Description:Technical field of the invention
[0002] The present invention relates to an assembly for thermal management of hub motors. More specifically, the invention relates to an assembly for thermal management of a Brushless Direct Current (BLDC) hub motor used in electric vehicles, wherein a combination of thermal adhesive tape, thermal paste, heat sink, and connecting tape allows efficient dissipation of heat, prevent overheating, and extend motor lifespan without requiring any structural modifications to the motor housing.
Background of the invention
[0003] Brushless Direct Current (BLDC) hub motors are increasingly being adopted in different Electric Vehicles (EVs) such as e-bikes, e-scooters, and light electric two-wheelers, owing to their high efficiency, compact form factor, and minimal maintenance requirements. The architecture of the hub motor simplifies the drivetrain and improves overall energy efficiency. However, the compact integration creates challenges related to thermal management, particularly during the high-load conditions or the continuous-duty cycles.
[0004] During an extended operation or in scenarios involving steep gradients, rapid acceleration, or heavy payload transport, significant thermal buildup occurs within the BLDC hub motors. The primary sources of heat generation include resistive losses in the stator windings, magnetic core losses, and mechanical friction. Proper dissipation of the accumulated heat is essential to maintain consistent motor performance, to avoid thermal degradation of internal components, and ensure long-term operational reliability. However, the sealed and space-constrained architecture of the hub motors restrict airflow and complicates the use of conventional cooling mechanisms. Various solutions such as air-cooled fins, liquid cooling jackets, or thermally conductive casings have been explored in the industry which has involved increased weight, added system complexity, or the need for substantial design alterations to the motor casing or the vehicle frame.
[0005] Further, various patent applications have attempted to address the challenges through different technological solutions. For instance, the patent application No. CN108933498B, titled “Thermally enhanced hub motor” discloses a configuration of a hub motor to provide improved thermal performance by utilizing materials with differing thermal conductivities. The hub motor comprises a stator made of steel and a central shaft, such as a mandrel and shaft combination, formed from a material with substantially higher thermal conductivity—such as aluminium. The arrangement enables heat transfer from the stator to an external heat sink through the shaft. The invention further discloses a method of manufacturing the hub motor, including extrusion and low-temperature joining techniques used to assemble the central spindle and shaft, thereby facilitating effective heat dissipation.
[0006] Patent application No. US10350109B1, titled “Flexible adhesive physio tape with cooling properties” discloses a kinesiology or physio tape designed to deliver thermodynamic cooling through an integrated endothermic mechanism. The disclosed invention comprises a multilayered structure including a first layer of flexible, adhesive, and porous fabric; a second adhesive layer configured for skin contact; and a third intermediate layer containing endothermic materials. These materials are arranged such that a breakable barrier separates reactive components, allowing the user to manually initiate a cooling effect by breaking the barrier to trigger an endothermic reaction. The tape materials may consist of a blend of cotton, latex, or nylon, while the cooling layer may include liquids or solid reactants, either sealed or interwoven, to achieve sustained cooling during physical therapy or athletic use.
[0007] Patent application No. US8188627B2, titled “Temperature protection device for brushless DC motor” discloses a thermal protection mechanism integrated into the casing of a plastic-encased brushless DC motor. The invention features a thermal fusing-type protector positioned within a dedicated depression formed on the motor casing, strategically located at the region expected to experience the highest temperature following the plastic encapsulation. The configuration enables thermal monitoring and responsive protection by allowing the protector to fuse upon excessive heat exposure. Furthermore, the architecture facilitates straightforward replacement of the fused protector, ensuring ease of maintenance and extended operational reliability of the motor.
[0008] Despite the advancements, there remains a need for a simple, cost-effective, lightweight, and easily applicable solution that improves heat dissipation without requiring major modifications of the motor housing assembly, thereby enhancing thermal efficiency without adding weight or power consumption of the vehicle, and is adaptable across various BLDC hub motor architectures.
Summary of the invention
[0009] The present invention addresses the limitations of the prior art by disclosing a modular assembly for thermal management of a Brushless Direct Current (BLDC) hub motor that enables an efficient dissipation of heat without requiring structural modifications or electrical power consumption. The assembly comprises multiple heat sinks mounted on the outer casing of the BLDC hub motor for dissipating heat into the surrounding environment. Each heat sink is positioned over a thermal tape that functions both as a thermally conductive interface and an adhesive layer. A thermal paste is applied between the outer casing of the BLDC hub motor and the thermal tape to eliminate microscopic air gaps and enhance thermal conduction from the outer casing of the BLDC hub motor to the heat sinks.
