US3653790A

US3653790A - Liquid pump or motor

Info

Publication number: US3653790A
Application number: US36804A
Authority: US
Inventors: Richard Joseph Ifield
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1970-05-13
Filing date: 1970-05-13
Publication date: 1972-04-04
Anticipated expiration: 1989-04-04

Abstract

A hydraulic pump or motor, of the type which operates by the meshing of gears, has a pair of meshed bevel gears. The housing of the pump or motor has ports on either side of the zone where the teeth are in mesh. Within the zone where the teeth are out of mesh there is an arrangement for closing off the spaces between the teeth. Fluid under pressure is admitted to the bearing surfaces of the gears so as to oppose loads applied to the gears by the operating hydraulic fluid pressure.

Description

United States Patent Ifield Apr. 4, 197 2 [54] LIQUID PUMP OR MOTOR 1,379,653 5/1921 Shoemaker.. ..418/195 inventor: Richard Joseph meld, Beecroft Australia 2,582,413 1/1952 Clark ..418/195 [73] Assignee: Joseph Lucas (Industries) Limited, Bir- FOREIGN PATENTS OR APPLICATIONS ming m, England 891,724 12/1943 France ..418/195 [22] Flled: May 1970 Primary Examiner-Carlton R. Croyle [211 App]. No.: 36,804 Assistant Examiner-John J. Vrablik AttarneyHolman & Stern [52] 0.5. Cl ..4l8/73, 418/75, 311880119945, [57] ABSTRACT 51 1111.01 ..F0lc 1/08, F031: 3/00, F04c 1/04 A hydraulic P p or motor, of the yp which Operates y the [58] Field of Search ..418/73, 75, 194, 195 meshing of gears, has a P of meshed bevel s housing of the pump or motor has ports on either side of the zone [56] References Cited where the teeth are in mesh. Within the zone where the teeth are out of mesh there is an arrangement for closing off the UNITED STATES PATENTS spaces between the teeth. Fluid under pressure is admitted to the bearing surfaces of the gears so as to oppose loads applied 297,589 4/1884 Enke ..4l8/195 to the gears by the operating hydraulic fluid pressure 351,129 10/1886 Salomo ..4l8/195 758,214 4/1904 Nielsen ..4 1 8/ 193 3 Claims, 9 Drawing Figures Q1 safe,

PATENTEDAPR 4 I972 SHEET 4 0F 5 FIGS.

INVENTOR %Ml%ap/ PATENTEBAPR 4 I872 1 3.653 790 sum 5 OF 5 INVENTOR 611 4 46/ W ATTQRLEYS This invention relates to rotary hydraulic machines and has as an object to provide such a machine in a convenient form.

According to the invention a rotary hydraulic machine, of type in which fluid displacement accompanies the rotation of meshed gear elements, includes a housing, a pair of meshed toothed bevel gear elements which are rotatable within the housing about mutually inclined intersecting axes, entry and exit ports in the housing adjacent the zone where the teeth are meshed and means for closing off the spaces between the teeth over at least part of the zone where the teeth are out of mesh.

Examples of pumps according to the invention will now be described with referenceto the accompanying drawings in which:

FIG. 1 is a section through a pump,

FIGS. 2 and 4 are views of the pump housing parts on lines 22 and-4-4 in FIG. 1,

FIGS. 3 and 5 are scrap views on the corresponding section lines in FIGS. 2 and 4,

FIG. 6 is a detail of the pump viewed on the line 22, and

FIGS. 7, 8, and 9 show, diagrammatically alternative forms of pump.

The pump shown in FIG. 1 includes a housing in two

parts

30, 31, each of which has a bearing

portion

32, 33 and a part

spherical recess

34, 35. A pair of meshed

bevel gear elements

36, 37 have

respective shaft portions

38, 39, hemispherical end portions and axial bores 40, 41. A splined portion 42 in the bore 41 engages corresponding splines on a drive shaft 43. The shaft 43 also has an axial bore 44 which communicates with the bore 41.

A generally spherical member 45 is mounted on a wedgeshaped support 46 secured to the housing part 31. The hemispherical end portions of the

gear elements

36, 37 are formed with hemispherical recesses which mate with the member 45. A sealing member 47 (FIG. 6) is also wedge-shaped and is secured to the housing part 31.

The support 46 and member 47 lie between the teeth of the

gear elements

36, 37 where these are apart. The planes of the flat faces of the member 47 meet in a line passing through the center of the spherical member 45 and also lie close to the tips of the teeth of the

gear elements

36, 37. The member 47 sealingly engage the spherical member 45. The flat faces of the support 46 are generally in the same planes as those of the member 47 but have a greater clearance with respect to the teeth of the

gear elements

36, 37.

