NL2028141B1

NL2028141B1 - Brake Torque Measuring System

Info

Publication number: NL2028141B1
Application number: NL2028141A
Authority: NL
Inventors: Van De Vorst Jaap; Kornelius Dijken Durandus; Adrianus Petrus Van Iersel Dennis
Original assignee: Atlas Technologies Holding Bv
Priority date: 2021-05-04
Filing date: 2021-05-04
Publication date: 2022-11-23
Also published as: WO2022233814A1

Abstract

The invention pertains to a measuring system for measuring brake torque generated by a brake system of a vehicle along an axis, comprising a brake caliper. The measuring system comprises a support structure, a measuring unit for measuring a quantity representative of the brake torque, and a stroke limiter. The support structure is adapted to rotatably connect the brake caliper to a frame, to allow the brake caliper to rotate relative to the frame along the axis along a stroke. The stroke limiter is arranged at an end of the stroke, to transfer at least part of the brake torque from the brake caliper to the frame when the brake caliper is at the end of the stroke. The invention further pertains to a vehicle comprising such a measuring system, and a brake test system comprising such a measuring system.

Description

P34949NLOO/SMI/MRA Brake Torque Measuring System This invention relates to a brake torque measuring system for a brake system of a vehicle, a vehicle comprising such a brake torque measuring system, and a brake test system comprising such a brake torque measuring system.

Vehicles, in general, comprise a plurality of wheels that are rotated in a forwards or backwards direction, relative to the orientation of the vehicle, to propel the vehicle. To slow down and/or stop a vehicle, the vehicle is provided with a brake system, configured to generate a brake force that slows down and/or stops the rotation of the wheels. The brake system is engaged if a brake action is performed. A brake action can be performed by, for example, the driver of the vehicle, or an automated system. Typically, such a brake system comprises a brake caliper and a brake disc. The brake disc is fixed to a wheel and rotates along with the wheel. The brake caliper is fixed to the body of the vehicle. The brake caliper interacts with the brake disc to generate a frictional force. The frictional force generates a brake torque along an axis that slows down and/or stops the rotation of the brake disc. Thereby, the rotation of the wheel that the brake disc is connected to is slowed down and/or stopped as well.

It is useful to measure the brake torque that is created by the interaction between the brake caliper and the brake disc. For example, in developing a new vehicle and/or brake system, engineers need to calibrate the system to generate an appropriate brake torque. In another example, maintenance personnel and/or mechanics perform diagnostics to identify the cause of a malfunction. In yet another example, the brake torque measurement is used to identify residual brake torque. Residual brake torque is brake torque that is generated by the brake system if no brake action is performed. For example, after a brake action has ended, the brake caliper is not fully retracted from the brake disc. This causes at least part of the brake torque that was generated during the brake action to remain, due to the interaction between the brake caliper and the brake disc. For another example, dirt and/or debris is accumulated within the brake system, for example on the brake disc, on the brake caliper and/or between the brake caliper and the brake disc. The interaction between the brake disc, the dirt and/or debris, and the brake caliper generates residual brake torque. For yet another example, due to wear and tear, unevenness in the surface of the brake disc and/or the brake caliper causes an interaction between the brake disc and brake caliper, even if no brake action is applied, causing residual brake torque. Residual brake torque is a source of drag, which reduces the energy efficiency of the vehicle. Detecting and/or reducing sources of drag is desirable in order to build vehicles having increased energy efficiency, as they provide cost- and environment-friendly transportation means.

From document JP2012202983A, a system is known for measuring the brake torque of a brake system in a brake dynamometer. The system comprises a support base and two swing shafts. A first swing shaft torque detector constituted by a first swing shaft load cell and a load cell pressure part is arranged to measure a drag torque by measuring a torque on the first swing shaft. A second swing shaft load cell is for measuring the braking torque generated in a caliper of a disc brake by measuring a torque on the second swing shaft. The second swing shaft load cell can be separated from the support base to be in a non-fixed state. In the non-fixed state, the torque cannot be detected by the second swing shaft load cell. In the fixed state, the torque can be detected by the second swing shaft load cell. The brake torque measuring system of JP2012202983A is provided as part of a brake dynamometer, i.e., as part of a test bench. A control device is provided for an operator to execute a drag torque measurement process for the disc brake or to execute a process for measuring the braking torque of the disc brake.

A disadvantage of the system described in JP2012202983A is that due to its size, it cannot be integrated in a vehicle, which would be desirable for example to perform diagnosis of a malfunction in the brake system of the vehicle. Further, the known system has to be adjusted when changing from the fixed state to the non-fixed state and vice versa.

In document US2018106319A1, various residual braking torque indication devices are described. The devices can include a sensorized brake pad. An output signal of the sensorized brake pad is processed to provide an indication of a residual braking torque. The residual braking torque indicator is calibrated to reference data to provide an actual measurement of the residual braking torque. As such, in the systems and method described in document US2018106319A1, residual braking torque is determined indirectly. It relies on certain characteristics that are exhibited in the output signal of the sensors that are used to measure brake torque. As such, it relies on complex mathematical analysis, and needs to be calibrated appropriately.

A disadvantage of US2018106319A1 is that it introduces an additional cost of set-up and operation, and it reduces the robustness of the system when it faces unexpected conditions for which it was not calibrated. Further, the output signal that is analyzed may be disturbed by other sources, such as vibrations or environmental conditions that do not indicate brake drag. As such, the robustness of the system is limited.

It is an objective of the invention to provide a system for measuring the brake torque and/or the residual brake torque generated by a brake system of a vehicle. It is further an objective of the invention to provide an improved brake torque measuring system and/or to provide an alternative for the prior art. It is further an objective of the invention to provide a vehicle comprising such a brake torque measuring system, and a brake test system comprising such a brake torque measuring system.

According to an aspect of the invention, one or more of the above objectives are achieved by a brake torque measuring system for a brake system of a vehicle, the brake system comprising a brake caliper arranged for interacting with a brake disc to create a brake torque along an axis; the brake torque measuring system comprising: a support structure for supporting the brake caliper; a measuring unit for measuring a quantity representative of the brake torque; a stroke limiter; wherein the support structure is adapted to rotatably connect the brake caliper to a frame, wherein the support structure is adapted to allow the brake caliper to rotate relative to the frame along the axis along a stroke; wherein the stroke limiter is arranged at an end of the stroke, wherein the stroke limiter is arranged to transfer at least part of the brake torque from the brake caliper to the frame when the brake caliper is at the end of the stroke.

According to the invention, the brake caliper transfers a brake torque to the support structure. Because the support structure allows to rotate the brake caliper relative to the frame along the axis, the brake torque causes the brake caliper to rotate relative to the frame. In case of a small brake torque, for example a residual brake torque, the rotation of the brake caliper is small. The brake caliper is able to make the small rotation within the stroke without reaching the stroke limiter at the end of the stroke. In case of a large brake torque, for example during a brake action, the caliper is rotated to the end of the stroke, at which the stroke limiter prevents the caliper to rotate any further. At the end of the stroke, the stroke limiter transfers at least part of the brake torque from the brake caliper to the frame.

The rotation of the brake caliper for small brake torques allows for accurate measurement of the small brake torques. When a large brake torque is applied to the brake caliper, the brake caliper rotates to the end of the stroke where the stroke limiter prevents further rotation of the brake caliper, allowing the large brake torque to be transferred to the frame. When the brake torque reduces to a small value again, the brake caliper rotates back away from the stroke limiter to allow further accurate measurements.

Because there is no need to make manual adjustments to deal with small brake torques or large brake torques, the brake torque measuring system according to the invention is suitable for use in a vehicle. When used in a test system, the invention improves the uptime of the test system. The brake system of the vehicle comprises a brake caliper, the brake caliper being arranged for interacting with a brake disc to create a brake torque along an axis. Due to the creation of the brake torque along the axis, the rotation of the brake disc is slowed down and/or stopped. As a result, the rotation of the wheel to which the brake disc is connected is slowed down and/or stopped as well. As a result, the vehicle is slowed down and/or stopped as well. The brake caliper engages the brake disc, creating a brake torque along the axis, as a result of a brake action. The brake action is started, for example, by the operator of the vehicle or an automated system. Typically, the brake torque generated during a brake action is a large brake torque, in the range of 500-5000 Nm. In other examples, brake torque generated during a brake action is in the range of 500-1000 Nm, in the range of 500-2000 Nm, in the range of 500-3000 Nm, in the range of 500-4000 Nm, or in the range of 500-6000 Nm.

