WO2016029928A1

WO2016029928A1 - Cooling system and method for a bicycle disk brake

Info

Publication number: WO2016029928A1
Application number: PCT/EP2014/068026
Authority: WO
Inventors: Torgny Fjeldskaar
Original assignee: Bmc Switzerland Ag
Priority date: 2014-08-26
Filing date: 2014-08-26
Publication date: 2016-03-03

Abstract

Provided is a braking system (10) for a bicycle, said braking system (10) comprises a braking disk (12) and a caliper (16) adapted to operationally engage the braking disk (12) and to release thereof. Said braking system (10) further comprises an air intake system adapted to permit intake of an airflow (18).

Description

COOLING SYSTEM AND METHOD FOR A BICYCLE DISK BRAKE

TECHNICAL FIELD

The present invention is related to a braking system for bicycle, to a method of operating the braking system, to usage thereof, and to a bicycle.

BACKGROUND OF THE INVENTION

Commonly, a braking system for a bicycle comprises a braking disk fixed to a shaft of a bicycle wheel such to rotate integrally therewith. Further comprised is a caliper fixed to portions of the bicycle frame. In this disk brake system, by actuating a brake lever mounted to the handle bar of the bicycle, the user can actuate the caliper or rather the brake pads of the caliper to engage the braking disk. This engagement causes friction between the caliper and the braking disk resulting in a braking action

decelerating the bicycle wheel as a whole. This braking system is provided to the front wheel as well as the rear wheel. The braking system provides braking power in a magnitude relating to the amount of the braking force applied to the brake lever. In a non-braking-situation, i.e. during normal travel, the caliper is in a release position to allow frictionless bicycle wheel rotation. In a braking-situation, heat is generated in the braking system due to friction. The braking disk is made of a material providing maximum mechanical strength in order to assure reliable braking. Common braking disks are made of metal, in particular steel .

The heat generated in the course of braking can cause the braking disk to bend due to thermal extension thereof. This bend or flection of the braking disk can suddenly degrade braking power. Further, friction heat is generated in the brake pads of the caliper resulting in increased slipping which reduces the friction force and therefore tends to degrade braking force. A further disadvantage of increased friction heat generated in the course of braking is in the risk that the braking disk can break resulting in a

dangerous fail of the braking system. Therefore, in order to prevent dangerous degradation or even failure of the braking system for a bicycle, efforts are made in order to overcome friction heat related problems.

One approach is in the provision of cut-outs in the braking disk in order to increase a heat dissipating area as well as to improve venting. These cut-outs can be made of holes arranged in the peripheral region of the braking disk, which region is subjected by the brake pads of the caliper. However, provision of holes delimits mechanical strength of the braking disk. Further, friction is reduced due to decreased area. Conventional technics for heat dissipation in braking systems are limited. Further, aerodynamic properties are degraded.

It is therefore an object of the present invention to alleviate problems in the state of the art as mentioned above. In particular, it is an object of the present invention to provide a braking system which enables secure and reliable braking action. It is further object of the invention to provide a method of operating such a braking system as well as a usage thereof. It is further object of the invention to propose a bicycle comprising such a braking system.

SUMMARY OF THE INVENTION

The present invention is directed to a braking system for a bicycle, said braking system comprises a braking disk and a caliper adapted to operationally engage the braking disk and to release thereof, said braking system further

comprises an air intake system adapted to permit intake of an airflow. The inventive braking system provides superior heat dissipation by way of directing the airflow at least towards the caliper of the braking disk which caliper is heated due to friction force introduced by braking action. It is to be noted that the air intake system can be

comprised in a cover or rather enclosure provided for covering the braking system. In order to allow for heat dissipation, airflow can be guided through the cover and to the covered braking system such to at least impinge on the caliper .

