US3490381A

US3490381A - Fluid displacement machine

Info

Publication number: US3490381A
Application number: US695388A
Authority: US
Inventors: Willy Minnich
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-02-22
Filing date: 1968-01-03
Publication date: 1970-01-20
Anticipated expiration: 1987-01-20
Also published as: NL6716693A; CH487332A; DK124970B; NO122744B; BE707672A; GB1221671A; SE333338B; FR1553962A

Description

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United States Patent O l 3,490,381 FLUID DISPLACEMENT MACHINE Willy Minnich, 104a Wandsbeker Chaussee, Hamburg 22, Germany Filed Jan. 3, 1968, Ser. No. 695,388 Claims priority, application Germany, Feb. 22, 1967, M 72,845; Oct. 24, 1967, M 75,985 Int. Cl. F04c 1/00, 3/00 US. Cl. 103-121 8 Claims ABSTRACT OF THE DISCLOSURE The invention provides a positive fluid displacement machine, particularly for use as an oil-hydraulic motor, oil-hydraulic pump or fluid coupling which comprises an outer rotor and an inner rotor revolving about relatively eccentric axes, and sealing devices for dividing the space between the two rotors into a plurality of working chambers. The inner rotor and the outer rotor are positively coupled together by at least one coupling means. Sealing members are provided between the inner and the outer rotor and adapted to be urged by the full pressure contained in the working chambers into sealing contact with co-operating faces on the rotors, positively to convert the fluid pressure into rotary motion of the two rotors.

BACKGROUND OF THE INVENTION This invention relates to a fluid displacement machine, particularly for use as an oil-hydraulic motor, oil-hydraulic pump or fluid coupling which comprises an outer rotor and an inner rotor revolving about eccentrically oflFset axes, said two rotors being positively coupled together, and sealing devices for dividing the space between the two rotors into a plurality of working chambers.

Conventional machines comprise an outer rotor in the form of a freely rotating capsule in which an inner rotor revolves about an eccentric shaft. The inner rotor is fitted with vanes which are radially slidable in slots in the inner rotor, the outer ends of the sliding vanes being urged against the inside of the outer rotor. Friction between the ends of the sliding vanes entrains the outer rotor when the inner rotor revolves, whereby small sliding friction between the outer rotor and the ends of the vanes arises. When the rotors revolve, the capacity of the chambers formed between the vanes increases on one side of the rotors and decreases on the other.

Furthermore, machines are known such as found in US. Patent No. 2,061,950 in which the outer ends of the vanes are hingedly mounted to the inside of the outer rotor while the other ends of the vanes are radially slidably engaged in slots in the inner rotor. Important lateral clearance in the slots prevents locking of the vanes when they are moved as a result of the relative rotation between the inner and the outer rotor. Hereby, the vanes, intended to form separate sealed chambers between them, are furthermore intended to have the same effect as the actuating tooth of a gear. This efiect is, however, only insuificiently obtained insofar as the teeth are not mounted rigidly.

In other known machines such as found in US. Patents 3,306,226; 2,866,417 and 2,011,338, the inneif and the outer rotor are each provided with teeth engaging each Patented Jan. 20, 1970 the outer rotor and those of the inner rotor permanently get into sealing contact. In some embodiments additional sealing means are provided on the tooth crests for improving the sealing contact. When the rotors revolve, the size 'of the chambers formed by the teeth is increased on one side and again decreased on the other side. The chambers are connected with channels serving as inlets or outlets.

In other known machines such as are found in U.S. Patents 725,615 and 914,627, the inner rotor comprises a rotary piston the two ends of which operate as teeth. The outer rotor is provided with three recesses in its inside, which recesses form chambers comprising inlet and outlet channels. Inner and outer rotor roll off each other when revolving, the inner rotor also rotating at a higher speed than the outer rotor. Hereby, the ends of the rotary piston engage the recesses of the outer rotor one after the other thus permanently modifying the capacity of the chambers with the rotary piston permanently bearing against the outer rotor in direct sealing contact or indirectly by the interposing of special sealing means.

