WO2024261379A1

WO2024261379A1 - Electric trailer brake system and brake drum of electric trailer brake

Info

Publication number: WO2024261379A1
Application number: PCT/FI2024/050121
Authority: WO
Inventors: Aki KANKARE
Original assignee: Ak Usatrucks Oy
Current assignee: Ak Usatrucks Oy
Priority date: 2023-06-22
Filing date: 2024-03-15
Publication date: 2024-12-26
Anticipated expiration: 2025-12-22
Also published as: FI20235721A1

Abstract

Disclosed is an electric trailer brake system (200) comprising a brake drum (202) having an inner first surface (202A), and on circumference of brake drum an inner second surface (302), which is perpendicular to inner first surface which is circular shaped. The brake system includes a brake shield (204), an actuator arm (206) pivotably formed to brake shield. Actuator arm has an electromagnet (208) fastened to a first end (206A), electromagnet moves towards inner first surface to exert a force between electromagnet and inner first surface, when electromagnet is electrified, to move actuator arm in a direction of brake drum rotation from a resting position (502), to move a brake shoe (210), connected to actuator arm, to contact inner second surface to form a friction force.

Description

ELECTRIC TRAILER BRAKE SYSTEM AND BRAKE DRUM OF ELECTRIC

TRAILER BRAKE

TECHNICAL FIELD

The present disclosure relates to electric trailer brake system. Moreover, the present disclosure relates to brake drum of an electric trailer brake.

BACKGROUND

The electric trailer brake systems utilize an electrical connection between the towing vehicle and the trailer to activate the trailer brakes when the driver applies the brakes in the towing vehicle. The development of electric trailer brake systems has been limited by mechanical weaknesses in brakes. Because of this, their control systems must be quite primitive, which in practice are controlled manually by the driver. Due to the mechanical weaknesses of the brakes, controlling the electric trailer brakes can be inherently challenging and prone to difficulties. The electric trailer brakes are temperature sensitive, and the braking force is strongly non-linear. The non-linearity is increased by the fact that the frequency of the vibration caused by the spoke bolts is directly proportional to the rotational speed of the drum. In this regard, the vibration increases with increasing rotational speed and decreases with decreasing rotational speed. The brake works more efficiently when the rotational speed decreases thus the air gap of the magnet decreases as the rotational speed decreases and the vibration decreases, this increases nonlinearity and brakes become more efficient when driving speed decreases. The brakes wear out at different rates and are therefore affected by unwanted electrical phenomena (such as air gap, and inductance variation). The friction coefficient between the magnet and the friction surface of the magnet, which the magnet is in contact within, has not to be constant, it can change. Brake force varies greatly between brakes. Due to the high brake force throw and non-linearity, electric trailer brakes have to be used significantly underpowered in relation to the braking power of the towing vehicle in order to avoid unwanted wheel locking. The driver adjusts the brake force of the trailer wheel until the combination can be driven and throws, variations and nonlinearity of the brake force are not a problem.

Currently, manufacturers of electric trailer brakes use a friction material in their brake shoes that achieves soft brake behavior. The nature of the friction material provides lagging force. This is because the brakes are so non-linear and the braking force is so unstable, the soft friction material compensates for these factors, together with any pre-adjustment made on the basis of the driver's miscalculation, for unwanted wheel locking. In particular, the soft-gripping friction material of the brake shoes in a way protects any incorrect brake adjustments made by the driver from wheel locking. Consequently, the friction material demonstrates inadequate braking performance under high temperature conditions.

FIG. 1 illustrates a brake drum 100. As shown, the brake drum 100 having an inner first surface 104 and a second surface 102. The brake drum 100 comprises a plurality of rim mounting bolts (collectively referred as 106) on the inner first surface 104. The brake drum 100 is configured to hold a brake shoe, actuator arm, electromagnet and a spring therein. The inner first surface 104 is operable to allow the electromagnet to attach therewith. The second surface 102 is configured to allow the brake shoe to form contact when the brake is applied.

Therefore, it is clear from FIG. 1 the brake drum design is such that the rim mounting bolts are compressively fitted to the holes in the friction surface of the electromagnet. When the electromagnet always hits the hole, it makes change in the air gap and thus affects the inductance of the electromagnet's coil. The change in inductance momentarily affects the ability of the electromagnet coil to receive electric current. Notably, the magnitude of the current equals the strength of the magnet field of the electromagnet. This variation in current directly causes the magnetic field and thus the brake force to be tossed. Throwing the magnetic field makes the magnet to vibrate and, together with the spinning drum, creates harmonious multiples. The number of revolutions of the rotating drum is a determining factor with the frequency of the vibration. The brake vibrates more when the rotational speed increases. This increases the nonlinearity of the brake force. The strong vibration of the magnet causes the friction surfaces to wear even more unwell, which accelerates the growth of the air gap and thus harmful when used over the long run.

