiting Stop

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Solution Overview

Problem

Existing braking systems for lawn mowers are inefficient in stopping the rotating blades quickly, especially at high speeds and in case of engine overspeeding, and can cause damage to the elastic elements.

Innovation Solution

A brake system with a deformable elastic element that changes configuration based on centrifugal force, featuring a limiting element to prevent over-deformation, ensuring safe and rapid braking by adjusting braking torque in response to engine speed, and maintaining stability through a concave shape and radially extending members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the elastic element is allowed to deform freely under centrifugal force, then the brake release speed range is extended, but the elastic element may be damaged due to excessive deformation

Engineering Contradiction:
Improvebrake release speed rangeVSAvoidelastic element durability
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The limiting element is pre-positioned to define a maximum deformation position for the elastic element before excessive deformation can occur. This preliminary constraint prevents damage while allowing controlled deformation within safe limits during normal operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The limiting element acts as a protective constraint that cushions against excessive centrifugal force effects by physically limiting the elastic element's deformation range, preventing damage before it can occur during high-speed operation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Force

If the brake disc is pressed firmly against the brake friction surface, then braking torque is sufficient at low speeds, but the brake cannot be released quickly at high speeds

Engineering Contradiction:
Improvebraking torqueVSAvoidbrake release speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The elastic element's deformation characteristics dynamically adjust the braking force based on rotational speed. At low speeds, the element maintains firm contact for sufficient braking torque. At high speeds, centrifugal force deforms the elastic element, reducing contact pressure and enabling brake release

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the physical state and deformation parameters of the elastic element in response to speed changes. The elastic element transitions from a loaded state (providing braking torque) to a deformed state (reducing braking force), automatically adapting the braking parameter to operational conditions

Inventive Principle:
Principle #35Parameter changes

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 system effectively stops the blades quickly and prevents damage by adjusting braking torque with engine speed, ensuring safe operation and prolonged component lifespan.

Implementation Method 1

the elastic element being deformable from at least a first configuration into a second configuration when the centrifugal force acting on the elastic element changes from zero to one predetermined level increases

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the biasing force of the elastic element decreases with increasing speed of the motor

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

the deformability of the elastic element is limited in a third configuration by a limiting element, in particular a plate-shaped one, if the centrifugal force acting on the elastic element exceeds a further predetermined level

Methodology Applied
Scientific EffectMechanical constraint:

Implementation Method 4

a first braking surface is brought into frictional contact with a non-rotatable second braking surface by means of the preloaded elastic element and is pressed. This generates a braking torque

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3504954B1Braking device
Publication Date: 2021.08.04 ROBERT BOSCH GMBH
  • EP3504954B1 patent drawingFigure 1
  • EP3504954B1 patent drawingFigure 2
  • EP3504954B1 patent drawingFigure 3~4

AI summary

The invention relates to a brake for a motor (10), comprising an elastic element (20, 20a, 20b, 20c), in particular an elastic element (20) according to one of the preceding claims, wherein the elastic element (20, 20a, 20b, 20c) can rotate with the motor (10) and is deformable from at least a first configuration (1a) to a second configuration (1b) when the centrifugal force acting on the elastic element (20) increases from zero to a predetermined level, whereby the preload force of the elastic element (20) decreases with increasing speed of the motor, the brake is released due to the reduced preload force and the brake then becomes effective again when the centrifugal force acting on the elastic element (20) falls below the predetermined level.It is proposed that the deformability of the elastic element in a third configuration (1c) is limited by a particularly disc-shaped limiting element (30) when the centrifugal force acting on the elastic element (20) exceeds a further predetermined level.