BACK PRESSURE ADJUSTMENT FOR INDUCTOR COOLING

An inductor includes a bobbin defining a cavity, coils wound around the bobbin, and a plug inserted into the cavity. The plug and bobbin define a first fluid path between an inlet and the cavity. The plug is also arranged to choke flow of fluid through the first fluid path.

TECHNICAL FIELD

The present disclosure relates to automotive inductor cooling.

BACKGROUND

Automatic Transmission Fluid (ATF) is commonly used to cool different components of the transmission system. As such, balancing backpressure for each component may be necessary to deliver enough pressurized oil to each component. Different system applications, however, have different backpressure requirements for each component necessitating individual design and possible increasing design complexity and cost.

SUMMARY

An inductor includes a core, a bobbin surrounding the core and defining a cavity, coils wound around portions of the bobbin, and a plug inserted into the cavity. The bobbin defines fluid paths between an inlet and the cavity, and the cavity and the coils. The plug is in fluid communication with the fluid paths and chokes flow of fluid between the inlet and coils through the fluid paths.

An inductor includes a bobbin defining a cavity, coils wound around the bobbin, and a plug inserted into the cavity. The plug and bobbin define a first fluid path between an inlet and the cavity. The plug chokes flow of fluid through the first fluid path.

An inductor includes a core, coils surrounding portions of the core, a plug, and a bobbin overhanging the coils and defining a cavity that houses the plug such that portions of the plug and bobbin define a first fluid path between an inlet and the cavity. The plug chokes flow of fluid through the first fluid path.

DETAILED DESCRIPTION

As used in the specification and the appended claims, the singular form “a,” “an,” and “the” comprise plural references unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

The term “substantially” or “about” may be used herein to describe disclosed or claimed embodiments. The term “substantially” or “about” may modify a value or relative characteristic disclosed or claimed in the present disclosure. In such instances, “substantially” or “about” may signify that the value or relative characteristic it modifies is within ±0%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5% or 10% of the value or relative characteristic.

Vehicles that use a traction motor drive (electric machine or electric motor) for propulsion are referred to as electric vehicles (EVs). There are three main classes of electric vehicles. These three classes, which are defined by the extent of their electricity consumption, are namely Battery Electric Vehicles (BEV), Hybrid Electric Vehicles (HEV), and Plug-In Hybrid Electric Vehicles (PHEV). Battery electric vehicles generally use an external electrical grid to recharge their internal battery and power their electric motors. Hybrid electric vehicles use a main internal combustion engine and a secondary supplemental battery to power their motors. Plug-in hybrid electric vehicles, in contrast to hybrid electric vehicles, use a main large capacity battery and a secondary internal combustion engine to power their motors. Some plug-in hybrid electric vehicles can also run solely on their internal combustion engine without engaging the motors.

Electric vehicles typically include a voltage converter between the battery and the motor. Electric vehicles that entertain AC electrical current typically also include an inverter. Voltage converters may increase (boost) or decrease (buck) the voltage potential for enhancing performance of a traction motor drive. Voltage converters are normally comprised of a power inductor (reactor), diodes, and switches. The power inductor may comprise a conductive coil wounded around a magnetic core, which may be made from iron. The core may also be magnetized. Furthermore, one or more bobbin structures may be disposed between portions of the coil winding and the core.

The voltage converter and the inverter may be configured to deliver electrical power to the electric vehicle. This delivery of electrical power often results in heat generation which in turn necessitates a cooling system. Inductor cooling is commonly accomplished by mounting the inductor on a heat sink plate of an inverter system controller's aluminum housing, splashing fluid (typically transmission fluid) that acts as coolant onto the surface of the inductor, or flowing coolant in a conduit adjacent to the inductor. Accordingly, inductors may be cooled either actively or passively from the outside or the exterior of the inductor assembly. These methods, however, suffer from certain drawbacks.

