Hydraulic fan assembly for an engine ventilation system

A fan for an engine ventilation system includes a housing defining an inlet and an outlet. A hydraulic motor is coupled to the fan housing and includes a motor housing, motor shaft, and shaft seal disposed between the motor housing and the motor shaft. An impeller assembly is disposed in the housing, as well as a stationary baffle that includes a baffle inner edge disposed axially between the impeller assembly and a second wall of the fan housing. A deflector disc is coupled to the impeller assembly and includes a deflector disc outer edge positioned axially rearward of the baffle inner edge. The deflector disc and baffle direct any hydraulic fluid leaking past the shaft seal away from the impeller assembly to a collection chamber.

TECHNICAL FIELD

The present disclosure generally relates to ventilation systems for engines, engine enclosures, and engine compartments, and more particularly to hydraulic powered fans used in such systems.

BACKGROUND

Aftertreatment systems are often utilized to reduce emissions associated with operation of engines. The State of California and the United States Environmental Protection Agency have imposed stricter emissions requirements over time, adopting increasingly stringent standards for criteria pollutants, such as NOx, unburned hydrocarbons, carbon monoxide, sulfur dioxide, ozone, lead, and particulate matter. In addition to heat produced by engines themselves, aftertreatment systems incorporated in order to meet such requirements have contributed to excessive heat in the operation of such machines. Excessive heat associated with the engine or the aftertreatment systems may be further increased due to insulating structures designed to minimize noise transmitted to the surroundings, including the passenger compartment.

Various arrangements have been proposed for cooling the engine and related components. For example, U.S. Pat. No. 4,114,714 to Fachbach, et al. discloses a forced draft ventilation system that includes a first fan that pulls air through front grill and the radiator, and a second fan that receives air from an external inlet port directed forward the vehicle and forces the air across the engine, a portion of the heated air then being directed out of the engine compartment, and a portion of the heated air then being directed across the exhaust system and out of the vehicle. Inasmuch as the second fan is driven by the engine and is depicted as a relatively small device, and the inlet to the second fan is directed forward the vehicle, it would appear that second fan is dependent, at large in part, upon the forward movement of the vehicle to force fresh air to the second fan. Accordingly, the second fan may be unable to reduce adequately the engine compartment temperatures during idling situations, or when the machine travels in a direction such that the cab or other structure blocks ambient air flow into the engine compartment. Moreover, the air that is directed over the exhaust system has already been heated by moving over the engine itself, minimizing any resultant cooling of the exhaust components.

More recently, engine ventilation systems have been used to cool the enclosure or compartment that houses the engine and the aftertreatment systems. The engine ventilation systems may include one or more ventilation fans in addition to the engine radiator or air-to-air aftercooler fan. The engine compartment ventilation fan pressurizes the engine compartment and improves air flow through the compartment. Some machines, such as wheel loaders and hydraulic excavators, use hydraulic powered ventilation fans. Such fans are driven by a hydraulic motor having a shaft seal to prevent hydraulic fluid from leaking along the motor shaft. Should the motor shaft seal fail, hydraulic fluid may become entrained in the air flow stream exiting the ventilation fan and ultimately may be sprayed throughout the engine compartment. The operating temperatures of the aftertreatment components may be sufficiently high to ignite the hydraulic fluid, thereby presenting a potential fire hazard.

SUMMARY OF THE DISCLOSURE

According to certain aspects of this disclosure, a centrifugal fan is provided for use with a source of hydraulic fluid. The fan may include a fan housing having a first side wall defining an inlet and a second side wall spaced from the first side wall, the fan housing further defining an outlet. A hydraulic motor is coupled to the second side wall of the fan housing and includes a motor housing, a hydraulic chamber disposed in the motor housing and fluidly communicating with the source of hydraulic fluid, a rotatable motor shaft extending along a shaft axis, the motor shaft having an axially rearward end hydraulically coupled to the hydraulic chamber and an axially forward end disposed in the fan housing, and a shaft seal disposed between the motor housing and the motor shaft. An impeller assembly is coupled to the axially forward end of the motor shaft, and a stationary baffle is disposed between the first and second side walls of the fan housing, the baffle including a baffle inner edge disposed axially between the impeller assembly and the second wall. A deflector disc is coupled to the impeller assembly and includes a deflector disc outer edge positioned axially rearward of the baffle inner edge.