When the brake action is finished, the brake caliper disengages the brake disc and the brake torque along the axis is ideally reduced to O Nm, such that the wheel rotates unhindered. However, due to e.g. contamination of the brake system, wear and tear of the brake system and/or the brake disc, or other related reasons, a residual brake torque along the axis may remain if no brake action is applied. Typically, residual brake torque is a small brake torque, in the range of 0-4 Nm. Other examples of ranges for residual brake torque are 0-10 Nm, 0-15 Nm, 0-20 Nm, and 0-500 Nm. The residual brake torque is for example caused by a drag force created by the interaction between the brake caliper and the brake disc. For example, after a brake action, the brake caliper does not fully release from the brake disc. This results in a frictional force between the brake caliper and the brake disc. For another example, debris is present between the brake caliper and the brake disc. This causes a frictional force due to the interaction between the debris, the brake caliper and the brake disc. For another example, due to wear and tear, the brake caliper and/or the brake disc have an uneven surface. The unevenness causes a frictional force due to the interaction of the brake caliper with the brake disc at the point where the unevenness occurs. For example, the interaction occurs periodically, for example once every rotation of the brake disc.

In a plurality of scenarios, it is of interest to measure the brake torque generated during a brake action and/or the residual brake torque generated if no brake action is applied. For example, when developing a new brake system for a vehicle, engineers calibrate the brake system to generate an appropriate brake torque during a brake action. This can e.g. be achieved by measuring the generated brake torque in a test system and/or in a vehicle, for example during a test drive, and comparing it to a desired result or range of results. For another example, during operation of the vehicle, the performance of the brake system is monitored to ensure an appropriate brake torque is generated during a brake action. This can e.g. be achieved by measuring the generated brake torque and comparing it to a desired result or range of results. For yet another example, during operation of the vehicle, it is desirable to detect residual brake torque. Residual brake torque is a source of drag, which 5 reduces the energy efficiency of the vehicle. By detecting the residual brake torque, the operator of the vehicle can be warned to e.g. have the vehicle serviced. The brake torque measuring system comprises a support structure for supporting the brake caliper. The support structure is adapted to rotatably connect the brake caliper to a frame and thereby allows the brake caliper to rotate relative to the frame along the axis along a stroke. As such, when the brake system creates a brake torque along the axis, e.g. if a brake action is applied or if residual brake torque is present, the brake caliper is rotated along the axis. The support structure introduces a degree of freedom for the brake caliper along the axis. The frame is an element that does not have the degree of freedom along the axis; i.e., the frame is stationary, whereas the wheel, the brake disc, and the brake caliper are rotatable relative to the frame along the axis. For example, the frame is connected to the body of a vehicle, or is connected to a support platform of a test system. The support structure comprises, for example, a rotational bearing or a hinge to rotatably connect the brake caliper to the frame. For example, the support structure comprises two parts that are rotatably to each other. One part is connected to the frame, whereas the other part is connectable to the brake caliper. The support structure is, for example, a single body. In another example, the support structure comprises multiple bodies that separated from each other. The multiple bodies cooperate together to rotatably connect the brake caliper to the frame.

The support structure comprises, for example, a spring-element adapted to rotate the brake caliper to a neutral position when no brake torque is applied to the brake caliper. The spring-element provides a force at an offset of the axis when the brake caliper is away from the neutral position. For example, the spring-element is extended or compressed in case the brake caliper is away from the neutral position. When the brake caliper is in the neutral position, the spring-element is not extended and not compressed. The spring-element is for example arranged between the frame and the support structure, or between the support structure and the measuring unit. The neutral position is, for example, in the center position of the stroke. The neutral position is, for example, at an end of the stroke opposite to the stroke limiter. This may allow an improved measurement of the brake torque in the forward drive direction of the vehicle in case ho measurement is needed in the backward drive direction or vice versa. The spring-element is, for example, integrated in the measuring unit. Instead of or in addition to the spring element, the support structure is orientated to use gravity to rotate the brake caliper to a neutral position when no brake torque is applied. The location of the center of gravity of the brake caliper and the support structure cause that gravity moves the brake caliper to a neutral position when no brake torque is applied. The brake torque measuring system further comprises a measuring unit for measuring a quantity representative of the brake torque. Brake torque can be measured in different ways and in different ranges. For example, brake torque generated during a brake action is in the range of 500-5000 Nm. In other examples, brake torque generated during a brake action is in the range of 500-1000 Nm, in the range of 500-2000 Nm, in the range of 500-3000 Nm, in the range of 500-4000 Nm, or in the range of 500-6000 Nm. Typically, residual brake torque is in the range of 0-4 Nm. Other examples of ranges for residual brake torque are 0-10 Nm, 0-15 Nm, 0-20 Nm, and 0-500 Nm. Providing a support structure that is adapted to rotatably connect the brake caliper to the frame, allows to select a measuring unit that is optimized to measure the brake torque in a desired range. For example, when the brake caliper is rotated along the axis along the stroke, the measuring unit measures a small brake torque, e.g., a residual brake torque, and is able to use other means for measuring the quantity representative of the brake torque than beyond the stroke. For example, the measuring unit uses means and/or adapts its method for measuring the brake torque in the range in which the brake caliper rotates. For example, by using components that are able to measure the quantity representative of the brake torque precisely along the stroke, a high level of precision in the measurements is reached. Such a measuring unit with a high level of precision is typically not able to withstand large brake torques. However, because the stroke limiter transfers at least part of the brake torque from the brake caliper to the frame when the brake caliper is at the end of the stroke, the stroke limiter protects the measuring unit from being overloaded. For example, the measuring unit uses means and/or adapts its method for measuring the brake torque beyond the range in which the brake caliper rotates. For example, by using robust components that are able to measure the quantity representative of the brake torque in a wide range, the robustness of the measuring unit is increased outside the range in which the brake caliper rotates. For example, the measuring unit is able to detect when the caliper is at the end of the stroke, and thus is able to indicate when the brake torque exceeds a certain value.

The quantity representative of the brake torque, measured by the measuring device, is for example a distance or a pressure. The measurement is performed, for example, by a sensor. Possible sensors include position sensors, angle sensors, displacement sensors, and pressure sensors. For example, the measurements are performed by an optical sensor such as a proximity sensor. For example, the measurements are performed by an acoustic sensor such as an ultrasonic sensor. For example, the measurements are performed by a piezometer, and/or a strain gauge. In another example, the measurement is performed by a gauge, indicating the quantity representative of the brake torque.

The brake torque measuring system further comprises the stroke limiter. The stroke limiter is arranged at the end of the stroke. The stroke limiter is arranged to transfer at least part of the brake torque from the brake caliper to the frame when the brake caliper is at the end of the stroke. As such, the rotation of the brake caliper along the axis is limited by the stroke limiter. The stroke limiter ensures that at least part of the brake torque is transferred to the frame, such that further rotation of the support structure is stopped, in order to slow down and/or stop the rotation of the brake disc. The stroke limiter is arranged such that the brake caliper is rotatable along the axis in a limited range, in which the brake torque is not transferred to the frame via the stroke limiter. This allows the selection of a measuring unit that is optimized to measure the brake torque in a desired range, for example within the range wherein the brake caliper is rotating along the stroke, and/or within the range wherein the brake torque is transferred at least partially to the frame. In an example, the stroke limiter is arranged to transfer at least part of the brake torque from the caliper to the frame at the two ends of the stroke. For example, one end of the stroke is associated with a direction of rotation of the brake disc and/or the brake caliper along the axis corresponding to a forwards driving direction. In the example, the other end of the stroke is associated with a direction of rotation of the brake disc and/or the brake caliper along the axis corresponding to a backwards driving direction.

In an embodiment according to the invention, the measuring unit is for measuring the quantity representative of the brake torque based on a rotational position of the brake caliper along the stroke.

The brake caliper is arranged to remain in the neutral position if there is no brake torque and/or residual brake torque generated by the interaction between the brake caliper and the brake disc. If there is a brake torque and/or residual torque generated by the interaction between the brake caliper and the brake disc, the brake caliper is arranged to rotate along the axis along the stroke. Typically, the rotation of the brake caliper is limited, i.e., the stroke over which the brake caliper is arranged to rotate is small, for example less than 10° or less than 5° or less than 2°. This ensures that if a brake action is applied, the relatively large brake torque associated with the brake action is transferred to the frame such that the brake disc is slowed down and/or stopped in an acceptable time frame. In these embodiments, the measuring unit is for measuring the quantity representative of relatively small brake torques in the range of rotation of the brake caliper. These quantities are measured based on the rotational pasition of the brake caliper along the stroke, i.e., the rotational position of the brake caliper relative to the neutral position of the brake caliper. For example, the quantity indicates a rotational position representing the amount of degrees the caliper has rotated relative to the neutral position.

The measuring unit is for example configured to perform measurements continuously. In another example, the measuring unit is configured to perform measurements at a fixed or variable time interval. In yet another example, the measuring unit is configured to calculate a moving average of measurements that are performed at a fixed or variable time interval.

