US3759639A

US3759639A - Half-moon shaped machine

Info

Publication number: US3759639A
Application number: US00201048A
Authority: US
Inventors: H Molly
Original assignee: H Molly
Current assignee: Vickers Inc
Priority date: 1971-11-22
Filing date: 1971-11-22
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18

Abstract

A crescent type gear machine comprises a spur gear in mesh with an internal gear in a housing and a stationary crescent shaped body between spur gear and the ring gear. The space between ring gear and the housing communicates with the high pressure area of the machine, a limited low pressure area being formed between crescent shaped body spur gear and ring gear. A ring having a meander shaped section to make it radially resilient encircles said ring gear. A depression area is provided on the inner surface of said resilient ring and engages part of the periphery of the gear ring to counteract the hydraulic forces thereon. Said depression area communicates with a depression area of smaller size between said resilient ring and the housing wall, the latter depression area being defined by resilient sealing means and communicates with the low pressure connection of the machine.

Description

i United States Patent 1191 Molly I I 1 Sept. 18, 1973 HALF-MOON SHAPED MACHINE [76] Inventor: Hans Molly, Dr. Eugen-Essig-Strasse 48, Malsch, Germany 22 fined; Nov. 22, 1971 211 A 1.N6.=21I1,o41; s2 U.S.Cl. 4 s/17o, 41s/71 s11 lnt.Cl... F01c 1/10,F04c 1/06 [58] FieldofSenrch ..41s/71,170'

56 References Cited UNITED sTATEs PATENTS FOREIGN PATENTS OR APPLICATIONS 1,266,134 4/1968 Germany"; .;41s/71 2ll,7ll 10/1940 Switzerland 418/170 Primary Examiner--Carlton R. Croyle Assistant Examiner-Michael Koczo, Jr. Attorney-Darbo, Robertson & Vandenburgh 57 ABSTRACT A crescent type gear machine comprises a spur gear in mesh with an internal gear in a housing and a stationary crescent shaped body between spur gear and the ring gear. The space between ring gear and the housing communicates with the high pressure area of. the machine, a limited low pressure area being formed between crescent shaped body spur gear and ring gear. A

ring having a meander shaped section to make it radially resilient encircles said ring gear. A depression area is provided onthe inner surface of said resilient ring and engages part of the periphery of the gear ring to counteract the hydraulic forces thereon. Said depression area communicates with a depression area of smaller size between said resilient ring and the housing wall, the latter depression area being defined by resilient sealing means and communicatesv with the low pressure connection of the machine.

9 Claims, 2 m' sing'ngura PAIENIEUSEM 3,759,639

sum-1 or 2 INVENTOR. ffANs MaLLY PAIENIEDSEPIBIENS 3,759,639

SHEEY 2 0F 2 INVENTOR:

HANS MOLLY HALF-MOON SHAPED MACHINE This invention relates to a hydraulic pump or motor comprising a housing within which is a spur gear in mesh with a larger ring gear, and a stationary crescent shaped body positioned between the spur gear and the ring gear. The space between the ring gear and the housing is in communication with the high-pressure range of the machine and opens into a limited range of the suction connection defined between the half-moon shaped body, the hollow gear and the spur gear, and in which a depression field engages at the periphery of the hollow gear for supporting the hollow gear otherwise running in the high-pressure space.

Machines of the type indicated in which the gear wheels are substantially operated in high-pressure and the suction space is limited to a relatively small area, have the advantage-that the hydraulic forces applied to the gear wheels act in the sense of a seal of the suction space and tend to compress the parts. In known machines the high-pressure is limited to a narrow area and the gear wheels are operated substantially in lowpressure, the high-pressure tends to force the gear wheels apart and to make the machine loose. For this reason, machines of the first-mentioned type can be operated at very high pressures. It has shown, that at such high pressures the problem-ofdeformation of the ring gear is encountered due to the influence of the high bydraulic forces. I I

It is an object of this invention to counteract such a deformation of the ring gear.

According to the invention this object is attained by positioning between the ring gear and the housing wall, a bearing body which fits around the hollow gear with limited movement. The side of the bearing body that is adjacent the hollow gear forms a cylindrical-bearing surface and has a suction area. This suction area is in communication with a suction area of smaller size on the side of the housing on the outside of the bearing body. This lattersuction area is defined by resilient V sealing means between the bearing body and the internal housing wall and communicates with the suction connection.

