GB2589152A

GB2589152A - Braking device and braking system

Info

Publication number: GB2589152A
Application number: GB1917148.7A
Authority: GB
Inventors: Frederick Wardle Derek
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-11-25
Filing date: 2019-11-25
Publication date: 2021-05-26
Also published as: GB201917148D0

Abstract

A braking device 100, for a vehicle, comprises a housing 110, a rotor 120 within the housing 110, and braking means 130 for, during braking, selectively changing, independent of an angular speed of the rotor 120, a viscosity of a non-Newtonian fluid 200 sealed within the housing 110 through which the rotor 120 moves when rotating during braking. The braking means 130 comprises a plunger which moves in and out of a cavity (300, fig 3A) thereby changing a volume of the cavity (300). Reducing the volume of the cavity (300) increases the viscosity of the non-Newtonian fluid, e.g. shear thickening fluid 200, which applies a braking force to the rotor 120 that is connected to a drive shaft/axle of the vehicle. Reference is also made to a braking system wherein the braking means 130 is moved by a braking command means (410) which may comprise a hydraulic system or electric motor connected to, for example, a brake pedal.

Description

TITLE

Braking Device and Braking System

TECHNOLOGICAL FIELD

Embodiments of the present disclosure relate to a braking device and a braking system. Some relate to a braking device and a braking system in an automotive vehicle.

BACKGROUND

Traditional braking systems use pads and discs and/or shoes and drums to apply braking forces to wheels of a vehicle. The disadvantage of these traditional braking systems is that they wear out and require replacement one or more times during the lifetime of the vehicle.

BRIEF SUMMARY

According to various, but not necessarily all, embodiments there is provided a braking device comprising: a housing; a rotor within the housing; braking means for, during braking, selectively changing, independent of the angular speed of the rotor, a viscosity of a non-Newtonian fluid, sealed within the housing, through which at least part of the rotor moves through when rotating during braking.

In some, but not necessarily all examples, the braking means is configured to change the volume of a cavity defined between the inner surface of the housing and the rotor to control the viscosity of the non-Newtonian fluid.

In some, but not necessarily all examples, the cavity is the space between the inner surface of the housing and the outer surface of the rotor. The cavity may be filled with a mixture of the non-Newtonian fluid and air/gas.

In some, but not necessarily all examples the braking means comprises a plunger, wherein the plunger is configured to move within the housing to change the volume of the cavity.

In some, but not necessarily all examples, the braking means is configured to be activatable and de-activatable independent of the angular speed of the rotor.

In some, but not necessarily all examples, the braking means is separate to the rotor.

In some, but not necessarily all examples, the non-Newtonian fluid is a shear thickening fluid.

In some, but not necessarily all examples, the braking means changes at least a parameter of a plurality of parameters on which the viscosity of the non-Newtonian fluid depends In some, but not necessarily all examples, the braking means is configured to conned to a hydraulic system connectable to a brake pedal, wherein the braking means is configured to change the viscosity of the non-Newtonian fluid in response to actuation of the brake pedal.

In some, but not necessarily all examples, the braking means is configured to conned to an electric motor, wherein the braking means is configured to be moved by the electric motor to change the viscosity of the non-Newtonian fluid.

In some, but not necessarily all examples, the braking means is configured to increase the viscosity of the non-Newtonian fluid to such an extent so as to solidify at least part of the non-Newtonian fluid.

In some, but not necessarily all examples, an internal surface of the housing configured to be exposed to the non-Newtonian fluid is coated with Polytetrafluoroethylene.

In some, but not necessarily all examples, a surface of the braking means configured to be exposed to the non-Newtonian fluid is coated with Polytetrafluoroethylene.

In some, but not necessarily all examples, the rotor is configured to connect to a drive shaft of a vehicle.

In some, but not necessarily all examples, the rotor is configured to connect to an axle of a vehicle.

In some, but not necessarily all examples, the braking means is configured to force the non-Newtonian fluid into the rotational path of the rotor to increase resistance against the rotation of the rotor.

