EP1129293A1

EP1129293A1 - Rotary hydraulic machine

Info

Publication number: EP1129293A1
Application number: EP99954067A
Authority: EP
Inventors: Bernard René Charles Coeuret
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-11-05
Filing date: 1999-11-05
Publication date: 2001-09-05
Also published as: FR2785645B1; WO2000028218A1; FR2785645A1; AU1052200A

Abstract

The invention concerns a rotary hydraulic machine having a stator and a rotor with vanes defining chambers with variable volume with the stator. The stator (100) comprises a peripheral wall (130) centred on the axis (O) and provided with bosses (120) having an upstream ramp (121) and a downstream ramp (123) and a summit (122) located on a pitch circle (CP). The base (150) comprises two communicating orifices (151, 152) emerging in each cavity (140) in the proximity of the bosses (120). The rotor (200) comprises a body (210) with a circular outline (220) centred on the axis (O) in sealed contact with the summit (123) of the bosses (120), vane housings (230), each receiving a vane (240).

Description

The present invention relates to a rotary hydraulic machine having a stator and a vane rotor defining chambers of variable volume with the stator. Various rotary hydraulic machines are known which operate as a pump or as a motor depending on whether they are driven to deliver a fluid or whether they receive a working fluid to provide work.

The object of the present invention is to develop such a hydraulic machine, in order to obtain a machine which is very simple to produce and which operates efficiently, which can be used either as a pump or as a motor and whose direction of rotation is reversible for certain applications, by example as a motor to work as an engine brake or as a pump to flow in the opposite direction.

To this end, the invention relates to a rotary hydraulic machine of the type defined above, characterized in that: A) the stator comprises:

a circular peripheral wall centered on the axis of rotation and provided with bosses having an upstream ramp, a downstream ramp and a vertex situated on a pitch circle centered on the axis to delimit peripheral cavities,

- a background comprising:

* two communication orifices opening into each cavity in the vicinity of the bosses,

a balancing orifice associated with each cavity, opening into the face of the bottom in contact with the body of the rotor, these orifices being distributed over a basic circle,

- a cover closing the stator, B) the rotor comprises: - a body with a circular outline,

* centered on the axis and corresponding to the primitive circle,

* in tight contact with the top of the bosses,

* pallet housings, - each receiving a pallet in leaktight contact with the contour of the peripheral wall, and retracting into the housing to follow the ramps and the top of the bosses, - the bottom of which communicates with the balancing orifice at least on a part of the path of the pallet in the cavity, C) each pallet defining, in each cavity of the stator, a downstream chamber of variable volume with the peripheral wall, a ramp and the body, this volume being variable depending on the rotation of the rotor and of the pallet, this chamber being connected to the downstream communication orifice until the next pallet has passed over this communication orifice in this same cavity, D) each pallet defining in this cavity an upstream chamber of variable volume, with the peripheral wall, the ramp of a boss and the body of the stator, this chamber communicating with the upstream communication orifice of this same cavity as soon as the upstream pallet has passed é this upstream opening,

E) means for supplying fluid connected with at least some of the communication orifices, homologous according to the direction of rotation of the rotor, of the cavities for supplying working fluid to the chambers of variable volume, F) a balancing means to supply pressurized fluid to the balancing orifices.

Thanks to the circular shape of the stator wall which defines the machine cavities and the symmetrical shape of the rotor in rotation, the unbalanced masses are reduced to a minimum. It's just the pallets. The movement of these pallets is also limited to a relatively small excursion corresponding to the height of the peripheral cavities. These pallets are pressure balanced to, on the one hand seal the chambers which they delimit and, on the other hand, reduce the frictional forces and thus increase the efficiency of the machine.

According to an advantageous characteristic, each cavity comprises, associated with each of its ends, an orifice balancing plug intended to come into communication with the housing of each pallet in the phase of entry thereof into the cavity and in the output phase. This balancing orifice can be connected to a different source of balancing fluid depending on whether the balancing is done in the entry zone or in the exit zone of the cavity, when a pallet enters the cavity to receive the working fluid or to be transported by the first communication orifice associated with this cavity or when the pallet is in the second phase of its movement when it approaches the second communication orifice of the cavity which is the outlet orifice.

Indeed, whatever the operating mode of the hydraulic machine (pump or motor), the first orifice encountered by the pallet in its defined direction of rotation is the fluid inlet orifice and the second orifice at the the other end of the cavity is the fluid outlet orifice.

Depending on the pressures to which the pallet is subjected in the initial phase or in the final phase of its movement in the cavity, the balancing pressure acting on the base of the pallet is adapted by supplying it with a fluid at a pressure which may be different. This is particularly important when the machine uses a high pressure hydraulic fluid (pump or motor) because then at the end of movement, it is necessary to reduce the balancing pressure applied to the pallet so that it can pass the upstream ramp of the boss at the end of the cavity.

In some cases, this modification of the balancing pressure is not necessary when the slope of the upstream ramp of this second boss is relatively small. In this case, the source of balancing fluid supplying the two balancing orifices at the inlet and at the outlet of the cavity, are the same. It may even be a common hydraulic fluid line connected to these different balancing orifices.

The balancing orifices are located in the path of the pallet housings, these housings being at least partially open to communicate with these balancing orifices.

As in general the pallet housings and the direction of the pallets is radial or close to the radial direction, the balancing orifices are located on a radius close to or identical to the radius passing through the first and the second communication orifice.

According to another characteristic, the balancing orifice of a cavity is connected to the communication orifice of this same cavity. This simple solution reduces the balancing liquid lines which have to be made in the cover for supplying the various orifices. Indeed, it is interesting that the pressure of the liquid applied at a given time on the pallet (in the entry phase or the exit phase of the cavity) is also that used for its balancing, knowing that in all cases, the resulting force induced by the pressure applied to the base of the pallet in its housing and the pressure applied to a fraction of the surface of the end of the pallet in contact with the stator, always results from the difference in the surfaces , even for an identical pressure, to a resulting force applying the pallet in contact against the stator.

According to another advantageous characteristic, the base comprises a crown at least in one piece, applied by an adjustable pressure against the rotor and the corresponding side of the pallets. This mobile bottom solution in the form of a crown, preferably housed in the part of each cavity that does not include the bosses, constitutes a very interesting solution for sealing and balancing the forces applied to the vanes and the rotor during the machine functionment.

Although this is not essential in all cases, it is advantageous that the hydraulic machine has rotational symmetry and that the bosses are distributed regularly and thus delimit peripheral cavities occupying regular angular sectors. In the case where the supply of fluid to the first and the second balancing orifice of a cavity are separated for reasons of different pressure, it is advantageous to ensure the relief of these two orifices in the intermediate positions by supplying the cavity of the pallet with fluid, either at an intermediate pressure, or at the pressure of the first balancing orifice or that of the second balancing orifice, without this association being permanently fixed. This possibility results from a relay channel associated with each cavity sector, substantially in the middle (angular) of the sector and located on an intermediate circle, a secondary orifice opening into each relay channel, the secondary orifice being connected by means of pressure balancing to take over from the balancing orifices in the intermediate position of the pallet.

Thus, by dissociating the supply from the balancing orifices at each end of the cavity as well as the supply in the intermediate zone, it is possible to operate the machine reversibly in one direction or the other and this with a fluid. hydraulic at high pressures.

According to another advantageous characteristic, always in the direction of rotational symmetry, the pallet housings are distributed regularly and intersect the basic circle.

To allow supply with the relay channel of each cavity, the vane housings must cut the intermediate circle on which the relay channels are located.

According to another characteristic, to allow the different cavities (or sectors) to be operated either in parallel, or in series, or according to a parallel / series combination, the machine includes a switching device for selectively connecting the two communication orifices of each cavity to a source and return of fluid. Finally, to facilitate balancing and achieve sealing on the passage from the top of the bosses, an intermediate balancing orifice is provided with which the cavity of the pallet communicates in the phase of passage of the pallet on the top of 'a boss.

The present invention will be described hereinafter in more detail with the aid of different modes sheave ^¬ lisation schematically represented in the accompanying drawings in which: - Figure 1 is a view of an exemplary embodiment of the rotary hydraulic machine , showing the stator and the rotor, the stator cover having been removed,

FIG. 1A shows a variant of the embodiment of FIG. 1, FIG. 2 is a view of the stator without the rotor,

FIG. 3 is a view of the rotor,

FIG. 4 is a partial view of the machine in a first operating position, FIG. 5 is a partial view of the machine corresponding to that of FIG. 4 but in a different operating position,

- Figure 6 is an axial section of the machine according to Figure 1, - Figure 7 is an axial section similar to that of Figure 6, showing the circulation of fluids,

FIG. 8 is a sectional view of the switching device for the balancing means,

FIG. 9 is a schematic plan view of the switching device of FIG. 8 in a switching position,

FIG. 10 is a view similar to that of FIG. 9 for another switching position,

FIG. 11 is a diagram of the balancing ring and the means for supplying the pistons of this ring, FIG. 12 is a partial view similar to that of FIG. 4 of another embodiment of a machine according to the invention,

FIG. 13 is a view similar to that of FIG. 4 of a third embodiment of the machine according to the invention,

- Figure 14 is an alternative embodiment seen in axial section.

According to FIG. 1, the invention relates to a reversible rotary hydraulic machine operating as a hydraulic motor or as a hydraulic pump. This machine consists of a stator 100 and a rotor 200 carrying the axis 300,

For the rest of the description, it will be assumed that the rotor 200 rotates in the direction of arrow A. The expressions “upstream” and “downstream” will refer to this direction of rotation. As this direction of rotation is reversible, the terms "upstream" and "downstream" are also.

According to Figure 2, the stator 100 consists of a peripheral ring 110 possibly forming a flange with holes 111 for the passage of fixing bolts and / or assembly of the stator.

The peripheral ring 110 has bosses 120 distributed regularly along sectors of angle α, for example equal to 90 ° (Figure 2). These bosses 120 are identical. They consist of an upstream ramp 121, a peak 122 and a downstream ramp 123.

The apex 122 of all the bosses 120 is located on a primitive circle CP centered on the axis O of the machine. Between the bosses 120, the ring 110 has a circular cylindrical wall 130 centered on the axis O.

Between two consecutive bosses 120, the stator defines a cavity 140 with the wall 130 and the contour of the rotor, as it appears in FIG. 1. Thus, each angular sector is associated with a cavity.

The bottom 150 of the stator comprises, associated with each angular sector α, a first communication orifice 151 located near the downstream ramp 123 of a boss 120 and a second communication orifice 152 located near the upstream ramp 121 of the next boss 120. These orifices 151, 152 preferably have a bean shape, following the shape of the ramps 121, 123 and opening into the cavity 140. The bottom 150 also includes a relay channel

160 in the form of a circular groove, situated on an intermediate circle CI centered on the axis O and having an angular length defined subsequently in connection with the rotor. This relay channel 160 associated with each angular sector α or with each cavity 140 is located in the middle of the angular sector insofar as the other elements defining the cavity are symmetrical with respect to the bisector of this angular segment. The bridge channel 160 communicates with an orifice 170 ^¬ ondary opening through the base 150. The base 150 also includes a first and a second vent hole 181, 182 located on a base circle BC also centered on the axis O , preferably substantially on the radial axis of the orifice 151. The two balancing orifices 181, 182 are associated, one at the inlet, the other at the outlet of the cavity 140, in the direction of rotor rotation. The orifices are connected to a source of balancing fluid which may be different (pressure) for either of the two orifices 181, 182. An intermediate balancing orifice 185 may be provided at the top 122 of each boss 120, in the stator.

According to a simple embodiment, the two balancing orifices 181, 182 are connected to each of the communication orifices 151, 152 by a conduit 183, 184.

The description of the different elements of a stator sector above, also applies to the other sectors by circular permutation. This description will not be repeated and the various elements will bear, where appropriate, the same references as those of the angular sector of the stator described above. According to FIG. 1A, the variant of the previous embodiment concerns the length of the bosses, only one of which is shown here. The flat 1201 of this boss 120A is of circular cylindrical shape corresponding to the contour of the rotor 200. The circular flat 1201 provides better separation fa ^¬ vorable to an excellent seal between two successive cavities 140 especially as the parts of the cavities share and other of the boss 120A are at very different pressures ^¬ rents: one being in compression (discharge) and the other in depression (suction).

FIG. 3 shows the rotor 200 composed of a body 210 integral with the shaft 300. The body 210 has a circular contour 220 of radius equal to that of the pitch circle CP of the stator 100. The circular contour 220 of the rotor 210 is in contact with the top 122 of the stator bosses 120. This contact is sealed up to a certain pressure defined by the operating conditions provided for the hydraulic machine. The body 210 comprises pallet housings 230 directed substantially in the radial direction and receiving pallets 240. The housings 230 open at least on one of the faces of the rotor 200, preferably over a significant part of their height, or even over their entire height, so that these housings can communicate with the balancing orifices 181, 182 and the relay channels 160 of the bottom 150 of the stator. According to the invention, the number of box elements ^¬ 230 and pallet 240, regularly distributed by Rap- port rotor 200, is at least equal to the number of cavities 140 of the stator 100 so that, regardless of the rotational position of the rotor 200, at least one pallet 240 is located in a cavity 140 of the stator 100 separating the first orifice 151 from the second 152. Interestingly, the number of pallets is different from an integer multiple of the number of bosses so that all the bosses are not occupied simultaneously by pallets. This allows torque variations to be distributed more evenly over one rotation. According to the example, the housings 230 are directed radially and the pallets 240 slide radially therein. This position is most advantageous for a reversible hydraulic machine, that is to say capable of turn in the direction of rotation A indicated above or in the opposite direction of rotation. However, in some cases, it can, as required in particular congestion, provide housing and pallets a direction dif- annuity, essentially turned towards the center but not rigoureu ^¬ radial versa.

When the rotor 200 is mounted in the stator 100, the vanes 240 are placed as shown in Figure 1; they are applied, by pressure, against the contour 130, 121, 122, 123 of the cavities 140 of the stator 100 and delimit between them, and with the stator and the contour of the rotor, chambers of variable volume as will be described below. after.

For the rotor 200 of FIG. 2, the vanes 240 occupy different positions and thus release a variable volume 231 in their housing 230, with their bottom 241. Their outer end 242, intended to come into contact with the wall of the stator and the ramps bosses, is rounded to more easily follow this surface. The radius of curvature of the top of the pallets is not necessarily uniform. It can be variable but, in general, the radius of curvature is as large as possible to get as close as possible to the radius of curvature of the wall 130 and that of the ramps 121, 123. Sealing means, not shown, can be provided on the top of the pallets.

The description of the operation of the hydraulic machine will be made using the partial views of FIGS. 4 and 5. To facilitate this description, the references of the elements of the stator and of the rotor described above will bear indices of increasing order in the direction of rotation A to allow them to be distinguished more easily in their operation.

According to Figures 4 and 5, the parts of the stator are assigned the index (n) for the entire appearing cavity, the index (n-1) for the upstream cavity and the index (n + 1) for the downstream cavity. For the 240 pallets we will use the indices (p) and (p + 1) for the two pallets located in the cavity 140n, the index (p-1) for the downstream pallet and the index (p + 2) for the first upstream pallet.

According to FIG. 4, the rotor 200 rotates in the direction of arrow A. The pallet 240p descends the ramp 123n from the boss 120n and releases the opening 151n. The pallet 240p defines, with the peripheral wall 130n, the ramp 123n and the wall part 220p of the body 210 of the rotor 200, a chamber CHq into which the communication orifice 151n opens. The hydraulic fluid arrives through this orifice in this chamber CHq and pushes the pallet 240p in the direction of arrow A, thus driving the rotor 200. As the pallet 240p rotates while pressing against the wall 130n of the cavity 140n, the volume of the chamber CHq increases and the hydraulic fluid continues to arrive, (fig. 5). Then, the pallet 240p-l passes the top 122n of the boss 120n and begins to pass over the orifice 151n. The 240p-l pallet thus defines a new chamber, downstream of the CHq chamber, between the 240p and 240p-l pallets. When the pallet 240p-l arrives in the position of the pallet 240p of FIG. 4, the chamber CHq no longer changes volume and moreover the pallet 240p-l then covers the orifice 151n. The next CHq-1 chamber develops and the operations are repeated as the next pallets arrive.

Figure 4 shows the CHq + 1 chamber which is located upstream of the CHq chamber. This chamber CHq + 1 has arrived at its constant volume since the vanes 240p, 240p + 1, which delimit it, occupy their extreme position, pressing against the peripheral wall 130n of the cavity 140n.

When the upstream pallet 240P clears the upstream communication orifice 152n, the liquid from the chamber CHq + 1 begins to exit through this upstream communication orifice 152n. This evacuation continues since, as the rotation progresses, the volume of the chamber CHq + 1 decreases; the 240p + l pallet starts the ramp 121n + l, passes the summit 122n + l then descends on the other side along the downstream ramp 123n + l. During this time, the 240p pallet approaches the position occupied in FIG. 4 by the 240p + 1 pallet. The movement continues like this. FIG. 4 also shows the pallet 240P + 2 which delimits, with the ramp 123n + l, a chamber CHq + 3 which corresponds to the chamber CHq and is in the same situation at the start of filling with hydraulic liquid supplied by the upstream communication port 151p + l.

During the movement of the pallets 240p + l, p + 2, the volume 231p of the housing 230p of the pallet 240p varies and it is kept under pressure by the means of the invention. In fact, when the volume 231p passes over the first balancing orifice 181n, which communicates with the communication orifice 151p via the conduit 183n, the hydraulic fluid arrives in the volume 231p and exerts its pressure thereon on the bottom 241p of the piston 240p to apply its other end 242p against the wall 130n of the cavity 140n. When as a result of the rotation of the rotor 200, the volume 231p is no longer in communication with the balancing orifice 181n, the volume 231p remains closed and constant since it contains liquid. It is at this moment the phase in which the 240p pallet is pressed against the circular contour 130n of the stator 100. A resumption of supply of the volume 231p is ensured when the volume 231p arrives on the relay channel lβOn which communicates by orifice 170n with the source of hydraulic fluid. This communication between the relay channel 160n and the volume 231p of the housing 230p of the pallet 240p continues during the rotation phase until the volume 231p leaves the relay channel 160n. But, at this moment, we are at the end of the journey at constant volume of the chamber CHq + 1 and the volume 231p arrives in communication with the second balancing orifice 182n connected by the conduit 184n to the downstream communication orifice 152n which corresponds to the outlet of the liquid. The liquid can therefore escape from the volume 231p to allow the pallet 240p to retract into its housing 230p and follow the downstream ramp 121n + l. This reduction, or even cancellation of the pressure of the liquid in the volume 231p allows the pallet 240p to follow the ramp 121n + l and to retract into its housing to allow the rotor to pass under the top 122n + l. This is necessary in case of high pressure and for a relatively large 121n + l ramp.

The operation described above was carried out on the assumption of a hydraulic fluid under pressure, that is to say of a rotary hydraulic machine operating as a hydraulic motor. The operation is the same for a hydraulic liquid under vacuum (negative algebraic pressure), which corresponds in a way to the operation of the rotary hydraulic machine like a pump. The suction energy is supplied to the rotor which drives the paddles. Under these conditions, if the direction of rotation of the rotor A is the same, the chamber CHq constitutes a suction chamber which fills with aspirated liquid to be discharged under a certain pressure through the second orifice or downstream communication orifice 152n.

It should also be noted that the various cavities 140 can be connected in parallel or in series or alternatively in a combined series, parallel connection. The parallel connection of the chambers 140n, 140n + l means that the downstream port 152n communicates with the upstream port 151n + l which follows directly. Likewise, the upstream port 151n is placed in communication with the upstream port 152n-1.

For full parallel connection, all upstream ports are connected to the same source of hydraulic fluid (pressure or vacuum) and all downstream communication ports are connected to a common outlet. Combinations of these two extreme assemblies (either all in series, or all in parallel) can also be envisaged according to the desired operation for the hydraulic machine, that is to say a choice between a high rotation speed and a low torque in the case of a motor or vice versa with a low speed of rotation and a high torque; in the case of a pump driven by a drive means without reduction gear, the speed of rotation will be high and the flow rate low or conversely the speed of rotation drive may be low but then the flow greater. Figure 6 is an axial sectional view of the hydraulic machine of Figures 1 to 3 showing the peripheral ring 110 with the bottom 150 and the cover 180. The bottom 150 carries a flange 158 and it also houses the shaft 300 by the intermediate of a rolling bearing 301. FIG. 6 is cut at the level of the pallets 240, one of which is in contact with the boss 120 (top pallet) while the other is in contact with the peripheral wall 130. This the latter leaves the free volume 231. The rotor 200 is applied against a fixed peripheral ring 280, itself subjected to the action of jacks 401, 402. The ring 280 is for example a segmented peripheral ring or in one piece. These jacks 401, 402 are connected by a hydraulic fluid channel 403 to the source of hydraulic fluid to exert on the inner ring 280, a thrust ensuring the balancing and sealing of the chambers delimited by the pallets 240.

The supply is made in the example shown from the hydraulic fluid inlet 500 which arrives in the communication orifice 151 at this time overlapped by the lower pallet 240 (according to FIG. 6). The orifice 500 also communicates with the balancing orifice 180 by the channel 404 as well as by a channel 405 connected to a switching device 600 provided with a floating piston 601 housed in a chamber 602. When the pressurized liquid arrives through the inlet 500 and the conduit 405, the pressure pushes the floating piston 606 back into the position shown in FIG. 6, thus freeing the channel 406 which arrives at the orifice 170 communicating with the relay channel 160. The return of the liquid hydraulics is done through the downstream communication orifice 152 connected to the cover 501. As the motor is reversible, the outlet pipe 501 can also constitute the arrival of pressurized liquid, which is why this pipe is connected by a conduit 410 at the other end of the switching device 600. When the pressure arrives through the conduit 410 it does not arrive through the conduit 405 and the piston 601 passes into the other position closing at this time the channel 405 and mettan t in communication conduit 410 with conduit 406 to supply the communication and balancing orifices other than those supplied previously. The axis 300 and the cover 180 also comprise a pipe 302 for collecting leaks which passes through the pipe 420 of the cover 180.

The cover 180 is also provided with non-detailed means making it possible to switch the various communication orifices 151, 152 to connect the cavities in series or in parallel or according to a mixed combination as has already been mentioned above. These means will be described using FIGS. 8 to 10.

The circulation of liquid is represented by arrows in FIG. 7, without all the references being given in this figure for the purpose of simplification. FIG. 8 shows in section a switching device 700 which is mounted against the left face of the cover 180 in FIG. 6. This switching device comprises four switching members 710, associated with each of the four sectors of the rotor / stator in the case of the example of the previous figures. These switching devices are identical and only one will be described.

The switching member 710 consists of an axis 711 and a body 712 with a diametrically traversing channel

713 and two elbow-shaped cavities 714 (see FIG. 9) which each connect the lateral face to the lower part of the head 712 thus constituting a 90 ° communication elbow. The switching member 710 can switch between the position shown and a position rotated 90 °. In one position, the through channel 713 connects two pipes and in the other, each of the communication elbows

714 ensures communication as will be described.

On its right side, the switching device 700 of FIG. 8 has orifices corresponding to the orifices 500, 501 of FIG. 6. These orifices are shown close together in FIG. 8 for the switching member 710 occupying in the drawing the central position whereas in FIG. 6 these orifices 500, 501 are diametrically opposite since they do not belong to the same sector of the hydraulic machine.

Figures 9 and 10 give examples of the switching position. In FIG. 9, all the switching members

710 are oriented in switching in the same way. They connect the central toric channel 720 by the conduit 713 to the orifice 500. The latter overlaps the toric channel 730 but is in a different plane and does not communicate with it.

Figure 10 shows a different switching position.

Figure 11 is a schematic view of part of the hydraulic circuits of Figure 6. The ring 280 thus shown, bypasses the four bosses not referenced in this figure. The crown is supported by pistons 401. Depending on the case, these pistons could also be constituted by a single crown passing below the re-entrant parts of the crown 280 corresponding to the boss of the stator. This FIG. 11 shows in particular the inputs / outputs 500, 501 communicating with the floating piston 600 for one of the sectors of the hydraulic machine. This arrangement is repeated four times.

The supply of pistons 401 with fluid takes place through the conduit 403 common each time to two pistons.

Figure 12 shows schematically in the manner of Figure 4, another embodiment of a hydraulic machine. This embodiment includes very little accentuated bosses, the ramps of which have slight slopes so that the problem of de-pressurizing the pallets attacking the upstream ramps no longer arises. This allows a simpler embodiment which does not include a relay channel, the balancing orifices 181A all opening into a common balancing channel 182A. In more detail, this hydraulic machine comprises a stator 100A and a rotor 200A fitted with movable 240A vanes in housings 230A. The 231A volumes at the bottom of the 230A housings communicate with the crown balancing 182A. The bosses 120A have a relatively small height with ramps 121A, 122A relatively slightly inclined. The other means of this machine are the same as those described above and have the same references with the suffix A.

This machine with cavities 140A of low height and therefore of chambers CHq + 1, CHq, of relatively reduced volume, is a machine capable of turning rapidly.

FIG. 9 shows another alternative embodiment which differs from the previous variants in the production of the bosses 120B. This machine is intended to operate with relatively high pressures. Elements identical to those of the hydraulic machine already described have the same references as above, with the suffix B.

The boss 120B is in fact constituted by a veil defining the ramps 121B, 123B and the top 122B with behind the veil a chamber 124B receiving a fluid under high pressure. This chamber comprises a support cylinder 125B which comes behind the part of the web at the level of the top 122B. This cylinder 125B is preferably supported by an adjustable screw 126B which exerts on the cylinder 125B a force limiting the exhaust stroke of the cylinder 125B in the direction directed towards the outside according to the embodiment shown here. The pressure of the liquid which prevails in the chamber 124B makes it possible to adjust the pressure for pressing the crown 122B against the external contour 220B of the body 210B of the rotor 200B.

Figure 14 shows in axial section a variant of the embodiment shown in Figure 6; elements identical or analogous to those already described bear the same references and their description will not be repeated.

This variant differs from the embodiment of FIG. 6 by two flat rings 211, 212 bordering the rotor 210 for guiding the pallets 240 laterally over a certain height, thereby improving their operation and the sealing of the chambers or cavities delimited by the pallets. These rings 211, 212 are each provided with a seal turning 213, 214. According to the embodiment shown, these rings are separate parts of the rotor 210 and are fixed there by screws 215.

In this embodiment, the pallets 240 are balanced from a central pipe 900 connected to radial pipes 901 in the rotor 240 and opening at the base of the housings 230 of the pallets 240. The pipe 900 is connected to the hydraulic fluid inlet 500 which is at operating pressure.

Claims

R E V E N D I C A T I O N S 1 °) Rotary hydraulic machine having a stator and a vane rotor defining chambers of variable volume with the stator, characterized in that

A) the stator (100) includes:

- a circular peripheral wall (130) centered on the axis of rotation (0) and provided with bosses (120) having an upstream ramp (121), a downstream ramp (123) and a vertex (122) located on a primitive circle (CP) centered on the axis (O) to delimit peripheral cavities (140),

- a bottom (150) comprising:

two communication orifices (151, 152) opening into each cavity (140) in the vicinity of the bosses (120),

* a balancing orifice (181, 182) associated with each cavity (140), opening into the face of the bottom (150) in contact with the body (210) of the rotor (200), these orifi ^¬ these being distributed over a base circle (CB), - a cover closing the stator (100),

B) the rotor (200) comprises:

- a body (210) with circular outline (220),

* centered on the axis (O) and corresponding to the primitive circle (CP), * in leaktight contact with the top (123) of the bosses (120),

* pallet housings (230),

- each receiving a pallet (240) in leaktight contact with the contour (130, 121, 122, 123) of the peripheral wall (130), and retracting into the housing (230) to follow the ramps (121, 123) and the top (122) of the bosses (120),

- the bottom of which communicates with the balancing orifice (180, 181) at least on a part of the path of the pallet (240) in the cavity (140),

C) each pallet (240) defining, in each cavity (140) of the stator (100), a downstream chamber (Chq + 1) volume varia ^¬ ble with the peripheral wall (130), a ramp (121) and the body (210), this volume being variable as a function of the rotation of the rotor (200) and of the pallet (240), this chamber being connected to the downstream communication orifice (151) until the next pallet (240) is passed over this communication orifice (151) in this same cavity (140),

D) each pallet (240) defining in this cavity (140) an upstream chamber (Chq + 2) of variable volume, with the peripheral wall (130), the ramp (123) of a boss (120) and the body ( 210) of the stator (200), this chamber communicating with the upstream communication orifice (152) of this same cavity (140) as soon as the upstream pallet has passed this upstream orifice (152),

E) means for supplying fluid connected with at least some of the communication orifices (151), homologous according to the direction of rotation of the rotor, cavities for supplying working fluid to the chambers of variable volume (1),

F) a balancing means for supplying fluid under pressure to the balancing orifices.

2) hydraulic machine according to claim 1, characterized in that each cavity (140) comprises, associated with each of its ends, a balancing orifice (181, 182) intended to come into communication with the housing (230 ) of each pallet (240) in the entry phase thereof (240) in the cavity and in the exit phase.

3) hydraulic machine according to claim 1, characterized in that the balancing orifice (181, 182) of a cavity is connected to the communication orifice (151, 152) of this same cavity (140).

4) hydraulic machine according to claim 1, characterized in that the base comprises a crown (280) at least in one piece, applied by an adjustable pressure against the rotor and the corresponding side of the pallets.

5) hydraulic machine according to claim 1, characterized in that the bosses (120) are distributed regularly, delimiting peripheral cavities (140) occupying regular angular sectors (α).

6) hydraulic machine according to claim 1, characterized by a relay channel (160) associated with each sector (α) of cavity (140), substantially in the middle (angular) of the sector and located on an intermediate circle (CI), a secondary orifice (170) opening into each relay channel (160), the secondary orifice being connected to the pressure balancing means to take over from the balancing orifices (181, 182) in the intermediate position of the pallet (240).

7) hydraulic machine according to claim 1, characterized in that the housings (230) with vanes are distributed regularly and intersect the base circle (CB).

8 °) hydraulic machine according to claims 1 and 6, characterized in that the pallet housings (230) intersect the intermediate circle (CI).

9 °) hydraulic machine according to claim 1, characterized in that it comprises a switching device (700) for selectively connecting the two communication orifices (151, 152) of each cavity (140) to a source and a return of fluid.

10 °) hydraulic machine according to claim 1, characterized in that the stator (100) has an intermediate balancing orifice (185) associated with each peak (122) of boss (120) to balance the pallet (240) as the top (122) of the boss passes.

11 °) hydraulic machine according to claim 1, characterized in that the rotor (210) is bordered by two rings (211, 212) fixed to the rotor and laterally delimiting the housings (230) of the pallets (240).