Whereas the volumetric efiiciency of these known machines may be satisfactory at high speed, it is unacceptably small at low speed. This is based on the fact that the generation of high torques at low speed requires large chambers in the machines, which chambers, however, 'cannot be sufiiciently sealed in the known types of construction. This drawback is particularly irksome because there is an increased demand in engineering for slowly revolving fluid motors which are reliable and eflicient and at the same time of simple construction and generate high torques.

SUMMARY OF THE INVENTION In the machine according to the invention, substantially completely tight seals of the Working chambers can be created by positively coupling the inner rotor to the outer rotor by a coupling means and by providing sliding blocks as sealing means slidable on the flat peripheral faces of the inner or the outer rotor, the outside with respect to the inside of which has the form of a polygonal prism and adapted to be urged into sealing contact with fixed fins attached to the inner or outer rotor, respectively, whereby the inner and outer rotor revolve at the same average speed, the fluid pressure exerted on the sliding blocks being positively converted into rotary motion of the two rotors. Positive coupling means may consist of a fixed projection from the inner rotor radially slidably and relatively deflectably received between two fixed guides projecting from the inside of the outer rotor, or inversely of a projection from the outer rotor received between the guides projecting from the inner rotor. Such coupling means necessarily cause the inner and outer rotor to revolve at the same average speed.

The means provided for dividing and sealing the dif ferent Working chambers are sliding blocks extending along the entire axial length of the space between the inner and outer rotor and adapted with one of their edges to maintain contact with a cooperating sealing face in the outer rotor, whereas the other edge maintains sealing contact with a cooperating sealing face on the inner rotor. When the pressure of the hydraulic fluid acts on the sliding blocks, the positive coupling between the outer rotor and the inner rotor established by the coupling means results in thrusts being applied in the area of bearing of the sliding blocks against the inner and outer rotor, said thrusts acting at the same time as sealing forces so that high torques are generated efi'iciently even at low speed 3 BRIEF DESCRIPTION OF THE DRAWINGS Several preferred embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 is a cross section of an oil hydraulic motor in which the sealing elements are sliding blocks;

FIG. 2 is a cross section of an oil hydraulic motor comprising one sliding block in each working chamber;

FIG. 3 is an axial section of the motor according to FIG. 2;

FIG. 4 is an axial section of a motor comprising external coupling means betwen the outer and inner rotor;

FIG. 5 is an axial section of the motor made in accordance with this invention;

FIG. 6 is another embodiment of an oil hydraulic motor with external fluid control means;

FIG. 7 is a cross section of the control means on the line IXIX of FIG. 6;

FIG. 8 is a cross section on the line XX of FIG. 9, showing an embodiment of a positive fluid displacement machine which is intended to function as a fluid coupling;

FIG 9 is an axial section on the line XI-XI of FIG. 8, showing the fluid coupling according to FIG. 8, and

FIG. 10 is an axial section of a machine with an inner rotor in the form of a shaft with external control means.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the motor illustrated in FIG. 5 an outer rotor 2 revolves in the direction of the arrow 3 about an axis 4, whereas an inner rotor 5 revolves about a second axis 6 parallel to the axis 4 but offset therefrom by a distance e. The inner rotor 5 and the outer rotor 2 are both rotatably mounted on a common pintle 7 of which one end, as shown in FIG. 5, is tightly fitted into a support member 38. The central portion of the fixed pintle 7 forms an eccentric bearing 23 which rotatably carries the inner rotor 5.

The outer rotor 2 consists of a drum which may be composed of a number of parts and which is rotatably mounted on the fixed pintle 7. The inner rotor 5 has the form of a sleeve which is likewise mounted on the pintle 7 and which axially extends the full length of the interior of the drum, its axial end faces making sliding contact with the inside axial end walls of the drum. As already mentioned, the center section of the pintle 7 forms an cecentric of which the longitudinal axis is ofiset from the principal pintle axis by a distance 2. This will be clearly understood from FIG. 5.

The inner and

outer rotors

5 and 2 are positively coupled by coupling means indicated generally by the reference numeral 8. These coupling means 8 consist of a rigid radial extension 9 on the inner rotor 5 received between two guides 10 projecting inwardly from the inside peripheral surface of the outer rotor 2 in such a manner that said extension 9 of the inner rotor 5 is radially slidable between the two guides 10 as well as laterally deflectable within limits in relation thereto.

