GB2562500A

GB2562500A - Gear pump

Info

Publication number: GB2562500A
Application number: GB1707855.1A
Authority: GB
Inventors: Andrew Martin Jamie
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2017-05-16
Filing date: 2017-05-16
Publication date: 2018-11-21
Anticipated expiration: 2037-05-16
Also published as: GB201707855D0; GB2562500B

Abstract

A pump 204 for pumping oil out of a flywheel housing is disclosed. The pump comprises a ring gear 206 attached to the flywheel 202 and pump body 214. The body at least partially encloses the ring gear and has first 310 and second 312 ends and a fluid inlet 314 and outlet 318. The centrifugal force caused by the rotation of the flywheel causes air to escape from between the teeth 210 and the first end 310 limits entry of additional air into the pump body, forming a low pressure zone. The partial vacuum formed results in a flow of fluid from the bottom of the housing to the interior of the pump body and then on to the outlet. The pump allows the flywheel housing to be drained of leaked oil, even if it is lower than the main sump of an engine. Draining the housing prevents leaked oil from interfering with the rotating components. A method of pumping oil from a flywheel housing or sump is also disclosed.

Description

(71) Applicant(s):

Perkins Engines Company Limited

Frank Perkins Way, Peterborough, Cambridgeshire, PE1 5FQ, United Kingdom (51) INT CL:

F04C 2/22 (2006.01) (56) Documents Cited:

GB 2060779 A

DE 002918284 B1

F04D 5/00 (2006.01)

WO 2002/035110 A1

US 5845617 A (58) Field of Search:

INT CL F04C, F04D, F16D

Other: EPODOC, WPI & Patents Fulltext (72) Inventor(s):

Jamie Andrew Martin (74) Agent and/or Address for Service:

Caterpillar UK Legal Services Division Eastfield, PETERBOROUGH, Cambs, PE1 5FQ, United Kingdom (54) Title of the Invention: Gear pump

Abstract Title: Flywheel scavenging pump (57) A pump 204 for pumping oil out of a flywheel housing is disclosed. The pump comprises a ring gear 206 attached to the flywheel 202 and pump body 214. The body at least partially encloses the ring gear and has first 310 and second 312 ends and a fluid inlet 314 and outlet 318. The centrifugal force caused by the rotation of the flywheel causes air to escape from between the teeth 210 and the first end 310 limits entry of additional air into the pump body, forming a low pressure zone. The partial vacuum formed results in a flow of fluid from the bottom of the housing to the interior of the pump body and then on to the outlet.

The pump allows the flywheel housing to be drained of leaked oil, even if it is lower than the main sump of an engine. Draining the housing prevents leaked oil from interfering with the rotating components.

A method of pumping oil from a flywheel housing or sump is also disclosed.

704

1/8

2/8

FIG. 2

ό > ......A

V-A

FIG. 5

7/8

FIG. 7

8/8

-1GEAR PUMP

Technical Field [0001] The present disclosure relates to a gear pump. More particularly, the present disclosure relates to the gear pump for pumping oil out of a flywheel housing.

Background [0002] Generally, an engine may include a flywheel housing or a bell housing provided thereon. The flywheel housing may enclose one or more rotating components therein, such as a crankshaft, a flywheel, a starter ring gear, bearings, and so on. The rotating components may be continuously lubricated using engine oil during operation of the engine. However, due to working clearance and/or wear and tear, leaks may occur between the rotation components resulting in accumulation of the engine oil at a bottom of the flywheel housing.

[0003] Additionally, the flywheel housing may also enclose a hydraulically operated disconnect clutch therein. The clutch may utilize the engine oil as a working fluid. During operation of the engine, controlled leakage of the engine oil may occur from the clutch. This controlled leaking may result in large amount of the engine oil to be accumulated in the bottom of the flywheel housing.

[0004] In some situations, the bottom of the flywheel housing may be located lower with respect to a main oil sump of the engine. In such a situation, it may be difficult for the leaked oil to be transferred to the main oil sump. As a result, an oil level within the main oil sump may gradually decrease in turn resulting in wastage of useful engine oil and potentially starving the engine of the engine oil. This decrease in the oil level may also increase a degradation rate of the engine oil itself.