In this manner, a relieving force is applied to the hollow gear by a suction area in the high-pressure space which force when correctly arranged and dimensioned, counteracts the pressure forces which'tend to deform the hollow gear. The suction area on the bearing surface on the side of the hollow gear effects a drawing of the bearing body to the hollow gear, while the suction area on the side of the housing tends to draw the bearing body withthe hollow gear-towards the housing. Since the suction area onthe side of the hollow gear has a greater size than the suction area on the outside of the bearing body, it is ensured that the bearing body remains drawn to the hollow gear and cannot be withdrawn from. the bearing body by the opposing pressure of the pressure forces and of the outer suction area. The resilient sealing means permit a limited movement of the bearing body relative to the housing. Moreover, in this manner the problem is solved of applying the suction area to a bearing body attached to the hollow gear as by suction. On the other hand, a free alignment of the bearing body to the hollow gear is ensured.

The bearing body may be constituted by a radially'resilient ring surrounding the hollow gear. By axially aligned indentations provided on the ring extending alternately from one and then from the other side, a meander-shaped section is provided which is resilient in a pheripheral direction, permitting a radial expansion and contraction of the ring.

The suction area on the side .of the housing can be defined by an O-ring effecting, due to its elasticity, a seal on the one hand and on the other hand a limited movement of the bearing body.

If suction and pressure sides change in the machine for operational reasons, the ring must have such opposing suction area arrangements on both sides of the gear wheel centers, one of which communicates with one fluid pressure connection of the machine, and the other the gear wheel centers, from these forces opposed components are produced in a direction of the connection line of the gear centers. The suction areas gear absorb the forces supporting due to the elasticity of the ring gear via the teeth on the crescent, so that no wear can occur here. I

The direction of the force components to the center of the gear and an angle of rotation-position of this relieving area favorably influencing the bending'line of this gear body results in a pivoting (illustrated in the drawing) of the areas opposed relative to the center in a direction towards the tooth engagement.

The suction area'arrange'ments serve to keep the ring gear free of the supporting forces extending on the suction side through the end of the teeth towards the crescent, and moreover to so control the deformation of the same in the sealing range that a close contact of ring gear and spur gear extending across that range is obtained.

.An illustrative embodiment of this invention will hereinafter be described more fully with reference to the accompanying drawings, in which:

FIG. 1 illustrates a section through a crescent'type hydraulic pumpor motor designed in accordance with this invention.

FIG. 2 is a perspective illustration of an annular bearing body used in such a machine.

An internal ring gear 2 and a spur gear 3 are mounted in a housingl. The ring gear has a substantially greater diameter than the spur gear. The crescent shaped space between the ring gear and the spur gear is filled out by a crescent shaped body 4 stationary with respect to the housing. The spur gear 3 can be guided forlimited movement as by means of a bearing 3a having loosene'ss at the top and-bottom with respect to the shaft 3b in a direction of the connection line of the gear wheel centers as indicated by arrow M and is otherwise supported in'the housing 1. Between the ring gear 2, the spur gear 3 and the crescent shaped body 4, a suction space 5 is defined which is in communication with a suction connection 6. The other part of the housing interior is under high-pressure and in communication with a high-pressure connection 7.

The internal diameter of the housing interior is substantially greater than the external diameter of the ring gear 2 so that an annular space is formed between the housing and the ring gear. An annular bearing body ,8 is positioned in this annular space. As can best be seen from FIG. 2, the bearing body 8 has a section 9 which is resilient in a peripheral direction. To this end, axially aligned

slots

10, 11 extend inward alternately from one side and then from the other side so that a meandershaped spatial configuration is obtained. By reason of this resilient section 9, the bearing body 8 can expand and contract in a radial direction. On its inner face, the bearing body 8 has two opposed pressure area arrangements l2 and 13 respectively on the side of the hollow gear. Depending upon the use of the'machine one or the other of these areas serves as the suction area. They are identical except one is a left and the other is a right." Thus it is necessaryonly to discuss the arrangement 12. The pressure area arrangement 12 includes a area field 14 on the inner face of the hollow gear bounded by a rectangular annular groove 15. The annular groovel is in communication with a channel 16. The channel 16 opens'into a suction area 18 which is defined between the ring 8 and the housing 1 by an O- ring 17. This outer suction area onthe side of the housing 1 is of smaller size than is the suction area 1 4. It is in communication with the suction connection 6 through a channel 19. Under the influence of the resilient section 9 a gap initially exists between the hollow gear 2 and the ring 8. Depending on the degree of pressure built up in the machine, the annular bearing body 8 is compressed and the suction area 14 pulled against the ring gear 2. At the same time, the whole bearing body 8 is drawn against the housing by the suction area 18. Thereby, a suction force is applied to the ring gear 2 which counteracts the pressure forces which could otherwise cause a deformation of the ring gear 2.