Also, the friction coefficient of the friction surfaces of the magnet changes due to vibration, the wear of material, the deterioration of material.

Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks.

SUMMARY

The aim of the present disclosure is to provide a system to stop trailer. The aim of the present disclosure is achieved by electric trailer brake system and brake drum of an electric trailer brake as defined in the appended independent claims to which reference is made to. Advantageous features are set out in the appended dependent claims.

Throughout the description and claims of this specification, the words "comprise" , "include", "have", and "contain" and variations of these words, for example "comprising" and "comprises" , mean "including but not limited to", and do not exclude other components, items, integers or steps not explicitly disclosed also to be present. Moreover, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a brake drum of prior art;

FIGs. 2A and 2B are a front view and perspective view of an electric trailer brake system, in accordance with an embodiment of the present disclosure;

FIG. 3 is a perspective view of the brake drum, in accordance with an embodiment of the present disclosure;

FIG. 4 is a perspective view of a disc, in accordance with an embodiment of the present disclosure; and

FIGs. 5A and 5B are a front view of a disc electric trailer brake system depicting the electromagnet in resting position and actuated position, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practising the present disclosure are also possible.

In a first aspect, the present disclosure provides an electric trailer brake system comprising: a brake drum having an inner first surface, and on the circumference of the brake drum an inner second surface, which is perpendicular to the inner first surface, which the inner first surface is circular shaped, a brake shield, an actuator arm pivotably formed to the brake shield, which the actuator arm has an electromagnet fastened to a first end of the actuator arm, which the electromagnet moves towards the inner first surface to exert a force between the electromagnet and the inner first surface, when the electromagnet is electrified, to move actuator arm in a direction of the brake drum rotation from a resting position, to move a brake shoe, connected to the actuator arm, to contact the inner second surface to form a friction force; wherein an area of the inner first surface which is overlapped during rotation of the brake drum, by the electromagnet, is a solid uniform surface.

The electric trailer brake system provides similar braking force to each brake shoe to control the wear thereof. Moreover, there are no more spoke bolt holes, thereby eliminating vibration that increases with rotational speed, and thus significantly corrects the nonlinearity of the electric brake. Their braking force is similar and increases equally among different wheel brakes. In addition, electrical phenomena are reduced (such as. remanence) that they no longer interfere with the operation of the brakes.

The actuator arm, pivotably formed to the brake shield, plays a crucial role in the system's functionality. It houses the electromagnet at one end and is connected to the brake shoe at the other end. When the electromagnet is electrified, it exerts a force on the actuator arm, causing it to pivot and move the brake shoe into contact with the inner second surface of the brake drum. This action generates the required friction force to slow down or stop the trailer. The synergy between the actuator arm, electromagnet, and brake shoe ensures efficient and responsive braking operation. The spring holds the actuator arm in the resting position when the electromagnet is not electrified. This ensures that the brake shoe remains disengaged from the inner second surface, allowing the trailer to roll freely.

In a second aspect, the present disclosure provides a brake drum of an electric trailer brake, wherein the brake drum is having an inner first surface acting as surface to be in contact with an electromagnet, and on the circumference of the brake drum an inner second surface acting as a surface to be in contact with a brake shoe to generate braking force, which inner second surface is perpendicular to the inner first surface, and which the inner first surface is circular shaped, and wherein the inner first surface is a solid uniform surface.

The inner first surface acting as the contact surface for the electromagnet enhances the efficiency and effectiveness of the brake system. When the electromagnet is energized, it moves towards the inner first surface, creating friction and generating braking force. The circular shape of the inner first surface ensures consistent contact with the electromagnet, promoting reliable and uniform braking performance. Moreover, the inner second surface on the circumference of the brake drum acts as the contact surface for the brake shoe. When the brake is engaged, the brake shoe presses against the inner second surface, generating the necessary braking force to slow down or stop the trailer. The perpendicular orientation of the inner second surface to the inner first surface allows for efficient transfer of braking force, ensuring reliable and responsive braking performance.