[0005] Also, the accumulated leaked oil within the flywheel housing may interfere with the rotating components, such as the flywheel, the starter ring gear, and so on resulting in increased friction, increased drag, increased wear and tear, reduced performance, and so on. This may in turn result in premature damage to the rotating components, increased malfunction events, increased maintenance „2 cost, increased machine downtime, and so on. Hence, there is a need for an improved method for controlling an amount of the leaked oil collected within the flywheel housing.

[0006] U.S. Patent Number 2,770,971 describes a driving mechanism for an engine. The mechanism includes a rotatable member having an outwardly disposed casing disposed thereon and an operating clearance between the rotatable member and the casing. The mechanism includes a ring gear associated with a periphery of the rotatable member for driving the rotatable member. An engine starter having a casing includes the mechanism thereof and provides a clearance space around the mechanism and within the starter casing. One end of the starter casing is adapted to project within an opening in the rotatable member casing and is provided with an opening at one side of the end and within the rotatable member casing through which a driving pinion of the mechanism extends into engagement with the ring gear. A passage is formed in the rotatable member casing and extends between lower extremities of the starter casing and an interior of the rotatable member casing for draining fluid from the interior of the starter casing into the rotatable member casing.

Summary of the Disclosure [0007] In an aspect of the present disclosure, a gear pump for pumping oil out of a flywheel housing is provided. The gear pump includes a ring gear having a plurality of teeth disposed circumferentially around the ring gear. The ring gear is configured for coupling with a flywheel in the flywheel housing. The gear pump also includes a pump body having a first end, a second end, a fluid inlet, and a fluid outlet. The pump body is configured to at least partially enclose the ring gear such that rotation of the ring gear through the pump body produces a flow of air from the first end to the second end. The first end of the pump body is configured to limit entry of air into the pump body to air present between the plurality of teeth of the ring gear. The fluid inlet is disposed between the first end and the second end and is configured to provide a flow path from a bottom of the flywheel housing into an interior of the pump body. The second end of the pump body is configured to provide for expulsion of air present between the plurality of

-3teeth of the ring gear from the pump body. The fluid outlet is disposed adjacent to the second end and is configured to provide a flow path out of the pump body. In use, the flow of air between the plurality of teeth of the ring gear through the pump body pumps the oil from the bottom of the flywheel housing into the interior of the pump body and out through the fluid outlet.

[0008] In another aspect of the present disclosure, a method of pumping oil from a bottom of a flywheel housing or a sump in fluid communication with the flywheel housing is provided. The method includes rotating a ring gear having a plurality of teeth disposed circumferentially around the ring gear through a pump body that partially surrounds the ring gear. The method includes limiting entry of air into the pump body to essentially only air present between the plurality of teeth of the ring gear. The method includes generating a pressure drop within the pump body using a flow of air present between the plurality of teeth of the ring gear through the pump body. The method also includes drawing the oil from the bottom of the flywheel housing or the sump through a fluid inlet into the pump body using the pressure drop. The method further includes pumping the oil out of the pump body through a fluid outlet.

[0009] Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings [0010] FIG. 1 is a perspective view of an exemplary engine, according to an embodiment of the present disclosure;

[0011] FIG. 2 is a partial cutaway view of a portion of a flywheel housing of the engine of FIG. 1, according to an embodiment of the present disclosure;

[0012] FIG. 3 is a perspective view of a pump body of a gear pump, according to an embodiment of the present disclosure;

[0013] FIG. 4 is a side view showing a portion of the pump body installed around a ring gear of the gear pump, according to an embodiment of the present disclosure;

[0014] FIG. 5 is a perspective view showing another portion of the pump body installed around the ring gear of the gear pump, according to an embodiment of the present disclosure;

-4[0015] FIG. 6 is a perspective cutaway view of the portion of the pump body of FIG. 5, according to an embodiment of the present disclosure;

[0016] FIG. 7 is a side view of the pump body of FIG. 3 connected to an oil sump, according to an embodiment of the present disclosure; and [0017] FIG. 8 is a flowchart illustrating a method of working of the gear pump, according to an embodiment of the present disclosure.

Detailed Description [0018] Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Referring to FIG. 1, an exemplary engine 102 is illustrated. The engine 102 is an internal combustion engine powered by any fuel known in the art, such as natural gas, diesel, gasoline, and/or a combination thereof. In some embodiments, the engine 102 may be associated with a machine (not shown), such as a locomotive, a marine vessel, a land vehicle, and so on. The engine 102 and/or the machine may be employed in any industry including, but not limited to, construction, agriculture, forestry, mining, transportation, waste management, aviation, material handling, and power generation.