[0010] Further, a connecting tape interlinks the heat sinks to one another, thereby ensuring thermal continuity and allowing modular scalability of the assembly based on the requirements of the thermal load.
[0011] The assembly offers a lightweight, compact, and universally compatible solution that integrates with different configurations of BLDC hub motors and eliminates the need for powered cooling assembly or invasive mechanical fixtures. The assembly further offers a cost-effective and passive thermal management solution that improves motor efficiency, reduces peak operating temperature, and extends the operational life of the BLDC hub motor.
Brief description of the drawings
[0012] The foregoing and other features of embodiments will become more apparent from the following detailed description of embodiments when read in conjunction with the accompanying drawings. In the drawings, like reference numerals refer to like elements.
[0013] Figure 1 illustrates a line diagram of a front view of a modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, in accordance with an embodiment of the invention.
[0014] Figure 2 illustrates a line diagram of a top view of the modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, in accordance with an embodiment of the invention.
[0015] Figure 3 illustrates a line diagram of an isometric view of the modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, in accordance with an embodiment of the invention.
Detailed description of the invention
[0016] In order to more clearly and concisely describe and point out the subject matter of the claimed invention, the following definitions are provided for specific terms, which are used in the following written description.
[0017] The term “Modular” refers to a scalable arrangement allowing the addition or removal of components such as heat sinks without modifying the BLDC hub motor.
[0018] The term “Outer Casing” refers to the external surface of the BLDC hub motor used for mounting the thermal management assembly.
[0019] The term “Thermal Continuity” refers to an uninterrupted and consistent conduction of heat across multiple interconnected heat sinks using the connecting tape to ensure uniform temperature dissipation along the surface of the outer casing of the BLDC hub motor.
[0020] The present invention relates to a assembly for thermal management of a Brushless Direct Current (BLDC) hub motor, comprising a modular arrangement of heat sinks, thermal tape, thermal paste, and connecting tape to passively dissipate heat from the motor surface without requiring structural modifications or electrical power.
[0021] Figure 1 illustrates a line diagram of a front view of a modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, in accordance with an embodiment of the invention. The assembly (100) comprises multiple heat sinks (102) disposed on an outer casing (101) of the BLDC hub motor. In an embodiment, the heat sinks (102) are constructed from a thermally conductive, lightweight metal aluminium that helps in dissipating the heat into the surrounding environment through the process of convection. The heat sinks (102) form the outermost layer of the thermal management assembly (100) and are structured to maximize the surface area of the heat sink as more area dissipates more amount of heat, thereby enhancing the efficiency of the passive heat dissipation from the BLDC hub motor.
[0022] Further, each of the heat sink (102) is thermally and mechanically coupled to the outer casing (101) of the BLDC hub motor by means of a thermal tape (103) interposed between the heat sink (102) and the outer casing (101) of the BLDC hub motor. The thermal tape (103) facilitates the conduction of heat from the outer casing (101) to the heat sink (102), and provides adhesive bonding for the mechanical attachment for securing the heat sink (102) in position. The thermal tape (103) conforms to the outer casing (101) of the BLDC motor and allows for simple, tool-free installation of the heat sinks (102) without requiring screws, or fasteners, and does not require any modifications to the structure of the BLDC hub motor.
[0023] Furthermore, the assembly (100) comprises a thermal paste (104) interposed between the outer casing (101) of the BLDC hub motor and the thermal tape (103). In an embodiment the thermal paste (104) is a silicone-based or metal-oxide-enhanced composition that enhance thermal conductivity between the outer casing (101) of the BLDC hub motor and the thermal tape (103). The thermal paste (104) eliminates the microscopic air gaps and surface irregularities of the outer casing (101) of the BLDC hub motor, thereby ensuring enhanced thermal conduction between the outer casing (101) and the thermal tape (103). The inclusion of the thermal paste (104) improves the efficiency and reliability of heat transfer from the BLDC hub motor to the external surrounding environment.
[0024] Additionally, the assembly (100) comprises a connecting tape (105) disposed below the of heat sinks (102) to mechanically and thermally interlink the heat sinks (102), thereby enabling thermal continuity across the array of the heat sinks (102) and ensuring uniform dissipation of heat. The connecting tape (105) further imparts structural integrity to the assembly (100) by stabilizing the position of the heat sinks (102) under mechanical stress or vibration.
[0025] Figure 2 illustrates a line diagram of a top view of the modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, in accordance with an embodiment of the invention. The assembly (100) is mounted on the outer casing (101) of the BLDC hub motor, that serves as the thermally active surface onto which the assembly (100) is externally affixed. The assembly (100) comprises multiple heat sinks (102) arranged along the length of the outer casing (101) of the BLDC hub motor to absorb and dissipate heat into the ambient environment through the process of convection. The heat sinks (102) are lightweight and compact in structure to facilitate thermal management without altering the form factor of the BLDC hub motor.
[0026] Further, the connecting tape (105) extends across and interconnecting adjacent heat sinks (102). The connecting tape (105) is thermally conductive, structurally flexible, provides thermal continuity across the heat sinks (102) and maintains the relative alignment during the operation of the BLDC hub motor.
[0027] Furthermore, the modular configuration of the heat sinks (102) and the connecting tape (105) allows for scalable installation along the outer casing (101) of the BLDC hub motors of different sizes or thermal requirements without any mechanical fasteners or structural modifications.
[0028] Figure 3 illustrates a line diagram of an isometric view of the modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, in accordance with an embodiment of the invention. The assembly (100) comprises the heat sinks (102) disposed circumferentially along the outer casing (101) of the BLDC hub motor to dissipate heat into the surrounding environment through the process of convection wherein each of the heat sinks (102) is formed of thermally conductive material with an increased surface area for improved thermal dissipation.
[0029] Further, each of the heat sinks (102) is mounted over the thermal tape (103) that facilitates the transfer of heat from the underlying outer casing (101) of the BLDC hub motor and secures the heat sinks (102) in position without any mechanical fasteners.
[0030] Furthermore, a layer of thermal paste (104) is interposed between the thermal tape (103) and the outer casing (101) of the BLDC hub motor to eliminate the microscopic air gaps and surface irregularities, thereby enhancing thermal conductivity between the outer casing (101) of the BLDC hub motor and the thermal tape (103).
[0031] Additionally, the thermally conductive and mechanically flexible connecting tape (105) extends across the heat sinks (102) to interconnect the heat sinks (102) for thermal continuity and to maintain their relative positioning during the operation of the BLDC hub motor.
[0032] The sequential layering of the thermal paste (104), thermal tape (103), heat sinks (102), and connecting tape (105) above the outer casing (101) of the BLDC hub motor forms a modular and scalable thermal management assembly suitable for BLDC hub motors of different sizes or thermal requirements without any structural modifications. The assembly further enables universal compatibility, making it adaptable to various BLDC motor.
[0033] The present invention offers significant advantages in the field of thermal management for Brushless Direct Current (BLDC) hub motors, particularly in applications such as electric two-wheelers, e-bikes, and other compact electric mobility system. The modular thermal management assembly (100) provides passive cooling without requiring electrical power or complex mechanical integration, thereby improving overall efficiency and reliability of the BLDC hub motor.
[0034] Further, the assembly (100) offers a lightweight and compact configuration that is externally mounted on the outer casing (101) of the BLDC hub motor without necessitating structural modifications or specialized tools. The use of the thermally conductive thermal tape (103) allows for tool-free installation and eliminates the need for fasteners, thereby reducing mechanical stress and simplifies the architecture of the assembly (100).
[0035] Furthermore, the modular arrangement enables customization of the number and placement of heat sinks (102) based on specific thermal load requirements. The interconnection of heat sinks (102) using a thermally conductive connecting tape (105) ensures thermal continuity and uniform heat dissipation across the outer casing (101) of the BLDC hub motor, allowing scalability and adaptability to different sizes and operating conditions of the BLDC hub motors.
[0036] Additionally, the integration of thermal paste (104), thermal tape (105), and heat sinks (102) establishes an efficient multi-layered thermal conduction path from the outer casing (101) of the BLDC hub motor to the surrounding environment that facilitates rapid heat transfer, reduces operating temperature, enhances the efficiency of the BLDC hub motor, and extends the operational lifespan by mitigating the risks associated with the thermal stress, such as a component degradation or a magnet demagnetization.
[0037] The assembly (100) provides an effective and power-free thermal management solution that supports sustained performance, long-term durability, and ease of application in diverse BLDC hub motor.
[0038] Having generally described this invention, a further understanding can be obtained by reference to specific examples, which are provided herein for the purpose of illustration only and are not intended to be limiting unless otherwise specified.
Example 1: Implementation of the modular thermal management assembly on a 250W BLDC hub motor in an electric bicycle
[0039] As an illustrative example, consider an electric bicycle that uses a 250W Brushless Direct Current (BLDC) hub motor and experiences elevated surface temperatures during uphill riding and prolonged low-speed operation, resulting in heat accumulation impacting its performance.