According to various, but not necessarily all, embodiments there is provided a braking system comprising: a braking device; braking command means; wherein the braking device comprises: a housing; a rotor within the housing; braking means for, when braking, selectively changing, independent of the angular speed of the rotor, a viscosity of a non-Newtonian fluid, sealed within the housing, through which at least part of the rotor moves through when rotating during braking; wherein the braking command means is configured to command the braking means to change the viscosity of the non-Newtonian fluid.

In some, but not necessarily all examples the braking command means comprises a hydraulic system connected to a brake pedal, wherein the braking means is configured to change the viscosity of the non-Newtonian fluid in response to actuation of the brake pedal.

In some, but not necessarily all examples the braking command means comprises an electric motor connected to a controller, wherein the electric motor is configured to be actuated in response to a command from the controller, wherein the electric motor is configured to connect to the braking means, wherein the braking means is configured to be moved by the electric motor to change the viscosity of the non-Newtonian fluid.

According to various, but not necessarily all, embodiments there is provided a vehicle comprising the braking system and/or braking device as referred to above.

According to various, but not necessarily all, embodiments there is provided a braking device comprising: a housing; a rotor within the housing; braking means for selectively changing, independent of the angular speed of the rotor, a viscosity of a non-Newtonian fluid sealed within the housing through which at least part of the rotor moves through when rotating.

According to various, but not necessarily all, embodiments there is provided examples as claimed in the appended claims.

BRIEF DESCRIPTION

Some examples will now be described with reference to the accompanying drawings in which: FIG. 1 shows an example embodiment of the subject matter disclosed herein; FIG. 2 shows an example embodiment of the subject matter disclosed herein; FIG. 3A shows an example embodiment of the subject matter disclosed herein; FIG. 3B shows an example embodiment of the subject matter disclosed herein; FIG. 3C shows an example embodiment of the subject matter disclosed herein; FIG. 4 shows an example embodiment of the subject matter disclosed herein; FIG. 5 shows an example embodiment of the subject matter disclosed herein.

DETAILED DESCRIPTION

FIG. 1 illustrates a cross section of an example braking device 100 comprising a housing 110, a rotor 120 within the housing 110, and braking means 130 for, during braking, selectively changing, independent of the angular speed of the rotor 120, a viscosity of a non-Newtonian fluid 200 sealed within the housing 110 through which at least part of the rotor 120 moves through when rotating during braking. Throughout the examples illustrated herein, reference to selectively changing, independent of the angular speed of the rotor 120, a viscosity of the non-Newtonian fluid 200 means that the braking means 130 can selectively change the viscosity of the non-Newtonian fluid regardless of the motion and angular speed of the rotor 120. The rotor 120 itself may have an effect on the viscosity of the non-Newtonian fluid 200 due to its speed whilst rotating. The braking means 130 provides means for increasing or decreasing the viscosity of the non-Newtonian fluid 200 independent of the speed of the rotor 120.

It is not a change in rotor speed that causes the selective change of the viscosity but the braking means 130.

Throughout the examples illustrated, a non-Newtonian fluid 200 refers to a fluid which does not obey Newton's laws of viscosity. In some, but not necessarily all, examples, a shear thickening fluid (STF) may be used which is a type of non-Newtonian fluid.

Shear thickening fluids are also referred to as dilatant fluids. In some, but not necessarily all, examples, the STF is a mixture of corn starch and water, which is referred to as oobleck. In some, but not necessarily all, examples, the STF is silica nano-particles dispersed in a solution of polyethylene glycol.