The housing part 30 includes

ports

48, 49 for high and low pressure fluid respectively and which are aligned with corresponding

ports

50, 51 in the part 31. The

ports

48, 49 respectively communicate with an outlet 62 and inlet 63. The

high pressure ports

48, 50 communicate with the

respective bearing portions

32, 33 via

passages

64, 65. The recess 34 in the housing part 30 has a pair of

grooves

66, 67 which communicate with the low pressure port 49 and a groove 68 which communicates with the bearing portion 32. Similarly, the recess 35 in the housing part 31 has a pair of

grooves

69, 70 which communicate with the low pressure port 51 and a groove 71 which communicates with the bearing portion 33. The areas of the

recesses

34, 35 between the

grooves

66, 67, 68, 69, 70, 71 form lands which act, in use, to provide seals between adjacent grooves when the

gear elements

36, 37 are assembled in the housing. The spherical member 45 has a through passage 72 which communicates with the bores 40, 41 of the

gear elements

36, 37 and a further passage 73 opening into the passage 72 and communicating with the

low pressure ports

49, 51.

Surrounding the shaft portion 38 is a ring seal 74 which includes a p.t.f.e. tire portion 75. The ring seal 74 is retained in position by bushes 76, 77 in the bearing portion 32. The polar axis of the ring seal 74 is inclined to the axis of the shaft portion 38, the form of the seal in its own plane thus being an ellipse. The shaft portion 39 of the gear element 37 is provided with a similar seal.

In use rotation of shaft 43 in a clockwise direction, as

viewed on arrow A in FIG. 1, operates the pump in a known manner to transfer fluid from the inlet 63 to the outlet 62. The

gear elements

36, 37 are subjected to a high pressure loading in the vicinity of the

high pressure ports

48, 50. The resultant force applied to each of the

gear elements

36, 37 may be resolved into an axial load offset from the axis of the associated

element

36, 37 and a radial load whose line of action is offset from the centre of the spherical member 45. Additionally the tooth load resulting from the meshing of the

gear elements

36, 37 produces a resultant force which it is convenient to regard as located at the centre of two pitch lines in contact. This force is normal to the face of the tooth at the pitch line and may also be resolved into offset radial and axial loads. The sum of the axial components of the aforesaid forces is an ofiset axial thrust tending to urge each

gear element

36, 37 away from the spherical member 45.

High pressure fluid is admitted to the grooves 68, 71 via the

passages

64, 65 and the bearing

portions

32, 33 and creates areas of high pressure which produce on the

gear elements

36, 37 forces whose axial components are thrusts ofiset from the axis of the associated gear element and urging the gear elements towards the spherical member 45. The radial components of the forces due to pressure in grooves 68, 71 are in opposite directions to the radial components of the loads due to pressure at the

ports

48, 50 and to the radial component of the tooth load. The dimensions of the grooves 68, 71 are such that the axial thrusts imparted by the pressure therein are less than the opposing axial thrusts, whereby the

gear elements

36, 37 are urged towards the

recesses

34, 35.

High pressure fluid escaping past the lands in the

recesses

34, 35 escapes via the

grooves

66, 67, 69, 70 to the

low pressure ports

49, 51. Fluid entering the bores of the

gear elements

36, 37 similarly escapes through the

passages

72, 73 in the spherical member 45 The combination of the radial loads and the offset axial loads on gear element 36 results in a couple tending to rotate element 36 about the center of the spherical member 45 in an anticlockwise direction as seen in FIG. 1. Fluid under pressure is admitted via passage 64 to the space 91 within the bearing portion 32 in which the bush 76 lies. The force applied via the fluid pressure to one part of the shaft portion 38 is thus substantially greater than the force so applied at a diametrally opposed part of the shaft portion 38. The ring seal 74 is so orientated that the resultant force on the shaft portion 38 opposes the couple applied by the radial loads and offset axial loads on the gear element 36. The couple on the gear element 37 is similarly opposed, fluid pressure for this purpose being admitted to bearing portion 33 via passage 65.

In the pump shown in FIG. 7 a spherical member 24 has a stem 23 which extends into a bore in gear element 38. Gear element 38 extends into a chamber 78 in the housing part 30. Stem 23 serves to secure a centrifugal impeller 79 to gear element 38 within the chamber 78. In use, member 24 rotates with gear element 38 and impeller 79 acts to draw in fluid via inlet 80 and discharge it via passages (not shown) in the

housing

30, 31 to the inlet 63 (FIG. 3).

It will be understood that a centrifugal impeller may be combined with a gear element in the pump described with reference to FIGS. 1 to 6.