[0040] To solve the issue related to the heat accumulation, the modular thermal management assembly (100) is fixed on the outer casing (101) layer of the BLDC hub motor. Firstly a layer of thermal paste (104) is applied to the outer casing (101) to eliminate microscopic surface irregularities and improve thermal contact. Further, a thermally conductive adhesive tape (103) is affixed over the thermal paste (104), forming a thermally active and adhesive interface. Further, a set of four aluminium heat sinks (102), each measuring 50 mm × 20 mm × 5 mm, is mounted over the thermal tape (103) in a parallel configuration wherein a thermally conductive connecting tape (105) is positioned across the heat sinks (102) to interconnect them both thermally and mechanically, enabling uniform heat dissipation and structural stability.
[0041] The assembly (100) operates passively, without requiring electrical power. During the usage, the surface temperature of the BLDC hub motor is reduced by approximately 15%, leading to improved thermal regulation, reduced component stress, and extended operational life.
[0042] The entire assembly (100) is installed without any structural modification or the use of fasteners, demonstrating the ease of application and retrofitting capability across different BLDC motor used in different electric bicycle models.
Example 2: A scalable passive cooling application on a 500W BLDC hub motor in an electric scooter
[0043] In another example, the modular thermal management assembly (100) is fixed to a 500W BLDC hub motor integrated into an electric scooter for a delivery application. The BLDC hub motor of the assembly (100) frequently operates under high load conditions, including frequent start-stop usage and sustained low-speed travel, resulting in significant heat accumulation.
[0044] A uniform layer of thermal paste (104) is applied to the curved outer casing (101) of the motor and a flexible thermal tape (103) is fixed onto the paste-covered surface, allowing it to conform to the curvature of the motor housing (101). Further, six aluminium heat sinks (102), each measuring 60 mm × 25 mm × 6 mm, are mounted over the thermal tape (103) in a side-by-side configuration wherein a thermally conductive connecting tape (105) connects the lower surfaces of the heat sinks (102), providing structural cohesion and enabling thermal continuity along the array of the heat sinks (102).
[0045] Further, the assembly (100) is installed without any drilling, mechanical fastening, or electrical integration, making it suitable for field-level deployment and retrofitting. During the operation of the electric scooter, the maximum surface temperature of the BLDC hub motor is observed to decrease by approximately 14%, contributing to reduced thermal throttling and consistent power delivery. Further, the passive cooling arrangement of the assembly (100) ensures zero additional energy consumption and supports long-term durability of the BLDC hub motor used in the electric scooter.

Reference numbers:
Components Reference Numbers
Assembly 100
Outer Casing of the Brushless Direct Current (BLDC) Motor 101
Heat Sink 102
Thermal Tape 103
Thermal Paste 104
Connecting Tape 105
, Claims:We claim:
1. A modular thermal management assembly for a Brushless Direct Current (BLDC) hub motor, the assembly (100) comprising:
i. plurality of heat sinks (102) disposed circumferentially on an outer casing (101) of a BLDC hub motor for dissipating heat into a surrounding environment wherein the heat sinks (102) are structured to maximize surface area for increasing efficiency of a passive heat dissipation from the BLDC hub motor;
ii. a thermal tape (103) disposed between each of the heat sinks (102) and the outer casing (101) to facilitate thermal conduction from the outer casing (101) to the heat sinks (102) and provide adhesive bonding for securing the heat sinks (102) to the outer casing (101);
iii. a thermal paste (104) interposed between the thermal tape (103) and the outer casing (101) to fill one or more surface irregularities of the outer casing (101) and enhance thermal contact between the outer casing (101) and the thermal tape (103); and
iv. a connecting tape (105) disposed across the plurality of heat sinks (102) interlinking the heat sinks (102) to provide thermal continuity and mechanical alignment across the assembly (100);
wherein a sequential layering of the thermal paste (104), the thermal tape (103), the connecting tape (105) and the heat sinks (102) enables a passive, power-free thermal management of the BLDC hub motor without requiring mechanical fastening components or structural modifications to the housing of the BLDC hub motor.
2. The assembly (100) as claimed in claim 1, wherein the heat sinks (102) are constructed from thermally conductive, lightweight metals such as aluminium.

3. The assembly (100) as claimed in claim 1, wherein the thermal tape (103) comprises a flexible, pressure-sensitive adhesive layer with thermally conductive properties.

4. The assembly (100) as claimed in claim 1, wherein the connecting tape (105) is assembled to allow a modular expansion of the assembly (100) by enabling addition or removal of the heat sinks (102).

5. The assembly (100) as claimed in claim 1, wherein the thermal paste (104) is a silicone-based or metal-oxide-enhanced composition to ensure thermal conductivity.