FIG. 2 illustrates a cross section of an example braking device 100 which is the same as the braking device 100 shown in FIG. 1, except that FIG. 2 illustrates the braking device 100 with the non-Newtonian fluid 200 within the housing 110. As shown in FIG. 2, the non-Newtonian fluid 200 fills the housing interior to such an extent that at least part of the rotor 120 moves through the non-Newtonian fluid 200 when the rotor 120 rotates. In FIG. 2 the remaining volume of the interior of the housing 110 is filled with air 210 FIG. 3A illustrates a cross section of an example braking device 100 which is the same as the braking device 100 illustrated in FIGS. 1 and 2. In FIG. 3A the braking means has been moved to change the viscosity of the non-Newtonian fluid 200 during braking. In FIG. 3A, the height of the non-Newtonian fluid within the housing 110 is shown higher than in FIG. 2 for illustration purposes to show how the movement of the braking means 130 interrupts the movement of the non-Newtonian fluid around the housing. The amount of non-Newtonian fluid 200 that is sealed within the housing is variable. In this example, the amount of non-Newtonian fluid within the housing is such that when the rotor rotates there is a flow of non-Newtonian fluid 200 around the housing which can be interrupted by movement of the braking means 130.

In FIG. 3A the braking means 130 is configured to change the volume of a cavity 300. The cavity 300 is defined as the volume between the inner surface of the housing 110 and the outer surface of the rotor 120 and may be filled by a combination of non-Newtonian fluid 200 and air or another gas 210. In FIG. 3A the movement of the braking means 130 into the cavity 300 reduces the volume of the cavity 300 and causes interference to the movement of the non-Newtonian fluid 200 around the housing 110, thereby increasing the viscosity of the non-Newtonian fluid.

In the example of FIG. 3A the braking means 130 comprises a plunger. The plunger is configured to move within the housing 110 to change the volume of the cavity 300.

The braking means 130 is configured to be activatable and to be de-acfivatable independent of the angular speed of the rotor 120, as the speed of the rotor 120 does not affect the selective operation of the braking means 130. The movement of the braking means 130 within the housing 110 is also independent of the angular speed of the rotor 120. In the examples of FIGS. 1 to 30 the braking means 130 is separate to the rotor 120, as the braking means 130 does not form part of the rotor 120.

In the example of FIG. 3A the non-Newtonian fluid 200 is a shear thickening fluid. When the braking means 130 moves within the housing 110 to reduce the volume of the cavity 300, this creates an interference to the movement by reducing the volume of the sealed enclosure of the housing 110. This interference creates a shear force within the shear thickening fluid by displacement of the braking means 130. The viscosity of the shear thickening fluid gradually increases when subjected to gradual sheer loading and, under shock loads, becomes a solid mass within milliseconds. The increase in viscosity of the shear thickening fluid provides increased resistance against the rotating of the rotor, thereby providing a braking effect. When the load caused by the braking means 130 is removed the shear thickening fluid returns to its previous liquid state. In situations where the braking means 130 are engaged suddenly and fully by the user, the quickness and strength of the impact causes the non-Newtonian fluid to solidify. This will cause the rotor to slow down very quickly, as the solid mass will suddenly decrease the angular speed of the rotor.

In the example of FIG. 3A the braking means 130 changes at least one parameter of a plurality of parameters on which the viscosity of the non-Newtonian fluid 200 depends. For example, the surface of the interior of the housing 110 and the surface of the rotor 120 will affect the viscosity of the non-Newtonian fluid 200, as well as the speed of the rotor.

FIG. 3B illustrates a cross section of an example braking device 100. In this example, the volume of non-Newtonian Fluid 200 is such that the remaining volume of the sealed housing is filled with air or another gas with a volume that matches the total volume of the gaps 121 between the teeth 122 of the rotor 120. In the example of FIG. 3B the pressure of the air or other gas is at atmospheric pressure or thereabouts when it's volume matches the volume of the gaps 121. The volume of the gaps 121 is defined as the difference in volume between the rotor 120 and the volume of the rotor 120 if it was circular around its edge in cross section without gaps 121. When the rotor 120 spins, the centrifugal force caused by the angular speed of the rotor 120 will eject the non-Newtonian fluid 200 from the gaps 121, leaving the gaps occupied by mainly air or gas, as illustrated in FIG. 3B. This creates less resistance for the rotation of the rotor, and so when it is not intended for the rotor to be braked, this allows for the rotor to spin with less resistance.