In another aspect of the disclosure that may be combined with any of these aspects, the fan housing may define an interior chamber and the baffle may divide the interior chamber into an impeller chamber in which the impeller assembly is disposed and a collection chamber in which the deflector disc outer edge is disposed.

In another aspect of the disclosure that may be combined with any of these aspects, the second side wall of the fan housing may be configured to define a reservoir in a lower portion of the collection chamber.

In another aspect of the disclosure that may be combined with any of these aspects, the impeller assembly may comprise an impeller plate and a plurality of impeller blades coupled to the impeller plate, each impeller blade having a radial outer periphery relative to the shaft axis, and the baffle inner edge is disposed radially inwardly of the radial outer periphery of each impeller blade.

In another aspect of the disclosure that may be combined with any of these aspects, the impeller assembly may comprise a hub, and the deflector disc may be coupled to the hub.

In another aspect of the disclosure that may be combined with any of these aspects, the deflector disc may include a planar deflector disc central portion coupled to the impeller assembly and a non-planar deflector disc outer portion defining the deflector disc outer edge.

In another aspect of the disclosure that may be combined with any of these aspects, the deflector disc outer portion may extend axially rearward from the deflector disc central portion.

In another aspect of the disclosure that may be combined with any of these aspects, the baffle may include a planar baffle outer portion coupled to the fan housing and a non-planar baffle inner portion defining the baffle inner edge.

In another aspect of the disclosure that may be combined with any of these aspects, the baffle inner portion may extend axially forward from the baffle outer portion.

In another aspect of the disclosure that may be combined with any of these aspects, a centrifugal fan is provided for use with a source of hydraulic fluid. The fan may include a fan housing defining an interior chamber, the fan housing including a first side wall defining an inlet and a second side wall spaced from the first side wall, the fan housing further defining an outlet. A stationary baffle may be coupled to the fan housing and disposed between the first and second side walls to separate the interior chamber into an impeller chamber adjacent the first side wall and a collection chamber adjacent the second side wall, the baffle including a baffle inner edge. A hydraulic motor may be coupled to the second side wall of the fan housing. The hydraulic motor may include a motor housing, a hydraulic chamber disposed in the motor housing and fluidly communicating with the source of hydraulic fluid, a rotatable motor shaft extending along a shaft axis, the motor shaft having a first end hydraulically coupled to the hydraulic chamber and a second end disposed in the impeller chamber, an outer surface of the motor shaft defining a shaft flow path for hydraulic fluid extending substantially parallel to the shaft axis, and a shaft seal disposed between the motor housing and the motor shaft and in the shaft flow path. An impeller assembly may be coupled to second end of the motor shaft and define an impeller assembly leak flow path for hydraulic fluid extending substantially perpendicular to the shaft axis from the shaft flow path to a periphery of the impeller assembly. A deflector disc may be coupled to the impeller assembly and include a deflector disc outer edge oriented toward the collection chamber and a deflector disc rear surface defining a deflector flow path for hydraulic fluid extending from an intermediate portion of the impeller assembly leak flow path, thereby to divert leaking hydraulic fluid toward the collection chamber.

In another aspect of the disclosure that may be combined with any of these aspects, a centrifugal fan is provided for use with a source of hydraulic fluid that may include a hydraulic motor having a motor housing, a hydraulic chamber disposed in the motor housing and fluidly communicating with the source of hydraulic fluid, a rotatable motor shaft extending along a shaft axis, the motor shaft having an axially rearward end hydraulically coupled to the hydraulic chamber and an axially forward end disposed in the fan housing, and a shaft seal disposed between the motor housing and the motor shaft. An impeller assembly may be coupled to the axially forward end of the motor shaft. A deflector disc may be coupled to the impeller assembly and may include a deflector disc outer edge positioned axially rearward of the baffle inner edge.

In another aspect of the disclosure that may be combined with any of these aspects, the impeller assembly may comprise an impeller plate and a plurality of impeller blades coupled to the impeller plate, each impeller blade having a radial outer periphery relative to the shaft axis, and the deflector plate outer edge is disposed radially inwardly of the radial outer periphery of each impeller blade.