Splashing transmission fluid onto the inductor via the internal gears within the transmission, for example, may not provide sufficient cooling as it is largely dependent on the vehicle speed. More specifically, high vehicle speed results in a high rotational speed of gears which in turn will be splashing the transmission fluid onto the inductor. However, under low vehicle speeds, where the gears within the transmission will be splashing the transmission fluid at a low rotational speed, the transmission fluid may not reach the inductor or a reduced amount of transmission fluid may reach the inductor, resulting in a reduction in the cooling of the inductor. Similarly, in other cooling methods, the transmission fluid may not have enough pressure to effectively cool down the inductor as it flows through a conduit adjacent to the inductor.

A solution to such a problem may include spraying pressurized transmission fluid from a nozzle onto targeted cooling surfaces of the inductor. The inlet or outlet of the inductor nozzle design can be modified to tune the back pressure to support different system applications. This method, however, may substantially increase the number of parts, complexity, and costs because it necessitates individual design for each component of the transmission system as each part may have a different backpressure requirement. Accordingly, there is a need to adjust back pressure, based on each system application, without having to substantially increase the number of parts, complexity, and costs.

Referring toFIGS.1-2, an inductor100for a voltage converter is illustrated.FIG.1illustrates a front view of the inductor100whileFIG.2illustrates a back view of the inductor100. The inductor100includes a core102, which may be made from iron. The core102may also be magnetized. The inductor100also includes a coil or coil winding104that is disposed about the core102. One or more bobbin structures106may be disposed around portions of the coil winding104and the core102surrounding the same. The one or more bobbin structures106may be disposed over a first end108, a second end110, or both ends of the inductor100. Alternatively, the one or more bobbin structures106may be a part of the core102of the inductor100. In such embodiments, the coil or coil winding104may be wound around portions of the bobbin106.

In some embodiments, the one or more bobbin structures106may define a cavity112(not shown inFIG.2). Furthermore, the bobbin106may define at least one fluid path114(not shown inFIG.1) between an oil inlet116(not shown inFIG.1) and the cavity112. Similarly, the bobbin106may define at least one fluid path114(not shown inFIG.1) between the cavity112and the coils104. In some embodiments, the bobbin106may define both fluid paths114between the oil inlet116and the cavity112and the cavity112and the coils104. In some embodiments, portions of the core102may form at least a part of the fluid paths114defined by the one or more bobbins106. In other words, the fluid paths114may be at least partially defined by the core102. For example, portions of the core102may form at least one side of the fluid paths114defined by the one or more bobbins106.

A plug118(not shown inFIG.2) may be inserted into the cavity112such that the plug118is in fluid communication with the fluid paths114and is configured to choke flow of fluid between the inlet116and coils104through the fluid paths114. Automatic Transmission Fluid (ATF) may be delivered to the inductor100via the fluid paths114for purposes of cooling the inductor100. In some embodiments, a pump (not shown) is configured to deliver ATF to the inductor100. More specifically, the pump, or any other means of oil delivery, may force ATF into the fluid paths114to cool the inductor100before exiting the fluid paths114via one or more oil outlets120. The one or more oil outlets120may be situated in the overhanging portion of the bobbin106such that they overhang the coil winding104.

FIG.3illustrates a cross sectional view of an inductor200. In particular, this exaggerated figure shows the flow direction of the ATF in some embodiments for the purpose of cooling down the inductor200. The inductor200shown in this figure comprises a core202and a coil or coil winding204that may be disposed around the core202. The inductor200may further comprise one or more bobbin structures206which may be disposed around portions of the coil windings204and the core202surrounding the same. The one or more bobbin structures206may be disposed over a first end208, a second end210, or both ends of the inductor200. Alternatively, the one or more bobbin structures206may be a part of the core202of the inductor200. In such embodiments, the coil or coil winding204may be wound around portions of the bobbin206. In some embodiments, the one or more bobbin structures206may define a cavity212, at least one fluid path214between an oil inlet216and the cavity212, and at least one fluid path214between the cavity212and the coils204. In some embodiments, the bobbin206may define both fluid paths214between an oil inlet216and the cavity212, and the cavity212and the coils204. In some embodiments, portions of the core202may form at least a part of the fluid paths214defined by the one or more bobbins206. In other words, the fluid paths214may be at least partially defined by the core202. For example, portions of the core202may form at least one side of the fluid paths214defined by the one or more bobbins206.