FIG. 30 illustrates a cross section of the same example braking device in FIG. 3B, with the braking means 130 engaged during braking. As the braking means 130 decreases the volume of the sealed housing when it is engaged during braking, this causes compression of the air or gas 210 within the sealed housing, as the non-Newtonian fluid 200 is less compressible than the gas 210 due it being a liquid/solid. The gas 210 occupies less volume due to it being compressed compared to when the braking means 130 is less engaged/not engaged. This will cause the non-Newtonian fluid 200 to enter the gaps 121 as the volume of the gas 210 before it was compressed matches the volume of the gaps 121. This results in an increased contact area between the rotor 120 and the non-Newtonian fluid 200. The impact of the non-Newtonian fluid 200 on the rotor 200 as it enters the gaps 210 causes the non-Newtonian fluid 200 to increase in viscosity. The non-Newtonian fluid 200 entering the gaps 121 and increasing in viscosity causes increased resistance for the rotation of the rotor 120, causing it to slow down.

In FIG. 30 the movement of the non-Newtonian fluid 200 into the gaps 121 has caused most of the gas 210 to be displaced out of the gaps 121 so that the gaps 121 are mainly filled with the non-Newtonian fluid 200. In some examples, all of the gas 210 exits the gaps 121. Filling the gaps 121 mainly or entirely with the non-Newtonian fluid 200 will cause the rotor 120 to slow down significantly from a high angular speed, as the impact of the rotor 120 on the non-Newtonian fluid 200 will cause the non-Newtonian fluid 200 to increase in viscosity. In situations where the braking means 130 are engaged suddenly and fully by the user, the quickness and strength of the impact causes the non-Newtonian fluid to solidify. Due to the non-Newtonian fluid 200 being forced into the gaps 121 and becoming solid this will cause a sudden decrease in the angular speed of the rotor 120.

When the non-Newtonian fluid 200 is ejected from the gaps 121 the force of this will cause the non-Newtonian fluid 200 that is ejected to increase in viscosity. Non-Newtonian fluid 200 which is not near the rotor 120 but is around the periphery of the housing will be less viscous as it will not have been in contact with the rotor 120 for some time. This means it will be easier for the braking means 130 to initially enter the interior of the housing 110 as it enters from the periphery of the housing 110. This will provide an easy way for the non-Newtonian fluid 200 to enter the gaps 121 in an emergency stop situation as it will be easy for the braking means 130 to push the non-Newtonian fluid into the gaps 121.

In the examples of FIG. 1 to FIG. 30 the internal surface of the housing 110 that is configured to be exposed to the non-Newtonian fluid 200 is coated with Polytetrafluoroethylene or a similar material. The Polytetrafluoroethylene or similar material may be partly bonded to allow for easy replacement. The surface of the braking means 130 configured to be exposed to the non-Newtonian fluid 200 is also coated with Polytetrafluoroethylene or a similar material and may also be partly bonded to allow for easy replacement.

FIG. 4 illustrates an example braking system 400. The braking system 400 comprises a braking device 100 and braking command means 410. In this example the braking device 100 is the same as the braking device illustrated in FIGS. 1 to 30. The braking command means 410 is configured to command the braking means 130 of the braking device 100 to change the viscosity of the non-Newtonian fluid 200 during braking.

FIG. 5 illustrates an example braking system 400. In this example the braking command means 410 comprises a hydraulic system connectable to a brake pedal.

The braking means 130 is configured to change the viscosity of the non-Newtonian fluid 200 in response to actuation of the brake pedal. Actuation of the brake pedal causes a change in pressure in the oil within the oil line 411 which causes an actuator piston 412 to move during braking. The actuator piston 412 is connected to the braking means 130 which causes movement of the braking means 130.

FIG. 5 also illustrates the braking device 110 connected to a drive shaft 500 of a vehicle. The drive shaft 500 is connected to a bearing housing 510 containing bearings which transfer the rotational motion of the drive shaft to the rotor 120 within the braking device 100. FIG. 5 also illustrates side plates 111 and 112 which complete the sealing of the housing of the braking device 100. In FIGS. 1 to 3C the side plates 111 and 112 are not shown so as to illustrate the interior of the housing 110 in cross section.