DETAILED DESCRIPTION

Embodiments of a ventilation fan are disclosed for use in a ventilation system provided for an engine compartment. The engine compartment may house the engine and one or more aftertreatment systems. For some machines, such as wheel loaders and hydraulic excavators, the ventilation fan is operated using hydraulic power. The ventilation fan includes a stationary baffle and a rotating deflector disc to prevent hydraulic fluid from becoming entrained in the air stream exiting the ventilation fan. More specifically, the ventilation fan includes a housing defining an interior chamber. The stationary baffle divides the interior chamber into an impeller chamber and a collection chamber. The deflector disc is configured to divert fluid from its normal leak path by directing the fluid away from the impeller chamber and toward the collection chamber. The collection chamber may include a reservoir in which diverted fluid collects. A drain conduit fluidly communicates with the reservoir to allow the fluid to be discharged from the reservoir. The drain conduit may include a clear conduit section or drain reservoir that provides a visual indication to the user that fluid is leaking from the hydraulic fan.

Turning to the illustrated embodiments,FIG. 1shows a ventilation system100for an engine compartment102of a machine, such as a wheel loader108. While the ventilation system100is illustrated in connection with a wheel loader108, the ventilation system100disclosed herein has universal applicability in various other types of machines. The term “machine” may refer to any machine that performs some type of operation associated with an industry such as mining, construction, farming, transportation, or any other industry known in the art. For example, the machine may be a wheel loader108, an excavator, a motor grader, a landfill or other type of compactor, or a wheel dozer. Moreover, one or more implements may be connected to the machine. Such implements may be utilized for a variety of tasks, including, for example, brushing, compacting, grading, lifting, loading, plowing, ripping, and include, for example, augers, blades, breakers/hammers, brushes, buckets, compactors, cutters, forked lifting devices, grader bits and end bits, grapples, blades, rippers, scarifiers, shears, snow plows, snow wings, and others.

The illustrated wheel loader108includes a body110that includes the engine compartment102. The engine compartment102houses an engine112and aftertreatment equipment114which receives exhaust from engine112(each of these items being shown generally inFIGS. 1 and 2). The wheel loader108additionally includes a hydraulic system116that may include a plurality of components such as pumps, valves, and conduits, along with a hydraulic fluid reservoir (components not shown in detail). The hydraulic system116, as well as other systems in the machine, may include its own cooling arrangement.

The engine compartment102defines an interior118that at least partially encloses the components of the engine112, and may include one or more walls that are formed by, for example, interior surfaces of the body110. In the illustrated embodiment, a soundwall120forms a portion of the engine compartment102. In an embodiment, the engine compartment102is substantially closed, although some gaps exist that allow passage of air from inside of the engine compartment102to outside of the engine compartment.

The wheel loader108may include a radiator124for cooling engine fluid, as well a radiator fan126disposed to cause movement of air across the radiator124to cool engine fluid. While the radiator fan126may be disposed to either draw or push the cooling air across the radiator124, in the illustrated embodiment, the radiator fan126is disposed to draw air through vents130in the sides132of the machine into the area surrounding the radiator124, the radiator fan126drawing the air across the radiator124and out the back wall136of the machine.

The aftertreatment equipment114may include aftertreatment systems for reducing emissions, such as NOx, unburned hydrocarbons, carbon monoxide, sulfur dioxide, ozone, lead, and particulate matter, contained in exhaust received from the engine112during operation. Such aftertreatment systems may include, for example, selective catalytic reduction (SCR), diesel oxidation catalysts (DOC), and diesel particulate filters (DPF), which are known in the art. One or more of these aftertreatment systems may be at least partially disposed within an interior138of an aftertreatment housing104. The aftertreatment housing104may be contained substantially within the engine compartment102, as shown, or it may be separate from the engine compartment102. The aftertreatment equipment114may further include one or more sensors142and electrical components144(see, e.g.,FIG. 4), which may be disposed within the aftertreatment housing104or, for example, along the exterior of the aftertreatment housing104. The aftertreatment housing104may be formed of any suitable material, and may include insulating material. In the illustrated embodiment, the aftertreatment housing104is contained within the engine compartment102, although, alternatively, the aftertreatment housing104may form a wall of the engine compartment102.

The wheel loader108further includes a ventilation system100that includes a ventilation fan150, the output of which supplies cooling air to one or more of the components contained within the engine compartment102, the aftertreatment housing104, and/or to the sensors142. In the illustrated embodiment, a centrifugal ventilation fan150is utilized, although the ventilation fan150may be of any appropriate design and utilize any appropriate power source. Although the ventilation fan150may be electronically operated, battery powered, or directly coupled to the engine112, an embodiment is hydraulically driven by a motor152(seeFIG. 3) coupled to the hydraulic system116. In this way, the output of the ventilation fan150is not directly affected by the output of the engine112, allowing the ventilation fan150to operate at a desired speed, independent of the speed of the engine112.