While the force components which would be vertical in FIG. 1, of the forces acting on the spur gear 3 and on the ring gear 2 substantially cancel each other through the tooth engagement, the horizontal forces are substantially absorbed by the suction area 18 so that ring gear abuts the housing only with a strongly reduced force on the right-hand side in FIG. 1. The

pressure area arrangements

12 and 13 respectively are offset downwardly (i.e. towards spur gear 3) relative to ring gear diameter which is at right angles theto the connection line of the gear wheel centers (the latter would be a vertical line in FIG. l This results from the resolution of force with the spur gear 3 of limited vertical movement relative to the housing.

The application of the suction forces to the ring gear 2 is accomplished with the invention in such a manner that the free abutment of the ring gear 2 to the crescent shaped body 4 is not impaired so that therefore a tight operation of the machine is ensured. On the other hand, the pressure forces with which the ring gear 2 abuts the crescentshaped body, is decreased to a wearreducing degree by the applied suction forces.

By reason ofthe axially aligned

slots

10 and 11 on the bearing body 8, the latter is resilient against the outer wall in an assembled state. A backlash is produced between the ring gear and the bearing body 8 which floods the suction area arrangement 12 at low operating pressure. Nonetheless, the outer suction field 18 is operating as here no pressure exists. Thus, the gear wheel operates at low operating pressure with'fully effective relief by the annular groove 15 with a tolerable leakage loss until the forces occurring here in the suction area are capable to overcome the elasticity in section 9. With the hereby increased initial pressure of the pump a highly tight operation of the machine occurs initially and is maintained up to the highest operating pressures.

I claim:

1. In a gear machine comprising a housing, an internal ring gear rotatably mounted within the housing, a spur gear meshing with the ring gear, a stationary crescent-shaped body between the gears, said housing having a low pressure connection opening into a limited area defined between the body, the ring gear and the spur gear, and a high pressure connection, means defining a high pressure field in juxtaposition to the right gear and defining a first low pressure field at the pe riphery of the ring gear," the improvement comprising:

said housing forming a rigid wall spaced from the periphery of the ring gear and defining an annular space between said wall and ring gear;

said means including a radially resilient annular hearing body in said annular space and of a size to permit limited movement of the body within the space between said wall and said ring gear periphery, said first low pressure field being on the side of said body adjacent said ring gear periphery, said means defining a second low pressure field between the first low pressure field and the wall and on the side of the body adjacent said wall, said second low pressure field being of smaller area than said first low pressure field, said means including resilient sealing means between said wall and said body and surrounding said second low pressure field, said second low pressure field communicating with said low pressure connection. I

2. in a machine as set forth in claim 1, wherein the bearing body has a section with slots therethrough from inside to outside, some of said slots being part way across the body from one edge and other slots being part way across the body from the opposite edge to define a meander-shaped section on the body to provide said radial resiliency.

3. In a machine as set forth in claim 2, wherein said resilient means is an O-ring.

4. In a machine as set forth in claim 3, wherein said high pressure field is on the side of said body adjacent said ring gear periphery and is referred to herein as the first high pressure field, said means defines a second high pressure field between the first high pressure field and the wall and on the side of the body adjacent said wall, said second high pressure field being of smaller area than said first high pressure field, said means in-' cluding resilient sealing means between said wall and said body and surrounding said second high pressure field, said high pressure fields communicating with said high pressure connection, said high and low pressure fields being on opposite sides of a line connecting the centers of the gears.

5. in a machine as set forth in claim 4, including means guiding the spur gear for limited movement in the housing in the direction of said line, said fields being offset with respect to that ring gear diameter which is at right angles to said line, said offset being in the direction of the spur gear.

6. In a machine as set forth in claim 1, wherein said resilient means'is an O-ring.

7. In a machine as set forth in claim 1, wherein said high pressure field is on the side of said body adjacent said ring gear periphery and is referred to herein as the first high pressure field, said means defines a second high pressure field between the first high pressure field and the wall and on the side of the body adjacent saidt wall, said second high pressure field being of smaller area than said first high pressure field, said means ineluding resilient sealing means between said wall and said body and surrounding said second high pressure field, said high pressure field communicating with said high pressure connection; said high and low pressure fields-being on diametrically opposite sides of a line connecting the centers of the gears.

' 8. in a machine as set forth in claim 7, including means guiding the spur gear for limited movement in the body can expand in a radial direction.

' i =o= n: =0:

-. mm STATES PATENT orrrer CERTIFICATE r @rrerron men, 7 3, 759,639 Dated September 18, 1973 Inventofls) Hans Molly It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the abstract, line 2-, "internal gear" should be "internal ring gear" Col. 1, line 331 I should have a comma after "positioning" Col. 1, line 46- I should have a comma after "which force" Col. 2, line 25 "The suction areas gear absorb" should be The suction areas on the ring gear absorb" Col. 2, line 37 "end" should be "ends" Col. 3, line 18 "area field 14 should be "suction area 14 Col. 3, line 45 insert "the" before "ring gear" Col. 3, line 45 delete "the" after "angles" Col. 4, line 14 "right gear" should be "ring gear" Col. 6, line 11 insert "and contract" after "expand" Signed and sealed this 1st, day of oeeebermm,

(SEAL) e-et-Eest:

MCCOY M. GIBSON JR. or IT iARSE-ZALL DANN Arresting Officer Commissioner of Patents FORM PC4050 (10459) USCOMM-DC eoa'Ie-poo U,$. GOVERNMENT PRlNTHIG OFFICE I 9' 0-356-334,

Claims

1. In a gear machine comprising a housing, an internal ring gear rotatably mounted within the housing, a spur gear meshing with the ring gear, a stationary crescent-shaped body between the gears, said housing having a low pressure connection opening into a limited area defined between the body, the ring gear and the spur gear, and a high pressure connection, means defining a high pressure field in juxtaposition to the right gear and defining a first low pressure field at the periphery of the ring gear, the improvement comprising: said housing forming a rigid wall spaced from the periphery of the ring gear and defining an annular space between said wall and ring gear; said means including a radially resilient annular bearing body in said annular space and of a size to permit limited movement of the body within the space between said wall and said ring gear periphery, said first low pressure field being on the side of said body adjacent said ring gear periphery, said means defining a second low pressure field between the first low pressure field and the wall and on the side of the body adjacent said wall, said second low pressure field being of smaller area than said first low pressure field, said means including resilient sealing means between said wall and said body and surrounding said second low pressure field, said second low pressure field communicating with said low pressure connection.

4. In a machine as set forth in claim 3, wherein said high pressure field is on the side of said body adjacent said ring gear periphery and is referred to herein as the first high pressure field, said means defines a second high pressure field between the first high pressure field and the wall and on the side of the body adjacent said wall, said second high pressure field being of smaller area than said first high pressure field, said means including resilient sealing means between said wall and said body and surrounding said second high pressure field, said high pressure fields communicating with said high pressure connection, said high and low pressure fields being on opposite sides of a line connecting the centers of the gears.

6. In a machine as set forth in claim 1, wherein said resilient means is an O-ring.

7. In a machine as set forth in claim 1, wherein said high pressure field is on the side of said body adjacent said ring gear periphery and is referred to herein as the first high pressure field, said means defines a second high pressure field between the first high pressure field and the wall and on the side of the body adjacent said wall, said second high pressure field being of smaller area than said first high pressure field, said means including resilient sealing means between said wall and said body and surrounding said second high pressure field, said high pressure field communicating with said high pressure connection, said high and low pressure fields being on diametrically opposite sides of a line connecting the centers of the gears.

8. In a machine as set forth in claim 7, including means guiding the spur gear for limited movement in the housing in the direction of said line, said fields being offset with respect to that ring gear diameter which is at right angles to said line, said offset beIng in the direction of the spur gear.

9. In a machine as set forth in claim 8, wherein said body is in the form of a ring and includes means for providing resiliency in a peripheral direction whereby the body can expand in a radial direction.