In another example the braking command means 410 comprises an electric motor connected to a controller. The electric motor is configured to be actuated in response to a command from the controller. The electric motor is configured to connect to the braking means 130 which is configured to be moved by the electric motor to change the viscosity of the non-Newtonian fluid 200.

When the vehicle has come to a stop, the rotor 120 will have stopped spinning and the braking means 130 will no longer be moving. As less force is being applied to the non-Newtonian fluid 200 in this situation, it will revert to being less viscous and so won't be able to keep the vehicle stationary. For example if the vehicle is on a slope, the wheels would begin to rotate due to gravity if the vehicle were to rely on only the braking device 100 to keep the vehicle stationary. The rotor 120 would rotate as the non-Newtonian fluid 200 will be less viscous. So that the vehicle can be kept stationary, the vehicle may comprise an electronic parking brake and/or disk wheel brake and/or transmission park mode which can keep the vehicle stationary after the braking device 100 has slowed/stopped the vehicle. In some examples the electronic parking brake and/or disk wheel brake and/or transmission park mode is activated when the vehicle is stationary and remains engaged until manually disengaged. In some examples the activation of the electronic parking brake and/or disk wheel brake and/or transmission park mode when the vehicle is stationary is automatic.

Throughout the examples illustrated the braking means 130 comprises a plunger. In other examples multiple plungers may be present, which may be spaced equally around the circumference if there is an odd number, or directly opposite each other if there is an even number. In other examples, other alternative means instead of plungers for changing the volume of the housing 110 may be used. For example, a sidewall of the housing may be moved to change the volume of the housing 110.

The profile of the rotor 120 is not limited to the profile shown in the figures. Any suitable profile may be used.

In other examples, part of the rotor 120 is moveable to create the braking means 130. For example, moveable flaps may be provided on the rotor 120 which when moved change the volume of the housing 110 and cause interference within the non-Newtonian fluid 200.

The term 'comprise' is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising Y indicates that X may comprise only one Y or may comprise more than one Y. If it is intended to use comprise' with an exclusive meaning then it will be made clear in the context by referring to "comprising only one.." or by using "consisting".

In this description, reference has been made to various examples. The description of features or functions in relation to an example indicates that those features or functions are present in that example. The use of the term 'example' or 'for example' or can' or may' in the text denotes, whether explicitly stated or not, that such features or functions are present in at least the described example, whether described as an example or not, and that they can be, but are not necessarily, present in some of or all other examples. Thus 'example', 'for example', 'can' or 'may' refers to a particular instance in a class of examples. A property of the instance can be a property of only that instance or a property of the class or a property of a sub-class of the class that includes some but not all of the instances in the class. It is therefore implicitly disclosed that a feature described with reference to one example but not with reference to another example, can where possible be used in that other example as part of a working combination but does not necessarily have to be used in that other example.

Although examples have been described in the preceding paragraphs with reference to various examples, it should be appreciated that modifications to the examples given can be made without departing from the scope of the claims.

Features described in the preceding description may be used in combinations other than the combinations explicitly described above.

Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not.

Although features have been described with reference to certain examples, those features may also be present in other examples whether described or not.

The term 'a' or 'the' is used in this document with an inclusive not an exclusive meaning. That is any reference to X comprising a/the Y indicates that X may comprise only one Y or may comprise more than one Y unless the context clearly indicates the contrary. If it is intended to use 'a' or 'the' with an exclusive meaning then it will be made clear in the context. In some circumstances the use of 'at least one' or 'one or more' may be used to emphasis an inclusive meaning but the absence of these terms should not be taken to infer an exclusive meaning.

The presence of a feature (or combination of features) in a claim is a reference to that feature or (combination of features) itself and also to features that achieve substantially the same technical effect (equivalent features). The equivalent features include, for example, features that are variants and achieve substantially the same result in substantially the same way. The equivalent features include, for example, features that perform substantially the same function, in substantially the same way to achieve substantially the same result.