Inductor200may further comprise a plug218configured to form a seal upon insertion into the cavity212such that the plug218is in fluid communication with the fluid paths214and is configured to choke flow of fluid between the inlet216and coils204through the fluid paths214. Automatic Transmission Fluid (ATF) may be delivered to the inductor200via the fluid paths214for purposes of cooling the inductor200. In some embodiments, a pump (not shown), or any other means of oil delivery, may force ATF into the fluid paths214to cool the inductor200before subsequently exiting the fluid paths214via one or more oil outlets220. The one or more oil outlets220may be situated in the overhanging portions of the bobbin206such that they overhang the coil winding204.FIG.3demonstrated that the ATF may be fed to the inductor200via the oil inlet216where it travels through the at least one fluid path214between the oil inlet216and the cavity212, occupied by the plug218before traveling to the at least one fluid path214between the cavity212and the coils204. The fluid path214between the cavity212and the coils204may facilitate the cooling of the inductor200by causing the ATF to flow adjacent to the coils before and/or after the ATF exits the fluid path214via the one or more outlets220which may be situated in the overhanging portions of the bobbin206.

As mentioned above, depending on their application, different components of a transmission system have different backpressure requirements which may necessitate individual design to ensure delivery of enough pressurized oil to each component. The plug of the subject application is a mechanism that may be used to achieve the desired back pressure without substantially increasing cost, complexity, or number of parts. For example, the proposed plug may define a plurality of fins that obstruct the flow of fluid through the plug. These fins may have different shapes, dimensions, or configurations. In some embodiments, for example, the fins may have a tined configuration.

FIG.4illustrates a cross sectional view of an inductor300. The inductor300shown in this figure comprises a core302and a coil or coil winding304that may be disposed around the core302. The inductor300may further comprise one or more bobbin structures306which may be disposed around portions of the coil windings304and the core302surrounding the same. The one or more bobbin structures306may be disposed over a first end308, a second end310, or both ends of the inductor300. Alternatively, the one or more bobbin structures306may be a part of the core302of the inductor300. In such embodiments, the coil or coil winding304may be wound around portions of the bobbin306. In some embodiments, the one or more bobbin structures306may define a cavity312, at least one fluid path314between an oil inlet316and the cavity312, and at least one fluid path314between the cavity312and the coils304. In some embodiments, the bobbin306may define both fluid paths314between an oil inlet316and the cavity312and the cavity312and the coils304. In some embodiments, portions of the core302may form at least a part of the fluid paths314defined by the one or more bobbins306. In other words, the fluid paths314may be at least partially defined by the core302. For example, portions of the core302may form at least one side of the fluid paths314defined by the one or more bobbin306.

Inductor300may further comprise a plug318configured to form a seal upon insertion into the cavity312such that the plug318is in fluid communication with the fluid paths314and is configured to choke flow of fluid between the inlet316and coils304through the fluid paths314. Automatic Transmission Fluid (ATF) may be delivered to the inductor300via the fluid paths314for purposes of cooling the inductor300. In some embodiments, a pump (not shown), or any other means of oil delivery, may force ATF into the fluid paths314to cool the inductor300before subsequently exiting the fluid paths314via one or more oil outlets320. The one or more oil outlets320may be situated in the overhanging portions of the bobbin306such that they overhang the coil winding304.FIG.4demonstrated that the ATF may be fed to the inductor300via the oil inlet316where it travels through the at least one fluid path314between the oil inlet316and the cavity312, occupied by the plug318before traveling to the at least one fluid path314between the cavity312and the coils304. The fluid path314between the cavity312and the coils304may facilitate the cooling of the inductor300by causing the ATF to flow adjacent to the coils before and/or after the ATF exits the fluid path314via the one or more outlets320which may be situated in the overhanging portions of the bobbin306.