Throughout the present disclosure, the term "electric trailer brake system" as used herein refers to a braking system that is designed to activate the brakes on the trailer, to provide braking, and to slow down or stop the trailer. The electric trailer brake system comprises also the control system which controls the braking. The control system regulates and governs the braking process in a coordinated manner, ensuring effective and controlled deceleration or stopping of the trailer. The electric trailer brake is controlled with control systems thus, brake force can be pre-programmed. The electric brakes can be adapted to work in harmony with the towing vehicle with the same braking force. The driver no longer needs to pre-adjust the brakes. The electric trailer brake system is mounted on a hub of the trailer. The hub is the central part of the wheel assembly that connects the wheel to the axle. It provides a mounting point for the electric trailer brake system. Notably, a rotor is attached to the wheel by an axle of the trailer. The trailer is a non-motorized vehicle that is designed to be towed by a powered vehicle, such as a car, truck and the like. Beneficially, the trailer is used for transporting goods, equipment, and so forth. Typically, the electric trailer brake system is proportional braking capability, which activates based on the usage of the tow truck pedal. In this regard, as the trailer moves following the towing vehicle and the towing vehicle driver applies the brakes, then the electric trailer brakes respond accordingly, providing braking force that matches the intensity of brakes with the towing vehicle. In the system, the braking force of the trailer can be pre-programmed for all pedal positions and load conditions. The strong non-linearity characteristic of electric brakes has also been corrected for memory functions. To utilize the control systems effectively, it is imperative that the identified weaknesses of the mechanical brakes are addressed and rectified in the current release. This implies that the control systems are designed to operate optimally when the necessary modifications or improvements have been implemented in the mechanical braking system. By resolving the weaknesses, such as inadequate performance, inconsistency, or reliability issues, the control systems can then be employed to enhance the overall braking capabilities, providing improved control, stability, and safety. Therefore, the successful integration of control systems relies on the prior correction of the weaknesses associated with the mechanical brakes. The electric trailer brake system is utilized in vehicles, such as trucks, buses, trailers, and the like. Electric trailer brakes are also particularly used in passenger cars and small trailers.

The term "brake drum" refers to a cylindrical-shaped metal drum that is mounted on the hub and rotates with the wheels of the trailer and provides a surface for braking. The brake drum has a hollow design having a large open section in the centre to accommodate the wheel hub and axle. The brake drum has the inner first surface and the inner second surface. The inner first surface is the flat surface operably coupled with the hub. The inner first surface of the drum refers to the inner portion of the brake drum that faces the electromagnet (explained below) when the brakes are engaged. The inner first surface comes in contact with the electromagnet when energized during braking.

The inner second surface provides a surface for the brake shoe to press against, generating friction and slowing down or stopping the trailer. The brake shoe is a curved metal plate that is lined with friction material, typically made of organic, semi-metallic, ceramic materials and a combination thereof. The brake shoe is positioned inside the brake drum and generates the necessary friction to slow down or stop the trailer. When the driver applies the brakes, the brake shoe pushes outward against the inner second surface of the brake drum. The friction material on the brake shoes creates friction as it presses against the rotating brake drum, converting the kinetic energy of the wheel into heat energy and ultimately slowing down the trailer.

The brake drum houses two brake shoes, each with a friction lining made of a heat-resistant material. When the driver applies the brakes, causing the brake shoes press against the inner second surface of the brake drum. The resulting friction between the brake shoes and the brake drum creates a braking force, converting the kinetic energy of the rotating wheel into heat energy, effectively slowing down or stopping the vehicle. The friction material for brake shoes provides precise and aggressive braking force and does not fade when heated. The change in friction material also provides increased and precise braking force to electric brakes, thereby increases the performance, accuracy and heat resistance of electric brakes. The term "brake shield" as used herein refers to a metal plate that covers the brake system on the electric trailer. Notably, the brake shield is located inside the brake system and arranged behind the brake shoes opposite to the brake drum. In particular, the brake shield protects the components of the brake system from debris, dirt, and moisture. Additionally, the brake shield also helps in preventing corrosion and prolongs the life of the brake system. Optionally, the brake shield is fabricated from metal, non-metal, ceramics and the like. Herein the brake shield is fabricated from steel. In an embodiment, the brake shield directs the airflow through the rotor and helps to cool the brakes thereby helping to minimize the amount of heat that is transferred to the hub, which can cause premature wear or damage. In another embodiment, the brake drum can be cast like cooling fins that make the air flow better and cool the brake drum.

An electric trailer brake system comprises the actuator arm pivotably formed to the brake shield, term "actuator arm" as used herein refers to a mechanical link between the braking system and the brake shoe that translates the input force from the brake mechanism into the required pressure on the brake drum. The actuator arm is configured to convert the force generated by the brake system into a mechanical action that engages the brake shoes. The first end of the actuator arm has the electromagnet. The "electromagnet" refers to a coil of wire that becomes magnetized when an electric current is passed through the coil. The electromagnet is coupled to the actuator arm, allowing it to move in response to changes in the magnetic field. The inner first surface faces the interior of the brake drum. The electromagnet is positioned in close proximity to the inner first surface when the brake system is at rest. When the electric current is passes through the electromagnet, the electromagnet is electrified, generating the magnetic field. The magnetic field causes the electromagnet to move towards the inner first surface of the brake drum. As the electromagnet moves towards the inner first surface, it creates a force between the electromagnet and the inner first surface and thereby connect thereof. The said force is exerted in a direction that opposes the rotation of the brake drum. The electromagnet effectively pulls the actuator arm towards the inner first surface, initiating the braking process. When the electromagnet moves, it causes the actuator arm to pivot from its resting position to the actuating position. The actuator arm moves in the direction of the rotation of the brake drum, applying force to the brake shoes. The brake shoe is connected to the actuator arm. The actuator arm movement causes the brake shoe to contact the inner second surface of the brake drum. This contact between the brake shoe and the inner second surface creates a friction force that opposes the rotation of the brake drum. This friction force acts as the primary means of slowing down or stopping the rotation of the wheel of the trailer.

The actuator arm, electromagnet, and brake shield work in synergy to initiate and control the braking process. When the electromagnet is electrified, it creates a magnetic field that moves the actuator arm towards the inner first surface. This movement of the actuator arm causes the brake shoe to make contact with the inner second surface, generating the necessary friction force for effective braking. Beneficially, by utilizing the electromagnet and actuator arm mechanism, the brake system can provide precise control over the engagement of the brake shoes. The application of electric current to the electromagnet allows for quick and accurate modulation of the braking force.

In an embodiment, the brake system comprises a spring, the spring is fitted between the brake shoes to hold the actuator arm in the resting position when the electromagnet is not electrified. The spring exerts a force on the actuator arm, keeping it in the resting position. The resting position refers to the state in which the actuator arm is not engaged with the brake shoes, and the brake shoes are not in contact with the inner second surface of the brake drum. The purpose of the spring is to ensure that the actuator arm remains in resting position, keeping the brake shoes clear of the braking surfaces and having an adequate gap therebetween. By holding the actuator arm in the resting position, prevent unnecessary friction and wear on the brake shoe lining and allows the wheels of the trailer to rotate freely without brake shoe contact.

The force of spring acts in opposition to the force exerted by the electromagnet when it is electrified. When the electromagnet is energized, it generates the magnetic field that attracts the actuator arm towards the inner first surface of the brake drum. This movement of the actuator arm engages the brake shoes, causing them to make contact with the inner second surface of the brake drum, creating a friction force that slows down or stops the rotation of the wheel. When the electromagnet is no longer electrified, the force exerted by the spring prevails, returning the actuator arm to the resting position. This retraction of the actuator arm disengages the brake shoes from the brake drum, releasing the brakes and allowing the wheels to rotate freely again.

The spring is an elastic component or mechanism that could absorb, store and release energy through a change in shape. The spring is the locking mechanism that fastens the actuator arm in the resting position when the electromagnet is not electrified. Notably, the spring provides a high force output with minimal force requirements. It will be appreciated that the spring provides a force to retract the brake shoe after the application of the braking in the original position. The spring is fabricated from a metal i.e., copper, iron, beryllium, titanium, and the like. The metal alloys include for example stainless steel, carbon steel, chrome silicon (chromium and silicon alloy), chrome vanadium (chromium and vanadium alloy), elgiloy (cobalt, chromium and nickel alloy) phosphor bronze, brass, and the like. It will be appreciated that the spring could be fabricated from rubber and plastic for example plastic composites, polyphenylene sulfide, Acrylonitrile butadiene styrene (ABS), nylon, acrylic, polyamide-imide (PAI) and the like. Optionally, the spring fabricated from the steel is heat treated. The heat treatment process enhances the ability of the spring to withstand deformation and return to its original shape.

The area of the inner first surface that is overlapped by the electromagnet during the rotation of the brake drum is solid and uniform. The solid uniform surface ensures consistent and reliable contact between the electromagnet and the brake drum. The solid uniform surface means that there are no gaps, irregularities, or interruptions in the contact area. The solid uniform surface helps to maximize the magnetic force between the electromagnet and the brake drum, ensuring a strong and reliable attraction. By providing a solid uniform surface, the brake system minimizes the risk of any undesirable effects that could compromise the effectiveness of the braking action. Irregularities or gaps in the contact area could lead to reduced magnetic force, uneven engagement of the brake shoes, or unreliable braking performance. Therefore, having a solid uniform surface in the overlapped area enhances the stability and consistency of the braking action, contributing to safe and efficient braking performance.

Additionally, the solid uniform surface facilitates the efficient transfer of the magnetic force from the electromagnet to the brake drum. The solid uniform surface allows for a larger surface area of contact, ensuring that the force is evenly distributed and effectively transmitted to engage the brake shoes contributing to consistent friction between the brake shoes and the inner second surface of the brake drum, resulting in smooth and controlled braking performance.

Optionally, the inner first surface has a solid uniform surface outside of the area. In this regard, the solid uniform surface outside of the area ensures consistent and reliable contact between the electromagnet and the brake drum. By maintaining a smooth and uniform surface, the brake shoes can make reliable contact with the brake drum during the braking process thereby enhancing the frictional force and allowing for effective braking action. A technical effect of the inner first surface having the solid uniform surface outside is that it prevents uneven wear and tear on the brake drum, as well as promotes even distribution of the braking force, minimizing the hot spots or uneven friction, which can lead to premature wear or failure.

Optionally, the entire inner first surface is a solid uniform surface.

Optionally, the inner first surface is a first surface of a disc and the disc is attached to the brake drum. In this regard, the inner first surface is the first surface of the disc. The term "disc" as used herein refers to a flat, circular, rotating component that is directly attached to the brake drum. The disc is fabricated from a magnetic material. Optionally, the disc is fabricated from cast iron, composite, and the like. The disc is designed to rotate along with the wheel and is responsible for generating friction to slow down or stop the rotation of the wheel when the brakes are applied.

The disc and brake drum work in tandem to create the necessary friction for braking. The disc is securely attached to the brake drum to ensure that the braking force is effectively transmitted and enables the transfer of the braking force from the brake shoes to the drum and, subsequently, to the rotating wheel. Moreover, the heat transfers from the disc to the brake drum. The attachment of the disc to the brake drum provides stability and alignment during braking and prevents any slippage or misalignment.

Optionally, the disc is attached to the brake drum by fastening means. In this regard, to secure the disc in place, it is attached to the brake drum using fastening means. The fastening means may include bolts, screws, rivets, clamps or retaining clips and the like that firmly connect the disc to the brake drum. The fastening means ensures a stable and reliable connection between the disc and the brake drum.

Typically, the fastening means used to secure the disc to the drum and must be durable, and able to withstand the forces and stresses generated during braking. The fastening means are designed to provide sufficient clamping force to hold the disc firmly in place while allowing for the necessary rotation during operation. A technical effect of attaching the disc to the brake drum by fastening means is that it prevents any unwanted movement or misalignment that could result in uneven braking, noise, or premature wear and also promotes smooth and stable operation.

Optionally, the disc is attached to the brake drum by form-locking or press-locking. In this regard, the form-locking involves interlocking features on the disc and brake drum that create a secure and precise connection. Suitably, the said features can be tabs, grooves, or keyways that fit together, creating a tight and reliable bond between the disc and the brake drum. It will be appreciated that the interlocking design prevents rotational or lateral movement between the disc and brake drum, ensuring that both function as a single unit during braking. Beneficially, the form-locking provides stability and alignment, allowing for efficient transfer of braking force and consistent performance. Moreover, the press-locking involves using pressure to secure the disc to the brake drum. The press-locking is achieved by the use of retaining bolts or screws. The disc is positioned on the drum, and the retaining bolts or screws are tightened to exert pressure, clamping the disc and brake drum. The pressure exerted creates a firm and tight connection, preventing any relative movement between the disc and brake drum.

A technical effect of attaching the brake drum and the disc by formlocking or press-locking is that it provides a secure attachment between the disc and brake drum, ensuring that the brake drum and the disc work in connection to generate the necessary braking force and eliminate any play or looseness therebetween.

Optionally, the inner first surface is machined. The term "machined" as used herein refers to a process of shaping or finishing a material by using various cutting tools and techniques. In this regard, the inner first surface has undergone machining operations to achieve specific dimensions, smoothness, and accuracy. In an embodiment, the inner first surface is machined using a machine or tools (such as a lathe, milling machine, grinding equipment and so forth). Typically, the machining process removes excess material and creates the desired shape and finish on the inner first surface to ensure the inner first surface is precise, flat, and free from any imperfections or irregularities that could affect its performance. Optionally, the term machined can also mean that the inner first surface undergoes machining by a braking (brake-in) procedure. The faster the brake-in procedure is, the faster the braking force is in an optimal operating level, and the heat transfer is also in an optimal range. The machining of the inner first surface helps also to speed up the brakein procedure.

The machining process ensures uniformity, consistency, and tight tolerances for optimum braking performance. A technical effect of machining the inner first surface is that it promotes efficient and consistent contact between the electromagnet and the inner first surface during braking to reduce frictional losses. It will be appreciated that the machining allows the removal of surface defects, such as burrs, rough spots, or unevenness to improve the reliability, durability, and longevity of the brake system. The grinding (type of machining process) allows the inner first surface contact mating surfaces to achieve a high level of precision and tight fit. The machining result, combined with the run-in phase, allows different part to reach their intended level of functionality and performance. This contributes to the longevity and efficiency of the system by ensuring that the mating surfaces work harmoniously and experience minimal wear during the initial stages of operation.

Optionally, the inner first surface is patterned. The term "patterned" as used herein refers design or texture applied to the surface. Typically, the patterned process involves creating a series of raised or recessed features on the inner first surface, in a regular or repeating manner. For example, the pattern may be designed to improve the frictional characteristics between the braking system, such as between the magnet and the inner first surface. The raised or recessed features on the inner first surface create additional points of contact, increasing the grip and enhancing the braking efficiency.

A technical effect of patterning the inner first surface is that it can result in improved stopping power, shorter braking distances, and better overall braking performance. Optionally, patterning on the inner first surface can help with heat dissipation. For example, by creating channels or grooves on the inner first surface, heat generated during braking can be more effectively dispersed, preventing excessive heat build-up and thereby reducing the risk of overheating. Additionally, the channels or grooves on the inner first surface may be used for the removal of brake dust therefrom.

Optionally, the inner second surface is grooved. The term "grooved" refers to a surface feature having a series of channels that are created on the surface. Typically, the grooves are cut or machined into the inner second surface, forming a pattern of parallel or intersecting lines. The grooving enables the evacuation of debris, dust, water, and gases that can accumulate between the brake shoe and the inner second surface. The grooves act as channels that help channel these substances away, preventing them from interfering with the contact and friction between the braking components. A technical effect of grooving is that it enhances the bite or grip of the brake shoes on the inner second surface, resulting in better braking performance and increased safety.

Optionally, a material of the brake drum is iron, cast iron, spheroidal graphite cast iron, flake graphite or a combination of the aforementioned. In this regard, the brake drum is fabricated from iron, cast iron, spheroidal graphite cast iron, flake graphite and a combination thereof. The material for the brake drum is chosen in such a way that contributes to the performance, heat dissipation, wear resistance, and overall reliability of the brake drum in various braking applications. The selection of the material depends on factors such as the intended use, load capacity, and desired performance characteristics of the brake system. In an embodiment, the brake drum may be fabricated from the Acrylonitrile Butadiene Styrene (ABS).

Optionally, the disc is a different material than the material of the brake drum. In this regard, the disc and the brake disc are fabricated from distinct materials. The brake drum is typically made of materials such as iron, cast iron, or spheroidal graphite cast iron, as mentioned previously. On the other hand, the disc is made of materials like cast iron, carbon composite, or sometimes a combination of multiple materials.

The use of different materials allows optimal performance and efficiency of the braking system. The disc is exposed to intense friction and heat during braking, and different materials can provide specific characteristics to handle these conditions effectively. For example, carbon composite discs offer excellent heat dissipation and reduce the risk of brake fade, making them suitable for high-performance or heavy- duty applications. Moreover, the choice of different materials for the disc and brake drum can help in managing weight distribution and reducing overall weight in the braking system. By using lighter materials for the disc, such as carbon composite, to reduce mass, leading to improved handling and fuel efficiency. The disc and brake drum materials are chosen to ensure compatibility, durability, and optimal performance when they interact during the braking process.

Optionally, the inner first surface is coated. In this regard, a layer of material has been applied to the inner first surface for protection, improved functionality, and so forth. The coating of the inner first surface provides a protective barrier against external elements, such as moisture, chemicals, or debris. This protective layer shields the inner first surface from corrosion, oxidation, and other forms of degradation that can occur over time. By preventing direct contact with potentially harmful substances, the coating helps to preserve the integrity of the surface.

Furthermore, the coating can enhance the surface properties of the inner first surface. The coating may improve characteristics such as hardness, smoothness, or friction coefficient, depending on the specific coating material and application process. The improved characteristics can lead to improved performance and durability of the surface within the intended system or mechanism. For example, in the brake system, a coated surface may exhibit reduced friction, better wear resistance, or improved heat dissipation, resulting in more efficient and reliable braking.

Optionally, the inner first surface is coated with a nanocoating. In this regard, the nanocoating refers to a thin layer of protective material, applied to the inner first surface using nanotechnology. Typically, the nanocoating consists of nanoparticles, ranging from 1 nanometre to 100 nanometres. The nanocoating of the inner first surface provides protection, and durability, against environmental factors, including moisture, chemicals, and oxidation. The nanocoating forms a thin, invisible layer that adheres to the surface, creating a shield against corrosive elements. The shield helps to prevent rust, corrosion, and degradation of the inner first surface, ensuring its longevity and optimal functioning within the brake system.

Moreover, the nanocoating can improve the surface properties of the inner first surface such as hardness, scratch resistance, and wear resistance, providing a protective layer that can withstand the friction and mechanical forces experienced during braking. Optionally, the nanocoating may be hydrophobic or oleophobic having water, oil, and dirt particles repelling characteristics. A technical effect of nanocoating is that the nanocoating acts as a barrier against environmental factors, improves surface properties, and offers self-cleaning properties.

Optionally, the material of the brake drum or the disc is of an annealed and/or heat-treated material. In this regard, a heat treatment process has been applied to enhance the properties and performance of the material of the brake drum. Typically, annealing involves heating the material to a specific temperature and then gradually cooling it to room temperature. This process relieves internal stresses, improves ductility, and refines the grain structure of the material. In particular, annealing helps to enhance the material's machinability, formability, and overall mechanical properties, making it easier to shape and work with during the manufacturing process. Furthermore, the heat treatment involves heating the material to a specific temperature and then rapidly cooling it to alter its microstructure. This process can increase the material's hardness, strength, and resistance to wear and deformation. Suitably, the heat treatment can also improve the toughness and durability of the material, enabling it to withstand the high stresses and temperatures experienced during braking. A technical effect of subjecting the brake drum or the disc material to annealing and/or heat treatment is that the performance of the material is optimized for its intended function in the braking system. The annealed or heat-treated material exhibits improved strength, wear resistance, and thermal stability, ensuring reliable and consistent braking performance under various operating conditions.

The present disclosure also relates to the brake drum as described above. Various embodiments and variants disclosed above, with respect to the aforementioned electric trailer brake system, apply mutatis mutandis to the brake drum.

Optionally, the inner first surface is a first surface of a disc and the disc is attached to the brake drum.

Optionally, the brake drum of an electric trailer brake further comprises an anti-lock braking system (ABS) ring, wherein the ABS ring is integrated or machined on the inner first surface. The term "ABS ring" refers to a toothed or slotted ring made of metal, typically steel or magnetic material, and is mounted on a rotating component (herein such as on a wheel hub). The ABS ring provides rotational speed information to the ABS. Typically, the ABS ring has a plurality of evenly spaced teeth around its circumference. As the wheel rotates, the teeth or slots pass by a sensor known as the ABS sensor. The ABS sensor detects the passing teeth and generates electrical signals that are sent to the ABS control unit. By analysing the frequency and pattern of these signals, the ABS control unit can monitor the speed and rotation of each wheel. The signal information utilised by the ABS detects any wheel lock-up or skidding during braking and enables the system to modulate brake pressure for each wheel independently. A technical effect of using the ABS ring is that the implementation of the ABS ring provides information about the rotational speed of a wheel and prevents wheel lock-up during braking, improving vehicle stability and control.

The ABS ring is integrated on the inner first surface. In this regard, the ABS ring is incorporated into the surface itself by embedding the ABS ring within the material of the component during its manufacturing or assembly process. By integrating the ABS ring, it becomes an intrinsic part of the component, ensuring a secure and reliable connection. The ABS ring is machined on the inner first surface. In this regard, the ABS ring is created or carved into the surface of the component using machining techniques. This process involves removing material from the component's surface to precisely shape the ABS ring pattern. Machining ensures accurate placement and alignment of the ABS ring, enabling it to function correctly and provide accurate wheel speed information.

Optionally, the teeth of the ABS ring can be machined directly into the brake disc. In this regard, there is no need for a separate ABS ring. The ABS ring itself is integrated into the brake drum with a fastening system such as screws and bolts, rivets, clamps, clips, snap-fit and the like.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIGs. 2A and 2B, illustrated are a front view and perspective view of an electric trailer brake system 200, respectively, in accordance with an embodiment of the present disclosure. The electric trailer brake system 200 comprises a brake drum 202 having an inner first surface 202A, and on the circumference of the brake drum 202 an inner second surface (as shown in FIG. 3), which is perpendicular to the inner first surface 202A. As shown in FIG. 2A, the inner first surface 202A is circular shaped. Referring to FIG. 2B, there is shown a brake shield 204. The brake shield 204 protects the components of the brake system from debris, dirt, and moisture.

The electric trailer brake system 200 includes an actuator arm 206 pivotably formed to the brake shield 204. The actuator arm 206 has an electromagnet 208 fastened to a first end 206A of the actuator arm 208. During operation, the electromagnet 208 moves towards the inner first surface 202A to exert a force between the electromagnet 208 and the inner first surface 202A, when the electromagnet 208 is electrified, to move actuator arm 206 in a direction of the brake drum 202 rotation from a resting position, to move a brake shoe 210, connected to the actuator arm 206, to contact the inner second surface 202B to form a friction force.

The electric trailer brake system 200 includes a spring 212 arranged between the brake shoes 204 to hold the actuator arm 206 in the resting position when the electromagnet 208 is not electrified. Notably, the area of the inner first surface 202A which is overlapped during rotation of the brake drum 202, by the electromagnet 208, is a solid uniform surface. The inner first surface 202A is a first surface of a disc (as shown in FIG. 4) and the disc is attached to the brake drum 202. The disc is attached to the brake drum 202 by, fastening means 214 (such as a bolt).

Referring to FIG. 3, illustrated is a perspective view of the brake drum 202, in accordance with an embodiment of the present disclosure. As shown, the brake drum 202 having inner first surface 202A and inner second surface 302. The brake drum 202 comprises plurality of first apertures 304A-F (Herein, 304A, 304B and 304C are visible) on the inner first surface 202A configured to attach a disc (as shown in FIG. 3). The brake drum 202 is configured to hold the brake shoe, actuator arm, electromagnet and the spring (as shown in FIG. 1) therein, in conjunction with the disc. The inner first surface 202A is operable to allow the electromagnet to attach therewith. The inner second surface is 302 is configured to allow the brake shoe to form contact when brake is applied.

Moreover, the brake drum 202 further comprises an anti-lock braking system (ABS) ring 306. The ABS ring is integrated or machined on the inner first surface 202A.