[0019] The engine 102 includes an engine block 104. The engine block 104 includes one or more cylinders (not shown) provided therein. The cylinders may be arranged in any configuration such as inline, radial, “V”, and so on. The engine 102 also includes a cylinder head 106 mounted on the engine block 104. The cylinder head 106 houses one or more components and/or systems (not shown) of the engine 102 such as a valve train, an intake manifold, an exhaust manifold, sensors, and so on. Additionally, the engine 102 may include various other components and/or systems (not shown) such as a crankcase, a fuel system, an air system, a cooling system, a lubrication system, a turbocharger, an exhaust gas recirculation system, an exhaust aftertreatment system, other peripheries, and so on.

[0020] The engine 102 also includes a flywheel housing 108. Referring to FIG. 2, a perspective partial cutaway view of the flywheel housing 108 is illustrated. The flywheel housing 108 encloses a flywheel 202 therein. The

-5flywheel 202 may be further operably coupled to a crankshaft (not shown) of the engine 102. The flywheel housing 108 also encloses a gear pump 204 therein. The gear pump 204 is configured to pump oil out of the flywheel housing 108. More specifically, the gear pump 204 is an oil scavenging pump associated with the flywheel housing 108.

[0021] The gear pump 204 includes a ring gear 206. The ring gear 206 is coupled to the flywheel 202. In the illustrated embodiment, the ring gear 206 is disposed on a circumference 208 of the flywheel 202. In other embodiments, the ring gear 206 may be coupled to the flywheel 202 in any other configuration known in the art such as coupling adjacent to the flywheel 202. The ring gear 206 includes a plurality of teeth 210 defining a height ΉΤ” and a width “WT” thereof. The plurality of teeth 210 is disposed along a circumference 212 thereof. The ring gear 206 may be manufactured using any material known in the art, such as a metal, a polymer, and so on. Also, the ring gear 206 may be manufactured using any manufacturing method known in the art including, but not limited to, casting, hobbing, milling, and additive manufacturing.

[0022] The gear pump 204 also includes a pump body 214. The pump body 214 is removably affixed to an inner surface 216 of the flywheel housing 108. The pump body 214 is removably affixed within the flywheel housing 108 using any known fastening method, such as bolting, screw fitting, clamping, and so on. In some embodiments, the pump body 214 may be integrally formed with respect to the flywheel housing 108, such as during manufacture of the flywheel housing 108.

[0023] In an assembled position of the pump body 214 within the flywheel housing 108, the pump body 214 at least partially encloses the ring gear 206. The pump body 214 may be manufactured using any material known in the art, such as a metal, a polymer, and so on. Also, the pump body 214 may be manufactured using any manufacturing method known in the art including, but not limited to, molding, casting, fabrication, and additive manufacturing.

[0024] Referring to FIG. 3, the pump body 214 includes a configuration substantially similar to a configuration of the inner surface 216 of the flywheel housing 108 and/or a configuration of the ring gear 206. Accordingly, the pump

-6body 214 includes a curved configuration. The pump body 214 includes a base 302 defining an inner surface 304 thereof. The base 302 extends at least partially surrounding the circumference 212 of the ring gear 206. The pump body 214 includes a first wall 306 connecting and extending away therefrom. The first wall 306 extends at least partially surrounding a first side 218 (shown in FIG. 2) of the ring gear 206.

[0025] The pump body 214 includes a second wall 308 connecting and extending away therefrom. The second wall 308 extends at least partially surrounding a second side 220 (shown in FIG. 2) of the ring gear 206. In the illustrated embodiment, each of the first wall 306 and the second wall 308 is disposed perpendicularly with respect to the base 302. Accordingly, the pump body 214 includes a C-shaped cross section (not shown). In other embodiments, one or more of the first wall 306 and the second wall 308 may be disposed at any angle with respect to the base 302 based on application requirements.

[0026] The pump body 214 includes a first end 310 and a second end 312. The second end 312 is distal with respect to the first end 310. The first end 310 defines a height Ή” and a width “W” of the pump body 214. The height Ή” is approximately equal to the height ΉΤ” of the plurality of teeth 210 of the ring gear 206. The width “W” is approximately equal to the width “WT” of the plurality of teeth 210 of the ring gear 206. The second end 312 defines an overall height “HO” of the pump body 214. The height “HO” is substantially greater with respect to the height ΉΤ” of the plurality of teeth 210 of the ring gear 206.