In an embodiment of the proposed braking system the air intake system is adapted to direct said airflow towards at least the caliper, wherein the caliper is arranged for unobstructed reception of said airflow. In order to allow maximum heat dissipation, the caliper is mounted to the bicycle such to allow for unobstructed reception of

airflow. In other words, the airflow or rather magnitude of the airflow reaching the caliper is not delimited,

deteriorated or rather decreased by any obstacle, such as mounting portions of the bicycle, for example a fork leg. Hence, especially heat of the caliper can be dissipated reliable resulting in reduced temperature of the braking system as a whole. Note that the airflow is continuously generated during bicycling and its magnitude is related to the bicycling velocity. High velocity bicycling requires increased braking power in case of the bicycle rider wants to decelerate or even stop the bicycle beginning from said high velocity. Advantageously, increased airflow is present during bicycling with said high velocity.

In an embodiment of the proposed braking system, the caliper is mountable to portions of the bicycle on an upstream side thereof. Therefore, airflow directed to the caliper is increased. In an embodiment of the proposed braking system, the intake system further comprises guiding means adapted to guide the airflow towards at least the caliper for heat dissipation thereof. Hence, heat dissipation is improved by selectively directing the airflow to and along the caliper which caliper requires improved heat dissipation.

In an embodiment of the proposed braking system, the guiding means is further adapted to guide the airflow along at least peripheral portions of the braking disk downstream of the caliper. Such peripheral portions can include the peripheral area of the braking disk which is engaged by brake pads of the caliper during braking. Further, the guiding means can be formed such to permit lamina flow in order to allow maximum flow rate of the air at least across portions of the caliper and/or braking disk.

In an embodiment of the proposed braking system the air intake system is adapted to permit intake of the airflow during breaking and to prevent intake of the airflow otherwise. In this embodiment the braking system is able to permit intake of the airflow in a braking-situation as well as to prevent intake of the airflow in a non-braking situation. Preventing intake of the airflow eliminates aerodynamic drag. Hence, aerodynamic properties are

improved. Note that air intake creates increased

aerodynamic drag. Advantageously, aerodynamic drag can be eliminated due to the inventive airflow intake prevention mechanism during normal travel without braking power application .

In an embodiment of the proposed braking system the air intake system comprises a flap adapted to be opened to permit intake of the airflow and to be closed such to prevent thereof. Therefore, improved braking power

application is enabled due to directed flow of air to and along heated portions of the braking system, in particular the caliper and the braking disk. However, during a non- braking situation or rather normal travel situation, the flap is closed such to eliminate aerodynamic drag. Since no heat dissipation is required during normal travel of the bicycle, the air inflow for heat dissipation is no longer required. Hence, the flap is closed to improve aerodynamic properties of the bicycle as a whole.

In an embodiment of the proposed braking system said flap is adapted to be operated by actuation of a brake lever. Hence, reliable introduction of airflow in a braking- situation as well as reliable prevention of airflow

introduction in a non-braking-situation are obtained. This provides for increased heat dissipation during braking as well as reduced aerodynamic drag during normal travel.

In an embodiment of the proposed braking system, the outside contour of the flap in the closing state is flush with the contour of its surroundings. A braking system is achieved in which landings, interruptions, ledges or any other obstacles or rather resistances to the airflow during normal travel are reduced. Hence, a braking system is obtained showing improved aerodynamic properties.

Proposed is a method of operating a braking system

according to one of claims 1 to 9. Said method comprises directing the airflow towards the caliper such to allow for unobstructed reception of the airflow.

In an embodiment the proposed method of operating a braking system further comprises the steps of: at least in a braking situation, permitting intake of the airflow by means of an air intake system, and directing said airflow such to flow along at least the caliper for heat

dissipation. This method offers a bicycle providing

improved braking power due to increased heat dissipation. Further, this method allows for secure travel of the bicycle in a high velocity.

In an embodiment the proposed method further comprises permitting intake of the airflow in a braking situation, and preventing intake of the airflow otherwise. In addition to improved braking power, the method according to this embodiment further provides improved aerodynamic

properties . In an embodiment the proposed method further comprises the steps of: opening a flap of the air intake system during braking such to permit intake of the airflow, and closing said flap such to be flush with its surroundings otherwise. Hence, a bicycle is obtained having improved heat

dissipation in a braking condition as well as superior aerodynamic properties during travelling.