Referring to FIG. 4, illustrated is a perspective view of a disc 400, in accordance with an embodiment of the present disclosure. The disc 400 is configured to attach the electromagnet when actuated. The disc 400 comprises a hollow opening 402 in the centre. The hollow opening 402 has a diameter (for example, depicted using a letter D), wherein said diameter may lie in a range of 90 mm to 200 mm. The disc 400 further comprises a plurality of second apertures 404A-F complimentary to the plurality of first apertures 304A-F of the brake drum 202. The plurality of second apertures 404A-F has a diameter (for example, depicted using a letter d), wherein said diameter may lie in a range of 5 mm to 10 mm. The disc 400 has a thickness (for example, depicted using a letter T), wherein said thickness may lie in a range of 1 mm to 7 mm.

Referring to FIGs. 5A and 5B, illustrated are a front view of a disc electric trailer brake system 200 depicting electromagnet 208 in resting position and actuated position, respectively, in accordance with an embodiment of the present disclosure. As shown in FIG. 5A, the electromagnet 208 is in the resting position 502. When brake pedal is applied the electromagnet 208 is actuated and moves from the resting position 502 to the actuated position 504. The actuator arm 206 is configured to move the electromagnet 208 from the resting position 502 to the actuated position 504. During the actuated position 502 the brake shoe 210 makes a contact with the inner second surface to stop the trailer. Moreover, the spring 212 is arranged to hold the actuator arm 206 in the resting position 502. When electric current is passed through the electromagnet 208 it securely attached to the inner first surface 202A, allowing the electromagnet 208 to move in response to changes in the magnetic field. When the supply of the electric current is stopped the electromagnet 208 detaches from the inner first surface 202A, and the spring 212 is configured to move the actuator arm 206 from the actuated position 504 to the resting position 502.

Claims

1. An electric trailer brake system (200) comprising: a brake drum (202) having an inner first surface (202A), and on the circumference of the brake drum an inner second surface (302), which is perpendicular to the inner first surface, which the inner first surface is circular shaped, characterized in that, a brake shield (204), an actuator arm (206) pivotably formed to the brake shield, which the actuator arm has an electromagnet (208) fastened to a first end (206A) of the actuator arm, which the electromagnet moves towards the inner first surface to exert a force between the electromagnet and the inner first surface, when the electromagnet is electrified, to move actuator arm in a direction of the brake drum rotation from a resting position (502), to move a brake shoe (210), connected to the actuator arm, to contact the inner second surface to form a friction force; wherein an area of the inner first surface which is overlapped during rotation of the brake drum, by the electromagnet, is a flat solid uniform surface, and wherein a material of the brake drum (202) is iron, cast iron, spheroidal graphite cast iron, flake graphite or a combination of the aforementioned.

2. An electric trailer brake system (200) according to claim 1, wherein the inner first surface (202A) has solid uniform surface outside of the area.

3. An electric trailer brake system according to claim 1 or 2 wherein the inner first surface (202A) is a first surface of a disc (400) and the disc is attached to the brake drum (202).

4. An electric trailer brake system (200) according to claim 3 wherein the disc is attached (400) to the brake drum (202) by fastening means (214).

5. An electric trailer brake system (200) according to claim 3 or 4 wherein the disc (400) is attached to the brake drum (202) by form-locking or press-locking.

6. An electric trailer brake system (200) according to any of the preceding claims wherein the inner first surface (202A) is machined.

7. An electric trailer brake system (200) according to any of the preceding claims wherein the inner first surface (202A) is patterned.

8. An electric trailer brake system (200) according to any of the preceding claims wherein the inner second surface (302) is grooved.

9. An electric trailer brake system (200) according to claim 1 wherein the disc (400) is a different material than the material of the brake drum (202).

10. An electric trailer brake system (200) according to any of the preceding claims wherein the inner first surface (202A) is coated.

11. An electric trailer brake system (200) according to claim 10 wherein the inner first surface (202A) is coated with a nanocoating.

12. An electric trailer brake system (200) according to any of the preceding claims wherein the material of the brake drum (202) or the disc (400) is of an annealed and/or heat-treated material.

13. A brake drum (202) of an electric trailer brake, characterized in that the brake drum is having an inner first surface (202A) acting as surface to be in contact with an electromagnet (208), and on the circumference of the brake drum an inner second surface (302) acting as a surface to be in contact with a brake shoe (210) to generate braking force, which inner second surface is perpendicular to the inner first surface, and which the inner first surface is circular shaped, and wherein the inner first surface is a flat solid uniform surface.

14. A brake drum (202) of an electric trailer brake according to claim 13, wherein the inner first surface (202A) is a first surface of a disc (400) and the disc is attached to the brake drum.

15. A brake drum (202) of an electric trailer brake according to claims 13 and 14, further comprises an anti-lock braking system (ABS) ring (306), wherein the ABS ring is integrated or machined on the inner first surface.