Equidistantly distributed around the inside circumferential surface of the outer rotor 2 are four fixed radially inwardly projecting fins 12, each extending axially across the full length of the internal cavity enclosed by the outer rotor 2 and having axial end faces fitting tightly against the axial internal end walls of the outer rotor 2. The flanks of these fins 12 slidably co-operate with the outer longitudinal edges of flaps 13 which have inner longitudinal edges forming hinges 14 hingeably attaching the flaps 13 to the inner rotor 5. These flaps 13 which extend along the entire axial length of the inner rotor 5 are urged by springs (not shown) to maintain contact with the -cooperating flank of the fixed fins 12.

The fixed pintle 7 contains two

control grooves

15 and 16 which are supplied with oil through a duct 18 inside the pintle 7 and discharge the oil through a second duct 17 in the p tle 7, o convers y, accor g o the h of rotation of the motor. The two

grooves

15 and 16 are of like length and extend around nearly half the circumference of the pintle 7, being separated only by two webs 19 and 20. The

grooves

15 and 16 communicate through four

radial ports

21 and 22 in the inner rotor 5 with four chambers =I, II, III, and IV. The motor delivers torque via the outer rotor 2 as its output member and this may have the form of, for instance, a cable drum. In the position of the motor, the oil supplied by a pressure pump is forced through the duct 18 in the pintle 7 into the groove 16 whereupon it enters the two chambers II and III through the radial ports 22 in the inner rotor 5. The pressure of the oil in the two chambers II and III augments tfihe pressure urging the flaps 13 against the co-operating Since the outer and

inner rotors

2 and 5 are positively coupled by engagement of the rigid radial extension 9 between the two guides 10, the dilference in the radial areas of the end walls of the pressurized chambers II and III formed by the flaps 13 and the fins generates a differential thrust in the form of a torque which through the respective arms acts on the inner as well as the

outer rotors

5 and 2 about their respective axes. The thrust acting on the flaps 13 is transmitted to the inner rotor 5 through the flap hinges 14 and to the outer rotor 2 through the lines of contact between the outer-flap edges and the fixed fins 12 of the outer rotor 2. These lines of contact 25 and the hinges 14 form the sealing joints at the ends of the chambers II and III, and it will be understood that the sealing thrust is proportional to the oil pressure inside the chambers.

Moreover, the oil pressure in the chambers II and III urges the. inner rotor 5 into sealing contact with the side of the pintle 7 from which the pressure oil enters the chambers II and III through the control groove 16. If the direction of admission and discharge through the ducts in, the pintle 7 is reversed for the purpose of reversing the hand of rotation of the motor, then the inner rotor 5 will be, urged by the pressure inside the chambers I and IV into sealing contact with the opposite side of the pintle which is provided with the control groove 15 through which the pressure oil will then be admitted.

Owing to the eccentric disposition of the inner rotor 5 in relation to the outer rotor 2 and the consequent difference in the radial surface areas at the peripheral ends of the two chambers II and III, the thrust acting on these surface areas including the flaps 13 generates a resultant torque in the direction indicated by the arrow 3 and, because of the positive coupling between the two rotors, the reaction to this torque is a couple acting on the pintle 7 'with e as the base.

When the motor rotates it will be understood that oil is forced into and discharged from the chambers I to IV of the motor in virtue of the

ports

21 and 22 in the inner rotor 5 being placed into communication alternately with the

control grooves

15 and 16 in the pintle 7 to admit or discharge oil according to the hand of rotation. The average speed of rotation of both rotors is the same.

It will be readily understood that a kinematic inversion of the described arrangement will result if, contrary to the above description, the outer rotor 2 is kept stationary or fixed and the pintle 7 is allowed to rotate, in which case the latter will be the motor output shaft. This observation also applies to the further embodiments which will be hereinafter described.

The means employed for sealing the chambers I to IV of the motor may alternatively have the form of sliding blocks. FIG. 1 shows in cross section such a motor which comprises six chambers.

As in 'the embodiment described with reference to FIG. 5, an inner rotor 5 and an outer rotor 2 are rotatably mounted on a fixed pintle 7 The output member of the motor is again the outer rotor 2 which has the general shape gt a drum. Six inwardly projecting has 12 are equidistantly afiixed to the internal peripheral surface of the outer rotor 2 In the same way as in the embodiment according to FIG. 5 these fins 12 extend axially along the full length of the interior of the outer rotor 2 their axial end faces tightly abutting the axial end walls of the outer rotor 2 The outer rotor 2 rotates about the axis marked 4. The inner rotor 5 has the form of a hexagonal prism with a central bore, likewise rotatably mounted on the fixed pintle 7 and revolving about an axis 6 parallel to the axis 4 but olfset therefrom by a distance e. The hexagonal prism extends along the full length of the interior of the outer rotor 2 and with minimum clearance abuts the inside axial end walls of the outer rotor 2 Slidably mounted on each of the faces A of the hexagonal prism between the six fixed fins 12 projecting from the inside peripheral surface of the outer rotor 2 is a pair of sliding

blocks

30, 30 each pair extending the full length of the prism in such a manner that the axial end faces of the blocks slidably abut the axial end walls of the outer rotor 2 with minimum clearance. Each pair of sliding

blocks

30, 30 is contained between two neighboring fins 12 of the outer rotor 2 and is provided with internal bores 31 for the reception of a spring 34 which urges the

blocks

30, 30 of each pair apart into contact with two co-operating fins 12 of the outer rotor 2 Moreover, each of the

blocks

30 and 30 is provided with a further bore 32 for the reception of one end of a spring 33 of which the other end bears against the inside peripheral surface of the outer rotor 2 and thus urges the block against the corresponding face A of the hexagonal prism. Positive coupling between the outer and

inner rotors

2 and 5 is provided by coupling means 8 located between two fins 12 and two sliding blocks 36 and consisting of a rigid radial extension 9 fitted to the inner rotor 5 and slidably engaged between two guides 10 affixed to the inside peripheral surface of the outer rotor 2 The two sliding blocks 36 on either side of the coupling means 8 are recessed where the coupling means 8 are situated. The springs associated with these two sliding blocks 36 are not shown in FIG. 1.

For the admission and discharge of the hydraulic oil the arrangements are analogous to those described with reference to FIG. 5. Corresponding parts are identified by the same reference numerals. When the motor rotates in the direction of the arrow 3 in the embodiment according to FIG. 1, the hydraulic oil flows through the duct 18 into the control groove 16 and thence through two radial ports 22 in the inner rotor 5 into the working chambers II and III on the left in FIG. 1.

Owing to the positive coupling between the inner rotor 5 and the outer rotor 2 the hydraulic oil can urge the sliding

blocks

30, 30 and 36 into tight sealing contact with the fixed projecting fins 12 of the outer rotor 2 as well as against the faces A of the inner rotor 5 so that in practice the two pressurized chambers II and III are completely sealed. As already previously described the resultant of the differential thrusts applied to the peripheral ends of the working chambers and the associated arms about the two rotor axes generate the torque of the motor.

As the motor rotates the sliding

blocks

30, 30 and 36 slide to and fro on the hexagon faces A of the inner rotor 5 and on the inner edges of the fixed fins 12 Another embodiment of the motor proposed by the invention is illustrated in FIGS. 2 and 3. In this embodiment the outer rotor 2 is provided with five fixed fins 12 equidistantly disposed around the inside periphery of said rotor. The inner rotor 5 has the form of a pentagonal prism with a central bearing bore. The inner and

outer rotors

5 and 2 are rotatably relatively eccentrically mounted on a fixed pintle 7 The five

radial ports

21 and 22 in the inner rotor 5 through which the working chambers I to V communicate with the

control grooves

15 and 16 for the admission and return of the pressure oil through

axial ducts

17 and 18 are so disposed that their orifices are situated at the corners of the pentagonal prism 5 The flanks B of the five fixed fins 12 which define the peripheral ends of each chamber I to V are parallel. Four sliding blocks 30 slidably rest on four of the faces A of the prism 5 each between two fins 12 The width of the sliding blocks 30 is so chosen that the convex flanks 39 of the blocks 30 are contained with slight clearance between two fixed fins 12 of the outer rotor 2.

That side of each sliding block 30 which faces the inside peripheral surface of the outer rotor 2 is formed with a recess 40 for the reception of one end of a spring 33 of which the other end bears against the inside of the outer rotor 2 The spring 33 urges the block 30 against the associated face A of the pentagonal prism 5 The positive coupling between the outer and

inner rotor

2 and 5 is established by coupling means 8 which have the same shape as a sliding block 30 but which is rigidly affixed to a face of the pentagonal prism 5 and contained with slight clearance between two co-operating fins 12 of the outer rotor 2 In other words, in this arrangement the coupling means 8 simultaneously also function as a sealing member for chamber IV.

When the motor is operated, hydraulic oil admitted under pressure through the duct 18 enters the two chambers II and III through the control groove 16 and forces the sliding blocks 30 and the coupling means 8 into sealing contact with the flanks of the fins 12 Contact between the sliding blocks 30 and the faces A of the inner rotor 5 may of course also be ensured by positive constraint instead of by springs 33 For instance pins not shown in the drawing could be fitted to the faces A of the pentagonal prism and arranged to project into recesses in the undersides of the co-operating sliding blocks 30 Inside the recesses the pins could be provided with heads adapted to slide in lateral ways in the blocks 330 thereby stopping the blocks 30 from lifting without preventing them from being slidably displaced sideways on the faces A.

The means for establishing a positive coupling connection between the inner and outer rotor may also be located on the outside of the outer rotor. In such an arrangement which is illustrated in FIG. 4 the inner rotor may have the form of a rotatable shaft 205 which projects from each axial end of the outer rotor 202, and which is journalled in

outside bearings

206 and 207. The outer rotor 202 is rotatable inside an external fixed circumferential bearing member and the axes of rotation of the outer rotor 202 and of the inner rotor 205 are relatively offset by the distance marked 2 in FIG. 4. The coupling means has the form of an arm 208 which is affixed to the rotatable shaft 205, and which carries a pin 209 slidably engaging in a radial slot 210 in the outside face of the outer rotor 202. In this arrangement the output member of the motor is therefore the shaft 205 of the lnner rotor. This advantage remains if the outside cou ling arm 208 is replaced by a coupling member inside the drum-shaped outer rotor 202.

The ports, or generally speaking the means for controlling the admission and return of the pressure medium, may also be located outside the outer rotor 302. This poszibilidty is illustrated in the embodiment shown in FIGS.

The ends of a fixed pintle 307 in this embodiment are rigidly held in support means. The outer rotor 302 and the inner rotor 305 are again mounted to rotate about axes 304 and 306 that are relatively offset by a distance 2. Moreover, the inner rotor 305 and the outer rotor 302 are positively coupled together, the interior of the outer rotor 302 being divided into six relatively sealed working chambers. I

The admission and return of the working medium is controlled by two

grooves

315 and 316 in the pintle 307 which communicate with

ducts

317 and 318 and which are surrounded by a sleeve 341 rotatably mounted on the pintle 307 and provided with six radial ducts 342 in the plane of the

grooves

315 and 316.

The bores in the sleeve 341 permanently communicate through six pipes 340 with the six working chambers in the outer rotor 302, the sleeve 341 participating in the rotation of the outer rotor 302. The pipes 340 therefore connect the six radial bores 342 in the sleeve 341 via six bores 343 in the Outer rotor 302 to the six working chambers of the motor. The hydraulic oil is admitted and exhausted from these chambers through the

ducts

317 and 318, the

grooves

315 and 316 and the six pipes 340.

Compared With the previously described embodiments the provision of the

means

315, 316, 340, 341 and 342 for controlling the admission and return of the oil outside the outer rotor 302 in the manner illustrated in FIGS. 6 and 7 has the advantage that the elasticity of the pipes 340 can be utilized in conjunction with the sleeve 341 to compensate deflection of the pintle 307 when this is under load.