The ventilation fan150of the illustrated embodiment is a centrifugal fan. While the ventilation fan150may be disposed in any appropriate location, in the illustrated embodiment, the ventilation fan150is coupled to the soundwall120. A fan housing154is formed by a volute156and a portion of the soundwall120, as may be seen inFIGS. 3-5. A plurality of fasteners, such as bolts158, may secure the volute156to the soundwall120. The soundwall120and volute156may be of any appropriate material, such as, for example, an unsaturated polyester with glass mat reinforcement, or fiberglass.

Returning toFIGS. 3 and 4, air is supplied to the ventilation fan150through an inlet air conduit162that extends from the fan housing154to the exteriors of the aftertreatment housing104and the engine compartment102. In order to minimize debris entering the ventilation fan150, the ventilation system100may further include a precleaner164disposed at an inlet166to the inlet air conduit162. In this way, air enters an inlet168to the precleaner164and flows from an outlet170of the precleaner164to the inlet166to the inlet air conduit162. Air then flows through the inlet air conduit162and from an outlet172of the inlet air conduit162to an inlet174to the ventilation fan housing154.

The precleaner164may be of any custom or conventional design. The precleaner164may include, for example, an internally mounted impeller (not shown) that throws dirt and debris to the periphery of the precleaner164such that air passing through the precleaner164to the outlet170contains less dirt and/or debris than air entering the inlet168to the precleaner164. In this way, having the inlet168to the precleaner164—and ultimately, the inlet174to the ventilation fan housing154—open to the exterior of the engine compartment102, circulates cooling air that contains reduced dirt and/or debris. This effect may be enhanced by placement of the inlet168to the precleaner164at a location distal from structures and environments that would provide warmer and/or dirtier air, such as, for example, areas near machine wheels or a road.

According to the ventilation system100, cooling air from an outlet176of the ventilation fan150is provided to at least one of the components of the engine compartment102or the aftertreatment housing104, or to the sensor142. In the illustrated embodiment, a duct178directs cooling air to each of the interiors118,138of the engine compartment102and the aftertreatment housing104, as well as to the aftertreatment sensor142disposed along the exterior of the aftertreatment housing104.

As may be seen inFIGS. 3 and 4, the duct178includes an inlet180that is fluidly coupled to the outlet176of the ventilation fan150. The duct178includes passageways that direct cooling air to various outlets positioned to direct cooling air into the engine compartment102, the aftertreatment housing104, the electrical components144, and sensors142that control the operation of the aftertreatment systems. While the duct178has been described as a single duct, it may also be considered a plurality of ducts directed to various components of the machine. Those of skill will appreciate that the ducting structure could alternately include a plurality of single ducts in fluid communication with a single outlet or respective outlets of the ventilation fan150.

As shown inFIG. 3, an air hose or duct213may be provided to supply cooling air to individual engine components where individualized cooling may be desirable. For example, a duct213may be provided to the alternator214, here through the alternator cover215into the alternator housing216. An inlet217to the duct213is coupled to the ventilation fan housing154to provide fluid communication with the ventilation fan150, while the outlet218of the duct213opens to an inlet219to the alternator cover215. In this way, the ventilation fan150pushes cooling air into the alternator housing216to directly cool the alternator214.

Returning to the cooling of the aftertreatment equipment114, as the ventilation fan150pushes air into the aftertreatment housing104to cool the aftertreatment equipment114contained therein, air, now heated by the equipment114, is expelled from the aftertreatment housing104through an aftertreatment housing outlet202(FIG. 3). In order to carry the heated air away from the machine, the aftertreatment housing outlet202connects to an elongated stack204, which is disposed at a top portion of the aftertreatment housing104in an embodiment. An outlet206of the elongated stack204exhausts heated air from the aftertreatment housing104a distance from the inlet168to the precleaner164.

Inasmuch as the engine compartment102is substantially closed, the direct flow of cooling air from the duct outlet into the engine compartment102may act to pressurize the engine compartment102. Accordingly, this pressurization of the engine compartment102not only inhibits the passage of dirt or debris that may otherwise pass into the engine compartment102through any gaps in the walls defining the engine compartment102, the pressure differential between the engine compartment102and the surrounding atmosphere may also cause the expulsion of such dirt and debris that may be disposed within the engine compartment102.