The brake caliper, and the brake disc, have two rotation directions along the axis: clockwise and counter-clockwise. This corresponds, for example, to the vehicle that comprises the brake system travelling in a forwards or backwards direction. The measurement value indicates the quantity with which the brake caliper is rotated along the stroke, as well as optionally its direction. For example, optionally, a negative measurement corresponds to a counter-clockwise rotation, while a positive measurement corresponds to a clockwise rotation. In another example, the measurement value only indicates the quantity with which the brake caliper is rotated along the stroke. In other words, the measurement quantity in this example is the absolute value of a measurement value that also indicates the direction of the brake caliper. The quantity representative of the brake torque based on the rotational position is, for example, a time derivative of the rotational position of the brake caliper, such as the rotational speed of the brake caliper or the rotational acceleration of the brake caliper. In an example, the measuring unit indicates when the brake caliper reaches the rotational position in which the brake caliper is at the end of the stroke. In this example, the measuring unit is, for example, a contact switch such as a micro-switch.

In an embodiment according to the invention, the measuring unit is for measuring the quantity representative of the brake torque within a measurement range. For example, the measurement range is 0-4 Nm. The stroke limiter is arranged to transfer at least part of the brake torque from the brake caliper to the frame only when the brake torque exceeds the measurement range.

Residual brake torque is brake torque generated if no brake action is applied, and typically situates itself with a range of 0-4 Nm. Other examples of ranges of residual brake torque are 0-10 Nm, 0-15 Nm, 0-20 Nm, and 0-500 Nm. In some scenarios, to detect residual brake torque, these low torque quantities need to be measured with a high level of precision.

This is in contrast to higher torque quantities, such as when a brake action is applied, where in most scenarios a low precision is acceptable. Typically, the brake torque during a brake action is in the range of 500-5000 Nm and is thus significantly higher than the range of residual brake torque. In other examples, brake torque generated during a brake action is in the range of 500-1000 Nm, in the range of 500-2000 Nm, in the range of 500-3000 Nm, in the range of 500-4000 Nm, or in the range of 500-6000 Nm. The precision of the measurement in the range of residual brake torque has to be high, to ensure that residual brake torque is accurately detected.

In these embodiments, the stroke limiter is arranged such that the end of the stroke is at a point at which the end of the range of residual brake torque is reached.

For example, if only a small brake torque in the range of 0-4 Nm is applied by the brake caliper on the brake disc, the brake disc will rotate over a limited stroke relative to the frame.

For example, the brake caliper, supported by the support structure, is rotated within a range of -2° to 2°, relative to a neutral position in which no brake torque is present.

Other examples of rotation ranges are -1°to 1°, -0.5° to 0.59, -3° to 3° and -5° to 5°. The rotation range depends, for example, on the range of residual brake torque to be measured by the measuring unit.

Within that range, the brake torque generated by the interaction between the brake caliper and the brake disc is converted into rotational movement of the brake caliper.

In these examples, the measuring unit is configured to precisely measure the quantity representative of the brake torque within the measurement range of residual brake torque.

Beyond the measurement range, the caliper is at the end of the stroke, and the stroke limiter is arranged to transfer at least part of the brake torque from the brake caliper to the frame.

This ensures that a brake action slows down and/or stops the rotation of the brake disc.

In an embodiment, the support structure comprises a bearing.

The bearing is arranged to connect the brake caliper to the frame rotatably along the axis.

For example, the bearing is a rolling element bearing, a sliding bearing, or a fluid bearing, for example an air bearing.

The bearing allows the brake caliper to rotate along the axis, along the stroke, relative to the frame.

Bearings typically provide a good trade-off for cost, size, weight, carrying capacity, durability, accuracy and friction.

A fluid bearing, for example an air bearing, may have reduced hysteresis and friction compared to sliding or rolling element bearings.

Depending on, for example, the desired accuracy with which the brake torque is to be measured by the measuring unit, and on the available space, a suitable bearing can be selected.

This ensures that the quantity representative of the brake torque within the measurement range of residual brake torque can be precisely measured by the measuring unit.

In an embodiment, the support structure comprises a flexible hinge.

The flexible hinge is arranged to connect the brake caliper to the frame rotatably along the axis.

For example, the flexible hinge is a parallel flexure guiding, for example a leaf spring.

The flexible hinge allows the brake caliper to rotate along the axis, along the stroke, relative to the frame.

The flexible hinge may have reduced hysteresis and friction compared to, for example, sliding bearings or rolling element bearings.

As such, the friction caused by the flexible hinge while rotating the brake caliper relative to the frame can better be predicted and/or is less than in case a sliding bearing or a rolling element bearing would be used.

Because the friction is better predictable and/or there is less friction, the quantity representative of the brake torque within the measurement range of residual brake torque can be precisely measured by the measuring unit. In an embodiment according to the invention, the stroke limiter is arranged on the frame to contact the brake caliper at the end of the stroke.

By arranging the stroke limiter on the frame, the brake caliper comes into contact with the stroke limiter, and indirectly with the frame, at the end of the stroke. The contact between the brake caliper and the stroke limiter stops the rotation of the brake caliper, transferring at least part of the brake torque to the frame. The stroke limiter is for example a protrusion of the frame, or an element such as a bar that is fixed to the frame. The stroke limiter is manufactured from a material, such as metal, that is able to withstand the at least part of the brake torque. In other words, the stroke limiter is arranged such that it withstands the force that the brake caliper exerts on the stroke limiter when it comes into contact with the stroke limiter. The at least part of the brake torque is indirectly transferred to the frame, which causes the brake disc to be slowed down and/or stopped. For example, the brake caliper has a contact area arranged to contact the stroke limiter. For example, the contact area has a shape and/or is made from a durable material to allow the brake caliper to repeatedly contact the stroke limiter without substantial wear.

In an embodiment according to the invention, the stroke limiter is arranged on one of the support structure and the frame to transfer the at least part of the brake torque from the brake caliper via the support structure to the frame.

In these embodiments, the stroke limiter is arranged on the support structure, or on the frame, or on both the support structure and the frame. In the case that the stroke limiter is arranged on the support structure, the stroke limiter is arranged such that it contacts the frame at the end of the stroke. The contact between the stroke limiter and the frame transfers at least part of the brake torque from the brake caliper via the support structure to the frame. The stroke limiter is manufactured from a material, such as metal, that is able to withstand the at least part of the brake torque. In other words, the stroke limiter is arranged such that it withstands the force that the brake caliper exerts on the stroke limiter when it comes into contact with the stroke limiter. The at least part of the brake torque is directly or indirectly transferred to the frame, which causes the brake disc to be slowed down and/or stopped. By providing the stroke limiter to transfer the at least part of the brake torque via the support structure to the frame, no special adaptions of the brake caliper are needed. The brake caliper is mounted to the support frame using the same interface with which the brake caliper is designed to be mounted on a vehicle.

In an embodiment according to the invention, the stroke limiter is arranged on one of the measuring unit and the frame to transfer the at least part of the brake torque from the brake caliper via the measuring unit to the frame.

In these embodiments, the stroke limiter is arranged on the measuring unit, or on the frame, or on both the measuring unit and the frame. In the case that the stroke limiter is arranged on the measuring unit, the stroke limiter is arranged such that the stroke limiter contacts the frame at the end of the stroke. The contact between the stroke limiter and the frame transfers at least part of the brake torque from the brake caliper via the support structure to the frame. The stroke limiter is manufactured from a material, such as metal, that is able to withstand the at least part of the brake torque. In other words, the stroke limiter is arranged such that it withstands the force that the brake caliper exerts on the stroke limiter when it comes into contact with the stroke limiter. In these embodiments in particular, the the measuring unit is protected by the stroke limiter from the forces associated with the at least part of the brake torque that is transferred from the brake caliper via the measuring unit to the frame. The at least part of the brake torque is indirectly transferred to the frame, which causes the brake disc to be slowed down and/or stopped. The measuring device comprises, for example, a sensor in or on the measuring unit. The sensor may be unable to withstand a large pressure force. So by arranging the stroke limiter on the measuring unit, the stroke limiter is arranged to prevent a large pressure force to be applied to the sensor. For example, the sensor is able to deform a small amount due to a small pressure force. When the pressure force, for example from the frame, becomes too large, the sensor is pushed inside the stroke limiter. Any additional pressure force is then applied to the stroke limiter.

In an embodiment, the measuring unit comprises a gauge for indicating the quantity representative of the brake torque.

The quantity representative of the brake torque is communicated to, for example, a test engineer who is testing the performance of the brake system, or to the driver of the vehicle. A gauge is used for this purpose in these embodiments. For example, the gauge is mechanically connected to the brake caliper and/or the support structure and/or the measuring unit. The gauge is for example arranged to remain in a neutral position if the brake caliper is in a neutral position in which no brake torque is present. The gauge is for example arranged to rotate along the axis by following the rotation of the brake caliper along the stroke. The gauge is for example a needle, or a bar, the end of the gauge indicating the quantity representative of the brake torque. In an example, the needle or bar is fixed to the support structure. A scale is provided on the frame. Depending on the rotational position of the support structure, the needle or bar indicates a value on the scale on the frame.

