Patent Description:
<CIT> provides for an anti-lock braking system for a single-track vehicle with a clutch for temporarily disengaging a hub of a wheel of the single-track vehicle from a brake of the single-track vehicle. However, although the anti-lock braking system design shown in <CIT> works very well over a broad range of usage scenarios, there may be circumstances under which modified versions may yield even superior performance.

According to the present invention, an anti-lock braking system for a vehicle may comprise a hub with a hollow cavity which is configured to accommodate an axle, a device with a first part that is substantially static relative to the hub and a second part that may rotate relative to the hub when the first part and the second part are disengaged, and an actuator which is configured to control a transmission of a braking force from a frame of the vehicle to the hub by actuating the device, wherein one of the first part and the second part is configured to extend helically around the axle.

In this regard, the term "anti-lock braking system", as used throughout the description and the claims, particularly refers to a braking system which is configured to monitor sensor measurements indicating whether the vehicle is about to lose traction while braking and to temporarily decrease a braking force until traction is restored. Moreover, the term "hub", as used throughout the description and the claims, particularly refers to a component which has an outer surface that is (substantially) axially symmetric to the axle, wherein a tire of a wheel which comprises the hub is connected to the hub by one or more members (e.g., spokes) extending substantially radially outward from the outer surface.

Furthermore, the term "axle", as used throughout the description and the claims, particularly refers to an elongated component to which the hub is connected by a bearing (e.g., a ball bearing). Moreover, the term "actuator", as used throughout the description and the claims, particularly refers to an electric device which allows exerting a force onto an element to position of the element. , the element may move from a first position to a second position when the actuator exerts a force onto the element. The element may return to the first position when the actuator ceases to exert the force onto the element. Furthermore, the term "frame", as used throughout the description and the claims, particularly refers to a rigid structure which provides a support for persons or goods transported by the vehicle. For example, the term "frame", as used throughout the description and the claims, may refer to a frame of a bicycle. In addition, the formulation "actuating the device", as used throughout the description and the claims, particularly refers to causing the first part and the second part to engage or disengage. The part that extends helically around the axle may provide for superior traction between the hub and the frame when the brake is activated to decelerate the vehicle.

The invention may further comprise a torsion spring. The torsion spring may be configured to cause the first part and the second part to engage when the actuator is deactivated.

This may reduce the energy consumption of the anti-lock braking system and improve safety. For example, the actuator may only be activated (for relative short amounts of time) when sensor measurements indicate that the vehicle is about to lose traction while braking.

The device may be a band clutch, a wrap spring clutch, etc..

Band clutches and spring clutches allow for safely transmitting high braking forces (torques). In addition, a torque transmitted through a band clutch, or a spring clutch can be accurately controlled using sensors required for establishing the anti-lock braking functionality of the system.

The anti-lock braking system according to the invention may further comprise a disc of a disc brake.

A disc brake allows for increasing the maximum braking force while at the same time allowing for accurate manual control of the barking torque.

The first part may be configured to extend helically around the axle and the second part may comprise a cylindrical portion, wherein the disc may be connected to, attached to, or integrally formed with, said cylindrical portion. The anti-lock braking system may further comprise a first element, a second element, and a torsion spring. The torsion spring may be connected to the first part by the first element. The second element may be configured to be movable by the actuator and the second element may cause the first element to rotate relative to the hub around the axle when the second element is moved parallel to a longitudinal axis of the axle. The second element may comprise a magnetic material and the actuator may be configured to generate a magnetic field when activated. The actuator may comprise an electromagnet which is substantially static relative to the axle.

This provides for a fast response time and low wear and tear.

Alternatively, the second part may be configured to extend helically around the axle and the disc may be connected to, attached to, or integrally formed with, said second part. The first part may comprise a cylindrical portion and the second part may be configured to extend helically around the cylindrical portion.

The anti-lock braking system according to the invention may further comprise a generator.

The generator may comprise a first portion which is substantially static relative to the axle and a second portion which is substantially static relative to the hub. The first portion may have a power output.

This may allow to provide power to all frame-mounted components and thus obviate the need for batteries.

The anti-lock braking system according to the invention may further comprise a lighting. The generator may be configured to provide electric energy to power the lighting through the power output.

The anti-lock braking system according to the invention may further comprise an inertial measurement unit. The inertial measurement unit may be mounted on the axle. The generator may be configured to provide electric energy to power the inertial measurement unit through the power output.

In this regard, the term "inertial measurement unit", as used throughout the description and the claims, particularly refers to a unit which comprises one or more accelerometers and/or gyroscopes. If the inertial measurement unit comprises more than one accelerometer, the accelerometers might measure acceleration in perpendicular directions (e.g., x-, y-, and z-directions in a Cartesian coordinate system). If the inertial measurement unit comprises more than one gyroscope, the gyroscopes might measure rotational rates around perpendicular axes (e.g., roll, pitch, yaw). Moreover, the formulation that a component is "mounted on the axle", as used throughout the description and the claims, particularly refers to a component which is attached to the axle such that the component remains substantially static relative to the axle. That the inertial measurement unit remains substantially static relative to the axle may be beneficial in obviating the need for transforming measurements from a hub-centric coordinate system to a frame-centric coordinate system.

The inertial measurement unit may be configured to measure a yaw rate of the vehicle.

The anti-lock braking system according to the invention may further comprise an angular rate sensor. The angular rate sensor may be configured to measure an angular rate of the hub. The generator may be configured to provide electric energy to power the angular rate sensor through the power output.

The anti-lock braking system according to the invention may further comprise a controller.

The controller may be mounted on the axle. The controller may be configured to determine, based on measurements of the inertial measurement unit and/or the angular rate sensor whether the braking force exerted on the hub is to be reduced to prevent the wheel from locking up. The controller may be further configured to cause a reduction in the braking force exerted on the hub by activating the actuator. The controller may comprise a processor and a memory storing instructions which when executed by the processor cause the processor to determine whether the braking force exerted on the hub is to be reduced and to activate the actuator if the braking force exerted on the hub is to be reduced.

The anti-lock braking system according to the invention may be an anti-lock braking system for a single-track vehicle.

In this regard, the term "single-track vehicle", as used throughout the description and the claims, particularly refers to a vehicle that leaves a single ground track as it moves along a straight line.

The foregoing aspects and many of the attendant advantages will become more readily appreciated as the same become better understood by reference to the following description of embodiments, when taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts throughout the various views, unless otherwise specified.

Notably, the drawings are not necessarily drawn to scale and unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

<FIG> illustrates anti-lock braking system <NUM>. Anti-lock braking system <NUM> comprises hub <NUM> having hollow cavity <NUM>. Hollow cavity <NUM> accommodates axle <NUM> to which hub <NUM> is connected by a ball bearing. Anti-lock braking system <NUM> further comprises device <NUM> having first part <NUM> and second part <NUM> which form a clutch (e.g., a band clutch, a wrap spring clutch, etc.). First part <NUM> is integrally formed with hub <NUM>. Second part <NUM> is connected to disc <NUM> of disc brake <NUM> by cylindrical portion <NUM> and may rotate relative to hub <NUM> around the longitudinal axis A of axle <NUM> when first part <NUM> and second part <NUM> are disengaged. One side of cylindrical portion <NUM> dives into a ring-shaped opening in hub <NUM>. Anti-lock braking system <NUM> further comprises actuator <NUM>. Actuator <NUM> may control the transmission of the braking force from disc brake <NUM> (which may be mounted on the frame of the vehicle) to hub <NUM> by actuating device <NUM>. When actuator <NUM> actuates device <NUM>, second part <NUM> which extends helically around axle <NUM> starts rotating relative to hub <NUM>. This allows for temporarily reducing the braking torque which is exerted by disc brake <NUM> on a wheel that is connected to hub <NUM> by spokes or other means.

<FIG> shows a modified anti-lock braking system <NUM> where controller <NUM> and inertial measurement unit <NUM> are integrated into hub <NUM> and mounted on axle <NUM>. Controller <NUM> is configured to determine, based on measurements of inertial measurement unit <NUM> (which measures a yaw rate of the vehicle) and angular rate sensor <NUM> (which measures an angular rate of hub <NUM> around axis A) whether the braking force exerted on hub <NUM> is to be reduced to prevent a wheel comprising hub <NUM> from locking up. If controller <NUM> determines that the braking force exerted on hub <NUM> is to be reduced, controller <NUM> activates actuator <NUM> to (temporarily) disengage first part <NUM> and second part <NUM>. Controller <NUM> is further configured to monitor a response of the vehicle to the activation of the actuator <NUM> and adjust an operation of the clutch (i.e., decrease or increase a friction between first part <NUM> and second part <NUM>) as deemed necessary or beneficial for stabilizing a motion of the vehicle. Once the motion of the vehicle has been stabilized, controller <NUM> may deactivate actuator <NUM>. This may cause first part <NUM> and second part <NUM> to (re-)engage.

The electric energy required by actuator <NUM>, controller <NUM>, inertial measurement unit <NUM>, and angular rate sensor <NUM> is provided by generator <NUM>. Generator <NUM> comprises first portion 38a which is substantially static relative to axle <NUM> and second portion 38b which is substantially static relative to hub <NUM>, wherein the power output of generator <NUM> is comprised in first part 38a. If the vehicle comprises a lighting, generator <NUM> may also provide electric energy to the lighting. Anti-lock braking system <NUM> further comprises an energy storage (which may be integrated in the first part 38a of generator <NUM> or controller <NUM>) and the electric devices may be supplied with electric energy from the energy storage. The energy storage may be used to continuously power a subset of the electric devices (such as the lighting) or as a backup energy source if (another part of) generator <NUM> fails. Alternatively, all power generated by the (other parts of) generator <NUM> may be supplied to the energy storage which may then provide the energy to power (all) the electric devices of the vehicle.

<FIG> illustrates an anti-lock braking system <NUM> for a vehicle which differs from the anti-lock braking system <NUM> shown in <FIG> in that the first part <NUM> extends helically around axle <NUM> and in that the second part <NUM> comprises the cylindrical portion <NUM>, wherein the disc <NUM> is integrally formed with the cylindrical portion <NUM>. As illustrated by <FIG>, the same modifications that may be made to the anti-lock braking system <NUM> of <FIG> (as illustrated by <FIG>) may also be applied to the anti-lock braking system <NUM> of <FIG>.

<FIG> illustrates an anti-lock braking system <NUM> which differs from the anti-lock braking system <NUM> shown in <FIG> in that the anti-lock braking system <NUM> shown in <FIG> comprises torsion spring <NUM> which causes first part <NUM> and second part <NUM> to engage when actuator <NUM> is deactivated. Torsion spring <NUM> is connected to first part <NUM> by first element <NUM>. When actuator <NUM> (which may comprise an electromagnet) is activated, second element <NUM> (which may comprise a magnetic material) is moved parallel to axis A towards actuator <NUM>. As second element <NUM> is connected to hub <NUM> by a linear bearing, second element <NUM> will not rotate around axis A as a result of an increase or decrease in the rotational speed of hub <NUM>.

Second element <NUM> is connected to first element <NUM> by a mechanism which causes first element <NUM> to rotate relative to hub <NUM> around axis A when second element <NUM> is moved parallel to said axis. For example, second element <NUM> may comprise an outer thread which engages with an inner thread of first element <NUM> such that an axial movement of second element <NUM> is translated into a rotational movement of first element <NUM>. As first element <NUM> is connected with an end of first part <NUM> (with the other end of first part <NUM> being attached to hub <NUM>), a rotational movement of first element <NUM> may increase or decrease a tension to which first part <NUM> is subjected.

If the rotational movement of first element <NUM> (caused by actuator <NUM>) decreases the tension to which first part <NUM> is subjected, the force of friction between first part <NUM> and second part <NUM> decreases. If the rotational movement of first element <NUM> (caused by actuator <NUM>) increases the tension to which first part <NUM> is subjected, the force of friction between first part <NUM> and second part <NUM> increases. Accordingly, the transmission of the braking force from disc brake <NUM> to the hub <NUM> can be controlled by positioning second element <NUM> through actuator <NUM>.

As illustrated by <FIG>, the same modifications that may be made to the anti-lock braking system <NUM> of <FIG> (as illustrated by <FIG>) may also be applied to the anti-lock braking system <NUM> of <FIG>.

As a further modification, actuator <NUM>, controller <NUM>, and inertial measurement unit <NUM> may not be static relative to axle <NUM> (as shown in <FIG>, <FIG>) but static relative to hub <NUM>. Likewise, first portion 38a of generator <NUM> may be static relative to hub <NUM> and second portion 38b of generator <NUM> may be static relative to axle <NUM> which may facilitate the provision of electric energy to those electric devices that are static to hub <NUM>. <FIG> illustrates an anti-lock braking system <NUM>, which does not correspond to the present invention, and which differs from the anti-lock braking systems <NUM> shown in <FIG> in that neither the first part <NUM> nor the second part <NUM> extend helically around the axle <NUM>. However, the anti-lock braking system <NUM> shown in <FIG> is similar to the anti-lock braking systems <NUM> shown in <FIG>, <FIG>, and <FIG> in that the anti-lock braking system <NUM> shown in <FIG> comprises controller <NUM> and inertial measurement unit <NUM> which are mounted on axle <NUM>.

In addition, although the detailed description has featured anti-lock braking systems <NUM> where a disc <NUM> of a disc brake <NUM> could be temporarily disconnected from the hub <NUM>, it is also contemplated to apply a braking force onto the hub <NUM> by closing the clutch instead of transmitting the breaking force through the closed clutch.

Claim 1:
An anti-lock braking system (<NUM>) for a vehicle, comprising:
a hub (<NUM>) having a hollow cavity (<NUM>) which is configured to accommodate an axle (<NUM>);
a device (<NUM>) having a first part (<NUM>) which is substantially static relative to the hub (<NUM>) and a second part (<NUM>) which may rotate relative to the hub (<NUM>) when the first part (<NUM>) and the second part (<NUM>) are disengaged; and
an actuator (<NUM>) which is configured to control a transmission of a braking force from a frame of the vehicle to the hub (<NUM>) by actuating the device (<NUM>);
characterized in that
one of the first part (<NUM>) and the second part (<NUM>) is configured to extend helically around the axle (<NUM>).