The pump shown in FIG. 8 has, as before, a pair of

inclined gear elements

81, 82 rotatable in a housing 83, a spherical member 84. A member 85, which corresponds to the member 47 previously described, includes a passage 86 which communicates with an inlet 87 for the pump and also, via a passage 84g in member 84, with a divided entry port 88 for the pump.

In the pump shown in FIG. 9 liquid is supplied to the interior of spherical member 89 via a passage in one of the gear elements 90. It will be understood that any of the pump arrangements of FIGS. 1 to 6, FIG. 8 and FIG. 9 could also be used as a hydraulic motor, a liquid under pressure being supplied to the high pressure port.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A rotary hydraulic machine of the type in which fluid displacement accompanies the rotation of meshed toothed gear elements, including a housing having a chamber defined by a pair of part-spherical recesses in the housing, a pair of meshed toothed bevel gear elements which are rotatable within the housing about mutually inclined intersecting axes and having part-spherical end portions upon which the teeth are formed, surfaces on the end portions lying plosely adjacent the walls of the recesses so as effectively to provide a seal therebetween, entry and exit ports in the housing adjacent the zone where the teeth are meshed, means for closing off the spaces between the teeth over at least part of the zone where the teeth are out of mesh, a groove within a part of each said recess in the housing and means for supplying a high pressure fluid to said grooves, whereby the high pressure in said grooves provides, on the associated gear elements, an offset axial thrust tending to oppose movement of the gear elements away from said means for closing off the spaces between the teeth.

2. A rotary hydraulic machine of the type in which fluid displacement accompanies the rotation of meshed toothed gear elements, including a housing having a chamber defined by a pair of recesses in the housing, a pair of meshed toothed bevel gear elements which are rotatable within the housing about mutually inclined intersecting axes and having end portions upon which the teeth are formed, surfaces on the end portions lying closely adjacent the walls of the recesses so as effectively to provide a seal therebetween, a groove in each said recess in the housing and means for supplying a high pressure fluid to said grooves, said grooves being located in said recess at positions which are substantially diametrally opposite whichever of said ports is at the higher pressure, so that high pressure admitted, in use, to the groove provides on the associated gear element a thrust whose radial and axial components, relative to the gear elements, oppose the respective components of a thrust applied, in use, to the element as a result of said fluid displacement. I

3. A rotary hydraulic machine of the type in which fluid displacement accompanies the rotation of meshed toothed gear elements, including a housing having a chamber defined by a pair of recesses in the housing, a pair of meshed toothed bevel gear elements which are rotatable within the housing about mutually inclined intersecting axes and having end portions upon which the teeth are formed, surfaces on the end portions lying closely adjacent the walls of the recesses so as effectively to provide a seal therebetween, a pair of journal bearings in the housing, in which bearings the gear elements are respectively supported, each said bearing including a sealing ring surrounding the gear element, one part of the ring being displaced axially of the gear element with respect to a diametrally opposed part of the ring, a space defined by the sealing ring and by the seal between said end portion and said recess wall, and means for supplying fluid pressure from one of said ports to the said space, the said fluid pressure exerting on the gear element within said space a force normal to the axis of the element, and the said force applying to the element a couple which opposes the couple due to forces on the end portion of the element.

Claims

1. A rotary hydraulic machine of the type in which fluid displacement accompanies the rotation of meshed toothed gear elements, including a housing having a chamber defined by a pair of part-spherical recesses in the housing, a pair of meshed toothed bevel gear elements which are rotatable within the housing about mutually inclined intersecting axes and having part-spherical end portions upon which the teeth are formed, surfaces on the end portions lying closely adjacent the walls of the recesses so as effectively to provide a seal therebetween, entry and exit ports in the housing adjacent the zone where the teeth are meshed, means for closing off the spaces between the teeth over at least part of the zone where the teeth are out of mesh, a groove within a part of each said recess in the housing and means for supplying a high pressure fluid to said grooves, whereby the high pressure in said grooves provides, on the associated gear elements, an offset axial thrust tending to oppose movement of the gear elements away from said means for closing off the spaces between the teeth.

2. A rotary hydraulic machine of the type in which fluid displacement accompanies the rotation of meshed toothed gear elements, including a housing having a chamber defined by a pair of recesses in the housing, a pair of meshed toothed bevel gear elements which are rotatable within the housing about mutually inclined intersecting axes and having end portions upon which the teeth are formed, surfaces on the end portions lying closely adjacent the walls of the recesses so as effectively to provide a seal therebetween, a groove in each said recess in the housing and means for supplying a high pressure fluid to said grooves, said grooves being located in said recess at positions which are substantially diametrally opposite whichever of said ports is at the higher pressure, so that high pressure admitted, in use, to the groove provides on the associated gear element a thrust whose radial and axial components, relative to the gear elements, oppose the respective components of a thrust applied, in use, to the element as a result of said fluid displacement.