In an embodiment, the measuring unit comprises a sensor for providing a signal representative of the brake torque.

The sensor is provided in the measuring unit to measure a quantity representative of the brake torque. The sensor provides a signal representative of the brake torque, which signal can be used by other systems. Possible sensors include position sensors, angle sensors, displacement sensors, and pressure sensors. For example, the measurements are performed by an optical sensor such as a proximity sensor. For example, the measurements are performed by an acoustic sensor such as an ultrasonic sensor. For example, the measurements are performed by a piezometer, and/or a strain gauge.

For example, the signal is used in a monitoring system for monitoring the residual brake torque. The monitoring system is, for example, adapted to notify the driver of the vehicle of the drag caused by the residual brake torque. In this example, the driver receives information related to the drag associated with the residual brake torque, and can decide to have the vehicle serviced. In another example, the signal is compared to a threshold value. If the signal exceeds the threshold value, a warning is presented to the driver of the vehicle. The warning indicates a malfunction of the vehicle. The driver can decide to have the vehicle serviced based on the warning. In another example, the signal is logged to an internal memory of the vehicle. The logged signal can be retrieved by a mechanic for diagnostics purposes, for example, when servicing the vehicle. Alternatively or additionally, the logged signal is sent to the manufacturer of the vehicle, where the logged signal is used for data analysis purposes, for example on the individual brake system or on all the brake systems that it receives logged signals from. In yet another example, the signal is used during testing of a brake system by a test engineer. In this example, the signal is used to quantify and gain insight into the generated brake torque, in particular in the residual brake torque. The insights are for example used to calibrate and optimize the brake system, to, for example, reduce and/or eliminate residual brake torque.

In an embodiment, the sensor is a force transducer, for example a load cell or a strain gauge, arranged between the support structure and the frame or between the brake caliper and the frame to generate a force on the force transducer based on a rotational position of the brake caliper along the stroke.

A force transducer, such as a load cell and a strain gauge, is able to convert a force into a signal. A load cell is, for example, attached to the support structure or the brake caliper.

In this case, the load cell is deformed as the caliper rotates along the axis along the stroke. At the same time, the clearance between the caliper and the stroke limiter is reduced, until the end of the stroke is reached. When the brake caliper is at the end of the stroke, at least part of the brake torque from the brake caliper is transferred to the frame via the load cell. The load cell is able to withstand the brake torque. In this example, the load cell is the stroke limiter. In an example, further deformation of the load cell is stopped if the brake torque is transferred to the frame. In this example, the load cell is able to measure residual brake torque in the range specified by the limited rotation of the brake caliper along the axis along the stroke. In another example, the load cell is also deformed if the brake torque is transferred to the frame. In this example, the load cell is able to measure residual brake torque, as well as the brake torque generated during a brake action. In yet another example, two load cells are arranged. In this example, one load cell is arranged to measure the residual brake torque in the range specified by the limited rotation of the brake caliper along the axis along the stroke. In this example, the second load cell is arranged to measure the brake torque generated during a brake action.

In an embodiment, the sensor is a displacement sensor. The sensor is arranged to measure a quantity representative of the rotational position of the caliper along the stroke.

A displacement sensor is used to measure the distance between the sensor and a target element, for example the frame or the stroke limiter. The displacement sensor is for example arranged on the caliper. A displacement sensor is for example an optical displacement sensor, a linear proximity sensor, or an ultrasonic displacement sensor. In this arrangement, the displacement sensor provides a measurement of the position of the brake caliper along the axis along the stroke. Based on this position information, the residual brake torque can be deduced. If the brake caliper reaches the end of the stroke, at least part of the brake torque is transferred to the frame. The displacement sensor is configured to at least detect that the brake caliper has reached the end of the stroke. Since the rotation of the brake caliper along the axis stops at the end of the stroke, the signal provided by the displacement sensor will remain unchanged. As such, the signal provided by the displacement sensor can be used to quantify the residual brake torque in the limited rotation range of the brake caliper along the axis along the stroke.

In an embodiment according to the invention, the brake torque measuring system comprises a signal processing unit, wherein the signal processing unit is configured to: receive the signal provided by the sensor; process the signal to obtain a signal processing result; generate a communication signal, representative of the signal processing result.

The signal processing unit is for example a computing device, comprising a memory and a processor. The processor is configured to execute a set of processing instructions. The set of processing instructions are configured to cause the computing device to process a signal received by the processing unit from the sensor to obtain a signal processing result. The signal is for example received by a communication link between the sensor and the signal processing unit. For example, the signal is an electrical signal transmitted by the sensor via a central communication system, such as a bus, to the signal processing unit. The signal is representative of a quantity representative of the brake torque.

The processing of the signal comprises, for example, comparing the received signal to a predefined threshold value. If the received signal exceeds the predefined threshold, the signal processing result for example is representative of a warning. The warning indicates that residual brake torque is high. If the brake torque measuring system is integrated in a vehicle, this indicates to the operator of the vehicle that the vehicle needs to be serviced. Alternatively or additionally, the warning is used by a technician servicing the brake system to diagnose the cause of a malfunction. In this example, the threshold is for example set to 0.1 Nm, 0.5 Nm, 1 Nm, or 3 Nm. In an example, the received signal is compared to a second predefined threshold value. For example, the second predefined threshold is set to 4 Nm, or 10 Nm, or 15 Nm, 20 Nm, or 500 Nm. If the received signal exceeds the predefined threshold, but does not exceed the second predefined threshold, the signal processing result for example is representative of a warning. The warning indicates that residual brake torque is high. If the brake torque measuring system is integrated in a vehicle, this indicates to the operator of the vehicle that the vehicle needs to be serviced. In another example, if the received signal exceeds the predefined threshold, the signal processing result is used to distinguish between residual brake torque and brake torque during a brake action. For example, the predefined threshold is set to 4 Nm, or 10 Nm, or 15 Nm, 20 Nm, or 500 Nm. In this example, if the signal exceeds the predefined threshold, the signal processing result indicates that a brake action is applied.

The processing of the signal comprises, in another example, aggregating a plurality of signal values. In this example, the signal processing result is representative of the aggregate of the plurality of signal values, for example, a moving average, or a median, or a minimum or maximum signal value. In another example, the processing of the signal also comprises comparing the aggregate of the plurality of signal values to a predefined threshold value. If the received signal exceeds the predefined threshold, the signal processing result for example is representative of a warning. The warning indicates that residual brake torque is high.

In yet another example, the processing of the signal comprises copying the signal. In this example, the signal processing result is representative of the unmodified signal.

The signal processing unit is further configured to generate a communication signal, representative of the signal processing result. For example, the communication signal is an electrical signal that is transmitted by the signal processing unit via a central communication system, such as a bus.

The communication signal can be received by other subsystems that the signal processing unit is connected to via the communication system.

For example, the communication signal, representative of the signal processing result, is used in a test procedure for a brake system by an engineer.

The communication signal is for example interpreted and displayed on a system used by the engineer for calibrating or diagnosing the performance of a brake system in real-time.

For another example, the communication signal, representative of the signal processing result, is logged to a memory unit in a vehicle or in a test system comprising the brake torque measuring system.

The log retains the history of signal processing results, for example, of measured sensor values, indicative of the brake torque during a brake action and/or the residual brake torque.

The log is for example used by an engineer who calibrates the system, or a mechanic servicing the system to diagnose the cause of a malfunction.

In another example, the communication signal, representative of the signal processing result, is used by a display system to display information to the operator of the vehicle comprising the brake torque measuring system.

For example, the operator receives through the display system information on the energy use of the vehicle, which comprises the energy losses through residual brake drag.

For another example, the operator receives through the display a system a warning indicative of a dangerous situation, for which the vehicle needs to be serviced.

As such, the display system in this example uses the information comprised in the communication signal to enhance the user experience, by providing additional information and warnings to the operator of the vehicle.

According to another aspect of the invention, one or more of the above objectives are achieved by: a vehicle comprising a body, a brake system and the brake torque measuring system according to the first aspect of the invention.

The brake system comprises a brake caliper and a brake disc.

The brake disc is arranged to interact with the brake caliper to create the brake torque along the axis.

The body comprises the frame.

A vehicle comprises a plurality of wheels, for example four, each rotatable against a surface, propelling the vehicle.

The vehicle is propelled in a forwards or a backwards direction relative to the orientation of the vehicle.

The one or more wheels of the vehicle is for example powered or passive.

The vehicle is for example an automobile, e.g. a commercially available automobile for use on public roads.

The vehicle is for example an at least partially electrically powered vehicle.

The vehicle is for example an electrically powered vehicle, further comprising one or more solar panels for providing power.

One or more of the wheels are provided with one or more brake discs, each brake disc being connected to a wheel, such that the brake disc follows the rotation of the wheel and vice versa.