[0027] The pump body 214 includes a fluid inlet 314. The fluid inlet 314 is disposed between the first end 310 and the second end 312 of the pump body 214. More specifically, the fluid inlet 314 is provided in the base 302 of the pump body 214 and proximate to the first end 310 with respect to the second end 312. The fluid inlet 314 is further fluidly coupled to an oil sump 702 (shown in FIG. 7) associated with the flywheel housing 108. The oil sump 702 receives excess or leaked oil from the flywheel housing 108 and will be explained in more detail later.

[0028] The fluid inlet 314 is fluidly coupled to the oil sump 702 through a tube 704 (shown in FIG. 7). In the illustrated embodiment, the pump body 214

-Ίincludes a single fluid inlet. In other embodiments, the pump body 214 may include multiple fluid inlets coupled to a single or multiple oil sumps based on application requirements. The fluid inlet 314 provides a flow path for the oil from a bottom of the flywheel housing 108 or the oil sump 702 into an interior 316 of the pump body 214.

[0029] The pump body 214 also includes a fluid outlet 318. The fluid outlet 318 is disposed adjacent to the second end 312 of the pump body 214. In the illustrated embodiment, the fluid outlet 318 is provided in the first wall 306 of the pump body 214. In other embodiments, the fluid outlet 318 may be, additionally or optionally, provided in the second wall 308 of the pump body 214. The fluid outlet 318 is further fluidly coupled to an oil sump (not shown) associated with the engine 102. The fluid outlet 318 provides a flow path for the oil received into the interior 316 of the pump body 214 out of the pump body 214.

[0030] The pump body 214 further includes a collection slot 320. The collection slot 320 is disposed adjacent to the second end 312 of the pump body 214. Also, the collection slot 320 is provided in fluid communication with the fluid outlet 318. The collection slot 320 collects the oil pumped from the first end 310 towards the second end 312 of the pump body 214. The collection slot 320 further directs the collected oil therein into the fluid outlet 318.

[0031] Referring to FIGS. 2 and 4, in an assembled position of the pump body 214 around the ring gear 206, the first end 310 of the pump body 214 limits entry of air into the pump body 214 to air present between the plurality of teeth 210 of the ring gear 206. More specifically, as the height ΉΤ” of the plurality of teeth 210 of the ring gear 206 is approximately equal to the height Ή” of the first end 310 of the pump body 214, a minimal clearance is provided between the first end 310 and the plurality of teeth 210. During rotation of the ring gear 206 along a direction 402, a centrifugal force of the rotation directs some amount of air present around and in between the plurality of teeth 210 to be directed along a direction 404, thus escaping the pump body 214. As a result, only a remaining amount air present in spaces 406 between the plurality of teeth 210 enters the pump body 214 through the first end 310, in turn limiting entry of air into the pump body 214 through the first end 310.

--8-.

[0032] Additionally, a portion of the first wall 306 adjacent to the first end 310 of the pump body 214 extends substantially surrounding the first side 218 of the ring gear 206. Similarly, a portion of the second wall 308 adjacent to the first end 310 of the pump body 214 extends substantially surrounding the second side 220 of the ring gear 206. Also, the width “W” of the pump body 214 is approximately equal to the width “WT” of the plurality of teeth 210 of the ring gear 206. Accordingly, a minimal clearance is provided between the first wall 306 and the second wall 308 of the pump body 214 at the first end 310 and the first side 218 and the second side 220 of the ring gear 206 respectively. This minimal clearance further provides to limit entry of air into the pump body 214 through the first end 310 thereof.

[0033] Accordingly, a low pressure zone 408 is created between the first end 310 of the pump body 214 and the fluid inlet 314. More specifically, the low pressure zone 408 is created in the spaces 406 between the plurality of teeth 210 of the ring gear 206. This low pressure zone 408 creates a partial vacuum in the fluid inlet 314. Due to continuous rotation of the ring gear 206, the partial vacuum results in flow of the oil from the oil sump 702 into the interior 316 of the pump body 214 and further into spaces 410 between the plurality of teeth 210 of the ring gear 206.

[0034] As the ring gear 206 further rotates through the pump body 214, the flow of the remaining amount of air trapped in the spaces 406 between the plurality of teeth 210 of the ring gear 206 drives the oil now present in the spaces 410 between the plurality of teeth 210 of the ring gear 206 further along the inner surface 304 of the pump body 214 from the first end 310 towards the second end 312 along a direction 412.

[0035] Referring to FIG. 5, in the assembled position of the pump body 214 around the ring gear 206, a gap 502 is provided between a longitudinal edge 504 of the pump body 214 and the ring gear 206. In the illustrated embodiment, the gap 502 is provided between the longitudinal edge 504 of the first wall 306 of the pump body 214 and the first side 218 of the ring gear 206. In other embodiments, a gap (not shown) may be, additionally or optionally, provided between a longitudinal edge (not shown) of the second wall 308 of the pump

--9 body 214 and the second side 220 of the ring gear 206. The gap 502 provides entry of additional air within the pump body 214 as shown by arrows 506. The additional air provides to increase acceleration and velocity of the flow of the oil along the inner surface 304 of the pump body 214 from the first end 310 towards the second end 312.

[0036] Referring to FIG. 6, arrows 602 indicate a direction of the flow of the oil from the first end 310 towards the second end 312 of the pump body 214 along the inner surface 304 thereof and between the plurality of teeth 210 of the ring gear 206 during rotation of the ring gear 206 along the direction 402. The second end 312 of the pump body 214 is disposed tangentially with respect to the ring gear 206. Accordingly, the second end 312 of the pump body 214 provides for expulsion of air present between the plurality of teeth 210 of the ring gear 206 from the pump body 214 as shown by an arrow 604.

[0037] Simultaneously, the centrifugal force of the rotation of the ring gear 206 directs the flow of the oil tangentially into the collection slot 320 along a direction 606. As a result, high velocity of the oil along the inner surface 304 of the oil is converted into high pressure around the collection slot 320. This creates a high pressure zone 608 around the collection slot 320 and between the second end 312 and the fluid outlet 318. The high pressure provides expulsion of the oil from the pump body 214 through the fluid outlet 318. The pressure differential between the low pressure zone 408 and the high pressure zone 608 provides pumping of the oil from the fluid inlet 314 towards the fluid outlet 318 based on the rotation of the ring gear 206 with respect to the pump body 214.

[0038] Referring to FIG. 7, the excess or leaked oil received in the flywheel housing 108 may flow through the fluid inlet 314 and the tube 704 into the oil sump 702 due to gravity. As an oil level in the oil sump 702 may reach a priming level “PL”, the partial vacuum in the interior 316 of the pump body 214 created during rotation of the ring gear 206 with respect to the pump body 214 may initiate the flow of the oil from the oil sump 702 upwards into the interior 316 of the pump body 214 through the tube 704 and the fluid inlet 314. It should be noted that the priming level “PL” described herein is merely exemplary and may vary based on application requirements. For example, the priming level “PL”

-10may vary based on the partial vacuum created by the rotation of the ring gear 206 with respect to the pump body 214.

[0039] This flow of the oil may further continue from the fluid inlet 314 along the inner surface 304 of the pump body 214 towards the fluid outlet 318 based on the rotation of the ring gear 206 with respect to the pump body 2f4. The pumping of the oil may continue until the oil level in the oil sump 702 may reach a base level “BL” of the tube 704. Further, as the engine 102 may continue to operate, the excess or leaked oil may be received in the flywheel housing 108 and further into the oil sump 702 through the tube 704. As the oil level may again reach the priming level “PL”, the oil may be again pumped by the ring gear 206 and the pump body 214 out of the flywheel housing 108, and the pumping cycle may continue. Accordingly, the flow of air between the plurality of teeth 210 of the ring gear 206 through the pump body 214 pumps the oil from the bottom of the flywheel housing 108 or the oil sump 702 into the interior 316 of the pump body 214 and out through the fluid outlet 318.

Industrial Applicability [0040] The present disclosure relates to a method 800 of pumping the oil from the bottom of the flywheel housing 108 or the oil sump 702 in fluid communication with the flywheel housing 108. Referring to FIG. 8, a flowchart of the method 800 is illustrated. At step 802, the ring gear 206 having the plurality of teeth 210 disposed circumferentially there around is rotated through the pump body 214 that partially surrounds the ring gear 206. The pump body 214 is removably affixed to the inner surface 216 of the flywheel housing 108.

[0041] At step 804, entry of air into the pump body 214 is limited to essentially only air present between the plurality of teeth 210 of the ring gear 206. More specifically, the entry of air is limited by limiting the clearance between the first end 310 of the pump body 214 and the ring gear 206. As such, the height Ή” of the first end 310 of the pump body 214 is approximately equal to the height “HT’ of the plurality of teeth 210 of the ring gear 206 in order to provide the minimal clearance between the first end 310 and the plurality of teeth 210 of the ring gear 206.

[0042] Additionally, the clearance is limited between the first wall 306 and the second wall 308 of the pump body 214 at the first end 310 and the first side 218 and the second side 220 of the ring gear 206 respectively. As such, the width “W” of the pump body 214 is approximately equal to the width “WT” of the plurality of teeth 210 of the ring gear 206. Accordingly, limiting the clearance provides to limit entry of air into the pump body 214 through the first end 310 thereof.

[0043] At step 806, a pressure drop is generated within the pump body 214 using the flow of air present between the plurality of teeth 210 of the ring gear 206 through the pump body 214. More specifically, as the remaining amount air present in spaces 406 between the plurality of teeth 210 enters the pump body 214 through the first end 310, the low pressure zone 408 is created in the spaces 406 between the plurality of teeth 210 of the ring gear 206.

[0044] At step 808, the oil is drawn from the bottom of the flywheel housing 108 or the oil sump 702 through the fluid inlet 314 into the pump body 214 using the pressure drop. More specifically, the low pressure zone 408 creates the partial vacuum in the fluid inlet 314 which in turn results in the flow of the oil from the oil sump 702 into the interior 316 of the pump body 214, and further into the spaces 410 between the plurality of teeth 210 of the ring gear 206.

[0045] At step 810, the oil is pumped out of the pump body 214 through the fluid outlet 318. More specifically, as the ring gear 206 rotates and the oil is pumped along the inner surface 304 of the pump body 214 from the first end 310 towards the second end 312, the additional air is introduced within the pump body 214 through the gap 502 as shown by the arrows 506. The additional air accelerates and increases the velocity of the flow of the oil towards the second end 312. As the flow of the oil approaches the second end 312, the oil is directed tangentially along the direction 606 into the collection slot 320.

[0046] This results in reduction of the velocity of the flow of the oil and increase in the pressure of the oil around the collection slot 320 and the second end 312. The high pressure zone 608 results in pumping of the oil from the collection slot 320 through the fluid outlet 318. During continued rotation of the ring gear 206 with respect to the pump body 214, the pressure differential

-12between the low pressure zone 408 and the high pressure zone 608 results in pumping of the oil from the oil sump 702, the fluid inlet 314, and the first end 310 towards the second end 312, the collection slot 320, and the fluid outlet 318. [0047] The gear pump 204 provides a simple, efficient, and cost effective pump for scavenging the oil collected in the bottom of the flywheel housing 108 and/or the oil sump 702. The gear pump 204 provides a low pressure, high volume pump as an alternative to an additional external pump (not shown) that may be required for scavenging of the oil from the bottom of the flywheel housing 108 and/or the oil sump 702. Also, the gear pump 204 is directly operated by the flywheel 202 in turn reducing dependence and parasitic load caused by the external pump. Further, regular scavenging of the oil by the gear pump 204 may reduce friction and drag on the rotating components within the flywheel housing 108 in turn improving efficiency and reducing maintenance cost.

[0048] While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of the disclosure. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

-13Global Claims

Claims

What is claimed is:

1. A gear pump (204) for pumping oil out of a flywheel housing (108), the gear pump (204) comprising:

a ring gear (206) comprising a plurality of teeth (210) disposed circumferentially around the ring gear (206), the ring gear (206) configured for coupling with a flywheel (202) in the flywheel housing (108); and a pump body (214) comprising a first end (310), a second end (312), a fluid inlet (314), and a fluid outlet (318), the pump body (214) configured to at least partially enclose the ring gear (206) such that rotation of the ring gear (206) through the pump body (214) produces a flow of air from the first end (310) to the second end (312), wherein:

the first end (310) of the pump body (214) is configured to limit entry of air into the pump body (214) to air present between the plurality of teeth (210) of the ring gear (206);

the fluid inlet (314) is disposed between the first end (310) and the second end (312) and is configured to provide a flow path from a bottom of the flywheel housing (108) into an interior (316) of the pump body (214);

the second end (312) of the pump body (214) is configured to provide for expulsion of air present between the plurality of teeth (210) of the ring gear (206) from the pump body (214); and the fluid outlet (318) is disposed adjacent to the second end (312) and is configured to provide a flow path out of the pump body (214), wherein in use the flow of air between the plurality of teeth (210) of the ring gear (206) through the pump body (214) pumps the oil from the bottom of the flywheel housing (108) into the interior (316) of the pump body (214) and out through the fluid outlet (318).

—14—

2. The gear pump (204) of claim 1, wherein the pump body (214) further includes:

a base (302) configured to extend at least partially surrounding a circumference (212) of the ring gear (206);

a first wall (306) connecting and extending away from the base (302), the first wall (306) configured to extend at least partially surrounding a first side (218) of the ring gear (206); and a second wall (308) connecting and extending away from the base (302), the second wall (308) disposed spaced apart with respect to the first wall (306), the second wall (308) configured to extend at least partially surrounding a second side (220) of the ring gear (206).

3. The gear pump (204) of claim 1 further includes a gap (502) provided between a longitudinal edge (504) of the pump body (214) and the ring gear (206), the gap (502) configured to allow entry of air within the pump body (214).

4. The gear pump (204) of claim 1, wherein a height (H) of the pump body (214) at the first end (310) is approximately equal with respect to a height (HT) of the plurality of teeth (210) of the ring gear (206).

5. The gear pump (204) of claim 1, wherein a height (HO) of the pump body (214) at the second end (312) is greater with respect to a height (H) of the plurality of teeth (210) of the ring gear (206).

6. The gear pump (204) of claim 1, wherein the second end (312) is disposed tangentially with respect to the ring gear (206).

7. The gear pump (204) of claim 1, wherein an area of the pump body (214) between the first end (310) and the fluid inlet (314) is a low pressure zone (408).

8. The gear pump (204) of claim 1, wherein an area of the pump body (214) between the fluid outlet (318) and the second end (312) is a high pressure zone (608).

9. The gear pump (204) of claim 1, wherein the pump body (214) further includes a collection slot (320) provided on the second end (312) in association with the fluid outlet (318).

10. The gear pump (204) of claim 1, wherein the fluid inlet (314) is fluidly coupled to an oil sump (702) associated with the flywheel housing (108).

11. The gear pump (204) of claim 1, wherein the fluid outlet (318) is fluidly coupled to an oil sump associated with an engine (102).

12. The gear pump (204) of claim 1, wherein the pump body (214) includes a curved configuration.

13. The gear pump (204) of claim 1, wherein the pump body (214) includes a C-shaped cross section.

14. The gear pump (204) of claim 1, wherein the pump body (214) is removably affixed to an inner surface (216) of the flywheel housing (108).

15. The gear pump (204) of claim 1 is an oil scavenging pump associated with the flywheel housing (108).

16. A method (800) of pumping oil from a bottom of a flywheel housing (108) or a sump (702) in fluid communication with the flywheel housing (108), the method (800) comprising:

rotating a ring gear (206) comprising a plurality of teeth (210) disposed circumferentially around the ring gear (206) through a pump body (214) that partially surrounds the ring gear (206);

limiting entry of air into the pump body (214) to essentially only air present between the plurality of teeth (210) of the ring gear (206);

generating a pressure drop within the pump body (214) using a flow of air present between the plurality of teeth (210) of the ring gear (206) through the pump body (214);

drawing the oil from the bottom of the flywheel housing (108) or the sump (702) through a fluid inlet (314) into the pump body (214) using the pressure drop; and pumping the oil out of the pump body (214) through a fluid outlet (318).

17. The method (800) of claim 16, wherein limiting entry of air further includes limiting a clearance between a first end (310) of the pump body (214) and the ring gear (206).

18. The method (800) of claim 16, wherein pumping the oil further includes accelerating the oil from a first end (310) towards a second end (312) of the pump body (214) by introduction of air within the pump body (214).

19. The method (800) of claim 16, wherein pumping the oil further includes increasing a pressure of the oil from a first end (310) towards a second end (312) of the pump body (214).

20. The method (800) of claim 16, wherein pumping the oil further includes directing the oil into a collection slot (320) of the pump body (214).

Intellectual

Property Office

Application No: GB 1707855.1 Examiner: Dr Nicholas Wigley