The plug318may further define a plurality of fins322that obstruct the flow of fluid. The fins322of the plug318may have different shapes, dimensions, or configurations. In the embodiment shown inFIG.4, for example, the fins322of the plug318, have different dimensions (length and thickness). In some embodiments, the fins322may have different lengths but the same thickness. In other embodiments, the fins322may have the same length but different thicknesses. In yet other embodiments, the fins322may have different lengths and thicknesses or the same lengths and thickness. Similarly, the fins322of the plug318may assume the same or different shapes. For example, in some embodiments, the fins322may be cylindrical, cubical, tined, or a combination thereof. The fins322of the plug318may also have different configurations. In some embodiments, for example, alternating ones of the fins322extend from opposite sides of the plug318toward an axial center thereof to define a tortuous path for the flow of fluid through the plug318. In other embodiments, the plug318further comprises a cap (not shown) wherein the fins322extend from the cap toward the fluid path314between the cavity312and the coils304. In some embodiments, the cap may be flush with an outer surface of the bobbin306.

Fins defined by the plug are not the only means of choking fluid flow to meet different design requirements—i.e., provide a sufficiently pressurized oil to different components of the transmission system to aid heat dissipation. In some embodiments, the plug may define a gap having a width less than a width of the fluid path between the cavity and coils. In other embodiments, the plug may define a serpentine fluid path wherein different parts of the serpentine fluid path have different lengths/widths. In yet other embodiments, the plug may define a bow or a cone shaped path to take advantage of the corresponding fluid mechanics principles that influence back pressure such as sudden expansion.

FIG.5illustrates a cross sectional view of an inductor400. The inductor400shown in this figure comprises a core402and a coil or coil winding404that may be disposed around the core402. The inductor400may further comprise one or more bobbin structures406which may be disposed around portions of the coil windings404and the core402surrounding the same. The one or more bobbin structures406may be disposed over a first end408, a second end410, or both ends of the inductor400. Alternatively, the one or more bobbin structures406may be a part of the core402of the inductor400. In such embodiments, the coil or coil winding404may be wound around portions of the bobbin406. In some embodiments, the one or more bobbin structures406may define a cavity412, at least one fluid path414between an oil inlet416and the cavity412, and at least one fluid path414between the cavity412and the coils404. In some embodiments, the bobbin406may define both fluid paths414between the oil inlet416and the cavity412, and the cavity412and the coils404. In some embodiments, portions of the core402may form at least a part of the fluid paths414defined by the one or more bobbin406. In other words, the fluid paths414may be at least partially defined by the core402. For example, portions of the core402may form at least one side of the fluid paths414defined by the one or more bobbins406.

Inductor400may further comprise a plug418configured to form a seal upon insertion into the cavity412such that the plug418is in fluid communication with the fluid paths414and is configured to choke flow of fluid between the inlet416and coils404through the fluid paths414. Automatic Transmission Fluid (ATF) may be delivered to the inductor400via the fluid paths414for purposes of cooling the inductor400. In some embodiments, a pump (not shown), or any other means of oil delivery, may force ATF into the fluid paths414to cool the inductor400before subsequently exiting the fluid paths414via one or more oil outlets420. The one or more oil outlets420may be situated in the overhanging portions of the bobbin406such that they overhang the coil winding404.FIG.5demonstrated that the ATF may be fed to the inductor400via the oil inlet416where it travels through the at least one fluid path414between the oil inlet416and the cavity412, occupied by the plug418before traveling to the at least one fluid path414between the cavity412and the coils404. The fluid path414between the cavity412and the coils404may facilitate the cooling of the inductor400by causing the ATF to flow adjacent to the coils before and/or after the ATF exits the fluid path414via the one or more outlets420which may be situated in the overhanging portions of the bobbin406.

The plug418may further define a serpentine fluid path414between the cavity412and the coils404. This serpentine fluid path414may be used to obstruct the flow of ATF. This fluid flow obstruction may be achieved by causing the fluid to travel through a serpentine fluid path414wherein different parts of the path414have different lengths/widths.

While this disclosure discusses the plug of the subject application in the context of inductor cooling, it is to be understood that such plug can also be used in association with different components of the transmission system. Indeed, one of the advantages of the plug disclosed herein may be that it can easily be modified and replaced to meet different program needs.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure.