US3724975A

US3724975A - Gear motor or pump

Info

Publication number: US3724975A
Application number: US00135075A
Authority: US
Inventors: K Bschorer
Original assignee: Friedrich Deckel AG
Current assignee: Friedrich Deckel AG
Priority date: 1970-04-27
Filing date: 1971-04-19
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03
Also published as: CH539781A; AT311179B; FR2086389B1; JPS5031281B1; DE2119081B2; FR2086389A1; DE2119081A1

Abstract

A multi-stage gear motor or pump utilizing a single central gear common to all stages and individual gears each cooperating with the central gear to provide the several stages. The individual gears are arranged equi-distantly from each other around and in engagement with the central gear. Portions of the housing extend between the individual gears to points close to the central gear to provide operating chambers adjacent each of the gear mesh points. Valving is arranged, preferably within the housing, to connect the operating chambers as desired, serially, parallel, by-passed or partially one and partially another. Where rotary valves are used, simple means can be provided for operating the valves simultaneously or successively from a single control.

Description

United States Patent 1 Bschorer [54] GEAR MOTOR OR PUMP [75] Inventor: Konrad Bschorer, Wolfratshausen,

Germany [73] Assignee: Friedrich Deckel Aktiengesellschaft, Munich, Germany [22] Filed: Apr. 19, 1971 [21] Appl. No.: 135,075

[30] Foreign Application Priority Data Apr. 27, 1970 Austria ..3834

[52] US. Cl. ..418/10, 418/196, 251/249 [51] Int. Cl ..F01c l/08, F03c 3/00, F04C 1/04 [58] Field of Search ..418/10, 165, 196; 74/436; 251/249 [56] 1 References Cited UNITED STATES PATENTS 798,848 9/1905 Warren ..418/10 1,983,216 12/1934 Carter et a1. ..418/196 226,023 3/1880 Booklet ..74/436 897,595 9/1908 Crouch et al.... ..418/196 3,207,111 9/1965 Giliberty ..74/436 3,523,460 8/1970 Beauvais ..251/249 748,196 12/1903 Le Rond ..418/10 [111 3,724,975 51 Apr. 3, 1973 FOREIGN PATENTS OR APPLICATIONS 465,363 5/1937 Great Britain ..418/165 990,073, 5/1951 France ..418/196 985,331 3/1965 Great Britain ..418/196 Primary Examiner-William L. Freeh Assistant Examiner-John J. Vrablik A'ttomeyWoodhams, Blanchard & Flynn [57] ABSTRACT A multi-stage gear motor or pump utilizing a single central gear common to all stages and individual gears each cooperating with the central gear to provide the several stages. The individual gears are arranged equidistantly from each other around and in engagement with the central gear. Portions of the housing extend between the individual gears to points close to the central gear to provide operating chambers adjacent each of the gear mesh points. Valving is arranged, preferably within the housing, to connect the operating chambers as desired, serially, parallel, by-passed or partially one and partially another. Where rotary valves are used, simple means can be provided for operating the valves simultaneously or successively from a single control.

6 Claims, 23 Drawing Figures PATENIEDAPRS I975 3,724,975

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sum UBUF 10 JMKKMK W PATENTEUAFRB 1915 3,724,975

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INVER'TGR PAIENIEWR 3 m5 SHEET lOUF 1O GEAR MOTOR R PUMP or driving gear is connected to the main or output shaft.

German Auslegeschrift No. 1 185 926 discloses a gear motor with more than two gears of which one gear is connected to the output shaft. The gears are arranged in an even number on a common circle in such a manner that each gear engages the two adjacent gears and all gears are thereby in direct or indirect engagement. Ports located in the housing open at the meshing points. The ports are provided interchangeably for the feeding or discharging of a pressure medium, said medium being admitted from some other point either under a high pressure or a low pressure. Thus there is provided an arrangement of several common gear motors connected to one another and each having two gears.

This gear motor is obviously provided to achieve a relatively great output but to require only a small space. However, it has a number of disadvantages. First of all, the asymmetrical load is undesireable. Commencing with the gear which is the farthest from the driven gear, the individual gears and their bearings must absorb increasing forces as one approaches the driven gear. The ports open in the directionof the meshing points so that a hydrodynamic operation is not possible and only low rotational speeds may be used. During the manufacture there exists the difficulty of adjusting the many meshing points with respect to each other. The arrangement uses a number of teeth which is equal in all gears so that especially at low rotational speed there exists deficiencies with respect to the synchronism of the gear motor. Like all known gear motors and pumps, this gear motor cannot be shifted. Known gear motors are designed for relatively low rotational speed and thus for a hydrostatic'or a mainly hydrostatic operation and are therefore not suitable for high rotational speeds.

Axial piston motors or pumps and rotary rams or pumps are known on shiftable or controllable pressuremedium-operated motors or on pumps used for conveying of fluids.

Adjustable axial piston motors, however, are expensive to manufacture, requiring joints, calottes, swash plates, an exact fitting of the pistons and a control of the inlets and outlets. Compared to the gear motors, the oscillating forces are also disadvantageous.

Rotary rams are similarly expensive tomanufacture, particularly with respect to the guiding and sealing of the vanes which in addition are exposed at their peripheral edges to an unavoidable wear by dragging or sliding on the inner wall of the housing. Both cocking moment and bending moment act on the vanes, which make theconstruction of effective radial guides very difficult.

Axial piston motors and rotary rams or pumps are much more expensive than gear motors or pumps. They are preferred primarily for the reason that they offer the advantage of shiftability and adjustability. This advantage is thus obtained only in conjunction with a heavy additional expense.

The basic purpose of the invention is to produce a pressure-medium-driven motor or a pump in which the above-discussed disadvantages are avoided, and particularly a gear motor or a gear pump which at low expense and favorable operating characteristics offers the advantage of shiftability or controlability, which furthermore can be operated easily and which at the same time permits higher rotational speeds, namely a hydrodynamic operation.

In a gear motor or a gear pump with more than two gears supported in a housing which is provided with ports for feeding and discharging of a pressure medium or a fluid to be conveyed, of which gears one gearthe driven gear if a pump or driving gear if a motor is connected to the output shaft or main shaft, the purpose of the invention is attained by providing at least two additional gears which are connected solely to the one gear and which are separated from one another by radially positioned housing sections. Such housing sections extends to the one gear and a port is provided therethrough on both sides of each of the gear meshing points. A pressure or suction chamber is also provided in said housing section and said port in the adjacent radial housing section opens thereto for feeding or discharging of a pressure medium or a fluid to be conveyed. Valves or the like are provided for the selective connection of the ports adjacent in or rather to a radial housing section with one another or in a gear motor with the pressure line and the suction line of a pressure medium supply source or in a gear pump a discharge point and one common or different supply point of a fluid which must be conveyed or rather subjected to pressure. Thus there is provided several connectedly arranged, common gear motor units but having the advantageous feature that all these gear motor units consist each of one individual and one common gear, that is, the driven or driving 'gear and for each gear motor unit only one further gear. The construction of the invention permits, by a suitable positioning of the valves and at an unchanged pressure and volume of the pressure medium, the adjustment of selected ones, or all, of these gear motor units as desired so that the gear motor at a constant product of torque and rotational speed can be shifted or adjusted in a wide zone to a selected value between low torque at high rotational speed and high torque at low rotational speed. The

desired number of stages can be achieved in a simple manner by arranging a suitable number of further gears so that the steps, if necessary, can be maintained very small. Due to the shiftability or adjustability of the gear motor a stepless adjustment provided at the pressure medium supply source is enlarged or through the latter (namely the stepless adjustments of the supply source) a stepless adjustment of the torque or the rotational speed, is made possible, which stepless adjustment exceeds the stepwise shiftability of the gear motor. Aside from the advantage of a relatively low expense, which advantage is clear for gear motors compared with other pressure-medium operated motors, the gear motor of the invention aside from the advantage of its shiftability is highly economical in that only for the first gear motor unit are two gears required and for each further gear motor unit only one further gear is needed. The gear motors of the invention can for example be used in machine tools, as for operating the main spindle on milling machines, whereby advantageously an adjustment with high torque and low rotational speed can be used for rough work, and without any loss in output an adjustment with low torque and high rotational speed can be used for fine work.

In one preferred embodiment of the invention, the driven or driving gear driven gear if a pump and driving gear if a motor is arranged centrally and on its circumference the further gears are distributed circumferentially equidistant from one another. By this arrangement, the radial forces are symmetrically distributed and asymmetrical stresses of the bearing of the driven or driving gear are avoided. This even distribution of forces offers an additional advantage in the design and manufacture of the gear motor or the gear pump of the invention.

A further feature of the invention consists in that the outer gears are in different tooth engaging positions. This is obtained by suitable selection of the central angle or the circumferential spacing of the outer gears as referred to the axis of the driven or driving gear and by selecting a suitable number of teeth and/or at equal circumferential spacings a number of teeth of the driven or driving gear or the like, said number of teeth corresponding to a prime number, through which particularly at low rotational speeds a good synchronism of the gear motor is achieved.

According to the invention, a particularly advantageous feature consists in that the valves or the like are arranged within the radial housing sections, that in the outer zone of the housing two header channels are provided which are positioned one behind the other in axial direction, each having a connecting branch or the like, that a connecting passage leads from each header channel to each valve, and that the adjusting member of the valve is constructed like a rotary piston and is provided with angularly offset valve ports. Said valve ports selectively connect the two header channels to the two ports leading to the meshing points or they connect the two ports to one another with a simultaneous blocking of the connecting passages. Thus, the gear motor or the gear pump by internally containing the valves attains a compact arrangement which can be manufactured easily, the valves can be fitted easily and two related functions can be performed simultaneously by each valve. In addition to the advantages of economy, the operation of the valving is made easier.

For use as a gear pump, a desireable feature of the invention consists in that if the valves are arranged inside the housing, a header channel is arranged for the ports on the suction side in the outer zone of the housing, from which header channel a connecting passage is lead to each valve, and that the ports on the pressure side extend separately from one another beyond the valves each to one outlet port, with connecting branches or the like. Through this construction it is possible to pressurize, by means of a driving motor with the gear pump, several supply points separately from one another at different amounts and/or pressures.

Furthermore according to the invention in the pressure or suction chambers in front or behind the meshing points there are inserted fluid-carrying wedges or the openings of the ports which openings face the meshing points are divided approximately deltoid. The kinetic energy which the pressure medium has at a great flow speed necessary for achieving high rotational speeds through this construction does not act on the meshing point, rather it is directed by the flowing pressure medium to the teeth of the central gear and the respective outer gear, which teeth are to be driven.

A further feature of the invention is that the wall sections which radially enclose the outer gears are recessed in comparison with said gears, which reduces the pressure onto the bearings of the outer gears and, particularly in case of hydrodynamic operation, reduces the friction between the flowing pressure medium and these wall sections.

A still further feature of the invention is that it is possible for the valves to be united in a single valve member with a common control member. It is further possible to use an operating member provided with one single control member, such as, in the case of valve members which are constructed like rotary pistons with control positions positioned angularly to one another, providing torque-transmitting elements, as pinions, on each of the several adjusting members and, as a common operating member, a disk or a ring arranged concentrically to the axes of the adjusting members, which disk or ring corresponding with the required control positions of the adjusting members is provided segmentally with torque transmitting elements, like toothed sections. Together with economy of space and structural simplicity, this makes it possible to shift the gear motor or the gear pump in a simple manner.

In this respect a particularly advantageous construction consists in that according to the invention there is provided on the disk or the ring as operating member for each adjusting member at least one single tooth as a torque-transmitting element, and on each adjusting member there is provided a small disk with at least one slot for the single tooth or several single teeth, and that a circular locking disk is provided coaxially on the disk or the ring and curved surfaces adjusted to the radius of the locking disk are provided on the small disks in such a manner that the small disks are rotated at a predetermined angle by means of one single tooth and the slot and are locked in their respective position by engagement of the locking disk into the curved surfaces, if necessary, with the support of one of the single teeth.

Finally it is suggested according to the invention that the housing be composed of at least three platelike members of which the two outer members contain the bearings for the shaft or axis of the central gear and the further gears and one of the header channels each, advantageously in form of an axially directed annular groove and also the connecting passages and that the central member or members have the wall sections which are positioned radially to the driven or driving gear and the further gears, the radial housing sections with the ports and if desired the fluid-carrying wedges. In this construction the parts of the housing can be manufactured in an economical manner, preferably by casting and can be accurately and easily worked by means of ordinary machines and devices.

The character of the invention is illustrated in the drawings, in which:

FIG. 1 is a central, sectional view along the line II ofa gear motor, shown in FIG. 3.

FIG. 2 is a crosssectional view along the line IIII of FIG. 3 of the gear motor, shifted at 45 compared with the illustration of FIG. 1.

FIGS. 3-5 are cross-sectional views along the line III-III of FIGS. 1 and 2 of the gear motor in three different positions.

FIG. 6 is an indicator diagram of this gear motor.

FIGS. 7a and 8a are enlarged fragments of a portion of the gear motor of FIGS. 3-5 with different positions of the valve.

FIGS. 7b and 8b illustrate unwindings of these valves in their positions according to FIGS. 7a and 8a.

FIGS. 9a to 12a schematically illustrate the gear motor in its different positions.

FIGS. 9b to 12b schematically illustrate an operating mechanism for this gear motor in the positions corresponding to FIGS. 9a to 12a.

FIGS. 90 to 12c are diagrams of the performance figures of this gear motor in the different positions.

FIG. 13 is a schematic and cross-sectional view of a gear pump taken along a plane perpendicular to the axis.

The construction according to FIGS. 1-12 permit both a use as a gear motor and use as a gear pump while the construction according to FIG. 13 is for a gear pump.

According to the drawings, a gear motor or a gear pump comprises a housing 1 or 1' (the primed numerals referring to FIG. 13) consisting of three

platelike members

11, 12 and 13 or 11, 12' or 13 assembled by means of screw connections 14, a driven or driving gear 2, a gear, and further gears 3.

The central (whether driven or driving) gear 2 is, according to FIGS. 1 and 2, rotatably fixedly connected to an output or main shaft 21 by a key 22 and is supported by means of needle bearings 23 which are secured with snap rings 24,25 and a retaining ring 26 by means of screw connections 27 in suitable openings of the

platelike members

11 and 13 or 11' and 13' in the housing 1. A seal ring 28 is arranged in the retaining ring 26.

The further (outer) gears 3 are, according to FIG. 2, supported on shafts 32 by means of needle bearings 31, which shafts are positioned in corresponding openings of the platelike members 1 1 and 13 or 11 and 13'.

The outer gears 3 engage individually the central gear 2 at the several meshing points E and are separated by radially positioned housing sections 121 which extend to a point close to the central gear 2. The central gear is thereby arranged centrally and the outer gears 3 are arranged along its circumference at equal pitch distances to one another. According to FIG. 7a the outer gears 3 are, by selecting a number of teeth of the central gear 2 which number of teeth corresponds to a prime number, in constantly changing tooth engaging positions with respect to one another.

Valves 5 are arranged in the radial housing sections 121 of the platelike member 12 of the housing 1. These valves consist of a valve bore 51 which is axially parallel to the axis of the gear motor or the gear pump and a rotary-pistonlike adjusting member 52, the two control positions of which can be obtained by a rotation of 90.

Ports

61 and 62 for feeding and discharging of a pressure medium or a fluid to be conveyed extend through the radial housing sections 121 from the valves 5 to the adjacent meshing points. Fluid-carrying wedges 122 are inserted in the pressure or suction chambers in front and behind the meshing points E. In other words, the

ports

61 and 62 are divided approximately deltoid at their openings toward the meshing points E.

In the outer zone of the housing 1, there are provided two

header channels

63 and 64, each with one connecting

passage

65 or 66, which header channels are positioned approximately in an axial direction one behind the other. The

header channels

63 and 64 are recessed in form of axial annular grooves in the plate-like members l1 and 13. One connecting

passage

67 or 68 extends from each

header channel

63,64 to each valve 5.

In the adjusting members 52 of the valves 5 there are arranged connecting passages 54 in such a manner that selectively and interchangeably the

ports

61 and 62 which are positioned adjacent one another in a radial housing section 121 by blocking the connecting

passages

67 and 68 can be connected to each other (FIG. 7a) or the port 61 can be connected to the connecting passage 67 and the port 62 to the connecting passage 68 (FIG. 8a). As is not further illustrated, in a gear motor the header channel 63 is connected through its connecting passage 65 to the pressure line and the header channel 64 is connected through its connecting passage 66 to the suction or return line of a pressure medium supply source. Of course, by reversing the feed direction, the direction of rotation of the gear motor can be reversed. For a gear pump wherein the drive takes place from the main shaft 21, a corresponding operation is obtained, the only difference being that the

header channels

63 and 64 must be connected to the discharge point and to the supply point respectively of the fluid to be conveyed.

A common header channel 63" with connecting branch 65' is arranged according to FIG. 13 in the gear pump (shown in a top view) in the outer zone of the housing 1 for the ports 61 on the suction side and the connecting passages 67 The ports 62 on the pressure side are, however, separate from one another and extendoutwardly beyond the valves 5 each with one separate outlet passage 69 with connecting branches 69a. This makes it possible to supply from a storage reservoir or another fluid source a number of different places with fluid, which number can be as high as the number of gear motor units or outlet passages 69. Depending on the position of the valves, these places can be provided with different selected pressures depending on the number of gear motor units which act onto a particular outlet passage 69.

According to FIGS. 3-5 the wall sections 123 which radially enclose the outer gears 3 and which are positioned opposite the meshing points E are, following the opening of the ports 63, arranged in stages, namely recessed opposite the gears 3 in their sections 124 so that a slightly larger flow cross section exists and pressure and friction are reduced in this zone. As is not further illustrated, common open pockets toward the pressure and suction side are provided at the meshing points E, through which pockets the pressure medium can flow from or enter into the tooth chambers which narrow downin front of the meshing point and enlarge after the meshing point.

FIGS. 3-5 and FIGS. 7a and 8a indicate in dashdotted lines the position of the connecting passages 68 which are positioned above the sectional plane and of their common header channel 64.

FIG. 7a in connection with FIG. 7b and FIG. 8a in connection with FIG. 8b illustrate the operation of a valve 5 whereby FIGS. 7b and 8b illustrate in an overlap unwindings of the valve bore 51 and of the adjusting member 52 corresponding to the valve positions of FIGS. 7a and 8a and also starting at the point A and going in clockwise direction. The angle marks 90, 180, 270 and 360 0 are thereby identified by vertical dash-dotted lines. The

ports

61 and 62 and the connecting

passages

67 and 68, closer to their openings into the valve bore 51, are illustrated in full lines, the

valve ports

53 and 54 in dashed lines. Point B of the adjusting member 52 is opposite point A in the position according to FIGS. 7a and 717, from which it reaches the position of FIGS. 8a and 8b by rotating the adjusting members 52in direction of the arrow C. In the position according to FIGS. 7a and 7b, the connecting

passages

67 and 68 and the valve ports 54 are blocked and the

ports

61 and 62 are connected by means of the valve port 53. After rotating the adjusting member in direction of the arrow C, the position according to FIGS. 8a and 8b is obtained so that the connecting port 67 is connected to the port 61 through the valve port 63 and the port 62 is connected to the connecting passage 68 through the valve port 54.

According to FIGS. 1, 2 and 9b to 12b, the valves are associated with an operating member, which is provided with one single control member in form of a control lever 71, which operating member consists of a disk 72 which is concentric to the valves 5 or the axes of the adjusting members 52. This disk is equipped with torque transmitting elements for cooperation with torque transmitting elements secured on the adjusting members 52.

According to FIGS. 1 and 2, the disk 72 is rotatably supported in a recess of a platelike member of the housing 1, which member follows on the outside the platelike member 11, and is connected rotatably fixed to the control lever 71 by means of a screw connection 73. The plate like member 15 is also provided with further recesses which are covered at the outside by a lid 151 in the zone of the valves 5.

On the disk 72, there are arranged, as a part of the operating member or as torque transmitting element, single teeth 74, namely 74a, 74b and 74c, and on each adjusting member 52, one small disk 75, namely 75a, 75b and 750 with at least one slot 76 for one of the single teeth 74. On the disk 72 there are furthermore provided coaxially a circular locking disk 77 and on the small disks 75 curved surfaces 78 which are adjusted to the radius of the locking disk 77 in such a manner that the small disks 75 are rotated at a predetermined angle by means of one single tooth 74 and a slot 76 and are locked in their respective position by engagement of the locking disk 77 into the curved surfaces 78, if necessary, with the support of one of the single teeth 74. In order to permit a rotation of the small disks 75 in this construction, recesses 79 are provided in the swivel zone of the sections surrounding the slots 76 in the locking disk 77. Finally a release 76a for the single tooth 74b in the last control position is arranged in the small disk 75c by which, if desired, the feed path can at the same time be limited. The individual control positions are identified by stationary marks I to IV and a pointer D connected to the disk 72.

This construction permits the arrangement of the single teeth 74 in such a manner that by means of the control member of the control lever 71, the valves 5 can be operated through the slots 76 and the small disks 75 in a desired and useful sequence and also according to the switch positions I to IV.

FIGS. 9a to 12a symbolically illustrate major parts of the gear motor in corresponding positions, according to FIGS. and 3, according to FIGS. 11a and 4 and also according to FIGS. 12 and 5.

In FIGS. 90 to 12c, the performance figures are illustrated diagramatically individually corresponding to the positions of FIGS. 9a or 9b to 12a or 12b. In FIG. 6 they are illustrated together in form of an indicator diagram, whereby in FIG. 6 the control positions are identified with I to IV, correspondingly the torque with Md, to Md and finally the rotational speed with n, to

In the control position I according to FIGS. 3 and 9a to 90, only one gear motor unit is provided with pressure medium so that according to FIG. 6 at a high rotational speed n, produces a small torque Md,.

In the control position II according to FIGS. 4 and 10a to 10c, two gear motor units are supplied with pressure medium, through which, starting from switch position I, a smaller rotational speed n n,/2 and a higher torque Md 2Md, are obtained as this is also illustrated in FIG. 6.

In the control position III according to FIGS. 11a to 11c, a further reduced rotational speed n, n,/3 produces a further increased torque MD, 3Md,.

Finally in the control position IV according to FIGS. 12a to 12c, all gear motor units are supplied with pressure medium so that also according to FIG. 6 a low rotational speed n n,/4 produces a high torque Md As can be recognized from the illustrated exemplary embodiment, one of the valves 5 does not require an angular adjustability so that this valve can be omitted or can be replaced by a solid insert having suitable parts.

When the gear motor is used as a gear pump, the same possibilities exist, in a reversal of the working direction, to adjust the feed pressure and volume to the respective conditions. Thus, as in the gear motor, by using a suitable number of outer gears in addition to the common driving gear, the number and fineness of the steps can be selected.

- The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A fluid-actuated rotary motor or pump, comprising:

housing means;

a central externally toothed gear supported for rotation;

a plurality of externally toothed outer gears spaced circumferentially about the periphery of said central gear and in meshing engagement with said central gear, the spacing between each of the outer gears defining generally an arcuate segment portion;

individually actuable valve means positioned in said arcuate segment portions between each of said outer gears and adapted to be controlled between first and second positions;

first and second separate annular chamber means spaced radially outwardly of said valve means one of said chamber means being adapted to contain fluid under a relatively high pressure and the other of said chamber means being adapted to contain fluid under a relatively low pressure;

first radially extending passageway means in said arcuate segment portions for permitting a fluid transfer between said first and second annular chamber means through said valve means when said valve means is in said first position;

second radially extending passageway means in said arcuate segment portions for permitting a fluid transfer between the location of each of the meshing engagements between said outer gears and said central gears through said valve means when said valve means is in said first position, each of said valve means, when individually in said second position, permitting a fluid transfer between said first annular chamber means and one of said meshing engagement locations in one of said arcuate segment portions and between said second annular chamber means and the next adjacent meshing engagement location in said one arcuate segment portion.

2. A fluid actuated rotary motor or pump according to claim 1, wherein said housing means comprises a central plate housing said central gear and said plurality of outer gears and two side plates fastened to opposite sides of said central plate and housing rotary support means for said central gear and said outer gears, said first and second annular chamber means being each located in one of said side plates radially external to said outer gears.

3. A fluid actuated rotary motor or pump according to claim 2, including manually operable means connected to each of said valve means for individually operating said valve means one at a time.

4. A fluid actuated rotary motor or pump according to claim 3, wherein said manually operable means comprises a rotatable lever and connection means to each of said valve means for individually controlling the position of each of said valve means one at a time as a function of the position of saidlever.

5. A fluid actuated rotary motor or pump according to claim 1, including wedge means in said second passageway means adjacent said locations of meshing engagement for splitting the fluid flow into and out of said positions of meshing engagement.

,6. A fluid actuated rotary motor or pump according to claim 5, wherein said wedge means causes the fluid -to be directed onto the teeth of said gears at a location spaced from said points of meshing engagement.

Claims

1. A fluid-actuated rotary motor or pump, comprising: housing means; a central externally toothed gear supported for rotation; a plurality of externally toothed outer gears spaced circumferentially about the periphery of said central gear and in meshing engagement with said central gear, the spacing between each of the outer gears defining generally an arcuate segment portion; individually actuable valve means positioned in said arcuate segment portions between each of said outer gears and adapted to be controlled between first and second positions; first and second separate annular chamber means spaced radially outwardly of said valve means one of said chamber means being adapted to contain fluid under a relatively high pressure and the other of said chamber means being adapted to contain fluid under a relatively low pressure; first radially extending passageway means in said arcuate segment portions for permitting a fluid transfer between said first and second annular chamber means through said valve means when said valve means is in said first position; second radially extending passageway means in said arcuate segment portions for permitting a fluid transfer between the location of each of the meshing engagements between said outer gears and said central gears through said valve means when said valve means is in said first position, each of said valve means, when individually in said second position, permitting a fluid transfer between said first annular chamber means and one of said meshing engagement locations in one of said arcuate segment portions and between said second annular chamber means and the next adjacent meshing engagement location in said one arcuate segment portion.

4. A fluid actuated rotary motor or pump according to claim 3, wherein said manually operable means comprises a rotatable lever and connection means to each of said valve means for individually controlling the position of each of said valve means one at a time as a function of the position of said lever.

6. A fluid actuated rotary motor or pump according to claim 5, wherein said wedge means causes the fluid to be directed onto the teeth of said gears at a location spaced from said points of meshing engagement.