In an embodiment the proposed method further comprises the step of: controlling a brake lever to actuate the flap such to permit or prevent said intake of airflow. This method provides travelling in a secure and fast manner. Further, the method is performed by simply operating the brake lever as usual without overburden the bicycle rider.

The present invention is further directed to a usage of a braking system according to one of claims 1 to 9 for heat dissipation of at least the caliper of the braking disk.

The present invention is further directed to a bicycle comprising a braking system according to one of claims 1 to 9 adapted to provide for heat dissipation at least in a braking-situation. The proposed bicycle includes a braking system showing superior heat dissipation performance during braking, which provides enduring and reliable braking action . In an embodiment the proposed bicycle is adapted to provide for heat dissipation in the braking-situation and for smooth surfaces in a non-braking-situation. The bicycle according to this embodiment provides improved heat

dissipation performance during braking as well as improved aerodynamic properties during travelling.

It is expressly pointed out that any combination of the above-mentioned embodiment is subject of further possible embodiments. Only those embodiments are excluded that would result in a contradiction.

BRIEF DESCRIPTION OF THE DRAWING

The present invention is further described with reference to the accompanying drawings jointly illustrating various exemplary embodiments, which are to be considered in connection with the following detailed description. What is shown in the Figures is:

Fig. 1: depicts a braking system according to the

invention; and

Figs. 2a, b: depict operational processes of the braking

system according to an embodiment of the invention . Fig. 1 depicts a braking system 10 attached to a rear wheel arrangement in a schematic view. The braking system 10 comprises a braking disk 12 connected to a shaft 14 of the rear wheel (not shown) . The braking disk 12 is mounted to the shaft 14 such to integrally rotate therewith. The braking system 10 further comprises a caliper 16 (shown schematically in solid lines) . The caliper 16 comprises brake pads (not shown) , which can be mechanically or hydraulically actuated such to engage the periphery of the braking disk 12. The friction-based braking generates heat, which has to be dissipated in order to avoid degradation or rather failure of the braking system 10.

Advantageously, the heat is dissipated by an air intake system comprised by the braking system 10. The air intake system permits intake of an airflow 18 (schematically indicated by an arrow) such to be directed towards and across friction-based heated portions of the braking system 10, i.e. in particular towards the caliper 16 as well as portions of the braking disk 12. Further comprised is a cover 20 covering at least portions of the braking system 10. While not shown, the cover 20 can also be disposed to cover a portion of a power train (not shown) , for example a bicycle chain or a drive belt, for transferring power to a sprocket (not shown) affixed to the shaft 14. The air intake system can be part of the cover 20 permitting flow of airflow through the cover 20 into the interior thereof. According to the invention, the air intake system permits intake of the airflow 18, continuously. In an embodiment, the air intake system selectively permits or prevents said intake. The air intake system according to this embodiment comprises a flap 22 pivotally hinged to the cover 20. The flap 22 can be actuated such to provide an opening 24 directed such to permit intake of the airflow 18 to the inside of the cover 20, in a breaking-situation. The airflow 18 is further directed to at least the braking disk 12 and caliper 16 as mentioned above. Hence, proper heat dissipation is achieved.

While not shown, the flap 22 can be actuated such to close the opening 24 and thus to prevent inflow of the airflow 18, in a non-braking-situation. The flap 22 is closed since no heat dissipation is required during normal travel.

Advantageously, by closing the flap 22 the aerodynamic properties of the bicycle are enhanced.

Figs. 2a, b schematically depict the braking system 10, wherein Fig. 2a shows the braking system 10 in a state permitting intake of the airflow (braking-situation) , and Fig. 2b shows the braking system 10 in a state preventing intake of the airflow (non-braking-situation) .

In this illustrative embodiment, the braking system 10 is provided to a front wheel of a bicycle. In the course of braking, the flap 22 of the air intake system is actuated such to provide an opening 24 directed towards the front side (upstream) of the bicycle such to allow intake of airflow. Further, the airflow is directed to portions of the braking disk 12 and the caliper (not shown) in order to selectively dissipate heat. In the opened position, the flap 22 provides aerodynamic drag, which however does not matter in the course of braking.