In order to allow the escape of heated air from the engine compartment102, an engine compartment outlet208(FIG. 2) is provided. In the illustrated embodiment, the engine compartment outlet208is provided near the upper portion of the engine compartment102to allow the rising heated air to escape. An elongated stack210is fluidly coupled to the outlet208of the engine compartment102, allowing the heated air to rise up out of the engine compartment102and be exhausted at a distance from the inlet168to the precleaner164.

According to an embodiment, the engine compartment outlet208and the elongated stack210of the engine compartment circumferentially surrounds the elongated stack204associated with the aftertreatment housing outlet202. As may be seen inFIG. 3, in an embodiment, the outlet206of the aftertreatment housing elongated stack204extends only a portion of the height of the elongated stack210of the engine compartment102. Accordingly, the nesting of these stacks204,210acts as a venturi such that the heated air entering the elongated stack204from the aftertreatment housing104exits the outlet206at a distal end212of the stack204at a relatively high speed, creating an area of low pressure around the periphery of the distal end212. As a result, the high speed, heated air leaving the aftertreatment housing stack204pulls with it the heated air within the engine compartment stack210, carrying the heated air away from the machine.

Returning to the ventilation fan150, as noted above the fan housing154is formed by the volute156and a portion of the soundwall120. As best shown inFIG. 6, the portion of the soundwall120provides a first housing side wall250while the volute156provides a second housing side wall252spaced from the first housing side wall250. The first housing side wall250has an aperture254defining the fan inlet174. The fan150also includes the fan outlet176. The fan housing154further defines an interior chamber256for receiving fan components, as described in greater detail below.

A stationary baffle258is provided inside the fan housing154that divides the interior chamber256into an impeller chamber260and a collection chamber262. As best shown inFIGS. 5 and 6, the baffle258is disposed between the first and second side walls250,252of the fan housing154. The baffle258includes a substantially planar baffle outer portion264and a non-planar baffle inner portion266(FIGS. 7A and 7B). The baffle inner portion266defines a baffle inner edge268that extends toward the first side wall250of the fan housing154.

As best illustrated inFIG. 6, the fan motor152may be coupled to the second side wall252of the fan housing154. The motor152may be hydraulically powered, and therefore may include a hydraulic chamber270disposed in a motor housing271and fluidly communicating with a source of hydraulic fluid, such as the hydraulic system116. The motor152may further include a rotatable motor shaft272extending along a shaft axis274that defines an axially rearward direction274A and an axially forward direction274B. As used herein, the terms “forward” and “rearward” are used to define directions relative to the motor shaft272, which may or may not be the same convention used to identify directions relative to the overall machine or the direction of machine travel. The motor shaft272has a first or axially rearward end276hydraulically coupled to the hydraulic chamber270and a second or axially forward end278extending into the impeller chamber260. A shaft seal280is provided between the motor shaft272and the motor housing271to prevent hydraulic fluid from leaking along the shaft.

The fan150also includes an impeller assembly282coupled to the motor shaft272and disposed in the impeller chamber260for drawing air into the fan inlet174and creating a ventilation air stream exiting the outlet176. As best shown inFIGS. 5 and 6, the impeller assembly282includes a hub284attached directly to the motor shaft272. An impeller plate286is attached to the hub284. A plurality of impeller blades288are mounted on the impeller plate286and oriented to create a centrifugal air stream through the fan outlet176. Each impeller blade288includes an inner periphery290disposed proximally relative to the shaft axis274and an outer periphery292disposed distally relative to the shaft axis274. In the illustrated embodiment, the baffle inner edge268is disposed radially inwardly of the radial outer periphery292of each impeller blade288.

The fan150further includes a deflector disc294. Should the shaft seal280fail, thereby leaking hydraulic fluid along the motor shaft272, the deflector disc294prevents fluid from reaching the fan airstream by directing the fluid toward the collection chamber262and away from the impeller chamber260. In the exemplary embodiment best shown inFIG. 6, the deflector disc294includes a substantially planar deflector disc central portion296coupled to the impeller plate286and a non-planar deflector disc outer portion298defining a deflector disc outer edge300(FIGS. 8A and 8B). In the illustrated embodiment, the deflector disc outer portion298extends axially rearward from the deflector disc central portion296, toward the second side wall252of the fan housing154. The outer edge300of the deflector disc294is positioned axially rearward of the inner edge268of the baffle258to ensure that any leaking hydraulic fluid is directed away from the impeller chamber260and toward the collection chamber262.

A drain assembly may be provided for discharging hydraulic fluid from the collection chamber262and for providing an indication that the shaft seal280has failed. As best shown inFIG. 6, the drain assembly may include a reservoir302formed at a bottom of the collection chamber262. The reservoir302is positioned so that hydraulic fluid directed to the collection chamber262will ultimately flow under gravity to the reservoir302. The reservoir302includes an outlet304fluidly communicating with a drain conduit306. The drain conduit306may discharge to the environment or may be coupled to a discharge chamber or reservoir (not shown) for periodic pre-operation inspection or maintenance. The drain conduit306may be formed of a translucent or transparent material to permit a user to observe fluid flow, thereby providing a visual indication that the shaft seal280has failed. Additionally or alternatively, a translucent or transparent drain tank308may be provided in the drain conduit306that allows a predetermined volume of hydraulic fluid to collect, thereby providing a more readily observable indication that the shaft seal280has failed.

It will be appreciated that certain components of the ventilation fan150may form a fan sub-assembly that may be removed and replaced, if needed. For example, the fan motor152, impeller assembly282, and deflector disc294may be removed and replaced as a unitary sub-assembly in the event the shaft seal280fails.

INDUSTRIAL APPLICABILITY

The present disclosure is applicable to machines that include a hydraulically powered ventilation fan150to cool engine112and/or aftertreatment equipment114or systems. The cooling airflow may be provided to an engine compartment102and/or aftertreatment housing104and related components to assist in controlled cooling of the compartments and components. The use of a hydraulic motor152to power the fan150introduces the possibility that hydraulic fluid may leak past the shaft seal280and become entrained in the ventilation air flow created by the fan150. The baffle258and deflector disc294direct any such leaking fluid away from the impeller assembly282, thereby reducing the likelihood of hydraulic fluid entering the ventilation air flow.

More specifically, the shaft seal280of the fan150may fail, thereby permitting hydraulic fluid to escape from the hydraulic chamber270. A leak path for the hydraulic fluid begins with a shaft flow path310extending along an outer surface312of the motor shaft272. The orientation of the shaft flow path310depends on the shape of the outer surface312, which in the illustrated embodiment is substantially parallel to the shaft axis274.

As the hydraulic fluid travels axially forward along the motor shaft272, it will ultimately reach the impeller assembly282. Specifically, the hub284of the impeller assembly282may be press fit onto the motor shaft272, so that the hydraulic fluid is diverted from traveling further along the outer surface312of the motor shaft272. A rear face314of the impeller assembly282, namely rear surfaces the hub284and impeller plate286, define an impeller assembly leak flow path316that extends substantially perpendicular or radially relative to the shaft axis274from the motor shaft272to an outer edge of the impeller plate286.

A rear surface320of the deflector disc294defines a deflector flow path318for directing leaking hydraulic fluid from the impeller assembly leak flow path316to the collection chamber262. The deflector disc294has an inner periphery coupled to an intermediate portion of the impeller plate286located between the inner and outer peripheries of the impeller plate286. Accordingly, the deflector flow path318extends from the intermediate portion of the impeller plate286thereby to divert leaking fluid toward the collection chamber262. The deflector flow path318may include a first portion that is oriented substantially perpendicular to (or radially from) the shaft axis274, and a second portion that is angled axially rearward toward the collection chamber262.

In operation, the impeller assembly282and deflector disc294rotate with the motor shaft272. Hydraulic fluid leaking past the shaft seal280will first travel axially forward along the shaft flow path310until it reaches the impeller assembly282. The fluid will then be diverted to flow generally radially along the impeller assembly leak flow path316until it reaches the deflector disc294. The hydraulic fluid next travels along the deflector flow path318until it reaches the outer edge300. Centrifugal force will discharge the hydraulic fluid from the outer edge300in a substantially radial direction. The inner edge268of the baffle258is positioned to receive the fluid ejected from the deflector plate, thereby retaining the fluid in the collection chamber262. As noted above, hydraulic fluid in the collection chamber262will flow to the reservoir302under the force of gravity, where it may be discharged through the drain assembly.