In this aspect of the invention, the brake torque measuring system is integrated in a vehicle. The frame is comprised by the body of the vehicle. For example, the frame is a component of the body, or is attached to the body with a mechanic connection. The support structure of the brake torque measuring system connects the brake caliper of the brake system of the vehicle rotatably to the frame, i.e., directly or indirectly to the body of the vehicle. The body, relative to the brake caliper, provides a neutral reference position over which the brake caliper rotates along the axis along the stroke. Further, the body also interacts, directly or indirectly, with the brake caliper to transfer at least part of the brake torque to the body at the end of the stroke. For example, the body comprises the stroke limiter. The interaction between the stroke limiter and the brake caliper at the end of the stroke causes the at least part of the brake torque to be transferred to the body. In another example, the brake caliper and/or the measurement device comprise the stroke limiter. In this example, the interaction between the stroke limiter and the body at the end of the stroke causes the at least part of the brake torque to be transferred to the body. In other words, the interaction between the stroke limiter, the body of the vehicle, the measurement device, and/or the brake caliper, limit the rotation of the brake caliper. The brake caliper is rotatably connected to the body by, for example, a bearing or a flexible hinge.

As such, the additional components required to integrate the brake torque measuring system in a vehicle are limited in number. As such, the brake torque measuring system can be readily integrated in a vehicle.

In an embodiment according to the second aspect of the invention, the frame is an upright for rotatably holding the wheel, wherein the wheel is rotatable along the axis relative to the upright.

The body of the vehicle comprises several elements, one of which is the wheel assembly that holds the wheel and allows the wheel to rotate along the axis, in a direction associated with the driving direction of the vehicle. The upright is a component of the wheel assembly that is connected to the suspension of the vehicle and rotatably holds the wheel and the brake disc. Typically, the brake caliper of the brake system of the vehicle is connected to the upright as well. In these embodiments, the brake caliper of the brake system is rotatably connected to the upright via the support structure. The upright, relative to the brake caliper, provides a neutral reference position over which the brake caliper can rotate along the axis along the stroke. Further, the upright also interacts, directly or indirectly, with the brake caliper to transfer at least part of the brake torque to the upright at the end of the stroke. For example, the upright comprises the stroke limiter. In this example, the interaction between the stroke limiter and the brake caliper at the end of the stroke causes the at least part of the brake torque to be transferred to the upright. In another example, the brake caliper and/or the measurement device comprise the stroke limiter. In this example, the interaction between the stroke limiter and the upright at the end of the stroke causes the at least part of the brake torque to be transferred to the upright. In other words, the interaction between the stroke limiter, the upright of the wheel assembly of the body of the vehicle, the measurement device, and/or the brake caliper, limit the rotation of the brake caliper. The brake caliper is rotatably connected to the upright by, for example, a bearing or a flexible hinge.

In another embodiment according to the second aspect of the invention, the vehicle comprises a number of brake torque measuring systems equal to the number of wheels of the vehicle. The support structure of each brake torque measuring system is arranged to support the brake caliper of a corresponding wheel.

The vehicle comprises at least one wheel, for example two wheels, for example three wheels, for example four wheels. The vehicle comprises a number of brake systems, that is for example equal to the number of wheels. In this example, all wheels can be slowed down and/or stopped by their respective brake systems. In some examples, the brake systems are actuated individually, i.e., the brake torque created by the brake caliper of the individual brake systems and their respective brake discs can be regulated individually. In another example, the brake systems are actuated together, i.e., the brake torque created by the brake caliper of all brake systems and their respective brake discs is the same.

In this embodiment, the brake torque generated by the brake systems associated to the wheels of the vehicle can be measured individually by providing a number of brake torque measuring systems for each of the wheels of the vehicle. The support structure of each brake torque measuring system is arranged to rotatably connect the brake caliper of a corresponding wheel to the corresponding frame. For example, the frame is an upright of the wheel assembly that holds the corresponding wheel.

In this embodiment, the measuring unit of the individual brake torque measuring systems measure a quantity representative of the brake torque that is created by the interaction between the brake caliper and the brake disc of their respective wheel. As such, the quantities measured by the measuring unit of the individual brake torque measuring systems can be different for each wheel.

The signal processing unit is for example configured to receive all signals provided by the sensor of the measuring unit of the individual brake torque measuring systems. Subsequently, signal processing unit can obtain multiple signal processing results, corresponding to the signals received, and generate multiple communication signals, representative of the individual signal processing results. Alternatively, multiple signal processing units are provided, each signal processing unit being configured to receive a signal provided by the sensor of the measuring unit of a single brake torque measuring system. Subsequently, the individual signal processing units obtain a signal processing result corresponding to the received signal, and generate a communication signal, representative of the signal processing result.

According to another aspect of the invention, one or more of the above objectives are achieved by a brake test system, comprising: a support platform; the brake torque measuring system according to the first aspect of the invention; wherein the support platform comprises the frame and wherein the brake caliper is rotatably connected to the frame by the support structure.

A test system is for example used during the development phases of a vehicle to for example predict, optimize and calibrate the behavior of the vehicle. The test system mimics, and/or only includes a subset of, features of the vehicle that are being tested. For example, the test system only comprises and/or mimics the features of a steering mechanism, or a brake system of the vehicle. Using the test system, an engineer can test the behavior of the system in different scenarios.

The brake test system comprises components to predict the behavior of a brake system of a vehicle. It is used, for example, by engineers to validate the behavior of the brake system in the development stage, or to calibrate the brake system, or to diagnose the brake system to find the cause of a malfunction.

The brake test comprises the brake torque measuring system. When the support structure rotatably connects a brake caliper to the frame of the brake torque measuring system, the brake test system is stationary relative to the brake caliper. This is achieved by a support platform, to which the other components of the brake test system are attached, the support platform being configured to attach to the ground or to stand on the ground. As such, the support platform, relative to the brake caliper, provides a neutral reference position over which the brake caliper can rotate along the axis along the stroke. At the same time, the support platform also provides a neutral reference position over which a brake disc, with which the brake caliper interacts to create a brake torque along the axis, can rotate along the axis. As such, when the brake caliper and the brake disc interact to create a brake torque, the support structure remains stationary while the brake disc is slowed down and/or stopped. According to this aspect of the invention, the support platform comprises the frame, the support structure being adapted to connect the brake caliper rotatably to the frame.

Further, the support platform also interacts, directly or indirectly, with the brake caliper to transfer at least part of the brake torque to the support platform at the end of the stroke.

For example, the support platform comprises the stroke limiter. In an example, the interaction between the stroke limiter and the brake caliper at the end of the stroke causes the at least part of the brake torque to be transferred to the support platform. In other embodiments, the brake caliper and/or the measurement device comprise the stroke limiter. In these embodiments, the interaction between the stroke limiter and the support platform at the end of the stroke causes the at least part of the brake torque to be transferred to the support platform. In other words, the interaction between the stroke limiter, the support platform of the test system, the measurement device, and/or the brake caliper, limit the rotation of the brake caliper. The brake caliper is rotatably connected to the support platform by, for example, a bearing or a flexible hinge. As such, the brake torque measuring system can be readily integrated in a brake test system.

The invention is described below with reference to the figures. These figures serve as examples to illustrate the invention, and will not be construed as limiting the scope of the claims. In the different figures, like features are indicated by the like reference numerals. In the figures: Fig. 1 schematically shows a brake torque measuring system according to a first embodiment of the invention. Fig. 2 schematically shows a side view of a brake torque measuring system according to the first embodiment of the invention. Fig. 3a schematically shows a detailed view of a brake torque measuring system according to the first embodiment of the invention. Fig. 3b schematically shows a detailed view of a side view of a brake torque measuring system according to the first embodiment of the invention. Fig. 4 schematically shows a detailed view of a brake torque measuring system according to the first embodiment of the invention. Fig. 5 is a block diagram of a measuring system of the brake torque measuring system according to the first embodiment of the invention. Fig. 6 schematically shows a detailed view of a brake torque measuring system according to a second embodiment of the invention. Fig. 7 schematically shows a detailed view of a brake torque measuring system according to a third embodiment of the invention. Fig. 8 schematically shows a detailed view of a brake torque measuring system according to a fourth embodiment of the invention. Fig. 9 schematically shows a detailed view of a side view of a brake torque measuring system according to a fifth embodiment of the invention. Fig. 10a schematically shows a brake torque measuring system according to a sixth embodiment of the invention.

Fig. 10b schematically shows a detailed view of a brake torque measuring system according to the sixth embodiment of the invention.

Fig. 11a schematically shows a brake torque measuring system according to a seventh embodiment of the invention.

Fig. 11b schematically shows a detailed view of a brake torque measuring system according to the seventh embodiment of the invention.

Fig. 12a schematically shows a brake torque measuring system according to an eighth embodiment of the invention.

Fig. 12b schematically shows a detailed view of a brake torque measuring system according to the eighth embodiment of the invention.

Fig. 13 schematically shows a side view of a brake torque measuring system according to a ninth embodiment of the invention.

Fig. 14 schematically shows a portion of a vehicle according to an embodiment of a further aspect of the invention.

Fig. 15 schematically shows a portion of a test system according to an embodiment of a further aspect of the invention.

Figs. 1-4 schematically show a brake torque measuring system 110 according to a first embodiment of the invention.

Fig. 1 shows a front view of the brake torque measuring system 110, Fig. 2 shows a side view of the brake torque measuring system 110, and Figs. 3 - 4 show a detailed view of the brake torque measuring 110. Fig. 2 further schematically shows a brake system 201 of a vehicle, which brake system 201 comprises a brake caliper 101 and a brake disc 102. The brake caliper 101 and brake disc 102 are arranged to create a brake torque along an axis 103. The brake torque measuring system 110 comprises a support structure 104. The support structure 104 rotatably connects the brake caliper 101 to the frame 106. In the shown embodiment, the frame 106 is an upright of the vehicle.

The upright is a component of a wheel assembly of the vehicle that is connected to the suspension of the vehicle and rotatably holds the brake disc.

For operational use of the vehicle, the upright rotatably supports a wheel of the vehicle.

The wheel is rotatable along the axis 103 relative to the frame 108. The support structure 104 allows the brake caliper 101, which it connects to the frame 106, to rotate along the axis 103 along a stroke 107. As such, the support structure 104 introduces a degree of freedom for the brake caliper 101 along the axis 103. A stroke limiter 105 is arranged on the support structure 104. In the shown embodiment, the stroke limiter 105 interacts with a protruding element 109 of the frame 106. The stroke limiter 105 is a slot in the support structure 104. The protruding element 109 is fixedly attached to the frame 108. As such, the protruding element 109 stays stationary whereas the brake caliper 101 and/or the support structure 104 are rotatable relative to the protruding element 109 along the axis 103. The stroke limiter 105 has two opposite sides which define ends 301 of the stroke 107. As the support structure 104 rotates along the axis 103, the distance between the protruding element 109 and one of the opposite sides of the stroke limiter 105 diminishes. When the side of the stroke limiter 105 touches the protruding element 109, one end 301 of the stroke 107 is reached. When the end 301 of the stroke 107 is reached, at least part of the brake torque from the brake caliper 101 is transferred to the frame 106. As such, the rotation of the brake caliper 101 along the axis 103 is limited by the interaction between the stroke limiter 105 and the protruding element 109. The stroke limiter 105 ensures that at least part of the brake torque generated by the interaction between the brake caliper 101 and the brake disc 102 is transferred to the frame 1086, such that further rotation of the brake caliper 101 and/or the support structure 104 is stopped. By stopping further rotation of the brake caliper 101 and/or the support structure 104, the brake torque between the brake caliper 101 and the brake disc 102 can be further increased quickly, because the increased brake torque is directly transferred to the frame 106 via the stroke limiter 105. This results in a quick and safe brake action, for example, if a fast deceleration of the vehicle is desired.

In the embodiment shown in Figs. 1-4, the support structure 104 further comprises multiple flexible hinges 108, wherein the flexible hinges 108 connect the brake caliper 101 to the frame 106. The flexible hinges 108 are connected to one end to the frame 106 and with the other end to the support structure 104. The flexible hinges 108 are for example parallel flexure guidings, for example, leaf springs. The flexible hinges 108 are flexed when a force is generated as the result of an interaction between the brake caliper 101 and the brake disc

102. Through the flexing of the flexible hinges 108, the support structure 104 rotates along the axis 103.

In Fig. 4, it is shown that the brake torque measuring system 110 according to the embodiment shown in Figs. 1-4 comprises a measuring unit 401. The measuring unit 401 is for measuring a quantity representative of the brake torque generated by the interaction between the brake caliper 101 and the brake disc 102. Brake torque can be measured in different ways and in different ranges. For example, brake torque generated during a brake action is in the range of 500-5000 Nm. Typically, residual brake torque is in the range of 0-4 Nm. The measuring unit 401 is configured to at least measure residual brake torque generated by the interaction between the brake caliper 101 and the brake disc 102 when no brake action is performed. Such residual brake torque can occur, for example, if the brake caliper 101 is not fully retracted from the brake disc 102 after a brake action has ended. For another example, dirt and/or debris is accumulated within the brake system 201, for example on the brake disc 102, on the brake caliper 101 and/or between the brake caliper 101 and the brake disc 102. The interaction between the brake disc 102, the dirt and/or debris, and the brake caliper 101 generates residual brake torque. For yet another example, due to wear and tear, unevenness in the surface of the brake disc 102 and/or the brake caliper 101 causes an interaction between the brake disc 102 and brake caliper 101, even if no brake action is applied, causing residual brake torque. The measuring unit 401 is optionally configured to measure the brake torque generated during a brake action.

Due to the stroke 107 along which the brake caliper 101 is rotatable along the axis 103, at least part of the residual brake torque is transformed into rotation of the brake caliper 101 along the axis 103. As such, due to the support structure 104 rotatably connecting the brake caliper 101 to the frame 108, a measuring unit 401 that is optimized to measure the brake torque in a desired range is selected, for example. Alternatively, the measuring unit 401 adapts its method of measuring the brake torque based on whether the brake caliper 101 is rotating along the axis 103 or is stationary, i.e., the brake caliper 101 has reached the end of the stroke 107.

Fig. 5 is a block diagram of a measuring system of the brake torque measuring system 110 according to the first embodiment of the invention. In the shown embodiment, the brake torque measuring system 110 comprises a signal processing unit 501. The signal processing unit 501 is connected to the measuring unit 401. The signal processing unit 401 is configured to receive a signal representative of the brake torque from the measuring unit 501. For example, the signal processing unit 501 is a computing device, comprising a memory and a processor. The processor is configured to execute a set of processing instructions. The set of processing instructions are configured to cause the computing device to process a signal received by the processing unit from the sensor to obtain a signal processing result. The signal processing result is representative of, for example, a warning or an error.

The signal processing unit 501 is further configured to generate a communication signal representative of the signal processing result. For example, the communication signal is an electrical signal that is transmitted by the signal processing unit via a central communication system, such as a bus (not shown). The communication signal can be received by other subsystems that the signal processing 501 unit is connected to via the communication system.

Fig. 8 schematically shows a detailed view of a brake torque measuring system 110 according to a second embodiment of the invention. The second embodiment is identical to the first embodiment, with the exception of the measuring unit 401. The measuring unit 401 in the second embodiment is an alternative for or additional to the measuring unit 401 of the first embodiment. The measuring unit 401 in the second embodiment comprises a gauge 601 for indicating the quantity representative of the brake torque. The gauge 601 is placed on the support structure 104. As such, if the support structure 104 rotates along the axis 103 along the stroke 107, the gauge 601 rotates along the axis 103 with an equal amount as the support structure 104. In the shown embodiment, a scale 602 is provided on the frame 106. As the gauge 601 rotates along the axis 103, a value on the scale 602 is indicated. The scale 602 has at least a range for indicating values within the range of rotation of the brake caliper 101 along the stroke 107. The values on the scale 602 may be calibrated, for example such that a value on the scale 602 corresponds to a residual brake torque value.

The scale 602 is based on a combined center of mass 1101 of the brake caliper 101 and the support structure 104, and on a distance from the axis 103 to the combined center of mass 1101 in a direction perpendicular to the axis 103. The combined center of mass 1101 is indicated in Fig. 11a. In Fig. 11a, the axis 103 is indicated by a point, as the axis 103 is perpendicular to the shown perspective, i.e., the axis 103 is parallel to the z-axis. In case no brake torque is applied to the brake caliper 101, gravity rotates the support structure 104 such that the combined center of mass 1101 is directly below the axis 103. The gravitational force acting on the combined center of mass 1101 is directed through the axis 103 in this rotational position of the support structure 104. The support structure 104 is in a neutral position. In case a brake torque is applied to the brake caliper 101, the brake caliper 101 and the support structure 104 are rotated away from the neutral position. Gravity causes a torque on the support structure 104, because the gravitational force acting on the combined center of mass 1101 is no longer directed through the axis 103, but at an offset to the axis 103 instead. The larger the brake torque, the further the support structure 104 is rotated away from the neutral position, and the larger the offset to the axis 103 is. In case the brake torque is applied no longer, the gravitational force brings the support structure 104 back to the neutral position.

Fig. 7 schematically shows a detailed view of a brake torque measuring system 110 according to a third embodiment of the invention. The third embodiment is identical to the first embodiment, with the exception of the measuring unit 401. The measuring unit 401 in the third embodiment is an alternative for or additional to the measuring unit 401 of the first embodiment. The measuring unit 401 in the third embodiment comprises a displacement sensor 701 for providing a signal representative of the brake torque. The displacement sensor 701 is arranged such that it detects the rotation of the support structure 104 as it rotates along the axis 103 along the stroke 107. The displacement sensor 701 is calibrated to detect, for example, a neutral position of the support structure 104 as shown in the figure. The support structure 104 is adapted to rotate in either direction, for example, in a clockwise or counter-clockwise direction as shown in the figure. The displacement sensor 701 is positioned such that the support structure 104 moves towards the displacement sensor 701 in case the support structure 104 rotates in clockwise direction, and the support structure 104 moves away from the displacement sensor 701 if it rotates in counter-clockwise direction. For example, the displacement sensor is configured to measure a value of zero if the support structure 104 is in the neutral position, and to measure a positive value if the support structure 104 is rotated in a clockwise direction, and to measure a negative value if the support structure 104 is rotated in a counter-clockwise direction.

Fig. 8 schematically shows a detailed view of a brake torque measuring system 110 according to a fourth embodiment of the invention. The fourth embodiment is identical to the first embodiment, with the exception of the measuring unit 401. The measuring unit 401 in the fourth embodiment is an alternative for or additional to the measuring unit 401 of the first embodiment. The measuring unit 401 in the fourth embodiment comprises a force transducer 801, for example a load cell, for providing a signal representative of the brake torque. The force transducer 801 is arranged such that it detects the rotation of the support structure 104 as the support structure 104 rotates along the axis 103 along the stroke 107. For example, the force transducer is mounted on the frame 106. The force transducer 801 is connected to the support structure 104 via rod 802. If the support structure 104 rotates, the force transducer 801 is deformed. The deformation causes the force transducer 801 to detect the rotation and to generate a signal, for example an electrical signal, representative of the detected rotation of the support structure 104. For example, the force transducer 801 is calibrated to have no deformation in the neutral position of the support structure 104, as shown in the figure. For example, the displacement sensor is configured to measure a value of zero if the support structure 104 is in the neutral position, and to measure a positive value if the support structure 104 is rotated in a counter-clockwise direction. To measure a rotation of the support structure 104 in the clockwise direction, an alternative position of the force transducer 801 or an alternative connection between the force transducer 801 and the support structure 104 is provided. Alternatively, a second force transducer is provided on the opposite side of the force transducer 801 for measuring the rotation of the support structure 104 in the clockwise direction.

Fig. 9 schematically shows a detailed view of a side view of a brake torque measuring system 110 according to a fifth embodiment of the invention. The fifth embodiment is identical to the fourth embodiment, with the exception of the measuring unit 401 (not shown). The measuring unit 401 (not shown) in the fifth embodiment is an alternative for or additional to the measuring unit 401 of the fourth embodiment. The measuring unit 401 (not shown) in the fifth embodiment comprises two force transducers 801. The force transducers 801 are provided on the flexible hinge 108. The force transducers 801 are arranged to detect the flexing of the flexible hinge 108. The flexible hinge 108 flexes as the support structure 104 rotates along the axis 103. For example, when the support structure 104 rotates along the axis 103, the flexible hinge 108 is deformed into an S-shape, which causes one of the force transducers 801 to elongate and which causes the other of the force transducers 801 to contract. For another example, when the support structure 104 rotates along the axis 103,

both of the force transducers 801 elongate. For another example, when the support structure 104 rotates along the axis 103, both of the force transducers 801 contract. As such, the embodiment provides an alternative configuration for detecting the rotation of the support structure 104 along the axis 103.

Fig. 10a schematically shows a brake torque measuring system 110 according to a sixth embodiment of the invention and Fig. 10b schematically shows a detailed view of a brake torque measuring system 110 according to the sixth embodiment of the invention. The sixth embodiment is identical to any one of the embodiments described above, with the exception of the stroke limiter 105. The stroke limiter 105 in the sixth embodiment is an alternative for or additional to the stroke limiter 105 of any of the embodiments described above. In the embodiment shown in Figs. 10a-10b, three flexible hinges 108 connect the support structure 104 to the frame 106. The stroke limiter 105 is arranged on the support structure 104. The stroke limiter 105 interacts with a recess 1101 of the frame 106. The stroke limiter 105 is an element of the support structure 104 that fits within the recess 1101.

As such, the stroke limiter 105 rotates along with the brake caliper 101 and/or the support structure 104 along the axis 103. As the support structure 104 rotates along the axis 103, the distance between the stroke limiter 105 and a side of the recess 1101 diminishes. When the stroke limiter 105 touches the side of the recess 1101, an end 301 of the stroke 107 is reached. When the end 301 of the stroke 107 is reached, at least part of the brake torque from the brake caliper 101 is transferred to the frame 108. As such, the rotation of the brake caliper 101 along the axis 103 is limited by the interaction between the stroke limiter 105 and the recess 1101. The stroke limiter 105 ensures that at least part of the brake torque generated by the interaction between the brake caliper 101 and the brake disc 102 is transferred to the frame 106 when the end 301 of the stroke 107 is reached, such that further rotation of the brake caliper 101 and/or the support structure 104 is stopped.

Fig. 11a schematically shows a brake torque measuring system 110 according to a seventh embodiment of the invention and Fig. 11b schematically shows a detailed view of a brake torque measuring system 110 according to the seventh embodiment of the invention. The seventh embodiment is identical to any one of the embodiments described above, with the exception of the stroke limiter 105. The stroke limiter 105 in the seventh embodiment is an alternative for or additional to the stroke limiter 105 of any of the embodiments described above. In the embodiment shown in Figs. 11a-11b, the stroke limiter 105 is arranged on the frame 106. In the shown embodiment, the stroke limiter 105 interacts with the brake caliper

101. The stroke limiter 105 is an element of the frame 106 that is arranged next to the brake caliper 101. As such, the stroke limiter 105 remains stationary with respect to the rotation of the brake caliper 101 and/or the support structure 104 along the axis 103. As the brake caliper 101 rotates along the axis 103, the distance between the stroke limiter 105 and a side of the brake caliper 101 diminishes. When the side of the brake caliper 101 comes into contact with the stroke limiter 105, an end 301 of the stroke 107 is reached. When the end 301 of the stroke 107 is reached, at least part of the brake torque from the brake caliper 101 is transferred to the frame 106. As such, the rotation of the brake caliper 101 along the axis 103 is limited by the interaction between the stroke limiter 105 and the brake caliper 101. The stroke limiter 105 ensures that at least part of the brake torque generated by the interaction between the brake caliper 101 and the brake disc 102 is transferred to the frame 106 when the end 301 of the stroke 107 is reached, such that further rotation of the brake caliper 101 and/or the support structure 104 is stopped.

Fig. 12a schematically shows a brake torque measuring system 110 according to an eighth embodiment of the invention and Fig. 12b schematically shows a detailed view of a brake torque measuring system 110 according to the eighth embodiment of the invention. The eighth embodiment is identical to any one of the embodiments described above, with the exception of the stroke limiter 105. The stroke limiter 105 in the eighth embodiment is an alternative for or additional to the stroke limiter 105 of any of the embodiments described above. In the embodiment shown in Figs. 12a-12b, the stroke limiter 105 is arranged on the frame 106. The stroke limiter 105 interacts with the force transducer 801. The force transducer 801 is arranged between the stroke limiter 105 and the brake caliper 101. As such, the stroke limiter 105 remains stationary with respect to the rotation of the brake caliper 101 and/or the support structure 104 along the axis 103. As the brake caliper 101 rotates along the axis 103, the distance between force transducer 801 and a side of the brake caliper 101 diminishes. When the side of the brake caliper 101 comes into contact with the force transducer 801, an end 301 of the stroke 107 is reached. When the end 301 of the stroke 107 is reached, at least part of the brake torque from the brake caliper 101 is transferred to force transducer 801, and indirectly to the stroke limiter 105 and the frame 106. As such, the rotation of the brake caliper 101 along the axis 103 is limited by the interaction between the force transducer 801 and brake caliper 101. The force transducer 801 ensures that at least part of the brake torque generated by the interaction between the brake caliper 101 and the brake disc 102 is transferred to the frame 106 when the end 301 of the stroke 107 is reached, such that further rotation of the brake caliper 101 and/or the support structure 104 is stopped. The force transducer 801 is for example a load cell for detecting brake torques during a brake action, i.e., it can withstand large forces.

Fig. 13 schematically shows a side view of a brake torque measuring system 110 according to a ninth embodiment of the invention. The ninth embodiment is identical to any one of the embodiments described above, with the exception of the means to rotatably connect the support structure 104 to the frame 106. The means to connect the support structure 104 to the frame 106 in the ninth embodiment is an alternative for or additional to the means to rotatably connect the support structure 104 to the frame 106 of any of the embodiments described above. In the embodiment shown in Fig. 13, the support structure 104 comprises a bearing 1301, wherein the bearing 1301 connects the brake caliper 101 to the frame 106. For example, the bearing 1301 is a rolling element bearing, a sliding bearing, or a fluid bearing, for example an air bearing. The bearing 1301 allows the brake caliper 101 to rotate along the axis 103, along the stroke 107, relative to the frame 106. The frame 108 is connected to the stationary part of the bearing 1301, while the support structure 104 is connected to the rotational part of the bearing 1301. As such, the bearing 1301 provides a degree of freedom to the brake caliper 101 along the axis 103 along the stroke 107.

Fig. 14 schematically shows a portion of a vehicle according to an embodiment of a further aspect of the invention. The vehicle is for example an automobile, e.g. a commercially available automobile for use on public roads. The vehicle is for example an at least partially electrically powered vehicle. The vehicle is for example an electrically powered vehicle, further comprising one or more solar panels for providing power. In Fig. 14, a body 1402 of a vehicle is shown, comprising a wheel housing 1401. A brake torque measuring system 110 according to the first aspect of the invention is integrated into the wheel housing 1401. The vehicle comprises a frame 106, which frame 106 in the shown embodiment is an upright of the vehicle. The upright 106 connects a wheel hub 1402 to the body of the vehicle, which wheel hub 1402 is configured to hold a wheel of the vehicle. Optionally, the wheel of the vehicle is powered, e.g., by an in-wheel motor. Optionally, the wheel is steerable. The upright 106 further connects the brake disc 102 to the body of the vehicle. In the shown embodiment in Fig. 14, the support structure 104 rotatably connects the brake caliper 101 to the upright 106 by three flexible hinges 108. The brake caliper 101 is configured to engage the brake disc 102 to create a brake force along the axis 103. For example, during driving of the vehicle, the driver of the vehicle and/or an automated system engages the brake caliper 101 to perform a brake action. The brake action slows down and/or stops the rotation of the brake disc 102 and/or the wheel hub 1402 and/or the wheel. For another example, residual brake drag is generated when no brake action is performed. The support structure 104 is arranged such that the brake caliper 101 rotates along the axis 103 along the stroke 107. A measuring unit 401 {not shown) is further arranged for measuring a quantity representative of the brake torque. Providing a support structure 104 that is adapted to rotatably connect the brake caliper 101 to the upright 106, allows to select a measuring unit 401 (not shown) that is optimized to measure the brake torque in a desired range. For example, the desired range is a range for measuring residual brake torques. For another example, the desired range is a range for measuring brake torques generated during a brake action. For another example, the desired range comprises the range for measuring residual brake torques and the range for measuring brake torques generated during a brake action.

Fig. 15 schematically shows a portion of a test system 1502 according to an embodiment of a further aspect of the invention. The test system 1502 comprises a motor

1501. The motor 1501 is configured to drive the brake disc 102, i.e., to rotate the brake disc 102 with a desired velocity along the axis 103. The rotation of the brake disc 102 mimics the functioning of the brake disc 102 as if it were integrated in a vehicle. The test system 1502 is for example configured such that the desired velocity is set by an operator of the test system

1502. For example, the operator is a test engineer who uses the test system 1502 to predict, optimize and/or calibrate the behavior of a brake system 201. The brake system 201 comprises the brake caliper 101, which brake caliper 101 is configured to engage the brake disc 102 to create a brake force along the axis 103. The test system 1502 comprises a frame 106, which frame 106 in the shown embodiment is a support platform of the test system 1502. The support structure 104 (not shown) rotatably connects the brake caliper 101 to the support platform 108 by a flexible hinge 108. Another perspective, wherein it is shown that the support structure 104 rotatably connects the brake caliper 101 to the support platform 106 is shown in Fig. 11a. The support platform 106, relative to the brake caliper 101, provides a neutral reference position over which the brake caliper 101 can rotate along the axis 103 along the stroke 107. At the same time, the support platform 106 also provides a neutral reference position over which the brake disc 102 can rotate along the axis 103. A measuring unit 401 {not shown) is further arranged for measuring a quantity representative of the brake torque. Providing a support structure 104 that is adapted to rotatably connect the brake caliper 101 to the support platform 106, allows to select a measuring unit 401 (not shown) that is optimized to measure the brake torque in a desired range. For example, the desired range is a range for measuring residual brake torques. For another example, the desired range is a range for measuring brake torques generated during a brake action. For another example, the desired range comprises the range for measuring residual brake torques and the range for measuring brake torques generated during a brake action.

Claims

-29- CONCLUSIONS

A braking torque measurement system (110) for a vehicle braking system (201), the braking system (201) comprising a caliper (101) adapted to interact with a brake disc (102) to create a braking torque along an axis ( 103); the brake torque measurement system (110) comprising: a support structure (104) for supporting the brake caliper (101); a measurement unit (401) for measuring an amount representing the braking torque; a stroke limiter (105); wherein the support structure (104) is arranged to rotatably connect the caliper (101) to a frame (106), the support structure (104) being arranged to allow the caliper (101) to rotate relative to the frame (106 ) along the axis (103) over a stroke (107); wherein the stroke limiter (105) is provided at an end of the stroke (301); wherein the travel limiter (105) is configured to transmit at least a portion of the braking torque from the caliper (101) to the frame (106) when the caliper (101) is at the end of its travel (301).

The braking torque measuring system (110) according to claim 1, wherein the measuring unit (401) is arranged to measure the amount representing the braking torque based on a rotational position of the caliper (101) along the stroke (107).

The braking torque measuring system (110) according to claim 1 or 2, wherein the measuring unit (401) is arranged to measure the amount representing the braking torque within a measuring range, e.g. the measuring range is between 0-4 Nm, the stroke limiter (105 ) is provided to transmit at least part of the braking torque from the caliper (101} to the frame (106) only when the braking torque exceeds the measuring range.

The braking torque measurement system (110) according to any one of the preceding claims, wherein the support structure (104) comprises a bearing (1301), the bearing (1301) being arranged to rotatably connect the caliper (101) along the shaft (103) to the frame (106).

The braking torque measurement system (110) according to any of the preceding claims, wherein the support structure (104) comprises a flexible hinge (108), the

flexible hinge (108) is adapted to rotatably connect the caliper (101) along the axis (103) to the frame (106).

The braking torque measurement system (110) according to any of the preceding claims, wherein the stroke limiter (105) is mounted on the frame (108) to contact the brake caliper (101) at the end of the stroke (301).

The braking torque measurement system (110) of any one of claims 1 to 6, wherein the stroke limiter (105) is mounted on one of the support structure (104) and the frame (106) to transmit at least a portion of the braking torque from the caliper (101) on the frame (106).

The braking torque measurement system (110) according to any one of claims 1 to 6, wherein the stroke limiter (105) is mounted on one of the measurement unit (401) and the frame (106) to transmit at least a portion of the braking torque from the caliper (101) on the frame (108).

The braking torque measuring system (110) according to any of the preceding claims, wherein the measuring unit (401) includes a measure (601) for indicating the amount representing the braking torque.

The braking torque measuring system (110) according to any of the preceding claims, wherein the measuring unit (401) comprises a sensor (701, 801) for providing a signal representing the braking torque.

The braking torque measurement system (110) according to claim 10, wherein the sensor (701, 801) is a force transducer (801), for example a load cell or a strain gauge, mounted between the support structure (104) and the frame (106) or between the brake caliper ( 101) and the frame (106) to generate a force on the force transducer (801) based on the rotational position of the caliper (101) along the stroke (107).

The braking torque measurement system (110) of claim 10, wherein the sensor (701, 801) is a displacement sensor (701), the sensor (701, 801) being configured to sense an amount that indicates the rotational position of the caliper (101) along represents the stroke (107).

The braking torque measurement system (110) according to any one of claims 10-12, wherein the braking torque measurement system (110) comprises a signal processing unit (501), the signal processing unit (501) being configured to:

-31- receive the signal provided by the sensor (701, 801); process the signal to obtain a signal processing result; generate a communication signal representative of the signal processing result.

14. A vehicle comprising: a body (1402); a braking system (201) comprising a brake caliper (101) and a brake disc (102); and a braking torque measuring system (110) according to any one of claims 1-13; wherein the brake disc (102) is arranged to interact with the brake caliper (101) to create a braking torque along the axis (103); wherein the body (1402) includes the frame (106).

The vehicle of claim 14, wherein the frame (106) is a post for rotatably holding a wheel, the wheel being rotatable along the axis (103) relative to the post.

The vehicle according to any one of claims 14-15, wherein the vehicle comprises a number of braking torque measuring systems (110) equal to the number of wheels of the vehicle, and wherein the support structure (104) of each braking torque measuring system (110) is mounted around the caliper (101) of a corresponding wheel.

17. A brake test system (1502), comprising: a support platform (1501); a braking torque measuring system (110) according to any one of claims 1-13; wherein the support platform (1501) includes the frame (106).