Subsequently to the braking action to decelerate or stop the bicycle, i.e. during a normal travel situation,

aerodynamic properties have to be considered in order to allow for high velocities. According to the invention, in the course of the normal travel situation, the flap 22 is actuated such to close the opening (refer to Fig. 2a). In this situation, the outer surface of the flap 22 is flush with its surroundings. Therefore, the airflow is not hindered by any obstacles.

In the illustrative embodiment, the flap 22 is hinged to distal end portions of a front wheel fork 26 made of carbon fibers, for example. In the case of the flap 22 is actuated such to prevent inflow of the airflow, as shown in Fig. 2b, the outer surface of the front wheel fork 26 is smooth as a whole. This allows reduced aerodynamic drag. In this embodiment, in order to further decrease aerodynamic drag, the caliper of the braking system 10 is covered by said distal end portion of the front wheel fork 26, too. Hence, a braking system 10 is obtained providing maximum braking power in a reliable and secure manner as well as providing enhanced aerodynamic properties.

Claims

1. A braking system (10) for a bicycle, said braking

system (10) comprises a braking disk (12) and a caliper (16) adapted to operationally engage the braking disk (12) and to release thereof, said braking system (10) further comprises an air intake system adapted to permit intake of an airflow (18) .

2. The braking system (10) according to claim 1, wherein said air intake system is adapted to direct said airflow (18) towards at least the caliper (16), wherein said caliper (16) is arranged for unobstructed reception of said airflow (18) .

3. The braking system (10) according to claim 1 or 2,

wherein said caliper (16) is mountable to portions of the bicycle on an upstream side thereof.

4. The braking system (10) according to one of the

preceding claims, said intake system comprises guiding means adapted to guide the airflow (18) towards at least the caliper (16) for heat dissipation thereof.

5. The braking system (10) according to claim 4, wherein said guiding means is further adapted to guide the airflow (18) along at least peripheral portions of the braking disk (12) downstream of the caliper (16).

6. The braking system (10) according to one of the

preceding claims, wherein the air intake system is adapted to permit intake of the airflow (18) during breaking and to prevent intake of the airflow (18) otherwise .

7. The braking system (10) according to claim 6, wherein the air intake system comprises a flap (22) adapted to be opened to permit intake of the airflow (18) and to be closed such to prevent thereof.

8. The braking system (10) according to claim 7, wherein the flap (22) is adapted to be operated by actuation of a brake lever.

9. The braking system (10) according to claim 7 or 8,

wherein the outside contour of the flap (22) in the closing state is flush with the contour of its

surroundings .

10. A method of operating a braking system (10) according to one of claims 1 to 9, comprising directing the airflow (18) towards the caliper (16) such to allow for unobstructed reception of the airflow (18) .

11. The method of operating a braking system (10)

according to claim 10, comprising: at least in a braking situation, permitting intake of the airflow (18) by means of an air intake system, and directing said airflow (18) such to flow along at least the caliper (16) for heat dissipation.

12. The method according to claim 11, further comprising: permitting intake of the airflow (18) in a braking- situation; and preventing intake of the airflow (18) otherwise.

13. The method according to claim 11 or 12, further

comprising : opening a flap (22) of the air intake system during braking such to permit intake of the airflow (18), and closing said flap (22) such to be flush with its surroundings otherwise.

14. The method according to claim 13, comprising: controlling a brake lever to actuate the flap (22) such to permit or prevent said intake of airflow (18). Usage of a braking system (10) according to one claims 1 to 9 for heat dissipation of at least caliper (16) of the braking disk (12) .

A bicycle comprising a braking system (10) according to one of claims 1 to 9, adapted to provide for heat dissipation at least in a braking-situation.

The bicycle according to claim 16, adapted to provide for heat dissipation in the braking-situation and for smooth surfaces in a non-braking-situation.