In this description, reference has been made to various examples using adjectives or adjectival phrases to describe characteristics of the examples. Such a description of a characteristic in relation to an example indicates that the characteristic is present in some examples exactly as described and is present in other examples substantially as described.

Whilst endeavoring in the foregoing specification to draw attention to those features believed to be of importance it should be understood that the Applicant may seek protection via the claims in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not emphasis has been placed thereon.

I/we claim:

Claims

CLAIMS1. A braking device comprising: a housing; a rotor within the housing; braking means for, during braking. selectively changing, independent of the angular speed of the rotor, a viscosity of a non-Newtonian fluid, sealed within the housing, through which at least part of the rotor moves through when rotating during braking.
2. A braking device as claimed in any preceding claim, wherein the braking means is configured to change the volume of a cavity defined between the inner surface of the housing and the rotor to control the viscosity of the non-Newtonian fluid.
3. A braking device as claimed in claim 2, wherein the braking means comprises a plunger, wherein the plunger is configured to move within the housing to change the volume of the cavity.
4. A braking device as claimed in any preceding claim, wherein the braking means is configured to be activatable and de-activatable independent of the angular speed of the rotor.
5. A braking device as claimed in any preceding claim, wherein the braking means is separate to the rotor.
6. A braking device as claimed in any preceding claim, wherein the non-Newtonian fluid is a shear thickening fluid.
7. A braking device as claimed in any preceding claim, wherein the braking means changes at least a parameter of a plurality of parameters on which the viscosity of the non-Newtonian fluid depends.
8. A braking device as claimed in any preceding claim, wherein the braking means is configured to connect to a hydraulic system connectable to a brake pedal, wherein the braking means is configured to change the viscosity of the non-Newtonian fluid in response to actuation of the brake pedal.
9. A braking device as claimed in any of claims 1 to 8, wherein the braking means is configured to connect to an electric motor, wherein the braking means is configured to be moved by the electric motor to change the viscosity of the non-Newtonian fluid.
10. A braking device as claimed in any preceding claim, wherein the braking means is configured to increase the viscosity of the non-Newtonian fluid to such an extent so as to solidify at least part of the non-Newtonian fluid.
11 A braking device as claimed in any preceding claim, wherein an internal surface of the housing configured to be exposed to the non-Newtonian fluid is coated with Po lytetrafl uo roethyle ne.
12. A braking device as claimed in any preceding claim, wherein a surface of the braking means configured to be exposed to the non-Newtonian fluid is coated with Po lytetrafl uo roethyle ne.
13. A braking device as claimed in any preceding claim, wherein the rotor is configured to connect to a drive shaft of a vehicle.
14. A braking device as claimed in any preceding claim, wherein the rotor is configured to connect to an axle of a vehicle.
15. A braking device as claimed in any preceding claim, wherein the braking means is configured to force the non-Newtonian fluid into the rotational path of the rotor to increase resistance against the rotation of the rotor.
16. A braking system comprising: a braking device; braking command means; wherein the braking device comprises: a housing; a rotor within the housing; braking means for, when braking, selectively changing, independent of the angular speed of the rotor, a viscosity of a non-Newtonian fluid, sealed within the housing, through which at least part of the rotor moves through when rotating during braking; wherein the braking command means is configured to command the braking means to change the viscosity of the non-Newtonian fluid.
17. A braking system as claimed in claim 16, wherein the braking command means comprises a hydraulic system connected to a brake pedal, wherein the braking means is configured to change the viscosity of the non-Newtonian fluid in response to actuation of the brake pedal.
18. A braking system as claimed in claim 16, wherein the braking command means comprises an electric motor connected to a controller, wherein the electric motor is configured to be actuated in response to a command from the controller, wherein the electric motor is configured to connect to the braking means, wherein the braking means is configured to be moved by the electric motor to change the viscosity of the non-Newtonian fluid.
19. A vehicle comprising the braking system as claimed in any of claims 16 to 18.