FIGS. 8 and 9 illustrate yet another embodiment of the invention in which the positive fluid displacement machine is contrived to function as an oil hydraulic coupling. In this arrangement one end of the input shaft 407 of the coupling runs in a bearing member 451, whereas the other end forms a journal which is freely rotatable in one end of an outer rotor 402. The outer rotor 402 is itself formed with a journal 402 which runs in a second bearing member 450. The other end of the outer rotor 402 is freely rotatably mounted on the input shaft 407. The inside peripheral wall of the drum-shaped outer rotor 402 has a hexagonal cross section. The inner rotor 405 is rotatably mounted on an eccentric portion 423 of the shaft 407 and has the form of a sleeve fitted with three fixed fins 412. The coupling means indicated generally by the reference numeral 408 which establish the required positive coupling connection between the inner and the outer rotors comprise an inward projection 410 in the outer rotor slidably and angularly movably engaging a radial recess 409 in the end of a radial fixed fin 412 projecting outwards from the inner rotor.

A sliding block 430 is arranged to slide on each of the internal hexagon faces of the outer rotor, each block being urged into contact with the flank of one of the fins 412 on the inner rotor 405 by a spring 434 carried by blind holes 431 in the block and the fin. The common axis 404 of the input and

output shafts

407 and 402 is offset from the axis of rotation 406 of the inner rotor 405 by the distance e. In order to provide for this relative eccentricity of the axis of rotation of the sleeve-shaped inner rotor 405 the latter is mounted on an eccentric portion of the input shaft 407.

The grooves 415 and 416 in the input shaft 407 through which the hydraulic oil is admitted and exhausted are separated by two

Webs

419 and 420 and contained in axially offset planes in order to improve the seal between them. These grooves 415 and 416 communicate through radial ports 421 and 422 in the inner rotor 405 with the interior of the three chambers defined by the fins 412 and the sliding blocks 430. Moreover, the control grooves 415 and 416 communicate through ducts 417 and 418 in the shaft 407 and two internal

peripheral grooves

452 and 453 in the bearing member 451 with

pipes

454 and 455 controlled by

valves

456 and 457 connected to an oil reservoir not shown.

The sliding blocks 430 are each provided with a guide slot containing a headed pin 458 fitted into the outer rotor 402 and adapted on the one hand to retain the sliding face of the block in contact with the inside face of the outer rotor 402 whilst on the other hand permitting the block to perform a to-and-fro sliding movement.

The fluid coupling illustrated in FIGS. 10 and 11 functions as follows:

When the

valves

456 and 457 are fully open and the shaft 407 revolves whilst the outer rotor 402 which represents one half of the coupling is kept stationary, hydraulic oil is circulated at low pressure from the oil reservoir, not shown in FIGS. 8 and 9, through the chambers and back again into the reservoir. A slight torque in driving direction is transmitted from shaft 407 to the outer rotor 402 and its output shaft. However, when the cross section of flow of that

valve

456 or 457 in the

pipes

454 and 455 respectively which, according to the hand of rotation, is in the return path of the oil, is throttled, the pumping pressure in the oil hydraulic coupling will rise with a consequent rise in the input torque through shaft 407 and the torque delivered by the output shaft 402 the transmitted torque corresponding to the energy loss due to slip between the input shaft 407 and the outer rotor 402. When the outer rotor 402 begins to rotate and the percentage slip between the input shaft 407 and the outer rotor 402 is reduced, the rate of circulation of the hydraulic oil likewise fall-s. It will thus be understood that the speed of rotation of the outer rotor 402 can be infinitely controlled by means of the

throttle valve

456 or 457.

When the input speed approaches the output speed the

valve

456 or 457 is closed sulficiently for the pump output to correspond to the leakage loss. Under these conditions the two valves of the coupling rotate with substantially no slip because of the high volumetric efficiency of the coupling.

To serve as overload safety devices pressure limiting valves may be incorporated in the admission and return

pipes

454 and 455. Moreover, an oil reservoir could be dispensed with and the

valves

456 and 457 built into the rotating input shaft 407, in which case the hydraulic oil would be circulated without leaving the rotating coupling.

The valves which in such an arrangement rotate together with the shaft 407 could then be automatically controlled by means of devices known in the art.

In the embodiment according to FIG. 10 an inner rotor 505 is rotatable in a bearing member 550 about an axis 506. The outer rotor 502 is rotatably mounted in the same bearing member 550 and surrounds the inner rotor 505 in spaced relationship thereto, the intervening space comprising the working chambers. The outer rotor 502 revolves about an axis 504 offset by a distance e from the axis 506. The outer rotor 502 is therefore eccentric in relation to the inner rotor 505.

The inner rotor 505 is provided with

ducts

521 and 522 corresponding in number to the number of working chambers and connecting each chamber formed between the inner and outer rotor to two control grooves 515 and 516 respectively on diametrically opposite sides inside the bearing member 550. The control grooves 515 and 516 communicate with pipes 517 and 518 for the admission and return of the oil. In this embodiment-as in the case of the previously described embodimentsthe inner and

outer rotors

505 and 502 respectively are positively coupled together by a coupling means not shown in the drawing.

The advantage of the proposed fluid coupling resides in that when used as a starting and safety coupling it is capable of transmitting high torques at low speeds efficiently, despite its extremely compact design.

The sealing devices between the working chambers may be modified in various ways. Thus the described flaps and sliding blocks could be replaced by rollers.

The volumetric capacity of the motor and hence its speed are controllable by known means, such as a change in the relative eccentricity of the rotors or by shifting the position of the ports which must then be provided in a bushing rotatably adjustable on the fixed pintle.

The proposed machine is also operable with compressed air instead of oil or even with steam. In principle all the above-described embodiments of the invention are also operable as pumps if the pintle is driven as the input shaft of the positive displacement pump Ad.

vantage can also be taken of the special property of the proposed machine that it is exceptionally suitable for an efiicient transmission of high torques.

While the fluid displacement machine has been shown and described in detail, it is obvious that this invention is not to be considered as being limited to the exact form disclosed, and that changes in detail and construction may be made therein within the scope of the invention, without departing from the spirit thereof.

What is claimed is:

1. A positive fluid displacement machine, particularly for use as an oil-hydraulic motor, oil-hydraulic pump or fluid coupling, comprising (a) an outer rotor and an inner rotor revolving about relatively eccentric axes, one of said rotors having flat peripheral faces,

(b) means positively coupling said two rotors together and (c) sealing means dividing the space enclosed between said rotors into a plurality of working chambers,

(d) said sealing mean includes sliding blocks slidably mounted on said fiat peripheral faces of the inner rotor or of the outer rotor, the outside with respect to the inside of which has the form of a polygonal prism and adapted to be urged into sealing contact with fixed fins attached to the inner or outer rotor, respectively,

(e) the inner and outer rotor hereby revolving at the same average speed and positively converting the fluid pressure exerted on the sliding blocks into rotary motion of the two rotors.

2. A machine as defined in claim 1 wherein there are two cooperating sliding blocks provided in each working chamber,

each said block being urged by spring means against the inner with respect to the outer rotor.

3. A machine as defined in claim 1 wherein said positive coupling means between the inner and outer rotor consists of a fixed projection from the inner rotor radially slidably and relatively defiectably received between two fixed guides projecting from the inside of the outer rotor.

4. A machine as defined in claim 3 wherein there are two cooperating sliding blocks provided in each working chamber,

5. A machine as defined in claim 2 wherein there are two cooperating sliding blocks provided in each chamber,

each block being urged by spring means against fixed fins on the inner and outer rotor respectively.

'6. A machine as defined in claim 5 wherein said sliding blocks are provided with positive retaining means which prevent said blocks from being lifted ofr said outer rotor.

7. A machine as defined in claim 2 wherein said sliding blocks are provided with positive retaining means which prevent said blocks from being lifted 01f said outer rotor.

8. A machine as defined in claim 1 wherein there is one sliding block only provided in each working chamber,

said block being urged by spring means against the inner with respect to the outer rotor.

References Cited UNITED STATES PATENTS 725,615 4/1903 Cooley 9168 914,627 3/ 1909 Alcorn 9168 2,011,338 8/1935 Hill. 2,061,950 11/1936 Ott 103-121 2,866,417 12/1958 Nubling. 3,306,226 2/1967 Walter.

DONLEY J. STOCKING, Primary Examiner WILBI JR J. GOODLIN, Assistant Examiner